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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.37 by dl, Sun Mar 4 20:34:27 2012 UTC vs.
Revision 1.119 by jsr166, Sun Dec 1 16:56:07 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.io.Serializable;
31 > import java.util.concurrent.locks.ReentrantLock;
32  
33   /**
34   * A hash table supporting full concurrency of retrievals and
# Line 36 | 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 73 | 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   *
89 * <p><em>jsr166e note: This class is a candidate replacement for
90 * java.util.concurrent.ConcurrentHashMap.<em>
91 *
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 non-null value for the given key.
234 <         *
235 <         * @param key the (non-null) key
236 <         * @return a non-null value
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);
113 <    }
114 <
115 <    /**
116 <     * A function computing a new mapping given a key and its current
117 <     * mapped value (or {@code null} if there is no current
118 <     * mapping). This is a place-holder for an upcoming JDK8
119 <     * interface.
120 <     */
121 <    public static interface RemappingFunction<K, V> {
238 >        ConcurrentHashMapSpliterator<T> trySplit();
239          /**
240 <         * Returns a new value given a key and its current value.
241 <         *
125 <         * @param key the (non-null) key
126 <         * @param value the current value, or null if there is no mapping
127 <         * @return a non-null value
240 >         * Returns an estimate of the number of elements covered by
241 >         * this Spliterator.
242           */
243 <        V remap(K key, V value);
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      /*
281       * Overview:
# Line 139 | Line 287 | public class ConcurrentHashMapV8<K, V>
287       * the same or better than java.util.HashMap, and to support high
288       * initial insertion rates on an empty table by many threads.
289       *
290 <     * Each key-value mapping is held in a Node.  Because Node fields
291 <     * can contain special values, they are defined using plain Object
292 <     * types. Similarly in turn, all internal methods that use them
293 <     * work off Object types. And similarly, so do the internal
294 <     * methods of auxiliary iterator and view classes.  All public
295 <     * generic typed methods relay in/out of these internal methods,
296 <     * supplying null-checks and casts as needed. This also allows
297 <     * many of the public methods to be factored into a smaller number
298 <     * of internal methods (although sadly not so for the five
299 <     * sprawling variants of put-related operations).
290 >     * This map usually acts as a binned (bucketed) hash table.  Each
291 >     * key-value mapping is held in a Node.  Most nodes are instances
292 >     * of the basic Node class with hash, key, value, and next
293 >     * fields. However, various subclasses exist: TreeNodes are
294 >     * arranged in balanced trees, not lists.  TreeBins hold the roots
295 >     * of sets of TreeNodes. ForwardingNodes are placed at the heads
296 >     * of bins during resizing. ReservationNodes are used as
297 >     * placeholders while establishing values in computeIfAbsent and
298 >     * related methods.  The types TreeBin, ForwardingNode, and
299 >     * ReservationNode do not hold normal user keys, values, or
300 >     * hashes, and are readily distinguishable during search etc
301 >     * because they have negative hash fields and null key and value
302 >     * fields. (These special nodes are either uncommon or transient,
303 >     * so the impact of carrying around some unused fields is
304 >     * insignificant.)
305       *
306       * The table is lazily initialized to a power-of-two size upon the
307 <     * first insertion.  Each bin in the table contains a list of
308 <     * Nodes (most often, the list has only zero or one Node).  Table
309 <     * accesses require volatile/atomic reads, writes, and CASes.
310 <     * Because there is no other way to arrange this without adding
311 <     * further indirections, we use intrinsics (sun.misc.Unsafe)
312 <     * operations.  The lists of nodes within bins are always
313 <     * accurately traversable under volatile reads, so long as lookups
314 <     * check hash code and non-nullness of value before checking key
315 <     * equality.
316 <     *
317 <     * We use the top two bits of Node hash fields for control
165 <     * purposes -- they are available anyway because of addressing
166 <     * constraints.  As explained further below, these top bits are
167 <     * used as follows:
168 <     *  00 - Normal
169 <     *  01 - Locked
170 <     *  11 - Locked and may have a thread waiting for lock
171 <     *  10 - Node is a forwarding node
172 <     *
173 <     * The lower 30 bits of each Node's hash field contain a
174 <     * transformation (for better randomization -- method "spread") of
175 <     * the key's hash code, except for forwarding nodes, for which the
176 <     * lower bits are zero (and so always have hash field == MOVED).
307 >     * first insertion.  Each bin in the table normally contains a
308 >     * list of Nodes (most often, the list has only zero or one Node).
309 >     * Table accesses require volatile/atomic reads, writes, and
310 >     * CASes.  Because there is no other way to arrange this without
311 >     * adding further indirections, we use intrinsics
312 >     * (sun.misc.Unsafe) operations.
313 >     *
314 >     * We use the top (sign) bit of Node hash fields for control
315 >     * purposes -- it is available anyway because of addressing
316 >     * constraints.  Nodes with negative hash fields are specially
317 >     * handled or ignored in map methods.
318       *
319       * Insertion (via put or its variants) of the first node in an
320       * empty bin is performed by just CASing it to the bin.  This is
321 <     * by far the most common case for put operations.  Other update
322 <     * operations (insert, delete, and replace) require locks.  We do
323 <     * not want to waste the space required to associate a distinct
324 <     * lock object with each bin, so instead use the first node of a
325 <     * bin list itself as a lock. Blocking support for these locks
326 <     * relies on the builtin "synchronized" monitors.  However, we
327 <     * also need a tryLock construction, so we overlay these by using
187 <     * bits of the Node hash field for lock control (see above), and
188 <     * so normally use builtin monitors only for blocking and
189 <     * signalling using wait/notifyAll constructions. See
190 <     * Node.tryAwaitLock.
321 >     * by far the most common case for put operations under most
322 >     * key/hash distributions.  Other update operations (insert,
323 >     * delete, and replace) require locks.  We do not want to waste
324 >     * the space required to associate a distinct lock object with
325 >     * each bin, so instead use the first node of a bin list itself as
326 >     * a lock. Locking support for these locks relies on builtin
327 >     * "synchronized" monitors.
328       *
329       * Using the first node of a list as a lock does not by itself
330       * suffice though: When a node is locked, any update must first
331       * validate that it is still the first node after locking it, and
332       * retry if not. Because new nodes are always appended to lists,
333       * once a node is first in a bin, it remains first until deleted
334 <     * or the bin becomes invalidated (upon resizing).  However,
198 <     * operations that only conditionally update may inspect nodes
199 <     * until the point of update. This is a converse of sorts to the
200 <     * lazy locking technique described by Herlihy & Shavit.
334 >     * or the bin becomes invalidated (upon resizing).
335       *
336       * The main disadvantage of per-bin locks is that other update
337       * operations on other nodes in a bin list protected by the same
338       * lock can stall, for example when user equals() or mapping
339 <     * functions take a long time.  However, statistically, this is
340 <     * not a common enough problem to outweigh the time/space overhead
341 <     * of alternatives: Under random hash codes, the frequency of
208 <     * nodes in bins follows a Poisson distribution
339 >     * functions take a long time.  However, statistically, under
340 >     * random hash codes, this is not a common problem.  Ideally, the
341 >     * frequency of nodes in bins follows a Poisson distribution
342       * (http://en.wikipedia.org/wiki/Poisson_distribution) with a
343       * parameter of about 0.5 on average, given the resizing threshold
344       * of 0.75, although with a large variance because of resizing
345       * granularity. Ignoring variance, the expected occurrences of
346       * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
347 <     * first few values are:
347 >     * first values are:
348       *
349 <     * 0:    0.607
350 <     * 1:    0.303
351 <     * 2:    0.076
352 <     * 3:    0.012
353 <     * more: 0.002
349 >     * 0:    0.60653066
350 >     * 1:    0.30326533
351 >     * 2:    0.07581633
352 >     * 3:    0.01263606
353 >     * 4:    0.00157952
354 >     * 5:    0.00015795
355 >     * 6:    0.00001316
356 >     * 7:    0.00000094
357 >     * 8:    0.00000006
358 >     * more: less than 1 in ten million
359       *
360       * Lock contention probability for two threads accessing distinct
361 <     * elements is roughly 1 / (8 * #elements).  Function "spread"
362 <     * performs hashCode randomization that improves the likelihood
363 <     * that these assumptions hold unless users define exactly the
364 <     * same value for too many hashCodes.
365 <     *
366 <     * The table is resized when occupancy exceeds an occupancy
367 <     * threshold (nominally, 0.75, but see below).  Only a single
368 <     * thread performs the resize (using field "sizeCtl", to arrange
369 <     * exclusion), but the table otherwise remains usable for reads
370 <     * and updates. Resizing proceeds by transferring bins, one by
371 <     * one, from the table to the next table.  Because we are using
372 <     * power-of-two expansion, the elements from each bin must either
373 <     * stay at same index, or move with a power of two offset. We
374 <     * eliminate unnecessary node creation by catching cases where old
375 <     * nodes can be reused because their next fields won't change.  On
376 <     * average, only about one-sixth of them need cloning when a table
377 <     * doubles. The nodes they replace will be garbage collectable as
378 <     * soon as they are no longer referenced by any reader thread that
379 <     * may be in the midst of concurrently traversing table.  Upon
380 <     * transfer, the old table bin contains only a special forwarding
381 <     * node (with hash field "MOVED") that contains the next table as
382 <     * its key. On encountering a forwarding node, access and update
383 <     * operations restart, using the new table.
384 <     *
385 <     * Each bin transfer requires its bin lock. However, unlike other
386 <     * cases, a transfer can skip a bin if it fails to acquire its
387 <     * lock, and revisit it later. Method rebuild maintains a buffer
388 <     * of TRANSFER_BUFFER_SIZE bins that have been skipped because of
389 <     * failure to acquire a lock, and blocks only if none are
390 <     * available (i.e., only very rarely).  The transfer operation
391 <     * must also ensure that all accessible bins in both the old and
392 <     * new table are usable by any traversal.  When there are no lock
393 <     * acquisition failures, this is arranged simply by proceeding
394 <     * from the last bin (table.length - 1) up towards the first.
395 <     * Upon seeing a forwarding node, traversals (see class
396 <     * InternalIterator) arrange to move to the new table without
397 <     * revisiting nodes.  However, when any node is skipped during a
398 <     * transfer, all earlier table bins may have become visible, so
399 <     * are initialized with a reverse-forwarding node back to the old
400 <     * table until the new ones are established. (This sometimes
401 <     * requires transiently locking a forwarding node, which is
402 <     * possible under the above encoding.) These more expensive
403 <     * mechanics trigger only when necessary.
361 >     * elements is roughly 1 / (8 * #elements) under random hashes.
362 >     *
363 >     * Actual hash code distributions encountered in practice
364 >     * sometimes deviate significantly from uniform randomness.  This
365 >     * includes the case when N > (1<<30), so some keys MUST collide.
366 >     * Similarly for dumb or hostile usages in which multiple keys are
367 >     * designed to have identical hash codes or ones that differs only
368 >     * in masked-out high bits. So we use a secondary strategy that
369 >     * applies when the number of nodes in a bin exceeds a
370 >     * threshold. These TreeBins use a balanced tree to hold nodes (a
371 >     * specialized form of red-black trees), bounding search time to
372 >     * O(log N).  Each search step in a TreeBin is at least twice as
373 >     * slow as in a regular list, but given that N cannot exceed
374 >     * (1<<64) (before running out of addresses) this bounds search
375 >     * steps, lock hold times, etc, to reasonable constants (roughly
376 >     * 100 nodes inspected per operation worst case) so long as keys
377 >     * are Comparable (which is very common -- String, Long, etc).
378 >     * TreeBin nodes (TreeNodes) also maintain the same "next"
379 >     * traversal pointers as regular nodes, so can be traversed in
380 >     * iterators in the same way.
381 >     *
382 >     * The table is resized when occupancy exceeds a percentage
383 >     * threshold (nominally, 0.75, but see below).  Any thread
384 >     * noticing an overfull bin may assist in resizing after the
385 >     * initiating thread allocates and sets up the replacement array.
386 >     * However, rather than stalling, these other threads may proceed
387 >     * with insertions etc.  The use of TreeBins shields us from the
388 >     * worst case effects of overfilling while resizes are in
389 >     * progress.  Resizing proceeds by transferring bins, one by one,
390 >     * from the table to the next table. However, threads claim small
391 >     * blocks of indices to transfer (via field transferIndex) before
392 >     * doing so, reducing contention.  A generation stamp in field
393 >     * sizeCtl ensures that resizings do not overlap. Because we are
394 >     * using power-of-two expansion, the elements from each bin must
395 >     * either stay at same index, or move with a power of two
396 >     * offset. We eliminate unnecessary node creation by catching
397 >     * cases where old nodes can be reused because their next fields
398 >     * won't change.  On average, only about one-sixth of them need
399 >     * cloning when a table doubles. The nodes they replace will be
400 >     * garbage collectable as soon as they are no longer referenced by
401 >     * any reader thread that may be in the midst of concurrently
402 >     * traversing table.  Upon transfer, the old table bin contains
403 >     * only a special forwarding node (with hash field "MOVED") that
404 >     * contains the next table as its key. On encountering a
405 >     * forwarding node, access and update operations restart, using
406 >     * the new table.
407 >     *
408 >     * Each bin transfer requires its bin lock, which can stall
409 >     * waiting for locks while resizing. However, because other
410 >     * threads can join in and help resize rather than contend for
411 >     * locks, average aggregate waits become shorter as resizing
412 >     * progresses.  The transfer operation must also ensure that all
413 >     * accessible bins in both the old and new table are usable by any
414 >     * traversal.  This is arranged in part by proceeding from the
415 >     * last bin (table.length - 1) up towards the first.  Upon seeing
416 >     * a forwarding node, traversals (see class Traverser) arrange to
417 >     * move to the new table without revisiting nodes.  To ensure that
418 >     * no intervening nodes are skipped even when moved out of order,
419 >     * a stack (see class TableStack) is created on first encounter of
420 >     * a forwarding node during a traversal, to maintain its place if
421 >     * later processing the current table. The need for these
422 >     * save/restore mechanics is relatively rare, but when one
423 >     * forwarding node is encountered, typically many more will be.
424 >     * So Traversers use a simple caching scheme to avoid creating so
425 >     * many new TableStack nodes. (Thanks to Peter Levart for
426 >     * suggesting use of a stack here.)
427       *
428       * The traversal scheme also applies to partial traversals of
429 <     * ranges of bins (via an alternate InternalIterator constructor)
430 <     * to support partitioned aggregate operations (that are not
431 <     * otherwise implemented yet).  Also, read-only operations give up
432 <     * if ever forwarded to a null table, which provides support for
433 <     * shutdown-style clearing, which is also not currently
273 <     * implemented.
429 >     * ranges of bins (via an alternate Traverser constructor)
430 >     * to support partitioned aggregate operations.  Also, read-only
431 >     * operations give up if ever forwarded to a null table, which
432 >     * provides support for shutdown-style clearing, which is also not
433 >     * currently implemented.
434       *
435       * Lazy table initialization minimizes footprint until first use,
436       * and also avoids resizings when the first operation is from a
# Line 278 | Line 438 | public class ConcurrentHashMapV8<K, V>
438       * These cases attempt to override the initial capacity settings,
439       * but harmlessly fail to take effect in cases of races.
440       *
441 <     * The element count is maintained using a LongAdder, which avoids
442 <     * contention on updates but can encounter cache thrashing if read
443 <     * too frequently during concurrent access. To avoid reading so
444 <     * often, resizing is attempted either when a bin lock is
445 <     * contended, or upon adding to a bin already holding two or more
446 <     * nodes (checked before adding in the xIfAbsent methods, after
447 <     * adding in others). Under uniform hash distributions, the
448 <     * probability of this occurring at threshold is around 13%,
449 <     * meaning that only about 1 in 8 puts check threshold (and after
450 <     * resizing, many fewer do so). But this approximation has high
451 <     * variance for small table sizes, so we check on any collision
452 <     * for sizes <= 64. The bulk putAll operation further reduces
453 <     * contention by only committing count updates upon these size
454 <     * checks.
441 >     * The element count is maintained using a specialization of
442 >     * LongAdder. We need to incorporate a specialization rather than
443 >     * just use a LongAdder in order to access implicit
444 >     * contention-sensing that leads to creation of multiple
445 >     * CounterCells.  The counter mechanics avoid contention on
446 >     * updates but can encounter cache thrashing if read too
447 >     * frequently during concurrent access. To avoid reading so often,
448 >     * resizing under contention is attempted only upon adding to a
449 >     * bin already holding two or more nodes. Under uniform hash
450 >     * distributions, the probability of this occurring at threshold
451 >     * is around 13%, meaning that only about 1 in 8 puts check
452 >     * threshold (and after resizing, many fewer do so).
453 >     *
454 >     * TreeBins use a special form of comparison for search and
455 >     * related operations (which is the main reason we cannot use
456 >     * existing collections such as TreeMaps). TreeBins contain
457 >     * Comparable elements, but may contain others, as well as
458 >     * elements that are Comparable but not necessarily Comparable for
459 >     * the same T, so we cannot invoke compareTo among them. To handle
460 >     * this, the tree is ordered primarily by hash value, then by
461 >     * Comparable.compareTo order if applicable.  On lookup at a node,
462 >     * if elements are not comparable or compare as 0 then both left
463 >     * and right children may need to be searched in the case of tied
464 >     * hash values. (This corresponds to the full list search that
465 >     * would be necessary if all elements were non-Comparable and had
466 >     * tied hashes.) On insertion, to keep a total ordering (or as
467 >     * close as is required here) across rebalancings, we compare
468 >     * classes and identityHashCodes as tie-breakers. The red-black
469 >     * balancing code is updated from pre-jdk-collections
470 >     * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
471 >     * based in turn on Cormen, Leiserson, and Rivest "Introduction to
472 >     * Algorithms" (CLR).
473 >     *
474 >     * TreeBins also require an additional locking mechanism.  While
475 >     * list traversal is always possible by readers even during
476 >     * updates, tree traversal is not, mainly because of tree-rotations
477 >     * that may change the root node and/or its linkages.  TreeBins
478 >     * include a simple read-write lock mechanism parasitic on the
479 >     * main bin-synchronization strategy: Structural adjustments
480 >     * associated with an insertion or removal are already bin-locked
481 >     * (and so cannot conflict with other writers) but must wait for
482 >     * ongoing readers to finish. Since there can be only one such
483 >     * waiter, we use a simple scheme using a single "waiter" field to
484 >     * block writers.  However, readers need never block.  If the root
485 >     * lock is held, they proceed along the slow traversal path (via
486 >     * next-pointers) until the lock becomes available or the list is
487 >     * exhausted, whichever comes first. These cases are not fast, but
488 >     * maximize aggregate expected throughput.
489       *
490       * Maintaining API and serialization compatibility with previous
491       * versions of this class introduces several oddities. Mainly: We
# Line 301 | Line 495 | public class ConcurrentHashMapV8<K, V>
495       * time that we can guarantee to honor it.) We also declare an
496       * unused "Segment" class that is instantiated in minimal form
497       * only when serializing.
498 +     *
499 +     * Also, solely for compatibility with previous versions of this
500 +     * class, it extends AbstractMap, even though all of its methods
501 +     * are overridden, so it is just useless baggage.
502 +     *
503 +     * This file is organized to make things a little easier to follow
504 +     * while reading than they might otherwise: First the main static
505 +     * declarations and utilities, then fields, then main public
506 +     * methods (with a few factorings of multiple public methods into
507 +     * internal ones), then sizing methods, trees, traversers, and
508 +     * bulk operations.
509       */
510  
511      /* ---------------- Constants -------------- */
# Line 342 | Line 547 | public class ConcurrentHashMapV8<K, V>
547      private static final float LOAD_FACTOR = 0.75f;
548  
549      /**
550 <     * The buffer size for skipped bins during transfers. The
551 <     * value is arbitrary but should be large enough to avoid
552 <     * most locking stalls during resizes.
550 >     * The bin count threshold for using a tree rather than list for a
551 >     * bin.  Bins are converted to trees when adding an element to a
552 >     * bin with at least this many nodes. The value must be greater
553 >     * than 2, and should be at least 8 to mesh with assumptions in
554 >     * tree removal about conversion back to plain bins upon
555 >     * shrinkage.
556       */
557 <    private static final int TRANSFER_BUFFER_SIZE = 32;
557 >    static final int TREEIFY_THRESHOLD = 8;
558  
559 <    /*
560 <     * Encodings for special uses of Node hash fields. See above for
561 <     * explanation.
559 >    /**
560 >     * The bin count threshold for untreeifying a (split) bin during a
561 >     * resize operation. Should be less than TREEIFY_THRESHOLD, and at
562 >     * most 6 to mesh with shrinkage detection under removal.
563       */
564 <    static final int MOVED     = 0x80000000; // hash field for forwarding nodes
356 <    static final int LOCKED    = 0x40000000; // set/tested only as a bit
357 <    static final int WAITING   = 0xc0000000; // both bits set/tested together
358 <    static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
564 >    static final int UNTREEIFY_THRESHOLD = 6;
565  
566 <    /* ---------------- Fields -------------- */
566 >    /**
567 >     * The smallest table capacity for which bins may be treeified.
568 >     * (Otherwise the table is resized if too many nodes in a bin.)
569 >     * The value should be at least 4 * TREEIFY_THRESHOLD to avoid
570 >     * conflicts between resizing and treeification thresholds.
571 >     */
572 >    static final int MIN_TREEIFY_CAPACITY = 64;
573  
574      /**
575 <     * The array of bins. Lazily initialized upon first insertion.
576 <     * Size is always a power of two. Accessed directly by iterators.
575 >     * Minimum number of rebinnings per transfer step. Ranges are
576 >     * subdivided to allow multiple resizer threads.  This value
577 >     * serves as a lower bound to avoid resizers encountering
578 >     * excessive memory contention.  The value should be at least
579 >     * DEFAULT_CAPACITY.
580       */
581 <    transient volatile Node[] table;
581 >    private static final int MIN_TRANSFER_STRIDE = 16;
582  
583      /**
584 <     * The counter maintaining number of elements.
584 >     * The number of bits used for generation stamp in sizeCtl.
585 >     * Must be at least 6 for 32bit arrays.
586       */
587 <    private transient final LongAdder counter;
587 >    private static int RESIZE_STAMP_BITS = 16;
588  
589      /**
590 <     * Table initialization and resizing control.  When negative, the
591 <     * table is being initialized or resized. Otherwise, when table is
376 <     * null, holds the initial table size to use upon creation, or 0
377 <     * for default. After initialization, holds the next element count
378 <     * value upon which to resize the table.
590 >     * The maximum number of threads that can help resize.
591 >     * Must fit in 32 - RESIZE_STAMP_BITS bits.
592       */
593 <    private transient volatile int sizeCtl;
593 >    private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
594  
595 <    // views
596 <    private transient KeySet<K,V> keySet;
597 <    private transient Values<K,V> values;
598 <    private transient EntrySet<K,V> entrySet;
595 >    /**
596 >     * The bit shift for recording size stamp in sizeCtl.
597 >     */
598 >    private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
599  
600 <    /** For serialization compatibility. Null unless serialized; see below */
601 <    private Segment<K,V>[] segments;
600 >    /*
601 >     * Encodings for Node hash fields. See above for explanation.
602 >     */
603 >    static final int MOVED     = -1; // hash for forwarding nodes
604 >    static final int TREEBIN   = -2; // hash for roots of trees
605 >    static final int RESERVED  = -3; // hash for transient reservations
606 >    static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
607 >
608 >    /** Number of CPUS, to place bounds on some sizings */
609 >    static final int NCPU = Runtime.getRuntime().availableProcessors();
610 >
611 >    /** For serialization compatibility. */
612 >    private static final ObjectStreamField[] serialPersistentFields = {
613 >        new ObjectStreamField("segments", Segment[].class),
614 >        new ObjectStreamField("segmentMask", Integer.TYPE),
615 >        new ObjectStreamField("segmentShift", Integer.TYPE)
616 >    };
617  
618      /* ---------------- Nodes -------------- */
619  
620      /**
621 <     * Key-value entry. Note that this is never exported out as a
622 <     * user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry
623 <     * below). Nodes with a hash field of MOVED are special, and do
624 <     * not contain user keys or values.  Otherwise, keys are never
625 <     * null, and null val fields indicate that a node is in the
626 <     * process of being deleted or created. For purposes of read-only
627 <     * access, a key may be read before a val, but can only be used
628 <     * after checking val to be non-null.
629 <     */
630 <    static final class Node {
631 <        volatile int hash;
632 <        final Object key;
405 <        volatile Object val;
406 <        volatile Node next;
621 >     * Key-value entry.  This class is never exported out as a
622 >     * user-mutable Map.Entry (i.e., one supporting setValue; see
623 >     * MapEntry below), but can be used for read-only traversals used
624 >     * in bulk tasks.  Subclasses of Node with a negative hash field
625 >     * are special, and contain null keys and values (but are never
626 >     * exported).  Otherwise, keys and vals are never null.
627 >     */
628 >    static class Node<K,V> implements Map.Entry<K,V> {
629 >        final int hash;
630 >        final K key;
631 >        volatile V val;
632 >        volatile Node<K,V> next;
633  
634 <        Node(int hash, Object key, Object val, Node next) {
634 >        Node(int hash, K key, V val, Node<K,V> next) {
635              this.hash = hash;
636              this.key = key;
637              this.val = val;
638              this.next = next;
639          }
640  
641 <        /** CompareAndSet the hash field */
642 <        final boolean casHash(int cmp, int val) {
643 <            return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
641 >        public final K getKey()       { return key; }
642 >        public final V getValue()     { return val; }
643 >        public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
644 >        public final String toString(){ return key + "=" + val; }
645 >        public final V setValue(V value) {
646 >            throw new UnsupportedOperationException();
647          }
648  
649 <        /** The number of spins before blocking for a lock */
650 <        static final int MAX_SPINS =
651 <            Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
652 <
653 <        /**
654 <         * Spins a while if LOCKED bit set and this node is the first
655 <         * of its bin, and then sets WAITING bits on hash field and
427 <         * blocks (once) if they are still set.  It is OK for this
428 <         * method to return even if lock is not available upon exit,
429 <         * which enables these simple single-wait mechanics.
430 <         *
431 <         * The corresponding signalling operation is performed within
432 <         * callers: Upon detecting that WAITING has been set when
433 <         * unlocking lock (via a failed CAS from non-waiting LOCKED
434 <         * state), unlockers acquire the sync lock and perform a
435 <         * notifyAll.
436 <         */
437 <        final void tryAwaitLock(Node[] tab, int i) {
438 <            if (tab != null && i >= 0 && i < tab.length) { // bounds check
439 <                int r = ThreadLocalRandom.current().nextInt(); // randomize spins
440 <                int spins = MAX_SPINS, h;
441 <                while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
442 <                    if (spins >= 0) {
443 <                        r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
444 <                        if (r >= 0 && --spins == 0)
445 <                            Thread.yield();  // yield before block
446 <                    }
447 <                    else if (casHash(h, h | WAITING)) {
448 <                        synchronized (this) {
449 <                            if (tabAt(tab, i) == this &&
450 <                                (hash & WAITING) == WAITING) {
451 <                                try {
452 <                                    wait();
453 <                                } catch (InterruptedException ie) {
454 <                                    Thread.currentThread().interrupt();
455 <                                }
456 <                            }
457 <                            else
458 <                                notifyAll(); // possibly won race vs signaller
459 <                        }
460 <                        break;
461 <                    }
462 <                }
463 <            }
649 >        public final boolean equals(Object o) {
650 >            Object k, v, u; Map.Entry<?,?> e;
651 >            return ((o instanceof Map.Entry) &&
652 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
653 >                    (v = e.getValue()) != null &&
654 >                    (k == key || k.equals(key)) &&
655 >                    (v == (u = val) || v.equals(u)));
656          }
657  
658 <        // Unsafe mechanics for casHash
659 <        private static final sun.misc.Unsafe UNSAFE;
660 <        private static final long hashOffset;
661 <
662 <        static {
663 <            try {
664 <                UNSAFE = getUnsafe();
665 <                Class<?> k = Node.class;
666 <                hashOffset = UNSAFE.objectFieldOffset
667 <                    (k.getDeclaredField("hash"));
668 <            } catch (Exception e) {
669 <                throw new Error(e);
670 <            }
658 >        /**
659 >         * Virtualized support for map.get(); overridden in subclasses.
660 >         */
661 >        Node<K,V> find(int h, Object k) {
662 >            Node<K,V> e = this;
663 >            if (k != null) {
664 >                do {
665 >                    K ek;
666 >                    if (e.hash == h &&
667 >                        ((ek = e.key) == k || (ek != null && k.equals(ek))))
668 >                        return e;
669 >                } while ((e = e.next) != null);
670 >            }
671 >            return null;
672          }
673      }
674  
675 <    /* ---------------- Table element access -------------- */
676 <
677 <    /*
678 <     * Volatile access methods are used for table elements as well as
679 <     * elements of in-progress next table while resizing.  Uses are
680 <     * null checked by callers, and implicitly bounds-checked, relying
681 <     * on the invariants that tab arrays have non-zero size, and all
682 <     * indices are masked with (tab.length - 1) which is never
683 <     * negative and always less than length. Note that, to be correct
684 <     * wrt arbitrary concurrency errors by users, bounds checks must
685 <     * operate on local variables, which accounts for some odd-looking
686 <     * inline assignments below.
675 >    /* ---------------- Static utilities -------------- */
676 >
677 >    /**
678 >     * Spreads (XORs) higher bits of hash to lower and also forces top
679 >     * bit to 0. Because the table uses power-of-two masking, sets of
680 >     * hashes that vary only in bits above the current mask will
681 >     * always collide. (Among known examples are sets of Float keys
682 >     * holding consecutive whole numbers in small tables.)  So we
683 >     * apply a transform that spreads the impact of higher bits
684 >     * downward. There is a tradeoff between speed, utility, and
685 >     * quality of bit-spreading. Because many common sets of hashes
686 >     * are already reasonably distributed (so don't benefit from
687 >     * spreading), and because we use trees to handle large sets of
688 >     * collisions in bins, we just XOR some shifted bits in the
689 >     * cheapest possible way to reduce systematic lossage, as well as
690 >     * to incorporate impact of the highest bits that would otherwise
691 >     * never be used in index calculations because of table bounds.
692       */
693 <
694 <    static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
497 <        return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
498 <    }
499 <
500 <    private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
501 <        return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
502 <    }
503 <
504 <    private static final void setTabAt(Node[] tab, int i, Node v) {
505 <        UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
693 >    static final int spread(int h) {
694 >        return (h ^ (h >>> 16)) & HASH_BITS;
695      }
696  
508    /* ---------------- Internal access and update methods -------------- */
509
697      /**
698 <     * Applies a supplemental hash function to a given hashCode, which
699 <     * defends against poor quality hash functions.  The result must
513 <     * be have the top 2 bits clear. For reasonable performance, this
514 <     * function must have good avalanche properties; i.e., that each
515 <     * bit of the argument affects each bit of the result. (Although
516 <     * we don't care about the unused top 2 bits.)
698 >     * Returns a power of two table size for the given desired capacity.
699 >     * See Hackers Delight, sec 3.2
700       */
701 <    private static final int spread(int h) {
702 <        // Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
703 <        // Despite two multiplies, this is often faster than others
704 <        // with comparable bit-spread properties.
705 <        h ^= h >>> 16;
706 <        h *= 0x85ebca6b;
707 <        h ^= h >>> 13;
708 <        h *= 0xc2b2ae35;
526 <        return ((h >>> 16) ^ h) & HASH_BITS; // mask out top bits
701 >    private static final int tableSizeFor(int c) {
702 >        int n = c - 1;
703 >        n |= n >>> 1;
704 >        n |= n >>> 2;
705 >        n |= n >>> 4;
706 >        n |= n >>> 8;
707 >        n |= n >>> 16;
708 >        return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
709      }
710  
711 <    /** Implementation for get and containsKey */
712 <    private final Object internalGet(Object k) {
713 <        int h = spread(k.hashCode());
714 <        retry: for (Node[] tab = table; tab != null;) {
715 <            Node e; Object ek, ev; int eh;    // locals to read fields once
716 <            for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
717 <                if ((eh = e.hash) == MOVED) {
718 <                    tab = (Node[])e.key;      // restart with new table
719 <                    continue retry;
711 >    /**
712 >     * Returns x's Class if it is of the form "class C implements
713 >     * Comparable<C>", else null.
714 >     */
715 >    static Class<?> comparableClassFor(Object x) {
716 >        if (x instanceof Comparable) {
717 >            Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
718 >            if ((c = x.getClass()) == String.class) // bypass checks
719 >                return c;
720 >            if ((ts = c.getGenericInterfaces()) != null) {
721 >                for (int i = 0; i < ts.length; ++i) {
722 >                    if (((t = ts[i]) instanceof ParameterizedType) &&
723 >                        ((p = (ParameterizedType)t).getRawType() ==
724 >                         Comparable.class) &&
725 >                        (as = p.getActualTypeArguments()) != null &&
726 >                        as.length == 1 && as[0] == c) // type arg is c
727 >                        return c;
728                  }
539                if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
540                    ((ek = e.key) == k || k.equals(ek)))
541                    return ev;
729              }
543            break;
730          }
731          return null;
732      }
733  
734      /**
735 <     * Implementation for the four public remove/replace methods:
736 <     * Replaces node value with v, conditional upon match of cv if
551 <     * non-null.  If resulting value is null, delete.
735 >     * Returns k.compareTo(x) if x matches kc (k's screened comparable
736 >     * class), else 0.
737       */
738 <    private final Object internalReplace(Object k, Object v, Object cv) {
739 <        int h = spread(k.hashCode());
740 <        Object oldVal = null;
741 <        for (Node[] tab = table;;) {
557 <            Node f; int i, fh;
558 <            if (tab == null ||
559 <                (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
560 <                break;
561 <            else if ((fh = f.hash) == MOVED)
562 <                tab = (Node[])f.key;
563 <            else if ((fh & HASH_BITS) != h && f.next == null) // precheck
564 <                break;                          // rules out possible existence
565 <            else if ((fh & LOCKED) != 0) {
566 <                checkForResize();               // try resizing if can't get lock
567 <                f.tryAwaitLock(tab, i);
568 <            }
569 <            else if (f.casHash(fh, fh | LOCKED)) {
570 <                boolean validated = false;
571 <                boolean deleted = false;
572 <                try {
573 <                    if (tabAt(tab, i) == f) {
574 <                        validated = true;
575 <                        for (Node e = f, pred = null;;) {
576 <                            Object ek, ev;
577 <                            if ((e.hash & HASH_BITS) == h &&
578 <                                ((ev = e.val) != null) &&
579 <                                ((ek = e.key) == k || k.equals(ek))) {
580 <                                if (cv == null || cv == ev || cv.equals(ev)) {
581 <                                    oldVal = ev;
582 <                                    if ((e.val = v) == null) {
583 <                                        deleted = true;
584 <                                        Node en = e.next;
585 <                                        if (pred != null)
586 <                                            pred.next = en;
587 <                                        else
588 <                                            setTabAt(tab, i, en);
589 <                                    }
590 <                                }
591 <                                break;
592 <                            }
593 <                            pred = e;
594 <                            if ((e = e.next) == null)
595 <                                break;
596 <                        }
597 <                    }
598 <                } finally {
599 <                    if (!f.casHash(fh | LOCKED, fh)) {
600 <                        f.hash = fh;
601 <                        synchronized (f) { f.notifyAll(); };
602 <                    }
603 <                }
604 <                if (validated) {
605 <                    if (deleted)
606 <                        counter.add(-1L);
607 <                    break;
608 <                }
609 <            }
610 <        }
611 <        return oldVal;
738 >    @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
739 >    static int compareComparables(Class<?> kc, Object k, Object x) {
740 >        return (x == null || x.getClass() != kc ? 0 :
741 >                ((Comparable)k).compareTo(x));
742      }
743  
744 +    /* ---------------- Table element access -------------- */
745 +
746      /*
747 <     * Internal versions of the five insertion methods, each a
748 <     * little more complicated than the last. All have
749 <     * the same basic structure as the first (internalPut):
750 <     *  1. If table uninitialized, create
751 <     *  2. If bin empty, try to CAS new node
752 <     *  3. If bin stale, use new table
753 <     *  4. Lock and validate; if valid, scan and add or update
754 <     *
755 <     * The others interweave other checks and/or alternative actions:
756 <     *  * Plain put checks for and performs resize after insertion.
757 <     *  * putIfAbsent prescans for mapping without lock (and fails to add
758 <     *    if present), which also makes pre-emptive resize checks worthwhile.
759 <     *  * computeIfAbsent extends form used in putIfAbsent with additional
760 <     *    mechanics to deal with, calls, potential exceptions and null
629 <     *    returns from function call.
630 <     *  * compute uses the same function-call mechanics, but without
631 <     *    the prescans
632 <     *  * putAll attempts to pre-allocate enough table space
633 <     *    and more lazily performs count updates and checks.
634 <     *
635 <     * Someday when details settle down a bit more, it might be worth
636 <     * some factoring to reduce sprawl.
