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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.43 by jsr166, Wed Jul 4 20:21:02 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 >
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;
10 import java.util.Map;
11 import java.util.Set;
17   import java.util.Collection;
18 < import java.util.AbstractMap;
19 < import java.util.AbstractSet;
20 < import java.util.AbstractCollection;
16 < 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;
20 < 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;
28 < import java.util.concurrent.ThreadLocalRandom;
28 > import java.util.concurrent.atomic.AtomicReference;
29 > import java.util.concurrent.atomic.AtomicInteger;
30   import java.util.concurrent.locks.LockSupport;
31 < import java.util.concurrent.locks.AbstractQueuedSynchronizer;
26 < import java.io.Serializable;
31 > import java.util.concurrent.locks.ReentrantLock;
32  
33   /**
34   * A hash table supporting full concurrency of retrievals and
# Line 37 | 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
49 < * onset.  For aggregate operations such as {@code putAll} and {@code
50 < * clear}, concurrent retrievals may reflect insertion or removal of
51 < * only some entries.  Similarly, Iterators and Enumerations return
52 < * elements reflecting the state of the hash table at some point at or
53 < * since the creation of the iterator/enumeration.  They do
54 < * <em>not</em> throw {@link ConcurrentModificationException}.
55 < * However, iterators are designed to be used by only one thread at a
56 < * time.  Bear in mind that the results of aggregate status methods
57 < * including {@code size}, {@code isEmpty}, and {@code containsValue}
58 < * are typically useful only when a map is not undergoing concurrent
59 < * updates in other threads.  Otherwise the results of these methods
60 < * reflect transient states that may be adequate for monitoring
61 < * or estimation purposes, but not for program control.
49 > * onset. (More formally, an update operation for a given key bears a
50 > * <em>happens-before</em> relation with any (non-null) retrieval for
51 > * that key reporting the updated value.)  For aggregate operations
52 > * such as {@code putAll} and {@code clear}, concurrent retrievals may
53 > * reflect insertion or removal of only some entries.  Similarly,
54 > * Iterators and Enumerations return elements reflecting the state of
55 > * the hash table at some point at or since the creation of the
56 > * iterator/enumeration.  They do <em>not</em> throw {@link
57 > * ConcurrentModificationException}.  However, iterators are designed
58 > * to be used by only one thread at a time.  Bear in mind that the
59 > * results of aggregate status methods including {@code size}, {@code
60 > * isEmpty}, and {@code containsValue} are typically useful only when
61 > * a map is not undergoing concurrent updates in other threads.
62 > * Otherwise the results of these methods reflect transient states
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 74 | 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   *
90 * <p><em>jsr166e note: This class is a candidate replacement for
91 * java.util.concurrent.ConcurrentHashMap.<em>
92 *
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 function computing a mapping from the given key to a value.
228 <     * This is a place-holder for an upcoming JDK8 interface.
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 MappingFunction<K, V> {
231 >    public static interface ConcurrentHashMapSpliterator<T> {
232          /**
233 <         * Returns a value for the given key, or null if there is no mapping.
234 <         *
235 <         * @param key the (non-null) key
236 <         * @return a value for the key, or null if none
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 <        V map(K key);
114 <    }
115 <
116 <    /**
117 <     * A function computing a new mapping given a key and its current
118 <     * mapped value (or {@code null} if there is no current
119 <     * mapping). This is a place-holder for an upcoming JDK8
120 <     * interface.
121 <     */
122 <    public static interface RemappingFunction<K, V> {
238 >        ConcurrentHashMapSpliterator<T> trySplit();
239          /**
240 <         * Returns a new value given a key and its current value.
241 <         *
126 <         * @param key the (non-null) key
127 <         * @param value the current value, or null if there is no mapping
128 <         * @return a value for the key, or null if none
129 <         */
130 <        V remap(K key, V value);
131 <    }
132 <
133 <    /**
134 <     * A partitionable iterator. A Spliterator can be traversed
135 <     * directly, but can also be partitioned (before traversal) by
136 <     * creating another Spliterator that covers a non-overlapping
137 <     * portion of the elements, and so may be amenable to parallel
138 <     * execution.
139 <     *
140 <     * <p> This interface exports a subset of expected JDK8
141 <     * functionality.
142 <     *
143 <     * <p>Sample usage: Here is one (of the several) ways to compute
144 <     * the sum of the values held in a map using the ForkJoin
145 <     * framework. As illustrated here, Spliterators are well suited to
146 <     * designs in which a task repeatedly splits off half its work
147 <     * into forked subtasks until small enough to process directly,
148 <     * and then joins these subtasks. Variants of this style can be
149 <     * also be used in completion-based designs.
150 <     *
151 <     * <pre>
152 <     * {@code ConcurrentHashMapV8<String, Long> m = ...
153 <     * // Uses parallel depth of log2 of size / (parallelism * slack of 8).
154 <     * int depth = 32 - Integer.numberOfLeadingZeros(m.size() / (aForkJoinPool.getParallelism() * 8));
155 <     * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), depth, null));
156 <     * // ...
157 <     * static class SumValues extends RecursiveTask<Long> {
158 <     *   final Spliterator<Long> s;
159 <     *   final int depth;             // number of splits before processing
160 <     *   final SumValues nextJoin;    // records forked subtasks to join
161 <     *   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
162 <     *     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
163 <     *   }
164 <     *   public Long compute() {
165 <     *     long sum = 0;
166 <     *     SumValues subtasks = null; // fork subtasks
167 <     *     for (int d = depth - 1; d >= 0; --d)
168 <     *       (subtasks = new SumValues(s.split(), d, subtasks)).fork();
169 <     *     while (s.hasNext())        // directly process remaining elements
170 <     *       sum += s.next();
171 <     *     for (SumValues t = subtasks; t != null; t = t.nextJoin)
172 <     *       sum += t.join();         // collect subtask results
173 <     *     return sum;
174 <     *   }
175 <     * }
176 <     * }</pre>
177 <     */
178 <    public static interface Spliterator<T> extends Iterator<T> {
179 <        /**
180 <         * Returns a Spliterator covering approximately half of the
181 <         * elements, guaranteed not to overlap with those subsequently
182 <         * returned by this Spliterator.  After invoking this method,
183 <         * the current Spliterator will <em>not</em> produce any of
184 <         * the elements of the returned Spliterator, but the two
185 <         * Spliterators together will produce all of the elements that
186 <         * would have been produced by this Spliterator had this
187 <         * method not been called. The exact number of elements
188 <         * produced by the returned Spliterator is not guaranteed, and
189 <         * may be zero (i.e., with {@code hasNext()} reporting {@code
190 <         * false}) if this Spliterator cannot be further split.
191 <         *
192 <         * @return a Spliterator covering approximately half of the
193 <         * elements
194 <         * @throws IllegalStateException if this Spliterator has
195 <         * already commenced traversing elements.
196 <         */
197 <        Spliterator<T> split();
198 <
199 <        /**
200 <         * Returns a Spliterator producing the same elements as this
201 <         * Spliterator. This method may be used for example to create
202 <         * a second Spliterator before a traversal, in order to later
203 <         * perform a second traversal.
204 <         *
205 <         * @return a Spliterator covering the same range as this Spliterator.
206 <         * @throws IllegalStateException if this Spliterator has
207 <         * already commenced traversing elements.
240 >         * Returns an estimate of the number of elements covered by
241 >         * this Spliterator.
242           */
243 <        Spliterator<T> clone();
244 <    }
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:
# Line 219 | 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 238 | 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
247 <     * purposes -- they are available anyway because of addressing
248 <     * constraints.  As explained further below, these top bits are
249 <     * used as follows:
250 <     *  00 - Normal
251 <     *  01 - Locked
252 <     *  11 - Locked and may have a thread waiting for lock
253 <     *  10 - Node is a forwarding node
254 <     *
255 <     * The lower 30 bits of each Node's hash field contain a
256 <     * transformation of the key's hash code, except for forwarding
257 <     * nodes, for which the lower bits are zero (and so always have
258 <     * 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 264 | 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
269 <     * construction, so we overlay these by using bits of the Node
270 <     * hash field for lock control (see above), and so normally use
271 <     * builtin monitors only for blocking and signalling using
272 <     * 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,
280 <     * operations that only conditionally update may inspect nodes
281 <     * until the point of update. This is a converse of sorts to the
282 <     * 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 312 | 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
321 <     * Comparable.  These TreeBins use a balanced tree to hold nodes
322 <     * (a specialized form of red-black trees), bounding search time
323 <     * 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 331 | 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 InternalIterator) 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 InternalIterator constructor)
421 >     * ranges of bins (via an alternate Traverser constructor)
422       * to support partitioned aggregate operations.  Also, read-only
423       * operations give up if ever forwarded to a null table, which
424       * provides support for shutdown-style clearing, which is also not
# Line 382 | 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 405 | 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 446 | Line 539 | public class ConcurrentHashMapV8<K, V>
539      private static final float LOAD_FACTOR = 0.75f;
540  
541      /**
449     * The buffer size for skipped bins during transfers. The
450     * value is arbitrary but should be large enough to avoid
451     * most locking stalls during resizes.
452     */
453    private static final int TRANSFER_BUFFER_SIZE = 32;
454
455    /**
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.
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 <    private static final int TREE_THRESHOLD = 8;
461 <
462 <    /*
463 <     * Encodings for special uses of Node hash fields. See above for
464 <     * explanation.
465 <     */
466 <    static final int MOVED     = 0x80000000; // hash field for forwarding nodes
467 <    static final int LOCKED    = 0x40000000; // set/tested only as a bit
468 <    static final int WAITING   = 0xc0000000; // both bits set/tested together
469 <    static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
470 <
471 <    /* ---------------- 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;
492 <
493 <    // views
494 <    private transient KeySet<K,V> keySet;
495 <    private transient Values<K,V> values;
496 <    private transient EntrySet<K,V> entrySet;
497 <
498 <    /** For serialization compatibility. Null unless serialized; see below */
499 <    private Segment<K,V>[] segments;
500 <
501 <    /* ---------------- 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
505 <     * elements of in-progress next table while resizing.  Uses are
506 <     * null checked by callers, and implicitly bounds-checked, relying
507 <     * on the invariants that tab arrays have non-zero size, and all
508 <     * indices are masked with (tab.length - 1) which is never
509 <     * negative and always less than length. Note that, to be correct
510 <     * wrt arbitrary concurrency errors by users, bounds checks must
511 <     * operate on local variables, which accounts for some odd-looking
512 <     * 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 InternalIterator
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;
542 <        volatile Object val;
543 <        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 */
558 <        static final int MAX_SPINS =
559 <            Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
560 <
561 <        /**
562 <         * Spins a while if LOCKED bit set and this node is the first
563 <         * of its bin, and then sets WAITING bits on hash field and
564 <         * blocks (once) if they are still set.  It is OK for this
565 <         * method to return even if lock is not available upon exit,
566 <         * which enables these simple single-wait mechanics.
567 <         *
568 <         * The corresponding signalling operation is performed within
569 <         * callers: Upon detecting that WAITING has been set when
570 <         * unlocking lock (via a failed CAS from non-waiting LOCKED
571 <         * state), unlockers acquire the sync lock and perform a
572 <         * notifyAll.
573 <         */
574 <        final void tryAwaitLock(Node[] tab, int i) {
575 <            if (tab != null && i >= 0 && i < tab.length) { // bounds check
576 <                int r = ThreadLocalRandom.current().nextInt(); // randomize spins
577 <                int spins = MAX_SPINS, h;
578 <                while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
579 <                    if (spins >= 0) {
580 <                        r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
581 <                        if (r >= 0 && --spins == 0)
582 <                            Thread.yield();  // yield before block
583 <                    }
584 <                    else if (casHash(h, h | WAITING)) {
585 <                        synchronized (this) {
586 <                            if (tabAt(tab, i) == this &&
587 <                                (hash & WAITING) == WAITING) {
588 <                                try {
589 <                                    wait();
590 <                                } catch (InterruptedException ie) {
591 <                                    Thread.currentThread().interrupt();
592 <                                }
593 <                            }
594 <                            else
595 <                                notifyAll(); // possibly won race vs signaller
596 <                        }
597 <                        break;
598 <                    }
599 <                }
600 <            }
601 <        }
602 <
603 <        // Unsafe mechanics for casHash
604 <        private static final sun.misc.Unsafe UNSAFE;
605 <        private static final long hashOffset;
606 <
607 <        static {
608 <            try {
609 <                UNSAFE = getUnsafe();
610 <                Class<?> k = Node.class;
611 <                hashOffset = UNSAFE.objectFieldOffset
612 <                    (k.getDeclaredField("hash"));
613 <            } catch (Exception e) {
614 <                throw new Error(e);
615 <            }
616 <        }
617 <    }
618 <
619 <    /* ---------------- TreeBins -------------- */
620 <
621 <    /**
622 <     * Nodes for use in TreeBins
623 <     */
624 <    static final class TreeNode extends Node {
625 <        TreeNode parent;  // red-black tree links
626 <        TreeNode left;
627 <        TreeNode right;
628 <        TreeNode prev;    // needed to unlink next upon deletion
629 <        boolean red;
630 <
631 <        TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
632 <            super(hash, key, val, next);
633 <            this.parent = parent;
634 <        }
635 <    }
636 <
637 <    /**
638 <     * A specialized form of red-black tree for use in bins
639 <     * whose size exceeds a threshold.
640 <     *
641 <     * TreeBins use a special form of comparison for search and
642 <     * related operations (which is the main reason we cannot use
643 <     * existing collections such as TreeMaps). TreeBins contain
644 <     * Comparable elements, but may contain others, as well as
645 <     * elements that are Comparable but not necessarily Comparable<T>
646 <     * for the same T, so we cannot invoke compareTo among them. To
647 <     * handle this, the tree is ordered primarily by hash value, then
648 <     * by getClass().getName() order, and then by Comparator order
649 <     * among elements of the same class.  On lookup at a node, if
650 <     * elements are not comparable or compare as 0, both left and
651 <     * right children may need to be searched in the case of tied hash
652 <     * values. (This corresponds to the full list search that would be
653 <     * necessary if all elements were non-Comparable and had tied
654 <     * hashes.)  The red-black balancing code is updated from
655 <     * pre-jdk-collections
656 <     * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
657 <     * based in turn on Cormen, Leiserson, and Rivest "Introduction to
658 <     * Algorithms" (CLR).
659 <     *
660 <     * TreeBins also maintain a separate locking discipline than
661 <     * regular bins. Because they are forwarded via special MOVED
662 <     * nodes at bin heads (which can never change once established),
663 <     * we cannot use use those nodes as locks. Instead, TreeBin
664 <     * extends AbstractQueuedSynchronizer to support a simple form of
665 <     * read-write lock. For update operations and table validation,
666 <     * the exclusive form of lock behaves in the same way as bin-head
667 <     * locks. However, lookups use shared read-lock mechanics to allow
668 <     * multiple readers in the absence of writers.  Additionally,
669 <     * these lookups do not ever block: While the lock is not
670 <     * available, they proceed along the slow traversal path (via
671 <     * next-pointers) until the lock becomes available or the list is
672 <     * exhausted, whichever comes first. (These cases are not fast,
673 <     * but maximize aggregate expected throughput.)  The AQS mechanics
674 <     * for doing this are straightforward.  The lock state is held as
675 <     * AQS getState().  Read counts are negative; the write count (1)
676 <     * is positive.  There are no signalling preferences among readers
677 <     * and writers. Since we don't need to export full Lock API, we
678 <     * just override the minimal AQS methods and use them directly.
