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Revision 1.61 by dl, Thu Sep 13 10:41:37 2012 UTC vs.
Revision 1.112 by dl, Sat Jul 20 16:50:04 2013 UTC

# Line 5 | Line 5
5   */
6  
7   package jsr166e;
8 < import jsr166e.LongAdder;
8 >
9   import jsr166e.ForkJoinPool;
10 import jsr166e.ForkJoinTask;
10  
11 < import java.util.Comparator;
11 > import java.io.ObjectStreamField;
12 > import java.io.Serializable;
13 > import java.lang.reflect.ParameterizedType;
14 > import java.lang.reflect.Type;
15 > import java.util.AbstractMap;
16   import java.util.Arrays;
14 import java.util.Map;
15 import java.util.Set;
17   import java.util.Collection;
18 < import java.util.AbstractMap;
19 < import java.util.AbstractSet;
20 < import java.util.AbstractCollection;
20 < import java.util.Hashtable;
18 > import java.util.Comparator;
19 > import java.util.ConcurrentModificationException;
20 > import java.util.Enumeration;
21   import java.util.HashMap;
22 + import java.util.Hashtable;
23   import java.util.Iterator;
24 < import java.util.Enumeration;
24 < import java.util.ConcurrentModificationException;
24 > import java.util.Map;
25   import java.util.NoSuchElementException;
26 + import java.util.Set;
27   import java.util.concurrent.ConcurrentMap;
27 import java.util.concurrent.ThreadLocalRandom;
28 import java.util.concurrent.locks.LockSupport;
29 import java.util.concurrent.locks.AbstractQueuedSynchronizer;
28   import java.util.concurrent.atomic.AtomicReference;
29 <
30 < import java.io.Serializable;
29 > import java.util.concurrent.atomic.AtomicInteger;
30 > import java.util.concurrent.locks.LockSupport;
31 > import java.util.concurrent.locks.ReentrantLock;
32  
33   /**
34   * A hash table supporting full concurrency of retrievals and
# Line 43 | Line 42 | import java.io.Serializable;
42   * interoperable with {@code Hashtable} in programs that rely on its
43   * thread safety but not on its synchronization details.
44   *
45 < * <p> Retrieval operations (including {@code get}) generally do not
45 > * <p>Retrieval operations (including {@code get}) generally do not
46   * block, so may overlap with update operations (including {@code put}
47   * and {@code remove}). Retrievals reflect the results of the most
48   * recently <em>completed</em> update operations holding upon their
# Line 64 | Line 63 | import java.io.Serializable;
63   * that may be adequate for monitoring or estimation purposes, but not
64   * for program control.
65   *
66 < * <p> The table is dynamically expanded when there are too many
66 > * <p>The table is dynamically expanded when there are too many
67   * collisions (i.e., keys that have distinct hash codes but fall into
68   * the same slot modulo the table size), with the expected average
69   * effect of maintaining roughly two bins per mapping (corresponding
# Line 83 | Line 82 | import java.io.Serializable;
82   * expected {@code concurrencyLevel} as an additional hint for
83   * internal sizing.  Note that using many keys with exactly the same
84   * {@code hashCode()} is a sure way to slow down performance of any
85 < * hash table.
85 > * hash table. To ameliorate impact, when keys are {@link Comparable},
86 > * this class may use comparison order among keys to help break ties.
87 > *
88 > * <p>A {@link Set} projection of a ConcurrentHashMapV8 may be created
89 > * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
90 > * (using {@link #keySet(Object)} when only keys are of interest, and the
91 > * mapped values are (perhaps transiently) not used or all take the
92 > * same mapping value.
93   *
94   * <p>This class and its views and iterators implement all of the
95   * <em>optional</em> methods of the {@link Map} and {@link Iterator}
96   * interfaces.
97   *
98 < * <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
98 > * <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
99   * does <em>not</em> allow {@code null} to be used as a key or value.
100   *
101 + * <p>ConcurrentHashMapV8s support a set of sequential and parallel bulk
102 + * operations that are designed
103 + * to be safely, and often sensibly, applied even with maps that are
104 + * being concurrently updated by other threads; for example, when
105 + * computing a snapshot summary of the values in a shared registry.
106 + * There are three kinds of operation, each with four forms, accepting
107 + * functions with Keys, Values, Entries, and (Key, Value) arguments
108 + * and/or return values. Because the elements of a ConcurrentHashMapV8
109 + * are not ordered in any particular way, and may be processed in
110 + * different orders in different parallel executions, the correctness
111 + * of supplied functions should not depend on any ordering, or on any
112 + * other objects or values that may transiently change while
113 + * computation is in progress; and except for forEach actions, should
114 + * ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry}
115 + * objects do not support method {@code setValue}.
116 + *
117 + * <ul>
118 + * <li> forEach: Perform a given action on each element.
119 + * A variant form applies a given transformation on each element
120 + * before performing the action.</li>
121 + *
122 + * <li> search: Return the first available non-null result of
123 + * applying a given function on each element; skipping further
124 + * search when a result is found.</li>
125 + *
126 + * <li> reduce: Accumulate each element.  The supplied reduction
127 + * function cannot rely on ordering (more formally, it should be
128 + * both associative and commutative).  There are five variants:
129 + *
130 + * <ul>
131 + *
132 + * <li> Plain reductions. (There is not a form of this method for
133 + * (key, value) function arguments since there is no corresponding
134 + * return type.)</li>
135 + *
136 + * <li> Mapped reductions that accumulate the results of a given
137 + * function applied to each element.</li>
138 + *
139 + * <li> Reductions to scalar doubles, longs, and ints, using a
140 + * given basis value.</li>
141 + *
142 + * </ul>
143 + * </li>
144 + * </ul>
145 + *
146 + * <p>These bulk operations accept a {@code parallelismThreshold}
147 + * argument. Methods proceed sequentially if the current map size is
148 + * estimated to be less than the given threshold. Using a value of
149 + * {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
150 + * of {@code 1} results in maximal parallelism by partitioning into
151 + * enough subtasks to fully utilize the {@link
152 + * ForkJoinPool#commonPool()} that is used for all parallel
153 + * computations. Normally, you would initially choose one of these
154 + * extreme values, and then measure performance of using in-between
155 + * values that trade off overhead versus throughput.
156 + *
157 + * <p>The concurrency properties of bulk operations follow
158 + * from those of ConcurrentHashMapV8: Any non-null result returned
159 + * from {@code get(key)} and related access methods bears a
160 + * happens-before relation with the associated insertion or
161 + * update.  The result of any bulk operation reflects the
162 + * composition of these per-element relations (but is not
163 + * necessarily atomic with respect to the map as a whole unless it
164 + * is somehow known to be quiescent).  Conversely, because keys
165 + * and values in the map are never null, null serves as a reliable
166 + * atomic indicator of the current lack of any result.  To
167 + * maintain this property, null serves as an implicit basis for
168 + * all non-scalar reduction operations. For the double, long, and
169 + * int versions, the basis should be one that, when combined with
170 + * any other value, returns that other value (more formally, it
171 + * should be the identity element for the reduction). Most common
172 + * reductions have these properties; for example, computing a sum
173 + * with basis 0 or a minimum with basis MAX_VALUE.
174 + *
175 + * <p>Search and transformation functions provided as arguments
176 + * should similarly return null to indicate the lack of any result
177 + * (in which case it is not used). In the case of mapped
178 + * reductions, this also enables transformations to serve as
179 + * filters, returning null (or, in the case of primitive
180 + * specializations, the identity basis) if the element should not
181 + * be combined. You can create compound transformations and
182 + * filterings by composing them yourself under this "null means
183 + * there is nothing there now" rule before using them in search or
184 + * reduce operations.
185 + *
186 + * <p>Methods accepting and/or returning Entry arguments maintain
187 + * key-value associations. They may be useful for example when
188 + * finding the key for the greatest value. Note that "plain" Entry
189 + * arguments can be supplied using {@code new
190 + * AbstractMap.SimpleEntry(k,v)}.
191 + *
192 + * <p>Bulk operations may complete abruptly, throwing an
193 + * exception encountered in the application of a supplied
194 + * function. Bear in mind when handling such exceptions that other
195 + * concurrently executing functions could also have thrown
196 + * exceptions, or would have done so if the first exception had
197 + * not occurred.
198 + *
199 + * <p>Speedups for parallel compared to sequential forms are common
200 + * but not guaranteed.  Parallel operations involving brief functions
201 + * on small maps may execute more slowly than sequential forms if the
202 + * underlying work to parallelize the computation is more expensive
203 + * than the computation itself.  Similarly, parallelization may not
204 + * lead to much actual parallelism if all processors are busy
205 + * performing unrelated tasks.
206 + *
207 + * <p>All arguments to all task methods must be non-null.
208 + *
209 + * <p><em>jsr166e note: During transition, this class
210 + * uses nested functional interfaces with different names but the
211 + * same forms as those expected for JDK8.</em>
212 + *
213   * <p>This class is a member of the
214   * <a href="{@docRoot}/../technotes/guides/collections/index.html">
215   * Java Collections Framework</a>.
216   *
99 * <p><em>jsr166e note: This class is a candidate replacement for
100 * java.util.concurrent.ConcurrentHashMap.  During transition, this
101 * class declares and uses nested functional interfaces with different
102 * names but the same forms as those expected for JDK8.<em>
103 *
217   * @since 1.5
218   * @author Doug Lea
219   * @param <K> the type of keys maintained by this map
220   * @param <V> the type of mapped values
221   */
222 < public class ConcurrentHashMapV8<K, V>
223 <    implements ConcurrentMap<K, V>, Serializable {
222 > public class ConcurrentHashMapV8<K,V> extends AbstractMap<K,V>
223 >    implements ConcurrentMap<K,V>, Serializable {
224      private static final long serialVersionUID = 7249069246763182397L;
225  
226      /**
227 <     * A partitionable iterator. A Spliterator can be traversed
228 <     * directly, but can also be partitioned (before traversal) by
229 <     * creating another Spliterator that covers a non-overlapping
117 <     * portion of the elements, and so may be amenable to parallel
118 <     * execution.
119 <     *
120 <     * <p> This interface exports a subset of expected JDK8
121 <     * functionality.
122 <     *
123 <     * <p>Sample usage: Here is one (of the several) ways to compute
124 <     * the sum of the values held in a map using the ForkJoin
125 <     * framework. As illustrated here, Spliterators are well suited to
126 <     * designs in which a task repeatedly splits off half its work
127 <     * into forked subtasks until small enough to process directly,
128 <     * and then joins these subtasks. Variants of this style can also
129 <     * be used in completion-based designs.
130 <     *
131 <     * <pre>
132 <     * {@code ConcurrentHashMapV8<String, Long> m = ...
133 <     * // split as if have 8 * parallelism, for load balance
134 <     * int n = m.size();
135 <     * int p = aForkJoinPool.getParallelism() * 8;
136 <     * int split = (n < p)? n : p;
137 <     * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
138 <     * // ...
139 <     * static class SumValues extends RecursiveTask<Long> {
140 <     *   final Spliterator<Long> s;
141 <     *   final int split;             // split while > 1
142 <     *   final SumValues nextJoin;    // records forked subtasks to join
143 <     *   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
144 <     *     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
145 <     *   }
146 <     *   public Long compute() {
147 <     *     long sum = 0;
148 <     *     SumValues subtasks = null; // fork subtasks
149 <     *     for (int s = split >>> 1; s > 0; s >>>= 1)
150 <     *       (subtasks = new SumValues(s.split(), s, subtasks)).fork();
151 <     *     while (s.hasNext())        // directly process remaining elements
152 <     *       sum += s.next();
153 <     *     for (SumValues t = subtasks; t != null; t = t.nextJoin)
154 <     *       sum += t.join();         // collect subtask results
155 <     *     return sum;
156 <     *   }
157 <     * }
158 <     * }</pre>
227 >     * An object for traversing and partitioning elements of a source.
228 >     * This interface provides a subset of the functionality of JDK8
229 >     * java.util.Spliterator.
230       */
231 <    public static interface Spliterator<T> extends Iterator<T> {
231 >    public static interface ConcurrentHashMapSpliterator<T> {
232          /**
233 <         * Returns a Spliterator covering approximately half of the
234 <         * elements, guaranteed not to overlap with those subsequently
235 <         * returned by this Spliterator.  After invoking this method,
236 <         * the current Spliterator will <em>not</em> produce any of
237 <         * the elements of the returned Spliterator, but the two
238 <         * Spliterators together will produce all of the elements that
239 <         * would have been produced by this Spliterator had this
240 <         * method not been called. The exact number of elements
241 <         * produced by the returned Spliterator is not guaranteed, and
171 <         * may be zero (i.e., with {@code hasNext()} reporting {@code
172 <         * false}) if this Spliterator cannot be further split.
173 <         *
174 <         * @return a Spliterator covering approximately half of the
175 <         * elements
176 <         * @throws IllegalStateException if this Spliterator has
177 <         * already commenced traversing elements
233 >         * If possible, returns a new spliterator covering
234 >         * approximately one half of the elements, which will not be
235 >         * covered by this spliterator. Returns null if cannot be
236 >         * split.
237 >         */
238 >        ConcurrentHashMapSpliterator<T> trySplit();
239 >        /**
240 >         * Returns an estimate of the number of elements covered by
241 >         * this Spliterator.
242           */
243 <        Spliterator<T> split();
243 >        long estimateSize();
244 >
245 >        /** Applies the action to each untraversed element */
246 >        void forEachRemaining(Action<? super T> action);
247 >        /** If an element remains, applies the action and returns true. */
248 >        boolean tryAdvance(Action<? super T> action);
249      }
250  
251 +    // Sams
252 +    /** Interface describing a void action of one argument */
253 +    public interface Action<A> { void apply(A a); }
254 +    /** Interface describing a void action of two arguments */
255 +    public interface BiAction<A,B> { void apply(A a, B b); }
256 +    /** Interface describing a function of one argument */
257 +    public interface Fun<A,T> { T apply(A a); }
258 +    /** Interface describing a function of two arguments */
259 +    public interface BiFun<A,B,T> { T apply(A a, B b); }
260 +    /** Interface describing a function mapping its argument to a double */
261 +    public interface ObjectToDouble<A> { double apply(A a); }
262 +    /** Interface describing a function mapping its argument to a long */
263 +    public interface ObjectToLong<A> { long apply(A a); }
264 +    /** Interface describing a function mapping its argument to an int */
265 +    public interface ObjectToInt<A> {int apply(A a); }
266 +    /** Interface describing a function mapping two arguments to a double */
267 +    public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
268 +    /** Interface describing a function mapping two arguments to a long */
269 +    public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
270 +    /** Interface describing a function mapping two arguments to an int */
271 +    public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }
272 +    /** Interface describing a function mapping two doubles to a double */
273 +    public interface DoubleByDoubleToDouble { double apply(double a, double b); }
274 +    /** Interface describing a function mapping two longs to a long */
275 +    public interface LongByLongToLong { long apply(long a, long b); }
276 +    /** Interface describing a function mapping two ints to an int */
277 +    public interface IntByIntToInt { int apply(int a, int b); }
278 +
279      /*
280       * Overview:
281       *
# Line 189 | Line 286 | public class ConcurrentHashMapV8<K, V>
286       * the same or better than java.util.HashMap, and to support high
287       * initial insertion rates on an empty table by many threads.
288       *
289 <     * Each key-value mapping is held in a Node.  Because Node fields
290 <     * can contain special values, they are defined using plain Object
291 <     * types. Similarly in turn, all internal methods that use them
292 <     * work off Object types. And similarly, so do the internal
293 <     * methods of auxiliary iterator and view classes.  All public
294 <     * generic typed methods relay in/out of these internal methods,
295 <     * supplying null-checks and casts as needed. This also allows
296 <     * many of the public methods to be factored into a smaller number
297 <     * of internal methods (although sadly not so for the five
298 <     * variants of put-related operations). The validation-based
299 <     * approach explained below leads to a lot of code sprawl because
300 <     * retry-control precludes factoring into smaller methods.
289 >     * This map usually acts as a binned (bucketed) hash table.  Each
290 >     * key-value mapping is held in a Node.  Most nodes are instances
291 >     * of the basic Node class with hash, key, value, and next
292 >     * fields. However, various subclasses exist: TreeNodes are
293 >     * arranged in balanced trees, not lists.  TreeBins hold the roots
294 >     * of sets of TreeNodes. ForwardingNodes are placed at the heads
295 >     * of bins during resizing. ReservationNodes are used as
296 >     * placeholders while establishing values in computeIfAbsent and
297 >     * related methods.  The types TreeBin, ForwardingNode, and
298 >     * ReservationNode do not hold normal user keys, values, or
299 >     * hashes, and are readily distinguishable during search etc
300 >     * because they have negative hash fields and null key and value
301 >     * fields. (These special nodes are either uncommon or transient,
302 >     * so the impact of carrying around some unused fields is
303 >     * insignificant.)
304       *
305       * The table is lazily initialized to a power-of-two size upon the
306       * first insertion.  Each bin in the table normally contains a
# Line 208 | Line 308 | public class ConcurrentHashMapV8<K, V>
308       * Table accesses require volatile/atomic reads, writes, and
309       * CASes.  Because there is no other way to arrange this without
310       * adding further indirections, we use intrinsics
311 <     * (sun.misc.Unsafe) operations.  The lists of nodes within bins
312 <     * are always accurately traversable under volatile reads, so long
313 <     * as lookups check hash code and non-nullness of value before
314 <     * checking key equality.
315 <     *
316 <     * We use the top two bits of Node hash fields for control
217 <     * purposes -- they are available anyway because of addressing
218 <     * constraints.  As explained further below, these top bits are
219 <     * used as follows:
220 <     *  00 - Normal
221 <     *  01 - Locked
222 <     *  11 - Locked and may have a thread waiting for lock
223 <     *  10 - Node is a forwarding node
224 <     *
225 <     * The lower 30 bits of each Node's hash field contain a
226 <     * transformation of the key's hash code, except for forwarding
227 <     * nodes, for which the lower bits are zero (and so always have
228 <     * hash field == MOVED).
311 >     * (sun.misc.Unsafe) operations.
312 >     *
313 >     * We use the top (sign) bit of Node hash fields for control
314 >     * purposes -- it is available anyway because of addressing
315 >     * constraints.  Nodes with negative hash fields are specially
316 >     * handled or ignored in map methods.
317       *
318       * Insertion (via put or its variants) of the first node in an
319       * empty bin is performed by just CASing it to the bin.  This is
# Line 234 | Line 322 | public class ConcurrentHashMapV8<K, V>
322       * delete, and replace) require locks.  We do not want to waste
323       * the space required to associate a distinct lock object with
324       * each bin, so instead use the first node of a bin list itself as
325 <     * a lock. Blocking support for these locks relies on the builtin
326 <     * "synchronized" monitors.  However, we also need a tryLock
239 <     * construction, so we overlay these by using bits of the Node
240 <     * hash field for lock control (see above), and so normally use
241 <     * builtin monitors only for blocking and signalling using
242 <     * wait/notifyAll constructions. See Node.tryAwaitLock.
325 >     * a lock. Locking support for these locks relies on builtin
326 >     * "synchronized" monitors.
327       *
328       * Using the first node of a list as a lock does not by itself
329       * suffice though: When a node is locked, any update must first
330       * validate that it is still the first node after locking it, and
331       * retry if not. Because new nodes are always appended to lists,
332       * once a node is first in a bin, it remains first until deleted
333 <     * or the bin becomes invalidated (upon resizing).  However,
250 <     * operations that only conditionally update may inspect nodes
251 <     * until the point of update. This is a converse of sorts to the
252 <     * lazy locking technique described by Herlihy & Shavit.
333 >     * or the bin becomes invalidated (upon resizing).
334       *
335       * The main disadvantage of per-bin locks is that other update
336       * operations on other nodes in a bin list protected by the same
# Line 282 | Line 363 | public class ConcurrentHashMapV8<K, V>
363       * sometimes deviate significantly from uniform randomness.  This
364       * includes the case when N > (1<<30), so some keys MUST collide.
365       * Similarly for dumb or hostile usages in which multiple keys are
366 <     * designed to have identical hash codes. Also, although we guard
367 <     * against the worst effects of this (see method spread), sets of
368 <     * hashes may differ only in bits that do not impact their bin
369 <     * index for a given power-of-two mask.  So we use a secondary
370 <     * strategy that applies when the number of nodes in a bin exceeds
371 <     * a threshold, and at least one of the keys implements
291 <     * Comparable.  These TreeBins use a balanced tree to hold nodes
292 <     * (a specialized form of red-black trees), bounding search time
293 <     * to O(log N).  Each search step in a TreeBin is around twice as
366 >     * designed to have identical hash codes or ones that differs only
367 >     * in masked-out high bits. So we use a secondary strategy that
368 >     * applies when the number of nodes in a bin exceeds a
369 >     * threshold. These TreeBins use a balanced tree to hold nodes (a
370 >     * specialized form of red-black trees), bounding search time to
371 >     * O(log N).  Each search step in a TreeBin is at least twice as
372       * slow as in a regular list, but given that N cannot exceed
373       * (1<<64) (before running out of addresses) this bounds search
374       * steps, lock hold times, etc, to reasonable constants (roughly
# Line 301 | Line 379 | public class ConcurrentHashMapV8<K, V>
379       * iterators in the same way.
380       *
381       * The table is resized when occupancy exceeds a percentage
382 <     * threshold (nominally, 0.75, but see below).  Only a single
383 <     * thread performs the resize (using field "sizeCtl", to arrange
384 <     * exclusion), but the table otherwise remains usable for reads
385 <     * and updates. Resizing proceeds by transferring bins, one by
386 <     * one, from the table to the next table.  Because we are using
387 <     * power-of-two expansion, the elements from each bin must either
388 <     * stay at same index, or move with a power of two offset. We
389 <     * eliminate unnecessary node creation by catching cases where old
390 <     * nodes can be reused because their next fields won't change.  On
391 <     * average, only about one-sixth of them need cloning when a table
392 <     * doubles. The nodes they replace will be garbage collectable as
393 <     * soon as they are no longer referenced by any reader thread that
394 <     * may be in the midst of concurrently traversing table.  Upon
395 <     * transfer, the old table bin contains only a special forwarding
396 <     * node (with hash field "MOVED") that contains the next table as
397 <     * its key. On encountering a forwarding node, access and update
398 <     * operations restart, using the new table.
399 <     *
400 <     * Each bin transfer requires its bin lock. However, unlike other
401 <     * cases, a transfer can skip a bin if it fails to acquire its
402 <     * lock, and revisit it later (unless it is a TreeBin). Method
403 <     * rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
404 <     * have been skipped because of failure to acquire a lock, and
405 <     * blocks only if none are available (i.e., only very rarely).
406 <     * The transfer operation must also ensure that all accessible
407 <     * bins in both the old and new table are usable by any traversal.
408 <     * When there are no lock acquisition failures, this is arranged
409 <     * simply by proceeding from the last bin (table.length - 1) up
410 <     * towards the first.  Upon seeing a forwarding node, traversals
411 <     * (see class Iter) arrange to move to the new table
412 <     * without revisiting nodes.  However, when any node is skipped
413 <     * during a transfer, all earlier table bins may have become
414 <     * visible, so are initialized with a reverse-forwarding node back
415 <     * to the old table until the new ones are established. (This
416 <     * sometimes requires transiently locking a forwarding node, which
417 <     * is possible under the above encoding.) These more expensive
418 <     * mechanics trigger only when necessary.
382 >     * threshold (nominally, 0.75, but see below).  Any thread
383 >     * noticing an overfull bin may assist in resizing after the
384 >     * initiating thread allocates and sets up the replacement
385 >     * array. However, rather than stalling, these other threads may
386 >     * proceed with insertions etc.  The use of TreeBins shields us
387 >     * from the worst case effects of overfilling while resizes are in
388 >     * progress.  Resizing proceeds by transferring bins, one by one,
389 >     * from the table to the next table. To enable concurrency, the
390 >     * next table must be (incrementally) prefilled with place-holders
391 >     * serving as reverse forwarders to the old table.  Because we are
392 >     * using power-of-two expansion, the elements from each bin must
393 >     * either stay at same index, or move with a power of two
394 >     * offset. We eliminate unnecessary node creation by catching
395 >     * cases where old nodes can be reused because their next fields
396 >     * won't change.  On average, only about one-sixth of them need
397 >     * cloning when a table doubles. The nodes they replace will be
398 >     * garbage collectable as soon as they are no longer referenced by
399 >     * any reader thread that may be in the midst of concurrently
400 >     * traversing table.  Upon transfer, the old table bin contains
401 >     * only a special forwarding node (with hash field "MOVED") that
402 >     * contains the next table as its key. On encountering a
403 >     * forwarding node, access and update operations restart, using
404 >     * the new table.
405 >     *
406 >     * Each bin transfer requires its bin lock, which can stall
407 >     * waiting for locks while resizing. However, because other
408 >     * threads can join in and help resize rather than contend for
409 >     * locks, average aggregate waits become shorter as resizing
410 >     * progresses.  The transfer operation must also ensure that all
411 >     * accessible bins in both the old and new table are usable by any
412 >     * traversal.  This is arranged by proceeding from the last bin
413 >     * (table.length - 1) up towards the first.  Upon seeing a
414 >     * forwarding node, traversals (see class Traverser) arrange to
415 >     * move to the new table without revisiting nodes.  However, to
416 >     * ensure that no intervening nodes are skipped, bin splitting can
417 >     * only begin after the associated reverse-forwarders are in
418 >     * place.
419       *
420       * The traversal scheme also applies to partial traversals of
421       * ranges of bins (via an alternate Traverser constructor)
# Line 352 | Line 430 | public class ConcurrentHashMapV8<K, V>
430       * These cases attempt to override the initial capacity settings,
431       * but harmlessly fail to take effect in cases of races.
432       *
433 <     * The element count is maintained using a LongAdder, which avoids
434 <     * contention on updates but can encounter cache thrashing if read
435 <     * too frequently during concurrent access. To avoid reading so
436 <     * often, resizing is attempted either when a bin lock is
437 <     * contended, or upon adding to a bin already holding two or more
438 <     * nodes (checked before adding in the xIfAbsent methods, after
439 <     * adding in others). Under uniform hash distributions, the
440 <     * probability of this occurring at threshold is around 13%,
441 <     * meaning that only about 1 in 8 puts check threshold (and after
442 <     * resizing, many fewer do so). But this approximation has high
443 <     * variance for small table sizes, so we check on any collision
444 <     * for sizes <= 64. The bulk putAll operation further reduces
445 <     * contention by only committing count updates upon these size
446 <     * checks.
433 >     * The element count is maintained using a specialization of
434 >     * LongAdder. We need to incorporate a specialization rather than
435 >     * just use a LongAdder in order to access implicit
436 >     * contention-sensing that leads to creation of multiple
437 >     * CounterCells.  The counter mechanics avoid contention on
438 >     * updates but can encounter cache thrashing if read too
439 >     * frequently during concurrent access. To avoid reading so often,
440 >     * resizing under contention is attempted only upon adding to a
441 >     * bin already holding two or more nodes. Under uniform hash
442 >     * distributions, the probability of this occurring at threshold
443 >     * is around 13%, meaning that only about 1 in 8 puts check
444 >     * threshold (and after resizing, many fewer do so).
445 >     *
446 >     * TreeBins use a special form of comparison for search and
447 >     * related operations (which is the main reason we cannot use
448 >     * existing collections such as TreeMaps). TreeBins contain
449 >     * Comparable elements, but may contain others, as well as
450 >     * elements that are Comparable but not necessarily Comparable for
451 >     * the same T, so we cannot invoke compareTo among them. To handle
452 >     * this, the tree is ordered primarily by hash value, then by
453 >     * Comparable.compareTo order if applicable.  On lookup at a node,
454 >     * if elements are not comparable or compare as 0 then both left
455 >     * and right children may need to be searched in the case of tied
456 >     * hash values. (This corresponds to the full list search that
457 >     * would be necessary if all elements were non-Comparable and had
458 >     * tied hashes.) On insertion, to keep a total ordering (or as
459 >     * close as is required here) across rebalancings, we compare
460 >     * classes and identityHashCodes as tie-breakers. The red-black
461 >     * balancing code is updated from pre-jdk-collections
462 >     * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
463 >     * based in turn on Cormen, Leiserson, and Rivest "Introduction to
464 >     * Algorithms" (CLR).
465 >     *
466 >     * TreeBins also require an additional locking mechanism.  While
467 >     * list traversal is always possible by readers even during
468 >     * updates, tree traversal is not, mainly because of tree-rotations
469 >     * that may change the root node and/or its linkages.  TreeBins
470 >     * include a simple read-write lock mechanism parasitic on the
471 >     * main bin-synchronization strategy: Structural adjustments
472 >     * associated with an insertion or removal are already bin-locked
473 >     * (and so cannot conflict with other writers) but must wait for
474 >     * ongoing readers to finish. Since there can be only one such
475 >     * waiter, we use a simple scheme using a single "waiter" field to
476 >     * block writers.  However, readers need never block.  If the root
477 >     * lock is held, they proceed along the slow traversal path (via
478 >     * next-pointers) until the lock becomes available or the list is
479 >     * exhausted, whichever comes first. These cases are not fast, but
480 >     * maximize aggregate expected throughput.
481       *
482       * Maintaining API and serialization compatibility with previous
483       * versions of this class introduces several oddities. Mainly: We
# Line 375 | Line 487 | public class ConcurrentHashMapV8<K, V>
487       * time that we can guarantee to honor it.) We also declare an
488       * unused "Segment" class that is instantiated in minimal form
489       * only when serializing.
490 +     *
491 +     * Also, solely for compatibility with previous versions of this
492 +     * class, it extends AbstractMap, even though all of its methods
493 +     * are overridden, so it is just useless baggage.
494 +     *
495 +     * This file is organized to make things a little easier to follow
496 +     * while reading than they might otherwise: First the main static
497 +     * declarations and utilities, then fields, then main public
498 +     * methods (with a few factorings of multiple public methods into
499 +     * internal ones), then sizing methods, trees, traversers, and
500 +     * bulk operations.
501       */
502  
503      /* ---------------- Constants -------------- */
# Line 416 | Line 539 | public class ConcurrentHashMapV8<K, V>
539      private static final float LOAD_FACTOR = 0.75f;
540  
541      /**
419     * The buffer size for skipped bins during transfers. The
420     * value is arbitrary but should be large enough to avoid
421     * most locking stalls during resizes.
422     */
423    private static final int TRANSFER_BUFFER_SIZE = 32;
424
425    /**
542       * The bin count threshold for using a tree rather than list for a
543 <     * bin.  The value reflects the approximate break-even point for
544 <     * using tree-based operations.
545 <     */
546 <    private static final int TREE_THRESHOLD = 8;
547 <
432 <    /*
433 <     * Encodings for special uses of Node hash fields. See above for
434 <     * explanation.
543 >     * bin.  Bins are converted to trees when adding an element to a
544 >     * bin with at least this many nodes. The value must be greater
545 >     * than 2, and should be at least 8 to mesh with assumptions in
546 >     * tree removal about conversion back to plain bins upon
547 >     * shrinkage.
548       */
549 <    static final int MOVED     = 0x80000000; // hash field for forwarding nodes
437 <    static final int LOCKED    = 0x40000000; // set/tested only as a bit
438 <    static final int WAITING   = 0xc0000000; // both bits set/tested together
439 <    static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
440 <
441 <    /* ---------------- Fields -------------- */
549 >    static final int TREEIFY_THRESHOLD = 8;
550  
551      /**
552 <     * The array of bins. Lazily initialized upon first insertion.
553 <     * Size is always a power of two. Accessed directly by iterators.
552 >     * The bin count threshold for untreeifying a (split) bin during a
553 >     * resize operation. Should be less than TREEIFY_THRESHOLD, and at
554 >     * most 6 to mesh with shrinkage detection under removal.
555       */
556 <    transient volatile Node[] table;
556 >    static final int UNTREEIFY_THRESHOLD = 6;
557  
558      /**
559 <     * The counter maintaining number of elements.
559 >     * The smallest table capacity for which bins may be treeified.
560 >     * (Otherwise the table is resized if too many nodes in a bin.)
561 >     * The value should be at least 4 * TREEIFY_THRESHOLD to avoid
562 >     * conflicts between resizing and treeification thresholds.
563       */
564 <    private transient final LongAdder counter;
564 >    static final int MIN_TREEIFY_CAPACITY = 64;
565  
566      /**
567 <     * Table initialization and resizing control.  When negative, the
568 <     * table is being initialized or resized. Otherwise, when table is
569 <     * null, holds the initial table size to use upon creation, or 0
570 <     * for default. After initialization, holds the next element count
571 <     * value upon which to resize the table.
567 >     * Minimum number of rebinnings per transfer step. Ranges are
568 >     * subdivided to allow multiple resizer threads.  This value
569 >     * serves as a lower bound to avoid resizers encountering
570 >     * excessive memory contention.  The value should be at least
571 >     * DEFAULT_CAPACITY.
572       */
573 <    private transient volatile int sizeCtl;
462 <
463 <    // views
464 <    private transient KeySet<K,V> keySet;
465 <    private transient Values<K,V> values;
466 <    private transient EntrySet<K,V> entrySet;
467 <
468 <    /** For serialization compatibility. Null unless serialized; see below */
469 <    private Segment<K,V>[] segments;
470 <
471 <    /* ---------------- Table element access -------------- */
573 >    private static final int MIN_TRANSFER_STRIDE = 16;
574  
575      /*
576 <     * Volatile access methods are used for table elements as well as
475 <     * elements of in-progress next table while resizing.  Uses are
476 <     * null checked by callers, and implicitly bounds-checked, relying
477 <     * on the invariants that tab arrays have non-zero size, and all
478 <     * indices are masked with (tab.length - 1) which is never
479 <     * negative and always less than length. Note that, to be correct
480 <     * wrt arbitrary concurrency errors by users, bounds checks must
481 <     * operate on local variables, which accounts for some odd-looking
482 <     * inline assignments below.
576 >     * Encodings for Node hash fields. See above for explanation.
577       */
578 <
579 <    static final Node tabAt(Node[] tab, int i) { // used by Iter
580 <        return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
581 <    }
582 <
583 <    private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
584 <        return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
585 <    }
586 <
587 <    private static final void setTabAt(Node[] tab, int i, Node v) {
588 <        UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
589 <    }
578 >    static final int MOVED     = -1; // hash for forwarding nodes
579 >    static final int TREEBIN   = -2; // hash for roots of trees
580 >    static final int RESERVED  = -3; // hash for transient reservations
581 >    static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
582 >
583 >    /** Number of CPUS, to place bounds on some sizings */
584 >    static final int NCPU = Runtime.getRuntime().availableProcessors();
585 >
586 >    /** For serialization compatibility. */
587 >    private static final ObjectStreamField[] serialPersistentFields = {
588 >        new ObjectStreamField("segments", Segment[].class),
589 >        new ObjectStreamField("segmentMask", Integer.TYPE),
590 >        new ObjectStreamField("segmentShift", Integer.TYPE)
591 >    };
592  
593      /* ---------------- Nodes -------------- */
594  
595      /**
596 <     * Key-value entry. Note that this is never exported out as a
597 <     * user-visible Map.Entry (see MapEntry below). Nodes with a hash
598 <     * field of MOVED are special, and do not contain user keys or
599 <     * values.  Otherwise, keys are never null, and null val fields
600 <     * indicate that a node is in the process of being deleted or
601 <     * created. For purposes of read-only access, a key may be read
602 <     * before a val, but can only be used after checking val to be
603 <     * non-null.
604 <     */
605 <    static class Node {
606 <        volatile int hash;
607 <        final Object key;
512 <        volatile Object val;
513 <        volatile Node next;
596 >     * Key-value entry.  This class is never exported out as a
597 >     * user-mutable Map.Entry (i.e., one supporting setValue; see
598 >     * MapEntry below), but can be used for read-only traversals used
599 >     * in bulk tasks.  Subclasses of Node with a negative hash field
600 >     * are special, and contain null keys and values (but are never
601 >     * exported).  Otherwise, keys and vals are never null.
602 >     */
603 >    static class Node<K,V> implements Map.Entry<K,V> {
604 >        final int hash;
605 >        final K key;
606 >        volatile V val;
607 >        volatile Node<K,V> next;
608  
609 <        Node(int hash, Object key, Object val, Node next) {
609 >        Node(int hash, K key, V val, Node<K,V> next) {
610              this.hash = hash;
611              this.key = key;
612              this.val = val;
613              this.next = next;
614          }
615  
616 <        /** CompareAndSet the hash field */
617 <        final boolean casHash(int cmp, int val) {
618 <            return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
619 <        }
620 <
621 <        /** The number of spins before blocking for a lock */
528 <        static final int MAX_SPINS =
529 <            Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
530 <
531 <        /**
532 <         * Spins a while if LOCKED bit set and this node is the first
533 <         * of its bin, and then sets WAITING bits on hash field and
534 <         * blocks (once) if they are still set.  It is OK for this
535 <         * method to return even if lock is not available upon exit,
536 <         * which enables these simple single-wait mechanics.
537 <         *
538 <         * The corresponding signalling operation is performed within
539 <         * callers: Upon detecting that WAITING has been set when
540 <         * unlocking lock (via a failed CAS from non-waiting LOCKED
541 <         * state), unlockers acquire the sync lock and perform a
542 <         * notifyAll.
543 <         *
544 <         * The initial sanity check on tab and bounds is not currently
545 <         * necessary in the only usages of this method, but enables
546 <         * use in other future contexts.
547 <         */
548 <        final void tryAwaitLock(Node[] tab, int i) {
549 <            if (tab != null && i >= 0 && i < tab.length) { // sanity check
550 <                int r = ThreadLocalRandom.current().nextInt(); // randomize spins
551 <                int spins = MAX_SPINS, h;
552 <                while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
553 <                    if (spins >= 0) {
554 <                        r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
555 <                        if (r >= 0 && --spins == 0)
556 <                            Thread.yield();  // yield before block
557 <                    }
558 <                    else if (casHash(h, h | WAITING)) {
559 <                        synchronized (this) {
560 <                            if (tabAt(tab, i) == this &&
561 <                                (hash & WAITING) == WAITING) {
562 <                                try {
563 <                                    wait();
564 <                                } catch (InterruptedException ie) {
565 <                                    Thread.currentThread().interrupt();
566 <                                }
567 <                            }
568 <                            else
569 <                                notifyAll(); // possibly won race vs signaller
570 <                        }
571 <                        break;
572 <                    }
573 <                }
574 <            }
575 <        }
576 <
577 <        // Unsafe mechanics for casHash
578 <        private static final sun.misc.Unsafe UNSAFE;
579 <        private static final long hashOffset;
580 <
581 <        static {
582 <            try {
583 <                UNSAFE = getUnsafe();
584 <                Class<?> k = Node.class;
585 <                hashOffset = UNSAFE.objectFieldOffset
586 <                    (k.getDeclaredField("hash"));
587 <            } catch (Exception e) {
588 <                throw new Error(e);
589 <            }
590 <        }
591 <    }
592 <
593 <    /* ---------------- TreeBins -------------- */
594 <
595 <    /**
596 <     * Nodes for use in TreeBins
597 <     */
598 <    static final class TreeNode extends Node {
599 <        TreeNode parent;  // red-black tree links
600 <        TreeNode left;
601 <        TreeNode right;
602 <        TreeNode prev;    // needed to unlink next upon deletion
603 <        boolean red;
604 <
605 <        TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
606 <            super(hash, key, val, next);
607 <            this.parent = parent;
608 <        }
609 <    }
610 <
611 <    /**
612 <     * A specialized form of red-black tree for use in bins
613 <     * whose size exceeds a threshold.
614 <     *
615 <     * TreeBins use a special form of comparison for search and
616 <     * related operations (which is the main reason we cannot use
617 <     * existing collections such as TreeMaps). TreeBins contain
618 <     * Comparable elements, but may contain others, as well as
619 <     * elements that are Comparable but not necessarily Comparable<T>
620 <     * for the same T, so we cannot invoke compareTo among them. To
621 <     * handle this, the tree is ordered primarily by hash value, then
622 <     * by getClass().getName() order, and then by Comparator order
623 <     * among elements of the same class.  On lookup at a node, if
624 <     * elements are not comparable or compare as 0, both left and
625 <     * right children may need to be searched in the case of tied hash
626 <     * values. (This corresponds to the full list search that would be
627 <     * necessary if all elements were non-Comparable and had tied
628 <     * hashes.)  The red-black balancing code is updated from
629 <     * pre-jdk-collections
630 <     * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
631 <     * based in turn on Cormen, Leiserson, and Rivest "Introduction to
632 <     * Algorithms" (CLR).
633 <     *
634 <     * TreeBins also maintain a separate locking discipline than
635 <     * regular bins. Because they are forwarded via special MOVED
636 <     * nodes at bin heads (which can never change once established),
637 <     * we cannot use those nodes as locks. Instead, TreeBin
638 <     * extends AbstractQueuedSynchronizer to support a simple form of
639 <     * read-write lock. For update operations and table validation,
640 <     * the exclusive form of lock behaves in the same way as bin-head
641 <     * locks. However, lookups use shared read-lock mechanics to allow
642 <     * multiple readers in the absence of writers.  Additionally,
643 <     * these lookups do not ever block: While the lock is not
644 <     * available, they proceed along the slow traversal path (via
645 <     * next-pointers) until the lock becomes available or the list is
646 <     * exhausted, whichever comes first. (These cases are not fast,
647 <     * but maximize aggregate expected throughput.)  The AQS mechanics
648 <     * for doing this are straightforward.  The lock state is held as
649 <     * AQS getState().  Read counts are negative; the write count (1)
650 <     * is positive.  There are no signalling preferences among readers
651 <     * and writers. Since we don't need to export full Lock API, we
652 <     * just override the minimal AQS methods and use them directly.
653 <     */
654 <    static final class TreeBin extends AbstractQueuedSynchronizer {
655 <        private static final long serialVersionUID = 2249069246763182397L;
656 <        transient TreeNode root;  // root of tree
657 <        transient TreeNode first; // head of next-pointer list
658 <
659 <        /* AQS overrides */
660 <        public final boolean isHeldExclusively() { return getState() > 0; }
661 <        public final boolean tryAcquire(int ignore) {
662 <            if (compareAndSetState(0, 1)) {
663 <                setExclusiveOwnerThread(Thread.currentThread());
664 <                return true;
665 <            }
666 <            return false;
667 <        }
668 <        public final boolean tryRelease(int ignore) {
669 <            setExclusiveOwnerThread(null);
670 <            setState(0);
671 <            return true;
672 <        }
673 <        public final int tryAcquireShared(int ignore) {
674 <            for (int c;;) {
675 <                if ((c = getState()) > 0)
676 <                    return -1;
677 <                if (compareAndSetState(c, c -1))
678 <                    return 1;
679 <            }
680 <        }
681 <        public final boolean tryReleaseShared(int ignore) {
682 <            int c;
683 <            do {} while (!compareAndSetState(c = getState(), c + 1));
684 <            return c == -1;
685 <        }
686 <
687 <        /** From CLR */
688 <        private void rotateLeft(TreeNode p) {
689 <            if (p != null) {
690 <                TreeNode r = p.right, pp, rl;
691 <                if ((rl = p.right = r.left) != null)
692 <                    rl.parent = p;
693 <                if ((pp = r.parent = p.parent) == null)
694 <                    root = r;
695 <                else if (pp.left == p)
696 <                    pp.left = r;
697 <                else
698 <                    pp.right = r;
699 <                r.left = p;
700 <                p.parent = r;
701 <            }
702 <        }
703 <
704 <        /** From CLR */
705 <        private void rotateRight(TreeNode p) {
706 <            if (p != null) {
707 <                TreeNode l = p.left, pp, lr;
708 <                if ((lr = p.left = l.right) != null)
709 <                    lr.parent = p;
710 <                if ((pp = l.parent = p.parent) == null)
711 <                    root = l;
712 <                else if (pp.right == p)
713 <                    pp.right = l;
714 <                else
715 <                    pp.left = l;
716 <                l.right = p;
717 <                p.parent = l;
718 <            }
719 <        }
720 <
721 <        /**
722 <         * Returns the TreeNode (or null if not found) for the given key
723 <         * starting at given root.
724 <         */
725 <        @SuppressWarnings("unchecked") final TreeNode getTreeNode
726 <            (int h, Object k, TreeNode p) {
727 <            Class<?> c = k.getClass();
728 <            while (p != null) {
729 <                int dir, ph;  Object pk; Class<?> pc;
730 <                if ((ph = p.hash) == h) {
731 <                    if ((pk = p.key) == k || k.equals(pk))
732 <                        return p;
733 <                    if (c != (pc = pk.getClass()) ||
734 <                        !(k instanceof Comparable) ||
735 <                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
736 <                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
737 <                        TreeNode r = null, s = null, pl, pr;
738 <                        if (dir >= 0) {
739 <                            if ((pl = p.left) != null && h <= pl.hash)
740 <                                s = pl;
741 <                        }
742 <                        else if ((pr = p.right) != null && h >= pr.hash)
743 <                            s = pr;
744 <                        if (s != null && (r = getTreeNode(h, k, s)) != null)
745 <                            return r;
746 <                    }
747 <                }
748 <                else
749 <                    dir = (h < ph) ? -1 : 1;
750 <                p = (dir > 0) ? p.right : p.left;
751 <            }
752 <            return null;
616 >        public final K getKey()       { return key; }
617 >        public final V getValue()     { return val; }
618 >        public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
619 >        public final String toString(){ return key + "=" + val; }
620 >        public final V setValue(V value) {
621 >            throw new UnsupportedOperationException();
622          }
623  
624 <        /**
625 <         * Wrapper for getTreeNode used by CHM.get. Tries to obtain
626 <         * read-lock to call getTreeNode, but during failure to get
627 <         * lock, searches along next links.
628 <         */
629 <        final Object getValue(int h, Object k) {
630 <            Node r = null;
762 <            int c = getState(); // Must read lock state first
763 <            for (Node e = first; e != null; e = e.next) {
764 <                if (c <= 0 && compareAndSetState(c, c - 1)) {
765 <                    try {
766 <                        r = getTreeNode(h, k, root);
767 <                    } finally {
768 <                        releaseShared(0);
769 <                    }
770 <                    break;
771 <                }
772 <                else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
773 <                    r = e;
774 <                    break;
775 <                }
776 <                else
777 <                    c = getState();
778 <            }
779 <            return r == null ? null : r.val;
624 >        public final boolean equals(Object o) {
625 >            Object k, v, u; Map.Entry<?,?> e;
626 >            return ((o instanceof Map.Entry) &&
627 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
628 >                    (v = e.getValue()) != null &&
629 >                    (k == key || k.equals(key)) &&
630 >                    (v == (u = val) || v.equals(u)));
631          }
632  
633          /**
634 <         * Finds or adds a node.
784 <         * @return null if added
634 >         * Virtualized support for map.get(); overridden in subclasses.
635           */
636 <        @SuppressWarnings("unchecked") final TreeNode putTreeNode
637 <            (int h, Object k, Object v) {
638 <            Class<?> c = k.getClass();
639 <            TreeNode pp = root, p = null;
640 <            int dir = 0;
641 <            while (pp != null) { // find existing node or leaf to insert at
642 <                int ph;  Object pk; Class<?> pc;
643 <                p = pp;
644 <                if ((ph = p.hash) == h) {
795 <                    if ((pk = p.key) == k || k.equals(pk))
796 <                        return p;
797 <                    if (c != (pc = pk.getClass()) ||
798 <                        !(k instanceof Comparable) ||
799 <                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
800 <                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
801 <                        TreeNode r = null, s = null, pl, pr;
802 <                        if (dir >= 0) {
803 <                            if ((pl = p.left) != null && h <= pl.hash)
804 <                                s = pl;
805 <                        }
806 <                        else if ((pr = p.right) != null && h >= pr.hash)
807 <                            s = pr;
808 <                        if (s != null && (r = getTreeNode(h, k, s)) != null)
809 <                            return r;
810 <                    }
811 <                }
812 <                else
813 <                    dir = (h < ph) ? -1 : 1;
814 <                pp = (dir > 0) ? p.right : p.left;
815 <            }
816 <
817 <            TreeNode f = first;
818 <            TreeNode x = first = new TreeNode(h, k, v, f, p);
819 <            if (p == null)
820 <                root = x;
821 <            else { // attach and rebalance; adapted from CLR
822 <                TreeNode xp, xpp;
823 <                if (f != null)
824 <                    f.prev = x;
825 <                if (dir <= 0)
826 <                    p.left = x;
827 <                else
828 <                    p.right = x;
829 <                x.red = true;
830 <                while (x != null && (xp = x.parent) != null && xp.red &&
831 <                       (xpp = xp.parent) != null) {
832 <                    TreeNode xppl = xpp.left;
833 <                    if (xp == xppl) {
834 <                        TreeNode y = xpp.right;
835 <                        if (y != null && y.red) {
836 <                            y.red = false;
837 <                            xp.red = false;
838 <                            xpp.red = true;
839 <                            x = xpp;
840 <                        }
841 <                        else {
842 <                            if (x == xp.right) {
843 <                                rotateLeft(x = xp);
844 <                                xpp = (xp = x.parent) == null ? null : xp.parent;
845 <                            }
846 <                            if (xp != null) {
847 <                                xp.red = false;
848 <                                if (xpp != null) {
849 <                                    xpp.red = true;
850 <                                    rotateRight(xpp);
851 <                                }
852 <                            }
853 <                        }
854 <                    }
855 <                    else {
856 <                        TreeNode y = xppl;
857 <                        if (y != null && y.red) {
858 <                            y.red = false;
859 <                            xp.red = false;
860 <                            xpp.red = true;
861 <                            x = xpp;
862 <                        }
863 <                        else {
864 <                            if (x == xp.left) {
865 <                                rotateRight(x = xp);
866 <                                xpp = (xp = x.parent) == null ? null : xp.parent;
867 <                            }
868 <                            if (xp != null) {
869 <                                xp.red = false;
870 <                                if (xpp != null) {
871 <                                    xpp.red = true;
872 <                                    rotateLeft(xpp);
873 <                                }
874 <                            }
875 <                        }
876 <                    }
877 <                }
878 <                TreeNode r = root;
879 <                if (r != null && r.red)
880 <                    r.red = false;
636 >        Node<K,V> find(int h, Object k) {
637 >            Node<K,V> e = this;
638 >            if (k != null) {
639 >                do {
640 >                    K ek;
641 >                    if (e.hash == h &&
642 >                        ((ek = e.key) == k || (ek != null && k.equals(ek))))
643 >                        return e;
644 >                } while ((e = e.next) != null);
645              }
646              return null;
647          }
884
885        /**
886         * Removes the given node, that must be present before this
887         * call.  This is messier than typical red-black deletion code
888         * because we cannot swap the contents of an interior node
889         * with a leaf successor that is pinned by "next" pointers
890         * that are accessible independently of lock. So instead we
891         * swap the tree linkages.
892         */
893        final void deleteTreeNode(TreeNode p) {
894            TreeNode next = (TreeNode)p.next; // unlink traversal pointers
895            TreeNode pred = p.prev;
896            if (pred == null)
897                first = next;
898            else
899                pred.next = next;
900            if (next != null)
901                next.prev = pred;
902            TreeNode replacement;
903            TreeNode pl = p.left;
904            TreeNode pr = p.right;
905            if (pl != null && pr != null) {
906                TreeNode s = pr, sl;
907                while ((sl = s.left) != null) // find successor
908                    s = sl;
909                boolean c = s.red; s.red = p.red; p.red = c; // swap colors
910                TreeNode sr = s.right;
911                TreeNode pp = p.parent;
912                if (s == pr) { // p was s's direct parent
913                    p.parent = s;
914                    s.right = p;
915                }
916                else {
917                    TreeNode sp = s.parent;
918                    if ((p.parent = sp) != null) {
919                        if (s == sp.left)
920                            sp.left = p;
921                        else
922                            sp.right = p;
923                    }
924                    if ((s.right = pr) != null)
925                        pr.parent = s;
926                }
927                p.left = null;
928                if ((p.right = sr) != null)
929                    sr.parent = p;
930                if ((s.left = pl) != null)
931                    pl.parent = s;
932                if ((s.parent = pp) == null)
933                    root = s;
934                else if (p == pp.left)
935                    pp.left = s;
936                else
937                    pp.right = s;
938                replacement = sr;
939            }
940            else
941                replacement = (pl != null) ? pl : pr;
942            TreeNode pp = p.parent;
943            if (replacement == null) {
944                if (pp == null) {
945                    root = null;
946                    return;
947                }
948                replacement = p;
949            }
950            else {
951                replacement.parent = pp;
952                if (pp == null)
953                    root = replacement;
954                else if (p == pp.left)
955                    pp.left = replacement;
956                else
957                    pp.right = replacement;
958                p.left = p.right = p.parent = null;
959            }
960            if (!p.red) { // rebalance, from CLR
961                TreeNode x = replacement;
962                while (x != null) {
963                    TreeNode xp, xpl;
964                    if (x.red || (xp = x.parent) == null) {
965                        x.red = false;
966                        break;
967                    }
968                    if (x == (xpl = xp.left)) {
969                        TreeNode sib = xp.right;
970                        if (sib != null && sib.red) {
971                            sib.red = false;
972                            xp.red = true;
973                            rotateLeft(xp);
974                            sib = (xp = x.parent) == null ? null : xp.right;
975                        }
976                        if (sib == null)
977                            x = xp;
978                        else {
979                            TreeNode sl = sib.left, sr = sib.right;
980                            if ((sr == null || !sr.red) &&
981                                (sl == null || !sl.red)) {
982                                sib.red = true;
983                                x = xp;
984                            }
985                            else {
986                                if (sr == null || !sr.red) {
987                                    if (sl != null)
988                                        sl.red = false;
989                                    sib.red = true;
990                                    rotateRight(sib);
991                                    sib = (xp = x.parent) == null ? null : xp.right;
992                                }
993                                if (sib != null) {
994                                    sib.red = (xp == null) ? false : xp.red;
995                                    if ((sr = sib.right) != null)
996                                        sr.red = false;
997                                }
998                                if (xp != null) {
999                                    xp.red = false;
1000                                    rotateLeft(xp);
1001                                }
1002                                x = root;
1003                            }
1004                        }
1005                    }
1006                    else { // symmetric
1007                        TreeNode sib = xpl;
1008                        if (sib != null && sib.red) {
1009                            sib.red = false;
1010                            xp.red = true;
1011                            rotateRight(xp);
1012                            sib = (xp = x.parent) == null ? null : xp.left;
1013                        }
1014                        if (sib == null)
1015                            x = xp;
1016                        else {
1017                            TreeNode sl = sib.left, sr = sib.right;
1018                            if ((sl == null || !sl.red) &&
1019                                (sr == null || !sr.red)) {
1020                                sib.red = true;
1021                                x = xp;
1022                            }
1023                            else {
1024                                if (sl == null || !sl.red) {
1025                                    if (sr != null)
1026                                        sr.red = false;
1027                                    sib.red = true;
1028                                    rotateLeft(sib);
1029                                    sib = (xp = x.parent) == null ? null : xp.left;
1030                                }
1031                                if (sib != null) {
1032                                    sib.red = (xp == null) ? false : xp.red;
1033                                    if ((sl = sib.left) != null)
1034                                        sl.red = false;
1035                                }
1036                                if (xp != null) {
1037                                    xp.red = false;
1038                                    rotateRight(xp);
1039                                }
1040                                x = root;
1041                            }
1042                        }
1043                    }
1044                }
1045            }
1046            if (p == replacement && (pp = p.parent) != null) {
1047                if (p == pp.left) // detach pointers
1048                    pp.left = null;
1049                else if (p == pp.right)
1050                    pp.right = null;
1051                p.parent = null;
1052            }
1053        }
648      }
649  
650 <    /* ---------------- Collision reduction methods -------------- */
650 >    /* ---------------- Static utilities -------------- */
651  
652      /**
653 <     * Spreads higher bits to lower, and also forces top 2 bits to 0.