637 <     */
638 <
639 <    /** Implementation for put */
640 <    private final Object internalPut(Object k, Object v) {
641 <        int h = spread(k.hashCode());
642 <        boolean checkSize = false;
643 <        for (Node[] tab = table;;) {
644 <            int i; Node f; int fh;
645 <            if (tab == null)
646 <                tab = initTable();
647 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
648 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
649 <                    break;                   // no lock when adding to empty bin
650 <            }
651 <            else if ((fh = f.hash) == MOVED)
652 <                tab = (Node[])f.key;
653 <            else if ((fh & LOCKED) != 0) {
654 <                checkForResize();
655 <                f.tryAwaitLock(tab, i);
656 <            }
657 <            else if (f.casHash(fh, fh | LOCKED)) {
658 <                Object oldVal = null;
659 <                boolean validated = false;
660 <                try {                        // needed in case equals() throws
661 <                    if (tabAt(tab, i) == f) {
662 <                        validated = true;    // retry if 1st already deleted
663 <                        for (Node e = f;;) {
664 <                            Object ek, ev;
665 <                            if ((e.hash & HASH_BITS) == h &&
666 <                                (ev = e.val) != null &&
667 <                                ((ek = e.key) == k || k.equals(ek))) {
668 <                                oldVal = ev;
669 <                                e.val = v;
670 <                                break;
671 <                            }
672 <                            Node last = e;
673 <                            if ((e = e.next) == null) {
674 <                                last.next = new Node(h, k, v, null);
675 <                                if (last != f || tab.length <= 64)
676 <                                    checkSize = true;
677 <                                break;
678 <                            }
679 <                        }
680 <                    }
681 <                } finally {                  // unlock and signal if needed
682 <                    if (!f.casHash(fh | LOCKED, fh)) {
683 <                        f.hash = fh;
684 <                        synchronized (f) { f.notifyAll(); };
685 <                    }
686 <                }
687 <                if (validated) {
688 <                    if (oldVal != null)
689 <                        return oldVal;
690 <                    break;
691 <                }
692 <            }
693 <        }
694 <        counter.add(1L);
695 <        if (checkSize)
696 <            checkForResize();
697 <        return null;
698 <    }
747 >     * Volatile access methods are used for table elements as well as
748 >     * elements of in-progress next table while resizing.  All uses of
749 >     * the tab arguments must be null checked by callers.  All callers
750 >     * also paranoically precheck that tab's length is not zero (or an
751 >     * equivalent check), thus ensuring that any index argument taking
752 >     * the form of a hash value anded with (length - 1) is a valid
753 >     * index.  Note that, to be correct wrt arbitrary concurrency
754 >     * errors by users, these checks must operate on local variables,
755 >     * which accounts for some odd-looking inline assignments below.
756 >     * Note that calls to setTabAt always occur within locked regions,
757 >     * and so in principle require only release ordering, not
758 >     * full volatile semantics, but are currently coded as volatile
759 >     * writes to be conservative.
760 >     */
761  
762 <    /** Implementation for putIfAbsent */
763 <    private final Object internalPutIfAbsent(Object k, Object v) {
764 <        int h = spread(k.hashCode());
703 <        for (Node[] tab = table;;) {
704 <            int i; Node f; int fh; Object fk, fv;
705 <            if (tab == null)
706 <                tab = initTable();
707 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
708 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
709 <                    break;
710 <            }
711 <            else if ((fh = f.hash) == MOVED)
712 <                tab = (Node[])f.key;
713 <            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
714 <                     ((fk = f.key) == k || k.equals(fk)))
715 <                return fv;
716 <            else {
717 <                Node g = f.next;
718 <                if (g != null) { // at least 2 nodes -- search and maybe resize
719 <                    for (Node e = g;;) {
720 <                        Object ek, ev;
721 <                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
722 <                            ((ek = e.key) == k || k.equals(ek)))
723 <                            return ev;
724 <                        if ((e = e.next) == null) {
725 <                            checkForResize();
726 <                            break;
727 <                        }
728 <                    }
729 <                }
730 <                if (((fh = f.hash) & LOCKED) != 0) {
731 <                    checkForResize();
732 <                    f.tryAwaitLock(tab, i);
733 <                }
734 <                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
735 <                    Object oldVal = null;
736 <                    boolean validated = false;
737 <                    try {
738 <                        if (tabAt(tab, i) == f) {
739 <                            validated = true;
740 <                            for (Node e = f;;) {
741 <                                Object ek, ev;
742 <                                if ((e.hash & HASH_BITS) == h &&
743 <                                    (ev = e.val) != null &&
744 <                                    ((ek = e.key) == k || k.equals(ek))) {
745 <                                    oldVal = ev;
746 <                                    break;
747 <                                }
748 <                                Node last = e;
749 <                                if ((e = e.next) == null) {
750 <                                    last.next = new Node(h, k, v, null);
751 <                                    break;
752 <                                }
753 <                            }
754 <                        }
755 <                    } finally {
756 <                        if (!f.casHash(fh | LOCKED, fh)) {
757 <                            f.hash = fh;
758 <                            synchronized (f) { f.notifyAll(); };
759 <                        }
760 <                    }
761 <                    if (validated) {
762 <                        if (oldVal != null)
763 <                            return oldVal;
764 <                        break;
765 <                    }
766 <                }
767 <            }
768 <        }
769 <        counter.add(1L);
770 <        return null;
762 >    @SuppressWarnings("unchecked")
763 >    static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
764 >        return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
765      }
766  
767 <    /** Implementation for computeIfAbsent */
768 <    private final Object internalComputeIfAbsent(K k,
769 <                                                 MappingFunction<? super K, ?> mf) {
776 <        int h = spread(k.hashCode());
777 <        Object val = null;
778 <        for (Node[] tab = table;;) {
779 <            Node f; int i, fh; Object fk, fv;
780 <            if (tab == null)
781 <                tab = initTable();
782 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
783 <                Node node = new Node(fh = h | LOCKED, k, null, null);
784 <                boolean validated = false;
785 <                if (casTabAt(tab, i, null, node)) {
786 <                    validated = true;
787 <                    try {
788 <                        if ((val = mf.map(k)) != null)
789 <                            node.val = val;
790 <                    } finally {
791 <                        if (val == null)
792 <                            setTabAt(tab, i, null);
793 <                        if (!node.casHash(fh, h)) {
794 <                            node.hash = h;
795 <                            synchronized (node) { node.notifyAll(); };
796 <                        }
797 <                    }
798 <                }
799 <                if (validated)
800 <                    break;
801 <            }
802 <            else if ((fh = f.hash) == MOVED)
803 <                tab = (Node[])f.key;
804 <            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
805 <                     ((fk = f.key) == k || k.equals(fk)))
806 <                return fv;
807 <            else {
808 <                Node g = f.next;
809 <                if (g != null) {
810 <                    for (Node e = g;;) {
811 <                        Object ek, ev;
812 <                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
813 <                            ((ek = e.key) == k || k.equals(ek)))
814 <                            return ev;
815 <                        if ((e = e.next) == null) {
816 <                            checkForResize();
817 <                            break;
818 <                        }
819 <                    }
820 <                }
821 <                if (((fh = f.hash) & LOCKED) != 0) {
822 <                    checkForResize();
823 <                    f.tryAwaitLock(tab, i);
824 <                }
825 <                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
826 <                    boolean validated = false;
827 <                    try {
828 <                        if (tabAt(tab, i) == f) {
829 <                            validated = true;
830 <                            for (Node e = f;;) {
831 <                                Object ek, ev;
832 <                                if ((e.hash & HASH_BITS) == h &&
833 <                                    (ev = e.val) != null &&
834 <                                    ((ek = e.key) == k || k.equals(ek))) {
835 <                                    val = ev;
836 <                                    break;
837 <                                }
838 <                                Node last = e;
839 <                                if ((e = e.next) == null) {
840 <                                    if ((val = mf.map(k)) != null)
841 <                                        last.next = new Node(h, k, val, null);
842 <                                    break;
843 <                                }
844 <                            }
845 <                        }
846 <                    } finally {
847 <                        if (!f.casHash(fh | LOCKED, fh)) {
848 <                            f.hash = fh;
849 <                            synchronized (f) { f.notifyAll(); };
850 <                        }
851 <                    }
852 <                    if (validated)
853 <                        break;
854 <                }
855 <            }
856 <        }
857 <        if (val == null)
858 <            throw new NullPointerException();
859 <        counter.add(1L);
860 <        return val;
767 >    static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
768 >                                        Node<K,V> c, Node<K,V> v) {
769 >        return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
770      }
771  
772 <    /** Implementation for compute */
773 <    @SuppressWarnings("unchecked")
865 <    private final Object internalCompute(K k,
866 <                                         RemappingFunction<? super K, V> mf) {
867 <        int h = spread(k.hashCode());
868 <        Object val = null;
869 <        boolean added = false;
870 <        boolean checkSize = false;
871 <        for (Node[] tab = table;;) {
872 <            Node f; int i, fh;
873 <            if (tab == null)
874 <                tab = initTable();
875 <            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
876 <                Node node = new Node(fh = h | LOCKED, k, null, null);
877 <                boolean validated = false;
878 <                if (casTabAt(tab, i, null, node)) {
879 <                    validated = true;
880 <                    try {
881 <                        if ((val = mf.remap(k, null)) != null) {
882 <                            node.val = val;
883 <                            added = true;
884 <                        }
885 <                    } finally {
886 <                        if (!added)
887 <                            setTabAt(tab, i, null);
888 <                        if (!node.casHash(fh, h)) {
889 <                            node.hash = h;
890 <                            synchronized (node) { node.notifyAll(); };
891 <                        }
892 <                    }
893 <                }
894 <                if (validated)
895 <                    break;
896 <            }
897 <            else if ((fh = f.hash) == MOVED)
898 <                tab = (Node[])f.key;
899 <            else if ((fh & LOCKED) != 0) {
900 <                checkForResize();
901 <                f.tryAwaitLock(tab, i);
902 <            }
903 <            else if (f.casHash(fh, fh | LOCKED)) {
904 <                boolean validated = false;
905 <                try {
906 <                    if (tabAt(tab, i) == f) {
907 <                        validated = true;
908 <                        for (Node e = f;;) {
909 <                            Object ek, ev;
910 <                            if ((e.hash & HASH_BITS) == h &&
911 <                                (ev = e.val) != null &&
912 <                                ((ek = e.key) == k || k.equals(ek))) {
913 <                                val = mf.remap(k, (V)ev);
914 <                                if (val != null)
915 <                                    e.val = val;
916 <                                break;
917 <                            }
918 <                            Node last = e;
919 <                            if ((e = e.next) == null) {
920 <                                if ((val = mf.remap(k, null)) != null) {
921 <                                    last.next = new Node(h, k, val, null);
922 <                                    added = true;
923 <                                    if (last != f || tab.length <= 64)
924 <                                        checkSize = true;
925 <                                }
926 <                                break;
927 <                            }
928 <                        }
929 <                    }
930 <                } finally {
931 <                    if (!f.casHash(fh | LOCKED, fh)) {
932 <                        f.hash = fh;
933 <                        synchronized (f) { f.notifyAll(); };
934 <                    }
935 <                }
936 <                if (validated)
937 <                    break;
938 <            }
939 <        }
940 <        if (val == null)
941 <            throw new NullPointerException();
942 <        if (added) {
943 <            counter.add(1L);
944 <            if (checkSize)
945 <                checkForResize();
946 <        }
947 <        return val;
772 >    static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
773 >        U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
774      }
775  
776 <    /** Implementation for putAll */
951 <    private final void internalPutAll(Map<?, ?> m) {
952 <        tryPresize(m.size());
953 <        long delta = 0L;     // number of uncommitted additions
954 <        boolean npe = false; // to throw exception on exit for nulls
955 <        try {                // to clean up counts on other exceptions
956 <            for (Map.Entry<?, ?> entry : m.entrySet()) {
957 <                Object k, v;
958 <                if (entry == null || (k = entry.getKey()) == null ||
959 <                    (v = entry.getValue()) == null) {
960 <                    npe = true;
961 <                    break;
962 <                }
963 <                int h = spread(k.hashCode());
964 <                for (Node[] tab = table;;) {
965 <                    int i; Node f; int fh;
966 <                    if (tab == null)
967 <                        tab = initTable();
968 <                    else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
969 <                        if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
970 <                            ++delta;
971 <                            break;
972 <                        }
973 <                    }
974 <                    else if ((fh = f.hash) == MOVED)
975 <                        tab = (Node[])f.key;
976 <                    else if ((fh & LOCKED) != 0) {
977 <                        counter.add(delta);
978 <                        delta = 0L;
979 <                        checkForResize();
980 <                        f.tryAwaitLock(tab, i);
981 <                    }
982 <                    else if (f.casHash(fh, fh | LOCKED)) {
983 <                        boolean validated = false;
984 <                        boolean tooLong = false;
985 <                        try {
986 <                            if (tabAt(tab, i) == f) {
987 <                                validated = true;
988 <                                for (Node e = f;;) {
989 <                                    Object ek, ev;
990 <                                    if ((e.hash & HASH_BITS) == h &&
991 <                                        (ev = e.val) != null &&
992 <                                        ((ek = e.key) == k || k.equals(ek))) {
993 <                                        e.val = v;
994 <                                        break;
995 <                                    }
996 <                                    Node last = e;
997 <                                    if ((e = e.next) == null) {
998 <                                        ++delta;
999 <                                        last.next = new Node(h, k, v, null);
1000 <                                        break;
1001 <                                    }
1002 <                                    tooLong = true;
1003 <                                }
1004 <                            }
1005 <                        } finally {
1006 <                            if (!f.casHash(fh | LOCKED, fh)) {
1007 <                                f.hash = fh;
1008 <                                synchronized (f) { f.notifyAll(); };
1009 <                            }
1010 <                        }
1011 <                        if (validated) {
1012 <                            if (tooLong) {
1013 <                                counter.add(delta);
1014 <                                delta = 0L;
1015 <                                checkForResize();
1016 <                            }
1017 <                            break;
1018 <                        }
1019 <                    }
1020 <                }
1021 <            }
1022 <        } finally {
1023 <            if (delta != 0)
1024 <                counter.add(delta);
1025 <        }
1026 <        if (npe)
1027 <            throw new NullPointerException();
1028 <    }
1029 <
1030 <    /* ---------------- Table Initialization and Resizing -------------- */
776 >    /* ---------------- Fields -------------- */
777  
778      /**
779 <     * Returns a power of two table size for the given desired capacity.
780 <     * See Hackers Delight, sec 3.2
779 >     * The array of bins. Lazily initialized upon first insertion.
780 >     * Size is always a power of two. Accessed directly by iterators.
781       */
782 <    private static final int tableSizeFor(int c) {
1037 <        int n = c - 1;
1038 <        n |= n >>> 1;
1039 <        n |= n >>> 2;
1040 <        n |= n >>> 4;
1041 <        n |= n >>> 8;
1042 <        n |= n >>> 16;
1043 <        return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1044 <    }
782 >    transient volatile Node<K,V>[] table;
783  
784      /**
785 <     * Initializes table, using the size recorded in sizeCtl.
785 >     * The next table to use; non-null only while resizing.
786       */
787 <    private final Node[] initTable() {
1050 <        Node[] tab; int sc;
1051 <        while ((tab = table) == null) {
1052 <            if ((sc = sizeCtl) < 0)
1053 <                Thread.yield(); // lost initialization race; just spin
1054 <            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1055 <                try {
1056 <                    if ((tab = table) == null) {
1057 <                        int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1058 <                        tab = table = new Node[n];
1059 <                        sc = n - (n >>> 2);
1060 <                    }
1061 <                } finally {
1062 <                    sizeCtl = sc;
1063 <                }
1064 <                break;
1065 <            }
1066 <        }
1067 <        return tab;
1068 <    }
787 >    private transient volatile Node<K,V>[] nextTable;
788  
789      /**
790 <     * If table is too small and not already resizing, creates next
791 <     * table and transfers bins.  Rechecks occupancy after a transfer
792 <     * to see if another resize is already needed because resizings
793 <     * are lagging additions.
794 <     */
1076 <    private final void checkForResize() {
1077 <        Node[] tab; int n, sc;
1078 <        while ((tab = table) != null &&
1079 <               (n = tab.length) < MAXIMUM_CAPACITY &&
1080 <               (sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1081 <               UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1082 <            try {
1083 <                if (tab == table) {
1084 <                    table = rebuild(tab);
1085 <                    sc = (n << 1) - (n >>> 1);
1086 <                }
1087 <            } finally {
1088 <                sizeCtl = sc;
1089 <            }
1090 <        }
1091 <    }
790 >     * Base counter value, used mainly when there is no contention,
791 >     * but also as a fallback during table initialization
792 >     * races. Updated via CAS.
793 >     */
794 >    private transient volatile long baseCount;
795  
796      /**
797 <     * Tries to presize table to accommodate the given number of elements.
798 <     *
799 <     * @param size number of elements (doesn't need to be perfectly accurate)
797 >     * Table initialization and resizing control.  When negative, the
798 >     * table is being initialized or resized: -1 for initialization,
799 >     * else -(1 + the number of active resizing threads).  Otherwise,
800 >     * when table is null, holds the initial table size to use upon
801 >     * creation, or 0 for default. After initialization, holds the
802 >     * next element count value upon which to resize the table.
803       */
804 <    private final void tryPresize(int size) {
1099 <        int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1100 <            tableSizeFor(size + (size >>> 1) + 1);
1101 <        int sc;
1102 <        while ((sc = sizeCtl) >= 0) {
1103 <            Node[] tab = table; int n;
1104 <            if (tab == null || (n = tab.length) == 0) {
1105 <                n = (sc > c) ? sc : c;
1106 <                if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1107 <                    try {
1108 <                        if (table == tab) {
1109 <                            table = new Node[n];
1110 <                            sc = n - (n >>> 2);
1111 <                        }
1112 <                    } finally {
1113 <                        sizeCtl = sc;
1114 <                    }
1115 <                }
1116 <            }
1117 <            else if (c <= sc || n >= MAXIMUM_CAPACITY)
1118 <                break;
1119 <            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1120 <                try {
1121 <                    if (table == tab) {
1122 <                        table = rebuild(tab);
1123 <                        sc = (n << 1) - (n >>> 1);
1124 <                    }
1125 <                } finally {
1126 <                    sizeCtl = sc;
1127 <                }
1128 <            }
1129 <        }
1130 <    }
804 >    private transient volatile int sizeCtl;
805  
806 <    /*
807 <     * Moves and/or copies the nodes in each bin to new table. See
1134 <     * above for explanation.
1135 <     *
1136 <     * @return the new table
806 >    /**
807 >     * The next table index (plus one) to split while resizing.
808       */
809 <    private static final Node[] rebuild(Node[] tab) {
1139 <        int n = tab.length;
1140 <        Node[] nextTab = new Node[n << 1];
1141 <        Node fwd = new Node(MOVED, nextTab, null, null);
1142 <        int[] buffer = null;       // holds bins to revisit; null until needed
1143 <        Node rev = null;           // reverse forwarder; null until needed
1144 <        int nbuffered = 0;         // the number of bins in buffer list
1145 <        int bufferIndex = 0;       // buffer index of current buffered bin
1146 <        int bin = n - 1;           // current non-buffered bin or -1 if none
1147 <
1148 <        for (int i = bin;;) {      // start upwards sweep
1149 <            int fh; Node f;
1150 <            if ((f = tabAt(tab, i)) == null) {
1151 <                if (bin >= 0) {    // no lock needed (or available)
1152 <                    if (!casTabAt(tab, i, f, fwd))
1153 <                        continue;
1154 <                }
1155 <                else {             // transiently use a locked forwarding node
1156 <                    Node g = new Node(MOVED|LOCKED, nextTab, null, null);
1157 <                    if (!casTabAt(tab, i, f, g))
1158 <                        continue;
1159 <                    setTabAt(nextTab, i, null);
1160 <                    setTabAt(nextTab, i + n, null);
1161 <                    setTabAt(tab, i, fwd);
1162 <                    if (!g.casHash(MOVED|LOCKED, MOVED)) {
1163 <                        g.hash = MOVED;
1164 <                        synchronized (g) { g.notifyAll(); }
1165 <                    }
1166 <                }
1167 <            }
1168 <            else if (((fh = f.hash) & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1169 <                boolean validated = false;
1170 <                try {              // split to lo and hi lists; copying as needed
1171 <                    if (tabAt(tab, i) == f) {
1172 <                        validated = true;
1173 <                        Node e = f, lastRun = f;
1174 <                        Node lo = null, hi = null;
1175 <                        int runBit = e.hash & n;
1176 <                        for (Node p = e.next; p != null; p = p.next) {
1177 <                            int b = p.hash & n;
1178 <                            if (b != runBit) {
1179 <                                runBit = b;
1180 <                                lastRun = p;
1181 <                            }
1182 <                        }
1183 <                        if (runBit == 0)
1184 <                            lo = lastRun;
1185 <                        else
1186 <                            hi = lastRun;
1187 <                        for (Node p = e; p != lastRun; p = p.next) {
1188 <                            int ph = p.hash & HASH_BITS;
1189 <                            Object pk = p.key, pv = p.val;
1190 <                            if ((ph & n) == 0)
1191 <                                lo = new Node(ph, pk, pv, lo);
1192 <                            else
1193 <                                hi = new Node(ph, pk, pv, hi);
1194 <                        }
1195 <                        setTabAt(nextTab, i, lo);
1196 <                        setTabAt(nextTab, i + n, hi);
1197 <                        setTabAt(tab, i, fwd);
1198 <                    }
1199 <                } finally {
1200 <                    if (!f.casHash(fh | LOCKED, fh)) {
1201 <                        f.hash = fh;
1202 <                        synchronized (f) { f.notifyAll(); };
1203 <                    }
1204 <                }
1205 <                if (!validated)
1206 <                    continue;
1207 <            }
1208 <            else {
1209 <                if (buffer == null) // initialize buffer for revisits
1210 <                    buffer = new int[TRANSFER_BUFFER_SIZE];
1211 <                if (bin < 0 && bufferIndex > 0) {
1212 <                    int j = buffer[--bufferIndex];
1213 <                    buffer[bufferIndex] = i;
1214 <                    i = j;         // swap with another bin
1215 <                    continue;
1216 <                }
1217 <                if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
1218 <                    f.tryAwaitLock(tab, i);
1219 <                    continue;      // no other options -- block
1220 <                }
1221 <                if (rev == null)   // initialize reverse-forwarder
1222 <                    rev = new Node(MOVED, tab, null, null);
1223 <                if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
1224 <                    continue;      // recheck before adding to list
1225 <                buffer[nbuffered++] = i;
1226 <                setTabAt(nextTab, i, rev);     // install place-holders
1227 <                setTabAt(nextTab, i + n, rev);
1228 <            }
1229 <
1230 <            if (bin > 0)
1231 <                i = --bin;
1232 <            else if (buffer != null && nbuffered > 0) {
1233 <                bin = -1;
1234 <                i = buffer[bufferIndex = --nbuffered];
1235 <            }
1236 <            else
1237 <                return nextTab;
1238 <        }
1239 <    }
809 >    private transient volatile int transferIndex;
810  
811      /**
812 <     * Implementation for clear. Steps through each bin, removing all
1243 <     * nodes.
812 >     * Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
813       */
814 <    private final void internalClear() {
1246 <        long delta = 0L; // negative number of deletions
1247 <        int i = 0;
1248 <        Node[] tab = table;
1249 <        while (tab != null && i < tab.length) {
1250 <            int fh;
1251 <            Node f = tabAt(tab, i);
1252 <            if (f == null)
1253 <                ++i;
1254 <            else if ((fh = f.hash) == MOVED)
1255 <                tab = (Node[])f.key;
1256 <            else if ((fh & LOCKED) != 0) {
1257 <                counter.add(delta); // opportunistically update count
1258 <                delta = 0L;
1259 <                f.tryAwaitLock(tab, i);
1260 <            }
1261 <            else if (f.casHash(fh, fh | LOCKED)) {
1262 <                boolean validated = false;
1263 <                try {
1264 <                    if (tabAt(tab, i) == f) {
1265 <                        validated = true;
1266 <                        for (Node e = f; e != null; e = e.next) {
1267 <                            if (e.val != null) { // currently always true
1268 <                                e.val = null;
1269 <                                --delta;
1270 <                            }
1271 <                        }
1272 <                        setTabAt(tab, i, null);
1273 <                    }
1274 <                } finally {
1275 <                    if (!f.casHash(fh | LOCKED, fh)) {
1276 <                        f.hash = fh;
1277 <                        synchronized (f) { f.notifyAll(); };
1278 <                    }
1279 <                }
1280 <                if (validated)
1281 <                    ++i;
1282 <            }
1283 <        }
1284 <        if (delta != 0)
1285 <            counter.add(delta);
1286 <    }
1287 <
1288 <
1289 <    /* ----------------Table Traversal -------------- */
814 >    private transient volatile int cellsBusy;
815  
816      /**
817 <     * Encapsulates traversal for methods such as containsValue; also
1293 <     * serves as a base class for other iterators.
1294 <     *
1295 <     * At each step, the iterator snapshots the key ("nextKey") and
1296 <     * value ("nextVal") of a valid node (i.e., one that, at point of
1297 <     * snapshot, has a non-null user value). Because val fields can
1298 <     * change (including to null, indicating deletion), field nextVal
1299 <     * might not be accurate at point of use, but still maintains the
1300 <     * weak consistency property of holding a value that was once
1301 <     * valid.
1302 <     *
1303 <     * Internal traversals directly access these fields, as in:
1304 <     * {@code while (it.next != null) { process(it.nextKey); it.advance(); }}
1305 <     *
1306 <     * Exported iterators (subclasses of ViewIterator) extract key,
1307 <     * value, or key-value pairs as return values of Iterator.next(),
1308 <     * and encapsulate the it.next check as hasNext();
1309 <     *
1310 <     * The iterator visits once each still-valid node that was
1311 <     * reachable upon iterator construction. It might miss some that
1312 <     * were added to a bin after the bin was visited, which is OK wrt
1313 <     * consistency guarantees. Maintaining this property in the face
1314 <     * of possible ongoing resizes requires a fair amount of
1315 <     * bookkeeping state that is difficult to optimize away amidst
1316 <     * volatile accesses.  Even so, traversal maintains reasonable
1317 <     * throughput.
1318 <     *
1319 <     * Normally, iteration proceeds bin-by-bin traversing lists.
1320 <     * However, if the table has been resized, then all future steps
1321 <     * must traverse both the bin at the current index as well as at
1322 <     * (index + baseSize); and so on for further resizings. To
1323 <     * paranoically cope with potential sharing by users of iterators
1324 <     * across threads, iteration terminates if a bounds checks fails
1325 <     * for a table read.
1326 <     *
1327 <     * The range-based constructor enables creation of parallel
1328 <     * range-splitting traversals. (Not yet implemented.)
817 >     * Table of counter cells. When non-null, size is a power of 2.
818       */
819 <    static class InternalIterator {
1331 <        Node next;           // the next entry to use
1332 <        Node last;           // the last entry used
1333 <        Object nextKey;      // cached key field of next
1334 <        Object nextVal;      // cached val field of next
1335 <        Node[] tab;          // current table; updated if resized
1336 <        int index;           // index of bin to use next
1337 <        int baseIndex;       // current index of initial table
1338 <        final int baseLimit; // index bound for initial table
1339 <        final int baseSize;  // initial table size
819 >    private transient volatile CounterCell[] counterCells;
820  
821 <        /** Creates iterator for all entries in the table. */
822 <        InternalIterator(Node[] tab) {
823 <            this.tab = tab;
824 <            baseLimit = baseSize = (tab == null) ? 0 : tab.length;
1345 <            index = baseIndex = 0;
1346 <            next = null;
1347 <            advance();
1348 <        }
821 >    // views
822 >    private transient KeySetView<K,V> keySet;
823 >    private transient ValuesView<K,V> values;
824 >    private transient EntrySetView<K,V> entrySet;
825  
1350        /** Creates iterator for the given range of the table */
1351        InternalIterator(Node[] tab, int lo, int hi) {
1352            this.tab = tab;
1353            baseSize = (tab == null) ? 0 : tab.length;
1354            baseLimit = (hi <= baseSize) ? hi : baseSize;
1355            index = baseIndex = (lo >= 0) ? lo : 0;
1356            next = null;
1357            advance();
1358        }
1359
1360        /** Advances next. See above for explanation. */
1361        final void advance() {
1362            Node e = last = next;
1363            outer: do {
1364                if (e != null)                  // advance past used/skipped node
1365                    e = e.next;
1366                while (e == null) {             // get to next non-null bin
1367                    Node[] t; int b, i, n;      // checks must use locals
1368                    if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
1369                        (t = tab) == null || i >= (n = t.length))
1370                        break outer;
1371                    else if ((e = tabAt(t, i)) != null && e.hash == MOVED)
1372                        tab = (Node[])e.key;    // restarts due to null val
1373                    else                        // visit upper slots if present
1374                        index = (i += baseSize) < n ? i : (baseIndex = b + 1);
1375                }
1376                nextKey = e.key;
1377            } while ((nextVal = e.val) == null);// skip deleted or special nodes
1378            next = e;
1379        }
1380    }
826  
827      /* ---------------- Public operations -------------- */
828  
829      /**
830 <     * Creates a new, empty map with the default initial table size (16),
830 >     * Creates a new, empty map with the default initial table size (16).
831       */
832      public ConcurrentHashMapV8() {
1388        this.counter = new LongAdder();
833      }
834  
835      /**
# Line 1404 | Line 848 | public class ConcurrentHashMapV8<K, V>
848          int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
849                     MAXIMUM_CAPACITY :
850                     tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
1407        this.counter = new LongAdder();
851          this.sizeCtl = cap;
852      }
853  
# Line 1414 | Line 857 | public class ConcurrentHashMapV8<K, V>
857       * @param m the map
858       */
859      public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
1417        this.counter = new LongAdder();
860          this.sizeCtl = DEFAULT_CAPACITY;
861 <        internalPutAll(m);
861 >        putAll(m);
862      }
863  
864      /**
# Line 1457 | Line 899 | public class ConcurrentHashMapV8<K, V>
899       * nonpositive
900       */
901      public ConcurrentHashMapV8(int initialCapacity,
902 <                               float loadFactor, int concurrencyLevel) {
902 >                             float loadFactor, int concurrencyLevel) {
903          if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
904              throw new IllegalArgumentException();
905          if (initialCapacity < concurrencyLevel)   // Use at least as many bins
906              initialCapacity = concurrencyLevel;   // as estimated threads
907          long size = (long)(1.0 + (long)initialCapacity / loadFactor);
908 <        int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
909 <                   MAXIMUM_CAPACITY: tableSizeFor((int)size));
1468 <        this.counter = new LongAdder();
908 >        int cap = (size >= (long)MAXIMUM_CAPACITY) ?
909 >            MAXIMUM_CAPACITY : tableSizeFor((int)size);
910          this.sizeCtl = cap;
911      }
912  
913 <    /**
1473 <     * {@inheritDoc}
1474 <     */
1475 <    public boolean isEmpty() {
1476 <        return counter.sum() <= 0L; // ignore transient negative values
1477 <    }
913 >    // Original (since JDK1.2) Map methods
914  
915      /**
916       * {@inheritDoc}
917       */
918      public int size() {
919 <        long n = counter.sum();
919 >        long n = sumCount();
920          return ((n < 0L) ? 0 :
921                  (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
922                  (int)n);
923      }
924  
925 <    final long longSize() { // accurate version of size needed for views
926 <        long n = counter.sum();
927 <        return (n < 0L) ? 0L : n;
925 >    /**
926 >     * {@inheritDoc}
927 >     */
928 >    public boolean isEmpty() {
929 >        return sumCount() <= 0L; // ignore transient negative values
930      }
931  
932      /**
# Line 1502 | Line 940 | public class ConcurrentHashMapV8<K, V>
940       *
941       * @throws NullPointerException if the specified key is null
942       */
1505    @SuppressWarnings("unchecked")
943      public V get(Object key) {
944 <        if (key == null)
945 <            throw new NullPointerException();
946 <        return (V)internalGet(key);
944 >        Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
945 >        int h = spread(key.hashCode());
946 >        if ((tab = table) != null && (n = tab.length) > 0 &&
947 >            (e = tabAt(tab, (n - 1) & h)) != null) {
948 >            if ((eh = e.hash) == h) {
949 >                if ((ek = e.key) == key || (ek != null && key.equals(ek)))
950 >                    return e.val;
951 >            }
952 >            else if (eh < 0)
953 >                return (p = e.find(h, key)) != null ? p.val : null;
954 >            while ((e = e.next) != null) {
955 >                if (e.hash == h &&
956 >                    ((ek = e.key) == key || (ek != null && key.equals(ek))))
957 >                    return e.val;
958 >            }
959 >        }
960 >        return null;
961      }
962  
963      /**
964       * Tests if the specified object is a key in this table.
965       *
966 <     * @param  key   possible key
966 >     * @param  key possible key
967       * @return {@code true} if and only if the specified object
968       *         is a key in this table, as determined by the
969       *         {@code equals} method; {@code false} otherwise
970       * @throws NullPointerException if the specified key is null
971       */
972      public boolean containsKey(Object key) {
973 <        if (key == null)
1523 <            throw new NullPointerException();
1524 <        return internalGet(key) != null;
973 >        return get(key) != null;
974      }
975  
976      /**
# Line 1537 | Line 986 | public class ConcurrentHashMapV8<K, V>
986      public boolean containsValue(Object value) {
987          if (value == null)
988              throw new NullPointerException();
989 <        Object v;
990 <        InternalIterator it = new InternalIterator(table);
991 <        while (it.next != null) {
992 <            if ((v = it.nextVal) == value || value.equals(v))
993 <                return true;
994 <            it.advance();
989 >        Node<K,V>[] t;
990 >        if ((t = table) != null) {
991 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
992 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
993 >                V v;
994 >                if ((v = p.val) == value || (v != null && value.equals(v)))
995 >                    return true;
996 >            }
997          }
998          return false;
999      }
1000  
1001      /**
1551     * Legacy method testing if some key maps into the specified value
1552     * in this table.  This method is identical in functionality to
1553     * {@link #containsValue}, and exists solely to ensure
1554     * full compatibility with class {@link java.util.Hashtable},
1555     * which supported this method prior to introduction of the
1556     * Java Collections framework.
1557     *
1558     * @param  value a value to search for
1559     * @return {@code true} if and only if some key maps to the
1560     *         {@code value} argument in this table as
1561     *         determined by the {@code equals} method;
1562     *         {@code false} otherwise
1563     * @throws NullPointerException if the specified value is null
1564     */
1565    public boolean contains(Object value) {
1566        return containsValue(value);
1567    }
1568
1569    /**
1002       * Maps the specified key to the specified value in this table.
1003       * Neither the key nor the value can be null.
1004       *
1005 <     * <p> The value can be retrieved by calling the {@code get} method
1005 >     * <p>The value can be retrieved by calling the {@code get} method
1006       * with a key that is equal to the original key.
