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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.13 by jsr166, Wed Aug 31 00:22:11 2011 UTC vs.
Revision 1.62 by dl, Fri Sep 21 18:41:30 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} if there is no mapping. This is a place-holder
116 <     * 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 sometimes 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;
675 <                }
676 <                e = e.next;
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              }
364            break;
702          }
366        return null;
367    }
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 <    /** Implementation for put and putIfAbsent */
722 <    private final Object internalPut(Object k, Object v, boolean replace) {
723 <        int h = spread(k.hashCode());
724 <        Object oldVal = null;  // the previous value or null if none
725 <        Node[] tab = table;
726 <        for (;;) {
727 <            Node e; int i;
728 <            if (tab == null)
729 <                tab = grow(0);
730 <            else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
731 <                if (casTabAt(tab, i, null, new Node(h, k, v, null)))
721 >        /**
722 >         * Returns the TreeNode (or null if not found) for the given key
723 >         * starting at given root.
724 >         */
725 >        @SuppressWarnings("unchecked") final TreeNode getTreeNode
726 >            (int h, Object k, TreeNode p) {
727 >            Class<?> c = k.getClass();
728 >            while (p != null) {
729 >                int dir, ph;  Object pk; Class<?> pc;
730 >                if ((ph = p.hash) == h) {
731 >                    if ((pk = p.key) == k || k.equals(pk))
732 >                        return p;
733 >                    if (c != (pc = pk.getClass()) ||
734 >                        !(k instanceof Comparable) ||
735 >                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
736 >                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
737 >                        TreeNode r = null, s = null, pl, pr;
738 >                        if (dir >= 0) {
739 >                            if ((pl = p.left) != null && h <= pl.hash)
740 >                                s = pl;
741 >                        }
742 >                        else if ((pr = p.right) != null && h >= pr.hash)
743 >                            s = pr;
744 >                        if (s != null && (r = getTreeNode(h, k, s)) != null)
745 >                            return r;
746 >                    }
747 >                }
748 >                else
749 >                    dir = (h < ph) ? -1 : 1;
750 >                p = (dir > 0) ? p.right : p.left;
751 >            }
752 >            return null;
753 >        }
754 >
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              }
383            else if (e.hash < 0)
384                tab = (Node[])e.key;
950              else {
951 <                boolean validated = false;
952 <                boolean checkSize = false;
953 <                synchronized (e) {
954 <                    if (tabAt(tab, i) == e) {
955 <                        validated = true;
956 <                        for (Node first = e;;) {
957 <                            Object ek, ev;
958 <                            if (e.hash == h &&
959 <                                (ek = e.key) != null &&
960 <                                (ev = e.val) != null &&
961 <                                (k == ek || k.equals(ek))) {
962 <                                oldVal = ev;
963 <                                if (replace)
964 <                                    e.val = v;
965 <                                break;
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 <                            Node last = e;
986 <                            if ((e = e.next) == null) {
987 <                                last.next = new Node(h, k, v, null);
988 <                                if (last != first || tab.length <= 64)
989 <                                    checkSize = true;
990 <                                break;
985 >                            else {
986 >                                if (sr == null || !sr.red) {
987 >                                    if (sl != null)
988 >                                        sl.red = false;
989 >                                    sib.red = true;
990 >                                    rotateRight(sib);
991 >                                    sib = (xp = x.parent) == null ? null : xp.right;
992 >                                }
993 >                                if (sib != null) {
994 >                                    sib.red = (xp == null) ? false : xp.red;
995 >                                    if ((sr = sib.right) != null)
996 >                                        sr.red = false;
997 >                                }
998 >                                if (xp != null) {
999 >                                    xp.red = false;
1000 >                                    rotateLeft(xp);
1001 >                                }
1002 >                                x = root;
1003 >                            }
1004 >                        }
1005 >                    }
1006 >                    else { // symmetric
1007 >                        TreeNode sib = xpl;
1008 >                        if (sib != null && sib.red) {
1009 >                            sib.red = false;
1010 >                            xp.red = true;
1011 >                            rotateRight(xp);
1012 >                            sib = (xp = x.parent) == null ? null : xp.left;
1013 >                        }
1014 >                        if (sib == null)
1015 >                            x = xp;
1016 >                        else {
1017 >                            TreeNode sl = sib.left, sr = sib.right;
1018 >                            if ((sl == null || !sl.red) &&
1019 >                                (sr == null || !sr.red)) {
1020 >                                sib.red = true;
1021 >                                x = xp;
1022 >                            }
1023 >                            else {
1024 >                                if (sl == null || !sl.red) {
1025 >                                    if (sr != null)
1026 >                                        sr.red = false;
1027 >                                    sib.red = true;
1028 >                                    rotateLeft(sib);
1029 >                                    sib = (xp = x.parent) == null ? null : xp.left;
1030 >                                }
1031 >                                if (sib != null) {
1032 >                                    sib.red = (xp == null) ? false : xp.red;
1033 >                                    if ((sl = sib.left) != null)
1034 >                                        sl.red = false;
1035 >                                }
1036 >                                if (xp != null) {
1037 >                                    xp.red = false;
1038 >                                    rotateRight(xp);
1039 >                                }
1040 >                                x = root;
1041                              }
1042                          }
1043                      }
1044                  }
1045 <                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)
421 <            counter.increment();
422 <        return oldVal;
1113 >        return null;
1114      }
1115  
1116      /**
