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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.7 by jsr166, Tue Aug 30 13:41:59 2011 UTC vs.
Revision 1.61 by dl, Thu Sep 13 10:41:37 2012 UTC

# Line 6 | Line 6
6  
7   package jsr166e;
8   import jsr166e.LongAdder;
9 + import jsr166e.ForkJoinPool;
10 + import jsr166e.ForkJoinTask;
11 +
12 + import java.util.Comparator;
13 + import java.util.Arrays;
14   import java.util.Map;
15   import java.util.Set;
16   import java.util.Collection;
# Line 19 | Line 24 | import java.util.Enumeration;
24   import java.util.ConcurrentModificationException;
25   import java.util.NoSuchElementException;
26   import java.util.concurrent.ConcurrentMap;
27 + import java.util.concurrent.ThreadLocalRandom;
28 + import java.util.concurrent.locks.LockSupport;
29 + import java.util.concurrent.locks.AbstractQueuedSynchronizer;
30 + import java.util.concurrent.atomic.AtomicReference;
31 +
32   import java.io.Serializable;
33  
34   /**
# Line 37 | Line 47 | import java.io.Serializable;
47   * block, so may overlap with update operations (including {@code put}
48   * and {@code remove}). Retrievals reflect the results of the most
49   * recently <em>completed</em> update operations holding upon their
50 < * onset.  For aggregate operations such as {@code putAll} and {@code
51 < * clear}, concurrent retrievals may reflect insertion or removal of
52 < * only some entries.  Similarly, Iterators and Enumerations return
53 < * elements reflecting the state of the hash table at some point at or
54 < * since the creation of the iterator/enumeration.  They do
55 < * <em>not</em> throw {@link ConcurrentModificationException}.
56 < * However, iterators are designed to be used by only one thread at a
57 < * time.  Bear in mind that the results of aggregate status methods
58 < * including {@code size}, {@code isEmpty}, and {@code containsValue}
59 < * are typically useful only when a map is not undergoing concurrent
60 < * updates in other threads.  Otherwise the results of these methods
61 < * reflect transient states that may be adequate for monitoring
62 < * purposes, but not for program control.
50 > * onset. (More formally, an update operation for a given key bears a
51 > * <em>happens-before</em> relation with any (non-null) retrieval for
52 > * that key reporting the updated value.)  For aggregate operations
53 > * such as {@code putAll} and {@code clear}, concurrent retrievals may
54 > * reflect insertion or removal of only some entries.  Similarly,
55 > * Iterators and Enumerations return elements reflecting the state of
56 > * the hash table at some point at or since the creation of the
57 > * iterator/enumeration.  They do <em>not</em> throw {@link
58 > * ConcurrentModificationException}.  However, iterators are designed
59 > * to be used by only one thread at a time.  Bear in mind that the
60 > * results of aggregate status methods including {@code size}, {@code
61 > * isEmpty}, and {@code containsValue} are typically useful only when
62 > * a map is not undergoing concurrent updates in other threads.
63 > * Otherwise the results of these methods reflect transient states
64 > * that may be adequate for monitoring or estimation purposes, but not
65 > * for program control.
66   *
67 < * <p> Resizing this or any other kind of hash table is a relatively
68 < * slow operation, so, when possible, it is a good idea to provide
69 < * estimates of expected table sizes in constructors. Also, for
70 < * compatibility with previous versions of this class, constructors
71 < * may optionally specify an expected {@code concurrencyLevel} as an
72 < * additional hint for internal sizing.
67 > * <p> The table is dynamically expanded when there are too many
68 > * collisions (i.e., keys that have distinct hash codes but fall into
69 > * the same slot modulo the table size), with the expected average
70 > * effect of maintaining roughly two bins per mapping (corresponding
71 > * to a 0.75 load factor threshold for resizing). There may be much
72 > * variance around this average as mappings are added and removed, but
73 > * overall, this maintains a commonly accepted time/space tradeoff for
74 > * hash tables.  However, resizing this or any other kind of hash
75 > * table may be a relatively slow operation. When possible, it is a
76 > * good idea to provide a size estimate as an optional {@code
77 > * initialCapacity} constructor argument. An additional optional
78 > * {@code loadFactor} constructor argument provides a further means of
79 > * customizing initial table capacity by specifying the table density
80 > * to be used in calculating the amount of space to allocate for the
81 > * given number of elements.  Also, for compatibility with previous
82 > * versions of this class, constructors may optionally specify an
83 > * expected {@code concurrencyLevel} as an additional hint for
84 > * internal sizing.  Note that using many keys with exactly the same
85 > * {@code hashCode()} is a sure way to slow down performance of any
86 > * hash table.
87   *
88   * <p>This class and its views and iterators implement all of the
89   * <em>optional</em> methods of the {@link Map} and {@link Iterator}
# Line 70 | Line 97 | import java.io.Serializable;
97   * Java Collections Framework</a>.
98   *
99   * <p><em>jsr166e note: This class is a candidate replacement for
100 < * java.util.concurrent.ConcurrentHashMap.<em>
100 > * java.util.concurrent.ConcurrentHashMap.  During transition, this
101 > * class declares and uses nested functional interfaces with different
102 > * names but the same forms as those expected for JDK8.<em>
103   *
104   * @since 1.5
105   * @author Doug Lea
# Line 78 | Line 107 | import java.io.Serializable;
107   * @param <V> the type of mapped values
108   */
109   public class ConcurrentHashMapV8<K, V>
110 <        implements ConcurrentMap<K, V>, Serializable {
110 >    implements ConcurrentMap<K, V>, Serializable {
111      private static final long serialVersionUID = 7249069246763182397L;
112  
113      /**
114 <     * A function computing a mapping from the given key to a value,
115 <     *  or <code>null</code> if there is no mapping. This is a
116 <     * place-holder for an upcoming JDK8 interface.
117 <     */
118 <    public static interface MappingFunction<K, V> {
119 <        /**
120 <         * Returns a value for the given key, or null if there is no
121 <         * mapping. If this function throws an (unchecked) exception,
122 <         * the exception is rethrown to its caller, and no mapping is
123 <         * recorded.  Because this function is invoked within
124 <         * atomicity control, the computation should be short and
125 <         * simple. The most common usage is to construct a new object
126 <         * serving as an initial mapped value.
114 >     * A partitionable iterator. A Spliterator can be traversed
115 >     * directly, but can also be partitioned (before traversal) by
116 >     * creating another Spliterator that covers a non-overlapping
117 >     * portion of the elements, and so may be amenable to parallel
118 >     * execution.
119 >     *
120 >     * <p> This interface exports a subset of expected JDK8
121 >     * functionality.
122 >     *
123 >     * <p>Sample usage: Here is one (of the several) ways to compute
124 >     * the sum of the values held in a map using the ForkJoin
125 >     * framework. As illustrated here, Spliterators are well suited to
126 >     * designs in which a task repeatedly splits off half its work
127 >     * into forked subtasks until small enough to process directly,
128 >     * and then joins these subtasks. Variants of this style can also
129 >     * be used in completion-based designs.
130 >     *
131 >     * <pre>
132 >     * {@code ConcurrentHashMapV8<String, Long> m = ...
133 >     * // split as if have 8 * parallelism, for load balance
134 >     * int n = m.size();
135 >     * int p = aForkJoinPool.getParallelism() * 8;
136 >     * int split = (n < p)? n : p;
137 >     * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
138 >     * // ...
139 >     * static class SumValues extends RecursiveTask<Long> {
140 >     *   final Spliterator<Long> s;
141 >     *   final int split;             // split while > 1
142 >     *   final SumValues nextJoin;    // records forked subtasks to join
143 >     *   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
144 >     *     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
145 >     *   }
146 >     *   public Long compute() {
147 >     *     long sum = 0;
148 >     *     SumValues subtasks = null; // fork subtasks
149 >     *     for (int s = split >>> 1; s > 0; s >>>= 1)
150 >     *       (subtasks = new SumValues(s.split(), s, subtasks)).fork();
151 >     *     while (s.hasNext())        // directly process remaining elements
152 >     *       sum += s.next();
153 >     *     for (SumValues t = subtasks; t != null; t = t.nextJoin)
154 >     *       sum += t.join();         // collect subtask results
155 >     *     return sum;
156 >     *   }
157 >     * }
158 >     * }</pre>
159 >     */
160 >    public static interface Spliterator<T> extends Iterator<T> {
161 >        /**
162 >         * Returns a Spliterator covering approximately half of the
163 >         * elements, guaranteed not to overlap with those subsequently
164 >         * returned by this Spliterator.  After invoking this method,
165 >         * the current Spliterator will <em>not</em> produce any of
166 >         * the elements of the returned Spliterator, but the two
167 >         * Spliterators together will produce all of the elements that
168 >         * would have been produced by this Spliterator had this
169 >         * method not been called. The exact number of elements
170 >         * produced by the returned Spliterator is not guaranteed, and
171 >         * may be zero (i.e., with {@code hasNext()} reporting {@code
172 >         * false}) if this Spliterator cannot be further split.
173           *
174 <         * @param key the (non-null) key
175 <         * @return a value, or null if none
174 >         * @return a Spliterator covering approximately half of the
175 >         * elements
176 >         * @throws IllegalStateException if this Spliterator has
177 >         * already commenced traversing elements
178           */
179 <        V map(K key);
179 >        Spliterator<T> split();
180      }
181  
182      /*
# Line 108 | Line 185 | public class ConcurrentHashMapV8<K, V>
185       * The primary design goal of this hash table is to maintain
186       * concurrent readability (typically method get(), but also
187       * iterators and related methods) while minimizing update
188 <     * contention.
188 >     * contention. Secondary goals are to keep space consumption about
189 >     * the same or better than java.util.HashMap, and to support high
190 >     * initial insertion rates on an empty table by many threads.
191       *
192       * Each key-value mapping is held in a Node.  Because Node fields
193       * can contain special values, they are defined using plain Object
194       * types. Similarly in turn, all internal methods that use them
195 <     * work off Object types. All public generic-typed methods relay
196 <     * in/out of these internal methods, supplying casts as needed.
195 >     * work off Object types. And similarly, so do the internal
196 >     * methods of auxiliary iterator and view classes.  All public
197 >     * generic typed methods relay in/out of these internal methods,
198 >     * supplying null-checks and casts as needed. This also allows
199 >     * many of the public methods to be factored into a smaller number
200 >     * of internal methods (although sadly not so for the five
201 >     * variants of put-related operations). The validation-based
202 >     * approach explained below leads to a lot of code sprawl because
203 >     * retry-control precludes factoring into smaller methods.
204       *
205       * The table is lazily initialized to a power-of-two size upon the
206 <     * first insertion.  Each bin in the table contains a (typically
207 <     * short) list of Nodes.  Table accesses require volatile/atomic
208 <     * reads, writes, and CASes.  Because there is no other way to
209 <     * arrange this without adding further indirections, we use
210 <     * intrinsics (sun.misc.Unsafe) operations.  The lists of nodes
211 <     * within bins are always accurately traversable under volatile
212 <     * reads, so long as lookups check hash code and non-nullness of
213 <     * key and value before checking key equality. (All valid hash
214 <     * codes are nonnegative. Negative values are reserved for special
215 <     * forwarding nodes; see below.)
216 <     *
217 <     * A bin may be locked during update (insert, delete, and replace)
218 <     * operations.  We do not want to waste the space required to
219 <     * associate a distinct lock object with each bin, so instead use
220 <     * the first node of a bin list itself as a lock, using builtin
221 <     * "synchronized" locks. These save space and we can live with
222 <     * only plain block-structured lock/unlock operations. Using the
223 <     * first node of a list as a lock does not by itself suffice
224 <     * though: When a node is locked, any update must first validate
225 <     * that it is still the first node, and retry if not. (Because new
226 <     * nodes are always appended to lists, once a node is first in a
227 <     * bin, it remains first until deleted or the bin becomes
228 <     * invalidated.)  However, update operations can and usually do
229 <     * still traverse the bin until the point of update, which helps
230 <     * reduce cache misses on retries.  This is a converse of sorts to
231 <     * the lazy locking technique described by Herlihy & Shavit. If
232 <     * there is no existing node during a put operation, then one can
233 <     * be CAS'ed in (without need for lock except in computeIfAbsent);
234 <     * the CAS serves as validation. This is on average the most
235 <     * common case for put operations -- under random hash codes, the
236 <     * distribution of nodes in bins follows a Poisson distribution
237 <     * (see http://en.wikipedia.org/wiki/Poisson_distribution) with a
238 <     * parameter of 0.5 on average under the default loadFactor of
239 <     * 0.75.  The expected number of locks covering different elements
240 <     * (i.e., bins with 2 or more nodes) is approximately 10% at
241 <     * steady state under default settings.  Lock contention
242 <     * probability for two threads accessing arbitrary distinct
243 <     * elements is, roughly, 1 / (8 * #elements).
244 <     *
245 <     * The table is resized when occupancy exceeds a threshold.  Only
246 <     * a single thread performs the resize (using field "resizing", to
247 <     * arrange exclusion), but the table otherwise remains usable for
248 <     * both reads and updates. Resizing proceeds by transferring bins,
249 <     * one by one, from the table to the next table.  Upon transfer,
250 <     * the old table bin contains only a special forwarding node (with
251 <     * negative hash code ("MOVED")) that contains the next table as
206 >     * first insertion.  Each bin in the table normally contains a
207 >     * list of Nodes (most often, the list has only zero or one Node).
208 >     * Table accesses require volatile/atomic reads, writes, and
209 >     * CASes.  Because there is no other way to arrange this without
210 >     * adding further indirections, we use intrinsics
211 >     * (sun.misc.Unsafe) operations.  The lists of nodes within bins
212 >     * are always accurately traversable under volatile reads, so long
213 >     * as lookups check hash code and non-nullness of value before
214 >     * checking key equality.
215 >     *
216 >     * We use the top two bits of Node hash fields for control
217 >     * purposes -- they are available anyway because of addressing
218 >     * constraints.  As explained further below, these top bits are
219 >     * used as follows:
220 >     *  00 - Normal
221 >     *  01 - Locked
222 >     *  11 - Locked and may have a thread waiting for lock
223 >     *  10 - Node is a forwarding node
224 >     *
225 >     * The lower 30 bits of each Node's hash field contain a
226 >     * transformation of the key's hash code, except for forwarding
227 >     * nodes, for which the lower bits are zero (and so always have
228 >     * hash field == MOVED).
229 >     *
230 >     * Insertion (via put or its variants) of the first node in an
231 >     * empty bin is performed by just CASing it to the bin.  This is
232 >     * by far the most common case for put operations under most
233 >     * key/hash distributions.  Other update operations (insert,
234 >     * delete, and replace) require locks.  We do not want to waste
235 >     * the space required to associate a distinct lock object with
236 >     * each bin, so instead use the first node of a bin list itself as
237 >     * a lock. Blocking support for these locks relies on the builtin
238 >     * "synchronized" monitors.  However, we also need a tryLock
239 >     * construction, so we overlay these by using bits of the Node
240 >     * hash field for lock control (see above), and so normally use
241 >     * builtin monitors only for blocking and signalling using
242 >     * wait/notifyAll constructions. See Node.tryAwaitLock.
243 >     *
244 >     * Using the first node of a list as a lock does not by itself
245 >     * suffice though: When a node is locked, any update must first
246 >     * validate that it is still the first node after locking it, and
247 >     * retry if not. Because new nodes are always appended to lists,
248 >     * once a node is first in a bin, it remains first until deleted
249 >     * or the bin becomes invalidated (upon resizing).  However,
250 >     * operations that only conditionally update may inspect nodes
251 >     * until the point of update. This is a converse of sorts to the
252 >     * lazy locking technique described by Herlihy & Shavit.
253 >     *
254 >     * The main disadvantage of per-bin locks is that other update
255 >     * operations on other nodes in a bin list protected by the same
256 >     * lock can stall, for example when user equals() or mapping
257 >     * functions take a long time.  However, statistically, under
258 >     * random hash codes, this is not a common problem.  Ideally, the
259 >     * frequency of nodes in bins follows a Poisson distribution
260 >     * (http://en.wikipedia.org/wiki/Poisson_distribution) with a
261 >     * parameter of about 0.5 on average, given the resizing threshold
262 >     * of 0.75, although with a large variance because of resizing
263 >     * granularity. Ignoring variance, the expected occurrences of
264 >     * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
265 >     * first values are:
266 >     *
267 >     * 0:    0.60653066
268 >     * 1:    0.30326533
269 >     * 2:    0.07581633
270 >     * 3:    0.01263606
271 >     * 4:    0.00157952
272 >     * 5:    0.00015795
273 >     * 6:    0.00001316
274 >     * 7:    0.00000094
275 >     * 8:    0.00000006
276 >     * more: less than 1 in ten million
277 >     *
278 >     * Lock contention probability for two threads accessing distinct
279 >     * elements is roughly 1 / (8 * #elements) under random hashes.
280 >     *
281 >     * Actual hash code distributions encountered in practice
282 >     * sometimes deviate significantly from uniform randomness.  This
283 >     * includes the case when N > (1<<30), so some keys MUST collide.
284 >     * Similarly for dumb or hostile usages in which multiple keys are
285 >     * designed to have identical hash codes. Also, although we guard
286 >     * against the worst effects of this (see method spread), sets of
287 >     * hashes may differ only in bits that do not impact their bin
288 >     * index for a given power-of-two mask.  So we use a secondary
289 >     * strategy that applies when the number of nodes in a bin exceeds
290 >     * a threshold, and at least one of the keys implements
291 >     * Comparable.  These TreeBins use a balanced tree to hold nodes
292 >     * (a specialized form of red-black trees), bounding search time
293 >     * to O(log N).  Each search step in a TreeBin is around twice as
294 >     * slow as in a regular list, but given that N cannot exceed
295 >     * (1<<64) (before running out of addresses) this bounds search
296 >     * steps, lock hold times, etc, to reasonable constants (roughly
297 >     * 100 nodes inspected per operation worst case) so long as keys
298 >     * are Comparable (which is very common -- String, Long, etc).
299 >     * TreeBin nodes (TreeNodes) also maintain the same "next"
300 >     * traversal pointers as regular nodes, so can be traversed in
301 >     * iterators in the same way.
302 >     *
303 >     * The table is resized when occupancy exceeds a percentage
304 >     * threshold (nominally, 0.75, but see below).  Only a single
305 >     * thread performs the resize (using field "sizeCtl", to arrange
306 >     * exclusion), but the table otherwise remains usable for reads
307 >     * and updates. Resizing proceeds by transferring bins, one by
308 >     * one, from the table to the next table.  Because we are using
309 >     * power-of-two expansion, the elements from each bin must either
310 >     * stay at same index, or move with a power of two offset. We
311 >     * eliminate unnecessary node creation by catching cases where old
312 >     * nodes can be reused because their next fields won't change.  On
313 >     * average, only about one-sixth of them need cloning when a table
314 >     * doubles. The nodes they replace will be garbage collectable as
315 >     * soon as they are no longer referenced by any reader thread that
316 >     * may be in the midst of concurrently traversing table.  Upon
317 >     * transfer, the old table bin contains only a special forwarding
318 >     * node (with hash field "MOVED") that contains the next table as
319       * its key. On encountering a forwarding node, access and update
320 <     * operations restart, using the new table. To ensure concurrent
321 <     * readability of traversals, transfers must proceed from the last
322 <     * bin (table.length - 1) up towards the first.  Any traversal
323 <     * starting from the first bin can then arrange to move to the new
324 <     * table for the rest of the traversal without revisiting nodes.
325 <     * This constrains bin transfers to a particular order, and so can
326 <     * block indefinitely waiting for the next lock, and other threads
327 <     * cannot help with the transfer. However, expected stalls are
328 <     * infrequent enough to not warrant the additional overhead and
329 <     * complexity of access and iteration schemes that could admit
330 <     * out-of-order or concurrent bin transfers.
331 <     *
332 <     * A similar traversal scheme (not yet implemented) can apply to
333 <     * partial traversals during partitioned aggregate operations.
334 <     * Also, read-only operations give up if ever forwarded to a null
335 <     * table, which provides support for shutdown-style clearing,
336 <     * which is also not currently implemented.
320 >     * operations restart, using the new table.
321 >     *
322 >     * Each bin transfer requires its bin lock. However, unlike other
323 >     * cases, a transfer can skip a bin if it fails to acquire its
324 >     * lock, and revisit it later (unless it is a TreeBin). Method
325 >     * rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
326 >     * have been skipped because of failure to acquire a lock, and
327 >     * blocks only if none are available (i.e., only very rarely).
328 >     * The transfer operation must also ensure that all accessible
329 >     * bins in both the old and new table are usable by any traversal.
330 >     * When there are no lock acquisition failures, this is arranged
331 >     * simply by proceeding from the last bin (table.length - 1) up
332 >     * towards the first.  Upon seeing a forwarding node, traversals
333 >     * (see class Iter) arrange to move to the new table
334 >     * without revisiting nodes.  However, when any node is skipped
335 >     * during a transfer, all earlier table bins may have become
336 >     * visible, so are initialized with a reverse-forwarding node back
337 >     * to the old table until the new ones are established. (This
338 >     * sometimes requires transiently locking a forwarding node, which
339 >     * is possible under the above encoding.) These more expensive
340 >     * mechanics trigger only when necessary.
341 >     *
342 >     * The traversal scheme also applies to partial traversals of
343 >     * ranges of bins (via an alternate Traverser constructor)
344 >     * to support partitioned aggregate operations.  Also, read-only
345 >     * operations give up if ever forwarded to a null table, which
346 >     * provides support for shutdown-style clearing, which is also not
347 >     * currently implemented.
348 >     *
349 >     * Lazy table initialization minimizes footprint until first use,
350 >     * and also avoids resizings when the first operation is from a
351 >     * putAll, constructor with map argument, or deserialization.
352 >     * These cases attempt to override the initial capacity settings,
353 >     * but harmlessly fail to take effect in cases of races.
354       *
355       * The element count is maintained using a LongAdder, which avoids
356       * contention on updates but can encounter cache thrashing if read
357 <     * too frequently during concurrent updates. To avoid reading so
358 <     * often, resizing is normally attempted only upon adding to a bin
359 <     * already holding two or more nodes. Under the default threshold
360 <     * (0.75), and uniform hash distributions, the probability of this
361 <     * occurring at threshold is around 13%, meaning that only about 1
362 <     * in 8 puts check threshold (and after resizing, many fewer do
363 <     * so). But this approximation has high variance for small table
364 <     * sizes, so we check on any collision for sizes <= 64.  Further,
365 <     * to increase the probability that a resize occurs soon enough, we
366 <     * offset the threshold (see THRESHOLD_OFFSET) by the expected
367 <     * number of puts between checks. This is currently set to 8, in
368 <     * accord with the default load factor. In practice, this is
369 <     * rarely overridden, and in any case is close enough to other
370 <     * plausible values not to waste dynamic probability computation
371 <     * for more precision.
357 >     * too frequently during concurrent access. To avoid reading so
358 >     * often, resizing is attempted either when a bin lock is
359 >     * contended, or upon adding to a bin already holding two or more
360 >     * nodes (checked before adding in the xIfAbsent methods, after
361 >     * adding in others). Under uniform hash distributions, the
362 >     * probability of this occurring at threshold is around 13%,
363 >     * meaning that only about 1 in 8 puts check threshold (and after
364 >     * resizing, many fewer do so). But this approximation has high
365 >     * variance for small table sizes, so we check on any collision
366 >     * for sizes <= 64. The bulk putAll operation further reduces
367 >     * contention by only committing count updates upon these size
368 >     * checks.
369 >     *
370 >     * Maintaining API and serialization compatibility with previous
371 >     * versions of this class introduces several oddities. Mainly: We
372 >     * leave untouched but unused constructor arguments refering to
373 >     * concurrencyLevel. We accept a loadFactor constructor argument,
374 >     * but apply it only to initial table capacity (which is the only
375 >     * time that we can guarantee to honor it.) We also declare an
376 >     * unused "Segment" class that is instantiated in minimal form
377 >     * only when serializing.
378       */
379  
380      /* ---------------- Constants -------------- */
381  
382      /**
383 <     * The smallest allowed table capacity.  Must be a power of 2, at
384 <     * least 2.
383 >     * The largest possible table capacity.  This value must be
384 >     * exactly 1<<30 to stay within Java array allocation and indexing
385 >     * bounds for power of two table sizes, and is further required
386 >     * because the top two bits of 32bit hash fields are used for
387 >     * control purposes.
388       */
389 <    static final int MINIMUM_CAPACITY = 2;
389 >    private static final int MAXIMUM_CAPACITY = 1 << 30;
390  
391      /**
392 <     * The largest allowed table capacity.  Must be a power of 2, at
393 <     * most 1<<30.
392 >     * The default initial table capacity.  Must be a power of 2
393 >     * (i.e., at least 1) and at most MAXIMUM_CAPACITY.
394       */
395 <    static final int MAXIMUM_CAPACITY = 1 << 30;
395 >    private static final int DEFAULT_CAPACITY = 16;
396  
397      /**
398 <     * The default initial table capacity.  Must be a power of 2, at
399 <     * least MINIMUM_CAPACITY and at most MAXIMUM_CAPACITY
398 >     * The largest possible (non-power of two) array size.
399 >     * Needed by toArray and related methods.
400       */
401 <    static final int DEFAULT_CAPACITY = 16;
401 >    static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
402  
403      /**
404 <     * The default load factor for this table, used when not otherwise
405 <     * specified in a constructor.
404 >     * The default concurrency level for this table. Unused but
405 >     * defined for compatibility with previous versions of this class.
406       */
407 <    static final float DEFAULT_LOAD_FACTOR = 0.75f;
407 >    private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
408  
409      /**
410 <     * The default concurrency level for this table. Unused, but
411 <     * defined for compatibility with previous versions of this class.
410 >     * The load factor for this table. Overrides of this value in
411 >     * constructors affect only the initial table capacity.  The
412 >     * actual floating point value isn't normally used -- it is
413 >     * simpler to use expressions such as {@code n - (n >>> 2)} for
414 >     * the associated resizing threshold.
415       */
416 <    static final int DEFAULT_CONCURRENCY_LEVEL = 16;
416 >    private static final float LOAD_FACTOR = 0.75f;
417  
418      /**
419 <     * The count value to offset thresholds to compensate for checking
420 <     * for resizing only when inserting into bins with two or more
421 <     * elements. See above for explanation.
419 >     * The buffer size for skipped bins during transfers. The
420 >     * value is arbitrary but should be large enough to avoid
421 >     * most locking stalls during resizes.
422       */
423 <    static final int THRESHOLD_OFFSET = 8;
423 >    private static final int TRANSFER_BUFFER_SIZE = 32;
424  
425      /**
426 <     * Special node hash value indicating to use table in node.key
427 <     * Must be negative.
426 >     * The bin count threshold for using a tree rather than list for a
427 >     * bin.  The value reflects the approximate break-even point for
428 >     * using tree-based operations.
429 >     */
430 >    private static final int TREE_THRESHOLD = 8;
431 >
432 >    /*
433 >     * Encodings for special uses of Node hash fields. See above for
434 >     * explanation.
435       */
436 <    static final int MOVED = -1;
436 >    static final int MOVED     = 0x80000000; // hash field for forwarding nodes
437 >    static final int LOCKED    = 0x40000000; // set/tested only as a bit
438 >    static final int WAITING   = 0xc0000000; // both bits set/tested together
439 >    static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
440  
441      /* ---------------- Fields -------------- */
442  
443      /**
444       * The array of bins. Lazily initialized upon first insertion.
445 <     * Size is always a power of two. Accessed directly by inner
254 <     * classes.
445 >     * Size is always a power of two. Accessed directly by iterators.
446       */
447      transient volatile Node[] table;
448  
449 <    /** The counter maintaining number of elements. */
449 >    /**
450 >     * The counter maintaining number of elements.
451 >     */
452      private transient final LongAdder counter;
453 <    /** Nonzero when table is being initialized or resized. Updated via CAS. */
454 <    private transient volatile int resizing;
455 <    /** The target load factor for the table. */
456 <    private transient float loadFactor;
457 <    /** The next element count value upon which to resize the table. */
458 <    private transient int threshold;
459 <    /** The initial capacity of the table. */
460 <    private transient int initCap;
453 >
454 >    /**
455 >     * Table initialization and resizing control.  When negative, the
456 >     * table is being initialized or resized. Otherwise, when table is
457 >     * null, holds the initial table size to use upon creation, or 0
458 >     * for default. After initialization, holds the next element count
459 >     * value upon which to resize the table.
460 >     */
461 >    private transient volatile int sizeCtl;
462  
463      // views
464 <    transient Set<K> keySet;
465 <    transient Set<Map.Entry<K,V>> entrySet;
466 <    transient Collection<V> values;
464 >    private transient KeySet<K,V> keySet;
465 >    private transient Values<K,V> values;
466 >    private transient EntrySet<K,V> entrySet;
467  
468      /** For serialization compatibility. Null unless serialized; see below */
469 <    Segment<K,V>[] segments;
469 >    private Segment<K,V>[] segments;
470  
471 <    /**
472 <     * Applies a supplemental hash function to a given hashCode, which
473 <     * defends against poor quality hash functions.  The result must
474 <     * be non-negative, and for reasonable performance must have good
475 <     * avalanche properties; i.e., that each bit of the argument
476 <     * affects each bit (except sign bit) of the result.
471 >    /* ---------------- Table element access -------------- */
472 >
473 >    /*
474 >     * Volatile access methods are used for table elements as well as
475 >     * elements of in-progress next table while resizing.  Uses are
476 >     * null checked by callers, and implicitly bounds-checked, relying
477 >     * on the invariants that tab arrays have non-zero size, and all
478 >     * indices are masked with (tab.length - 1) which is never
479 >     * negative and always less than length. Note that, to be correct
480 >     * wrt arbitrary concurrency errors by users, bounds checks must
481 >     * operate on local variables, which accounts for some odd-looking
482 >     * inline assignments below.
483       */
484 <    private static final int spread(int h) {
485 <        // Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
486 <        h ^= h >>> 16;
487 <        h *= 0x85ebca6b;
488 <        h ^= h >>> 13;
489 <        h *= 0xc2b2ae35;
490 <        return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
484 >
485 >    static final Node tabAt(Node[] tab, int i) { // used by Iter
486 >        return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
487 >    }
488 >
489 >    private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
490 >        return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
491 >    }
492 >
493 >    private static final void setTabAt(Node[] tab, int i, Node v) {
494 >        UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
495      }
496  
497 +    /* ---------------- Nodes -------------- */
498 +
499      /**
500       * Key-value entry. Note that this is never exported out as a
501 <     * user-visible Map.Entry.
501 >     * user-visible Map.Entry (see MapEntry below). Nodes with a hash
502 >     * field of MOVED are special, and do not contain user keys or
503 >     * values.  Otherwise, keys are never null, and null val fields
504 >     * indicate that a node is in the process of being deleted or
505 >     * created. For purposes of read-only access, a key may be read
506 >     * before a val, but can only be used after checking val to be
507 >     * non-null.
508       */
509 <    static final class Node {
510 <        final int hash;
509 >    static class Node {
510 >        volatile int hash;
511          final Object key;
512          volatile Object val;
513          volatile Node next;
# Line 306 | Line 518 | public class ConcurrentHashMapV8<K, V>
518              this.val = val;
519              this.next = next;
520          }
309    }
521  
522 <    /*
523 <     * Volatile access methods are used for table elements as well as
524 <     * elements of in-progress next table while resizing.  Uses in
525 <     * access and update methods are null checked by callers, and
315 <     * implicitly bounds-checked, relying on the invariants that tab
316 <     * arrays have non-zero size, and all indices are masked with
317 <     * (tab.length - 1) which is never negative and always less than
318 <     * length. The "relaxed" non-volatile forms are used only during
319 <     * table initialization. The only other usage is in
320 <     * HashIterator.advance, which performs explicit checks.
321 <     */
522 >        /** CompareAndSet the hash field */
523 >        final boolean casHash(int cmp, int val) {
524 >            return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
525 >        }
526  
527 <    static final Node tabAt(Node[] tab, int i) { // used in HashIterator
528 <        return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
529 <    }
527 >        /** The number of spins before blocking for a lock */
528 >        static final int MAX_SPINS =
529 >            Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
530  
531 <    private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
532 <        return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
533 <    }
531 >        /**
532 >         * Spins a while if LOCKED bit set and this node is the first
533 >         * of its bin, and then sets WAITING bits on hash field and
534 >         * blocks (once) if they are still set.  It is OK for this
535 >         * method to return even if lock is not available upon exit,
536 >         * which enables these simple single-wait mechanics.
537 >         *
538 >         * The corresponding signalling operation is performed within
539 >         * callers: Upon detecting that WAITING has been set when
540 >         * unlocking lock (via a failed CAS from non-waiting LOCKED
541 >         * state), unlockers acquire the sync lock and perform a
542 >         * notifyAll.
543 >         *
544 >         * The initial sanity check on tab and bounds is not currently
545 >         * necessary in the only usages of this method, but enables
546 >         * use in other future contexts.
547 >         */
548 >        final void tryAwaitLock(Node[] tab, int i) {
549 >            if (tab != null && i >= 0 && i < tab.length) { // sanity check
550 >                int r = ThreadLocalRandom.current().nextInt(); // randomize spins
551 >                int spins = MAX_SPINS, h;
552 >                while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
553 >                    if (spins >= 0) {
554 >                        r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
555 >                        if (r >= 0 && --spins == 0)
556 >                            Thread.yield();  // yield before block
557 >                    }
558 >                    else if (casHash(h, h | WAITING)) {
559 >                        synchronized (this) {
560 >                            if (tabAt(tab, i) == this &&
561 >                                (hash & WAITING) == WAITING) {
562 >                                try {
563 >                                    wait();
564 >                                } catch (InterruptedException ie) {
565 >                                    Thread.currentThread().interrupt();
566 >                                }
567 >                            }
568 >                            else
569 >                                notifyAll(); // possibly won race vs signaller
570 >                        }
571 >                        break;
572 >                    }
573 >                }
574 >            }
575 >        }
576  
577 <    private static final void setTabAt(Node[] tab, int i, Node v) {
578 <        UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
579 <    }
577 >        // Unsafe mechanics for casHash
578 >        private static final sun.misc.Unsafe UNSAFE;
579 >        private static final long hashOffset;
580  
581 <    private static final Node relaxedTabAt(Node[] tab, int i) {
582 <        return (Node)UNSAFE.getObject(tab, ((long)i<<ASHIFT)+ABASE);
581 >        static {
582 >            try {
583 >                UNSAFE = getUnsafe();
584 >                Class<?> k = Node.class;
585 >                hashOffset = UNSAFE.objectFieldOffset
586 >                    (k.getDeclaredField("hash"));
587 >            } catch (Exception e) {
588 >                throw new Error(e);
589 >            }
590 >        }
591      }
592  
593 <    private static final void relaxedSetTabAt(Node[] tab, int i, Node v) {
594 <        UNSAFE.putObject(tab, ((long)i<<ASHIFT)+ABASE, v);
593 >    /* ---------------- TreeBins -------------- */
594 >
595 >    /**
596 >     * Nodes for use in TreeBins
597 >     */
598 >    static final class TreeNode extends Node {
599 >        TreeNode parent;  // red-black tree links
600 >        TreeNode left;
601 >        TreeNode right;
602 >        TreeNode prev;    // needed to unlink next upon deletion
603 >        boolean red;
604 >
605 >        TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
606 >            super(hash, key, val, next);
607 >            this.parent = parent;
608 >        }
609      }
610  
611 <    /* ---------------- Access and update operations -------------- */
611 >    /**
612 >     * A specialized form of red-black tree for use in bins
613 >     * whose size exceeds a threshold.
614 >     *
615 >     * TreeBins use a special form of comparison for search and
616 >     * related operations (which is the main reason we cannot use
617 >     * existing collections such as TreeMaps). TreeBins contain
618 >     * Comparable elements, but may contain others, as well as
619 >     * elements that are Comparable but not necessarily Comparable<T>
620 >     * for the same T, so we cannot invoke compareTo among them. To
621 >     * handle this, the tree is ordered primarily by hash value, then
622 >     * by getClass().getName() order, and then by Comparator order
623 >     * among elements of the same class.  On lookup at a node, if
624 >     * elements are not comparable or compare as 0, both left and
625 >     * right children may need to be searched in the case of tied hash
626 >     * values. (This corresponds to the full list search that would be
627 >     * necessary if all elements were non-Comparable and had tied
628 >     * hashes.)  The red-black balancing code is updated from
629 >     * pre-jdk-collections
630 >     * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
631 >     * based in turn on Cormen, Leiserson, and Rivest "Introduction to
632 >     * Algorithms" (CLR).