1007       *
1008       * @param key key with which the specified value is to be associated
# Line 1579 | Line 1011 | public class ConcurrentHashMapV8<K, V>
1011       *         {@code null} if there was no mapping for {@code key}
1012       * @throws NullPointerException if the specified key or value is null
1013       */
1582    @SuppressWarnings("unchecked")
1014      public V put(K key, V value) {
1015 <        if (key == null || value == null)
1585 <            throw new NullPointerException();
1586 <        return (V)internalPut(key, value);
1015 >        return putVal(key, value, false);
1016      }
1017  
1018 <    /**
1019 <     * {@inheritDoc}
1020 <     *
1021 <     * @return the previous value associated with the specified key,
1022 <     *         or {@code null} if there was no mapping for the key
1023 <     * @throws NullPointerException if the specified key or value is null
1024 <     */
1025 <    @SuppressWarnings("unchecked")
1026 <    public V putIfAbsent(K key, V value) {
1027 <        if (key == null || value == null)
1028 <            throw new NullPointerException();
1029 <        return (V)internalPutIfAbsent(key, value);
1018 >    /** Implementation for put and putIfAbsent */
1019 >    final V putVal(K key, V value, boolean onlyIfAbsent) {
1020 >        if (key == null || value == null) throw new NullPointerException();
1021 >        int hash = spread(key.hashCode());
1022 >        int binCount = 0;
1023 >        for (Node<K,V>[] tab = table;;) {
1024 >            Node<K,V> f; int n, i, fh;
1025 >            if (tab == null || (n = tab.length) == 0)
1026 >                tab = initTable();
1027 >            else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
1028 >                if (casTabAt(tab, i, null,
1029 >                             new Node<K,V>(hash, key, value, null)))
1030 >                    break;                   // no lock when adding to empty bin
1031 >            }
1032 >            else if ((fh = f.hash) == MOVED)
1033 >                tab = helpTransfer(tab, f);
1034 >            else {
1035 >                V oldVal = null;
1036 >                synchronized (f) {
1037 >                    if (tabAt(tab, i) == f) {
1038 >                        if (fh >= 0) {
1039 >                            binCount = 1;
1040 >                            for (Node<K,V> e = f;; ++binCount) {
1041 >                                K ek;
1042 >                                if (e.hash == hash &&
1043 >                                    ((ek = e.key) == key ||
1044 >                                     (ek != null && key.equals(ek)))) {
1045 >                                    oldVal = e.val;
1046 >                                    if (!onlyIfAbsent)
1047 >                                        e.val = value;
1048 >                                    break;
1049 >                                }
1050 >                                Node<K,V> pred = e;
1051 >                                if ((e = e.next) == null) {
1052 >                                    pred.next = new Node<K,V>(hash, key,
1053 >                                                              value, null);
1054 >                                    break;
1055 >                                }
1056 >                            }
1057 >                        }
1058 >                        else if (f instanceof TreeBin) {
1059 >                            Node<K,V> p;
1060 >                            binCount = 2;
1061 >                            if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1062 >                                                           value)) != null) {
1063 >                                oldVal = p.val;
1064 >                                if (!onlyIfAbsent)
1065 >                                    p.val = value;
1066 >                            }
1067 >                        }
1068 >                    }
1069 >                }
1070 >                if (binCount != 0) {
1071 >                    if (binCount >= TREEIFY_THRESHOLD)
1072 >                        treeifyBin(tab, i);
1073 >                    if (oldVal != null)
1074 >                        return oldVal;
1075 >                    break;
1076 >                }
1077 >            }
1078 >        }
1079 >        addCount(1L, binCount);
1080 >        return null;
1081      }
1082  
1083      /**
# Line 1608 | Line 1088 | public class ConcurrentHashMapV8<K, V>
1088       * @param m mappings to be stored in this map
1089       */
1090      public void putAll(Map<? extends K, ? extends V> m) {
1091 <        internalPutAll(m);
1092 <    }
1093 <
1614 <    /**
1615 <     * If the specified key is not already associated with a value,
1616 <     * computes its value using the given mappingFunction and
1617 <     * enters it into the map.  This is equivalent to
1618 <     * <pre> {@code
1619 <     * if (map.containsKey(key))
1620 <     *   return map.get(key);
1621 <     * value = mappingFunction.map(key);
1622 <     * map.put(key, value);
1623 <     * return value;}</pre>
1624 <     *
1625 <     * except that the action is performed atomically.  If the
1626 <     * function returns {@code null} (in which case a {@code
1627 <     * NullPointerException} is thrown), or the function itself throws
1628 <     * an (unchecked) exception, the exception is rethrown to its
1629 <     * caller, and no mapping is recorded.  Some attempted update
1630 <     * operations on this map by other threads may be blocked while
1631 <     * computation is in progress, so the computation should be short
1632 <     * and simple, and must not attempt to update any other mappings
1633 <     * of this Map. The most appropriate usage is to construct a new
1634 <     * object serving as an initial mapped value, or memoized result,
1635 <     * as in:
1636 <     *
1637 <     *  <pre> {@code
1638 <     * map.computeIfAbsent(key, new MappingFunction<K, V>() {
1639 <     *   public V map(K k) { return new Value(f(k)); }});}</pre>
1640 <     *
1641 <     * @param key key with which the specified value is to be associated
1642 <     * @param mappingFunction the function to compute a value
1643 <     * @return the current (existing or computed) value associated with
1644 <     *         the specified key.
1645 <     * @throws NullPointerException if the specified key, mappingFunction,
1646 <     *         or computed value is null
1647 <     * @throws IllegalStateException if the computation detectably
1648 <     *         attempts a recursive update to this map that would
1649 <     *         otherwise never complete
1650 <     * @throws RuntimeException or Error if the mappingFunction does so,
1651 <     *         in which case the mapping is left unestablished
1652 <     */
1653 <    @SuppressWarnings("unchecked")
1654 <    public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
1655 <        if (key == null || mappingFunction == null)
1656 <            throw new NullPointerException();
1657 <        return (V)internalComputeIfAbsent(key, mappingFunction);
1658 <    }
1659 <
1660 <    /**
1661 <     * Computes and enters a new mapping value given a key and
1662 <     * its current mapped value (or {@code null} if there is no current
1663 <     * mapping). This is equivalent to
1664 <     *  <pre> {@code
1665 <     *  map.put(key, remappingFunction.remap(key, map.get(key));
1666 <     * }</pre>
1667 <     *
1668 <     * except that the action is performed atomically.  If the
1669 <     * function returns {@code null} (in which case a {@code
1670 <     * NullPointerException} is thrown), or the function itself throws
1671 <     * an (unchecked) exception, the exception is rethrown to its
1672 <     * caller, and current mapping is left unchanged.  Some attempted
1673 <     * update operations on this map by other threads may be blocked
1674 <     * while computation is in progress, so the computation should be
1675 <     * short and simple, and must not attempt to update any other
1676 <     * mappings of this Map. For example, to either create or
1677 <     * append new messages to a value mapping:
1678 <     *
1679 <     * <pre> {@code
1680 <     * Map<Key, String> map = ...;
1681 <     * final String msg = ...;
1682 <     * map.compute(key, new RemappingFunction<Key, String>() {
1683 <     *   public String remap(Key k, String v) {
1684 <     *    return (v == null) ? msg : v + msg;});}}</pre>
1685 <     *
1686 <     * @param key key with which the specified value is to be associated
1687 <     * @param remappingFunction the function to compute a value
1688 <     * @return the new value associated with
1689 <     *         the specified key.
1690 <     * @throws NullPointerException if the specified key or remappingFunction
1691 <     *         or computed value is null
1692 <     * @throws IllegalStateException if the computation detectably
1693 <     *         attempts a recursive update to this map that would
1694 <     *         otherwise never complete
1695 <     * @throws RuntimeException or Error if the remappingFunction does so,
1696 <     *         in which case the mapping is unchanged
1697 <     */
1698 <    @SuppressWarnings("unchecked")
1699 <    public V compute(K key, RemappingFunction<? super K, V> remappingFunction) {
1700 <        if (key == null || remappingFunction == null)
1701 <            throw new NullPointerException();
1702 <        return (V)internalCompute(key, remappingFunction);
1091 >        tryPresize(m.size());
1092 >        for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1093 >            putVal(e.getKey(), e.getValue(), false);
1094      }
1095  
1096      /**
# Line 1711 | Line 1102 | public class ConcurrentHashMapV8<K, V>
1102       *         {@code null} if there was no mapping for {@code key}
1103       * @throws NullPointerException if the specified key is null
1104       */
1714    @SuppressWarnings("unchecked")
1105      public V remove(Object key) {
1106 <        if (key == null)
1717 <            throw new NullPointerException();
1718 <        return (V)internalReplace(key, null, null);
1719 <    }
1720 <
1721 <    /**
1722 <     * {@inheritDoc}
1723 <     *
1724 <     * @throws NullPointerException if the specified key is null
1725 <     */
1726 <    public boolean remove(Object key, Object value) {
1727 <        if (key == null)
1728 <            throw new NullPointerException();
1729 <        if (value == null)
1730 <            return false;
1731 <        return internalReplace(key, null, value) != null;
1106 >        return replaceNode(key, null, null);
1107      }
1108  
1109      /**
1110 <     * {@inheritDoc}
1111 <     *
1112 <     * @throws NullPointerException if any of the arguments are null
1738 <     */
1739 <    public boolean replace(K key, V oldValue, V newValue) {
1740 <        if (key == null || oldValue == null || newValue == null)
1741 <            throw new NullPointerException();
1742 <        return internalReplace(key, newValue, oldValue) != null;
1743 <    }
1744 <
1745 <    /**
1746 <     * {@inheritDoc}
1747 <     *
1748 <     * @return the previous value associated with the specified key,
1749 <     *         or {@code null} if there was no mapping for the key
1750 <     * @throws NullPointerException if the specified key or value is null
1110 >     * Implementation for the four public remove/replace methods:
1111 >     * Replaces node value with v, conditional upon match of cv if
1112 >     * non-null.  If resulting value is null, delete.
1113       */
1114 <    @SuppressWarnings("unchecked")
1115 <    public V replace(K key, V value) {
1116 <        if (key == null || value == null)
1117 <            throw new NullPointerException();
1118 <        return (V)internalReplace(key, value, null);
1114 >    final V replaceNode(Object key, V value, Object cv) {
1115 >        int hash = spread(key.hashCode());
1116 >        for (Node<K,V>[] tab = table;;) {
1117 >            Node<K,V> f; int n, i, fh;
1118 >            if (tab == null || (n = tab.length) == 0 ||
1119 >                (f = tabAt(tab, i = (n - 1) & hash)) == null)
1120 >                break;
1121 >            else if ((fh = f.hash) == MOVED)
1122 >                tab = helpTransfer(tab, f);
1123 >            else {
1124 >                V oldVal = null;
1125 >                boolean validated = false;
1126 >                synchronized (f) {
1127 >                    if (tabAt(tab, i) == f) {
1128 >                        if (fh >= 0) {
1129 >                            validated = true;
1130 >                            for (Node<K,V> e = f, pred = null;;) {
1131 >                                K ek;
1132 >                                if (e.hash == hash &&
1133 >                                    ((ek = e.key) == key ||
1134 >                                     (ek != null && key.equals(ek)))) {
1135 >                                    V ev = e.val;
1136 >                                    if (cv == null || cv == ev ||
1137 >                                        (ev != null && cv.equals(ev))) {
1138 >                                        oldVal = ev;
1139 >                                        if (value != null)
1140 >                                            e.val = value;
1141 >                                        else if (pred != null)
1142 >                                            pred.next = e.next;
1143 >                                        else
1144 >                                            setTabAt(tab, i, e.next);
1145 >                                    }
1146 >                                    break;
1147 >                                }
1148 >                                pred = e;
1149 >                                if ((e = e.next) == null)
1150 >                                    break;
1151 >                            }
1152 >                        }
1153 >                        else if (f instanceof TreeBin) {
1154 >                            validated = true;
1155 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1156 >                            TreeNode<K,V> r, p;
1157 >                            if ((r = t.root) != null &&
1158 >                                (p = r.findTreeNode(hash, key, null)) != null) {
1159 >                                V pv = p.val;
1160 >                                if (cv == null || cv == pv ||
1161 >                                    (pv != null && cv.equals(pv))) {
1162 >                                    oldVal = pv;
1163 >                                    if (value != null)
1164 >                                        p.val = value;
1165 >                                    else if (t.removeTreeNode(p))
1166 >                                        setTabAt(tab, i, untreeify(t.first));
1167 >                                }
1168 >                            }
1169 >                        }
1170 >                    }
1171 >                }
1172 >                if (validated) {
1173 >                    if (oldVal != null) {
1174 >                        if (value == null)
1175 >                            addCount(-1L, -1);
1176 >                        return oldVal;
1177 >                    }
1178 >                    break;
1179 >                }
1180 >            }
1181 >        }
1182 >        return null;
1183      }
1184  
1185      /**
1186       * Removes all of the mappings from this map.
1187       */
1188      public void clear() {
1189 <        internalClear();
1189 >        long delta = 0L; // negative number of deletions
1190 >        int i = 0;
1191 >        Node<K,V>[] tab = table;
1192 >        while (tab != null && i < tab.length) {
1193 >            int fh;
1194 >            Node<K,V> f = tabAt(tab, i);
1195 >            if (f == null)
1196 >                ++i;
1197 >            else if ((fh = f.hash) == MOVED) {
1198 >                tab = helpTransfer(tab, f);
1199 >                i = 0; // restart
1200 >            }
1201 >            else {
1202 >                synchronized (f) {
1203 >                    if (tabAt(tab, i) == f) {
1204 >                        Node<K,V> p = (fh >= 0 ? f :
1205 >                                       (f instanceof TreeBin) ?
1206 >                                       ((TreeBin<K,V>)f).first : null);
1207 >                        while (p != null) {
1208 >                            --delta;
1209 >                            p = p.next;
1210 >                        }
1211 >                        setTabAt(tab, i++, null);
1212 >                    }
1213 >                }
1214 >            }
1215 >        }
1216 >        if (delta != 0L)
1217 >            addCount(delta, -1);
1218      }
1219  
1220      /**
1221       * Returns a {@link Set} view of the keys contained in this map.
1222       * The set is backed by the map, so changes to the map are
1223 <     * reflected in the set, and vice-versa.  The set supports element
1223 >     * reflected in the set, and vice-versa. The set supports element
1224       * removal, which removes the corresponding mapping from this map,
1225       * via the {@code Iterator.remove}, {@code Set.remove},
1226       * {@code removeAll}, {@code retainAll}, and {@code clear}
# Line 1778 | Line 1232 | public class ConcurrentHashMapV8<K, V>
1232       * and guarantees to traverse elements as they existed upon
1233       * construction of the iterator, and may (but is not guaranteed to)
1234       * reflect any modifications subsequent to construction.
1235 +     *
1236 +     * @return the set view
1237       */
1238 <    public Set<K> keySet() {
1239 <        KeySet<K,V> ks = keySet;
1240 <        return (ks != null) ? ks : (keySet = new KeySet<K,V>(this));
1238 >    public KeySetView<K,V> keySet() {
1239 >        KeySetView<K,V> ks;
1240 >        return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1241      }
1242  
1243      /**
# Line 1799 | Line 1255 | public class ConcurrentHashMapV8<K, V>
1255       * and guarantees to traverse elements as they existed upon
1256       * construction of the iterator, and may (but is not guaranteed to)
1257       * reflect any modifications subsequent to construction.
1258 +     *
1259 +     * @return the collection view
1260       */
1261      public Collection<V> values() {
1262 <        Values<K,V> vs = values;
1263 <        return (vs != null) ? vs : (values = new Values<K,V>(this));
1262 >        ValuesView<K,V> vs;
1263 >        return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1264      }
1265  
1266      /**
# Line 1812 | Line 1270 | public class ConcurrentHashMapV8<K, V>
1270       * removal, which removes the corresponding mapping from the map,
1271       * via the {@code Iterator.remove}, {@code Set.remove},
1272       * {@code removeAll}, {@code retainAll}, and {@code clear}
1273 <     * operations.  It does not support the {@code add} or
1816 <     * {@code addAll} operations.
1273 >     * operations.
1274       *
1275       * <p>The view's {@code iterator} is a "weakly consistent" iterator
1276       * that will never throw {@link ConcurrentModificationException},
1277       * and guarantees to traverse elements as they existed upon
1278       * construction of the iterator, and may (but is not guaranteed to)
1279       * reflect any modifications subsequent to construction.
1823     */
1824    public Set<Map.Entry<K,V>> entrySet() {
1825        EntrySet<K,V> es = entrySet;
1826        return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
1827    }
1828
1829    /**
1830     * Returns an enumeration of the keys in this table.
1280       *
1281 <     * @return an enumeration of the keys in this table
1833 <     * @see #keySet()
1281 >     * @return the set view
1282       */
1283 <    public Enumeration<K> keys() {
1284 <        return new KeyIterator<K,V>(this);
1285 <    }
1838 <
1839 <    /**
1840 <     * Returns an enumeration of the values in this table.
1841 <     *
1842 <     * @return an enumeration of the values in this table
1843 <     * @see #values()
1844 <     */
1845 <    public Enumeration<V> elements() {
1846 <        return new ValueIterator<K,V>(this);
1283 >    public Set<Map.Entry<K,V>> entrySet() {
1284 >        EntrySetView<K,V> es;
1285 >        return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1286      }
1287  
1288      /**
# Line 1855 | Line 1294 | public class ConcurrentHashMapV8<K, V>
1294       */
1295      public int hashCode() {
1296          int h = 0;
1297 <        InternalIterator it = new InternalIterator(table);
1298 <        while (it.next != null) {
1299 <            h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
1300 <            it.advance();
1297 >        Node<K,V>[] t;
1298 >        if ((t = table) != null) {
1299 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1300 >            for (Node<K,V> p; (p = it.advance()) != null; )
1301 >                h += p.key.hashCode() ^ p.val.hashCode();
1302          }
1303          return h;
1304      }
# Line 1875 | Line 1315 | public class ConcurrentHashMapV8<K, V>
1315       * @return a string representation of this map
1316       */
1317      public String toString() {
1318 <        InternalIterator it = new InternalIterator(table);
1318 >        Node<K,V>[] t;
1319 >        int f = (t = table) == null ? 0 : t.length;
1320 >        Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1321          StringBuilder sb = new StringBuilder();
1322          sb.append('{');
1323 <        if (it.next != null) {
1323 >        Node<K,V> p;
1324 >        if ((p = it.advance()) != null) {
1325              for (;;) {
1326 <                Object k = it.nextKey, v = it.nextVal;
1326 >                K k = p.key;
1327 >                V v = p.val;
1328                  sb.append(k == this ? "(this Map)" : k);
1329                  sb.append('=');
1330                  sb.append(v == this ? "(this Map)" : v);
1331 <                it.advance();
1888 <                if (it.next == null)
1331 >                if ((p = it.advance()) == null)
1332                      break;
1333                  sb.append(',').append(' ');
1334              }
# Line 1908 | Line 1351 | public class ConcurrentHashMapV8<K, V>
1351              if (!(o instanceof Map))
1352                  return false;
1353              Map<?,?> m = (Map<?,?>) o;
1354 <            InternalIterator it = new InternalIterator(table);
1355 <            while (it.next != null) {
1356 <                Object val = it.nextVal;
1357 <                Object v = m.get(it.nextKey);
1354 >            Node<K,V>[] t;
1355 >            int f = (t = table) == null ? 0 : t.length;
1356 >            Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1357 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1358 >                V val = p.val;
1359 >                Object v = m.get(p.key);
1360                  if (v == null || (v != val && !v.equals(val)))
1361                      return false;
1917                it.advance();
1362              }
1363              for (Map.Entry<?,?> e : m.entrySet()) {
1364                  Object mk, mv, v;
1365                  if ((mk = e.getKey()) == null ||
1366                      (mv = e.getValue()) == null ||
1367 <                    (v = internalGet(mk)) == null ||
1367 >                    (v = get(mk)) == null ||
1368                      (mv != v && !mv.equals(v)))
1369                      return false;
1370              }
# Line 1928 | Line 1372 | public class ConcurrentHashMapV8<K, V>
1372          return true;
1373      }
1374  
1375 <    /* ----------------Iterators -------------- */
1375 >    /**
1376 >     * Stripped-down version of helper class used in previous version,
1377 >     * declared for the sake of serialization compatibility
1378 >     */
1379 >    static class Segment<K,V> extends ReentrantLock implements Serializable {
1380 >        private static final long serialVersionUID = 2249069246763182397L;
1381 >        final float loadFactor;
1382 >        Segment(float lf) { this.loadFactor = lf; }
1383 >    }
1384 >
1385 >    /**
1386 >     * Saves the state of the {@code ConcurrentHashMapV8} instance to a
1387 >     * stream (i.e., serializes it).
1388 >     * @param s the stream
1389 >     * @throws java.io.IOException if an I/O error occurs
1390 >     * @serialData
1391 >     * the key (Object) and value (Object)
1392 >     * for each key-value mapping, followed by a null pair.
1393 >     * The key-value mappings are emitted in no particular order.
1394 >     */
1395 >    private void writeObject(java.io.ObjectOutputStream s)
1396 >        throws java.io.IOException {
1397 >        // For serialization compatibility
1398 >        // Emulate segment calculation from previous version of this class
1399 >        int sshift = 0;
1400 >        int ssize = 1;
1401 >        while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1402 >            ++sshift;
1403 >            ssize <<= 1;
1404 >        }
1405 >        int segmentShift = 32 - sshift;
1406 >        int segmentMask = ssize - 1;
1407 >        @SuppressWarnings("unchecked") Segment<K,V>[] segments = (Segment<K,V>[])
1408 >            new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1409 >        for (int i = 0; i < segments.length; ++i)
1410 >            segments[i] = new Segment<K,V>(LOAD_FACTOR);
1411 >        s.putFields().put("segments", segments);
1412 >        s.putFields().put("segmentShift", segmentShift);
1413 >        s.putFields().put("segmentMask", segmentMask);
1414 >        s.writeFields();
1415 >
1416 >        Node<K,V>[] t;
1417 >        if ((t = table) != null) {
1418 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1419 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1420 >                s.writeObject(p.key);
1421 >                s.writeObject(p.val);
1422 >            }
1423 >        }
1424 >        s.writeObject(null);
1425 >        s.writeObject(null);
1426 >        segments = null; // throw away
1427 >    }
1428 >
1429 >    /**
1430 >     * Reconstitutes the instance from a stream (that is, deserializes it).
1431 >     * @param s the stream
1432 >     * @throws ClassNotFoundException if the class of a serialized object
1433 >     *         could not be found
1434 >     * @throws java.io.IOException if an I/O error occurs
1435 >     */
1436 >    private void readObject(java.io.ObjectInputStream s)
1437 >        throws java.io.IOException, ClassNotFoundException {
1438 >        /*
1439 >         * To improve performance in typical cases, we create nodes
1440 >         * while reading, then place in table once size is known.
1441 >         * However, we must also validate uniqueness and deal with
1442 >         * overpopulated bins while doing so, which requires
1443 >         * specialized versions of putVal mechanics.
1444 >         */
1445 >        sizeCtl = -1; // force exclusion for table construction
1446 >        s.defaultReadObject();
1447 >        long size = 0L;
1448 >        Node<K,V> p = null;
1449 >        for (;;) {
1450 >            @SuppressWarnings("unchecked") K k = (K) s.readObject();
1451 >            @SuppressWarnings("unchecked") V v = (V) s.readObject();
1452 >            if (k != null && v != null) {
1453 >                p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1454 >                ++size;
1455 >            }
1456 >            else
1457 >                break;
1458 >        }
1459 >        if (size == 0L)
1460 >            sizeCtl = 0;
1461 >        else {
1462 >            int n;
1463 >            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1464 >                n = MAXIMUM_CAPACITY;
1465 >            else {
1466 >                int sz = (int)size;
1467 >                n = tableSizeFor(sz + (sz >>> 1) + 1);
1468 >            }
1469 >            @SuppressWarnings("unchecked")
1470 >                Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1471 >            int mask = n - 1;
1472 >            long added = 0L;
1473 >            while (p != null) {
1474 >                boolean insertAtFront;
1475 >                Node<K,V> next = p.next, first;
1476 >                int h = p.hash, j = h & mask;
1477 >                if ((first = tabAt(tab, j)) == null)
1478 >                    insertAtFront = true;
1479 >                else {
1480 >                    K k = p.key;
1481 >                    if (first.hash < 0) {
1482 >                        TreeBin<K,V> t = (TreeBin<K,V>)first;
1483 >                        if (t.putTreeVal(h, k, p.val) == null)
1484 >                            ++added;
1485 >                        insertAtFront = false;
1486 >                    }
1487 >                    else {
1488 >                        int binCount = 0;
1489 >                        insertAtFront = true;
1490 >                        Node<K,V> q; K qk;
1491 >                        for (q = first; q != null; q = q.next) {
1492 >                            if (q.hash == h &&
1493 >                                ((qk = q.key) == k ||
1494 >                                 (qk != null && k.equals(qk)))) {
1495 >                                insertAtFront = false;
1496 >                                break;
1497 >                            }
1498 >                            ++binCount;
1499 >                        }
1500 >                        if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1501 >                            insertAtFront = false;
1502 >                            ++added;
1503 >                            p.next = first;
1504 >                            TreeNode<K,V> hd = null, tl = null;
1505 >                            for (q = p; q != null; q = q.next) {
1506 >                                TreeNode<K,V> t = new TreeNode<K,V>
1507 >                                    (q.hash, q.key, q.val, null, null);
1508 >                                if ((t.prev = tl) == null)
1509 >                                    hd = t;
1510 >                                else
1511 >                                    tl.next = t;
1512 >                                tl = t;
1513 >                            }
1514 >                            setTabAt(tab, j, new TreeBin<K,V>(hd));
1515 >                        }
1516 >                    }
1517 >                }
1518 >                if (insertAtFront) {
1519 >                    ++added;
1520 >                    p.next = first;
1521 >                    setTabAt(tab, j, p);
1522 >                }
1523 >                p = next;
1524 >            }
1525 >            table = tab;
1526 >            sizeCtl = n - (n >>> 2);
1527 >            baseCount = added;
1528 >        }
1529 >    }
1530 >
1531 >    // ConcurrentMap methods
1532 >
1533 >    /**
1534 >     * {@inheritDoc}
1535 >     *
1536 >     * @return the previous value associated with the specified key,
1537 >     *         or {@code null} if there was no mapping for the key
1538 >     * @throws NullPointerException if the specified key or value is null
1539 >     */
1540 >    public V putIfAbsent(K key, V value) {
1541 >        return putVal(key, value, true);
1542 >    }
1543 >
1544 >    /**
1545 >     * {@inheritDoc}
1546 >     *
1547 >     * @throws NullPointerException if the specified key is null
1548 >     */
1549 >    public boolean remove(Object key, Object value) {
1550 >        if (key == null)
1551 >            throw new NullPointerException();
1552 >        return value != null && replaceNode(key, null, value) != null;
1553 >    }
1554 >
1555 >    /**
1556 >     * {@inheritDoc}
1557 >     *
1558 >     * @throws NullPointerException if any of the arguments are null
1559 >     */
1560 >    public boolean replace(K key, V oldValue, V newValue) {
1561 >        if (key == null || oldValue == null || newValue == null)
1562 >            throw new NullPointerException();
1563 >        return replaceNode(key, newValue, oldValue) != null;
1564 >    }
1565 >
1566 >    /**
1567 >     * {@inheritDoc}
1568 >     *
1569 >     * @return the previous value associated with the specified key,
1570 >     *         or {@code null} if there was no mapping for the key
1571 >     * @throws NullPointerException if the specified key or value is null
1572 >     */
1573 >    public V replace(K key, V value) {
1574 >        if (key == null || value == null)
1575 >            throw new NullPointerException();
1576 >        return replaceNode(key, value, null);
1577 >    }
1578 >
1579 >    // Overrides of JDK8+ Map extension method defaults
1580 >
1581 >    /**
1582 >     * Returns the value to which the specified key is mapped, or the
1583 >     * given default value if this map contains no mapping for the
1584 >     * key.
1585 >     *
1586 >     * @param key the key whose associated value is to be returned
1587 >     * @param defaultValue the value to return if this map contains
1588 >     * no mapping for the given key
1589 >     * @return the mapping for the key, if present; else the default value
1590 >     * @throws NullPointerException if the specified key is null
1591 >     */
1592 >    public V getOrDefault(Object key, V defaultValue) {
1593 >        V v;
1594 >        return (v = get(key)) == null ? defaultValue : v;
1595 >    }
1596 >
1597 >    public void forEach(BiAction<? super K, ? super V> action) {
1598 >        if (action == null) throw new NullPointerException();
1599 >        Node<K,V>[] t;
1600 >        if ((t = table) != null) {
1601 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1602 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1603 >                action.apply(p.key, p.val);
1604 >            }
1605 >        }
1606 >    }
1607 >
1608 >    public void replaceAll(BiFun<? super K, ? super V, ? extends V> function) {
1609 >        if (function == null) throw new NullPointerException();
1610 >        Node<K,V>[] t;
1611 >        if ((t = table) != null) {
1612 >            Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1613 >            for (Node<K,V> p; (p = it.advance()) != null; ) {
1614 >                V oldValue = p.val;
1615 >                for (K key = p.key;;) {
1616 >                    V newValue = function.apply(key, oldValue);
1617 >                    if (newValue == null)
1618 >                        throw new NullPointerException();
1619 >                    if (replaceNode(key, newValue, oldValue) != null ||
1620 >                        (oldValue = get(key)) == null)
1621 >                        break;
1622 >                }
1623 >            }
1624 >        }
1625 >    }
1626 >
1627 >    /**
1628 >     * If the specified key is not already associated with a value,
1629 >     * attempts to compute its value using the given mapping function
1630 >     * and enters it into this map unless {@code null}.  The entire
1631 >     * method invocation is performed atomically, so the function is
1632 >     * applied at most once per key.  Some attempted update operations
1633 >     * on this map by other threads may be blocked while computation
1634 >     * is in progress, so the computation should be short and simple,
1635 >     * and must not attempt to update any other mappings of this map.
1636 >     *
1637 >     * @param key key with which the specified value is to be associated
1638 >     * @param mappingFunction the function to compute a value
1639 >     * @return the current (existing or computed) value associated with
1640 >     *         the specified key, or null if the computed value is null
1641 >     * @throws NullPointerException if the specified key or mappingFunction
1642 >     *         is null
1643 >     * @throws IllegalStateException if the computation detectably
1644 >     *         attempts a recursive update to this map that would
1645 >     *         otherwise never complete
1646 >     * @throws RuntimeException or Error if the mappingFunction does so,
1647 >     *         in which case the mapping is left unestablished
1648 >     */
1649 >    public V computeIfAbsent(K key, Fun<? super K, ? extends V> mappingFunction) {
1650 >        if (key == null || mappingFunction == null)
1651 >            throw new NullPointerException();
1652 >        int h = spread(key.hashCode());
1653 >        V val = null;
1654 >        int binCount = 0;
1655 >        for (Node<K,V>[] tab = table;;) {
1656 >            Node<K,V> f; int n, i, fh;
1657 >            if (tab == null || (n = tab.length) == 0)
1658 >                tab = initTable();
1659 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1660 >                Node<K,V> r = new ReservationNode<K,V>();
1661 >                synchronized (r) {
1662 >                    if (casTabAt(tab, i, null, r)) {
1663 >                        binCount = 1;
1664 >                        Node<K,V> node = null;
1665 >                        try {
1666 >                            if ((val = mappingFunction.apply(key)) != null)
1667 >                                node = new Node<K,V>(h, key, val, null);
1668 >                        } finally {
1669 >                            setTabAt(tab, i, node);
1670 >                        }
1671 >                    }
1672 >                }
1673 >                if (binCount != 0)
1674 >                    break;
1675 >            }
1676 >            else if ((fh = f.hash) == MOVED)
1677 >                tab = helpTransfer(tab, f);
1678 >            else {
1679 >                boolean added = false;
1680 >                synchronized (f) {
1681 >                    if (tabAt(tab, i) == f) {
1682 >                        if (fh >= 0) {
1683 >                            binCount = 1;
1684 >                            for (Node<K,V> e = f;; ++binCount) {
1685 >                                K ek; V ev;
1686 >                                if (e.hash == h &&
1687 >                                    ((ek = e.key) == key ||
1688 >                                     (ek != null && key.equals(ek)))) {
1689 >                                    val = e.val;
1690 >                                    break;
1691 >                                }
1692 >                                Node<K,V> pred = e;
1693 >                                if ((e = e.next) == null) {
1694 >                                    if ((val = mappingFunction.apply(key)) != null) {
1695 >                                        added = true;
1696 >                                        pred.next = new Node<K,V>(h, key, val, null);
1697 >                                    }
1698 >                                    break;
1699 >                                }
1700 >                            }
1701 >                        }
1702 >                        else if (f instanceof TreeBin) {
1703 >                            binCount = 2;
1704 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1705 >                            TreeNode<K,V> r, p;
1706 >                            if ((r = t.root) != null &&
1707 >                                (p = r.findTreeNode(h, key, null)) != null)
1708 >                                val = p.val;
1709 >                            else if ((val = mappingFunction.apply(key)) != null) {
1710 >                                added = true;
1711 >                                t.putTreeVal(h, key, val);
1712 >                            }
1713 >                        }
1714 >                    }
1715 >                }
1716 >                if (binCount != 0) {
1717 >                    if (binCount >= TREEIFY_THRESHOLD)
1718 >                        treeifyBin(tab, i);
1719 >                    if (!added)
1720 >                        return val;
1721 >                    break;
1722 >                }
1723 >            }
1724 >        }
1725 >        if (val != null)
1726 >            addCount(1L, binCount);
1727 >        return val;
1728 >    }
1729  
1730      /**
1731 <     * Base class for key, value, and entry iterators.  Adds a map
1732 <     * reference to InternalIterator to support Iterator.remove.
1731 >     * If the value for the specified key is present, attempts to
1732 >     * compute a new mapping given the key and its current mapped
1733 >     * value.  The entire method invocation is performed atomically.
1734 >     * Some attempted update operations on this map by other threads
1735 >     * may be blocked while computation is in progress, so the
1736 >     * computation should be short and simple, and must not attempt to
1737 >     * update any other mappings of this map.
1738 >     *
1739 >     * @param key key with which a value may be associated
1740 >     * @param remappingFunction the function to compute a value
1741 >     * @return the new value associated with the specified key, or null if none
1742 >     * @throws NullPointerException if the specified key or remappingFunction
1743 >     *         is null
1744 >     * @throws IllegalStateException if the computation detectably
1745 >     *         attempts a recursive update to this map that would
1746 >     *         otherwise never complete
1747 >     * @throws RuntimeException or Error if the remappingFunction does so,
1748 >     *         in which case the mapping is unchanged
1749       */
1750 <    static abstract class ViewIterator<K,V> extends InternalIterator {
1751 <        final ConcurrentHashMapV8<K, V> map;
1752 <        ViewIterator(ConcurrentHashMapV8<K, V> map) {
1753 <            super(map.table);
1750 >    public V computeIfPresent(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
1751 >        if (key == null || remappingFunction == null)
1752 >            throw new NullPointerException();
1753 >        int h = spread(key.hashCode());
1754 >        V val = null;
1755 >        int delta = 0;
1756 >        int binCount = 0;
1757 >        for (Node<K,V>[] tab = table;;) {
1758 >            Node<K,V> f; int n, i, fh;
1759 >            if (tab == null || (n = tab.length) == 0)
1760 >                tab = initTable();
1761 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1762 >                break;
1763 >            else if ((fh = f.hash) == MOVED)
1764 >                tab = helpTransfer(tab, f);
1765 >            else {
1766 >                synchronized (f) {
1767 >                    if (tabAt(tab, i) == f) {
1768 >                        if (fh >= 0) {
1769 >                            binCount = 1;
1770 >                            for (Node<K,V> e = f, pred = null;; ++binCount) {
1771 >                                K ek;
1772 >                                if (e.hash == h &&
1773 >                                    ((ek = e.key) == key ||
1774 >                                     (ek != null && key.equals(ek)))) {
1775 >                                    val = remappingFunction.apply(key, e.val);
1776 >                                    if (val != null)
1777 >                                        e.val = val;
1778 >                                    else {
1779 >                                        delta = -1;
1780 >                                        Node<K,V> en = e.next;
1781 >                                        if (pred != null)
1782 >                                            pred.next = en;
1783 >                                        else
1784 >                                            setTabAt(tab, i, en);
1785 >                                    }
1786 >                                    break;
1787 >                                }
1788 >                                pred = e;
1789 >                                if ((e = e.next) == null)
1790 >                                    break;
1791 >                            }
1792 >                        }
1793 >                        else if (f instanceof TreeBin) {
1794 >                            binCount = 2;
1795 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1796 >                            TreeNode<K,V> r, p;
1797 >                            if ((r = t.root) != null &&
1798 >                                (p = r.findTreeNode(h, key, null)) != null) {
1799 >                                val = remappingFunction.apply(key, p.val);
1800 >                                if (val != null)
1801 >                                    p.val = val;
1802 >                                else {
1803 >                                    delta = -1;
1804 >                                    if (t.removeTreeNode(p))
1805 >                                        setTabAt(tab, i, untreeify(t.first));
1806 >                                }
1807 >                            }
1808 >                        }
1809 >                    }
1810 >                }
1811 >                if (binCount != 0)
1812 >                    break;
1813 >            }
1814 >        }
1815 >        if (delta != 0)
1816 >            addCount((long)delta, binCount);
1817 >        return val;
1818 >    }
1819 >
1820 >    /**
1821 >     * Attempts to compute a mapping for the specified key and its
1822 >     * current mapped value (or {@code null} if there is no current
1823 >     * mapping). The entire method invocation is performed atomically.
1824 >     * Some attempted update operations on this map by other threads
1825 >     * may be blocked while computation is in progress, so the
1826 >     * computation should be short and simple, and must not attempt to
1827 >     * update any other mappings of this Map.