679 <     */
680 <    static final class TreeBin extends AbstractQueuedSynchronizer {
681 <        private static final long serialVersionUID = 2249069246763182397L;
682 <        transient TreeNode root;  // root of tree
683 <        transient TreeNode first; // head of next-pointer list
684 <
685 <        /* AQS overrides */
686 <        public final boolean isHeldExclusively() { return getState() > 0; }
687 <        public final boolean tryAcquire(int ignore) {
688 <            if (compareAndSetState(0, 1)) {
689 <                setExclusiveOwnerThread(Thread.currentThread());
690 <                return true;
691 <            }
692 <            return false;
693 <        }
694 <        public final boolean tryRelease(int ignore) {
695 <            setExclusiveOwnerThread(null);
696 <            setState(0);
697 <            return true;
698 <        }
699 <        public final int tryAcquireShared(int ignore) {
700 <            for (int c;;) {
701 <                if ((c = getState()) > 0)
702 <                    return -1;
703 <                if (compareAndSetState(c, c -1))
704 <                    return 1;
705 <            }
706 <        }
707 <        public final boolean tryReleaseShared(int ignore) {
708 <            int c;
709 <            do {} while (!compareAndSetState(c = getState(), c + 1));
710 <            return c == -1;
711 <        }
712 <
713 <        /** From CLR */
714 <        private void rotateLeft(TreeNode p) {
715 <            if (p != null) {
716 <                TreeNode r = p.right, pp, rl;
717 <                if ((rl = p.right = r.left) != null)
718 <                    rl.parent = p;
719 <                if ((pp = r.parent = p.parent) == null)
720 <                    root = r;
721 <                else if (pp.left == p)
722 <                    pp.left = r;
723 <                else
724 <                    pp.right = r;
725 <                r.left = p;
726 <                p.parent = r;
727 <            }
728 <        }
729 <
730 <        /** From CLR */
731 <        private void rotateRight(TreeNode p) {
732 <            if (p != null) {
733 <                TreeNode l = p.left, pp, lr;
734 <                if ((lr = p.left = l.right) != null)
735 <                    lr.parent = p;
736 <                if ((pp = l.parent = p.parent) == null)
737 <                    root = l;
738 <                else if (pp.right == p)
739 <                    pp.right = l;
740 <                else
741 <                    pp.left = l;
742 <                l.right = p;
743 <                p.parent = l;
744 <            }
745 <        }
746 <
747 <        /**
748 <         * Return the TreeNode (or null if not found) for the given key
749 <         * starting at given root.
750 <         */
751 <        @SuppressWarnings("unchecked") // suppress Comparable cast warning
752 <        final TreeNode getTreeNode(int h, Object k, TreeNode p) {
753 <            Class<?> c = k.getClass();
754 <            while (p != null) {
755 <                int dir, ph;  Object pk; Class<?> pc;
756 <                if ((ph = p.hash) == h) {
757 <                    if ((pk = p.key) == k || k.equals(pk))
758 <                        return p;
759 <                    if (c != (pc = pk.getClass()) ||
760 <                        !(k instanceof Comparable) ||
761 <                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
762 <                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
763 <                        TreeNode r = null, s = null, pl, pr;
764 <                        if (dir >= 0) {
765 <                            if ((pl = p.left) != null && h <= pl.hash)
766 <                                s = pl;
767 <                        }
768 <                        else if ((pr = p.right) != null && h >= pr.hash)
769 <                            s = pr;
770 <                        if (s != null && (r = getTreeNode(h, k, s)) != null)
771 <                            return r;
772 <                    }
773 <                }
774 <                else
775 <                    dir = (h < ph) ? -1 : 1;
776 <                p = (dir > 0) ? p.right : p.left;
777 <            }
778 <            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;
788 <            int c = getState(); // Must read lock state first
789 <            for (Node e = first; e != null; e = e.next) {
790 <                if (c <= 0 && compareAndSetState(c, c - 1)) {
791 <                    try {
792 <                        r = getTreeNode(h, k, root);
793 <                    } finally {
794 <                        releaseShared(0);
795 <                    }
796 <                    break;
797 <                }
798 <                else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
799 <                    r = e;
800 <                    break;
801 <                }
802 <                else
803 <                    c = getState();
804 <            }
805 <            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 <         * Find or add a node
810 <         * @return null if added
634 >         * Virtualized support for map.get(); overridden in subclasses.
635           */
636 <        @SuppressWarnings("unchecked") // suppress Comparable cast warning
637 <        final TreeNode putTreeNode(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) {
821 <                    if ((pk = p.key) == k || k.equals(pk))
822 <                        return p;
823 <                    if (c != (pc = pk.getClass()) ||
824 <                        !(k instanceof Comparable) ||
825 <                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
826 <                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
827 <                        TreeNode r = null, s = null, pl, pr;
828 <                        if (dir >= 0) {
829 <                            if ((pl = p.left) != null && h <= pl.hash)
830 <                                s = pl;
831 <                        }
832 <                        else if ((pr = p.right) != null && h >= pr.hash)
833 <                            s = pr;
834 <                        if (s != null && (r = getTreeNode(h, k, s)) != null)
835 <                            return r;
836 <                    }
837 <                }
838 <                else
839 <                    dir = (h < ph) ? -1 : 1;
840 <                pp = (dir > 0) ? p.right : p.left;
841 <            }
842 <
843 <            TreeNode f = first;
844 <            TreeNode x = first = new TreeNode(h, k, v, f, p);
845 <            if (p == null)
846 <                root = x;
847 <            else { // attach and rebalance; adapted from CLR
848 <                TreeNode xp, xpp;
849 <                if (f != null)
850 <                    f.prev = x;
851 <                if (dir <= 0)
852 <                    p.left = x;
853 <                else
854 <                    p.right = x;
855 <                x.red = true;
856 <                while (x != null && (xp = x.parent) != null && xp.red &&
857 <                       (xpp = xp.parent) != null) {
858 <                    TreeNode xppl = xpp.left;
859 <                    if (xp == xppl) {
860 <                        TreeNode y = xpp.right;
861 <                        if (y != null && y.red) {
862 <                            y.red = false;
863 <                            xp.red = false;
864 <                            xpp.red = true;
865 <                            x = xpp;
866 <                        }
867 <                        else {
868 <                            if (x == xp.right) {
869 <                                rotateLeft(x = xp);
870 <                                xpp = (xp = x.parent) == null ? null : xp.parent;
871 <                            }
872 <                            if (xp != null) {
873 <                                xp.red = false;
874 <                                if (xpp != null) {
875 <                                    xpp.red = true;
876 <                                    rotateRight(xpp);
877 <                                }
878 <                            }
879 <                        }
880 <                    }
881 <                    else {
882 <                        TreeNode y = xppl;
883 <                        if (y != null && y.red) {
884 <                            y.red = false;
885 <                            xp.red = false;
886 <                            xpp.red = true;
887 <                            x = xpp;
888 <                        }
889 <                        else {
890 <                            if (x == xp.left) {
891 <                                rotateRight(x = xp);
892 <                                xpp = (xp = x.parent) == null ? null : xp.parent;
893 <                            }
894 <                            if (xp != null) {
895 <                                xp.red = false;
896 <                                if (xpp != null) {
897 <                                    xpp.red = true;
898 <                                    rotateLeft(xpp);
899 <                                }
900 <                            }
901 <                        }
902 <                    }
903 <                }
904 <                TreeNode r = root;
905 <                if (r != null && r.red)
906 <                    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          }
910
911        /**
912         * Removes the given node, that must be present before this
913         * call.  This is messier than typical red-black deletion code
914         * because we cannot swap the contents of an interior node
915         * with a leaf successor that is pinned by "next" pointers
916         * that are accessible independently of lock. So instead we
917         * swap the tree linkages.
918         */
919        final void deleteTreeNode(TreeNode p) {
920            TreeNode next = (TreeNode)p.next; // unlink traversal pointers
921            TreeNode pred = p.prev;
922            if (pred == null)
923                first = next;
924            else
925                pred.next = next;
926            if (next != null)
927                next.prev = pred;
928            TreeNode replacement;
929            TreeNode pl = p.left;
930            TreeNode pr = p.right;
931            if (pl != null && pr != null) {
932                TreeNode s = pr, sl;
933                while ((sl = s.left) != null) // find successor
934                    s = sl;
935                boolean c = s.red; s.red = p.red; p.red = c; // swap colors
936                TreeNode sr = s.right;
937                TreeNode pp = p.parent;
938                if (s == pr) { // p was s's direct parent
939                    p.parent = s;
940                    s.right = p;
941                }
942                else {
943                    TreeNode sp = s.parent;
944                    if ((p.parent = sp) != null) {
945                        if (s == sp.left)
946                            sp.left = p;
947                        else
948                            sp.right = p;
949                    }
950                    if ((s.right = pr) != null)
951                        pr.parent = s;
952                }
953                p.left = null;
954                if ((p.right = sr) != null)
955                    sr.parent = p;
956                if ((s.left = pl) != null)
957                    pl.parent = s;
958                if ((s.parent = pp) == null)
959                    root = s;
960                else if (p == pp.left)
961                    pp.left = s;
962                else
963                    pp.right = s;
964                replacement = sr;
965            }
966            else
967                replacement = (pl != null) ? pl : pr;
968            TreeNode pp = p.parent;
969            if (replacement == null) {
970                if (pp == null) {
971                    root = null;
972                    return;
973                }
974                replacement = p;
975            }
976            else {
977                replacement.parent = pp;
978                if (pp == null)
979                    root = replacement;
980                else if (p == pp.left)
981                    pp.left = replacement;
982                else
983                    pp.right = replacement;
984                p.left = p.right = p.parent = null;
985            }
986            if (!p.red) { // rebalance, from CLR
987                TreeNode x = replacement;
988                while (x != null) {
989                    TreeNode xp, xpl;
990                    if (x.red || (xp = x.parent) == null) {
991                        x.red = false;
992                        break;
993                    }
994                    if (x == (xpl = xp.left)) {
995                        TreeNode sib = xp.right;
996                        if (sib != null && sib.red) {
997                            sib.red = false;
998                            xp.red = true;
999                            rotateLeft(xp);
1000                            sib = (xp = x.parent) == null ? null : xp.right;
1001                        }
1002                        if (sib == null)
1003                            x = xp;
1004                        else {
1005                            TreeNode sl = sib.left, sr = sib.right;
1006                            if ((sr == null || !sr.red) &&
1007                                (sl == null || !sl.red)) {
1008                                sib.red = true;
1009                                x = xp;
1010                            }
1011                            else {
1012                                if (sr == null || !sr.red) {
1013                                    if (sl != null)
1014                                        sl.red = false;
1015                                    sib.red = true;
1016                                    rotateRight(sib);
1017                                    sib = (xp = x.parent) == null ? null : xp.right;
1018                                }
1019                                if (sib != null) {
1020                                    sib.red = (xp == null) ? false : xp.red;
1021                                    if ((sr = sib.right) != null)
1022                                        sr.red = false;
1023                                }
1024                                if (xp != null) {
1025                                    xp.red = false;
1026                                    rotateLeft(xp);
1027                                }
1028                                x = root;
1029                            }
1030                        }
1031                    }
1032                    else { // symmetric
1033                        TreeNode sib = xpl;
1034                        if (sib != null && sib.red) {
1035                            sib.red = false;
1036                            xp.red = true;
1037                            rotateRight(xp);
1038                            sib = (xp = x.parent) == null ? null : xp.left;
1039                        }
1040                        if (sib == null)
1041                            x = xp;
1042                        else {
1043                            TreeNode sl = sib.left, sr = sib.right;
1044                            if ((sl == null || !sl.red) &&
1045                                (sr == null || !sr.red)) {
1046                                sib.red = true;
1047                                x = xp;
1048                            }
1049                            else {
1050                                if (sl == null || !sl.red) {
1051                                    if (sr != null)
1052                                        sr.red = false;
1053                                    sib.red = true;
1054                                    rotateLeft(sib);
1055                                    sib = (xp = x.parent) == null ? null : xp.left;
1056                                }
1057                                if (sib != null) {
1058                                    sib.red = (xp == null) ? false : xp.red;
1059                                    if ((sl = sib.left) != null)
1060                                        sl.red = false;
1061                                }
1062                                if (xp != null) {
1063                                    xp.red = false;
1064                                    rotateRight(xp);
1065                                }
1066                                x = root;
1067                            }
1068                        }
1069                    }
1070                }
1071            }
1072            if (p == replacement && (pp = p.parent) != null) {
1073                if (p == pp.left) // detach pointers
1074                    pp.left = null;
1075                else if (p == pp.right)
1076                    pp.right = null;
1077                p.parent = null;
1078            }
1079        }
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.
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 static final int spread(int h) {
669 <        h ^= (h >>> 18) ^ (h >>> 12);
1099 <        return (h ^ (h >>> 10)) & HASH_BITS;
668 >    static final int spread(int h) {
669 >        return (h ^ (h >>> 16)) & HASH_BITS;
670      }
671  
672      /**
673 <     * Replaces a list bin with a tree bin. Call only when locked.
674 <     * Fails to replace if the given key is non-comparable or table
1105 <     * is, or needs, resizing.
673 >     * Returns a power of two table size for the given desired capacity.
674 >     * See Hackers Delight, sec 3.2
675       */
676 <    private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
677 <        if ((key instanceof Comparable) &&
678 <            (tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
679 <            TreeBin t = new TreeBin();
680 <            for (Node e = tabAt(tab, index); e != null; e = e.next)
681 <                t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
682 <            setTabAt(tab, index, new Node(MOVED, t, null, null));
683 <        }
676 >    private static final int tableSizeFor(int c) {
677 >        int n = c - 1;
678 >        n |= n >>> 1;
679 >        n |= n >>> 2;
680 >        n |= n >>> 4;
681 >        n |= n >>> 8;
682 >        n |= n >>> 16;
683 >        return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
684      }
685  
686 <    /* ---------------- Internal access and update methods -------------- */
687 <
688 <    /** Implementation for get and containsKey */
689 <    private final Object internalGet(Object k) {
690 <        int h = spread(k.hashCode());
691 <        retry: for (Node[] tab = table; tab != null;) {
692 <            Node e, p; Object ek, ev; int eh;      // locals to read fields once
693 <            for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
694 <                if ((eh = e.hash) == MOVED) {
695 <                    if ((ek = e.key) instanceof TreeBin)  // search TreeBin
696 <                        return ((TreeBin)ek).getValue(h, k);
697 <                    else {                        // restart with new table
698 <                        tab = (Node[])ek;
699 <                        continue retry;
700 <                    }
686 >    /**
687 >     * Returns x's Class if it is of the form "class C implements
688 >     * Comparable<C>", else null.