654 <     * Because the table uses power-of-two masking, sets of hashes
655 <     * that vary only in bits above the current mask will always
656 <     * collide. (Among known examples are sets of Float keys holding
657 <     * consecutive whole numbers in small tables.)  To counter this,
658 <     * we apply a transform that spreads the impact of higher bits
653 >     * Spreads (XORs) higher bits of hash to lower and also forces top
654 >     * bit to 0. Because the table uses power-of-two masking, sets of
655 >     * hashes that vary only in bits above the current mask will
656 >     * always collide. (Among known examples are sets of Float keys
657 >     * holding consecutive whole numbers in small tables.)  So we
658 >     * apply a transform that spreads the impact of higher bits
659       * downward. There is a tradeoff between speed, utility, and
660       * quality of bit-spreading. Because many common sets of hashes
661 <     * are already reasonably distributed across bits (so don't benefit
662 <     * from spreading), and because we use trees to handle large sets
663 <     * of collisions in bins, we don't need excessively high quality.
664 <     */
665 <    private static final int spread(int h) {
666 <        h ^= (h >>> 18) ^ (h >>> 12);
1073 <        return (h ^ (h >>> 10)) & HASH_BITS;
1074 <    }
1075 <
1076 <    /**
1077 <     * Replaces a list bin with a tree bin. Call only when locked.
1078 <     * Fails to replace if the given key is non-comparable or table
1079 <     * is, or needs, resizing.
661 >     * are already reasonably distributed (so don't benefit from
662 >     * spreading), and because we use trees to handle large sets of
663 >     * collisions in bins, we just XOR some shifted bits in the
664 >     * cheapest possible way to reduce systematic lossage, as well as
665 >     * to incorporate impact of the highest bits that would otherwise
666 >     * never be used in index calculations because of table bounds.
667       */
668 <    private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
669 <        if ((key instanceof Comparable) &&
1083 <            (tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
1084 <            TreeBin t = new TreeBin();
1085 <            for (Node e = tabAt(tab, index); e != null; e = e.next)
1086 <                t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
1087 <            setTabAt(tab, index, new Node(MOVED, t, null, null));
1088 <        }
1089 <    }
1090 <
1091 <    /* ---------------- Internal access and update methods -------------- */
1092 <
1093 <    /** Implementation for get and containsKey */
1094 <    private final Object internalGet(Object k) {
1095 <        int h = spread(k.hashCode());
1096 <        retry: for (Node[] tab = table; tab != null;) {
1097 <            Node e, p; Object ek, ev; int eh;      // locals to read fields once
1098 <            for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1099 <                if ((eh = e.hash) == MOVED) {
1100 <                    if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1101 <                        return ((TreeBin)ek).getValue(h, k);
1102 <                    else {                        // restart with new table
1103 <                        tab = (Node[])ek;
1104 <                        continue retry;
1105 <                    }
1106 <                }
1107 <                else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1108 <                         ((ek = e.key) == k || k.equals(ek)))
1109 <                    return ev;
1110 <            }
1111 <            break;
1112 <        }
1113 <        return null;
1114 <    }
1115 <
1116 <    /**
1117 <     * Implementation for the four public remove/replace methods:
1118 <     * Replaces node value with v, conditional upon match of cv if
1119 <     * non-null.  If resulting value is null, delete.
1120 <     */
1121 <    private final Object internalReplace(Object k, Object v, Object cv) {
1122 <        int h = spread(k.hashCode());
1123 <        Object oldVal = null;
1124 <        for (Node[] tab = table;;) {
1125 <            Node f; int i, fh; Object fk;
1126 <            if (tab == null ||
1127 <                (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1128 <                break;
1129 <            else if ((fh = f.hash) == MOVED) {
1130 <                if ((fk = f.key) instanceof TreeBin) {
1131 <                    TreeBin t = (TreeBin)fk;
1132 <                    boolean validated = false;
1133 <                    boolean deleted = false;
1134 <                    t.acquire(0);
1135 <                    try {
1136 <                        if (tabAt(tab, i) == f) {
1137 <                            validated = true;
1138 <                            TreeNode p = t.getTreeNode(h, k, t.root);
1139 <                            if (p != null) {
1140 <                                Object pv = p.val;
1141 <                                if (cv == null || cv == pv || cv.equals(pv)) {
1142 <                                    oldVal = pv;
1143 <                                    if ((p.val = v) == null) {
1144 <                                        deleted = true;
1145 <                                        t.deleteTreeNode(p);
1146 <                                    }
1147 <                                }
1148 <                            }
1149 <                        }
1150 <                    } finally {
1151 <                        t.release(0);
1152 <                    }
1153 <                    if (validated) {
1154 <                        if (deleted)
1155 <                            counter.add(-1L);
1156 <                        break;
1157 <                    }
1158 <                }
1159 <                else
1160 <                    tab = (Node[])fk;
1161 <            }
1162 <            else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1163 <                break;                          // rules out possible existence
1164 <            else if ((fh & LOCKED) != 0) {
1165 <                checkForResize();               // try resizing if can't get lock
1166 <                f.tryAwaitLock(tab, i);
1167 <            }
1168 <            else if (f.casHash(fh, fh | LOCKED)) {
1169 <                boolean validated = false;
1170 <                boolean deleted = false;
1171 <                try {
1172 <                    if (tabAt(tab, i) == f) {
1173 <                        validated = true;
1174 <                        for (Node e = f, pred = null;;) {
1175 <                            Object ek, ev;
1176 <                            if ((e.hash & HASH_BITS) == h &&
1177 <                                ((ev = e.val) != null) &&
1178 <                                ((ek = e.key) == k || k.equals(ek))) {
1179 <                                if (cv == null || cv == ev || cv.equals(ev)) {
1180 <                                    oldVal = ev;
1181 <                                    if ((e.val = v) == null) {
1182 <                                        deleted = true;
1183 <                                        Node en = e.next;
1184 <                                        if (pred != null)
1185 <                                            pred.next = en;
1186 <                                        else
1187 <                                            setTabAt(tab, i, en);
1188 <                                    }
1189 <                                }
1190 <                                break;
1191 <                            }
1192 <                            pred = e;
1193 <                            if ((e = e.next) == null)
1194 <                                break;
1195 <                        }
1196 <                    }
1197 <                } finally {
1198 <                    if (!f.casHash(fh | LOCKED, fh)) {
1199 <                        f.hash = fh;
1200 <                        synchronized (f) { f.notifyAll(); };
1201 <                    }
1202 <                }
1203 <                if (validated) {
1204 <                    if (deleted)
1205 <                        counter.add(-1L);
1206 <                    break;
1207 <                }
1208 <            }
1209 <        }
1210 <        return oldVal;
1211 <    }
1212 <
1213 <    /*
1214 <     * Internal versions of the six insertion methods, each a
1215 <     * little more complicated than the last. All have
1216 <     * the same basic structure as the first (internalPut):
1217 <     *  1. If table uninitialized, create
1218 <     *  2. If bin empty, try to CAS new node
1219 <     *  3. If bin stale, use new table
1220 <     *  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1221 <     *  5. Lock and validate; if valid, scan and add or update
1222 <     *
1223 <     * The others interweave other checks and/or alternative actions:
1224 <     *  * Plain put checks for and performs resize after insertion.
1225 <     *  * putIfAbsent prescans for mapping without lock (and fails to add
1226 <     *    if present), which also makes pre-emptive resize checks worthwhile.
1227 <     *  * computeIfAbsent extends form used in putIfAbsent with additional
1228 <     *    mechanics to deal with, calls, potential exceptions and null
1229 <     *    returns from function call.
1230 <     *  * compute uses the same function-call mechanics, but without
1231 <     *    the prescans
1232 <     *  * merge acts as putIfAbsent in the absent case, but invokes the
1233 <     *    update function if present
1234 <     *  * putAll attempts to pre-allocate enough table space
1235 <     *    and more lazily performs count updates and checks.
1236 <     *
1237 <     * Someday when details settle down a bit more, it might be worth
1238 <     * some factoring to reduce sprawl.
1239 <     */
1240 <
1241 <    /** Implementation for put */
1242 <    private final Object internalPut(Object k, Object v) {
1243 <        int h = spread(k.hashCode());
1244 <        int count = 0;
1245 <        for (Node[] tab = table;;) {
1246 <            int i; Node f; int fh; Object fk;
1247 <            if (tab == null)
1248 <                tab = initTable();
1249 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1250 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1251 <                    break;                   // no lock when adding to empty bin
1252 <            }
1253 <            else if ((fh = f.hash) == MOVED) {
1254 <                if ((fk = f.key) instanceof TreeBin) {
1255 <                    TreeBin t = (TreeBin)fk;
1256 <                    Object oldVal = null;
1257 <                    t.acquire(0);
1258 <                    try {
1259 <                        if (tabAt(tab, i) == f) {
1260 <                            count = 2;
1261 <                            TreeNode p = t.putTreeNode(h, k, v);
1262 <                            if (p != null) {
1263 <                                oldVal = p.val;
1264 <                                p.val = v;
1265 <                            }
1266 <                        }
1267 <                    } finally {
1268 <                        t.release(0);
1269 <                    }
1270 <                    if (count != 0) {
1271 <                        if (oldVal != null)
1272 <                            return oldVal;
1273 <                        break;
1274 <                    }
1275 <                }
1276 <                else
1277 <                    tab = (Node[])fk;
1278 <            }
1279 <            else if ((fh & LOCKED) != 0) {
1280 <                checkForResize();
1281 <                f.tryAwaitLock(tab, i);
1282 <            }
1283 <            else if (f.casHash(fh, fh | LOCKED)) {
1284 <                Object oldVal = null;
1285 <                try {                        // needed in case equals() throws
1286 <                    if (tabAt(tab, i) == f) {
1287 <                        count = 1;
1288 <                        for (Node e = f;; ++count) {
1289 <                            Object ek, ev;
1290 <                            if ((e.hash & HASH_BITS) == h &&
1291 <                                (ev = e.val) != null &&
1292 <                                ((ek = e.key) == k || k.equals(ek))) {
1293 <                                oldVal = ev;
1294 <                                e.val = v;
1295 <                                break;
1296 <                            }
1297 <                            Node last = e;
1298 <                            if ((e = e.next) == null) {
1299 <                                last.next = new Node(h, k, v, null);
1300 <                                if (count >= TREE_THRESHOLD)
1301 <                                    replaceWithTreeBin(tab, i, k);
1302 <                                break;
1303 <                            }
1304 <                        }
1305 <                    }
1306 <                } finally {                  // unlock and signal if needed
1307 <                    if (!f.casHash(fh | LOCKED, fh)) {
1308 <                        f.hash = fh;
1309 <                        synchronized (f) { f.notifyAll(); };
1310 <                    }
1311 <                }
1312 <                if (count != 0) {
1313 <                    if (oldVal != null)
1314 <                        return oldVal;
1315 <                    if (tab.length <= 64)
1316 <                        count = 2;
1317 <                    break;
1318 <                }
1319 <            }
1320 <        }
1321 <        counter.add(1L);
1322 <        if (count > 1)
1323 <            checkForResize();
1324 <        return null;
1325 <    }
1326 <
1327 <    /** Implementation for putIfAbsent */
1328 <    private final Object internalPutIfAbsent(Object k, Object v) {
1329 <        int h = spread(k.hashCode());
1330 <        int count = 0;
1331 <        for (Node[] tab = table;;) {
1332 <            int i; Node f; int fh; Object fk, fv;
1333 <            if (tab == null)
1334 <                tab = initTable();
1335 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1336 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1337 <                    break;
1338 <            }
1339 <            else if ((fh = f.hash) == MOVED) {
1340 <                if ((fk = f.key) instanceof TreeBin) {
1341 <                    TreeBin t = (TreeBin)fk;
1342 <                    Object oldVal = null;
1343 <                    t.acquire(0);
1344 <                    try {
1345 <                        if (tabAt(tab, i) == f) {
1346 <                            count = 2;
1347 <                            TreeNode p = t.putTreeNode(h, k, v);
1348 <                            if (p != null)
1349 <                                oldVal = p.val;
1350 <                        }
1351 <                    } finally {
1352 <                        t.release(0);
1353 <                    }
1354 <                    if (count != 0) {
1355 <                        if (oldVal != null)
1356 <                            return oldVal;
1357 <                        break;
1358 <                    }
1359 <                }
1360 <                else
1361 <                    tab = (Node[])fk;
1362 <            }
1363 <            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1364 <                     ((fk = f.key) == k || k.equals(fk)))
1365 <                return fv;
1366 <            else {
1367 <                Node g = f.next;
1368 <                if (g != null) { // at least 2 nodes -- search and maybe resize
1369 <                    for (Node e = g;;) {
1370 <                        Object ek, ev;
1371 <                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1372 <                            ((ek = e.key) == k || k.equals(ek)))
1373 <                            return ev;
1374 <                        if ((e = e.next) == null) {
1375 <                            checkForResize();
1376 <                            break;
1377 <                        }
1378 <                    }
1379 <                }
1380 <                if (((fh = f.hash) & LOCKED) != 0) {
1381 <                    checkForResize();
1382 <                    f.tryAwaitLock(tab, i);
1383 <                }
1384 <                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1385 <                    Object oldVal = null;
1386 <                    try {
1387 <                        if (tabAt(tab, i) == f) {
1388 <                            count = 1;
1389 <                            for (Node e = f;; ++count) {
1390 <                                Object ek, ev;
1391 <                                if ((e.hash & HASH_BITS) == h &&
1392 <                                    (ev = e.val) != null &&
1393 <                                    ((ek = e.key) == k || k.equals(ek))) {
1394 <                                    oldVal = ev;
1395 <                                    break;
1396 <                                }
1397 <                                Node last = e;
1398 <                                if ((e = e.next) == null) {
1399 <                                    last.next = new Node(h, k, v, null);
1400 <                                    if (count >= TREE_THRESHOLD)
1401 <                                        replaceWithTreeBin(tab, i, k);
1402 <                                    break;
1403 <                                }
1404 <                            }
1405 <                        }
1406 <                    } finally {
1407 <                        if (!f.casHash(fh | LOCKED, fh)) {
1408 <                            f.hash = fh;
1409 <                            synchronized (f) { f.notifyAll(); };
1410 <                        }
1411 <                    }
1412 <                    if (count != 0) {
1413 <                        if (oldVal != null)
1414 <                            return oldVal;
1415 <                        if (tab.length <= 64)
1416 <                            count = 2;
1417 <                        break;
1418 <                    }
1419 <                }
1420 <            }
1421 <        }
1422 <        counter.add(1L);
1423 <        if (count > 1)
1424 <            checkForResize();
1425 <        return null;
668 >    static final int spread(int h) {
669 >        return (h ^ (h >>> 16)) & HASH_BITS;
670      }
671  
1428    /** Implementation for computeIfAbsent */
1429    private final Object internalComputeIfAbsent(K k,
1430                                                 Fun<? super K, ?> mf) {
1431        int h = spread(k.hashCode());
1432        Object val = null;
1433        int count = 0;
1434        for (Node[] tab = table;;) {
1435            Node f; int i, fh; Object fk, fv;
1436            if (tab == null)
1437                tab = initTable();
1438            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1439                Node node = new Node(fh = h | LOCKED, k, null, null);
1440                if (casTabAt(tab, i, null, node)) {
1441                    count = 1;
1442                    try {
1443                        if ((val = mf.apply(k)) != null)
1444                            node.val = val;
1445                    } finally {
1446                        if (val == null)
1447                            setTabAt(tab, i, null);
1448                        if (!node.casHash(fh, h)) {
1449                            node.hash = h;
1450                            synchronized (node) { node.notifyAll(); };
1451                        }
1452                    }
1453                }
1454                if (count != 0)
1455                    break;
1456            }
1457            else if ((fh = f.hash) == MOVED) {
1458                if ((fk = f.key) instanceof TreeBin) {
1459                    TreeBin t = (TreeBin)fk;
1460                    boolean added = false;
1461                    t.acquire(0);
1462                    try {
1463                        if (tabAt(tab, i) == f) {
1464                            count = 1;
1465                            TreeNode p = t.getTreeNode(h, k, t.root);
1466                            if (p != null)
1467                                val = p.val;
1468                            else if ((val = mf.apply(k)) != null) {
1469                                added = true;
1470                                count = 2;
1471                                t.putTreeNode(h, k, val);
1472                            }
1473                        }
1474                    } finally {
1475                        t.release(0);
1476                    }
1477                    if (count != 0) {
1478                        if (!added)
1479                            return val;
1480                        break;
1481                    }
1482                }
1483                else
1484                    tab = (Node[])fk;
1485            }
1486            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1487                     ((fk = f.key) == k || k.equals(fk)))
1488                return fv;
1489            else {
1490                Node g = f.next;
1491                if (g != null) {
1492                    for (Node e = g;;) {
1493                        Object ek, ev;
1494                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1495                            ((ek = e.key) == k || k.equals(ek)))
1496                            return ev;
1497                        if ((e = e.next) == null) {
1498                            checkForResize();
1499                            break;
1500                        }
1501                    }
1502                }
1503                if (((fh = f.hash) & LOCKED) != 0) {
1504                    checkForResize();
1505                    f.tryAwaitLock(tab, i);
1506                }
1507                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1508                    boolean added = false;
1509                    try {
1510                        if (tabAt(tab, i) == f) {
1511                            count = 1;
1512                            for (Node e = f;; ++count) {
1513                                Object ek, ev;
1514                                if ((e.hash & HASH_BITS) == h &&
1515                                    (ev = e.val) != null &&
1516                                    ((ek = e.key) == k || k.equals(ek))) {
1517                                    val = ev;
1518                                    break;
1519                                }
1520                                Node last = e;
1521                                if ((e = e.next) == null) {
1522                                    if ((val = mf.apply(k)) != null) {
1523                                        added = true;
1524                                        last.next = new Node(h, k, val, null);
1525                                        if (count >= TREE_THRESHOLD)
1526                                            replaceWithTreeBin(tab, i, k);
1527                                    }
1528                                    break;
1529                                }
1530                            }
1531                        }
1532                    } finally {
1533                        if (!f.casHash(fh | LOCKED, fh)) {
1534                            f.hash = fh;
1535                            synchronized (f) { f.notifyAll(); };
1536                        }
1537                    }
1538                    if (count != 0) {
1539                        if (!added)
1540                            return val;
1541                        if (tab.length <= 64)
1542                            count = 2;
1543                        break;
1544                    }
1545                }
1546            }
1547        }
1548        if (val != null) {
1549            counter.add(1L);
1550            if (count > 1)
1551                checkForResize();
1552        }
1553        return val;
1554    }
1555
1556    /** Implementation for compute */
1557    @SuppressWarnings("unchecked") private final Object internalCompute
1558        (K k, boolean onlyIfPresent, BiFun<? super K, ? super V, ? extends V> mf) {
1559        int h = spread(k.hashCode());
1560        Object val = null;
1561        int delta = 0;
1562        int count = 0;
1563        for (Node[] tab = table;;) {
1564            Node f; int i, fh; Object fk;
1565            if (tab == null)
1566                tab = initTable();
1567            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1568                if (onlyIfPresent)
1569                    break;
1570                Node node = new Node(fh = h | LOCKED, k, null, null);
1571                if (casTabAt(tab, i, null, node)) {
1572                    try {
1573                        count = 1;
1574                        if ((val = mf.apply(k, null)) != null) {
1575                            node.val = val;
1576                            delta = 1;
1577                        }
1578                    } finally {
1579                        if (delta == 0)
1580                            setTabAt(tab, i, null);
1581                        if (!node.casHash(fh, h)) {
1582                            node.hash = h;
1583                            synchronized (node) { node.notifyAll(); };
1584                        }
1585                    }
1586                }
1587                if (count != 0)
1588                    break;
1589            }
1590            else if ((fh = f.hash) == MOVED) {
1591                if ((fk = f.key) instanceof TreeBin) {
1592                    TreeBin t = (TreeBin)fk;
1593                    t.acquire(0);
1594                    try {
1595                        if (tabAt(tab, i) == f) {
1596                            count = 1;
1597                            TreeNode p = t.getTreeNode(h, k, t.root);
1598                            Object pv = (p == null) ? null : p.val;
1599                            if ((val = mf.apply(k, (V)pv)) != null) {
1600                                if (p != null)
1601                                    p.val = val;
1602                                else {
1603                                    count = 2;
1604                                    delta = 1;
1605                                    t.putTreeNode(h, k, val);
1606                                }
1607                            }
1608                            else if (p != null) {
1609                                delta = -1;
1610                                t.deleteTreeNode(p);
1611                            }
1612                        }
1613                    } finally {
1614                        t.release(0);
1615                    }
1616                    if (count != 0)
1617                        break;
1618                }
1619                else
1620                    tab = (Node[])fk;
1621            }
1622            else if ((fh & LOCKED) != 0) {
1623                checkForResize();
1624                f.tryAwaitLock(tab, i);
1625            }
1626            else if (f.casHash(fh, fh | LOCKED)) {
1627                try {
1628                    if (tabAt(tab, i) == f) {
1629                        count = 1;
1630                        for (Node e = f, pred = null;; ++count) {
1631                            Object ek, ev;
1632                            if ((e.hash & HASH_BITS) == h &&
1633                                (ev = e.val) != null &&
1634                                ((ek = e.key) == k || k.equals(ek))) {
1635                                val = mf.apply(k, (V)ev);
1636                                if (val != null)
1637                                    e.val = val;
1638                                else {
1639                                    delta = -1;
1640                                    Node en = e.next;
1641                                    if (pred != null)
1642                                        pred.next = en;
1643                                    else
1644                                        setTabAt(tab, i, en);
1645                                }
1646                                break;
1647                            }
1648                            pred = e;
1649                            if ((e = e.next) == null) {
1650                                if (!onlyIfPresent && (val = mf.apply(k, null)) != null) {
1651                                    pred.next = new Node(h, k, val, null);
1652                                    delta = 1;
1653                                    if (count >= TREE_THRESHOLD)
1654                                        replaceWithTreeBin(tab, i, k);
1655                                }
1656                                break;
1657                            }
1658                        }
1659                    }
1660                } finally {
1661                    if (!f.casHash(fh | LOCKED, fh)) {
1662                        f.hash = fh;
1663                        synchronized (f) { f.notifyAll(); };
1664                    }
1665                }
1666                if (count != 0) {
1667                    if (tab.length <= 64)
1668                        count = 2;
1669                    break;
1670                }
1671            }
1672        }
1673        if (delta != 0) {
1674            counter.add((long)delta);
1675            if (count > 1)
1676                checkForResize();
1677        }
1678        return val;
1679    }
1680
1681    /** Implementation for merge */
1682    @SuppressWarnings("unchecked") private final Object internalMerge
1683        (K k, V v, BiFun<? super V, ? super V, ? extends V> mf) {
1684        int h = spread(k.hashCode());
1685        Object val = null;
1686        int delta = 0;
1687        int count = 0;
1688        for (Node[] tab = table;;) {
1689            int i; Node f; int fh; Object fk, fv;
1690            if (tab == null)
1691                tab = initTable();
1692            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1693                if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1694                    delta = 1;
1695                    val = v;
1696                    break;
1697                }
1698            }
1699            else if ((fh = f.hash) == MOVED) {
1700                if ((fk = f.key) instanceof TreeBin) {
1701                    TreeBin t = (TreeBin)fk;
1702                    t.acquire(0);
1703                    try {
1704                        if (tabAt(tab, i) == f) {
1705                            count = 1;
1706                            TreeNode p = t.getTreeNode(h, k, t.root);
1707                            val = (p == null) ? v : mf.apply((V)p.val, v);
1708                            if (val != null) {
1709                                if (p != null)
1710                                    p.val = val;
1711                                else {
1712                                    count = 2;
1713                                    delta = 1;
1714                                    t.putTreeNode(h, k, val);
1715                                }
1716                            }
1717                            else if (p != null) {
1718                                delta = -1;
1719                                t.deleteTreeNode(p);
1720                            }
1721                        }
1722                    } finally {
1723                        t.release(0);
1724                    }
1725                    if (count != 0)
1726                        break;
1727                }
1728                else
1729                    tab = (Node[])fk;
1730            }
1731            else if ((fh & LOCKED) != 0) {
1732                checkForResize();
1733                f.tryAwaitLock(tab, i);
1734            }
1735            else if (f.casHash(fh, fh | LOCKED)) {
1736                try {
1737                    if (tabAt(tab, i) == f) {
1738                        count = 1;
1739                        for (Node e = f, pred = null;; ++count) {
1740                            Object ek, ev;
1741                            if ((e.hash & HASH_BITS) == h &&
1742                                (ev = e.val) != null &&
1743                                ((ek = e.key) == k || k.equals(ek))) {
1744                                val = mf.apply(v, (V)ev);
1745                                if (val != null)
1746                                    e.val = val;
1747                                else {
1748                                    delta = -1;
1749                                    Node en = e.next;
1750                                    if (pred != null)
1751                                        pred.next = en;
1752                                    else
1753                                        setTabAt(tab, i, en);
1754                                }
1755                                break;
1756                            }
1757                            pred = e;
1758                            if ((e = e.next) == null) {
1759                                val = v;
1760                                pred.next = new Node(h, k, val, null);
1761                                delta = 1;
1762                                if (count >= TREE_THRESHOLD)
1763                                    replaceWithTreeBin(tab, i, k);
1764                                break;
1765                            }
1766                        }
1767                    }
1768                } finally {
1769                    if (!f.casHash(fh | LOCKED, fh)) {
1770                        f.hash = fh;
1771                        synchronized (f) { f.notifyAll(); };
1772                    }
1773                }
1774                if (count != 0) {
1775                    if (tab.length <= 64)
1776                        count = 2;
1777                    break;
1778                }
1779            }
1780        }
1781        if (delta != 0) {
1782            counter.add((long)delta);
1783            if (count > 1)
1784                checkForResize();
1785        }
1786        return val;
1787    }
1788
1789    /** Implementation for putAll */
1790    private final void internalPutAll(Map<?, ?> m) {
1791        tryPresize(m.size());
1792        long delta = 0L;     // number of uncommitted additions
1793        boolean npe = false; // to throw exception on exit for nulls
1794        try {                // to clean up counts on other exceptions
1795            for (Map.Entry<?, ?> entry : m.entrySet()) {
1796                Object k, v;
1797                if (entry == null || (k = entry.getKey()) == null ||
1798                    (v = entry.getValue()) == null) {
1799                    npe = true;
1800                    break;
1801                }
1802                int h = spread(k.hashCode());
1803                for (Node[] tab = table;;) {
1804                    int i; Node f; int fh; Object fk;
1805                    if (tab == null)
1806                        tab = initTable();
1807                    else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1808                        if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1809                            ++delta;
1810                            break;
1811                        }
1812                    }
1813                    else if ((fh = f.hash) == MOVED) {
1814                        if ((fk = f.key) instanceof TreeBin) {
1815                            TreeBin t = (TreeBin)fk;
1816                            boolean validated = false;
1817                            t.acquire(0);
1818                            try {
1819                                if (tabAt(tab, i) == f) {
1820                                    validated = true;
1821                                    TreeNode p = t.getTreeNode(h, k, t.root);
1822                                    if (p != null)
1823                                        p.val = v;
1824                                    else {
1825                                        t.putTreeNode(h, k, v);
1826                                        ++delta;
1827                                    }
1828                                }
1829                            } finally {
1830                                t.release(0);
1831                            }
1832                            if (validated)
1833                                break;
1834                        }
1835                        else
1836                            tab = (Node[])fk;
1837                    }
1838                    else if ((fh & LOCKED) != 0) {
1839                        counter.add(delta);
1840                        delta = 0L;
1841                        checkForResize();
1842                        f.tryAwaitLock(tab, i);
1843                    }
1844                    else if (f.casHash(fh, fh | LOCKED)) {
1845                        int count = 0;
1846                        try {
1847                            if (tabAt(tab, i) == f) {
1848                                count = 1;
1849                                for (Node e = f;; ++count) {
1850                                    Object ek, ev;
1851                                    if ((e.hash & HASH_BITS) == h &&
1852                                        (ev = e.val) != null &&
1853                                        ((ek = e.key) == k || k.equals(ek))) {
1854                                        e.val = v;
1855                                        break;
1856                                    }
1857                                    Node last = e;
1858                                    if ((e = e.next) == null) {
1859                                        ++delta;
1860                                        last.next = new Node(h, k, v, null);
1861                                        if (count >= TREE_THRESHOLD)
1862                                            replaceWithTreeBin(tab, i, k);
1863                                        break;
1864                                    }
1865                                }
1866                            }
1867                        } finally {
1868                            if (!f.casHash(fh | LOCKED, fh)) {
1869                                f.hash = fh;
1870                                synchronized (f) { f.notifyAll(); };
1871                            }
1872                        }
1873                        if (count != 0) {
1874                            if (count > 1) {
1875                                counter.add(delta);
1876                                delta = 0L;
1877                                checkForResize();
1878                            }
1879                            break;
1880                        }
1881                    }
1882                }
1883            }
1884        } finally {
1885            if (delta != 0)
1886                counter.add(delta);
1887        }
1888        if (npe)
1889            throw new NullPointerException();
1890    }
1891
1892    /* ---------------- Table Initialization and Resizing -------------- */
1893
672      /**
673       * Returns a power of two table size for the given desired capacity.
674       * See Hackers Delight, sec 3.2
# Line 1906 | Line 684 | public class ConcurrentHashMapV8<K, V>
684      }
685  
686      /**
687 <     * Initializes table, using the size recorded in sizeCtl.
687 >     * Returns x's Class if it is of the form "class C implements
688 >     * Comparable<C>", else null.
689       */
690 <    private final Node[] initTable() {
691 <        Node[] tab; int sc;
692 <        while ((tab = table) == null) {
693 <            if ((sc = sizeCtl) < 0)
694 <                Thread.yield(); // lost initialization race; just spin
695 <            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
696 <                try {
697 <                    if ((tab = table) == null) {
698 <                        int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
699 <                        tab = table = new Node[n];
700 <                        sc = n - (n >>> 2);
701 <                    }
702 <                } finally {
1924 <                    sizeCtl = sc;
1925 <                }
1926 <                break;
1927 <            }
1928 <        }
1929 <        return tab;
1930 <    }
1931 <
1932 <    /**
1933 <     * If table is too small and not already resizing, creates next
1934 <     * table and transfers bins.  Rechecks occupancy after a transfer
1935 <     * to see if another resize is already needed because resizings
1936 <     * are lagging additions.
1937 <     */
1938 <    private final void checkForResize() {
1939 <        Node[] tab; int n, sc;
1940 <        while ((tab = table) != null &&
1941 <               (n = tab.length) < MAXIMUM_CAPACITY &&
1942 <               (sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1943 <               UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1944 <            try {
1945 <                if (tab == table) {
1946 <                    table = rebuild(tab);
1947 <                    sc = (n << 1) - (n >>> 1);
690 >    static Class<?> comparableClassFor(Object x) {
691 >        if (x instanceof Comparable) {
692 >            Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
693 >            if ((c = x.getClass()) == String.class) // bypass checks
694 >                return c;
695 >            if ((ts = c.getGenericInterfaces()) != null) {
696 >                for (int i = 0; i < ts.length; ++i) {
697 >                    if (((t = ts[i]) instanceof ParameterizedType) &&
698 >                        ((p = (ParameterizedType)t).getRawType() ==
699 >                         Comparable.class) &&
700 >                        (as = p.getActualTypeArguments()) != null &&
701 >                        as.length == 1 && as[0] == c) // type arg is c
702 >                        return c;
703                  }
1949            } finally {
1950                sizeCtl = sc;
704              }
705          }
706 +        return null;
707      }
708  
709      /**
710 <     * Tries to presize table to accommodate the given number of elements.
711 <     *
1958 <     * @param size number of elements (doesn't need to be perfectly accurate)
710 >     * Returns k.compareTo(x) if x matches kc (k's screened comparable
711 >     * class), else 0.
712       */
713 <    private final void tryPresize(int size) {
714 <        int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
715 <            tableSizeFor(size + (size >>> 1) + 1);
716 <        int sc;
1964 <        while ((sc = sizeCtl) >= 0) {
1965 <            Node[] tab = table; int n;
1966 <            if (tab == null || (n = tab.length) == 0) {
1967 <                n = (sc > c) ? sc : c;
1968 <                if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1969 <                    try {
1970 <                        if (table == tab) {
1971 <                            table = new Node[n];
1972 <                            sc = n - (n >>> 2);
1973 <                        }
1974 <                    } finally {
1975 <                        sizeCtl = sc;
1976 <                    }
1977 <                }
1978 <            }
1979 <            else if (c <= sc || n >= MAXIMUM_CAPACITY)
1980 <                break;
1981 <            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1982 <                try {
1983 <                    if (table == tab) {
1984 <                        table = rebuild(tab);
1985 <                        sc = (n << 1) - (n >>> 1);
1986 <                    }
1987 <                } finally {
1988 <                    sizeCtl = sc;
1989 <                }
1990 <            }
1991 <        }
713 >    @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
714 >    static int compareComparables(Class<?> kc, Object k, Object x) {
715 >        return (x == null || x.getClass() != kc ? 0 :
716 >                ((Comparable)k).compareTo(x));
717      }
718  
719 +    /* ---------------- Table element access -------------- */
720 +
721      /*
722 <     * Moves and/or copies the nodes in each bin to new table. See
723 <     * above for explanation.
724 <     *
725 <     * @return the new table
726 <     */
727 <    private static final Node[] rebuild(Node[] tab) {
728 <        int n = tab.length;
729 <        Node[] nextTab = new Node[n << 1];
730 <        Node fwd = new Node(MOVED, nextTab, null, null);
731 <        int[] buffer = null;       // holds bins to revisit; null until needed
732 <        Node rev = null;           // reverse forwarder; null until needed
733 <        int nbuffered = 0;         // the number of bins in buffer list
734 <        int bufferIndex = 0;       // buffer index of current buffered bin
735 <        int bin = n - 1;           // current non-buffered bin or -1 if none
736 <
737 <        for (int i = bin;;) {      // start upwards sweep
738 <            int fh; Node f;
739 <            if ((f = tabAt(tab, i)) == null) {
740 <                if (bin >= 0) {    // Unbuffered; no lock needed (or available)
741 <                    if (!casTabAt(tab, i, f, fwd))
742 <                        continue;
743 <                }
744 <                else {             // transiently use a locked forwarding node
2018 <                    Node g = new Node(MOVED|LOCKED, nextTab, null, null);
2019 <                    if (!casTabAt(tab, i, f, g))
2020 <                        continue;
2021 <                    setTabAt(nextTab, i, null);
2022 <                    setTabAt(nextTab, i + n, null);
2023 <                    setTabAt(tab, i, fwd);
2024 <                    if (!g.casHash(MOVED|LOCKED, MOVED)) {
2025 <                        g.hash = MOVED;
2026 <                        synchronized (g) { g.notifyAll(); }
2027 <                    }
2028 <                }
2029 <            }
2030 <            else if ((fh = f.hash) == MOVED) {
2031 <                Object fk = f.key;
2032 <                if (fk instanceof TreeBin) {
2033 <                    TreeBin t = (TreeBin)fk;
2034 <                    boolean validated = false;
2035 <                    t.acquire(0);
2036 <                    try {
2037 <                        if (tabAt(tab, i) == f) {
2038 <                            validated = true;
2039 <                            splitTreeBin(nextTab, i, t);
2040 <                            setTabAt(tab, i, fwd);
2041 <                        }
2042 <                    } finally {
2043 <                        t.release(0);
2044 <                    }
2045 <                    if (!validated)
2046 <                        continue;
2047 <                }
2048 <            }
2049 <            else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
2050 <                boolean validated = false;
2051 <                try {              // split to lo and hi lists; copying as needed
2052 <                    if (tabAt(tab, i) == f) {
2053 <                        validated = true;
2054 <                        splitBin(nextTab, i, f);
2055 <                        setTabAt(tab, i, fwd);
2056 <                    }
2057 <                } finally {
2058 <                    if (!f.casHash(fh | LOCKED, fh)) {
2059 <                        f.hash = fh;
2060 <                        synchronized (f) { f.notifyAll(); };
2061 <                    }
2062 <                }
2063 <                if (!validated)
2064 <                    continue;
2065 <            }
2066 <            else {
2067 <                if (buffer == null) // initialize buffer for revisits
2068 <                    buffer = new int[TRANSFER_BUFFER_SIZE];
2069 <                if (bin < 0 && bufferIndex > 0) {
2070 <                    int j = buffer[--bufferIndex];
2071 <                    buffer[bufferIndex] = i;
2072 <                    i = j;         // swap with another bin
2073 <                    continue;
2074 <                }
2075 <                if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
2076 <                    f.tryAwaitLock(tab, i);
2077 <                    continue;      // no other options -- block
2078 <                }
2079 <                if (rev == null)   // initialize reverse-forwarder
2080 <                    rev = new Node(MOVED, tab, null, null);
2081 <                if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
2082 <                    continue;      // recheck before adding to list
2083 <                buffer[nbuffered++] = i;
2084 <                setTabAt(nextTab, i, rev);     // install place-holders
2085 <                setTabAt(nextTab, i + n, rev);
2086 <            }
2087 <
2088 <            if (bin > 0)
2089 <                i = --bin;
2090 <            else if (buffer != null && nbuffered > 0) {
2091 <                bin = -1;
2092 <                i = buffer[bufferIndex = --nbuffered];
2093 <            }
2094 <            else
2095 <                return nextTab;
2096 <        }
722 >     * Volatile access methods are used for table elements as well as
723 >     * elements of in-progress next table while resizing.  All uses of
724 >     * the tab arguments must be null checked by callers.  All callers
725 >     * also paranoically precheck that tab's length is not zero (or an
726 >     * equivalent check), thus ensuring that any index argument taking
727 >     * the form of a hash value anded with (length - 1) is a valid
728 >     * index.  Note that, to be correct wrt arbitrary concurrency
729 >     * errors by users, these checks must operate on local variables,
730 >     * which accounts for some odd-looking inline assignments below.
731 >     * Note that calls to setTabAt always occur within locked regions,
732 >     * and so in principle require only release ordering, not need
733 >     * full volatile semantics, but are currently coded as volatile
734 >     * writes to be conservative.
735 >     */
736 >
737 >    @SuppressWarnings("unchecked")
738 >    static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
739 >        return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
740 >    }
741 >
742 >    static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
743 >                                        Node<K,V> c, Node<K,V> v) {
744 >        return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
745      }
746  
747 +    static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
748 +        U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
749 +    }
750 +
751 +    /* ---------------- Fields -------------- */
752 +
753      /**
754 <     * Splits a normal bin with list headed by e into lo and hi parts;
755 <     * installs in given table.
754 >     * The array of bins. Lazily initialized upon first insertion.
755 >     * Size is always a power of two. Accessed directly by iterators.
756       */
757 <    private static void splitBin(Node[] nextTab, int i, Node e) {
2104 <        int bit = nextTab.length >>> 1; // bit to split on
2105 <        int runBit = e.hash & bit;
2106 <        Node lastRun = e, lo = null, hi = null;
2107 <        for (Node p = e.next; p != null; p = p.next) {
2108 <            int b = p.hash & bit;
2109 <            if (b != runBit) {
2110 <                runBit = b;
2111 <                lastRun = p;
2112 <            }
2113 <        }
2114 <        if (runBit == 0)
2115 <            lo = lastRun;
2116 <        else
2117 <            hi = lastRun;
2118 <        for (Node p = e; p != lastRun; p = p.next) {
2119 <            int ph = p.hash & HASH_BITS;
2120 <            Object pk = p.key, pv = p.val;
2121 <            if ((ph & bit) == 0)
2122 <                lo = new Node(ph, pk, pv, lo);
2123 <            else
2124 <                hi = new Node(ph, pk, pv, hi);
2125 <        }
2126 <        setTabAt(nextTab, i, lo);
2127 <        setTabAt(nextTab, i + bit, hi);
2128 <    }
757 >    transient volatile Node<K,V>[] table;
758  
759      /**
760 <     * Splits a tree bin into lo and hi parts; installs in given table.
760 >     * The next table to use; non-null only while resizing.
761       */
762 <    private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
2134 <        int bit = nextTab.length >>> 1;
2135 <        TreeBin lt = new TreeBin();
2136 <        TreeBin ht = new TreeBin();
2137 <        int lc = 0, hc = 0;
2138 <        for (Node e = t.first; e != null; e = e.next) {
2139 <            int h = e.hash & HASH_BITS;
2140 <            Object k = e.key, v = e.val;
2141 <            if ((h & bit) == 0) {
2142 <                ++lc;
2143 <                lt.putTreeNode(h, k, v);
2144 <            }
2145 <            else {
2146 <                ++hc;
2147 <                ht.putTreeNode(h, k, v);
2148 <            }
2149 <        }
2150 <        Node ln, hn; // throw away trees if too small
2151 <        if (lc <= (TREE_THRESHOLD >>> 1)) {
2152 <            ln = null;
2153 <            for (Node p = lt.first; p != null; p = p.next)
2154 <                ln = new Node(p.hash, p.key, p.val, ln);
2155 <        }
2156 <        else
2157 <            ln = new Node(MOVED, lt, null, null);
2158 <        setTabAt(nextTab, i, ln);
2159 <        if (hc <= (TREE_THRESHOLD >>> 1)) {
2160 <            hn = null;
2161 <            for (Node p = ht.first; p != null; p = p.next)
2162 <                hn = new Node(p.hash, p.key, p.val, hn);
2163 <        }
2164 <        else
2165 <            hn = new Node(MOVED, ht, null, null);
2166 <        setTabAt(nextTab, i + bit, hn);
2167 <    }
762 >    private transient volatile Node<K,V>[] nextTable;
763  
764      /**
765 <     * Implementation for clear. Steps through each bin, removing all
766 <     * nodes.
765 >     * Base counter value, used mainly when there is no contention,
766 >     * but also as a fallback during table initialization
767 >     * races. Updated via CAS.
768       */
769 <    private final void internalClear() {
2174 <        long delta = 0L; // negative number of deletions
2175 <        int i = 0;
2176 <        Node[] tab = table;
2177 <        while (tab != null && i < tab.length) {
2178 <            int fh; Object fk;
2179 <            Node f = tabAt(tab, i);
2180 <            if (f == null)
2181 <                ++i;
2182 <            else if ((fh = f.hash) == MOVED) {
2183 <                if ((fk = f.key) instanceof TreeBin) {
2184 <                    TreeBin t = (TreeBin)fk;
2185 <                    t.acquire(0);
2186 <                    try {
2187 <                        if (tabAt(tab, i) == f) {
2188 <                            for (Node p = t.first; p != null; p = p.next) {
2189 <                                if (p.val != null) { // (currently always true)
2190 <                                    p.val = null;
2191 <                                    --delta;
2192 <                                }
2193 <                            }
2194 <                            t.first = null;
2195 <                            t.root = null;
2196 <                            ++i;
2197 <                        }
2198 <                    } finally {
2199 <                        t.release(0);
2200 <                    }
2201 <                }
2202 <                else
2203 <                    tab = (Node[])fk;
2204 <            }
2205 <            else if ((fh & LOCKED) != 0) {
2206 <                counter.add(delta); // opportunistically update count
2207 <                delta = 0L;
2208 <                f.tryAwaitLock(tab, i);
2209 <            }
2210 <            else if (f.casHash(fh, fh | LOCKED)) {
2211 <                try {
2212 <                    if (tabAt(tab, i) == f) {
2213 <                        for (Node e = f; e != null; e = e.next) {
2214 <                            if (e.val != null) {  // (currently always true)
2215 <                                e.val = null;
2216 <                                --delta;
2217 <                            }
2218 <                        }
2219 <                        setTabAt(tab, i, null);
2220 <                        ++i;
2221 <                    }
2222 <                } finally {
2223 <                    if (!f.casHash(fh | LOCKED, fh)) {
2224 <                        f.hash = fh;
2225 <                        synchronized (f) { f.notifyAll(); };
2226 <                    }
2227 <                }
2228 <            }
2229 <        }
2230 <        if (delta != 0)
2231 <            counter.add(delta);
2232 <    }
769 >    private transient volatile long baseCount;
770  
771 <    /* ----------------Table Traversal -------------- */
771 >    /**
772 >     * Table initialization and resizing control.  When negative, the
773 >     * table is being initialized or resized: -1 for initialization,
774 >     * else -(1 + the number of active resizing threads).  Otherwise,
775 >     * when table is null, holds the initial table size to use upon
776 >     * creation, or 0 for default. After initialization, holds the
777 >     * next element count value upon which to resize the table.
778 >     */
779 >    private transient volatile int sizeCtl;
780  
781      /**
782 <     * Encapsulates traversal for methods such as containsValue; also
783 <     * serves as a base class for other iterators and bulk tasks.
784 <     *
2240 <     * At each step, the iterator snapshots the key ("nextKey") and
2241 <     * value ("nextVal") of a valid node (i.e., one that, at point of
2242 <     * snapshot, has a non-null user value). Because val fields can
2243 <     * change (including to null, indicating deletion), field nextVal
2244 <     * might not be accurate at point of use, but still maintains the
2245 <     * weak consistency property of holding a value that was once
2246 <     * valid.
2247 <     *
2248 <     * Internal traversals directly access these fields, as in:
2249 <     * {@code while (it.advance() != null) { process(it.nextKey); }}
2250 <     *
2251 <     * Exported iterators must track whether the iterator has advanced
2252 <     * (in hasNext vs next) (by setting/checking/nulling field
2253 <     * nextVal), and then extract key, value, or key-value pairs as
2254 <     * return values of next().
2255 <     *
2256 <     * The iterator visits once each still-valid node that was
2257 <     * reachable upon iterator construction. It might miss some that
2258 <     * were added to a bin after the bin was visited, which is OK wrt
2259 <     * consistency guarantees. Maintaining this property in the face
2260 <     * of possible ongoing resizes requires a fair amount of
2261 <     * bookkeeping state that is difficult to optimize away amidst
2262 <     * volatile accesses.  Even so, traversal maintains reasonable
2263 <     * throughput.
2264 <     *
2265 <     * Normally, iteration proceeds bin-by-bin traversing lists.
2266 <     * However, if the table has been resized, then all future steps
2267 <     * must traverse both the bin at the current index as well as at
2268 <     * (index + baseSize); and so on for further resizings. To
2269 <     * paranoically cope with potential sharing by users of iterators
2270 <     * across threads, iteration terminates if a bounds checks fails
2271 <     * for a table read.
2272 <     *
2273 <     * This class extends ForkJoinTask to streamline parallel
2274 <     * iteration in bulk operations (see BulkTask). This adds only an
2275 <     * int of space overhead, which is close enough to negligible in
2276 <     * cases where it is not needed to not worry about it.  Because
2277 <     * ForkJoinTask is Serializable, but iterators need not be, we
2278 <     * need to add warning suppressions.
2279 <     */
2280 <    @SuppressWarnings("serial") static class Traverser<K,V,R> extends ForkJoinTask<R> {
2281 <        final ConcurrentHashMapV8<K, V> map;
2282 <        Node next;           // the next entry to use
2283 <        Node last;           // the last entry used
2284 <        Object nextKey;      // cached key field of next
2285 <        Object nextVal;      // cached val field of next
2286 <        Node[] tab;          // current table; updated if resized
2287 <        int index;           // index of bin to use next
2288 <        int baseIndex;       // current index of initial table
2289 <        int baseLimit;       // index bound for initial table
2290 <        final int baseSize;  // initial table size
2291 <
2292 <        /** Creates iterator for all entries in the table. */
2293 <        Traverser(ConcurrentHashMapV8<K, V> map) {
2294 <            this.tab = (this.map = map).table;
2295 <            baseLimit = baseSize = (tab == null) ? 0 : tab.length;
2296 <        }
2297 <
2298 <        /** Creates iterator for split() methods */
2299 <        Traverser(Traverser<K,V,?> it) {
2300 <            this.map = it.map;
2301 <            this.tab = it.tab;
2302 <            this.baseSize = it.baseSize;
2303 <            it.baseLimit = this.index = this.baseIndex =
2304 <                ((this.baseLimit = it.baseLimit) + it.baseIndex + 1) >>> 1;
2305 <        }
782 >     * The next table index (plus one) to split while resizing.
783 >     */
784 >    private transient volatile int transferIndex;
785  
786 <        /**
787 <         * Advances next; returns nextVal or null if terminated.
788 <         * See above for explanation.
789 <         */
2311 <        final Object advance() {
2312 <            Node e = last = next;
2313 <            Object ev = null;
2314 <            outer: do {
2315 <                if (e != null)                  // advance past used/skipped node
2316 <                    e = e.next;
2317 <                while (e == null) {             // get to next non-null bin
2318 <                    Node[] t; int b, i, n; Object ek; // checks must use locals
2319 <                    if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2320 <                        (t = tab) == null || i >= (n = t.length))
2321 <                        break outer;
2322 <                    else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2323 <                        if ((ek = e.key) instanceof TreeBin)
2324 <                            e = ((TreeBin)ek).first;
2325 <                        else {
2326 <                            tab = (Node[])ek;
2327 <                            continue;           // restarts due to null val
2328 <                        }
2329 <                    }                           // visit upper slots if present
2330 <                    index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2331 <                }
2332 <                nextKey = e.key;
2333 <            } while ((ev = e.val) == null);    // skip deleted or special nodes
2334 <            next = e;
2335 <            return nextVal = ev;
2336 <        }
786 >    /**
787 >     * The least available table index to split while resizing.
788 >     */
789 >    private transient volatile int transferOrigin;
790  
791 <        public final void remove() {
792 <            if (nextVal == null && last == null)
793 <                advance();
794 <            Node e = last;
2342 <            if (e == null)
2343 <                throw new IllegalStateException();
2344 <            last = null;
2345 <            map.remove(e.key);
2346 <        }
791 >    /**
792 >     * Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
793 >     */
794 >    private transient volatile int cellsBusy;
795  
796 <        public final boolean hasNext() {
797 <            return nextVal != null || advance() != null;
798 <        }
796 >    /**
797 >     * Table of counter cells. When non-null, size is a power of 2.
798 >     */
799 >    private transient volatile CounterCell[] counterCells;
800 >
801 >    // views
802 >    private transient KeySetView<K,V> keySet;
803 >    private transient ValuesView<K,V> values;
804 >    private transient EntrySetView<K,V> entrySet;
805  
2352        public final boolean hasMoreElements() { return hasNext(); }
2353        public final void setRawResult(Object x) { }
2354        public R getRawResult() { return null; }
2355        public boolean exec() { return true; }
2356    }
806  
807      /* ---------------- Public operations -------------- */
808  
# Line 2361 | Line 810 | public class ConcurrentHashMapV8<K, V>
810       * Creates a new, empty map with the default initial table size (16).
811       */
812      public ConcurrentHashMapV8() {
2364        this.counter = new LongAdder();
813      }
814  
815      /**
# Line 2380 | Line 828 | public class ConcurrentHashMapV8<K, V>
828          int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
829                     MAXIMUM_CAPACITY :
830                     tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2383        this.counter = new LongAdder();
831          this.sizeCtl = cap;
832      }
833  
# Line 2390 | Line 837 | public class ConcurrentHashMapV8<K, V>
837       * @param m the map
838       */
839      public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2393        this.counter = new LongAdder();
840          this.sizeCtl = DEFAULT_CAPACITY;
841 <        internalPutAll(m);
841 >        putAll(m);
842      }
843  
844      /**
# Line 2433 | Line 879 | public class ConcurrentHashMapV8<K, V>
879       * nonpositive
880       */
881      public ConcurrentHashMapV8(int initialCapacity,
882 <                               float loadFactor, int concurrencyLevel) {
882 >                             float loadFactor, int concurrencyLevel) {
883          if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
884              throw new IllegalArgumentException();
885          if (initialCapacity < concurrencyLevel)   // Use at least as many bins
# Line 2441 | Line 887 | public class ConcurrentHashMapV8<K, V>
887          long size = (long)(1.0 + (long)initialCapacity / loadFactor);
888          int cap = (size >= (long)MAXIMUM_CAPACITY) ?
889              MAXIMUM_CAPACITY : tableSizeFor((int)size);
2444        this.counter = new LongAdder();
890          this.sizeCtl = cap;
891      }
892  
893 <    /**
2449 <     * {@inheritDoc}
2450 <     */
2451 <    public boolean isEmpty() {
2452 <        return counter.sum() <= 0L; // ignore transient negative values
2453 <    }
893 >    // Original (since JDK1.2) Map methods
894  
895      /**
896       * {@inheritDoc}
897       */
898      public int size() {
899 <        long n = counter.sum();
899 >        long n = sumCount();
900          return ((n < 0L) ? 0 :
901                  (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
902                  (int)n);
903      }
904  
905      /**
906 <     * Returns the number of mappings. This method should be used
2467 <     * instead of {@link #size} because a ConcurrentHashMap may
2468 <     * contain more mappings than can be represented as an int. The
2469 <     * value returned is a snapshot; the actual count may differ if
2470 <     * there are ongoing concurrent insertions or removals.
2471 <     *
2472 <     * @return the number of mappings
906 >     * {@inheritDoc}
907       */
908 <    public long mappingCount() {
909 <        long n = counter.sum();
2476 <        return (n < 0L) ? 0L : n; // ignore transient negative values
908 >    public boolean isEmpty() {
909 >        return sumCount() <= 0L; // ignore transient negative values
910      }
911  
912      /**
# Line 2487 | Line 920 | public class ConcurrentHashMapV8<K, V>
920       *
921       * @throws NullPointerException if the specified key is null
922       */
923 <    @SuppressWarnings("unchecked") public V get(Object key) {
924 <        if (key == null)
925 <            throw new NullPointerException();
926 <        return (V)internalGet(key);
923 >    public V get(Object key) {
924 >        Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
925 >        int h = spread(key.hashCode());
926 >        if ((tab = table) != null && (n = tab.length) > 0 &&
927 >            (e = tabAt(tab, (n - 1) & h)) != null) {
928 >            if ((eh = e.hash) == h) {
929 >                if ((ek = e.key) == key || (ek != null && key.equals(ek)))
930 >                    return e.val;
931 >            }
932 >            else if (eh < 0)
933 >                return (p = e.find(h, key)) != null ? p.val : null;
934 >            while ((e = e.next) != null) {
935 >                if (e.hash == h &&
936 >                    ((ek = e.key) == key || (ek != null && key.equals(ek))))
937 >                    return e.val;
938 >            }
939 >        }
940 >        return null;
941      }
942  
943      /**
944       * Tests if the specified object is a key in this table.
945       *
946 <     * @param  key   possible key
946 >     * @param  key possible key
947       * @return {@code true} if and only if the specified object
948       *         is a key in this table, as determined by the
949       *         {@code equals} method; {@code false} otherwise
950       * @throws NullPointerException if the specified key is null
951       */
952      public boolean containsKey(Object key) {
953 <        if (key == null)
2507 <            throw new NullPointerException();
2508 <        return internalGet(key) != null;
953 >        return get(key) != null;
954      }
955  
956      /**
# Line 2521 | Line 966 | public class ConcurrentHashMapV8<K, V>
966      public boolean containsValue(Object value) {
967          if (value == null)
968              throw new NullPointerException();
969 <        Object v;
970 <        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
971 <        while ((v = it.advance()) != null) {
972 <            if (v == value || value.equals(v))
973 <                return true;
969 >        Node<K,V>[] t;
970 >        if ((t = table) != null) {
971 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
972 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
973 >                V v;
974 >                if ((v = p.val) == value || (v != null && value.equals(v)))
975 >                    return true;
976 >            }
977          }
978          return false;
979      }
980  
981      /**
2534     * Legacy method testing if some key maps into the specified value
2535     * in this table.  This method is identical in functionality to
2536     * {@link #containsValue}, and exists solely to ensure
2537     * full compatibility with class {@link java.util.Hashtable},
2538     * which supported this method prior to introduction of the
2539     * Java Collections framework.
2540     *
2541     * @param  value a value to search for
2542     * @return {@code true} if and only if some key maps to the
2543     *         {@code value} argument in this table as
2544     *         determined by the {@code equals} method;
2545     *         {@code false} otherwise
2546     * @throws NullPointerException if the specified value is null
2547     */
2548    public boolean contains(Object value) {
2549        return containsValue(value);
2550    }
2551
2552    /**
982       * Maps the specified key to the specified value in this table.
983       * Neither the key nor the value can be null.
984       *
985 <     * <p> The value can be retrieved by calling the {@code get} method
985 >     * <p>The value can be retrieved by calling the {@code get} method
986       * with a key that is equal to the original key.