633 >     *
634 >     * TreeBins also maintain a separate locking discipline than
635 >     * regular bins. Because they are forwarded via special MOVED
636 >     * nodes at bin heads (which can never change once established),
637 >     * we cannot use those nodes as locks. Instead, TreeBin
638 >     * extends AbstractQueuedSynchronizer to support a simple form of
639 >     * read-write lock. For update operations and table validation,
640 >     * the exclusive form of lock behaves in the same way as bin-head
641 >     * locks. However, lookups use shared read-lock mechanics to allow
642 >     * multiple readers in the absence of writers.  Additionally,
643 >     * these lookups do not ever block: While the lock is not
644 >     * available, they proceed along the slow traversal path (via
645 >     * next-pointers) until the lock becomes available or the list is
646 >     * exhausted, whichever comes first. (These cases are not fast,
647 >     * but maximize aggregate expected throughput.)  The AQS mechanics
648 >     * for doing this are straightforward.  The lock state is held as
649 >     * AQS getState().  Read counts are negative; the write count (1)
650 >     * is positive.  There are no signalling preferences among readers
651 >     * and writers. Since we don't need to export full Lock API, we
652 >     * just override the minimal AQS methods and use them directly.
653 >     */
654 >    static final class TreeBin extends AbstractQueuedSynchronizer {
655 >        private static final long serialVersionUID = 2249069246763182397L;
656 >        transient TreeNode root;  // root of tree
657 >        transient TreeNode first; // head of next-pointer list
658  
659 <    /** Implementation for get and containsKey **/
660 <    private final Object internalGet(Object k) {
661 <        int h = spread(k.hashCode());
662 <        Node[] tab = table;
663 <        retry: while (tab != null) {
664 <            Node e = tabAt(tab, (tab.length - 1) & h);
665 <            while (e != null) {
666 <                int eh = e.hash;
667 <                if (eh == h) {
668 <                    Object ek = e.key, ev = e.val;
669 <                    if (ev != null && ek != null && (k == ek || k.equals(ek)))
670 <                        return ev;
671 <                }
672 <                else if (eh < 0) { // bin was moved during resize
673 <                    tab = (Node[])e.key;
674 <                    continue retry;
659 >        /* AQS overrides */
660 >        public final boolean isHeldExclusively() { return getState() > 0; }
661 >        public final boolean tryAcquire(int ignore) {
662 >            if (compareAndSetState(0, 1)) {
663 >                setExclusiveOwnerThread(Thread.currentThread());
664 >                return true;
665 >            }
666 >            return false;
667 >        }
668 >        public final boolean tryRelease(int ignore) {
669 >            setExclusiveOwnerThread(null);
670 >            setState(0);
671 >            return true;
672 >        }
673 >        public final int tryAcquireShared(int ignore) {
674 >            for (int c;;) {
675 >                if ((c = getState()) > 0)
676 >                    return -1;
677 >                if (compareAndSetState(c, c -1))
678 >                    return 1;
679 >            }
680 >        }
681 >        public final boolean tryReleaseShared(int ignore) {
682 >            int c;
683 >            do {} while (!compareAndSetState(c = getState(), c + 1));
684 >            return c == -1;
685 >        }
686 >
687 >        /** From CLR */
688 >        private void rotateLeft(TreeNode p) {
689 >            if (p != null) {
690 >                TreeNode r = p.right, pp, rl;
691 >                if ((rl = p.right = r.left) != null)
692 >                    rl.parent = p;
693 >                if ((pp = r.parent = p.parent) == null)
694 >                    root = r;
695 >                else if (pp.left == p)
696 >                    pp.left = r;
697 >                else
698 >                    pp.right = r;
699 >                r.left = p;
700 >                p.parent = r;
701 >            }
702 >        }
703 >
704 >        /** From CLR */
705 >        private void rotateRight(TreeNode p) {
706 >            if (p != null) {
707 >                TreeNode l = p.left, pp, lr;
708 >                if ((lr = p.left = l.right) != null)
709 >                    lr.parent = p;
710 >                if ((pp = l.parent = p.parent) == null)
711 >                    root = l;
712 >                else if (pp.right == p)
713 >                    pp.right = l;
714 >                else
715 >                    pp.left = l;
716 >                l.right = p;
717 >                p.parent = l;
718 >            }
719 >        }
720 >
721 >        /**
722 >         * Returns the TreeNode (or null if not found) for the given key
723 >         * starting at given root.
724 >         */
725 >        @SuppressWarnings("unchecked") final TreeNode getTreeNode
726 >            (int h, Object k, TreeNode p) {
727 >            Class<?> c = k.getClass();
728 >            while (p != null) {
729 >                int dir, ph;  Object pk; Class<?> pc;
730 >                if ((ph = p.hash) == h) {
731 >                    if ((pk = p.key) == k || k.equals(pk))
732 >                        return p;
733 >                    if (c != (pc = pk.getClass()) ||
734 >                        !(k instanceof Comparable) ||
735 >                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
736 >                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
737 >                        TreeNode r = null, s = null, pl, pr;
738 >                        if (dir >= 0) {
739 >                            if ((pl = p.left) != null && h <= pl.hash)
740 >                                s = pl;
741 >                        }
742 >                        else if ((pr = p.right) != null && h >= pr.hash)
743 >                            s = pr;
744 >                        if (s != null && (r = getTreeNode(h, k, s)) != null)
745 >                            return r;
746 >                    }
747                  }
748 <                e = e.next;
748 >                else
749 >                    dir = (h < ph) ? -1 : 1;
750 >                p = (dir > 0) ? p.right : p.left;
751              }
752 <            break;
752 >            return null;
753          }
366        return null;
367    }
754  
755 <    /** Implementation for put and putIfAbsent **/
756 <    private final Object internalPut(Object k, Object v, boolean replace) {
757 <        int h = spread(k.hashCode());
758 <        Object oldVal = null;  // the previous value or null if none
759 <        Node[] tab = table;
760 <        for (;;) {
761 <            Node e; int i;
762 <            if (tab == null)
763 <                tab = grow(0);
764 <            else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
765 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
755 >        /**
756 >         * Wrapper for getTreeNode used by CHM.get. Tries to obtain
757 >         * read-lock to call getTreeNode, but during failure to get
758 >         * lock, searches along next links.
759 >         */
760 >        final Object getValue(int h, Object k) {
761 >            Node r = null;
762 >            int c = getState(); // Must read lock state first
763 >            for (Node e = first; e != null; e = e.next) {
764 >                if (c <= 0 && compareAndSetState(c, c - 1)) {
765 >                    try {
766 >                        r = getTreeNode(h, k, root);
767 >                    } finally {
768 >                        releaseShared(0);
769 >                    }
770                      break;
771 +                }
772 +                else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
773 +                    r = e;
774 +                    break;
775 +                }
776 +                else
777 +                    c = getState();
778 +            }
779 +            return r == null ? null : r.val;
780 +        }
781 +
782 +        /**
783 +         * Finds or adds a node.
784 +         * @return null if added
785 +         */
786 +        @SuppressWarnings("unchecked") final TreeNode putTreeNode
787 +            (int h, Object k, Object v) {
788 +            Class<?> c = k.getClass();
789 +            TreeNode pp = root, p = null;
790 +            int dir = 0;
791 +            while (pp != null) { // find existing node or leaf to insert at
792 +                int ph;  Object pk; Class<?> pc;
793 +                p = pp;
794 +                if ((ph = p.hash) == h) {
795 +                    if ((pk = p.key) == k || k.equals(pk))
796 +                        return p;
797 +                    if (c != (pc = pk.getClass()) ||
798 +                        !(k instanceof Comparable) ||
799 +                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
800 +                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
801 +                        TreeNode r = null, s = null, pl, pr;
802 +                        if (dir >= 0) {
803 +                            if ((pl = p.left) != null && h <= pl.hash)
804 +                                s = pl;
805 +                        }
806 +                        else if ((pr = p.right) != null && h >= pr.hash)
807 +                            s = pr;
808 +                        if (s != null && (r = getTreeNode(h, k, s)) != null)
809 +                            return r;
810 +                    }
811 +                }
812 +                else
813 +                    dir = (h < ph) ? -1 : 1;
814 +                pp = (dir > 0) ? p.right : p.left;
815 +            }
816 +
817 +            TreeNode f = first;
818 +            TreeNode x = first = new TreeNode(h, k, v, f, p);
819 +            if (p == null)
820 +                root = x;
821 +            else { // attach and rebalance; adapted from CLR
822 +                TreeNode xp, xpp;
823 +                if (f != null)
824 +                    f.prev = x;
825 +                if (dir <= 0)
826 +                    p.left = x;
827 +                else
828 +                    p.right = x;
829 +                x.red = true;
830 +                while (x != null && (xp = x.parent) != null && xp.red &&
831 +                       (xpp = xp.parent) != null) {
832 +                    TreeNode xppl = xpp.left;
833 +                    if (xp == xppl) {
834 +                        TreeNode y = xpp.right;
835 +                        if (y != null && y.red) {
836 +                            y.red = false;
837 +                            xp.red = false;
838 +                            xpp.red = true;
839 +                            x = xpp;
840 +                        }
841 +                        else {
842 +                            if (x == xp.right) {
843 +                                rotateLeft(x = xp);
844 +                                xpp = (xp = x.parent) == null ? null : xp.parent;
845 +                            }
846 +                            if (xp != null) {
847 +                                xp.red = false;
848 +                                if (xpp != null) {
849 +                                    xpp.red = true;
850 +                                    rotateRight(xpp);
851 +                                }
852 +                            }
853 +                        }
854 +                    }
855 +                    else {
856 +                        TreeNode y = xppl;
857 +                        if (y != null && y.red) {
858 +                            y.red = false;
859 +                            xp.red = false;
860 +                            xpp.red = true;
861 +                            x = xpp;
862 +                        }
863 +                        else {
864 +                            if (x == xp.left) {
865 +                                rotateRight(x = xp);
866 +                                xpp = (xp = x.parent) == null ? null : xp.parent;
867 +                            }
868 +                            if (xp != null) {
869 +                                xp.red = false;
870 +                                if (xpp != null) {
871 +                                    xpp.red = true;
872 +                                    rotateLeft(xpp);
873 +                                }
874 +                            }
875 +                        }
876 +                    }
877 +                }
878 +                TreeNode r = root;
879 +                if (r != null && r.red)
880 +                    r.red = false;
881 +            }
882 +            return null;
883 +        }
884 +
885 +        /**
886 +         * Removes the given node, that must be present before this
887 +         * call.  This is messier than typical red-black deletion code
888 +         * because we cannot swap the contents of an interior node
889 +         * with a leaf successor that is pinned by "next" pointers
890 +         * that are accessible independently of lock. So instead we
891 +         * swap the tree linkages.
892 +         */
893 +        final void deleteTreeNode(TreeNode p) {
894 +            TreeNode next = (TreeNode)p.next; // unlink traversal pointers
895 +            TreeNode pred = p.prev;
896 +            if (pred == null)
897 +                first = next;
898 +            else
899 +                pred.next = next;
900 +            if (next != null)
901 +                next.prev = pred;
902 +            TreeNode replacement;
903 +            TreeNode pl = p.left;
904 +            TreeNode pr = p.right;
905 +            if (pl != null && pr != null) {
906 +                TreeNode s = pr, sl;
907 +                while ((sl = s.left) != null) // find successor
908 +                    s = sl;
909 +                boolean c = s.red; s.red = p.red; p.red = c; // swap colors
910 +                TreeNode sr = s.right;
911 +                TreeNode pp = p.parent;
912 +                if (s == pr) { // p was s's direct parent
913 +                    p.parent = s;
914 +                    s.right = p;
915 +                }
916 +                else {
917 +                    TreeNode sp = s.parent;
918 +                    if ((p.parent = sp) != null) {
919 +                        if (s == sp.left)
920 +                            sp.left = p;
921 +                        else
922 +                            sp.right = p;
923 +                    }
924 +                    if ((s.right = pr) != null)
925 +                        pr.parent = s;
926 +                }
927 +                p.left = null;
928 +                if ((p.right = sr) != null)
929 +                    sr.parent = p;
930 +                if ((s.left = pl) != null)
931 +                    pl.parent = s;
932 +                if ((s.parent = pp) == null)
933 +                    root = s;
934 +                else if (p == pp.left)
935 +                    pp.left = s;
936 +                else
937 +                    pp.right = s;
938 +                replacement = sr;
939 +            }
940 +            else
941 +                replacement = (pl != null) ? pl : pr;
942 +            TreeNode pp = p.parent;
943 +            if (replacement == null) {
944 +                if (pp == null) {
945 +                    root = null;
946 +                    return;
947 +                }
948 +                replacement = p;
949              }
382            else if (e.hash < 0)
383                tab = (Node[])e.key;
950              else {
951 <                boolean validated = false;
952 <                boolean checkSize = false;
953 <                synchronized (e) {
954 <                    Node first = e;
955 <                    for (;;) {
956 <                        Object ek, ev;
957 <                        if ((ev = e.val) == null)
958 <                            break;
959 <                        if (e.hash == h && (ek = e.key) != null &&
960 <                            (k == ek || k.equals(ek))) {
961 <                            if (tabAt(tab, i) == first) {
962 <                                validated = true;
963 <                                oldVal = ev;
964 <                                if (replace)
965 <                                    e.val = v;
951 >                replacement.parent = pp;
952 >                if (pp == null)
953 >                    root = replacement;
954 >                else if (p == pp.left)
955 >                    pp.left = replacement;
956 >                else
957 >                    pp.right = replacement;
958 >                p.left = p.right = p.parent = null;
959 >            }
960 >            if (!p.red) { // rebalance, from CLR
961 >                TreeNode x = replacement;
962 >                while (x != null) {
963 >                    TreeNode xp, xpl;
964 >                    if (x.red || (xp = x.parent) == null) {
965 >                        x.red = false;
966 >                        break;
967 >                    }
968 >                    if (x == (xpl = xp.left)) {
969 >                        TreeNode sib = xp.right;
970 >                        if (sib != null && sib.red) {
971 >                            sib.red = false;
972 >                            xp.red = true;
973 >                            rotateLeft(xp);
974 >                            sib = (xp = x.parent) == null ? null : xp.right;
975 >                        }
976 >                        if (sib == null)
977 >                            x = xp;
978 >                        else {
979 >                            TreeNode sl = sib.left, sr = sib.right;
980 >                            if ((sr == null || !sr.red) &&
981 >                                (sl == null || !sl.red)) {
982 >                                sib.red = true;
983 >                                x = xp;
984 >                            }
985 >                            else {
986 >                                if (sr == null || !sr.red) {
987 >                                    if (sl != null)
988 >                                        sl.red = false;
989 >                                    sib.red = true;
990 >                                    rotateRight(sib);
991 >                                    sib = (xp = x.parent) == null ? null : xp.right;
992 >                                }
993 >                                if (sib != null) {
994 >                                    sib.red = (xp == null) ? false : xp.red;
995 >                                    if ((sr = sib.right) != null)
996 >                                        sr.red = false;
997 >                                }
998 >                                if (xp != null) {
999 >                                    xp.red = false;
1000 >                                    rotateLeft(xp);
1001 >                                }
1002 >                                x = root;
1003                              }
401                            break;
1004                          }
1005 <                        Node last = e;
1006 <                        if ((e = e.next) == null) {
1007 <                            if (tabAt(tab, i) == first) {
1008 <                                validated = true;
1009 <                                last.next = new Node(h, k, v, null);
1010 <                                if (last != first || tab.length <= 64)
1011 <                                    checkSize = true;
1005 >                    }
1006 >                    else { // symmetric
1007 >                        TreeNode sib = xpl;
1008 >                        if (sib != null && sib.red) {
1009 >                            sib.red = false;
1010 >                            xp.red = true;
1011 >                            rotateRight(xp);
1012 >                            sib = (xp = x.parent) == null ? null : xp.left;
1013 >                        }
1014 >                        if (sib == null)
1015 >                            x = xp;
1016 >                        else {
1017 >                            TreeNode sl = sib.left, sr = sib.right;
1018 >                            if ((sl == null || !sl.red) &&
1019 >                                (sr == null || !sr.red)) {
1020 >                                sib.red = true;
1021 >                                x = xp;
1022 >                            }
1023 >                            else {
1024 >                                if (sl == null || !sl.red) {
1025 >                                    if (sr != null)
1026 >                                        sr.red = false;
1027 >                                    sib.red = true;
1028 >                                    rotateLeft(sib);
1029 >                                    sib = (xp = x.parent) == null ? null : xp.left;
1030 >                                }
1031 >                                if (sib != null) {
1032 >                                    sib.red = (xp == null) ? false : xp.red;
1033 >                                    if ((sl = sib.left) != null)
1034 >                                        sl.red = false;
1035 >                                }
1036 >                                if (xp != null) {
1037 >                                    xp.red = false;
1038 >                                    rotateRight(xp);
1039 >                                }
1040 >                                x = root;
1041                              }
411                            break;
1042                          }
1043                      }
1044                  }
1045 <                if (validated) {
1046 <                    if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1047 <                        resizing == 0 && counter.sum() >= threshold)
1048 <                        grow(0);
1049 <                    break;
1045 >            }
1046 >            if (p == replacement && (pp = p.parent) != null) {
1047 >                if (p == pp.left) // detach pointers
1048 >                    pp.left = null;
1049 >                else if (p == pp.right)
1050 >                    pp.right = null;
1051 >                p.parent = null;
1052 >            }
1053 >        }
1054 >    }
1055 >
1056 >    /* ---------------- Collision reduction methods -------------- */
1057 >
1058 >    /**
1059 >     * Spreads higher bits to lower, and also forces top 2 bits to 0.
1060 >     * Because the table uses power-of-two masking, sets of hashes
1061 >     * that vary only in bits above the current mask will always
1062 >     * collide. (Among known examples are sets of Float keys holding
1063 >     * consecutive whole numbers in small tables.)  To counter this,
1064 >     * we apply a transform that spreads the impact of higher bits
1065 >     * downward. There is a tradeoff between speed, utility, and
1066 >     * quality of bit-spreading. Because many common sets of hashes
1067 >     * are already reasonably distributed across bits (so don't benefit
1068 >     * from spreading), and because we use trees to handle large sets
1069 >     * of collisions in bins, we don't need excessively high quality.
1070 >     */
1071 >    private static final int spread(int h) {
1072 >        h ^= (h >>> 18) ^ (h >>> 12);
1073 >        return (h ^ (h >>> 10)) & HASH_BITS;
1074 >    }
1075 >
1076 >    /**
1077 >     * Replaces a list bin with a tree bin. Call only when locked.
1078 >     * Fails to replace if the given key is non-comparable or table
1079 >     * is, or needs, resizing.
1080 >     */
1081 >    private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
1082 >        if ((key instanceof Comparable) &&
1083 >            (tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
1084 >            TreeBin t = new TreeBin();
1085 >            for (Node e = tabAt(tab, index); e != null; e = e.next)
1086 >                t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
1087 >            setTabAt(tab, index, new Node(MOVED, t, null, null));
1088 >        }
1089 >    }
1090 >
1091 >    /* ---------------- Internal access and update methods -------------- */
1092 >
1093 >    /** Implementation for get and containsKey */
1094 >    private final Object internalGet(Object k) {
1095 >        int h = spread(k.hashCode());
1096 >        retry: for (Node[] tab = table; tab != null;) {
1097 >            Node e, p; Object ek, ev; int eh;      // locals to read fields once
1098 >            for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1099 >                if ((eh = e.hash) == MOVED) {
1100 >                    if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1101 >                        return ((TreeBin)ek).getValue(h, k);
1102 >                    else {                        // restart with new table
1103 >                        tab = (Node[])ek;
1104 >                        continue retry;
1105 >                    }
1106                  }
1107 +                else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1108 +                         ((ek = e.key) == k || k.equals(ek)))
1109 +                    return ev;
1110              }
1111 +            break;
1112          }
1113 <        if (oldVal == null)
424 <            counter.increment();
425 <        return oldVal;
1113 >        return null;
1114      }
1115  
1116      /**
1117 <     * Covers the four public remove/replace methods: Replaces node
1118 <     * value with v, conditional upon match of cv if non-null.  If
1119 <     * resulting value is null, delete.
1117 >     * Implementation for the four public remove/replace methods:
1118 >     * Replaces node value with v, conditional upon match of cv if
1119 >     * non-null.  If resulting value is null, delete.
1120       */
1121      private final Object internalReplace(Object k, Object v, Object cv) {
1122          int h = spread(k.hashCode());
1123          Object oldVal = null;
1124 <        Node e; int i;
1125 <        Node[] tab = table;
1126 <        while (tab != null &&
1127 <               (e = tabAt(tab, i = (tab.length - 1) & h)) != null) {
1128 <            if (e.hash < 0)
1129 <                tab = (Node[])e.key;
1130 <            else {
1124 >        for (Node[] tab = table;;) {
1125 >            Node f; int i, fh; Object fk;
1126 >            if (tab == null ||
1127 >                (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1128 >                break;
1129 >            else if ((fh = f.hash) == MOVED) {
1130 >                if ((fk = f.key) instanceof TreeBin) {
1131 >                    TreeBin t = (TreeBin)fk;
1132 >                    boolean validated = false;
1133 >                    boolean deleted = false;
1134 >                    t.acquire(0);
1135 >                    try {
1136 >                        if (tabAt(tab, i) == f) {
1137 >                            validated = true;
1138 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1139 >                            if (p != null) {
1140 >                                Object pv = p.val;
1141 >                                if (cv == null || cv == pv || cv.equals(pv)) {
1142 >                                    oldVal = pv;
1143 >                                    if ((p.val = v) == null) {
1144 >                                        deleted = true;
1145 >                                        t.deleteTreeNode(p);
1146 >                                    }
1147 >                                }
1148 >                            }
1149 >                        }
1150 >                    } finally {
1151 >                        t.release(0);
1152 >                    }
1153 >                    if (validated) {
1154 >                        if (deleted)
1155 >                            counter.add(-1L);
1156 >                        break;
1157 >                    }
1158 >                }
1159 >                else
1160 >                    tab = (Node[])fk;
1161 >            }
1162 >            else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1163 >                break;                          // rules out possible existence
1164 >            else if ((fh & LOCKED) != 0) {
1165 >                checkForResize();               // try resizing if can't get lock
1166 >                f.tryAwaitLock(tab, i);
1167 >            }
1168 >            else if (f.casHash(fh, fh | LOCKED)) {
1169                  boolean validated = false;
1170                  boolean deleted = false;
1171 <                synchronized (e) {
1172 <                    Node pred = null;
1173 <                    Node first = e;
1174 <                    for (;;) {
1175 <                        Object ek, ev;
1176 <                        if ((ev = e.val) == null)
1177 <                            break;
1178 <                        if (e.hash == h && (ek = e.key) != null &&
453 <                            (k == ek || k.equals(ek))) {
454 <                            if (tabAt(tab, i) == first) {
455 <                                validated = true;
1171 >                try {
1172 >                    if (tabAt(tab, i) == f) {
1173 >                        validated = true;
1174 >                        for (Node e = f, pred = null;;) {
1175 >                            Object ek, ev;
1176 >                            if ((e.hash & HASH_BITS) == h &&
1177 >                                ((ev = e.val) != null) &&
1178 >                                ((ek = e.key) == k || k.equals(ek))) {
1179                                  if (cv == null || cv == ev || cv.equals(ev)) {
1180                                      oldVal = ev;
1181                                      if ((e.val = v) == null) {
# Line 464 | Line 1187 | public class ConcurrentHashMapV8<K, V>
1187                                              setTabAt(tab, i, en);
1188                                      }
1189                                  }
1190 +                                break;
1191                              }
1192 <                            break;
1193 <                        }
1194 <                        pred = e;
471 <                        if ((e = e.next) == null) {
472 <                            if (tabAt(tab, i) == first)
473 <                                validated = true;
474 <                            break;
1192 >                            pred = e;
1193 >                            if ((e = e.next) == null)
1194 >                                break;
1195                          }
1196                      }
1197 +                } finally {
1198 +                    if (!f.casHash(fh | LOCKED, fh)) {
1199 +                        f.hash = fh;
1200 +                        synchronized (f) { f.notifyAll(); };
1201 +                    }
1202                  }
1203                  if (validated) {
1204                      if (deleted)
1205 <                        counter.decrement();
1205 >                        counter.add(-1L);
1206                      break;
1207                  }
1208              }
# Line 485 | Line 1210 | public class ConcurrentHashMapV8<K, V>
1210          return oldVal;
1211      }
1212  
1213 <    /** Implementation for computeIfAbsent and compute */
1214 <    @SuppressWarnings("unchecked")
1215 <    private final V internalCompute(K k,
1216 <                                    MappingFunction<? super K, ? extends V> f,
1217 <                                    boolean replace) {
1213 >    /*
1214 >     * Internal versions of the six insertion methods, each a
1215 >     * little more complicated than the last. All have
1216 >     * the same basic structure as the first (internalPut):
1217 >     *  1. If table uninitialized, create
1218 >     *  2. If bin empty, try to CAS new node
1219 >     *  3. If bin stale, use new table
1220 >     *  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1221 >     *  5. Lock and validate; if valid, scan and add or update
1222 >     *
1223 >     * The others interweave other checks and/or alternative actions:
1224 >     *  * Plain put checks for and performs resize after insertion.
1225 >     *  * putIfAbsent prescans for mapping without lock (and fails to add
1226 >     *    if present), which also makes pre-emptive resize checks worthwhile.
1227 >     *  * computeIfAbsent extends form used in putIfAbsent with additional
1228 >     *    mechanics to deal with, calls, potential exceptions and null
1229 >     *    returns from function call.
1230 >     *  * compute uses the same function-call mechanics, but without
1231 >     *    the prescans
1232 >     *  * merge acts as putIfAbsent in the absent case, but invokes the
1233 >     *    update function if present
1234 >     *  * putAll attempts to pre-allocate enough table space
1235 >     *    and more lazily performs count updates and checks.
1236 >     *
1237 >     * Someday when details settle down a bit more, it might be worth
1238 >     * some factoring to reduce sprawl.
1239 >     */
1240 >
1241 >    /** Implementation for put */
1242 >    private final Object internalPut(Object k, Object v) {
1243          int h = spread(k.hashCode());
1244 <        V val = null;
1245 <        boolean added = false;
1246 <        boolean validated = false;
497 <        Node[] tab = table;
498 <        do {
499 <            Node e; int i;
1244 >        int count = 0;
1245 >        for (Node[] tab = table;;) {
1246 >            int i; Node f; int fh; Object fk;
1247              if (tab == null)
1248 <                tab = grow(0);
1249 <            else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1250 <                Node node = new Node(h, k, null, null);
1251 <                synchronized (node) {
1252 <                    if (casTabAt(tab, i, null, node)) {
1253 <                        validated = true;
1254 <                        try {
1255 <                            val = f.map(k);
1256 <                            if (val != null) {
1257 <                                node.val = val;
1258 <                                added = true;
1248 >                tab = initTable();
1249 >            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1250 >                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1251 >                    break;                   // no lock when adding to empty bin
1252 >            }
1253 >            else if ((fh = f.hash) == MOVED) {
1254 >                if ((fk = f.key) instanceof TreeBin) {
1255 >                    TreeBin t = (TreeBin)fk;
1256 >                    Object oldVal = null;
1257 >                    t.acquire(0);
1258 >                    try {
1259 >                        if (tabAt(tab, i) == f) {
1260 >                            count = 2;
1261 >                            TreeNode p = t.putTreeNode(h, k, v);
1262 >                            if (p != null) {
1263 >                                oldVal = p.val;
1264 >                                p.val = v;
1265                              }
513                        } finally {
514                            if (!added)
515                                setTabAt(tab, i, null);
1266                          }
1267 +                    } finally {
1268 +                        t.release(0);
1269 +                    }
1270 +                    if (count != 0) {
1271 +                        if (oldVal != null)
1272 +                            return oldVal;
1273 +                        break;
1274                      }
1275                  }
1276 +                else
1277 +                    tab = (Node[])fk;
1278              }
1279 <            else if (e.hash < 0)
1280 <                tab = (Node[])e.key;
1281 <            else if (Thread.holdsLock(e))
1282 <                throw new IllegalStateException("Recursive map computation");
1279 >            else if ((fh & LOCKED) != 0) {
1280 >                checkForResize();
1281 >                f.tryAwaitLock(tab, i);
1282 >            }
1283 >            else if (f.casHash(fh, fh | LOCKED)) {
1284 >                Object oldVal = null;
1285 >                try {                        // needed in case equals() throws
1286 >                    if (tabAt(tab, i) == f) {
1287 >                        count = 1;
1288 >                        for (Node e = f;; ++count) {
1289 >                            Object ek, ev;
1290 >                            if ((e.hash & HASH_BITS) == h &&
1291 >                                (ev = e.val) != null &&
1292 >                                ((ek = e.key) == k || k.equals(ek))) {
1293 >                                oldVal = ev;
1294 >                                e.val = v;
1295 >                                break;
1296 >                            }
1297 >                            Node last = e;
1298 >                            if ((e = e.next) == null) {
1299 >                                last.next = new Node(h, k, v, null);
1300 >                                if (count >= TREE_THRESHOLD)
1301 >                                    replaceWithTreeBin(tab, i, k);
1302 >                                break;
1303 >                            }
1304 >                        }
1305 >                    }
1306 >                } finally {                  // unlock and signal if needed
1307 >                    if (!f.casHash(fh | LOCKED, fh)) {
1308 >                        f.hash = fh;
1309 >                        synchronized (f) { f.notifyAll(); };
1310 >                    }
1311 >                }
1312 >                if (count != 0) {
1313 >                    if (oldVal != null)
1314 >                        return oldVal;
1315 >                    if (tab.length <= 64)
1316 >                        count = 2;
1317 >                    break;
1318 >                }
1319 >            }
1320 >        }
1321 >        counter.add(1L);
1322 >        if (count > 1)
1323 >            checkForResize();
1324 >        return null;
1325 >    }
1326 >
1327 >    /** Implementation for putIfAbsent */
1328 >    private final Object internalPutIfAbsent(Object k, Object v) {
1329 >        int h = spread(k.hashCode());
1330 >        int count = 0;
1331 >        for (Node[] tab = table;;) {
1332 >            int i; Node f; int fh; Object fk, fv;
1333 >            if (tab == null)
1334 >                tab = initTable();
1335 >            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1336 >                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1337 >                    break;
1338 >            }
1339 >            else if ((fh = f.hash) == MOVED) {
1340 >                if ((fk = f.key) instanceof TreeBin) {
1341 >                    TreeBin t = (TreeBin)fk;
1342 >                    Object oldVal = null;
1343 >                    t.acquire(0);
1344 >                    try {
1345 >                        if (tabAt(tab, i) == f) {
1346 >                            count = 2;
1347 >                            TreeNode p = t.putTreeNode(h, k, v);
1348 >                            if (p != null)
1349 >                                oldVal = p.val;
1350 >                        }
1351 >                    } finally {
1352 >                        t.release(0);
1353 >                    }
1354 >                    if (count != 0) {
1355 >                        if (oldVal != null)
1356 >                            return oldVal;
1357 >                        break;
1358 >                    }
1359 >                }
1360 >                else
1361 >                    tab = (Node[])fk;
1362 >            }
1363 >            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1364 >                     ((fk = f.key) == k || k.equals(fk)))
1365 >                return fv;
1366              else {
1367 <                boolean checkSize = false;
1368 <                synchronized (e) {
1369 <                    Node first = e;
528 <                    for (;;) {
1367 >                Node g = f.next;
1368 >                if (g != null) { // at least 2 nodes -- search and maybe resize
1369 >                    for (Node e = g;;) {
1370                          Object ek, ev;
1371 <                        if ((ev = e.val) == null)
1371 >                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1372 >                            ((ek = e.key) == k || k.equals(ek)))
1373 >                            return ev;
1374 >                        if ((e = e.next) == null) {
1375 >                            checkForResize();
1376                              break;
1377 <                        if (e.hash == h && (ek = e.key) != null &&
1378 <                            (k == ek || k.equals(ek))) {
1379 <                            if (tabAt(tab, i) == first) {
1380 <                                validated = true;
1381 <                                if (replace && (ev = f.map(k)) != null)
1382 <                                    e.val = ev;
1383 <                                val = (V)ev;
1377 >                        }
1378 >                    }
1379 >                }
1380 >                if (((fh = f.hash) & LOCKED) != 0) {
1381 >                    checkForResize();
1382 >                    f.tryAwaitLock(tab, i);
1383 >                }
1384 >                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1385 >                    Object oldVal = null;
1386 >                    try {
1387 >                        if (tabAt(tab, i) == f) {
1388 >                            count = 1;
1389 >                            for (Node e = f;; ++count) {
1390 >                                Object ek, ev;
1391 >                                if ((e.hash & HASH_BITS) == h &&
1392 >                                    (ev = e.val) != null &&
1393 >                                    ((ek = e.key) == k || k.equals(ek))) {
1394 >                                    oldVal = ev;
1395 >                                    break;
1396 >                                }
1397 >                                Node last = e;
1398 >                                if ((e = e.next) == null) {
1399 >                                    last.next = new Node(h, k, v, null);
1400 >                                    if (count >= TREE_THRESHOLD)
1401 >                                        replaceWithTreeBin(tab, i, k);
1402 >                                    break;
1403 >                                }
1404                              }
540                            break;
1405                          }
1406 <                        Node last = e;
1406 >                    } finally {
1407 >                        if (!f.casHash(fh | LOCKED, fh)) {
1408 >                            f.hash = fh;
1409 >                            synchronized (f) { f.notifyAll(); };
1410 >                        }
1411 >                    }
1412 >                    if (count != 0) {
1413 >                        if (oldVal != null)
1414 >                            return oldVal;
1415 >                        if (tab.length <= 64)
1416 >                            count = 2;
1417 >                        break;
1418 >                    }
1419 >                }
1420 >            }
1421 >        }
1422 >        counter.add(1L);
1423 >        if (count > 1)
1424 >            checkForResize();
1425 >        return null;
1426 >    }
1427 >
1428 >    /** Implementation for computeIfAbsent */
1429 >    private final Object internalComputeIfAbsent(K k,
1430 >                                                 Fun<? super K, ?> mf) {
1431 >        int h = spread(k.hashCode());
1432 >        Object val = null;
1433 >        int count = 0;
1434 >        for (Node[] tab = table;;) {
1435 >            Node f; int i, fh; Object fk, fv;
1436 >            if (tab == null)
1437 >                tab = initTable();
1438 >            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1439 >                Node node = new Node(fh = h | LOCKED, k, null, null);
1440 >                if (casTabAt(tab, i, null, node)) {
1441 >                    count = 1;
1442 >                    try {
1443 >                        if ((val = mf.apply(k)) != null)
1444 >                            node.val = val;
1445 >                    } finally {
1446 >                        if (val == null)
1447 >                            setTabAt(tab, i, null);
1448 >                        if (!node.casHash(fh, h)) {
1449 >                            node.hash = h;
1450 >                            synchronized (node) { node.notifyAll(); };
1451 >                        }
1452 >                    }
1453 >                }
1454 >                if (count != 0)
1455 >                    break;
1456 >            }
1457 >            else if ((fh = f.hash) == MOVED) {
1458 >                if ((fk = f.key) instanceof TreeBin) {
1459 >                    TreeBin t = (TreeBin)fk;
1460 >                    boolean added = false;
1461 >                    t.acquire(0);
1462 >                    try {
1463 >                        if (tabAt(tab, i) == f) {
1464 >                            count = 1;
1465 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1466 >                            if (p != null)
1467 >                                val = p.val;
1468 >                            else if ((val = mf.apply(k)) != null) {
1469 >                                added = true;
1470 >                                count = 2;
1471 >                                t.putTreeNode(h, k, val);
1472 >                            }
1473 >                        }
1474 >                    } finally {
1475 >                        t.release(0);
1476 >                    }
1477 >                    if (count != 0) {
1478 >                        if (!added)
1479 >                            return val;
1480 >                        break;
1481 >                    }
1482 >                }
1483 >                else
1484 >                    tab = (Node[])fk;
1485 >            }
1486 >            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1487 >                     ((fk = f.key) == k || k.equals(fk)))
1488 >                return fv;
1489 >            else {
1490 >                Node g = f.next;
1491 >                if (g != null) {
1492 >                    for (Node e = g;;) {
1493 >                        Object ek, ev;
1494 >                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1495 >                            ((ek = e.key) == k || k.equals(ek)))
1496 >                            return ev;
1497                          if ((e = e.next) == null) {
1498 <                            if (tabAt(tab, i) == first) {
1499 <                                validated = true;
1500 <                                if ((val = f.map(k)) != null) {
1501 <                                    last.next = new Node(h, k, val, null);
1502 <                                    added = true;
1503 <                                    if (last != first || tab.length <= 64)
1504 <                                        checkSize = true;
1498 >                            checkForResize();
1499 >                            break;
1500 >                        }
1501 >                    }
1502 >                }
1503 >                if (((fh = f.hash) & LOCKED) != 0) {
1504 >                    checkForResize();
1505 >                    f.tryAwaitLock(tab, i);
1506 >                }
1507 >                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1508 >                    boolean added = false;
1509 >                    try {
1510 >                        if (tabAt(tab, i) == f) {
1511 >                            count = 1;
1512 >                            for (Node e = f;; ++count) {
1513 >                                Object ek, ev;
1514 >                                if ((e.hash & HASH_BITS) == h &&
1515 >                                    (ev = e.val) != null &&
1516 >                                    ((ek = e.key) == k || k.equals(ek))) {
1517 >                                    val = ev;
1518 >                                    break;
1519 >                                }
1520 >                                Node last = e;
1521 >                                if ((e = e.next) == null) {
1522 >                                    if ((val = mf.apply(k)) != null) {
1523 >                                        added = true;
1524 >                                        last.next = new Node(h, k, val, null);
1525 >                                        if (count >= TREE_THRESHOLD)
1526 >                                            replaceWithTreeBin(tab, i, k);
1527 >                                    }
1528 >                                    break;
1529                                  }
1530                              }
1531 <                            break;
1531 >                        }
1532 >                    } finally {
1533 >                        if (!f.casHash(fh | LOCKED, fh)) {
1534 >                            f.hash = fh;
1535 >                            synchronized (f) { f.notifyAll(); };
1536                          }
1537                      }
1538 +                    if (count != 0) {
1539 +                        if (!added)
1540 +                            return val;
1541 +                        if (tab.length <= 64)
1542 +                            count = 2;
1543 +                        break;
1544 +                    }
1545                  }
557                if (checkSize && tab.length < MAXIMUM_CAPACITY &&
558                    resizing == 0 && counter.sum() >= threshold)
559                    grow(0);
1546              }
1547 <        } while (!validated);
1548 <        if (added)
1549 <            counter.increment();
1547 >        }
1548 >        if (val != null) {
1549 >            counter.add(1L);
1550 >            if (count > 1)
1551 >                checkForResize();
1552 >        }
1553          return val;
1554      }
1555  
1556 <    /*
1557 <     * Reclassifies nodes in each bin to new table.  Because we are
1558 <     * using power-of-two expansion, the elements from each bin must
1559 <     * either stay at same index, or move with a power of two
1560 <     * offset. We eliminate unnecessary node creation by catching
1561 <     * cases where old nodes can be reused because their next fields
1562 <     * won't change.  Statistically, at the default threshold, only
1563 <     * about one-sixth of them need cloning when a table doubles. The
1564 <     * nodes they replace will be garbage collectable as soon as they
1565 <     * are no longer referenced by any reader thread that may be in
1566 <     * the midst of concurrently traversing table.