689 >     */
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                  }
1133                else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1134                         ((ek = e.key) == k || k.equals(ek)))
1135                    return ev;
704              }
1137            break;
705          }
706          return null;
707      }
708  
709      /**
710 <     * Implementation for the four public remove/replace methods:
711 <     * Replaces node value with v, conditional upon match of cv if
1145 <     * non-null.  If resulting value is null, delete.
710 >     * Returns k.compareTo(x) if x matches kc (k's screened comparable
711 >     * class), else 0.
712       */
713 <    private final Object internalReplace(Object k, Object v, Object cv) {
714 <        int h = spread(k.hashCode());
715 <        Object oldVal = null;
716 <        for (Node[] tab = table;;) {
1151 <            Node f; int i, fh; Object fk;
1152 <            if (tab == null ||
1153 <                (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1154 <                break;
1155 <            else if ((fh = f.hash) == MOVED) {
1156 <                if ((fk = f.key) instanceof TreeBin) {
1157 <                    TreeBin t = (TreeBin)fk;
1158 <                    boolean validated = false;
1159 <                    boolean deleted = false;
1160 <                    t.acquire(0);
1161 <                    try {
1162 <                        if (tabAt(tab, i) == f) {
1163 <                            validated = true;
1164 <                            TreeNode p = t.getTreeNode(h, k, t.root);
1165 <                            if (p != null) {
1166 <                                Object pv = p.val;
1167 <                                if (cv == null || cv == pv || cv.equals(pv)) {
1168 <                                    oldVal = pv;
1169 <                                    if ((p.val = v) == null) {
1170 <                                        deleted = true;
1171 <                                        t.deleteTreeNode(p);
1172 <                                    }
1173 <                                }
1174 <                            }
1175 <                        }
1176 <                    } finally {
1177 <                        t.release(0);
1178 <                    }
1179 <                    if (validated) {
1180 <                        if (deleted)
1181 <                            counter.add(-1L);
1182 <                        break;
1183 <                    }
1184 <                }
1185 <                else
1186 <                    tab = (Node[])fk;
1187 <            }
1188 <            else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1189 <                break;                          // rules out possible existence
1190 <            else if ((fh & LOCKED) != 0) {
1191 <                checkForResize();               // try resizing if can't get lock
1192 <                f.tryAwaitLock(tab, i);
1193 <            }
1194 <            else if (f.casHash(fh, fh | LOCKED)) {
1195 <                boolean validated = false;
1196 <                boolean deleted = false;
1197 <                try {
1198 <                    if (tabAt(tab, i) == f) {
1199 <                        validated = true;
1200 <                        for (Node e = f, pred = null;;) {
1201 <                            Object ek, ev;
1202 <                            if ((e.hash & HASH_BITS) == h &&
1203 <                                ((ev = e.val) != null) &&
1204 <                                ((ek = e.key) == k || k.equals(ek))) {
1205 <                                if (cv == null || cv == ev || cv.equals(ev)) {
1206 <                                    oldVal = ev;
1207 <                                    if ((e.val = v) == null) {
1208 <                                        deleted = true;
1209 <                                        Node en = e.next;
1210 <                                        if (pred != null)
1211 <                                            pred.next = en;
1212 <                                        else
1213 <                                            setTabAt(tab, i, en);
1214 <                                    }
1215 <                                }
1216 <                                break;
1217 <                            }
1218 <                            pred = e;
1219 <                            if ((e = e.next) == null)
1220 <                                break;
1221 <                        }
1222 <                    }
1223 <                } finally {
1224 <                    if (!f.casHash(fh | LOCKED, fh)) {
1225 <                        f.hash = fh;
1226 <                        synchronized (f) { f.notifyAll(); };
1227 <                    }
1228 <                }
1229 <                if (validated) {
1230 <                    if (deleted)
1231 <                        counter.add(-1L);
1232 <                    break;
1233 <                }
1234 <            }
1235 <        }
1236 <        return oldVal;
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 <    /*
1240 <     * Internal versions of the five insertion methods, each a
1241 <     * little more complicated than the last. All have
1242 <     * the same basic structure as the first (internalPut):
1243 <     *  1. If table uninitialized, create
1244 <     *  2. If bin empty, try to CAS new node
1245 <     *  3. If bin stale, use new table
1246 <     *  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1247 <     *  5. Lock and validate; if valid, scan and add or update
1248 <     *
1249 <     * The others interweave other checks and/or alternative actions:
1250 <     *  * Plain put checks for and performs resize after insertion.
1251 <     *  * putIfAbsent prescans for mapping without lock (and fails to add
1252 <     *    if present), which also makes pre-emptive resize checks worthwhile.
1253 <     *  * computeIfAbsent extends form used in putIfAbsent with additional
1254 <     *    mechanics to deal with, calls, potential exceptions and null
1255 <     *    returns from function call.
1256 <     *  * compute uses the same function-call mechanics, but without
1257 <     *    the prescans
1258 <     *  * putAll attempts to pre-allocate enough table space
1259 <     *    and more lazily performs count updates and checks.
1260 <     *
1261 <     * Someday when details settle down a bit more, it might be worth
1262 <     * some factoring to reduce sprawl.
1263 <     */
1264 <
1265 <    /** Implementation for put */
1266 <    private final Object internalPut(Object k, Object v) {
1267 <        int h = spread(k.hashCode());
1268 <        int count = 0;
1269 <        for (Node[] tab = table;;) {
1270 <            int i; Node f; int fh; Object fk;
1271 <            if (tab == null)
1272 <                tab = initTable();
1273 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1274 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1275 <                    break;                   // no lock when adding to empty bin
1276 <            }
1277 <            else if ((fh = f.hash) == MOVED) {
1278 <                if ((fk = f.key) instanceof TreeBin) {
1279 <                    TreeBin t = (TreeBin)fk;
1280 <                    Object oldVal = null;
1281 <                    t.acquire(0);
1282 <                    try {
1283 <                        if (tabAt(tab, i) == f) {
1284 <                            count = 2;
1285 <                            TreeNode p = t.putTreeNode(h, k, v);
1286 <                            if (p != null) {
1287 <                                oldVal = p.val;
1288 <                                p.val = v;
1289 <                            }
1290 <                        }
1291 <                    } finally {
1292 <                        t.release(0);
1293 <                    }
1294 <                    if (count != 0) {
1295 <                        if (oldVal != null)
1296 <                            return oldVal;
1297 <                        break;
1298 <                    }
1299 <                }
1300 <                else
1301 <                    tab = (Node[])fk;
1302 <            }
1303 <            else if ((fh & LOCKED) != 0) {
1304 <                checkForResize();
1305 <                f.tryAwaitLock(tab, i);
1306 <            }
1307 <            else if (f.casHash(fh, fh | LOCKED)) {
1308 <                Object oldVal = null;
1309 <                try {                        // needed in case equals() throws
1310 <                    if (tabAt(tab, i) == f) {
1311 <                        count = 1;
1312 <                        for (Node e = f;; ++count) {
1313 <                            Object ek, ev;
1314 <                            if ((e.hash & HASH_BITS) == h &&
1315 <                                (ev = e.val) != null &&
1316 <                                ((ek = e.key) == k || k.equals(ek))) {
1317 <                                oldVal = ev;
1318 <                                e.val = v;
1319 <                                break;
1320 <                            }
1321 <                            Node last = e;
1322 <                            if ((e = e.next) == null) {
1323 <                                last.next = new Node(h, k, v, null);
1324 <                                if (count >= TREE_THRESHOLD)
1325 <                                    replaceWithTreeBin(tab, i, k);
1326 <                                break;
1327 <                            }
1328 <                        }
1329 <                    }
1330 <                } finally {                  // unlock and signal if needed
1331 <                    if (!f.casHash(fh | LOCKED, fh)) {
1332 <                        f.hash = fh;
1333 <                        synchronized (f) { f.notifyAll(); };
1334 <                    }
1335 <                }
1336 <                if (count != 0) {
1337 <                    if (oldVal != null)
1338 <                        return oldVal;
1339 <                    if (tab.length <= 64)
1340 <                        count = 2;
1341 <                    break;
1342 <                }
1343 <            }
1344 <        }
1345 <        counter.add(1L);
1346 <        if (count > 1)
1347 <            checkForResize();
1348 <        return null;
1349 <    }
719 >    /* ---------------- Table element access -------------- */
720  
721 <    /** Implementation for putIfAbsent */
722 <    private final Object internalPutIfAbsent(Object k, Object v) {
723 <        int h = spread(k.hashCode());
724 <        int count = 0;
725 <        for (Node[] tab = table;;) {
726 <            int i; Node f; int fh; Object fk, fv;
727 <            if (tab == null)
728 <                tab = initTable();
729 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
730 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
731 <                    break;
732 <            }
733 <            else if ((fh = f.hash) == MOVED) {
734 <                if ((fk = f.key) instanceof TreeBin) {
735 <                    TreeBin t = (TreeBin)fk;
1366 <                    Object oldVal = null;
1367 <                    t.acquire(0);
1368 <                    try {
1369 <                        if (tabAt(tab, i) == f) {
1370 <                            count = 2;
1371 <                            TreeNode p = t.putTreeNode(h, k, v);
1372 <                            if (p != null)
1373 <                                oldVal = p.val;
1374 <                        }
1375 <                    } finally {
1376 <                        t.release(0);
1377 <                    }
1378 <                    if (count != 0) {
1379 <                        if (oldVal != null)
1380 <                            return oldVal;
1381 <                        break;
1382 <                    }
1383 <                }
1384 <                else
1385 <                    tab = (Node[])fk;
1386 <            }
1387 <            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1388 <                     ((fk = f.key) == k || k.equals(fk)))
1389 <                return fv;
1390 <            else {
1391 <                Node g = f.next;
1392 <                if (g != null) { // at least 2 nodes -- search and maybe resize
1393 <                    for (Node e = g;;) {
1394 <                        Object ek, ev;
1395 <                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1396 <                            ((ek = e.key) == k || k.equals(ek)))
1397 <                            return ev;
1398 <                        if ((e = e.next) == null) {
1399 <                            checkForResize();
1400 <                            break;
1401 <                        }
1402 <                    }
1403 <                }
1404 <                if (((fh = f.hash) & LOCKED) != 0) {
1405 <                    checkForResize();
1406 <                    f.tryAwaitLock(tab, i);
1407 <                }
1408 <                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1409 <                    Object oldVal = null;
1410 <                    try {
1411 <                        if (tabAt(tab, i) == f) {
1412 <                            count = 1;
1413 <                            for (Node e = f;; ++count) {
1414 <                                Object ek, ev;
1415 <                                if ((e.hash & HASH_BITS) == h &&
1416 <                                    (ev = e.val) != null &&
1417 <                                    ((ek = e.key) == k || k.equals(ek))) {
1418 <                                    oldVal = ev;
1419 <                                    break;
1420 <                                }
1421 <                                Node last = e;
1422 <                                if ((e = e.next) == null) {
1423 <                                    last.next = new Node(h, k, v, null);
1424 <                                    if (count >= TREE_THRESHOLD)
1425 <                                        replaceWithTreeBin(tab, i, k);
1426 <                                    break;
1427 <                                }
1428 <                            }
1429 <                        }
1430 <                    } finally {
1431 <                        if (!f.casHash(fh | LOCKED, fh)) {
1432 <                            f.hash = fh;
1433 <                            synchronized (f) { f.notifyAll(); };
1434 <                        }
1435 <                    }
1436 <                    if (count != 0) {
1437 <                        if (oldVal != null)
1438 <                            return oldVal;
1439 <                        if (tab.length <= 64)
1440 <                            count = 2;
1441 <                        break;
1442 <                    }
1443 <                }
1444 <            }
1445 <        }
1446 <        counter.add(1L);
1447 <        if (count > 1)
1448 <            checkForResize();
1449 <        return null;
1450 <    }
721 >    /*
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 <    /** Implementation for computeIfAbsent */
738 <    private final Object internalComputeIfAbsent(K k,
739 <                                                 MappingFunction<? super K, ?> mf) {
1455 <        int h = spread(k.hashCode());
1456 <        Object val = null;
1457 <        int count = 0;
1458 <        for (Node[] tab = table;;) {
1459 <            Node f; int i, fh; Object fk, fv;
1460 <            if (tab == null)
1461 <                tab = initTable();
1462 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1463 <                Node node = new Node(fh = h | LOCKED, k, null, null);
1464 <                if (casTabAt(tab, i, null, node)) {
1465 <                    count = 1;
1466 <                    try {
1467 <                        if ((val = mf.map(k)) != null)
1468 <                            node.val = val;
1469 <                    } finally {
1470 <                        if (val == null)
1471 <                            setTabAt(tab, i, null);
1472 <                        if (!node.casHash(fh, h)) {
1473 <                            node.hash = h;
1474 <                            synchronized (node) { node.notifyAll(); };
1475 <                        }
1476 <                    }
1477 <                }
1478 <                if (count != 0)
1479 <                    break;
1480 <            }
1481 <            else if ((fh = f.hash) == MOVED) {
1482 <                if ((fk = f.key) instanceof TreeBin) {
1483 <                    TreeBin t = (TreeBin)fk;
1484 <                    boolean added = false;
1485 <                    t.acquire(0);
1486 <                    try {
1487 <                        if (tabAt(tab, i) == f) {
1488 <                            count = 1;
1489 <                            TreeNode p = t.getTreeNode(h, k, t.root);
1490 <                            if (p != null)
1491 <                                val = p.val;
1492 <                            else if ((val = mf.map(k)) != null) {
1493 <                                added = true;
1494 <                                count = 2;
1495 <                                t.putTreeNode(h, k, val);
1496 <                            }
1497 <                        }
1498 <                    } finally {
1499 <                        t.release(0);
1500 <                    }
1501 <                    if (count != 0) {
1502 <                        if (!added)
1503 <                            return val;
1504 <                        break;
1505 <                    }
1506 <                }
1507 <                else
1508 <                    tab = (Node[])fk;
1509 <            }
1510 <            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1511 <                     ((fk = f.key) == k || k.equals(fk)))
1512 <                return fv;
1513 <            else {
1514 <                Node g = f.next;
1515 <                if (g != null) {
1516 <                    for (Node e = g;;) {
1517 <                        Object ek, ev;