987       *
988       * @param key key with which the specified value is to be associated
# Line 2562 | Line 991 | public class ConcurrentHashMapV8<K, V>
991       *         {@code null} if there was no mapping for {@code key}
992       * @throws NullPointerException if the specified key or value is null
993       */
994 <    @SuppressWarnings("unchecked") public V put(K key, V value) {
995 <        if (key == null || value == null)
2567 <            throw new NullPointerException();
2568 <        return (V)internalPut(key, value);
994 >    public V put(K key, V value) {
995 >        return putVal(key, value, false);
996      }
997  
998 <    /**
999 <     * {@inheritDoc}
1000 <     *
1001 <     * @return the previous value associated with the specified key,
1002 <     *         or {@code null} if there was no mapping for the key
1003 <     * @throws NullPointerException if the specified key or value is null
1004 <     */
1005 <    @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
1006 <        if (key == null || value == null)
1007 <            throw new NullPointerException();
1008 <        return (V)internalPutIfAbsent(key, value);
998 >    /** Implementation for put and putIfAbsent */
999 >    final V putVal(K key, V value, boolean onlyIfAbsent) {
1000 >        if (key == null || value == null) throw new NullPointerException();
1001 >        int hash = spread(key.hashCode());
1002 >        int binCount = 0;
1003 >        for (Node<K,V>[] tab = table;;) {
1004 >            Node<K,V> f; int n, i, fh;
1005 >            if (tab == null || (n = tab.length) == 0)
1006 >                tab = initTable();
1007 >            else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
1008 >                if (casTabAt(tab, i, null,
1009 >                             new Node<K,V>(hash, key, value, null)))
1010 >                    break;                   // no lock when adding to empty bin
1011 >            }
1012 >            else if ((fh = f.hash) == MOVED)
1013 >                tab = helpTransfer(tab, f);
1014 >            else {
1015 >                V oldVal = null;
1016 >                synchronized (f) {
1017 >                    if (tabAt(tab, i) == f) {
1018 >                        if (fh >= 0) {
1019 >                            binCount = 1;
1020 >                            for (Node<K,V> e = f;; ++binCount) {
1021 >                                K ek;
1022 >                                if (e.hash == hash &&
1023 >                                    ((ek = e.key) == key ||
1024 >                                     (ek != null && key.equals(ek)))) {
1025 >                                    oldVal = e.val;
1026 >                                    if (!onlyIfAbsent)
1027 >                                        e.val = value;
1028 >                                    break;
1029 >                                }
1030 >                                Node<K,V> pred = e;
1031 >                                if ((e = e.next) == null) {
1032 >                                    pred.next = new Node<K,V>(hash, key,
1033 >                                                              value, null);
1034 >                                    break;
1035 >                                }
1036 >                            }
1037 >                        }
1038 >                        else if (f instanceof TreeBin) {
1039 >                            Node<K,V> p;
1040 >                            binCount = 2;
1041 >                            if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1042 >                                                           value)) != null) {
1043 >                                oldVal = p.val;
1044 >                                if (!onlyIfAbsent)
1045 >                                    p.val = value;
1046 >                            }
1047 >                        }
1048 >                    }
1049 >                }
1050 >                if (binCount != 0) {
1051 >                    if (binCount >= TREEIFY_THRESHOLD)
1052 >                        treeifyBin(tab, i);
1053 >                    if (oldVal != null)
1054 >                        return oldVal;
1055 >                    break;
1056 >                }
1057 >            }
1058 >        }
1059 >        addCount(1L, binCount);
1060 >        return null;
1061      }
1062  
1063      /**
# Line 2589 | Line 1068 | public class ConcurrentHashMapV8<K, V>
1068       * @param m mappings to be stored in this map
1069       */
1070      public void putAll(Map<? extends K, ? extends V> m) {
1071 <        internalPutAll(m);
1072 <    }
1073 <
2595 <    /**
2596 <     * If the specified key is not already associated with a value,
2597 <     * computes its value using the given mappingFunction and enters
2598 <     * it into the map unless null.  This is equivalent to
2599 <     * <pre> {@code
2600 <     * if (map.containsKey(key))
2601 <     *   return map.get(key);
2602 <     * value = mappingFunction.apply(key);
2603 <     * if (value != null)
2604 <     *   map.put(key, value);
2605 <     * return value;}</pre>
2606 <     *
2607 <     * except that the action is performed atomically.  If the
2608 <     * function returns {@code null} no mapping is recorded. If the
2609 <     * function itself throws an (unchecked) exception, the exception
2610 <     * is rethrown to its caller, and no mapping is recorded.  Some
2611 <     * attempted update operations on this map by other threads may be
2612 <     * blocked while computation is in progress, so the computation
2613 <     * should be short and simple, and must not attempt to update any
2614 <     * other mappings of this Map. The most appropriate usage is to
2615 <     * construct a new object serving as an initial mapped value, or
2616 <     * memoized result, as in:
2617 <     *
2618 <     *  <pre> {@code
2619 <     * map.computeIfAbsent(key, new Fun<K, V>() {
2620 <     *   public V map(K k) { return new Value(f(k)); }});}</pre>
2621 <     *
2622 <     * @param key key with which the specified value is to be associated
2623 <     * @param mappingFunction the function to compute a value
2624 <     * @return the current (existing or computed) value associated with
2625 <     *         the specified key, or null if the computed value is null.
2626 <     * @throws NullPointerException if the specified key or mappingFunction
2627 <     *         is null
2628 <     * @throws IllegalStateException if the computation detectably
2629 <     *         attempts a recursive update to this map that would
2630 <     *         otherwise never complete
2631 <     * @throws RuntimeException or Error if the mappingFunction does so,
2632 <     *         in which case the mapping is left unestablished
2633 <     */
2634 <    @SuppressWarnings("unchecked") public V computeIfAbsent
2635 <        (K key, Fun<? super K, ? extends V> mappingFunction) {
2636 <        if (key == null || mappingFunction == null)
2637 <            throw new NullPointerException();
2638 <        return (V)internalComputeIfAbsent(key, mappingFunction);
2639 <    }
2640 <
2641 <    /**
2642 <     * If the given key is present, computes a new mapping value given a key and
2643 <     * its current mapped value. This is equivalent to
2644 <     *  <pre> {@code
2645 <     *   if (map.containsKey(key)) {
2646 <     *     value = remappingFunction.apply(key, map.get(key));
2647 <     *     if (value != null)
2648 <     *       map.put(key, value);
2649 <     *     else
2650 <     *       map.remove(key);
2651 <     *   }
2652 <     * }</pre>
2653 <     *
2654 <     * except that the action is performed atomically.  If the
2655 <     * function returns {@code null}, the mapping is removed.  If the
2656 <     * function itself throws an (unchecked) exception, the exception
2657 <     * is rethrown to its caller, and the current mapping is left
2658 <     * unchanged.  Some attempted update operations on this map by
2659 <     * other threads may be blocked while computation is in progress,
2660 <     * so the computation should be short and simple, and must not
2661 <     * attempt to update any other mappings of this Map. For example,
2662 <     * to either create or append new messages to a value mapping:
2663 <     *
2664 <     * @param key key with which the specified value is to be associated
2665 <     * @param remappingFunction the function to compute a value
2666 <     * @return the new value associated with the specified key, or null if none
2667 <     * @throws NullPointerException if the specified key or remappingFunction
2668 <     *         is null
2669 <     * @throws IllegalStateException if the computation detectably
2670 <     *         attempts a recursive update to this map that would
2671 <     *         otherwise never complete
2672 <     * @throws RuntimeException or Error if the remappingFunction does so,
2673 <     *         in which case the mapping is unchanged
2674 <     */
2675 <    @SuppressWarnings("unchecked") public V computeIfPresent
2676 <        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2677 <        if (key == null || remappingFunction == null)
2678 <            throw new NullPointerException();
2679 <        return (V)internalCompute(key, true, remappingFunction);
2680 <    }
2681 <
2682 <    /**
2683 <     * Computes a new mapping value given a key and
2684 <     * its current mapped value (or {@code null} if there is no current
2685 <     * mapping). This is equivalent to
2686 <     *  <pre> {@code
2687 <     *   value = remappingFunction.apply(key, map.get(key));
2688 <     *   if (value != null)
2689 <     *     map.put(key, value);
2690 <     *   else
2691 <     *     map.remove(key);
2692 <     * }</pre>
2693 <     *
2694 <     * except that the action is performed atomically.  If the
2695 <     * function returns {@code null}, the mapping is removed.  If the
2696 <     * function itself throws an (unchecked) exception, the exception
2697 <     * is rethrown to its caller, and the current mapping is left
2698 <     * unchanged.  Some attempted update operations on this map by
2699 <     * other threads may be blocked while computation is in progress,
2700 <     * so the computation should be short and simple, and must not
2701 <     * attempt to update any other mappings of this Map. For example,
2702 <     * to either create or append new messages to a value mapping:
2703 <     *
2704 <     * <pre> {@code
2705 <     * Map<Key, String> map = ...;
2706 <     * final String msg = ...;
2707 <     * map.compute(key, new BiFun<Key, String, String>() {
2708 <     *   public String apply(Key k, String v) {
2709 <     *    return (v == null) ? msg : v + msg;});}}</pre>
2710 <     *
2711 <     * @param key key with which the specified value is to be associated
2712 <     * @param remappingFunction the function to compute a value
2713 <     * @return the new value associated with the specified key, or null if none
2714 <     * @throws NullPointerException if the specified key or remappingFunction
2715 <     *         is null
2716 <     * @throws IllegalStateException if the computation detectably
2717 <     *         attempts a recursive update to this map that would
2718 <     *         otherwise never complete
2719 <     * @throws RuntimeException or Error if the remappingFunction does so,
2720 <     *         in which case the mapping is unchanged
2721 <     */
2722 <    @SuppressWarnings("unchecked") public V compute
2723 <        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2724 <        if (key == null || remappingFunction == null)
2725 <            throw new NullPointerException();
2726 <        return (V)internalCompute(key, false, remappingFunction);
2727 <    }
2728 <
2729 <    /**
2730 <     * If the specified key is not already associated
2731 <     * with a value, associate it with the given value.
2732 <     * Otherwise, replace the value with the results of
2733 <     * the given remapping function. This is equivalent to:
2734 <     *  <pre> {@code
2735 <     *   if (!map.containsKey(key))
2736 <     *     map.put(value);
2737 <     *   else {
2738 <     *     newValue = remappingFunction.apply(map.get(key), value);
2739 <     *     if (value != null)
2740 <     *       map.put(key, value);
2741 <     *     else
2742 <     *       map.remove(key);
2743 <     *   }
2744 <     * }</pre>
2745 <     * except that the action is performed atomically.  If the
2746 <     * function returns {@code null}, the mapping is removed.  If the
2747 <     * function itself throws an (unchecked) exception, the exception
2748 <     * is rethrown to its caller, and the current mapping is left
2749 <     * unchanged.  Some attempted update operations on this map by
2750 <     * other threads may be blocked while computation is in progress,
2751 <     * so the computation should be short and simple, and must not
2752 <     * attempt to update any other mappings of this Map.
2753 <     */
2754 <    @SuppressWarnings("unchecked") public V merge
2755 <        (K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
2756 <        if (key == null || value == null || remappingFunction == null)
2757 <            throw new NullPointerException();
2758 <        return (V)internalMerge(key, value, remappingFunction);
1071 >        tryPresize(m.size());
1072 >        for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1073 >            putVal(e.getKey(), e.getValue(), false);
1074      }
1075  
1076      /**
# Line 2767 | Line 1082 | public class ConcurrentHashMapV8<K, V>
1082       *         {@code null} if there was no mapping for {@code key}
1083       * @throws NullPointerException if the specified key is null
1084       */
1085 <    @SuppressWarnings("unchecked") public V remove(Object key) {
1086 <        if (key == null)
2772 <            throw new NullPointerException();
2773 <        return (V)internalReplace(key, null, null);
1085 >    public V remove(Object key) {
1086 >        return replaceNode(key, null, null);
1087      }
1088  
1089      /**
1090 <     * {@inheritDoc}
1091 <     *
1092 <     * @throws NullPointerException if the specified key is null
2780 <     */
2781 <    public boolean remove(Object key, Object value) {
2782 <        if (key == null)
2783 <            throw new NullPointerException();
2784 <        if (value == null)
2785 <            return false;
2786 <        return internalReplace(key, null, value) != null;
2787 <    }
2788 <
2789 <    /**
2790 <     * {@inheritDoc}
2791 <     *
2792 <     * @throws NullPointerException if any of the arguments are null
2793 <     */
2794 <    public boolean replace(K key, V oldValue, V newValue) {
2795 <        if (key == null || oldValue == null || newValue == null)
2796 <            throw new NullPointerException();
2797 <        return internalReplace(key, newValue, oldValue) != null;
2798 <    }
2799 <
2800 <    /**
2801 <     * {@inheritDoc}
2802 <     *
2803 <     * @return the previous value associated with the specified key,
2804 <     *         or {@code null} if there was no mapping for the key
2805 <     * @throws NullPointerException if the specified key or value is null
1090 >     * Implementation for the four public remove/replace methods:
1091 >     * Replaces node value with v, conditional upon match of cv if
1092 >     * non-null.  If resulting value is null, delete.
1093       */
1094 <    @SuppressWarnings("unchecked") public V replace(K key, V value) {
1095 <        if (key == null || value == null)
1096 <            throw new NullPointerException();
1097 <        return (V)internalReplace(key, value, null);
1094 >    final V replaceNode(Object key, V value, Object cv) {
1095 >        int hash = spread(key.hashCode());
1096 >        for (Node<K,V>[] tab = table;;) {
1097 >            Node<K,V> f; int n, i, fh;
1098 >            if (tab == null || (n = tab.length) == 0 ||
1099 >                (f = tabAt(tab, i = (n - 1) & hash)) == null)
1100 >                break;
1101 >            else if ((fh = f.hash) == MOVED)
1102 >                tab = helpTransfer(tab, f);
1103 >            else {
1104 >                V oldVal = null;
1105 >                boolean validated = false;
1106 >                synchronized (f) {
1107 >                    if (tabAt(tab, i) == f) {
1108 >                        if (fh >= 0) {
1109 >                            validated = true;
1110 >                            for (Node<K,V> e = f, pred = null;;) {
1111 >                                K ek;
1112 >                                if (e.hash == hash &&
1113 >                                    ((ek = e.key) == key ||
1114 >                                     (ek != null && key.equals(ek)))) {
1115 >                                    V ev = e.val;
1116 >                                    if (cv == null || cv == ev ||
1117 >                                        (ev != null && cv.equals(ev))) {
1118 >                                        oldVal = ev;
1119 >                                        if (value != null)
1120 >                                            e.val = value;
1121 >                                        else if (pred != null)
1122 >                                            pred.next = e.next;
1123 >                                        else
1124 >                                            setTabAt(tab, i, e.next);
1125 >                                    }
1126 >                                    break;
1127 >                                }
1128 >                                pred = e;
1129 >                                if ((e = e.next) == null)
1130 >                                    break;
1131 >                            }
1132 >                        }
1133 >                        else if (f instanceof TreeBin) {
1134 >                            validated = true;
1135 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1136 >                            TreeNode<K,V> r, p;
1137 >                            if ((r = t.root) != null &&
1138 >                                (p = r.findTreeNode(hash, key, null)) != null) {
1139 >                                V pv = p.val;
1140 >                                if (cv == null || cv == pv ||
1141 >                                    (pv != null && cv.equals(pv))) {
1142 >                                    oldVal = pv;
1143 >                                    if (value != null)
1144 >                                        p.val = value;
1145 >                                    else if (t.removeTreeNode(p))
1146 >                                        setTabAt(tab, i, untreeify(t.first));
1147 >                                }
1148 >                            }
1149 >                        }
1150 >                    }
1151 >                }
1152 >                if (validated) {
1153 >                    if (oldVal != null) {
1154 >                        if (value == null)
1155 >                            addCount(-1L, -1);
1156 >                        return oldVal;
1157 >                    }
1158 >                    break;
1159 >                }
1160 >            }
1161 >        }
1162 >        return null;
1163      }
1164  
1165      /**
1166       * Removes all of the mappings from this map.
1167       */
1168      public void clear() {
1169 <        internalClear();
1169 >        long delta = 0L; // negative number of deletions
1170 >        int i = 0;
1171 >        Node<K,V>[] tab = table;
1172 >        while (tab != null && i < tab.length) {
1173 >            int fh;
1174 >            Node<K,V> f = tabAt(tab, i);
1175 >            if (f == null)
1176 >                ++i;
1177 >            else if ((fh = f.hash) == MOVED) {
1178 >                tab = helpTransfer(tab, f);
1179 >                i = 0; // restart
1180 >            }
1181 >            else {
1182 >                synchronized (f) {
1183 >                    if (tabAt(tab, i) == f) {
1184 >                        Node<K,V> p = (fh >= 0 ? f :
1185 >                                       (f instanceof TreeBin) ?
1186 >                                       ((TreeBin<K,V>)f).first : null);
1187 >                        while (p != null) {
1188 >                            --delta;
1189 >                            p = p.next;
1190 >                        }
1191 >                        setTabAt(tab, i++, null);
1192 >                    }
1193 >                }
1194 >            }
1195 >        }
1196 >        if (delta != 0L)
1197 >            addCount(delta, -1);
1198      }
1199  
1200      /**
1201       * Returns a {@link Set} view of the keys contained in this map.
1202       * The set is backed by the map, so changes to the map are
1203 <     * reflected in the set, and vice-versa.  The set supports element
1203 >     * reflected in the set, and vice-versa. The set supports element
1204       * removal, which removes the corresponding mapping from this map,
1205       * via the {@code Iterator.remove}, {@code Set.remove},
1206       * {@code removeAll}, {@code retainAll}, and {@code clear}
# Line 2832 | Line 1212 | public class ConcurrentHashMapV8<K, V>
1212       * and guarantees to traverse elements as they existed upon
1213       * construction of the iterator, and may (but is not guaranteed to)
1214       * reflect any modifications subsequent to construction.
1215 +     *
1216 +     * @return the set view
1217       */
1218 <    public Set<K> keySet() {
1219 <        KeySet<K,V> ks = keySet;
1220 <        return (ks != null) ? ks : (keySet = new KeySet<K,V>(this));
1218 >    public KeySetView<K,V> keySet() {
1219 >        KeySetView<K,V> ks;
1220 >        return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1221      }
1222  
1223      /**
# Line 2853 | Line 1235 | public class ConcurrentHashMapV8<K, V>
1235       * and guarantees to traverse elements as they existed upon
1236       * construction of the iterator, and may (but is not guaranteed to)
1237       * reflect any modifications subsequent to construction.
1238 +     *
1239 +     * @return the collection view
1240       */
1241      public Collection<V> values() {
1242 <        Values<K,V> vs = values;
1243 <        return (vs != null) ? vs : (values = new Values<K,V>(this));
1242 >        ValuesView<K,V> vs;
1243 >        return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1244      }
1245  
1246      /**
# Line 2866 | Line 1250 | public class ConcurrentHashMapV8<K, V>
1250       * removal, which removes the corresponding mapping from the map,
1251       * via the {@code Iterator.remove}, {@code Set.remove},
1252       * {@code removeAll}, {@code retainAll}, and {@code clear}
1253 <     * operations.  It does not support the {@code add} or
2870 <     * {@code addAll} operations.
1253 >     * operations.
1254       *
1255       * <p>The view's {@code iterator} is a "weakly consistent" iterator
1256       * that will never throw {@link ConcurrentModificationException},
1257       * and guarantees to traverse elements as they existed upon
1258       * construction of the iterator, and may (but is not guaranteed to)
1259       * reflect any modifications subsequent to construction.
2877     */
2878    public Set<Map.Entry<K,V>> entrySet() {
2879        EntrySet<K,V> es = entrySet;
2880        return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
2881    }
2882
2883    /**
2884     * Returns an enumeration of the keys in this table.
2885     *
2886     * @return an enumeration of the keys in this table
2887     * @see #keySet()
2888     */
2889    public Enumeration<K> keys() {
2890        return new KeyIterator<K,V>(this);
2891    }
2892
2893    /**
2894     * Returns an enumeration of the values in this table.
1260       *
1261 <     * @return an enumeration of the values in this table
2897 <     * @see #values()
1261 >     * @return the set view
1262       */
1263 <    public Enumeration<V> elements() {
1264 <        return new ValueIterator<K,V>(this);
1265 <    }
2902 <
2903 <    /**
2904 <     * Returns a partitionable iterator of the keys in this map.
2905 <     *
2906 <     * @return a partitionable iterator of the keys in this map
2907 <     */
2908 <    public Spliterator<K> keySpliterator() {
2909 <        return new KeyIterator<K,V>(this);
2910 <    }
2911 <
2912 <    /**
2913 <     * Returns a partitionable iterator of the values in this map.
2914 <     *
2915 <     * @return a partitionable iterator of the values in this map
2916 <     */
2917 <    public Spliterator<V> valueSpliterator() {
2918 <        return new ValueIterator<K,V>(this);
2919 <    }
2920 <
2921 <    /**
2922 <     * Returns a partitionable iterator of the entries in this map.
2923 <     *
2924 <     * @return a partitionable iterator of the entries in this map
2925 <     */
2926 <    public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2927 <        return new EntryIterator<K,V>(this);
1263 >    public Set<Map.Entry<K,V>> entrySet() {
1264 >        EntrySetView<K,V> es;
1265 >        return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1266      }
1267  
1268      /**
# Line 2936 | Line 1274 | public class ConcurrentHashMapV8<K, V>
1274       */
1275      public int hashCode() {
1276          int h = 0;
1277 <        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
1278 <        Object v;
1279 <        while ((v = it.advance()) != null) {
1280 <            h += it.nextKey.hashCode() ^ v.hashCode();
1277 >        Node<K,V>[] t;
1278 >        if ((t = table) != null) {
1279 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1280 >            for (Node<K,V> p; (p = it.advance()) != null; )
1281 >                h += p.key.hashCode() ^ p.val.hashCode();
1282          }
1283          return h;
1284      }
# Line 2956 | Line 1295 | public class ConcurrentHashMapV8<K, V>
1295       * @return a string representation of this map
1296       */
1297      public String toString() {
1298 <        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
1298 >        Node<K,V>[] t;
1299 >        int f = (t = table) == null ? 0 : t.length;
1300 >        Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1301          StringBuilder sb = new StringBuilder();
1302          sb.append('{');
1303 <        Object v;
1304 <        if ((v = it.advance()) != null) {
1303 >        Node<K,V> p;
1304 >        if ((p = it.advance()) != null) {
1305              for (;;) {
1306 <                Object k = it.nextKey;
1306 >                K k = p.key;
1307 >                V v = p.val;
1308                  sb.append(k == this ? "(this Map)" : k);
1309                  sb.append('=');
1310                  sb.append(v == this ? "(this Map)" : v);
1311 <                if ((v = it.advance()) == null)
1311 >                if ((p = it.advance()) == null)
1312                      break;
1313                  sb.append(',').append(' ');
1314              }
# Line 2989 | Line 1331 | public class ConcurrentHashMapV8<K, V>
1331              if (!(o instanceof Map))
1332                  return false;
1333              Map<?,?> m = (Map<?,?>) o;
1334 <            Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
1335 <            Object val;
1336 <            while ((val = it.advance()) != null) {
1337 <                Object v = m.get(it.nextKey);
1334 >            Node<K,V>[] t;
1335 >            int f = (t = table) == null ? 0 : t.length;
1336 >            Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1337 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1338 >                V val = p.val;
1339 >                Object v = m.get(p.key);
1340                  if (v == null || (v != val && !v.equals(val)))
1341                      return false;
1342              }
# Line 3000 | Line 1344 | public class ConcurrentHashMapV8<K, V>
1344                  Object mk, mv, v;
1345                  if ((mk = e.getKey()) == null ||
1346                      (mv = e.getValue()) == null ||
1347 <                    (v = internalGet(mk)) == null ||
1347 >                    (v = get(mk)) == null ||
1348                      (mv != v && !mv.equals(v)))
1349                      return false;
1350              }
# Line 3008 | Line 1352 | public class ConcurrentHashMapV8<K, V>
1352          return true;
1353      }
1354  
1355 <    /* ----------------Iterators -------------- */
1355 >    /**
1356 >     * Stripped-down version of helper class used in previous version,
1357 >     * declared for the sake of serialization compatibility
1358 >     */
1359 >    static class Segment<K,V> extends ReentrantLock implements Serializable {
1360 >        private static final long serialVersionUID = 2249069246763182397L;
1361 >        final float loadFactor;
1362 >        Segment(float lf) { this.loadFactor = lf; }
1363 >    }
1364  
1365 <    @SuppressWarnings("serial") static final class KeyIterator<K,V> extends Traverser<K,V,Object>
1366 <        implements Spliterator<K>, Enumeration<K> {
1367 <        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1368 <        KeyIterator(Traverser<K,V,Object> it) {
1369 <            super(it);
1370 <        }
1371 <        public KeyIterator<K,V> split() {
1372 <            if (last != null || (next != null && nextVal == null))
1373 <                throw new IllegalStateException();
1374 <            return new KeyIterator<K,V>(this);
1375 <        }
1376 <        @SuppressWarnings("unchecked") public final K next() {
1377 <            if (nextVal == null && advance() == null)
1378 <                throw new NoSuchElementException();
1379 <            Object k = nextKey;
1380 <            nextVal = null;
1381 <            return (K) k;
1365 >    /**
1366 >     * Saves the state of the {@code ConcurrentHashMapV8} instance to a
1367 >     * stream (i.e., serializes it).
1368 >     * @param s the stream
1369 >     * @serialData
1370 >     * the key (Object) and value (Object)
1371 >     * for each key-value mapping, followed by a null pair.
1372 >     * The key-value mappings are emitted in no particular order.
1373 >     */
1374 >    private void writeObject(java.io.ObjectOutputStream s)
1375 >        throws java.io.IOException {
1376 >        // For serialization compatibility
1377 >        // Emulate segment calculation from previous version of this class
1378 >        int sshift = 0;
1379 >        int ssize = 1;
1380 >        while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1381 >            ++sshift;
1382 >            ssize <<= 1;
1383 >        }
1384 >        int segmentShift = 32 - sshift;
1385 >        int segmentMask = ssize - 1;
1386 >        @SuppressWarnings("unchecked") Segment<K,V>[] segments = (Segment<K,V>[])
1387 >            new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1388 >        for (int i = 0; i < segments.length; ++i)
1389 >            segments[i] = new Segment<K,V>(LOAD_FACTOR);
1390 >        s.putFields().put("segments", segments);
1391 >        s.putFields().put("segmentShift", segmentShift);
1392 >        s.putFields().put("segmentMask", segmentMask);
1393 >        s.writeFields();
1394 >
1395 >        Node<K,V>[] t;
1396 >        if ((t = table) != null) {
1397 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1398 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1399 >                s.writeObject(p.key);
1400 >                s.writeObject(p.val);
1401 >            }
1402          }
1403 <
1404 <        public final K nextElement() { return next(); }
1403 >        s.writeObject(null);
1404 >        s.writeObject(null);
1405 >        segments = null; // throw away
1406      }
1407  
1408 <    @SuppressWarnings("serial") static final class ValueIterator<K,V> extends Traverser<K,V,Object>
1409 <        implements Spliterator<V>, Enumeration<V> {
1410 <        ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1411 <        ValueIterator(Traverser<K,V,Object> it) {
1412 <            super(it);
1413 <        }
1414 <        public ValueIterator<K,V> split() {
1415 <            if (last != null || (next != null && nextVal == null))
1416 <                throw new IllegalStateException();
1417 <            return new ValueIterator<K,V>(this);
1408 >    /**
1409 >     * Reconstitutes the instance from a stream (that is, deserializes it).
1410 >     * @param s the stream
1411 >     */
1412 >    private void readObject(java.io.ObjectInputStream s)
1413 >        throws java.io.IOException, ClassNotFoundException {
1414 >        /*
1415 >         * To improve performance in typical cases, we create nodes
1416 >         * while reading, then place in table once size is known.
1417 >         * However, we must also validate uniqueness and deal with
1418 >         * overpopulated bins while doing so, which requires
1419 >         * specialized versions of putVal mechanics.
1420 >         */
1421 >        sizeCtl = -1; // force exclusion for table construction
1422 >        s.defaultReadObject();
1423 >        long size = 0L;
1424 >        Node<K,V> p = null;
1425 >        for (;;) {
1426 >            @SuppressWarnings("unchecked") K k = (K) s.readObject();
1427 >            @SuppressWarnings("unchecked") V v = (V) s.readObject();
1428 >            if (k != null && v != null) {
1429 >                p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1430 >                ++size;
1431 >            }
1432 >            else
1433 >                break;
1434          }
1435 <
1436 <        @SuppressWarnings("unchecked") public final V next() {
1437 <            Object v;
1438 <            if ((v = nextVal) == null && (v = advance()) == null)
1439 <                throw new NoSuchElementException();
1440 <            nextVal = null;
1441 <            return (V) v;
1435 >        if (size == 0L)
1436 >            sizeCtl = 0;
1437 >        else {
1438 >            int n;
1439 >            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1440 >                n = MAXIMUM_CAPACITY;
1441 >            else {
1442 >                int sz = (int)size;
1443 >                n = tableSizeFor(sz + (sz >>> 1) + 1);
1444 >            }
1445 >            @SuppressWarnings({"rawtypes","unchecked"})
1446 >                Node<K,V>[] tab = (Node<K,V>[])new Node[n];
1447 >            int mask = n - 1;
1448 >            long added = 0L;
1449 >            while (p != null) {
1450 >                boolean insertAtFront;
1451 >                Node<K,V> next = p.next, first;
1452 >                int h = p.hash, j = h & mask;
1453 >                if ((first = tabAt(tab, j)) == null)
1454 >                    insertAtFront = true;
1455 >                else {
1456 >                    K k = p.key;
1457 >                    if (first.hash < 0) {
1458 >                        TreeBin<K,V> t = (TreeBin<K,V>)first;
1459 >                        if (t.putTreeVal(h, k, p.val) == null)
1460 >                            ++added;
1461 >                        insertAtFront = false;
1462 >                    }
1463 >                    else {
1464 >                        int binCount = 0;
1465 >                        insertAtFront = true;
1466 >                        Node<K,V> q; K qk;
1467 >                        for (q = first; q != null; q = q.next) {
1468 >                            if (q.hash == h &&
1469 >                                ((qk = q.key) == k ||
1470 >                                 (qk != null && k.equals(qk)))) {
1471 >                                insertAtFront = false;
1472 >                                break;
1473 >                            }
1474 >                            ++binCount;
1475 >                        }
1476 >                        if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1477 >                            insertAtFront = false;
1478 >                            ++added;
1479 >                            p.next = first;
1480 >                            TreeNode<K,V> hd = null, tl = null;
1481 >                            for (q = p; q != null; q = q.next) {
1482 >                                TreeNode<K,V> t = new TreeNode<K,V>
1483 >                                    (q.hash, q.key, q.val, null, null);
1484 >                                if ((t.prev = tl) == null)
1485 >                                    hd = t;
1486 >                                else
1487 >                                    tl.next = t;
1488 >                                tl = t;
1489 >                            }
1490 >                            setTabAt(tab, j, new TreeBin<K,V>(hd));
1491 >                        }
1492 >                    }
1493 >                }
1494 >                if (insertAtFront) {
1495 >                    ++added;
1496 >                    p.next = first;
1497 >                    setTabAt(tab, j, p);
1498 >                }
1499 >                p = next;
1500 >            }
1501 >            table = tab;
1502 >            sizeCtl = n - (n >>> 2);
1503 >            baseCount = added;
1504          }
3054
3055        public final V nextElement() { return next(); }
1505      }
1506  
1507 <    @SuppressWarnings("serial") static final class EntryIterator<K,V> extends Traverser<K,V,Object>
3059 <        implements Spliterator<Map.Entry<K,V>> {
3060 <        EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3061 <        EntryIterator(Traverser<K,V,Object> it) {
3062 <            super(it);
3063 <        }
3064 <        public EntryIterator<K,V> split() {
3065 <            if (last != null || (next != null && nextVal == null))
3066 <                throw new IllegalStateException();
3067 <            return new EntryIterator<K,V>(this);
3068 <        }
1507 >    // ConcurrentMap methods
1508  
1509 <        @SuppressWarnings("unchecked") public final Map.Entry<K,V> next() {
1510 <            Object v;
1511 <            if ((v = nextVal) == null && (v = advance()) == null)
1512 <                throw new NoSuchElementException();
1513 <            Object k = nextKey;
1514 <            nextVal = null;
1515 <            return new MapEntry<K,V>((K)k, (V)v, map);
1516 <        }
1509 >    /**
1510 >     * {@inheritDoc}
1511 >     *
1512 >     * @return the previous value associated with the specified key,
1513 >     *         or {@code null} if there was no mapping for the key
1514 >     * @throws NullPointerException if the specified key or value is null
1515 >     */
1516 >    public V putIfAbsent(K key, V value) {
1517 >        return putVal(key, value, true);
1518      }
1519  
1520      /**
1521 <     * Exported Entry for iterators
1521 >     * {@inheritDoc}
1522 >     *
1523 >     * @throws NullPointerException if the specified key is null
1524       */
1525 <    static final class MapEntry<K,V> implements Map.Entry<K, V> {
1526 <        final K key; // non-null
1527 <        V val;       // non-null
1528 <        final ConcurrentHashMapV8<K, V> map;
3087 <        MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
3088 <            this.key = key;
3089 <            this.val = val;
3090 <            this.map = map;
3091 <        }
3092 <        public final K getKey()       { return key; }
3093 <        public final V getValue()     { return val; }
3094 <        public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3095 <        public final String toString(){ return key + "=" + val; }
3096 <
3097 <        public final boolean equals(Object o) {
3098 <            Object k, v; Map.Entry<?,?> e;
3099 <            return ((o instanceof Map.Entry) &&
3100 <                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3101 <                    (v = e.getValue()) != null &&
3102 <                    (k == key || k.equals(key)) &&
3103 <                    (v == val || v.equals(val)));
3104 <        }
3105 <
3106 <        /**
3107 <         * Sets our entry's value and writes through to the map. The
3108 <         * value to return is somewhat arbitrary here. Since we do not
3109 <         * necessarily track asynchronous changes, the most recent
3110 <         * "previous" value could be different from what we return (or
3111 <         * could even have been removed in which case the put will
3112 <         * re-establish). We do not and cannot guarantee more.
3113 <         */
3114 <        public final V setValue(V value) {
3115 <            if (value == null) throw new NullPointerException();
3116 <            V v = val;
3117 <            val = value;
3118 <            map.put(key, value);
3119 <            return v;
3120 <        }
1525 >    public boolean remove(Object key, Object value) {
1526 >        if (key == null)
1527 >            throw new NullPointerException();
1528 >        return value != null && replaceNode(key, null, value) != null;
1529      }
1530  
1531 <    /* ----------------Views -------------- */
1531 >    /**
1532 >     * {@inheritDoc}
1533 >     *
1534 >     * @throws NullPointerException if any of the arguments are null
1535 >     */
1536 >    public boolean replace(K key, V oldValue, V newValue) {
1537 >        if (key == null || oldValue == null || newValue == null)
1538 >            throw new NullPointerException();
1539 >        return replaceNode(key, newValue, oldValue) != null;
1540 >    }
1541  
1542      /**
1543 <     * Base class for views.
1543 >     * {@inheritDoc}
1544 >     *
1545 >     * @return the previous value associated with the specified key,
1546 >     *         or {@code null} if there was no mapping for the key
1547 >     * @throws NullPointerException if the specified key or value is null
1548       */
1549 <    static abstract class CHMView<K, V> {
1550 <        final ConcurrentHashMapV8<K, V> map;
1551 <        CHMView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
1552 <        public final int size()                 { return map.size(); }
1553 <        public final boolean isEmpty()          { return map.isEmpty(); }
3133 <        public final void clear()               { map.clear(); }
1549 >    public V replace(K key, V value) {
1550 >        if (key == null || value == null)
1551 >            throw new NullPointerException();
1552 >        return replaceNode(key, value, null);
1553 >    }
1554  
1555 <        // implementations below rely on concrete classes supplying these
3136 <        abstract public Iterator<?> iterator();
3137 <        abstract public boolean contains(Object o);
3138 <        abstract public boolean remove(Object o);
1555 >    // Overrides of JDK8+ Map extension method defaults
1556  
1557 <        private static final String oomeMsg = "Required array size too large";
1557 >    /**
1558 >     * Returns the value to which the specified key is mapped, or the
1559 >     * given default value if this map contains no mapping for the
1560 >     * key.
1561 >     *
1562 >     * @param key the key whose associated value is to be returned
1563 >     * @param defaultValue the value to return if this map contains
1564 >     * no mapping for the given key
1565 >     * @return the mapping for the key, if present; else the default value
1566 >     * @throws NullPointerException if the specified key is null
1567 >     */
1568 >    public V getOrDefault(Object key, V defaultValue) {
1569 >        V v;
1570 >        return (v = get(key)) == null ? defaultValue : v;
1571 >    }
1572 >
1573 >    public void forEach(BiAction<? super K, ? super V> action) {
1574 >        if (action == null) throw new NullPointerException();
1575 >        Node<K,V>[] t;
1576 >        if ((t = table) != null) {
1577 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1578 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1579 >                action.apply(p.key, p.val);
1580 >            }
1581 >        }
1582 >    }
1583  
1584 <        public final Object[] toArray() {
1585 <            long sz = map.mappingCount();
1586 <            if (sz > (long)(MAX_ARRAY_SIZE))
1587 <                throw new OutOfMemoryError(oomeMsg);
1588 <            int n = (int)sz;
1589 <            Object[] r = new Object[n];
1590 <            int i = 0;
1591 <            Iterator<?> it = iterator();
1592 <            while (it.hasNext()) {
1593 <                if (i == n) {
1594 <                    if (n >= MAX_ARRAY_SIZE)
1595 <                        throw new OutOfMemoryError(oomeMsg);
1596 <                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
1597 <                        n = MAX_ARRAY_SIZE;
3156 <                    else
3157 <                        n += (n >>> 1) + 1;
3158 <                    r = Arrays.copyOf(r, n);
1584 >    public void replaceAll(BiFun<? super K, ? super V, ? extends V> function) {
1585 >        if (function == null) throw new NullPointerException();
1586 >        Node<K,V>[] t;
1587 >        if ((t = table) != null) {
1588 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1589 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1590 >                V oldValue = p.val;
1591 >                for (K key = p.key;;) {
1592 >                    V newValue = function.apply(key, oldValue);
1593 >                    if (newValue == null)
1594 >                        throw new NullPointerException();
1595 >                    if (replaceNode(key, newValue, oldValue) != null ||
1596 >                        (oldValue = get(key)) == null)
1597 >                        break;
1598                  }
3160                r[i++] = it.next();
1599              }
3162            return (i == n) ? r : Arrays.copyOf(r, i);
1600          }
1601 +    }
1602  
1603 <        @SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
1604 <            long sz = map.mappingCount();
1605 <            if (sz > (long)(MAX_ARRAY_SIZE))
1606 <                throw new OutOfMemoryError(oomeMsg);
1607 <            int m = (int)sz;
1608 <            T[] r = (a.length >= m) ? a :
1609 <                (T[])java.lang.reflect.Array
1610 <                .newInstance(a.getClass().getComponentType(), m);
1611 <            int n = r.length;
1612 <            int i = 0;
1613 <            Iterator<?> it = iterator();
1614 <            while (it.hasNext()) {
1615 <                if (i == n) {
1616 <                    if (n >= MAX_ARRAY_SIZE)
1617 <                        throw new OutOfMemoryError(oomeMsg);
1618 <                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
1619 <                        n = MAX_ARRAY_SIZE;
1620 <                    else
1621 <                        n += (n >>> 1) + 1;
1622 <                    r = Arrays.copyOf(r, n);
1603 >    /**
1604 >     * If the specified key is not already associated with a value,
1605 >     * attempts to compute its value using the given mapping function
1606 >     * and enters it into this map unless {@code null}.  The entire
1607 >     * method invocation is performed atomically, so the function is
1608 >     * applied at most once per key.  Some attempted update operations
1609 >     * on this map by other threads may be blocked while computation
1610 >     * is in progress, so the computation should be short and simple,
1611 >     * and must not attempt to update any other mappings of this map.
1612 >     *
1613 >     * @param key key with which the specified value is to be associated
1614 >     * @param mappingFunction the function to compute a value
1615 >     * @return the current (existing or computed) value associated with
1616 >     *         the specified key, or null if the computed value is null
1617 >     * @throws NullPointerException if the specified key or mappingFunction
1618 >     *         is null
1619 >     * @throws IllegalStateException if the computation detectably
1620 >     *         attempts a recursive update to this map that would
1621 >     *         otherwise never complete
1622 >     * @throws RuntimeException or Error if the mappingFunction does so,
1623 >     *         in which case the mapping is left unestablished
1624 >     */
1625 >    public V computeIfAbsent(K key, Fun<? super K, ? extends V> mappingFunction) {
1626 >        if (key == null || mappingFunction == null)
1627 >            throw new NullPointerException();
1628 >        int h = spread(key.hashCode());
1629 >        V val = null;
1630 >        int binCount = 0;
1631 >        for (Node<K,V>[] tab = table;;) {
1632 >            Node<K,V> f; int n, i, fh;
1633 >            if (tab == null || (n = tab.length) == 0)
1634 >                tab = initTable();
1635 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1636 >                Node<K,V> r = new ReservationNode<K,V>();
1637 >                synchronized (r) {
1638 >                    if (casTabAt(tab, i, null, r)) {
1639 >                        binCount = 1;
1640 >                        Node<K,V> node = null;
1641 >                        try {
1642 >                            if ((val = mappingFunction.apply(key)) != null)
1643 >                                node = new Node<K,V>(h, key, val, null);
1644 >                        } finally {
1645 >                            setTabAt(tab, i, node);
1646 >                        }
1647 >                    }
1648                  }
1649 <                r[i++] = (T)it.next();
1649 >                if (binCount != 0)
1650 >                    break;
1651              }
1652 <            if (a == r && i < n) {
1653 <                r[i] = null; // null-terminate
1654 <                return r;
1652 >            else if ((fh = f.hash) == MOVED)
1653 >                tab = helpTransfer(tab, f);
1654 >            else {
1655 >                boolean added = false;
1656 >                synchronized (f) {
1657 >                    if (tabAt(tab, i) == f) {
1658 >                        if (fh >= 0) {
1659 >                            binCount = 1;
1660 >                            for (Node<K,V> e = f;; ++binCount) {
1661 >                                K ek; V ev;
1662 >                                if (e.hash == h &&
1663 >                                    ((ek = e.key) == key ||
1664 >                                     (ek != null && key.equals(ek)))) {
1665 >                                    val = e.val;
1666 >                                    break;
1667 >                                }
1668 >                                Node<K,V> pred = e;
1669 >                                if ((e = e.next) == null) {
1670 >                                    if ((val = mappingFunction.apply(key)) != null) {
1671 >                                        added = true;
1672 >                                        pred.next = new Node<K,V>(h, key, val, null);
1673 >                                    }
1674 >                                    break;
1675 >                                }
1676 >                            }
1677 >                        }
1678 >                        else if (f instanceof TreeBin) {
1679 >                            binCount = 2;
1680 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1681 >                            TreeNode<K,V> r, p;
1682 >                            if ((r = t.root) != null &&
1683 >                                (p = r.findTreeNode(h, key, null)) != null)
1684 >                                val = p.val;
1685 >                            else if ((val = mappingFunction.apply(key)) != null) {
1686 >                                added = true;
1687 >                                t.putTreeVal(h, key, val);
1688 >                            }
1689 >                        }
1690 >                    }
1691 >                }
1692 >                if (binCount != 0) {
1693 >                    if (binCount >= TREEIFY_THRESHOLD)
1694 >                        treeifyBin(tab, i);
1695 >                    if (!added)
1696 >                        return val;
1697 >                    break;
1698 >                }
1699              }
3192            return (i == n) ? r : Arrays.copyOf(r, i);
3193        }
3194
3195        public final int hashCode() {
3196            int h = 0;
3197            for (Iterator<?> it = iterator(); it.hasNext();)
3198                h += it.next().hashCode();
3199            return h;
1700          }
1701 +        if (val != null)
1702 +            addCount(1L, binCount);
1703 +        return val;
1704 +    }
1705  
1706 <        public final String toString() {
1707 <            StringBuilder sb = new StringBuilder();
1708 <            sb.append('[');
1709 <            Iterator<?> it = iterator();
1710 <            if (it.hasNext()) {
1711 <                for (;;) {
1712 <                    Object e = it.next();
1713 <                    sb.append(e == this ? "(this Collection)" : e);
1714 <                    if (!it.hasNext())
1715 <                        break;
1716 <                    sb.append(',').append(' ');
1706 >    /**
1707 >     * If the value for the specified key is present, attempts to
1708 >     * compute a new mapping given the key and its current mapped
1709 >     * value.  The entire method invocation is performed atomically.
1710 >     * Some attempted update operations on this map by other threads
1711 >     * may be blocked while computation is in progress, so the
1712 >     * computation should be short and simple, and must not attempt to
1713 >     * update any other mappings of this map.
1714 >     *
1715 >     * @param key key with which a value may be associated
1716 >     * @param remappingFunction the function to compute a value
1717 >     * @return the new value associated with the specified key, or null if none
1718 >     * @throws NullPointerException if the specified key or remappingFunction
1719 >     *         is null
1720 >     * @throws IllegalStateException if the computation detectably
1721 >     *         attempts a recursive update to this map that would
1722 >     *         otherwise never complete
1723 >     * @throws RuntimeException or Error if the remappingFunction does so,
1724 >     *         in which case the mapping is unchanged
1725 >     */
1726 >    public V computeIfPresent(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
1727 >        if (key == null || remappingFunction == null)
1728 >            throw new NullPointerException();
1729 >        int h = spread(key.hashCode());
1730 >        V val = null;
1731 >        int delta = 0;
1732 >        int binCount = 0;
1733 >        for (Node<K,V>[] tab = table;;) {
1734 >            Node<K,V> f; int n, i, fh;
1735 >            if (tab == null || (n = tab.length) == 0)
1736 >                tab = initTable();
1737 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1738 >                break;
1739 >            else if ((fh = f.hash) == MOVED)
1740 >                tab = helpTransfer(tab, f);
1741 >            else {
1742 >                synchronized (f) {
1743 >                    if (tabAt(tab, i) == f) {
1744 >                        if (fh >= 0) {
1745 >                            binCount = 1;
1746 >                            for (Node<K,V> e = f, pred = null;; ++binCount) {
1747 >                                K ek;
1748 >                                if (e.hash == h &&
1749 >                                    ((ek = e.key) == key ||
1750 >                                     (ek != null && key.equals(ek)))) {
1751 >                                    val = remappingFunction.apply(key, e.val);
1752 >                                    if (val != null)
1753 >                                        e.val = val;
1754 >                                    else {
1755 >                                        delta = -1;
1756 >                                        Node<K,V> en = e.next;
1757 >                                        if (pred != null)
1758 >                                            pred.next = en;
1759 >                                        else
1760 >                                            setTabAt(tab, i, en);
1761 >                                    }
1762 >                                    break;
1763 >                                }
1764 >                                pred = e;
1765 >                                if ((e = e.next) == null)
1766 >                                    break;
1767 >                            }
1768 >                        }
1769 >                        else if (f instanceof TreeBin) {
1770 >                            binCount = 2;
1771 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1772 >                            TreeNode<K,V> r, p;
1773 >                            if ((r = t.root) != null &&
1774 >                                (p = r.findTreeNode(h, key, null)) != null) {
1775 >                                val = remappingFunction.apply(key, p.val);
1776 >                                if (val != null)
1777 >                                    p.val = val;
1778 >                                else {
1779 >                                    delta = -1;
1780 >                                    if (t.removeTreeNode(p))
1781 >                                        setTabAt(tab, i, untreeify(t.first));
1782 >                                }
1783 >                            }
1784 >                        }
1785 >                    }
1786                  }
1787 +                if (binCount != 0)
1788 +                    break;
1789              }
3215            return sb.append(']').toString();
1790          }
1791 +        if (delta != 0)
1792 +            addCount((long)delta, binCount);
1793 +        return val;
1794 +    }
1795  
1796 <        public final boolean containsAll(Collection<?> c) {
1797 <            if (c != this) {
1798 <                for (Iterator<?> it = c.iterator(); it.hasNext();) {
1799 <                    Object e = it.next();
1800 <                    if (e == null || !contains(e))
1801 <                        return false;
1796 >    /**
1797 >     * Attempts to compute a mapping for the specified key and its
1798 >     * current mapped value (or {@code null} if there is no current
1799 >     * mapping). The entire method invocation is performed atomically.
1800 >     * Some attempted update operations on this map by other threads
1801 >     * may be blocked while computation is in progress, so the
1802 >     * computation should be short and simple, and must not attempt to
1803 >     * update any other mappings of this Map.
1804 >     *
1805 >     * @param key key with which the specified value is to be associated
1806 >     * @param remappingFunction the function to compute a value
1807 >     * @return the new value associated with the specified key, or null if none
1808 >     * @throws NullPointerException if the specified key or remappingFunction
1809 >     *         is null
1810 >     * @throws IllegalStateException if the computation detectably
1811 >     *         attempts a recursive update to this map that would
1812 >     *         otherwise never complete
1813 >     * @throws RuntimeException or Error if the remappingFunction does so,
1814 >     *         in which case the mapping is unchanged
1815 >     */
1816 >    public V compute(K key,
1817 >                     BiFun<? super K, ? super V, ? extends V> remappingFunction) {
1818 >        if (key == null || remappingFunction == null)
1819 >            throw new NullPointerException();
1820 >        int h = spread(key.hashCode());
1821 >        V val = null;
1822 >        int delta = 0;
1823 >        int binCount = 0;
1824 >        for (Node<K,V>[] tab = table;;) {
1825 >            Node<K,V> f; int n, i, fh;
1826 >            if (tab == null || (n = tab.length) == 0)
1827 >                tab = initTable();
1828 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1829 >                Node<K,V> r = new ReservationNode<K,V>();
1830 >                synchronized (r) {
1831 >                    if (casTabAt(tab, i, null, r)) {
1832 >                        binCount = 1;
1833 >                        Node<K,V> node = null;
1834 >                        try {
1835 >                            if ((val = remappingFunction.apply(key, null)) != null) {
1836 >                                delta = 1;
1837 >                                node = new Node<K,V>(h, key, val, null);
1838 >                            }
1839 >                        } finally {
1840 >                            setTabAt(tab, i, node);
1841 >                        }
1842 >                    }
1843                  }
1844 +                if (binCount != 0)
1845 +                    break;
1846              }
1847 <            return true;
1848 <        }
1849 <
1850 <        public final boolean removeAll(Collection<?> c) {
1851 <            boolean modified = false;
1852 <            for (Iterator<?> it = iterator(); it.hasNext();) {
1853 <                if (c.contains(it.next())) {
1854 <                    it.remove();
1855 <                    modified = true;
1847 >            else if ((fh = f.hash) == MOVED)
1848 >                tab = helpTransfer(tab, f);
1849 >            else {
1850 >                synchronized (f) {
1851 >                    if (tabAt(tab, i) == f) {
1852 >                        if (fh >= 0) {
1853 >                            binCount = 1;
1854 >                            for (Node<K,V> e = f, pred = null;; ++binCount) {
1855 >                                K ek;
1856 >                                if (e.hash == h &&
1857 >                                    ((ek = e.key) == key ||
1858 >                                     (ek != null && key.equals(ek)))) {
1859 >                                    val = remappingFunction.apply(key, e.val);
1860 >                                    if (val != null)
1861 >                                        e.val = val;
1862 >                                    else {
1863 >                                        delta = -1;
1864 >                                        Node<K,V> en = e.next;
1865 >                                        if (pred != null)
1866 >                                            pred.next = en;
1867 >                                        else
1868 >                                            setTabAt(tab, i, en);
1869 >                                    }
1870 >                                    break;
1871 >                                }
1872 >                                pred = e;
1873 >                                if ((e = e.next) == null) {
1874 >                                    val = remappingFunction.apply(key, null);
1875 >                                    if (val != null) {
1876 >                                        delta = 1;
1877 >                                        pred.next =
1878 >                                            new Node<K,V>(h, key, val, null);
1879 >                                    }
1880 >                                    break;
1881 >                                }
1882 >                            }
1883 >                        }
1884 >                        else if (f instanceof TreeBin) {
1885 >                            binCount = 1;
1886 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1887 >                            TreeNode<K,V> r, p;
1888 >                            if ((r = t.root) != null)
1889 >                                p = r.findTreeNode(h, key, null);
1890 >                            else
1891 >                                p = null;
1892 >                            V pv = (p == null) ? null : p.val;
1893 >                            val = remappingFunction.apply(key, pv);
1894 >                            if (val != null) {
1895 >                                if (p != null)
1896 >                                    p.val = val;
1897 >                                else {
1898 >                                    delta = 1;
1899 >                                    t.putTreeVal(h, key, val);
1900 >                                }
1901 >                            }
1902 >                            else if (p != null) {
1903 >                                delta = -1;
1904 >                                if (t.removeTreeNode(p))
1905 >                                    setTabAt(tab, i, untreeify(t.first));
1906 >                            }
1907 >                        }
1908 >                    }
1909 >                }
1910 >                if (binCount != 0) {
1911 >                    if (binCount >= TREEIFY_THRESHOLD)
1912 >                        treeifyBin(tab, i);
1913 >                    break;
1914                  }
1915              }
3237            return modified;
1916          }
1917 +        if (delta != 0)
1918 +            addCount((long)delta, binCount);
1919 +        return val;
1920 +    }
1921  
1922 <        public final boolean retainAll(Collection<?> c) {
1923 <            boolean modified = false;
1924 <            for (Iterator<?> it = iterator(); it.hasNext();) {
1925 <                if (!c.contains(it.next())) {
1926 <                    it.remove();
1927 <                    modified = true;
1922 >    /**
1923 >     * If the specified key is not already associated with a
1924 >     * (non-null) value, associates it with the given value.
1925 >     * Otherwise, replaces the value with the results of the given
1926 >     * remapping function, or removes if {@code null}. The entire
1927 >     * method invocation is performed atomically.  Some attempted
1928 >     * update operations on this map by other threads may be blocked
1929 >     * while computation is in progress, so the computation should be
1930 >     * short and simple, and must not attempt to update any other
1931 >     * mappings of this Map.