1828 >     *
1829 >     * @param key key with which the specified value is to be associated
1830 >     * @param remappingFunction the function to compute a value
1831 >     * @return the new value associated with the specified key, or null if none
1832 >     * @throws NullPointerException if the specified key or remappingFunction
1833 >     *         is null
1834 >     * @throws IllegalStateException if the computation detectably
1835 >     *         attempts a recursive update to this map that would
1836 >     *         otherwise never complete
1837 >     * @throws RuntimeException or Error if the remappingFunction does so,
1838 >     *         in which case the mapping is unchanged
1839 >     */
1840 >    public V compute(K key,
1841 >                     BiFun<? super K, ? super V, ? extends V> remappingFunction) {
1842 >        if (key == null || remappingFunction == null)
1843 >            throw new NullPointerException();
1844 >        int h = spread(key.hashCode());
1845 >        V val = null;
1846 >        int delta = 0;
1847 >        int binCount = 0;
1848 >        for (Node<K,V>[] tab = table;;) {
1849 >            Node<K,V> f; int n, i, fh;
1850 >            if (tab == null || (n = tab.length) == 0)
1851 >                tab = initTable();
1852 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1853 >                Node<K,V> r = new ReservationNode<K,V>();
1854 >                synchronized (r) {
1855 >                    if (casTabAt(tab, i, null, r)) {
1856 >                        binCount = 1;
1857 >                        Node<K,V> node = null;
1858 >                        try {
1859 >                            if ((val = remappingFunction.apply(key, null)) != null) {
1860 >                                delta = 1;
1861 >                                node = new Node<K,V>(h, key, val, null);
1862 >                            }
1863 >                        } finally {
1864 >                            setTabAt(tab, i, node);
1865 >                        }
1866 >                    }
1867 >                }
1868 >                if (binCount != 0)
1869 >                    break;
1870 >            }
1871 >            else if ((fh = f.hash) == MOVED)
1872 >                tab = helpTransfer(tab, f);
1873 >            else {
1874 >                synchronized (f) {
1875 >                    if (tabAt(tab, i) == f) {
1876 >                        if (fh >= 0) {
1877 >                            binCount = 1;
1878 >                            for (Node<K,V> e = f, pred = null;; ++binCount) {
1879 >                                K ek;
1880 >                                if (e.hash == h &&
1881 >                                    ((ek = e.key) == key ||
1882 >                                     (ek != null && key.equals(ek)))) {
1883 >                                    val = remappingFunction.apply(key, e.val);
1884 >                                    if (val != null)
1885 >                                        e.val = val;
1886 >                                    else {
1887 >                                        delta = -1;
1888 >                                        Node<K,V> en = e.next;
1889 >                                        if (pred != null)
1890 >                                            pred.next = en;
1891 >                                        else
1892 >                                            setTabAt(tab, i, en);
1893 >                                    }
1894 >                                    break;
1895 >                                }
1896 >                                pred = e;
1897 >                                if ((e = e.next) == null) {
1898 >                                    val = remappingFunction.apply(key, null);
1899 >                                    if (val != null) {
1900 >                                        delta = 1;
1901 >                                        pred.next =
1902 >                                            new Node<K,V>(h, key, val, null);
1903 >                                    }
1904 >                                    break;
1905 >                                }
1906 >                            }
1907 >                        }
1908 >                        else if (f instanceof TreeBin) {
1909 >                            binCount = 1;
1910 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
1911 >                            TreeNode<K,V> r, p;
1912 >                            if ((r = t.root) != null)
1913 >                                p = r.findTreeNode(h, key, null);
1914 >                            else
1915 >                                p = null;
1916 >                            V pv = (p == null) ? null : p.val;
1917 >                            val = remappingFunction.apply(key, pv);
1918 >                            if (val != null) {
1919 >                                if (p != null)
1920 >                                    p.val = val;
1921 >                                else {
1922 >                                    delta = 1;
1923 >                                    t.putTreeVal(h, key, val);
1924 >                                }
1925 >                            }
1926 >                            else if (p != null) {
1927 >                                delta = -1;
1928 >                                if (t.removeTreeNode(p))
1929 >                                    setTabAt(tab, i, untreeify(t.first));
1930 >                            }
1931 >                        }
1932 >                    }
1933 >                }
1934 >                if (binCount != 0) {
1935 >                    if (binCount >= TREEIFY_THRESHOLD)
1936 >                        treeifyBin(tab, i);
1937 >                    break;
1938 >                }
1939 >            }
1940 >        }
1941 >        if (delta != 0)
1942 >            addCount((long)delta, binCount);
1943 >        return val;
1944 >    }
1945 >
1946 >    /**
1947 >     * If the specified key is not already associated with a
1948 >     * (non-null) value, associates it with the given value.
1949 >     * Otherwise, replaces the value with the results of the given
1950 >     * remapping function, or removes if {@code null}. The entire
1951 >     * method invocation is performed atomically.  Some attempted
1952 >     * update operations on this map by other threads may be blocked
1953 >     * while computation is in progress, so the computation should be
1954 >     * short and simple, and must not attempt to update any other
1955 >     * mappings of this Map.
1956 >     *
1957 >     * @param key key with which the specified value is to be associated
1958 >     * @param value the value to use if absent
1959 >     * @param remappingFunction the function to recompute a value if present
1960 >     * @return the new value associated with the specified key, or null if none
1961 >     * @throws NullPointerException if the specified key or the
1962 >     *         remappingFunction is null
1963 >     * @throws RuntimeException or Error if the remappingFunction does so,
1964 >     *         in which case the mapping is unchanged
1965 >     */
1966 >    public V merge(K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
1967 >        if (key == null || value == null || remappingFunction == null)
1968 >            throw new NullPointerException();
1969 >        int h = spread(key.hashCode());
1970 >        V val = null;
1971 >        int delta = 0;
1972 >        int binCount = 0;
1973 >        for (Node<K,V>[] tab = table;;) {
1974 >            Node<K,V> f; int n, i, fh;
1975 >            if (tab == null || (n = tab.length) == 0)
1976 >                tab = initTable();
1977 >            else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1978 >                if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1979 >                    delta = 1;
1980 >                    val = value;
1981 >                    break;
1982 >                }
1983 >            }
1984 >            else if ((fh = f.hash) == MOVED)
1985 >                tab = helpTransfer(tab, f);
1986 >            else {
1987 >                synchronized (f) {
1988 >                    if (tabAt(tab, i) == f) {
1989 >                        if (fh >= 0) {
1990 >                            binCount = 1;
1991 >                            for (Node<K,V> e = f, pred = null;; ++binCount) {
1992 >                                K ek;
1993 >                                if (e.hash == h &&
1994 >                                    ((ek = e.key) == key ||
1995 >                                     (ek != null && key.equals(ek)))) {
1996 >                                    val = remappingFunction.apply(e.val, value);
1997 >                                    if (val != null)
1998 >                                        e.val = val;
1999 >                                    else {
2000 >                                        delta = -1;
2001 >                                        Node<K,V> en = e.next;
2002 >                                        if (pred != null)
2003 >                                            pred.next = en;
2004 >                                        else
2005 >                                            setTabAt(tab, i, en);
2006 >                                    }
2007 >                                    break;
2008 >                                }
2009 >                                pred = e;
2010 >                                if ((e = e.next) == null) {
2011 >                                    delta = 1;
2012 >                                    val = value;
2013 >                                    pred.next =
2014 >                                        new Node<K,V>(h, key, val, null);
2015 >                                    break;
2016 >                                }
2017 >                            }
2018 >                        }
2019 >                        else if (f instanceof TreeBin) {
2020 >                            binCount = 2;
2021 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
2022 >                            TreeNode<K,V> r = t.root;
2023 >                            TreeNode<K,V> p = (r == null) ? null :
2024 >                                r.findTreeNode(h, key, null);
2025 >                            val = (p == null) ? value :
2026 >                                remappingFunction.apply(p.val, value);
2027 >                            if (val != null) {
2028 >                                if (p != null)
2029 >                                    p.val = val;
2030 >                                else {
2031 >                                    delta = 1;
2032 >                                    t.putTreeVal(h, key, val);
2033 >                                }
2034 >                            }
2035 >                            else if (p != null) {
2036 >                                delta = -1;
2037 >                                if (t.removeTreeNode(p))
2038 >                                    setTabAt(tab, i, untreeify(t.first));
2039 >                            }
2040 >                        }
2041 >                    }
2042 >                }
2043 >                if (binCount != 0) {
2044 >                    if (binCount >= TREEIFY_THRESHOLD)
2045 >                        treeifyBin(tab, i);
2046 >                    break;
2047 >                }
2048 >            }
2049 >        }
2050 >        if (delta != 0)
2051 >            addCount((long)delta, binCount);
2052 >        return val;
2053 >    }
2054 >
2055 >    // Hashtable legacy methods
2056 >
2057 >    /**
2058 >     * Legacy method testing if some key maps into the specified value
2059 >     * in this table.  This method is identical in functionality to
2060 >     * {@link #containsValue(Object)}, and exists solely to ensure
2061 >     * full compatibility with class {@link java.util.Hashtable},
2062 >     * which supported this method prior to introduction of the
2063 >     * Java Collections framework.
2064 >     *
2065 >     * @param  value a value to search for
2066 >     * @return {@code true} if and only if some key maps to the
2067 >     *         {@code value} argument in this table as
2068 >     *         determined by the {@code equals} method;
2069 >     *         {@code false} otherwise
2070 >     * @throws NullPointerException if the specified value is null
2071 >     */
2072 >    @Deprecated public boolean contains(Object value) {
2073 >        return containsValue(value);
2074 >    }
2075 >
2076 >    /**
2077 >     * Returns an enumeration of the keys in this table.
2078 >     *
2079 >     * @return an enumeration of the keys in this table
2080 >     * @see #keySet()
2081 >     */
2082 >    public Enumeration<K> keys() {
2083 >        Node<K,V>[] t;
2084 >        int f = (t = table) == null ? 0 : t.length;
2085 >        return new KeyIterator<K,V>(t, f, 0, f, this);
2086 >    }
2087 >
2088 >    /**
2089 >     * Returns an enumeration of the values in this table.
2090 >     *
2091 >     * @return an enumeration of the values in this table
2092 >     * @see #values()
2093 >     */
2094 >    public Enumeration<V> elements() {
2095 >        Node<K,V>[] t;
2096 >        int f = (t = table) == null ? 0 : t.length;
2097 >        return new ValueIterator<K,V>(t, f, 0, f, this);
2098 >    }
2099 >
2100 >    // ConcurrentHashMapV8-only methods
2101 >
2102 >    /**
2103 >     * Returns the number of mappings. This method should be used
2104 >     * instead of {@link #size} because a ConcurrentHashMapV8 may
2105 >     * contain more mappings than can be represented as an int. The
2106 >     * value returned is an estimate; the actual count may differ if
2107 >     * there are concurrent insertions or removals.
2108 >     *
2109 >     * @return the number of mappings
2110 >     * @since 1.8
2111 >     */
2112 >    public long mappingCount() {
2113 >        long n = sumCount();
2114 >        return (n < 0L) ? 0L : n; // ignore transient negative values
2115 >    }
2116 >
2117 >    /**
2118 >     * Creates a new {@link Set} backed by a ConcurrentHashMapV8
2119 >     * from the given type to {@code Boolean.TRUE}.
2120 >     *
2121 >     * @return the new set
2122 >     * @since 1.8
2123 >     */
2124 >    public static <K> KeySetView<K,Boolean> newKeySet() {
2125 >        return new KeySetView<K,Boolean>
2126 >            (new ConcurrentHashMapV8<K,Boolean>(), Boolean.TRUE);
2127 >    }
2128 >
2129 >    /**
2130 >     * Creates a new {@link Set} backed by a ConcurrentHashMapV8
2131 >     * from the given type to {@code Boolean.TRUE}.
2132 >     *
2133 >     * @param initialCapacity The implementation performs internal
2134 >     * sizing to accommodate this many elements.
2135 >     * @return the new set
2136 >     * @throws IllegalArgumentException if the initial capacity of
2137 >     * elements is negative
2138 >     * @since 1.8
2139 >     */
2140 >    public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2141 >        return new KeySetView<K,Boolean>
2142 >            (new ConcurrentHashMapV8<K,Boolean>(initialCapacity), Boolean.TRUE);
2143 >    }
2144 >
2145 >    /**
2146 >     * Returns a {@link Set} view of the keys in this map, using the
2147 >     * given common mapped value for any additions (i.e., {@link
2148 >     * Collection#add} and {@link Collection#addAll(Collection)}).
2149 >     * This is of course only appropriate if it is acceptable to use
2150 >     * the same value for all additions from this view.
2151 >     *
2152 >     * @param mappedValue the mapped value to use for any additions
2153 >     * @return the set view
2154 >     * @throws NullPointerException if the mappedValue is null
2155 >     */
2156 >    public KeySetView<K,V> keySet(V mappedValue) {
2157 >        if (mappedValue == null)
2158 >            throw new NullPointerException();
2159 >        return new KeySetView<K,V>(this, mappedValue);
2160 >    }
2161 >
2162 >    /* ---------------- Special Nodes -------------- */
2163 >
2164 >    /**
2165 >     * A node inserted at head of bins during transfer operations.
2166 >     */
2167 >    static final class ForwardingNode<K,V> extends Node<K,V> {
2168 >        final Node<K,V>[] nextTable;
2169 >        ForwardingNode(Node<K,V>[] tab) {
2170 >            super(MOVED, null, null, null);
2171 >            this.nextTable = tab;
2172 >        }
2173 >
2174 >        Node<K,V> find(int h, Object k) {
2175 >            // loop to avoid arbitrarily deep recursion on forwarding nodes
2176 >            outer: for (Node<K,V>[] tab = nextTable;;) {
2177 >                Node<K,V> e; int n;
2178 >                if (k == null || tab == null || (n = tab.length) == 0 ||
2179 >                    (e = tabAt(tab, (n - 1) & h)) == null)
2180 >                    return null;
2181 >                for (;;) {
2182 >                    int eh; K ek;
2183 >                    if ((eh = e.hash) == h &&
2184 >                        ((ek = e.key) == k || (ek != null && k.equals(ek))))
2185 >                        return e;
2186 >                    if (eh < 0) {
2187 >                        if (e instanceof ForwardingNode) {
2188 >                            tab = ((ForwardingNode<K,V>)e).nextTable;
2189 >                            continue outer;
2190 >                        }
2191 >                        else
2192 >                            return e.find(h, k);
2193 >                    }
2194 >                    if ((e = e.next) == null)
2195 >                        return null;
2196 >                }
2197 >            }
2198 >        }
2199 >    }
2200 >
2201 >    /**
2202 >     * A place-holder node used in computeIfAbsent and compute
2203 >     */
2204 >    static final class ReservationNode<K,V> extends Node<K,V> {
2205 >        ReservationNode() {
2206 >            super(RESERVED, null, null, null);
2207 >        }
2208 >
2209 >        Node<K,V> find(int h, Object k) {
2210 >            return null;
2211 >        }
2212 >    }
2213 >
2214 >    /* ---------------- Table Initialization and Resizing -------------- */
2215 >
2216 >    /**
2217 >     * Returns the stamp bits for resizing a table of size n.
2218 >     * Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2219 >     */
2220 >    static final int resizeStamp(int n) {
2221 >        return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2222 >    }
2223 >
2224 >    /**
2225 >     * Initializes table, using the size recorded in sizeCtl.
2226 >     */
2227 >    private final Node<K,V>[] initTable() {
2228 >        Node<K,V>[] tab; int sc;
2229 >        while ((tab = table) == null || tab.length == 0) {
2230 >            if ((sc = sizeCtl) < 0)
2231 >                Thread.yield(); // lost initialization race; just spin
2232 >            else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2233 >                try {
2234 >                    if ((tab = table) == null || tab.length == 0) {
2235 >                        int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2236 >                        @SuppressWarnings("unchecked")
2237 >                        Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2238 >                        table = tab = nt;
2239 >                        sc = n - (n >>> 2);
2240 >                    }
2241 >                } finally {
2242 >                    sizeCtl = sc;
2243 >                }
2244 >                break;
2245 >            }
2246 >        }
2247 >        return tab;
2248 >    }
2249 >
2250 >    /**
2251 >     * Adds to count, and if table is too small and not already
2252 >     * resizing, initiates transfer. If already resizing, helps
2253 >     * perform transfer if work is available.  Rechecks occupancy
2254 >     * after a transfer to see if another resize is already needed
2255 >     * because resizings are lagging additions.
2256 >     *
2257 >     * @param x the count to add
2258 >     * @param check if <0, don't check resize, if <= 1 only check if uncontended
2259 >     */
2260 >    private final void addCount(long x, int check) {
2261 >        CounterCell[] as; long b, s;
2262 >        if ((as = counterCells) != null ||
2263 >            !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2264 >            CounterHashCode hc; CounterCell a; long v; int m;
2265 >            boolean uncontended = true;
2266 >            if ((hc = threadCounterHashCode.get()) == null ||
2267 >                as == null || (m = as.length - 1) < 0 ||
2268 >                (a = as[m & hc.code]) == null ||
2269 >                !(uncontended =
2270 >                  U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2271 >                fullAddCount(x, hc, uncontended);
2272 >                return;
2273 >            }
2274 >            if (check <= 1)
2275 >                return;
2276 >            s = sumCount();
2277 >        }
2278 >        if (check >= 0) {
2279 >            Node<K,V>[] tab, nt; int n, sc;
2280 >            while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2281 >                   (n = tab.length) < MAXIMUM_CAPACITY) {
2282 >                int rs = resizeStamp(n);
2283 >                if (sc < 0) {
2284 >                    if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2285 >                        sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2286 >                        transferIndex <= 0)
2287 >                        break;
2288 >                    if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2289 >                        transfer(tab, nt);
2290 >                }
2291 >                else if (U.compareAndSwapInt(this, SIZECTL, sc,
2292 >                                             (rs << RESIZE_STAMP_SHIFT) + 2))
2293 >                    transfer(tab, null);
2294 >                s = sumCount();
2295 >            }
2296 >        }
2297 >    }
2298 >
2299 >    /**
2300 >     * Helps transfer if a resize is in progress.
2301 >     */
2302 >    final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2303 >        Node<K,V>[] nextTab; int sc;
2304 >        if (tab != null && (f instanceof ForwardingNode) &&
2305 >            (nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2306 >            int rs = resizeStamp(tab.length);
2307 >            while (nextTab == nextTable && table == tab &&
2308 >                   (sc = sizeCtl) < 0) {
2309 >                if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2310 >                    sc == rs + MAX_RESIZERS || transferIndex <= 0)
2311 >                    break;
2312 >                if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2313 >                    transfer(tab, nextTab);
2314 >                    break;
2315 >                }
2316 >            }
2317 >            return nextTab;
2318 >        }
2319 >        return table;
2320 >    }
2321 >
2322 >    /**
2323 >     * Tries to presize table to accommodate the given number of elements.
2324 >     *
2325 >     * @param size number of elements (doesn't need to be perfectly accurate)
2326 >     */
2327 >    private final void tryPresize(int size) {
2328 >        int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2329 >            tableSizeFor(size + (size >>> 1) + 1);
2330 >        int sc;
2331 >        while ((sc = sizeCtl) >= 0) {
2332 >            Node<K,V>[] tab = table; int n;
2333 >            if (tab == null || (n = tab.length) == 0) {
2334 >                n = (sc > c) ? sc : c;
2335 >                if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2336 >                    try {
2337 >                        if (table == tab) {
2338 >                            @SuppressWarnings("unchecked")
2339 >                            Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2340 >                            table = nt;
2341 >                            sc = n - (n >>> 2);
2342 >                        }
2343 >                    } finally {
2344 >                        sizeCtl = sc;
2345 >                    }
2346 >                }
2347 >            }
2348 >            else if (c <= sc || n >= MAXIMUM_CAPACITY)
2349 >                break;
2350 >            else if (tab == table) {
2351 >                int rs = resizeStamp(n);
2352 >                if (sc < 0) {
2353 >                    Node<K,V>[] nt;
2354 >                    if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2355 >                        sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2356 >                        transferIndex <= 0)
2357 >                        break;
2358 >                    if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2359 >                        transfer(tab, nt);
2360 >                }
2361 >                else if (U.compareAndSwapInt(this, SIZECTL, sc,
2362 >                                             (rs << RESIZE_STAMP_SHIFT) + 2))
2363 >                    transfer(tab, null);
2364 >            }
2365 >        }
2366 >    }
2367 >
2368 >    /**
2369 >     * Moves and/or copies the nodes in each bin to new table. See
2370 >     * above for explanation.
2371 >     */
2372 >    private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2373 >        int n = tab.length, stride;
2374 >        if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2375 >            stride = MIN_TRANSFER_STRIDE; // subdivide range
2376 >        if (nextTab == null) {            // initiating
2377 >            try {
2378 >                @SuppressWarnings("unchecked")
2379 >                Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2380 >                nextTab = nt;
2381 >            } catch (Throwable ex) {      // try to cope with OOME
2382 >                sizeCtl = Integer.MAX_VALUE;
2383 >                return;
2384 >            }
2385 >            nextTable = nextTab;
2386 >            transferIndex = n;
2387 >        }
2388 >        int nextn = nextTab.length;
2389 >        ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2390 >        boolean advance = true;
2391 >        boolean finishing = false; // to ensure sweep before committing nextTab
2392 >        for (int i = 0, bound = 0;;) {
2393 >            Node<K,V> f; int fh;
2394 >            while (advance) {
2395 >                int nextIndex, nextBound;
2396 >                if (--i >= bound || finishing)
2397 >                    advance = false;
2398 >                else if ((nextIndex = transferIndex) <= 0) {
2399 >                    i = -1;
2400 >                    advance = false;
2401 >                }
2402 >                else if (U.compareAndSwapInt
2403 >                         (this, TRANSFERINDEX, nextIndex,
2404 >                          nextBound = (nextIndex > stride ?
2405 >                                       nextIndex - stride : 0))) {
2406 >                    bound = nextBound;
2407 >                    i = nextIndex - 1;
2408 >                    advance = false;
2409 >                }
2410 >            }
2411 >            if (i < 0 || i >= n || i + n >= nextn) {
2412 >                int sc;
2413 >                if (finishing) {
2414 >                    nextTable = null;
2415 >                    table = nextTab;
2416 >                    sizeCtl = (n << 1) - (n >>> 1);
2417 >                    return;
2418 >                }
2419 >                if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2420 >                    if ((sc - 2) != resizeStamp(n))
2421 >                        return;
2422 >                    finishing = advance = true;
2423 >                    i = n; // recheck before commit
2424 >                }
2425 >            }
2426 >            else if ((f = tabAt(tab, i)) == null)
2427 >                advance = casTabAt(tab, i, null, fwd);
2428 >            else if ((fh = f.hash) == MOVED)
2429 >                advance = true; // already processed
2430 >            else {
2431 >                synchronized (f) {
2432 >                    if (tabAt(tab, i) == f) {
2433 >                        Node<K,V> ln, hn;
2434 >                        if (fh >= 0) {
2435 >                            int runBit = fh & n;
2436 >                            Node<K,V> lastRun = f;
2437 >                            for (Node<K,V> p = f.next; p != null; p = p.next) {
2438 >                                int b = p.hash & n;
2439 >                                if (b != runBit) {
2440 >                                    runBit = b;
2441 >                                    lastRun = p;
2442 >                                }
2443 >                            }
2444 >                            if (runBit == 0) {
2445 >                                ln = lastRun;
2446 >                                hn = null;
2447 >                            }
2448 >                            else {
2449 >                                hn = lastRun;
2450 >                                ln = null;
2451 >                            }
2452 >                            for (Node<K,V> p = f; p != lastRun; p = p.next) {
2453 >                                int ph = p.hash; K pk = p.key; V pv = p.val;
2454 >                                if ((ph & n) == 0)
2455 >                                    ln = new Node<K,V>(ph, pk, pv, ln);
2456 >                                else
2457 >                                    hn = new Node<K,V>(ph, pk, pv, hn);
2458 >                            }
2459 >                            setTabAt(nextTab, i, ln);
2460 >                            setTabAt(nextTab, i + n, hn);
2461 >                            setTabAt(tab, i, fwd);
2462 >                            advance = true;
2463 >                        }
2464 >                        else if (f instanceof TreeBin) {
2465 >                            TreeBin<K,V> t = (TreeBin<K,V>)f;
2466 >                            TreeNode<K,V> lo = null, loTail = null;
2467 >                            TreeNode<K,V> hi = null, hiTail = null;
2468 >                            int lc = 0, hc = 0;
2469 >                            for (Node<K,V> e = t.first; e != null; e = e.next) {
2470 >                                int h = e.hash;
2471 >                                TreeNode<K,V> p = new TreeNode<K,V>
2472 >                                    (h, e.key, e.val, null, null);
2473 >                                if ((h & n) == 0) {
2474 >                                    if ((p.prev = loTail) == null)
2475 >                                        lo = p;
2476 >                                    else
2477 >                                        loTail.next = p;
2478 >                                    loTail = p;
2479 >                                    ++lc;
2480 >                                }
2481 >                                else {
2482 >                                    if ((p.prev = hiTail) == null)
2483 >                                        hi = p;
2484 >                                    else
2485 >                                        hiTail.next = p;
2486 >                                    hiTail = p;
2487 >                                    ++hc;
2488 >                                }
2489 >                            }
2490 >                            ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2491 >                                (hc != 0) ? new TreeBin<K,V>(lo) : t;
2492 >                            hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2493 >                                (lc != 0) ? new TreeBin<K,V>(hi) : t;
2494 >                            setTabAt(nextTab, i, ln);
2495 >                            setTabAt(nextTab, i + n, hn);
2496 >                            setTabAt(tab, i, fwd);
2497 >                            advance = true;
2498 >                        }
2499 >                    }
2500 >                }
2501 >            }
2502 >        }
2503 >    }
2504 >
2505 >    /* ---------------- Conversion from/to TreeBins -------------- */
2506 >
2507 >    /**
2508 >     * Replaces all linked nodes in bin at given index unless table is
2509 >     * too small, in which case resizes instead.
2510 >     */
2511 >    private final void treeifyBin(Node<K,V>[] tab, int index) {
2512 >        Node<K,V> b; int n, sc;
2513 >        if (tab != null) {
2514 >            if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2515 >                tryPresize(n << 1);
2516 >            else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2517 >                synchronized (b) {
2518 >                    if (tabAt(tab, index) == b) {
2519 >                        TreeNode<K,V> hd = null, tl = null;
2520 >                        for (Node<K,V> e = b; e != null; e = e.next) {
2521 >                            TreeNode<K,V> p =
2522 >                                new TreeNode<K,V>(e.hash, e.key, e.val,
2523 >                                                  null, null);
2524 >                            if ((p.prev = tl) == null)
2525 >                                hd = p;
2526 >                            else
2527 >                                tl.next = p;
2528 >                            tl = p;
2529 >                        }
2530 >                        setTabAt(tab, index, new TreeBin<K,V>(hd));
2531 >                    }
2532 >                }
2533 >            }
2534 >        }
2535 >    }
2536 >
2537 >    /**
2538 >     * Returns a list on non-TreeNodes replacing those in given list.
2539 >     */
2540 >    static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2541 >        Node<K,V> hd = null, tl = null;
2542 >        for (Node<K,V> q = b; q != null; q = q.next) {
2543 >            Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2544 >            if (tl == null)
2545 >                hd = p;
2546 >            else
2547 >                tl.next = p;
2548 >            tl = p;
2549 >        }
2550 >        return hd;
2551 >    }
2552 >
2553 >    /* ---------------- TreeNodes -------------- */
2554 >
2555 >    /**
2556 >     * Nodes for use in TreeBins
2557 >     */
2558 >    static final class TreeNode<K,V> extends Node<K,V> {
2559 >        TreeNode<K,V> parent;  // red-black tree links
2560 >        TreeNode<K,V> left;
2561 >        TreeNode<K,V> right;
2562 >        TreeNode<K,V> prev;    // needed to unlink next upon deletion
2563 >        boolean red;
2564 >
2565 >        TreeNode(int hash, K key, V val, Node<K,V> next,
2566 >                 TreeNode<K,V> parent) {
2567 >            super(hash, key, val, next);
2568 >            this.parent = parent;
2569 >        }
2570 >
2571 >        Node<K,V> find(int h, Object k) {
2572 >            return findTreeNode(h, k, null);
2573 >        }
2574 >
2575 >        /**
2576 >         * Returns the TreeNode (or null if not found) for the given key
2577 >         * starting at given root.
2578 >         */
2579 >        final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2580 >            if (k != null) {
2581 >                TreeNode<K,V> p = this;
2582 >                do  {
2583 >                    int ph, dir; K pk; TreeNode<K,V> q;
2584 >                    TreeNode<K,V> pl = p.left, pr = p.right;
2585 >                    if ((ph = p.hash) > h)
2586 >                        p = pl;
2587 >                    else if (ph < h)
2588 >                        p = pr;
2589 >                    else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2590 >                        return p;
2591 >                    else if (pl == null)
2592 >                        p = pr;
2593 >                    else if (pr == null)
2594 >                        p = pl;
2595 >                    else if ((kc != null ||
2596 >                              (kc = comparableClassFor(k)) != null) &&
2597 >                             (dir = compareComparables(kc, k, pk)) != 0)
2598 >                        p = (dir < 0) ? pl : pr;
2599 >                    else if ((q = pr.findTreeNode(h, k, kc)) != null)
2600 >                        return q;
2601 >                    else
2602 >                        p = pl;
2603 >                } while (p != null);
2604 >            }
2605 >            return null;
2606 >        }
2607 >    }
2608 >
2609 >    /* ---------------- TreeBins -------------- */
2610 >
2611 >    /**
2612 >     * TreeNodes used at the heads of bins. TreeBins do not hold user
2613 >     * keys or values, but instead point to list of TreeNodes and
2614 >     * their root. They also maintain a parasitic read-write lock
2615 >     * forcing writers (who hold bin lock) to wait for readers (who do
2616 >     * not) to complete before tree restructuring operations.
2617 >     */
2618 >    static final class TreeBin<K,V> extends Node<K,V> {
2619 >        TreeNode<K,V> root;
2620 >        volatile TreeNode<K,V> first;
2621 >        volatile Thread waiter;
2622 >        volatile int lockState;
2623 >        // values for lockState
2624 >        static final int WRITER = 1; // set while holding write lock
2625 >        static final int WAITER = 2; // set when waiting for write lock
2626 >        static final int READER = 4; // increment value for setting read lock
2627 >
2628 >        /**
2629 >         * Tie-breaking utility for ordering insertions when equal
2630 >         * hashCodes and non-comparable. We don't require a total
2631 >         * order, just a consistent insertion rule to maintain
2632 >         * equivalence across rebalancings. Tie-breaking further than
2633 >         * necessary simplifies testing a bit.
2634 >         */
2635 >        static int tieBreakOrder(Object a, Object b) {
2636 >            int d;
2637 >            if (a == null || b == null ||
2638 >                (d = a.getClass().getName().
2639 >                 compareTo(b.getClass().getName())) == 0)
2640 >                d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2641 >                     -1 : 1);
2642 >            return d;
2643 >        }
2644 >
2645 >        /**
2646 >         * Creates bin with initial set of nodes headed by b.
2647 >         */
2648 >        TreeBin(TreeNode<K,V> b) {
2649 >            super(TREEBIN, null, null, null);
2650 >            this.first = b;
2651 >            TreeNode<K,V> r = null;
2652 >            for (TreeNode<K,V> x = b, next; x != null; x = next) {
2653 >                next = (TreeNode<K,V>)x.next;
2654 >                x.left = x.right = null;
2655 >                if (r == null) {
2656 >                    x.parent = null;
2657 >                    x.red = false;
2658 >                    r = x;
2659 >                }
2660 >                else {
2661 >                    K k = x.key;
2662 >                    int h = x.hash;
2663 >                    Class<?> kc = null;
2664 >                    for (TreeNode<K,V> p = r;;) {
2665 >                        int dir, ph;
2666 >                        K pk = p.key;
2667 >                        if ((ph = p.hash) > h)
2668 >                            dir = -1;
2669 >                        else if (ph < h)
2670 >                            dir = 1;
2671 >                        else if ((kc == null &&
2672 >                                  (kc = comparableClassFor(k)) == null) ||
2673 >                                 (dir = compareComparables(kc, k, pk)) == 0)
2674 >                            dir = tieBreakOrder(k, pk);
2675 >                            TreeNode<K,V> xp = p;
2676 >                        if ((p = (dir <= 0) ? p.left : p.right) == null) {
2677 >                            x.parent = xp;
2678 >                            if (dir <= 0)
2679 >                                xp.left = x;
2680 >                            else
2681 >                                xp.right = x;
2682 >                            r = balanceInsertion(r, x);
2683 >                            break;
2684 >                        }
2685 >                    }
2686 >                }
2687 >            }
2688 >            this.root = r;
2689 >            assert checkInvariants(root);
2690 >        }
2691 >
2692 >        /**
2693 >         * Acquires write lock for tree restructuring.
2694 >         */
2695 >        private final void lockRoot() {
2696 >            if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2697 >                contendedLock(); // offload to separate method
2698 >        }
2699 >
2700 >        /**
2701 >         * Releases write lock for tree restructuring.
2702 >         */
2703 >        private final void unlockRoot() {
2704 >            lockState = 0;
2705 >        }
2706 >
2707 >        /**
2708 >         * Possibly blocks awaiting root lock.
2709 >         */
2710 >        private final void contendedLock() {
2711 >            boolean waiting = false;
2712 >            for (int s;;) {
2713 >                if (((s = lockState) & ~WAITER) == 0) {
2714 >                    if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2715 >                        if (waiting)
2716 >                            waiter = null;
2717 >                        return;
2718 >                    }
2719 >                }
2720 >                else if ((s & WAITER) == 0) {
2721 >                    if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2722 >                        waiting = true;
2723 >                        waiter = Thread.currentThread();
2724 >                    }
2725 >                }
2726 >                else if (waiting)
2727 >                    LockSupport.park(this);
2728 >            }
2729 >        }
2730 >
2731 >        /**
2732 >         * Returns matching node or null if none. Tries to search
2733 >         * using tree comparisons from root, but continues linear
2734 >         * search when lock not available.
2735 >         */
2736 >        final Node<K,V> find(int h, Object k) {
2737 >            if (k != null) {
2738 >                for (Node<K,V> e = first; e != null; ) {
2739 >                    int s; K ek;
2740 >                    if (((s = lockState) & (WAITER|WRITER)) != 0) {
2741 >                        if (e.hash == h &&
2742 >                            ((ek = e.key) == k || (ek != null && k.equals(ek))))
2743 >                            return e;
2744 >                        e = e.next;
2745 >                    }
2746 >                    else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2747 >                                                 s + READER)) {
2748 >                        TreeNode<K,V> r, p;
2749 >                        try {
2750 >                            p = ((r = root) == null ? null :
2751 >                                 r.findTreeNode(h, k, null));
2752 >                        } finally {
2753 >                            Thread w;
2754 >                            int ls;
2755 >                            do {} while (!U.compareAndSwapInt
2756 >                                         (this, LOCKSTATE,
2757 >                                          ls = lockState, ls - READER));
2758 >                            if (ls == (READER|WAITER) && (w = waiter) != null)
2759 >                                LockSupport.unpark(w);
2760 >                        }
2761 >                        return p;
2762 >                    }
2763 >                }
2764 >            }
2765 >            return null;
2766 >        }
2767 >
2768 >        /**
2769 >         * Finds or adds a node.
2770 >         * @return null if added
2771 >         */
2772 >        final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2773 >            Class<?> kc = null;
2774 >            boolean searched = false;
2775 >            for (TreeNode<K,V> p = root;;) {
2776 >                int dir, ph; K pk;
2777 >                if (p == null) {
2778 >                    first = root = new TreeNode<K,V>(h, k, v, null, null);
2779 >                    break;
2780 >                }
2781 >                else if ((ph = p.hash) > h)
2782 >                    dir = -1;
2783 >                else if (ph < h)
2784 >                    dir = 1;
2785 >                else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2786 >                    return p;
2787 >                else if ((kc == null &&
2788 >                          (kc = comparableClassFor(k)) == null) ||
2789 >                         (dir = compareComparables(kc, k, pk)) == 0) {
2790 >                    if (!searched) {
2791 >                        TreeNode<K,V> q, ch;
2792 >                        searched = true;
2793 >                        if (((ch = p.left) != null &&
2794 >                             (q = ch.findTreeNode(h, k, kc)) != null) ||
2795 >                            ((ch = p.right) != null &&
2796 >                             (q = ch.findTreeNode(h, k, kc)) != null))
2797 >                            return q;
2798 >                    }
2799 >                    dir = tieBreakOrder(k, pk);
2800 >                }
2801 >
2802 >                TreeNode<K,V> xp = p;
2803 >                if ((p = (dir <= 0) ? p.left : p.right) == null) {
2804 >                    TreeNode<K,V> x, f = first;
2805 >                    first = x = new TreeNode<K,V>(h, k, v, f, xp);
2806 >                    if (f != null)
2807 >                        f.prev = x;
2808 >                    if (dir <= 0)
2809 >                        xp.left = x;
2810 >                    else
2811 >                        xp.right = x;
2812 >                    if (!xp.red)
2813 >                        x.red = true;
2814 >                    else {
2815 >                        lockRoot();
2816 >                        try {
2817 >                            root = balanceInsertion(root, x);
2818 >                        } finally {
2819 >                            unlockRoot();
2820 >                        }
2821 >                    }
2822 >                    break;
2823 >                }
2824 >            }
2825 >            assert checkInvariants(root);
2826 >            return null;
2827 >        }
2828 >
2829 >        /**
2830 >         * Removes the given node, that must be present before this
2831 >         * call.  This is messier than typical red-black deletion code
2832 >         * because we cannot swap the contents of an interior node
2833 >         * with a leaf successor that is pinned by "next" pointers
2834 >         * that are accessible independently of lock. So instead we
2835 >         * swap the tree linkages.