1518 <                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1519 <                            ((ek = e.key) == k || k.equals(ek)))
1520 <                            return ev;
1521 <                        if ((e = e.next) == null) {
1522 <                            checkForResize();
1523 <                            break;
1524 <                        }
1525 <                    }
1526 <                }
1527 <                if (((fh = f.hash) & LOCKED) != 0) {
1528 <                    checkForResize();
1529 <                    f.tryAwaitLock(tab, i);
1530 <                }
1531 <                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1532 <                    boolean added = false;
1533 <                    try {
1534 <                        if (tabAt(tab, i) == f) {
1535 <                            count = 1;
1536 <                            for (Node e = f;; ++count) {
1537 <                                Object ek, ev;
1538 <                                if ((e.hash & HASH_BITS) == h &&
1539 <                                    (ev = e.val) != null &&
1540 <                                    ((ek = e.key) == k || k.equals(ek))) {
1541 <                                    val = ev;
1542 <                                    break;
1543 <                                }
1544 <                                Node last = e;
1545 <                                if ((e = e.next) == null) {
1546 <                                    if ((val = mf.map(k)) != null) {
1547 <                                        added = true;
1548 <                                        last.next = new Node(h, k, val, null);
1549 <                                        if (count >= TREE_THRESHOLD)
1550 <                                            replaceWithTreeBin(tab, i, k);
1551 <                                    }
1552 <                                    break;
1553 <                                }
1554 <                            }
1555 <                        }
1556 <                    } finally {
1557 <                        if (!f.casHash(fh | LOCKED, fh)) {
1558 <                            f.hash = fh;
1559 <                            synchronized (f) { f.notifyAll(); };
1560 <                        }
1561 <                    }
1562 <                    if (count != 0) {
1563 <                        if (!added)
1564 <                            return val;
1565 <                        if (tab.length <= 64)
1566 <                            count = 2;
1567 <                        break;
1568 <                    }
1569 <                }
1570 <            }
1571 <        }
1572 <        if (val != null) {
1573 <            counter.add(1L);
1574 <            if (count > 1)
1575 <                checkForResize();
1576 <        }
1577 <        return val;
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 <    /** Implementation for compute */
743 <    @SuppressWarnings("unchecked")
744 <    private final Object internalCompute(K k,
1583 <                                         RemappingFunction<? super K, V> mf) {
1584 <        int h = spread(k.hashCode());
1585 <        Object val = null;
1586 <        int delta = 0;
1587 <        int count = 0;
1588 <        for (Node[] tab = table;;) {
1589 <            Node f; int i, fh; Object fk;
1590 <            if (tab == null)
1591 <                tab = initTable();
1592 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1593 <                Node node = new Node(fh = h | LOCKED, k, null, null);
1594 <                if (casTabAt(tab, i, null, node)) {
1595 <                    try {
1596 <                        count = 1;
1597 <                        if ((val = mf.remap(k, null)) != null) {
1598 <                            node.val = val;
1599 <                            delta = 1;
1600 <                        }
1601 <                    } finally {
1602 <                        if (delta == 0)
1603 <                            setTabAt(tab, i, null);
1604 <                        if (!node.casHash(fh, h)) {
1605 <                            node.hash = h;
1606 <                            synchronized (node) { node.notifyAll(); };
1607 <                        }
1608 <                    }
1609 <                }
1610 <                if (count != 0)
1611 <                    break;
1612 <            }
1613 <            else if ((fh = f.hash) == MOVED) {
1614 <                if ((fk = f.key) instanceof TreeBin) {
1615 <                    TreeBin t = (TreeBin)fk;
1616 <                    t.acquire(0);
1617 <                    try {
1618 <                        if (tabAt(tab, i) == f) {
1619 <                            count = 1;
1620 <                            TreeNode p = t.getTreeNode(h, k, t.root);
1621 <                            Object pv = (p == null) ? null : p.val;
1622 <                            if ((val = mf.remap(k, (V)pv)) != null) {
1623 <                                if (p != null)
1624 <                                    p.val = val;
1625 <                                else {
1626 <                                    count = 2;
1627 <                                    delta = 1;
1628 <                                    t.putTreeNode(h, k, val);
1629 <                                }
1630 <                            }
1631 <                            else if (p != null) {
1632 <                                delta = -1;
1633 <                                t.deleteTreeNode(p);
1634 <                            }
1635 <                        }
1636 <                    } finally {
1637 <                        t.release(0);
1638 <                    }
1639 <                    if (count != 0)
1640 <                        break;
1641 <                }
1642 <                else
1643 <                    tab = (Node[])fk;
1644 <            }
1645 <            else if ((fh & LOCKED) != 0) {
1646 <                checkForResize();
1647 <                f.tryAwaitLock(tab, i);
1648 <            }
1649 <            else if (f.casHash(fh, fh | LOCKED)) {
1650 <                try {
1651 <                    if (tabAt(tab, i) == f) {
1652 <                        count = 1;
1653 <                        for (Node e = f, pred = null;; ++count) {
1654 <                            Object ek, ev;
1655 <                            if ((e.hash & HASH_BITS) == h &&
1656 <                                (ev = e.val) != null &&
1657 <                                ((ek = e.key) == k || k.equals(ek))) {
1658 <                                val = mf.remap(k, (V)ev);
1659 <                                if (val != null)
1660 <                                    e.val = val;
1661 <                                else {
1662 <                                    delta = -1;
1663 <                                    Node en = e.next;
1664 <                                    if (pred != null)
1665 <                                        pred.next = en;
1666 <                                    else
1667 <                                        setTabAt(tab, i, en);
1668 <                                }
1669 <                                break;
1670 <                            }
1671 <                            pred = e;
1672 <                            if ((e = e.next) == null) {
1673 <                                if ((val = mf.remap(k, null)) != null) {
1674 <                                    pred.next = new Node(h, k, val, null);
1675 <                                    delta = 1;
1676 <                                    if (count >= TREE_THRESHOLD)
1677 <                                        replaceWithTreeBin(tab, i, k);
1678 <                                }
1679 <                                break;
1680 <                            }
1681 <                        }
1682 <                    }
1683 <                } finally {
1684 <                    if (!f.casHash(fh | LOCKED, fh)) {
1685 <                        f.hash = fh;
1686 <                        synchronized (f) { f.notifyAll(); };
1687 <                    }
1688 <                }
1689 <                if (count != 0) {
1690 <                    if (tab.length <= 64)
1691 <                        count = 2;
1692 <                    break;
1693 <                }
1694 <            }
1695 <        }
1696 <        if (delta != 0) {
1697 <            counter.add((long)delta);
1698 <            if (count > 1)
1699 <                checkForResize();
1700 <        }
1701 <        return val;
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 <    /** Implementation for putAll */
748 <    private final void internalPutAll(Map<?, ?> m) {
1706 <        tryPresize(m.size());
1707 <        long delta = 0L;     // number of uncommitted additions
1708 <        boolean npe = false; // to throw exception on exit for nulls
1709 <        try {                // to clean up counts on other exceptions
1710 <            for (Map.Entry<?, ?> entry : m.entrySet()) {
1711 <                Object k, v;
1712 <                if (entry == null || (k = entry.getKey()) == null ||
1713 <                    (v = entry.getValue()) == null) {
1714 <                    npe = true;
1715 <                    break;
1716 <                }
1717 <                int h = spread(k.hashCode());
1718 <                for (Node[] tab = table;;) {
1719 <                    int i; Node f; int fh; Object fk;
1720 <                    if (tab == null)
1721 <                        tab = initTable();
1722 <                    else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1723 <                        if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1724 <                            ++delta;
1725 <                            break;
1726 <                        }
1727 <                    }
1728 <                    else if ((fh = f.hash) == MOVED) {
1729 <                        if ((fk = f.key) instanceof TreeBin) {
1730 <                            TreeBin t = (TreeBin)fk;
1731 <                            boolean validated = false;
1732 <                            t.acquire(0);
1733 <                            try {
1734 <                                if (tabAt(tab, i) == f) {
1735 <                                    validated = true;
1736 <                                    TreeNode p = t.getTreeNode(h, k, t.root);
1737 <                                    if (p != null)
1738 <                                        p.val = v;
1739 <                                    else {
1740 <                                        t.putTreeNode(h, k, v);
1741 <                                        ++delta;
1742 <                                    }
1743 <                                }
1744 <                            } finally {
1745 <                                t.release(0);
1746 <                            }
1747 <                            if (validated)
1748 <                                break;
1749 <                        }
1750 <                        else
1751 <                            tab = (Node[])fk;
1752 <                    }
1753 <                    else if ((fh & LOCKED) != 0) {
1754 <                        counter.add(delta);
1755 <                        delta = 0L;
1756 <                        checkForResize();
1757 <                        f.tryAwaitLock(tab, i);
1758 <                    }
1759 <                    else if (f.casHash(fh, fh | LOCKED)) {
1760 <                        int count = 0;
1761 <                        try {
1762 <                            if (tabAt(tab, i) == f) {
1763 <                                count = 1;
1764 <                                for (Node e = f;; ++count) {
1765 <                                    Object ek, ev;
1766 <                                    if ((e.hash & HASH_BITS) == h &&
1767 <                                        (ev = e.val) != null &&
1768 <                                        ((ek = e.key) == k || k.equals(ek))) {
1769 <                                        e.val = v;
1770 <                                        break;
1771 <                                    }
1772 <                                    Node last = e;
1773 <                                    if ((e = e.next) == null) {
1774 <                                        ++delta;
1775 <                                        last.next = new Node(h, k, v, null);
1776 <                                        if (count >= TREE_THRESHOLD)
1777 <                                            replaceWithTreeBin(tab, i, k);
1778 <                                        break;
1779 <                                    }
1780 <                                }
1781 <                            }
1782 <                        } finally {
1783 <                            if (!f.casHash(fh | LOCKED, fh)) {
1784 <                                f.hash = fh;
1785 <                                synchronized (f) { f.notifyAll(); };
1786 <                            }
1787 <                        }
1788 <                        if (count != 0) {
1789 <                            if (count > 1) {
1790 <                                counter.add(delta);
1791 <                                delta = 0L;
1792 <                                checkForResize();
1793 <                            }
1794 <                            break;
1795 <                        }
1796 <                    }
1797 <                }
1798 <            }
1799 <        } finally {
1800 <            if (delta != 0)
1801 <                counter.add(delta);
1802 <        }
1803 <        if (npe)
1804 <            throw new NullPointerException();
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 <    /* ---------------- Table Initialization and Resizing -------------- */
751 >    /* ---------------- Fields -------------- */
752  
753      /**
754 <     * Returns a power of two table size for the given desired capacity.
755 <     * See Hackers Delight, sec 3.2
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 final int tableSizeFor(int c) {
1814 <        int n = c - 1;
1815 <        n |= n >>> 1;
1816 <        n |= n >>> 2;
1817 <        n |= n >>> 4;
1818 <        n |= n >>> 8;
1819 <        n |= n >>> 16;
1820 <        return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1821 <    }
757 >    transient volatile Node<K,V>[] table;
758  
759      /**
760 <     * Initializes table, using the size recorded in sizeCtl.
760 >     * The next table to use; non-null only while resizing.
761       */
762 <    private final Node[] initTable() {
1827 <        Node[] tab; int sc;
1828 <        while ((tab = table) == null) {
1829 <            if ((sc = sizeCtl) < 0)
1830 <                Thread.yield(); // lost initialization race; just spin
1831 <            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1832 <                try {
1833 <                    if ((tab = table) == null) {
1834 <                        int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1835 <                        tab = table = new Node[n];
1836 <                        sc = n - (n >>> 2);
1837 <                    }
1838 <                } finally {
1839 <                    sizeCtl = sc;
1840 <                }
1841 <                break;
1842 <            }
1843 <        }
1844 <        return tab;
1845 <    }
762 >    private transient volatile Node<K,V>[] nextTable;
763  
764      /**
765 <     * If table is too small and not already resizing, creates next
766 <     * table and transfers bins.  Rechecks occupancy after a transfer
767 <     * to see if another resize is already needed because resizings
1851 <     * are lagging additions.
1852 <     */
1853 <    private final void checkForResize() {
1854 <        Node[] tab; int n, sc;
1855 <        while ((tab = table) != null &&
1856 <               (n = tab.length) < MAXIMUM_CAPACITY &&
1857 <               (sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1858 <               UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1859 <            try {
1860 <                if (tab == table) {
1861 <                    table = rebuild(tab);
1862 <                    sc = (n << 1) - (n >>> 1);
1863 <                }
1864 <            } finally {
1865 <                sizeCtl = sc;
1866 <            }
1867 <        }
1868 <    }
1869 <
1870 <    /**
1871 <     * Tries to presize table to accommodate the given number of elements.
1872 <     *
1873 <     * @param size number of elements (doesn't need to be perfectly accurate)
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 tryPresize(int size) {
1876 <        int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1877 <            tableSizeFor(size + (size >>> 1) + 1);
1878 <        int sc;
1879 <        while ((sc = sizeCtl) >= 0) {
1880 <            Node[] tab = table; int n;
1881 <            if (tab == null || (n = tab.length) == 0) {
1882 <                n = (sc > c) ? sc : c;
1883 <                if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1884 <                    try {
1885 <                        if (table == tab) {
1886 <                            table = new Node[n];
1887 <                            sc = n - (n >>> 2);
1888 <                        }
1889 <                    } finally {
1890 <                        sizeCtl = sc;
1891 <                    }
1892 <                }
1893 <            }
1894 <            else if (c <= sc || n >= MAXIMUM_CAPACITY)
1895 <                break;
1896 <            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1897 <                try {
1898 <                    if (table == tab) {
1899 <                        table = rebuild(tab);
1900 <                        sc = (n << 1) - (n >>> 1);
1901 <                    }
1902 <                } finally {
1903 <                    sizeCtl = sc;
1904 <                }
1905 <            }
1906 <        }
1907 <    }
769 >    private transient volatile long baseCount;
770  
771 <    /*
772 <     * Moves and/or copies the nodes in each bin to new table. See
773 <     * above for explanation.