1932 >     *
1933 >     * @param key key with which the specified value is to be associated
1934 >     * @param value the value to use if absent
1935 >     * @param remappingFunction the function to recompute a value if present
1936 >     * @return the new value associated with the specified key, or null if none
1937 >     * @throws NullPointerException if the specified key or the
1938 >     *         remappingFunction is null
1939 >     * @throws RuntimeException or Error if the remappingFunction does so,
1940 >     *         in which case the mapping is unchanged
1941 >     */
1942 >    public V merge(K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
1943 >        if (key == null || value == null || remappingFunction == null)
1944 >            throw new NullPointerException();
1945 >        int h = spread(key.hashCode());
1946 >        V val = null;
1947 >        int delta = 0;
1948 >        int binCount = 0;
1949 >        for (Node<K,V>[] tab = table;;) {
1950 >            Node<K,V> f; int n, i, fh;
1951 >            if (tab == null || (n = tab.length) == 0)
1952 >                tab = initTable();
1953 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1954 >                if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1955 >                    delta = 1;
1956 >                    val = value;
1957 >                    break;
1958 >                }
1959 >            }
1960 >            else if ((fh = f.hash) == MOVED)
1961 >                tab = helpTransfer(tab, f);
1962 >            else {
1963 >                synchronized (f) {
1964 >                    if (tabAt(tab, i) == f) {
1965 >                        if (fh >= 0) {
1966 >                            binCount = 1;
1967 >                            for (Node<K,V> e = f, pred = null;; ++binCount) {
1968 >                                K ek;
1969 >                                if (e.hash == h &&
1970 >                                    ((ek = e.key) == key ||
1971 >                                     (ek != null && key.equals(ek)))) {
1972 >                                    val = remappingFunction.apply(e.val, value);
1973 >                                    if (val != null)
1974 >                                        e.val = val;
1975 >                                    else {
1976 >                                        delta = -1;
1977 >                                        Node<K,V> en = e.next;
1978 >                                        if (pred != null)
1979 >                                            pred.next = en;
1980 >                                        else
1981 >                                            setTabAt(tab, i, en);
1982 >                                    }
1983 >                                    break;
1984 >                                }
1985 >                                pred = e;
1986 >                                if ((e = e.next) == null) {
1987 >                                    delta = 1;
1988 >                                    val = value;
1989 >                                    pred.next =
1990 >                                        new Node<K,V>(h, key, val, null);
1991 >                                    break;
1992 >                                }
1993 >                            }
1994 >                        }
1995 >                        else if (f instanceof TreeBin) {
1996 >                            binCount = 2;
1997 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1998 >                            TreeNode<K,V> r = t.root;
1999 >                            TreeNode<K,V> p = (r == null) ? null :
2000 >                                r.findTreeNode(h, key, null);
2001 >                            val = (p == null) ? value :
2002 >                                remappingFunction.apply(p.val, value);
2003 >                            if (val != null) {
2004 >                                if (p != null)
2005 >                                    p.val = val;
2006 >                                else {
2007 >                                    delta = 1;
2008 >                                    t.putTreeVal(h, key, val);
2009 >                                }
2010 >                            }
2011 >                            else if (p != null) {
2012 >                                delta = -1;
2013 >                                if (t.removeTreeNode(p))
2014 >                                    setTabAt(tab, i, untreeify(t.first));
2015 >                            }
2016 >                        }
2017 >                    }
2018 >                }
2019 >                if (binCount != 0) {
2020 >                    if (binCount >= TREEIFY_THRESHOLD)
2021 >                        treeifyBin(tab, i);
2022 >                    break;
2023                  }
2024              }
3248            return modified;
2025          }
2026 +        if (delta != 0)
2027 +            addCount((long)delta, binCount);
2028 +        return val;
2029 +    }
2030  
2031 +    // Hashtable legacy methods
2032 +
2033 +    /**
2034 +     * Legacy method testing if some key maps into the specified value
2035 +     * in this table.  This method is identical in functionality to
2036 +     * {@link #containsValue(Object)}, and exists solely to ensure
2037 +     * full compatibility with class {@link java.util.Hashtable},
2038 +     * which supported this method prior to introduction of the
2039 +     * Java Collections framework.
2040 +     *
2041 +     * @param  value a value to search for
2042 +     * @return {@code true} if and only if some key maps to the
2043 +     *         {@code value} argument in this table as
2044 +     *         determined by the {@code equals} method;
2045 +     *         {@code false} otherwise
2046 +     * @throws NullPointerException if the specified value is null
2047 +     */
2048 +    @Deprecated public boolean contains(Object value) {
2049 +        return containsValue(value);
2050      }
2051  
2052 <    static final class KeySet<K,V> extends CHMView<K,V> implements Set<K> {
2053 <        KeySet(ConcurrentHashMapV8<K, V> map)  {
2054 <            super(map);
2055 <        }
2056 <        public final boolean contains(Object o) { return map.containsKey(o); }
2057 <        public final boolean remove(Object o)   { return map.remove(o) != null; }
2058 <        public final Iterator<K> iterator() {
2059 <            return new KeyIterator<K,V>(map);
2060 <        }
2061 <        public final boolean add(K e) {
3263 <            throw new UnsupportedOperationException();
3264 <        }
3265 <        public final boolean addAll(Collection<? extends K> c) {
3266 <            throw new UnsupportedOperationException();
3267 <        }
3268 <        public boolean equals(Object o) {
3269 <            Set<?> c;
3270 <            return ((o instanceof Set) &&
3271 <                    ((c = (Set<?>)o) == this ||
3272 <                     (containsAll(c) && c.containsAll(this))));
3273 <        }
2052 >    /**
2053 >     * Returns an enumeration of the keys in this table.
2054 >     *
2055 >     * @return an enumeration of the keys in this table
2056 >     * @see #keySet()
2057 >     */
2058 >    public Enumeration<K> keys() {
2059 >        Node<K,V>[] t;
2060 >        int f = (t = table) == null ? 0 : t.length;
2061 >        return new KeyIterator<K,V>(t, f, 0, f, this);
2062      }
2063  
2064 +    /**
2065 +     * Returns an enumeration of the values in this table.
2066 +     *
2067 +     * @return an enumeration of the values in this table
2068 +     * @see #values()
2069 +     */
2070 +    public Enumeration<V> elements() {
2071 +        Node<K,V>[] t;
2072 +        int f = (t = table) == null ? 0 : t.length;
2073 +        return new ValueIterator<K,V>(t, f, 0, f, this);
2074 +    }
2075  
2076 <    static final class Values<K,V> extends CHMView<K,V>
2077 <        implements Collection<V> {
2078 <        Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
2079 <        public final boolean contains(Object o) { return map.containsValue(o); }
2080 <        public final boolean remove(Object o) {
2081 <            if (o != null) {
2082 <                Iterator<V> it = new ValueIterator<K,V>(map);
2083 <                while (it.hasNext()) {
2084 <                    if (o.equals(it.next())) {
2085 <                        it.remove();
2086 <                        return true;
2076 >    // ConcurrentHashMapV8-only methods
2077 >
2078 >    /**
2079 >     * Returns the number of mappings. This method should be used
2080 >     * instead of {@link #size} because a ConcurrentHashMapV8 may
2081 >     * contain more mappings than can be represented as an int. The
2082 >     * value returned is an estimate; the actual count may differ if
2083 >     * there are concurrent insertions or removals.
2084 >     *
2085 >     * @return the number of mappings
2086 >     * @since 1.8
2087 >     */
2088 >    public long mappingCount() {
2089 >        long n = sumCount();
2090 >        return (n < 0L) ? 0L : n; // ignore transient negative values
2091 >    }
2092 >
2093 >    /**
2094 >     * Creates a new {@link Set} backed by a ConcurrentHashMapV8
2095 >     * from the given type to {@code Boolean.TRUE}.
2096 >     *
2097 >     * @return the new set
2098 >     * @since 1.8
2099 >     */
2100 >    public static <K> KeySetView<K,Boolean> newKeySet() {
2101 >        return new KeySetView<K,Boolean>
2102 >            (new ConcurrentHashMapV8<K,Boolean>(), Boolean.TRUE);
2103 >    }
2104 >
2105 >    /**
2106 >     * Creates a new {@link Set} backed by a ConcurrentHashMapV8
2107 >     * from the given type to {@code Boolean.TRUE}.
2108 >     *
2109 >     * @param initialCapacity The implementation performs internal
2110 >     * sizing to accommodate this many elements.
2111 >     * @return the new set
2112 >     * @throws IllegalArgumentException if the initial capacity of
2113 >     * elements is negative
2114 >     * @since 1.8
2115 >     */
2116 >    public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2117 >        return new KeySetView<K,Boolean>
2118 >            (new ConcurrentHashMapV8<K,Boolean>(initialCapacity), Boolean.TRUE);
2119 >    }
2120 >
2121 >    /**
2122 >     * Returns a {@link Set} view of the keys in this map, using the
2123 >     * given common mapped value for any additions (i.e., {@link
2124 >     * Collection#add} and {@link Collection#addAll(Collection)}).
2125 >     * This is of course only appropriate if it is acceptable to use
2126 >     * the same value for all additions from this view.
2127 >     *
2128 >     * @param mappedValue the mapped value to use for any additions
2129 >     * @return the set view
2130 >     * @throws NullPointerException if the mappedValue is null
2131 >     */
2132 >    public KeySetView<K,V> keySet(V mappedValue) {
2133 >        if (mappedValue == null)
2134 >            throw new NullPointerException();
2135 >        return new KeySetView<K,V>(this, mappedValue);
2136 >    }
2137 >
2138 >    /* ---------------- Special Nodes -------------- */
2139 >
2140 >    /**
2141 >     * A node inserted at head of bins during transfer operations.
2142 >     */
2143 >    static final class ForwardingNode<K,V> extends Node<K,V> {
2144 >        final Node<K,V>[] nextTable;
2145 >        ForwardingNode(Node<K,V>[] tab) {
2146 >            super(MOVED, null, null, null);
2147 >            this.nextTable = tab;
2148 >        }
2149 >
2150 >        Node<K,V> find(int h, Object k) {
2151 >            // loop to avoid arbitrarily deep recursion on forwarding nodes
2152 >            outer: for (Node<K,V>[] tab = nextTable;;) {
2153 >                Node<K,V> e; int n;
2154 >                if (k == null || tab == null || (n = tab.length) == 0 ||
2155 >                    (e = tabAt(tab, (n - 1) & h)) == null)
2156 >                    return null;
2157 >                for (;;) {
2158 >                    int eh; K ek;
2159 >                    if ((eh = e.hash) == h &&
2160 >                        ((ek = e.key) == k || (ek != null && k.equals(ek))))
2161 >                        return e;
2162 >                    if (eh < 0) {
2163 >                        if (e instanceof ForwardingNode) {
2164 >                            tab = ((ForwardingNode<K,V>)e).nextTable;
2165 >                            continue outer;
2166 >                        }
2167 >                        else
2168 >                            return e.find(h, k);
2169                      }
2170 +                    if ((e = e.next) == null)
2171 +                        return null;
2172                  }
2173              }
3291            return false;
3292        }
3293        public final Iterator<V> iterator() {
3294            return new ValueIterator<K,V>(map);
3295        }
3296        public final boolean add(V e) {
3297            throw new UnsupportedOperationException();
2174          }
3299        public final boolean addAll(Collection<? extends V> c) {
3300            throw new UnsupportedOperationException();
3301        }
3302
2175      }
2176  
2177 <    static final class EntrySet<K,V> extends CHMView<K,V>
2178 <        implements Set<Map.Entry<K,V>> {
2179 <        EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
2180 <        public final boolean contains(Object o) {
2181 <            Object k, v, r; Map.Entry<?,?> e;
2182 <            return ((o instanceof Map.Entry) &&
3311 <                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3312 <                    (r = map.get(k)) != null &&
3313 <                    (v = e.getValue()) != null &&
3314 <                    (v == r || v.equals(r)));
3315 <        }
3316 <        public final boolean remove(Object o) {
3317 <            Object k, v; Map.Entry<?,?> e;
3318 <            return ((o instanceof Map.Entry) &&
3319 <                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3320 <                    (v = e.getValue()) != null &&
3321 <                    map.remove(k, v));
3322 <        }
3323 <        public final Iterator<Map.Entry<K,V>> iterator() {
3324 <            return new EntryIterator<K,V>(map);
3325 <        }
3326 <        public final boolean add(Entry<K,V> e) {
3327 <            throw new UnsupportedOperationException();
3328 <        }
3329 <        public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3330 <            throw new UnsupportedOperationException();
2177 >    /**
2178 >     * A place-holder node used in computeIfAbsent and compute
2179 >     */
2180 >    static final class ReservationNode<K,V> extends Node<K,V> {
2181 >        ReservationNode() {
2182 >            super(RESERVED, null, null, null);
2183          }
2184 <        public boolean equals(Object o) {
2185 <            Set<?> c;
2186 <            return ((o instanceof Set) &&
3335 <                    ((c = (Set<?>)o) == this ||
3336 <                     (containsAll(c) && c.containsAll(this))));
2184 >
2185 >        Node<K,V> find(int h, Object k) {
2186 >            return null;
2187          }
2188      }
2189  
2190 <    /* ---------------- Serialization Support -------------- */
2190 >    /* ---------------- Table Initialization and Resizing -------------- */
2191  
2192      /**
2193 <     * Stripped-down version of helper class used in previous version,
3344 <     * declared for the sake of serialization compatibility
2193 >     * Initializes table, using the size recorded in sizeCtl.
2194       */
2195 <    static class Segment<K,V> implements Serializable {
2196 <        private static final long serialVersionUID = 2249069246763182397L;
2197 <        final float loadFactor;
2198 <        Segment(float lf) { this.loadFactor = lf; }
2195 >    private final Node<K,V>[] initTable() {
2196 >        Node<K,V>[] tab; int sc;
2197 >        while ((tab = table) == null || tab.length == 0) {
2198 >            if ((sc = sizeCtl) < 0)
2199 >                Thread.yield(); // lost initialization race; just spin
2200 >            else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2201 >                try {
2202 >                    if ((tab = table) == null || tab.length == 0) {
2203 >                        int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2204 >                        @SuppressWarnings({"rawtypes","unchecked"})
2205 >                            Node<K,V>[] nt = (Node<K,V>[])new Node[n];
2206 >                        table = tab = nt;
2207 >                        sc = n - (n >>> 2);
2208 >                    }
2209 >                } finally {
2210 >                    sizeCtl = sc;
2211 >                }
2212 >                break;
2213 >            }
2214 >        }
2215 >        return tab;
2216      }
2217  
2218      /**
2219 <     * Saves the state of the {@code ConcurrentHashMapV8} instance to a
2220 <     * stream (i.e., serializes it).
2221 <     * @param s the stream
2222 <     * @serialData
2223 <     * the key (Object) and value (Object)
2224 <     * for each key-value mapping, followed by a null pair.
2225 <     * The key-value mappings are emitted in no particular order.
2226 <     */
2227 <    @SuppressWarnings("unchecked") private void writeObject(java.io.ObjectOutputStream s)
2228 <        throws java.io.IOException {
2229 <        if (segments == null) { // for serialization compatibility
2230 <            segments = (Segment<K,V>[])
2231 <                new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
2232 <            for (int i = 0; i < segments.length; ++i)
2233 <                segments[i] = new Segment<K,V>(LOAD_FACTOR);
2234 <        }
2235 <        s.defaultWriteObject();
2236 <        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2237 <        Object v;
2238 <        while ((v = it.advance()) != null) {
2239 <            s.writeObject(it.nextKey);
2240 <            s.writeObject(v);
2219 >     * Adds to count, and if table is too small and not already
2220 >     * resizing, initiates transfer. If already resizing, helps
2221 >     * perform transfer if work is available.  Rechecks occupancy
2222 >     * after a transfer to see if another resize is already needed
2223 >     * because resizings are lagging additions.
2224 >     *
2225 >     * @param x the count to add
2226 >     * @param check if <0, don't check resize, if <= 1 only check if uncontended
2227 >     */
2228 >    private final void addCount(long x, int check) {
2229 >        CounterCell[] as; long b, s;
2230 >        if ((as = counterCells) != null ||
2231 >            !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2232 >            CounterHashCode hc; CounterCell a; long v; int m;
2233 >            boolean uncontended = true;
2234 >            if ((hc = threadCounterHashCode.get()) == null ||
2235 >                as == null || (m = as.length - 1) < 0 ||
2236 >                (a = as[m & hc.code]) == null ||
2237 >                !(uncontended =
2238 >                  U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2239 >                fullAddCount(x, hc, uncontended);
2240 >                return;
2241 >            }
2242 >            if (check <= 1)
2243 >                return;
2244 >            s = sumCount();
2245 >        }
2246 >        if (check >= 0) {
2247 >            Node<K,V>[] tab, nt; int sc;
2248 >            while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2249 >                   tab.length < MAXIMUM_CAPACITY) {
2250 >                if (sc < 0) {
2251 >                    if (sc == -1 || transferIndex <= transferOrigin ||
2252 >                        (nt = nextTable) == null)
2253 >                        break;
2254 >                    if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
2255 >                        transfer(tab, nt);
2256 >                }
2257 >                else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
2258 >                    transfer(tab, null);
2259 >                s = sumCount();
2260 >            }
2261          }
3376        s.writeObject(null);
3377        s.writeObject(null);
3378        segments = null; // throw away
2262      }
2263  
2264      /**
2265 <     * Reconstitutes the instance from a stream (that is, deserializes it).
3383 <     * @param s the stream
2265 >     * Helps transfer if a resize is in progress.
2266       */
2267 <    @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s)
2268 <        throws java.io.IOException, ClassNotFoundException {
2269 <        s.defaultReadObject();
2270 <        this.segments = null; // unneeded
2271 <        // initialize transient final field
2272 <        UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
2267 >    final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2268 >        Node<K,V>[] nextTab; int sc;
2269 >        if ((f instanceof ForwardingNode) &&
2270 >            (nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2271 >            if (nextTab == nextTable && tab == table &&
2272 >                transferIndex > transferOrigin && (sc = sizeCtl) < -1 &&
2273 >                U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
2274 >                transfer(tab, nextTab);
2275 >            return nextTab;
2276 >        }
2277 >        return table;
2278 >    }
2279  
2280 <        // Create all nodes, then place in table once size is known
2281 <        long size = 0L;
2282 <        Node p = null;
2283 <        for (;;) {
2284 <            K k = (K) s.readObject();
2285 <            V v = (V) s.readObject();
2286 <            if (k != null && v != null) {
2287 <                int h = spread(k.hashCode());
2288 <                p = new Node(h, k, v, p);
2289 <                ++size;
2280 >    /**
2281 >     * Tries to presize table to accommodate the given number of elements.
2282 >     *
2283 >     * @param size number of elements (doesn't need to be perfectly accurate)
2284 >     */
2285 >    private final void tryPresize(int size) {
2286 >        int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2287 >            tableSizeFor(size + (size >>> 1) + 1);
2288 >        int sc;
2289 >        while ((sc = sizeCtl) >= 0) {
2290 >            Node<K,V>[] tab = table; int n;
2291 >            if (tab == null || (n = tab.length) == 0) {
2292 >                n = (sc > c) ? sc : c;
2293 >                if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2294 >                    try {
2295 >                        if (table == tab) {
2296 >                            @SuppressWarnings({"rawtypes","unchecked"})
2297 >                                Node<K,V>[] nt = (Node<K,V>[])new Node[n];
2298 >                            table = nt;
2299 >                            sc = n - (n >>> 2);
2300 >                        }
2301 >                    } finally {
2302 >                        sizeCtl = sc;
2303 >                    }
2304 >                }
2305              }
2306 <            else
2306 >            else if (c <= sc || n >= MAXIMUM_CAPACITY)
2307                  break;
2308 +            else if (tab == table &&
2309 +                     U.compareAndSwapInt(this, SIZECTL, sc, -2))
2310 +                transfer(tab, null);
2311          }
2312 <        if (p != null) {
2313 <            boolean init = false;
2314 <            int n;
2315 <            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
2316 <                n = MAXIMUM_CAPACITY;
2317 <            else {
2318 <                int sz = (int)size;
2319 <                n = tableSizeFor(sz + (sz >>> 1) + 1);
2320 <            }
2321 <            int sc = sizeCtl;
2322 <            boolean collide = false;
2323 <            if (n > sc &&
2324 <                UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
2325 <                try {
2326 <                    if (table == null) {
2327 <                        init = true;
2328 <                        Node[] tab = new Node[n];
2329 <                        int mask = n - 1;
2330 <                        while (p != null) {
2331 <                            int j = p.hash & mask;
2332 <                            Node next = p.next;
2333 <                            Node q = p.next = tabAt(tab, j);
2334 <                            setTabAt(tab, j, p);
2335 <                            if (!collide && q != null && q.hash == p.hash)
2336 <                                collide = true;
2337 <                            p = next;
2338 <                        }
2339 <                        table = tab;
2340 <                        counter.add(size);
2341 <                        sc = n - (n >>> 2);
2312 >    }
2313 >
2314 >    /**
2315 >     * Moves and/or copies the nodes in each bin to new table. See
2316 >     * above for explanation.
2317 >     */
2318 >    private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2319 >        int n = tab.length, stride;
2320 >        if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2321 >            stride = MIN_TRANSFER_STRIDE; // subdivide range
2322 >        if (nextTab == null) {            // initiating
2323 >            try {
2324 >                @SuppressWarnings({"rawtypes","unchecked"})
2325 >                    Node<K,V>[] nt = (Node<K,V>[])new Node[n << 1];
2326 >                nextTab = nt;
2327 >            } catch (Throwable ex) {      // try to cope with OOME
2328 >                sizeCtl = Integer.MAX_VALUE;
2329 >                return;
2330 >            }
2331 >            nextTable = nextTab;
2332 >            transferOrigin = n;
2333 >            transferIndex = n;
2334 >            ForwardingNode<K,V> rev = new ForwardingNode<K,V>(tab);
2335 >            for (int k = n; k > 0;) {    // progressively reveal ready slots
2336 >                int nextk = (k > stride) ? k - stride : 0;
2337 >                for (int m = nextk; m < k; ++m)
2338 >                    nextTab[m] = rev;
2339 >                for (int m = n + nextk; m < n + k; ++m)
2340 >                    nextTab[m] = rev;
2341 >                U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
2342 >            }
2343 >        }
2344 >        int nextn = nextTab.length;
2345 >        ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2346 >        boolean advance = true;
2347 >        boolean finishing = false; // to ensure sweep before committing nextTab
2348 >        for (int i = 0, bound = 0;;) {
2349 >            int nextIndex, nextBound, fh; Node<K,V> f;
2350 >            while (advance) {
2351 >                if (--i >= bound || finishing)
2352 >                    advance = false;
2353 >                else if ((nextIndex = transferIndex) <= transferOrigin) {
2354 >                    i = -1;
2355 >                    advance = false;
2356 >                }
2357 >                else if (U.compareAndSwapInt
2358 >                         (this, TRANSFERINDEX, nextIndex,
2359 >                          nextBound = (nextIndex > stride ?
2360 >                                       nextIndex - stride : 0))) {
2361 >                    bound = nextBound;
2362 >                    i = nextIndex - 1;
2363 >                    advance = false;
2364 >                }
2365 >            }
2366 >            if (i < 0 || i >= n || i + n >= nextn) {
2367 >                if (finishing) {
2368 >                    nextTable = null;
2369 >                    table = nextTab;
2370 >                    sizeCtl = (n << 1) - (n >>> 1);
2371 >                    return;
2372 >                }
2373 >                for (int sc;;) {
2374 >                    if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
2375 >                        if (sc != -1)
2376 >                            return;
2377 >                        finishing = advance = true;
2378 >                        i = n; // recheck before commit
2379 >                        break;
2380                      }
3437                } finally {
3438                    sizeCtl = sc;
2381                  }
2382 <                if (collide) { // rescan and convert to TreeBins
2383 <                    Node[] tab = table;
2384 <                    for (int i = 0; i < tab.length; ++i) {
2385 <                        int c = 0;
2386 <                        for (Node e = tabAt(tab, i); e != null; e = e.next) {
2387 <                            if (++c > TREE_THRESHOLD &&
2388 <                                (e.key instanceof Comparable)) {
2389 <                                replaceWithTreeBin(tab, i, e.key);
2390 <                                break;
2382 >            }
2383 >            else if ((f = tabAt(tab, i)) == null) {
2384 >                if (casTabAt(tab, i, null, fwd)) {
2385 >                    setTabAt(nextTab, i, null);
2386 >                    setTabAt(nextTab, i + n, null);
2387 >                    advance = true;
2388 >                }
2389 >            }
2390 >            else if ((fh = f.hash) == MOVED)
2391 >                advance = true; // already processed
2392 >            else {
2393 >                synchronized (f) {
2394 >                    if (tabAt(tab, i) == f) {
2395 >                        Node<K,V> ln, hn;
2396 >                        if (fh >= 0) {
2397 >                            int runBit = fh & n;
2398 >                            Node<K,V> lastRun = f;
2399 >                            for (Node<K,V> p = f.next; p != null; p = p.next) {
2400 >                                int b = p.hash & n;
2401 >                                if (b != runBit) {
2402 >                                    runBit = b;
2403 >                                    lastRun = p;
2404 >                                }
2405 >                            }
2406 >                            if (runBit == 0) {
2407 >                                ln = lastRun;
2408 >                                hn = null;
2409                              }
2410 +                            else {
2411 +                                hn = lastRun;
2412 +                                ln = null;
2413 +                            }
2414 +                            for (Node<K,V> p = f; p != lastRun; p = p.next) {
2415 +                                int ph = p.hash; K pk = p.key; V pv = p.val;
2416 +                                if ((ph & n) == 0)
2417 +                                    ln = new Node<K,V>(ph, pk, pv, ln);
2418 +                                else
2419 +                                    hn = new Node<K,V>(ph, pk, pv, hn);
2420 +                            }
2421 +                            setTabAt(nextTab, i, ln);
2422 +                            setTabAt(nextTab, i + n, hn);
2423 +                            setTabAt(tab, i, fwd);
2424 +                            advance = true;
2425 +                        }
2426 +                        else if (f instanceof TreeBin) {
2427 +                            TreeBin<K,V> t = (TreeBin<K,V>)f;
2428 +                            TreeNode<K,V> lo = null, loTail = null;
2429 +                            TreeNode<K,V> hi = null, hiTail = null;
2430 +                            int lc = 0, hc = 0;
2431 +                            for (Node<K,V> e = t.first; e != null; e = e.next) {
2432 +                                int h = e.hash;
2433 +                                TreeNode<K,V> p = new TreeNode<K,V>
2434 +                                    (h, e.key, e.val, null, null);
2435 +                                if ((h & n) == 0) {
2436 +                                    if ((p.prev = loTail) == null)
2437 +                                        lo = p;
2438 +                                    else
2439 +                                        loTail.next = p;
2440 +                                    loTail = p;
2441 +                                    ++lc;
2442 +                                }
2443 +                                else {
2444 +                                    if ((p.prev = hiTail) == null)
2445 +                                        hi = p;
2446 +                                    else
2447 +                                        hiTail.next = p;
2448 +                                    hiTail = p;
2449 +                                    ++hc;
2450 +                                }
2451 +                            }
2452 +                            ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2453 +                                (hc != 0) ? new TreeBin<K,V>(lo) : t;
2454 +                            hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2455 +                                (lc != 0) ? new TreeBin<K,V>(hi) : t;
2456 +                            setTabAt(nextTab, i, ln);
2457 +                            setTabAt(nextTab, i + n, hn);
2458 +                            setTabAt(tab, i, fwd);
2459 +                            advance = true;
2460                          }
2461                      }
2462                  }
2463              }
3454            if (!init) { // Can only happen if unsafely published.
3455                while (p != null) {
3456                    internalPut(p.key, p.val);
3457                    p = p.next;
3458                }
3459            }
2464          }
2465      }
2466  
2467 +    /* ---------------- Conversion from/to TreeBins -------------- */
2468  
2469 <    // -------------------------------------------------------
2470 <
2471 <    // Sams
2472 <    /** Interface describing a void action of one argument */
2473 <    public interface Action<A> { void apply(A a); }
2474 <    /** Interface describing a void action of two arguments */
2475 <    public interface BiAction<A,B> { void apply(A a, B b); }
2476 <    /** Interface describing a function of one argument */
2477 <    public interface Fun<A,T> { T apply(A a); }
2478 <    /** Interface describing a function of two arguments */
2479 <    public interface BiFun<A,B,T> { T apply(A a, B b); }
2480 <    /** Interface describing a function of no arguments */
2481 <    public interface Generator<T> { T apply(); }
2482 <    /** Interface describing a function mapping its argument to a double */
2483 <    public interface ObjectToDouble<A> { double apply(A a); }
2484 <    /** Interface describing a function mapping its argument to a long */
2485 <    public interface ObjectToLong<A> { long apply(A a); }
2486 <    /** Interface describing a function mapping its argument to an int */
2487 <    public interface ObjectToInt<A> {int apply(A a); }
2488 <    /** Interface describing a function mapping two arguments to a double */
2489 <    public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
2490 <    /** Interface describing a function mapping two arguments to a long */
2491 <    public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
2492 <    /** Interface describing a function mapping two arguments to an int */
2493 <    public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }
2494 <    /** Interface describing a function mapping a double to a double */
2495 <    public interface DoubleToDouble { double apply(double a); }
2496 <    /** Interface describing a function mapping a long to a long */
2497 <    public interface LongToLong { long apply(long a); }
2498 <    /** Interface describing a function mapping an int to an int */
2499 <    public interface IntToInt { int apply(int a); }
2500 <    /** Interface describing a function mapping two doubles to a double */
3496 <    public interface DoubleByDoubleToDouble { double apply(double a, double b); }
3497 <    /** Interface describing a function mapping two longs to a long */
3498 <    public interface LongByLongToLong { long apply(long a, long b); }
3499 <    /** Interface describing a function mapping two ints to an int */
3500 <    public interface IntByIntToInt { int apply(int a, int b); }
3501 <
3502 <
3503 <    // -------------------------------------------------------
2469 >    /**
2470 >     * Replaces all linked nodes in bin at given index unless table is
2471 >     * too small, in which case resizes instead.
2472 >     */
2473 >    private final void treeifyBin(Node<K,V>[] tab, int index) {
2474 >        Node<K,V> b; int n, sc;
2475 >        if (tab != null) {
2476 >            if ((n = tab.length) < MIN_TREEIFY_CAPACITY) {
2477 >                if (tab == table && (sc = sizeCtl) >= 0 &&
2478 >                    U.compareAndSwapInt(this, SIZECTL, sc, -2))
2479 >                    transfer(tab, null);
2480 >            }
2481 >            else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2482 >                synchronized (b) {
2483 >                    if (tabAt(tab, index) == b) {
2484 >                        TreeNode<K,V> hd = null, tl = null;
2485 >                        for (Node<K,V> e = b; e != null; e = e.next) {
2486 >                            TreeNode<K,V> p =
2487 >                                new TreeNode<K,V>(e.hash, e.key, e.val,
2488 >                                                  null, null);
2489 >                            if ((p.prev = tl) == null)
2490 >                                hd = p;
2491 >                            else
2492 >                                tl.next = p;
2493 >                            tl = p;
2494 >                        }
2495 >                        setTabAt(tab, index, new TreeBin<K,V>(hd));
2496 >                    }
2497 >                }
2498 >            }
2499 >        }
2500 >    }
2501  
2502      /**
2503 <     * Returns an extended {@link Parallel} view of this map using the
3507 <     * given executor for bulk parallel operations.
3508 <     *
3509 <     * @param executor the executor
3510 <     * @return a parallel view
2503 >     * Returns a list on non-TreeNodes replacing those in given list.
2504       */
2505 <    public Parallel parallel(ForkJoinPool executor)  {
2506 <        return new Parallel(executor);
2505 >    static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2506 >        Node<K,V> hd = null, tl = null;
2507 >        for (Node<K,V> q = b; q != null; q = q.next) {
2508 >            Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2509 >            if (tl == null)
2510 >                hd = p;
2511 >            else
2512 >                tl.next = p;
2513 >            tl = p;
2514 >        }
2515 >        return hd;
2516      }
2517  
2518 +    /* ---------------- TreeNodes -------------- */
2519 +
2520      /**
2521 <     * An extended view of a ConcurrentHashMap supporting bulk
3518 <     * parallel operations. These operations are designed to be
3519 <     * safely, and often sensibly, applied even with maps that are
3520 <     * being concurrently updated by other threads; for example, when
3521 <     * computing a snapshot summary of the values in a shared
3522 <     * registry.  There are three kinds of operation, each with four
3523 <     * forms, accepting functions with Keys, Values, Entries, and
3524 <     * (Key, Value) arguments and/or return values. Because the
3525 <     * elements of a ConcurrentHashMap are not ordered in any
3526 <     * particular way, and may be processed in different orders in
3527 <     * different parallel executions, the correctness of supplied
3528 <     * functions should not depend on any ordering, or on any other
3529 <     * objects or values that may transiently change while computation
3530 <     * is in progress; and except for forEach actions, should ideally
3531 <     * be side-effect-free.
3532 <     *
3533 <     * <ul>
3534 <     * <li> forEach: Perform a given action on each element.
3535 <     * A variant form applies a given transformation on each element
3536 <     * before performing the action.</li>
3537 <     *
3538 <     * <li> search: Return the first available non-null result of
3539 <     * applying a given function on each element; skipping further
3540 <     * search when a result is found.</li>
3541 <     *
3542 <     * <li> reduce: Accumulate each element.  The supplied reduction
3543 <     * function cannot rely on ordering (more formally, it should be
3544 <     * both associative and commutative).  There are five variants:
3545 <     *
3546 <     * <ul>
3547 <     *
3548 <     * <li> Plain reductions. (There is not a form of this method for
3549 <     * (key, value) function arguments since there is no corresponding
3550 <     * return type.)</li>
3551 <     *
3552 <     * <li> Mapped reductions that accumulate the results of a given
3553 <     * function applied to each element.</li>
3554 <     *
3555 <     * <li> Reductions to scalar doubles, longs, and ints, using a
3556 <     * given basis value.</li>
3557 <     *
3558 <     * </li>
3559 <     * </ul>
3560 <     * </ul>
3561 <     *
3562 <     * <p>The concurrency properties of the bulk operations follow
3563 <     * from those of ConcurrentHashMap: Any non-null result returned
3564 <     * from {@code get(key)} and related access methods bears a
3565 <     * happens-before relation with the associated insertion or
3566 <     * update.  The result of any bulk operation reflects the
3567 <     * composition of these per-element relations (but is not
3568 <     * necessarily atomic with respect to the map as a whole unless it
3569 <     * is somehow known to be quiescent).  Conversely, because keys
3570 <     * and values in the map are never null, null serves as a reliable
3571 <     * atomic indicator of the current lack of any result.  To
3572 <     * maintain this property, null serves as an implicit basis for
3573 <     * all non-scalar reduction operations. For the double, long, and
3574 <     * int versions, the basis should be one that, when combined with
3575 <     * any other value, returns that other value (more formally, it
3576 <     * should be the identity element for the reduction). Most common
3577 <     * reductions have these properties; for example, computing a sum
3578 <     * with basis 0 or a minimum with basis MAX_VALUE.
3579 <     *
3580 <     * <p>Search and transformation functions provided as arguments
3581 <     * should similarly return null to indicate the lack of any result
3582 <     * (in which case it is not used). In the case of mapped
3583 <     * reductions, this also enables transformations to serve as
3584 <     * filters, returning null (or, in the case of primitive
3585 <     * specializations, the identity basis) if the element should not
3586 <     * be combined. You can create compound transformations and
3587 <     * filterings by composing them yourself under this "null means
3588 <     * there is nothing there now" rule before using them in search or
3589 <     * reduce operations.
3590 <     *
3591 <     * <p>Methods accepting and/or returning Entry arguments maintain
3592 <     * key-value associations. They may be useful for example when
3593 <     * finding the key for the greatest value. Note that "plain" Entry
3594 <     * arguments can be supplied using {@code new
3595 <     * AbstractMap.SimpleEntry(k,v)}.
3596 <     *
3597 <     * <p> Bulk operations may complete abruptly, throwing an
3598 <     * exception encountered in the application of a supplied
3599 <     * function. Bear in mind when handling such exceptions that other
3600 <     * concurrently executing functions could also have thrown
3601 <     * exceptions, or would have done so if the first exception had
3602 <     * not occurred.
3603 <     *
3604 <     * <p>Parallel speedups compared to sequential processing are
3605 <     * common but not guaranteed.  Operations involving brief
3606 <     * functions on small maps may execute more slowly than sequential
3607 <     * loops if the underlying work to parallelize the computation is
3608 <     * more expensive than the computation itself. Similarly,
3609 <     * parallelization may not lead to much actual parallelism if all
3610 <     * processors are busy performing unrelated tasks.
3611 <     *
3612 <     * <p> All arguments to all task methods must be non-null.
3613 <     *
3614 <     * <p><em>jsr166e note: During transition, this class
3615 <     * uses nested functional interfaces with different names but the
3616 <     * same forms as those expected for JDK8.<em>
2521 >     * Nodes for use in TreeBins
2522       */
2523 <    public class Parallel {
2524 <        final ForkJoinPool fjp;
2523 >    static final class TreeNode<K,V> extends Node<K,V> {
2524 >        TreeNode<K,V> parent;  // red-black tree links
2525 >        TreeNode<K,V> left;
2526 >        TreeNode<K,V> right;
2527 >        TreeNode<K,V> prev;    // needed to unlink next upon deletion
2528 >        boolean red;
2529  
2530 <        /**
2531 <         * Returns an extended view of this map using the given
2532 <         * executor for bulk parallel operations.
2533 <         *
3625 <         * @param executor the executor
3626 <         */
3627 <        public Parallel(ForkJoinPool executor)  {
3628 <            this.fjp = executor;
2530 >        TreeNode(int hash, K key, V val, Node<K,V> next,
2531 >                 TreeNode<K,V> parent) {
2532 >            super(hash, key, val, next);
2533 >            this.parent = parent;
2534          }
2535  
2536 <        /**
2537 <         * Performs the given action for each (key, value).
3633 <         *
3634 <         * @param action the action
3635 <         */
3636 <        public void forEach(BiAction<K,V> action) {
3637 <            fjp.invoke(ForkJoinTasks.forEach
3638 <                       (ConcurrentHashMapV8.this, action));
2536 >        Node<K,V> find(int h, Object k) {
2537 >            return findTreeNode(h, k, null);
2538          }
2539  
2540          /**
2541 <         * Performs the given action for each non-null transformation
2542 <         * of each (key, value).
3644 <         *
3645 <         * @param transformer a function returning the transformation
3646 <         * for an element, or null of there is no transformation (in
3647 <         * which case the action is not applied).
3648 <         * @param action the action
2541 >         * Returns the TreeNode (or null if not found) for the given key
2542 >         * starting at given root.
2543           */
2544 <        public <U> void forEach(BiFun<? super K, ? super V, ? extends U> transformer,
2545 <                                Action<U> action) {
2546 <            fjp.invoke(ForkJoinTasks.forEach
2547 <                       (ConcurrentHashMapV8.this, transformer, action));
2544 >        final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2545 >            if (k != null) {
2546 >                TreeNode<K,V> p = this;
2547 >                do  {
2548 >                    int ph, dir; K pk; TreeNode<K,V> q;
2549 >                    TreeNode<K,V> pl = p.left, pr = p.right;
2550 >                    if ((ph = p.hash) > h)
2551 >                        p = pl;
2552 >                    else if (ph < h)
2553 >                        p = pr;
2554 >                    else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2555 >                        return p;
2556 >                    else if (pl == null)
2557 >                        p = pr;
2558 >                    else if (pr == null)
2559 >                        p = pl;
2560 >                    else if ((kc != null ||
2561 >                              (kc = comparableClassFor(k)) != null) &&
2562 >                             (dir = compareComparables(kc, k, pk)) != 0)
2563 >                        p = (dir < 0) ? pl : pr;
2564 >                    else if ((q = pr.findTreeNode(h, k, kc)) != null)
2565 >                        return q;
2566 >                    else
2567 >                        p = pl;
2568 >                } while (p != null);
2569 >            }
2570 >            return null;
2571          }
2572 +    }
2573  
2574 <        /**
2575 <         * Returns a non-null result from applying the given search
2576 <         * function on each (key, value), or null if none.  Upon
2577 <         * success, further element processing is suppressed and the
2578 <         * results of any other parallel invocations of the search
2579 <         * function are ignored.
2580 <         *
2581 <         * @param searchFunction a function returning a non-null
2582 <         * result on success, else null
2583 <         * @return a non-null result from applying the given search
2584 <         * function on each (key, value), or null if none
2585 <         */
2586 <        public <U> U search(BiFun<? super K, ? super V, ? extends U> searchFunction) {
2587 <            return fjp.invoke(ForkJoinTasks.search
2588 <                              (ConcurrentHashMapV8.this, searchFunction));
2574 >    /* ---------------- TreeBins -------------- */
2575 >
2576 >    /**
2577 >     * TreeNodes used at the heads of bins. TreeBins do not hold user
2578 >     * keys or values, but instead point to list of TreeNodes and
2579 >     * their root. They also maintain a parasitic read-write lock
2580 >     * forcing writers (who hold bin lock) to wait for readers (who do
2581 >     * not) to complete before tree restructuring operations.
2582 >     */
2583 >    static final class TreeBin<K,V> extends Node<K,V> {
2584 >        TreeNode<K,V> root;
2585 >        volatile TreeNode<K,V> first;
2586 >        volatile Thread waiter;
2587 >        volatile int lockState;
2588 >        // values for lockState
2589 >        static final int WRITER = 1; // set while holding write lock
2590 >        static final int WAITER = 2; // set when waiting for write lock
2591 >        static final int READER = 4; // increment value for setting read lock
2592 >
2593 >        /**
2594 >         * Tie-breaking utility for ordering insertions when equal
2595 >         * hashCodes and non-comparable. We don't require a total
2596 >         * order, just a consistent insertion rule to maintain
2597 >         * equivalence across rebalancings. Tie-breaking further than
2598 >         * necessary simplifies testing a bit.
2599 >         */
2600 >        static int tieBreakOrder(Object a, Object b) {
2601 >            int d;
2602 >            if (a == null || b == null ||
2603 >                (d = a.getClass().getName().
2604 >                 compareTo(b.getClass().getName())) == 0)
2605 >                d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2606 >                     -1 : 1);
2607 >            return d;
2608          }
2609  
2610          /**
2611 <         * Returns the result of accumulating the given transformation
2612 <         * of all (key, value) pairs using the given reducer to
2613 <         * combine values, or null if none.
2614 <         *
2615 <         * @param transformer a function returning the transformation
2616 <         * for an element, or null of there is no transformation (in
2617 <         * which case it is not combined).
2618 <         * @param reducer a commutative associative combining function
2619 <         * @return the result of accumulating the given transformation
2620 <         * of all (key, value) pairs
2621 <         */
2622 <        public <U> U reduce(BiFun<? super K, ? super V, ? extends U> transformer,
2623 <                            BiFun<? super U, ? super U, ? extends U> reducer) {
2624 <            return fjp.invoke(ForkJoinTasks.reduce
2625 <                              (ConcurrentHashMapV8.this, transformer, reducer));
2611 >         * Creates bin with initial set of nodes headed by b.
2612 >         */
2613 >        TreeBin(TreeNode<K,V> b) {
2614 >            super(TREEBIN, null, null, null);
2615 >            this.first = b;
2616 >            TreeNode<K,V> r = null;
2617 >            for (TreeNode<K,V> x = b, next; x != null; x = next) {
2618 >                next = (TreeNode<K,V>)x.next;
2619 >                x.left = x.right = null;
2620 >                if (r == null) {
2621 >                    x.parent = null;
2622 >                    x.red = false;
2623 >                    r = x;
2624 >                }
2625 >                else {
2626 >                    K k = x.key;
2627 >                    int h = x.hash;
2628 >                    Class<?> kc = null;
2629 >                    for (TreeNode<K,V> p = r;;) {
2630 >                        int dir, ph;
2631 >                        K pk = p.key;
2632 >                        if ((ph = p.hash) > h)
2633 >                            dir = -1;
2634 >                        else if (ph < h)
2635 >                            dir = 1;
2636 >                        else if ((kc == null &&
2637 >                                  (kc = comparableClassFor(k)) == null) ||
2638 >                                 (dir = compareComparables(kc, k, pk)) == 0)
2639 >                            dir = tieBreakOrder(k, pk);
2640 >                            TreeNode<K,V> xp = p;
2641 >                        if ((p = (dir <= 0) ? p.left : p.right) == null) {
2642 >                            x.parent = xp;
2643 >                            if (dir <= 0)
2644 >                                xp.left = x;
2645 >                            else
2646 >                                xp.right = x;
2647 >                            r = balanceInsertion(r, x);
2648 >                            break;
2649 >                        }
2650 >                    }
2651 >                }
2652 >            }
2653 >            this.root = r;
2654 >            assert checkInvariants(root);
2655          }
2656  
2657          /**
2658 <         * Returns the result of accumulating the given transformation
3693 <         * of all (key, value) pairs using the given reducer to
3694 <         * combine values, and the given basis as an identity value.
3695 <         *
3696 <         * @param transformer a function returning the transformation
3697 <         * for an element
3698 <         * @param basis the identity (initial default value) for the reduction
3699 <         * @param reducer a commutative associative combining function
3700 <         * @return the result of accumulating the given transformation
3701 <         * of all (key, value) pairs
2658 >         * Acquires write lock for tree restructuring.
2659           */
2660 <        public double reduceToDouble(ObjectByObjectToDouble<? super K, ? super V> transformer,
2661 <                                     double basis,
2662 <                                     DoubleByDoubleToDouble reducer) {
3706 <            return fjp.invoke(ForkJoinTasks.reduceToDouble
3707 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
2660 >        private final void lockRoot() {
2661 >            if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2662 >                contendedLock(); // offload to separate method
2663          }
2664  
2665          /**
2666 <         * Returns the result of accumulating the given transformation
3712 <         * of all (key, value) pairs using the given reducer to
3713 <         * combine values, and the given basis as an identity value.
3714 <         *
3715 <         * @param transformer a function returning the transformation
3716 <         * for an element
3717 <         * @param basis the identity (initial default value) for the reduction
3718 <         * @param reducer a commutative associative combining function
3719 <         * @return the result of accumulating the given transformation
3720 <         * of all (key, value) pairs
2666 >         * Releases write lock for tree restructuring.
2667           */
2668 <        public long reduceToLong(ObjectByObjectToLong<? super K, ? super V> transformer,
2669 <                                 long basis,
3724 <                                 LongByLongToLong reducer) {
3725 <            return fjp.invoke(ForkJoinTasks.reduceToLong
3726 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
2668 >        private final void unlockRoot() {
2669 >            lockState = 0;
2670          }
2671  
2672          /**
2673 <         * Returns the result of accumulating the given transformation
3731 <         * of all (key, value) pairs using the given reducer to
3732 <         * combine values, and the given basis as an identity value.
3733 <         *
3734 <         * @param transformer a function returning the transformation
3735 <         * for an element
3736 <         * @param basis the identity (initial default value) for the reduction
3737 <         * @param reducer a commutative associative combining function
3738 <         * @return the result of accumulating the given transformation
3739 <         * of all (key, value) pairs
2673 >         * Possibly blocks awaiting root lock.
2674           */
2675 <        public int reduceToInt(ObjectByObjectToInt<? super K, ? super V> transformer,
2676 <                               int basis,
2677 <                               IntByIntToInt reducer) {
2678 <            return fjp.invoke(ForkJoinTasks.reduceToInt
2679 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
2675 >        private final void contendedLock() {
2676 >            boolean waiting = false;
2677 >            for (int s;;) {
2678 >                if (((s = lockState) & WRITER) == 0) {
2679 >                    if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2680 >                        if (waiting)
2681 >                            waiter = null;
2682 >                        return;
2683 >                    }
2684 >                }
2685 >                else if ((s | WAITER) == 0) {
2686 >                    if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2687 >                        waiting = true;
2688 >                        waiter = Thread.currentThread();
2689 >                    }
2690 >                }
2691 >                else if (waiting)
2692 >                    LockSupport.park(this);
2693 >            }
2694          }
2695  
2696          /**
2697 <         * Performs the given action for each key.
2698 <         *
2699 <         * @param action the action
2697 >         * Returns matching node or null if none. Tries to search
2698 >         * using tree comparisons from root, but continues linear
2699 >         * search when lock not available.
2700           */
2701 <        public void forEachKey(Action<K> action) {
2702 <            fjp.invoke(ForkJoinTasks.forEachKey
2703 <                       (ConcurrentHashMapV8.this, action));
2701 > final Node<K,V> find(int h, Object k) {
2702 >            if (k != null) {
2703 >                for (Node<K,V> e = first; e != null; e = e.next) {
2704 >                    int s; K ek;
2705 >                    if (((s = lockState) & (WAITER|WRITER)) != 0) {
2706 >                        if (e.hash == h &&
2707 >                            ((ek = e.key) == k || (ek != null && k.equals(ek))))
2708 >                            return e;
2709 >                    }
2710 >                    else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2711 >                                                 s + READER)) {
2712 >                        TreeNode<K,V> r, p;
2713 >                        try {
2714 >                            p = ((r = root) == null ? null :
2715 >                                 r.findTreeNode(h, k, null));
2716 >                        } finally {
2717 >                            Thread w;
2718 >                            int ls;
2719 >                            do {} while (!U.compareAndSwapInt
2720 >                                         (this, LOCKSTATE,
2721 >                                          ls = lockState, ls - READER));
2722 >                            if (ls == (READER|WAITER) && (w = waiter) != null)
2723 >                                LockSupport.unpark(w);
2724 >                        }
2725 >                        return p;
2726 >                    }
2727 >                }
2728 >            }
2729 >            return null;
2730          }
2731  
2732          /**
2733 <         * Performs the given action for each non-null transformation
2734 <         * of each key.
3761 <         *
3762 <         * @param transformer a function returning the transformation
3763 <         * for an element, or null of there is no transformation (in
3764 <         * which case the action is not applied).
3765 <         * @param action the action
2733 >         * Finds or adds a node.
2734 >         * @return null if added
2735           */
2736 <        public <U> void forEachKey(Fun<? super K, ? extends U> transformer,
2737 <                                   Action<U> action) {
2738 <            fjp.invoke(ForkJoinTasks.forEachKey
2739 <                       (ConcurrentHashMapV8.this, transformer, action));
2736 >        final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2737 >            Class<?> kc = null;
2738 >            boolean searched = false;
2739 >            for (TreeNode<K,V> p = root;;) {
2740 >                int dir, ph; K pk;
2741 >                if (p == null) {
2742 >                    first = root = new TreeNode<K,V>(h, k, v, null, null);
2743 >                    break;
2744 >                }
2745 >                else if ((ph = p.hash) > h)
2746 >                    dir = -1;
2747 >                else if (ph < h)
2748 >                    dir = 1;
2749 >                else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2750 >                    return p;
2751 >                else if ((kc == null &&
2752 >                          (kc = comparableClassFor(k)) == null) ||
2753 >                         (dir = compareComparables(kc, k, pk)) == 0) {
2754 >                    if (!searched) {
2755 >                        TreeNode<K,V> q, ch;
2756 >                        searched = true;
2757 >                        if (((ch = p.left) != null &&
2758 >                             (q = ch.findTreeNode(h, k, kc)) != null) ||
2759 >                            ((ch = p.right) != null &&
2760 >                             (q = ch.findTreeNode(h, k, kc)) != null))
2761 >                            return q;
2762 >                    }
2763 >                    dir = tieBreakOrder(k, pk);
2764 >                }
2765 >
2766 >                TreeNode<K,V> xp = p;
2767 >                if ((p = (dir <= 0) ? p.left : p.right) == null) {
2768 >                    TreeNode<K,V> x, f = first;
2769 >                    first = x = new TreeNode<K,V>(h, k, v, f, xp);
2770 >                    if (f != null)
2771 >                        f.prev = x;
2772 >                    if (dir <= 0)
2773 >                        xp.left = x;
2774 >                    else
2775 >                        xp.right = x;
2776 >                    if (!xp.red)
2777 >                        x.red = true;
2778 >                    else {
2779 >                        lockRoot();
2780 >                        try {
2781 >                            root = balanceInsertion(root, x);
2782 >                        } finally {
2783 >                            unlockRoot();
2784 >                        }
2785 >                    }
2786 >                    break;
2787 >                }
2788 >            }
2789 >            assert checkInvariants(root);
2790 >            return null;
2791          }
2792  
2793          /**
2794 <         * Returns a non-null result from applying the given search
2795 <         * function on each key, or null if none. Upon success,
2796 <         * further element processing is suppressed and the results of
2797 <         * any other parallel invocations of the search function are
2798 <         * ignored.
2794 >         * Removes the given node, that must be present before this
2795 >         * call.  This is messier than typical red-black deletion code
2796 >         * because we cannot swap the contents of an interior node
2797 >         * with a leaf successor that is pinned by "next" pointers
2798 >         * that are accessible independently of lock. So instead we
2799 >         * swap the tree linkages.
2800           *
2801 <         * @param searchFunction a function returning a non-null
3781 <         * result on success, else null
3782 <         * @return a non-null result from applying the given search
3783 <         * function on each key, or null if none
2801 >         * @return true if now too small, so should be untreeified
2802           */
2803 <        public <U> U searchKeys(Fun<? super K, ? extends U> searchFunction) {
2804 <            return fjp.invoke(ForkJoinTasks.searchKeys
2805 <                              (ConcurrentHashMapV8.this, searchFunction));
2803 >        final boolean removeTreeNode(TreeNode<K,V> p) {
2804 >            TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2805 >            TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2806 >            TreeNode<K,V> r, rl;
2807 >            if (pred == null)
2808 >                first = next;
2809 >            else
2810 >                pred.next = next;
2811 >            if (next != null)
2812 >                next.prev = pred;
2813 >            if (first == null) {
2814 >                root = null;
2815 >                return true;
2816 >            }
2817 >            if ((r = root) == null || r.right == null || // too small
2818 >                (rl = r.left) == null || rl.left == null)
2819 >                return true;
2820 >            lockRoot();
2821 >            try {
2822 >                TreeNode<K,V> replacement;
2823 >                TreeNode<K,V> pl = p.left;
2824 >                TreeNode<K,V> pr = p.right;
2825 >                if (pl != null && pr != null) {
2826 >                    TreeNode<K,V> s = pr, sl;
2827 >                    while ((sl = s.left) != null) // find successor
2828 >                        s = sl;
2829 >                    boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2830 >                    TreeNode<K,V> sr = s.right;
2831 >                    TreeNode<K,V> pp = p.parent;
2832 >                    if (s == pr) { // p was s's direct parent
2833 >                        p.parent = s;
2834 >                        s.right = p;
2835 >                    }
2836 >                    else {
2837 >                        TreeNode<K,V> sp = s.parent;
2838 >                        if ((p.parent = sp) != null) {
2839 >                            if (s == sp.left)
2840 >                                sp.left = p;
2841 >                            else
2842 >                                sp.right = p;
2843 >                        }
2844 >                        if ((s.right = pr) != null)
2845 >                            pr.parent = s;
2846 >                    }
2847 >                    p.left = null;
2848 >                    if ((p.right = sr) != null)
2849 >                        sr.parent = p;
2850 >                    if ((s.left = pl) != null)
2851 >                        pl.parent = s;
2852 >                    if ((s.parent = pp) == null)
2853 >                        r = s;
2854 >                    else if (p == pp.left)
2855 >                        pp.left = s;
2856 >                    else
2857 >                        pp.right = s;
2858 >                    if (sr != null)
2859 >                        replacement = sr;
2860 >                    else
2861 >                        replacement = p;
2862 >                }
2863 >                else if (pl != null)
2864 >                    replacement = pl;
2865 >                else if (pr != null)
2866 >                    replacement = pr;
2867 >                else
2868 >                    replacement = p;
2869 >                if (replacement != p) {
2870 >                    TreeNode<K,V> pp = replacement.parent = p.parent;
2871 >                    if (pp == null)
2872 >                        r = replacement;
2873 >                    else if (p == pp.left)
2874 >                        pp.left = replacement;
2875 >                    else
2876 >                        pp.right = replacement;
2877 >                    p.left = p.right = p.parent = null;
2878 >                }
2879 >
2880 >                root = (p.red) ? r : balanceDeletion(r, replacement);
2881 >
2882 >                if (p == replacement) {  // detach pointers
2883 >                    TreeNode<K,V> pp;
2884 >                    if ((pp = p.parent) != null) {
2885 >                        if (p == pp.left)
2886 >                            pp.left = null;
2887 >                        else if (p == pp.right)
2888 >                            pp.right = null;
2889 >                        p.parent = null;
2890 >                    }
2891 >                }
2892 >            } finally {
2893 >                unlockRoot();
2894 >            }
2895 >            assert checkInvariants(root);
2896 >            return false;
2897          }
2898  
2899 <        /**
2900 <         * Returns the result of accumulating all keys using the given
2901 <         * reducer to combine values, or null if none.
2902 <         *
2903 <         * @param reducer a commutative associative combining function
2904 <         * @return the result of accumulating all keys using the given
2905 <         * reducer to combine values, or null if none
2906 <         */
2907 <        public K reduceKeys(BiFun<? super K, ? super K, ? extends K> reducer) {
2908 <            return fjp.invoke(ForkJoinTasks.reduceKeys
2909 <                              (ConcurrentHashMapV8.this, reducer));
2899 >        /* ------------------------------------------------------------ */
2900 >        // Red-black tree methods, all adapted from CLR
2901 >
2902 >        static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2903 >                                              TreeNode<K,V> p) {
2904 >            TreeNode<K,V> r, pp, rl;
2905 >            if (p != null && (r = p.right) != null) {
2906 >                if ((rl = p.right = r.left) != null)
2907 >                    rl.parent = p;
2908 >                if ((pp = r.parent = p.parent) == null)
2909 >                    (root = r).red = false;
2910 >                else if (pp.left == p)
2911 >                    pp.left = r;
2912 >                else
2913 >                    pp.right = r;
2914 >                r.left = p;
2915 >                p.parent = r;
2916 >            }
2917 >            return root;
2918          }
2919  
2920 <        /**
2921 <         * Returns the result of accumulating the given transformation
2922 <         * of all keys using the given reducer to combine values, or
2923 <         * null if none.