1567 <     *
1568 <     * Transfers are done from the bottom up to preserve iterator
1569 <     * traversability. On each step, the old bin is locked,
1570 <     * moved/copied, and then replaced with a forwarding node.
1571 <     */
1572 <    private static final void transfer(Node[] tab, Node[] nextTab) {
1573 <        int n = tab.length;
1574 <        int mask = nextTab.length - 1;
1575 <        Node fwd = new Node(MOVED, nextTab, null, null);
1576 <        for (int i = n - 1; i >= 0; --i) {
1577 <            for (Node e;;) {
1578 <                if ((e = tabAt(tab, i)) == null) {
1579 <                    if (casTabAt(tab, i, e, fwd))
1556 >    /** Implementation for compute */
1557 >    @SuppressWarnings("unchecked") private final Object internalCompute
1558 >        (K k, boolean onlyIfPresent, BiFun<? super K, ? super V, ? extends V> mf) {
1559 >        int h = spread(k.hashCode());
1560 >        Object val = null;
1561 >        int delta = 0;
1562 >        int count = 0;
1563 >        for (Node[] tab = table;;) {
1564 >            Node f; int i, fh; Object fk;
1565 >            if (tab == null)
1566 >                tab = initTable();
1567 >            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1568 >                if (onlyIfPresent)
1569 >                    break;
1570 >                Node node = new Node(fh = h | LOCKED, k, null, null);
1571 >                if (casTabAt(tab, i, null, node)) {
1572 >                    try {
1573 >                        count = 1;
1574 >                        if ((val = mf.apply(k, null)) != null) {
1575 >                            node.val = val;
1576 >                            delta = 1;
1577 >                        }
1578 >                    } finally {
1579 >                        if (delta == 0)
1580 >                            setTabAt(tab, i, null);
1581 >                        if (!node.casHash(fh, h)) {
1582 >                            node.hash = h;
1583 >                            synchronized (node) { node.notifyAll(); };
1584 >                        }
1585 >                    }
1586 >                }
1587 >                if (count != 0)
1588 >                    break;
1589 >            }
1590 >            else if ((fh = f.hash) == MOVED) {
1591 >                if ((fk = f.key) instanceof TreeBin) {
1592 >                    TreeBin t = (TreeBin)fk;
1593 >                    t.acquire(0);
1594 >                    try {
1595 >                        if (tabAt(tab, i) == f) {
1596 >                            count = 1;
1597 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1598 >                            Object pv = (p == null) ? null : p.val;
1599 >                            if ((val = mf.apply(k, (V)pv)) != null) {
1600 >                                if (p != null)
1601 >                                    p.val = val;
1602 >                                else {
1603 >                                    count = 2;
1604 >                                    delta = 1;
1605 >                                    t.putTreeNode(h, k, val);
1606 >                                }
1607 >                            }
1608 >                            else if (p != null) {
1609 >                                delta = -1;
1610 >                                t.deleteTreeNode(p);
1611 >                            }
1612 >                        }
1613 >                    } finally {
1614 >                        t.release(0);
1615 >                    }
1616 >                    if (count != 0)
1617                          break;
1618                  }
1619 <                else {
1620 <                    boolean validated = false;
1621 <                    synchronized (e) {
1622 <                        int idx = e.hash & mask;
1623 <                        Node lastRun = e;
1624 <                        for (Node p = e.next; p != null; p = p.next) {
1625 <                            int j = p.hash & mask;
1626 <                            if (j != idx) {
1627 <                                idx = j;
1628 <                                lastRun = p;
1619 >                else
1620 >                    tab = (Node[])fk;
1621 >            }
1622 >            else if ((fh & LOCKED) != 0) {
1623 >                checkForResize();
1624 >                f.tryAwaitLock(tab, i);
1625 >            }
1626 >            else if (f.casHash(fh, fh | LOCKED)) {
1627 >                try {
1628 >                    if (tabAt(tab, i) == f) {
1629 >                        count = 1;
1630 >                        for (Node e = f, pred = null;; ++count) {
1631 >                            Object ek, ev;
1632 >                            if ((e.hash & HASH_BITS) == h &&
1633 >                                (ev = e.val) != null &&
1634 >                                ((ek = e.key) == k || k.equals(ek))) {
1635 >                                val = mf.apply(k, (V)ev);
1636 >                                if (val != null)
1637 >                                    e.val = val;
1638 >                                else {
1639 >                                    delta = -1;
1640 >                                    Node en = e.next;
1641 >                                    if (pred != null)
1642 >                                        pred.next = en;
1643 >                                    else
1644 >                                        setTabAt(tab, i, en);
1645 >                                }
1646 >                                break;
1647 >                            }
1648 >                            pred = e;
1649 >                            if ((e = e.next) == null) {
1650 >                                if (!onlyIfPresent && (val = mf.apply(k, null)) != null) {
1651 >                                    pred.next = new Node(h, k, val, null);
1652 >                                    delta = 1;
1653 >                                    if (count >= TREE_THRESHOLD)
1654 >                                        replaceWithTreeBin(tab, i, k);
1655 >                                }
1656 >                                break;
1657                              }
1658                          }
1659 <                        if (tabAt(tab, i) == e) {
1660 <                            validated = true;
1661 <                            relaxedSetTabAt(nextTab, idx, lastRun);
1662 <                            for (Node p = e; p != lastRun; p = p.next) {
1663 <                                int h = p.hash;
1664 <                                int j = h & mask;
1665 <                                Node r = relaxedTabAt(nextTab, j);
1666 <                                relaxedSetTabAt(nextTab, j,
1667 <                                                new Node(h, p.key, p.val, r));
1659 >                    }
1660 >                } finally {
1661 >                    if (!f.casHash(fh | LOCKED, fh)) {
1662 >                        f.hash = fh;
1663 >                        synchronized (f) { f.notifyAll(); };
1664 >                    }
1665 >                }
1666 >                if (count != 0) {
1667 >                    if (tab.length <= 64)
1668 >                        count = 2;
1669 >                    break;
1670 >                }
1671 >            }
1672 >        }
1673 >        if (delta != 0) {
1674 >            counter.add((long)delta);
1675 >            if (count > 1)
1676 >                checkForResize();
1677 >        }
1678 >        return val;
1679 >    }
1680 >
1681 >    /** Implementation for merge */
1682 >    @SuppressWarnings("unchecked") private final Object internalMerge
1683 >        (K k, V v, BiFun<? super V, ? super V, ? extends V> mf) {
1684 >        int h = spread(k.hashCode());
1685 >        Object val = null;
1686 >        int delta = 0;
1687 >        int count = 0;
1688 >        for (Node[] tab = table;;) {
1689 >            int i; Node f; int fh; Object fk, fv;
1690 >            if (tab == null)
1691 >                tab = initTable();
1692 >            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1693 >                if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1694 >                    delta = 1;
1695 >                    val = v;
1696 >                    break;
1697 >                }
1698 >            }
1699 >            else if ((fh = f.hash) == MOVED) {
1700 >                if ((fk = f.key) instanceof TreeBin) {
1701 >                    TreeBin t = (TreeBin)fk;
1702 >                    t.acquire(0);
1703 >                    try {
1704 >                        if (tabAt(tab, i) == f) {
1705 >                            count = 1;
1706 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1707 >                            val = (p == null) ? v : mf.apply((V)p.val, v);
1708 >                            if (val != null) {
1709 >                                if (p != null)
1710 >                                    p.val = val;
1711 >                                else {
1712 >                                    count = 2;
1713 >                                    delta = 1;
1714 >                                    t.putTreeNode(h, k, val);
1715 >                                }
1716 >                            }
1717 >                            else if (p != null) {
1718 >                                delta = -1;
1719 >                                t.deleteTreeNode(p);
1720                              }
615                            setTabAt(tab, i, fwd);
1721                          }
1722 +                    } finally {
1723 +                        t.release(0);
1724                      }
1725 <                    if (validated)
1725 >                    if (count != 0)
1726                          break;
1727                  }
1728 +                else
1729 +                    tab = (Node[])fk;
1730              }
1731 +            else if ((fh & LOCKED) != 0) {
1732 +                checkForResize();
1733 +                f.tryAwaitLock(tab, i);
1734 +            }
1735 +            else if (f.casHash(fh, fh | LOCKED)) {
1736 +                try {
1737 +                    if (tabAt(tab, i) == f) {
1738 +                        count = 1;
1739 +                        for (Node e = f, pred = null;; ++count) {
1740 +                            Object ek, ev;
1741 +                            if ((e.hash & HASH_BITS) == h &&
1742 +                                (ev = e.val) != null &&
1743 +                                ((ek = e.key) == k || k.equals(ek))) {
1744 +                                val = mf.apply(v, (V)ev);
1745 +                                if (val != null)
1746 +                                    e.val = val;
1747 +                                else {
1748 +                                    delta = -1;
1749 +                                    Node en = e.next;
1750 +                                    if (pred != null)
1751 +                                        pred.next = en;
1752 +                                    else
1753 +                                        setTabAt(tab, i, en);
1754 +                                }
1755 +                                break;
1756 +                            }
1757 +                            pred = e;
1758 +                            if ((e = e.next) == null) {
1759 +                                val = v;
1760 +                                pred.next = new Node(h, k, val, null);
1761 +                                delta = 1;
1762 +                                if (count >= TREE_THRESHOLD)
1763 +                                    replaceWithTreeBin(tab, i, k);
1764 +                                break;
1765 +                            }
1766 +                        }
1767 +                    }
1768 +                } finally {
1769 +                    if (!f.casHash(fh | LOCKED, fh)) {
1770 +                        f.hash = fh;
1771 +                        synchronized (f) { f.notifyAll(); };
1772 +                    }
1773 +                }
1774 +                if (count != 0) {
1775 +                    if (tab.length <= 64)
1776 +                        count = 2;
1777 +                    break;
1778 +                }
1779 +            }
1780 +        }
1781 +        if (delta != 0) {
1782 +            counter.add((long)delta);
1783 +            if (count > 1)
1784 +                checkForResize();
1785          }
1786 +        return val;
1787      }
1788  
1789 +    /** Implementation for putAll */
1790 +    private final void internalPutAll(Map<?, ?> m) {
1791 +        tryPresize(m.size());
1792 +        long delta = 0L;     // number of uncommitted additions
1793 +        boolean npe = false; // to throw exception on exit for nulls
1794 +        try {                // to clean up counts on other exceptions
1795 +            for (Map.Entry<?, ?> entry : m.entrySet()) {
1796 +                Object k, v;
1797 +                if (entry == null || (k = entry.getKey()) == null ||
1798 +                    (v = entry.getValue()) == null) {
1799 +                    npe = true;
1800 +                    break;
1801 +                }
1802 +                int h = spread(k.hashCode());
1803 +                for (Node[] tab = table;;) {
1804 +                    int i; Node f; int fh; Object fk;
1805 +                    if (tab == null)
1806 +                        tab = initTable();
1807 +                    else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1808 +                        if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1809 +                            ++delta;
1810 +                            break;
1811 +                        }
1812 +                    }
1813 +                    else if ((fh = f.hash) == MOVED) {
1814 +                        if ((fk = f.key) instanceof TreeBin) {
1815 +                            TreeBin t = (TreeBin)fk;
1816 +                            boolean validated = false;
1817 +                            t.acquire(0);
1818 +                            try {
1819 +                                if (tabAt(tab, i) == f) {
1820 +                                    validated = true;
1821 +                                    TreeNode p = t.getTreeNode(h, k, t.root);
1822 +                                    if (p != null)
1823 +                                        p.val = v;
1824 +                                    else {
1825 +                                        t.putTreeNode(h, k, v);
1826 +                                        ++delta;
1827 +                                    }
1828 +                                }
1829 +                            } finally {
1830 +                                t.release(0);
1831 +                            }
1832 +                            if (validated)
1833 +                                break;
1834 +                        }
1835 +                        else
1836 +                            tab = (Node[])fk;
1837 +                    }
1838 +                    else if ((fh & LOCKED) != 0) {
1839 +                        counter.add(delta);
1840 +                        delta = 0L;
1841 +                        checkForResize();
1842 +                        f.tryAwaitLock(tab, i);
1843 +                    }
1844 +                    else if (f.casHash(fh, fh | LOCKED)) {
1845 +                        int count = 0;
1846 +                        try {
1847 +                            if (tabAt(tab, i) == f) {
1848 +                                count = 1;
1849 +                                for (Node e = f;; ++count) {
1850 +                                    Object ek, ev;
1851 +                                    if ((e.hash & HASH_BITS) == h &&
1852 +                                        (ev = e.val) != null &&
1853 +                                        ((ek = e.key) == k || k.equals(ek))) {
1854 +                                        e.val = v;
1855 +                                        break;
1856 +                                    }
1857 +                                    Node last = e;
1858 +                                    if ((e = e.next) == null) {
1859 +                                        ++delta;
1860 +                                        last.next = new Node(h, k, v, null);
1861 +                                        if (count >= TREE_THRESHOLD)
1862 +                                            replaceWithTreeBin(tab, i, k);
1863 +                                        break;
1864 +                                    }
1865 +                                }
1866 +                            }
1867 +                        } finally {
1868 +                            if (!f.casHash(fh | LOCKED, fh)) {
1869 +                                f.hash = fh;
1870 +                                synchronized (f) { f.notifyAll(); };
1871 +                            }
1872 +                        }
1873 +                        if (count != 0) {
1874 +                            if (count > 1) {
1875 +                                counter.add(delta);
1876 +                                delta = 0L;
1877 +                                checkForResize();
1878 +                            }
1879 +                            break;
1880 +                        }
1881 +                    }
1882 +                }
1883 +            }
1884 +        } finally {
1885 +            if (delta != 0)
1886 +                counter.add(delta);
1887 +        }
1888 +        if (npe)
1889 +            throw new NullPointerException();
1890 +    }
1891 +
1892 +    /* ---------------- Table Initialization and Resizing -------------- */
1893 +
1894      /**
1895 <     * If not already resizing, initializes or creates next table and
1896 <     * transfers bins. Rechecks occupancy after a transfer to see if
628 <     * another resize is already needed because resizings are lagging
629 <     * additions.
630 <     *
631 <     * @param sizeHint overridden capacity target (nonzero only from putAll)
632 <     * @return current table
1895 >     * Returns a power of two table size for the given desired capacity.
1896 >     * See Hackers Delight, sec 3.2
1897       */
1898 <    private final Node[] grow(int sizeHint) {
1899 <        if (resizing == 0 &&
1900 <            UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
1901 <            try {
1902 <                for (;;) {
1903 <                    int cap, n;
1904 <                    Node[] tab = table;
1905 <                    if (tab == null) {
1906 <                        int c = initCap;
1907 <                        if (c < sizeHint)
1908 <                            c = sizeHint;
1909 <                        if (c == DEFAULT_CAPACITY)
1910 <                            cap = c;
1911 <                        else if (c >= MAXIMUM_CAPACITY)
1912 <                            cap = MAXIMUM_CAPACITY;
1913 <                        else {
1914 <                            cap = MINIMUM_CAPACITY;
1915 <                            while (cap < c)
1916 <                                cap <<= 1;
1917 <                        }
1898 >    private static final int tableSizeFor(int c) {
1899 >        int n = c - 1;
1900 >        n |= n >>> 1;
1901 >        n |= n >>> 2;
1902 >        n |= n >>> 4;
1903 >        n |= n >>> 8;
1904 >        n |= n >>> 16;
1905 >        return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1906 >    }
1907 >
1908 >    /**
1909 >     * Initializes table, using the size recorded in sizeCtl.
1910 >     */
1911 >    private final Node[] initTable() {
1912 >        Node[] tab; int sc;
1913 >        while ((tab = table) == null) {
1914 >            if ((sc = sizeCtl) < 0)
1915 >                Thread.yield(); // lost initialization race; just spin
1916 >            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1917 >                try {
1918 >                    if ((tab = table) == null) {
1919 >                        int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1920 >                        tab = table = new Node[n];
1921 >                        sc = n - (n >>> 2);
1922                      }
1923 <                    else if ((n = tab.length) < MAXIMUM_CAPACITY &&
1924 <                             (sizeHint <= 0 || n < sizeHint))
657 <                        cap = n << 1;
658 <                    else
659 <                        break;
660 <                    threshold = (int)(cap * loadFactor) - THRESHOLD_OFFSET;
661 <                    Node[] nextTab = new Node[cap];
662 <                    if (tab != null)
663 <                        transfer(tab, nextTab);
664 <                    table = nextTab;
665 <                    if (tab == null || cap >= MAXIMUM_CAPACITY ||
666 <                        (sizeHint > 0 && cap >= sizeHint) ||
667 <                        counter.sum() < threshold)
668 <                        break;
1923 >                } finally {
1924 >                    sizeCtl = sc;
1925                  }
1926 <            } finally {
671 <                resizing = 0;
1926 >                break;
1927              }
1928          }
1929 <        else if (table == null)
675 <            Thread.yield(); // lost initialization race; just spin
676 <        return table;
1929 >        return tab;
1930      }
1931  
1932      /**
1933 <     * Implementation for putAll and constructor with Map
1934 <     * argument. Tries to first override initial capacity or grow
1935 <     * based on map size to pre-allocate table space.
1933 >     * If table is too small and not already resizing, creates next
1934 >     * table and transfers bins.  Rechecks occupancy after a transfer
1935 >     * to see if another resize is already needed because resizings
1936 >     * are lagging additions.
1937       */
1938 <    private final void internalPutAll(Map<? extends K, ? extends V> m) {
1939 <        int s = m.size();
1940 <        grow((s >= (MAXIMUM_CAPACITY >>> 1)) ? s : s + (s >>> 1));
1941 <        for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
1942 <            Object k = e.getKey();
1943 <            Object v = e.getValue();
1944 <            if (k == null || v == null)
1945 <                throw new NullPointerException();
1946 <            internalPut(k, v, true);
1938 >    private final void checkForResize() {
1939 >        Node[] tab; int n, sc;
1940 >        while ((tab = table) != null &&
1941 >               (n = tab.length) < MAXIMUM_CAPACITY &&
1942 >               (sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1943 >               UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1944 >            try {
1945 >                if (tab == table) {
1946 >                    table = rebuild(tab);
1947 >                    sc = (n << 1) - (n >>> 1);
1948 >                }
1949 >            } finally {
1950 >                sizeCtl = sc;
1951 >            }
1952          }
1953      }
1954  
1955      /**
1956 <     * Implementation for clear. Steps through each bin, removing all nodes.
1956 >     * Tries to presize table to accommodate the given number of elements.
1957 >     *
1958 >     * @param size number of elements (doesn't need to be perfectly accurate)
1959       */
1960 <    private final void internalClear() {
1961 <        long deletions = 0L;
1962 <        int i = 0;
1963 <        Node[] tab = table;
1964 <        while (tab != null && i < tab.length) {
1965 <            Node e = tabAt(tab, i);
1966 <            if (e == null)
1967 <                ++i;
1968 <            else if (e.hash < 0)
1969 <                tab = (Node[])e.key;
1970 <            else {
1960 >    private final void tryPresize(int size) {
1961 >        int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1962 >            tableSizeFor(size + (size >>> 1) + 1);
1963 >        int sc;
1964 >        while ((sc = sizeCtl) >= 0) {
1965 >            Node[] tab = table; int n;
1966 >            if (tab == null || (n = tab.length) == 0) {
1967 >                n = (sc > c) ? sc : c;
1968 >                if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1969 >                    try {
1970 >                        if (table == tab) {
1971 >                            table = new Node[n];
1972 >                            sc = n - (n >>> 2);
1973 >                        }
1974 >                    } finally {
1975 >                        sizeCtl = sc;
1976 >                    }
1977 >                }
1978 >            }
1979 >            else if (c <= sc || n >= MAXIMUM_CAPACITY)
1980 >                break;
1981 >            else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1982 >                try {
1983 >                    if (table == tab) {
1984 >                        table = rebuild(tab);
1985 >                        sc = (n << 1) - (n >>> 1);
1986 >                    }
1987 >                } finally {
1988 >                    sizeCtl = sc;
1989 >                }
1990 >            }
1991 >        }
1992 >    }
1993 >
1994 >    /*
1995 >     * Moves and/or copies the nodes in each bin to new table. See
1996 >     * above for explanation.
1997 >     *
1998 >     * @return the new table
1999 >     */
2000 >    private static final Node[] rebuild(Node[] tab) {
2001 >        int n = tab.length;
2002 >        Node[] nextTab = new Node[n << 1];
2003 >        Node fwd = new Node(MOVED, nextTab, null, null);
2004 >        int[] buffer = null;       // holds bins to revisit; null until needed
2005 >        Node rev = null;           // reverse forwarder; null until needed
2006 >        int nbuffered = 0;         // the number of bins in buffer list
2007 >        int bufferIndex = 0;       // buffer index of current buffered bin
2008 >        int bin = n - 1;           // current non-buffered bin or -1 if none
2009 >
2010 >        for (int i = bin;;) {      // start upwards sweep
2011 >            int fh; Node f;
2012 >            if ((f = tabAt(tab, i)) == null) {
2013 >                if (bin >= 0) {    // Unbuffered; no lock needed (or available)
2014 >                    if (!casTabAt(tab, i, f, fwd))
2015 >                        continue;
2016 >                }
2017 >                else {             // transiently use a locked forwarding node
2018 >                    Node g = new Node(MOVED|LOCKED, nextTab, null, null);
2019 >                    if (!casTabAt(tab, i, f, g))
2020 >                        continue;
2021 >                    setTabAt(nextTab, i, null);
2022 >                    setTabAt(nextTab, i + n, null);
2023 >                    setTabAt(tab, i, fwd);
2024 >                    if (!g.casHash(MOVED|LOCKED, MOVED)) {
2025 >                        g.hash = MOVED;
2026 >                        synchronized (g) { g.notifyAll(); }
2027 >                    }
2028 >                }
2029 >            }
2030 >            else if ((fh = f.hash) == MOVED) {
2031 >                Object fk = f.key;
2032 >                if (fk instanceof TreeBin) {
2033 >                    TreeBin t = (TreeBin)fk;
2034 >                    boolean validated = false;
2035 >                    t.acquire(0);
2036 >                    try {
2037 >                        if (tabAt(tab, i) == f) {
2038 >                            validated = true;
2039 >                            splitTreeBin(nextTab, i, t);
2040 >                            setTabAt(tab, i, fwd);
2041 >                        }
2042 >                    } finally {
2043 >                        t.release(0);
2044 >                    }
2045 >                    if (!validated)
2046 >                        continue;
2047 >                }
2048 >            }
2049 >            else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
2050                  boolean validated = false;
2051 <                synchronized (e) {
2052 <                    if (tabAt(tab, i) == e) {
2051 >                try {              // split to lo and hi lists; copying as needed
2052 >                    if (tabAt(tab, i) == f) {
2053                          validated = true;
2054 <                        do {
2055 <                            if (e.val != null) {
716 <                                e.val = null;
717 <                                ++deletions;
718 <                            }
719 <                        } while ((e = e.next) != null);
720 <                        setTabAt(tab, i, null);
2054 >                        splitBin(nextTab, i, f);
2055 >                        setTabAt(tab, i, fwd);
2056                      }
2057 <                }
2058 <                if (validated) {
2059 <                    ++i;
2060 <                    if (deletions > THRESHOLD_OFFSET) { // bound lag in counts
726 <                        counter.add(-deletions);
727 <                        deletions = 0L;
2057 >                } finally {
2058 >                    if (!f.casHash(fh | LOCKED, fh)) {
2059 >                        f.hash = fh;
2060 >                        synchronized (f) { f.notifyAll(); };
2061                      }
2062                  }
2063 +                if (!validated)
2064 +                    continue;
2065              }
2066 +            else {
2067 +                if (buffer == null) // initialize buffer for revisits
2068 +                    buffer = new int[TRANSFER_BUFFER_SIZE];
2069 +                if (bin < 0 && bufferIndex > 0) {
2070 +                    int j = buffer[--bufferIndex];
2071 +                    buffer[bufferIndex] = i;
2072 +                    i = j;         // swap with another bin
2073 +                    continue;
2074 +                }
2075 +                if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
2076 +                    f.tryAwaitLock(tab, i);
2077 +                    continue;      // no other options -- block
2078 +                }
2079 +                if (rev == null)   // initialize reverse-forwarder
2080 +                    rev = new Node(MOVED, tab, null, null);
2081 +                if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
2082 +                    continue;      // recheck before adding to list
2083 +                buffer[nbuffered++] = i;
2084 +                setTabAt(nextTab, i, rev);     // install place-holders
2085 +                setTabAt(nextTab, i + n, rev);
2086 +            }
2087 +
2088 +            if (bin > 0)
2089 +                i = --bin;
2090 +            else if (buffer != null && nbuffered > 0) {
2091 +                bin = -1;
2092 +                i = buffer[bufferIndex = --nbuffered];
2093 +            }
2094 +            else
2095 +                return nextTab;
2096          }
732        if (deletions != 0L)
733            counter.add(-deletions);
2097      }
2098  
2099      /**
2100 <     * Base class for key, value, and entry iterators, plus internal
2101 <     * implementations of public traversal-based methods, to avoid
739 <     * duplicating traversal code.
2100 >     * Splits a normal bin with list headed by e into lo and hi parts;
2101 >     * installs in given table.
2102       */
2103 <    class HashIterator {
2104 <        private Node next;          // the next entry to return
2105 <        private Node[] tab;         // current table; updated if resized
2106 <        private Node lastReturned;  // the last entry returned, for remove
2107 <        private Object nextVal;     // cached value of next
2108 <        private int index;          // index of bin to use next
2109 <        private int baseIndex;      // current index of initial table
2110 <        private final int baseSize; // initial table size
2103 >    private static void splitBin(Node[] nextTab, int i, Node e) {
2104 >        int bit = nextTab.length >>> 1; // bit to split on
2105 >        int runBit = e.hash & bit;
2106 >        Node lastRun = e, lo = null, hi = null;
2107 >        for (Node p = e.next; p != null; p = p.next) {
2108 >            int b = p.hash & bit;
2109 >            if (b != runBit) {
2110 >                runBit = b;
2111 >                lastRun = p;
2112 >            }
2113 >        }
2114 >        if (runBit == 0)
2115 >            lo = lastRun;
2116 >        else
2117 >            hi = lastRun;
2118 >        for (Node p = e; p != lastRun; p = p.next) {
2119 >            int ph = p.hash & HASH_BITS;
2120 >            Object pk = p.key, pv = p.val;
2121 >            if ((ph & bit) == 0)
2122 >                lo = new Node(ph, pk, pv, lo);
2123 >            else
2124 >                hi = new Node(ph, pk, pv, hi);
2125 >        }
2126 >        setTabAt(nextTab, i, lo);
2127 >        setTabAt(nextTab, i + bit, hi);
2128 >    }
2129  
2130 <        HashIterator() {
2131 <            Node[] t = tab = table;
2132 <            if (t == null)
2133 <                baseSize = 0;
2130 >    /**
2131 >     * Splits a tree bin into lo and hi parts; installs in given table.
2132 >     */
2133 >    private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
2134 >        int bit = nextTab.length >>> 1;
2135 >        TreeBin lt = new TreeBin();
2136 >        TreeBin ht = new TreeBin();
2137 >        int lc = 0, hc = 0;
2138 >        for (Node e = t.first; e != null; e = e.next) {
2139 >            int h = e.hash & HASH_BITS;
2140 >            Object k = e.key, v = e.val;
2141 >            if ((h & bit) == 0) {
2142 >                ++lc;
2143 >                lt.putTreeNode(h, k, v);
2144 >            }
2145              else {
2146 <                baseSize = t.length;
2147 <                advance(null);
2146 >                ++hc;
2147 >                ht.putTreeNode(h, k, v);
2148              }
2149          }
2150 +        Node ln, hn; // throw away trees if too small
2151 +        if (lc <= (TREE_THRESHOLD >>> 1)) {
2152 +            ln = null;
2153 +            for (Node p = lt.first; p != null; p = p.next)
2154 +                ln = new Node(p.hash, p.key, p.val, ln);
2155 +        }
2156 +        else
2157 +            ln = new Node(MOVED, lt, null, null);
2158 +        setTabAt(nextTab, i, ln);
2159 +        if (hc <= (TREE_THRESHOLD >>> 1)) {
2160 +            hn = null;
2161 +            for (Node p = ht.first; p != null; p = p.next)
2162 +                hn = new Node(p.hash, p.key, p.val, hn);
2163 +        }
2164 +        else
2165 +            hn = new Node(MOVED, ht, null, null);
2166 +        setTabAt(nextTab, i + bit, hn);
2167 +    }
2168  
2169 <        public final boolean hasNext()         { return next != null; }
2170 <        public final boolean hasMoreElements() { return next != null; }
2171 <
2172 <        /**
2173 <         * Advances next.  Normally, iteration proceeds bin-by-bin
2174 <         * traversing lists.  However, if the table has been resized,
2175 <         * then all future steps must traverse both the bin at the
2176 <         * current index as well as at (index + baseSize); and so on
2177 <         * for further resizings. To paranoically cope with potential
2178 <         * (improper) sharing of iterators across threads, table reads
2179 <         * are bounds-checked.
2180 <         */
2181 <        final void advance(Node e) {
2182 <            for (;;) {
2183 <                Node[] t; int i; // for bounds checks
2184 <                if (e != null) {
2185 <                    Object ek = e.key, ev = e.val;
2186 <                    if (ev != null && ek != null) {
2187 <                        nextVal = ev;
2188 <                        next = e;
2189 <                        break;
2169 >    /**
2170 >     * Implementation for clear. Steps through each bin, removing all
2171 >     * nodes.
2172 >     */
2173 >    private final void internalClear() {
2174 >        long delta = 0L; // negative number of deletions
2175 >        int i = 0;
2176 >        Node[] tab = table;
2177 >        while (tab != null && i < tab.length) {
2178 >            int fh; Object fk;
2179 >            Node f = tabAt(tab, i);
2180 >            if (f == null)
2181 >                ++i;
2182 >            else if ((fh = f.hash) == MOVED) {
2183 >                if ((fk = f.key) instanceof TreeBin) {
2184 >                    TreeBin t = (TreeBin)fk;
2185 >                    t.acquire(0);
2186 >                    try {
2187 >                        if (tabAt(tab, i) == f) {
2188 >                            for (Node p = t.first; p != null; p = p.next) {
2189 >                                if (p.val != null) { // (currently always true)
2190 >                                    p.val = null;
2191 >                                    --delta;
2192 >                                }
2193 >                            }
2194 >                            t.first = null;
2195 >                            t.root = null;
2196 >                            ++i;
2197 >                        }
2198 >                    } finally {
2199 >                        t.release(0);
2200                      }
782                    e = e.next;
2201                  }
2202 <                else if (baseIndex < baseSize && (t = tab) != null &&
2203 <                         t.length > (i = index) && i >= 0) {
2204 <                    if ((e = tabAt(t, i)) != null && e.hash < 0) {
2205 <                        tab = (Node[])e.key;
2206 <                        e = null;
2202 >                else
2203 >                    tab = (Node[])fk;
2204 >            }
2205 >            else if ((fh & LOCKED) != 0) {
2206 >                counter.add(delta); // opportunistically update count
2207 >                delta = 0L;
2208 >                f.tryAwaitLock(tab, i);
2209 >            }
2210 >            else if (f.casHash(fh, fh | LOCKED)) {
2211 >                try {
2212 >                    if (tabAt(tab, i) == f) {
2213 >                        for (Node e = f; e != null; e = e.next) {
2214 >                            if (e.val != null) {  // (currently always true)
2215 >                                e.val = null;
2216 >                                --delta;
2217 >                            }
2218 >                        }
2219 >                        setTabAt(tab, i, null);
2220 >                        ++i;
2221 >                    }
2222 >                } finally {
2223 >                    if (!f.casHash(fh | LOCKED, fh)) {
2224 >                        f.hash = fh;
2225 >                        synchronized (f) { f.notifyAll(); };
2226                      }
790                    else if (i + baseSize < t.length)
791                        index += baseSize;    // visit forwarded upper slots
792                    else
793                        index = ++baseIndex;
794                }
795                else {
796                    next = null;
797                    break;
2227                  }
2228              }
2229          }
2230 +        if (delta != 0)
2231 +            counter.add(delta);
2232 +    }
2233  
2234 <        final Object nextKey() {
803 <            Node e = next;
804 <            if (e == null)
805 <                throw new NoSuchElementException();
806 <            Object k = e.key;
807 <            advance((lastReturned = e).next);
808 <            return k;
809 <        }
2234 >    /* ----------------Table Traversal -------------- */
2235  
2236 <        final Object nextValue() {
2237 <            Node e = next;
2238 <            if (e == null)
2239 <                throw new NoSuchElementException();
2240 <            Object v = nextVal;
2241 <            advance((lastReturned = e).next);
2242 <            return v;
2236 >    /**
2237 >     * Encapsulates traversal for methods such as containsValue; also
2238 >     * serves as a base class for other iterators and bulk tasks.
2239 >     *
2240 >     * At each step, the iterator snapshots the key ("nextKey") and
2241 >     * value ("nextVal") of a valid node (i.e., one that, at point of
2242 >     * snapshot, has a non-null user value). Because val fields can
2243 >     * change (including to null, indicating deletion), field nextVal
2244 >     * might not be accurate at point of use, but still maintains the
2245 >     * weak consistency property of holding a value that was once
2246 >     * valid.
2247 >     *
2248 >     * Internal traversals directly access these fields, as in:
2249 >     * {@code while (it.advance() != null) { process(it.nextKey); }}
2250 >     *
2251 >     * Exported iterators must track whether the iterator has advanced
2252 >     * (in hasNext vs next) (by setting/checking/nulling field
2253 >     * nextVal), and then extract key, value, or key-value pairs as
2254 >     * return values of next().
2255 >     *
2256 >     * The iterator visits once each still-valid node that was
2257 >     * reachable upon iterator construction. It might miss some that
2258 >     * were added to a bin after the bin was visited, which is OK wrt
2259 >     * consistency guarantees. Maintaining this property in the face
2260 >     * of possible ongoing resizes requires a fair amount of
2261 >     * bookkeeping state that is difficult to optimize away amidst
2262 >     * volatile accesses.  Even so, traversal maintains reasonable
2263 >     * throughput.
2264 >     *
2265 >     * Normally, iteration proceeds bin-by-bin traversing lists.
2266 >     * However, if the table has been resized, then all future steps
2267 >     * must traverse both the bin at the current index as well as at
2268 >     * (index + baseSize); and so on for further resizings. To
2269 >     * paranoically cope with potential sharing by users of iterators
2270 >     * across threads, iteration terminates if a bounds checks fails
2271 >     * for a table read.
2272 >     *
2273 >     * This class extends ForkJoinTask to streamline parallel
2274 >     * iteration in bulk operations (see BulkTask). This adds only an
2275 >     * int of space overhead, which is close enough to negligible in
2276 >     * cases where it is not needed to not worry about it.  Because
2277 >     * ForkJoinTask is Serializable, but iterators need not be, we
2278 >     * need to add warning suppressions.