774 <     *
775 <     * @return the new table
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 static final Node[] rebuild(Node[] tab) {
1916 <        int n = tab.length;
1917 <        Node[] nextTab = new Node[n << 1];
1918 <        Node fwd = new Node(MOVED, nextTab, null, null);
1919 <        int[] buffer = null;       // holds bins to revisit; null until needed
1920 <        Node rev = null;           // reverse forwarder; null until needed
1921 <        int nbuffered = 0;         // the number of bins in buffer list
1922 <        int bufferIndex = 0;       // buffer index of current buffered bin
1923 <        int bin = n - 1;           // current non-buffered bin or -1 if none
1924 <
1925 <        for (int i = bin;;) {      // start upwards sweep
1926 <            int fh; Node f;
1927 <            if ((f = tabAt(tab, i)) == null) {
1928 <                if (bin >= 0) {    // no lock needed (or available)
1929 <                    if (!casTabAt(tab, i, f, fwd))
1930 <                        continue;
1931 <                }
1932 <                else {             // transiently use a locked forwarding node
1933 <                    Node g = new Node(MOVED|LOCKED, nextTab, null, null);
1934 <                    if (!casTabAt(tab, i, f, g))
1935 <                        continue;
1936 <                    setTabAt(nextTab, i, null);
1937 <                    setTabAt(nextTab, i + n, null);
1938 <                    setTabAt(tab, i, fwd);
1939 <                    if (!g.casHash(MOVED|LOCKED, MOVED)) {
1940 <                        g.hash = MOVED;
1941 <                        synchronized (g) { g.notifyAll(); }
1942 <                    }
1943 <                }
1944 <            }
1945 <            else if ((fh = f.hash) == MOVED) {
1946 <                Object fk = f.key;
1947 <                if (fk instanceof TreeBin) {
1948 <                    TreeBin t = (TreeBin)fk;
1949 <                    boolean validated = false;
1950 <                    t.acquire(0);
1951 <                    try {
1952 <                        if (tabAt(tab, i) == f) {
1953 <                            validated = true;
1954 <                            splitTreeBin(nextTab, i, t);
1955 <                            setTabAt(tab, i, fwd);
1956 <                        }
1957 <                    } finally {
1958 <                        t.release(0);
1959 <                    }
1960 <                    if (!validated)
1961 <                        continue;
1962 <                }
1963 <            }
1964 <            else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1965 <                boolean validated = false;
1966 <                try {              // split to lo and hi lists; copying as needed
1967 <                    if (tabAt(tab, i) == f) {
1968 <                        validated = true;
1969 <                        splitBin(nextTab, i, f);
1970 <                        setTabAt(tab, i, fwd);
1971 <                    }
1972 <                } finally {
1973 <                    if (!f.casHash(fh | LOCKED, fh)) {
1974 <                        f.hash = fh;
1975 <                        synchronized (f) { f.notifyAll(); };
1976 <                    }
1977 <                }
1978 <                if (!validated)
1979 <                    continue;
1980 <            }
1981 <            else {
1982 <                if (buffer == null) // initialize buffer for revisits
1983 <                    buffer = new int[TRANSFER_BUFFER_SIZE];
1984 <                if (bin < 0 && bufferIndex > 0) {
1985 <                    int j = buffer[--bufferIndex];
1986 <                    buffer[bufferIndex] = i;
1987 <                    i = j;         // swap with another bin
1988 <                    continue;
1989 <                }
1990 <                if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
1991 <                    f.tryAwaitLock(tab, i);
1992 <                    continue;      // no other options -- block
1993 <                }
1994 <                if (rev == null)   // initialize reverse-forwarder
1995 <                    rev = new Node(MOVED, tab, null, null);
1996 <                if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
1997 <                    continue;      // recheck before adding to list
1998 <                buffer[nbuffered++] = i;
1999 <                setTabAt(nextTab, i, rev);     // install place-holders
2000 <                setTabAt(nextTab, i + n, rev);
2001 <            }
2002 <
2003 <            if (bin > 0)
2004 <                i = --bin;
2005 <            else if (buffer != null && nbuffered > 0) {
2006 <                bin = -1;
2007 <                i = buffer[bufferIndex = --nbuffered];
2008 <            }
2009 <            else
2010 <                return nextTab;
2011 <        }
2012 <    }
779 >    private transient volatile int sizeCtl;
780  
781      /**
782 <     * Split a normal bin with list headed by e into lo and hi parts;
2016 <     * install in given table
782 >     * The next table index (plus one) to split while resizing.
783       */
784 <    private static void splitBin(Node[] nextTab, int i, Node e) {
2019 <        int bit = nextTab.length >>> 1; // bit to split on
2020 <        int runBit = e.hash & bit;
2021 <        Node lastRun = e, lo = null, hi = null;
2022 <        for (Node p = e.next; p != null; p = p.next) {
2023 <            int b = p.hash & bit;
2024 <            if (b != runBit) {
2025 <                runBit = b;
2026 <                lastRun = p;
2027 <            }
2028 <        }
2029 <        if (runBit == 0)
2030 <            lo = lastRun;
2031 <        else
2032 <            hi = lastRun;
2033 <        for (Node p = e; p != lastRun; p = p.next) {
2034 <            int ph = p.hash & HASH_BITS;
2035 <            Object pk = p.key, pv = p.val;
2036 <            if ((ph & bit) == 0)
2037 <                lo = new Node(ph, pk, pv, lo);
2038 <            else
2039 <                hi = new Node(ph, pk, pv, hi);
2040 <        }
2041 <        setTabAt(nextTab, i, lo);
2042 <        setTabAt(nextTab, i + bit, hi);
2043 <    }
784 >    private transient volatile int transferIndex;
785  
786      /**
787 <     * Split a tree bin into lo and hi parts; install in given table
787 >     * The least available table index to split while resizing.
788       */
789 <    private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
2049 <        int bit = nextTab.length >>> 1;
2050 <        TreeBin lt = new TreeBin();
2051 <        TreeBin ht = new TreeBin();
2052 <        int lc = 0, hc = 0;
2053 <        for (Node e = t.first; e != null; e = e.next) {
2054 <            int h = e.hash & HASH_BITS;
2055 <            Object k = e.key, v = e.val;
2056 <            if ((h & bit) == 0) {
2057 <                ++lc;
2058 <                lt.putTreeNode(h, k, v);
2059 <            }
2060 <            else {
2061 <                ++hc;
2062 <                ht.putTreeNode(h, k, v);
2063 <            }
2064 <        }
2065 <        Node ln, hn; // throw away trees if too small
2066 <        if (lc <= (TREE_THRESHOLD >>> 1)) {
2067 <            ln = null;
2068 <            for (Node p = lt.first; p != null; p = p.next)
2069 <                ln = new Node(p.hash, p.key, p.val, ln);
2070 <        }
2071 <        else
2072 <            ln = new Node(MOVED, lt, null, null);
2073 <        setTabAt(nextTab, i, ln);
2074 <        if (hc <= (TREE_THRESHOLD >>> 1)) {
2075 <            hn = null;
2076 <            for (Node p = ht.first; p != null; p = p.next)
2077 <                hn = new Node(p.hash, p.key, p.val, hn);
2078 <        }
2079 <        else
2080 <            hn = new Node(MOVED, ht, null, null);
2081 <        setTabAt(nextTab, i + bit, hn);
2082 <    }
789 >    private transient volatile int transferOrigin;
790  
791      /**
792 <     * Implementation for clear. Steps through each bin, removing all
2086 <     * nodes.
792 >     * Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
793       */
794 <    private final void internalClear() {
2089 <        long delta = 0L; // negative number of deletions
2090 <        int i = 0;
2091 <        Node[] tab = table;
2092 <        while (tab != null && i < tab.length) {
2093 <            int fh; Object fk;
2094 <            Node f = tabAt(tab, i);
2095 <            if (f == null)
2096 <                ++i;
2097 <            else if ((fh = f.hash) == MOVED) {
2098 <                if ((fk = f.key) instanceof TreeBin) {
2099 <                    TreeBin t = (TreeBin)fk;
2100 <                    t.acquire(0);
2101 <                    try {
2102 <                        if (tabAt(tab, i) == f) {
2103 <                            for (Node p = t.first; p != null; p = p.next) {
2104 <                                p.val = null;
2105 <                                --delta;
2106 <                            }
2107 <                            t.first = null;
2108 <                            t.root = null;
2109 <                            ++i;
2110 <                        }
2111 <                    } finally {
2112 <                        t.release(0);
2113 <                    }
2114 <                }
2115 <                else
2116 <                    tab = (Node[])fk;
2117 <            }
2118 <            else if ((fh & LOCKED) != 0) {
2119 <                counter.add(delta); // opportunistically update count
2120 <                delta = 0L;
2121 <                f.tryAwaitLock(tab, i);
2122 <            }
2123 <            else if (f.casHash(fh, fh | LOCKED)) {
2124 <                try {
2125 <                    if (tabAt(tab, i) == f) {
2126 <                        for (Node e = f; e != null; e = e.next) {
2127 <                            e.val = null;
2128 <                            --delta;
2129 <                        }
2130 <                        setTabAt(tab, i, null);
2131 <                        ++i;
2132 <                    }
2133 <                } finally {
2134 <                    if (!f.casHash(fh | LOCKED, fh)) {
2135 <                        f.hash = fh;
2136 <                        synchronized (f) { f.notifyAll(); };
2137 <                    }
2138 <                }
2139 <            }
2140 <        }
2141 <        if (delta != 0)
2142 <            counter.add(delta);
2143 <    }
2144 <
2145 <    /* ----------------Table Traversal -------------- */
794 >    private transient volatile int cellsBusy;
795  
796      /**
797 <     * Encapsulates traversal for methods such as containsValue; also
2149 <     * serves as a base class for other iterators.
2150 <     *
2151 <     * At each step, the iterator snapshots the key ("nextKey") and
2152 <     * value ("nextVal") of a valid node (i.e., one that, at point of
2153 <     * snapshot, has a non-null user value). Because val fields can
2154 <     * change (including to null, indicating deletion), field nextVal
2155 <     * might not be accurate at point of use, but still maintains the
2156 <     * weak consistency property of holding a value that was once
2157 <     * valid.
2158 <     *
2159 <     * Internal traversals directly access these fields, as in:
2160 <     * {@code while (it.advance() != null) { process(it.nextKey); }}
2161 <     *
2162 <     * Exported iterators must track whether the iterator has advanced
2163 <     * (in hasNext vs next) (by setting/checking/nulling field
2164 <     * nextVal), and then extract key, value, or key-value pairs as
2165 <     * return values of next().
2166 <     *
2167 <     * The iterator visits once each still-valid node that was
2168 <     * reachable upon iterator construction. It might miss some that
2169 <     * were added to a bin after the bin was visited, which is OK wrt
2170 <     * consistency guarantees. Maintaining this property in the face
2171 <     * of possible ongoing resizes requires a fair amount of
2172 <     * bookkeeping state that is difficult to optimize away amidst
2173 <     * volatile accesses.  Even so, traversal maintains reasonable
2174 <     * throughput.
2175 <     *
2176 <     * Normally, iteration proceeds bin-by-bin traversing lists.
2177 <     * However, if the table has been resized, then all future steps
2178 <     * must traverse both the bin at the current index as well as at
2179 <     * (index + baseSize); and so on for further resizings. To
2180 <     * paranoically cope with potential sharing by users of iterators
2181 <     * across threads, iteration terminates if a bounds checks fails
2182 <     * for a table read.
797 >     * Table of counter cells. When non-null, size is a power of 2.
798       */
799 <    static class InternalIterator<K,V> {
2185 <        final ConcurrentHashMapV8<K, V> map;
2186 <        Node next;           // the next entry to use
2187 <        Node last;           // the last entry used
2188 <        Object nextKey;      // cached key field of next
2189 <        Object nextVal;      // cached val field of next
2190 <        Node[] tab;          // current table; updated if resized
2191 <        int index;           // index of bin to use next
2192 <        int baseIndex;       // current index of initial table
2193 <        int baseLimit;       // index bound for initial table
2194 <        final int baseSize;  // initial table size
2195 <
2196 <        /** Creates iterator for all entries in the table. */
2197 <        InternalIterator(ConcurrentHashMapV8<K, V> map) {
2198 <            this.tab = (this.map = map).table;
2199 <            baseLimit = baseSize = (tab == null) ? 0 : tab.length;
2200 <        }
2201 <
2202 <        /** Creates iterator for clone() and split() methods */
2203 <        InternalIterator(InternalIterator<K,V> it, boolean split) {
2204 <            this.map = it.map;
2205 <            this.tab = it.tab;
2206 <            this.baseSize = it.baseSize;
2207 <            int lo = it.baseIndex;
2208 <            int hi = this.baseLimit = it.baseLimit;
2209 <            this.index = this.baseIndex =
2210 <                (split) ? (it.baseLimit = (lo + hi + 1) >>> 1) : lo;
2211 <        }
2212 <
2213 <        /**
2214 <         * Advances next; returns nextVal or null if terminated
2215 <         * See above for explanation.
2216 <         */
2217 <        final Object advance() {
2218 <            Node e = last = next;
2219 <            Object ev = null;
2220 <            outer: do {
2221 <                if (e != null)                  // advance past used/skipped node
2222 <                    e = e.next;
2223 <                while (e == null) {             // get to next non-null bin
2224 <                    Node[] t; int b, i, n; Object ek; // checks must use locals
2225 <                    if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2226 <                        (t = tab) == null || i >= (n = t.length))
2227 <                        break outer;
2228 <                    else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2229 <                        if ((ek = e.key) instanceof TreeBin)
2230 <                            e = ((TreeBin)ek).first;
2231 <                        else {
2232 <                            tab = (Node[])ek;
2233 <                            continue;           // restarts due to null val
2234 <                        }
2235 <                    }                           // visit upper slots if present
2236 <                    index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2237 <                }
2238 <                nextKey = e.key;
2239 <            } while ((ev = e.val) == null);    // skip deleted or special nodes
2240 <            next = e;
2241 <            return nextVal = ev;
2242 <        }
2243 <
2244 <        public final void remove() {
2245 <            if (nextVal == null)
2246 <                advance();
2247 <            Node e = last;
2248 <            if (e == null)
2249 <                throw new IllegalStateException();
2250 <            last = null;
2251 <            map.remove(e.key);
2252 <        }
799 >    private transient volatile CounterCell[] counterCells;
800  
801 <        public final boolean hasNext() {
802 <            return nextVal != null || advance() != null;
803 <        }
801 >    // views
802 >    private transient KeySetView<K,V> keySet;
803 >    private transient ValuesView<K,V> values;
804 >    private transient EntrySetView<K,V> entrySet;
805  
2258        public final boolean hasMoreElements() { return hasNext(); }
2259    }
806  
807      /* ---------------- Public operations -------------- */
808  
809      /**
810 <     * Creates a new, empty map with the default initial table size (16),
810 >     * Creates a new, empty map with the default initial table size (16).
811       */
812      public ConcurrentHashMapV8() {
2267        this.counter = new LongAdder();
813      }
814  
815      /**
# Line 2283 | Line 828 | public class ConcurrentHashMapV8<K, V>
828          int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
829                     MAXIMUM_CAPACITY :
830                     tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2286        this.counter = new LongAdder();
831          this.sizeCtl = cap;
832      }
833  
# Line 2293 | Line 837 | public class ConcurrentHashMapV8<K, V>
837       * @param m the map
838       */
839      public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2296        this.counter = new LongAdder();
840          this.sizeCtl = DEFAULT_CAPACITY;
841 <        internalPutAll(m);
841 >        putAll(m);
842      }
843  
844      /**
# Line 2336 | 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
886              initialCapacity = concurrencyLevel;   // as estimated threads
887          long size = (long)(1.0 + (long)initialCapacity / loadFactor);
888 <        int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
889 <                   MAXIMUM_CAPACITY: tableSizeFor((int)size));
2347 <        this.counter = new LongAdder();
888 >        int cap = (size >= (long)MAXIMUM_CAPACITY) ?
889 >            MAXIMUM_CAPACITY : tableSizeFor((int)size);
890          this.sizeCtl = cap;
891      }
892  
893 <    /**
2352 <     * {@inheritDoc}
2353 <     */
2354 <    public boolean isEmpty() {
2355 <        return counter.sum() <= 0L; // ignore transient negative values
2356 <    }
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 <    final long longSize() { // accurate version of size needed for views
906 <        long n = counter.sum();
907 <        return (n < 0L) ? 0L : n;
905 >    /**
906 >     * {@inheritDoc}
907 >     */
908 >    public boolean isEmpty() {
909 >        return sumCount() <= 0L; // ignore transient negative values
910      }
911  
912      /**
# Line 2381 | Line 920 | public class ConcurrentHashMapV8<K, V>
920       *
921       * @throws NullPointerException if the specified key is null
922       */
2384    @SuppressWarnings("unchecked")
923      public V get(Object key) {
924 <        if (key == null)
925 <            throw new NullPointerException();
926 <        return (V)internalGet(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)
2402 <            throw new NullPointerException();
2403 <        return internalGet(key) != null;
953 >        return get(key) != null;
954      }
955  
956      /**
# Line 2416 | 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 <        InternalIterator<K,V> it = new InternalIterator<K,V>(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      /**
2429     * Legacy method testing if some key maps into the specified value
2430     * in this table.  This method is identical in functionality to
2431     * {@link #containsValue}, and exists solely to ensure
2432     * full compatibility with class {@link java.util.Hashtable},
2433     * which supported this method prior to introduction of the
2434     * Java Collections framework.