2924 <         *
2925 <         * @param transformer a function returning the transformation
2926 <         * for an element, or null of there is no transformation (in
2927 <         * which case it is not combined).
2928 <         * @param reducer a commutative associative combining function
2929 <         * @return the result of accumulating the given transformation
2930 <         * of all keys
2931 <         */
2932 <        public <U> U reduceKeys(Fun<? super K, ? extends U> transformer,
2933 <                                BiFun<? super U, ? super U, ? extends U> reducer) {
2934 <            return fjp.invoke(ForkJoinTasks.reduceKeys
2935 <                              (ConcurrentHashMapV8.this, transformer, reducer));
2920 >        static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2921 >                                               TreeNode<K,V> p) {
2922 >            TreeNode<K,V> l, pp, lr;
2923 >            if (p != null && (l = p.left) != null) {
2924 >                if ((lr = p.left = l.right) != null)
2925 >                    lr.parent = p;
2926 >                if ((pp = l.parent = p.parent) == null)
2927 >                    (root = l).red = false;
2928 >                else if (pp.right == p)
2929 >                    pp.right = l;
2930 >                else
2931 >                    pp.left = l;
2932 >                l.right = p;
2933 >                p.parent = l;
2934 >            }
2935 >            return root;
2936          }
2937  
2938 <        /**
2939 <         * Returns the result of accumulating the given transformation
2940 <         * of all keys using the given reducer to combine values, and
2941 <         * the given basis as an identity value.
2942 <         *
2943 <         * @param transformer a function returning the transformation
2944 <         * for an element
2945 <         * @param basis the identity (initial default value) for the reduction
2946 <         * @param reducer a commutative associative combining function
2947 <         * @return  the result of accumulating the given transformation
2948 <         * of all keys
2949 <         */
2950 <        public double reduceKeysToDouble(ObjectToDouble<? super K> transformer,
2951 <                                         double basis,
2952 <                                         DoubleByDoubleToDouble reducer) {
2953 <            return fjp.invoke(ForkJoinTasks.reduceKeysToDouble
2954 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
2938 >        static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
2939 >                                                    TreeNode<K,V> x) {
2940 >            x.red = true;
2941 >            for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
2942 >                if ((xp = x.parent) == null) {
2943 >                    x.red = false;
2944 >                    return x;
2945 >                }
2946 >                else if (!xp.red || (xpp = xp.parent) == null)
2947 >                    return root;
2948 >                if (xp == (xppl = xpp.left)) {
2949 >                    if ((xppr = xpp.right) != null && xppr.red) {
2950 >                        xppr.red = false;
2951 >                        xp.red = false;
2952 >                        xpp.red = true;
2953 >                        x = xpp;
2954 >                    }
2955 >                    else {
2956 >                        if (x == xp.right) {
2957 >                            root = rotateLeft(root, x = xp);
2958 >                            xpp = (xp = x.parent) == null ? null : xp.parent;
2959 >                        }
2960 >                        if (xp != null) {
2961 >                            xp.red = false;
2962 >                            if (xpp != null) {
2963 >                                xpp.red = true;
2964 >                                root = rotateRight(root, xpp);
2965 >                            }
2966 >                        }
2967 >                    }
2968 >                }
2969 >                else {
2970 >                    if (xppl != null && xppl.red) {
2971 >                        xppl.red = false;
2972 >                        xp.red = false;
2973 >                        xpp.red = true;
2974 >                        x = xpp;
2975 >                    }
2976 >                    else {
2977 >                        if (x == xp.left) {
2978 >                            root = rotateRight(root, x = xp);
2979 >                            xpp = (xp = x.parent) == null ? null : xp.parent;
2980 >                        }
2981 >                        if (xp != null) {
2982 >                            xp.red = false;
2983 >                            if (xpp != null) {
2984 >                                xpp.red = true;
2985 >                                root = rotateLeft(root, xpp);
2986 >                            }
2987 >                        }
2988 >                    }
2989 >                }
2990 >            }
2991          }
2992  
2993 <        /**
2994 <         * Returns the result of accumulating the given transformation
2995 <         * of all keys using the given reducer to combine values, and
2996 <         * the given basis as an identity value.
2997 <         *
2998 <         * @param transformer a function returning the transformation
2999 <         * for an element
3000 <         * @param basis the identity (initial default value) for the reduction
3001 <         * @param reducer a commutative associative combining function
3002 <         * @return the result of accumulating the given transformation
3003 <         * of all keys
3004 <         */
3005 <        public long reduceKeysToLong(ObjectToLong<? super K> transformer,
3006 <                                     long basis,
3007 <                                     LongByLongToLong reducer) {
3008 <            return fjp.invoke(ForkJoinTasks.reduceKeysToLong
3009 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
2993 >        static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
2994 >                                                   TreeNode<K,V> x) {
2995 >            for (TreeNode<K,V> xp, xpl, xpr;;)  {
2996 >                if (x == null || x == root)
2997 >                    return root;
2998 >                else if ((xp = x.parent) == null) {
2999 >                    x.red = false;
3000 >                    return x;
3001 >                }
3002 >                else if (x.red) {
3003 >                    x.red = false;
3004 >                    return root;
3005 >                }
3006 >                else if ((xpl = xp.left) == x) {
3007 >                    if ((xpr = xp.right) != null && xpr.red) {
3008 >                        xpr.red = false;
3009 >                        xp.red = true;
3010 >                        root = rotateLeft(root, xp);
3011 >                        xpr = (xp = x.parent) == null ? null : xp.right;
3012 >                    }
3013 >                    if (xpr == null)
3014 >                        x = xp;
3015 >                    else {
3016 >                        TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3017 >                        if ((sr == null || !sr.red) &&
3018 >                            (sl == null || !sl.red)) {
3019 >                            xpr.red = true;
3020 >                            x = xp;
3021 >                        }
3022 >                        else {
3023 >                            if (sr == null || !sr.red) {
3024 >                                if (sl != null)
3025 >                                    sl.red = false;
3026 >                                xpr.red = true;
3027 >                                root = rotateRight(root, xpr);
3028 >                                xpr = (xp = x.parent) == null ?
3029 >                                    null : xp.right;
3030 >                            }
3031 >                            if (xpr != null) {
3032 >                                xpr.red = (xp == null) ? false : xp.red;
3033 >                                if ((sr = xpr.right) != null)
3034 >                                    sr.red = false;
3035 >                            }
3036 >                            if (xp != null) {
3037 >                                xp.red = false;
3038 >                                root = rotateLeft(root, xp);
3039 >                            }
3040 >                            x = root;
3041 >                        }
3042 >                    }
3043 >                }
3044 >                else { // symmetric
3045 >                    if (xpl != null && xpl.red) {
3046 >                        xpl.red = false;
3047 >                        xp.red = true;
3048 >                        root = rotateRight(root, xp);
3049 >                        xpl = (xp = x.parent) == null ? null : xp.left;
3050 >                    }
3051 >                    if (xpl == null)
3052 >                        x = xp;
3053 >                    else {
3054 >                        TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3055 >                        if ((sl == null || !sl.red) &&
3056 >                            (sr == null || !sr.red)) {
3057 >                            xpl.red = true;
3058 >                            x = xp;
3059 >                        }
3060 >                        else {
3061 >                            if (sl == null || !sl.red) {
3062 >                                if (sr != null)
3063 >                                    sr.red = false;
3064 >                                xpl.red = true;
3065 >                                root = rotateLeft(root, xpl);
3066 >                                xpl = (xp = x.parent) == null ?
3067 >                                    null : xp.left;
3068 >                            }
3069 >                            if (xpl != null) {
3070 >                                xpl.red = (xp == null) ? false : xp.red;
3071 >                                if ((sl = xpl.left) != null)
3072 >                                    sl.red = false;
3073 >                            }
3074 >                            if (xp != null) {
3075 >                                xp.red = false;
3076 >                                root = rotateRight(root, xp);
3077 >                            }
3078 >                            x = root;
3079 >                        }
3080 >                    }
3081 >                }
3082 >            }
3083          }
3084  
3085          /**
3086 <         * Returns the result of accumulating the given transformation
3861 <         * of all keys using the given reducer to combine values, and
3862 <         * the given basis as an identity value.
3863 <         *
3864 <         * @param transformer a function returning the transformation
3865 <         * for an element
3866 <         * @param basis the identity (initial default value) for the reduction
3867 <         * @param reducer a commutative associative combining function
3868 <         * @return the result of accumulating the given transformation
3869 <         * of all keys
3086 >         * Recursive invariant check
3087           */
3088 <        public int reduceKeysToInt(ObjectToInt<? super K> transformer,
3089 <                                   int basis,
3090 <                                   IntByIntToInt reducer) {
3091 <            return fjp.invoke(ForkJoinTasks.reduceKeysToInt
3092 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3088 >        static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3089 >            TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3090 >                tb = t.prev, tn = (TreeNode<K,V>)t.next;
3091 >            if (tb != null && tb.next != t)
3092 >                return false;
3093 >            if (tn != null && tn.prev != t)
3094 >                return false;
3095 >            if (tp != null && t != tp.left && t != tp.right)
3096 >                return false;
3097 >            if (tl != null && (tl.parent != t || tl.hash > t.hash))
3098 >                return false;
3099 >            if (tr != null && (tr.parent != t || tr.hash < t.hash))
3100 >                return false;
3101 >            if (t.red && tl != null && tl.red && tr != null && tr.red)
3102 >                return false;
3103 >            if (tl != null && !checkInvariants(tl))
3104 >                return false;
3105 >            if (tr != null && !checkInvariants(tr))
3106 >                return false;
3107 >            return true;
3108          }
3109  
3110 <        /**
3111 <         * Performs the given action for each value.
3112 <         *
3113 <         * @param action the action
3114 <         */
3115 <        public void forEachValue(Action<V> action) {
3116 <            fjp.invoke(ForkJoinTasks.forEachValue
3117 <                       (ConcurrentHashMapV8.this, action));
3110 >        private static final sun.misc.Unsafe U;
3111 >        private static final long LOCKSTATE;
3112 >        static {
3113 >            try {
3114 >                U = getUnsafe();
3115 >                Class<?> k = TreeBin.class;
3116 >                LOCKSTATE = U.objectFieldOffset
3117 >                    (k.getDeclaredField("lockState"));
3118 >            } catch (Exception e) {
3119 >                throw new Error(e);
3120 >            }
3121          }
3122 +    }
3123  
3124 <        /**
3125 <         * Performs the given action for each non-null transformation
3126 <         * of each value.
3127 <         *
3128 <         * @param transformer a function returning the transformation
3129 <         * for an element, or null of there is no transformation (in
3130 <         * which case the action is not applied).
3131 <         */
3132 <        public <U> void forEachValue(Fun<? super V, ? extends U> transformer,
3133 <                                     Action<U> action) {
3134 <            fjp.invoke(ForkJoinTasks.forEachValue
3135 <                       (ConcurrentHashMapV8.this, transformer, action));
3124 >    /* ----------------Table Traversal -------------- */
3125 >
3126 >    /**
3127 >     * Encapsulates traversal for methods such as containsValue; also
3128 >     * serves as a base class for other iterators and spliterators.
3129 >     *
3130 >     * Method advance visits once each still-valid node that was
3131 >     * reachable upon iterator construction. It might miss some that
3132 >     * were added to a bin after the bin was visited, which is OK wrt
3133 >     * consistency guarantees. Maintaining this property in the face
3134 >     * of possible ongoing resizes requires a fair amount of
3135 >     * bookkeeping state that is difficult to optimize away amidst
3136 >     * volatile accesses.  Even so, traversal maintains reasonable
3137 >     * throughput.
3138 >     *
3139 >     * Normally, iteration proceeds bin-by-bin traversing lists.
3140 >     * However, if the table has been resized, then all future steps
3141 >     * must traverse both the bin at the current index as well as at
3142 >     * (index + baseSize); and so on for further resizings. To
3143 >     * paranoically cope with potential sharing by users of iterators
3144 >     * across threads, iteration terminates if a bounds checks fails
3145 >     * for a table read.
3146 >     */
3147 >    static class Traverser<K,V> {
3148 >        Node<K,V>[] tab;        // current table; updated if resized
3149 >        Node<K,V> next;         // the next entry to use
3150 >        int index;              // index of bin to use next
3151 >        int baseIndex;          // current index of initial table
3152 >        int baseLimit;          // index bound for initial table
3153 >        final int baseSize;     // initial table size
3154 >
3155 >        Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3156 >            this.tab = tab;
3157 >            this.baseSize = size;
3158 >            this.baseIndex = this.index = index;
3159 >            this.baseLimit = limit;
3160 >            this.next = null;
3161          }
3162  
3163          /**
3164 <         * Returns a non-null result from applying the given search
3165 <         * function on each value, or null if none.  Upon success,
3166 <         * further element processing is suppressed and the results of
3167 <         * any other parallel invocations of the search function are
3168 <         * ignored.
3169 <         *
3170 <         * @param searchFunction a function returning a non-null
3171 <         * result on success, else null
3172 <         * @return a non-null result from applying the given search
3173 <         * function on each value, or null if none
3174 <         *
3175 <         */
3176 <        public <U> U searchValues(Fun<? super V, ? extends U> searchFunction) {
3177 <            return fjp.invoke(ForkJoinTasks.searchValues
3178 <                              (ConcurrentHashMapV8.this, searchFunction));
3164 >         * Advances if possible, returning next valid node, or null if none.
3165 >         */
3166 >        final Node<K,V> advance() {
3167 >            Node<K,V> e;
3168 >            if ((e = next) != null)
3169 >                e = e.next;
3170 >            for (;;) {
3171 >                Node<K,V>[] t; int i, n; K ek;  // must use locals in checks
3172 >                if (e != null)
3173 >                    return next = e;
3174 >                if (baseIndex >= baseLimit || (t = tab) == null ||
3175 >                    (n = t.length) <= (i = index) || i < 0)
3176 >                    return next = null;
3177 >                if ((e = tabAt(t, index)) != null && e.hash < 0) {
3178 >                    if (e instanceof ForwardingNode) {
3179 >                        tab = ((ForwardingNode<K,V>)e).nextTable;
3180 >                        e = null;
3181 >                        continue;
3182 >                    }
3183 >                    else if (e instanceof TreeBin)
3184 >                        e = ((TreeBin<K,V>)e).first;
3185 >                    else
3186 >                        e = null;
3187 >                }
3188 >                if ((index += baseSize) >= n)
3189 >                    index = ++baseIndex;    // visit upper slots if present
3190 >            }
3191          }
3192 +    }
3193  
3194 <        /**
3195 <         * Returns the result of accumulating all values using the
3196 <         * given reducer to combine values, or null if none.
3197 <         *
3198 <         * @param reducer a commutative associative combining function
3199 <         * @return  the result of accumulating all values
3200 <         */
3201 <        public V reduceValues(BiFun<? super V, ? super V, ? extends V> reducer) {
3202 <            return fjp.invoke(ForkJoinTasks.reduceValues
3203 <                              (ConcurrentHashMapV8.this, reducer));
3194 >    /**
3195 >     * Base of key, value, and entry Iterators. Adds fields to
3196 >     * Traverser to support iterator.remove.
3197 >     */
3198 >    static class BaseIterator<K,V> extends Traverser<K,V> {
3199 >        final ConcurrentHashMapV8<K,V> map;
3200 >        Node<K,V> lastReturned;
3201 >        BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3202 >                    ConcurrentHashMapV8<K,V> map) {
3203 >            super(tab, size, index, limit);
3204 >            this.map = map;
3205 >            advance();
3206          }
3207  
3208 <        /**
3209 <         * Returns the result of accumulating the given transformation
3210 <         * of all values using the given reducer to combine values, or
3211 <         * null if none.
3212 <         *
3213 <         * @param transformer a function returning the transformation
3214 <         * for an element, or null of there is no transformation (in
3215 <         * which case it is not combined).
3216 <         * @param reducer a commutative associative combining function
3941 <         * @return the result of accumulating the given transformation
3942 <         * of all values
3943 <         */
3944 <        public <U> U reduceValues(Fun<? super V, ? extends U> transformer,
3945 <                                  BiFun<? super U, ? super U, ? extends U> reducer) {
3946 <            return fjp.invoke(ForkJoinTasks.reduceValues
3947 <                              (ConcurrentHashMapV8.this, transformer, reducer));
3208 >        public final boolean hasNext() { return next != null; }
3209 >        public final boolean hasMoreElements() { return next != null; }
3210 >
3211 >        public final void remove() {
3212 >            Node<K,V> p;
3213 >            if ((p = lastReturned) == null)
3214 >                throw new IllegalStateException();
3215 >            lastReturned = null;
3216 >            map.replaceNode(p.key, null, null);
3217          }
3218 +    }
3219  
3220 <        /**
3221 <         * Returns the result of accumulating the given transformation
3222 <         * of all values using the given reducer to combine values,
3223 <         * and the given basis as an identity value.
3224 <         *
3955 <         * @param transformer a function returning the transformation
3956 <         * for an element
3957 <         * @param basis the identity (initial default value) for the reduction
3958 <         * @param reducer a commutative associative combining function
3959 <         * @return the result of accumulating the given transformation
3960 <         * of all values
3961 <         */
3962 <        public double reduceValuesToDouble(ObjectToDouble<? super V> transformer,
3963 <                                           double basis,
3964 <                                           DoubleByDoubleToDouble reducer) {
3965 <            return fjp.invoke(ForkJoinTasks.reduceValuesToDouble
3966 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3220 >    static final class KeyIterator<K,V> extends BaseIterator<K,V>
3221 >        implements Iterator<K>, Enumeration<K> {
3222 >        KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3223 >                    ConcurrentHashMapV8<K,V> map) {
3224 >            super(tab, index, size, limit, map);
3225          }
3226  
3227 <        /**
3228 <         * Returns the result of accumulating the given transformation
3229 <         * of all values using the given reducer to combine values,
3230 <         * and the given basis as an identity value.
3231 <         *
3232 <         * @param transformer a function returning the transformation
3233 <         * for an element
3234 <         * @param basis the identity (initial default value) for the reduction
3977 <         * @param reducer a commutative associative combining function
3978 <         * @return the result of accumulating the given transformation
3979 <         * of all values
3980 <         */
3981 <        public long reduceValuesToLong(ObjectToLong<? super V> transformer,
3982 <                                       long basis,
3983 <                                       LongByLongToLong reducer) {
3984 <            return fjp.invoke(ForkJoinTasks.reduceValuesToLong
3985 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3227 >        public final K next() {
3228 >            Node<K,V> p;
3229 >            if ((p = next) == null)
3230 >                throw new NoSuchElementException();
3231 >            K k = p.key;
3232 >            lastReturned = p;
3233 >            advance();
3234 >            return k;
3235          }
3236  
3237 <        /**
3238 <         * Returns the result of accumulating the given transformation
3239 <         * of all values using the given reducer to combine values,
3240 <         * and the given basis as an identity value.
3241 <         *
3242 <         * @param transformer a function returning the transformation
3243 <         * for an element
3244 <         * @param basis the identity (initial default value) for the reduction
3996 <         * @param reducer a commutative associative combining function
3997 <         * @return the result of accumulating the given transformation
3998 <         * of all values
3999 <         */
4000 <        public int reduceValuesToInt(ObjectToInt<? super V> transformer,
4001 <                                     int basis,
4002 <                                     IntByIntToInt reducer) {
4003 <            return fjp.invoke(ForkJoinTasks.reduceValuesToInt
4004 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3237 >        public final K nextElement() { return next(); }
3238 >    }
3239 >
3240 >    static final class ValueIterator<K,V> extends BaseIterator<K,V>
3241 >        implements Iterator<V>, Enumeration<V> {
3242 >        ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3243 >                      ConcurrentHashMapV8<K,V> map) {
3244 >            super(tab, index, size, limit, map);
3245          }
3246  
3247 <        /**
3248 <         * Performs the given action for each entry.
3249 <         *
3250 <         * @param action the action
3251 <         */
3252 <        public void forEachEntry(Action<Map.Entry<K,V>> action) {
3253 <            fjp.invoke(ForkJoinTasks.forEachEntry
3254 <                       (ConcurrentHashMapV8.this, action));
3247 >        public final V next() {
3248 >            Node<K,V> p;
3249 >            if ((p = next) == null)
3250 >                throw new NoSuchElementException();
3251 >            V v = p.val;
3252 >            lastReturned = p;
3253 >            advance();
3254 >            return v;
3255          }
3256  
3257 <        /**
3258 <         * Performs the given action for each non-null transformation
3259 <         * of each entry.
3260 <         *
3261 <         * @param transformer a function returning the transformation
3262 <         * for an element, or null of there is no transformation (in
3263 <         * which case the action is not applied).
3264 <         * @param action the action
4025 <         */
4026 <        public <U> void forEachEntry(Fun<Map.Entry<K,V>, ? extends U> transformer,
4027 <                                     Action<U> action) {
4028 <            fjp.invoke(ForkJoinTasks.forEachEntry
4029 <                       (ConcurrentHashMapV8.this, transformer, action));
3257 >        public final V nextElement() { return next(); }
3258 >    }
3259 >
3260 >    static final class EntryIterator<K,V> extends BaseIterator<K,V>
3261 >        implements Iterator<Map.Entry<K,V>> {
3262 >        EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3263 >                      ConcurrentHashMapV8<K,V> map) {
3264 >            super(tab, index, size, limit, map);
3265          }
3266  
3267 <        /**
3268 <         * Returns a non-null result from applying the given search
3269 <         * function on each entry, or null if none.  Upon success,
3270 <         * further element processing is suppressed and the results of
3271 <         * any other parallel invocations of the search function are
3272 <         * ignored.
3273 <         *
3274 <         * @param searchFunction a function returning a non-null
3275 <         * result on success, else null
4041 <         * @return a non-null result from applying the given search
4042 <         * function on each entry, or null if none
4043 <         */
4044 <        public <U> U searchEntries(Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4045 <            return fjp.invoke(ForkJoinTasks.searchEntries
4046 <                              (ConcurrentHashMapV8.this, searchFunction));
3267 >        public final Map.Entry<K,V> next() {
3268 >            Node<K,V> p;
3269 >            if ((p = next) == null)
3270 >                throw new NoSuchElementException();
3271 >            K k = p.key;
3272 >            V v = p.val;
3273 >            lastReturned = p;
3274 >            advance();
3275 >            return new MapEntry<K,V>(k, v, map);
3276          }
3277 +    }
3278  
3279 <        /**
3280 <         * Returns the result of accumulating all entries using the
3281 <         * given reducer to combine values, or null if none.
3282 <         *
3283 <         * @param reducer a commutative associative combining function
3284 <         * @return the result of accumulating all entries
3285 <         */
3286 <        public Map.Entry<K,V> reduceEntries(BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3287 <            return fjp.invoke(ForkJoinTasks.reduceEntries
3288 <                              (ConcurrentHashMapV8.this, reducer));
3279 >    /**
3280 >     * Exported Entry for EntryIterator
3281 >     */
3282 >    static final class MapEntry<K,V> implements Map.Entry<K,V> {
3283 >        final K key; // non-null
3284 >        V val;       // non-null
3285 >        final ConcurrentHashMapV8<K,V> map;
3286 >        MapEntry(K key, V val, ConcurrentHashMapV8<K,V> map) {
3287 >            this.key = key;
3288 >            this.val = val;
3289 >            this.map = map;
3290          }
3291 +        public K getKey()        { return key; }
3292 +        public V getValue()      { return val; }
3293 +        public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3294 +        public String toString() { return key + "=" + val; }
3295  
3296 <        /**
3297 <         * Returns the result of accumulating the given transformation
3298 <         * of all entries using the given reducer to combine values,
3299 <         * or null if none.
3300 <         *
3301 <         * @param transformer a function returning the transformation
3302 <         * for an element, or null of there is no transformation (in
4068 <         * which case it is not combined).
4069 <         * @param reducer a commutative associative combining function
4070 <         * @return the result of accumulating the given transformation
4071 <         * of all entries
4072 <         */
4073 <        public <U> U reduceEntries(Fun<Map.Entry<K,V>, ? extends U> transformer,
4074 <                                   BiFun<? super U, ? super U, ? extends U> reducer) {
4075 <            return fjp.invoke(ForkJoinTasks.reduceEntries
4076 <                              (ConcurrentHashMapV8.this, transformer, reducer));
3296 >        public boolean equals(Object o) {
3297 >            Object k, v; Map.Entry<?,?> e;
3298 >            return ((o instanceof Map.Entry) &&
3299 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3300 >                    (v = e.getValue()) != null &&
3301 >                    (k == key || k.equals(key)) &&
3302 >                    (v == val || v.equals(val)));
3303          }
3304  
3305          /**
3306 <         * Returns the result of accumulating the given transformation
3307 <         * of all entries using the given reducer to combine values,
3308 <         * and the given basis as an identity value.
3309 <         *
3310 <         * @param transformer a function returning the transformation
3311 <         * for an element
4086 <         * @param basis the identity (initial default value) for the reduction
4087 <         * @param reducer a commutative associative combining function
4088 <         * @return the result of accumulating the given transformation
4089 <         * of all entries
3306 >         * Sets our entry's value and writes through to the map. The
3307 >         * value to return is somewhat arbitrary here. Since we do not
3308 >         * necessarily track asynchronous changes, the most recent
3309 >         * "previous" value could be different from what we return (or
3310 >         * could even have been removed, in which case the put will
3311 >         * re-establish). We do not and cannot guarantee more.
3312           */
3313 <        public double reduceEntriesToDouble(ObjectToDouble<Map.Entry<K,V>> transformer,
3314 <                                            double basis,
3315 <                                            DoubleByDoubleToDouble reducer) {
3316 <            return fjp.invoke(ForkJoinTasks.reduceEntriesToDouble
3317 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3313 >        public V setValue(V value) {
3314 >            if (value == null) throw new NullPointerException();
3315 >            V v = val;
3316 >            val = value;
3317 >            map.put(key, value);
3318 >            return v;
3319          }
3320 +    }
3321  
3322 <        /**
3323 <         * Returns the result of accumulating the given transformation
3324 <         * of all entries using the given reducer to combine values,
3325 <         * and the given basis as an identity value.
3326 <         *
3327 <         * @param transformer a function returning the transformation
3328 <         * for an element
3329 <         * @param basis the identity (initial default value) for the reduction
3330 <         * @param reducer a commutative associative combining function
3331 <         * @return  the result of accumulating the given transformation
3332 <         * of all entries
3333 <         */
3334 <        public long reduceEntriesToLong(ObjectToLong<Map.Entry<K,V>> transformer,
3335 <                                        long basis,
4112 <                                        LongByLongToLong reducer) {
4113 <            return fjp.invoke(ForkJoinTasks.reduceEntriesToLong
4114 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3322 >    static final class KeySpliterator<K,V> extends Traverser<K,V>
3323 >        implements ConcurrentHashMapSpliterator<K> {
3324 >        long est;               // size estimate
3325 >        KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3326 >                       long est) {
3327 >            super(tab, size, index, limit);
3328 >            this.est = est;
3329 >        }
3330 >
3331 >        public ConcurrentHashMapSpliterator<K> trySplit() {
3332 >            int i, f, h;
3333 >            return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3334 >                new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3335 >                                        f, est >>>= 1);
3336          }
3337  
3338 <        /**
3339 <         * Returns the result of accumulating the given transformation
3340 <         * of all entries using the given reducer to combine values,
3341 <         * and the given basis as an identity value.
4121 <         *
4122 <         * @param transformer a function returning the transformation
4123 <         * for an element
4124 <         * @param basis the identity (initial default value) for the reduction
4125 <         * @param reducer a commutative associative combining function
4126 <         * @return the result of accumulating the given transformation
4127 <         * of all entries
4128 <         */
4129 <        public int reduceEntriesToInt(ObjectToInt<Map.Entry<K,V>> transformer,
4130 <                                      int basis,
4131 <                                      IntByIntToInt reducer) {
4132 <            return fjp.invoke(ForkJoinTasks.reduceEntriesToInt
4133 <                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3338 >        public void forEachRemaining(Action<? super K> action) {
3339 >            if (action == null) throw new NullPointerException();
3340 >            for (Node<K,V> p; (p = advance()) != null;)
3341 >                action.apply(p.key);
3342          }
3343 +
3344 +        public boolean tryAdvance(Action<? super K> action) {
3345 +            if (action == null) throw new NullPointerException();
3346 +            Node<K,V> p;
3347 +            if ((p = advance()) == null)
3348 +                return false;
3349 +            action.apply(p.key);
3350 +            return true;
3351 +        }
3352 +
3353 +        public long estimateSize() { return est; }
3354 +
3355      }
3356  
3357 <    // ---------------------------------------------------------------------
3357 >    static final class ValueSpliterator<K,V> extends Traverser<K,V>
3358 >        implements ConcurrentHashMapSpliterator<V> {
3359 >        long est;               // size estimate
3360 >        ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3361 >                         long est) {
3362 >            super(tab, size, index, limit);
3363 >            this.est = est;
3364 >        }
3365  
3366 <    /**
3367 <     * Predefined tasks for performing bulk parallel operations on
3368 <     * ConcurrentHashMaps. These tasks follow the forms and rules used
3369 <     * in class {@link Parallel}. Each method has the same name, but
3370 <     * returns a task rather than invoking it. These methods may be
3371 <     * useful in custom applications such as submitting a task without
4145 <     * waiting for completion, or combining with other tasks.
4146 <     */
4147 <    public static class ForkJoinTasks {
4148 <        private ForkJoinTasks() {}
3366 >        public ConcurrentHashMapSpliterator<V> trySplit() {
3367 >            int i, f, h;
3368 >            return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3369 >                new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3370 >                                          f, est >>>= 1);
3371 >        }
3372  
3373 <        /**
4151 <         * Returns a task that when invoked, performs the given
4152 <         * action for each (key, value)
4153 <         *
4154 <         * @param map the map
4155 <         * @param action the action
4156 <         * @return the task
4157 <         */
4158 <        public static <K,V> ForkJoinTask<Void> forEach
4159 <            (ConcurrentHashMapV8<K,V> map,
4160 <             BiAction<K,V> action) {
3373 >        public void forEachRemaining(Action<? super V> action) {
3374              if (action == null) throw new NullPointerException();
3375 <            return new ForEachMappingTask<K,V>(map, action);
3375 >            for (Node<K,V> p; (p = advance()) != null;)
3376 >                action.apply(p.val);
3377          }
3378  
3379 <        /**
3380 <         * Returns a task that when invoked, performs the given
3381 <         * action for each non-null transformation of each (key, value)
3382 <         *
3383 <         * @param map the map
3384 <         * @param transformer a function returning the transformation
3385 <         * for an element, or null of there is no transformation (in
4172 <         * which case the action is not applied).
4173 <         * @param action the action
4174 <         * @return the task
4175 <         */
4176 <        public static <K,V,U> ForkJoinTask<Void> forEach
4177 <            (ConcurrentHashMapV8<K,V> map,
4178 <             BiFun<? super K, ? super V, ? extends U> transformer,
4179 <             Action<U> action) {
4180 <            if (transformer == null || action == null)
4181 <                throw new NullPointerException();
4182 <            return new ForEachTransformedMappingTask<K,V,U>
4183 <                (map, transformer, action);
3379 >        public boolean tryAdvance(Action<? super V> action) {
3380 >            if (action == null) throw new NullPointerException();
3381 >            Node<K,V> p;
3382 >            if ((p = advance()) == null)
3383 >                return false;
3384 >            action.apply(p.val);
3385 >            return true;
3386          }
3387  
3388 <        /**
3389 <         * Returns a task that when invoked, returns a non-null result
3390 <         * from applying the given search function on each (key,
3391 <         * value), or null if none. Upon success, further element
3392 <         * processing is suppressed and the results of any other
3393 <         * parallel invocations of the search function are ignored.
3394 <         *
3395 <         * @param map the map
3396 <         * @param searchFunction a function returning a non-null
3397 <         * result on success, else null
3398 <         * @return the task
3399 <         */
3400 <        public static <K,V,U> ForkJoinTask<U> search
4199 <            (ConcurrentHashMapV8<K,V> map,
4200 <             BiFun<? super K, ? super V, ? extends U> searchFunction) {
4201 <            if (searchFunction == null) throw new NullPointerException();
4202 <            return new SearchMappingsTask<K,V,U>
4203 <                (map, searchFunction,
4204 <                 new AtomicReference<U>());
3388 >        public long estimateSize() { return est; }
3389 >
3390 >    }
3391 >
3392 >    static final class EntrySpliterator<K,V> extends Traverser<K,V>
3393 >        implements ConcurrentHashMapSpliterator<Map.Entry<K,V>> {
3394 >        final ConcurrentHashMapV8<K,V> map; // To export MapEntry
3395 >        long est;               // size estimate
3396 >        EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3397 >                         long est, ConcurrentHashMapV8<K,V> map) {
3398 >            super(tab, size, index, limit);
3399 >            this.map = map;
3400 >            this.est = est;
3401          }
3402  
3403 <        /**
3404 <         * Returns a task that when invoked, returns the result of
3405 <         * accumulating the given transformation of all (key, value) pairs
3406 <         * using the given reducer to combine values, or null if none.
3407 <         *
4212 <         * @param map the map
4213 <         * @param transformer a function returning the transformation
4214 <         * for an element, or null of there is no transformation (in
4215 <         * which case it is not combined).
4216 <         * @param reducer a commutative associative combining function
4217 <         * @return the task
4218 <         */
4219 <        public static <K,V,U> ForkJoinTask<U> reduce
4220 <            (ConcurrentHashMapV8<K,V> map,
4221 <             BiFun<? super K, ? super V, ? extends U> transformer,
4222 <             BiFun<? super U, ? super U, ? extends U> reducer) {
4223 <            if (transformer == null || reducer == null)
4224 <                throw new NullPointerException();
4225 <            return new MapReduceMappingsTask<K,V,U>
4226 <                (map, transformer, reducer);
3403 >        public ConcurrentHashMapSpliterator<Map.Entry<K,V>> trySplit() {
3404 >            int i, f, h;
3405 >            return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3406 >                new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3407 >                                          f, est >>>= 1, map);
3408          }
3409  
3410 <        /**
3411 <         * Returns a task that when invoked, returns the result of
3412 <         * accumulating the given transformation of all (key, value) pairs
3413 <         * using the given reducer to combine values, and the given
4233 <         * basis as an identity value.
4234 <         *
4235 <         * @param map the map
4236 <         * @param transformer a function returning the transformation
4237 <         * for an element
4238 <         * @param basis the identity (initial default value) for the reduction
4239 <         * @param reducer a commutative associative combining function
4240 <         * @return the task
4241 <         */
4242 <        public static <K,V> ForkJoinTask<Double> reduceToDouble
4243 <            (ConcurrentHashMapV8<K,V> map,
4244 <             ObjectByObjectToDouble<? super K, ? super V> transformer,
4245 <             double basis,
4246 <             DoubleByDoubleToDouble reducer) {
4247 <            if (transformer == null || reducer == null)
4248 <                throw new NullPointerException();
4249 <            return new MapReduceMappingsToDoubleTask<K,V>
4250 <                (map, transformer, basis, reducer);
3410 >        public void forEachRemaining(Action<? super Map.Entry<K,V>> action) {
3411 >            if (action == null) throw new NullPointerException();
3412 >            for (Node<K,V> p; (p = advance()) != null; )
3413 >                action.apply(new MapEntry<K,V>(p.key, p.val, map));
3414          }
3415  
3416 <        /**
3417 <         * Returns a task that when invoked, returns the result of
3418 <         * accumulating the given transformation of all (key, value) pairs
3419 <         * using the given reducer to combine values, and the given
3420 <         * basis as an identity value.
3421 <         *
3422 <         * @param map the map
4260 <         * @param transformer a function returning the transformation
4261 <         * for an element
4262 <         * @param basis the identity (initial default value) for the reduction
4263 <         * @param reducer a commutative associative combining function
4264 <         * @return the task
4265 <         */
4266 <        public static <K,V> ForkJoinTask<Long> reduceToLong
4267 <            (ConcurrentHashMapV8<K,V> map,
4268 <             ObjectByObjectToLong<? super K, ? super V> transformer,
4269 <             long basis,
4270 <             LongByLongToLong reducer) {
4271 <            if (transformer == null || reducer == null)
4272 <                throw new NullPointerException();
4273 <            return new MapReduceMappingsToLongTask<K,V>
4274 <                (map, transformer, basis, reducer);
3416 >        public boolean tryAdvance(Action<? super Map.Entry<K,V>> action) {
3417 >            if (action == null) throw new NullPointerException();
3418 >            Node<K,V> p;
3419 >            if ((p = advance()) == null)
3420 >                return false;
3421 >            action.apply(new MapEntry<K,V>(p.key, p.val, map));
3422 >            return true;
3423          }
3424  
3425 +        public long estimateSize() { return est; }
3426 +
3427 +    }
3428 +
3429 +    // Parallel bulk operations
3430 +
3431 +    /**
3432 +     * Computes initial batch value for bulk tasks. The returned value
3433 +     * is approximately exp2 of the number of times (minus one) to
3434 +     * split task by two before executing leaf action. This value is
3435 +     * faster to compute and more convenient to use as a guide to
3436 +     * splitting than is the depth, since it is used while dividing by
3437 +     * two anyway.
3438 +     */
3439 +    final int batchFor(long b) {
3440 +        long n;
3441 +        if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3442 +            return 0;
3443 +        int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3444 +        return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3445 +    }
3446 +
3447 +    /**
3448 +     * Performs the given action for each (key, value).
3449 +     *
3450 +     * @param parallelismThreshold the (estimated) number of elements
3451 +     * needed for this operation to be executed in parallel
3452 +     * @param action the action
3453 +     * @since 1.8
3454 +     */
3455 +    public void forEach(long parallelismThreshold,
3456 +                        BiAction<? super K,? super V> action) {
3457 +        if (action == null) throw new NullPointerException();
3458 +        new ForEachMappingTask<K,V>
3459 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3460 +             action).invoke();
3461 +    }
3462 +
3463 +    /**
3464 +     * Performs the given action for each non-null transformation
3465 +     * of each (key, value).
3466 +     *
3467 +     * @param parallelismThreshold the (estimated) number of elements
3468 +     * needed for this operation to be executed in parallel
3469 +     * @param transformer a function returning the transformation
3470 +     * for an element, or null if there is no transformation (in
3471 +     * which case the action is not applied)
3472 +     * @param action the action
3473 +     * @since 1.8
3474 +     */
3475 +    public <U> void forEach(long parallelismThreshold,
3476 +                            BiFun<? super K, ? super V, ? extends U> transformer,
3477 +                            Action<? super U> action) {
3478 +        if (transformer == null || action == null)
3479 +            throw new NullPointerException();
3480 +        new ForEachTransformedMappingTask<K,V,U>
3481 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3482 +             transformer, action).invoke();
3483 +    }
3484 +
3485 +    /**
3486 +     * Returns a non-null result from applying the given search
3487 +     * function on each (key, value), or null if none.  Upon
3488 +     * success, further element processing is suppressed and the
3489 +     * results of any other parallel invocations of the search
3490 +     * function are ignored.
3491 +     *
3492 +     * @param parallelismThreshold the (estimated) number of elements
3493 +     * needed for this operation to be executed in parallel
3494 +     * @param searchFunction a function returning a non-null
3495 +     * result on success, else null
3496 +     * @return a non-null result from applying the given search
3497 +     * function on each (key, value), or null if none
3498 +     * @since 1.8
3499 +     */
3500 +    public <U> U search(long parallelismThreshold,
3501 +                        BiFun<? super K, ? super V, ? extends U> searchFunction) {
3502 +        if (searchFunction == null) throw new NullPointerException();
3503 +        return new SearchMappingsTask<K,V,U>
3504 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3505 +             searchFunction, new AtomicReference<U>()).invoke();
3506 +    }
3507 +
3508 +    /**
3509 +     * Returns the result of accumulating the given transformation
3510 +     * of all (key, value) pairs using the given reducer to
3511 +     * combine values, or null if none.
3512 +     *
3513 +     * @param parallelismThreshold the (estimated) number of elements
3514 +     * needed for this operation to be executed in parallel
3515 +     * @param transformer a function returning the transformation
3516 +     * for an element, or null if there is no transformation (in
3517 +     * which case it is not combined)
3518 +     * @param reducer a commutative associative combining function
3519 +     * @return the result of accumulating the given transformation
3520 +     * of all (key, value) pairs
3521 +     * @since 1.8
3522 +     */
3523 +    public <U> U reduce(long parallelismThreshold,
3524 +                        BiFun<? super K, ? super V, ? extends U> transformer,
3525 +                        BiFun<? super U, ? super U, ? extends U> reducer) {
3526 +        if (transformer == null || reducer == null)
3527 +            throw new NullPointerException();
3528 +        return new MapReduceMappingsTask<K,V,U>
3529 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3530 +             null, transformer, reducer).invoke();
3531 +    }
3532 +
3533 +    /**
3534 +     * Returns the result of accumulating the given transformation
3535 +     * of all (key, value) pairs using the given reducer to
3536 +     * combine values, and the given basis as an identity value.
3537 +     *
3538 +     * @param parallelismThreshold the (estimated) number of elements
3539 +     * needed for this operation to be executed in parallel
3540 +     * @param transformer a function returning the transformation
3541 +     * for an element
3542 +     * @param basis the identity (initial default value) for the reduction
3543 +     * @param reducer a commutative associative combining function
3544 +     * @return the result of accumulating the given transformation
3545 +     * of all (key, value) pairs
3546 +     * @since 1.8
3547 +     */
3548 +    public double reduceToDouble(long parallelismThreshold,
3549 +                                 ObjectByObjectToDouble<? super K, ? super V> transformer,
3550 +                                 double basis,
3551 +                                 DoubleByDoubleToDouble reducer) {
3552 +        if (transformer == null || reducer == null)
3553 +            throw new NullPointerException();
3554 +        return new MapReduceMappingsToDoubleTask<K,V>
3555 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3556 +             null, transformer, basis, reducer).invoke();
3557 +    }
3558 +
3559 +    /**
3560 +     * Returns the result of accumulating the given transformation
3561 +     * of all (key, value) pairs using the given reducer to
3562 +     * combine values, and the given basis as an identity value.
3563 +     *
3564 +     * @param parallelismThreshold the (estimated) number of elements
3565 +     * needed for this operation to be executed in parallel
3566 +     * @param transformer a function returning the transformation
3567 +     * for an element
3568 +     * @param basis the identity (initial default value) for the reduction
3569 +     * @param reducer a commutative associative combining function
3570 +     * @return the result of accumulating the given transformation
3571 +     * of all (key, value) pairs
3572 +     * @since 1.8
3573 +     */
3574 +    public long reduceToLong(long parallelismThreshold,
3575 +                             ObjectByObjectToLong<? super K, ? super V> transformer,
3576 +                             long basis,
3577 +                             LongByLongToLong reducer) {
3578 +        if (transformer == null || reducer == null)
3579 +            throw new NullPointerException();
3580 +        return new MapReduceMappingsToLongTask<K,V>
3581 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3582 +             null, transformer, basis, reducer).invoke();
3583 +    }
3584 +
3585 +    /**
3586 +     * Returns the result of accumulating the given transformation
3587 +     * of all (key, value) pairs using the given reducer to
3588 +     * combine values, and the given basis as an identity value.
3589 +     *
3590 +     * @param parallelismThreshold the (estimated) number of elements
3591 +     * needed for this operation to be executed in parallel
3592 +     * @param transformer a function returning the transformation
3593 +     * for an element
3594 +     * @param basis the identity (initial default value) for the reduction
3595 +     * @param reducer a commutative associative combining function
3596 +     * @return the result of accumulating the given transformation
3597 +     * of all (key, value) pairs
3598 +     * @since 1.8
3599 +     */
3600 +    public int reduceToInt(long parallelismThreshold,
3601 +                           ObjectByObjectToInt<? super K, ? super V> transformer,
3602 +                           int basis,
3603 +                           IntByIntToInt reducer) {
3604 +        if (transformer == null || reducer == null)
3605 +            throw new NullPointerException();
3606 +        return new MapReduceMappingsToIntTask<K,V>
3607 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3608 +             null, transformer, basis, reducer).invoke();
3609 +    }
3610 +
3611 +    /**
3612 +     * Performs the given action for each key.
3613 +     *
3614 +     * @param parallelismThreshold the (estimated) number of elements
3615 +     * needed for this operation to be executed in parallel
3616 +     * @param action the action
3617 +     * @since 1.8
3618 +     */
3619 +    public void forEachKey(long parallelismThreshold,
3620 +                           Action<? super K> action) {
3621 +        if (action == null) throw new NullPointerException();
3622 +        new ForEachKeyTask<K,V>
3623 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3624 +             action).invoke();
3625 +    }
3626 +
3627 +    /**
3628 +     * Performs the given action for each non-null transformation
3629 +     * of each key.
3630 +     *
3631 +     * @param parallelismThreshold the (estimated) number of elements
3632 +     * needed for this operation to be executed in parallel
3633 +     * @param transformer a function returning the transformation
3634 +     * for an element, or null if there is no transformation (in
3635 +     * which case the action is not applied)
3636 +     * @param action the action
3637 +     * @since 1.8
3638 +     */
3639 +    public <U> void forEachKey(long parallelismThreshold,
3640 +                               Fun<? super K, ? extends U> transformer,
3641 +                               Action<? super U> action) {
3642 +        if (transformer == null || action == null)
3643 +            throw new NullPointerException();
3644 +        new ForEachTransformedKeyTask<K,V,U>
3645 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3646 +             transformer, action).invoke();
3647 +    }
3648 +
3649 +    /**
3650 +     * Returns a non-null result from applying the given search
3651 +     * function on each key, or null if none. Upon success,
3652 +     * further element processing is suppressed and the results of
3653 +     * any other parallel invocations of the search function are
3654 +     * ignored.
3655 +     *
3656 +     * @param parallelismThreshold the (estimated) number of elements
3657 +     * needed for this operation to be executed in parallel
3658 +     * @param searchFunction a function returning a non-null
3659 +     * result on success, else null
3660 +     * @return a non-null result from applying the given search
3661 +     * function on each key, or null if none
3662 +     * @since 1.8
3663 +     */
3664 +    public <U> U searchKeys(long parallelismThreshold,
3665 +                            Fun<? super K, ? extends U> searchFunction) {
3666 +        if (searchFunction == null) throw new NullPointerException();
3667 +        return new SearchKeysTask<K,V,U>
3668 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3669 +             searchFunction, new AtomicReference<U>()).invoke();
3670 +    }
3671 +
3672 +    /**
3673 +     * Returns the result of accumulating all keys using the given
3674 +     * reducer to combine values, or null if none.
3675 +     *
3676 +     * @param parallelismThreshold the (estimated) number of elements
3677 +     * needed for this operation to be executed in parallel
3678 +     * @param reducer a commutative associative combining function
3679 +     * @return the result of accumulating all keys using the given
3680 +     * reducer to combine values, or null if none
3681 +     * @since 1.8
3682 +     */
3683 +    public K reduceKeys(long parallelismThreshold,
3684 +                        BiFun<? super K, ? super K, ? extends K> reducer) {
3685 +        if (reducer == null) throw new NullPointerException();
3686 +        return new ReduceKeysTask<K,V>
3687 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3688 +             null, reducer).invoke();
3689 +    }
3690 +
3691 +    /**
3692 +     * Returns the result of accumulating the given transformation
3693 +     * of all keys using the given reducer to combine values, or
3694 +     * null if none.
3695 +     *
3696 +     * @param parallelismThreshold the (estimated) number of elements
3697 +     * needed for this operation to be executed in parallel
3698 +     * @param transformer a function returning the transformation
3699 +     * for an element, or null if there is no transformation (in
3700 +     * which case it is not combined)
3701 +     * @param reducer a commutative associative combining function
3702 +     * @return the result of accumulating the given transformation
3703 +     * of all keys
3704 +     * @since 1.8
3705 +     */
3706 +    public <U> U reduceKeys(long parallelismThreshold,
3707 +                            Fun<? super K, ? extends U> transformer,
3708 +         BiFun<? super U, ? super U, ? extends U> reducer) {
3709 +        if (transformer == null || reducer == null)
3710 +            throw new NullPointerException();
3711 +        return new MapReduceKeysTask<K,V,U>
3712 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3713 +             null, transformer, reducer).invoke();
3714 +    }
3715 +
3716 +    /**
3717 +     * Returns the result of accumulating the given transformation
3718 +     * of all keys using the given reducer to combine values, and
3719 +     * the given basis as an identity value.
3720 +     *
3721 +     * @param parallelismThreshold the (estimated) number of elements
3722 +     * needed for this operation to be executed in parallel
3723 +     * @param transformer a function returning the transformation
3724 +     * for an element
3725 +     * @param basis the identity (initial default value) for the reduction
3726 +     * @param reducer a commutative associative combining function
3727 +     * @return the result of accumulating the given transformation
3728 +     * of all keys
3729 +     * @since 1.8
3730 +     */
3731 +    public double reduceKeysToDouble(long parallelismThreshold,
3732 +                                     ObjectToDouble<? super K> transformer,
3733 +                                     double basis,
3734 +                                     DoubleByDoubleToDouble reducer) {
3735 +        if (transformer == null || reducer == null)
3736 +            throw new NullPointerException();
3737 +        return new MapReduceKeysToDoubleTask<K,V>
3738 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3739 +             null, transformer, basis, reducer).invoke();
3740 +    }
3741 +
3742 +    /**
3743 +     * Returns the result of accumulating the given transformation
3744 +     * of all keys using the given reducer to combine values, and
3745 +     * the given basis as an identity value.
3746 +     *
3747 +     * @param parallelismThreshold the (estimated) number of elements
3748 +     * needed for this operation to be executed in parallel
3749 +     * @param transformer a function returning the transformation
3750 +     * for an element
3751 +     * @param basis the identity (initial default value) for the reduction
3752 +     * @param reducer a commutative associative combining function
3753 +     * @return the result of accumulating the given transformation
3754 +     * of all keys
3755 +     * @since 1.8
3756 +     */
3757 +    public long reduceKeysToLong(long parallelismThreshold,
3758 +                                 ObjectToLong<? super K> transformer,
3759 +                                 long basis,
3760 +                                 LongByLongToLong reducer) {
3761 +        if (transformer == null || reducer == null)
3762 +            throw new NullPointerException();
3763 +        return new MapReduceKeysToLongTask<K,V>
3764 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3765 +             null, transformer, basis, reducer).invoke();
3766 +    }
3767 +
3768 +    /**
3769 +     * Returns the result of accumulating the given transformation
3770 +     * of all keys using the given reducer to combine values, and
3771 +     * the given basis as an identity value.
3772 +     *
3773 +     * @param parallelismThreshold the (estimated) number of elements
3774 +     * needed for this operation to be executed in parallel
3775 +     * @param transformer a function returning the transformation
3776 +     * for an element
3777 +     * @param basis the identity (initial default value) for the reduction
3778 +     * @param reducer a commutative associative combining function
3779 +     * @return the result of accumulating the given transformation
3780 +     * of all keys
3781 +     * @since 1.8
3782 +     */
3783 +    public int reduceKeysToInt(long parallelismThreshold,
3784 +                               ObjectToInt<? super K> transformer,
3785 +                               int basis,
3786 +                               IntByIntToInt reducer) {
3787 +        if (transformer == null || reducer == null)
3788 +            throw new NullPointerException();
3789 +        return new MapReduceKeysToIntTask<K,V>
3790 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3791 +             null, transformer, basis, reducer).invoke();
3792 +    }
3793 +
3794 +    /**
3795 +     * Performs the given action for each value.
3796 +     *
3797 +     * @param parallelismThreshold the (estimated) number of elements
3798 +     * needed for this operation to be executed in parallel
3799 +     * @param action the action
3800 +     * @since 1.8
3801 +     */
3802 +    public void forEachValue(long parallelismThreshold,
3803 +                             Action<? super V> action) {
3804 +        if (action == null)
3805 +            throw new NullPointerException();
3806 +        new ForEachValueTask<K,V>
3807 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3808 +             action).invoke();
3809 +    }
3810 +
3811 +    /**
3812 +     * Performs the given action for each non-null transformation
3813 +     * of each value.
3814 +     *
3815 +     * @param parallelismThreshold the (estimated) number of elements
3816 +     * needed for this operation to be executed in parallel
3817 +     * @param transformer a function returning the transformation
3818 +     * for an element, or null if there is no transformation (in
3819 +     * which case the action is not applied)
3820 +     * @param action the action
3821 +     * @since 1.8
3822 +     */
3823 +    public <U> void forEachValue(long parallelismThreshold,
3824 +                                 Fun<? super V, ? extends U> transformer,
3825 +                                 Action<? super U> action) {
3826 +        if (transformer == null || action == null)
3827 +            throw new NullPointerException();
3828 +        new ForEachTransformedValueTask<K,V,U>
3829 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3830 +             transformer, action).invoke();
3831 +    }
3832 +
3833 +    /**
3834 +     * Returns a non-null result from applying the given search
3835 +     * function on each value, or null if none.  Upon success,
3836 +     * further element processing is suppressed and the results of
3837 +     * any other parallel invocations of the search function are
3838 +     * ignored.
3839 +     *
3840 +     * @param parallelismThreshold the (estimated) number of elements
3841 +     * needed for this operation to be executed in parallel
3842 +     * @param searchFunction a function returning a non-null
3843 +     * result on success, else null
3844 +     * @return a non-null result from applying the given search
3845 +     * function on each value, or null if none
3846 +     * @since 1.8
3847 +     */
3848 +    public <U> U searchValues(long parallelismThreshold,
3849 +                              Fun<? super V, ? extends U> searchFunction) {
3850 +        if (searchFunction == null) throw new NullPointerException();
3851 +        return new SearchValuesTask<K,V,U>
3852 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3853 +             searchFunction, new AtomicReference<U>()).invoke();
3854 +    }
3855 +
3856 +    /**
3857 +     * Returns the result of accumulating all values using the
3858 +     * given reducer to combine values, or null if none.
3859 +     *
3860 +     * @param parallelismThreshold the (estimated) number of elements
3861 +     * needed for this operation to be executed in parallel
3862 +     * @param reducer a commutative associative combining function
3863 +     * @return the result of accumulating all values
3864 +     * @since 1.8
3865 +     */
3866 +    public V reduceValues(long parallelismThreshold,
3867 +                          BiFun<? super V, ? super V, ? extends V> reducer) {
3868 +        if (reducer == null) throw new NullPointerException();
3869 +        return new ReduceValuesTask<K,V>
3870 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3871 +             null, reducer).invoke();
3872 +    }
3873 +
3874 +    /**
3875 +     * Returns the result of accumulating the given transformation
3876 +     * of all values using the given reducer to combine values, or
3877 +     * null if none.
3878 +     *
3879 +     * @param parallelismThreshold the (estimated) number of elements
3880 +     * needed for this operation to be executed in parallel
3881 +     * @param transformer a function returning the transformation
3882 +     * for an element, or null if there is no transformation (in
3883 +     * which case it is not combined)
3884 +     * @param reducer a commutative associative combining function
3885 +     * @return the result of accumulating the given transformation
3886 +     * of all values
3887 +     * @since 1.8
3888 +     */
3889 +    public <U> U reduceValues(long parallelismThreshold,
3890 +                              Fun<? super V, ? extends U> transformer,
3891 +                              BiFun<? super U, ? super U, ? extends U> reducer) {
3892 +        if (transformer == null || reducer == null)
3893 +            throw new NullPointerException();
3894 +        return new MapReduceValuesTask<K,V,U>
3895 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3896 +             null, transformer, reducer).invoke();
3897 +    }
3898 +
3899 +    /**
3900 +     * Returns the result of accumulating the given transformation
3901 +     * of all values using the given reducer to combine values,
3902 +     * and the given basis as an identity value.