2279 >     */
2280 >    @SuppressWarnings("serial") static class Traverser<K,V,R> extends ForkJoinTask<R> {
2281 >        final ConcurrentHashMapV8<K, V> map;
2282 >        Node next;           // the next entry to use
2283 >        Node last;           // the last entry used
2284 >        Object nextKey;      // cached key field of next
2285 >        Object nextVal;      // cached val field of next
2286 >        Node[] tab;          // current table; updated if resized
2287 >        int index;           // index of bin to use next
2288 >        int baseIndex;       // current index of initial table
2289 >        int baseLimit;       // index bound for initial table
2290 >        final int baseSize;  // initial table size
2291 >
2292 >        /** Creates iterator for all entries in the table. */
2293 >        Traverser(ConcurrentHashMapV8<K, V> map) {
2294 >            this.tab = (this.map = map).table;
2295 >            baseLimit = baseSize = (tab == null) ? 0 : tab.length;
2296 >        }
2297 >
2298 >        /** Creates iterator for split() methods */
2299 >        Traverser(Traverser<K,V,?> it) {
2300 >            this.map = it.map;
2301 >            this.tab = it.tab;
2302 >            this.baseSize = it.baseSize;
2303 >            it.baseLimit = this.index = this.baseIndex =
2304 >                ((this.baseLimit = it.baseLimit) + it.baseIndex + 1) >>> 1;
2305          }
2306  
2307 <        final WriteThroughEntry nextEntry() {
2308 <            Node e = next;
2309 <            if (e == null)
2310 <                throw new NoSuchElementException();
2311 <            WriteThroughEntry entry =
2312 <                new WriteThroughEntry(e.key, nextVal);
2313 <            advance((lastReturned = e).next);
2314 <            return entry;
2307 >        /**
2308 >         * Advances next; returns nextVal or null if terminated.
2309 >         * See above for explanation.
2310 >         */
2311 >        final Object advance() {
2312 >            Node e = last = next;
2313 >            Object ev = null;
2314 >            outer: do {
2315 >                if (e != null)                  // advance past used/skipped node
2316 >                    e = e.next;
2317 >                while (e == null) {             // get to next non-null bin
2318 >                    Node[] t; int b, i, n; Object ek; // checks must use locals
2319 >                    if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2320 >                        (t = tab) == null || i >= (n = t.length))
2321 >                        break outer;
2322 >                    else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2323 >                        if ((ek = e.key) instanceof TreeBin)
2324 >                            e = ((TreeBin)ek).first;
2325 >                        else {
2326 >                            tab = (Node[])ek;
2327 >                            continue;           // restarts due to null val
2328 >                        }
2329 >                    }                           // visit upper slots if present
2330 >                    index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2331 >                }
2332 >                nextKey = e.key;
2333 >            } while ((ev = e.val) == null);    // skip deleted or special nodes
2334 >            next = e;
2335 >            return nextVal = ev;
2336          }
2337  
2338          public final void remove() {
2339 <            if (lastReturned == null)
2339 >            if (nextVal == null && last == null)
2340 >                advance();
2341 >            Node e = last;
2342 >            if (e == null)
2343                  throw new IllegalStateException();
2344 <            ConcurrentHashMapV8.this.remove(lastReturned.key);
2345 <            lastReturned = null;
835 <        }
836 <
837 <        /** Helper for serialization */
838 <        final void writeEntries(java.io.ObjectOutputStream s)
839 <            throws java.io.IOException {
840 <            Node e;
841 <            while ((e = next) != null) {
842 <                s.writeObject(e.key);
843 <                s.writeObject(nextVal);
844 <                advance(e.next);
845 <            }
846 <        }
847 <
848 <        /** Helper for containsValue */
849 <        final boolean containsVal(Object value) {
850 <            if (value != null) {
851 <                Node e;
852 <                while ((e = next) != null) {
853 <                    Object v = nextVal;
854 <                    if (value == v || value.equals(v))
855 <                        return true;
856 <                    advance(e.next);
857 <                }
858 <            }
859 <            return false;
2344 >            last = null;
2345 >            map.remove(e.key);
2346          }
2347  
2348 <        /** Helper for Map.hashCode */
2349 <        final int mapHashCode() {
864 <            int h = 0;
865 <            Node e;
866 <            while ((e = next) != null) {
867 <                h += e.key.hashCode() ^ nextVal.hashCode();
868 <                advance(e.next);
869 <            }
870 <            return h;
2348 >        public final boolean hasNext() {
2349 >            return nextVal != null || advance() != null;
2350          }
2351  
2352 <        /** Helper for Map.toString */
2353 <        final String mapToString() {
2354 <            Node e = next;
2355 <            if (e == null)
877 <                return "{}";
878 <            StringBuilder sb = new StringBuilder();
879 <            sb.append('{');
880 <            for (;;) {
881 <                sb.append(e.key   == this ? "(this Map)" : e.key);
882 <                sb.append('=');
883 <                sb.append(nextVal == this ? "(this Map)" : nextVal);
884 <                advance(e.next);
885 <                if ((e = next) != null)
886 <                    sb.append(',').append(' ');
887 <                else
888 <                    return sb.append('}').toString();
889 <            }
890 <        }
2352 >        public final boolean hasMoreElements() { return hasNext(); }
2353 >        public final void setRawResult(Object x) { }
2354 >        public R getRawResult() { return null; }
2355 >        public boolean exec() { return true; }
2356      }
2357  
2358      /* ---------------- Public operations -------------- */
2359  
2360      /**
2361 <     * Creates a new, empty map with the specified initial
897 <     * capacity, load factor and concurrency level.
898 <     *
899 <     * @param initialCapacity the initial capacity. The implementation
900 <     * performs internal sizing to accommodate this many elements.
901 <     * @param loadFactor  the load factor threshold, used to control resizing.
902 <     * Resizing may be performed when the average number of elements per
903 <     * bin exceeds this threshold.
904 <     * @param concurrencyLevel the estimated number of concurrently
905 <     * updating threads. The implementation may use this value as
906 <     * a sizing hint.
907 <     * @throws IllegalArgumentException if the initial capacity is
908 <     * negative or the load factor or concurrencyLevel are
909 <     * nonpositive.
2361 >     * Creates a new, empty map with the default initial table size (16).
2362       */
2363 <    public ConcurrentHashMapV8(int initialCapacity,
912 <                             float loadFactor, int concurrencyLevel) {
913 <        if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
914 <            throw new IllegalArgumentException();
915 <        this.initCap = initialCapacity;
916 <        this.loadFactor = loadFactor;
2363 >    public ConcurrentHashMapV8() {
2364          this.counter = new LongAdder();
2365      }
2366  
2367      /**
2368 <     * Creates a new, empty map with the specified initial capacity
2369 <     * and load factor and with the default concurrencyLevel (16).
2368 >     * Creates a new, empty map with an initial table size
2369 >     * accommodating the specified number of elements without the need
2370 >     * to dynamically resize.
2371       *
2372       * @param initialCapacity The implementation performs internal
2373       * sizing to accommodate this many elements.
926     * @param loadFactor  the load factor threshold, used to control resizing.
927     * Resizing may be performed when the average number of elements per
928     * bin exceeds this threshold.
2374       * @throws IllegalArgumentException if the initial capacity of
2375 <     * elements is negative or the load factor is nonpositive
931 <     *
932 <     * @since 1.6
2375 >     * elements is negative
2376       */
2377 <    public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2378 <        this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2377 >    public ConcurrentHashMapV8(int initialCapacity) {
2378 >        if (initialCapacity < 0)
2379 >            throw new IllegalArgumentException();
2380 >        int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2381 >                   MAXIMUM_CAPACITY :
2382 >                   tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2383 >        this.counter = new LongAdder();
2384 >        this.sizeCtl = cap;
2385      }
2386  
2387      /**
2388 <     * Creates a new, empty map with the specified initial capacity,
940 <     * and with default load factor (0.75) and concurrencyLevel (16).
2388 >     * Creates a new map with the same mappings as the given map.
2389       *
2390 <     * @param initialCapacity the initial capacity. The implementation
943 <     * performs internal sizing to accommodate this many elements.
944 <     * @throws IllegalArgumentException if the initial capacity of
945 <     * elements is negative.
2390 >     * @param m the map
2391       */
2392 <    public ConcurrentHashMapV8(int initialCapacity) {
2393 <        this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2392 >    public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2393 >        this.counter = new LongAdder();
2394 >        this.sizeCtl = DEFAULT_CAPACITY;
2395 >        internalPutAll(m);
2396      }
2397  
2398      /**
2399 <     * Creates a new, empty map with a default initial capacity (16),
2400 <     * load factor (0.75) and concurrencyLevel (16).
2399 >     * Creates a new, empty map with an initial table size based on
2400 >     * the given number of elements ({@code initialCapacity}) and
2401 >     * initial table density ({@code loadFactor}).
2402 >     *
2403 >     * @param initialCapacity the initial capacity. The implementation
2404 >     * performs internal sizing to accommodate this many elements,
2405 >     * given the specified load factor.
2406 >     * @param loadFactor the load factor (table density) for
2407 >     * establishing the initial table size
2408 >     * @throws IllegalArgumentException if the initial capacity of
2409 >     * elements is negative or the load factor is nonpositive
2410 >     *
2411 >     * @since 1.6
2412       */
2413 <    public ConcurrentHashMapV8() {
2414 <        this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2413 >    public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2414 >        this(initialCapacity, loadFactor, 1);
2415      }
2416  
2417      /**
2418 <     * Creates a new map with the same mappings as the given map.
2419 <     * The map is created with a capacity of 1.5 times the number
2420 <     * of mappings in the given map or 16 (whichever is greater),
2421 <     * and a default load factor (0.75) and concurrencyLevel (16).
2418 >     * Creates a new, empty map with an initial table size based on
2419 >     * the given number of elements ({@code initialCapacity}), table
2420 >     * density ({@code loadFactor}), and number of concurrently
2421 >     * updating threads ({@code concurrencyLevel}).
2422       *
2423 <     * @param m the map
2423 >     * @param initialCapacity the initial capacity. The implementation
2424 >     * performs internal sizing to accommodate this many elements,
2425 >     * given the specified load factor.
2426 >     * @param loadFactor the load factor (table density) for
2427 >     * establishing the initial table size
2428 >     * @param concurrencyLevel the estimated number of concurrently
2429 >     * updating threads. The implementation may use this value as
2430 >     * a sizing hint.
2431 >     * @throws IllegalArgumentException if the initial capacity is
2432 >     * negative or the load factor or concurrencyLevel are
2433 >     * nonpositive
2434       */
2435 <    public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2436 <        this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2437 <        if (m == null)
2438 <            throw new NullPointerException();
2439 <        internalPutAll(m);
2435 >    public ConcurrentHashMapV8(int initialCapacity,
2436 >                               float loadFactor, int concurrencyLevel) {
2437 >        if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2438 >            throw new IllegalArgumentException();
2439 >        if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2440 >            initialCapacity = concurrencyLevel;   // as estimated threads
2441 >        long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2442 >        int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2443 >            MAXIMUM_CAPACITY : tableSizeFor((int)size);
2444 >        this.counter = new LongAdder();
2445 >        this.sizeCtl = cap;
2446      }
2447  
2448      /**
2449 <     * Returns {@code true} if this map contains no key-value mappings.
976 <     *
977 <     * @return {@code true} if this map contains no key-value mappings
2449 >     * {@inheritDoc}
2450       */
2451      public boolean isEmpty() {
2452          return counter.sum() <= 0L; // ignore transient negative values
2453      }
2454  
2455      /**
2456 <     * Returns the number of key-value mappings in this map.  If the
985 <     * map contains more than {@code Integer.MAX_VALUE} elements, returns
986 <     * {@code Integer.MAX_VALUE}.
987 <     *
988 <     * @return the number of key-value mappings in this map
2456 >     * {@inheritDoc}
2457       */
2458      public int size() {
2459          long n = counter.sum();
2460 <        return ((n >>> 31) == 0) ? (int)n : (n < 0L) ? 0 : Integer.MAX_VALUE;
2460 >        return ((n < 0L) ? 0 :
2461 >                (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2462 >                (int)n);
2463 >    }
2464 >
2465 >    /**
2466 >     * Returns the number of mappings. This method should be used
2467 >     * instead of {@link #size} because a ConcurrentHashMap may
2468 >     * contain more mappings than can be represented as an int. The
2469 >     * value returned is a snapshot; the actual count may differ if
2470 >     * there are ongoing concurrent insertions or removals.
2471 >     *
2472 >     * @return the number of mappings
2473 >     */
2474 >    public long mappingCount() {
2475 >        long n = counter.sum();
2476 >        return (n < 0L) ? 0L : n; // ignore transient negative values
2477      }
2478  
2479      /**
# Line 1003 | Line 2487 | public class ConcurrentHashMapV8<K, V>
2487       *
2488       * @throws NullPointerException if the specified key is null
2489       */
2490 <    @SuppressWarnings("unchecked")
1007 <    public V get(Object key) {
2490 >    @SuppressWarnings("unchecked") public V get(Object key) {
2491          if (key == null)
2492              throw new NullPointerException();
2493          return (V)internalGet(key);
# Line 1016 | Line 2499 | public class ConcurrentHashMapV8<K, V>
2499       * @param  key   possible key
2500       * @return {@code true} if and only if the specified object
2501       *         is a key in this table, as determined by the
2502 <     *         {@code equals} method; {@code false} otherwise.
2502 >     *         {@code equals} method; {@code false} otherwise
2503       * @throws NullPointerException if the specified key is null
2504       */
2505      public boolean containsKey(Object key) {
# Line 1027 | Line 2510 | public class ConcurrentHashMapV8<K, V>
2510  
2511      /**
2512       * Returns {@code true} if this map maps one or more keys to the
2513 <     * specified value. Note: This method requires a full internal
2514 <     * traversal of the hash table, and so is much slower than
1032 <     * method {@code containsKey}.
2513 >     * specified value. Note: This method may require a full traversal
2514 >     * of the map, and is much slower than method {@code containsKey}.
2515       *
2516       * @param value value whose presence in this map is to be tested
2517       * @return {@code true} if this map maps one or more keys to the
# Line 1039 | Line 2521 | public class ConcurrentHashMapV8<K, V>
2521      public boolean containsValue(Object value) {
2522          if (value == null)
2523              throw new NullPointerException();
2524 <        return new HashIterator().containsVal(value);
2524 >        Object v;
2525 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2526 >        while ((v = it.advance()) != null) {
2527 >            if (v == value || value.equals(v))
2528 >                return true;
2529 >        }
2530 >        return false;
2531      }
2532  
2533      /**
# Line 1074 | Line 2562 | public class ConcurrentHashMapV8<K, V>
2562       *         {@code null} if there was no mapping for {@code key}
2563       * @throws NullPointerException if the specified key or value is null
2564       */
2565 <    @SuppressWarnings("unchecked")
1078 <    public V put(K key, V value) {
2565 >    @SuppressWarnings("unchecked") public V put(K key, V value) {
2566          if (key == null || value == null)
2567              throw new NullPointerException();
2568 <        return (V)internalPut(key, value, true);
2568 >        return (V)internalPut(key, value);
2569      }
2570  
2571      /**
# Line 1088 | Line 2575 | public class ConcurrentHashMapV8<K, V>
2575       *         or {@code null} if there was no mapping for the key
2576       * @throws NullPointerException if the specified key or value is null
2577       */
2578 <    @SuppressWarnings("unchecked")
1092 <    public V putIfAbsent(K key, V value) {
2578 >    @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
2579          if (key == null || value == null)
2580              throw new NullPointerException();
2581 <        return (V)internalPut(key, value, false);
2581 >        return (V)internalPutIfAbsent(key, value);
2582      }
2583  
2584      /**
# Line 1103 | Line 2589 | public class ConcurrentHashMapV8<K, V>
2589       * @param m mappings to be stored in this map
2590       */
2591      public void putAll(Map<? extends K, ? extends V> m) {
1106        if (m == null)
1107            throw new NullPointerException();
2592          internalPutAll(m);
2593      }
2594  
2595      /**
2596       * If the specified key is not already associated with a value,
2597 <     * computes its value using the given mappingFunction, and if
2598 <     * non-null, enters it into the map.  This is equivalent to
2599 <     *
2600 <     * <pre>
2601 <     *   if (map.containsKey(key))
2602 <     *       return map.get(key);
2603 <     *   value = mappingFunction.map(key);
2604 <     *   if (value != null)
2605 <     *      map.put(key, value);
2606 <     *   return value;
2607 <     * </pre>
2608 <     *
2609 <     * except that the action is performed atomically.  Some attempted
2610 <     * update operations on this map by other threads may be blocked
2611 <     * while computation is in progress, so the computation should be
2612 <     * short and simple, and must not attempt to update any other
2613 <     * mappings of this Map. The most appropriate usage is to
2597 >     * computes its value using the given mappingFunction and enters
2598 >     * it into the map unless null.  This is equivalent to
2599 >     * <pre> {@code
2600 >     * if (map.containsKey(key))
2601 >     *   return map.get(key);
2602 >     * value = mappingFunction.apply(key);
2603 >     * if (value != null)
2604 >     *   map.put(key, value);
2605 >     * return value;}</pre>
2606 >     *
2607 >     * except that the action is performed atomically.  If the
2608 >     * function returns {@code null} no mapping is recorded. If the
2609 >     * function itself throws an (unchecked) exception, the exception
2610 >     * is rethrown to its caller, and no mapping is recorded.  Some
2611 >     * attempted update operations on this map by other threads may be
2612 >     * blocked while computation is in progress, so the computation
2613 >     * should be short and simple, and must not attempt to update any
2614 >     * other mappings of this Map. The most appropriate usage is to
2615       * construct a new object serving as an initial mapped value, or
2616       * memoized result, as in:
2617 <     * <pre>{@code
2618 <     * map.computeIfAbsent(key, new MappingFunction<K, V>() {
2619 <     *   public V map(K k) { return new Value(f(k)); }};
2620 <     * }</pre>
2617 >     *
2618 >     *  <pre> {@code
2619 >     * map.computeIfAbsent(key, new Fun<K, V>() {
2620 >     *   public V map(K k) { return new Value(f(k)); }});}</pre>
2621       *
2622       * @param key key with which the specified value is to be associated
2623       * @param mappingFunction the function to compute a value
2624       * @return the current (existing or computed) value associated with
2625 <     *         the specified key, or {@code null} if the computation
1141 <     *         returned {@code null}.
2625 >     *         the specified key, or null if the computed value is null.
2626       * @throws NullPointerException if the specified key or mappingFunction
2627 <     *         is null,
2627 >     *         is null
2628       * @throws IllegalStateException if the computation detectably
2629       *         attempts a recursive update to this map that would
2630 <     *         otherwise never complete.
2630 >     *         otherwise never complete
2631       * @throws RuntimeException or Error if the mappingFunction does so,
2632 <     *         in which case the mapping is left unestablished.
2632 >     *         in which case the mapping is left unestablished
2633       */
2634 <    public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2634 >    @SuppressWarnings("unchecked") public V computeIfAbsent
2635 >        (K key, Fun<? super K, ? extends V> mappingFunction) {
2636          if (key == null || mappingFunction == null)
2637              throw new NullPointerException();
2638 <        return internalCompute(key, mappingFunction, false);
2638 >        return (V)internalComputeIfAbsent(key, mappingFunction);
2639      }
2640  
2641      /**
2642 <     * Computes the value associated with the given key using the given
2643 <     * mappingFunction, and if non-null, enters it into the map.  This
2644 <     * is equivalent to
2642 >     * If the given key is present, computes a new mapping value given a key and
2643 >     * its current mapped value. This is equivalent to
2644 >     *  <pre> {@code
2645 >     *   if (map.containsKey(key)) {
2646 >     *     value = remappingFunction.apply(key, map.get(key));
2647 >     *     if (value != null)
2648 >     *       map.put(key, value);
2649 >     *     else
2650 >     *       map.remove(key);
2651 >     *   }
2652 >     * }</pre>
2653       *
2654 <     * <pre>
2655 <     *   value = mappingFunction.map(key);
2654 >     * except that the action is performed atomically.  If the
2655 >     * function returns {@code null}, the mapping is removed.  If the
2656 >     * function itself throws an (unchecked) exception, the exception
2657 >     * is rethrown to its caller, and the current mapping is left
2658 >     * unchanged.  Some attempted update operations on this map by
2659 >     * other threads may be blocked while computation is in progress,
2660 >     * so the computation should be short and simple, and must not
2661 >     * attempt to update any other mappings of this Map. For example,
2662 >     * to either create or append new messages to a value mapping:
2663 >     *
2664 >     * @param key key with which the specified value is to be associated
2665 >     * @param remappingFunction the function to compute a value
2666 >     * @return the new value associated with the specified key, or null if none
2667 >     * @throws NullPointerException if the specified key or remappingFunction
2668 >     *         is null
2669 >     * @throws IllegalStateException if the computation detectably
2670 >     *         attempts a recursive update to this map that would
2671 >     *         otherwise never complete
2672 >     * @throws RuntimeException or Error if the remappingFunction does so,
2673 >     *         in which case the mapping is unchanged
2674 >     */
2675 >    @SuppressWarnings("unchecked") public V computeIfPresent
2676 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2677 >        if (key == null || remappingFunction == null)
2678 >            throw new NullPointerException();
2679 >        return (V)internalCompute(key, true, remappingFunction);
2680 >    }
2681 >
2682 >    /**
2683 >     * Computes a new mapping value given a key and
2684 >     * its current mapped value (or {@code null} if there is no current
2685 >     * mapping). This is equivalent to
2686 >     *  <pre> {@code
2687 >     *   value = remappingFunction.apply(key, map.get(key));
2688       *   if (value != null)
2689 <     *      map.put(key, value);
2689 >     *     map.put(key, value);
2690       *   else
2691 <     *      value = map.get(key);
2692 <     *   return value;
2693 <     * </pre>
2694 <     *
2695 <     * except that the action is performed atomically.  Some attempted
2696 <     * update operations on this map by other threads may be blocked
2697 <     * while computation is in progress, so the computation should be
2698 <     * short and simple, and must not attempt to update any other
2699 <     * mappings of this Map.
2691 >     *     map.remove(key);
2692 >     * }</pre>
2693 >     *
2694 >     * except that the action is performed atomically.  If the
2695 >     * function returns {@code null}, the mapping is removed.  If the
2696 >     * function itself throws an (unchecked) exception, the exception
2697 >     * is rethrown to its caller, and the current mapping is left
2698 >     * unchanged.  Some attempted update operations on this map by
2699 >     * other threads may be blocked while computation is in progress,
2700 >     * so the computation should be short and simple, and must not
2701 >     * attempt to update any other mappings of this Map. For example,
2702 >     * to either create or append new messages to a value mapping:
2703 >     *
2704 >     * <pre> {@code
2705 >     * Map<Key, String> map = ...;
2706 >     * final String msg = ...;
2707 >     * map.compute(key, new BiFun<Key, String, String>() {
2708 >     *   public String apply(Key k, String v) {
2709 >     *    return (v == null) ? msg : v + msg;});}}</pre>
2710       *
2711       * @param key key with which the specified value is to be associated
2712 <     * @param mappingFunction the function to compute a value
2713 <     * @return the current value associated with
2714 <     *         the specified key, or {@code null} if the computation
2715 <     *         returned {@code null} and the value was not otherwise present.
1181 <     * @throws NullPointerException if the specified key or mappingFunction
1182 <     *         is null,
2712 >     * @param remappingFunction the function to compute a value
2713 >     * @return the new value associated with the specified key, or null if none
2714 >     * @throws NullPointerException if the specified key or remappingFunction
2715 >     *         is null
2716       * @throws IllegalStateException if the computation detectably
2717       *         attempts a recursive update to this map that would
2718 <     *         otherwise never complete.
2719 <     * @throws RuntimeException or Error if the mappingFunction does so,
2720 <     *         in which case the mapping is unchanged.
2721 <     */
2722 <    public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2723 <        if (key == null || mappingFunction == null)
2718 >     *         otherwise never complete
2719 >     * @throws RuntimeException or Error if the remappingFunction does so,
2720 >     *         in which case the mapping is unchanged
2721 >     */
2722 >    @SuppressWarnings("unchecked") public V compute
2723 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2724 >        if (key == null || remappingFunction == null)
2725 >            throw new NullPointerException();
2726 >        return (V)internalCompute(key, false, remappingFunction);
2727 >    }
2728 >
2729 >    /**
2730 >     * If the specified key is not already associated
2731 >     * with a value, associate it with the given value.
2732 >     * Otherwise, replace the value with the results of
2733 >     * the given remapping function. This is equivalent to:
2734 >     *  <pre> {@code
2735 >     *   if (!map.containsKey(key))
2736 >     *     map.put(value);
2737 >     *   else {
2738 >     *     newValue = remappingFunction.apply(map.get(key), value);
2739 >     *     if (value != null)
2740 >     *       map.put(key, value);
2741 >     *     else
2742 >     *       map.remove(key);
2743 >     *   }
2744 >     * }</pre>
2745 >     * except that the action is performed atomically.  If the
2746 >     * function returns {@code null}, the mapping is removed.  If the
2747 >     * function itself throws an (unchecked) exception, the exception
2748 >     * is rethrown to its caller, and the current mapping is left
2749 >     * unchanged.  Some attempted update operations on this map by
2750 >     * other threads may be blocked while computation is in progress,
2751 >     * so the computation should be short and simple, and must not
2752 >     * attempt to update any other mappings of this Map.
2753 >     */
2754 >    @SuppressWarnings("unchecked") public V merge
2755 >        (K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
2756 >        if (key == null || value == null || remappingFunction == null)
2757              throw new NullPointerException();
2758 <        return internalCompute(key, mappingFunction, true);
2758 >        return (V)internalMerge(key, value, remappingFunction);
2759      }
2760  
2761      /**
# Line 1201 | Line 2767 | public class ConcurrentHashMapV8<K, V>
2767       *         {@code null} if there was no mapping for {@code key}
2768       * @throws NullPointerException if the specified key is null
2769       */
2770 <    @SuppressWarnings("unchecked")
1205 <    public V remove(Object key) {
2770 >    @SuppressWarnings("unchecked") public V remove(Object key) {
2771          if (key == null)
2772              throw new NullPointerException();
2773          return (V)internalReplace(key, null, null);
# Line 1239 | Line 2804 | public class ConcurrentHashMapV8<K, V>
2804       *         or {@code null} if there was no mapping for the key
2805       * @throws NullPointerException if the specified key or value is null
2806       */
2807 <    @SuppressWarnings("unchecked")
1243 <    public V replace(K key, V value) {
2807 >    @SuppressWarnings("unchecked") public V replace(K key, V value) {
2808          if (key == null || value == null)
2809              throw new NullPointerException();
2810          return (V)internalReplace(key, value, null);
# Line 1270 | Line 2834 | public class ConcurrentHashMapV8<K, V>
2834       * reflect any modifications subsequent to construction.
2835       */
2836      public Set<K> keySet() {
2837 <        Set<K> ks = keySet;
2838 <        return (ks != null) ? ks : (keySet = new KeySet());
2837 >        KeySet<K,V> ks = keySet;
2838 >        return (ks != null) ? ks : (keySet = new KeySet<K,V>(this));
2839      }
2840  
2841      /**
# Line 1291 | Line 2855 | public class ConcurrentHashMapV8<K, V>
2855       * reflect any modifications subsequent to construction.
2856       */
2857      public Collection<V> values() {
2858 <        Collection<V> vs = values;
2859 <        return (vs != null) ? vs : (values = new Values());
2858 >        Values<K,V> vs = values;
2859 >        return (vs != null) ? vs : (values = new Values<K,V>(this));
2860      }
2861  
2862      /**
# Line 1312 | Line 2876 | public class ConcurrentHashMapV8<K, V>
2876       * reflect any modifications subsequent to construction.
2877       */
2878      public Set<Map.Entry<K,V>> entrySet() {
2879 <        Set<Map.Entry<K,V>> es = entrySet;
2880 <        return (es != null) ? es : (entrySet = new EntrySet());
2879 >        EntrySet<K,V> es = entrySet;
2880 >        return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
2881      }
2882  
2883      /**
# Line 1323 | Line 2887 | public class ConcurrentHashMapV8<K, V>
2887       * @see #keySet()
2888       */
2889      public Enumeration<K> keys() {
2890 <        return new KeyIterator();
2890 >        return new KeyIterator<K,V>(this);
2891      }
2892  
2893      /**
# Line 1333 | Line 2897 | public class ConcurrentHashMapV8<K, V>
2897       * @see #values()
2898       */
2899      public Enumeration<V> elements() {
2900 <        return new ValueIterator();
2900 >        return new ValueIterator<K,V>(this);
2901 >    }
2902 >
2903 >    /**
2904 >     * Returns a partitionable iterator of the keys in this map.
2905 >     *
2906 >     * @return a partitionable iterator of the keys in this map
2907 >     */
2908 >    public Spliterator<K> keySpliterator() {
2909 >        return new KeyIterator<K,V>(this);
2910 >    }
2911 >
2912 >    /**
2913 >     * Returns a partitionable iterator of the values in this map.
2914 >     *
2915 >     * @return a partitionable iterator of the values in this map
2916 >     */
2917 >    public Spliterator<V> valueSpliterator() {
2918 >        return new ValueIterator<K,V>(this);
2919 >    }
2920 >
2921 >    /**
2922 >     * Returns a partitionable iterator of the entries in this map.
2923 >     *
2924 >     * @return a partitionable iterator of the entries in this map
2925 >     */
2926 >    public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2927 >        return new EntryIterator<K,V>(this);
2928      }
2929  
2930      /**
# Line 1344 | Line 2935 | public class ConcurrentHashMapV8<K, V>
2935       * @return the hash code value for this map
2936       */
2937      public int hashCode() {
2938 <        return new HashIterator().mapHashCode();
2938 >        int h = 0;
2939 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2940 >        Object v;
2941 >        while ((v = it.advance()) != null) {
2942 >            h += it.nextKey.hashCode() ^ v.hashCode();
2943 >        }
2944 >        return h;
2945      }
2946  
2947      /**
# Line 1359 | Line 2956 | public class ConcurrentHashMapV8<K, V>
2956       * @return a string representation of this map
2957       */
2958      public String toString() {
2959 <        return new HashIterator().mapToString();
2959 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2960 >        StringBuilder sb = new StringBuilder();
2961 >        sb.append('{');
2962 >        Object v;
2963 >        if ((v = it.advance()) != null) {
2964 >            for (;;) {
2965 >                Object k = it.nextKey;
2966 >                sb.append(k == this ? "(this Map)" : k);
2967 >                sb.append('=');
2968 >                sb.append(v == this ? "(this Map)" : v);
2969 >                if ((v = it.advance()) == null)
2970 >                    break;
2971 >                sb.append(',').append(' ');
2972 >            }
2973 >        }
2974 >        return sb.append('}').toString();
2975      }
2976  
2977      /**
# Line 1373 | Line 2985 | public class ConcurrentHashMapV8<K, V>
2985       * @return {@code true} if the specified object is equal to this map
2986       */
2987      public boolean equals(Object o) {
2988 <        if (o == this)
2989 <            return true;
2990 <        if (!(o instanceof Map))
2991 <            return false;
2992 <        Map<?,?> m = (Map<?,?>) o;
2993 <        try {
2994 <            for (Map.Entry<K,V> e : this.entrySet())
2995 <                if (! e.getValue().equals(m.get(e.getKey())))
2988 >        if (o != this) {
2989 >            if (!(o instanceof Map))
2990 >                return false;
2991 >            Map<?,?> m = (Map<?,?>) o;
2992 >            Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2993 >            Object val;
2994 >            while ((val = it.advance()) != null) {
2995 >                Object v = m.get(it.nextKey);
2996 >                if (v == null || (v != val && !v.equals(val)))
2997                      return false;
2998 +            }
2999              for (Map.Entry<?,?> e : m.entrySet()) {
3000 <                Object k = e.getKey();
3001 <                Object v = e.getValue();
3002 <                if (k == null || v == null || !v.equals(get(k)))
3000 >                Object mk, mv, v;
3001 >                if ((mk = e.getKey()) == null ||
3002 >                    (mv = e.getValue()) == null ||
3003 >                    (v = internalGet(mk)) == null ||
3004 >                    (mv != v && !mv.equals(v)))
3005                      return false;
3006              }
3007 <            return true;
3008 <        } catch (ClassCastException unused) {
3009 <            return false;
3010 <        } catch (NullPointerException unused) {
3011 <            return false;
3007 >        }
3008 >        return true;
3009 >    }
3010 >
3011 >    /* ----------------Iterators -------------- */
3012 >
3013 >    @SuppressWarnings("serial") static final class KeyIterator<K,V> extends Traverser<K,V,Object>
3014 >        implements Spliterator<K>, Enumeration<K> {
3015 >        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3016 >        KeyIterator(Traverser<K,V,Object> it) {
3017 >            super(it);
3018 >        }
3019 >        public KeyIterator<K,V> split() {
3020 >            if (last != null || (next != null && nextVal == null))
3021 >                throw new IllegalStateException();
3022 >            return new KeyIterator<K,V>(this);
3023 >        }
3024 >        @SuppressWarnings("unchecked") public final K next() {
3025 >            if (nextVal == null && advance() == null)
3026 >                throw new NoSuchElementException();
3027 >            Object k = nextKey;
3028 >            nextVal = null;
3029 >            return (K) k;
3030 >        }
3031 >
3032 >        public final K nextElement() { return next(); }
3033 >    }
3034 >
3035 >    @SuppressWarnings("serial") static final class ValueIterator<K,V> extends Traverser<K,V,Object>
3036 >        implements Spliterator<V>, Enumeration<V> {
3037 >        ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3038 >        ValueIterator(Traverser<K,V,Object> it) {
3039 >            super(it);
3040 >        }
3041 >        public ValueIterator<K,V> split() {
3042 >            if (last != null || (next != null && nextVal == null))
3043 >                throw new IllegalStateException();
3044 >            return new ValueIterator<K,V>(this);
3045 >        }
3046 >
3047 >        @SuppressWarnings("unchecked") public final V next() {
3048 >            Object v;
3049 >            if ((v = nextVal) == null && (v = advance()) == null)
3050 >                throw new NoSuchElementException();
3051 >            nextVal = null;
3052 >            return (V) v;
3053 >        }
3054 >
3055 >        public final V nextElement() { return next(); }
3056 >    }
3057 >
3058 >    @SuppressWarnings("serial") static final class EntryIterator<K,V> extends Traverser<K,V,Object>
3059 >        implements Spliterator<Map.Entry<K,V>> {
3060 >        EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3061 >        EntryIterator(Traverser<K,V,Object> it) {
3062 >            super(it);
3063 >        }
3064 >        public EntryIterator<K,V> split() {
3065 >            if (last != null || (next != null && nextVal == null))
3066 >                throw new IllegalStateException();
3067 >            return new EntryIterator<K,V>(this);
3068 >        }
3069 >
3070 >        @SuppressWarnings("unchecked") public final Map.Entry<K,V> next() {
3071 >            Object v;
3072 >            if ((v = nextVal) == null && (v = advance()) == null)
3073 >                throw new NoSuchElementException();
3074 >            Object k = nextKey;
3075 >            nextVal = null;
3076 >            return new MapEntry<K,V>((K)k, (V)v, map);
3077          }
3078      }
3079  
3080      /**
3081 <     * Custom Entry class used by EntryIterator.next(), that relays
1401 <     * setValue changes to the underlying map.
3081 >     * Exported Entry for iterators
3082       */
3083 <    final class WriteThroughEntry extends AbstractMap.SimpleEntry<K,V> {
3084 <        @SuppressWarnings("unchecked")
3085 <        WriteThroughEntry(Object k, Object v) {
3086 <            super((K)k, (V)v);
3083 >    static final class MapEntry<K,V> implements Map.Entry<K, V> {
3084 >        final K key; // non-null
3085 >        V val;       // non-null
3086 >        final ConcurrentHashMapV8<K, V> map;
3087 >        MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
3088 >            this.key = key;
3089 >            this.val = val;
3090 >            this.map = map;
3091 >        }
3092 >        public final K getKey()       { return key; }
3093 >        public final V getValue()     { return val; }
3094 >        public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3095 >        public final String toString(){ return key + "=" + val; }
3096 >
3097 >        public final boolean equals(Object o) {
3098 >            Object k, v; Map.Entry<?,?> e;
3099 >            return ((o instanceof Map.Entry) &&
3100 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3101 >                    (v = e.getValue()) != null &&
3102 >                    (k == key || k.equals(key)) &&
3103 >                    (v == val || v.equals(val)));
3104          }
3105  
3106          /**
3107           * Sets our entry's value and writes through to the map. The
3108 <         * value to return is somewhat arbitrary here. Since a
3109 <         * WriteThroughEntry does not necessarily track asynchronous
3110 <         * changes, the most recent "previous" value could be
3111 <         * different from what we return (or could even have been
3112 <         * removed in which case the put will re-establish). We do not
1416 <         * and cannot guarantee more.
3108 >         * value to return is somewhat arbitrary here. Since we do not
3109 >         * necessarily track asynchronous changes, the most recent
3110 >         * "previous" value could be different from what we return (or
3111 >         * could even have been removed in which case the put will
3112 >         * re-establish). We do not and cannot guarantee more.