2836 >         *
2837 >         * @return true if now too small, so should be untreeified
2838 >         */
2839 >        final boolean removeTreeNode(TreeNode<K,V> p) {
2840 >            TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2841 >            TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2842 >            TreeNode<K,V> r, rl;
2843 >            if (pred == null)
2844 >                first = next;
2845 >            else
2846 >                pred.next = next;
2847 >            if (next != null)
2848 >                next.prev = pred;
2849 >            if (first == null) {
2850 >                root = null;
2851 >                return true;
2852 >            }
2853 >            if ((r = root) == null || r.right == null || // too small
2854 >                (rl = r.left) == null || rl.left == null)
2855 >                return true;
2856 >            lockRoot();
2857 >            try {
2858 >                TreeNode<K,V> replacement;
2859 >                TreeNode<K,V> pl = p.left;
2860 >                TreeNode<K,V> pr = p.right;
2861 >                if (pl != null && pr != null) {
2862 >                    TreeNode<K,V> s = pr, sl;
2863 >                    while ((sl = s.left) != null) // find successor
2864 >                        s = sl;
2865 >                    boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2866 >                    TreeNode<K,V> sr = s.right;
2867 >                    TreeNode<K,V> pp = p.parent;
2868 >                    if (s == pr) { // p was s's direct parent
2869 >                        p.parent = s;
2870 >                        s.right = p;
2871 >                    }
2872 >                    else {
2873 >                        TreeNode<K,V> sp = s.parent;
2874 >                        if ((p.parent = sp) != null) {
2875 >                            if (s == sp.left)
2876 >                                sp.left = p;
2877 >                            else
2878 >                                sp.right = p;
2879 >                        }
2880 >                        if ((s.right = pr) != null)
2881 >                            pr.parent = s;
2882 >                    }
2883 >                    p.left = null;
2884 >                    if ((p.right = sr) != null)
2885 >                        sr.parent = p;
2886 >                    if ((s.left = pl) != null)
2887 >                        pl.parent = s;
2888 >                    if ((s.parent = pp) == null)
2889 >                        r = s;
2890 >                    else if (p == pp.left)
2891 >                        pp.left = s;
2892 >                    else
2893 >                        pp.right = s;
2894 >                    if (sr != null)
2895 >                        replacement = sr;
2896 >                    else
2897 >                        replacement = p;
2898 >                }
2899 >                else if (pl != null)
2900 >                    replacement = pl;
2901 >                else if (pr != null)
2902 >                    replacement = pr;
2903 >                else
2904 >                    replacement = p;
2905 >                if (replacement != p) {
2906 >                    TreeNode<K,V> pp = replacement.parent = p.parent;
2907 >                    if (pp == null)
2908 >                        r = replacement;
2909 >                    else if (p == pp.left)
2910 >                        pp.left = replacement;
2911 >                    else
2912 >                        pp.right = replacement;
2913 >                    p.left = p.right = p.parent = null;
2914 >                }
2915 >
2916 >                root = (p.red) ? r : balanceDeletion(r, replacement);
2917 >
2918 >                if (p == replacement) {  // detach pointers
2919 >                    TreeNode<K,V> pp;
2920 >                    if ((pp = p.parent) != null) {
2921 >                        if (p == pp.left)
2922 >                            pp.left = null;
2923 >                        else if (p == pp.right)
2924 >                            pp.right = null;
2925 >                        p.parent = null;
2926 >                    }
2927 >                }
2928 >            } finally {
2929 >                unlockRoot();
2930 >            }
2931 >            assert checkInvariants(root);
2932 >            return false;
2933 >        }
2934 >
2935 >        /* ------------------------------------------------------------ */
2936 >        // Red-black tree methods, all adapted from CLR
2937 >
2938 >        static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2939 >                                              TreeNode<K,V> p) {
2940 >            TreeNode<K,V> r, pp, rl;
2941 >            if (p != null && (r = p.right) != null) {
2942 >                if ((rl = p.right = r.left) != null)
2943 >                    rl.parent = p;
2944 >                if ((pp = r.parent = p.parent) == null)
2945 >                    (root = r).red = false;
2946 >                else if (pp.left == p)
2947 >                    pp.left = r;
2948 >                else
2949 >                    pp.right = r;
2950 >                r.left = p;
2951 >                p.parent = r;
2952 >            }
2953 >            return root;
2954 >        }
2955 >
2956 >        static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2957 >                                               TreeNode<K,V> p) {
2958 >            TreeNode<K,V> l, pp, lr;
2959 >            if (p != null && (l = p.left) != null) {
2960 >                if ((lr = p.left = l.right) != null)
2961 >                    lr.parent = p;
2962 >                if ((pp = l.parent = p.parent) == null)
2963 >                    (root = l).red = false;
2964 >                else if (pp.right == p)
2965 >                    pp.right = l;
2966 >                else
2967 >                    pp.left = l;
2968 >                l.right = p;
2969 >                p.parent = l;
2970 >            }
2971 >            return root;
2972 >        }
2973 >
2974 >        static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
2975 >                                                    TreeNode<K,V> x) {
2976 >            x.red = true;
2977 >            for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
2978 >                if ((xp = x.parent) == null) {
2979 >                    x.red = false;
2980 >                    return x;
2981 >                }
2982 >                else if (!xp.red || (xpp = xp.parent) == null)
2983 >                    return root;
2984 >                if (xp == (xppl = xpp.left)) {
2985 >                    if ((xppr = xpp.right) != null && xppr.red) {
2986 >                        xppr.red = false;
2987 >                        xp.red = false;
2988 >                        xpp.red = true;
2989 >                        x = xpp;
2990 >                    }
2991 >                    else {
2992 >                        if (x == xp.right) {
2993 >                            root = rotateLeft(root, x = xp);
2994 >                            xpp = (xp = x.parent) == null ? null : xp.parent;
2995 >                        }
2996 >                        if (xp != null) {
2997 >                            xp.red = false;
2998 >                            if (xpp != null) {
2999 >                                xpp.red = true;
3000 >                                root = rotateRight(root, xpp);
3001 >                            }
3002 >                        }
3003 >                    }
3004 >                }
3005 >                else {
3006 >                    if (xppl != null && xppl.red) {
3007 >                        xppl.red = false;
3008 >                        xp.red = false;
3009 >                        xpp.red = true;
3010 >                        x = xpp;
3011 >                    }
3012 >                    else {
3013 >                        if (x == xp.left) {
3014 >                            root = rotateRight(root, x = xp);
3015 >                            xpp = (xp = x.parent) == null ? null : xp.parent;
3016 >                        }
3017 >                        if (xp != null) {
3018 >                            xp.red = false;
3019 >                            if (xpp != null) {
3020 >                                xpp.red = true;
3021 >                                root = rotateLeft(root, xpp);
3022 >                            }
3023 >                        }
3024 >                    }
3025 >                }
3026 >            }
3027 >        }
3028 >
3029 >        static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3030 >                                                   TreeNode<K,V> x) {
3031 >            for (TreeNode<K,V> xp, xpl, xpr;;)  {
3032 >                if (x == null || x == root)
3033 >                    return root;
3034 >                else if ((xp = x.parent) == null) {
3035 >                    x.red = false;
3036 >                    return x;
3037 >                }
3038 >                else if (x.red) {
3039 >                    x.red = false;
3040 >                    return root;
3041 >                }
3042 >                else if ((xpl = xp.left) == x) {
3043 >                    if ((xpr = xp.right) != null && xpr.red) {
3044 >                        xpr.red = false;
3045 >                        xp.red = true;
3046 >                        root = rotateLeft(root, xp);
3047 >                        xpr = (xp = x.parent) == null ? null : xp.right;
3048 >                    }
3049 >                    if (xpr == null)
3050 >                        x = xp;
3051 >                    else {
3052 >                        TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3053 >                        if ((sr == null || !sr.red) &&
3054 >                            (sl == null || !sl.red)) {
3055 >                            xpr.red = true;
3056 >                            x = xp;
3057 >                        }
3058 >                        else {
3059 >                            if (sr == null || !sr.red) {
3060 >                                if (sl != null)
3061 >                                    sl.red = false;
3062 >                                xpr.red = true;
3063 >                                root = rotateRight(root, xpr);
3064 >                                xpr = (xp = x.parent) == null ?
3065 >                                    null : xp.right;
3066 >                            }
3067 >                            if (xpr != null) {
3068 >                                xpr.red = (xp == null) ? false : xp.red;
3069 >                                if ((sr = xpr.right) != null)
3070 >                                    sr.red = false;
3071 >                            }
3072 >                            if (xp != null) {
3073 >                                xp.red = false;
3074 >                                root = rotateLeft(root, xp);
3075 >                            }
3076 >                            x = root;
3077 >                        }
3078 >                    }
3079 >                }
3080 >                else { // symmetric
3081 >                    if (xpl != null && xpl.red) {
3082 >                        xpl.red = false;
3083 >                        xp.red = true;
3084 >                        root = rotateRight(root, xp);
3085 >                        xpl = (xp = x.parent) == null ? null : xp.left;
3086 >                    }
3087 >                    if (xpl == null)
3088 >                        x = xp;
3089 >                    else {
3090 >                        TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3091 >                        if ((sl == null || !sl.red) &&
3092 >                            (sr == null || !sr.red)) {
3093 >                            xpl.red = true;
3094 >                            x = xp;
3095 >                        }
3096 >                        else {
3097 >                            if (sl == null || !sl.red) {
3098 >                                if (sr != null)
3099 >                                    sr.red = false;
3100 >                                xpl.red = true;
3101 >                                root = rotateLeft(root, xpl);
3102 >                                xpl = (xp = x.parent) == null ?
3103 >                                    null : xp.left;
3104 >                            }
3105 >                            if (xpl != null) {
3106 >                                xpl.red = (xp == null) ? false : xp.red;
3107 >                                if ((sl = xpl.left) != null)
3108 >                                    sl.red = false;
3109 >                            }
3110 >                            if (xp != null) {
3111 >                                xp.red = false;
3112 >                                root = rotateRight(root, xp);
3113 >                            }
3114 >                            x = root;
3115 >                        }
3116 >                    }
3117 >                }
3118 >            }
3119 >        }
3120 >
3121 >        /**
3122 >         * Recursive invariant check
3123 >         */
3124 >        static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3125 >            TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3126 >                tb = t.prev, tn = (TreeNode<K,V>)t.next;
3127 >            if (tb != null && tb.next != t)
3128 >                return false;
3129 >            if (tn != null && tn.prev != t)
3130 >                return false;
3131 >            if (tp != null && t != tp.left && t != tp.right)
3132 >                return false;
3133 >            if (tl != null && (tl.parent != t || tl.hash > t.hash))
3134 >                return false;
3135 >            if (tr != null && (tr.parent != t || tr.hash < t.hash))
3136 >                return false;
3137 >            if (t.red && tl != null && tl.red && tr != null && tr.red)
3138 >                return false;
3139 >            if (tl != null && !checkInvariants(tl))
3140 >                return false;
3141 >            if (tr != null && !checkInvariants(tr))
3142 >                return false;
3143 >            return true;
3144 >        }
3145 >
3146 >        private static final sun.misc.Unsafe U;
3147 >        private static final long LOCKSTATE;
3148 >        static {
3149 >            try {
3150 >                U = getUnsafe();
3151 >                Class<?> k = TreeBin.class;
3152 >                LOCKSTATE = U.objectFieldOffset
3153 >                    (k.getDeclaredField("lockState"));
3154 >            } catch (Exception e) {
3155 >                throw new Error(e);
3156 >            }
3157 >        }
3158 >    }
3159 >
3160 >    /* ----------------Table Traversal -------------- */
3161 >
3162 >    /**
3163 >     * Records the table, its length, and current traversal index for a
3164 >     * traverser that must process a region of a forwarded table before
3165 >     * proceeding with current table.
3166 >     */
3167 >    static final class TableStack<K,V> {
3168 >        int length;
3169 >        int index;
3170 >        Node<K,V>[] tab;
3171 >        TableStack<K,V> next;
3172 >    }
3173 >
3174 >    /**
3175 >     * Encapsulates traversal for methods such as containsValue; also
3176 >     * serves as a base class for other iterators and spliterators.
3177 >     *
3178 >     * Method advance visits once each still-valid node that was
3179 >     * reachable upon iterator construction. It might miss some that
3180 >     * were added to a bin after the bin was visited, which is OK wrt
3181 >     * consistency guarantees. Maintaining this property in the face
3182 >     * of possible ongoing resizes requires a fair amount of
3183 >     * bookkeeping state that is difficult to optimize away amidst
3184 >     * volatile accesses.  Even so, traversal maintains reasonable
3185 >     * throughput.
3186 >     *
3187 >     * Normally, iteration proceeds bin-by-bin traversing lists.
3188 >     * However, if the table has been resized, then all future steps
3189 >     * must traverse both the bin at the current index as well as at
3190 >     * (index + baseSize); and so on for further resizings. To
3191 >     * paranoically cope with potential sharing by users of iterators
3192 >     * across threads, iteration terminates if a bounds checks fails
3193 >     * for a table read.
3194 >     */
3195 >    static class Traverser<K,V> {
3196 >        Node<K,V>[] tab;        // current table; updated if resized
3197 >        Node<K,V> next;         // the next entry to use
3198 >        TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3199 >        int index;              // index of bin to use next
3200 >        int baseIndex;          // current index of initial table
3201 >        int baseLimit;          // index bound for initial table
3202 >        final int baseSize;     // initial table size
3203 >
3204 >        Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3205 >            this.tab = tab;
3206 >            this.baseSize = size;
3207 >            this.baseIndex = this.index = index;
3208 >            this.baseLimit = limit;
3209 >            this.next = null;
3210 >        }
3211 >
3212 >        /**
3213 >         * Advances if possible, returning next valid node, or null if none.
3214 >         */
3215 >        final Node<K,V> advance() {
3216 >            Node<K,V> e;
3217 >            if ((e = next) != null)
3218 >                e = e.next;
3219 >            for (;;) {
3220 >                Node<K,V>[] t; int i, n;  // must use locals in checks
3221 >                if (e != null)
3222 >                    return next = e;
3223 >                if (baseIndex >= baseLimit || (t = tab) == null ||
3224 >                    (n = t.length) <= (i = index) || i < 0)
3225 >                    return next = null;
3226 >                if ((e = tabAt(t, i)) != null && e.hash < 0) {
3227 >                    if (e instanceof ForwardingNode) {
3228 >                        tab = ((ForwardingNode<K,V>)e).nextTable;
3229 >                        e = null;
3230 >                        pushState(t, i, n);
3231 >                        continue;
3232 >                    }
3233 >                    else if (e instanceof TreeBin)
3234 >                        e = ((TreeBin<K,V>)e).first;
3235 >                    else
3236 >                        e = null;
3237 >                }
3238 >                if (stack != null)
3239 >                    recoverState(n);
3240 >                else if ((index = i + baseSize) >= n)
3241 >                    index = ++baseIndex; // visit upper slots if present
3242 >            }
3243 >        }
3244 >
3245 >        /**
3246 >         * Saves traversal state upon encountering a forwarding node.
3247 >         */
3248 >        private void pushState(Node<K,V>[] t, int i, int n) {
3249 >            TableStack<K,V> s = spare;  // reuse if possible
3250 >            if (s != null)
3251 >                spare = s.next;
3252 >            else
3253 >                s = new TableStack<K,V>();
3254 >            s.tab = t;
3255 >            s.length = n;
3256 >            s.index = i;
3257 >            s.next = stack;
3258 >            stack = s;
3259 >        }
3260 >
3261 >        /**
3262 >         * Possibly pops traversal state.
3263 >         *
3264 >         * @param n length of current table
3265 >         */
3266 >        private void recoverState(int n) {
3267 >            TableStack<K,V> s; int len;
3268 >            while ((s = stack) != null && (index += (len = s.length)) >= n) {
3269 >                n = len;
3270 >                index = s.index;
3271 >                tab = s.tab;
3272 >                s.tab = null;
3273 >                TableStack<K,V> next = s.next;
3274 >                s.next = spare; // save for reuse
3275 >                stack = next;
3276 >                spare = s;
3277 >            }
3278 >            if (s == null && (index += baseSize) >= n)
3279 >                index = ++baseIndex;
3280 >        }
3281 >    }
3282 >
3283 >    /**
3284 >     * Base of key, value, and entry Iterators. Adds fields to
3285 >     * Traverser to support iterator.remove.
3286 >     */
3287 >    static class BaseIterator<K,V> extends Traverser<K,V> {
3288 >        final ConcurrentHashMapV8<K,V> map;
3289 >        Node<K,V> lastReturned;
3290 >        BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3291 >                    ConcurrentHashMapV8<K,V> map) {
3292 >            super(tab, size, index, limit);
3293              this.map = map;
3294 +            advance();
3295          }
3296  
3297 +        public final boolean hasNext() { return next != null; }
3298 +        public final boolean hasMoreElements() { return next != null; }
3299 +
3300          public final void remove() {
3301 <            if (last == null)
3301 >            Node<K,V> p;
3302 >            if ((p = lastReturned) == null)
3303                  throw new IllegalStateException();
3304 <            map.remove(last.key);
3305 <            last = null;
3304 >            lastReturned = null;
3305 >            map.replaceNode(p.key, null, null);
3306          }
1950
1951        public final boolean hasNext()         { return next != null; }
1952        public final boolean hasMoreElements() { return next != null; }
3307      }
3308  
3309 <    static final class KeyIterator<K,V> extends ViewIterator<K,V>
3309 >    static final class KeyIterator<K,V> extends BaseIterator<K,V>
3310          implements Iterator<K>, Enumeration<K> {
3311 <        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3311 >        KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3312 >                    ConcurrentHashMapV8<K,V> map) {
3313 >            super(tab, index, size, limit, map);
3314 >        }
3315  
1959        @SuppressWarnings("unchecked")
3316          public final K next() {
3317 <            if (next == null)
3317 >            Node<K,V> p;
3318 >            if ((p = next) == null)
3319                  throw new NoSuchElementException();
3320 <            Object k = nextKey;
3320 >            K k = p.key;
3321 >            lastReturned = p;
3322              advance();
3323 <            return (K)k;
3323 >            return k;
3324          }
3325  
3326          public final K nextElement() { return next(); }
3327      }
3328  
3329 <    static final class ValueIterator<K,V> extends ViewIterator<K,V>
3329 >    static final class ValueIterator<K,V> extends BaseIterator<K,V>
3330          implements Iterator<V>, Enumeration<V> {
3331 <        ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3331 >        ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3332 >                      ConcurrentHashMapV8<K,V> map) {
3333 >            super(tab, index, size, limit, map);
3334 >        }
3335  
1975        @SuppressWarnings("unchecked")
3336          public final V next() {
3337 <            if (next == null)
3337 >            Node<K,V> p;
3338 >            if ((p = next) == null)
3339                  throw new NoSuchElementException();
3340 <            Object v = nextVal;
3340 >            V v = p.val;
3341 >            lastReturned = p;
3342              advance();
3343 <            return (V)v;
3343 >            return v;
3344          }
3345  
3346          public final V nextElement() { return next(); }
3347      }
3348  
3349 <    static final class EntryIterator<K,V> extends ViewIterator<K,V>
3349 >    static final class EntryIterator<K,V> extends BaseIterator<K,V>
3350          implements Iterator<Map.Entry<K,V>> {
3351 <        EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3352 <
3353 <        @SuppressWarnings("unchecked")
1992 <        public final Map.Entry<K,V> next() {
1993 <            if (next == null)
1994 <                throw new NoSuchElementException();
1995 <            Object k = nextKey;
1996 <            Object v = nextVal;
1997 <            advance();
1998 <            return new WriteThroughEntry<K,V>((K)k, (V)v, map);
3351 >        EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3352 >                      ConcurrentHashMapV8<K,V> map) {
3353 >            super(tab, index, size, limit, map);
3354          }
2000    }
3355  
2002    static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V>
2003        implements Iterator<Map.Entry<K,V>> {
2004        SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2005
2006        @SuppressWarnings("unchecked")
3356          public final Map.Entry<K,V> next() {
3357 <            if (next == null)
3357 >            Node<K,V> p;
3358 >            if ((p = next) == null)
3359                  throw new NoSuchElementException();
3360 <            Object k = nextKey;
3361 <            Object v = nextVal;
3360 >            K k = p.key;
3361 >            V v = p.val;
3362 >            lastReturned = p;
3363              advance();
3364 <            return new SnapshotEntry<K,V>((K)k, (V)v);
3364 >            return new MapEntry<K,V>(k, v, map);
3365          }
3366      }
3367  
3368      /**
3369 <     * Base of writeThrough and Snapshot entry classes
3369 >     * Exported Entry for EntryIterator
3370       */
3371 <    static abstract class MapEntry<K,V> implements Map.Entry<K, V> {
3371 >    static final class MapEntry<K,V> implements Map.Entry<K,V> {
3372          final K key; // non-null
3373          V val;       // non-null
3374 <        MapEntry(K key, V val)        { this.key = key; this.val = val; }
3375 <        public final K getKey()       { return key; }
3376 <        public final V getValue()     { return val; }
3377 <        public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3378 <        public final String toString(){ return key + "=" + val; }
3374 >        final ConcurrentHashMapV8<K,V> map;
3375 >        MapEntry(K key, V val, ConcurrentHashMapV8<K,V> map) {
3376 >            this.key = key;
3377 >            this.val = val;
3378 >            this.map = map;
3379 >        }
3380 >        public K getKey()        { return key; }
3381 >        public V getValue()      { return val; }
3382 >        public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3383 >        public String toString() { return key + "=" + val; }
3384  
3385 <        public final boolean equals(Object o) {
3385 >        public boolean equals(Object o) {
3386              Object k, v; Map.Entry<?,?> e;
3387              return ((o instanceof Map.Entry) &&
3388                      (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
# Line 2035 | Line 3391 | public class ConcurrentHashMapV8<K, V>
3391                      (v == val || v.equals(val)));
3392          }
3393  
2038        public abstract V setValue(V value);
2039    }
2040
2041    /**
2042     * Entry used by EntryIterator.next(), that relays setValue
2043     * changes to the underlying map.
2044     */
2045    static final class WriteThroughEntry<K,V> extends MapEntry<K,V>
2046        implements Map.Entry<K, V> {
2047        final ConcurrentHashMapV8<K, V> map;
2048        WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2049            super(key, val);
2050            this.map = map;
2051        }
2052
3394          /**
3395           * Sets our entry's value and writes through to the map. The
3396 <         * value to return is somewhat arbitrary here. Since a
3397 <         * WriteThroughEntry does not necessarily track asynchronous
3398 <         * changes, the most recent "previous" value could be
3399 <         * different from what we return (or could even have been
3400 <         * removed in which case the put will re-establish). We do not
2060 <         * and cannot guarantee more.
3396 >         * value to return is somewhat arbitrary here. Since we do not
3397 >         * necessarily track asynchronous changes, the most recent
3398 >         * "previous" value could be different from what we return (or
3399 >         * could even have been removed, in which case the put will
3400 >         * re-establish). We do not and cannot guarantee more.
3401           */
3402 <        public final V setValue(V value) {
3402 >        public V setValue(V value) {
3403              if (value == null) throw new NullPointerException();
3404              V v = val;
3405              val = value;
# Line 2068 | Line 3408 | public class ConcurrentHashMapV8<K, V>
3408          }
3409      }
3410  
3411 +    static final class KeySpliterator<K,V> extends Traverser<K,V>
3412 +        implements ConcurrentHashMapSpliterator<K> {
3413 +        long est;               // size estimate
3414 +        KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3415 +                       long est) {
3416 +            super(tab, size, index, limit);
3417 +            this.est = est;
3418 +        }
3419 +
3420 +        public ConcurrentHashMapSpliterator<K> trySplit() {
3421 +            int i, f, h;
3422 +            return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3423 +                new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3424 +                                        f, est >>>= 1);
3425 +        }
3426 +
3427 +        public void forEachRemaining(Action<? super K> action) {
3428 +            if (action == null) throw new NullPointerException();
3429 +            for (Node<K,V> p; (p = advance()) != null;)
3430 +                action.apply(p.key);
3431 +        }
3432 +
3433 +        public boolean tryAdvance(Action<? super K> action) {
3434 +            if (action == null) throw new NullPointerException();
3435 +            Node<K,V> p;
3436 +            if ((p = advance()) == null)
3437 +                return false;
3438 +            action.apply(p.key);
3439 +            return true;
3440 +        }
3441 +
3442 +        public long estimateSize() { return est; }
3443 +
3444 +    }
3445 +
3446 +    static final class ValueSpliterator<K,V> extends Traverser<K,V>
3447 +        implements ConcurrentHashMapSpliterator<V> {
3448 +        long est;               // size estimate
3449 +        ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3450 +                         long est) {
3451 +            super(tab, size, index, limit);
3452 +            this.est = est;
3453 +        }
3454 +
3455 +        public ConcurrentHashMapSpliterator<V> trySplit() {
3456 +            int i, f, h;
3457 +            return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3458 +                new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3459 +                                          f, est >>>= 1);
3460 +        }
3461 +
3462 +        public void forEachRemaining(Action<? super V> action) {
3463 +            if (action == null) throw new NullPointerException();
3464 +            for (Node<K,V> p; (p = advance()) != null;)
3465 +                action.apply(p.val);
3466 +        }
3467 +
3468 +        public boolean tryAdvance(Action<? super V> action) {
3469 +            if (action == null) throw new NullPointerException();
3470 +            Node<K,V> p;
3471 +            if ((p = advance()) == null)
3472 +                return false;
3473 +            action.apply(p.val);
3474 +            return true;
3475 +        }
3476 +
3477 +        public long estimateSize() { return est; }
3478 +
3479 +    }
3480 +
3481 +    static final class EntrySpliterator<K,V> extends Traverser<K,V>
3482 +        implements ConcurrentHashMapSpliterator<Map.Entry<K,V>> {
3483 +        final ConcurrentHashMapV8<K,V> map; // To export MapEntry
3484 +        long est;               // size estimate
3485 +        EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3486 +                         long est, ConcurrentHashMapV8<K,V> map) {
3487 +            super(tab, size, index, limit);
3488 +            this.map = map;
3489 +            this.est = est;
3490 +        }
3491 +
3492 +        public ConcurrentHashMapSpliterator<Map.Entry<K,V>> trySplit() {
3493 +            int i, f, h;
3494 +            return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3495 +                new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3496 +                                          f, est >>>= 1, map);
3497 +        }
3498 +
3499 +        public void forEachRemaining(Action<? super Map.Entry<K,V>> action) {
3500 +            if (action == null) throw new NullPointerException();
3501 +            for (Node<K,V> p; (p = advance()) != null; )
3502 +                action.apply(new MapEntry<K,V>(p.key, p.val, map));
3503 +        }
3504 +
3505 +        public boolean tryAdvance(Action<? super Map.Entry<K,V>> action) {
3506 +            if (action == null) throw new NullPointerException();
3507 +            Node<K,V> p;
3508 +            if ((p = advance()) == null)
3509 +                return false;
3510 +            action.apply(new MapEntry<K,V>(p.key, p.val, map));
3511 +            return true;
3512 +        }
3513 +
3514 +        public long estimateSize() { return est; }
3515 +
3516 +    }
3517 +
3518 +    // Parallel bulk operations
3519 +
3520      /**
3521 <     * Internal version of entry, that doesn't write though changes
3521 >     * Computes initial batch value for bulk tasks. The returned value
3522 >     * is approximately exp2 of the number of times (minus one) to
3523 >     * split task by two before executing leaf action. This value is
3524 >     * faster to compute and more convenient to use as a guide to
3525 >     * splitting than is the depth, since it is used while dividing by
3526 >     * two anyway.
3527       */
3528 <    static final class SnapshotEntry<K,V> extends MapEntry<K,V>
3529 <        implements Map.Entry<K, V> {
3530 <        SnapshotEntry(K key, V val) { super(key, val); }
3531 <        public final V setValue(V value) { // only locally update
3532 <            if (value == null) throw new NullPointerException();
3533 <            V v = val;
3534 <            val = value;
3535 <            return v;
3536 <        }
3528 >    final int batchFor(long b) {
3529 >        long n;
3530 >        if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3531 >            return 0;
3532 >        int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3533 >        return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3534 >    }
3535 >
3536 >    /**
3537 >     * Performs the given action for each (key, value).
3538 >     *
3539 >     * @param parallelismThreshold the (estimated) number of elements
3540 >     * needed for this operation to be executed in parallel
3541 >     * @param action the action
3542 >     * @since 1.8
3543 >     */
3544 >    public void forEach(long parallelismThreshold,
3545 >                        BiAction<? super K,? super V> action) {
3546 >        if (action == null) throw new NullPointerException();
3547 >        new ForEachMappingTask<K,V>
3548 >            (null, batchFor(parallelismThreshold), 0, 0, table,
3549 >             action).invoke();
3550 >    }
3551 >
3552 >    /**
3553 >     * Performs the given action for each non-null transformation
3554 >     * of each (key, value).
3555 >     *
3556 >     * @param parallelismThreshold the (estimated) number of elements
3557 >     * needed for this operation to be executed in parallel
3558 >     * @param transformer a function returning the transformation
3559 >     * for an element, or null if there is no transformation (in
3560 >     * which case the action is not applied)
3561 >     * @param action the action
3562 >     * @since 1.8
3563 >     */
3564 >    public <U> void forEach(long parallelismThreshold,
3565 >                            BiFun<? super K, ? super V, ? extends U> transformer,
3566 >                            Action<? super U> action) {
3567 >        if (transformer == null || action == null)
3568 >            throw new NullPointerException();
3569 >        new ForEachTransformedMappingTask<K,V,U>
3570 >            (null, batchFor(parallelismThreshold), 0, 0, table,
3571 >             transformer, action).invoke();
3572 >    }
3573 >
3574 >    /**
3575 >     * Returns a non-null result from applying the given search
3576 >     * function on each (key, value), or null if none.  Upon
3577 >     * success, further element processing is suppressed and the
3578 >     * results of any other parallel invocations of the search
3579 >     * function are ignored.
3580 >     *
3581 >     * @param parallelismThreshold the (estimated) number of elements
3582 >     * needed for this operation to be executed in parallel
3583 >     * @param searchFunction a function returning a non-null
3584 >     * result on success, else null
3585 >     * @return a non-null result from applying the given search
3586 >     * function on each (key, value), or null if none
3587 >     * @since 1.8
3588 >     */
3589 >    public <U> U search(long parallelismThreshold,
3590 >                        BiFun<? super K, ? super V, ? extends U> searchFunction) {
3591 >        if (searchFunction == null) throw new NullPointerException();
3592 >        return new SearchMappingsTask<K,V,U>
3593 >            (null, batchFor(parallelismThreshold), 0, 0, table,
3594 >             searchFunction, new AtomicReference<U>()).invoke();
3595 >    }
3596 >
3597 >    /**
3598 >     * Returns the result of accumulating the given transformation
3599 >     * of all (key, value) pairs using the given reducer to
3600 >     * combine values, or null if none.
3601 >     *
3602 >     * @param parallelismThreshold the (estimated) number of elements
3603 >     * needed for this operation to be executed in parallel
3604 >     * @param transformer a function returning the transformation
3605 >     * for an element, or null if there is no transformation (in
3606 >     * which case it is not combined)
3607 >     * @param reducer a commutative associative combining function
3608 >     * @return the result of accumulating the given transformation
3609 >     * of all (key, value) pairs
3610 >     * @since 1.8
3611 >     */
3612 >    public <U> U reduce(long parallelismThreshold,
3613 >                        BiFun<? super K, ? super V, ? extends U> transformer,
3614 >                        BiFun<? super U, ? super U, ? extends U> reducer) {
3615 >        if (transformer == null || reducer == null)
3616 >            throw new NullPointerException();
3617 >        return new MapReduceMappingsTask<K,V,U>
3618 >            (null, batchFor(parallelismThreshold), 0, 0, table,
3619 >             null, transformer, reducer).invoke();
3620 >    }
3621 >
3622 >    /**
3623 >     * Returns the result of accumulating the given transformation
3624 >     * of all (key, value) pairs using the given reducer to
3625 >     * combine values, and the given basis as an identity value.
3626 >     *
3627 >     * @param parallelismThreshold the (estimated) number of elements
3628 >     * needed for this operation to be executed in parallel
3629 >     * @param transformer a function returning the transformation
3630 >     * for an element
3631 >     * @param basis the identity (initial default value) for the reduction
3632 >     * @param reducer a commutative associative combining function
3633 >     * @return the result of accumulating the given transformation
3634 >     * of all (key, value) pairs
3635 >     * @since 1.8
3636 >     */
3637 >    public double reduceToDouble(long parallelismThreshold,
3638 >                                 ObjectByObjectToDouble<? super K, ? super V> transformer,
3639 >                                 double basis,
3640 >                                 DoubleByDoubleToDouble reducer) {
3641 >        if (transformer == null || reducer == null)
3642 >            throw new NullPointerException();
3643 >        return new MapReduceMappingsToDoubleTask<K,V>
3644 >            (null, batchFor(parallelismThreshold), 0, 0, table,
3645 >             null, transformer, basis, reducer).invoke();
3646      }
3647  
3648 +    /**
3649 +     * Returns the result of accumulating the given transformation
3650 +     * of all (key, value) pairs using the given reducer to
3651 +     * combine values, and the given basis as an identity value.
3652 +     *
3653 +     * @param parallelismThreshold the (estimated) number of elements
3654 +     * needed for this operation to be executed in parallel
3655 +     * @param transformer a function returning the transformation
3656 +     * for an element
3657 +     * @param basis the identity (initial default value) for the reduction
3658 +     * @param reducer a commutative associative combining function
3659 +     * @return the result of accumulating the given transformation
3660 +     * of all (key, value) pairs
3661 +     * @since 1.8
3662 +     */
3663 +    public long reduceToLong(long parallelismThreshold,
3664 +                             ObjectByObjectToLong<? super K, ? super V> transformer,
3665 +                             long basis,
3666 +                             LongByLongToLong reducer) {
3667 +        if (transformer == null || reducer == null)
3668 +            throw new NullPointerException();
3669 +        return new MapReduceMappingsToLongTask<K,V>
3670 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3671 +             null, transformer, basis, reducer).invoke();
3672 +    }
3673 +
3674 +    /**
3675 +     * Returns the result of accumulating the given transformation
3676 +     * of all (key, value) pairs using the given reducer to
3677 +     * combine values, and the given basis as an identity value.
3678 +     *
3679 +     * @param parallelismThreshold the (estimated) number of elements
3680 +     * needed for this operation to be executed in parallel
3681 +     * @param transformer a function returning the transformation
3682 +     * for an element
3683 +     * @param basis the identity (initial default value) for the reduction
3684 +     * @param reducer a commutative associative combining function
3685 +     * @return the result of accumulating the given transformation
3686 +     * of all (key, value) pairs
3687 +     * @since 1.8
3688 +     */
3689 +    public int reduceToInt(long parallelismThreshold,
3690 +                           ObjectByObjectToInt<? super K, ? super V> transformer,
3691 +                           int basis,
3692 +                           IntByIntToInt reducer) {
3693 +        if (transformer == null || reducer == null)
3694 +            throw new NullPointerException();
3695 +        return new MapReduceMappingsToIntTask<K,V>
3696 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3697 +             null, transformer, basis, reducer).invoke();
3698 +    }
3699 +
3700 +    /**
3701 +     * Performs the given action for each key.
3702 +     *
3703 +     * @param parallelismThreshold the (estimated) number of elements
3704 +     * needed for this operation to be executed in parallel
3705 +     * @param action the action
3706 +     * @since 1.8
3707 +     */
3708 +    public void forEachKey(long parallelismThreshold,
3709 +                           Action<? super K> action) {
3710 +        if (action == null) throw new NullPointerException();
3711 +        new ForEachKeyTask<K,V>
3712 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3713 +             action).invoke();
3714 +    }
3715 +
3716 +    /**
3717 +     * Performs the given action for each non-null transformation
3718 +     * of each key.
3719 +     *
3720 +     * @param parallelismThreshold the (estimated) number of elements
3721 +     * needed for this operation to be executed in parallel
3722 +     * @param transformer a function returning the transformation
3723 +     * for an element, or null if there is no transformation (in
3724 +     * which case the action is not applied)
3725 +     * @param action the action
3726 +     * @since 1.8
3727 +     */
3728 +    public <U> void forEachKey(long parallelismThreshold,
3729 +                               Fun<? super K, ? extends U> transformer,
3730 +                               Action<? super U> action) {
3731 +        if (transformer == null || action == null)
3732 +            throw new NullPointerException();
3733 +        new ForEachTransformedKeyTask<K,V,U>
3734 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3735 +             transformer, action).invoke();
3736 +    }
3737 +
3738 +    /**
3739 +     * Returns a non-null result from applying the given search
3740 +     * function on each key, or null if none. Upon success,
3741 +     * further element processing is suppressed and the results of
3742 +     * any other parallel invocations of the search function are
3743 +     * ignored.
3744 +     *
3745 +     * @param parallelismThreshold the (estimated) number of elements
3746 +     * needed for this operation to be executed in parallel
3747 +     * @param searchFunction a function returning a non-null
3748 +     * result on success, else null
3749 +     * @return a non-null result from applying the given search
3750 +     * function on each key, or null if none
3751 +     * @since 1.8
3752 +     */
3753 +    public <U> U searchKeys(long parallelismThreshold,
3754 +                            Fun<? super K, ? extends U> searchFunction) {
3755 +        if (searchFunction == null) throw new NullPointerException();
3756 +        return new SearchKeysTask<K,V,U>
3757 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3758 +             searchFunction, new AtomicReference<U>()).invoke();
3759 +    }
3760 +
3761 +    /**
3762 +     * Returns the result of accumulating all keys using the given
3763 +     * reducer to combine values, or null if none.