3903 +     *
3904 +     * @param parallelismThreshold the (estimated) number of elements
3905 +     * needed for this operation to be executed in parallel
3906 +     * @param transformer a function returning the transformation
3907 +     * for an element
3908 +     * @param basis the identity (initial default value) for the reduction
3909 +     * @param reducer a commutative associative combining function
3910 +     * @return the result of accumulating the given transformation
3911 +     * of all values
3912 +     * @since 1.8
3913 +     */
3914 +    public double reduceValuesToDouble(long parallelismThreshold,
3915 +                                       ObjectToDouble<? super V> transformer,
3916 +                                       double basis,
3917 +                                       DoubleByDoubleToDouble reducer) {
3918 +        if (transformer == null || reducer == null)
3919 +            throw new NullPointerException();
3920 +        return new MapReduceValuesToDoubleTask<K,V>
3921 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3922 +             null, transformer, basis, reducer).invoke();
3923 +    }
3924 +
3925 +    /**
3926 +     * Returns the result of accumulating the given transformation
3927 +     * of all values using the given reducer to combine values,
3928 +     * and the given basis as an identity value.
3929 +     *
3930 +     * @param parallelismThreshold the (estimated) number of elements
3931 +     * needed for this operation to be executed in parallel
3932 +     * @param transformer a function returning the transformation
3933 +     * for an element
3934 +     * @param basis the identity (initial default value) for the reduction
3935 +     * @param reducer a commutative associative combining function
3936 +     * @return the result of accumulating the given transformation
3937 +     * of all values
3938 +     * @since 1.8
3939 +     */
3940 +    public long reduceValuesToLong(long parallelismThreshold,
3941 +                                   ObjectToLong<? super V> transformer,
3942 +                                   long basis,
3943 +                                   LongByLongToLong reducer) {
3944 +        if (transformer == null || reducer == null)
3945 +            throw new NullPointerException();
3946 +        return new MapReduceValuesToLongTask<K,V>
3947 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3948 +             null, transformer, basis, reducer).invoke();
3949 +    }
3950 +
3951 +    /**
3952 +     * Returns the result of accumulating the given transformation
3953 +     * of all values using the given reducer to combine values,
3954 +     * and the given basis as an identity value.
3955 +     *
3956 +     * @param parallelismThreshold the (estimated) number of elements
3957 +     * needed for this operation to be executed in parallel
3958 +     * @param transformer a function returning the transformation
3959 +     * for an element
3960 +     * @param basis the identity (initial default value) for the reduction
3961 +     * @param reducer a commutative associative combining function
3962 +     * @return the result of accumulating the given transformation
3963 +     * of all values
3964 +     * @since 1.8
3965 +     */
3966 +    public int reduceValuesToInt(long parallelismThreshold,
3967 +                                 ObjectToInt<? super V> transformer,
3968 +                                 int basis,
3969 +                                 IntByIntToInt reducer) {
3970 +        if (transformer == null || reducer == null)
3971 +            throw new NullPointerException();
3972 +        return new MapReduceValuesToIntTask<K,V>
3973 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3974 +             null, transformer, basis, reducer).invoke();
3975 +    }
3976 +
3977 +    /**
3978 +     * Performs the given action for each entry.
3979 +     *
3980 +     * @param parallelismThreshold the (estimated) number of elements
3981 +     * needed for this operation to be executed in parallel
3982 +     * @param action the action
3983 +     * @since 1.8
3984 +     */
3985 +    public void forEachEntry(long parallelismThreshold,
3986 +                             Action<? super Map.Entry<K,V>> action) {
3987 +        if (action == null) throw new NullPointerException();
3988 +        new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
3989 +                                  action).invoke();
3990 +    }
3991 +
3992 +    /**
3993 +     * Performs the given action for each non-null transformation
3994 +     * of each entry.
3995 +     *
3996 +     * @param parallelismThreshold the (estimated) number of elements
3997 +     * needed for this operation to be executed in parallel
3998 +     * @param transformer a function returning the transformation
3999 +     * for an element, or null if there is no transformation (in
4000 +     * which case the action is not applied)
4001 +     * @param action the action
4002 +     * @since 1.8
4003 +     */
4004 +    public <U> void forEachEntry(long parallelismThreshold,
4005 +                                 Fun<Map.Entry<K,V>, ? extends U> transformer,
4006 +                                 Action<? super U> action) {
4007 +        if (transformer == null || action == null)
4008 +            throw new NullPointerException();
4009 +        new ForEachTransformedEntryTask<K,V,U>
4010 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4011 +             transformer, action).invoke();
4012 +    }
4013 +
4014 +    /**
4015 +     * Returns a non-null result from applying the given search
4016 +     * function on each entry, or null if none.  Upon success,
4017 +     * further element processing is suppressed and the results of
4018 +     * any other parallel invocations of the search function are
4019 +     * ignored.
4020 +     *
4021 +     * @param parallelismThreshold the (estimated) number of elements
4022 +     * needed for this operation to be executed in parallel
4023 +     * @param searchFunction a function returning a non-null
4024 +     * result on success, else null
4025 +     * @return a non-null result from applying the given search
4026 +     * function on each entry, or null if none
4027 +     * @since 1.8
4028 +     */
4029 +    public <U> U searchEntries(long parallelismThreshold,
4030 +                               Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4031 +        if (searchFunction == null) throw new NullPointerException();
4032 +        return new SearchEntriesTask<K,V,U>
4033 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4034 +             searchFunction, new AtomicReference<U>()).invoke();
4035 +    }
4036 +
4037 +    /**
4038 +     * Returns the result of accumulating all entries using the
4039 +     * given reducer to combine values, or null if none.
4040 +     *
4041 +     * @param parallelismThreshold the (estimated) number of elements
4042 +     * needed for this operation to be executed in parallel
4043 +     * @param reducer a commutative associative combining function
4044 +     * @return the result of accumulating all entries
4045 +     * @since 1.8
4046 +     */
4047 +    public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4048 +                                        BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4049 +        if (reducer == null) throw new NullPointerException();
4050 +        return new ReduceEntriesTask<K,V>
4051 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4052 +             null, reducer).invoke();
4053 +    }
4054 +
4055 +    /**
4056 +     * Returns the result of accumulating the given transformation
4057 +     * of all entries using the given reducer to combine values,
4058 +     * or null if none.
4059 +     *
4060 +     * @param parallelismThreshold the (estimated) number of elements
4061 +     * needed for this operation to be executed in parallel
4062 +     * @param transformer a function returning the transformation
4063 +     * for an element, or null if there is no transformation (in
4064 +     * which case it is not combined)
4065 +     * @param reducer a commutative associative combining function
4066 +     * @return the result of accumulating the given transformation
4067 +     * of all entries
4068 +     * @since 1.8
4069 +     */
4070 +    public <U> U reduceEntries(long parallelismThreshold,
4071 +                               Fun<Map.Entry<K,V>, ? extends U> transformer,
4072 +                               BiFun<? super U, ? super U, ? extends U> reducer) {
4073 +        if (transformer == null || reducer == null)
4074 +            throw new NullPointerException();
4075 +        return new MapReduceEntriesTask<K,V,U>
4076 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4077 +             null, transformer, reducer).invoke();
4078 +    }
4079 +
4080 +    /**
4081 +     * Returns the result of accumulating the given transformation
4082 +     * of all entries using the given reducer to combine values,
4083 +     * and the given basis as an identity value.
4084 +     *
4085 +     * @param parallelismThreshold the (estimated) number of elements
4086 +     * needed for this operation to be executed in parallel
4087 +     * @param transformer a function returning the transformation
4088 +     * for an element
4089 +     * @param basis the identity (initial default value) for the reduction
4090 +     * @param reducer a commutative associative combining function
4091 +     * @return the result of accumulating the given transformation
4092 +     * of all entries
4093 +     * @since 1.8
4094 +     */
4095 +    public double reduceEntriesToDouble(long parallelismThreshold,
4096 +                                        ObjectToDouble<Map.Entry<K,V>> transformer,
4097 +                                        double basis,
4098 +                                        DoubleByDoubleToDouble reducer) {
4099 +        if (transformer == null || reducer == null)
4100 +            throw new NullPointerException();
4101 +        return new MapReduceEntriesToDoubleTask<K,V>
4102 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4103 +             null, transformer, basis, reducer).invoke();
4104 +    }
4105 +
4106 +    /**
4107 +     * Returns the result of accumulating the given transformation
4108 +     * of all entries using the given reducer to combine values,
4109 +     * and the given basis as an identity value.
4110 +     *
4111 +     * @param parallelismThreshold the (estimated) number of elements
4112 +     * needed for this operation to be executed in parallel
4113 +     * @param transformer a function returning the transformation
4114 +     * for an element
4115 +     * @param basis the identity (initial default value) for the reduction
4116 +     * @param reducer a commutative associative combining function
4117 +     * @return the result of accumulating the given transformation
4118 +     * of all entries
4119 +     * @since 1.8
4120 +     */
4121 +    public long reduceEntriesToLong(long parallelismThreshold,
4122 +                                    ObjectToLong<Map.Entry<K,V>> transformer,
4123 +                                    long basis,
4124 +                                    LongByLongToLong reducer) {
4125 +        if (transformer == null || reducer == null)
4126 +            throw new NullPointerException();
4127 +        return new MapReduceEntriesToLongTask<K,V>
4128 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4129 +             null, transformer, basis, reducer).invoke();
4130 +    }
4131 +
4132 +    /**
4133 +     * Returns the result of accumulating the given transformation
4134 +     * of all entries using the given reducer to combine values,
4135 +     * and the given basis as an identity value.
4136 +     *
4137 +     * @param parallelismThreshold the (estimated) number of elements
4138 +     * needed for this operation to be executed in parallel
4139 +     * @param transformer a function returning the transformation
4140 +     * for an element
4141 +     * @param basis the identity (initial default value) for the reduction
4142 +     * @param reducer a commutative associative combining function
4143 +     * @return the result of accumulating the given transformation
4144 +     * of all entries
4145 +     * @since 1.8
4146 +     */
4147 +    public int reduceEntriesToInt(long parallelismThreshold,
4148 +                                  ObjectToInt<Map.Entry<K,V>> transformer,
4149 +                                  int basis,
4150 +                                  IntByIntToInt reducer) {
4151 +        if (transformer == null || reducer == null)
4152 +            throw new NullPointerException();
4153 +        return new MapReduceEntriesToIntTask<K,V>
4154 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4155 +             null, transformer, basis, reducer).invoke();
4156 +    }
4157 +
4158 +
4159 +    /* ----------------Views -------------- */
4160 +
4161 +    /**
4162 +     * Base class for views.
4163 +     */
4164 +    abstract static class CollectionView<K,V,E>
4165 +        implements Collection<E>, java.io.Serializable {
4166 +        private static final long serialVersionUID = 7249069246763182397L;
4167 +        final ConcurrentHashMapV8<K,V> map;
4168 +        CollectionView(ConcurrentHashMapV8<K,V> map)  { this.map = map; }
4169 +
4170          /**
4171 <         * Returns a task that when invoked, returns the result of
4279 <         * accumulating the given transformation of all (key, value) pairs
4280 <         * using the given reducer to combine values, and the given
4281 <         * basis as an identity value.
4171 >         * Returns the map backing this view.
4172           *
4173 <         * @param transformer a function returning the transformation
4284 <         * for an element
4285 <         * @param basis the identity (initial default value) for the reduction
4286 <         * @param reducer a commutative associative combining function
4287 <         * @return the task
4173 >         * @return the map backing this view
4174           */
4175 <        public static <K,V> ForkJoinTask<Integer> reduceToInt
4290 <            (ConcurrentHashMapV8<K,V> map,
4291 <             ObjectByObjectToInt<? super K, ? super V> transformer,
4292 <             int basis,
4293 <             IntByIntToInt reducer) {
4294 <            if (transformer == null || reducer == null)
4295 <                throw new NullPointerException();
4296 <            return new MapReduceMappingsToIntTask<K,V>
4297 <                (map, transformer, basis, reducer);
4298 <        }
4175 >        public ConcurrentHashMapV8<K,V> getMap() { return map; }
4176  
4177          /**
4178 <         * Returns a task that when invoked, performs the given action
4179 <         * for each key.
4303 <         *
4304 <         * @param map the map
4305 <         * @param action the action
4306 <         * @return the task
4178 >         * Removes all of the elements from this view, by removing all
4179 >         * the mappings from the map backing this view.
4180           */
4181 <        public static <K,V> ForkJoinTask<Void> forEachKey
4182 <            (ConcurrentHashMapV8<K,V> map,
4183 <             Action<K> action) {
4311 <            if (action == null) throw new NullPointerException();
4312 <            return new ForEachKeyTask<K,V>(map, action);
4313 <        }
4181 >        public final void clear()      { map.clear(); }
4182 >        public final int size()        { return map.size(); }
4183 >        public final boolean isEmpty() { return map.isEmpty(); }
4184  
4185 +        // implementations below rely on concrete classes supplying these
4186 +        // abstract methods
4187          /**
4188 <         * Returns a task that when invoked, performs the given action
4189 <         * for each non-null transformation of each key.
4190 <         *
4191 <         * @param map the map
4192 <         * @param transformer a function returning the transformation
4193 <         * for an element, or null of there is no transformation (in
4194 <         * which case the action is not applied).
4195 <         * @param action the action
4196 <         * @return the task
4197 <         */
4198 <        public static <K,V,U> ForkJoinTask<Void> forEachKey
4199 <            (ConcurrentHashMapV8<K,V> map,
4200 <             Fun<? super K, ? extends U> transformer,
4201 <             Action<U> action) {
4202 <            if (transformer == null || action == null)
4203 <                throw new NullPointerException();
4204 <            return new ForEachTransformedKeyTask<K,V,U>
4205 <                (map, transformer, action);
4188 >         * Returns a "weakly consistent" iterator that will never
4189 >         * throw {@link ConcurrentModificationException}, and
4190 >         * guarantees to traverse elements as they existed upon
4191 >         * construction of the iterator, and may (but is not
4192 >         * guaranteed to) reflect any modifications subsequent to
4193 >         * construction.
4194 >         */
4195 >        public abstract Iterator<E> iterator();
4196 >        public abstract boolean contains(Object o);
4197 >        public abstract boolean remove(Object o);
4198 >
4199 >        private static final String oomeMsg = "Required array size too large";
4200 >
4201 >        public final Object[] toArray() {
4202 >            long sz = map.mappingCount();
4203 >            if (sz > MAX_ARRAY_SIZE)
4204 >                throw new OutOfMemoryError(oomeMsg);
4205 >            int n = (int)sz;
4206 >            Object[] r = new Object[n];
4207 >            int i = 0;
4208 >            for (E e : this) {
4209 >                if (i == n) {
4210 >                    if (n >= MAX_ARRAY_SIZE)
4211 >                        throw new OutOfMemoryError(oomeMsg);
4212 >                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4213 >                        n = MAX_ARRAY_SIZE;
4214 >                    else
4215 >                        n += (n >>> 1) + 1;
4216 >                    r = Arrays.copyOf(r, n);
4217 >                }
4218 >                r[i++] = e;
4219 >            }
4220 >            return (i == n) ? r : Arrays.copyOf(r, i);
4221          }
4222  
4223 <        /**
4224 <         * Returns a task that when invoked, returns a non-null result
4225 <         * from applying the given search function on each key, or
4226 <         * null if none.  Upon success, further element processing is
4227 <         * suppressed and the results of any other parallel
4228 <         * invocations of the search function are ignored.
4229 <         *
4230 <         * @param map the map
4231 <         * @param searchFunction a function returning a non-null
4232 <         * result on success, else null
4233 <         * @return the task
4234 <         */
4235 <        public static <K,V,U> ForkJoinTask<U> searchKeys
4236 <            (ConcurrentHashMapV8<K,V> map,
4237 <             Fun<? super K, ? extends U> searchFunction) {
4238 <            if (searchFunction == null) throw new NullPointerException();
4239 <            return new SearchKeysTask<K,V,U>
4240 <                (map, searchFunction,
4241 <                 new AtomicReference<U>());
4223 >        @SuppressWarnings("unchecked")
4224 >        public final <T> T[] toArray(T[] a) {
4225 >            long sz = map.mappingCount();
4226 >            if (sz > MAX_ARRAY_SIZE)
4227 >                throw new OutOfMemoryError(oomeMsg);
4228 >            int m = (int)sz;
4229 >            T[] r = (a.length >= m) ? a :
4230 >                (T[])java.lang.reflect.Array
4231 >                .newInstance(a.getClass().getComponentType(), m);
4232 >            int n = r.length;
4233 >            int i = 0;
4234 >            for (E e : this) {
4235 >                if (i == n) {
4236 >                    if (n >= MAX_ARRAY_SIZE)
4237 >                        throw new OutOfMemoryError(oomeMsg);
4238 >                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4239 >                        n = MAX_ARRAY_SIZE;
4240 >                    else
4241 >                        n += (n >>> 1) + 1;
4242 >                    r = Arrays.copyOf(r, n);
4243 >                }
4244 >                r[i++] = (T)e;
4245 >            }
4246 >            if (a == r && i < n) {
4247 >                r[i] = null; // null-terminate
4248 >                return r;
4249 >            }
4250 >            return (i == n) ? r : Arrays.copyOf(r, i);
4251          }
4252  
4253          /**
4254 <         * Returns a task that when invoked, returns the result of
4255 <         * accumulating all keys using the given reducer to combine
4256 <         * values, or null if none.
4254 >         * Returns a string representation of this collection.
4255 >         * The string representation consists of the string representations
4256 >         * of the collection's elements in the order they are returned by
4257 >         * its iterator, enclosed in square brackets ({@code "[]"}).
4258 >         * Adjacent elements are separated by the characters {@code ", "}
4259 >         * (comma and space).  Elements are converted to strings as by
4260 >         * {@link String#valueOf(Object)}.
4261           *
4262 <         * @param map the map
4363 <         * @param reducer a commutative associative combining function
4364 <         * @return the task
4262 >         * @return a string representation of this collection
4263           */
4264 <        public static <K,V> ForkJoinTask<K> reduceKeys
4265 <            (ConcurrentHashMapV8<K,V> map,
4266 <             BiFun<? super K, ? super K, ? extends K> reducer) {
4267 <            if (reducer == null) throw new NullPointerException();
4268 <            return new ReduceKeysTask<K,V>
4269 <                (map, reducer);
4264 >        public final String toString() {
4265 >            StringBuilder sb = new StringBuilder();
4266 >            sb.append('[');
4267 >            Iterator<E> it = iterator();
4268 >            if (it.hasNext()) {
4269 >                for (;;) {
4270 >                    Object e = it.next();
4271 >                    sb.append(e == this ? "(this Collection)" : e);
4272 >                    if (!it.hasNext())
4273 >                        break;
4274 >                    sb.append(',').append(' ');
4275 >                }
4276 >            }
4277 >            return sb.append(']').toString();
4278          }
4279  
4280 <        /**
4281 <         * Returns a task that when invoked, returns the result of
4282 <         * accumulating the given transformation of all keys using the given
4283 <         * reducer to combine values, or null if none.
4284 <         *
4285 <         * @param map the map
4286 <         * @param transformer a function returning the transformation
4287 <         * for an element, or null of there is no transformation (in
4382 <         * which case it is not combined).
4383 <         * @param reducer a commutative associative combining function
4384 <         * @return the task
4385 <         */
4386 <        public static <K,V,U> ForkJoinTask<U> reduceKeys
4387 <            (ConcurrentHashMapV8<K,V> map,
4388 <             Fun<? super K, ? extends U> transformer,
4389 <             BiFun<? super U, ? super U, ? extends U> reducer) {
4390 <            if (transformer == null || reducer == null)
4391 <                throw new NullPointerException();
4392 <            return new MapReduceKeysTask<K,V,U>
4393 <                (map, transformer, reducer);
4280 >        public final boolean containsAll(Collection<?> c) {
4281 >            if (c != this) {
4282 >                for (Object e : c) {
4283 >                    if (e == null || !contains(e))
4284 >                        return false;
4285 >                }
4286 >            }
4287 >            return true;
4288          }
4289  
4290 <        /**
4291 <         * Returns a task that when invoked, returns the result of
4292 <         * accumulating the given transformation of all keys using the given
4293 <         * reducer to combine values, and the given basis as an
4294 <         * identity value.
4295 <         *
4296 <         * @param map the map
4297 <         * @param transformer a function returning the transformation
4298 <         * for an element
4405 <         * @param basis the identity (initial default value) for the reduction
4406 <         * @param reducer a commutative associative combining function
4407 <         * @return the task
4408 <         */
4409 <        public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
4410 <            (ConcurrentHashMapV8<K,V> map,
4411 <             ObjectToDouble<? super K> transformer,
4412 <             double basis,
4413 <             DoubleByDoubleToDouble reducer) {
4414 <            if (transformer == null || reducer == null)
4415 <                throw new NullPointerException();
4416 <            return new MapReduceKeysToDoubleTask<K,V>
4417 <                (map, transformer, basis, reducer);
4290 >        public final boolean removeAll(Collection<?> c) {
4291 >            boolean modified = false;
4292 >            for (Iterator<E> it = iterator(); it.hasNext();) {
4293 >                if (c.contains(it.next())) {
4294 >                    it.remove();
4295 >                    modified = true;
4296 >                }
4297 >            }
4298 >            return modified;
4299          }
4300  
4301 <        /**
4302 <         * Returns a task that when invoked, returns the result of
4303 <         * accumulating the given transformation of all keys using the given
4304 <         * reducer to combine values, and the given basis as an
4305 <         * identity value.
4306 <         *
4307 <         * @param map the map
4308 <         * @param transformer a function returning the transformation
4309 <         * for an element
4429 <         * @param basis the identity (initial default value) for the reduction
4430 <         * @param reducer a commutative associative combining function
4431 <         * @return the task
4432 <         */
4433 <        public static <K,V> ForkJoinTask<Long> reduceKeysToLong
4434 <            (ConcurrentHashMapV8<K,V> map,
4435 <             ObjectToLong<? super K> transformer,
4436 <             long basis,
4437 <             LongByLongToLong reducer) {
4438 <            if (transformer == null || reducer == null)
4439 <                throw new NullPointerException();
4440 <            return new MapReduceKeysToLongTask<K,V>
4441 <                (map, transformer, basis, reducer);
4301 >        public final boolean retainAll(Collection<?> c) {
4302 >            boolean modified = false;
4303 >            for (Iterator<E> it = iterator(); it.hasNext();) {
4304 >                if (!c.contains(it.next())) {
4305 >                    it.remove();
4306 >                    modified = true;
4307 >                }
4308 >            }
4309 >            return modified;
4310          }
4311  
4312 <        /**
4313 <         * Returns a task that when invoked, returns the result of
4314 <         * accumulating the given transformation of all keys using the given
4315 <         * reducer to combine values, and the given basis as an
4316 <         * identity value.
4317 <         *
4318 <         * @param map the map
4319 <         * @param transformer a function returning the transformation
4320 <         * for an element
4321 <         * @param basis the identity (initial default value) for the reduction
4322 <         * @param reducer a commutative associative combining function
4323 <         * @return the task
4324 <         */
4325 <        public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
4326 <            (ConcurrentHashMapV8<K,V> map,
4327 <             ObjectToInt<? super K> transformer,
4328 <             int basis,
4329 <             IntByIntToInt reducer) {
4330 <            if (transformer == null || reducer == null)
4331 <                throw new NullPointerException();
4464 <            return new MapReduceKeysToIntTask<K,V>
4465 <                (map, transformer, basis, reducer);
4312 >    }
4313 >
4314 >    /**
4315 >     * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in
4316 >     * which additions may optionally be enabled by mapping to a
4317 >     * common value.  This class cannot be directly instantiated.
4318 >     * See {@link #keySet() keySet()},
4319 >     * {@link #keySet(Object) keySet(V)},
4320 >     * {@link #newKeySet() newKeySet()},
4321 >     * {@link #newKeySet(int) newKeySet(int)}.
4322 >     *
4323 >     * @since 1.8
4324 >     */
4325 >    public static class KeySetView<K,V> extends CollectionView<K,V,K>
4326 >        implements Set<K>, java.io.Serializable {
4327 >        private static final long serialVersionUID = 7249069246763182397L;
4328 >        private final V value;
4329 >        KeySetView(ConcurrentHashMapV8<K,V> map, V value) {  // non-public
4330 >            super(map);
4331 >            this.value = value;
4332          }
4333  
4334          /**
4335 <         * Returns a task that when invoked, performs the given action
4336 <         * for each value.
4335 >         * Returns the default mapped value for additions,
4336 >         * or {@code null} if additions are not supported.
4337           *
4338 <         * @param map the map
4339 <         * @param action the action
4338 >         * @return the default mapped value for additions, or {@code null}
4339 >         * if not supported
4340           */
4341 <        public static <K,V> ForkJoinTask<Void> forEachValue
4476 <            (ConcurrentHashMapV8<K,V> map,
4477 <             Action<V> action) {
4478 <            if (action == null) throw new NullPointerException();
4479 <            return new ForEachValueTask<K,V>(map, action);
4480 <        }
4341 >        public V getMappedValue() { return value; }
4342  
4343          /**
4344 <         * Returns a task that when invoked, performs the given action
4345 <         * for each non-null transformation of each value.
4485 <         *
4486 <         * @param map the map
4487 <         * @param transformer a function returning the transformation
4488 <         * for an element, or null of there is no transformation (in
4489 <         * which case the action is not applied).
4490 <         * @param action the action
4344 >         * {@inheritDoc}
4345 >         * @throws NullPointerException if the specified key is null
4346           */
4347 <        public static <K,V,U> ForkJoinTask<Void> forEachValue
4493 <            (ConcurrentHashMapV8<K,V> map,
4494 <             Fun<? super V, ? extends U> transformer,
4495 <             Action<U> action) {
4496 <            if (transformer == null || action == null)
4497 <                throw new NullPointerException();
4498 <            return new ForEachTransformedValueTask<K,V,U>
4499 <                (map, transformer, action);
4500 <        }
4347 >        public boolean contains(Object o) { return map.containsKey(o); }
4348  
4349          /**
4350 <         * Returns a task that when invoked, returns a non-null result
4351 <         * from applying the given search function on each value, or
4352 <         * null if none.  Upon success, further element processing is
4506 <         * suppressed and the results of any other parallel
4507 <         * invocations of the search function are ignored.
4508 <         *
4509 <         * @param map the map
4510 <         * @param searchFunction a function returning a non-null
4511 <         * result on success, else null
4512 <         * @return the task
4350 >         * Removes the key from this map view, by removing the key (and its
4351 >         * corresponding value) from the backing map.  This method does
4352 >         * nothing if the key is not in the map.
4353           *
4354 +         * @param  o the key to be removed from the backing map
4355 +         * @return {@code true} if the backing map contained the specified key
4356 +         * @throws NullPointerException if the specified key is null
4357           */
4358 <        public static <K,V,U> ForkJoinTask<U> searchValues
4516 <            (ConcurrentHashMapV8<K,V> map,
4517 <             Fun<? super V, ? extends U> searchFunction) {
4518 <            if (searchFunction == null) throw new NullPointerException();
4519 <            return new SearchValuesTask<K,V,U>
4520 <                (map, searchFunction,
4521 <                 new AtomicReference<U>());
4522 <        }
4358 >        public boolean remove(Object o) { return map.remove(o) != null; }
4359  
4360          /**
4361 <         * Returns a task that when invoked, returns the result of
4526 <         * accumulating all values using the given reducer to combine
4527 <         * values, or null if none.
4528 <         *
4529 <         * @param map the map
4530 <         * @param reducer a commutative associative combining function
4531 <         * @return the task
4361 >         * @return an iterator over the keys of the backing map
4362           */
4363 <        public static <K,V> ForkJoinTask<V> reduceValues
4364 <            (ConcurrentHashMapV8<K,V> map,
4365 <             BiFun<? super V, ? super V, ? extends V> reducer) {
4366 <            if (reducer == null) throw new NullPointerException();
4367 <            return new ReduceValuesTask<K,V>
4538 <                (map, reducer);
4363 >        public Iterator<K> iterator() {
4364 >            Node<K,V>[] t;
4365 >            ConcurrentHashMapV8<K,V> m = map;
4366 >            int f = (t = m.table) == null ? 0 : t.length;
4367 >            return new KeyIterator<K,V>(t, f, 0, f, m);
4368          }
4369  
4370          /**
4371 <         * Returns a task that when invoked, returns the result of
4372 <         * accumulating the given transformation of all values using the
4544 <         * given reducer to combine values, or null if none.
4371 >         * Adds the specified key to this set view by mapping the key to
4372 >         * the default mapped value in the backing map, if defined.
4373           *
4374 <         * @param map the map
4375 <         * @param transformer a function returning the transformation
4376 <         * for an element, or null of there is no transformation (in
4377 <         * which case it is not combined).
4378 <         * @param reducer a commutative associative combining function
4551 <         * @return the task
4374 >         * @param e key to be added
4375 >         * @return {@code true} if this set changed as a result of the call
4376 >         * @throws NullPointerException if the specified key is null
4377 >         * @throws UnsupportedOperationException if no default mapped value
4378 >         * for additions was provided
4379           */
4380 <        public static <K,V,U> ForkJoinTask<U> reduceValues
4381 <            (ConcurrentHashMapV8<K,V> map,
4382 <             Fun<? super V, ? extends U> transformer,
4383 <             BiFun<? super U, ? super U, ? extends U> reducer) {
4384 <            if (transformer == null || reducer == null)
4558 <                throw new NullPointerException();
4559 <            return new MapReduceValuesTask<K,V,U>
4560 <                (map, transformer, reducer);
4380 >        public boolean add(K e) {
4381 >            V v;
4382 >            if ((v = value) == null)
4383 >                throw new UnsupportedOperationException();
4384 >            return map.putVal(e, v, true) == null;
4385          }
4386  
4387          /**
4388 <         * Returns a task that when invoked, returns the result of
4389 <         * accumulating the given transformation of all values using the
4566 <         * given reducer to combine values, and the given basis as an
4567 <         * identity value.
4388 >         * Adds all of the elements in the specified collection to this set,
4389 >         * as if by calling {@link #add} on each one.
4390           *
4391 <         * @param map the map
4392 <         * @param transformer a function returning the transformation
4393 <         * for an element
4394 <         * @param basis the identity (initial default value) for the reduction
4395 <         * @param reducer a commutative associative combining function
4396 <         * @return the task
4391 >         * @param c the elements to be inserted into this set
4392 >         * @return {@code true} if this set changed as a result of the call
4393 >         * @throws NullPointerException if the collection or any of its
4394 >         * elements are {@code null}
4395 >         * @throws UnsupportedOperationException if no default mapped value
4396 >         * for additions was provided
4397           */
4398 <        public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
4399 <            (ConcurrentHashMapV8<K,V> map,
4400 <             ObjectToDouble<? super V> transformer,
4401 <             double basis,
4402 <             DoubleByDoubleToDouble reducer) {
4403 <            if (transformer == null || reducer == null)
4404 <                throw new NullPointerException();
4405 <            return new MapReduceValuesToDoubleTask<K,V>
4406 <                (map, transformer, basis, reducer);
4398 >        public boolean addAll(Collection<? extends K> c) {
4399 >            boolean added = false;
4400 >            V v;
4401 >            if ((v = value) == null)
4402 >                throw new UnsupportedOperationException();
4403 >            for (K e : c) {
4404 >                if (map.putVal(e, v, true) == null)
4405 >                    added = true;
4406 >            }
4407 >            return added;
4408          }
4409  
4410 <        /**
4411 <         * Returns a task that when invoked, returns the result of
4412 <         * accumulating the given transformation of all values using the
4413 <         * given reducer to combine values, and the given basis as an
4414 <         * identity value.
4592 <         *
4593 <         * @param map the map
4594 <         * @param transformer a function returning the transformation
4595 <         * for an element
4596 <         * @param basis the identity (initial default value) for the reduction
4597 <         * @param reducer a commutative associative combining function
4598 <         * @return the task
4599 <         */
4600 <        public static <K,V> ForkJoinTask<Long> reduceValuesToLong
4601 <            (ConcurrentHashMapV8<K,V> map,
4602 <             ObjectToLong<? super V> transformer,
4603 <             long basis,
4604 <             LongByLongToLong reducer) {
4605 <            if (transformer == null || reducer == null)
4606 <                throw new NullPointerException();
4607 <            return new MapReduceValuesToLongTask<K,V>
4608 <                (map, transformer, basis, reducer);
4410 >        public int hashCode() {
4411 >            int h = 0;
4412 >            for (K e : this)
4413 >                h += e.hashCode();
4414 >            return h;
4415          }
4416  
4417 <        /**
4418 <         * Returns a task that when invoked, returns the result of
4419 <         * accumulating the given transformation of all values using the
4420 <         * given reducer to combine values, and the given basis as an
4421 <         * identity value.
4616 <         *
4617 <         * @param map the map
4618 <         * @param transformer a function returning the transformation
4619 <         * for an element
4620 <         * @param basis the identity (initial default value) for the reduction
4621 <         * @param reducer a commutative associative combining function
4622 <         * @return the task
4623 <         */
4624 <        public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
4625 <            (ConcurrentHashMapV8<K,V> map,
4626 <             ObjectToInt<? super V> transformer,
4627 <             int basis,
4628 <             IntByIntToInt reducer) {
4629 <            if (transformer == null || reducer == null)
4630 <                throw new NullPointerException();
4631 <            return new MapReduceValuesToIntTask<K,V>
4632 <                (map, transformer, basis, reducer);
4417 >        public boolean equals(Object o) {
4418 >            Set<?> c;
4419 >            return ((o instanceof Set) &&
4420 >                    ((c = (Set<?>)o) == this ||
4421 >                     (containsAll(c) && c.containsAll(this))));
4422          }
4423  
4424 <        /**
4425 <         * Returns a task that when invoked, perform the given action
4426 <         * for each entry.
4427 <         *
4428 <         * @param map the map
4429 <         * @param action the action
4641 <         */
4642 <        public static <K,V> ForkJoinTask<Void> forEachEntry
4643 <            (ConcurrentHashMapV8<K,V> map,
4644 <             Action<Map.Entry<K,V>> action) {
4645 <            if (action == null) throw new NullPointerException();
4646 <            return new ForEachEntryTask<K,V>(map, action);
4424 >        public ConcurrentHashMapSpliterator<K> spliterator() {
4425 >            Node<K,V>[] t;
4426 >            ConcurrentHashMapV8<K,V> m = map;
4427 >            long n = m.sumCount();
4428 >            int f = (t = m.table) == null ? 0 : t.length;
4429 >            return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4430          }
4431  
4432 <        /**
4433 <         * Returns a task that when invoked, perform the given action
4434 <         * for each non-null transformation of each entry.
4435 <         *
4436 <         * @param map the map
4437 <         * @param transformer a function returning the transformation
4438 <         * for an element, or null of there is no transformation (in
4439 <         * which case the action is not applied).
4657 <         * @param action the action
4658 <         */
4659 <        public static <K,V,U> ForkJoinTask<Void> forEachEntry
4660 <            (ConcurrentHashMapV8<K,V> map,
4661 <             Fun<Map.Entry<K,V>, ? extends U> transformer,
4662 <             Action<U> action) {
4663 <            if (transformer == null || action == null)
4664 <                throw new NullPointerException();
4665 <            return new ForEachTransformedEntryTask<K,V,U>
4666 <                (map, transformer, action);
4432 >        public void forEach(Action<? super K> action) {
4433 >            if (action == null) throw new NullPointerException();
4434 >            Node<K,V>[] t;
4435 >            if ((t = map.table) != null) {
4436 >                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4437 >                for (Node<K,V> p; (p = it.advance()) != null; )
4438 >                    action.apply(p.key);
4439 >            }
4440          }
4441 +    }
4442  
4443 <        /**
4444 <         * Returns a task that when invoked, returns a non-null result
4445 <         * from applying the given search function on each entry, or
4446 <         * null if none.  Upon success, further element processing is
4447 <         * suppressed and the results of any other parallel
4448 <         * invocations of the search function are ignored.
4449 <         *
4450 <         * @param map the map
4451 <         * @param searchFunction a function returning a non-null
4452 <         * result on success, else null
4453 <         * @return the task
4680 <         *
4681 <         */
4682 <        public static <K,V,U> ForkJoinTask<U> searchEntries
4683 <            (ConcurrentHashMapV8<K,V> map,
4684 <             Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4685 <            if (searchFunction == null) throw new NullPointerException();
4686 <            return new SearchEntriesTask<K,V,U>
4687 <                (map, searchFunction,
4688 <                 new AtomicReference<U>());
4443 >    /**
4444 >     * A view of a ConcurrentHashMapV8 as a {@link Collection} of
4445 >     * values, in which additions are disabled. This class cannot be
4446 >     * directly instantiated. See {@link #values()}.
4447 >     */
4448 >    static final class ValuesView<K,V> extends CollectionView<K,V,V>
4449 >        implements Collection<V>, java.io.Serializable {
4450 >        private static final long serialVersionUID = 2249069246763182397L;
4451 >        ValuesView(ConcurrentHashMapV8<K,V> map) { super(map); }
4452 >        public final boolean contains(Object o) {
4453 >            return map.containsValue(o);
4454          }
4455  
4456 <        /**
4457 <         * Returns a task that when invoked, returns the result of
4458 <         * accumulating all entries using the given reducer to combine
4459 <         * values, or null if none.
4460 <         *
4461 <         * @param map the map
4462 <         * @param reducer a commutative associative combining function
4463 <         * @return the task
4464 <         */
4465 <        public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
4701 <            (ConcurrentHashMapV8<K,V> map,
4702 <             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4703 <            if (reducer == null) throw new NullPointerException();
4704 <            return new ReduceEntriesTask<K,V>
4705 <                (map, reducer);
4456 >        public final boolean remove(Object o) {
4457 >            if (o != null) {
4458 >                for (Iterator<V> it = iterator(); it.hasNext();) {
4459 >                    if (o.equals(it.next())) {
4460 >                        it.remove();
4461 >                        return true;
4462 >                    }
4463 >                }
4464 >            }
4465 >            return false;
4466          }
4467  
4468 <        /**
4469 <         * Returns a task that when invoked, returns the result of
4470 <         * accumulating the given transformation of all entries using the
4471 <         * given reducer to combine values, or null if none.
4472 <         *
4713 <         * @param map the map
4714 <         * @param transformer a function returning the transformation
4715 <         * for an element, or null of there is no transformation (in
4716 <         * which case it is not combined).
4717 <         * @param reducer a commutative associative combining function
4718 <         * @return the task
4719 <         */
4720 <        public static <K,V,U> ForkJoinTask<U> reduceEntries
4721 <            (ConcurrentHashMapV8<K,V> map,
4722 <             Fun<Map.Entry<K,V>, ? extends U> transformer,
4723 <             BiFun<? super U, ? super U, ? extends U> reducer) {
4724 <            if (transformer == null || reducer == null)
4725 <                throw new NullPointerException();
4726 <            return new MapReduceEntriesTask<K,V,U>
4727 <                (map, transformer, reducer);
4468 >        public final Iterator<V> iterator() {
4469 >            ConcurrentHashMapV8<K,V> m = map;
4470 >            Node<K,V>[] t;
4471 >            int f = (t = m.table) == null ? 0 : t.length;
4472 >            return new ValueIterator<K,V>(t, f, 0, f, m);
4473          }
4474  
4475 <        /**
4476 <         * Returns a task that when invoked, returns the result of
4477 <         * accumulating the given transformation of all entries using the
4478 <         * given reducer to combine values, and the given basis as an
4479 <         * identity value.
4735 <         *
4736 <         * @param map the map
4737 <         * @param transformer a function returning the transformation
4738 <         * for an element
4739 <         * @param basis the identity (initial default value) for the reduction
4740 <         * @param reducer a commutative associative combining function
4741 <         * @return the task
4742 <         */
4743 <        public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
4744 <            (ConcurrentHashMapV8<K,V> map,
4745 <             ObjectToDouble<Map.Entry<K,V>> transformer,
4746 <             double basis,
4747 <             DoubleByDoubleToDouble reducer) {
4748 <            if (transformer == null || reducer == null)
4749 <                throw new NullPointerException();
4750 <            return new MapReduceEntriesToDoubleTask<K,V>
4751 <                (map, transformer, basis, reducer);
4475 >        public final boolean add(V e) {
4476 >            throw new UnsupportedOperationException();
4477 >        }
4478 >        public final boolean addAll(Collection<? extends V> c) {
4479 >            throw new UnsupportedOperationException();
4480          }
4481  
4482 <        /**
4483 <         * Returns a task that when invoked, returns the result of
4484 <         * accumulating the given transformation of all entries using the
4485 <         * given reducer to combine values, and the given basis as an
4486 <         * identity value.
4487 <         *
4760 <         * @param map the map
4761 <         * @param transformer a function returning the transformation
4762 <         * for an element
4763 <         * @param basis the identity (initial default value) for the reduction
4764 <         * @param reducer a commutative associative combining function
4765 <         * @return the task
4766 <         */
4767 <        public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
4768 <            (ConcurrentHashMapV8<K,V> map,
4769 <             ObjectToLong<Map.Entry<K,V>> transformer,
4770 <             long basis,
4771 <             LongByLongToLong reducer) {
4772 <            if (transformer == null || reducer == null)
4773 <                throw new NullPointerException();
4774 <            return new MapReduceEntriesToLongTask<K,V>
4775 <                (map, transformer, basis, reducer);
4482 >        public ConcurrentHashMapSpliterator<V> spliterator() {
4483 >            Node<K,V>[] t;
4484 >            ConcurrentHashMapV8<K,V> m = map;
4485 >            long n = m.sumCount();
4486 >            int f = (t = m.table) == null ? 0 : t.length;
4487 >            return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4488          }
4489  
4490 <        /**
4491 <         * Returns a task that when invoked, returns the result of
4492 <         * accumulating the given transformation of all entries using the
4493 <         * given reducer to combine values, and the given basis as an
4494 <         * identity value.
4495 <         *
4496 <         * @param map the map
4497 <         * @param transformer a function returning the transformation
4786 <         * for an element
4787 <         * @param basis the identity (initial default value) for the reduction
4788 <         * @param reducer a commutative associative combining function
4789 <         * @return the task
4790 <         */
4791 <        public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
4792 <            (ConcurrentHashMapV8<K,V> map,
4793 <             ObjectToInt<Map.Entry<K,V>> transformer,
4794 <             int basis,
4795 <             IntByIntToInt reducer) {
4796 <            if (transformer == null || reducer == null)
4797 <                throw new NullPointerException();
4798 <            return new MapReduceEntriesToIntTask<K,V>
4799 <                (map, transformer, basis, reducer);
4490 >        public void forEach(Action<? super V> action) {
4491 >            if (action == null) throw new NullPointerException();
4492 >            Node<K,V>[] t;
4493 >            if ((t = map.table) != null) {
4494 >                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4495 >                for (Node<K,V> p; (p = it.advance()) != null; )
4496 >                    action.apply(p.val);
4497 >            }
4498          }
4499      }
4500  
4803    // -------------------------------------------------------
4804
4501      /**
4502 <     * Base for FJ tasks for bulk operations. This adds a variant of
4503 <     * CountedCompleters and some split and merge bookkeeping to
4504 <     * iterator functionality. The forEach and reduce methods are
4505 <     * similar to those illustrated in CountedCompleter documentation,
4506 <     * except that bottom-up reduction completions perform them within
4507 <     * their compute methods. The search methods are like forEach
4508 <     * except they continually poll for success and exit early.  Also,
4509 <     * exceptions are handled in a simpler manner, by just trying to
4814 <     * complete root task exceptionally.
4815 <     */
4816 <    @SuppressWarnings("serial") static abstract class BulkTask<K,V,R> extends Traverser<K,V,R> {
4817 <        final BulkTask<K,V,?> parent;  // completion target
4818 <        int batch;                     // split control
4819 <        int pending;                   // completion control
4502 >     * A view of a ConcurrentHashMapV8 as a {@link Set} of (key, value)
4503 >     * entries.  This class cannot be directly instantiated. See
4504 >     * {@link #entrySet()}.
4505 >     */
4506 >    static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4507 >        implements Set<Map.Entry<K,V>>, java.io.Serializable {
4508 >        private static final long serialVersionUID = 2249069246763182397L;
4509 >        EntrySetView(ConcurrentHashMapV8<K,V> map) { super(map); }
4510  
4511 <        /** Constructor for root tasks */
4512 <        BulkTask(ConcurrentHashMapV8<K,V> map) {
4513 <            super(map);
4514 <            this.parent = null;
4515 <            this.batch = -1; // force call to batch() on execution
4511 >        public boolean contains(Object o) {
4512 >            Object k, v, r; Map.Entry<?,?> e;
4513 >            return ((o instanceof Map.Entry) &&
4514 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4515 >                    (r = map.get(k)) != null &&
4516 >                    (v = e.getValue()) != null &&
4517 >                    (v == r || v.equals(r)));
4518          }
4519  
4520 <        /** Constructor for subtasks */
4521 <        BulkTask(BulkTask<K,V,?> parent, int batch) {
4522 <            super(parent);
4523 <            this.parent = parent;
4524 <            this.batch = batch;
4520 >        public boolean remove(Object o) {
4521 >            Object k, v; Map.Entry<?,?> e;
4522 >            return ((o instanceof Map.Entry) &&
4523 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4524 >                    (v = e.getValue()) != null &&
4525 >                    map.remove(k, v));
4526          }
4527  
4835        // FJ methods
4836
4528          /**
4529 <         * Propagates completion. Note that all reduce actions
4839 <         * bypass this method to combine while completing.
4529 >         * @return an iterator over the entries of the backing map
4530           */
4531 <        final void tryComplete() {
4532 <            BulkTask<K,V,?> a = this, s = a;
4533 <            for (int c;;) {
4534 <                if ((c = a.pending) == 0) {
4535 <                    if ((a = (s = a).parent) == null) {
4536 <                        s.quietlyComplete();
4537 <                        break;
4538 <                    }
4539 <                }
4540 <                else if (U.compareAndSwapInt(a, PENDING, c, c - 1))
4541 <                    break;
4531 >        public Iterator<Map.Entry<K,V>> iterator() {
4532 >            ConcurrentHashMapV8<K,V> m = map;
4533 >            Node<K,V>[] t;
4534 >            int f = (t = m.table) == null ? 0 : t.length;
4535 >            return new EntryIterator<K,V>(t, f, 0, f, m);
4536 >        }
4537 >
4538 >        public boolean add(Entry<K,V> e) {
4539 >            return map.putVal(e.getKey(), e.getValue(), false) == null;
4540 >        }
4541 >
4542 >        public boolean addAll(Collection<? extends Entry<K,V>> c) {
4543 >            boolean added = false;
4544 >            for (Entry<K,V> e : c) {
4545 >                if (add(e))
4546 >                    added = true;
4547              }
4548 +            return added;
4549          }
4550  
4551 <        /**
4552 <         * Forces root task to complete.
4553 <         * @param ex if null, complete normally, else exceptionally
4554 <         * @return false to simplify use
4555 <         */
4556 <        final boolean tryCompleteComputation(Throwable ex) {
4557 <            for (BulkTask<K,V,?> a = this;;) {
4862 <                BulkTask<K,V,?> p = a.parent;
4863 <                if (p == null) {
4864 <                    if (ex != null)
4865 <                        a.completeExceptionally(ex);
4866 <                    else
4867 <                        a.quietlyComplete();
4868 <                    return false;
4551 >        public final int hashCode() {
4552 >            int h = 0;
4553 >            Node<K,V>[] t;
4554 >            if ((t = map.table) != null) {
4555 >                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4556 >                for (Node<K,V> p; (p = it.advance()) != null; ) {
4557 >                    h += p.hashCode();
4558                  }
4870                a = p;
4559              }
4560 +            return h;
4561          }
4562  
4563 <        /**
4564 <         * Version of tryCompleteComputation for function screening checks
4565 <         */
4566 <        final boolean abortOnNullFunction() {
4567 <            return tryCompleteComputation(new Error("Unexpected null function"));
4563 >        public final boolean equals(Object o) {
4564 >            Set<?> c;
4565 >            return ((o instanceof Set) &&
4566 >                    ((c = (Set<?>)o) == this ||
4567 >                     (containsAll(c) && c.containsAll(this))));
4568          }
4569  
4570 <        // utilities
4570 >        public ConcurrentHashMapSpliterator<Map.Entry<K,V>> spliterator() {
4571 >            Node<K,V>[] t;
4572 >            ConcurrentHashMapV8<K,V> m = map;
4573 >            long n = m.sumCount();
4574 >            int f = (t = m.table) == null ? 0 : t.length;
4575 >            return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4576 >        }
4577  
4578 <        /** CompareAndSet pending count */
4579 <        final boolean casPending(int cmp, int val) {
4580 <            return U.compareAndSwapInt(this, PENDING, cmp, val);
4578 >        public void forEach(Action<? super Map.Entry<K,V>> action) {
4579 >            if (action == null) throw new NullPointerException();
4580 >            Node<K,V>[] t;
4581 >            if ((t = map.table) != null) {
4582 >                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4583 >                for (Node<K,V> p; (p = it.advance()) != null; )
4584 >                    action.apply(new MapEntry<K,V>(p.key, p.val, map));
4585 >            }
4586          }
4587  
4588 <        /**
4589 <         * Returns approx exp2 of the number of times (minus one) to
4590 <         * split task by two before executing leaf action. This value
4591 <         * is faster to compute and more convenient to use as a guide
4592 <         * to splitting than is the depth, since it is used while
4593 <         * dividing by two anyway.
4594 <         */
4595 <        final int batch() {
4596 <            int b = batch;
4597 <            if (b < 0) {
4598 <                long n = map.counter.sum();
4599 <                int sp = getPool().getParallelism() << 3; // slack of 8
4600 <                b = batch = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
4588 >    }
4589 >
4590 >    // -------------------------------------------------------
4591 >
4592 >    /**
4593 >     * Base class for bulk tasks. Repeats some fields and code from
4594 >     * class Traverser, because we need to subclass CountedCompleter.
4595 >     */
4596 >    abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4597 >        Node<K,V>[] tab;        // same as Traverser
4598 >        Node<K,V> next;
4599 >        int index;
4600 >        int baseIndex;
4601 >        int baseLimit;
4602 >        final int baseSize;
4603 >        int batch;              // split control
4604 >
4605 >        BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4606 >            super(par);
4607 >            this.batch = b;
4608 >            this.index = this.baseIndex = i;
4609 >            if ((this.tab = t) == null)
4610 >                this.baseSize = this.baseLimit = 0;
4611 >            else if (par == null)
4612 >                this.baseSize = this.baseLimit = t.length;
4613 >            else {
4614 >                this.baseLimit = f;
4615 >                this.baseSize = par.baseSize;
4616              }
4902            return b;
4617          }
4618  
4619          /**
4620 <         * Returns exportable snapshot entry.
4620 >         * Same as Traverser version
4621           */
4622 <        static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
4623 <            return new AbstractMap.SimpleEntry<K,V>(k, v);
4624 <        }
4625 <
4626 <        // Unsafe mechanics
4627 <        private static final sun.misc.Unsafe U;
4628 <        private static final long PENDING;
4629 <        static {
4630 <            try {
4631 <                U = getUnsafe();
4632 <                PENDING = U.objectFieldOffset
4633 <                    (BulkTask.class.getDeclaredField("pending"));
4634 <            } catch (Exception e) {
4635 <                throw new Error(e);
4622 >        final Node<K,V> advance() {
4623 >            Node<K,V> e;
4624 >            if ((e = next) != null)
4625 >                e = e.next;
4626 >            for (;;) {
4627 >                Node<K,V>[] t; int i, n; K ek;  // must use locals in checks
4628 >                if (e != null)
4629 >                    return next = e;
4630 >                if (baseIndex >= baseLimit || (t = tab) == null ||
4631 >                    (n = t.length) <= (i = index) || i < 0)
4632 >                    return next = null;
4633 >                if ((e = tabAt(t, index)) != null && e.hash < 0) {
4634 >                    if (e instanceof ForwardingNode) {
4635 >                        tab = ((ForwardingNode<K,V>)e).nextTable;
4636 >                        e = null;
4637 >                        continue;
4638 >                    }
4639 >                    else if (e instanceof TreeBin)
4640 >                        e = ((TreeBin<K,V>)e).first;
4641 >                    else
4642 >                        e = null;
4643 >                }
4644 >                if ((index += baseSize) >= n)
4645 >                    index = ++baseIndex;    // visit upper slots if present
4646              }
4647          }
4648      }
# Line 4926 | Line 4650 | public class ConcurrentHashMapV8<K, V>
4650      /*
4651       * Task classes. Coded in a regular but ugly format/style to
4652       * simplify checks that each variant differs in the right way from
4653 <     * others.
4653 >     * others. The null screenings exist because compilers cannot tell
4654 >     * that we've already null-checked task arguments, so we force
4655 >     * simplest hoisted bypass to help avoid convoluted traps.