3113           */
3114 <        public V setValue(V value) {
3114 >        public final V setValue(V value) {
3115              if (value == null) throw new NullPointerException();
3116 <            V v = super.setValue(value);
3117 <            ConcurrentHashMapV8.this.put(getKey(), value);
3116 >            V v = val;
3117 >            val = value;
3118 >            map.put(key, value);
3119              return v;
3120          }
3121      }
3122  
3123 <    final class KeyIterator extends HashIterator
1427 <        implements Iterator<K>, Enumeration<K> {
1428 <        @SuppressWarnings("unchecked")
1429 <        public final K next()        { return (K)super.nextKey(); }
1430 <        @SuppressWarnings("unchecked")
1431 <        public final K nextElement() { return (K)super.nextKey(); }
1432 <    }
1433 <
1434 <    final class ValueIterator extends HashIterator
1435 <        implements Iterator<V>, Enumeration<V> {
1436 <        @SuppressWarnings("unchecked")
1437 <        public final V next()        { return (V)super.nextValue(); }
1438 <        @SuppressWarnings("unchecked")
1439 <        public final V nextElement() { return (V)super.nextValue(); }
1440 <    }
3123 >    /* ----------------Views -------------- */
3124  
3125 <    final class EntryIterator extends HashIterator
3126 <        implements Iterator<Entry<K,V>> {
3127 <        public final Map.Entry<K,V> next() { return super.nextEntry(); }
3128 <    }
3125 >    /**
3126 >     * Base class for views.
3127 >     */
3128 >    static abstract class CHMView<K, V> {
3129 >        final ConcurrentHashMapV8<K, V> map;
3130 >        CHMView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
3131 >        public final int size()                 { return map.size(); }
3132 >        public final boolean isEmpty()          { return map.isEmpty(); }
3133 >        public final void clear()               { map.clear(); }
3134 >
3135 >        // implementations below rely on concrete classes supplying these
3136 >        abstract public Iterator<?> iterator();
3137 >        abstract public boolean contains(Object o);
3138 >        abstract public boolean remove(Object o);
3139 >
3140 >        private static final String oomeMsg = "Required array size too large";
3141 >
3142 >        public final Object[] toArray() {
3143 >            long sz = map.mappingCount();
3144 >            if (sz > (long)(MAX_ARRAY_SIZE))
3145 >                throw new OutOfMemoryError(oomeMsg);
3146 >            int n = (int)sz;
3147 >            Object[] r = new Object[n];
3148 >            int i = 0;
3149 >            Iterator<?> it = iterator();
3150 >            while (it.hasNext()) {
3151 >                if (i == n) {
3152 >                    if (n >= MAX_ARRAY_SIZE)
3153 >                        throw new OutOfMemoryError(oomeMsg);
3154 >                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3155 >                        n = MAX_ARRAY_SIZE;
3156 >                    else
3157 >                        n += (n >>> 1) + 1;
3158 >                    r = Arrays.copyOf(r, n);
3159 >                }
3160 >                r[i++] = it.next();
3161 >            }
3162 >            return (i == n) ? r : Arrays.copyOf(r, i);
3163 >        }
3164  
3165 <    final class KeySet extends AbstractSet<K> {
3166 <        public int size() {
3167 <            return ConcurrentHashMapV8.this.size();
3165 >        @SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
3166 >            long sz = map.mappingCount();
3167 >            if (sz > (long)(MAX_ARRAY_SIZE))
3168 >                throw new OutOfMemoryError(oomeMsg);
3169 >            int m = (int)sz;
3170 >            T[] r = (a.length >= m) ? a :
3171 >                (T[])java.lang.reflect.Array
3172 >                .newInstance(a.getClass().getComponentType(), m);
3173 >            int n = r.length;
3174 >            int i = 0;
3175 >            Iterator<?> it = iterator();
3176 >            while (it.hasNext()) {
3177 >                if (i == n) {
3178 >                    if (n >= MAX_ARRAY_SIZE)
3179 >                        throw new OutOfMemoryError(oomeMsg);
3180 >                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3181 >                        n = MAX_ARRAY_SIZE;
3182 >                    else
3183 >                        n += (n >>> 1) + 1;
3184 >                    r = Arrays.copyOf(r, n);
3185 >                }
3186 >                r[i++] = (T)it.next();
3187 >            }
3188 >            if (a == r && i < n) {
3189 >                r[i] = null; // null-terminate
3190 >                return r;
3191 >            }
3192 >            return (i == n) ? r : Arrays.copyOf(r, i);
3193          }
3194 <        public boolean isEmpty() {
3195 <            return ConcurrentHashMapV8.this.isEmpty();
3194 >
3195 >        public final int hashCode() {
3196 >            int h = 0;
3197 >            for (Iterator<?> it = iterator(); it.hasNext();)
3198 >                h += it.next().hashCode();
3199 >            return h;
3200          }
3201 <        public void clear() {
3202 <            ConcurrentHashMapV8.this.clear();
3201 >
3202 >        public final String toString() {
3203 >            StringBuilder sb = new StringBuilder();
3204 >            sb.append('[');
3205 >            Iterator<?> it = iterator();
3206 >            if (it.hasNext()) {
3207 >                for (;;) {
3208 >                    Object e = it.next();
3209 >                    sb.append(e == this ? "(this Collection)" : e);
3210 >                    if (!it.hasNext())
3211 >                        break;
3212 >                    sb.append(',').append(' ');
3213 >                }
3214 >            }
3215 >            return sb.append(']').toString();
3216          }
3217 <        public Iterator<K> iterator() {
3218 <            return new KeyIterator();
3217 >
3218 >        public final boolean containsAll(Collection<?> c) {
3219 >            if (c != this) {
3220 >                for (Iterator<?> it = c.iterator(); it.hasNext();) {
3221 >                    Object e = it.next();
3222 >                    if (e == null || !contains(e))
3223 >                        return false;
3224 >                }
3225 >            }
3226 >            return true;
3227          }
3228 <        public boolean contains(Object o) {
3229 <            return ConcurrentHashMapV8.this.containsKey(o);
3228 >
3229 >        public final boolean removeAll(Collection<?> c) {
3230 >            boolean modified = false;
3231 >            for (Iterator<?> it = iterator(); it.hasNext();) {
3232 >                if (c.contains(it.next())) {
3233 >                    it.remove();
3234 >                    modified = true;
3235 >                }
3236 >            }
3237 >            return modified;
3238          }
3239 <        public boolean remove(Object o) {
3240 <            return ConcurrentHashMapV8.this.remove(o) != null;
3239 >
3240 >        public final boolean retainAll(Collection<?> c) {
3241 >            boolean modified = false;
3242 >            for (Iterator<?> it = iterator(); it.hasNext();) {
3243 >                if (!c.contains(it.next())) {
3244 >                    it.remove();
3245 >                    modified = true;
3246 >                }
3247 >            }
3248 >            return modified;
3249          }
3250 +
3251      }
3252  
3253 <    final class Values extends AbstractCollection<V> {
3254 <        public int size() {
3255 <            return ConcurrentHashMapV8.this.size();
3253 >    static final class KeySet<K,V> extends CHMView<K,V> implements Set<K> {
3254 >        KeySet(ConcurrentHashMapV8<K, V> map)  {
3255 >            super(map);
3256          }
3257 <        public boolean isEmpty() {
3258 <            return ConcurrentHashMapV8.this.isEmpty();
3257 >        public final boolean contains(Object o) { return map.containsKey(o); }
3258 >        public final boolean remove(Object o)   { return map.remove(o) != null; }
3259 >        public final Iterator<K> iterator() {
3260 >            return new KeyIterator<K,V>(map);
3261          }
3262 <        public void clear() {
3263 <            ConcurrentHashMapV8.this.clear();
3262 >        public final boolean add(K e) {
3263 >            throw new UnsupportedOperationException();
3264          }
3265 <        public Iterator<V> iterator() {
3266 <            return new ValueIterator();
3265 >        public final boolean addAll(Collection<? extends K> c) {
3266 >            throw new UnsupportedOperationException();
3267          }
3268 <        public boolean contains(Object o) {
3269 <            return ConcurrentHashMapV8.this.containsValue(o);
3268 >        public boolean equals(Object o) {
3269 >            Set<?> c;
3270 >            return ((o instanceof Set) &&
3271 >                    ((c = (Set<?>)o) == this ||
3272 >                     (containsAll(c) && c.containsAll(this))));
3273          }
3274      }
3275  
3276 <    final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3277 <        public int size() {
3278 <            return ConcurrentHashMapV8.this.size();
3279 <        }
3280 <        public boolean isEmpty() {
3281 <            return ConcurrentHashMapV8.this.isEmpty();
3276 >
3277 >    static final class Values<K,V> extends CHMView<K,V>
3278 >        implements Collection<V> {
3279 >        Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3280 >        public final boolean contains(Object o) { return map.containsValue(o); }
3281 >        public final boolean remove(Object o) {
3282 >            if (o != null) {
3283 >                Iterator<V> it = new ValueIterator<K,V>(map);
3284 >                while (it.hasNext()) {
3285 >                    if (o.equals(it.next())) {
3286 >                        it.remove();
3287 >                        return true;
3288 >                    }
3289 >                }
3290 >            }
3291 >            return false;
3292          }
3293 <        public void clear() {
3294 <            ConcurrentHashMapV8.this.clear();
3293 >        public final Iterator<V> iterator() {
3294 >            return new ValueIterator<K,V>(map);
3295          }
3296 <        public Iterator<Map.Entry<K,V>> iterator() {
3297 <            return new EntryIterator();
3296 >        public final boolean add(V e) {
3297 >            throw new UnsupportedOperationException();
3298          }
3299 <        public boolean contains(Object o) {
3300 <            if (!(o instanceof Map.Entry))
1501 <                return false;
1502 <            Map.Entry<?,?> e = (Map.Entry<?,?>)o;
1503 <            V v = ConcurrentHashMapV8.this.get(e.getKey());
1504 <            return v != null && v.equals(e.getValue());
3299 >        public final boolean addAll(Collection<? extends V> c) {
3300 >            throw new UnsupportedOperationException();
3301          }
3302 <        public boolean remove(Object o) {
3303 <            if (!(o instanceof Map.Entry))
3304 <                return false;
3305 <            Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3306 <            return ConcurrentHashMapV8.this.remove(e.getKey(), e.getValue());
3302 >
3303 >    }
3304 >
3305 >    static final class EntrySet<K,V> extends CHMView<K,V>
3306 >        implements Set<Map.Entry<K,V>> {
3307 >        EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3308 >        public final boolean contains(Object o) {
3309 >            Object k, v, r; Map.Entry<?,?> e;
3310 >            return ((o instanceof Map.Entry) &&
3311 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3312 >                    (r = map.get(k)) != null &&
3313 >                    (v = e.getValue()) != null &&
3314 >                    (v == r || v.equals(r)));
3315 >        }
3316 >        public final boolean remove(Object o) {
3317 >            Object k, v; Map.Entry<?,?> e;
3318 >            return ((o instanceof Map.Entry) &&
3319 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3320 >                    (v = e.getValue()) != null &&
3321 >                    map.remove(k, v));
3322 >        }
3323 >        public final Iterator<Map.Entry<K,V>> iterator() {
3324 >            return new EntryIterator<K,V>(map);
3325 >        }
3326 >        public final boolean add(Entry<K,V> e) {
3327 >            throw new UnsupportedOperationException();
3328 >        }
3329 >        public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3330 >            throw new UnsupportedOperationException();
3331 >        }
3332 >        public boolean equals(Object o) {
3333 >            Set<?> c;
3334 >            return ((o instanceof Set) &&
3335 >                    ((c = (Set<?>)o) == this ||
3336 >                     (containsAll(c) && c.containsAll(this))));
3337          }
3338      }
3339  
3340      /* ---------------- Serialization Support -------------- */
3341  
3342      /**
3343 <     * Helper class used in previous version, declared for the sake of
3344 <     * serialization compatibility
3343 >     * Stripped-down version of helper class used in previous version,
3344 >     * declared for the sake of serialization compatibility
3345       */
3346 <    static class Segment<K,V> extends java.util.concurrent.locks.ReentrantLock
1521 <        implements Serializable {
3346 >    static class Segment<K,V> implements Serializable {
3347          private static final long serialVersionUID = 2249069246763182397L;
3348          final float loadFactor;
3349          Segment(float lf) { this.loadFactor = lf; }
# Line 1533 | Line 3358 | public class ConcurrentHashMapV8<K, V>
3358       * for each key-value mapping, followed by a null pair.
3359       * The key-value mappings are emitted in no particular order.
3360       */
3361 <    @SuppressWarnings("unchecked")
3362 <    private void writeObject(java.io.ObjectOutputStream s)
1538 <            throws java.io.IOException {
3361 >    @SuppressWarnings("unchecked") private void writeObject(java.io.ObjectOutputStream s)
3362 >        throws java.io.IOException {
3363          if (segments == null) { // for serialization compatibility
3364              segments = (Segment<K,V>[])
3365                  new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3366              for (int i = 0; i < segments.length; ++i)
3367 <                segments[i] = new Segment<K,V>(loadFactor);
3367 >                segments[i] = new Segment<K,V>(LOAD_FACTOR);
3368          }
3369          s.defaultWriteObject();
3370 <        new HashIterator().writeEntries(s);
3370 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3371 >        Object v;
3372 >        while ((v = it.advance()) != null) {
3373 >            s.writeObject(it.nextKey);
3374 >            s.writeObject(v);
3375 >        }
3376          s.writeObject(null);
3377          s.writeObject(null);
3378          segments = null; // throw away
3379      }
3380  
3381      /**
3382 <     * Reconstitutes the  instance from a
1554 <     * stream (i.e., deserializes it).
3382 >     * Reconstitutes the instance from a stream (that is, deserializes it).
3383       * @param s the stream
3384       */
3385 <    @SuppressWarnings("unchecked")
3386 <    private void readObject(java.io.ObjectInputStream s)
1559 <            throws java.io.IOException, ClassNotFoundException {
3385 >    @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s)
3386 >        throws java.io.IOException, ClassNotFoundException {
3387          s.defaultReadObject();
1561        // find load factor in a segment, if one exists
1562        if (segments != null && segments.length != 0)
1563            this.loadFactor = segments[0].loadFactor;
1564        else
1565            this.loadFactor = DEFAULT_LOAD_FACTOR;
1566        this.initCap = DEFAULT_CAPACITY;
1567        LongAdder ct = new LongAdder(); // force final field write
1568        UNSAFE.putObjectVolatile(this, counterOffset, ct);
3388          this.segments = null; // unneeded
3389 +        // initialize transient final field
3390 +        UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
3391  
3392 <        // Read the keys and values, and put the mappings in the table
3392 >        // Create all nodes, then place in table once size is known
3393 >        long size = 0L;
3394 >        Node p = null;
3395          for (;;) {
3396 <            K key = (K) s.readObject();
3397 <            V value = (V) s.readObject();
3398 <            if (key == null)
3396 >            K k = (K) s.readObject();
3397 >            V v = (V) s.readObject();
3398 >            if (k != null && v != null) {
3399 >                int h = spread(k.hashCode());
3400 >                p = new Node(h, k, v, p);
3401 >                ++size;
3402 >            }
3403 >            else
3404                  break;
3405 <            put(key, value);
3405 >        }
3406 >        if (p != null) {
3407 >            boolean init = false;
3408 >            int n;
3409 >            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3410 >                n = MAXIMUM_CAPACITY;
3411 >            else {
3412 >                int sz = (int)size;
3413 >                n = tableSizeFor(sz + (sz >>> 1) + 1);
3414 >            }
3415 >            int sc = sizeCtl;
3416 >            boolean collide = false;
3417 >            if (n > sc &&
3418 >                UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3419 >                try {
3420 >                    if (table == null) {
3421 >                        init = true;
3422 >                        Node[] tab = new Node[n];
3423 >                        int mask = n - 1;
3424 >                        while (p != null) {
3425 >                            int j = p.hash & mask;
3426 >                            Node next = p.next;
3427 >                            Node q = p.next = tabAt(tab, j);
3428 >                            setTabAt(tab, j, p);
3429 >                            if (!collide && q != null && q.hash == p.hash)
3430 >                                collide = true;
3431 >                            p = next;
3432 >                        }
3433 >                        table = tab;
3434 >                        counter.add(size);
3435 >                        sc = n - (n >>> 2);
3436 >                    }
3437 >                } finally {
3438 >                    sizeCtl = sc;
3439 >                }
3440 >                if (collide) { // rescan and convert to TreeBins
3441 >                    Node[] tab = table;
3442 >                    for (int i = 0; i < tab.length; ++i) {
3443 >                        int c = 0;
3444 >                        for (Node e = tabAt(tab, i); e != null; e = e.next) {
3445 >                            if (++c > TREE_THRESHOLD &&
3446 >                                (e.key instanceof Comparable)) {
3447 >                                replaceWithTreeBin(tab, i, e.key);
3448 >                                break;
3449 >                            }
3450 >                        }
3451 >                    }
3452 >                }
3453 >            }
3454 >            if (!init) { // Can only happen if unsafely published.
3455 >                while (p != null) {
3456 >                    internalPut(p.key, p.val);
3457 >                    p = p.next;
3458 >                }
3459 >            }
3460 >        }
3461 >    }
3462 >
3463 >
3464 >    // -------------------------------------------------------
3465 >
3466 >    // Sams
3467 >    /** Interface describing a void action of one argument */
3468 >    public interface Action<A> { void apply(A a); }
3469 >    /** Interface describing a void action of two arguments */
3470 >    public interface BiAction<A,B> { void apply(A a, B b); }
3471 >    /** Interface describing a function of one argument */
3472 >    public interface Fun<A,T> { T apply(A a); }
3473 >    /** Interface describing a function of two arguments */
3474 >    public interface BiFun<A,B,T> { T apply(A a, B b); }
3475 >    /** Interface describing a function of no arguments */
3476 >    public interface Generator<T> { T apply(); }
3477 >    /** Interface describing a function mapping its argument to a double */
3478 >    public interface ObjectToDouble<A> { double apply(A a); }
3479 >    /** Interface describing a function mapping its argument to a long */
3480 >    public interface ObjectToLong<A> { long apply(A a); }
3481 >    /** Interface describing a function mapping its argument to an int */
3482 >    public interface ObjectToInt<A> {int apply(A a); }
3483 >    /** Interface describing a function mapping two arguments to a double */
3484 >    public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
3485 >    /** Interface describing a function mapping two arguments to a long */
3486 >    public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
3487 >    /** Interface describing a function mapping two arguments to an int */
3488 >    public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }
3489 >    /** Interface describing a function mapping a double to a double */
3490 >    public interface DoubleToDouble { double apply(double a); }
3491 >    /** Interface describing a function mapping a long to a long */
3492 >    public interface LongToLong { long apply(long a); }
3493 >    /** Interface describing a function mapping an int to an int */
3494 >    public interface IntToInt { int apply(int a); }
3495 >    /** Interface describing a function mapping two doubles to a double */
3496 >    public interface DoubleByDoubleToDouble { double apply(double a, double b); }
3497 >    /** Interface describing a function mapping two longs to a long */
3498 >    public interface LongByLongToLong { long apply(long a, long b); }
3499 >    /** Interface describing a function mapping two ints to an int */
3500 >    public interface IntByIntToInt { int apply(int a, int b); }
3501 >
3502 >
3503 >    // -------------------------------------------------------
3504 >
3505 >    /**
3506 >     * Returns an extended {@link Parallel} view of this map using the
3507 >     * given executor for bulk parallel operations.
3508 >     *
3509 >     * @param executor the executor
3510 >     * @return a parallel view
3511 >     */
3512 >    public Parallel parallel(ForkJoinPool executor)  {
3513 >        return new Parallel(executor);
3514 >    }
3515 >
3516 >    /**
3517 >     * An extended view of a ConcurrentHashMap supporting bulk
3518 >     * parallel operations. These operations are designed to be
3519 >     * safely, and often sensibly, applied even with maps that are
3520 >     * being concurrently updated by other threads; for example, when
3521 >     * computing a snapshot summary of the values in a shared
3522 >     * registry.  There are three kinds of operation, each with four
3523 >     * forms, accepting functions with Keys, Values, Entries, and
3524 >     * (Key, Value) arguments and/or return values. Because the
3525 >     * elements of a ConcurrentHashMap are not ordered in any
3526 >     * particular way, and may be processed in different orders in
3527 >     * different parallel executions, the correctness of supplied
3528 >     * functions should not depend on any ordering, or on any other
3529 >     * objects or values that may transiently change while computation
3530 >     * is in progress; and except for forEach actions, should ideally
3531 >     * be side-effect-free.
3532 >     *
3533 >     * <ul>
3534 >     * <li> forEach: Perform a given action on each element.
3535 >     * A variant form applies a given transformation on each element
3536 >     * before performing the action.</li>
3537 >     *
3538 >     * <li> search: Return the first available non-null result of
3539 >     * applying a given function on each element; skipping further
3540 >     * search when a result is found.</li>
3541 >     *
3542 >     * <li> reduce: Accumulate each element.  The supplied reduction
3543 >     * function cannot rely on ordering (more formally, it should be
3544 >     * both associative and commutative).  There are five variants:
3545 >     *
3546 >     * <ul>
3547 >     *
3548 >     * <li> Plain reductions. (There is not a form of this method for
3549 >     * (key, value) function arguments since there is no corresponding
3550 >     * return type.)</li>
3551 >     *
3552 >     * <li> Mapped reductions that accumulate the results of a given
3553 >     * function applied to each element.</li>
3554 >     *
3555 >     * <li> Reductions to scalar doubles, longs, and ints, using a
3556 >     * given basis value.</li>
3557 >     *
3558 >     * </li>
3559 >     * </ul>
3560 >     * </ul>
3561 >     *
3562 >     * <p>The concurrency properties of the bulk operations follow
3563 >     * from those of ConcurrentHashMap: Any non-null result returned
3564 >     * from {@code get(key)} and related access methods bears a
3565 >     * happens-before relation with the associated insertion or
3566 >     * update.  The result of any bulk operation reflects the
3567 >     * composition of these per-element relations (but is not
3568 >     * necessarily atomic with respect to the map as a whole unless it
3569 >     * is somehow known to be quiescent).  Conversely, because keys
3570 >     * and values in the map are never null, null serves as a reliable
3571 >     * atomic indicator of the current lack of any result.  To
3572 >     * maintain this property, null serves as an implicit basis for
3573 >     * all non-scalar reduction operations. For the double, long, and
3574 >     * int versions, the basis should be one that, when combined with
3575 >     * any other value, returns that other value (more formally, it
3576 >     * should be the identity element for the reduction). Most common
3577 >     * reductions have these properties; for example, computing a sum
3578 >     * with basis 0 or a minimum with basis MAX_VALUE.
3579 >     *
3580 >     * <p>Search and transformation functions provided as arguments
3581 >     * should similarly return null to indicate the lack of any result
3582 >     * (in which case it is not used). In the case of mapped
3583 >     * reductions, this also enables transformations to serve as
3584 >     * filters, returning null (or, in the case of primitive
3585 >     * specializations, the identity basis) if the element should not
3586 >     * be combined. You can create compound transformations and
3587 >     * filterings by composing them yourself under this "null means
3588 >     * there is nothing there now" rule before using them in search or
3589 >     * reduce operations.
3590 >     *
3591 >     * <p>Methods accepting and/or returning Entry arguments maintain
3592 >     * key-value associations. They may be useful for example when
3593 >     * finding the key for the greatest value. Note that "plain" Entry
3594 >     * arguments can be supplied using {@code new
3595 >     * AbstractMap.SimpleEntry(k,v)}.
3596 >     *
3597 >     * <p> Bulk operations may complete abruptly, throwing an
3598 >     * exception encountered in the application of a supplied
3599 >     * function. Bear in mind when handling such exceptions that other
3600 >     * concurrently executing functions could also have thrown
3601 >     * exceptions, or would have done so if the first exception had
3602 >     * not occurred.
3603 >     *
3604 >     * <p>Parallel speedups compared to sequential processing are
3605 >     * common but not guaranteed.  Operations involving brief
3606 >     * functions on small maps may execute more slowly than sequential
3607 >     * loops if the underlying work to parallelize the computation is
3608 >     * more expensive than the computation itself. Similarly,
3609 >     * parallelization may not lead to much actual parallelism if all
3610 >     * processors are busy performing unrelated tasks.
3611 >     *
3612 >     * <p> All arguments to all task methods must be non-null.
3613 >     *
3614 >     * <p><em>jsr166e note: During transition, this class
3615 >     * uses nested functional interfaces with different names but the
3616 >     * same forms as those expected for JDK8.<em>
3617 >     */
3618 >    public class Parallel {
3619 >        final ForkJoinPool fjp;
3620 >
3621 >        /**
3622 >         * Returns an extended view of this map using the given
3623 >         * executor for bulk parallel operations.
3624 >         *
3625 >         * @param executor the executor
3626 >         */
3627 >        public Parallel(ForkJoinPool executor)  {
3628 >            this.fjp = executor;
3629 >        }
3630 >
3631 >        /**
3632 >         * Performs the given action for each (key, value).
3633 >         *
3634 >         * @param action the action
3635 >         */
3636 >        public void forEach(BiAction<K,V> action) {
3637 >            fjp.invoke(ForkJoinTasks.forEach
3638 >                       (ConcurrentHashMapV8.this, action));
3639 >        }
3640 >
3641 >        /**
3642 >         * Performs the given action for each non-null transformation
3643 >         * of each (key, value).
3644 >         *
3645 >         * @param transformer a function returning the transformation
3646 >         * for an element, or null of there is no transformation (in
3647 >         * which case the action is not applied).
3648 >         * @param action the action
3649 >         */
3650 >        public <U> void forEach(BiFun<? super K, ? super V, ? extends U> transformer,
3651 >                                Action<U> action) {
3652 >            fjp.invoke(ForkJoinTasks.forEach
3653 >                       (ConcurrentHashMapV8.this, transformer, action));
3654 >        }
3655 >
3656 >        /**
3657 >         * Returns a non-null result from applying the given search
3658 >         * function on each (key, value), or null if none.  Upon
3659 >         * success, further element processing is suppressed and the
3660 >         * results of any other parallel invocations of the search
3661 >         * function are ignored.
3662 >         *
3663 >         * @param searchFunction a function returning a non-null
3664 >         * result on success, else null
3665 >         * @return a non-null result from applying the given search
3666 >         * function on each (key, value), or null if none
3667 >         */
3668 >        public <U> U search(BiFun<? super K, ? super V, ? extends U> searchFunction) {
3669 >            return fjp.invoke(ForkJoinTasks.search
3670 >                              (ConcurrentHashMapV8.this, searchFunction));
3671 >        }
3672 >
3673 >        /**
3674 >         * Returns the result of accumulating the given transformation
3675 >         * of all (key, value) pairs using the given reducer to
3676 >         * combine values, or null if none.
3677 >         *
3678 >         * @param transformer a function returning the transformation
3679 >         * for an element, or null of there is no transformation (in
3680 >         * which case it is not combined).
3681 >         * @param reducer a commutative associative combining function
3682 >         * @return the result of accumulating the given transformation
3683 >         * of all (key, value) pairs
3684 >         */
3685 >        public <U> U reduce(BiFun<? super K, ? super V, ? extends U> transformer,
3686 >                            BiFun<? super U, ? super U, ? extends U> reducer) {
3687 >            return fjp.invoke(ForkJoinTasks.reduce
3688 >                              (ConcurrentHashMapV8.this, transformer, reducer));
3689 >        }
3690 >
3691 >        /**
3692 >         * Returns the result of accumulating the given transformation
3693 >         * of all (key, value) pairs using the given reducer to
3694 >         * combine values, and the given basis as an identity value.
3695 >         *
3696 >         * @param transformer a function returning the transformation
3697 >         * for an element
3698 >         * @param basis the identity (initial default value) for the reduction
3699 >         * @param reducer a commutative associative combining function
3700 >         * @return the result of accumulating the given transformation
3701 >         * of all (key, value) pairs
3702 >         */
3703 >        public double reduceToDouble(ObjectByObjectToDouble<? super K, ? super V> transformer,
3704 >                                     double basis,
3705 >                                     DoubleByDoubleToDouble reducer) {
3706 >            return fjp.invoke(ForkJoinTasks.reduceToDouble
3707 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3708 >        }
3709 >
3710 >        /**
3711 >         * Returns the result of accumulating the given transformation
3712 >         * of all (key, value) pairs using the given reducer to
3713 >         * combine values, and the given basis as an identity value.
3714 >         *
3715 >         * @param transformer a function returning the transformation
3716 >         * for an element
3717 >         * @param basis the identity (initial default value) for the reduction
3718 >         * @param reducer a commutative associative combining function
3719 >         * @return the result of accumulating the given transformation
3720 >         * of all (key, value) pairs
3721 >         */
3722 >        public long reduceToLong(ObjectByObjectToLong<? super K, ? super V> transformer,
3723 >                                 long basis,
3724 >                                 LongByLongToLong reducer) {
3725 >            return fjp.invoke(ForkJoinTasks.reduceToLong
3726 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3727 >        }
3728 >
3729 >        /**
3730 >         * Returns the result of accumulating the given transformation
3731 >         * of all (key, value) pairs using the given reducer to
3732 >         * combine values, and the given basis as an identity value.
3733 >         *
3734 >         * @param transformer a function returning the transformation
3735 >         * for an element
3736 >         * @param basis the identity (initial default value) for the reduction
3737 >         * @param reducer a commutative associative combining function
3738 >         * @return the result of accumulating the given transformation
3739 >         * of all (key, value) pairs
3740 >         */
3741 >        public int reduceToInt(ObjectByObjectToInt<? super K, ? super V> transformer,
3742 >                               int basis,
3743 >                               IntByIntToInt reducer) {
3744 >            return fjp.invoke(ForkJoinTasks.reduceToInt
3745 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3746 >        }
3747 >
3748 >        /**
3749 >         * Performs the given action for each key.
3750 >         *
3751 >         * @param action the action
3752 >         */
3753 >        public void forEachKey(Action<K> action) {
3754 >            fjp.invoke(ForkJoinTasks.forEachKey
3755 >                       (ConcurrentHashMapV8.this, action));
3756 >        }
3757 >
3758 >        /**
3759 >         * Performs the given action for each non-null transformation
3760 >         * of each key.
3761 >         *
3762 >         * @param transformer a function returning the transformation
3763 >         * for an element, or null of there is no transformation (in
3764 >         * which case the action is not applied).
3765 >         * @param action the action
3766 >         */
3767 >        public <U> void forEachKey(Fun<? super K, ? extends U> transformer,
3768 >                                   Action<U> action) {
3769 >            fjp.invoke(ForkJoinTasks.forEachKey
3770 >                       (ConcurrentHashMapV8.this, transformer, action));
3771 >        }
3772 >
3773 >        /**
3774 >         * Returns a non-null result from applying the given search
3775 >         * function on each key, or null if none. Upon success,
3776 >         * further element processing is suppressed and the results of
3777 >         * any other parallel invocations of the search function are
3778 >         * ignored.
3779 >         *
3780 >         * @param searchFunction a function returning a non-null
3781 >         * result on success, else null
3782 >         * @return a non-null result from applying the given search
3783 >         * function on each key, or null if none
3784 >         */
3785 >        public <U> U searchKeys(Fun<? super K, ? extends U> searchFunction) {
3786 >            return fjp.invoke(ForkJoinTasks.searchKeys
3787 >                              (ConcurrentHashMapV8.this, searchFunction));
3788 >        }
3789 >
3790 >        /**
3791 >         * Returns the result of accumulating all keys using the given
3792 >         * reducer to combine values, or null if none.
3793 >         *
3794 >         * @param reducer a commutative associative combining function
3795 >         * @return the result of accumulating all keys using the given
3796 >         * reducer to combine values, or null if none
3797 >         */
3798 >        public K reduceKeys(BiFun<? super K, ? super K, ? extends K> reducer) {
3799 >            return fjp.invoke(ForkJoinTasks.reduceKeys
3800 >                              (ConcurrentHashMapV8.this, reducer));
3801 >        }
3802 >
3803 >        /**
3804 >         * Returns the result of accumulating the given transformation
3805 >         * of all keys using the given reducer to combine values, or
3806 >         * null if none.
3807 >         *
3808 >         * @param transformer a function returning the transformation
3809 >         * for an element, or null of there is no transformation (in
3810 >         * which case it is not combined).
3811 >         * @param reducer a commutative associative combining function
3812 >         * @return the result of accumulating the given transformation
3813 >         * of all keys
3814 >         */
3815 >        public <U> U reduceKeys(Fun<? super K, ? extends U> transformer,
3816 >                                BiFun<? super U, ? super U, ? extends U> reducer) {
3817 >            return fjp.invoke(ForkJoinTasks.reduceKeys
3818 >                              (ConcurrentHashMapV8.this, transformer, reducer));
3819 >        }
3820 >
3821 >        /**
3822 >         * Returns the result of accumulating the given transformation
3823 >         * of all keys using the given reducer to combine values, and
3824 >         * the given basis as an identity value.
3825 >         *
3826 >         * @param transformer a function returning the transformation
3827 >         * for an element
3828 >         * @param basis the identity (initial default value) for the reduction
3829 >         * @param reducer a commutative associative combining function
3830 >         * @return  the result of accumulating the given transformation
3831 >         * of all keys
3832 >         */
3833 >        public double reduceKeysToDouble(ObjectToDouble<? super K> transformer,
3834 >                                         double basis,
3835 >                                         DoubleByDoubleToDouble reducer) {
3836 >            return fjp.invoke(ForkJoinTasks.reduceKeysToDouble
3837 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3838 >        }
3839 >
3840 >        /**
3841 >         * Returns the result of accumulating the given transformation
3842 >         * of all keys using the given reducer to combine values, and
3843 >         * the given basis as an identity value.
3844 >         *
3845 >         * @param transformer a function returning the transformation
3846 >         * for an element
3847 >         * @param basis the identity (initial default value) for the reduction
3848 >         * @param reducer a commutative associative combining function
3849 >         * @return the result of accumulating the given transformation
3850 >         * of all keys
3851 >         */
3852 >        public long reduceKeysToLong(ObjectToLong<? super K> transformer,
3853 >                                     long basis,
3854 >                                     LongByLongToLong reducer) {
3855 >            return fjp.invoke(ForkJoinTasks.reduceKeysToLong
3856 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3857 >        }
3858 >
3859 >        /**
3860 >         * Returns the result of accumulating the given transformation
3861 >         * of all keys using the given reducer to combine values, and
3862 >         * the given basis as an identity value.
3863 >         *
3864 >         * @param transformer a function returning the transformation
3865 >         * for an element
3866 >         * @param basis the identity (initial default value) for the reduction
3867 >         * @param reducer a commutative associative combining function
3868 >         * @return the result of accumulating the given transformation
3869 >         * of all keys
3870 >         */
3871 >        public int reduceKeysToInt(ObjectToInt<? super K> transformer,
3872 >                                   int basis,
3873 >                                   IntByIntToInt reducer) {
3874 >            return fjp.invoke(ForkJoinTasks.reduceKeysToInt
3875 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3876 >        }
3877 >
3878 >        /**
3879 >         * Performs the given action for each value.
3880 >         *
3881 >         * @param action the action
3882 >         */
3883 >        public void forEachValue(Action<V> action) {
3884 >            fjp.invoke(ForkJoinTasks.forEachValue
3885 >                       (ConcurrentHashMapV8.this, action));
3886 >        }
3887 >
3888 >        /**
3889 >         * Performs the given action for each non-null transformation
3890 >         * of each value.
3891 >         *
3892 >         * @param transformer a function returning the transformation
3893 >         * for an element, or null of there is no transformation (in
3894 >         * which case the action is not applied).
3895 >         */
3896 >        public <U> void forEachValue(Fun<? super V, ? extends U> transformer,
3897 >                                     Action<U> action) {
3898 >            fjp.invoke(ForkJoinTasks.forEachValue
3899 >                       (ConcurrentHashMapV8.this, transformer, action));
3900 >        }
3901 >
3902 >        /**
3903 >         * Returns a non-null result from applying the given search
3904 >         * function on each value, or null if none.  Upon success,
3905 >         * further element processing is suppressed and the results of
3906 >         * any other parallel invocations of the search function are
3907 >         * ignored.
3908 >         *
3909 >         * @param searchFunction a function returning a non-null
3910 >         * result on success, else null
3911 >         * @return a non-null result from applying the given search
3912 >         * function on each value, or null if none
3913 >         *
3914 >         */
3915 >        public <U> U searchValues(Fun<? super V, ? extends U> searchFunction) {
3916 >            return fjp.invoke(ForkJoinTasks.searchValues
3917 >                              (ConcurrentHashMapV8.this, searchFunction));
3918 >        }
3919 >
3920 >        /**
3921 >         * Returns the result of accumulating all values using the
3922 >         * given reducer to combine values, or null if none.
3923 >         *
3924 >         * @param reducer a commutative associative combining function
3925 >         * @return  the result of accumulating all values
3926 >         */
3927 >        public V reduceValues(BiFun<? super V, ? super V, ? extends V> reducer) {
3928 >            return fjp.invoke(ForkJoinTasks.reduceValues
3929 >                              (ConcurrentHashMapV8.this, reducer));
3930 >        }
3931 >
3932 >        /**
3933 >         * Returns the result of accumulating the given transformation
3934 >         * of all values using the given reducer to combine values, or
3935 >         * null if none.