2435     *
2436     * @param  value a value to search for
2437     * @return {@code true} if and only if some key maps to the
2438     *         {@code value} argument in this table as
2439     *         determined by the {@code equals} method;
2440     *         {@code false} otherwise
2441     * @throws NullPointerException if the specified value is null
2442     */
2443    public boolean contains(Object value) {
2444        return containsValue(value);
2445    }
2446
2447    /**
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 2457 | 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       */
2460    @SuppressWarnings("unchecked")
994      public V put(K key, V value) {
995 <        if (key == null || value == null)
2463 <            throw new NullPointerException();
2464 <        return (V)internalPut(key, 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")
1006 <    public V putIfAbsent(K key, V value) {
1007 <        if (key == null || value == null)
1008 <            throw new NullPointerException();
1009 <        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 2486 | 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 <
2492 <    /**
2493 <     * If the specified key is not already associated with a value,
2494 <     * computes its value using the given mappingFunction and enters
2495 <     * it into the map unless null.  This is equivalent to
2496 <     * <pre> {@code
2497 <     * if (map.containsKey(key))
2498 <     *   return map.get(key);
2499 <     * value = mappingFunction.map(key);
2500 <     * if (value != null)
2501 <     *   map.put(key, value);
2502 <     * return value;}</pre>
2503 <     *
2504 <     * except that the action is performed atomically.  If the
2505 <     * function returns {@code null} no mapping is recorded. If the
2506 <     * function itself throws an (unchecked) exception, the exception
2507 <     * is rethrown to its caller, and no mapping is recorded.  Some
2508 <     * attempted update operations on this map by other threads may be
2509 <     * blocked while computation is in progress, so the computation
2510 <     * should be short and simple, and must not attempt to update any
2511 <     * other mappings of this Map. The most appropriate usage is to
2512 <     * construct a new object serving as an initial mapped value, or
2513 <     * memoized result, as in:
2514 <     *
2515 <     *  <pre> {@code
2516 <     * map.computeIfAbsent(key, new MappingFunction<K, V>() {
2517 <     *   public V map(K k) { return new Value(f(k)); }});}</pre>
2518 <     *
2519 <     * @param key key with which the specified value is to be associated
2520 <     * @param mappingFunction the function to compute a value
2521 <     * @return the current (existing or computed) value associated with
2522 <     *         the specified key, or null if the computed value is null.
2523 <     * @throws NullPointerException if the specified key or mappingFunction
2524 <     *         is null
2525 <     * @throws IllegalStateException if the computation detectably
2526 <     *         attempts a recursive update to this map that would
2527 <     *         otherwise never complete
2528 <     * @throws RuntimeException or Error if the mappingFunction does so,
2529 <     *         in which case the mapping is left unestablished
2530 <     */
2531 <    @SuppressWarnings("unchecked")
2532 <    public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2533 <        if (key == null || mappingFunction == null)
2534 <            throw new NullPointerException();
2535 <        return (V)internalComputeIfAbsent(key, mappingFunction);
2536 <    }
2537 <
2538 <    /**
2539 <     * Computes a new mapping value given a key and
2540 <     * its current mapped value (or {@code null} if there is no current
2541 <     * mapping). This is equivalent to
2542 <     *  <pre> {@code
2543 <     *   value = remappingFunction.remap(key, map.get(key));
2544 <     *   if (value != null)
2545 <     *     map.put(key, value);
2546 <     *   else
2547 <     *     map.remove(key);
2548 <     * }</pre>
2549 <     *
2550 <     * except that the action is performed atomically.  If the
2551 <     * function returns {@code null}, the mapping is removed.  If the
2552 <     * function itself throws an (unchecked) exception, the exception
2553 <     * is rethrown to its caller, and the current mapping is left
2554 <     * unchanged.  Some attempted update operations on this map by
2555 <     * other threads may be blocked while computation is in progress,
2556 <     * so the computation should be short and simple, and must not
2557 <     * attempt to update any other mappings of this Map. For example,
2558 <     * to either create or append new messages to a value mapping:
2559 <     *
2560 <     * <pre> {@code
2561 <     * Map<Key, String> map = ...;
2562 <     * final String msg = ...;
2563 <     * map.compute(key, new RemappingFunction<Key, String>() {
2564 <     *   public String remap(Key k, String v) {
2565 <     *    return (v == null) ? msg : v + msg;});}}</pre>
2566 <     *
2567 <     * @param key key with which the specified value is to be associated
2568 <     * @param remappingFunction the function to compute a value
2569 <     * @return the new value associated with
2570 <     *         the specified key, or null if none.
2571 <     * @throws NullPointerException if the specified key or remappingFunction
2572 <     *         is null
2573 <     * @throws IllegalStateException if the computation detectably
2574 <     *         attempts a recursive update to this map that would
2575 <     *         otherwise never complete
2576 <     * @throws RuntimeException or Error if the remappingFunction does so,
2577 <     *         in which case the mapping is unchanged
2578 <     */
2579 <    @SuppressWarnings("unchecked")
2580 <    public V compute(K key, RemappingFunction<? super K, V> remappingFunction) {
2581 <        if (key == null || remappingFunction == null)
2582 <            throw new NullPointerException();
2583 <        return (V)internalCompute(key, 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 2592 | 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       */
2595    @SuppressWarnings("unchecked")
1085      public V remove(Object key) {
1086 <        if (key == null)
2598 <            throw new NullPointerException();
2599 <        return (V)internalReplace(key, null, null);
2600 <    }
2601 <
2602 <    /**
2603 <     * {@inheritDoc}
2604 <     *
2605 <     * @throws NullPointerException if the specified key is null
2606 <     */
2607 <    public boolean remove(Object key, Object value) {
2608 <        if (key == null)
2609 <            throw new NullPointerException();
2610 <        if (value == null)
2611 <            return false;
2612 <        return internalReplace(key, null, value) != null;
2613 <    }
2614 <
2615 <    /**
2616 <     * {@inheritDoc}
2617 <     *
2618 <     * @throws NullPointerException if any of the arguments are null
2619 <     */
2620 <    public boolean replace(K key, V oldValue, V newValue) {
2621 <        if (key == null || oldValue == null || newValue == null)
2622 <            throw new NullPointerException();
2623 <        return internalReplace(key, newValue, oldValue) != null;
1086 >        return replaceNode(key, null, null);
1087      }
1088  
1089      /**
1090 <     * {@inheritDoc}
1091 <     *
1092 <     * @return the previous value associated with the specified key,
2630 <     *         or {@code null} if there was no mapping for the key
2631 <     * @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")
1095 <    public V replace(K key, V value) {
1096 <        if (key == null || value == null)
1097 <            throw new NullPointerException();
1098 <        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 2659 | 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 2680 | 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 2693 | 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
2697 <     * {@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.
2704     */
2705    public Set<Map.Entry<K,V>> entrySet() {
2706        EntrySet<K,V> es = entrySet;
2707        return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
2708    }
2709
2710    /**
2711     * Returns an enumeration of the keys in this table.
1260       *
1261 <     * @return an enumeration of the keys in this table
2714 <     * @see #keySet()
1261 >     * @return the set view
1262       */
1263 <    public Enumeration<K> keys() {
1264 <        return new KeyIterator<K,V>(this);
1265 <    }
2719 <
2720 <    /**
2721 <     * Returns an enumeration of the values in this table.
2722 <     *
2723 <     * @return an enumeration of the values in this table
2724 <     * @see #values()
2725 <     */
2726 <    public Enumeration<V> elements() {
2727 <        return new ValueIterator<K,V>(this);
2728 <    }
2729 <
2730 <    /**
2731 <     * Returns a partionable iterator of the keys in this map.
2732 <     *
2733 <     * @return a partionable iterator of the keys in this map
2734 <     */
2735 <    public Spliterator<K> keySpliterator() {
2736 <        return new KeyIterator<K,V>(this);
2737 <    }
2738 <
2739 <    /**
2740 <     * Returns a partionable iterator of the values in this map.
2741 <     *
2742 <     * @return a partionable iterator of the values in this map
2743 <     */
2744 <    public Spliterator<V> valueSpliterator() {
2745 <        return new ValueIterator<K,V>(this);
2746 <    }
2747 <
2748 <    /**
2749 <     * Returns a partionable iterator of the entries in this map.
2750 <     *
2751 <     * @return a partionable iterator of the entries in this map
2752 <     */
2753 <    public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2754 <        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 2763 | Line 1274 | public class ConcurrentHashMapV8<K, V>
1274       */
1275      public int hashCode() {
1276          int h = 0;
1277 <        InternalIterator<K,V> it = new InternalIterator<K,V>(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 2783 | Line 1295 | public class ConcurrentHashMapV8<K, V>
1295       * @return a string representation of this map
1296       */
1297      public String toString() {
1298 <        InternalIterator<K,V> it = new InternalIterator<K,V>(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 2816 | Line 1331 | public class ConcurrentHashMapV8<K, V>
1331              if (!(o instanceof Map))
1332                  return false;
1333              Map<?,?> m = (Map<?,?>) o;
1334 <            InternalIterator<K,V> it = new InternalIterator<K,V>(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 2827 | 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 2835 | 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 <    static final class KeyIterator<K,V> extends InternalIterator<K,V>
1366 <        implements Spliterator<K>, Enumeration<K> {
1367 <        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1368 <        KeyIterator(InternalIterator<K,V> it, boolean split) {
1369 <            super(it, split);
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 <        public KeyIterator<K,V> split() {
1404 <            if (last != null || (next != null && nextVal == null))
1405 <                throw new IllegalStateException();
1406 <            return new KeyIterator<K,V>(this, true);
1403 >        s.writeObject(null);
1404 >        s.writeObject(null);
1405 >        segments = null; // throw away
1406 >    }
1407 >
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 <        public KeyIterator<K,V> clone() {
1436 <            if (last != null || (next != null && nextVal == null))
1437 <                throw new IllegalStateException();
1438 <            return new KeyIterator<K,V>(this, false);
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          }
1505 +    }
1506  
1507 <        @SuppressWarnings("unchecked")
1508 <        public final K next() {
1509 <            if (nextVal == null && advance() == null)
1510 <                throw new NoSuchElementException();
1511 <            Object k = nextKey;
1512 <            nextVal = null;
1513 <            return (K) k;
1507 >    // ConcurrentMap methods
1508 >
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 >     * {@inheritDoc}
1522 >     *
1523 >     * @throws NullPointerException if the specified key is null
1524 >     */
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 >    /**
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 >     * {@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 >    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 >    // Overrides of JDK8+ Map extension method defaults
1556 >
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 K nextElement() { return next(); }
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 >                }
1599 >            }
1600 >        }
1601      }
1602  
1603 <    static final class ValueIterator<K,V> extends InternalIterator<K,V>
1604 <        implements Spliterator<V>, Enumeration<V> {
1605 <        ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1606 <        ValueIterator(InternalIterator<K,V> it, boolean split) {
1607 <            super(it, split);
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 >                if (binCount != 0)
1650 >                    break;
1651 >            }
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 >            }
1700          }
1701 <        public ValueIterator<K,V> split() {
1702 <            if (last != null || (next != null && nextVal == null))
1703 <                throw new IllegalStateException();
1704 <            return new ValueIterator<K,V>(this, true);
1701 >        if (val != null)
1702 >            addCount(1L, binCount);
1703 >        return val;
1704 >    }
1705 >
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 >            }
1790 >        }
1791 >        if (delta != 0)
1792 >            addCount((long)delta, binCount);
1793 >        return val;
1794 >    }
1795 >
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 >            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 >            }
1916 >        }
1917 >        if (delta != 0)
1918 >            addCount((long)delta, binCount);
1919 >        return val;
1920 >    }
1921 >
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 >            }
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 >    /**
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 >    // 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 >            }
2174 >        }
2175 >    }
2176 >
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 >
2185 >        Node<K,V> find(int h, Object k) {
2186 >            return null;
2187 >        }
2188 >    }
2189 >
2190 >    /* ---------------- Table Initialization and Resizing -------------- */
2191 >
2192 >    /**
2193 >     * Initializes table, using the size recorded in sizeCtl.
2194 >     */
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 >     * 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 >        }
2262 >    }
2263 >
2264 >    /**
2265 >     * Helps transfer if a resize is in progress.
2266 >     */
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 >    /**
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 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 >    }
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 >                    }
2381 >                }
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 >            }
2464 >        }
2465 >    }
2466 >
2467 >    /* ---------------- Conversion from/to TreeBins -------------- */
2468 >
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 a list on non-TreeNodes replacing those in given list.
2504 >     */
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 >     * Nodes for use in TreeBins
2522 >     */
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 >        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 >        Node<K,V> find(int h, Object k) {
2537 >            return findTreeNode(h, k, null);
2538 >        }
2539 >
2540 >        /**
2541 >         * Returns the TreeNode (or null if not found) for the given key
2542 >         * starting at given root.
2543 >         */
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 >    /* ---------------- 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 >         * 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 >         * Acquires write lock for tree restructuring.
2659 >         */
2660 >        private final void lockRoot() {
2661 >            if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2662 >                contendedLock(); // offload to separate method
2663 >        }
2664 >
2665 >        /**
2666 >         * Releases write lock for tree restructuring.
2667 >         */
2668 >        private final void unlockRoot() {
2669 >            lockState = 0;
2670 >        }
2671 >
2672 >        /**
2673 >         * Possibly blocks awaiting root lock.
2674 >         */
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 >         * 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 > 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 >         * Finds or adds a node.