4656       */
4657 <
4658 <    @SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
4657 >    @SuppressWarnings("serial")
4658 >    static final class ForEachKeyTask<K,V>
4659          extends BulkTask<K,V,Void> {
4660 <        final Action<K> action;
4660 >        final Action<? super K> action;
4661          ForEachKeyTask
4662 <            (ConcurrentHashMapV8<K,V> m,
4663 <             Action<K> action) {
4664 <            super(m);
4662 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4663 >             Action<? super K> action) {
4664 >            super(p, b, i, f, t);
4665              this.action = action;
4666          }
4667 <        ForEachKeyTask
4668 <            (BulkTask<K,V,?> p, int b,
4669 <             Action<K> action) {
4670 <            super(p, b);
4671 <            this.action = action;
4672 <        }
4673 <        @SuppressWarnings("unchecked") public final boolean exec() {
4674 <            final Action<K> action = this.action;
4675 <            if (action == null)
4676 <                return abortOnNullFunction();
4677 <            try {
4678 <                int b = batch(), c;
4679 <                while (b > 1 && baseIndex != baseLimit) {
4954 <                    do {} while (!casPending(c = pending, c+1));
4955 <                    new ForEachKeyTask<K,V>(this, b >>>= 1, action).fork();
4956 <                }
4957 <                while (advance() != null)
4958 <                    action.apply((K)nextKey);
4959 <                tryComplete();
4960 <            } catch (Throwable ex) {
4961 <                return tryCompleteComputation(ex);
4667 >        public final void compute() {
4668 >            final Action<? super K> action;
4669 >            if ((action = this.action) != null) {
4670 >                for (int i = baseIndex, f, h; batch > 0 &&
4671 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4672 >                    addToPendingCount(1);
4673 >                    new ForEachKeyTask<K,V>
4674 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4675 >                         action).fork();
4676 >                }
4677 >                for (Node<K,V> p; (p = advance()) != null;)
4678 >                    action.apply(p.key);
4679 >                propagateCompletion();
4680              }
4963            return false;
4681          }
4682      }
4683  
4684 <    @SuppressWarnings("serial") static final class ForEachValueTask<K,V>
4684 >    @SuppressWarnings("serial")
4685 >    static final class ForEachValueTask<K,V>
4686          extends BulkTask<K,V,Void> {
4687 <        final Action<V> action;
4687 >        final Action<? super V> action;
4688          ForEachValueTask
4689 <            (ConcurrentHashMapV8<K,V> m,
4690 <             Action<V> action) {
4691 <            super(m);
4689 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4690 >             Action<? super V> action) {
4691 >            super(p, b, i, f, t);
4692              this.action = action;
4693          }
4694 <        ForEachValueTask
4695 <            (BulkTask<K,V,?> p, int b,
4696 <             Action<V> action) {
4697 <            super(p, b);
4698 <            this.action = action;
4699 <        }
4700 <        @SuppressWarnings("unchecked") public final boolean exec() {
4701 <            final Action<V> action = this.action;
4702 <            if (action == null)
4703 <                return abortOnNullFunction();
4704 <            try {
4705 <                int b = batch(), c;
4706 <                while (b > 1 && baseIndex != baseLimit) {
4989 <                    do {} while (!casPending(c = pending, c+1));
4990 <                    new ForEachValueTask<K,V>(this, b >>>= 1, action).fork();
4991 <                }
4992 <                Object v;
4993 <                while ((v = advance()) != null)
4994 <                    action.apply((V)v);
4995 <                tryComplete();
4996 <            } catch (Throwable ex) {
4997 <                return tryCompleteComputation(ex);
4694 >        public final void compute() {
4695 >            final Action<? super V> action;
4696 >            if ((action = this.action) != null) {
4697 >                for (int i = baseIndex, f, h; batch > 0 &&
4698 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4699 >                    addToPendingCount(1);
4700 >                    new ForEachValueTask<K,V>
4701 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4702 >                         action).fork();
4703 >                }
4704 >                for (Node<K,V> p; (p = advance()) != null;)
4705 >                    action.apply(p.val);
4706 >                propagateCompletion();
4707              }
4999            return false;
4708          }
4709      }
4710  
4711 <    @SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
4711 >    @SuppressWarnings("serial")
4712 >    static final class ForEachEntryTask<K,V>
4713          extends BulkTask<K,V,Void> {
4714 <        final Action<Entry<K,V>> action;
4714 >        final Action<? super Entry<K,V>> action;
4715          ForEachEntryTask
4716 <            (ConcurrentHashMapV8<K,V> m,
4717 <             Action<Entry<K,V>> action) {
4718 <            super(m);
4716 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4717 >             Action<? super Entry<K,V>> action) {
4718 >            super(p, b, i, f, t);
4719              this.action = action;
4720          }
4721 <        ForEachEntryTask
4722 <            (BulkTask<K,V,?> p, int b,
4723 <             Action<Entry<K,V>> action) {
4724 <            super(p, b);
4725 <            this.action = action;
4726 <        }
4727 <        @SuppressWarnings("unchecked") public final boolean exec() {
4728 <            final Action<Entry<K,V>> action = this.action;
4729 <            if (action == null)
4730 <                return abortOnNullFunction();
4731 <            try {
4732 <                int b = batch(), c;
4733 <                while (b > 1 && baseIndex != baseLimit) {
5025 <                    do {} while (!casPending(c = pending, c+1));
5026 <                    new ForEachEntryTask<K,V>(this, b >>>= 1, action).fork();
5027 <                }
5028 <                Object v;
5029 <                while ((v = advance()) != null)
5030 <                    action.apply(entryFor((K)nextKey, (V)v));
5031 <                tryComplete();
5032 <            } catch (Throwable ex) {
5033 <                return tryCompleteComputation(ex);
4721 >        public final void compute() {
4722 >            final Action<? super Entry<K,V>> action;
4723 >            if ((action = this.action) != null) {
4724 >                for (int i = baseIndex, f, h; batch > 0 &&
4725 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4726 >                    addToPendingCount(1);
4727 >                    new ForEachEntryTask<K,V>
4728 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4729 >                         action).fork();
4730 >                }
4731 >                for (Node<K,V> p; (p = advance()) != null; )
4732 >                    action.apply(p);
4733 >                propagateCompletion();
4734              }
5035            return false;
4735          }
4736      }
4737  
4738 <    @SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
4738 >    @SuppressWarnings("serial")
4739 >    static final class ForEachMappingTask<K,V>
4740          extends BulkTask<K,V,Void> {
4741 <        final BiAction<K,V> action;
4741 >        final BiAction<? super K, ? super V> action;
4742          ForEachMappingTask
4743 <            (ConcurrentHashMapV8<K,V> m,
4744 <             BiAction<K,V> action) {
4745 <            super(m);
4743 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4744 >             BiAction<? super K,? super V> action) {
4745 >            super(p, b, i, f, t);
4746              this.action = action;
4747          }
4748 <        ForEachMappingTask
4749 <            (BulkTask<K,V,?> p, int b,
4750 <             BiAction<K,V> action) {
4751 <            super(p, b);
4752 <            this.action = action;
4753 <        }
4754 <
4755 <        @SuppressWarnings("unchecked") public final boolean exec() {
4756 <            final BiAction<K,V> action = this.action;
4757 <            if (action == null)
4758 <                return abortOnNullFunction();
4759 <            try {
4760 <                int b = batch(), c;
5061 <                while (b > 1 && baseIndex != baseLimit) {
5062 <                    do {} while (!casPending(c = pending, c+1));
5063 <                    new ForEachMappingTask<K,V>(this, b >>>= 1,
5064 <                                                action).fork();
5065 <                }
5066 <                Object v;
5067 <                while ((v = advance()) != null)
5068 <                    action.apply((K)nextKey, (V)v);
5069 <                tryComplete();
5070 <            } catch (Throwable ex) {
5071 <                return tryCompleteComputation(ex);
4748 >        public final void compute() {
4749 >            final BiAction<? super K, ? super V> action;
4750 >            if ((action = this.action) != null) {
4751 >                for (int i = baseIndex, f, h; batch > 0 &&
4752 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4753 >                    addToPendingCount(1);
4754 >                    new ForEachMappingTask<K,V>
4755 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4756 >                         action).fork();
4757 >                }
4758 >                for (Node<K,V> p; (p = advance()) != null; )
4759 >                    action.apply(p.key, p.val);
4760 >                propagateCompletion();
4761              }
5073            return false;
4762          }
4763      }
4764  
4765 <    @SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
4765 >    @SuppressWarnings("serial")
4766 >    static final class ForEachTransformedKeyTask<K,V,U>
4767          extends BulkTask<K,V,Void> {
4768          final Fun<? super K, ? extends U> transformer;
4769 <        final Action<U> action;
5081 <        ForEachTransformedKeyTask
5082 <            (ConcurrentHashMapV8<K,V> m,
5083 <             Fun<? super K, ? extends U> transformer,
5084 <             Action<U> action) {
5085 <            super(m);
5086 <            this.transformer = transformer;
5087 <            this.action = action;
5088 <
5089 <        }
4769 >        final Action<? super U> action;
4770          ForEachTransformedKeyTask
4771 <            (BulkTask<K,V,?> p, int b,
4772 <             Fun<? super K, ? extends U> transformer,
4773 <             Action<U> action) {
4774 <            super(p, b);
4775 <            this.transformer = transformer;
4776 <            this.action = action;
4777 <        }
4778 <        @SuppressWarnings("unchecked") public final boolean exec() {
4779 <            final Fun<? super K, ? extends U> transformer =
4780 <                this.transformer;
4781 <            final Action<U> action = this.action;
4782 <            if (transformer == null || action == null)
4783 <                return abortOnNullFunction();
5104 <            try {
5105 <                int b = batch(), c;
5106 <                while (b > 1 && baseIndex != baseLimit) {
5107 <                    do {} while (!casPending(c = pending, c+1));
4771 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4772 >             Fun<? super K, ? extends U> transformer, Action<? super U> action) {
4773 >            super(p, b, i, f, t);
4774 >            this.transformer = transformer; this.action = action;
4775 >        }
4776 >        public final void compute() {
4777 >            final Fun<? super K, ? extends U> transformer;
4778 >            final Action<? super U> action;
4779 >            if ((transformer = this.transformer) != null &&
4780 >                (action = this.action) != null) {
4781 >                for (int i = baseIndex, f, h; batch > 0 &&
4782 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4783 >                    addToPendingCount(1);
4784                      new ForEachTransformedKeyTask<K,V,U>
4785 <                        (this, b >>>= 1, transformer, action).fork();
4785 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4786 >                         transformer, action).fork();
4787                  }
4788 <                U u;
4789 <                while (advance() != null) {
4790 <                    if ((u = transformer.apply((K)nextKey)) != null)
4788 >                for (Node<K,V> p; (p = advance()) != null; ) {
4789 >                    U u;
4790 >                    if ((u = transformer.apply(p.key)) != null)
4791                          action.apply(u);
4792                  }
4793 <                tryComplete();
5117 <            } catch (Throwable ex) {
5118 <                return tryCompleteComputation(ex);
4793 >                propagateCompletion();
4794              }
5120            return false;
4795          }
4796      }
4797  
4798 <    @SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
4798 >    @SuppressWarnings("serial")
4799 >    static final class ForEachTransformedValueTask<K,V,U>
4800          extends BulkTask<K,V,Void> {
4801          final Fun<? super V, ? extends U> transformer;
4802 <        final Action<U> action;
4802 >        final Action<? super U> action;
4803          ForEachTransformedValueTask
4804 <            (ConcurrentHashMapV8<K,V> m,
4805 <             Fun<? super V, ? extends U> transformer,
4806 <             Action<U> action) {
4807 <            super(m);
4808 <            this.transformer = transformer;
4809 <            this.action = action;
4810 <
4811 <        }
4812 <        ForEachTransformedValueTask
4813 <            (BulkTask<K,V,?> p, int b,
4814 <             Fun<? super V, ? extends U> transformer,
4815 <             Action<U> action) {
4816 <            super(p, b);
5142 <            this.transformer = transformer;
5143 <            this.action = action;
5144 <        }
5145 <        @SuppressWarnings("unchecked") public final boolean exec() {
5146 <            final Fun<? super V, ? extends U> transformer =
5147 <                this.transformer;
5148 <            final Action<U> action = this.action;
5149 <            if (transformer == null || action == null)
5150 <                return abortOnNullFunction();
5151 <            try {
5152 <                int b = batch(), c;
5153 <                while (b > 1 && baseIndex != baseLimit) {
5154 <                    do {} while (!casPending(c = pending, c+1));
4804 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4805 >             Fun<? super V, ? extends U> transformer, Action<? super U> action) {
4806 >            super(p, b, i, f, t);
4807 >            this.transformer = transformer; this.action = action;
4808 >        }
4809 >        public final void compute() {
4810 >            final Fun<? super V, ? extends U> transformer;
4811 >            final Action<? super U> action;
4812 >            if ((transformer = this.transformer) != null &&
4813 >                (action = this.action) != null) {
4814 >                for (int i = baseIndex, f, h; batch > 0 &&
4815 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4816 >                    addToPendingCount(1);
4817                      new ForEachTransformedValueTask<K,V,U>
4818 <                        (this, b >>>= 1, transformer, action).fork();
4818 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4819 >                         transformer, action).fork();
4820                  }
4821 <                Object v; U u;
4822 <                while ((v = advance()) != null) {
4823 <                    if ((u = transformer.apply((V)v)) != null)
4821 >                for (Node<K,V> p; (p = advance()) != null; ) {
4822 >                    U u;
4823 >                    if ((u = transformer.apply(p.val)) != null)
4824                          action.apply(u);
4825                  }
4826 <                tryComplete();
5164 <            } catch (Throwable ex) {
5165 <                return tryCompleteComputation(ex);
4826 >                propagateCompletion();
4827              }
5167            return false;
4828          }
4829      }
4830  
4831 <    @SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
4831 >    @SuppressWarnings("serial")
4832 >    static final class ForEachTransformedEntryTask<K,V,U>
4833          extends BulkTask<K,V,Void> {
4834          final Fun<Map.Entry<K,V>, ? extends U> transformer;
4835 <        final Action<U> action;
5175 <        ForEachTransformedEntryTask
5176 <            (ConcurrentHashMapV8<K,V> m,
5177 <             Fun<Map.Entry<K,V>, ? extends U> transformer,
5178 <             Action<U> action) {
5179 <            super(m);
5180 <            this.transformer = transformer;
5181 <            this.action = action;
5182 <
5183 <        }
4835 >        final Action<? super U> action;
4836          ForEachTransformedEntryTask
4837 <            (BulkTask<K,V,?> p, int b,
4838 <             Fun<Map.Entry<K,V>, ? extends U> transformer,
4839 <             Action<U> action) {
4840 <            super(p, b);
4841 <            this.transformer = transformer;
4842 <            this.action = action;
4843 <        }
4844 <        @SuppressWarnings("unchecked") public final boolean exec() {
4845 <            final Fun<Map.Entry<K,V>, ? extends U> transformer =
4846 <                this.transformer;
4847 <            final Action<U> action = this.action;
4848 <            if (transformer == null || action == null)
4849 <                return abortOnNullFunction();
5198 <            try {
5199 <                int b = batch(), c;
5200 <                while (b > 1 && baseIndex != baseLimit) {
5201 <                    do {} while (!casPending(c = pending, c+1));
4837 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4838 >             Fun<Map.Entry<K,V>, ? extends U> transformer, Action<? super U> action) {
4839 >            super(p, b, i, f, t);
4840 >            this.transformer = transformer; this.action = action;
4841 >        }
4842 >        public final void compute() {
4843 >            final Fun<Map.Entry<K,V>, ? extends U> transformer;
4844 >            final Action<? super U> action;
4845 >            if ((transformer = this.transformer) != null &&
4846 >                (action = this.action) != null) {
4847 >                for (int i = baseIndex, f, h; batch > 0 &&
4848 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4849 >                    addToPendingCount(1);
4850                      new ForEachTransformedEntryTask<K,V,U>
4851 <                        (this, b >>>= 1, transformer, action).fork();
4851 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4852 >                         transformer, action).fork();
4853                  }
4854 <                Object v; U u;
4855 <                while ((v = advance()) != null) {
4856 <                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
4854 >                for (Node<K,V> p; (p = advance()) != null; ) {
4855 >                    U u;
4856 >                    if ((u = transformer.apply(p)) != null)
4857                          action.apply(u);
4858                  }
4859 <                tryComplete();
5211 <            } catch (Throwable ex) {
5212 <                return tryCompleteComputation(ex);
4859 >                propagateCompletion();
4860              }
5214            return false;
4861          }
4862      }
4863  
4864 <    @SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
4864 >    @SuppressWarnings("serial")
4865 >    static final class ForEachTransformedMappingTask<K,V,U>
4866          extends BulkTask<K,V,Void> {
4867          final BiFun<? super K, ? super V, ? extends U> transformer;
4868 <        final Action<U> action;
4868 >        final Action<? super U> action;
4869          ForEachTransformedMappingTask
4870 <            (ConcurrentHashMapV8<K,V> m,
4870 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4871               BiFun<? super K, ? super V, ? extends U> transformer,
4872 <             Action<U> action) {
4873 <            super(m);
4874 <            this.transformer = transformer;
4875 <            this.action = action;
4876 <
4877 <        }
4878 <        ForEachTransformedMappingTask
4879 <            (BulkTask<K,V,?> p, int b,
4880 <             BiFun<? super K, ? super V, ? extends U> transformer,
4881 <             Action<U> action) {
4882 <            super(p, b);
4883 <            this.transformer = transformer;
5237 <            this.action = action;
5238 <        }
5239 <        @SuppressWarnings("unchecked") public final boolean exec() {
5240 <            final BiFun<? super K, ? super V, ? extends U> transformer =
5241 <                this.transformer;
5242 <            final Action<U> action = this.action;
5243 <            if (transformer == null || action == null)
5244 <                return abortOnNullFunction();
5245 <            try {
5246 <                int b = batch(), c;
5247 <                while (b > 1 && baseIndex != baseLimit) {
5248 <                    do {} while (!casPending(c = pending, c+1));
4872 >             Action<? super U> action) {
4873 >            super(p, b, i, f, t);
4874 >            this.transformer = transformer; this.action = action;
4875 >        }
4876 >        public final void compute() {
4877 >            final BiFun<? super K, ? super V, ? extends U> transformer;
4878 >            final Action<? super U> action;
4879 >            if ((transformer = this.transformer) != null &&
4880 >                (action = this.action) != null) {
4881 >                for (int i = baseIndex, f, h; batch > 0 &&
4882 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4883 >                    addToPendingCount(1);
4884                      new ForEachTransformedMappingTask<K,V,U>
4885 <                        (this, b >>>= 1, transformer, action).fork();
4885 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4886 >                         transformer, action).fork();
4887                  }
4888 <                Object v; U u;
4889 <                while ((v = advance()) != null) {
4890 <                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
4888 >                for (Node<K,V> p; (p = advance()) != null; ) {
4889 >                    U u;
4890 >                    if ((u = transformer.apply(p.key, p.val)) != null)
4891                          action.apply(u);
4892                  }
4893 <                tryComplete();
5258 <            } catch (Throwable ex) {
5259 <                return tryCompleteComputation(ex);
4893 >                propagateCompletion();
4894              }
5261            return false;
4895          }
4896      }
4897  
4898 <    @SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
4898 >    @SuppressWarnings("serial")
4899 >    static final class SearchKeysTask<K,V,U>
4900          extends BulkTask<K,V,U> {
4901          final Fun<? super K, ? extends U> searchFunction;
4902          final AtomicReference<U> result;
4903          SearchKeysTask
4904 <            (ConcurrentHashMapV8<K,V> m,
5271 <             Fun<? super K, ? extends U> searchFunction,
5272 <             AtomicReference<U> result) {
5273 <            super(m);
5274 <            this.searchFunction = searchFunction; this.result = result;
5275 <        }
5276 <        SearchKeysTask
5277 <            (BulkTask<K,V,?> p, int b,
4904 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4905               Fun<? super K, ? extends U> searchFunction,
4906               AtomicReference<U> result) {
4907 <            super(p, b);
4907 >            super(p, b, i, f, t);
4908              this.searchFunction = searchFunction; this.result = result;
4909          }
4910 <        @SuppressWarnings("unchecked") public final boolean exec() {
4911 <            AtomicReference<U> result = this.result;
4912 <            final Fun<? super K, ? extends U> searchFunction =
4913 <                this.searchFunction;
4914 <            if (searchFunction == null || result == null)
4915 <                return abortOnNullFunction();
4916 <            try {
4917 <                int b = batch(), c;
4918 <                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
4919 <                    do {} while (!casPending(c = pending, c+1));
4920 <                    new SearchKeysTask<K,V,U>(this, b >>>= 1,
4921 <                                              searchFunction, result).fork();
4922 <                }
4923 <                U u;
4924 <                while (result.get() == null && advance() != null) {
4925 <                    if ((u = searchFunction.apply((K)nextKey)) != null) {
4910 >        public final U getRawResult() { return result.get(); }
4911 >        public final void compute() {
4912 >            final Fun<? super K, ? extends U> searchFunction;
4913 >            final AtomicReference<U> result;
4914 >            if ((searchFunction = this.searchFunction) != null &&
4915 >                (result = this.result) != null) {
4916 >                for (int i = baseIndex, f, h; batch > 0 &&
4917 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4918 >                    if (result.get() != null)
4919 >                        return;
4920 >                    addToPendingCount(1);
4921 >                    new SearchKeysTask<K,V,U>
4922 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4923 >                         searchFunction, result).fork();
4924 >                }
4925 >                while (result.get() == null) {
4926 >                    U u;
4927 >                    Node<K,V> p;
4928 >                    if ((p = advance()) == null) {
4929 >                        propagateCompletion();
4930 >                        break;
4931 >                    }
4932 >                    if ((u = searchFunction.apply(p.key)) != null) {
4933                          if (result.compareAndSet(null, u))
4934 <                            tryCompleteComputation(null);
4934 >                            quietlyCompleteRoot();
4935                          break;
4936                      }
4937                  }
5304                tryComplete();
5305            } catch (Throwable ex) {
5306                return tryCompleteComputation(ex);
4938              }
5308            return false;
4939          }
5310        public final U getRawResult() { return result.get(); }
4940      }
4941  
4942 <    @SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
4942 >    @SuppressWarnings("serial")
4943 >    static final class SearchValuesTask<K,V,U>
4944          extends BulkTask<K,V,U> {
4945          final Fun<? super V, ? extends U> searchFunction;
4946          final AtomicReference<U> result;
4947          SearchValuesTask
4948 <            (ConcurrentHashMapV8<K,V> m,
5319 <             Fun<? super V, ? extends U> searchFunction,
5320 <             AtomicReference<U> result) {
5321 <            super(m);
5322 <            this.searchFunction = searchFunction; this.result = result;
5323 <        }
5324 <        SearchValuesTask
5325 <            (BulkTask<K,V,?> p, int b,
4948 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4949               Fun<? super V, ? extends U> searchFunction,
4950               AtomicReference<U> result) {
4951 <            super(p, b);
4951 >            super(p, b, i, f, t);
4952              this.searchFunction = searchFunction; this.result = result;
4953          }
4954 <        @SuppressWarnings("unchecked") public final boolean exec() {
4955 <            AtomicReference<U> result = this.result;
4956 <            final Fun<? super V, ? extends U> searchFunction =
4957 <                this.searchFunction;
4958 <            if (searchFunction == null || result == null)
4959 <                return abortOnNullFunction();
4960 <            try {
4961 <                int b = batch(), c;
4962 <                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
4963 <                    do {} while (!casPending(c = pending, c+1));
4964 <                    new SearchValuesTask<K,V,U>(this, b >>>= 1,
4965 <                                                searchFunction, result).fork();
4966 <                }
4967 <                Object v; U u;
4968 <                while (result.get() == null && (v = advance()) != null) {
4969 <                    if ((u = searchFunction.apply((V)v)) != null) {
4954 >        public final U getRawResult() { return result.get(); }
4955 >        public final void compute() {
4956 >            final Fun<? super V, ? extends U> searchFunction;
4957 >            final AtomicReference<U> result;
4958 >            if ((searchFunction = this.searchFunction) != null &&
4959 >                (result = this.result) != null) {
4960 >                for (int i = baseIndex, f, h; batch > 0 &&
4961 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4962 >                    if (result.get() != null)
4963 >                        return;
4964 >                    addToPendingCount(1);
4965 >                    new SearchValuesTask<K,V,U>
4966 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4967 >                         searchFunction, result).fork();
4968 >                }
4969 >                while (result.get() == null) {
4970 >                    U u;
4971 >                    Node<K,V> p;
4972 >                    if ((p = advance()) == null) {
4973 >                        propagateCompletion();
4974 >                        break;
4975 >                    }
4976 >                    if ((u = searchFunction.apply(p.val)) != null) {
4977                          if (result.compareAndSet(null, u))
4978 <                            tryCompleteComputation(null);
4978 >                            quietlyCompleteRoot();
4979                          break;
4980                      }
4981                  }
5352                tryComplete();
5353            } catch (Throwable ex) {
5354                return tryCompleteComputation(ex);
4982              }
5356            return false;
4983          }
5358        public final U getRawResult() { return result.get(); }
4984      }
4985  
4986 <    @SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
4986 >    @SuppressWarnings("serial")
4987 >    static final class SearchEntriesTask<K,V,U>
4988          extends BulkTask<K,V,U> {
4989          final Fun<Entry<K,V>, ? extends U> searchFunction;
4990          final AtomicReference<U> result;
4991          SearchEntriesTask
4992 <            (ConcurrentHashMapV8<K,V> m,
5367 <             Fun<Entry<K,V>, ? extends U> searchFunction,
5368 <             AtomicReference<U> result) {
5369 <            super(m);
5370 <            this.searchFunction = searchFunction; this.result = result;
5371 <        }
5372 <        SearchEntriesTask
5373 <            (BulkTask<K,V,?> p, int b,
4992 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4993               Fun<Entry<K,V>, ? extends U> searchFunction,
4994               AtomicReference<U> result) {
4995 <            super(p, b);
4995 >            super(p, b, i, f, t);
4996              this.searchFunction = searchFunction; this.result = result;
4997          }
4998 <        @SuppressWarnings("unchecked") public final boolean exec() {
4999 <            AtomicReference<U> result = this.result;
5000 <            final Fun<Entry<K,V>, ? extends U> searchFunction =
5001 <                this.searchFunction;
5002 <            if (searchFunction == null || result == null)
5003 <                return abortOnNullFunction();
5004 <            try {
5005 <                int b = batch(), c;
5006 <                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5007 <                    do {} while (!casPending(c = pending, c+1));
5008 <                    new SearchEntriesTask<K,V,U>(this, b >>>= 1,
5009 <                                                 searchFunction, result).fork();
5010 <                }
5011 <                Object v; U u;
5012 <                while (result.get() == null && (v = advance()) != null) {
5013 <                    if ((u = searchFunction.apply(entryFor((K)nextKey, (V)v))) != null) {
5014 <                        if (result.compareAndSet(null, u))
5015 <                            tryCompleteComputation(null);
4998 >        public final U getRawResult() { return result.get(); }
4999 >        public final void compute() {
5000 >            final Fun<Entry<K,V>, ? extends U> searchFunction;
5001 >            final AtomicReference<U> result;
5002 >            if ((searchFunction = this.searchFunction) != null &&
5003 >                (result = this.result) != null) {
5004 >                for (int i = baseIndex, f, h; batch > 0 &&
5005 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5006 >                    if (result.get() != null)
5007 >                        return;
5008 >                    addToPendingCount(1);
5009 >                    new SearchEntriesTask<K,V,U>
5010 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
5011 >                         searchFunction, result).fork();
5012 >                }
5013 >                while (result.get() == null) {
5014 >                    U u;
5015 >                    Node<K,V> p;
5016 >                    if ((p = advance()) == null) {
5017 >                        propagateCompletion();
5018                          break;
5019                      }
5020 +                    if ((u = searchFunction.apply(p)) != null) {
5021 +                        if (result.compareAndSet(null, u))
5022 +                            quietlyCompleteRoot();
5023 +                        return;
5024 +                    }
5025                  }
5400                tryComplete();
5401            } catch (Throwable ex) {
5402                return tryCompleteComputation(ex);
5026              }
5404            return false;
5027          }
5406        public final U getRawResult() { return result.get(); }
5028      }
5029  
5030 <    @SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5030 >    @SuppressWarnings("serial")
5031 >    static final class SearchMappingsTask<K,V,U>
5032          extends BulkTask<K,V,U> {
5033          final BiFun<? super K, ? super V, ? extends U> searchFunction;
5034          final AtomicReference<U> result;
5035          SearchMappingsTask
5036 <            (ConcurrentHashMapV8<K,V> m,
5415 <             BiFun<? super K, ? super V, ? extends U> searchFunction,
5416 <             AtomicReference<U> result) {
5417 <            super(m);
5418 <            this.searchFunction = searchFunction; this.result = result;
5419 <        }
5420 <        SearchMappingsTask
5421 <            (BulkTask<K,V,?> p, int b,
5036 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5037               BiFun<? super K, ? super V, ? extends U> searchFunction,
5038               AtomicReference<U> result) {
5039 <            super(p, b);
5039 >            super(p, b, i, f, t);
5040              this.searchFunction = searchFunction; this.result = result;
5041          }
5042 <        @SuppressWarnings("unchecked") public final boolean exec() {
5043 <            AtomicReference<U> result = this.result;
5044 <            final BiFun<? super K, ? super V, ? extends U> searchFunction =
5045 <                this.searchFunction;
5046 <            if (searchFunction == null || result == null)
5047 <                return abortOnNullFunction();
5048 <            try {
5049 <                int b = batch(), c;
5050 <                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5051 <                    do {} while (!casPending(c = pending, c+1));
5052 <                    new SearchMappingsTask<K,V,U>(this, b >>>= 1,
5053 <                                                  searchFunction, result).fork();
5054 <                }
5055 <                Object v; U u;
5056 <                while (result.get() == null && (v = advance()) != null) {
5057 <                    if ((u = searchFunction.apply((K)nextKey, (V)v)) != null) {
5042 >        public final U getRawResult() { return result.get(); }
5043 >        public final void compute() {
5044 >            final BiFun<? super K, ? super V, ? extends U> searchFunction;
5045 >            final AtomicReference<U> result;
5046 >            if ((searchFunction = this.searchFunction) != null &&
5047 >                (result = this.result) != null) {
5048 >                for (int i = baseIndex, f, h; batch > 0 &&
5049 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5050 >                    if (result.get() != null)
5051 >                        return;
5052 >                    addToPendingCount(1);
5053 >                    new SearchMappingsTask<K,V,U>
5054 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
5055 >                         searchFunction, result).fork();
5056 >                }
5057 >                while (result.get() == null) {
5058 >                    U u;
5059 >                    Node<K,V> p;
5060 >                    if ((p = advance()) == null) {
5061 >                        propagateCompletion();
5062 >                        break;
5063 >                    }
5064 >                    if ((u = searchFunction.apply(p.key, p.val)) != null) {
5065                          if (result.compareAndSet(null, u))
5066 <                            tryCompleteComputation(null);
5066 >                            quietlyCompleteRoot();
5067                          break;
5068                      }
5069                  }
5448                tryComplete();
5449            } catch (Throwable ex) {
5450                return tryCompleteComputation(ex);
5070              }
5452            return false;
5071          }
5454        public final U getRawResult() { return result.get(); }
5072      }
5073  
5074 <    @SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5074 >    @SuppressWarnings("serial")
5075 >    static final class ReduceKeysTask<K,V>
5076          extends BulkTask<K,V,K> {
5077          final BiFun<? super K, ? super K, ? extends K> reducer;
5078          K result;
5079          ReduceKeysTask<K,V> rights, nextRight;
5080          ReduceKeysTask
5081 <            (ConcurrentHashMapV8<K,V> m,
5464 <             BiFun<? super K, ? super K, ? extends K> reducer) {
5465 <            super(m);
5466 <            this.reducer = reducer;
5467 <        }
5468 <        ReduceKeysTask
5469 <            (BulkTask<K,V,?> p, int b,
5081 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5082               ReduceKeysTask<K,V> nextRight,
5083               BiFun<? super K, ? super K, ? extends K> reducer) {
5084 <            super(p, b); this.nextRight = nextRight;
5084 >            super(p, b, i, f, t); this.nextRight = nextRight;
5085              this.reducer = reducer;
5086          }
5087 <
5088 <        @SuppressWarnings("unchecked") public final boolean exec() {
5089 <            final BiFun<? super K, ? super K, ? extends K> reducer =
5090 <                this.reducer;
5091 <            if (reducer == null)
5092 <                return abortOnNullFunction();
5093 <            try {
5482 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5483 <                    do {} while (!casPending(c = pending, c+1));
5087 >        public final K getRawResult() { return result; }
5088 >        public final void compute() {
5089 >            final BiFun<? super K, ? super K, ? extends K> reducer;
5090 >            if ((reducer = this.reducer) != null) {
5091 >                for (int i = baseIndex, f, h; batch > 0 &&
5092 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5093 >                    addToPendingCount(1);
5094                      (rights = new ReduceKeysTask<K,V>
5095 <                     (this, b >>>= 1, rights, reducer)).fork();
5095 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5096 >                      rights, reducer)).fork();
5097                  }
5098                  K r = null;
5099 <                while (advance() != null) {
5100 <                    K u = (K)nextKey;
5101 <                    r = (r == null) ? u : reducer.apply(r, u);
5099 >                for (Node<K,V> p; (p = advance()) != null; ) {
5100 >                    K u = p.key;
5101 >                    r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5102                  }
5103                  result = r;
5104 <                for (ReduceKeysTask<K,V> t = this, s;;) {
5105 <                    int c; BulkTask<K,V,?> par; K tr, sr;
5106 <                    if ((c = t.pending) == 0) {
5107 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5108 <                            if ((sr = s.result) != null)
5109 <                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5110 <                        }
5111 <                        if ((par = t.parent) == null ||
5112 <                            !(par instanceof ReduceKeysTask)) {
5113 <                            t.quietlyComplete();
5114 <                            break;
5504 <                        }
5505 <                        t = (ReduceKeysTask<K,V>)par;
5104 >                CountedCompleter<?> c;
5105 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5106 >                    @SuppressWarnings("unchecked") ReduceKeysTask<K,V>
5107 >                        t = (ReduceKeysTask<K,V>)c,
5108 >                        s = t.rights;
5109 >                    while (s != null) {
5110 >                        K tr, sr;
5111 >                        if ((sr = s.result) != null)
5112 >                            t.result = (((tr = t.result) == null) ? sr :
5113 >                                        reducer.apply(tr, sr));
5114 >                        s = t.rights = s.nextRight;
5115                      }
5507                    else if (t.casPending(c, c - 1))
5508                        break;
5116                  }
5510            } catch (Throwable ex) {
5511                return tryCompleteComputation(ex);
5117              }
5513            return false;
5118          }
5515        public final K getRawResult() { return result; }
5119      }
5120  
5121 <    @SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5121 >    @SuppressWarnings("serial")
5122 >    static final class ReduceValuesTask<K,V>
5123          extends BulkTask<K,V,V> {
5124          final BiFun<? super V, ? super V, ? extends V> reducer;
5125          V result;
5126          ReduceValuesTask<K,V> rights, nextRight;
5127          ReduceValuesTask
5128 <            (ConcurrentHashMapV8<K,V> m,
5525 <             BiFun<? super V, ? super V, ? extends V> reducer) {
5526 <            super(m);
5527 <            this.reducer = reducer;
5528 <        }
5529 <        ReduceValuesTask
5530 <            (BulkTask<K,V,?> p, int b,
5128 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5129               ReduceValuesTask<K,V> nextRight,
5130               BiFun<? super V, ? super V, ? extends V> reducer) {
5131 <            super(p, b); this.nextRight = nextRight;
5131 >            super(p, b, i, f, t); this.nextRight = nextRight;
5132              this.reducer = reducer;
5133          }
5134 <
5135 <        @SuppressWarnings("unchecked") public final boolean exec() {
5136 <            final BiFun<? super V, ? super V, ? extends V> reducer =
5137 <                this.reducer;
5138 <            if (reducer == null)
5139 <                return abortOnNullFunction();
5140 <            try {
5543 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5544 <                    do {} while (!casPending(c = pending, c+1));
5134 >        public final V getRawResult() { return result; }
5135 >        public final void compute() {
5136 >            final BiFun<? super V, ? super V, ? extends V> reducer;
5137 >            if ((reducer = this.reducer) != null) {
5138 >                for (int i = baseIndex, f, h; batch > 0 &&
5139 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5140 >                    addToPendingCount(1);
5141                      (rights = new ReduceValuesTask<K,V>
5142 <                     (this, b >>>= 1, rights, reducer)).fork();
5142 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5143 >                      rights, reducer)).fork();
5144                  }
5145                  V r = null;
5146 <                Object v;
5147 <                while ((v = advance()) != null) {
5148 <                    V u = (V)v;
5552 <                    r = (r == null) ? u : reducer.apply(r, u);
5146 >                for (Node<K,V> p; (p = advance()) != null; ) {
5147 >                    V v = p.val;
5148 >                    r = (r == null) ? v : reducer.apply(r, v);
5149                  }
5150                  result = r;
5151 <                for (ReduceValuesTask<K,V> t = this, s;;) {
5152 <                    int c; BulkTask<K,V,?> par; V tr, sr;
5153 <                    if ((c = t.pending) == 0) {
5154 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5155 <                            if ((sr = s.result) != null)
5156 <                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5157 <                        }
5158 <                        if ((par = t.parent) == null ||
5159 <                            !(par instanceof ReduceValuesTask)) {
5160 <                            t.quietlyComplete();
5161 <                            break;
5566 <                        }
5567 <                        t = (ReduceValuesTask<K,V>)par;
5151 >                CountedCompleter<?> c;
5152 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5153 >                    @SuppressWarnings("unchecked") ReduceValuesTask<K,V>
5154 >                        t = (ReduceValuesTask<K,V>)c,
5155 >                        s = t.rights;
5156 >                    while (s != null) {
5157 >                        V tr, sr;
5158 >                        if ((sr = s.result) != null)
5159 >                            t.result = (((tr = t.result) == null) ? sr :
5160 >                                        reducer.apply(tr, sr));
5161 >                        s = t.rights = s.nextRight;
5162                      }
5569                    else if (t.casPending(c, c - 1))
5570                        break;
5163                  }
5572            } catch (Throwable ex) {
5573                return tryCompleteComputation(ex);
5164              }
5575            return false;
5165          }
5577        public final V getRawResult() { return result; }
5166      }
5167  
5168 <    @SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
5168 >    @SuppressWarnings("serial")
5169 >    static final class ReduceEntriesTask<K,V>
5170          extends BulkTask<K,V,Map.Entry<K,V>> {
5171          final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5172          Map.Entry<K,V> result;
5173          ReduceEntriesTask<K,V> rights, nextRight;
5174          ReduceEntriesTask
5175 <            (ConcurrentHashMapV8<K,V> m,
5587 <             BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5588 <            super(m);
5589 <            this.reducer = reducer;
5590 <        }
5591 <        ReduceEntriesTask
5592 <            (BulkTask<K,V,?> p, int b,
5175 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5176               ReduceEntriesTask<K,V> nextRight,
5177 <             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5178 <            super(p, b); this.nextRight = nextRight;
5177 >             BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5178 >            super(p, b, i, f, t); this.nextRight = nextRight;
5179              this.reducer = reducer;
5180          }
5181 <
5182 <        @SuppressWarnings("unchecked") public final boolean exec() {
5183 <            final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer =
5184 <                this.reducer;
5185 <            if (reducer == null)
5186 <                return abortOnNullFunction();
5187 <            try {
5605 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5606 <                    do {} while (!casPending(c = pending, c+1));
5181 >        public final Map.Entry<K,V> getRawResult() { return result; }
5182 >        public final void compute() {
5183 >            final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5184 >            if ((reducer = this.reducer) != null) {
5185 >                for (int i = baseIndex, f, h; batch > 0 &&
5186 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5187 >                    addToPendingCount(1);
5188                      (rights = new ReduceEntriesTask<K,V>
5189 <                     (this, b >>>= 1, rights, reducer)).fork();
5189 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5190 >                      rights, reducer)).fork();
5191                  }
5192                  Map.Entry<K,V> r = null;
5193 <                Object v;
5194 <                while ((v = advance()) != null) {
5613 <                    Map.Entry<K,V> u = entryFor((K)nextKey, (V)v);
5614 <                    r = (r == null) ? u : reducer.apply(r, u);
5615 <                }
5193 >                for (Node<K,V> p; (p = advance()) != null; )
5194 >                    r = (r == null) ? p : reducer.apply(r, p);
5195                  result = r;
5196 <                for (ReduceEntriesTask<K,V> t = this, s;;) {
5197 <                    int c; BulkTask<K,V,?> par; Map.Entry<K,V> tr, sr;
5198 <                    if ((c = t.pending) == 0) {
5199 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5200 <                            if ((sr = s.result) != null)
5201 <                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5202 <                        }
5203 <                        if ((par = t.parent) == null ||
5204 <                            !(par instanceof ReduceEntriesTask)) {
5205 <                            t.quietlyComplete();
5206 <                            break;
5628 <                        }
5629 <                        t = (ReduceEntriesTask<K,V>)par;
5196 >                CountedCompleter<?> c;
5197 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5198 >                    @SuppressWarnings("unchecked") ReduceEntriesTask<K,V>
5199 >                        t = (ReduceEntriesTask<K,V>)c,
5200 >                        s = t.rights;
5201 >                    while (s != null) {
5202 >                        Map.Entry<K,V> tr, sr;
5203 >                        if ((sr = s.result) != null)
5204 >                            t.result = (((tr = t.result) == null) ? sr :
5205 >                                        reducer.apply(tr, sr));
5206 >                        s = t.rights = s.nextRight;
5207                      }
5631                    else if (t.casPending(c, c - 1))
5632                        break;
5208                  }
5634            } catch (Throwable ex) {
5635                return tryCompleteComputation(ex);
5209              }
5637            return false;
5210          }
5639        public final Map.Entry<K,V> getRawResult() { return result; }
5211      }
5212  
5213 <    @SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
5213 >    @SuppressWarnings("serial")
5214 >    static final class MapReduceKeysTask<K,V,U>
5215          extends BulkTask<K,V,U> {
5216          final Fun<? super K, ? extends U> transformer;
5217          final BiFun<? super U, ? super U, ? extends U> reducer;
5218          U result;
5219          MapReduceKeysTask<K,V,U> rights, nextRight;
5220          MapReduceKeysTask
5221 <            (ConcurrentHashMapV8<K,V> m,
5650 <             Fun<? super K, ? extends U> transformer,
5651 <             BiFun<? super U, ? super U, ? extends U> reducer) {
5652 <            super(m);
5653 <            this.transformer = transformer;
5654 <            this.reducer = reducer;
5655 <        }
5656 <        MapReduceKeysTask
5657 <            (BulkTask<K,V,?> p, int b,
5221 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5222               MapReduceKeysTask<K,V,U> nextRight,
5223               Fun<? super K, ? extends U> transformer,
5224               BiFun<? super U, ? super U, ? extends U> reducer) {
5225 <            super(p, b); this.nextRight = nextRight;
5225 >            super(p, b, i, f, t); this.nextRight = nextRight;
5226              this.transformer = transformer;
5227              this.reducer = reducer;
5228          }
5229 <        @SuppressWarnings("unchecked") public final boolean exec() {
5230 <            final Fun<? super K, ? extends U> transformer =
5231 <                this.transformer;
5232 <            final BiFun<? super U, ? super U, ? extends U> reducer =
5233 <                this.reducer;
5234 <            if (transformer == null || reducer == null)
5235 <                return abortOnNullFunction();
5236 <            try {
5237 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5674 <                    do {} while (!casPending(c = pending, c+1));
5229 >        public final U getRawResult() { return result; }
5230 >        public final void compute() {
5231 >            final Fun<? super K, ? extends U> transformer;
5232 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5233 >            if ((transformer = this.transformer) != null &&
5234 >                (reducer = this.reducer) != null) {
5235 >                for (int i = baseIndex, f, h; batch > 0 &&
5236 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5237 >                    addToPendingCount(1);
5238                      (rights = new MapReduceKeysTask<K,V,U>
5239 <                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5239 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5240 >                      rights, transformer, reducer)).fork();
5241                  }
5242 <                U r = null, u;
5243 <                while (advance() != null) {
5244 <                    if ((u = transformer.apply((K)nextKey)) != null)
5242 >                U r = null;
5243 >                for (Node<K,V> p; (p = advance()) != null; ) {
5244 >                    U u;
5245 >                    if ((u = transformer.apply(p.key)) != null)
5246                          r = (r == null) ? u : reducer.apply(r, u);
5247                  }
5248                  result = r;
5249 <                for (MapReduceKeysTask<K,V,U> t = this, s;;) {
5250 <                    int c; BulkTask<K,V,?> par; U tr, sr;
5251 <                    if ((c = t.pending) == 0) {
5252 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5253 <                            if ((sr = s.result) != null)
5254 <                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5255 <                        }
5256 <                        if ((par = t.parent) == null ||
5257 <                            !(par instanceof MapReduceKeysTask)) {
5258 <                            t.quietlyComplete();
5259 <                            break;
5695 <                        }
5696 <                        t = (MapReduceKeysTask<K,V,U>)par;
5249 >                CountedCompleter<?> c;
5250 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5251 >                    @SuppressWarnings("unchecked") MapReduceKeysTask<K,V,U>
5252 >                        t = (MapReduceKeysTask<K,V,U>)c,
5253 >                        s = t.rights;
5254 >                    while (s != null) {
5255 >                        U tr, sr;
5256 >                        if ((sr = s.result) != null)
5257 >                            t.result = (((tr = t.result) == null) ? sr :
5258 >                                        reducer.apply(tr, sr));
5259 >                        s = t.rights = s.nextRight;
5260                      }
5698                    else if (t.casPending(c, c - 1))
5699                        break;
5261                  }
5701            } catch (Throwable ex) {
5702                return tryCompleteComputation(ex);
5262              }
5704            return false;
5263          }
5706        public final U getRawResult() { return result; }
5264      }
5265  
5266 <    @SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
5266 >    @SuppressWarnings("serial")
5267 >    static final class MapReduceValuesTask<K,V,U>
5268          extends BulkTask<K,V,U> {
5269          final Fun<? super V, ? extends U> transformer;
5270          final BiFun<? super U, ? super U, ? extends U> reducer;
5271          U result;
5272          MapReduceValuesTask<K,V,U> rights, nextRight;
5273          MapReduceValuesTask
5274 <            (ConcurrentHashMapV8<K,V> m,
5717 <             Fun<? super V, ? extends U> transformer,
5718 <             BiFun<? super U, ? super U, ? extends U> reducer) {
5719 <            super(m);
5720 <            this.transformer = transformer;
5721 <            this.reducer = reducer;
5722 <        }
5723 <        MapReduceValuesTask
5724 <            (BulkTask<K,V,?> p, int b,
5274 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5275               MapReduceValuesTask<K,V,U> nextRight,
5276               Fun<? super V, ? extends U> transformer,
5277               BiFun<? super U, ? super U, ? extends U> reducer) {
5278 <            super(p, b); this.nextRight = nextRight;
5278 >            super(p, b, i, f, t); this.nextRight = nextRight;
5279              this.transformer = transformer;
5280              this.reducer = reducer;
5281          }
5282 <        @SuppressWarnings("unchecked") public final boolean exec() {
5283 <            final Fun<? super V, ? extends U> transformer =
5284 <                this.transformer;
5285 <            final BiFun<? super U, ? super U, ? extends U> reducer =
5286 <                this.reducer;
5287 <            if (transformer == null || reducer == null)
5288 <                return abortOnNullFunction();
5289 <            try {
5290 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5741 <                    do {} while (!casPending(c = pending, c+1));
5282 >        public final U getRawResult() { return result; }
5283 >        public final void compute() {
5284 >            final Fun<? super V, ? extends U> transformer;
5285 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5286 >            if ((transformer = this.transformer) != null &&
5287 >                (reducer = this.reducer) != null) {
5288 >                for (int i = baseIndex, f, h; batch > 0 &&
5289 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5290 >                    addToPendingCount(1);
5291                      (rights = new MapReduceValuesTask<K,V,U>
5292 <                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5292 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5293 >                      rights, transformer, reducer)).fork();
5294                  }
5295 <                U r = null, u;
5296 <                Object v;
5297 <                while ((v = advance()) != null) {
5298 <                    if ((u = transformer.apply((V)v)) != null)
5295 >                U r = null;
5296 >                for (Node<K,V> p; (p = advance()) != null; ) {
5297 >                    U u;
5298 >                    if ((u = transformer.apply(p.val)) != null)
5299                          r = (r == null) ? u : reducer.apply(r, u);
5300                  }
5301                  result = r;
5302 <                for (MapReduceValuesTask<K,V,U> t = this, s;;) {
5303 <                    int c; BulkTask<K,V,?> par; U tr, sr;
5304 <                    if ((c = t.pending) == 0) {
5305 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5306 <                            if ((sr = s.result) != null)
5307 <                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5308 <                        }
5309 <                        if ((par = t.parent) == null ||
5310 <                            !(par instanceof MapReduceValuesTask)) {
5311 <                            t.quietlyComplete();
5312 <                            break;
5763 <                        }
5764 <                        t = (MapReduceValuesTask<K,V,U>)par;
5302 >                CountedCompleter<?> c;
5303 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5304 >                    @SuppressWarnings("unchecked") MapReduceValuesTask<K,V,U>
5305 >                        t = (MapReduceValuesTask<K,V,U>)c,
5306 >                        s = t.rights;
5307 >                    while (s != null) {
5308 >                        U tr, sr;
5309 >                        if ((sr = s.result) != null)
5310 >                            t.result = (((tr = t.result) == null) ? sr :
5311 >                                        reducer.apply(tr, sr));
5312 >                        s = t.rights = s.nextRight;
5313                      }
5766                    else if (t.casPending(c, c - 1))
5767                        break;
5314                  }
5769            } catch (Throwable ex) {
5770                return tryCompleteComputation(ex);
5315              }
5772            return false;
5316          }
5774        public final U getRawResult() { return result; }
5317      }
5318  
5319 <    @SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
5319 >    @SuppressWarnings("serial")
5320 >    static final class MapReduceEntriesTask<K,V,U>
5321          extends BulkTask<K,V,U> {
5322          final Fun<Map.Entry<K,V>, ? extends U> transformer;
5323          final BiFun<? super U, ? super U, ? extends U> reducer;
5324          U result;
5325          MapReduceEntriesTask<K,V,U> rights, nextRight;
5326          MapReduceEntriesTask
5327 <            (ConcurrentHashMapV8<K,V> m,
5785 <             Fun<Map.Entry<K,V>, ? extends U> transformer,
5786 <             BiFun<? super U, ? super U, ? extends U> reducer) {
5787 <            super(m);
5788 <            this.transformer = transformer;
5789 <            this.reducer = reducer;
5790 <        }
5791 <        MapReduceEntriesTask
5792 <            (BulkTask<K,V,?> p, int b,
5327 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5328               MapReduceEntriesTask<K,V,U> nextRight,
5329               Fun<Map.Entry<K,V>, ? extends U> transformer,
5330               BiFun<? super U, ? super U, ? extends U> reducer) {
5331 <            super(p, b); this.nextRight = nextRight;
5331 >            super(p, b, i, f, t); this.nextRight = nextRight;
5332              this.transformer = transformer;
5333              this.reducer = reducer;
5334          }
5335 <        @SuppressWarnings("unchecked") public final boolean exec() {
5336 <            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5337 <                this.transformer;
5338 <            final BiFun<? super U, ? super U, ? extends U> reducer =
5339 <                this.reducer;
5340 <            if (transformer == null || reducer == null)
5341 <                return abortOnNullFunction();
5342 <            try {
5343 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5809 <                    do {} while (!casPending(c = pending, c+1));
5335 >        public final U getRawResult() { return result; }
5336 >        public final void compute() {
5337 >            final Fun<Map.Entry<K,V>, ? extends U> transformer;
5338 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5339 >            if ((transformer = this.transformer) != null &&
5340 >                (reducer = this.reducer) != null) {
5341 >                for (int i = baseIndex, f, h; batch > 0 &&
5342 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5343 >                    addToPendingCount(1);
5344                      (rights = new MapReduceEntriesTask<K,V,U>
5345 <                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5345 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5346 >                      rights, transformer, reducer)).fork();
5347                  }
5348 <                U r = null, u;
5349 <                Object v;
5350 <                while ((v = advance()) != null) {
5351 <                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5348 >                U r = null;
5349 >                for (Node<K,V> p; (p = advance()) != null; ) {
5350 >                    U u;
5351 >                    if ((u = transformer.apply(p)) != null)
5352                          r = (r == null) ? u : reducer.apply(r, u);
5353                  }
5354                  result = r;
5355 <                for (MapReduceEntriesTask<K,V,U> t = this, s;;) {
5356 <                    int c; BulkTask<K,V,?> par; U tr, sr;
5357 <                    if ((c = t.pending) == 0) {
5358 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5359 <                            if ((sr = s.result) != null)
5360 <                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5361 <                        }
5362 <                        if ((par = t.parent) == null ||
5363 <                            !(par instanceof MapReduceEntriesTask)) {
5364 <                            t.quietlyComplete();
5365 <                            break;
5831 <                        }
5832 <                        t = (MapReduceEntriesTask<K,V,U>)par;
5355 >                CountedCompleter<?> c;
5356 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5357 >                    @SuppressWarnings("unchecked") MapReduceEntriesTask<K,V,U>
5358 >                        t = (MapReduceEntriesTask<K,V,U>)c,
5359 >                        s = t.rights;
5360 >                    while (s != null) {
5361 >                        U tr, sr;
5362 >                        if ((sr = s.result) != null)
5363 >                            t.result = (((tr = t.result) == null) ? sr :
5364 >                                        reducer.apply(tr, sr));
5365 >                        s = t.rights = s.nextRight;
5366                      }
5834                    else if (t.casPending(c, c - 1))
5835                        break;
5367                  }
5837            } catch (Throwable ex) {
5838                return tryCompleteComputation(ex);
5368              }
5840            return false;
5369          }
5842        public final U getRawResult() { return result; }
5370      }
5371  
5372 <    @SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
5372 >    @SuppressWarnings("serial")
5373 >    static final class MapReduceMappingsTask<K,V,U>
5374          extends BulkTask<K,V,U> {
5375          final BiFun<? super K, ? super V, ? extends U> transformer;
5376          final BiFun<? super U, ? super U, ? extends U> reducer;
5377          U result;
5378          MapReduceMappingsTask<K,V,U> rights, nextRight;
5379          MapReduceMappingsTask
5380 <            (ConcurrentHashMapV8<K,V> m,
5853 <             BiFun<? super K, ? super V, ? extends U> transformer,
5854 <             BiFun<? super U, ? super U, ? extends U> reducer) {
5855 <            super(m);
5856 <            this.transformer = transformer;
5857 <            this.reducer = reducer;
5858 <        }
5859 <        MapReduceMappingsTask
5860 <            (BulkTask<K,V,?> p, int b,
5380 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5381               MapReduceMappingsTask<K,V,U> nextRight,
5382               BiFun<? super K, ? super V, ? extends U> transformer,
5383               BiFun<? super U, ? super U, ? extends U> reducer) {
5384 <            super(p, b); this.nextRight = nextRight;
5384 >            super(p, b, i, f, t); this.nextRight = nextRight;
5385              this.transformer = transformer;
5386              this.reducer = reducer;
5387          }
5388 <        @SuppressWarnings("unchecked") public final boolean exec() {
5389 <            final BiFun<? super K, ? super V, ? extends U> transformer =
5390 <                this.transformer;
5391 <            final BiFun<? super U, ? super U, ? extends U> reducer =
5392 <                this.reducer;
5393 <            if (transformer == null || reducer == null)
5394 <                return abortOnNullFunction();
5395 <            try {
5396 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5877 <                    do {} while (!casPending(c = pending, c+1));
5388 >        public final U getRawResult() { return result; }
5389 >        public final void compute() {
5390 >            final BiFun<? super K, ? super V, ? extends U> transformer;
5391 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5392 >            if ((transformer = this.transformer) != null &&
5393 >                (reducer = this.reducer) != null) {
5394 >                for (int i = baseIndex, f, h; batch > 0 &&
5395 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5396 >                    addToPendingCount(1);
5397                      (rights = new MapReduceMappingsTask<K,V,U>
5398 <                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5398 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5399 >                      rights, transformer, reducer)).fork();
5400                  }
5401 <                U r = null, u;
5402 <                Object v;
5403 <                while ((v = advance()) != null) {
5404 <                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5401 >                U r = null;
5402 >                for (Node<K,V> p; (p = advance()) != null; ) {
5403 >                    U u;
5404 >                    if ((u = transformer.apply(p.key, p.val)) != null)
5405                          r = (r == null) ? u : reducer.apply(r, u);
5406                  }
5407                  result = r;
5408 <                for (MapReduceMappingsTask<K,V,U> t = this, s;;) {
5409 <                    int c; BulkTask<K,V,?> par; U tr, sr;
5410 <                    if ((c = t.pending) == 0) {
5411 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5412 <                            if ((sr = s.result) != null)
5413 <                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5414 <                        }
5415 <                        if ((par = t.parent) == null ||
5416 <                            !(par instanceof MapReduceMappingsTask)) {
5417 <                            t.quietlyComplete();
5418 <                            break;