3936 >         *
3937 >         * @param transformer a function returning the transformation
3938 >         * for an element, or null of there is no transformation (in
3939 >         * which case it is not combined).
3940 >         * @param reducer a commutative associative combining function
3941 >         * @return the result of accumulating the given transformation
3942 >         * of all values
3943 >         */
3944 >        public <U> U reduceValues(Fun<? super V, ? extends U> transformer,
3945 >                                  BiFun<? super U, ? super U, ? extends U> reducer) {
3946 >            return fjp.invoke(ForkJoinTasks.reduceValues
3947 >                              (ConcurrentHashMapV8.this, transformer, reducer));
3948 >        }
3949 >
3950 >        /**
3951 >         * Returns the result of accumulating the given transformation
3952 >         * of all values using the given reducer to combine values,
3953 >         * and the given basis as an identity value.
3954 >         *
3955 >         * @param transformer a function returning the transformation
3956 >         * for an element
3957 >         * @param basis the identity (initial default value) for the reduction
3958 >         * @param reducer a commutative associative combining function
3959 >         * @return the result of accumulating the given transformation
3960 >         * of all values
3961 >         */
3962 >        public double reduceValuesToDouble(ObjectToDouble<? super V> transformer,
3963 >                                           double basis,
3964 >                                           DoubleByDoubleToDouble reducer) {
3965 >            return fjp.invoke(ForkJoinTasks.reduceValuesToDouble
3966 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3967 >        }
3968 >
3969 >        /**
3970 >         * Returns the result of accumulating the given transformation
3971 >         * of all values using the given reducer to combine values,
3972 >         * and the given basis as an identity value.
3973 >         *
3974 >         * @param transformer a function returning the transformation
3975 >         * for an element
3976 >         * @param basis the identity (initial default value) for the reduction
3977 >         * @param reducer a commutative associative combining function
3978 >         * @return the result of accumulating the given transformation
3979 >         * of all values
3980 >         */
3981 >        public long reduceValuesToLong(ObjectToLong<? super V> transformer,
3982 >                                       long basis,
3983 >                                       LongByLongToLong reducer) {
3984 >            return fjp.invoke(ForkJoinTasks.reduceValuesToLong
3985 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
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 transformer a function returning the transformation
3994 >         * for an element
3995 >         * @param basis the identity (initial default value) for the reduction
3996 >         * @param reducer a commutative associative combining function
3997 >         * @return the result of accumulating the given transformation
3998 >         * of all values
3999 >         */
4000 >        public int reduceValuesToInt(ObjectToInt<? super V> transformer,
4001 >                                     int basis,
4002 >                                     IntByIntToInt reducer) {
4003 >            return fjp.invoke(ForkJoinTasks.reduceValuesToInt
4004 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4005 >        }
4006 >
4007 >        /**
4008 >         * Performs the given action for each entry.
4009 >         *
4010 >         * @param action the action
4011 >         */
4012 >        public void forEachEntry(Action<Map.Entry<K,V>> action) {
4013 >            fjp.invoke(ForkJoinTasks.forEachEntry
4014 >                       (ConcurrentHashMapV8.this, action));
4015 >        }
4016 >
4017 >        /**
4018 >         * Performs the given action for each non-null transformation
4019 >         * of each entry.
4020 >         *
4021 >         * @param transformer a function returning the transformation
4022 >         * for an element, or null of there is no transformation (in
4023 >         * which case the action is not applied).
4024 >         * @param action the action
4025 >         */
4026 >        public <U> void forEachEntry(Fun<Map.Entry<K,V>, ? extends U> transformer,
4027 >                                     Action<U> action) {
4028 >            fjp.invoke(ForkJoinTasks.forEachEntry
4029 >                       (ConcurrentHashMapV8.this, transformer, action));
4030 >        }
4031 >
4032 >        /**
4033 >         * Returns a non-null result from applying the given search
4034 >         * function on each entry, or null if none.  Upon success,
4035 >         * further element processing is suppressed and the results of
4036 >         * any other parallel invocations of the search function are
4037 >         * ignored.
4038 >         *
4039 >         * @param searchFunction a function returning a non-null
4040 >         * result on success, else null
4041 >         * @return a non-null result from applying the given search
4042 >         * function on each entry, or null if none
4043 >         */
4044 >        public <U> U searchEntries(Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4045 >            return fjp.invoke(ForkJoinTasks.searchEntries
4046 >                              (ConcurrentHashMapV8.this, searchFunction));
4047 >        }
4048 >
4049 >        /**
4050 >         * Returns the result of accumulating all entries using the
4051 >         * given reducer to combine values, or null if none.
4052 >         *
4053 >         * @param reducer a commutative associative combining function
4054 >         * @return the result of accumulating all entries
4055 >         */
4056 >        public Map.Entry<K,V> reduceEntries(BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4057 >            return fjp.invoke(ForkJoinTasks.reduceEntries
4058 >                              (ConcurrentHashMapV8.this, reducer));
4059 >        }
4060 >
4061 >        /**
4062 >         * Returns the result of accumulating the given transformation
4063 >         * of all entries using the given reducer to combine values,
4064 >         * or null if none.
4065 >         *
4066 >         * @param transformer a function returning the transformation
4067 >         * for an element, or null of there is no transformation (in
4068 >         * which case it is not combined).
4069 >         * @param reducer a commutative associative combining function
4070 >         * @return the result of accumulating the given transformation
4071 >         * of all entries
4072 >         */
4073 >        public <U> U reduceEntries(Fun<Map.Entry<K,V>, ? extends U> transformer,
4074 >                                   BiFun<? super U, ? super U, ? extends U> reducer) {
4075 >            return fjp.invoke(ForkJoinTasks.reduceEntries
4076 >                              (ConcurrentHashMapV8.this, transformer, reducer));
4077 >        }
4078 >
4079 >        /**
4080 >         * Returns the result of accumulating the given transformation
4081 >         * of all entries using the given reducer to combine values,
4082 >         * and the given basis as an identity value.
4083 >         *
4084 >         * @param transformer a function returning the transformation
4085 >         * for an element
4086 >         * @param basis the identity (initial default value) for the reduction
4087 >         * @param reducer a commutative associative combining function
4088 >         * @return the result of accumulating the given transformation
4089 >         * of all entries
4090 >         */
4091 >        public double reduceEntriesToDouble(ObjectToDouble<Map.Entry<K,V>> transformer,
4092 >                                            double basis,
4093 >                                            DoubleByDoubleToDouble reducer) {
4094 >            return fjp.invoke(ForkJoinTasks.reduceEntriesToDouble
4095 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4096 >        }
4097 >
4098 >        /**
4099 >         * Returns the result of accumulating the given transformation
4100 >         * of all entries using the given reducer to combine values,
4101 >         * and the given basis as an identity value.
4102 >         *
4103 >         * @param transformer a function returning the transformation
4104 >         * for an element
4105 >         * @param basis the identity (initial default value) for the reduction
4106 >         * @param reducer a commutative associative combining function
4107 >         * @return  the result of accumulating the given transformation
4108 >         * of all entries
4109 >         */
4110 >        public long reduceEntriesToLong(ObjectToLong<Map.Entry<K,V>> transformer,
4111 >                                        long basis,
4112 >                                        LongByLongToLong reducer) {
4113 >            return fjp.invoke(ForkJoinTasks.reduceEntriesToLong
4114 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4115 >        }
4116 >
4117 >        /**
4118 >         * Returns the result of accumulating the given transformation
4119 >         * of all entries using the given reducer to combine values,
4120 >         * and the given basis as an identity value.
4121 >         *
4122 >         * @param transformer a function returning the transformation
4123 >         * for an element
4124 >         * @param basis the identity (initial default value) for the reduction
4125 >         * @param reducer a commutative associative combining function
4126 >         * @return the result of accumulating the given transformation
4127 >         * of all entries
4128 >         */
4129 >        public int reduceEntriesToInt(ObjectToInt<Map.Entry<K,V>> transformer,
4130 >                                      int basis,
4131 >                                      IntByIntToInt reducer) {
4132 >            return fjp.invoke(ForkJoinTasks.reduceEntriesToInt
4133 >                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4134 >        }
4135 >    }
4136 >
4137 >    // ---------------------------------------------------------------------
4138 >
4139 >    /**
4140 >     * Predefined tasks for performing bulk parallel operations on
4141 >     * ConcurrentHashMaps. These tasks follow the forms and rules used
4142 >     * in class {@link Parallel}. Each method has the same name, but
4143 >     * returns a task rather than invoking it. These methods may be
4144 >     * useful in custom applications such as submitting a task without
4145 >     * waiting for completion, or combining with other tasks.
4146 >     */
4147 >    public static class ForkJoinTasks {
4148 >        private ForkJoinTasks() {}
4149 >
4150 >        /**
4151 >         * Returns a task that when invoked, performs the given
4152 >         * action for each (key, value)
4153 >         *
4154 >         * @param map the map
4155 >         * @param action the action
4156 >         * @return the task
4157 >         */
4158 >        public static <K,V> ForkJoinTask<Void> forEach
4159 >            (ConcurrentHashMapV8<K,V> map,
4160 >             BiAction<K,V> action) {
4161 >            if (action == null) throw new NullPointerException();
4162 >            return new ForEachMappingTask<K,V>(map, action);
4163 >        }
4164 >
4165 >        /**
4166 >         * Returns a task that when invoked, performs the given
4167 >         * action for each non-null transformation of each (key, value)
4168 >         *
4169 >         * @param map the map
4170 >         * @param transformer a function returning the transformation
4171 >         * for an element, or null of there is no transformation (in
4172 >         * which case the action is not applied).
4173 >         * @param action the action
4174 >         * @return the task
4175 >         */
4176 >        public static <K,V,U> ForkJoinTask<Void> forEach
4177 >            (ConcurrentHashMapV8<K,V> map,
4178 >             BiFun<? super K, ? super V, ? extends U> transformer,
4179 >             Action<U> action) {
4180 >            if (transformer == null || action == null)
4181 >                throw new NullPointerException();
4182 >            return new ForEachTransformedMappingTask<K,V,U>
4183 >                (map, transformer, action);
4184 >        }
4185 >
4186 >        /**
4187 >         * Returns a task that when invoked, returns a non-null result
4188 >         * from applying the given search function on each (key,
4189 >         * value), or null if none. Upon success, further element
4190 >         * processing is suppressed and the results of any other
4191 >         * parallel invocations of the search function are ignored.
4192 >         *
4193 >         * @param map the map
4194 >         * @param searchFunction a function returning a non-null
4195 >         * result on success, else null
4196 >         * @return the task
4197 >         */
4198 >        public static <K,V,U> ForkJoinTask<U> search
4199 >            (ConcurrentHashMapV8<K,V> map,
4200 >             BiFun<? super K, ? super V, ? extends U> searchFunction) {
4201 >            if (searchFunction == null) throw new NullPointerException();
4202 >            return new SearchMappingsTask<K,V,U>
4203 >                (map, searchFunction,
4204 >                 new AtomicReference<U>());
4205 >        }
4206 >
4207 >        /**
4208 >         * Returns a task that when invoked, returns the result of
4209 >         * accumulating the given transformation of all (key, value) pairs
4210 >         * using the given reducer to combine values, or null if none.
4211 >         *
4212 >         * @param map the map
4213 >         * @param transformer a function returning the transformation
4214 >         * for an element, or null of there is no transformation (in
4215 >         * which case it is not combined).
4216 >         * @param reducer a commutative associative combining function
4217 >         * @return the task
4218 >         */
4219 >        public static <K,V,U> ForkJoinTask<U> reduce
4220 >            (ConcurrentHashMapV8<K,V> map,
4221 >             BiFun<? super K, ? super V, ? extends U> transformer,
4222 >             BiFun<? super U, ? super U, ? extends U> reducer) {
4223 >            if (transformer == null || reducer == null)
4224 >                throw new NullPointerException();
4225 >            return new MapReduceMappingsTask<K,V,U>
4226 >                (map, transformer, reducer);
4227 >        }
4228 >
4229 >        /**
4230 >         * Returns a task that when invoked, returns the result of
4231 >         * accumulating the given transformation of all (key, value) pairs
4232 >         * using the given reducer to combine values, and the given
4233 >         * basis as an identity value.
4234 >         *
4235 >         * @param map the map
4236 >         * @param transformer a function returning the transformation
4237 >         * for an element
4238 >         * @param basis the identity (initial default value) for the reduction
4239 >         * @param reducer a commutative associative combining function
4240 >         * @return the task
4241 >         */
4242 >        public static <K,V> ForkJoinTask<Double> reduceToDouble
4243 >            (ConcurrentHashMapV8<K,V> map,
4244 >             ObjectByObjectToDouble<? super K, ? super V> transformer,
4245 >             double basis,
4246 >             DoubleByDoubleToDouble reducer) {
4247 >            if (transformer == null || reducer == null)
4248 >                throw new NullPointerException();
4249 >            return new MapReduceMappingsToDoubleTask<K,V>
4250 >                (map, transformer, basis, reducer);
4251 >        }
4252 >
4253 >        /**
4254 >         * Returns a task that when invoked, returns the result of
4255 >         * accumulating the given transformation of all (key, value) pairs
4256 >         * using the given reducer to combine values, and the given
4257 >         * basis as an identity value.
4258 >         *
4259 >         * @param map the map
4260 >         * @param transformer a function returning the transformation
4261 >         * for an element
4262 >         * @param basis the identity (initial default value) for the reduction
4263 >         * @param reducer a commutative associative combining function
4264 >         * @return the task
4265 >         */
4266 >        public static <K,V> ForkJoinTask<Long> reduceToLong
4267 >            (ConcurrentHashMapV8<K,V> map,
4268 >             ObjectByObjectToLong<? super K, ? super V> transformer,
4269 >             long basis,
4270 >             LongByLongToLong reducer) {
4271 >            if (transformer == null || reducer == null)
4272 >                throw new NullPointerException();
4273 >            return new MapReduceMappingsToLongTask<K,V>
4274 >                (map, transformer, basis, reducer);
4275 >        }
4276 >
4277 >        /**
4278 >         * Returns a task that when invoked, returns the result of
4279 >         * accumulating the given transformation of all (key, value) pairs
4280 >         * using the given reducer to combine values, and the given
4281 >         * basis as an identity value.
4282 >         *
4283 >         * @param transformer a function returning the transformation
4284 >         * for an element
4285 >         * @param basis the identity (initial default value) for the reduction
4286 >         * @param reducer a commutative associative combining function
4287 >         * @return the task
4288 >         */
4289 >        public static <K,V> ForkJoinTask<Integer> reduceToInt
4290 >            (ConcurrentHashMapV8<K,V> map,
4291 >             ObjectByObjectToInt<? super K, ? super V> transformer,
4292 >             int basis,
4293 >             IntByIntToInt reducer) {
4294 >            if (transformer == null || reducer == null)
4295 >                throw new NullPointerException();
4296 >            return new MapReduceMappingsToIntTask<K,V>
4297 >                (map, transformer, basis, reducer);
4298 >        }
4299 >
4300 >        /**
4301 >         * Returns a task that when invoked, performs the given action
4302 >         * for each key.
4303 >         *
4304 >         * @param map the map
4305 >         * @param action the action
4306 >         * @return the task
4307 >         */
4308 >        public static <K,V> ForkJoinTask<Void> forEachKey
4309 >            (ConcurrentHashMapV8<K,V> map,
4310 >             Action<K> action) {
4311 >            if (action == null) throw new NullPointerException();
4312 >            return new ForEachKeyTask<K,V>(map, action);
4313 >        }
4314 >
4315 >        /**
4316 >         * Returns a task that when invoked, performs the given action
4317 >         * for each non-null transformation of each key.
4318 >         *
4319 >         * @param map the map
4320 >         * @param transformer a function returning the transformation
4321 >         * for an element, or null of there is no transformation (in
4322 >         * which case the action is not applied).
4323 >         * @param action the action
4324 >         * @return the task
4325 >         */
4326 >        public static <K,V,U> ForkJoinTask<Void> forEachKey
4327 >            (ConcurrentHashMapV8<K,V> map,
4328 >             Fun<? super K, ? extends U> transformer,
4329 >             Action<U> action) {
4330 >            if (transformer == null || action == null)
4331 >                throw new NullPointerException();
4332 >            return new ForEachTransformedKeyTask<K,V,U>
4333 >                (map, transformer, action);
4334 >        }
4335 >
4336 >        /**
4337 >         * Returns a task that when invoked, returns a non-null result
4338 >         * from applying the given search function on each key, or
4339 >         * null if none.  Upon success, further element processing is
4340 >         * suppressed and the results of any other parallel
4341 >         * invocations of the search function are ignored.
4342 >         *
4343 >         * @param map the map
4344 >         * @param searchFunction a function returning a non-null
4345 >         * result on success, else null
4346 >         * @return the task
4347 >         */
4348 >        public static <K,V,U> ForkJoinTask<U> searchKeys
4349 >            (ConcurrentHashMapV8<K,V> map,
4350 >             Fun<? super K, ? extends U> searchFunction) {
4351 >            if (searchFunction == null) throw new NullPointerException();
4352 >            return new SearchKeysTask<K,V,U>
4353 >                (map, searchFunction,
4354 >                 new AtomicReference<U>());
4355 >        }
4356 >
4357 >        /**
4358 >         * Returns a task that when invoked, returns the result of
4359 >         * accumulating all keys using the given reducer to combine
4360 >         * values, or null if none.
4361 >         *
4362 >         * @param map the map
4363 >         * @param reducer a commutative associative combining function
4364 >         * @return the task
4365 >         */
4366 >        public static <K,V> ForkJoinTask<K> reduceKeys
4367 >            (ConcurrentHashMapV8<K,V> map,
4368 >             BiFun<? super K, ? super K, ? extends K> reducer) {
4369 >            if (reducer == null) throw new NullPointerException();
4370 >            return new ReduceKeysTask<K,V>
4371 >                (map, reducer);
4372 >        }
4373 >
4374 >        /**
4375 >         * Returns a task that when invoked, returns the result of
4376 >         * accumulating the given transformation of all keys using the given
4377 >         * reducer to combine values, or null if none.
4378 >         *
4379 >         * @param map the map
4380 >         * @param transformer a function returning the transformation
4381 >         * for an element, or null of there is no transformation (in
4382 >         * which case it is not combined).
4383 >         * @param reducer a commutative associative combining function
4384 >         * @return the task
4385 >         */
4386 >        public static <K,V,U> ForkJoinTask<U> reduceKeys
4387 >            (ConcurrentHashMapV8<K,V> map,
4388 >             Fun<? super K, ? extends U> transformer,
4389 >             BiFun<? super U, ? super U, ? extends U> reducer) {
4390 >            if (transformer == null || reducer == null)
4391 >                throw new NullPointerException();
4392 >            return new MapReduceKeysTask<K,V,U>
4393 >                (map, transformer, reducer);
4394 >        }
4395 >
4396 >        /**
4397 >         * Returns a task that when invoked, returns the result of
4398 >         * accumulating the given transformation of all keys using the given
4399 >         * reducer to combine values, and the given basis as an
4400 >         * identity value.
4401 >         *
4402 >         * @param map the map
4403 >         * @param transformer a function returning the transformation
4404 >         * for an element
4405 >         * @param basis the identity (initial default value) for the reduction
4406 >         * @param reducer a commutative associative combining function
4407 >         * @return the task
4408 >         */
4409 >        public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
4410 >            (ConcurrentHashMapV8<K,V> map,
4411 >             ObjectToDouble<? super K> transformer,
4412 >             double basis,
4413 >             DoubleByDoubleToDouble reducer) {
4414 >            if (transformer == null || reducer == null)
4415 >                throw new NullPointerException();
4416 >            return new MapReduceKeysToDoubleTask<K,V>
4417 >                (map, transformer, basis, reducer);
4418 >        }
4419 >
4420 >        /**
4421 >         * Returns a task that when invoked, returns the result of
4422 >         * accumulating the given transformation of all keys using the given
4423 >         * reducer to combine values, and the given basis as an
4424 >         * identity value.
4425 >         *
4426 >         * @param map the map
4427 >         * @param transformer a function returning the transformation
4428 >         * for an element
4429 >         * @param basis the identity (initial default value) for the reduction
4430 >         * @param reducer a commutative associative combining function
4431 >         * @return the task
4432 >         */
4433 >        public static <K,V> ForkJoinTask<Long> reduceKeysToLong
4434 >            (ConcurrentHashMapV8<K,V> map,
4435 >             ObjectToLong<? super K> transformer,
4436 >             long basis,
4437 >             LongByLongToLong reducer) {
4438 >            if (transformer == null || reducer == null)
4439 >                throw new NullPointerException();
4440 >            return new MapReduceKeysToLongTask<K,V>
4441 >                (map, transformer, basis, reducer);
4442 >        }
4443 >
4444 >        /**
4445 >         * Returns a task that when invoked, returns the result of
4446 >         * accumulating the given transformation of all keys using the given
4447 >         * reducer to combine values, and the given basis as an
4448 >         * identity value.
4449 >         *
4450 >         * @param map the map
4451 >         * @param transformer a function returning the transformation
4452 >         * for an element
4453 >         * @param basis the identity (initial default value) for the reduction
4454 >         * @param reducer a commutative associative combining function
4455 >         * @return the task
4456 >         */
4457 >        public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
4458 >            (ConcurrentHashMapV8<K,V> map,
4459 >             ObjectToInt<? super K> transformer,
4460 >             int basis,
4461 >             IntByIntToInt reducer) {
4462 >            if (transformer == null || reducer == null)
4463 >                throw new NullPointerException();
4464 >            return new MapReduceKeysToIntTask<K,V>
4465 >                (map, transformer, basis, reducer);
4466 >        }
4467 >
4468 >        /**
4469 >         * Returns a task that when invoked, performs the given action
4470 >         * for each value.
4471 >         *
4472 >         * @param map the map
4473 >         * @param action the action
4474 >         */
4475 >        public static <K,V> ForkJoinTask<Void> forEachValue
4476 >            (ConcurrentHashMapV8<K,V> map,
4477 >             Action<V> action) {
4478 >            if (action == null) throw new NullPointerException();
4479 >            return new ForEachValueTask<K,V>(map, action);
4480 >        }
4481 >
4482 >        /**
4483 >         * Returns a task that when invoked, performs the given action
4484 >         * for each non-null transformation of each value.
4485 >         *
4486 >         * @param map the map
4487 >         * @param transformer a function returning the transformation
4488 >         * for an element, or null of there is no transformation (in
4489 >         * which case the action is not applied).
4490 >         * @param action the action
4491 >         */
4492 >        public static <K,V,U> ForkJoinTask<Void> forEachValue
4493 >            (ConcurrentHashMapV8<K,V> map,
4494 >             Fun<? super V, ? extends U> transformer,
4495 >             Action<U> action) {
4496 >            if (transformer == null || action == null)
4497 >                throw new NullPointerException();
4498 >            return new ForEachTransformedValueTask<K,V,U>
4499 >                (map, transformer, action);
4500 >        }
4501 >
4502 >        /**
4503 >         * Returns a task that when invoked, returns a non-null result
4504 >         * from applying the given search function on each value, or
4505 >         * null if none.  Upon success, further element processing is
4506 >         * suppressed and the results of any other parallel
4507 >         * invocations of the search function are ignored.
4508 >         *
4509 >         * @param map the map
4510 >         * @param searchFunction a function returning a non-null
4511 >         * result on success, else null
4512 >         * @return the task
4513 >         *
4514 >         */
4515 >        public static <K,V,U> ForkJoinTask<U> searchValues
4516 >            (ConcurrentHashMapV8<K,V> map,
4517 >             Fun<? super V, ? extends U> searchFunction) {
4518 >            if (searchFunction == null) throw new NullPointerException();
4519 >            return new SearchValuesTask<K,V,U>
4520 >                (map, searchFunction,
4521 >                 new AtomicReference<U>());
4522 >        }
4523 >
4524 >        /**
4525 >         * Returns a task that when invoked, returns the result of
4526 >         * accumulating all values using the given reducer to combine
4527 >         * values, or null if none.
4528 >         *
4529 >         * @param map the map
4530 >         * @param reducer a commutative associative combining function
4531 >         * @return the task
4532 >         */
4533 >        public static <K,V> ForkJoinTask<V> reduceValues
4534 >            (ConcurrentHashMapV8<K,V> map,
4535 >             BiFun<? super V, ? super V, ? extends V> reducer) {
4536 >            if (reducer == null) throw new NullPointerException();
4537 >            return new ReduceValuesTask<K,V>
4538 >                (map, reducer);
4539 >        }
4540 >
4541 >        /**
4542 >         * Returns a task that when invoked, returns the result of
4543 >         * accumulating the given transformation of all values using the
4544 >         * given reducer to combine values, or null if none.
4545 >         *
4546 >         * @param map the map
4547 >         * @param transformer a function returning the transformation
4548 >         * for an element, or null of there is no transformation (in
4549 >         * which case it is not combined).
4550 >         * @param reducer a commutative associative combining function
4551 >         * @return the task
4552 >         */
4553 >        public static <K,V,U> ForkJoinTask<U> reduceValues
4554 >            (ConcurrentHashMapV8<K,V> map,
4555 >             Fun<? super V, ? extends U> transformer,
4556 >             BiFun<? super U, ? super U, ? extends U> reducer) {
4557 >            if (transformer == null || reducer == null)
4558 >                throw new NullPointerException();
4559 >            return new MapReduceValuesTask<K,V,U>
4560 >                (map, transformer, reducer);
4561 >        }
4562 >
4563 >        /**
4564 >         * Returns a task that when invoked, returns the result of
4565 >         * accumulating the given transformation of all values using the
4566 >         * given reducer to combine values, and the given basis as an
4567 >         * identity value.
4568 >         *
4569 >         * @param map the map
4570 >         * @param transformer a function returning the transformation
4571 >         * for an element
4572 >         * @param basis the identity (initial default value) for the reduction
4573 >         * @param reducer a commutative associative combining function
4574 >         * @return the task
4575 >         */
4576 >        public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
4577 >            (ConcurrentHashMapV8<K,V> map,
4578 >             ObjectToDouble<? super V> transformer,
4579 >             double basis,
4580 >             DoubleByDoubleToDouble reducer) {
4581 >            if (transformer == null || reducer == null)
4582 >                throw new NullPointerException();
4583 >            return new MapReduceValuesToDoubleTask<K,V>
4584 >                (map, transformer, basis, reducer);
4585 >        }
4586 >
4587 >        /**
4588 >         * Returns a task that when invoked, returns the result of
4589 >         * accumulating the given transformation of all values using the
4590 >         * given reducer to combine values, and the given basis as an
4591 >         * identity value.
4592 >         *
4593 >         * @param map the map
4594 >         * @param transformer a function returning the transformation
4595 >         * for an element
4596 >         * @param basis the identity (initial default value) for the reduction
4597 >         * @param reducer a commutative associative combining function
4598 >         * @return the task
4599 >         */
4600 >        public static <K,V> ForkJoinTask<Long> reduceValuesToLong
4601 >            (ConcurrentHashMapV8<K,V> map,
4602 >             ObjectToLong<? super V> transformer,
4603 >             long basis,
4604 >             LongByLongToLong reducer) {
4605 >            if (transformer == null || reducer == null)
4606 >                throw new NullPointerException();
4607 >            return new MapReduceValuesToLongTask<K,V>
4608 >                (map, transformer, basis, reducer);
4609 >        }
4610 >
4611 >        /**
4612 >         * Returns a task that when invoked, returns the result of
4613 >         * accumulating the given transformation of all values using the
4614 >         * given reducer to combine values, and the given basis as an
4615 >         * identity value.
4616 >         *
4617 >         * @param map the map
4618 >         * @param transformer a function returning the transformation
4619 >         * for an element
4620 >         * @param basis the identity (initial default value) for the reduction
4621 >         * @param reducer a commutative associative combining function
4622 >         * @return the task
4623 >         */
4624 >        public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
4625 >            (ConcurrentHashMapV8<K,V> map,
4626 >             ObjectToInt<? super V> transformer,
4627 >             int basis,
4628 >             IntByIntToInt reducer) {
4629 >            if (transformer == null || reducer == null)
4630 >                throw new NullPointerException();
4631 >            return new MapReduceValuesToIntTask<K,V>
4632 >                (map, transformer, basis, reducer);
4633 >        }
4634 >
4635 >        /**
4636 >         * Returns a task that when invoked, perform the given action
4637 >         * for each entry.
4638 >         *
4639 >         * @param map the map
4640 >         * @param action the action
4641 >         */
4642 >        public static <K,V> ForkJoinTask<Void> forEachEntry
4643 >            (ConcurrentHashMapV8<K,V> map,
4644 >             Action<Map.Entry<K,V>> action) {
4645 >            if (action == null) throw new NullPointerException();
4646 >            return new ForEachEntryTask<K,V>(map, action);
4647 >        }
4648 >
4649 >        /**
4650 >         * Returns a task that when invoked, perform the given action
4651 >         * for each non-null transformation of each entry.
4652 >         *
4653 >         * @param map the map
4654 >         * @param transformer a function returning the transformation
4655 >         * for an element, or null of there is no transformation (in
4656 >         * which case the action is not applied).
4657 >         * @param action the action
4658 >         */
4659 >        public static <K,V,U> ForkJoinTask<Void> forEachEntry
4660 >            (ConcurrentHashMapV8<K,V> map,
4661 >             Fun<Map.Entry<K,V>, ? extends U> transformer,
4662 >             Action<U> action) {
4663 >            if (transformer == null || action == null)
4664 >                throw new NullPointerException();
4665 >            return new ForEachTransformedEntryTask<K,V,U>
4666 >                (map, transformer, action);
4667 >        }
4668 >
4669 >        /**
4670 >         * Returns a task that when invoked, returns a non-null result
4671 >         * from applying the given search function on each entry, or
4672 >         * null if none.  Upon success, further element processing is
4673 >         * suppressed and the results of any other parallel
4674 >         * invocations of the search function are ignored.
4675 >         *
4676 >         * @param map the map
4677 >         * @param searchFunction a function returning a non-null
4678 >         * result on success, else null
4679 >         * @return the task
4680 >         *
4681 >         */
4682 >        public static <K,V,U> ForkJoinTask<U> searchEntries
4683 >            (ConcurrentHashMapV8<K,V> map,
4684 >             Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4685 >            if (searchFunction == null) throw new NullPointerException();
4686 >            return new SearchEntriesTask<K,V,U>
4687 >                (map, searchFunction,
4688 >                 new AtomicReference<U>());
4689 >        }
4690 >
4691 >        /**
4692 >         * Returns a task that when invoked, returns the result of
4693 >         * accumulating all entries using the given reducer to combine
4694 >         * values, or null if none.
4695 >         *
4696 >         * @param map the map
4697 >         * @param reducer a commutative associative combining function
4698 >         * @return the task
4699 >         */
4700 >        public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
4701 >            (ConcurrentHashMapV8<K,V> map,
4702 >             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4703 >            if (reducer == null) throw new NullPointerException();
4704 >            return new ReduceEntriesTask<K,V>
4705 >                (map, reducer);
4706 >        }
4707 >
4708 >        /**
4709 >         * Returns a task that when invoked, returns the result of
4710 >         * accumulating the given transformation of all entries using the
4711 >         * given reducer to combine values, or null if none.
4712 >         *
4713 >         * @param map the map
4714 >         * @param transformer a function returning the transformation
4715 >         * for an element, or null of there is no transformation (in
4716 >         * which case it is not combined).
4717 >         * @param reducer a commutative associative combining function
4718 >         * @return the task
4719 >         */
4720 >        public static <K,V,U> ForkJoinTask<U> reduceEntries
4721 >            (ConcurrentHashMapV8<K,V> map,
4722 >             Fun<Map.Entry<K,V>, ? extends U> transformer,
4723 >             BiFun<? super U, ? super U, ? extends U> reducer) {
4724 >            if (transformer == null || reducer == null)
4725 >                throw new NullPointerException();
4726 >            return new MapReduceEntriesTask<K,V,U>
4727 >                (map, transformer, reducer);
4728 >        }
4729 >
4730 >        /**
4731 >         * Returns a task that when invoked, returns the result of
4732 >         * accumulating the given transformation of all entries using the
4733 >         * given reducer to combine values, and the given basis as an
4734 >         * identity value.
4735 >         *
4736 >         * @param map the map
4737 >         * @param transformer a function returning the transformation
4738 >         * for an element
4739 >         * @param basis the identity (initial default value) for the reduction
4740 >         * @param reducer a commutative associative combining function
4741 >         * @return the task
4742 >         */
4743 >        public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
4744 >            (ConcurrentHashMapV8<K,V> map,
4745 >             ObjectToDouble<Map.Entry<K,V>> transformer,
4746 >             double basis,
4747 >             DoubleByDoubleToDouble reducer) {
4748 >            if (transformer == null || reducer == null)
4749 >                throw new NullPointerException();
4750 >            return new MapReduceEntriesToDoubleTask<K,V>
4751 >                (map, transformer, basis, reducer);
4752 >        }
4753 >
4754 >        /**
4755 >         * Returns a task that when invoked, returns the result of
4756 >         * accumulating the given transformation of all entries using the
4757 >         * given reducer to combine values, and the given basis as an
4758 >         * identity value.
4759 >         *
4760 >         * @param map the map
4761 >         * @param transformer a function returning the transformation
4762 >         * for an element
4763 >         * @param basis the identity (initial default value) for the reduction
4764 >         * @param reducer a commutative associative combining function
4765 >         * @return the task
4766 >         */
4767 >        public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
4768 >            (ConcurrentHashMapV8<K,V> map,
4769 >             ObjectToLong<Map.Entry<K,V>> transformer,
4770 >             long basis,
4771 >             LongByLongToLong reducer) {
4772 >            if (transformer == null || reducer == null)
4773 >                throw new NullPointerException();
4774 >            return new MapReduceEntriesToLongTask<K,V>
4775 >                (map, transformer, basis, reducer);
4776 >        }
4777 >
4778 >        /**
4779 >         * Returns a task that when invoked, returns the result of
4780 >         * accumulating the given transformation of all entries using the
4781 >         * given reducer to combine values, and the given basis as an
4782 >         * identity value.
4783 >         *
4784 >         * @param map the map
4785 >         * @param transformer a function returning the transformation
4786 >         * for an element
4787 >         * @param basis the identity (initial default value) for the reduction
4788 >         * @param reducer a commutative associative combining function
4789 >         * @return the task
4790 >         */
4791 >        public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
4792 >            (ConcurrentHashMapV8<K,V> map,
4793 >             ObjectToInt<Map.Entry<K,V>> transformer,
4794 >             int basis,
4795 >             IntByIntToInt reducer) {
4796 >            if (transformer == null || reducer == null)
4797 >                throw new NullPointerException();
4798 >            return new MapReduceEntriesToIntTask<K,V>
4799 >                (map, transformer, basis, reducer);
4800 >        }
4801 >    }
4802 >
4803 >    // -------------------------------------------------------
4804 >
4805 >    /**
4806 >     * Base for FJ tasks for bulk operations. This adds a variant of
4807 >     * CountedCompleters and some split and merge bookkeeping to
4808 >     * iterator functionality. The forEach and reduce methods are
4809 >     * similar to those illustrated in CountedCompleter documentation,
4810 >     * except that bottom-up reduction completions perform them within
4811 >     * their compute methods. The search methods are like forEach
4812 >     * except they continually poll for success and exit early.  Also,
4813 >     * exceptions are handled in a simpler manner, by just trying to
4814 >     * complete root task exceptionally.
4815 >     */
4816 >    @SuppressWarnings("serial") static abstract class BulkTask<K,V,R> extends Traverser<K,V,R> {
4817 >        final BulkTask<K,V,?> parent;  // completion target
4818 >        int batch;                     // split control
4819 >        int pending;                   // completion control
4820 >
4821 >        /** Constructor for root tasks */
4822 >        BulkTask(ConcurrentHashMapV8<K,V> map) {
4823 >            super(map);
4824 >            this.parent = null;
4825 >            this.batch = -1; // force call to batch() on execution
4826 >        }
4827 >
4828 >        /** Constructor for subtasks */
4829 >        BulkTask(BulkTask<K,V,?> parent, int batch) {
4830 >            super(parent);
4831 >            this.parent = parent;
4832 >            this.batch = batch;
4833 >        }
4834 >
4835 >        // FJ methods
4836 >
4837 >        /**
4838 >         * Propagates completion. Note that all reduce actions
4839 >         * bypass this method to combine while completing.
4840 >         */
4841 >        final void tryComplete() {
4842 >            BulkTask<K,V,?> a = this, s = a;
4843 >            for (int c;;) {
4844 >                if ((c = a.pending) == 0) {
4845 >                    if ((a = (s = a).parent) == null) {
4846 >                        s.quietlyComplete();
4847 >                        break;
4848 >                    }
4849 >                }
4850 >                else if (U.compareAndSwapInt(a, PENDING, c, c - 1))
4851 >                    break;
4852 >            }
4853 >        }
4854 >
4855 >        /**
4856 >         * Forces root task to complete.