2734 >         * @return null if added
2735 >         */
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 >         * 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 >         * @return true if now too small, so should be untreeified
2802 >         */
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 >        // 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 >        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 >        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 >        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 >         * Recursive invariant check
3087 >         */
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 >        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 >    /* ----------------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 <        public ValueIterator<K,V> clone() {
3164 <            if (last != null || (next != null && nextVal == null))
3163 >        /**
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 >     * 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 >        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 <            return new ValueIterator<K,V>(this, false);
3215 >            lastReturned = null;
3216 >            map.replaceNode(p.key, null, null);
3217          }
3218 +    }
3219  
3220 <        @SuppressWarnings("unchecked")
3221 <        public final V next() {
3222 <            Object v;
3223 <            if ((v = nextVal) == null && (v = advance()) == null)
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 >        public final K next() {
3228 >            Node<K,V> p;
3229 >            if ((p = next) == null)
3230                  throw new NoSuchElementException();
3231 <            nextVal = null;
3232 <            return (V) v;
3231 >            K k = p.key;
3232 >            lastReturned = p;
3233 >            advance();
3234 >            return k;
3235          }
3236  
3237 <        public final V nextElement() { return next(); }
3237 >        public final K nextElement() { return next(); }
3238      }
3239  
3240 <    static final class EntryIterator<K,V> extends InternalIterator<K,V>
3241 <        implements Spliterator<Map.Entry<K,V>> {
3242 <        EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3243 <        EntryIterator(InternalIterator<K,V> it, boolean split) {
3244 <            super(it, split);
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 <        public EntryIterator<K,V> split() {
3247 <            if (last != null || (next != null && nextVal == null))
3248 <                throw new IllegalStateException();
3249 <            return new EntryIterator<K,V>(this, true);
3246 >
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 <        public EntryIterator<K,V> clone() {
3257 <            if (last != null || (next != null && nextVal == null))
3258 <                throw new IllegalStateException();
3259 <            return new EntryIterator<K,V>(this, false);
3256 >
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  
2916        @SuppressWarnings("unchecked")
3267          public final Map.Entry<K,V> next() {
3268 <            Object v;
3269 <            if ((v = nextVal) == null && (v = advance()) == null)
3268 >            Node<K,V> p;
3269 >            if ((p = next) == null)
3270                  throw new NoSuchElementException();
3271 <            Object k = nextKey;
3272 <            nextVal = null;
3273 <            return new MapEntry<K,V>((K)k, (V)v, map);
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 <     * Exported Entry for iterators
3280 >     * Exported Entry for EntryIterator
3281       */
3282 <    static final class MapEntry<K,V> implements Map.Entry<K, V> {
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) {
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 final K getKey()       { return key; }
3292 <        public final V getValue()     { return val; }
3293 <        public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3294 <        public final String toString(){ return key + "=" + val; }
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 <        public final boolean equals(Object o) {
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 &&
# Line 2952 | Line 3304 | public class ConcurrentHashMapV8<K, V>
3304  
3305          /**
3306           * Sets our entry's value and writes through to the map. The
3307 <         * value to return is somewhat arbitrary here. Since a we do
3308 <         * not necessarily track asynchronous changes, the most recent
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
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 final V setValue(V value) {
3313 >        public V setValue(V value) {
3314              if (value == null) throw new NullPointerException();
3315              V v = val;
3316              val = value;
# Line 2967 | Line 3319 | public class ConcurrentHashMapV8<K, V>
3319          }
3320      }
3321  
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 +        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 +    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 +        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 +        public void forEachRemaining(Action<? super V> action) {
3374 +            if (action == null) throw new NullPointerException();
3375 +            for (Node<K,V> p; (p = advance()) != null;)
3376 +                action.apply(p.val);
3377 +        }
3378 +
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 +        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 +        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 +        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 +        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 <    static abstract class MapView<K, V> {
4165 <        final ConcurrentHashMapV8<K, V> map;
4166 <        MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
4167 <        public final int size()                 { return map.size(); }
4168 <        public final boolean isEmpty()          { return map.isEmpty(); }
4169 <        public final void clear()               { map.clear(); }
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 the map backing this view.
4172 >         *
4173 >         * @return the map backing this view
4174 >         */
4175 >        public ConcurrentHashMapV8<K,V> getMap() { return map; }
4176 >
4177 >        /**
4178 >         * Removes all of the elements from this view, by removing all
4179 >         * the mappings from the map backing this view.
4180 >         */
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 public Iterator<?> iterator();
4187 <        abstract public boolean contains(Object o);
4188 <        abstract public boolean remove(Object o);
4186 >        // abstract methods
4187 >        /**
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.longSize();
4203 <            if (sz > (long)(MAX_ARRAY_SIZE))
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 <            Iterator<?> it = iterator();
2997 <            while (it.hasNext()) {
4208 >            for (E e : this) {
4209                  if (i == n) {
4210                      if (n >= MAX_ARRAY_SIZE)
4211                          throw new OutOfMemoryError(oomeMsg);
# Line 3004 | Line 4215 | public class ConcurrentHashMapV8<K, V>
4215                          n += (n >>> 1) + 1;
4216                      r = Arrays.copyOf(r, n);
4217                  }
4218 <                r[i++] = it.next();
4218 >                r[i++] = e;
4219              }
4220              return (i == n) ? r : Arrays.copyOf(r, i);
4221          }
4222  
4223          @SuppressWarnings("unchecked")
4224          public final <T> T[] toArray(T[] a) {
4225 <            long sz = map.longSize();
4226 <            if (sz > (long)(MAX_ARRAY_SIZE))
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 :
# Line 3020 | Line 4231 | public class ConcurrentHashMapV8<K, V>
4231                  .newInstance(a.getClass().getComponentType(), m);
4232              int n = r.length;
4233              int i = 0;
4234 <            Iterator<?> it = iterator();
3024 <            while (it.hasNext()) {
4234 >            for (E e : this) {
4235                  if (i == n) {
4236                      if (n >= MAX_ARRAY_SIZE)
4237                          throw new OutOfMemoryError(oomeMsg);
# Line 3031 | Line 4241 | public class ConcurrentHashMapV8<K, V>
4241                          n += (n >>> 1) + 1;
4242                      r = Arrays.copyOf(r, n);
4243                  }
4244 <                r[i++] = (T)it.next();
4244 >                r[i++] = (T)e;
4245              }
4246              if (a == r && i < n) {
4247                  r[i] = null; // null-terminate
# Line 3040 | Line 4250 | public class ConcurrentHashMapV8<K, V>
4250              return (i == n) ? r : Arrays.copyOf(r, i);
4251          }
4252  
4253 <        public final int hashCode() {
4254 <            int h = 0;
4255 <            for (Iterator<?> it = iterator(); it.hasNext();)
4256 <                h += it.next().hashCode();
4257 <            return h;
4258 <        }
4259 <
4253 >        /**
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 >         * @return a string representation of this collection
4263 >         */
4264          public final String toString() {
4265              StringBuilder sb = new StringBuilder();
4266              sb.append('[');
4267 <            Iterator<?> it = iterator();
4267 >            Iterator<E> it = iterator();
4268              if (it.hasNext()) {
4269                  for (;;) {
4270                      Object e = it.next();
# Line 3065 | Line 4279 | public class ConcurrentHashMapV8<K, V>
4279  
4280          public final boolean containsAll(Collection<?> c) {
4281              if (c != this) {
4282 <                for (Iterator<?> it = c.iterator(); it.hasNext();) {
3069 <                    Object e = it.next();
4282 >                for (Object e : c) {
4283                      if (e == null || !contains(e))
4284                          return false;
4285                  }
# Line 3076 | Line 4289 | public class ConcurrentHashMapV8<K, V>
4289  
4290          public final boolean removeAll(Collection<?> c) {
4291              boolean modified = false;
4292 <            for (Iterator<?> it = iterator(); it.hasNext();) {
4292 >            for (Iterator<E> it = iterator(); it.hasNext();) {
4293                  if (c.contains(it.next())) {
4294                      it.remove();
4295                      modified = true;
# Line 3087 | Line 4300 | public class ConcurrentHashMapV8<K, V>
4300  
4301          public final boolean retainAll(Collection<?> c) {
4302              boolean modified = false;
4303 <            for (Iterator<?> it = iterator(); it.hasNext();) {
4303 >            for (Iterator<E> it = iterator(); it.hasNext();) {
4304                  if (!c.contains(it.next())) {
4305                      it.remove();
4306                      modified = true;
# Line 3098 | Line 4311 | public class ConcurrentHashMapV8<K, V>
4311  
4312      }
4313  
4314 <    static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
4315 <        KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
4316 <        public final boolean contains(Object o) { return map.containsKey(o); }
4317 <        public final boolean remove(Object o)   { return map.remove(o) != null; }
4318 <        public final Iterator<K> iterator() {
4319 <            return new KeyIterator<K,V>(map);
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 <        public final boolean add(K e) {
4334 <            throw new UnsupportedOperationException();
4333 >
4334 >        /**
4335 >         * Returns the default mapped value for additions,
4336 >         * or {@code null} if additions are not supported.
4337 >         *
4338 >         * @return the default mapped value for additions, or {@code null}
4339 >         * if not supported
4340 >         */
4341 >        public V getMappedValue() { return value; }
4342 >
4343 >        /**
4344 >         * {@inheritDoc}
4345 >         * @throws NullPointerException if the specified key is null
4346 >         */
4347 >        public boolean contains(Object o) { return map.containsKey(o); }
4348 >
4349 >        /**
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 boolean remove(Object o) { return map.remove(o) != null; }
4359 >
4360 >        /**
4361 >         * @return an iterator over the keys of the backing map
4362 >         */
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 <        public final boolean addAll(Collection<? extends K> c) {
4370 <            throw new UnsupportedOperationException();
4369 >
4370 >        /**
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 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 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 >         * 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 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 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 +        public int hashCode() {
4411 +            int h = 0;
4412 +            for (K e : this)
4413 +                h += e.hashCode();
4414 +            return h;
4415 +        }
4416 +
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 +        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 +        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 <    static final class Values<K,V> extends MapView<K,V>
4444 <        implements Collection<V> {
4445 <        Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
4446 <        public final boolean contains(Object o) { return map.containsValue(o); }
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          public final boolean remove(Object o) {
4457              if (o != null) {
4458 <                Iterator<V> it = new ValueIterator<K,V>(map);
3129 <                while (it.hasNext()) {
4458 >                for (Iterator<V> it = iterator(); it.hasNext();) {
4459                      if (o.equals(it.next())) {
4460                          it.remove();
4461                          return true;
# Line 3135 | Line 4464 | public class ConcurrentHashMapV8<K, V>
4464              }
4465              return false;
4466          }
4467 +
4468          public final Iterator<V> iterator() {
4469 <            return new ValueIterator<K,V>(map);
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          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 +        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 +        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  
4501 <    static final class EntrySet<K,V> extends MapView<K,V>
4502 <        implements Set<Map.Entry<K,V>> {
4503 <        EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
4504 <        public final boolean contains(Object o) {
4501 >    /**
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 >        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 &&
# Line 3157 | Line 4516 | public class ConcurrentHashMapV8<K, V>
4516                      (v = e.getValue()) != null &&
4517                      (v == r || v.equals(r)));
4518          }
4519 <        public final boolean remove(Object o) {
4519 >
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 <        public final Iterator<Map.Entry<K,V>> iterator() {
4528 <            return new EntryIterator<K,V>(map);
4527 >
4528 >        /**
4529 >         * @return an iterator over the entries of the backing map
4530 >         */
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 <        public final boolean add(Entry<K,V> e) {
4538 <            throw new UnsupportedOperationException();
4537 >
4538 >        public boolean add(Entry<K,V> e) {
4539 >            return map.putVal(e.getKey(), e.getValue(), false) == null;
4540          }
4541 <        public final boolean addAll(Collection<? extends Entry<K,V>> c) {
4542 <            throw new UnsupportedOperationException();
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 <        public boolean equals(Object o) {
4550 >
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 >                }
4559 >            }
4560 >            return h;
4561 >        }
4562 >
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 +        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 +        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  
4590 <    /* ---------------- Serialization Support -------------- */
4590 >    // -------------------------------------------------------
4591  
4592      /**
4593 <     * Stripped-down version of helper class used in previous version,
4594 <     * declared for the sake of serialization compatibility
4593 >     * Base class for bulk tasks. Repeats some fields and code from
4594 >     * class Traverser, because we need to subclass CountedCompleter.
4595       */
4596 <    static class Segment<K,V> implements Serializable {
4597 <        private static final long serialVersionUID = 2249069246763182397L;
4598 <        final float loadFactor;
4599 <        Segment(float lf) { this.loadFactor = lf; }
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 >            }
4617 >        }
4618 >
4619 >        /**
4620 >         * Same as Traverser version
4621 >         */
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      }
4649  
4650 <    /**
4651 <     * Saves the state of the {@code ConcurrentHashMapV8} instance to a
4652 <     * stream (i.e., serializes it).
4653 <     * @param s the stream
4654 <     * @serialData
4655 <     * the key (Object) and value (Object)
4656 <     * for each key-value mapping, followed by a null pair.
4657 <     * The key-value mappings are emitted in no particular order.
4658 <     */
4659 <    @SuppressWarnings("unchecked")
4660 <    private void writeObject(java.io.ObjectOutputStream s)
4661 <            throws java.io.IOException {
4662 <        if (segments == null) { // for serialization compatibility
4663 <            segments = (Segment<K,V>[])
4664 <                new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
4665 <            for (int i = 0; i < segments.length; ++i)
4666 <                segments[i] = new Segment<K,V>(LOAD_FACTOR);
4667 <        }
4668 <        s.defaultWriteObject();
4669 <        InternalIterator<K,V> it = new InternalIterator<K,V>(this);
4670 <        Object v;
4671 <        while ((v = it.advance()) != null) {
4672 <            s.writeObject(it.nextKey);
4673 <            s.writeObject(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. 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 >    @SuppressWarnings("serial")
4658 >    static final class ForEachKeyTask<K,V>
4659 >        extends BulkTask<K,V,Void> {
4660 >        final Action<? super K> action;
4661 >        ForEachKeyTask
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 >        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 >            }
4681 >        }
4682 >    }
4683 >
4684 >    @SuppressWarnings("serial")
4685 >    static final class ForEachValueTask<K,V>
4686 >        extends BulkTask<K,V,Void> {
4687 >        final Action<? super V> action;
4688 >        ForEachValueTask
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 >        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 >            }
4708 >        }
4709 >    }
4710 >
4711 >    @SuppressWarnings("serial")
4712 >    static final class ForEachEntryTask<K,V>
4713 >        extends BulkTask<K,V,Void> {
4714 >        final Action<? super Entry<K,V>> action;
4715 >        ForEachEntryTask
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 >        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 >            }
4735 >        }
4736 >    }
4737 >
4738 >    @SuppressWarnings("serial")
4739 >    static final class ForEachMappingTask<K,V>
4740 >        extends BulkTask<K,V,Void> {
4741 >        final BiAction<? super K, ? super V> action;
4742 >        ForEachMappingTask
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 >        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 >            }
4762 >        }
4763 >    }
4764 >
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<? super U> action;
4770 >        ForEachTransformedKeyTask
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, batch >>>= 1, baseLimit = h, f, tab,
4786 >                         transformer, action).fork();
4787 >                }
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 >                propagateCompletion();
4794 >            }
4795 >        }
4796 >    }
4797 >
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<? super U> action;
4803 >        ForEachTransformedValueTask
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, batch >>>= 1, baseLimit = h, f, tab,
4819 >                         transformer, action).fork();
4820 >                }
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 >                propagateCompletion();
4827 >            }
4828 >        }
4829 >    }
4830 >
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<? super U> action;
4836 >        ForEachTransformedEntryTask
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, batch >>>= 1, baseLimit = h, f, tab,
4852 >                         transformer, action).fork();
4853 >                }
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 >                propagateCompletion();
4860 >            }
4861 >        }
4862 >    }
4863 >
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<? super U> action;
4869 >        ForEachTransformedMappingTask
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<? 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, batch >>>= 1, baseLimit = h, f, tab,
4886 >                         transformer, action).fork();
4887 >                }
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 >                propagateCompletion();
4894 >            }
4895 >        }
4896 >    }
4897 >
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 >            (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, i, f, t);
4908 >            this.searchFunction = searchFunction; this.result = result;
4909 >        }
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 >                            quietlyCompleteRoot();
4935 >                        break;
4936 >                    }
4937 >                }
4938 >            }
4939          }
3221        s.writeObject(null);
3222        s.writeObject(null);
3223        segments = null; // throw away
4940      }
4941  
4942 <    /**
4943 <     * Reconstitutes the instance from a stream (that is, deserializes it).