5899 <                        }
5900 <                        t = (MapReduceMappingsTask<K,V,U>)par;
5408 >                CountedCompleter<?> c;
5409 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5410 >                    @SuppressWarnings("unchecked") MapReduceMappingsTask<K,V,U>
5411 >                        t = (MapReduceMappingsTask<K,V,U>)c,
5412 >                        s = t.rights;
5413 >                    while (s != null) {
5414 >                        U tr, sr;
5415 >                        if ((sr = s.result) != null)
5416 >                            t.result = (((tr = t.result) == null) ? sr :
5417 >                                        reducer.apply(tr, sr));
5418 >                        s = t.rights = s.nextRight;
5419                      }
5902                    else if (t.casPending(c, c - 1))
5903                        break;
5420                  }
5905            } catch (Throwable ex) {
5906                return tryCompleteComputation(ex);
5421              }
5908            return false;
5422          }
5910        public final U getRawResult() { return result; }
5423      }
5424  
5425 <    @SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
5425 >    @SuppressWarnings("serial")
5426 >    static final class MapReduceKeysToDoubleTask<K,V>
5427          extends BulkTask<K,V,Double> {
5428          final ObjectToDouble<? super K> transformer;
5429          final DoubleByDoubleToDouble reducer;
# Line 5918 | Line 5431 | public class ConcurrentHashMapV8<K, V>
5431          double result;
5432          MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5433          MapReduceKeysToDoubleTask
5434 <            (ConcurrentHashMapV8<K,V> m,
5922 <             ObjectToDouble<? super K> transformer,
5923 <             double basis,
5924 <             DoubleByDoubleToDouble reducer) {
5925 <            super(m);
5926 <            this.transformer = transformer;
5927 <            this.basis = basis; this.reducer = reducer;
5928 <        }
5929 <        MapReduceKeysToDoubleTask
5930 <            (BulkTask<K,V,?> p, int b,
5434 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5435               MapReduceKeysToDoubleTask<K,V> nextRight,
5436               ObjectToDouble<? super K> transformer,
5437               double basis,
5438               DoubleByDoubleToDouble reducer) {
5439 <            super(p, b); this.nextRight = nextRight;
5439 >            super(p, b, i, f, t); this.nextRight = nextRight;
5440              this.transformer = transformer;
5441              this.basis = basis; this.reducer = reducer;
5442          }
5443 <        @SuppressWarnings("unchecked") public final boolean exec() {
5444 <            final ObjectToDouble<? super K> transformer =
5445 <                this.transformer;
5446 <            final DoubleByDoubleToDouble reducer = this.reducer;
5447 <            if (transformer == null || reducer == null)
5448 <                return abortOnNullFunction();
5449 <            try {
5450 <                final double id = this.basis;
5451 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5452 <                    do {} while (!casPending(c = pending, c+1));
5443 >        public final Double getRawResult() { return result; }
5444 >        public final void compute() {
5445 >            final ObjectToDouble<? super K> transformer;
5446 >            final DoubleByDoubleToDouble reducer;
5447 >            if ((transformer = this.transformer) != null &&
5448 >                (reducer = this.reducer) != null) {
5449 >                double r = this.basis;
5450 >                for (int i = baseIndex, f, h; batch > 0 &&
5451 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5452 >                    addToPendingCount(1);
5453                      (rights = new MapReduceKeysToDoubleTask<K,V>
5454 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5454 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5455 >                      rights, transformer, r, reducer)).fork();
5456                  }
5457 <                double r = id;
5458 <                while (advance() != null)
5954 <                    r = reducer.apply(r, transformer.apply((K)nextKey));
5457 >                for (Node<K,V> p; (p = advance()) != null; )
5458 >                    r = reducer.apply(r, transformer.apply(p.key));
5459                  result = r;
5460 <                for (MapReduceKeysToDoubleTask<K,V> t = this, s;;) {
5461 <                    int c; BulkTask<K,V,?> par;
5462 <                    if ((c = t.pending) == 0) {
5463 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5464 <                            t.result = reducer.apply(t.result, s.result);
5465 <                        }
5466 <                        if ((par = t.parent) == null ||
5467 <                            !(par instanceof MapReduceKeysToDoubleTask)) {
5964 <                            t.quietlyComplete();
5965 <                            break;
5966 <                        }
5967 <                        t = (MapReduceKeysToDoubleTask<K,V>)par;
5460 >                CountedCompleter<?> c;
5461 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5462 >                    @SuppressWarnings("unchecked") MapReduceKeysToDoubleTask<K,V>
5463 >                        t = (MapReduceKeysToDoubleTask<K,V>)c,
5464 >                        s = t.rights;
5465 >                    while (s != null) {
5466 >                        t.result = reducer.apply(t.result, s.result);
5467 >                        s = t.rights = s.nextRight;
5468                      }
5969                    else if (t.casPending(c, c - 1))
5970                        break;
5469                  }
5972            } catch (Throwable ex) {
5973                return tryCompleteComputation(ex);
5470              }
5975            return false;
5471          }
5977        public final Double getRawResult() { return result; }
5472      }
5473  
5474 <    @SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
5474 >    @SuppressWarnings("serial")
5475 >    static final class MapReduceValuesToDoubleTask<K,V>
5476          extends BulkTask<K,V,Double> {
5477          final ObjectToDouble<? super V> transformer;
5478          final DoubleByDoubleToDouble reducer;
# Line 5985 | Line 5480 | public class ConcurrentHashMapV8<K, V>
5480          double result;
5481          MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5482          MapReduceValuesToDoubleTask
5483 <            (ConcurrentHashMapV8<K,V> m,
5989 <             ObjectToDouble<? super V> transformer,
5990 <             double basis,
5991 <             DoubleByDoubleToDouble reducer) {
5992 <            super(m);
5993 <            this.transformer = transformer;
5994 <            this.basis = basis; this.reducer = reducer;
5995 <        }
5996 <        MapReduceValuesToDoubleTask
5997 <            (BulkTask<K,V,?> p, int b,
5483 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5484               MapReduceValuesToDoubleTask<K,V> nextRight,
5485               ObjectToDouble<? super V> transformer,
5486               double basis,
5487               DoubleByDoubleToDouble reducer) {
5488 <            super(p, b); this.nextRight = nextRight;
5488 >            super(p, b, i, f, t); this.nextRight = nextRight;
5489              this.transformer = transformer;
5490              this.basis = basis; this.reducer = reducer;
5491          }
5492 <        @SuppressWarnings("unchecked") public final boolean exec() {
5493 <            final ObjectToDouble<? super V> transformer =
5494 <                this.transformer;
5495 <            final DoubleByDoubleToDouble reducer = this.reducer;
5496 <            if (transformer == null || reducer == null)
5497 <                return abortOnNullFunction();
5498 <            try {
5499 <                final double id = this.basis;
5500 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5501 <                    do {} while (!casPending(c = pending, c+1));
5492 >        public final Double getRawResult() { return result; }
5493 >        public final void compute() {
5494 >            final ObjectToDouble<? super V> transformer;
5495 >            final DoubleByDoubleToDouble reducer;
5496 >            if ((transformer = this.transformer) != null &&
5497 >                (reducer = this.reducer) != null) {
5498 >                double r = this.basis;
5499 >                for (int i = baseIndex, f, h; batch > 0 &&
5500 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5501 >                    addToPendingCount(1);
5502                      (rights = new MapReduceValuesToDoubleTask<K,V>
5503 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5503 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5504 >                      rights, transformer, r, reducer)).fork();
5505                  }
5506 <                double r = id;
5507 <                Object v;
6021 <                while ((v = advance()) != null)
6022 <                    r = reducer.apply(r, transformer.apply((V)v));
5506 >                for (Node<K,V> p; (p = advance()) != null; )
5507 >                    r = reducer.apply(r, transformer.apply(p.val));
5508                  result = r;
5509 <                for (MapReduceValuesToDoubleTask<K,V> t = this, s;;) {
5510 <                    int c; BulkTask<K,V,?> par;
5511 <                    if ((c = t.pending) == 0) {
5512 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5513 <                            t.result = reducer.apply(t.result, s.result);
5514 <                        }
5515 <                        if ((par = t.parent) == null ||
5516 <                            !(par instanceof MapReduceValuesToDoubleTask)) {
6032 <                            t.quietlyComplete();
6033 <                            break;
6034 <                        }
6035 <                        t = (MapReduceValuesToDoubleTask<K,V>)par;
5509 >                CountedCompleter<?> c;
5510 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5511 >                    @SuppressWarnings("unchecked") MapReduceValuesToDoubleTask<K,V>
5512 >                        t = (MapReduceValuesToDoubleTask<K,V>)c,
5513 >                        s = t.rights;
5514 >                    while (s != null) {
5515 >                        t.result = reducer.apply(t.result, s.result);
5516 >                        s = t.rights = s.nextRight;
5517                      }
6037                    else if (t.casPending(c, c - 1))
6038                        break;
5518                  }
6040            } catch (Throwable ex) {
6041                return tryCompleteComputation(ex);
5519              }
6043            return false;
5520          }
6045        public final Double getRawResult() { return result; }
5521      }
5522  
5523 <    @SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
5523 >    @SuppressWarnings("serial")
5524 >    static final class MapReduceEntriesToDoubleTask<K,V>
5525          extends BulkTask<K,V,Double> {
5526          final ObjectToDouble<Map.Entry<K,V>> transformer;
5527          final DoubleByDoubleToDouble reducer;
# Line 6053 | Line 5529 | public class ConcurrentHashMapV8<K, V>
5529          double result;
5530          MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5531          MapReduceEntriesToDoubleTask
5532 <            (ConcurrentHashMapV8<K,V> m,
6057 <             ObjectToDouble<Map.Entry<K,V>> transformer,
6058 <             double basis,
6059 <             DoubleByDoubleToDouble reducer) {
6060 <            super(m);
6061 <            this.transformer = transformer;
6062 <            this.basis = basis; this.reducer = reducer;
6063 <        }
6064 <        MapReduceEntriesToDoubleTask
6065 <            (BulkTask<K,V,?> p, int b,
5532 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5533               MapReduceEntriesToDoubleTask<K,V> nextRight,
5534               ObjectToDouble<Map.Entry<K,V>> transformer,
5535               double basis,
5536               DoubleByDoubleToDouble reducer) {
5537 <            super(p, b); this.nextRight = nextRight;
5537 >            super(p, b, i, f, t); this.nextRight = nextRight;
5538              this.transformer = transformer;
5539              this.basis = basis; this.reducer = reducer;
5540          }
5541 <        @SuppressWarnings("unchecked") public final boolean exec() {
5542 <            final ObjectToDouble<Map.Entry<K,V>> transformer =
5543 <                this.transformer;
5544 <            final DoubleByDoubleToDouble reducer = this.reducer;
5545 <            if (transformer == null || reducer == null)
5546 <                return abortOnNullFunction();
5547 <            try {
5548 <                final double id = this.basis;
5549 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5550 <                    do {} while (!casPending(c = pending, c+1));
5541 >        public final Double getRawResult() { return result; }
5542 >        public final void compute() {
5543 >            final ObjectToDouble<Map.Entry<K,V>> transformer;
5544 >            final DoubleByDoubleToDouble reducer;
5545 >            if ((transformer = this.transformer) != null &&
5546 >                (reducer = this.reducer) != null) {
5547 >                double r = this.basis;
5548 >                for (int i = baseIndex, f, h; batch > 0 &&
5549 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5550 >                    addToPendingCount(1);
5551                      (rights = new MapReduceEntriesToDoubleTask<K,V>
5552 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5552 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5553 >                      rights, transformer, r, reducer)).fork();
5554                  }
5555 <                double r = id;
5556 <                Object v;
6089 <                while ((v = advance()) != null)
6090 <                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
5555 >                for (Node<K,V> p; (p = advance()) != null; )
5556 >                    r = reducer.apply(r, transformer.apply(p));
5557                  result = r;
5558 <                for (MapReduceEntriesToDoubleTask<K,V> t = this, s;;) {
5559 <                    int c; BulkTask<K,V,?> par;
5560 <                    if ((c = t.pending) == 0) {
5561 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5562 <                            t.result = reducer.apply(t.result, s.result);
5563 <                        }
5564 <                        if ((par = t.parent) == null ||
5565 <                            !(par instanceof MapReduceEntriesToDoubleTask)) {
6100 <                            t.quietlyComplete();
6101 <                            break;
6102 <                        }
6103 <                        t = (MapReduceEntriesToDoubleTask<K,V>)par;
5558 >                CountedCompleter<?> c;
5559 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5560 >                    @SuppressWarnings("unchecked") MapReduceEntriesToDoubleTask<K,V>
5561 >                        t = (MapReduceEntriesToDoubleTask<K,V>)c,
5562 >                        s = t.rights;
5563 >                    while (s != null) {
5564 >                        t.result = reducer.apply(t.result, s.result);
5565 >                        s = t.rights = s.nextRight;
5566                      }
6105                    else if (t.casPending(c, c - 1))
6106                        break;
5567                  }
6108            } catch (Throwable ex) {
6109                return tryCompleteComputation(ex);
5568              }
6111            return false;
5569          }
6113        public final Double getRawResult() { return result; }
5570      }
5571  
5572 <    @SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
5572 >    @SuppressWarnings("serial")
5573 >    static final class MapReduceMappingsToDoubleTask<K,V>
5574          extends BulkTask<K,V,Double> {
5575          final ObjectByObjectToDouble<? super K, ? super V> transformer;
5576          final DoubleByDoubleToDouble reducer;
# Line 6121 | Line 5578 | public class ConcurrentHashMapV8<K, V>
5578          double result;
5579          MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5580          MapReduceMappingsToDoubleTask
5581 <            (ConcurrentHashMapV8<K,V> m,
6125 <             ObjectByObjectToDouble<? super K, ? super V> transformer,
6126 <             double basis,
6127 <             DoubleByDoubleToDouble reducer) {
6128 <            super(m);
6129 <            this.transformer = transformer;
6130 <            this.basis = basis; this.reducer = reducer;
6131 <        }
6132 <        MapReduceMappingsToDoubleTask
6133 <            (BulkTask<K,V,?> p, int b,
5581 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5582               MapReduceMappingsToDoubleTask<K,V> nextRight,
5583               ObjectByObjectToDouble<? super K, ? super V> transformer,
5584               double basis,
5585               DoubleByDoubleToDouble reducer) {
5586 <            super(p, b); this.nextRight = nextRight;
5586 >            super(p, b, i, f, t); this.nextRight = nextRight;
5587              this.transformer = transformer;
5588              this.basis = basis; this.reducer = reducer;
5589          }
5590 <        @SuppressWarnings("unchecked") public final boolean exec() {
5591 <            final ObjectByObjectToDouble<? super K, ? super V> transformer =
5592 <                this.transformer;
5593 <            final DoubleByDoubleToDouble reducer = this.reducer;
5594 <            if (transformer == null || reducer == null)
5595 <                return abortOnNullFunction();
5596 <            try {
5597 <                final double id = this.basis;
5598 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5599 <                    do {} while (!casPending(c = pending, c+1));
5590 >        public final Double getRawResult() { return result; }
5591 >        public final void compute() {
5592 >            final ObjectByObjectToDouble<? super K, ? super V> transformer;
5593 >            final DoubleByDoubleToDouble reducer;
5594 >            if ((transformer = this.transformer) != null &&
5595 >                (reducer = this.reducer) != null) {
5596 >                double r = this.basis;
5597 >                for (int i = baseIndex, f, h; batch > 0 &&
5598 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5599 >                    addToPendingCount(1);
5600                      (rights = new MapReduceMappingsToDoubleTask<K,V>
5601 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5601 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5602 >                      rights, transformer, r, reducer)).fork();
5603                  }
5604 <                double r = id;
5605 <                Object v;
6157 <                while ((v = advance()) != null)
6158 <                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
5604 >                for (Node<K,V> p; (p = advance()) != null; )
5605 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5606                  result = r;
5607 <                for (MapReduceMappingsToDoubleTask<K,V> t = this, s;;) {
5608 <                    int c; BulkTask<K,V,?> par;
5609 <                    if ((c = t.pending) == 0) {
5610 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5611 <                            t.result = reducer.apply(t.result, s.result);
5612 <                        }
5613 <                        if ((par = t.parent) == null ||
5614 <                            !(par instanceof MapReduceMappingsToDoubleTask)) {
6168 <                            t.quietlyComplete();
6169 <                            break;
6170 <                        }
6171 <                        t = (MapReduceMappingsToDoubleTask<K,V>)par;
5607 >                CountedCompleter<?> c;
5608 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5609 >                    @SuppressWarnings("unchecked") MapReduceMappingsToDoubleTask<K,V>
5610 >                        t = (MapReduceMappingsToDoubleTask<K,V>)c,
5611 >                        s = t.rights;
5612 >                    while (s != null) {
5613 >                        t.result = reducer.apply(t.result, s.result);
5614 >                        s = t.rights = s.nextRight;
5615                      }
6173                    else if (t.casPending(c, c - 1))
6174                        break;
5616                  }
6176            } catch (Throwable ex) {
6177                return tryCompleteComputation(ex);
5617              }
6179            return false;
5618          }
6181        public final Double getRawResult() { return result; }
5619      }
5620  
5621 <    @SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
5621 >    @SuppressWarnings("serial")
5622 >    static final class MapReduceKeysToLongTask<K,V>
5623          extends BulkTask<K,V,Long> {
5624          final ObjectToLong<? super K> transformer;
5625          final LongByLongToLong reducer;
# Line 6189 | Line 5627 | public class ConcurrentHashMapV8<K, V>
5627          long result;
5628          MapReduceKeysToLongTask<K,V> rights, nextRight;
5629          MapReduceKeysToLongTask
5630 <            (ConcurrentHashMapV8<K,V> m,
6193 <             ObjectToLong<? super K> transformer,
6194 <             long basis,
6195 <             LongByLongToLong reducer) {
6196 <            super(m);
6197 <            this.transformer = transformer;
6198 <            this.basis = basis; this.reducer = reducer;
6199 <        }
6200 <        MapReduceKeysToLongTask
6201 <            (BulkTask<K,V,?> p, int b,
5630 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5631               MapReduceKeysToLongTask<K,V> nextRight,
5632               ObjectToLong<? super K> transformer,
5633               long basis,
5634               LongByLongToLong reducer) {
5635 <            super(p, b); this.nextRight = nextRight;
5635 >            super(p, b, i, f, t); this.nextRight = nextRight;
5636              this.transformer = transformer;
5637              this.basis = basis; this.reducer = reducer;
5638          }
5639 <        @SuppressWarnings("unchecked") public final boolean exec() {
5640 <            final ObjectToLong<? super K> transformer =
5641 <                this.transformer;
5642 <            final LongByLongToLong reducer = this.reducer;
5643 <            if (transformer == null || reducer == null)
5644 <                return abortOnNullFunction();
5645 <            try {
5646 <                final long id = this.basis;
5647 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5648 <                    do {} while (!casPending(c = pending, c+1));
5639 >        public final Long getRawResult() { return result; }
5640 >        public final void compute() {
5641 >            final ObjectToLong<? super K> transformer;
5642 >            final LongByLongToLong reducer;
5643 >            if ((transformer = this.transformer) != null &&
5644 >                (reducer = this.reducer) != null) {
5645 >                long r = this.basis;
5646 >                for (int i = baseIndex, f, h; batch > 0 &&
5647 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5648 >                    addToPendingCount(1);
5649                      (rights = new MapReduceKeysToLongTask<K,V>
5650 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5650 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5651 >                      rights, transformer, r, reducer)).fork();
5652                  }
5653 <                long r = id;
5654 <                while (advance() != null)
6225 <                    r = reducer.apply(r, transformer.apply((K)nextKey));
5653 >                for (Node<K,V> p; (p = advance()) != null; )
5654 >                    r = reducer.apply(r, transformer.apply(p.key));
5655                  result = r;
5656 <                for (MapReduceKeysToLongTask<K,V> t = this, s;;) {
5657 <                    int c; BulkTask<K,V,?> par;
5658 <                    if ((c = t.pending) == 0) {
5659 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5660 <                            t.result = reducer.apply(t.result, s.result);
5661 <                        }
5662 <                        if ((par = t.parent) == null ||
5663 <                            !(par instanceof MapReduceKeysToLongTask)) {
6235 <                            t.quietlyComplete();
6236 <                            break;
6237 <                        }
6238 <                        t = (MapReduceKeysToLongTask<K,V>)par;
5656 >                CountedCompleter<?> c;
5657 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5658 >                    @SuppressWarnings("unchecked") MapReduceKeysToLongTask<K,V>
5659 >                        t = (MapReduceKeysToLongTask<K,V>)c,
5660 >                        s = t.rights;
5661 >                    while (s != null) {
5662 >                        t.result = reducer.apply(t.result, s.result);
5663 >                        s = t.rights = s.nextRight;
5664                      }
6240                    else if (t.casPending(c, c - 1))
6241                        break;
5665                  }
6243            } catch (Throwable ex) {
6244                return tryCompleteComputation(ex);
5666              }
6246            return false;
5667          }
6248        public final Long getRawResult() { return result; }
5668      }
5669  
5670 <    @SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
5670 >    @SuppressWarnings("serial")
5671 >    static final class MapReduceValuesToLongTask<K,V>
5672          extends BulkTask<K,V,Long> {
5673          final ObjectToLong<? super V> transformer;
5674          final LongByLongToLong reducer;
# Line 6256 | Line 5676 | public class ConcurrentHashMapV8<K, V>
5676          long result;
5677          MapReduceValuesToLongTask<K,V> rights, nextRight;
5678          MapReduceValuesToLongTask
5679 <            (ConcurrentHashMapV8<K,V> m,
6260 <             ObjectToLong<? super V> transformer,
6261 <             long basis,
6262 <             LongByLongToLong reducer) {
6263 <            super(m);
6264 <            this.transformer = transformer;
6265 <            this.basis = basis; this.reducer = reducer;
6266 <        }
6267 <        MapReduceValuesToLongTask
6268 <            (BulkTask<K,V,?> p, int b,
5679 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5680               MapReduceValuesToLongTask<K,V> nextRight,
5681               ObjectToLong<? super V> transformer,
5682               long basis,
5683               LongByLongToLong reducer) {
5684 <            super(p, b); this.nextRight = nextRight;
5684 >            super(p, b, i, f, t); this.nextRight = nextRight;
5685              this.transformer = transformer;
5686              this.basis = basis; this.reducer = reducer;
5687          }
5688 <        @SuppressWarnings("unchecked") public final boolean exec() {
5689 <            final ObjectToLong<? super V> transformer =
5690 <                this.transformer;
5691 <            final LongByLongToLong reducer = this.reducer;
5692 <            if (transformer == null || reducer == null)
5693 <                return abortOnNullFunction();
5694 <            try {
5695 <                final long id = this.basis;
5696 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5697 <                    do {} while (!casPending(c = pending, c+1));
5688 >        public final Long getRawResult() { return result; }
5689 >        public final void compute() {
5690 >            final ObjectToLong<? super V> transformer;
5691 >            final LongByLongToLong reducer;
5692 >            if ((transformer = this.transformer) != null &&
5693 >                (reducer = this.reducer) != null) {
5694 >                long r = this.basis;
5695 >                for (int i = baseIndex, f, h; batch > 0 &&
5696 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5697 >                    addToPendingCount(1);
5698                      (rights = new MapReduceValuesToLongTask<K,V>
5699 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5699 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5700 >                      rights, transformer, r, reducer)).fork();
5701                  }
5702 <                long r = id;
5703 <                Object v;
6292 <                while ((v = advance()) != null)
6293 <                    r = reducer.apply(r, transformer.apply((V)v));
5702 >                for (Node<K,V> p; (p = advance()) != null; )
5703 >                    r = reducer.apply(r, transformer.apply(p.val));
5704                  result = r;
5705 <                for (MapReduceValuesToLongTask<K,V> t = this, s;;) {
5706 <                    int c; BulkTask<K,V,?> par;
5707 <                    if ((c = t.pending) == 0) {
5708 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5709 <                            t.result = reducer.apply(t.result, s.result);
5710 <                        }
5711 <                        if ((par = t.parent) == null ||
5712 <                            !(par instanceof MapReduceValuesToLongTask)) {
6303 <                            t.quietlyComplete();
6304 <                            break;
6305 <                        }
6306 <                        t = (MapReduceValuesToLongTask<K,V>)par;
5705 >                CountedCompleter<?> c;
5706 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5707 >                    @SuppressWarnings("unchecked") MapReduceValuesToLongTask<K,V>
5708 >                        t = (MapReduceValuesToLongTask<K,V>)c,
5709 >                        s = t.rights;
5710 >                    while (s != null) {
5711 >                        t.result = reducer.apply(t.result, s.result);
5712 >                        s = t.rights = s.nextRight;
5713                      }
6308                    else if (t.casPending(c, c - 1))
6309                        break;
5714                  }
6311            } catch (Throwable ex) {
6312                return tryCompleteComputation(ex);
5715              }
6314            return false;
5716          }
6316        public final Long getRawResult() { return result; }
5717      }
5718  
5719 <    @SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
5719 >    @SuppressWarnings("serial")
5720 >    static final class MapReduceEntriesToLongTask<K,V>
5721          extends BulkTask<K,V,Long> {
5722          final ObjectToLong<Map.Entry<K,V>> transformer;
5723          final LongByLongToLong reducer;
# Line 6324 | Line 5725 | public class ConcurrentHashMapV8<K, V>
5725          long result;
5726          MapReduceEntriesToLongTask<K,V> rights, nextRight;
5727          MapReduceEntriesToLongTask
5728 <            (ConcurrentHashMapV8<K,V> m,
6328 <             ObjectToLong<Map.Entry<K,V>> transformer,
6329 <             long basis,
6330 <             LongByLongToLong reducer) {
6331 <            super(m);
6332 <            this.transformer = transformer;
6333 <            this.basis = basis; this.reducer = reducer;
6334 <        }
6335 <        MapReduceEntriesToLongTask
6336 <            (BulkTask<K,V,?> p, int b,
5728 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5729               MapReduceEntriesToLongTask<K,V> nextRight,
5730               ObjectToLong<Map.Entry<K,V>> transformer,
5731               long basis,
5732               LongByLongToLong reducer) {
5733 <            super(p, b); this.nextRight = nextRight;
5733 >            super(p, b, i, f, t); this.nextRight = nextRight;
5734              this.transformer = transformer;
5735              this.basis = basis; this.reducer = reducer;
5736          }
5737 <        @SuppressWarnings("unchecked") public final boolean exec() {
5738 <            final ObjectToLong<Map.Entry<K,V>> transformer =
5739 <                this.transformer;
5740 <            final LongByLongToLong reducer = this.reducer;
5741 <            if (transformer == null || reducer == null)
5742 <                return abortOnNullFunction();
5743 <            try {
5744 <                final long id = this.basis;
5745 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5746 <                    do {} while (!casPending(c = pending, c+1));
5737 >        public final Long getRawResult() { return result; }
5738 >        public final void compute() {
5739 >            final ObjectToLong<Map.Entry<K,V>> transformer;
5740 >            final LongByLongToLong reducer;
5741 >            if ((transformer = this.transformer) != null &&
5742 >                (reducer = this.reducer) != null) {
5743 >                long r = this.basis;
5744 >                for (int i = baseIndex, f, h; batch > 0 &&
5745 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5746 >                    addToPendingCount(1);
5747                      (rights = new MapReduceEntriesToLongTask<K,V>
5748 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5748 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5749 >                      rights, transformer, r, reducer)).fork();
5750                  }
5751 <                long r = id;
5752 <                Object v;
6360 <                while ((v = advance()) != null)
6361 <                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
5751 >                for (Node<K,V> p; (p = advance()) != null; )
5752 >                    r = reducer.apply(r, transformer.apply(p));
5753                  result = r;
5754 <                for (MapReduceEntriesToLongTask<K,V> t = this, s;;) {
5755 <                    int c; BulkTask<K,V,?> par;
5756 <                    if ((c = t.pending) == 0) {
5757 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5758 <                            t.result = reducer.apply(t.result, s.result);
5759 <                        }
5760 <                        if ((par = t.parent) == null ||
5761 <                            !(par instanceof MapReduceEntriesToLongTask)) {
6371 <                            t.quietlyComplete();
6372 <                            break;
6373 <                        }
6374 <                        t = (MapReduceEntriesToLongTask<K,V>)par;
5754 >                CountedCompleter<?> c;
5755 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5756 >                    @SuppressWarnings("unchecked") MapReduceEntriesToLongTask<K,V>
5757 >                        t = (MapReduceEntriesToLongTask<K,V>)c,
5758 >                        s = t.rights;
5759 >                    while (s != null) {
5760 >                        t.result = reducer.apply(t.result, s.result);
5761 >                        s = t.rights = s.nextRight;
5762                      }
6376                    else if (t.casPending(c, c - 1))
6377                        break;
5763                  }
6379            } catch (Throwable ex) {
6380                return tryCompleteComputation(ex);
5764              }
6382            return false;
5765          }
6384        public final Long getRawResult() { return result; }
5766      }
5767  
5768 <    @SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
5768 >    @SuppressWarnings("serial")
5769 >    static final class MapReduceMappingsToLongTask<K,V>
5770          extends BulkTask<K,V,Long> {
5771          final ObjectByObjectToLong<? super K, ? super V> transformer;
5772          final LongByLongToLong reducer;
# Line 6392 | Line 5774 | public class ConcurrentHashMapV8<K, V>
5774          long result;
5775          MapReduceMappingsToLongTask<K,V> rights, nextRight;
5776          MapReduceMappingsToLongTask
5777 <            (ConcurrentHashMapV8<K,V> m,
6396 <             ObjectByObjectToLong<? super K, ? super V> transformer,
6397 <             long basis,
6398 <             LongByLongToLong reducer) {
6399 <            super(m);
6400 <            this.transformer = transformer;
6401 <            this.basis = basis; this.reducer = reducer;
6402 <        }
6403 <        MapReduceMappingsToLongTask
6404 <            (BulkTask<K,V,?> p, int b,
5777 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5778               MapReduceMappingsToLongTask<K,V> nextRight,
5779               ObjectByObjectToLong<? super K, ? super V> transformer,
5780               long basis,
5781               LongByLongToLong reducer) {
5782 <            super(p, b); this.nextRight = nextRight;
5782 >            super(p, b, i, f, t); this.nextRight = nextRight;
5783              this.transformer = transformer;
5784              this.basis = basis; this.reducer = reducer;
5785          }
5786 <        @SuppressWarnings("unchecked") public final boolean exec() {
5787 <            final ObjectByObjectToLong<? super K, ? super V> transformer =
5788 <                this.transformer;
5789 <            final LongByLongToLong reducer = this.reducer;
5790 <            if (transformer == null || reducer == null)
5791 <                return abortOnNullFunction();
5792 <            try {
5793 <                final long id = this.basis;
5794 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5795 <                    do {} while (!casPending(c = pending, c+1));
5786 >        public final Long getRawResult() { return result; }
5787 >        public final void compute() {
5788 >            final ObjectByObjectToLong<? super K, ? super V> transformer;
5789 >            final LongByLongToLong reducer;
5790 >            if ((transformer = this.transformer) != null &&
5791 >                (reducer = this.reducer) != null) {
5792 >                long r = this.basis;
5793 >                for (int i = baseIndex, f, h; batch > 0 &&
5794 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5795 >                    addToPendingCount(1);
5796                      (rights = new MapReduceMappingsToLongTask<K,V>
5797 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5797 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5798 >                      rights, transformer, r, reducer)).fork();
5799                  }
5800 <                long r = id;
5801 <                Object v;
6428 <                while ((v = advance()) != null)
6429 <                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
5800 >                for (Node<K,V> p; (p = advance()) != null; )
5801 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5802                  result = r;
5803 <                for (MapReduceMappingsToLongTask<K,V> t = this, s;;) {
5804 <                    int c; BulkTask<K,V,?> par;
5805 <                    if ((c = t.pending) == 0) {
5806 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5807 <                            t.result = reducer.apply(t.result, s.result);
5808 <                        }
5809 <                        if ((par = t.parent) == null ||
5810 <                            !(par instanceof MapReduceMappingsToLongTask)) {
6439 <                            t.quietlyComplete();
6440 <                            break;
6441 <                        }
6442 <                        t = (MapReduceMappingsToLongTask<K,V>)par;
5803 >                CountedCompleter<?> c;
5804 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5805 >                    @SuppressWarnings("unchecked") MapReduceMappingsToLongTask<K,V>
5806 >                        t = (MapReduceMappingsToLongTask<K,V>)c,
5807 >                        s = t.rights;
5808 >                    while (s != null) {
5809 >                        t.result = reducer.apply(t.result, s.result);
5810 >                        s = t.rights = s.nextRight;
5811                      }
6444                    else if (t.casPending(c, c - 1))
6445                        break;
5812                  }
6447            } catch (Throwable ex) {
6448                return tryCompleteComputation(ex);
5813              }
6450            return false;
5814          }
6452        public final Long getRawResult() { return result; }
5815      }
5816  
5817 <    @SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
5817 >    @SuppressWarnings("serial")
5818 >    static final class MapReduceKeysToIntTask<K,V>
5819          extends BulkTask<K,V,Integer> {
5820          final ObjectToInt<? super K> transformer;
5821          final IntByIntToInt reducer;
# Line 6460 | Line 5823 | public class ConcurrentHashMapV8<K, V>
5823          int result;
5824          MapReduceKeysToIntTask<K,V> rights, nextRight;
5825          MapReduceKeysToIntTask
5826 <            (ConcurrentHashMapV8<K,V> m,
6464 <             ObjectToInt<? super K> transformer,
6465 <             int basis,
6466 <             IntByIntToInt reducer) {
6467 <            super(m);
6468 <            this.transformer = transformer;
6469 <            this.basis = basis; this.reducer = reducer;
6470 <        }
6471 <        MapReduceKeysToIntTask
6472 <            (BulkTask<K,V,?> p, int b,
5826 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5827               MapReduceKeysToIntTask<K,V> nextRight,
5828               ObjectToInt<? super K> transformer,
5829               int basis,
5830               IntByIntToInt reducer) {
5831 <            super(p, b); this.nextRight = nextRight;
5831 >            super(p, b, i, f, t); this.nextRight = nextRight;
5832              this.transformer = transformer;
5833              this.basis = basis; this.reducer = reducer;
5834          }
5835 <        @SuppressWarnings("unchecked") public final boolean exec() {
5836 <            final ObjectToInt<? super K> transformer =
5837 <                this.transformer;
5838 <            final IntByIntToInt reducer = this.reducer;
5839 <            if (transformer == null || reducer == null)
5840 <                return abortOnNullFunction();
5841 <            try {
5842 <                final int id = this.basis;
5843 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5844 <                    do {} while (!casPending(c = pending, c+1));
5835 >        public final Integer getRawResult() { return result; }
5836 >        public final void compute() {
5837 >            final ObjectToInt<? super K> transformer;
5838 >            final IntByIntToInt reducer;
5839 >            if ((transformer = this.transformer) != null &&
5840 >                (reducer = this.reducer) != null) {
5841 >                int r = this.basis;
5842 >                for (int i = baseIndex, f, h; batch > 0 &&
5843 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5844 >                    addToPendingCount(1);
5845                      (rights = new MapReduceKeysToIntTask<K,V>
5846 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5846 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5847 >                      rights, transformer, r, reducer)).fork();
5848                  }
5849 <                int r = id;
5850 <                while (advance() != null)
6496 <                    r = reducer.apply(r, transformer.apply((K)nextKey));
5849 >                for (Node<K,V> p; (p = advance()) != null; )
5850 >                    r = reducer.apply(r, transformer.apply(p.key));
5851                  result = r;
5852 <                for (MapReduceKeysToIntTask<K,V> t = this, s;;) {
5853 <                    int c; BulkTask<K,V,?> par;
5854 <                    if ((c = t.pending) == 0) {
5855 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5856 <                            t.result = reducer.apply(t.result, s.result);
5857 <                        }
5858 <                        if ((par = t.parent) == null ||
5859 <                            !(par instanceof MapReduceKeysToIntTask)) {
6506 <                            t.quietlyComplete();
6507 <                            break;
6508 <                        }
6509 <                        t = (MapReduceKeysToIntTask<K,V>)par;
5852 >                CountedCompleter<?> c;
5853 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5854 >                    @SuppressWarnings("unchecked") MapReduceKeysToIntTask<K,V>
5855 >                        t = (MapReduceKeysToIntTask<K,V>)c,
5856 >                        s = t.rights;
5857 >                    while (s != null) {
5858 >                        t.result = reducer.apply(t.result, s.result);
5859 >                        s = t.rights = s.nextRight;
5860                      }
6511                    else if (t.casPending(c, c - 1))
6512                        break;
5861                  }
6514            } catch (Throwable ex) {
6515                return tryCompleteComputation(ex);
5862              }
6517            return false;
5863          }
6519        public final Integer getRawResult() { return result; }
5864      }
5865  
5866 <    @SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
5866 >    @SuppressWarnings("serial")
5867 >    static final class MapReduceValuesToIntTask<K,V>
5868          extends BulkTask<K,V,Integer> {
5869          final ObjectToInt<? super V> transformer;
5870          final IntByIntToInt reducer;
# Line 6527 | Line 5872 | public class ConcurrentHashMapV8<K, V>
5872          int result;
5873          MapReduceValuesToIntTask<K,V> rights, nextRight;
5874          MapReduceValuesToIntTask
5875 <            (ConcurrentHashMapV8<K,V> m,
6531 <             ObjectToInt<? super V> transformer,
6532 <             int basis,
6533 <             IntByIntToInt reducer) {
6534 <            super(m);
6535 <            this.transformer = transformer;
6536 <            this.basis = basis; this.reducer = reducer;
6537 <        }
6538 <        MapReduceValuesToIntTask
6539 <            (BulkTask<K,V,?> p, int b,
5875 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5876               MapReduceValuesToIntTask<K,V> nextRight,
5877               ObjectToInt<? super V> transformer,
5878               int basis,
5879               IntByIntToInt reducer) {
5880 <            super(p, b); this.nextRight = nextRight;
5880 >            super(p, b, i, f, t); this.nextRight = nextRight;
5881              this.transformer = transformer;
5882              this.basis = basis; this.reducer = reducer;
5883          }
5884 <        @SuppressWarnings("unchecked") public final boolean exec() {
5885 <            final ObjectToInt<? super V> transformer =
5886 <                this.transformer;
5887 <            final IntByIntToInt reducer = this.reducer;
5888 <            if (transformer == null || reducer == null)
5889 <                return abortOnNullFunction();
5890 <            try {
5891 <                final int id = this.basis;
5892 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5893 <                    do {} while (!casPending(c = pending, c+1));
5884 >        public final Integer getRawResult() { return result; }
5885 >        public final void compute() {
5886 >            final ObjectToInt<? super V> transformer;
5887 >            final IntByIntToInt reducer;
5888 >            if ((transformer = this.transformer) != null &&
5889 >                (reducer = this.reducer) != null) {
5890 >                int r = this.basis;
5891 >                for (int i = baseIndex, f, h; batch > 0 &&
5892 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5893 >                    addToPendingCount(1);
5894                      (rights = new MapReduceValuesToIntTask<K,V>
5895 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5895 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5896 >                      rights, transformer, r, reducer)).fork();
5897                  }
5898 <                int r = id;
5899 <                Object v;
6563 <                while ((v = advance()) != null)
6564 <                    r = reducer.apply(r, transformer.apply((V)v));
5898 >                for (Node<K,V> p; (p = advance()) != null; )
5899 >                    r = reducer.apply(r, transformer.apply(p.val));
5900                  result = r;
5901 <                for (MapReduceValuesToIntTask<K,V> t = this, s;;) {
5902 <                    int c; BulkTask<K,V,?> par;
5903 <                    if ((c = t.pending) == 0) {
5904 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5905 <                            t.result = reducer.apply(t.result, s.result);
5906 <                        }
5907 <                        if ((par = t.parent) == null ||
5908 <                            !(par instanceof MapReduceValuesToIntTask)) {
6574 <                            t.quietlyComplete();
6575 <                            break;
6576 <                        }
6577 <                        t = (MapReduceValuesToIntTask<K,V>)par;
5901 >                CountedCompleter<?> c;
5902 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5903 >                    @SuppressWarnings("unchecked") MapReduceValuesToIntTask<K,V>
5904 >                        t = (MapReduceValuesToIntTask<K,V>)c,
5905 >                        s = t.rights;
5906 >                    while (s != null) {
5907 >                        t.result = reducer.apply(t.result, s.result);
5908 >                        s = t.rights = s.nextRight;
5909                      }
6579                    else if (t.casPending(c, c - 1))
6580                        break;
5910                  }
6582            } catch (Throwable ex) {
6583                return tryCompleteComputation(ex);
5911              }
6585            return false;
5912          }
6587        public final Integer getRawResult() { return result; }
5913      }
5914  
5915 <    @SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
5915 >    @SuppressWarnings("serial")
5916 >    static final class MapReduceEntriesToIntTask<K,V>
5917          extends BulkTask<K,V,Integer> {
5918          final ObjectToInt<Map.Entry<K,V>> transformer;
5919          final IntByIntToInt reducer;
# Line 6595 | Line 5921 | public class ConcurrentHashMapV8<K, V>
5921          int result;
5922          MapReduceEntriesToIntTask<K,V> rights, nextRight;
5923          MapReduceEntriesToIntTask
5924 <            (ConcurrentHashMapV8<K,V> m,
6599 <             ObjectToInt<Map.Entry<K,V>> transformer,
6600 <             int basis,
6601 <             IntByIntToInt reducer) {
6602 <            super(m);
6603 <            this.transformer = transformer;
6604 <            this.basis = basis; this.reducer = reducer;
6605 <        }
6606 <        MapReduceEntriesToIntTask
6607 <            (BulkTask<K,V,?> p, int b,
5924 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5925               MapReduceEntriesToIntTask<K,V> nextRight,
5926               ObjectToInt<Map.Entry<K,V>> transformer,
5927               int basis,
5928               IntByIntToInt reducer) {
5929 <            super(p, b); this.nextRight = nextRight;
5929 >            super(p, b, i, f, t); this.nextRight = nextRight;
5930              this.transformer = transformer;
5931              this.basis = basis; this.reducer = reducer;
5932          }
5933 <        @SuppressWarnings("unchecked") public final boolean exec() {
5934 <            final ObjectToInt<Map.Entry<K,V>> transformer =
5935 <                this.transformer;
5936 <            final IntByIntToInt reducer = this.reducer;
5937 <            if (transformer == null || reducer == null)
5938 <                return abortOnNullFunction();
5939 <            try {
5940 <                final int id = this.basis;
5941 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5942 <                    do {} while (!casPending(c = pending, c+1));
5933 >        public final Integer getRawResult() { return result; }
5934 >        public final void compute() {
5935 >            final ObjectToInt<Map.Entry<K,V>> transformer;
5936 >            final IntByIntToInt reducer;
5937 >            if ((transformer = this.transformer) != null &&
5938 >                (reducer = this.reducer) != null) {
5939 >                int r = this.basis;
5940 >                for (int i = baseIndex, f, h; batch > 0 &&
5941 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5942 >                    addToPendingCount(1);
5943                      (rights = new MapReduceEntriesToIntTask<K,V>
5944 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5944 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5945 >                      rights, transformer, r, reducer)).fork();
5946                  }
5947 <                int r = id;
5948 <                Object v;
6631 <                while ((v = advance()) != null)
6632 <                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
5947 >                for (Node<K,V> p; (p = advance()) != null; )
5948 >                    r = reducer.apply(r, transformer.apply(p));
5949                  result = r;
5950 <                for (MapReduceEntriesToIntTask<K,V> t = this, s;;) {
5951 <                    int c; BulkTask<K,V,?> par;
5952 <                    if ((c = t.pending) == 0) {
5953 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5954 <                            t.result = reducer.apply(t.result, s.result);
5955 <                        }
5956 <                        if ((par = t.parent) == null ||
5957 <                            !(par instanceof MapReduceEntriesToIntTask)) {
6642 <                            t.quietlyComplete();
6643 <                            break;
6644 <                        }
6645 <                        t = (MapReduceEntriesToIntTask<K,V>)par;
5950 >                CountedCompleter<?> c;
5951 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5952 >                    @SuppressWarnings("unchecked") MapReduceEntriesToIntTask<K,V>
5953 >                        t = (MapReduceEntriesToIntTask<K,V>)c,
5954 >                        s = t.rights;
5955 >                    while (s != null) {
5956 >                        t.result = reducer.apply(t.result, s.result);
5957 >                        s = t.rights = s.nextRight;
5958                      }
6647                    else if (t.casPending(c, c - 1))
6648                        break;
5959                  }
6650            } catch (Throwable ex) {
6651                return tryCompleteComputation(ex);
5960              }
6653            return false;
5961          }
6655        public final Integer getRawResult() { return result; }
5962      }
5963  
5964 <    @SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
5964 >    @SuppressWarnings("serial")
5965 >    static final class MapReduceMappingsToIntTask<K,V>
5966          extends BulkTask<K,V,Integer> {
5967          final ObjectByObjectToInt<? super K, ? super V> transformer;
5968          final IntByIntToInt reducer;
# Line 6663 | Line 5970 | public class ConcurrentHashMapV8<K, V>
5970          int result;
5971          MapReduceMappingsToIntTask<K,V> rights, nextRight;
5972          MapReduceMappingsToIntTask
5973 <            (ConcurrentHashMapV8<K,V> m,
6667 <             ObjectByObjectToInt<? super K, ? super V> transformer,
6668 <             int basis,
6669 <             IntByIntToInt reducer) {
6670 <            super(m);
6671 <            this.transformer = transformer;
6672 <            this.basis = basis; this.reducer = reducer;
6673 <        }
6674 <        MapReduceMappingsToIntTask
6675 <            (BulkTask<K,V,?> p, int b,
5973 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5974               MapReduceMappingsToIntTask<K,V> nextRight,
5975               ObjectByObjectToInt<? super K, ? super V> transformer,
5976               int basis,
5977               IntByIntToInt reducer) {
5978 <            super(p, b); this.nextRight = nextRight;
5978 >            super(p, b, i, f, t); this.nextRight = nextRight;
5979              this.transformer = transformer;
5980              this.basis = basis; this.reducer = reducer;
5981          }
5982 <        @SuppressWarnings("unchecked") public final boolean exec() {
5983 <            final ObjectByObjectToInt<? super K, ? super V> transformer =
5984 <                this.transformer;
5985 <            final IntByIntToInt reducer = this.reducer;
5986 <            if (transformer == null || reducer == null)
5987 <                return abortOnNullFunction();
5988 <            try {
5989 <                final int id = this.basis;
5990 <                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5991 <                    do {} while (!casPending(c = pending, c+1));
5982 >        public final Integer getRawResult() { return result; }
5983 >        public final void compute() {
5984 >            final ObjectByObjectToInt<? super K, ? super V> transformer;
5985 >            final IntByIntToInt reducer;
5986 >            if ((transformer = this.transformer) != null &&
5987 >                (reducer = this.reducer) != null) {
5988 >                int r = this.basis;
5989 >                for (int i = baseIndex, f, h; batch > 0 &&
5990 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5991 >                    addToPendingCount(1);
5992                      (rights = new MapReduceMappingsToIntTask<K,V>
5993 <                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5993 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5994 >                      rights, transformer, r, reducer)).fork();
5995                  }
5996 <                int r = id;
5997 <                Object v;
6699 <                while ((v = advance()) != null)
6700 <                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
5996 >                for (Node<K,V> p; (p = advance()) != null; )
5997 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5998                  result = r;
5999 <                for (MapReduceMappingsToIntTask<K,V> t = this, s;;) {
6000 <                    int c; BulkTask<K,V,?> par;
6001 <                    if ((c = t.pending) == 0) {
6002 <                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6003 <                            t.result = reducer.apply(t.result, s.result);
5999 >                CountedCompleter<?> c;
6000 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
6001 >                    @SuppressWarnings("unchecked") MapReduceMappingsToIntTask<K,V>
6002 >                        t = (MapReduceMappingsToIntTask<K,V>)c,
6003 >                        s = t.rights;
6004 >                    while (s != null) {
6005 >                        t.result = reducer.apply(t.result, s.result);
6006 >                        s = t.rights = s.nextRight;
6007 >                    }
6008 >                }
6009 >            }
6010 >        }
6011 >    }
6012 >
6013 >    /* ---------------- Counters -------------- */
6014 >
6015 >    // Adapted from LongAdder and Striped64.
6016 >    // See their internal docs for explanation.
6017 >
6018 >    // A padded cell for distributing counts
6019 >    static final class CounterCell {
6020 >        volatile long p0, p1, p2, p3, p4, p5, p6;
6021 >        volatile long value;
6022 >        volatile long q0, q1, q2, q3, q4, q5, q6;
6023 >        CounterCell(long x) { value = x; }
6024 >    }
6025 >
6026 >    /**
6027 >     * Holder for the thread-local hash code determining which
6028 >     * CounterCell to use. The code is initialized via the
6029 >     * counterHashCodeGenerator, but may be moved upon collisions.
6030 >     */
6031 >    static final class CounterHashCode {
6032 >        int code;
6033 >    }
6034 >
6035 >    /**
6036 >     * Generates initial value for per-thread CounterHashCodes.
6037 >     */
6038 >    static final AtomicInteger counterHashCodeGenerator = new AtomicInteger();
6039 >
6040 >    /**
6041 >     * Increment for counterHashCodeGenerator. See class ThreadLocal
6042 >     * for explanation.
6043 >     */
6044 >    static final int SEED_INCREMENT = 0x61c88647;
6045 >
6046 >    /**
6047 >     * Per-thread counter hash codes. Shared across all instances.
6048 >     */
6049 >    static final ThreadLocal<CounterHashCode> threadCounterHashCode =
6050 >        new ThreadLocal<CounterHashCode>();
6051 >
6052 >
6053 >    final long sumCount() {
6054 >        CounterCell[] as = counterCells; CounterCell a;
6055 >        long sum = baseCount;
6056 >        if (as != null) {
6057 >            for (int i = 0; i < as.length; ++i) {
6058 >                if ((a = as[i]) != null)
6059 >                    sum += a.value;
6060 >            }
6061 >        }
6062 >        return sum;
6063 >    }
6064 >
6065 >    // See LongAdder version for explanation
6066 >    private final void fullAddCount(long x, CounterHashCode hc,
6067 >                                    boolean wasUncontended) {
6068 >        int h;
6069 >        if (hc == null) {
6070 >            hc = new CounterHashCode();
6071 >            int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT);
6072 >            h = hc.code = (s == 0) ? 1 : s; // Avoid zero
6073 >            threadCounterHashCode.set(hc);
6074 >        }
6075 >        else
6076 >            h = hc.code;
6077 >        boolean collide = false;                // True if last slot nonempty
6078 >        for (;;) {
6079 >            CounterCell[] as; CounterCell a; int n; long v;
6080 >            if ((as = counterCells) != null && (n = as.length) > 0) {
6081 >                if ((a = as[(n - 1) & h]) == null) {
6082 >                    if (cellsBusy == 0) {            // Try to attach new Cell
6083 >                        CounterCell r = new CounterCell(x); // Optimistic create
6084 >                        if (cellsBusy == 0 &&
6085 >                            U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
6086 >                            boolean created = false;
6087 >                            try {               // Recheck under lock
6088 >                                CounterCell[] rs; int m, j;
6089 >                                if ((rs = counterCells) != null &&
6090 >                                    (m = rs.length) > 0 &&
6091 >                                    rs[j = (m - 1) & h] == null) {
6092 >                                    rs[j] = r;
6093 >                                    created = true;
6094 >                                }
6095 >                            } finally {
6096 >                                cellsBusy = 0;
6097 >                            }
6098 >                            if (created)
6099 >                                break;
6100 >                            continue;           // Slot is now non-empty
6101                          }
6102 <                        if ((par = t.parent) == null ||
6103 <                            !(par instanceof MapReduceMappingsToIntTask)) {
6104 <                            t.quietlyComplete();
6105 <                            break;
6102 >                    }
6103 >                    collide = false;
6104 >                }
6105 >                else if (!wasUncontended)       // CAS already known to fail
6106 >                    wasUncontended = true;      // Continue after rehash
6107 >                else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
6108 >                    break;
6109 >                else if (counterCells != as || n >= NCPU)
6110 >                    collide = false;            // At max size or stale
6111 >                else if (!collide)
6112 >                    collide = true;
6113 >                else if (cellsBusy == 0 &&
6114 >                         U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
6115 >                    try {
6116 >                        if (counterCells == as) {// Expand table unless stale
6117 >                            CounterCell[] rs = new CounterCell[n << 1];
6118 >                            for (int i = 0; i < n; ++i)
6119 >                                rs[i] = as[i];
6120 >                            counterCells = rs;
6121                          }
6122 <                        t = (MapReduceMappingsToIntTask<K,V>)par;
6122 >                    } finally {
6123 >                        cellsBusy = 0;
6124                      }
6125 <                    else if (t.casPending(c, c - 1))
6126 <                        break;
6125 >                    collide = false;
6126 >                    continue;                   // Retry with expanded table
6127                  }
6128 <            } catch (Throwable ex) {
6129 <                return tryCompleteComputation(ex);
6128 >                h ^= h << 13;                   // Rehash
6129 >                h ^= h >>> 17;
6130 >                h ^= h << 5;
6131 >            }
6132 >            else if (cellsBusy == 0 && counterCells == as &&
6133 >                     U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
6134 >                boolean init = false;
6135 >                try {                           // Initialize table
6136 >                    if (counterCells == as) {
6137 >                        CounterCell[] rs = new CounterCell[2];
6138 >                        rs[h & 1] = new CounterCell(x);
6139 >                        counterCells = rs;
6140 >                        init = true;
6141 >                    }
6142 >                } finally {
6143 >                    cellsBusy = 0;
6144 >                }
6145 >                if (init)
6146 >                    break;
6147              }
6148 <            return false;
6148 >            else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
6149 >                break;                          // Fall back on using base
6150          }
6151 <        public final Integer getRawResult() { return result; }
6151 >        hc.code = h;                            // Record index for next time
6152      }
6153  
6726
6154      // Unsafe mechanics
6155 <    private static final sun.misc.Unsafe UNSAFE;
6156 <    private static final long counterOffset;
6157 <    private static final long sizeCtlOffset;
6155 >    private static final sun.misc.Unsafe U;
6156 >    private static final long SIZECTL;
6157 >    private static final long TRANSFERINDEX;
6158 >    private static final long TRANSFERORIGIN;
6159 >    private static final long BASECOUNT;
6160 >    private static final long CELLSBUSY;
6161 >    private static final long CELLVALUE;
6162      private static final long ABASE;
6163      private static final int ASHIFT;
6164  
6165      static {
6735        int ss;
6166          try {
6167 <            UNSAFE = getUnsafe();
6167 >            U = getUnsafe();
6168              Class<?> k = ConcurrentHashMapV8.class;
6169 <            counterOffset = UNSAFE.objectFieldOffset
6740 <                (k.getDeclaredField("counter"));
6741 <            sizeCtlOffset = UNSAFE.objectFieldOffset
6169 >            SIZECTL = U.objectFieldOffset
6170                  (k.getDeclaredField("sizeCtl"));
6171 <            Class<?> sc = Node[].class;
6172 <            ABASE = UNSAFE.arrayBaseOffset(sc);
6173 <            ss = UNSAFE.arrayIndexScale(sc);
6171 >            TRANSFERINDEX = U.objectFieldOffset
6172 >                (k.getDeclaredField("transferIndex"));
6173 >            TRANSFERORIGIN = U.objectFieldOffset
6174 >                (k.getDeclaredField("transferOrigin"));
6175 >            BASECOUNT = U.objectFieldOffset
6176 >                (k.getDeclaredField("baseCount"));
6177 >            CELLSBUSY = U.objectFieldOffset
6178 >                (k.getDeclaredField("cellsBusy"));
6179 >            Class<?> ck = CounterCell.class;
6180 >            CELLVALUE = U.objectFieldOffset
6181 >                (ck.getDeclaredField("value"));
6182 >            Class<?> ak = Node[].class;
6183 >            ABASE = U.arrayBaseOffset(ak);
6184 >            int scale = U.arrayIndexScale(ak);
6185 >            if ((scale & (scale - 1)) != 0)
6186 >                throw new Error("data type scale not a power of two");
6187 >            ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6188          } catch (Exception e) {
6189              throw new Error(e);
6190          }
6749        if ((ss & (ss-1)) != 0)
6750            throw new Error("data type scale not a power of two");
6751        ASHIFT = 31 - Integer.numberOfLeadingZeros(ss);
6191      }
6192  
6193      /**
# Line 6761 | Line 6200 | public class ConcurrentHashMapV8<K, V>
6200      private static sun.misc.Unsafe getUnsafe() {
6201          try {
6202              return sun.misc.Unsafe.getUnsafe();
6203 <        } catch (SecurityException se) {
6204 <            try {
6205 <                return java.security.AccessController.doPrivileged
6206 <                    (new java.security
6207 <                     .PrivilegedExceptionAction<sun.misc.Unsafe>() {
6208 <                        public sun.misc.Unsafe run() throws Exception {
6209 <                            java.lang.reflect.Field f = sun.misc
6210 <                                .Unsafe.class.getDeclaredField("theUnsafe");
6211 <                            f.setAccessible(true);
6212 <                            return (sun.misc.Unsafe) f.get(null);
6213 <                        }});
6214 <            } catch (java.security.PrivilegedActionException e) {
6215 <                throw new RuntimeException("Could not initialize intrinsics",
6216 <                                           e.getCause());
6217 <            }
6203 >        } catch (SecurityException tryReflectionInstead) {}
6204 >        try {
6205 >            return java.security.AccessController.doPrivileged
6206 >            (new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
6207 >                public sun.misc.Unsafe run() throws Exception {
6208 >                    Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
6209 >                    for (java.lang.reflect.Field f : k.getDeclaredFields()) {
6210 >                        f.setAccessible(true);
6211 >                        Object x = f.get(null);
6212 >                        if (k.isInstance(x))
6213 >                            return k.cast(x);
6214 >                    }
6215 >                    throw new NoSuchFieldError("the Unsafe");
6216 >                }});
6217 >        } catch (java.security.PrivilegedActionException e) {
6218 >            throw new RuntimeException("Could not initialize intrinsics",
6219 >                                       e.getCause());
6220          }
6221      }
6222   }

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