4857 >         * @param ex if null, complete normally, else exceptionally
4858 >         * @return false to simplify use
4859 >         */
4860 >        final boolean tryCompleteComputation(Throwable ex) {
4861 >            for (BulkTask<K,V,?> a = this;;) {
4862 >                BulkTask<K,V,?> p = a.parent;
4863 >                if (p == null) {
4864 >                    if (ex != null)
4865 >                        a.completeExceptionally(ex);
4866 >                    else
4867 >                        a.quietlyComplete();
4868 >                    return false;
4869 >                }
4870 >                a = p;
4871 >            }
4872 >        }
4873 >
4874 >        /**
4875 >         * Version of tryCompleteComputation for function screening checks
4876 >         */
4877 >        final boolean abortOnNullFunction() {
4878 >            return tryCompleteComputation(new Error("Unexpected null function"));
4879 >        }
4880 >
4881 >        // utilities
4882 >
4883 >        /** CompareAndSet pending count */
4884 >        final boolean casPending(int cmp, int val) {
4885 >            return U.compareAndSwapInt(this, PENDING, cmp, val);
4886 >        }
4887 >
4888 >        /**
4889 >         * Returns approx exp2 of the number of times (minus one) to
4890 >         * split task by two before executing leaf action. This value
4891 >         * is faster to compute and more convenient to use as a guide
4892 >         * to splitting than is the depth, since it is used while
4893 >         * dividing by two anyway.
4894 >         */
4895 >        final int batch() {
4896 >            int b = batch;
4897 >            if (b < 0) {
4898 >                long n = map.counter.sum();
4899 >                int sp = getPool().getParallelism() << 3; // slack of 8
4900 >                b = batch = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
4901 >            }
4902 >            return b;
4903 >        }
4904 >
4905 >        /**
4906 >         * Returns exportable snapshot entry.
4907 >         */
4908 >        static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
4909 >            return new AbstractMap.SimpleEntry<K,V>(k, v);
4910 >        }
4911 >
4912 >        // Unsafe mechanics
4913 >        private static final sun.misc.Unsafe U;
4914 >        private static final long PENDING;
4915 >        static {
4916 >            try {
4917 >                U = getUnsafe();
4918 >                PENDING = U.objectFieldOffset
4919 >                    (BulkTask.class.getDeclaredField("pending"));
4920 >            } catch (Exception e) {
4921 >                throw new Error(e);
4922 >            }
4923 >        }
4924 >    }
4925 >
4926 >    /*
4927 >     * Task classes. Coded in a regular but ugly format/style to
4928 >     * simplify checks that each variant differs in the right way from
4929 >     * others.
4930 >     */
4931 >
4932 >    @SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
4933 >        extends BulkTask<K,V,Void> {
4934 >        final Action<K> action;
4935 >        ForEachKeyTask
4936 >            (ConcurrentHashMapV8<K,V> m,
4937 >             Action<K> action) {
4938 >            super(m);
4939 >            this.action = action;
4940 >        }
4941 >        ForEachKeyTask
4942 >            (BulkTask<K,V,?> p, int b,
4943 >             Action<K> action) {
4944 >            super(p, b);
4945 >            this.action = action;
4946 >        }
4947 >        @SuppressWarnings("unchecked") public final boolean exec() {
4948 >            final Action<K> action = this.action;
4949 >            if (action == null)
4950 >                return abortOnNullFunction();
4951 >            try {
4952 >                int b = batch(), c;
4953 >                while (b > 1 && baseIndex != baseLimit) {
4954 >                    do {} while (!casPending(c = pending, c+1));
4955 >                    new ForEachKeyTask<K,V>(this, b >>>= 1, action).fork();
4956 >                }
4957 >                while (advance() != null)
4958 >                    action.apply((K)nextKey);
4959 >                tryComplete();
4960 >            } catch (Throwable ex) {
4961 >                return tryCompleteComputation(ex);
4962 >            }
4963 >            return false;
4964 >        }
4965 >    }
4966 >
4967 >    @SuppressWarnings("serial") static final class ForEachValueTask<K,V>
4968 >        extends BulkTask<K,V,Void> {
4969 >        final Action<V> action;
4970 >        ForEachValueTask
4971 >            (ConcurrentHashMapV8<K,V> m,
4972 >             Action<V> action) {
4973 >            super(m);
4974 >            this.action = action;
4975 >        }
4976 >        ForEachValueTask
4977 >            (BulkTask<K,V,?> p, int b,
4978 >             Action<V> action) {
4979 >            super(p, b);
4980 >            this.action = action;
4981 >        }
4982 >        @SuppressWarnings("unchecked") public final boolean exec() {
4983 >            final Action<V> action = this.action;
4984 >            if (action == null)
4985 >                return abortOnNullFunction();
4986 >            try {
4987 >                int b = batch(), c;
4988 >                while (b > 1 && baseIndex != baseLimit) {
4989 >                    do {} while (!casPending(c = pending, c+1));
4990 >                    new ForEachValueTask<K,V>(this, b >>>= 1, action).fork();
4991 >                }
4992 >                Object v;
4993 >                while ((v = advance()) != null)
4994 >                    action.apply((V)v);
4995 >                tryComplete();
4996 >            } catch (Throwable ex) {
4997 >                return tryCompleteComputation(ex);
4998 >            }
4999 >            return false;
5000 >        }
5001 >    }
5002 >
5003 >    @SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5004 >        extends BulkTask<K,V,Void> {
5005 >        final Action<Entry<K,V>> action;
5006 >        ForEachEntryTask
5007 >            (ConcurrentHashMapV8<K,V> m,
5008 >             Action<Entry<K,V>> action) {
5009 >            super(m);
5010 >            this.action = action;
5011 >        }
5012 >        ForEachEntryTask
5013 >            (BulkTask<K,V,?> p, int b,
5014 >             Action<Entry<K,V>> action) {
5015 >            super(p, b);
5016 >            this.action = action;
5017 >        }
5018 >        @SuppressWarnings("unchecked") public final boolean exec() {
5019 >            final Action<Entry<K,V>> action = this.action;
5020 >            if (action == null)
5021 >                return abortOnNullFunction();
5022 >            try {
5023 >                int b = batch(), c;
5024 >                while (b > 1 && baseIndex != baseLimit) {
5025 >                    do {} while (!casPending(c = pending, c+1));
5026 >                    new ForEachEntryTask<K,V>(this, b >>>= 1, action).fork();
5027 >                }
5028 >                Object v;
5029 >                while ((v = advance()) != null)
5030 >                    action.apply(entryFor((K)nextKey, (V)v));
5031 >                tryComplete();
5032 >            } catch (Throwable ex) {
5033 >                return tryCompleteComputation(ex);
5034 >            }
5035 >            return false;
5036          }
5037      }
5038  
5039 +    @SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5040 +        extends BulkTask<K,V,Void> {
5041 +        final BiAction<K,V> action;
5042 +        ForEachMappingTask
5043 +            (ConcurrentHashMapV8<K,V> m,
5044 +             BiAction<K,V> action) {
5045 +            super(m);
5046 +            this.action = action;
5047 +        }
5048 +        ForEachMappingTask
5049 +            (BulkTask<K,V,?> p, int b,
5050 +             BiAction<K,V> action) {
5051 +            super(p, b);
5052 +            this.action = action;
5053 +        }
5054 +
5055 +        @SuppressWarnings("unchecked") public final boolean exec() {
5056 +            final BiAction<K,V> action = this.action;
5057 +            if (action == null)
5058 +                return abortOnNullFunction();
5059 +            try {
5060 +                int b = batch(), c;
5061 +                while (b > 1 && baseIndex != baseLimit) {
5062 +                    do {} while (!casPending(c = pending, c+1));
5063 +                    new ForEachMappingTask<K,V>(this, b >>>= 1,
5064 +                                                action).fork();
5065 +                }
5066 +                Object v;
5067 +                while ((v = advance()) != null)
5068 +                    action.apply((K)nextKey, (V)v);
5069 +                tryComplete();
5070 +            } catch (Throwable ex) {
5071 +                return tryCompleteComputation(ex);
5072 +            }
5073 +            return false;
5074 +        }
5075 +    }
5076 +
5077 +    @SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5078 +        extends BulkTask<K,V,Void> {
5079 +        final Fun<? super K, ? extends U> transformer;
5080 +        final Action<U> action;
5081 +        ForEachTransformedKeyTask
5082 +            (ConcurrentHashMapV8<K,V> m,
5083 +             Fun<? super K, ? extends U> transformer,
5084 +             Action<U> action) {
5085 +            super(m);
5086 +            this.transformer = transformer;
5087 +            this.action = action;
5088 +
5089 +        }
5090 +        ForEachTransformedKeyTask
5091 +            (BulkTask<K,V,?> p, int b,
5092 +             Fun<? super K, ? extends U> transformer,
5093 +             Action<U> action) {
5094 +            super(p, b);
5095 +            this.transformer = transformer;
5096 +            this.action = action;
5097 +        }
5098 +        @SuppressWarnings("unchecked") public final boolean exec() {
5099 +            final Fun<? super K, ? extends U> transformer =
5100 +                this.transformer;
5101 +            final Action<U> action = this.action;
5102 +            if (transformer == null || action == null)
5103 +                return abortOnNullFunction();
5104 +            try {
5105 +                int b = batch(), c;
5106 +                while (b > 1 && baseIndex != baseLimit) {
5107 +                    do {} while (!casPending(c = pending, c+1));
5108 +                    new ForEachTransformedKeyTask<K,V,U>
5109 +                        (this, b >>>= 1, transformer, action).fork();
5110 +                }
5111 +                U u;
5112 +                while (advance() != null) {
5113 +                    if ((u = transformer.apply((K)nextKey)) != null)
5114 +                        action.apply(u);
5115 +                }
5116 +                tryComplete();
5117 +            } catch (Throwable ex) {
5118 +                return tryCompleteComputation(ex);
5119 +            }
5120 +            return false;
5121 +        }
5122 +    }
5123 +
5124 +    @SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5125 +        extends BulkTask<K,V,Void> {
5126 +        final Fun<? super V, ? extends U> transformer;
5127 +        final Action<U> action;
5128 +        ForEachTransformedValueTask
5129 +            (ConcurrentHashMapV8<K,V> m,
5130 +             Fun<? super V, ? extends U> transformer,
5131 +             Action<U> action) {
5132 +            super(m);
5133 +            this.transformer = transformer;
5134 +            this.action = action;
5135 +
5136 +        }
5137 +        ForEachTransformedValueTask
5138 +            (BulkTask<K,V,?> p, int b,
5139 +             Fun<? super V, ? extends U> transformer,
5140 +             Action<U> action) {
5141 +            super(p, b);
5142 +            this.transformer = transformer;
5143 +            this.action = action;
5144 +        }
5145 +        @SuppressWarnings("unchecked") public final boolean exec() {
5146 +            final Fun<? super V, ? extends U> transformer =
5147 +                this.transformer;
5148 +            final Action<U> action = this.action;
5149 +            if (transformer == null || action == null)
5150 +                return abortOnNullFunction();
5151 +            try {
5152 +                int b = batch(), c;
5153 +                while (b > 1 && baseIndex != baseLimit) {
5154 +                    do {} while (!casPending(c = pending, c+1));
5155 +                    new ForEachTransformedValueTask<K,V,U>
5156 +                        (this, b >>>= 1, transformer, action).fork();
5157 +                }
5158 +                Object v; U u;
5159 +                while ((v = advance()) != null) {
5160 +                    if ((u = transformer.apply((V)v)) != null)
5161 +                        action.apply(u);
5162 +                }
5163 +                tryComplete();
5164 +            } catch (Throwable ex) {
5165 +                return tryCompleteComputation(ex);
5166 +            }
5167 +            return false;
5168 +        }
5169 +    }
5170 +
5171 +    @SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5172 +        extends BulkTask<K,V,Void> {
5173 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5174 +        final Action<U> action;
5175 +        ForEachTransformedEntryTask
5176 +            (ConcurrentHashMapV8<K,V> m,
5177 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5178 +             Action<U> action) {
5179 +            super(m);
5180 +            this.transformer = transformer;
5181 +            this.action = action;
5182 +
5183 +        }
5184 +        ForEachTransformedEntryTask
5185 +            (BulkTask<K,V,?> p, int b,
5186 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5187 +             Action<U> action) {
5188 +            super(p, b);
5189 +            this.transformer = transformer;
5190 +            this.action = action;
5191 +        }
5192 +        @SuppressWarnings("unchecked") public final boolean exec() {
5193 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5194 +                this.transformer;
5195 +            final Action<U> action = this.action;
5196 +            if (transformer == null || action == null)
5197 +                return abortOnNullFunction();
5198 +            try {
5199 +                int b = batch(), c;
5200 +                while (b > 1 && baseIndex != baseLimit) {
5201 +                    do {} while (!casPending(c = pending, c+1));
5202 +                    new ForEachTransformedEntryTask<K,V,U>
5203 +                        (this, b >>>= 1, transformer, action).fork();
5204 +                }
5205 +                Object v; U u;
5206 +                while ((v = advance()) != null) {
5207 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5208 +                        action.apply(u);
5209 +                }
5210 +                tryComplete();
5211 +            } catch (Throwable ex) {
5212 +                return tryCompleteComputation(ex);
5213 +            }
5214 +            return false;
5215 +        }
5216 +    }
5217 +
5218 +    @SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5219 +        extends BulkTask<K,V,Void> {
5220 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5221 +        final Action<U> action;
5222 +        ForEachTransformedMappingTask
5223 +            (ConcurrentHashMapV8<K,V> m,
5224 +             BiFun<? super K, ? super V, ? extends U> transformer,
5225 +             Action<U> action) {
5226 +            super(m);
5227 +            this.transformer = transformer;
5228 +            this.action = action;
5229 +
5230 +        }
5231 +        ForEachTransformedMappingTask
5232 +            (BulkTask<K,V,?> p, int b,
5233 +             BiFun<? super K, ? super V, ? extends U> transformer,
5234 +             Action<U> action) {
5235 +            super(p, b);
5236 +            this.transformer = transformer;
5237 +            this.action = action;
5238 +        }
5239 +        @SuppressWarnings("unchecked") public final boolean exec() {
5240 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5241 +                this.transformer;
5242 +            final Action<U> action = this.action;
5243 +            if (transformer == null || action == null)
5244 +                return abortOnNullFunction();
5245 +            try {
5246 +                int b = batch(), c;
5247 +                while (b > 1 && baseIndex != baseLimit) {
5248 +                    do {} while (!casPending(c = pending, c+1));
5249 +                    new ForEachTransformedMappingTask<K,V,U>
5250 +                        (this, b >>>= 1, transformer, action).fork();
5251 +                }
5252 +                Object v; U u;
5253 +                while ((v = advance()) != null) {
5254 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5255 +                        action.apply(u);
5256 +                }
5257 +                tryComplete();
5258 +            } catch (Throwable ex) {
5259 +                return tryCompleteComputation(ex);
5260 +            }
5261 +            return false;
5262 +        }
5263 +    }
5264 +
5265 +    @SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5266 +        extends BulkTask<K,V,U> {
5267 +        final Fun<? super K, ? extends U> searchFunction;
5268 +        final AtomicReference<U> result;
5269 +        SearchKeysTask
5270 +            (ConcurrentHashMapV8<K,V> m,
5271 +             Fun<? super K, ? extends U> searchFunction,
5272 +             AtomicReference<U> result) {
5273 +            super(m);
5274 +            this.searchFunction = searchFunction; this.result = result;
5275 +        }
5276 +        SearchKeysTask
5277 +            (BulkTask<K,V,?> p, int b,
5278 +             Fun<? super K, ? extends U> searchFunction,
5279 +             AtomicReference<U> result) {
5280 +            super(p, b);
5281 +            this.searchFunction = searchFunction; this.result = result;
5282 +        }
5283 +        @SuppressWarnings("unchecked") public final boolean exec() {
5284 +            AtomicReference<U> result = this.result;
5285 +            final Fun<? super K, ? extends U> searchFunction =
5286 +                this.searchFunction;
5287 +            if (searchFunction == null || result == null)
5288 +                return abortOnNullFunction();
5289 +            try {
5290 +                int b = batch(), c;
5291 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5292 +                    do {} while (!casPending(c = pending, c+1));
5293 +                    new SearchKeysTask<K,V,U>(this, b >>>= 1,
5294 +                                              searchFunction, result).fork();
5295 +                }
5296 +                U u;
5297 +                while (result.get() == null && advance() != null) {
5298 +                    if ((u = searchFunction.apply((K)nextKey)) != null) {
5299 +                        if (result.compareAndSet(null, u))
5300 +                            tryCompleteComputation(null);
5301 +                        break;
5302 +                    }
5303 +                }
5304 +                tryComplete();
5305 +            } catch (Throwable ex) {
5306 +                return tryCompleteComputation(ex);
5307 +            }
5308 +            return false;
5309 +        }
5310 +        public final U getRawResult() { return result.get(); }
5311 +    }
5312 +
5313 +    @SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5314 +        extends BulkTask<K,V,U> {
5315 +        final Fun<? super V, ? extends U> searchFunction;
5316 +        final AtomicReference<U> result;
5317 +        SearchValuesTask
5318 +            (ConcurrentHashMapV8<K,V> m,
5319 +             Fun<? super V, ? extends U> searchFunction,
5320 +             AtomicReference<U> result) {
5321 +            super(m);
5322 +            this.searchFunction = searchFunction; this.result = result;
5323 +        }
5324 +        SearchValuesTask
5325 +            (BulkTask<K,V,?> p, int b,
5326 +             Fun<? super V, ? extends U> searchFunction,
5327 +             AtomicReference<U> result) {
5328 +            super(p, b);
5329 +            this.searchFunction = searchFunction; this.result = result;
5330 +        }
5331 +        @SuppressWarnings("unchecked") public final boolean exec() {
5332 +            AtomicReference<U> result = this.result;
5333 +            final Fun<? super V, ? extends U> searchFunction =
5334 +                this.searchFunction;
5335 +            if (searchFunction == null || result == null)
5336 +                return abortOnNullFunction();
5337 +            try {
5338 +                int b = batch(), c;
5339 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5340 +                    do {} while (!casPending(c = pending, c+1));
5341 +                    new SearchValuesTask<K,V,U>(this, b >>>= 1,
5342 +                                                searchFunction, result).fork();
5343 +                }
5344 +                Object v; U u;
5345 +                while (result.get() == null && (v = advance()) != null) {
5346 +                    if ((u = searchFunction.apply((V)v)) != null) {
5347 +                        if (result.compareAndSet(null, u))
5348 +                            tryCompleteComputation(null);
5349 +                        break;
5350 +                    }
5351 +                }
5352 +                tryComplete();
5353 +            } catch (Throwable ex) {
5354 +                return tryCompleteComputation(ex);
5355 +            }
5356 +            return false;
5357 +        }
5358 +        public final U getRawResult() { return result.get(); }
5359 +    }
5360 +
5361 +    @SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5362 +        extends BulkTask<K,V,U> {
5363 +        final Fun<Entry<K,V>, ? extends U> searchFunction;
5364 +        final AtomicReference<U> result;
5365 +        SearchEntriesTask
5366 +            (ConcurrentHashMapV8<K,V> m,
5367 +             Fun<Entry<K,V>, ? extends U> searchFunction,
5368 +             AtomicReference<U> result) {
5369 +            super(m);
5370 +            this.searchFunction = searchFunction; this.result = result;
5371 +        }
5372 +        SearchEntriesTask
5373 +            (BulkTask<K,V,?> p, int b,
5374 +             Fun<Entry<K,V>, ? extends U> searchFunction,
5375 +             AtomicReference<U> result) {
5376 +            super(p, b);
5377 +            this.searchFunction = searchFunction; this.result = result;
5378 +        }
5379 +        @SuppressWarnings("unchecked") public final boolean exec() {
5380 +            AtomicReference<U> result = this.result;
5381 +            final Fun<Entry<K,V>, ? extends U> searchFunction =
5382 +                this.searchFunction;
5383 +            if (searchFunction == null || result == null)
5384 +                return abortOnNullFunction();
5385 +            try {
5386 +                int b = batch(), c;
5387 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5388 +                    do {} while (!casPending(c = pending, c+1));
5389 +                    new SearchEntriesTask<K,V,U>(this, b >>>= 1,
5390 +                                                 searchFunction, result).fork();
5391 +                }
5392 +                Object v; U u;
5393 +                while (result.get() == null && (v = advance()) != null) {
5394 +                    if ((u = searchFunction.apply(entryFor((K)nextKey, (V)v))) != null) {
5395 +                        if (result.compareAndSet(null, u))
5396 +                            tryCompleteComputation(null);
5397 +                        break;
5398 +                    }
5399 +                }
5400 +                tryComplete();
5401 +            } catch (Throwable ex) {
5402 +                return tryCompleteComputation(ex);
5403 +            }
5404 +            return false;
5405 +        }
5406 +        public final U getRawResult() { return result.get(); }
5407 +    }
5408 +
5409 +    @SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5410 +        extends BulkTask<K,V,U> {
5411 +        final BiFun<? super K, ? super V, ? extends U> searchFunction;
5412 +        final AtomicReference<U> result;
5413 +        SearchMappingsTask
5414 +            (ConcurrentHashMapV8<K,V> m,
5415 +             BiFun<? super K, ? super V, ? extends U> searchFunction,
5416 +             AtomicReference<U> result) {
5417 +            super(m);
5418 +            this.searchFunction = searchFunction; this.result = result;
5419 +        }
5420 +        SearchMappingsTask
5421 +            (BulkTask<K,V,?> p, int b,
5422 +             BiFun<? super K, ? super V, ? extends U> searchFunction,
5423 +             AtomicReference<U> result) {
5424 +            super(p, b);
5425 +            this.searchFunction = searchFunction; this.result = result;
5426 +        }
5427 +        @SuppressWarnings("unchecked") public final boolean exec() {
5428 +            AtomicReference<U> result = this.result;
5429 +            final BiFun<? super K, ? super V, ? extends U> searchFunction =
5430 +                this.searchFunction;
5431 +            if (searchFunction == null || result == null)
5432 +                return abortOnNullFunction();
5433 +            try {
5434 +                int b = batch(), c;
5435 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5436 +                    do {} while (!casPending(c = pending, c+1));
5437 +                    new SearchMappingsTask<K,V,U>(this, b >>>= 1,
5438 +                                                  searchFunction, result).fork();
5439 +                }
5440 +                Object v; U u;
5441 +                while (result.get() == null && (v = advance()) != null) {
5442 +                    if ((u = searchFunction.apply((K)nextKey, (V)v)) != null) {
5443 +                        if (result.compareAndSet(null, u))
5444 +                            tryCompleteComputation(null);
5445 +                        break;
5446 +                    }
5447 +                }
5448 +                tryComplete();
5449 +            } catch (Throwable ex) {
5450 +                return tryCompleteComputation(ex);
5451 +            }
5452 +            return false;
5453 +        }
5454 +        public final U getRawResult() { return result.get(); }
5455 +    }
5456 +
5457 +    @SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5458 +        extends BulkTask<K,V,K> {
5459 +        final BiFun<? super K, ? super K, ? extends K> reducer;
5460 +        K result;
5461 +        ReduceKeysTask<K,V> rights, nextRight;
5462 +        ReduceKeysTask
5463 +            (ConcurrentHashMapV8<K,V> m,
5464 +             BiFun<? super K, ? super K, ? extends K> reducer) {
5465 +            super(m);
5466 +            this.reducer = reducer;
5467 +        }
5468 +        ReduceKeysTask
5469 +            (BulkTask<K,V,?> p, int b,
5470 +             ReduceKeysTask<K,V> nextRight,
5471 +             BiFun<? super K, ? super K, ? extends K> reducer) {
5472 +            super(p, b); this.nextRight = nextRight;
5473 +            this.reducer = reducer;
5474 +        }
5475 +
5476 +        @SuppressWarnings("unchecked") public final boolean exec() {
5477 +            final BiFun<? super K, ? super K, ? extends K> reducer =
5478 +                this.reducer;
5479 +            if (reducer == null)
5480 +                return abortOnNullFunction();
5481 +            try {
5482 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5483 +                    do {} while (!casPending(c = pending, c+1));
5484 +                    (rights = new ReduceKeysTask<K,V>
5485 +                     (this, b >>>= 1, rights, reducer)).fork();
5486 +                }
5487 +                K r = null;
5488 +                while (advance() != null) {
5489 +                    K u = (K)nextKey;
5490 +                    r = (r == null) ? u : reducer.apply(r, u);
5491 +                }
5492 +                result = r;
5493 +                for (ReduceKeysTask<K,V> t = this, s;;) {
5494 +                    int c; BulkTask<K,V,?> par; K tr, sr;
5495 +                    if ((c = t.pending) == 0) {
5496 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5497 +                            if ((sr = s.result) != null)
5498 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5499 +                        }
5500 +                        if ((par = t.parent) == null ||
5501 +                            !(par instanceof ReduceKeysTask)) {
5502 +                            t.quietlyComplete();
5503 +                            break;
5504 +                        }
5505 +                        t = (ReduceKeysTask<K,V>)par;
5506 +                    }
5507 +                    else if (t.casPending(c, c - 1))
5508 +                        break;
5509 +                }
5510 +            } catch (Throwable ex) {
5511 +                return tryCompleteComputation(ex);
5512 +            }
5513 +            return false;
5514 +        }
5515 +        public final K getRawResult() { return result; }
5516 +    }
5517 +
5518 +    @SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5519 +        extends BulkTask<K,V,V> {
5520 +        final BiFun<? super V, ? super V, ? extends V> reducer;
5521 +        V result;
5522 +        ReduceValuesTask<K,V> rights, nextRight;
5523 +        ReduceValuesTask
5524 +            (ConcurrentHashMapV8<K,V> m,
5525 +             BiFun<? super V, ? super V, ? extends V> reducer) {
5526 +            super(m);
5527 +            this.reducer = reducer;
5528 +        }
5529 +        ReduceValuesTask
5530 +            (BulkTask<K,V,?> p, int b,
5531 +             ReduceValuesTask<K,V> nextRight,
5532 +             BiFun<? super V, ? super V, ? extends V> reducer) {
5533 +            super(p, b); this.nextRight = nextRight;
5534 +            this.reducer = reducer;
5535 +        }
5536 +
5537 +        @SuppressWarnings("unchecked") public final boolean exec() {
5538 +            final BiFun<? super V, ? super V, ? extends V> reducer =
5539 +                this.reducer;
5540 +            if (reducer == null)
5541 +                return abortOnNullFunction();
5542 +            try {
5543 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5544 +                    do {} while (!casPending(c = pending, c+1));
5545 +                    (rights = new ReduceValuesTask<K,V>
5546 +                     (this, b >>>= 1, rights, reducer)).fork();
5547 +                }
5548 +                V r = null;
5549 +                Object v;
5550 +                while ((v = advance()) != null) {
5551 +                    V u = (V)v;
5552 +                    r = (r == null) ? u : reducer.apply(r, u);
5553 +                }
5554 +                result = r;
5555 +                for (ReduceValuesTask<K,V> t = this, s;;) {
5556 +                    int c; BulkTask<K,V,?> par; V tr, sr;
5557 +                    if ((c = t.pending) == 0) {
5558 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5559 +                            if ((sr = s.result) != null)
5560 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5561 +                        }
5562 +                        if ((par = t.parent) == null ||
5563 +                            !(par instanceof ReduceValuesTask)) {
5564 +                            t.quietlyComplete();
5565 +                            break;
5566 +                        }
5567 +                        t = (ReduceValuesTask<K,V>)par;
5568 +                    }
5569 +                    else if (t.casPending(c, c - 1))
5570 +                        break;
5571 +                }
5572 +            } catch (Throwable ex) {
5573 +                return tryCompleteComputation(ex);
5574 +            }
5575 +            return false;
5576 +        }
5577 +        public final V getRawResult() { return result; }
5578 +    }
5579 +
5580 +    @SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
5581 +        extends BulkTask<K,V,Map.Entry<K,V>> {
5582 +        final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5583 +        Map.Entry<K,V> result;
5584 +        ReduceEntriesTask<K,V> rights, nextRight;
5585 +        ReduceEntriesTask
5586 +            (ConcurrentHashMapV8<K,V> m,
5587 +             BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5588 +            super(m);
5589 +            this.reducer = reducer;
5590 +        }
5591 +        ReduceEntriesTask
5592 +            (BulkTask<K,V,?> p, int b,
5593 +             ReduceEntriesTask<K,V> nextRight,
5594 +             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5595 +            super(p, b); this.nextRight = nextRight;
5596 +            this.reducer = reducer;
5597 +        }
5598 +
5599 +        @SuppressWarnings("unchecked") public final boolean exec() {
5600 +            final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer =
5601 +                this.reducer;
5602 +            if (reducer == null)
5603 +                return abortOnNullFunction();
5604 +            try {
5605 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5606 +                    do {} while (!casPending(c = pending, c+1));
5607 +                    (rights = new ReduceEntriesTask<K,V>
5608 +                     (this, b >>>= 1, rights, reducer)).fork();
5609 +                }
5610 +                Map.Entry<K,V> r = null;
5611 +                Object v;
5612 +                while ((v = advance()) != null) {
5613 +                    Map.Entry<K,V> u = entryFor((K)nextKey, (V)v);
5614 +                    r = (r == null) ? u : reducer.apply(r, u);
5615 +                }
5616 +                result = r;
5617 +                for (ReduceEntriesTask<K,V> t = this, s;;) {
5618 +                    int c; BulkTask<K,V,?> par; Map.Entry<K,V> tr, sr;
5619 +                    if ((c = t.pending) == 0) {
5620 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5621 +                            if ((sr = s.result) != null)
5622 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5623 +                        }
5624 +                        if ((par = t.parent) == null ||
5625 +                            !(par instanceof ReduceEntriesTask)) {
5626 +                            t.quietlyComplete();
5627 +                            break;
5628 +                        }
5629 +                        t = (ReduceEntriesTask<K,V>)par;
5630 +                    }
5631 +                    else if (t.casPending(c, c - 1))
5632 +                        break;
5633 +                }
5634 +            } catch (Throwable ex) {
5635 +                return tryCompleteComputation(ex);
5636 +            }
5637 +            return false;
5638 +        }
5639 +        public final Map.Entry<K,V> getRawResult() { return result; }
5640 +    }
5641 +
5642 +    @SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
5643 +        extends BulkTask<K,V,U> {
5644 +        final Fun<? super K, ? extends U> transformer;
5645 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5646 +        U result;
5647 +        MapReduceKeysTask<K,V,U> rights, nextRight;
5648 +        MapReduceKeysTask
5649 +            (ConcurrentHashMapV8<K,V> m,
5650 +             Fun<? super K, ? extends U> transformer,
5651 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5652 +            super(m);
5653 +            this.transformer = transformer;
5654 +            this.reducer = reducer;
5655 +        }
5656 +        MapReduceKeysTask
5657 +            (BulkTask<K,V,?> p, int b,
5658 +             MapReduceKeysTask<K,V,U> nextRight,
5659 +             Fun<? super K, ? extends U> transformer,
5660 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5661 +            super(p, b); this.nextRight = nextRight;
5662 +            this.transformer = transformer;
5663 +            this.reducer = reducer;
5664 +        }
5665 +        @SuppressWarnings("unchecked") public final boolean exec() {
5666 +            final Fun<? super K, ? extends U> transformer =
5667 +                this.transformer;
5668 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5669 +                this.reducer;
5670 +            if (transformer == null || reducer == null)
5671 +                return abortOnNullFunction();
5672 +            try {
5673 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5674 +                    do {} while (!casPending(c = pending, c+1));
5675 +                    (rights = new MapReduceKeysTask<K,V,U>
5676 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5677 +                }
5678 +                U r = null, u;
5679 +                while (advance() != null) {
5680 +                    if ((u = transformer.apply((K)nextKey)) != null)
5681 +                        r = (r == null) ? u : reducer.apply(r, u);
5682 +                }
5683 +                result = r;
5684 +                for (MapReduceKeysTask<K,V,U> t = this, s;;) {
5685 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5686 +                    if ((c = t.pending) == 0) {
5687 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5688 +                            if ((sr = s.result) != null)
5689 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5690 +                        }
5691 +                        if ((par = t.parent) == null ||
5692 +                            !(par instanceof MapReduceKeysTask)) {
5693 +                            t.quietlyComplete();
5694 +                            break;
5695 +                        }
5696 +                        t = (MapReduceKeysTask<K,V,U>)par;
5697 +                    }
5698 +                    else if (t.casPending(c, c - 1))
5699 +                        break;
5700 +                }
5701 +            } catch (Throwable ex) {
5702 +                return tryCompleteComputation(ex);
5703 +            }
5704 +            return false;
5705 +        }
5706 +        public final U getRawResult() { return result; }
5707 +    }
5708 +
5709 +    @SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
5710 +        extends BulkTask<K,V,U> {
5711 +        final Fun<? super V, ? extends U> transformer;
5712 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5713 +        U result;
5714 +        MapReduceValuesTask<K,V,U> rights, nextRight;
5715 +        MapReduceValuesTask
5716 +            (ConcurrentHashMapV8<K,V> m,
5717 +             Fun<? super V, ? extends U> transformer,
5718 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5719 +            super(m);
5720 +            this.transformer = transformer;
5721 +            this.reducer = reducer;
5722 +        }
5723 +        MapReduceValuesTask
5724 +            (BulkTask<K,V,?> p, int b,
5725 +             MapReduceValuesTask<K,V,U> nextRight,
5726 +             Fun<? super V, ? extends U> transformer,
5727 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5728 +            super(p, b); this.nextRight = nextRight;
5729 +            this.transformer = transformer;
5730 +            this.reducer = reducer;
5731 +        }
5732 +        @SuppressWarnings("unchecked") public final boolean exec() {
5733 +            final Fun<? super V, ? extends U> transformer =
5734 +                this.transformer;
5735 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5736 +                this.reducer;
5737 +            if (transformer == null || reducer == null)
5738 +                return abortOnNullFunction();
5739 +            try {
5740 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5741 +                    do {} while (!casPending(c = pending, c+1));
5742 +                    (rights = new MapReduceValuesTask<K,V,U>
5743 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5744 +                }
5745 +                U r = null, u;
5746 +                Object v;
5747 +                while ((v = advance()) != null) {
5748 +                    if ((u = transformer.apply((V)v)) != null)
5749 +                        r = (r == null) ? u : reducer.apply(r, u);
5750 +                }
5751 +                result = r;
5752 +                for (MapReduceValuesTask<K,V,U> t = this, s;;) {
5753 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5754 +                    if ((c = t.pending) == 0) {
5755 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5756 +                            if ((sr = s.result) != null)
5757 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5758 +                        }
5759 +                        if ((par = t.parent) == null ||
5760 +                            !(par instanceof MapReduceValuesTask)) {
5761 +                            t.quietlyComplete();
5762 +                            break;
5763 +                        }
5764 +                        t = (MapReduceValuesTask<K,V,U>)par;
5765 +                    }
5766 +                    else if (t.casPending(c, c - 1))
5767 +                        break;
5768 +                }
5769 +            } catch (Throwable ex) {
5770 +                return tryCompleteComputation(ex);
5771 +            }
5772 +            return false;
5773 +        }
5774 +        public final U getRawResult() { return result; }
5775 +    }
5776 +
5777 +    @SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
5778 +        extends BulkTask<K,V,U> {
5779 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5780 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5781 +        U result;
5782 +        MapReduceEntriesTask<K,V,U> rights, nextRight;
5783 +        MapReduceEntriesTask
5784 +            (ConcurrentHashMapV8<K,V> m,
5785 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5786 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5787 +            super(m);
5788 +            this.transformer = transformer;
5789 +            this.reducer = reducer;
5790 +        }
5791 +        MapReduceEntriesTask
5792 +            (BulkTask<K,V,?> p, int b,
5793 +             MapReduceEntriesTask<K,V,U> nextRight,
5794 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5795 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5796 +            super(p, b); this.nextRight = nextRight;
5797 +            this.transformer = transformer;
5798 +            this.reducer = reducer;
5799 +        }
5800 +        @SuppressWarnings("unchecked") public final boolean exec() {
5801 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5802 +                this.transformer;
5803 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5804 +                this.reducer;
5805 +            if (transformer == null || reducer == null)
5806 +                return abortOnNullFunction();
5807 +            try {
5808 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5809 +                    do {} while (!casPending(c = pending, c+1));
5810 +                    (rights = new MapReduceEntriesTask<K,V,U>
5811 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5812 +                }
5813 +                U r = null, u;
5814 +                Object v;
5815 +                while ((v = advance()) != null) {
5816 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5817 +                        r = (r == null) ? u : reducer.apply(r, u);
5818 +                }
5819 +                result = r;
5820 +                for (MapReduceEntriesTask<K,V,U> t = this, s;;) {
5821 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5822 +                    if ((c = t.pending) == 0) {
5823 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5824 +                            if ((sr = s.result) != null)
5825 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5826 +                        }
5827 +                        if ((par = t.parent) == null ||
5828 +                            !(par instanceof MapReduceEntriesTask)) {
5829 +                            t.quietlyComplete();
5830 +                            break;
5831 +                        }