3764 +     *
3765 +     * @param parallelismThreshold the (estimated) number of elements
3766 +     * needed for this operation to be executed in parallel
3767 +     * @param reducer a commutative associative combining function
3768 +     * @return the result of accumulating all keys using the given
3769 +     * reducer to combine values, or null if none
3770 +     * @since 1.8
3771 +     */
3772 +    public K reduceKeys(long parallelismThreshold,
3773 +                        BiFun<? super K, ? super K, ? extends K> reducer) {
3774 +        if (reducer == null) throw new NullPointerException();
3775 +        return new ReduceKeysTask<K,V>
3776 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3777 +             null, reducer).invoke();
3778 +    }
3779 +
3780 +    /**
3781 +     * Returns the result of accumulating the given transformation
3782 +     * of all keys using the given reducer to combine values, or
3783 +     * null if none.
3784 +     *
3785 +     * @param parallelismThreshold the (estimated) number of elements
3786 +     * needed for this operation to be executed in parallel
3787 +     * @param transformer a function returning the transformation
3788 +     * for an element, or null if there is no transformation (in
3789 +     * which case it is not combined)
3790 +     * @param reducer a commutative associative combining function
3791 +     * @return the result of accumulating the given transformation
3792 +     * of all keys
3793 +     * @since 1.8
3794 +     */
3795 +    public <U> U reduceKeys(long parallelismThreshold,
3796 +                            Fun<? super K, ? extends U> transformer,
3797 +         BiFun<? super U, ? super U, ? extends U> reducer) {
3798 +        if (transformer == null || reducer == null)
3799 +            throw new NullPointerException();
3800 +        return new MapReduceKeysTask<K,V,U>
3801 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3802 +             null, transformer, reducer).invoke();
3803 +    }
3804 +
3805 +    /**
3806 +     * Returns the result of accumulating the given transformation
3807 +     * of all keys using the given reducer to combine values, and
3808 +     * the given basis as an identity value.
3809 +     *
3810 +     * @param parallelismThreshold the (estimated) number of elements
3811 +     * needed for this operation to be executed in parallel
3812 +     * @param transformer a function returning the transformation
3813 +     * for an element
3814 +     * @param basis the identity (initial default value) for the reduction
3815 +     * @param reducer a commutative associative combining function
3816 +     * @return the result of accumulating the given transformation
3817 +     * of all keys
3818 +     * @since 1.8
3819 +     */
3820 +    public double reduceKeysToDouble(long parallelismThreshold,
3821 +                                     ObjectToDouble<? super K> transformer,
3822 +                                     double basis,
3823 +                                     DoubleByDoubleToDouble reducer) {
3824 +        if (transformer == null || reducer == null)
3825 +            throw new NullPointerException();
3826 +        return new MapReduceKeysToDoubleTask<K,V>
3827 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3828 +             null, transformer, basis, reducer).invoke();
3829 +    }
3830 +
3831 +    /**
3832 +     * Returns the result of accumulating the given transformation
3833 +     * of all keys using the given reducer to combine values, and
3834 +     * the given basis as an identity value.
3835 +     *
3836 +     * @param parallelismThreshold the (estimated) number of elements
3837 +     * needed for this operation to be executed in parallel
3838 +     * @param transformer a function returning the transformation
3839 +     * for an element
3840 +     * @param basis the identity (initial default value) for the reduction
3841 +     * @param reducer a commutative associative combining function
3842 +     * @return the result of accumulating the given transformation
3843 +     * of all keys
3844 +     * @since 1.8
3845 +     */
3846 +    public long reduceKeysToLong(long parallelismThreshold,
3847 +                                 ObjectToLong<? super K> transformer,
3848 +                                 long basis,
3849 +                                 LongByLongToLong reducer) {
3850 +        if (transformer == null || reducer == null)
3851 +            throw new NullPointerException();
3852 +        return new MapReduceKeysToLongTask<K,V>
3853 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3854 +             null, transformer, basis, reducer).invoke();
3855 +    }
3856 +
3857 +    /**
3858 +     * Returns the result of accumulating the given transformation
3859 +     * of all keys using the given reducer to combine values, and
3860 +     * the given basis as an identity value.
3861 +     *
3862 +     * @param parallelismThreshold the (estimated) number of elements
3863 +     * needed for this operation to be executed in parallel
3864 +     * @param transformer a function returning the transformation
3865 +     * for an element
3866 +     * @param basis the identity (initial default value) for the reduction
3867 +     * @param reducer a commutative associative combining function
3868 +     * @return the result of accumulating the given transformation
3869 +     * of all keys
3870 +     * @since 1.8
3871 +     */
3872 +    public int reduceKeysToInt(long parallelismThreshold,
3873 +                               ObjectToInt<? super K> transformer,
3874 +                               int basis,
3875 +                               IntByIntToInt reducer) {
3876 +        if (transformer == null || reducer == null)
3877 +            throw new NullPointerException();
3878 +        return new MapReduceKeysToIntTask<K,V>
3879 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3880 +             null, transformer, basis, reducer).invoke();
3881 +    }
3882 +
3883 +    /**
3884 +     * Performs the given action for each value.
3885 +     *
3886 +     * @param parallelismThreshold the (estimated) number of elements
3887 +     * needed for this operation to be executed in parallel
3888 +     * @param action the action
3889 +     * @since 1.8
3890 +     */
3891 +    public void forEachValue(long parallelismThreshold,
3892 +                             Action<? super V> action) {
3893 +        if (action == null)
3894 +            throw new NullPointerException();
3895 +        new ForEachValueTask<K,V>
3896 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3897 +             action).invoke();
3898 +    }
3899 +
3900 +    /**
3901 +     * Performs the given action for each non-null transformation
3902 +     * of each 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, or null if there is no transformation (in
3908 +     * which case the action is not applied)
3909 +     * @param action the action
3910 +     * @since 1.8
3911 +     */
3912 +    public <U> void forEachValue(long parallelismThreshold,
3913 +                                 Fun<? super V, ? extends U> transformer,
3914 +                                 Action<? super U> action) {
3915 +        if (transformer == null || action == null)
3916 +            throw new NullPointerException();
3917 +        new ForEachTransformedValueTask<K,V,U>
3918 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3919 +             transformer, action).invoke();
3920 +    }
3921 +
3922 +    /**
3923 +     * Returns a non-null result from applying the given search
3924 +     * function on each value, or null if none.  Upon success,
3925 +     * further element processing is suppressed and the results of
3926 +     * any other parallel invocations of the search function are
3927 +     * ignored.
3928 +     *
3929 +     * @param parallelismThreshold the (estimated) number of elements
3930 +     * needed for this operation to be executed in parallel
3931 +     * @param searchFunction a function returning a non-null
3932 +     * result on success, else null
3933 +     * @return a non-null result from applying the given search
3934 +     * function on each value, or null if none
3935 +     * @since 1.8
3936 +     */
3937 +    public <U> U searchValues(long parallelismThreshold,
3938 +                              Fun<? super V, ? extends U> searchFunction) {
3939 +        if (searchFunction == null) throw new NullPointerException();
3940 +        return new SearchValuesTask<K,V,U>
3941 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3942 +             searchFunction, new AtomicReference<U>()).invoke();
3943 +    }
3944 +
3945 +    /**
3946 +     * Returns the result of accumulating all values using the
3947 +     * given reducer to combine values, or null if none.
3948 +     *
3949 +     * @param parallelismThreshold the (estimated) number of elements
3950 +     * needed for this operation to be executed in parallel
3951 +     * @param reducer a commutative associative combining function
3952 +     * @return the result of accumulating all values
3953 +     * @since 1.8
3954 +     */
3955 +    public V reduceValues(long parallelismThreshold,
3956 +                          BiFun<? super V, ? super V, ? extends V> reducer) {
3957 +        if (reducer == null) throw new NullPointerException();
3958 +        return new ReduceValuesTask<K,V>
3959 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3960 +             null, reducer).invoke();
3961 +    }
3962 +
3963 +    /**
3964 +     * Returns the result of accumulating the given transformation
3965 +     * of all values using the given reducer to combine values, or
3966 +     * null if none.
3967 +     *
3968 +     * @param parallelismThreshold the (estimated) number of elements
3969 +     * needed for this operation to be executed in parallel
3970 +     * @param transformer a function returning the transformation
3971 +     * for an element, or null if there is no transformation (in
3972 +     * which case it is not combined)
3973 +     * @param reducer a commutative associative combining function
3974 +     * @return the result of accumulating the given transformation
3975 +     * of all values
3976 +     * @since 1.8
3977 +     */
3978 +    public <U> U reduceValues(long parallelismThreshold,
3979 +                              Fun<? super V, ? extends U> transformer,
3980 +                              BiFun<? super U, ? super U, ? extends U> reducer) {
3981 +        if (transformer == null || reducer == null)
3982 +            throw new NullPointerException();
3983 +        return new MapReduceValuesTask<K,V,U>
3984 +            (null, batchFor(parallelismThreshold), 0, 0, table,
3985 +             null, transformer, reducer).invoke();
3986 +    }
3987 +
3988 +    /**
3989 +     * Returns the result of accumulating the given transformation
3990 +     * of all values using the given reducer to combine values,
3991 +     * and the given basis as an identity value.
3992 +     *
3993 +     * @param parallelismThreshold the (estimated) number of elements
3994 +     * needed for this operation to be executed in parallel
3995 +     * @param transformer a function returning the transformation
3996 +     * for an element
3997 +     * @param basis the identity (initial default value) for the reduction
3998 +     * @param reducer a commutative associative combining function
3999 +     * @return the result of accumulating the given transformation
4000 +     * of all values
4001 +     * @since 1.8
4002 +     */
4003 +    public double reduceValuesToDouble(long parallelismThreshold,
4004 +                                       ObjectToDouble<? super V> transformer,
4005 +                                       double basis,
4006 +                                       DoubleByDoubleToDouble reducer) {
4007 +        if (transformer == null || reducer == null)
4008 +            throw new NullPointerException();
4009 +        return new MapReduceValuesToDoubleTask<K,V>
4010 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4011 +             null, transformer, basis, reducer).invoke();
4012 +    }
4013 +
4014 +    /**
4015 +     * Returns the result of accumulating the given transformation
4016 +     * of all values using the given reducer to combine values,
4017 +     * and the given basis as an identity value.
4018 +     *
4019 +     * @param parallelismThreshold the (estimated) number of elements
4020 +     * needed for this operation to be executed in parallel
4021 +     * @param transformer a function returning the transformation
4022 +     * for an element
4023 +     * @param basis the identity (initial default value) for the reduction
4024 +     * @param reducer a commutative associative combining function
4025 +     * @return the result of accumulating the given transformation
4026 +     * of all values
4027 +     * @since 1.8
4028 +     */
4029 +    public long reduceValuesToLong(long parallelismThreshold,
4030 +                                   ObjectToLong<? super V> transformer,
4031 +                                   long basis,
4032 +                                   LongByLongToLong reducer) {
4033 +        if (transformer == null || reducer == null)
4034 +            throw new NullPointerException();
4035 +        return new MapReduceValuesToLongTask<K,V>
4036 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4037 +             null, transformer, basis, reducer).invoke();
4038 +    }
4039 +
4040 +    /**
4041 +     * Returns the result of accumulating the given transformation
4042 +     * of all values using the given reducer to combine values,
4043 +     * and the given basis as an identity value.
4044 +     *
4045 +     * @param parallelismThreshold the (estimated) number of elements
4046 +     * needed for this operation to be executed in parallel
4047 +     * @param transformer a function returning the transformation
4048 +     * for an element
4049 +     * @param basis the identity (initial default value) for the reduction
4050 +     * @param reducer a commutative associative combining function
4051 +     * @return the result of accumulating the given transformation
4052 +     * of all values
4053 +     * @since 1.8
4054 +     */
4055 +    public int reduceValuesToInt(long parallelismThreshold,
4056 +                                 ObjectToInt<? super V> transformer,
4057 +                                 int basis,
4058 +                                 IntByIntToInt reducer) {
4059 +        if (transformer == null || reducer == null)
4060 +            throw new NullPointerException();
4061 +        return new MapReduceValuesToIntTask<K,V>
4062 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4063 +             null, transformer, basis, reducer).invoke();
4064 +    }
4065 +
4066 +    /**
4067 +     * Performs the given action for each entry.
4068 +     *
4069 +     * @param parallelismThreshold the (estimated) number of elements
4070 +     * needed for this operation to be executed in parallel
4071 +     * @param action the action
4072 +     * @since 1.8
4073 +     */
4074 +    public void forEachEntry(long parallelismThreshold,
4075 +                             Action<? super Map.Entry<K,V>> action) {
4076 +        if (action == null) throw new NullPointerException();
4077 +        new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4078 +                                  action).invoke();
4079 +    }
4080 +
4081 +    /**
4082 +     * Performs the given action for each non-null transformation
4083 +     * of each entry.
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, or null if there is no transformation (in
4089 +     * which case the action is not applied)
4090 +     * @param action the action
4091 +     * @since 1.8
4092 +     */
4093 +    public <U> void forEachEntry(long parallelismThreshold,
4094 +                                 Fun<Map.Entry<K,V>, ? extends U> transformer,
4095 +                                 Action<? super U> action) {
4096 +        if (transformer == null || action == null)
4097 +            throw new NullPointerException();
4098 +        new ForEachTransformedEntryTask<K,V,U>
4099 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4100 +             transformer, action).invoke();
4101 +    }
4102 +
4103 +    /**
4104 +     * Returns a non-null result from applying the given search
4105 +     * function on each entry, or null if none.  Upon success,
4106 +     * further element processing is suppressed and the results of
4107 +     * any other parallel invocations of the search function are
4108 +     * ignored.
4109 +     *
4110 +     * @param parallelismThreshold the (estimated) number of elements
4111 +     * needed for this operation to be executed in parallel
4112 +     * @param searchFunction a function returning a non-null
4113 +     * result on success, else null
4114 +     * @return a non-null result from applying the given search
4115 +     * function on each entry, or null if none
4116 +     * @since 1.8
4117 +     */
4118 +    public <U> U searchEntries(long parallelismThreshold,
4119 +                               Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4120 +        if (searchFunction == null) throw new NullPointerException();
4121 +        return new SearchEntriesTask<K,V,U>
4122 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4123 +             searchFunction, new AtomicReference<U>()).invoke();
4124 +    }
4125 +
4126 +    /**
4127 +     * Returns the result of accumulating all entries using the
4128 +     * given reducer to combine values, or null if none.
4129 +     *
4130 +     * @param parallelismThreshold the (estimated) number of elements
4131 +     * needed for this operation to be executed in parallel
4132 +     * @param reducer a commutative associative combining function
4133 +     * @return the result of accumulating all entries
4134 +     * @since 1.8
4135 +     */
4136 +    public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4137 +                                        BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4138 +        if (reducer == null) throw new NullPointerException();
4139 +        return new ReduceEntriesTask<K,V>
4140 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4141 +             null, reducer).invoke();
4142 +    }
4143 +
4144 +    /**
4145 +     * Returns the result of accumulating the given transformation
4146 +     * of all entries using the given reducer to combine values,
4147 +     * or null if none.
4148 +     *
4149 +     * @param parallelismThreshold the (estimated) number of elements
4150 +     * needed for this operation to be executed in parallel
4151 +     * @param transformer a function returning the transformation
4152 +     * for an element, or null if there is no transformation (in
4153 +     * which case it is not combined)
4154 +     * @param reducer a commutative associative combining function
4155 +     * @return the result of accumulating the given transformation
4156 +     * of all entries
4157 +     * @since 1.8
4158 +     */
4159 +    public <U> U reduceEntries(long parallelismThreshold,
4160 +                               Fun<Map.Entry<K,V>, ? extends U> transformer,
4161 +                               BiFun<? super U, ? super U, ? extends U> reducer) {
4162 +        if (transformer == null || reducer == null)
4163 +            throw new NullPointerException();
4164 +        return new MapReduceEntriesTask<K,V,U>
4165 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4166 +             null, transformer, reducer).invoke();
4167 +    }
4168 +
4169 +    /**
4170 +     * Returns the result of accumulating the given transformation
4171 +     * of all entries using the given reducer to combine values,
4172 +     * and the given basis as an identity value.
4173 +     *
4174 +     * @param parallelismThreshold the (estimated) number of elements
4175 +     * needed for this operation to be executed in parallel
4176 +     * @param transformer a function returning the transformation
4177 +     * for an element
4178 +     * @param basis the identity (initial default value) for the reduction
4179 +     * @param reducer a commutative associative combining function
4180 +     * @return the result of accumulating the given transformation
4181 +     * of all entries
4182 +     * @since 1.8
4183 +     */
4184 +    public double reduceEntriesToDouble(long parallelismThreshold,
4185 +                                        ObjectToDouble<Map.Entry<K,V>> transformer,
4186 +                                        double basis,
4187 +                                        DoubleByDoubleToDouble reducer) {
4188 +        if (transformer == null || reducer == null)
4189 +            throw new NullPointerException();
4190 +        return new MapReduceEntriesToDoubleTask<K,V>
4191 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4192 +             null, transformer, basis, reducer).invoke();
4193 +    }
4194 +
4195 +    /**
4196 +     * Returns the result of accumulating the given transformation
4197 +     * of all entries using the given reducer to combine values,
4198 +     * and the given basis as an identity value.
4199 +     *
4200 +     * @param parallelismThreshold the (estimated) number of elements
4201 +     * needed for this operation to be executed in parallel
4202 +     * @param transformer a function returning the transformation
4203 +     * for an element
4204 +     * @param basis the identity (initial default value) for the reduction
4205 +     * @param reducer a commutative associative combining function
4206 +     * @return the result of accumulating the given transformation
4207 +     * of all entries
4208 +     * @since 1.8
4209 +     */
4210 +    public long reduceEntriesToLong(long parallelismThreshold,
4211 +                                    ObjectToLong<Map.Entry<K,V>> transformer,
4212 +                                    long basis,
4213 +                                    LongByLongToLong reducer) {
4214 +        if (transformer == null || reducer == null)
4215 +            throw new NullPointerException();
4216 +        return new MapReduceEntriesToLongTask<K,V>
4217 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4218 +             null, transformer, basis, reducer).invoke();
4219 +    }
4220 +
4221 +    /**
4222 +     * Returns the result of accumulating the given transformation
4223 +     * of all entries using the given reducer to combine values,
4224 +     * and the given basis as an identity value.
4225 +     *
4226 +     * @param parallelismThreshold the (estimated) number of elements
4227 +     * needed for this operation to be executed in parallel
4228 +     * @param transformer a function returning the transformation
4229 +     * for an element
4230 +     * @param basis the identity (initial default value) for the reduction
4231 +     * @param reducer a commutative associative combining function
4232 +     * @return the result of accumulating the given transformation
4233 +     * of all entries
4234 +     * @since 1.8
4235 +     */
4236 +    public int reduceEntriesToInt(long parallelismThreshold,
4237 +                                  ObjectToInt<Map.Entry<K,V>> transformer,
4238 +                                  int basis,
4239 +                                  IntByIntToInt reducer) {
4240 +        if (transformer == null || reducer == null)
4241 +            throw new NullPointerException();
4242 +        return new MapReduceEntriesToIntTask<K,V>
4243 +            (null, batchFor(parallelismThreshold), 0, 0, table,
4244 +             null, transformer, basis, reducer).invoke();
4245 +    }
4246 +
4247 +
4248      /* ----------------Views -------------- */
4249  
4250      /**
4251 <     * Base class for views. This is done mainly to allow adding
2089 <     * customized parallel traversals (not yet implemented.)
4251 >     * Base class for views.
4252       */
4253 <    static abstract class MapView<K, V> {
4254 <        final ConcurrentHashMapV8<K, V> map;
4255 <        MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
4256 <        public final int size()                 { return map.size(); }
4257 <        public final boolean isEmpty()          { return map.isEmpty(); }
4258 <        public final void clear()               { map.clear(); }
4253 >    abstract static class CollectionView<K,V,E>
4254 >        implements Collection<E>, java.io.Serializable {
4255 >        private static final long serialVersionUID = 7249069246763182397L;
4256 >        final ConcurrentHashMapV8<K,V> map;
4257 >        CollectionView(ConcurrentHashMapV8<K,V> map)  { this.map = map; }
4258 >
4259 >        /**
4260 >         * Returns the map backing this view.
4261 >         *
4262 >         * @return the map backing this view
4263 >         */
4264 >        public ConcurrentHashMapV8<K,V> getMap() { return map; }
4265 >
4266 >        /**
4267 >         * Removes all of the elements from this view, by removing all
4268 >         * the mappings from the map backing this view.
4269 >         */
4270 >        public final void clear()      { map.clear(); }
4271 >        public final int size()        { return map.size(); }
4272 >        public final boolean isEmpty() { return map.isEmpty(); }
4273  
4274          // implementations below rely on concrete classes supplying these
4275 <        abstract Iterator<?> iter();
4276 <        abstract public boolean contains(Object o);
4277 <        abstract public boolean remove(Object o);
4275 >        // abstract methods
4276 >        /**
4277 >         * Returns a "weakly consistent" iterator that will never
4278 >         * throw {@link ConcurrentModificationException}, and
4279 >         * guarantees to traverse elements as they existed upon
4280 >         * construction of the iterator, and may (but is not
4281 >         * guaranteed to) reflect any modifications subsequent to
4282 >         * construction.
4283 >         */
4284 >        public abstract Iterator<E> iterator();
4285 >        public abstract boolean contains(Object o);
4286 >        public abstract boolean remove(Object o);
4287  
4288          private static final String oomeMsg = "Required array size too large";
4289  
4290          public final Object[] toArray() {
4291 <            long sz = map.longSize();
4292 <            if (sz > (long)(MAX_ARRAY_SIZE))
4291 >            long sz = map.mappingCount();
4292 >            if (sz > MAX_ARRAY_SIZE)
4293                  throw new OutOfMemoryError(oomeMsg);
4294              int n = (int)sz;
4295              Object[] r = new Object[n];
4296              int i = 0;
4297 <            Iterator<?> it = iter();
2113 <            while (it.hasNext()) {
4297 >            for (E e : this) {
4298                  if (i == n) {
4299                      if (n >= MAX_ARRAY_SIZE)
4300                          throw new OutOfMemoryError(oomeMsg);
# Line 2120 | Line 4304 | public class ConcurrentHashMapV8<K, V>
4304                          n += (n >>> 1) + 1;
4305                      r = Arrays.copyOf(r, n);
4306                  }
4307 <                r[i++] = it.next();
4307 >                r[i++] = e;
4308              }
4309              return (i == n) ? r : Arrays.copyOf(r, i);
4310          }
4311  
4312          @SuppressWarnings("unchecked")
4313          public final <T> T[] toArray(T[] a) {
4314 <            long sz = map.longSize();
4315 <            if (sz > (long)(MAX_ARRAY_SIZE))
4314 >            long sz = map.mappingCount();
4315 >            if (sz > MAX_ARRAY_SIZE)
4316                  throw new OutOfMemoryError(oomeMsg);
4317              int m = (int)sz;
4318              T[] r = (a.length >= m) ? a :
# Line 2136 | Line 4320 | public class ConcurrentHashMapV8<K, V>
4320                  .newInstance(a.getClass().getComponentType(), m);
4321              int n = r.length;
4322              int i = 0;
4323 <            Iterator<?> it = iter();
2140 <            while (it.hasNext()) {
4323 >            for (E e : this) {
4324                  if (i == n) {
4325                      if (n >= MAX_ARRAY_SIZE)
4326                          throw new OutOfMemoryError(oomeMsg);
# Line 2147 | Line 4330 | public class ConcurrentHashMapV8<K, V>
4330                          n += (n >>> 1) + 1;
4331                      r = Arrays.copyOf(r, n);
4332                  }
4333 <                r[i++] = (T)it.next();
4333 >                r[i++] = (T)e;
4334              }
4335              if (a == r && i < n) {
4336                  r[i] = null; // null-terminate
# Line 2156 | Line 4339 | public class ConcurrentHashMapV8<K, V>
4339              return (i == n) ? r : Arrays.copyOf(r, i);
4340          }
4341  
4342 <        public final int hashCode() {
4343 <            int h = 0;
4344 <            for (Iterator<?> it = iter(); it.hasNext();)
4345 <                h += it.next().hashCode();
4346 <            return h;
4347 <        }
4348 <
4342 >        /**
4343 >         * Returns a string representation of this collection.
4344 >         * The string representation consists of the string representations
4345 >         * of the collection's elements in the order they are returned by
4346 >         * its iterator, enclosed in square brackets ({@code "[]"}).
4347 >         * Adjacent elements are separated by the characters {@code ", "}
4348 >         * (comma and space).  Elements are converted to strings as by
4349 >         * {@link String#valueOf(Object)}.
4350 >         *
4351 >         * @return a string representation of this collection
4352 >         */
4353          public final String toString() {
4354              StringBuilder sb = new StringBuilder();
4355              sb.append('[');
4356 <            Iterator<?> it = iter();
4356 >            Iterator<E> it = iterator();
4357              if (it.hasNext()) {
4358                  for (;;) {
4359                      Object e = it.next();
# Line 2181 | Line 4368 | public class ConcurrentHashMapV8<K, V>
4368  
4369          public final boolean containsAll(Collection<?> c) {
4370              if (c != this) {
4371 <                for (Iterator<?> it = c.iterator(); it.hasNext();) {
2185 <                    Object e = it.next();
4371 >                for (Object e : c) {
4372                      if (e == null || !contains(e))
4373                          return false;
4374                  }
# Line 2192 | Line 4378 | public class ConcurrentHashMapV8<K, V>
4378  
4379          public final boolean removeAll(Collection<?> c) {
4380              boolean modified = false;
4381 <            for (Iterator<?> it = iter(); it.hasNext();) {
4381 >            for (Iterator<E> it = iterator(); it.hasNext();) {
4382                  if (c.contains(it.next())) {
4383                      it.remove();
4384                      modified = true;
# Line 2203 | Line 4389 | public class ConcurrentHashMapV8<K, V>
4389  
4390          public final boolean retainAll(Collection<?> c) {
4391              boolean modified = false;
4392 <            for (Iterator<?> it = iter(); it.hasNext();) {
4392 >            for (Iterator<E> it = iterator(); it.hasNext();) {
4393                  if (!c.contains(it.next())) {
4394                      it.remove();
4395                      modified = true;
# Line 2214 | Line 4400 | public class ConcurrentHashMapV8<K, V>
4400  
4401      }
4402  
4403 <    static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
4404 <        KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
4405 <        public final boolean contains(Object o) { return map.containsKey(o); }
4406 <        public final boolean remove(Object o)   { return map.remove(o) != null; }
4403 >    /**
4404 >     * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in
4405 >     * which additions may optionally be enabled by mapping to a
4406 >     * common value.  This class cannot be directly instantiated.
4407 >     * See {@link #keySet() keySet()},
4408 >     * {@link #keySet(Object) keySet(V)},
4409 >     * {@link #newKeySet() newKeySet()},
4410 >     * {@link #newKeySet(int) newKeySet(int)}.
4411 >     *
4412 >     * @since 1.8
4413 >     */
4414 >    public static class KeySetView<K,V> extends CollectionView<K,V,K>
4415 >        implements Set<K>, java.io.Serializable {
4416 >        private static final long serialVersionUID = 7249069246763182397L;
4417 >        private final V value;
4418 >        KeySetView(ConcurrentHashMapV8<K,V> map, V value) {  // non-public
4419 >            super(map);
4420 >            this.value = value;
4421 >        }
4422 >
4423 >        /**
4424 >         * Returns the default mapped value for additions,
4425 >         * or {@code null} if additions are not supported.
4426 >         *
4427 >         * @return the default mapped value for additions, or {@code null}
4428 >         * if not supported
4429 >         */
4430 >        public V getMappedValue() { return value; }
4431 >
4432 >        /**
4433 >         * {@inheritDoc}
4434 >         * @throws NullPointerException if the specified key is null
4435 >         */
4436 >        public boolean contains(Object o) { return map.containsKey(o); }
4437 >
4438 >        /**
4439 >         * Removes the key from this map view, by removing the key (and its
4440 >         * corresponding value) from the backing map.  This method does
4441 >         * nothing if the key is not in the map.
4442 >         *
4443 >         * @param  o the key to be removed from the backing map
4444 >         * @return {@code true} if the backing map contained the specified key
4445 >         * @throws NullPointerException if the specified key is null
4446 >         */
4447 >        public boolean remove(Object o) { return map.remove(o) != null; }
4448  
4449 <        public final Iterator<K> iterator() {
4450 <            return new KeyIterator<K,V>(map);
4449 >        /**
4450 >         * @return an iterator over the keys of the backing map
4451 >         */
4452 >        public Iterator<K> iterator() {
4453 >            Node<K,V>[] t;
4454 >            ConcurrentHashMapV8<K,V> m = map;
4455 >            int f = (t = m.table) == null ? 0 : t.length;
4456 >            return new KeyIterator<K,V>(t, f, 0, f, m);
4457          }
4458 <        final Iterator<?> iter() {
4459 <            return new KeyIterator<K,V>(map);
4458 >
4459 >        /**
4460 >         * Adds the specified key to this set view by mapping the key to
4461 >         * the default mapped value in the backing map, if defined.
4462 >         *
4463 >         * @param e key to be added
4464 >         * @return {@code true} if this set changed as a result of the call
4465 >         * @throws NullPointerException if the specified key is null
4466 >         * @throws UnsupportedOperationException if no default mapped value
4467 >         * for additions was provided
4468 >         */
4469 >        public boolean add(K e) {
4470 >            V v;
4471 >            if ((v = value) == null)
4472 >                throw new UnsupportedOperationException();
4473 >            return map.putVal(e, v, true) == null;
4474          }
4475 <        public final boolean add(K e) {
4476 <            throw new UnsupportedOperationException();
4475 >
4476 >        /**
4477 >         * Adds all of the elements in the specified collection to this set,
4478 >         * as if by calling {@link #add} on each one.
4479 >         *
4480 >         * @param c the elements to be inserted into this set
4481 >         * @return {@code true} if this set changed as a result of the call
4482 >         * @throws NullPointerException if the collection or any of its
4483 >         * elements are {@code null}
4484 >         * @throws UnsupportedOperationException if no default mapped value
4485 >         * for additions was provided
4486 >         */
4487 >        public boolean addAll(Collection<? extends K> c) {
4488 >            boolean added = false;
4489 >            V v;
4490 >            if ((v = value) == null)
4491 >                throw new UnsupportedOperationException();
4492 >            for (K e : c) {
4493 >                if (map.putVal(e, v, true) == null)
4494 >                    added = true;
4495 >            }
4496 >            return added;
4497          }
4498 <        public final boolean addAll(Collection<? extends K> c) {
4499 <            throw new UnsupportedOperationException();
4498 >
4499 >        public int hashCode() {
4500 >            int h = 0;
4501 >            for (K e : this)
4502 >                h += e.hashCode();
4503 >            return h;
4504          }
4505 +
4506          public boolean equals(Object o) {
4507              Set<?> c;
4508              return ((o instanceof Set) &&
4509                      ((c = (Set<?>)o) == this ||
4510                       (containsAll(c) && c.containsAll(this))));
4511          }
4512 +
4513 +        public ConcurrentHashMapSpliterator<K> spliterator() {
4514 +            Node<K,V>[] t;
4515 +            ConcurrentHashMapV8<K,V> m = map;
4516 +            long n = m.sumCount();
4517 +            int f = (t = m.table) == null ? 0 : t.length;
4518 +            return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4519 +        }
4520 +
4521 +        public void forEach(Action<? super K> action) {
4522 +            if (action == null) throw new NullPointerException();
4523 +            Node<K,V>[] t;
4524 +            if ((t = map.table) != null) {
4525 +                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4526 +                for (Node<K,V> p; (p = it.advance()) != null; )
4527 +                    action.apply(p.key);
4528 +            }
4529 +        }
4530      }
4531  
4532 <    static final class Values<K,V> extends MapView<K,V>
4533 <        implements Collection<V> {
4534 <        Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
4535 <        public final boolean contains(Object o) { return map.containsValue(o); }
4532 >    /**
4533 >     * A view of a ConcurrentHashMapV8 as a {@link Collection} of
4534 >     * values, in which additions are disabled. This class cannot be
4535 >     * directly instantiated. See {@link #values()}.
4536 >     */
4537 >    static final class ValuesView<K,V> extends CollectionView<K,V,V>
4538 >        implements Collection<V>, java.io.Serializable {
4539 >        private static final long serialVersionUID = 2249069246763182397L;
4540 >        ValuesView(ConcurrentHashMapV8<K,V> map) { super(map); }
4541 >        public final boolean contains(Object o) {
4542 >            return map.containsValue(o);
4543 >        }
4544  
4545          public final boolean remove(Object o) {
4546              if (o != null) {
4547 <                Iterator<V> it = new ValueIterator<K,V>(map);
2250 <                while (it.hasNext()) {
4547 >                for (Iterator<V> it = iterator(); it.hasNext();) {
4548                      if (o.equals(it.next())) {
4549                          it.remove();
4550                          return true;
# Line 2256 | Line 4553 | public class ConcurrentHashMapV8<K, V>
4553              }
4554              return false;
4555          }
4556 +
4557          public final Iterator<V> iterator() {
4558 <            return new ValueIterator<K,V>(map);
4559 <        }
4560 <        final Iterator<?> iter() {
4561 <            return new ValueIterator<K,V>(map);
4558 >            ConcurrentHashMapV8<K,V> m = map;
4559 >            Node<K,V>[] t;
4560 >            int f = (t = m.table) == null ? 0 : t.length;
4561 >            return new ValueIterator<K,V>(t, f, 0, f, m);
4562          }
4563 +
4564          public final boolean add(V e) {
4565              throw new UnsupportedOperationException();
4566          }
4567          public final boolean addAll(Collection<? extends V> c) {
4568              throw new UnsupportedOperationException();
4569          }
4570 +
4571 +        public ConcurrentHashMapSpliterator<V> spliterator() {
4572 +            Node<K,V>[] t;
4573 +            ConcurrentHashMapV8<K,V> m = map;
4574 +            long n = m.sumCount();
4575 +            int f = (t = m.table) == null ? 0 : t.length;
4576 +            return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4577 +        }
4578 +
4579 +        public void forEach(Action<? super V> action) {
4580 +            if (action == null) throw new NullPointerException();
4581 +            Node<K,V>[] t;
4582 +            if ((t = map.table) != null) {
4583 +                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4584 +                for (Node<K,V> p; (p = it.advance()) != null; )
4585 +                    action.apply(p.val);
4586 +            }
4587 +        }
4588      }
4589  
4590 <    static final class EntrySet<K,V> extends MapView<K,V>
4591 <        implements Set<Map.Entry<K,V>> {
4592 <        EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
4590 >    /**
4591 >     * A view of a ConcurrentHashMapV8 as a {@link Set} of (key, value)
4592 >     * entries.  This class cannot be directly instantiated. See
4593 >     * {@link #entrySet()}.