4944 <     * @param s the stream
4945 <     */
4946 <    @SuppressWarnings("unchecked")
4947 <    private void readObject(java.io.ObjectInputStream s)
4948 <            throws java.io.IOException, ClassNotFoundException {
4949 <        s.defaultReadObject();
4950 <        this.segments = null; // unneeded
4951 <        // initialize transient final field
4952 <        UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
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 >            (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, i, f, t);
4952 >            this.searchFunction = searchFunction; this.result = result;
4953 >        }
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 >                            quietlyCompleteRoot();
4979 >                        break;
4980 >                    }
4981 >                }
4982 >            }
4983 >        }
4984 >    }
4985  
4986 <        // Create all nodes, then place in table once size is known
4987 <        long size = 0L;
4988 <        Node p = null;
4989 <        for (;;) {
4990 <            K k = (K) s.readObject();
4991 <            V v = (V) s.readObject();
4992 <            if (k != null && v != null) {
4993 <                int h = spread(k.hashCode());
4994 <                p = new Node(h, k, v, p);
4995 <                ++size;
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 >            (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, i, f, t);
4996 >            this.searchFunction = searchFunction; this.result = result;
4997 >        }
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 >                }
5026              }
3249            else
3250                break;
5027          }
5028 <        if (p != null) {
5029 <            boolean init = false;
5030 <            int n;
5031 <            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
5032 <                n = MAXIMUM_CAPACITY;
5033 <            else {
5034 <                int sz = (int)size;
5035 <                n = tableSizeFor(sz + (sz >>> 1) + 1);
5028 >    }
5029 >
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 >            (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, i, f, t);
5040 >            this.searchFunction = searchFunction; this.result = result;
5041 >        }
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 >                            quietlyCompleteRoot();
5067 >                        break;
5068 >                    }
5069 >                }
5070              }
5071 <            int sc = sizeCtl;
5072 <            boolean collide = false;
5073 <            if (n > sc &&
5074 <                UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
5075 <                try {
5076 <                    if (table == null) {
5077 <                        init = true;
5078 <                        Node[] tab = new Node[n];
5079 <                        int mask = n - 1;
5080 <                        while (p != null) {
5081 <                            int j = p.hash & mask;
5082 <                            Node next = p.next;
5083 <                            Node q = p.next = tabAt(tab, j);
5084 <                            setTabAt(tab, j, p);
5085 <                            if (!collide && q != null && q.hash == p.hash)
5086 <                                collide = true;
5087 <                            p = next;
5071 >        }
5072 >    }
5073 >
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 >            (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, i, f, t); this.nextRight = nextRight;
5085 >            this.reducer = reducer;
5086 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5096 >                      rights, reducer)).fork();
5097 >                }
5098 >                K r = null;
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 >                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 >                    }
5116 >                }
5117 >            }
5118 >        }
5119 >    }
5120 >
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 >            (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, i, f, t); this.nextRight = nextRight;
5132 >            this.reducer = reducer;
5133 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5143 >                      rights, reducer)).fork();
5144 >                }
5145 >                V r = null;
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 >                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 >                    }
5163 >                }
5164 >            }
5165 >        }
5166 >    }
5167 >
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 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5176 >             ReduceEntriesTask<K,V> 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 >        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, batch >>>= 1, baseLimit = h, f, tab,
5190 >                      rights, reducer)).fork();
5191 >                }
5192 >                Map.Entry<K,V> r = null;
5193 >                for (Node<K,V> p; (p = advance()) != null; )
5194 >                    r = (r == null) ? p : reducer.apply(r, p);
5195 >                result = r;
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 >                    }
5208 >                }
5209 >            }
5210 >        }
5211 >    }
5212 >
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 >            (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, i, f, t); this.nextRight = nextRight;
5226 >            this.transformer = transformer;
5227 >            this.reducer = reducer;
5228 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5240 >                      rights, transformer, reducer)).fork();
5241 >                }
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 >                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 >                    }
5261 >                }
5262 >            }
5263 >        }
5264 >    }
5265 >
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 >            (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, i, f, t); this.nextRight = nextRight;
5279 >            this.transformer = transformer;
5280 >            this.reducer = reducer;
5281 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5293 >                      rights, transformer, reducer)).fork();
5294 >                }
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 >                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 >                    }
5314 >                }
5315 >            }
5316 >        }
5317 >    }
5318 >
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 >            (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, i, f, t); this.nextRight = nextRight;
5332 >            this.transformer = transformer;
5333 >            this.reducer = reducer;
5334 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5346 >                      rights, transformer, reducer)).fork();
5347 >                }
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 >                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 >                    }
5367 >                }
5368 >            }
5369 >        }
5370 >    }
5371 >
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 >            (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, i, f, t); this.nextRight = nextRight;
5385 >            this.transformer = transformer;
5386 >            this.reducer = reducer;
5387 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5399 >                      rights, transformer, reducer)).fork();
5400 >                }
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 >                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 >                    }
5420 >                }
5421 >            }
5422 >        }
5423 >    }
5424 >
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;
5430 >        final double basis;
5431 >        double result;
5432 >        MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5433 >        MapReduceKeysToDoubleTask
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, i, f, t); this.nextRight = nextRight;
5440 >            this.transformer = transformer;
5441 >            this.basis = basis; this.reducer = reducer;
5442 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5455 >                      rights, transformer, r, reducer)).fork();
5456 >                }
5457 >                for (Node<K,V> p; (p = advance()) != null; )
5458 >                    r = reducer.apply(r, transformer.apply(p.key));
5459 >                result = r;
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 >                    }
5469 >                }
5470 >            }
5471 >        }
5472 >    }
5473 >
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;
5479 >        final double basis;
5480 >        double result;
5481 >        MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5482 >        MapReduceValuesToDoubleTask
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, i, f, t); this.nextRight = nextRight;
5489 >            this.transformer = transformer;
5490 >            this.basis = basis; this.reducer = reducer;
5491 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5504 >                      rights, transformer, r, reducer)).fork();
5505 >                }
5506 >                for (Node<K,V> p; (p = advance()) != null; )
5507 >                    r = reducer.apply(r, transformer.apply(p.val));
5508 >                result = r;
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 >                    }
5518 >                }
5519 >            }
5520 >        }
5521 >    }
5522 >
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;
5528 >        final double basis;
5529 >        double result;
5530 >        MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5531 >        MapReduceEntriesToDoubleTask
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, i, f, t); this.nextRight = nextRight;
5538 >            this.transformer = transformer;
5539 >            this.basis = basis; this.reducer = reducer;
5540 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5553 >                      rights, transformer, r, reducer)).fork();
5554 >                }
5555 >                for (Node<K,V> p; (p = advance()) != null; )
5556 >                    r = reducer.apply(r, transformer.apply(p));
5557 >                result = r;
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 >                    }
5567 >                }
5568 >            }
5569 >        }
5570 >    }
5571 >
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;
5577 >        final double basis;
5578 >        double result;
5579 >        MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5580 >        MapReduceMappingsToDoubleTask
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, i, f, t); this.nextRight = nextRight;
5587 >            this.transformer = transformer;
5588 >            this.basis = basis; this.reducer = reducer;
5589 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5602 >                      rights, transformer, r, reducer)).fork();
5603 >                }
5604 >                for (Node<K,V> p; (p = advance()) != null; )
5605 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5606 >                result = r;
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 >                    }
5616 >                }
5617 >            }
5618 >        }
5619 >    }
5620 >
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;
5626 >        final long basis;
5627 >        long result;
5628 >        MapReduceKeysToLongTask<K,V> rights, nextRight;
5629 >        MapReduceKeysToLongTask
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, i, f, t); this.nextRight = nextRight;
5636 >            this.transformer = transformer;
5637 >            this.basis = basis; this.reducer = reducer;
5638 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5651 >                      rights, transformer, r, reducer)).fork();
5652 >                }
5653 >                for (Node<K,V> p; (p = advance()) != null; )
5654 >                    r = reducer.apply(r, transformer.apply(p.key));
5655 >                result = r;
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 >                    }
5665 >                }
5666 >            }
5667 >        }
5668 >    }
5669 >
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;
5675 >        final long basis;
5676 >        long result;
5677 >        MapReduceValuesToLongTask<K,V> rights, nextRight;
5678 >        MapReduceValuesToLongTask
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, i, f, t); this.nextRight = nextRight;
5685 >            this.transformer = transformer;
5686 >            this.basis = basis; this.reducer = reducer;
5687 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5700 >                      rights, transformer, r, reducer)).fork();
5701 >                }
5702 >                for (Node<K,V> p; (p = advance()) != null; )
5703 >                    r = reducer.apply(r, transformer.apply(p.val));
5704 >                result = r;
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 >                    }
5714 >                }
5715 >            }
5716 >        }
5717 >    }
5718 >
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;
5724 >        final long basis;
5725 >        long result;
5726 >        MapReduceEntriesToLongTask<K,V> rights, nextRight;
5727 >        MapReduceEntriesToLongTask
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, i, f, t); this.nextRight = nextRight;
5734 >            this.transformer = transformer;
5735 >            this.basis = basis; this.reducer = reducer;
5736 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5749 >                      rights, transformer, r, reducer)).fork();
5750 >                }
5751 >                for (Node<K,V> p; (p = advance()) != null; )
5752 >                    r = reducer.apply(r, transformer.apply(p));
5753 >                result = r;
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 >                    }
5763 >                }
5764 >            }
5765 >        }
5766 >    }
5767 >
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;
5773 >        final long basis;
5774 >        long result;
5775 >        MapReduceMappingsToLongTask<K,V> rights, nextRight;
5776 >        MapReduceMappingsToLongTask
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, i, f, t); this.nextRight = nextRight;
5783 >            this.transformer = transformer;
5784 >            this.basis = basis; this.reducer = reducer;
5785 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5798 >                      rights, transformer, r, reducer)).fork();
5799 >                }
5800 >                for (Node<K,V> p; (p = advance()) != null; )
5801 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5802 >                result = r;
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 >                    }
5812 >                }
5813 >            }
5814 >        }
5815 >    }
5816 >
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;
5822 >        final int basis;
5823 >        int result;
5824 >        MapReduceKeysToIntTask<K,V> rights, nextRight;
5825 >        MapReduceKeysToIntTask
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, i, f, t); this.nextRight = nextRight;
5832 >            this.transformer = transformer;
5833 >            this.basis = basis; this.reducer = reducer;
5834 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5847 >                      rights, transformer, r, reducer)).fork();
5848 >                }
5849 >                for (Node<K,V> p; (p = advance()) != null; )
5850 >                    r = reducer.apply(r, transformer.apply(p.key));
5851 >                result = r;
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 >                    }
5861 >                }
5862 >            }
5863 >        }
5864 >    }
5865 >
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;
5871 >        final int basis;
5872 >        int result;
5873 >        MapReduceValuesToIntTask<K,V> rights, nextRight;
5874 >        MapReduceValuesToIntTask
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, i, f, t); this.nextRight = nextRight;
5881 >            this.transformer = transformer;
5882 >            this.basis = basis; this.reducer = reducer;
5883 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5896 >                      rights, transformer, r, reducer)).fork();
5897 >                }
5898 >                for (Node<K,V> p; (p = advance()) != null; )
5899 >                    r = reducer.apply(r, transformer.apply(p.val));
5900 >                result = r;
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 >                    }
5910 >                }
5911 >            }
5912 >        }
5913 >    }
5914 >
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;
5920 >        final int basis;
5921 >        int result;
5922 >        MapReduceEntriesToIntTask<K,V> rights, nextRight;
5923 >        MapReduceEntriesToIntTask
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, i, f, t); this.nextRight = nextRight;
5930 >            this.transformer = transformer;
5931 >            this.basis = basis; this.reducer = reducer;
5932 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5945 >                      rights, transformer, r, reducer)).fork();
5946 >                }
5947 >                for (Node<K,V> p; (p = advance()) != null; )
5948 >                    r = reducer.apply(r, transformer.apply(p));
5949 >                result = r;
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 >                    }
5959 >                }
5960 >            }
5961 >        }
5962 >    }
5963 >
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;
5969 >        final int basis;
5970 >        int result;
5971 >        MapReduceMappingsToIntTask<K,V> rights, nextRight;
5972 >        MapReduceMappingsToIntTask
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, i, f, t); this.nextRight = nextRight;
5979 >            this.transformer = transformer;
5980 >            this.basis = basis; this.reducer = reducer;
5981 >        }
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, batch >>>= 1, baseLimit = h, f, tab,
5994 >                      rights, transformer, r, reducer)).fork();
5995 >                }
5996 >                for (Node<K,V> p; (p = advance()) != null; )
5997 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5998 >                result = r;
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                          }
3279                        table = tab;
3280                        counter.add(size);
3281                        sc = n - (n >>> 2);
6102                      }
6103 <                } finally {
3284 <                    sizeCtl = sc;
6103 >                    collide = false;
6104                  }
6105 <                if (collide) { // rescan and convert to TreeBins
6106 <                    Node[] tab = table;
6107 <                    for (int i = 0; i < tab.length; ++i) {
6108 <                        int c = 0;
6109 <                        for (Node e = tabAt(tab, i); e != null; e = e.next) {
6110 <                            if (++c > TREE_THRESHOLD &&
6111 <                                (e.key instanceof Comparable)) {
6112 <                                replaceWithTreeBin(tab, i, e.key);
6113 <                                break;
6114 <                            }
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 +                    } finally {
6123 +                        cellsBusy = 0;
6124                      }
6125 +                    collide = false;
6126 +                    continue;                   // Retry with expanded table
6127                  }
6128 <            }
6129 <            if (!init) { // Can only happen if unsafely published.
6130 <                while (p != null) {
6131 <                    internalPut(p.key, p.val);
6132 <                    p = p.next;
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 +            else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
6149 +                break;                          // Fall back on using base
6150          }
6151 +        hc.code = h;                            // Record index for next time
6152      }
6153  
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 {
3317        int ss;
6166          try {
6167 <            UNSAFE = getUnsafe();
6167 >            U = getUnsafe();
6168              Class<?> k = ConcurrentHashMapV8.class;
6169 <            counterOffset = UNSAFE.objectFieldOffset
3322 <                (k.getDeclaredField("counter"));
3323 <            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          }
3331        if ((ss & (ss-1)) != 0)
3332            throw new Error("data type scale not a power of two");
3333        ASHIFT = 31 - Integer.numberOfLeadingZeros(ss);
6191      }
6192  
6193      /**
# Line 3343 | 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      }
3363
6222   }

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