5832 +                        t = (MapReduceEntriesTask<K,V,U>)par;
5833 +                    }
5834 +                    else if (t.casPending(c, c - 1))
5835 +                        break;
5836 +                }
5837 +            } catch (Throwable ex) {
5838 +                return tryCompleteComputation(ex);
5839 +            }
5840 +            return false;
5841 +        }
5842 +        public final U getRawResult() { return result; }
5843 +    }
5844 +
5845 +    @SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
5846 +        extends BulkTask<K,V,U> {
5847 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5848 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5849 +        U result;
5850 +        MapReduceMappingsTask<K,V,U> rights, nextRight;
5851 +        MapReduceMappingsTask
5852 +            (ConcurrentHashMapV8<K,V> m,
5853 +             BiFun<? super K, ? super V, ? extends U> transformer,
5854 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5855 +            super(m);
5856 +            this.transformer = transformer;
5857 +            this.reducer = reducer;
5858 +        }
5859 +        MapReduceMappingsTask
5860 +            (BulkTask<K,V,?> p, int b,
5861 +             MapReduceMappingsTask<K,V,U> nextRight,
5862 +             BiFun<? super K, ? super V, ? extends U> transformer,
5863 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5864 +            super(p, b); this.nextRight = nextRight;
5865 +            this.transformer = transformer;
5866 +            this.reducer = reducer;
5867 +        }
5868 +        @SuppressWarnings("unchecked") public final boolean exec() {
5869 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5870 +                this.transformer;
5871 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5872 +                this.reducer;
5873 +            if (transformer == null || reducer == null)
5874 +                return abortOnNullFunction();
5875 +            try {
5876 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5877 +                    do {} while (!casPending(c = pending, c+1));
5878 +                    (rights = new MapReduceMappingsTask<K,V,U>
5879 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5880 +                }
5881 +                U r = null, u;
5882 +                Object v;
5883 +                while ((v = advance()) != null) {
5884 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5885 +                        r = (r == null) ? u : reducer.apply(r, u);
5886 +                }
5887 +                result = r;
5888 +                for (MapReduceMappingsTask<K,V,U> t = this, s;;) {
5889 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5890 +                    if ((c = t.pending) == 0) {
5891 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5892 +                            if ((sr = s.result) != null)
5893 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5894 +                        }
5895 +                        if ((par = t.parent) == null ||
5896 +                            !(par instanceof MapReduceMappingsTask)) {
5897 +                            t.quietlyComplete();
5898 +                            break;
5899 +                        }
5900 +                        t = (MapReduceMappingsTask<K,V,U>)par;
5901 +                    }
5902 +                    else if (t.casPending(c, c - 1))
5903 +                        break;
5904 +                }
5905 +            } catch (Throwable ex) {
5906 +                return tryCompleteComputation(ex);
5907 +            }
5908 +            return false;
5909 +        }
5910 +        public final U getRawResult() { return result; }
5911 +    }
5912 +
5913 +    @SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
5914 +        extends BulkTask<K,V,Double> {
5915 +        final ObjectToDouble<? super K> transformer;
5916 +        final DoubleByDoubleToDouble reducer;
5917 +        final double basis;
5918 +        double result;
5919 +        MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5920 +        MapReduceKeysToDoubleTask
5921 +            (ConcurrentHashMapV8<K,V> m,
5922 +             ObjectToDouble<? super K> transformer,
5923 +             double basis,
5924 +             DoubleByDoubleToDouble reducer) {
5925 +            super(m);
5926 +            this.transformer = transformer;
5927 +            this.basis = basis; this.reducer = reducer;
5928 +        }
5929 +        MapReduceKeysToDoubleTask
5930 +            (BulkTask<K,V,?> p, int b,
5931 +             MapReduceKeysToDoubleTask<K,V> nextRight,
5932 +             ObjectToDouble<? super K> transformer,
5933 +             double basis,
5934 +             DoubleByDoubleToDouble reducer) {
5935 +            super(p, b); this.nextRight = nextRight;
5936 +            this.transformer = transformer;
5937 +            this.basis = basis; this.reducer = reducer;
5938 +        }
5939 +        @SuppressWarnings("unchecked") public final boolean exec() {
5940 +            final ObjectToDouble<? super K> transformer =
5941 +                this.transformer;
5942 +            final DoubleByDoubleToDouble reducer = this.reducer;
5943 +            if (transformer == null || reducer == null)
5944 +                return abortOnNullFunction();
5945 +            try {
5946 +                final double id = this.basis;
5947 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5948 +                    do {} while (!casPending(c = pending, c+1));
5949 +                    (rights = new MapReduceKeysToDoubleTask<K,V>
5950 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5951 +                }
5952 +                double r = id;
5953 +                while (advance() != null)
5954 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
5955 +                result = r;
5956 +                for (MapReduceKeysToDoubleTask<K,V> t = this, s;;) {
5957 +                    int c; BulkTask<K,V,?> par;
5958 +                    if ((c = t.pending) == 0) {
5959 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5960 +                            t.result = reducer.apply(t.result, s.result);
5961 +                        }
5962 +                        if ((par = t.parent) == null ||
5963 +                            !(par instanceof MapReduceKeysToDoubleTask)) {
5964 +                            t.quietlyComplete();
5965 +                            break;
5966 +                        }
5967 +                        t = (MapReduceKeysToDoubleTask<K,V>)par;
5968 +                    }
5969 +                    else if (t.casPending(c, c - 1))
5970 +                        break;
5971 +                }
5972 +            } catch (Throwable ex) {
5973 +                return tryCompleteComputation(ex);
5974 +            }
5975 +            return false;
5976 +        }
5977 +        public final Double getRawResult() { return result; }
5978 +    }
5979 +
5980 +    @SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
5981 +        extends BulkTask<K,V,Double> {
5982 +        final ObjectToDouble<? super V> transformer;
5983 +        final DoubleByDoubleToDouble reducer;
5984 +        final double basis;
5985 +        double result;
5986 +        MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5987 +        MapReduceValuesToDoubleTask
5988 +            (ConcurrentHashMapV8<K,V> m,
5989 +             ObjectToDouble<? super V> transformer,
5990 +             double basis,
5991 +             DoubleByDoubleToDouble reducer) {
5992 +            super(m);
5993 +            this.transformer = transformer;
5994 +            this.basis = basis; this.reducer = reducer;
5995 +        }
5996 +        MapReduceValuesToDoubleTask
5997 +            (BulkTask<K,V,?> p, int b,
5998 +             MapReduceValuesToDoubleTask<K,V> nextRight,
5999 +             ObjectToDouble<? super V> transformer,
6000 +             double basis,
6001 +             DoubleByDoubleToDouble reducer) {
6002 +            super(p, b); this.nextRight = nextRight;
6003 +            this.transformer = transformer;
6004 +            this.basis = basis; this.reducer = reducer;
6005 +        }
6006 +        @SuppressWarnings("unchecked") public final boolean exec() {
6007 +            final ObjectToDouble<? super V> transformer =
6008 +                this.transformer;
6009 +            final DoubleByDoubleToDouble reducer = this.reducer;
6010 +            if (transformer == null || reducer == null)
6011 +                return abortOnNullFunction();
6012 +            try {
6013 +                final double id = this.basis;
6014 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6015 +                    do {} while (!casPending(c = pending, c+1));
6016 +                    (rights = new MapReduceValuesToDoubleTask<K,V>
6017 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6018 +                }
6019 +                double r = id;
6020 +                Object v;
6021 +                while ((v = advance()) != null)
6022 +                    r = reducer.apply(r, transformer.apply((V)v));
6023 +                result = r;
6024 +                for (MapReduceValuesToDoubleTask<K,V> t = this, s;;) {
6025 +                    int c; BulkTask<K,V,?> par;
6026 +                    if ((c = t.pending) == 0) {
6027 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6028 +                            t.result = reducer.apply(t.result, s.result);
6029 +                        }
6030 +                        if ((par = t.parent) == null ||
6031 +                            !(par instanceof MapReduceValuesToDoubleTask)) {
6032 +                            t.quietlyComplete();
6033 +                            break;
6034 +                        }
6035 +                        t = (MapReduceValuesToDoubleTask<K,V>)par;
6036 +                    }
6037 +                    else if (t.casPending(c, c - 1))
6038 +                        break;
6039 +                }
6040 +            } catch (Throwable ex) {
6041 +                return tryCompleteComputation(ex);
6042 +            }
6043 +            return false;
6044 +        }
6045 +        public final Double getRawResult() { return result; }
6046 +    }
6047 +
6048 +    @SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6049 +        extends BulkTask<K,V,Double> {
6050 +        final ObjectToDouble<Map.Entry<K,V>> transformer;
6051 +        final DoubleByDoubleToDouble reducer;
6052 +        final double basis;
6053 +        double result;
6054 +        MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6055 +        MapReduceEntriesToDoubleTask
6056 +            (ConcurrentHashMapV8<K,V> m,
6057 +             ObjectToDouble<Map.Entry<K,V>> transformer,
6058 +             double basis,
6059 +             DoubleByDoubleToDouble reducer) {
6060 +            super(m);
6061 +            this.transformer = transformer;
6062 +            this.basis = basis; this.reducer = reducer;
6063 +        }
6064 +        MapReduceEntriesToDoubleTask
6065 +            (BulkTask<K,V,?> p, int b,
6066 +             MapReduceEntriesToDoubleTask<K,V> nextRight,
6067 +             ObjectToDouble<Map.Entry<K,V>> transformer,
6068 +             double basis,
6069 +             DoubleByDoubleToDouble reducer) {
6070 +            super(p, b); this.nextRight = nextRight;
6071 +            this.transformer = transformer;
6072 +            this.basis = basis; this.reducer = reducer;
6073 +        }
6074 +        @SuppressWarnings("unchecked") public final boolean exec() {
6075 +            final ObjectToDouble<Map.Entry<K,V>> transformer =
6076 +                this.transformer;
6077 +            final DoubleByDoubleToDouble reducer = this.reducer;
6078 +            if (transformer == null || reducer == null)
6079 +                return abortOnNullFunction();
6080 +            try {
6081 +                final double id = this.basis;
6082 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6083 +                    do {} while (!casPending(c = pending, c+1));
6084 +                    (rights = new MapReduceEntriesToDoubleTask<K,V>
6085 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6086 +                }
6087 +                double r = id;
6088 +                Object v;
6089 +                while ((v = advance()) != null)
6090 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6091 +                result = r;
6092 +                for (MapReduceEntriesToDoubleTask<K,V> t = this, s;;) {
6093 +                    int c; BulkTask<K,V,?> par;
6094 +                    if ((c = t.pending) == 0) {
6095 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6096 +                            t.result = reducer.apply(t.result, s.result);
6097 +                        }
6098 +                        if ((par = t.parent) == null ||
6099 +                            !(par instanceof MapReduceEntriesToDoubleTask)) {
6100 +                            t.quietlyComplete();
6101 +                            break;
6102 +                        }
6103 +                        t = (MapReduceEntriesToDoubleTask<K,V>)par;
6104 +                    }
6105 +                    else if (t.casPending(c, c - 1))
6106 +                        break;
6107 +                }
6108 +            } catch (Throwable ex) {
6109 +                return tryCompleteComputation(ex);
6110 +            }
6111 +            return false;
6112 +        }
6113 +        public final Double getRawResult() { return result; }
6114 +    }
6115 +
6116 +    @SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6117 +        extends BulkTask<K,V,Double> {
6118 +        final ObjectByObjectToDouble<? super K, ? super V> transformer;
6119 +        final DoubleByDoubleToDouble reducer;
6120 +        final double basis;
6121 +        double result;
6122 +        MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6123 +        MapReduceMappingsToDoubleTask
6124 +            (ConcurrentHashMapV8<K,V> m,
6125 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
6126 +             double basis,
6127 +             DoubleByDoubleToDouble reducer) {
6128 +            super(m);
6129 +            this.transformer = transformer;
6130 +            this.basis = basis; this.reducer = reducer;
6131 +        }
6132 +        MapReduceMappingsToDoubleTask
6133 +            (BulkTask<K,V,?> p, int b,
6134 +             MapReduceMappingsToDoubleTask<K,V> nextRight,
6135 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
6136 +             double basis,
6137 +             DoubleByDoubleToDouble reducer) {
6138 +            super(p, b); this.nextRight = nextRight;
6139 +            this.transformer = transformer;
6140 +            this.basis = basis; this.reducer = reducer;
6141 +        }
6142 +        @SuppressWarnings("unchecked") public final boolean exec() {
6143 +            final ObjectByObjectToDouble<? super K, ? super V> transformer =
6144 +                this.transformer;
6145 +            final DoubleByDoubleToDouble reducer = this.reducer;
6146 +            if (transformer == null || reducer == null)
6147 +                return abortOnNullFunction();
6148 +            try {
6149 +                final double id = this.basis;
6150 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6151 +                    do {} while (!casPending(c = pending, c+1));
6152 +                    (rights = new MapReduceMappingsToDoubleTask<K,V>
6153 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6154 +                }
6155 +                double r = id;
6156 +                Object v;
6157 +                while ((v = advance()) != null)
6158 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6159 +                result = r;
6160 +                for (MapReduceMappingsToDoubleTask<K,V> t = this, s;;) {
6161 +                    int c; BulkTask<K,V,?> par;
6162 +                    if ((c = t.pending) == 0) {
6163 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6164 +                            t.result = reducer.apply(t.result, s.result);
6165 +                        }
6166 +                        if ((par = t.parent) == null ||
6167 +                            !(par instanceof MapReduceMappingsToDoubleTask)) {
6168 +                            t.quietlyComplete();
6169 +                            break;
6170 +                        }
6171 +                        t = (MapReduceMappingsToDoubleTask<K,V>)par;
6172 +                    }
6173 +                    else if (t.casPending(c, c - 1))
6174 +                        break;
6175 +                }
6176 +            } catch (Throwable ex) {
6177 +                return tryCompleteComputation(ex);
6178 +            }
6179 +            return false;
6180 +        }
6181 +        public final Double getRawResult() { return result; }
6182 +    }
6183 +
6184 +    @SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6185 +        extends BulkTask<K,V,Long> {
6186 +        final ObjectToLong<? super K> transformer;
6187 +        final LongByLongToLong reducer;
6188 +        final long basis;
6189 +        long result;
6190 +        MapReduceKeysToLongTask<K,V> rights, nextRight;
6191 +        MapReduceKeysToLongTask
6192 +            (ConcurrentHashMapV8<K,V> m,
6193 +             ObjectToLong<? super K> transformer,
6194 +             long basis,
6195 +             LongByLongToLong reducer) {
6196 +            super(m);
6197 +            this.transformer = transformer;
6198 +            this.basis = basis; this.reducer = reducer;
6199 +        }
6200 +        MapReduceKeysToLongTask
6201 +            (BulkTask<K,V,?> p, int b,
6202 +             MapReduceKeysToLongTask<K,V> nextRight,
6203 +             ObjectToLong<? super K> transformer,
6204 +             long basis,
6205 +             LongByLongToLong reducer) {
6206 +            super(p, b); this.nextRight = nextRight;
6207 +            this.transformer = transformer;
6208 +            this.basis = basis; this.reducer = reducer;
6209 +        }
6210 +        @SuppressWarnings("unchecked") public final boolean exec() {
6211 +            final ObjectToLong<? super K> transformer =
6212 +                this.transformer;
6213 +            final LongByLongToLong reducer = this.reducer;
6214 +            if (transformer == null || reducer == null)
6215 +                return abortOnNullFunction();
6216 +            try {
6217 +                final long id = this.basis;
6218 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6219 +                    do {} while (!casPending(c = pending, c+1));
6220 +                    (rights = new MapReduceKeysToLongTask<K,V>
6221 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6222 +                }
6223 +                long r = id;
6224 +                while (advance() != null)
6225 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6226 +                result = r;
6227 +                for (MapReduceKeysToLongTask<K,V> t = this, s;;) {
6228 +                    int c; BulkTask<K,V,?> par;
6229 +                    if ((c = t.pending) == 0) {
6230 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6231 +                            t.result = reducer.apply(t.result, s.result);
6232 +                        }
6233 +                        if ((par = t.parent) == null ||
6234 +                            !(par instanceof MapReduceKeysToLongTask)) {
6235 +                            t.quietlyComplete();
6236 +                            break;
6237 +                        }
6238 +                        t = (MapReduceKeysToLongTask<K,V>)par;
6239 +                    }
6240 +                    else if (t.casPending(c, c - 1))
6241 +                        break;
6242 +                }
6243 +            } catch (Throwable ex) {
6244 +                return tryCompleteComputation(ex);
6245 +            }
6246 +            return false;
6247 +        }
6248 +        public final Long getRawResult() { return result; }
6249 +    }
6250 +
6251 +    @SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6252 +        extends BulkTask<K,V,Long> {
6253 +        final ObjectToLong<? super V> transformer;
6254 +        final LongByLongToLong reducer;
6255 +        final long basis;
6256 +        long result;
6257 +        MapReduceValuesToLongTask<K,V> rights, nextRight;
6258 +        MapReduceValuesToLongTask
6259 +            (ConcurrentHashMapV8<K,V> m,
6260 +             ObjectToLong<? super V> transformer,
6261 +             long basis,
6262 +             LongByLongToLong reducer) {
6263 +            super(m);
6264 +            this.transformer = transformer;
6265 +            this.basis = basis; this.reducer = reducer;
6266 +        }
6267 +        MapReduceValuesToLongTask
6268 +            (BulkTask<K,V,?> p, int b,
6269 +             MapReduceValuesToLongTask<K,V> nextRight,
6270 +             ObjectToLong<? super V> transformer,
6271 +             long basis,
6272 +             LongByLongToLong reducer) {
6273 +            super(p, b); this.nextRight = nextRight;
6274 +            this.transformer = transformer;
6275 +            this.basis = basis; this.reducer = reducer;
6276 +        }
6277 +        @SuppressWarnings("unchecked") public final boolean exec() {
6278 +            final ObjectToLong<? super V> transformer =
6279 +                this.transformer;
6280 +            final LongByLongToLong reducer = this.reducer;
6281 +            if (transformer == null || reducer == null)
6282 +                return abortOnNullFunction();
6283 +            try {
6284 +                final long id = this.basis;
6285 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6286 +                    do {} while (!casPending(c = pending, c+1));
6287 +                    (rights = new MapReduceValuesToLongTask<K,V>
6288 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6289 +                }
6290 +                long r = id;
6291 +                Object v;
6292 +                while ((v = advance()) != null)
6293 +                    r = reducer.apply(r, transformer.apply((V)v));
6294 +                result = r;
6295 +                for (MapReduceValuesToLongTask<K,V> t = this, s;;) {
6296 +                    int c; BulkTask<K,V,?> par;
6297 +                    if ((c = t.pending) == 0) {
6298 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6299 +                            t.result = reducer.apply(t.result, s.result);
6300 +                        }
6301 +                        if ((par = t.parent) == null ||
6302 +                            !(par instanceof MapReduceValuesToLongTask)) {
6303 +                            t.quietlyComplete();
6304 +                            break;
6305 +                        }
6306 +                        t = (MapReduceValuesToLongTask<K,V>)par;
6307 +                    }
6308 +                    else if (t.casPending(c, c - 1))
6309 +                        break;
6310 +                }
6311 +            } catch (Throwable ex) {
6312 +                return tryCompleteComputation(ex);
6313 +            }
6314 +            return false;
6315 +        }
6316 +        public final Long getRawResult() { return result; }
6317 +    }
6318 +
6319 +    @SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6320 +        extends BulkTask<K,V,Long> {
6321 +        final ObjectToLong<Map.Entry<K,V>> transformer;
6322 +        final LongByLongToLong reducer;
6323 +        final long basis;
6324 +        long result;
6325 +        MapReduceEntriesToLongTask<K,V> rights, nextRight;
6326 +        MapReduceEntriesToLongTask
6327 +            (ConcurrentHashMapV8<K,V> m,
6328 +             ObjectToLong<Map.Entry<K,V>> transformer,
6329 +             long basis,
6330 +             LongByLongToLong reducer) {
6331 +            super(m);
6332 +            this.transformer = transformer;
6333 +            this.basis = basis; this.reducer = reducer;
6334 +        }
6335 +        MapReduceEntriesToLongTask
6336 +            (BulkTask<K,V,?> p, int b,
6337 +             MapReduceEntriesToLongTask<K,V> nextRight,
6338 +             ObjectToLong<Map.Entry<K,V>> transformer,
6339 +             long basis,
6340 +             LongByLongToLong reducer) {
6341 +            super(p, b); this.nextRight = nextRight;
6342 +            this.transformer = transformer;
6343 +            this.basis = basis; this.reducer = reducer;
6344 +        }
6345 +        @SuppressWarnings("unchecked") public final boolean exec() {
6346 +            final ObjectToLong<Map.Entry<K,V>> transformer =
6347 +                this.transformer;
6348 +            final LongByLongToLong reducer = this.reducer;
6349 +            if (transformer == null || reducer == null)
6350 +                return abortOnNullFunction();
6351 +            try {
6352 +                final long id = this.basis;
6353 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6354 +                    do {} while (!casPending(c = pending, c+1));
6355 +                    (rights = new MapReduceEntriesToLongTask<K,V>
6356 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6357 +                }
6358 +                long r = id;
6359 +                Object v;
6360 +                while ((v = advance()) != null)
6361 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6362 +                result = r;
6363 +                for (MapReduceEntriesToLongTask<K,V> t = this, s;;) {
6364 +                    int c; BulkTask<K,V,?> par;
6365 +                    if ((c = t.pending) == 0) {
6366 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6367 +                            t.result = reducer.apply(t.result, s.result);
6368 +                        }
6369 +                        if ((par = t.parent) == null ||
6370 +                            !(par instanceof MapReduceEntriesToLongTask)) {
6371 +                            t.quietlyComplete();
6372 +                            break;
6373 +                        }
6374 +                        t = (MapReduceEntriesToLongTask<K,V>)par;
6375 +                    }
6376 +                    else if (t.casPending(c, c - 1))
6377 +                        break;
6378 +                }
6379 +            } catch (Throwable ex) {
6380 +                return tryCompleteComputation(ex);
6381 +            }
6382 +            return false;
6383 +        }
6384 +        public final Long getRawResult() { return result; }
6385 +    }
6386 +
6387 +    @SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6388 +        extends BulkTask<K,V,Long> {
6389 +        final ObjectByObjectToLong<? super K, ? super V> transformer;
6390 +        final LongByLongToLong reducer;
6391 +        final long basis;
6392 +        long result;
6393 +        MapReduceMappingsToLongTask<K,V> rights, nextRight;
6394 +        MapReduceMappingsToLongTask
6395 +            (ConcurrentHashMapV8<K,V> m,
6396 +             ObjectByObjectToLong<? super K, ? super V> transformer,
6397 +             long basis,
6398 +             LongByLongToLong reducer) {
6399 +            super(m);
6400 +            this.transformer = transformer;
6401 +            this.basis = basis; this.reducer = reducer;
6402 +        }
6403 +        MapReduceMappingsToLongTask
6404 +            (BulkTask<K,V,?> p, int b,
6405 +             MapReduceMappingsToLongTask<K,V> nextRight,
6406 +             ObjectByObjectToLong<? super K, ? super V> transformer,
6407 +             long basis,
6408 +             LongByLongToLong reducer) {
6409 +            super(p, b); this.nextRight = nextRight;
6410 +            this.transformer = transformer;
6411 +            this.basis = basis; this.reducer = reducer;
6412 +        }
6413 +        @SuppressWarnings("unchecked") public final boolean exec() {
6414 +            final ObjectByObjectToLong<? super K, ? super V> transformer =
6415 +                this.transformer;
6416 +            final LongByLongToLong reducer = this.reducer;
6417 +            if (transformer == null || reducer == null)
6418 +                return abortOnNullFunction();
6419 +            try {
6420 +                final long id = this.basis;
6421 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6422 +                    do {} while (!casPending(c = pending, c+1));
6423 +                    (rights = new MapReduceMappingsToLongTask<K,V>
6424 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6425 +                }
6426 +                long r = id;
6427 +                Object v;
6428 +                while ((v = advance()) != null)
6429 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6430 +                result = r;
6431 +                for (MapReduceMappingsToLongTask<K,V> t = this, s;;) {
6432 +                    int c; BulkTask<K,V,?> par;
6433 +                    if ((c = t.pending) == 0) {
6434 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6435 +                            t.result = reducer.apply(t.result, s.result);
6436 +                        }
6437 +                        if ((par = t.parent) == null ||
6438 +                            !(par instanceof MapReduceMappingsToLongTask)) {
6439 +                            t.quietlyComplete();
6440 +                            break;
6441 +                        }
6442 +                        t = (MapReduceMappingsToLongTask<K,V>)par;
6443 +                    }
6444 +                    else if (t.casPending(c, c - 1))
6445 +                        break;
6446 +                }
6447 +            } catch (Throwable ex) {
6448 +                return tryCompleteComputation(ex);
6449 +            }
6450 +            return false;
6451 +        }
6452 +        public final Long getRawResult() { return result; }
6453 +    }
6454 +
6455 +    @SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6456 +        extends BulkTask<K,V,Integer> {
6457 +        final ObjectToInt<? super K> transformer;
6458 +        final IntByIntToInt reducer;
6459 +        final int basis;
6460 +        int result;
6461 +        MapReduceKeysToIntTask<K,V> rights, nextRight;
6462 +        MapReduceKeysToIntTask
6463 +            (ConcurrentHashMapV8<K,V> m,
6464 +             ObjectToInt<? super K> transformer,
6465 +             int basis,
6466 +             IntByIntToInt reducer) {
6467 +            super(m);
6468 +            this.transformer = transformer;
6469 +            this.basis = basis; this.reducer = reducer;
6470 +        }
6471 +        MapReduceKeysToIntTask
6472 +            (BulkTask<K,V,?> p, int b,
6473 +             MapReduceKeysToIntTask<K,V> nextRight,
6474 +             ObjectToInt<? super K> transformer,
6475 +             int basis,
6476 +             IntByIntToInt reducer) {
6477 +            super(p, b); this.nextRight = nextRight;
6478 +            this.transformer = transformer;
6479 +            this.basis = basis; this.reducer = reducer;
6480 +        }
6481 +        @SuppressWarnings("unchecked") public final boolean exec() {
6482 +            final ObjectToInt<? super K> transformer =
6483 +                this.transformer;
6484 +            final IntByIntToInt reducer = this.reducer;
6485 +            if (transformer == null || reducer == null)
6486 +                return abortOnNullFunction();
6487 +            try {
6488 +                final int id = this.basis;
6489 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6490 +                    do {} while (!casPending(c = pending, c+1));
6491 +                    (rights = new MapReduceKeysToIntTask<K,V>
6492 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6493 +                }
6494 +                int r = id;
6495 +                while (advance() != null)
6496 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6497 +                result = r;
6498 +                for (MapReduceKeysToIntTask<K,V> t = this, s;;) {
6499 +                    int c; BulkTask<K,V,?> par;
6500 +                    if ((c = t.pending) == 0) {
6501 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6502 +                            t.result = reducer.apply(t.result, s.result);
6503 +                        }
6504 +                        if ((par = t.parent) == null ||
6505 +                            !(par instanceof MapReduceKeysToIntTask)) {
6506 +                            t.quietlyComplete();
6507 +                            break;
6508 +                        }
6509 +                        t = (MapReduceKeysToIntTask<K,V>)par;
6510 +                    }
6511 +                    else if (t.casPending(c, c - 1))
6512 +                        break;
6513 +                }
6514 +            } catch (Throwable ex) {
6515 +                return tryCompleteComputation(ex);
6516 +            }
6517 +            return false;
6518 +        }
6519 +        public final Integer getRawResult() { return result; }
6520 +    }
6521 +
6522 +    @SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6523 +        extends BulkTask<K,V,Integer> {
6524 +        final ObjectToInt<? super V> transformer;
6525 +        final IntByIntToInt reducer;
6526 +        final int basis;
6527 +        int result;
6528 +        MapReduceValuesToIntTask<K,V> rights, nextRight;
6529 +        MapReduceValuesToIntTask
6530 +            (ConcurrentHashMapV8<K,V> m,
6531 +             ObjectToInt<? super V> transformer,
6532 +             int basis,
6533 +             IntByIntToInt reducer) {
6534 +            super(m);
6535 +            this.transformer = transformer;
6536 +            this.basis = basis; this.reducer = reducer;
6537 +        }
6538 +        MapReduceValuesToIntTask
6539 +            (BulkTask<K,V,?> p, int b,
6540 +             MapReduceValuesToIntTask<K,V> nextRight,
6541 +             ObjectToInt<? super V> transformer,
6542 +             int basis,
6543 +             IntByIntToInt reducer) {
6544 +            super(p, b); this.nextRight = nextRight;
6545 +            this.transformer = transformer;
6546 +            this.basis = basis; this.reducer = reducer;
6547 +        }
6548 +        @SuppressWarnings("unchecked") public final boolean exec() {
6549 +            final ObjectToInt<? super V> transformer =
6550 +                this.transformer;
6551 +            final IntByIntToInt reducer = this.reducer;
6552 +            if (transformer == null || reducer == null)
6553 +                return abortOnNullFunction();
6554 +            try {
6555 +                final int id = this.basis;
6556 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6557 +                    do {} while (!casPending(c = pending, c+1));
6558 +                    (rights = new MapReduceValuesToIntTask<K,V>
6559 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6560 +                }
6561 +                int r = id;
6562 +                Object v;
6563 +                while ((v = advance()) != null)
6564 +                    r = reducer.apply(r, transformer.apply((V)v));
6565 +                result = r;
6566 +                for (MapReduceValuesToIntTask<K,V> t = this, s;;) {
6567 +                    int c; BulkTask<K,V,?> par;
6568 +                    if ((c = t.pending) == 0) {
6569 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6570 +                            t.result = reducer.apply(t.result, s.result);
6571 +                        }
6572 +                        if ((par = t.parent) == null ||
6573 +                            !(par instanceof MapReduceValuesToIntTask)) {
6574 +                            t.quietlyComplete();
6575 +                            break;
6576 +                        }
6577 +                        t = (MapReduceValuesToIntTask<K,V>)par;
6578 +                    }
6579 +                    else if (t.casPending(c, c - 1))
6580 +                        break;
6581 +                }
6582 +            } catch (Throwable ex) {
6583 +                return tryCompleteComputation(ex);
6584 +            }
6585 +            return false;
6586 +        }
6587 +        public final Integer getRawResult() { return result; }
6588 +    }
6589 +
6590 +    @SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6591 +        extends BulkTask<K,V,Integer> {
6592 +        final ObjectToInt<Map.Entry<K,V>> transformer;
6593 +        final IntByIntToInt reducer;
6594 +        final int basis;
6595 +        int result;
6596 +        MapReduceEntriesToIntTask<K,V> rights, nextRight;
6597 +        MapReduceEntriesToIntTask
6598 +            (ConcurrentHashMapV8<K,V> m,
6599 +             ObjectToInt<Map.Entry<K,V>> transformer,
6600 +             int basis,
6601 +             IntByIntToInt reducer) {
6602 +            super(m);
6603 +            this.transformer = transformer;
6604 +            this.basis = basis; this.reducer = reducer;
6605 +        }
6606 +        MapReduceEntriesToIntTask
6607 +            (BulkTask<K,V,?> p, int b,
6608 +             MapReduceEntriesToIntTask<K,V> nextRight,
6609 +             ObjectToInt<Map.Entry<K,V>> transformer,
6610 +             int basis,
6611 +             IntByIntToInt reducer) {
6612 +            super(p, b); this.nextRight = nextRight;
6613 +            this.transformer = transformer;
6614 +            this.basis = basis; this.reducer = reducer;
6615 +        }
6616 +        @SuppressWarnings("unchecked") public final boolean exec() {
6617 +            final ObjectToInt<Map.Entry<K,V>> transformer =
6618 +                this.transformer;
6619 +            final IntByIntToInt reducer = this.reducer;
6620 +            if (transformer == null || reducer == null)
6621 +                return abortOnNullFunction();
6622 +            try {
6623 +                final int id = this.basis;
6624 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6625 +                    do {} while (!casPending(c = pending, c+1));
6626 +                    (rights = new MapReduceEntriesToIntTask<K,V>
6627 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6628 +                }
6629 +                int r = id;
6630 +                Object v;
6631 +                while ((v = advance()) != null)
6632 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6633 +                result = r;
6634 +                for (MapReduceEntriesToIntTask<K,V> t = this, s;;) {
6635 +                    int c; BulkTask<K,V,?> par;
6636 +                    if ((c = t.pending) == 0) {
6637 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6638 +                            t.result = reducer.apply(t.result, s.result);
6639 +                        }
6640 +                        if ((par = t.parent) == null ||
6641 +                            !(par instanceof MapReduceEntriesToIntTask)) {
6642 +                            t.quietlyComplete();
6643 +                            break;
6644 +                        }
6645 +                        t = (MapReduceEntriesToIntTask<K,V>)par;
6646 +                    }
6647 +                    else if (t.casPending(c, c - 1))
6648 +                        break;
6649 +                }
6650 +            } catch (Throwable ex) {
6651 +                return tryCompleteComputation(ex);
6652 +            }
6653 +            return false;
6654 +        }
6655 +        public final Integer getRawResult() { return result; }
6656 +    }
6657 +
6658 +    @SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6659 +        extends BulkTask<K,V,Integer> {
6660 +        final ObjectByObjectToInt<? super K, ? super V> transformer;
6661 +        final IntByIntToInt reducer;
6662 +        final int basis;
6663 +        int result;
6664 +        MapReduceMappingsToIntTask<K,V> rights, nextRight;
6665 +        MapReduceMappingsToIntTask
6666 +            (ConcurrentHashMapV8<K,V> m,
6667 +             ObjectByObjectToInt<? super K, ? super V> transformer,
6668 +             int basis,
6669 +             IntByIntToInt reducer) {
6670 +            super(m);
6671 +            this.transformer = transformer;
6672 +            this.basis = basis; this.reducer = reducer;
6673 +        }
6674 +        MapReduceMappingsToIntTask
6675 +            (BulkTask<K,V,?> p, int b,
6676 +             MapReduceMappingsToIntTask<K,V> nextRight,
6677 +             ObjectByObjectToInt<? super K, ? super V> transformer,
6678 +             int basis,
6679 +             IntByIntToInt reducer) {
6680 +            super(p, b); this.nextRight = nextRight;
6681 +            this.transformer = transformer;
6682 +            this.basis = basis; this.reducer = reducer;
6683 +        }
6684 +        @SuppressWarnings("unchecked") public final boolean exec() {
6685 +            final ObjectByObjectToInt<? super K, ? super V> transformer =
6686 +                this.transformer;
6687 +            final IntByIntToInt reducer = this.reducer;
6688 +            if (transformer == null || reducer == null)
6689 +                return abortOnNullFunction();
6690 +            try {
6691 +                final int id = this.basis;
6692 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6693 +                    do {} while (!casPending(c = pending, c+1));
6694 +                    (rights = new MapReduceMappingsToIntTask<K,V>
6695 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6696 +                }
6697 +                int r = id;
6698 +                Object v;
6699 +                while ((v = advance()) != null)
6700 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6701 +                result = r;
6702 +                for (MapReduceMappingsToIntTask<K,V> t = this, s;;) {
6703 +                    int c; BulkTask<K,V,?> par;
6704 +                    if ((c = t.pending) == 0) {
6705 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6706 +                            t.result = reducer.apply(t.result, s.result);
6707 +                        }
6708 +                        if ((par = t.parent) == null ||
6709 +                            !(par instanceof MapReduceMappingsToIntTask)) {
6710 +                            t.quietlyComplete();
6711 +                            break;
6712 +                        }
6713 +                        t = (MapReduceMappingsToIntTask<K,V>)par;
6714 +                    }
6715 +                    else if (t.casPending(c, c - 1))
6716 +                        break;
6717 +                }
6718 +            } catch (Throwable ex) {
6719 +                return tryCompleteComputation(ex);
6720 +            }
6721 +            return false;
6722 +        }
6723 +        public final Integer getRawResult() { return result; }
6724 +    }
6725 +
6726 +
6727      // Unsafe mechanics
6728      private static final sun.misc.Unsafe UNSAFE;
6729      private static final long counterOffset;
6730 <    private static final long resizingOffset;
6730 >    private static final long sizeCtlOffset;
6731      private static final long ABASE;
6732      private static final int ASHIFT;
6733  
# Line 1592 | Line 6738 | public class ConcurrentHashMapV8<K, V>
6738              Class<?> k = ConcurrentHashMapV8.class;
6739              counterOffset = UNSAFE.objectFieldOffset
6740                  (k.getDeclaredField("counter"));
6741 <            resizingOffset = UNSAFE.objectFieldOffset
6742 <                (k.getDeclaredField("resizing"));
6741 >            sizeCtlOffset = UNSAFE.objectFieldOffset
6742 >                (k.getDeclaredField("sizeCtl"));
6743              Class<?> sc = Node[].class;
6744              ABASE = UNSAFE.arrayBaseOffset(sc);
6745              ss = UNSAFE.arrayIndexScale(sc);
# Line 1632 | Line 6778 | public class ConcurrentHashMapV8<K, V>
6778              }
6779          }
6780      }
1635
6781   }

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