4594 >     */
4595 >    static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4596 >        implements Set<Map.Entry<K,V>>, java.io.Serializable {
4597 >        private static final long serialVersionUID = 2249069246763182397L;
4598 >        EntrySetView(ConcurrentHashMapV8<K,V> map) { super(map); }
4599  
4600 <        public final boolean contains(Object o) {
4600 >        public boolean contains(Object o) {
4601              Object k, v, r; Map.Entry<?,?> e;
4602              return ((o instanceof Map.Entry) &&
4603                      (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
# Line 2283 | Line 4606 | public class ConcurrentHashMapV8<K, V>
4606                      (v == r || v.equals(r)));
4607          }
4608  
4609 <        public final boolean remove(Object o) {
4609 >        public boolean remove(Object o) {
4610              Object k, v; Map.Entry<?,?> e;
4611              return ((o instanceof Map.Entry) &&
4612                      (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
# Line 2291 | Line 4614 | public class ConcurrentHashMapV8<K, V>
4614                      map.remove(k, v));
4615          }
4616  
4617 <        public final Iterator<Map.Entry<K,V>> iterator() {
4618 <            return new EntryIterator<K,V>(map);
4617 >        /**
4618 >         * @return an iterator over the entries of the backing map
4619 >         */
4620 >        public Iterator<Map.Entry<K,V>> iterator() {
4621 >            ConcurrentHashMapV8<K,V> m = map;
4622 >            Node<K,V>[] t;
4623 >            int f = (t = m.table) == null ? 0 : t.length;
4624 >            return new EntryIterator<K,V>(t, f, 0, f, m);
4625          }
4626 <        final Iterator<?> iter() {
4627 <            return new SnapshotEntryIterator<K,V>(map);
4626 >
4627 >        public boolean add(Entry<K,V> e) {
4628 >            return map.putVal(e.getKey(), e.getValue(), false) == null;
4629          }
4630 <        public final boolean add(Entry<K,V> e) {
4631 <            throw new UnsupportedOperationException();
4630 >
4631 >        public boolean addAll(Collection<? extends Entry<K,V>> c) {
4632 >            boolean added = false;
4633 >            for (Entry<K,V> e : c) {
4634 >                if (add(e))
4635 >                    added = true;
4636 >            }
4637 >            return added;
4638          }
4639 <        public final boolean addAll(Collection<? extends Entry<K,V>> c) {
4640 <            throw new UnsupportedOperationException();
4639 >
4640 >        public final int hashCode() {
4641 >            int h = 0;
4642 >            Node<K,V>[] t;
4643 >            if ((t = map.table) != null) {
4644 >                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4645 >                for (Node<K,V> p; (p = it.advance()) != null; ) {
4646 >                    h += p.hashCode();
4647 >                }
4648 >            }
4649 >            return h;
4650          }
4651 <        public boolean equals(Object o) {
4651 >
4652 >        public final boolean equals(Object o) {
4653              Set<?> c;
4654              return ((o instanceof Set) &&
4655                      ((c = (Set<?>)o) == this ||
4656                       (containsAll(c) && c.containsAll(this))));
4657          }
4658 +
4659 +        public ConcurrentHashMapSpliterator<Map.Entry<K,V>> spliterator() {
4660 +            Node<K,V>[] t;
4661 +            ConcurrentHashMapV8<K,V> m = map;
4662 +            long n = m.sumCount();
4663 +            int f = (t = m.table) == null ? 0 : t.length;
4664 +            return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4665 +        }
4666 +
4667 +        public void forEach(Action<? super Map.Entry<K,V>> action) {
4668 +            if (action == null) throw new NullPointerException();
4669 +            Node<K,V>[] t;
4670 +            if ((t = map.table) != null) {
4671 +                Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4672 +                for (Node<K,V> p; (p = it.advance()) != null; )
4673 +                    action.apply(new MapEntry<K,V>(p.key, p.val, map));
4674 +            }
4675 +        }
4676 +
4677      }
4678  
4679 <    /* ---------------- Serialization Support -------------- */
4679 >    // -------------------------------------------------------
4680  
4681      /**
4682 <     * Stripped-down version of helper class used in previous version,
4683 <     * declared for the sake of serialization compatibility
4682 >     * Base class for bulk tasks. Repeats some fields and code from
4683 >     * class Traverser, because we need to subclass CountedCompleter.
4684       */
4685 <    static class Segment<K,V> implements Serializable {
4686 <        private static final long serialVersionUID = 2249069246763182397L;
4687 <        final float loadFactor;
4688 <        Segment(float lf) { this.loadFactor = lf; }
4685 >    abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4686 >        Node<K,V>[] tab;        // same as Traverser
4687 >        Node<K,V> next;
4688 >        int index;
4689 >        int baseIndex;
4690 >        int baseLimit;
4691 >        final int baseSize;
4692 >        int batch;              // split control
4693 >
4694 >        BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4695 >            super(par);
4696 >            this.batch = b;
4697 >            this.index = this.baseIndex = i;
4698 >            if ((this.tab = t) == null)
4699 >                this.baseSize = this.baseLimit = 0;
4700 >            else if (par == null)
4701 >                this.baseSize = this.baseLimit = t.length;
4702 >            else {
4703 >                this.baseLimit = f;
4704 >                this.baseSize = par.baseSize;
4705 >            }
4706 >        }
4707 >
4708 >        /**
4709 >         * Same as Traverser version
4710 >         */
4711 >        final Node<K,V> advance() {
4712 >            Node<K,V> e;
4713 >            if ((e = next) != null)
4714 >                e = e.next;
4715 >            for (;;) {
4716 >                Node<K,V>[] t; int i, n; K ek;  // must use locals in checks
4717 >                if (e != null)
4718 >                    return next = e;
4719 >                if (baseIndex >= baseLimit || (t = tab) == null ||
4720 >                    (n = t.length) <= (i = index) || i < 0)
4721 >                    return next = null;
4722 >                if ((e = tabAt(t, index)) != null && e.hash < 0) {
4723 >                    if (e instanceof ForwardingNode) {
4724 >                        tab = ((ForwardingNode<K,V>)e).nextTable;
4725 >                        e = null;
4726 >                        continue;
4727 >                    }
4728 >                    else if (e instanceof TreeBin)
4729 >                        e = ((TreeBin<K,V>)e).first;
4730 >                    else
4731 >                        e = null;
4732 >                }
4733 >                if ((index += baseSize) >= n)
4734 >                    index = ++baseIndex;    // visit upper slots if present
4735 >            }
4736 >        }
4737 >    }
4738 >
4739 >    /*
4740 >     * Task classes. Coded in a regular but ugly format/style to
4741 >     * simplify checks that each variant differs in the right way from
4742 >     * others. The null screenings exist because compilers cannot tell
4743 >     * that we've already null-checked task arguments, so we force
4744 >     * simplest hoisted bypass to help avoid convoluted traps.
4745 >     */
4746 >    @SuppressWarnings("serial")
4747 >    static final class ForEachKeyTask<K,V>
4748 >        extends BulkTask<K,V,Void> {
4749 >        final Action<? super K> action;
4750 >        ForEachKeyTask
4751 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4752 >             Action<? super K> action) {
4753 >            super(p, b, i, f, t);
4754 >            this.action = action;
4755 >        }
4756 >        public final void compute() {
4757 >            final Action<? super K> action;
4758 >            if ((action = this.action) != null) {
4759 >                for (int i = baseIndex, f, h; batch > 0 &&
4760 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4761 >                    addToPendingCount(1);
4762 >                    new ForEachKeyTask<K,V>
4763 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4764 >                         action).fork();
4765 >                }
4766 >                for (Node<K,V> p; (p = advance()) != null;)
4767 >                    action.apply(p.key);
4768 >                propagateCompletion();
4769 >            }
4770 >        }
4771 >    }
4772 >
4773 >    @SuppressWarnings("serial")
4774 >    static final class ForEachValueTask<K,V>
4775 >        extends BulkTask<K,V,Void> {
4776 >        final Action<? super V> action;
4777 >        ForEachValueTask
4778 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4779 >             Action<? super V> action) {
4780 >            super(p, b, i, f, t);
4781 >            this.action = action;
4782 >        }
4783 >        public final void compute() {
4784 >            final Action<? super V> action;
4785 >            if ((action = this.action) != null) {
4786 >                for (int i = baseIndex, f, h; batch > 0 &&
4787 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4788 >                    addToPendingCount(1);
4789 >                    new ForEachValueTask<K,V>
4790 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4791 >                         action).fork();
4792 >                }
4793 >                for (Node<K,V> p; (p = advance()) != null;)
4794 >                    action.apply(p.val);
4795 >                propagateCompletion();
4796 >            }
4797 >        }
4798 >    }
4799 >
4800 >    @SuppressWarnings("serial")
4801 >    static final class ForEachEntryTask<K,V>
4802 >        extends BulkTask<K,V,Void> {
4803 >        final Action<? super Entry<K,V>> action;
4804 >        ForEachEntryTask
4805 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4806 >             Action<? super Entry<K,V>> action) {
4807 >            super(p, b, i, f, t);
4808 >            this.action = action;
4809 >        }
4810 >        public final void compute() {
4811 >            final Action<? super Entry<K,V>> action;
4812 >            if ((action = this.action) != null) {
4813 >                for (int i = baseIndex, f, h; batch > 0 &&
4814 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4815 >                    addToPendingCount(1);
4816 >                    new ForEachEntryTask<K,V>
4817 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4818 >                         action).fork();
4819 >                }
4820 >                for (Node<K,V> p; (p = advance()) != null; )
4821 >                    action.apply(p);
4822 >                propagateCompletion();
4823 >            }
4824 >        }
4825 >    }
4826 >
4827 >    @SuppressWarnings("serial")
4828 >    static final class ForEachMappingTask<K,V>
4829 >        extends BulkTask<K,V,Void> {
4830 >        final BiAction<? super K, ? super V> action;
4831 >        ForEachMappingTask
4832 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4833 >             BiAction<? super K,? super V> action) {
4834 >            super(p, b, i, f, t);
4835 >            this.action = action;
4836 >        }
4837 >        public final void compute() {
4838 >            final BiAction<? super K, ? super V> action;
4839 >            if ((action = this.action) != null) {
4840 >                for (int i = baseIndex, f, h; batch > 0 &&
4841 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4842 >                    addToPendingCount(1);
4843 >                    new ForEachMappingTask<K,V>
4844 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4845 >                         action).fork();
4846 >                }
4847 >                for (Node<K,V> p; (p = advance()) != null; )
4848 >                    action.apply(p.key, p.val);
4849 >                propagateCompletion();
4850 >            }
4851 >        }
4852 >    }
4853 >
4854 >    @SuppressWarnings("serial")
4855 >    static final class ForEachTransformedKeyTask<K,V,U>
4856 >        extends BulkTask<K,V,Void> {
4857 >        final Fun<? super K, ? extends U> transformer;
4858 >        final Action<? super U> action;
4859 >        ForEachTransformedKeyTask
4860 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4861 >             Fun<? super K, ? extends U> transformer, Action<? super U> action) {
4862 >            super(p, b, i, f, t);
4863 >            this.transformer = transformer; this.action = action;
4864 >        }
4865 >        public final void compute() {
4866 >            final Fun<? super K, ? extends U> transformer;
4867 >            final Action<? super U> action;
4868 >            if ((transformer = this.transformer) != null &&
4869 >                (action = this.action) != null) {
4870 >                for (int i = baseIndex, f, h; batch > 0 &&
4871 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4872 >                    addToPendingCount(1);
4873 >                    new ForEachTransformedKeyTask<K,V,U>
4874 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4875 >                         transformer, action).fork();
4876 >                }
4877 >                for (Node<K,V> p; (p = advance()) != null; ) {
4878 >                    U u;
4879 >                    if ((u = transformer.apply(p.key)) != null)
4880 >                        action.apply(u);
4881 >                }
4882 >                propagateCompletion();
4883 >            }
4884 >        }
4885 >    }
4886 >
4887 >    @SuppressWarnings("serial")
4888 >    static final class ForEachTransformedValueTask<K,V,U>
4889 >        extends BulkTask<K,V,Void> {
4890 >        final Fun<? super V, ? extends U> transformer;
4891 >        final Action<? super U> action;
4892 >        ForEachTransformedValueTask
4893 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4894 >             Fun<? super V, ? extends U> transformer, Action<? super U> action) {
4895 >            super(p, b, i, f, t);
4896 >            this.transformer = transformer; this.action = action;
4897 >        }
4898 >        public final void compute() {
4899 >            final Fun<? super V, ? extends U> transformer;
4900 >            final Action<? super U> action;
4901 >            if ((transformer = this.transformer) != null &&
4902 >                (action = this.action) != null) {
4903 >                for (int i = baseIndex, f, h; batch > 0 &&
4904 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4905 >                    addToPendingCount(1);
4906 >                    new ForEachTransformedValueTask<K,V,U>
4907 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4908 >                         transformer, action).fork();
4909 >                }
4910 >                for (Node<K,V> p; (p = advance()) != null; ) {
4911 >                    U u;
4912 >                    if ((u = transformer.apply(p.val)) != null)
4913 >                        action.apply(u);
4914 >                }
4915 >                propagateCompletion();
4916 >            }
4917 >        }
4918 >    }
4919 >
4920 >    @SuppressWarnings("serial")
4921 >    static final class ForEachTransformedEntryTask<K,V,U>
4922 >        extends BulkTask<K,V,Void> {
4923 >        final Fun<Map.Entry<K,V>, ? extends U> transformer;
4924 >        final Action<? super U> action;
4925 >        ForEachTransformedEntryTask
4926 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4927 >             Fun<Map.Entry<K,V>, ? extends U> transformer, Action<? super U> action) {
4928 >            super(p, b, i, f, t);
4929 >            this.transformer = transformer; this.action = action;
4930 >        }
4931 >        public final void compute() {
4932 >            final Fun<Map.Entry<K,V>, ? extends U> transformer;
4933 >            final Action<? super U> action;
4934 >            if ((transformer = this.transformer) != null &&
4935 >                (action = this.action) != null) {
4936 >                for (int i = baseIndex, f, h; batch > 0 &&
4937 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4938 >                    addToPendingCount(1);
4939 >                    new ForEachTransformedEntryTask<K,V,U>
4940 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4941 >                         transformer, action).fork();
4942 >                }
4943 >                for (Node<K,V> p; (p = advance()) != null; ) {
4944 >                    U u;
4945 >                    if ((u = transformer.apply(p)) != null)
4946 >                        action.apply(u);
4947 >                }
4948 >                propagateCompletion();
4949 >            }
4950 >        }
4951 >    }
4952 >
4953 >    @SuppressWarnings("serial")
4954 >    static final class ForEachTransformedMappingTask<K,V,U>
4955 >        extends BulkTask<K,V,Void> {
4956 >        final BiFun<? super K, ? super V, ? extends U> transformer;
4957 >        final Action<? super U> action;
4958 >        ForEachTransformedMappingTask
4959 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4960 >             BiFun<? super K, ? super V, ? extends U> transformer,
4961 >             Action<? super U> action) {
4962 >            super(p, b, i, f, t);
4963 >            this.transformer = transformer; this.action = action;
4964 >        }
4965 >        public final void compute() {
4966 >            final BiFun<? super K, ? super V, ? extends U> transformer;
4967 >            final Action<? super U> action;
4968 >            if ((transformer = this.transformer) != null &&
4969 >                (action = this.action) != null) {
4970 >                for (int i = baseIndex, f, h; batch > 0 &&
4971 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
4972 >                    addToPendingCount(1);
4973 >                    new ForEachTransformedMappingTask<K,V,U>
4974 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
4975 >                         transformer, action).fork();
4976 >                }
4977 >                for (Node<K,V> p; (p = advance()) != null; ) {
4978 >                    U u;
4979 >                    if ((u = transformer.apply(p.key, p.val)) != null)
4980 >                        action.apply(u);
4981 >                }
4982 >                propagateCompletion();
4983 >            }
4984 >        }
4985 >    }
4986 >
4987 >    @SuppressWarnings("serial")
4988 >    static final class SearchKeysTask<K,V,U>
4989 >        extends BulkTask<K,V,U> {
4990 >        final Fun<? super K, ? extends U> searchFunction;
4991 >        final AtomicReference<U> result;
4992 >        SearchKeysTask
4993 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4994 >             Fun<? super K, ? extends U> searchFunction,
4995 >             AtomicReference<U> result) {
4996 >            super(p, b, i, f, t);
4997 >            this.searchFunction = searchFunction; this.result = result;
4998 >        }
4999 >        public final U getRawResult() { return result.get(); }
5000 >        public final void compute() {
5001 >            final Fun<? super K, ? extends U> searchFunction;
5002 >            final AtomicReference<U> result;
5003 >            if ((searchFunction = this.searchFunction) != null &&
5004 >                (result = this.result) != null) {
5005 >                for (int i = baseIndex, f, h; batch > 0 &&
5006 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5007 >                    if (result.get() != null)
5008 >                        return;
5009 >                    addToPendingCount(1);
5010 >                    new SearchKeysTask<K,V,U>
5011 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
5012 >                         searchFunction, result).fork();
5013 >                }
5014 >                while (result.get() == null) {
5015 >                    U u;
5016 >                    Node<K,V> p;
5017 >                    if ((p = advance()) == null) {
5018 >                        propagateCompletion();
5019 >                        break;
5020 >                    }
5021 >                    if ((u = searchFunction.apply(p.key)) != null) {
5022 >                        if (result.compareAndSet(null, u))
5023 >                            quietlyCompleteRoot();
5024 >                        break;
5025 >                    }
5026 >                }
5027 >            }
5028 >        }
5029 >    }
5030 >
5031 >    @SuppressWarnings("serial")
5032 >    static final class SearchValuesTask<K,V,U>
5033 >        extends BulkTask<K,V,U> {
5034 >        final Fun<? super V, ? extends U> searchFunction;
5035 >        final AtomicReference<U> result;
5036 >        SearchValuesTask
5037 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5038 >             Fun<? super V, ? extends U> searchFunction,
5039 >             AtomicReference<U> result) {
5040 >            super(p, b, i, f, t);
5041 >            this.searchFunction = searchFunction; this.result = result;
5042 >        }
5043 >        public final U getRawResult() { return result.get(); }
5044 >        public final void compute() {
5045 >            final Fun<? super V, ? extends U> searchFunction;
5046 >            final AtomicReference<U> result;
5047 >            if ((searchFunction = this.searchFunction) != null &&
5048 >                (result = this.result) != null) {
5049 >                for (int i = baseIndex, f, h; batch > 0 &&
5050 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5051 >                    if (result.get() != null)
5052 >                        return;
5053 >                    addToPendingCount(1);
5054 >                    new SearchValuesTask<K,V,U>
5055 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
5056 >                         searchFunction, result).fork();
5057 >                }
5058 >                while (result.get() == null) {
5059 >                    U u;
5060 >                    Node<K,V> p;
5061 >                    if ((p = advance()) == null) {
5062 >                        propagateCompletion();
5063 >                        break;
5064 >                    }
5065 >                    if ((u = searchFunction.apply(p.val)) != null) {
5066 >                        if (result.compareAndSet(null, u))
5067 >                            quietlyCompleteRoot();
5068 >                        break;
5069 >                    }
5070 >                }
5071 >            }
5072 >        }
5073 >    }
5074 >
5075 >    @SuppressWarnings("serial")
5076 >    static final class SearchEntriesTask<K,V,U>
5077 >        extends BulkTask<K,V,U> {
5078 >        final Fun<Entry<K,V>, ? extends U> searchFunction;
5079 >        final AtomicReference<U> result;
5080 >        SearchEntriesTask
5081 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5082 >             Fun<Entry<K,V>, ? extends U> searchFunction,
5083 >             AtomicReference<U> result) {
5084 >            super(p, b, i, f, t);
5085 >            this.searchFunction = searchFunction; this.result = result;
5086 >        }
5087 >        public final U getRawResult() { return result.get(); }
5088 >        public final void compute() {
5089 >            final Fun<Entry<K,V>, ? extends U> searchFunction;
5090 >            final AtomicReference<U> result;
5091 >            if ((searchFunction = this.searchFunction) != null &&
5092 >                (result = this.result) != null) {
5093 >                for (int i = baseIndex, f, h; batch > 0 &&
5094 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5095 >                    if (result.get() != null)
5096 >                        return;
5097 >                    addToPendingCount(1);
5098 >                    new SearchEntriesTask<K,V,U>
5099 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
5100 >                         searchFunction, result).fork();
5101 >                }
5102 >                while (result.get() == null) {
5103 >                    U u;
5104 >                    Node<K,V> p;
5105 >                    if ((p = advance()) == null) {
5106 >                        propagateCompletion();
5107 >                        break;
5108 >                    }
5109 >                    if ((u = searchFunction.apply(p)) != null) {
5110 >                        if (result.compareAndSet(null, u))
5111 >                            quietlyCompleteRoot();
5112 >                        return;
5113 >                    }
5114 >                }
5115 >            }
5116 >        }
5117 >    }
5118 >
5119 >    @SuppressWarnings("serial")
5120 >    static final class SearchMappingsTask<K,V,U>
5121 >        extends BulkTask<K,V,U> {
5122 >        final BiFun<? super K, ? super V, ? extends U> searchFunction;
5123 >        final AtomicReference<U> result;
5124 >        SearchMappingsTask
5125 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5126 >             BiFun<? super K, ? super V, ? extends U> searchFunction,
5127 >             AtomicReference<U> result) {
5128 >            super(p, b, i, f, t);
5129 >            this.searchFunction = searchFunction; this.result = result;
5130 >        }
5131 >        public final U getRawResult() { return result.get(); }
5132 >        public final void compute() {
5133 >            final BiFun<? super K, ? super V, ? extends U> searchFunction;
5134 >            final AtomicReference<U> result;
5135 >            if ((searchFunction = this.searchFunction) != null &&
5136 >                (result = this.result) != null) {
5137 >                for (int i = baseIndex, f, h; batch > 0 &&
5138 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5139 >                    if (result.get() != null)
5140 >                        return;
5141 >                    addToPendingCount(1);
5142 >                    new SearchMappingsTask<K,V,U>
5143 >                        (this, batch >>>= 1, baseLimit = h, f, tab,
5144 >                         searchFunction, result).fork();
5145 >                }
5146 >                while (result.get() == null) {
5147 >                    U u;
5148 >                    Node<K,V> p;
5149 >                    if ((p = advance()) == null) {
5150 >                        propagateCompletion();
5151 >                        break;
5152 >                    }
5153 >                    if ((u = searchFunction.apply(p.key, p.val)) != null) {
5154 >                        if (result.compareAndSet(null, u))
5155 >                            quietlyCompleteRoot();
5156 >                        break;
5157 >                    }
5158 >                }
5159 >            }
5160 >        }
5161 >    }
5162 >
5163 >    @SuppressWarnings("serial")
5164 >    static final class ReduceKeysTask<K,V>
5165 >        extends BulkTask<K,V,K> {
5166 >        final BiFun<? super K, ? super K, ? extends K> reducer;
5167 >        K result;
5168 >        ReduceKeysTask<K,V> rights, nextRight;
5169 >        ReduceKeysTask
5170 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5171 >             ReduceKeysTask<K,V> nextRight,
5172 >             BiFun<? super K, ? super K, ? extends K> reducer) {
5173 >            super(p, b, i, f, t); this.nextRight = nextRight;
5174 >            this.reducer = reducer;
5175 >        }
5176 >        public final K getRawResult() { return result; }
5177 >        public final void compute() {
5178 >            final BiFun<? super K, ? super K, ? extends K> reducer;
5179 >            if ((reducer = this.reducer) != null) {
5180 >                for (int i = baseIndex, f, h; batch > 0 &&
5181 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5182 >                    addToPendingCount(1);
5183 >                    (rights = new ReduceKeysTask<K,V>
5184 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5185 >                      rights, reducer)).fork();
5186 >                }
5187 >                K r = null;
5188 >                for (Node<K,V> p; (p = advance()) != null; ) {
5189 >                    K u = p.key;
5190 >                    r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5191 >                }
5192 >                result = r;
5193 >                CountedCompleter<?> c;
5194 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5195 >                    @SuppressWarnings("unchecked") ReduceKeysTask<K,V>
5196 >                        t = (ReduceKeysTask<K,V>)c,
5197 >                        s = t.rights;
5198 >                    while (s != null) {
5199 >                        K tr, sr;
5200 >                        if ((sr = s.result) != null)
5201 >                            t.result = (((tr = t.result) == null) ? sr :
5202 >                                        reducer.apply(tr, sr));
5203 >                        s = t.rights = s.nextRight;
5204 >                    }
5205 >                }
5206 >            }
5207 >        }
5208 >    }
5209 >
5210 >    @SuppressWarnings("serial")
5211 >    static final class ReduceValuesTask<K,V>
5212 >        extends BulkTask<K,V,V> {
5213 >        final BiFun<? super V, ? super V, ? extends V> reducer;
5214 >        V result;
5215 >        ReduceValuesTask<K,V> rights, nextRight;
5216 >        ReduceValuesTask
5217 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5218 >             ReduceValuesTask<K,V> nextRight,
5219 >             BiFun<? super V, ? super V, ? extends V> reducer) {
5220 >            super(p, b, i, f, t); this.nextRight = nextRight;
5221 >            this.reducer = reducer;
5222 >        }
5223 >        public final V getRawResult() { return result; }
5224 >        public final void compute() {
5225 >            final BiFun<? super V, ? super V, ? extends V> reducer;
5226 >            if ((reducer = this.reducer) != null) {
5227 >                for (int i = baseIndex, f, h; batch > 0 &&
5228 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5229 >                    addToPendingCount(1);
5230 >                    (rights = new ReduceValuesTask<K,V>
5231 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5232 >                      rights, reducer)).fork();
5233 >                }
5234 >                V r = null;
5235 >                for (Node<K,V> p; (p = advance()) != null; ) {
5236 >                    V v = p.val;
5237 >                    r = (r == null) ? v : reducer.apply(r, v);
5238 >                }
5239 >                result = r;
5240 >                CountedCompleter<?> c;
5241 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5242 >                    @SuppressWarnings("unchecked") ReduceValuesTask<K,V>
5243 >                        t = (ReduceValuesTask<K,V>)c,
5244 >                        s = t.rights;
5245 >                    while (s != null) {
5246 >                        V tr, sr;
5247 >                        if ((sr = s.result) != null)
5248 >                            t.result = (((tr = t.result) == null) ? sr :
5249 >                                        reducer.apply(tr, sr));
5250 >                        s = t.rights = s.nextRight;
5251 >                    }
5252 >                }
5253 >            }
5254 >        }
5255 >    }
5256 >
5257 >    @SuppressWarnings("serial")
5258 >    static final class ReduceEntriesTask<K,V>
5259 >        extends BulkTask<K,V,Map.Entry<K,V>> {
5260 >        final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5261 >        Map.Entry<K,V> result;
5262 >        ReduceEntriesTask<K,V> rights, nextRight;
5263 >        ReduceEntriesTask
5264 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5265 >             ReduceEntriesTask<K,V> nextRight,
5266 >             BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5267 >            super(p, b, i, f, t); this.nextRight = nextRight;
5268 >            this.reducer = reducer;
5269 >        }
5270 >        public final Map.Entry<K,V> getRawResult() { return result; }
5271 >        public final void compute() {
5272 >            final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5273 >            if ((reducer = this.reducer) != null) {
5274 >                for (int i = baseIndex, f, h; batch > 0 &&
5275 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5276 >                    addToPendingCount(1);
5277 >                    (rights = new ReduceEntriesTask<K,V>
5278 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5279 >                      rights, reducer)).fork();
5280 >                }
5281 >                Map.Entry<K,V> r = null;
5282 >                for (Node<K,V> p; (p = advance()) != null; )
5283 >                    r = (r == null) ? p : reducer.apply(r, p);
5284 >                result = r;
5285 >                CountedCompleter<?> c;
5286 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5287 >                    @SuppressWarnings("unchecked") ReduceEntriesTask<K,V>
5288 >                        t = (ReduceEntriesTask<K,V>)c,
5289 >                        s = t.rights;
5290 >                    while (s != null) {
5291 >                        Map.Entry<K,V> tr, sr;
5292 >                        if ((sr = s.result) != null)
5293 >                            t.result = (((tr = t.result) == null) ? sr :
5294 >                                        reducer.apply(tr, sr));
5295 >                        s = t.rights = s.nextRight;
5296 >                    }
5297 >                }
5298 >            }
5299 >        }
5300 >    }
5301 >
5302 >    @SuppressWarnings("serial")
5303 >    static final class MapReduceKeysTask<K,V,U>
5304 >        extends BulkTask<K,V,U> {
5305 >        final Fun<? super K, ? extends U> transformer;
5306 >        final BiFun<? super U, ? super U, ? extends U> reducer;
5307 >        U result;
5308 >        MapReduceKeysTask<K,V,U> rights, nextRight;
5309 >        MapReduceKeysTask
5310 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5311 >             MapReduceKeysTask<K,V,U> nextRight,
5312 >             Fun<? super K, ? extends U> transformer,
5313 >             BiFun<? super U, ? super U, ? extends U> reducer) {
5314 >            super(p, b, i, f, t); this.nextRight = nextRight;
5315 >            this.transformer = transformer;
5316 >            this.reducer = reducer;
5317 >        }
5318 >        public final U getRawResult() { return result; }
5319 >        public final void compute() {
5320 >            final Fun<? super K, ? extends U> transformer;
5321 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5322 >            if ((transformer = this.transformer) != null &&
5323 >                (reducer = this.reducer) != null) {
5324 >                for (int i = baseIndex, f, h; batch > 0 &&
5325 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5326 >                    addToPendingCount(1);
5327 >                    (rights = new MapReduceKeysTask<K,V,U>
5328 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5329 >                      rights, transformer, reducer)).fork();
5330 >                }
5331 >                U r = null;
5332 >                for (Node<K,V> p; (p = advance()) != null; ) {
5333 >                    U u;
5334 >                    if ((u = transformer.apply(p.key)) != null)
5335 >                        r = (r == null) ? u : reducer.apply(r, u);
5336 >                }
5337 >                result = r;
5338 >                CountedCompleter<?> c;
5339 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5340 >                    @SuppressWarnings("unchecked") MapReduceKeysTask<K,V,U>
5341 >                        t = (MapReduceKeysTask<K,V,U>)c,
5342 >                        s = t.rights;
5343 >                    while (s != null) {
5344 >                        U tr, sr;
5345 >                        if ((sr = s.result) != null)
5346 >                            t.result = (((tr = t.result) == null) ? sr :
5347 >                                        reducer.apply(tr, sr));
5348 >                        s = t.rights = s.nextRight;
5349 >                    }
5350 >                }
5351 >            }
5352 >        }
5353 >    }
5354 >
5355 >    @SuppressWarnings("serial")
5356 >    static final class MapReduceValuesTask<K,V,U>
5357 >        extends BulkTask<K,V,U> {
5358 >        final Fun<? super V, ? extends U> transformer;
5359 >        final BiFun<? super U, ? super U, ? extends U> reducer;
5360 >        U result;
5361 >        MapReduceValuesTask<K,V,U> rights, nextRight;
5362 >        MapReduceValuesTask
5363 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5364 >             MapReduceValuesTask<K,V,U> nextRight,
5365 >             Fun<? super V, ? extends U> transformer,
5366 >             BiFun<? super U, ? super U, ? extends U> reducer) {
5367 >            super(p, b, i, f, t); this.nextRight = nextRight;
5368 >            this.transformer = transformer;
5369 >            this.reducer = reducer;
5370 >        }
5371 >        public final U getRawResult() { return result; }
5372 >        public final void compute() {
5373 >            final Fun<? super V, ? extends U> transformer;
5374 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5375 >            if ((transformer = this.transformer) != null &&
5376 >                (reducer = this.reducer) != null) {
5377 >                for (int i = baseIndex, f, h; batch > 0 &&
5378 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5379 >                    addToPendingCount(1);
5380 >                    (rights = new MapReduceValuesTask<K,V,U>
5381 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5382 >                      rights, transformer, reducer)).fork();
5383 >                }
5384 >                U r = null;
5385 >                for (Node<K,V> p; (p = advance()) != null; ) {
5386 >                    U u;
5387 >                    if ((u = transformer.apply(p.val)) != null)
5388 >                        r = (r == null) ? u : reducer.apply(r, u);
5389 >                }
5390 >                result = r;
5391 >                CountedCompleter<?> c;
5392 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5393 >                    @SuppressWarnings("unchecked") MapReduceValuesTask<K,V,U>
5394 >                        t = (MapReduceValuesTask<K,V,U>)c,
5395 >                        s = t.rights;
5396 >                    while (s != null) {
5397 >                        U tr, sr;
5398 >                        if ((sr = s.result) != null)
5399 >                            t.result = (((tr = t.result) == null) ? sr :
5400 >                                        reducer.apply(tr, sr));
5401 >                        s = t.rights = s.nextRight;
5402 >                    }
5403 >                }
5404 >            }
5405 >        }
5406 >    }
5407 >
5408 >    @SuppressWarnings("serial")
5409 >    static final class MapReduceEntriesTask<K,V,U>
5410 >        extends BulkTask<K,V,U> {
5411 >        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5412 >        final BiFun<? super U, ? super U, ? extends U> reducer;
5413 >        U result;
5414 >        MapReduceEntriesTask<K,V,U> rights, nextRight;
5415 >        MapReduceEntriesTask
5416 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5417 >             MapReduceEntriesTask<K,V,U> nextRight,
5418 >             Fun<Map.Entry<K,V>, ? extends U> transformer,
5419 >             BiFun<? super U, ? super U, ? extends U> reducer) {
5420 >            super(p, b, i, f, t); this.nextRight = nextRight;
5421 >            this.transformer = transformer;
5422 >            this.reducer = reducer;
5423 >        }
5424 >        public final U getRawResult() { return result; }
5425 >        public final void compute() {
5426 >            final Fun<Map.Entry<K,V>, ? extends U> transformer;
5427 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5428 >            if ((transformer = this.transformer) != null &&
5429 >                (reducer = this.reducer) != null) {
5430 >                for (int i = baseIndex, f, h; batch > 0 &&
5431 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5432 >                    addToPendingCount(1);
5433 >                    (rights = new MapReduceEntriesTask<K,V,U>
5434 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5435 >                      rights, transformer, reducer)).fork();
5436 >                }
5437 >                U r = null;
5438 >                for (Node<K,V> p; (p = advance()) != null; ) {
5439 >                    U u;
5440 >                    if ((u = transformer.apply(p)) != null)
5441 >                        r = (r == null) ? u : reducer.apply(r, u);
5442 >                }
5443 >                result = r;
5444 >                CountedCompleter<?> c;
5445 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5446 >                    @SuppressWarnings("unchecked") MapReduceEntriesTask<K,V,U>
5447 >                        t = (MapReduceEntriesTask<K,V,U>)c,
5448 >                        s = t.rights;
5449 >                    while (s != null) {
5450 >                        U tr, sr;
5451 >                        if ((sr = s.result) != null)
5452 >                            t.result = (((tr = t.result) == null) ? sr :
5453 >                                        reducer.apply(tr, sr));
5454 >                        s = t.rights = s.nextRight;
5455 >                    }
5456 >                }
5457 >            }
5458 >        }
5459 >    }
5460 >
5461 >    @SuppressWarnings("serial")
5462 >    static final class MapReduceMappingsTask<K,V,U>
5463 >        extends BulkTask<K,V,U> {
5464 >        final BiFun<? super K, ? super V, ? extends U> transformer;
5465 >        final BiFun<? super U, ? super U, ? extends U> reducer;
5466 >        U result;
5467 >        MapReduceMappingsTask<K,V,U> rights, nextRight;
5468 >        MapReduceMappingsTask
5469 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5470 >             MapReduceMappingsTask<K,V,U> nextRight,
5471 >             BiFun<? super K, ? super V, ? extends U> transformer,
5472 >             BiFun<? super U, ? super U, ? extends U> reducer) {
5473 >            super(p, b, i, f, t); this.nextRight = nextRight;
5474 >            this.transformer = transformer;
5475 >            this.reducer = reducer;
5476 >        }
5477 >        public final U getRawResult() { return result; }
5478 >        public final void compute() {
5479 >            final BiFun<? super K, ? super V, ? extends U> transformer;
5480 >            final BiFun<? super U, ? super U, ? extends U> reducer;
5481 >            if ((transformer = this.transformer) != null &&
5482 >                (reducer = this.reducer) != null) {
5483 >                for (int i = baseIndex, f, h; batch > 0 &&
5484 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5485 >                    addToPendingCount(1);
5486 >                    (rights = new MapReduceMappingsTask<K,V,U>
5487 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5488 >                      rights, transformer, reducer)).fork();
5489 >                }
5490 >                U r = null;
5491 >                for (Node<K,V> p; (p = advance()) != null; ) {
5492 >                    U u;
5493 >                    if ((u = transformer.apply(p.key, p.val)) != null)
5494 >                        r = (r == null) ? u : reducer.apply(r, u);
5495 >                }
5496 >                result = r;
5497 >                CountedCompleter<?> c;
5498 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5499 >                    @SuppressWarnings("unchecked") MapReduceMappingsTask<K,V,U>
5500 >                        t = (MapReduceMappingsTask<K,V,U>)c,
5501 >                        s = t.rights;
5502 >                    while (s != null) {
5503 >                        U tr, sr;
5504 >                        if ((sr = s.result) != null)
5505 >                            t.result = (((tr = t.result) == null) ? sr :
5506 >                                        reducer.apply(tr, sr));
5507 >                        s = t.rights = s.nextRight;
5508 >                    }
5509 >                }
5510 >            }
5511 >        }
5512 >    }
5513 >
5514 >    @SuppressWarnings("serial")
5515 >    static final class MapReduceKeysToDoubleTask<K,V>
5516 >        extends BulkTask<K,V,Double> {
5517 >        final ObjectToDouble<? super K> transformer;
5518 >        final DoubleByDoubleToDouble reducer;
5519 >        final double basis;
5520 >        double result;
5521 >        MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5522 >        MapReduceKeysToDoubleTask
5523 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5524 >             MapReduceKeysToDoubleTask<K,V> nextRight,
5525 >             ObjectToDouble<? super K> transformer,
5526 >             double basis,
5527 >             DoubleByDoubleToDouble reducer) {
5528 >            super(p, b, i, f, t); this.nextRight = nextRight;
5529 >            this.transformer = transformer;
5530 >            this.basis = basis; this.reducer = reducer;
5531 >        }
5532 >        public final Double getRawResult() { return result; }
5533 >        public final void compute() {
5534 >            final ObjectToDouble<? super K> transformer;
5535 >            final DoubleByDoubleToDouble reducer;
5536 >            if ((transformer = this.transformer) != null &&
5537 >                (reducer = this.reducer) != null) {
5538 >                double r = this.basis;
5539 >                for (int i = baseIndex, f, h; batch > 0 &&
5540 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5541 >                    addToPendingCount(1);
5542 >                    (rights = new MapReduceKeysToDoubleTask<K,V>
5543 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5544 >                      rights, transformer, r, reducer)).fork();
5545 >                }
5546 >                for (Node<K,V> p; (p = advance()) != null; )
5547 >                    r = reducer.apply(r, transformer.apply(p.key));
5548 >                result = r;
5549 >                CountedCompleter<?> c;
5550 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5551 >                    @SuppressWarnings("unchecked") MapReduceKeysToDoubleTask<K,V>
5552 >                        t = (MapReduceKeysToDoubleTask<K,V>)c,
5553 >                        s = t.rights;
5554 >                    while (s != null) {
5555 >                        t.result = reducer.apply(t.result, s.result);
5556 >                        s = t.rights = s.nextRight;
5557 >                    }
5558 >                }
5559 >            }
5560 >        }
5561 >    }
5562 >
5563 >    @SuppressWarnings("serial")
5564 >    static final class MapReduceValuesToDoubleTask<K,V>
5565 >        extends BulkTask<K,V,Double> {
5566 >        final ObjectToDouble<? super V> transformer;
5567 >        final DoubleByDoubleToDouble reducer;
5568 >        final double basis;
5569 >        double result;
5570 >        MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5571 >        MapReduceValuesToDoubleTask
5572 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5573 >             MapReduceValuesToDoubleTask<K,V> nextRight,
5574 >             ObjectToDouble<? super V> transformer,
5575 >             double basis,
5576 >             DoubleByDoubleToDouble reducer) {
5577 >            super(p, b, i, f, t); this.nextRight = nextRight;
5578 >            this.transformer = transformer;
5579 >            this.basis = basis; this.reducer = reducer;
5580 >        }
5581 >        public final Double getRawResult() { return result; }
5582 >        public final void compute() {
5583 >            final ObjectToDouble<? super V> transformer;
5584 >            final DoubleByDoubleToDouble reducer;
5585 >            if ((transformer = this.transformer) != null &&
5586 >                (reducer = this.reducer) != null) {
5587 >                double r = this.basis;
5588 >                for (int i = baseIndex, f, h; batch > 0 &&
5589 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5590 >                    addToPendingCount(1);
5591 >                    (rights = new MapReduceValuesToDoubleTask<K,V>
5592 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5593 >                      rights, transformer, r, reducer)).fork();
5594 >                }
5595 >                for (Node<K,V> p; (p = advance()) != null; )
5596 >                    r = reducer.apply(r, transformer.apply(p.val));
5597 >                result = r;
5598 >                CountedCompleter<?> c;
5599 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5600 >                    @SuppressWarnings("unchecked") MapReduceValuesToDoubleTask<K,V>
5601 >                        t = (MapReduceValuesToDoubleTask<K,V>)c,
5602 >                        s = t.rights;
5603 >                    while (s != null) {
5604 >                        t.result = reducer.apply(t.result, s.result);
5605 >                        s = t.rights = s.nextRight;
5606 >                    }
5607 >                }
5608 >            }
5609 >        }
5610 >    }
5611 >
5612 >    @SuppressWarnings("serial")
5613 >    static final class MapReduceEntriesToDoubleTask<K,V>
5614 >        extends BulkTask<K,V,Double> {
5615 >        final ObjectToDouble<Map.Entry<K,V>> transformer;
5616 >        final DoubleByDoubleToDouble reducer;
5617 >        final double basis;
5618 >        double result;
5619 >        MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5620 >        MapReduceEntriesToDoubleTask
5621 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5622 >             MapReduceEntriesToDoubleTask<K,V> nextRight,
5623 >             ObjectToDouble<Map.Entry<K,V>> transformer,
5624 >             double basis,
5625 >             DoubleByDoubleToDouble reducer) {
5626 >            super(p, b, i, f, t); this.nextRight = nextRight;
5627 >            this.transformer = transformer;
5628 >            this.basis = basis; this.reducer = reducer;
5629 >        }
5630 >        public final Double getRawResult() { return result; }
5631 >        public final void compute() {
5632 >            final ObjectToDouble<Map.Entry<K,V>> transformer;
5633 >            final DoubleByDoubleToDouble reducer;
5634 >            if ((transformer = this.transformer) != null &&
5635 >                (reducer = this.reducer) != null) {
5636 >                double r = this.basis;
5637 >                for (int i = baseIndex, f, h; batch > 0 &&
5638 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5639 >                    addToPendingCount(1);
5640 >                    (rights = new MapReduceEntriesToDoubleTask<K,V>
5641 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5642 >                      rights, transformer, r, reducer)).fork();
5643 >                }
5644 >                for (Node<K,V> p; (p = advance()) != null; )
5645 >                    r = reducer.apply(r, transformer.apply(p));
5646 >                result = r;
5647 >                CountedCompleter<?> c;
5648 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5649 >                    @SuppressWarnings("unchecked") MapReduceEntriesToDoubleTask<K,V>
5650 >                        t = (MapReduceEntriesToDoubleTask<K,V>)c,
5651 >                        s = t.rights;
5652 >                    while (s != null) {
5653 >                        t.result = reducer.apply(t.result, s.result);
5654 >                        s = t.rights = s.nextRight;
5655 >                    }
5656 >                }
5657 >            }
5658 >        }
5659 >    }
5660 >
5661 >    @SuppressWarnings("serial")
5662 >    static final class MapReduceMappingsToDoubleTask<K,V>
5663 >        extends BulkTask<K,V,Double> {
5664 >        final ObjectByObjectToDouble<? super K, ? super V> transformer;
5665 >        final DoubleByDoubleToDouble reducer;
5666 >        final double basis;
5667 >        double result;
5668 >        MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5669 >        MapReduceMappingsToDoubleTask
5670 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5671 >             MapReduceMappingsToDoubleTask<K,V> nextRight,
5672 >             ObjectByObjectToDouble<? super K, ? super V> transformer,
5673 >             double basis,
5674 >             DoubleByDoubleToDouble reducer) {
5675 >            super(p, b, i, f, t); this.nextRight = nextRight;
5676 >            this.transformer = transformer;
5677 >            this.basis = basis; this.reducer = reducer;
5678 >        }
5679 >        public final Double getRawResult() { return result; }
5680 >        public final void compute() {
5681 >            final ObjectByObjectToDouble<? super K, ? super V> transformer;
5682 >            final DoubleByDoubleToDouble reducer;
5683 >            if ((transformer = this.transformer) != null &&
5684 >                (reducer = this.reducer) != null) {
5685 >                double r = this.basis;
5686 >                for (int i = baseIndex, f, h; batch > 0 &&
5687 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5688 >                    addToPendingCount(1);
5689 >                    (rights = new MapReduceMappingsToDoubleTask<K,V>
5690 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5691 >                      rights, transformer, r, reducer)).fork();
5692 >                }
5693 >                for (Node<K,V> p; (p = advance()) != null; )
5694 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5695 >                result = r;
5696 >                CountedCompleter<?> c;
5697 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5698 >                    @SuppressWarnings("unchecked") MapReduceMappingsToDoubleTask<K,V>
5699 >                        t = (MapReduceMappingsToDoubleTask<K,V>)c,
5700 >                        s = t.rights;
5701 >                    while (s != null) {
5702 >                        t.result = reducer.apply(t.result, s.result);
5703 >                        s = t.rights = s.nextRight;
5704 >                    }
5705 >                }
5706 >            }
5707 >        }
5708 >    }
5709 >
5710 >    @SuppressWarnings("serial")
5711 >    static final class MapReduceKeysToLongTask<K,V>
5712 >        extends BulkTask<K,V,Long> {
5713 >        final ObjectToLong<? super K> transformer;
5714 >        final LongByLongToLong reducer;
5715 >        final long basis;
5716 >        long result;
5717 >        MapReduceKeysToLongTask<K,V> rights, nextRight;
5718 >        MapReduceKeysToLongTask
5719 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5720 >             MapReduceKeysToLongTask<K,V> nextRight,
5721 >             ObjectToLong<? super K> transformer,
5722 >             long basis,
5723 >             LongByLongToLong reducer) {
5724 >            super(p, b, i, f, t); this.nextRight = nextRight;
5725 >            this.transformer = transformer;
5726 >            this.basis = basis; this.reducer = reducer;
5727 >        }
5728 >        public final Long getRawResult() { return result; }
5729 >        public final void compute() {
5730 >            final ObjectToLong<? super K> transformer;
5731 >            final LongByLongToLong reducer;
5732 >            if ((transformer = this.transformer) != null &&
5733 >                (reducer = this.reducer) != null) {
5734 >                long r = this.basis;
5735 >                for (int i = baseIndex, f, h; batch > 0 &&
5736 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5737 >                    addToPendingCount(1);
5738 >                    (rights = new MapReduceKeysToLongTask<K,V>
5739 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5740 >                      rights, transformer, r, reducer)).fork();
5741 >                }
5742 >                for (Node<K,V> p; (p = advance()) != null; )
5743 >                    r = reducer.apply(r, transformer.apply(p.key));
5744 >                result = r;
5745 >                CountedCompleter<?> c;
5746 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5747 >                    @SuppressWarnings("unchecked") MapReduceKeysToLongTask<K,V>
5748 >                        t = (MapReduceKeysToLongTask<K,V>)c,
5749 >                        s = t.rights;
5750 >                    while (s != null) {
5751 >                        t.result = reducer.apply(t.result, s.result);
5752 >                        s = t.rights = s.nextRight;
5753 >                    }
5754 >                }
5755 >            }
5756 >        }
5757 >    }
5758 >
5759 >    @SuppressWarnings("serial")
5760 >    static final class MapReduceValuesToLongTask<K,V>
5761 >        extends BulkTask<K,V,Long> {
5762 >        final ObjectToLong<? super V> transformer;
5763 >        final LongByLongToLong reducer;
5764 >        final long basis;
5765 >        long result;
5766 >        MapReduceValuesToLongTask<K,V> rights, nextRight;
5767 >        MapReduceValuesToLongTask
5768 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5769 >             MapReduceValuesToLongTask<K,V> nextRight,
5770 >             ObjectToLong<? super V> transformer,
5771 >             long basis,
5772 >             LongByLongToLong reducer) {
5773 >            super(p, b, i, f, t); this.nextRight = nextRight;
5774 >            this.transformer = transformer;
5775 >            this.basis = basis; this.reducer = reducer;
5776 >        }
5777 >        public final Long getRawResult() { return result; }
5778 >        public final void compute() {
5779 >            final ObjectToLong<? super V> transformer;
5780 >            final LongByLongToLong reducer;
5781 >            if ((transformer = this.transformer) != null &&
5782 >                (reducer = this.reducer) != null) {
5783 >                long r = this.basis;
5784 >                for (int i = baseIndex, f, h; batch > 0 &&
5785 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5786 >                    addToPendingCount(1);
5787 >                    (rights = new MapReduceValuesToLongTask<K,V>
5788 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5789 >                      rights, transformer, r, reducer)).fork();
5790 >                }
5791 >                for (Node<K,V> p; (p = advance()) != null; )
5792 >                    r = reducer.apply(r, transformer.apply(p.val));
5793 >                result = r;
5794 >                CountedCompleter<?> c;
5795 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5796 >                    @SuppressWarnings("unchecked") MapReduceValuesToLongTask<K,V>
5797 >                        t = (MapReduceValuesToLongTask<K,V>)c,
5798 >                        s = t.rights;
5799 >                    while (s != null) {
5800 >                        t.result = reducer.apply(t.result, s.result);
5801 >                        s = t.rights = s.nextRight;
5802 >                    }
5803 >                }
5804 >            }
5805 >        }
5806 >    }
5807 >
5808 >    @SuppressWarnings("serial")
5809 >    static final class MapReduceEntriesToLongTask<K,V>
5810 >        extends BulkTask<K,V,Long> {
5811 >        final ObjectToLong<Map.Entry<K,V>> transformer;
5812 >        final LongByLongToLong reducer;
5813 >        final long basis;
5814 >        long result;
5815 >        MapReduceEntriesToLongTask<K,V> rights, nextRight;
5816 >        MapReduceEntriesToLongTask
5817 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5818 >             MapReduceEntriesToLongTask<K,V> nextRight,
5819 >             ObjectToLong<Map.Entry<K,V>> transformer,
5820 >             long basis,
5821 >             LongByLongToLong reducer) {
5822 >            super(p, b, i, f, t); this.nextRight = nextRight;
5823 >            this.transformer = transformer;
5824 >            this.basis = basis; this.reducer = reducer;
5825 >        }
5826 >        public final Long getRawResult() { return result; }
5827 >        public final void compute() {
5828 >            final ObjectToLong<Map.Entry<K,V>> transformer;
5829 >            final LongByLongToLong reducer;
5830 >            if ((transformer = this.transformer) != null &&
5831 >                (reducer = this.reducer) != null) {
5832 >                long r = this.basis;
5833 >                for (int i = baseIndex, f, h; batch > 0 &&
5834 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5835 >                    addToPendingCount(1);
5836 >                    (rights = new MapReduceEntriesToLongTask<K,V>
5837 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5838 >                      rights, transformer, r, reducer)).fork();
5839 >                }
5840 >                for (Node<K,V> p; (p = advance()) != null; )
5841 >                    r = reducer.apply(r, transformer.apply(p));
5842 >                result = r;
5843 >                CountedCompleter<?> c;
5844 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5845 >                    @SuppressWarnings("unchecked") MapReduceEntriesToLongTask<K,V>
5846 >                        t = (MapReduceEntriesToLongTask<K,V>)c,
5847 >                        s = t.rights;
5848 >                    while (s != null) {
5849 >                        t.result = reducer.apply(t.result, s.result);
5850 >                        s = t.rights = s.nextRight;
5851 >                    }
5852 >                }
5853 >            }
5854 >        }
5855 >    }
5856 >
5857 >    @SuppressWarnings("serial")
5858 >    static final class MapReduceMappingsToLongTask<K,V>
5859 >        extends BulkTask<K,V,Long> {
5860 >        final ObjectByObjectToLong<? super K, ? super V> transformer;
5861 >        final LongByLongToLong reducer;
5862 >        final long basis;
5863 >        long result;
5864 >        MapReduceMappingsToLongTask<K,V> rights, nextRight;
5865 >        MapReduceMappingsToLongTask
5866 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5867 >             MapReduceMappingsToLongTask<K,V> nextRight,
5868 >             ObjectByObjectToLong<? super K, ? super V> transformer,
5869 >             long basis,
5870 >             LongByLongToLong reducer) {
5871 >            super(p, b, i, f, t); this.nextRight = nextRight;
5872 >            this.transformer = transformer;
5873 >            this.basis = basis; this.reducer = reducer;
5874 >        }
5875 >        public final Long getRawResult() { return result; }
5876 >        public final void compute() {
5877 >            final ObjectByObjectToLong<? super K, ? super V> transformer;
5878 >            final LongByLongToLong reducer;
5879 >            if ((transformer = this.transformer) != null &&
5880 >                (reducer = this.reducer) != null) {
5881 >                long r = this.basis;
5882 >                for (int i = baseIndex, f, h; batch > 0 &&
5883 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5884 >                    addToPendingCount(1);
5885 >                    (rights = new MapReduceMappingsToLongTask<K,V>
5886 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5887 >                      rights, transformer, r, reducer)).fork();
5888 >                }
5889 >                for (Node<K,V> p; (p = advance()) != null; )
5890 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
5891 >                result = r;
5892 >                CountedCompleter<?> c;
5893 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5894 >                    @SuppressWarnings("unchecked") MapReduceMappingsToLongTask<K,V>
5895 >                        t = (MapReduceMappingsToLongTask<K,V>)c,
5896 >                        s = t.rights;
5897 >                    while (s != null) {
5898 >                        t.result = reducer.apply(t.result, s.result);
5899 >                        s = t.rights = s.nextRight;
5900 >                    }
5901 >                }
5902 >            }
5903 >        }
5904 >    }
5905 >
5906 >    @SuppressWarnings("serial")
5907 >    static final class MapReduceKeysToIntTask<K,V>
5908 >        extends BulkTask<K,V,Integer> {
5909 >        final ObjectToInt<? super K> transformer;
5910 >        final IntByIntToInt reducer;
5911 >        final int basis;
5912 >        int result;
5913 >        MapReduceKeysToIntTask<K,V> rights, nextRight;
5914 >        MapReduceKeysToIntTask
5915 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5916 >             MapReduceKeysToIntTask<K,V> nextRight,
5917 >             ObjectToInt<? super K> transformer,
5918 >             int basis,
5919 >             IntByIntToInt reducer) {
5920 >            super(p, b, i, f, t); this.nextRight = nextRight;
5921 >            this.transformer = transformer;
5922 >            this.basis = basis; this.reducer = reducer;
5923 >        }
5924 >        public final Integer getRawResult() { return result; }
5925 >        public final void compute() {
5926 >            final ObjectToInt<? super K> transformer;
5927 >            final IntByIntToInt reducer;
5928 >            if ((transformer = this.transformer) != null &&
5929 >                (reducer = this.reducer) != null) {
5930 >                int r = this.basis;
5931 >                for (int i = baseIndex, f, h; batch > 0 &&
5932 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5933 >                    addToPendingCount(1);
5934 >                    (rights = new MapReduceKeysToIntTask<K,V>
5935 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5936 >                      rights, transformer, r, reducer)).fork();
5937 >                }
5938 >                for (Node<K,V> p; (p = advance()) != null; )
5939 >                    r = reducer.apply(r, transformer.apply(p.key));
5940 >                result = r;
5941 >                CountedCompleter<?> c;
5942 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5943 >                    @SuppressWarnings("unchecked") MapReduceKeysToIntTask<K,V>
5944 >                        t = (MapReduceKeysToIntTask<K,V>)c,
5945 >                        s = t.rights;
5946 >                    while (s != null) {
5947 >                        t.result = reducer.apply(t.result, s.result);
5948 >                        s = t.rights = s.nextRight;
5949 >                    }
5950 >                }
5951 >            }
5952 >        }
5953 >    }
5954 >
5955 >    @SuppressWarnings("serial")
5956 >    static final class MapReduceValuesToIntTask<K,V>
5957 >        extends BulkTask<K,V,Integer> {
5958 >        final ObjectToInt<? super V> transformer;
5959 >        final IntByIntToInt reducer;
5960 >        final int basis;
5961 >        int result;
5962 >        MapReduceValuesToIntTask<K,V> rights, nextRight;
5963 >        MapReduceValuesToIntTask
5964 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5965 >             MapReduceValuesToIntTask<K,V> nextRight,
5966 >             ObjectToInt<? super V> transformer,
5967 >             int basis,
5968 >             IntByIntToInt reducer) {
5969 >            super(p, b, i, f, t); this.nextRight = nextRight;
5970 >            this.transformer = transformer;
5971 >            this.basis = basis; this.reducer = reducer;
5972 >        }
5973 >        public final Integer getRawResult() { return result; }
5974 >        public final void compute() {
5975 >            final ObjectToInt<? super V> transformer;
5976 >            final IntByIntToInt reducer;
5977 >            if ((transformer = this.transformer) != null &&
5978 >                (reducer = this.reducer) != null) {
5979 >                int r = this.basis;
5980 >                for (int i = baseIndex, f, h; batch > 0 &&
5981 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
5982 >                    addToPendingCount(1);
5983 >                    (rights = new MapReduceValuesToIntTask<K,V>
5984 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
5985 >                      rights, transformer, r, reducer)).fork();
5986 >                }
5987 >                for (Node<K,V> p; (p = advance()) != null; )
5988 >                    r = reducer.apply(r, transformer.apply(p.val));
5989 >                result = r;
5990 >                CountedCompleter<?> c;
5991 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
5992 >                    @SuppressWarnings("unchecked") MapReduceValuesToIntTask<K,V>
5993 >                        t = (MapReduceValuesToIntTask<K,V>)c,
5994 >                        s = t.rights;
5995 >                    while (s != null) {
5996 >                        t.result = reducer.apply(t.result, s.result);
5997 >                        s = t.rights = s.nextRight;
5998 >                    }
5999 >                }
6000 >            }
6001 >        }
6002 >    }
6003 >
6004 >    @SuppressWarnings("serial")
6005 >    static final class MapReduceEntriesToIntTask<K,V>
6006 >        extends BulkTask<K,V,Integer> {
6007 >        final ObjectToInt<Map.Entry<K,V>> transformer;
6008 >        final IntByIntToInt reducer;
6009 >        final int basis;
6010 >        int result;
6011 >        MapReduceEntriesToIntTask<K,V> rights, nextRight;
6012 >        MapReduceEntriesToIntTask
6013 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6014 >             MapReduceEntriesToIntTask<K,V> nextRight,
6015 >             ObjectToInt<Map.Entry<K,V>> transformer,
6016 >             int basis,
6017 >             IntByIntToInt reducer) {
6018 >            super(p, b, i, f, t); this.nextRight = nextRight;
6019 >            this.transformer = transformer;
6020 >            this.basis = basis; this.reducer = reducer;
6021 >        }
6022 >        public final Integer getRawResult() { return result; }
6023 >        public final void compute() {
6024 >            final ObjectToInt<Map.Entry<K,V>> transformer;
6025 >            final IntByIntToInt reducer;
6026 >            if ((transformer = this.transformer) != null &&
6027 >                (reducer = this.reducer) != null) {
6028 >                int r = this.basis;
6029 >                for (int i = baseIndex, f, h; batch > 0 &&
6030 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
6031 >                    addToPendingCount(1);
6032 >                    (rights = new MapReduceEntriesToIntTask<K,V>
6033 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
6034 >                      rights, transformer, r, reducer)).fork();
6035 >                }
6036 >                for (Node<K,V> p; (p = advance()) != null; )
6037 >                    r = reducer.apply(r, transformer.apply(p));
6038 >                result = r;
6039 >                CountedCompleter<?> c;
6040 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
6041 >                    @SuppressWarnings("unchecked") MapReduceEntriesToIntTask<K,V>
6042 >                        t = (MapReduceEntriesToIntTask<K,V>)c,
6043 >                        s = t.rights;
6044 >                    while (s != null) {
6045 >                        t.result = reducer.apply(t.result, s.result);
6046 >                        s = t.rights = s.nextRight;
6047 >                    }
6048 >                }
6049 >            }
6050 >        }
6051 >    }
6052 >
6053 >    @SuppressWarnings("serial")
6054 >    static final class MapReduceMappingsToIntTask<K,V>
6055 >        extends BulkTask<K,V,Integer> {
6056 >        final ObjectByObjectToInt<? super K, ? super V> transformer;
6057 >        final IntByIntToInt reducer;
6058 >        final int basis;
6059 >        int result;
6060 >        MapReduceMappingsToIntTask<K,V> rights, nextRight;
6061 >        MapReduceMappingsToIntTask
6062 >            (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6063 >             MapReduceMappingsToIntTask<K,V> nextRight,
6064 >             ObjectByObjectToInt<? super K, ? super V> transformer,
6065 >             int basis,
6066 >             IntByIntToInt reducer) {
6067 >            super(p, b, i, f, t); this.nextRight = nextRight;
6068 >            this.transformer = transformer;
6069 >            this.basis = basis; this.reducer = reducer;
6070 >        }
6071 >        public final Integer getRawResult() { return result; }
6072 >        public final void compute() {
6073 >            final ObjectByObjectToInt<? super K, ? super V> transformer;
6074 >            final IntByIntToInt reducer;
6075 >            if ((transformer = this.transformer) != null &&
6076 >                (reducer = this.reducer) != null) {
6077 >                int r = this.basis;
6078 >                for (int i = baseIndex, f, h; batch > 0 &&
6079 >                         (h = ((f = baseLimit) + i) >>> 1) > i;) {
6080 >                    addToPendingCount(1);
6081 >                    (rights = new MapReduceMappingsToIntTask<K,V>
6082 >                     (this, batch >>>= 1, baseLimit = h, f, tab,
6083 >                      rights, transformer, r, reducer)).fork();
6084 >                }
6085 >                for (Node<K,V> p; (p = advance()) != null; )
6086 >                    r = reducer.apply(r, transformer.apply(p.key, p.val));
6087 >                result = r;
6088 >                CountedCompleter<?> c;
6089 >                for (c = firstComplete(); c != null; c = c.nextComplete()) {
6090 >                    @SuppressWarnings("unchecked") MapReduceMappingsToIntTask<K,V>
6091 >                        t = (MapReduceMappingsToIntTask<K,V>)c,
6092 >                        s = t.rights;
6093 >                    while (s != null) {
6094 >                        t.result = reducer.apply(t.result, s.result);
6095 >                        s = t.rights = s.nextRight;
6096 >                    }
6097 >                }
6098 >            }
6099 >        }
6100 >    }
6101 >
6102 >    /* ---------------- Counters -------------- */
6103 >
6104 >    // Adapted from LongAdder and Striped64.
6105 >    // See their internal docs for explanation.
6106 >
6107 >    // A padded cell for distributing counts
6108 >    static final class CounterCell {
6109 >        volatile long p0, p1, p2, p3, p4, p5, p6;
6110 >        volatile long value;
6111 >        volatile long q0, q1, q2, q3, q4, q5, q6;
6112 >        CounterCell(long x) { value = x; }
6113      }
6114  
6115      /**
6116 <     * Saves the state of the {@code ConcurrentHashMapV8} instance to a
6117 <     * stream (i.e., serializes it).
6118 <     * @param s the stream
2330 <     * @serialData
2331 <     * the key (Object) and value (Object)
2332 <     * for each key-value mapping, followed by a null pair.
2333 <     * The key-value mappings are emitted in no particular order.
6116 >     * Holder for the thread-local hash code determining which
6117 >     * CounterCell to use. The code is initialized via the
6118 >     * counterHashCodeGenerator, but may be moved upon collisions.
6119       */
6120 <    @SuppressWarnings("unchecked")
6121 <    private void writeObject(java.io.ObjectOutputStream s)
2337 <            throws java.io.IOException {
2338 <        if (segments == null) { // for serialization compatibility
2339 <            segments = (Segment<K,V>[])
2340 <                new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
2341 <            for (int i = 0; i < segments.length; ++i)
2342 <                segments[i] = new Segment<K,V>(LOAD_FACTOR);
2343 <        }
2344 <        s.defaultWriteObject();
2345 <        InternalIterator it = new InternalIterator(table);
2346 <        while (it.next != null) {
2347 <            s.writeObject(it.nextKey);
2348 <            s.writeObject(it.nextVal);
2349 <            it.advance();
2350 <        }
2351 <        s.writeObject(null);
2352 <        s.writeObject(null);
2353 <        segments = null; // throw away
6120 >    static final class CounterHashCode {
6121 >        int code;
6122      }
6123  
6124      /**
6125 <     * Reconstitutes the instance from a stream (that is, deserializes it).
2358 <     * @param s the stream
6125 >     * Generates initial value for per-thread CounterHashCodes.
6126       */
6127 <    @SuppressWarnings("unchecked")
2361 <    private void readObject(java.io.ObjectInputStream s)
2362 <            throws java.io.IOException, ClassNotFoundException {
2363 <        s.defaultReadObject();
2364 <        this.segments = null; // unneeded
2365 <        // initialize transient final field
2366 <        UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
6127 >    static final AtomicInteger counterHashCodeGenerator = new AtomicInteger();
6128  
6129 <        // Create all nodes, then place in table once size is known
6130 <        long size = 0L;
6131 <        Node p = null;
6132 <        for (;;) {
6133 <            K k = (K) s.readObject();
6134 <            V v = (V) s.readObject();
6135 <            if (k != null && v != null) {
6136 <                p = new Node(spread(k.hashCode()), k, v, p);
6137 <                ++size;
6129 >    /**
6130 >     * Increment for counterHashCodeGenerator. See class ThreadLocal
6131 >     * for explanation.
6132 >     */
6133 >    static final int SEED_INCREMENT = 0x61c88647;
6134 >
6135 >    /**
6136 >     * Per-thread counter hash codes. Shared across all instances.
6137 >     */
6138 >    static final ThreadLocal<CounterHashCode> threadCounterHashCode =
6139 >        new ThreadLocal<CounterHashCode>();
6140 >
6141 >
6142 >    final long sumCount() {
6143 >        CounterCell[] as = counterCells; CounterCell a;
6144 >        long sum = baseCount;
6145 >        if (as != null) {
6146 >            for (int i = 0; i < as.length; ++i) {
6147 >                if ((a = as[i]) != null)
6148 >                    sum += a.value;
6149              }
2378            else
2379                break;
6150          }
6151 <        if (p != null) {
6152 <            boolean init = false;
6153 <            int n;
6154 <            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
6155 <                n = MAXIMUM_CAPACITY;
6156 <            else {
6157 <                int sz = (int)size;
6158 <                n = tableSizeFor(sz + (sz >>> 1) + 1);
6159 <            }
6160 <            int sc = sizeCtl;
6161 <            if (n > sc &&
6162 <                UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
6163 <                try {
6164 <                    if (table == null) {
6165 <                        init = true;
6166 <                        Node[] tab = new Node[n];
6167 <                        int mask = n - 1;
6168 <                        while (p != null) {
6169 <                            int j = p.hash & mask;
6170 <                            Node next = p.next;
6171 <                            p.next = tabAt(tab, j);
6172 <                            setTabAt(tab, j, p);
6173 <                            p = next;
6151 >        return sum;
6152 >    }
6153 >
6154 >    // See LongAdder version for explanation
6155 >    private final void fullAddCount(long x, CounterHashCode hc,
6156 >                                    boolean wasUncontended) {
6157 >        int h;
6158 >        if (hc == null) {
6159 >            hc = new CounterHashCode();
6160 >            int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT);
6161 >            h = hc.code = (s == 0) ? 1 : s; // Avoid zero
6162 >            threadCounterHashCode.set(hc);
6163 >        }
6164 >        else
6165 >            h = hc.code;
6166 >        boolean collide = false;                // True if last slot nonempty
6167 >        for (;;) {
6168 >            CounterCell[] as; CounterCell a; int n; long v;
6169 >            if ((as = counterCells) != null && (n = as.length) > 0) {
6170 >                if ((a = as[(n - 1) & h]) == null) {
6171 >                    if (cellsBusy == 0) {            // Try to attach new Cell
6172 >                        CounterCell r = new CounterCell(x); // Optimistic create
6173 >                        if (cellsBusy == 0 &&
6174 >                            U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
6175 >                            boolean created = false;
6176 >                            try {               // Recheck under lock
6177 >                                CounterCell[] rs; int m, j;
6178 >                                if ((rs = counterCells) != null &&
6179 >                                    (m = rs.length) > 0 &&
6180 >                                    rs[j = (m - 1) & h] == null) {
6181 >                                    rs[j] = r;
6182 >                                    created = true;
6183 >                                }
6184 >                            } finally {
6185 >                                cellsBusy = 0;
6186 >                            }
6187 >                            if (created)
6188 >                                break;
6189 >                            continue;           // Slot is now non-empty
6190                          }
2405                        table = tab;
2406                        counter.add(size);
2407                        sc = n - (n >>> 2);
6191                      }
6192 <                } finally {
2410 <                    sizeCtl = sc;
6192 >                    collide = false;
6193                  }
6194 <            }
6195 <            if (!init) { // Can only happen if unsafely published.
6196 <                while (p != null) {
6197 <                    internalPut(p.key, p.val);
6198 <                    p = p.next;
6194 >                else if (!wasUncontended)       // CAS already known to fail
6195 >                    wasUncontended = true;      // Continue after rehash
6196 >                else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
6197 >                    break;
6198 >                else if (counterCells != as || n >= NCPU)
6199 >                    collide = false;            // At max size or stale
6200 >                else if (!collide)
6201 >                    collide = true;
6202 >                else if (cellsBusy == 0 &&
6203 >                         U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
6204 >                    try {
6205 >                        if (counterCells == as) {// Expand table unless stale
6206 >                            CounterCell[] rs = new CounterCell[n << 1];
6207 >                            for (int i = 0; i < n; ++i)
6208 >                                rs[i] = as[i];
6209 >                            counterCells = rs;
6210 >                        }
6211 >                    } finally {
6212 >                        cellsBusy = 0;
6213 >                    }
6214 >                    collide = false;
6215 >                    continue;                   // Retry with expanded table
6216                  }
6217 +                h ^= h << 13;                   // Rehash
6218 +                h ^= h >>> 17;
6219 +                h ^= h << 5;
6220 +            }
6221 +            else if (cellsBusy == 0 && counterCells == as &&
6222 +                     U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
6223 +                boolean init = false;
6224 +                try {                           // Initialize table
6225 +                    if (counterCells == as) {
6226 +                        CounterCell[] rs = new CounterCell[2];
6227 +                        rs[h & 1] = new CounterCell(x);
6228 +                        counterCells = rs;
6229 +                        init = true;
6230 +                    }
6231 +                } finally {
6232 +                    cellsBusy = 0;
6233 +                }
6234 +                if (init)
6235 +                    break;
6236              }
6237 +            else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
6238 +                break;                          // Fall back on using base
6239          }
6240 +        hc.code = h;                            // Record index for next time
6241      }
6242  
6243      // Unsafe mechanics
6244 <    private static final sun.misc.Unsafe UNSAFE;
6245 <    private static final long counterOffset;
6246 <    private static final long sizeCtlOffset;
6244 >    private static final sun.misc.Unsafe U;
6245 >    private static final long SIZECTL;
6246 >    private static final long TRANSFERINDEX;
6247 >    private static final long BASECOUNT;
6248 >    private static final long CELLSBUSY;
6249 >    private static final long CELLVALUE;
6250      private static final long ABASE;
6251      private static final int ASHIFT;
6252  
6253      static {
2430        int ss;
6254          try {
6255 <            UNSAFE = getUnsafe();
6255 >            U = getUnsafe();
6256              Class<?> k = ConcurrentHashMapV8.class;
6257 <            counterOffset = UNSAFE.objectFieldOffset
2435 <                (k.getDeclaredField("counter"));
2436 <            sizeCtlOffset = UNSAFE.objectFieldOffset
6257 >            SIZECTL = U.objectFieldOffset
6258                  (k.getDeclaredField("sizeCtl"));
6259 <            Class<?> sc = Node[].class;
6260 <            ABASE = UNSAFE.arrayBaseOffset(sc);
6261 <            ss = UNSAFE.arrayIndexScale(sc);
6259 >            TRANSFERINDEX = U.objectFieldOffset
6260 >                (k.getDeclaredField("transferIndex"));
6261 >            BASECOUNT = U.objectFieldOffset
6262 >                (k.getDeclaredField("baseCount"));
6263 >            CELLSBUSY = U.objectFieldOffset
6264 >                (k.getDeclaredField("cellsBusy"));
6265 >            Class<?> ck = CounterCell.class;
6266 >            CELLVALUE = U.objectFieldOffset
6267 >                (ck.getDeclaredField("value"));
6268 >            Class<?> ak = Node[].class;
6269 >            ABASE = U.arrayBaseOffset(ak);
6270 >            int scale = U.arrayIndexScale(ak);
6271 >            if ((scale & (scale - 1)) != 0)
6272 >                throw new Error("data type scale not a power of two");
6273 >            ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6274          } catch (Exception e) {
6275              throw new Error(e);
6276          }
2444        if ((ss & (ss-1)) != 0)
2445            throw new Error("data type scale not a power of two");
2446        ASHIFT = 31 - Integer.numberOfLeadingZeros(ss);
6277      }
6278  
6279      /**
# Line 2456 | Line 6286 | public class ConcurrentHashMapV8<K, V>
6286      private static sun.misc.Unsafe getUnsafe() {
6287          try {
6288              return sun.misc.Unsafe.getUnsafe();
6289 <        } catch (SecurityException se) {
6290 <            try {
6291 <                return java.security.AccessController.doPrivileged
6292 <                    (new java.security
6293 <                     .PrivilegedExceptionAction<sun.misc.Unsafe>() {
6294 <                        public sun.misc.Unsafe run() throws Exception {
6295 <                            java.lang.reflect.Field f = sun.misc
6296 <                                .Unsafe.class.getDeclaredField("theUnsafe");
6297 <                            f.setAccessible(true);
6298 <                            return (sun.misc.Unsafe) f.get(null);
6299 <                        }});
6300 <            } catch (java.security.PrivilegedActionException e) {
6301 <                throw new RuntimeException("Could not initialize intrinsics",
6302 <                                           e.getCause());
6303 <            }
6289 >        } catch (SecurityException tryReflectionInstead) {}
6290 >        try {
6291 >            return java.security.AccessController.doPrivileged
6292 >            (new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
6293 >                public sun.misc.Unsafe run() throws Exception {
6294 >                    Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
6295 >                    for (java.lang.reflect.Field f : k.getDeclaredFields()) {
6296 >                        f.setAccessible(true);
6297 >                        Object x = f.get(null);
6298 >                        if (k.isInstance(x))
6299 >                            return k.cast(x);
6300 >                    }
6301 >                    throw new NoSuchFieldError("the Unsafe");
6302 >                }});
6303 >        } catch (java.security.PrivilegedActionException e) {
6304 >            throw new RuntimeException("Could not initialize intrinsics",
6305 >                                       e.getCause());
6306          }
6307      }
2476
6308   }

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