# Line 430 | Line 1121 | public class ConcurrentHashMapV8<K, V>
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 <                    if (tabAt(tab, i) == e) {
1171 >                try {
1172 >                    if (tabAt(tab, i) == f) {
1173                          validated = true;
1174 <                        Node pred = null;
446 <                        do {
1174 >                        for (Node e = f, pred = null;;) {
1175                              Object ek, ev;
1176 <                            if (e.hash == h &&
1177 <                                (ek = e.key) != null &&
1178 <                                (ev = e.val) != null &&
451 <                                (k == ek || k.equals(ek))) {
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 463 | Line 1190 | public class ConcurrentHashMapV8<K, V>
1190                                  break;
1191                              }
1192                              pred = e;
1193 <                        } while ((e = e.next) != null);
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 476 | 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 <        Node[] tab = table;
488 <        for (;;) {
489 <            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 <                boolean validated = false;
1252 <                synchronized (node) {
1253 <                    if (casTabAt(tab, i, null, node)) {
1254 <                        validated = true;
1255 <                        try {
1256 <                            val = f.map(k);
1257 <                            if (val != null) {
1258 <                                node.val = val;
1259 <                                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 >                            }
1266 >                        }
1267 >                    } finally {
1268 >                        t.release(0);
1269 >                    }
1270 >                    if (count != 0) {
1271 >                        if (oldVal != null)
1272 >                            return oldVal;
1273 >                        break;
1274 >                    }
1275 >                }
1276 >                else
1277 >                    tab = (Node[])fk;
1278 >            }
1279 >            else if ((fh & LOCKED) != 0) {
1280 >                checkForResize();
1281 >                f.tryAwaitLock(tab, i);
1282 >            }
1283 >            else if (f.casHash(fh, fh | LOCKED)) {
1284 >                Object oldVal = null;
1285 >                try {                        // needed in case equals() throws
1286 >                    if (tabAt(tab, i) == f) {
1287 >                        count = 1;
1288 >                        for (Node e = f;; ++count) {
1289 >                            Object ek, ev;
1290 >                            if ((e.hash & HASH_BITS) == h &&
1291 >                                (ev = e.val) != null &&
1292 >                                ((ek = e.key) == k || k.equals(ek))) {
1293 >                                oldVal = ev;
1294 >                                e.val = v;
1295 >                                break;
1296 >                            }
1297 >                            Node last = e;
1298 >                            if ((e = e.next) == null) {
1299 >                                last.next = new Node(h, k, v, null);
1300 >                                if (count >= TREE_THRESHOLD)
1301 >                                    replaceWithTreeBin(tab, i, k);
1302 >                                break;
1303                              }
504                        } finally {
505                            if (!added)
506                                setTabAt(tab, i, null);
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 (validated)
1312 >                if (count != 0) {
1313 >                    if (oldVal != null)
1314 >                        return oldVal;
1315 >                    if (tab.length <= 64)
1316 >                        count = 2;
1317                      break;
1318 +                }
1319              }
1320 <            else if (e.hash < 0)
1321 <                tab = (Node[])e.key;
1322 <            else if (Thread.holdsLock(e))
1323 <                throw new IllegalStateException("Recursive map computation");
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 validated = false;
1368 <                boolean checkSize = false;
1369 <                synchronized (e) {
1370 <                    if (tabAt(tab, i) == e) {
1371 <                        validated = true;
1372 <                        for (Node first = e;;) {
1373 <                            Object ek, ev, fv;
1374 <                            if (e.hash == h &&
1375 <                                (ek = e.key) != null &&
1367 >                Node g = f.next;
1368 >                if (g != null) { // at least 2 nodes -- search and maybe resize
1369 >                    for (Node e = g;;) {
1370 >                        Object ek, ev;
1371 >                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1372 >                            ((ek = e.key) == k || k.equals(ek)))
1373 >                            return ev;
1374 >                        if ((e = e.next) == null) {
1375 >                            checkForResize();
1376 >                            break;
1377 >                        }
1378 >                    }
1379 >                }
1380 >                if (((fh = f.hash) & LOCKED) != 0) {
1381 >                    checkForResize();
1382 >                    f.tryAwaitLock(tab, i);
1383 >                }
1384 >                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1385 >                    Object oldVal = null;
1386 >                    try {
1387 >                        if (tabAt(tab, i) == f) {
1388 >                            count = 1;
1389 >                            for (Node e = f;; ++count) {
1390 >                                Object ek, ev;
1391 >                                if ((e.hash & HASH_BITS) == h &&
1392 >                                    (ev = e.val) != null &&
1393 >                                    ((ek = e.key) == k || k.equals(ek))) {
1394 >                                    oldVal = ev;
1395 >                                    break;
1396 >                                }
1397 >                                Node last = e;
1398 >                                if ((e = e.next) == null) {
1399 >                                    last.next = new Node(h, k, v, null);
1400 >                                    if (count >= TREE_THRESHOLD)
1401 >                                        replaceWithTreeBin(tab, i, k);
1402 >                                    break;
1403 >                                }
1404 >                            }
1405 >                        }
1406 >                    } finally {
1407 >                        if (!f.casHash(fh | LOCKED, fh)) {
1408 >                            f.hash = fh;
1409 >                            synchronized (f) { f.notifyAll(); };
1410 >                        }
1411 >                    }
1412 >                    if (count != 0) {
1413 >                        if (oldVal != null)
1414 >                            return oldVal;
1415 >                        if (tab.length <= 64)
1416 >                            count = 2;
1417 >                        break;
1418 >                    }
1419 >                }
1420 >            }
1421 >        }
1422 >        counter.add(1L);
1423 >        if (count > 1)
1424 >            checkForResize();
1425 >        return null;
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 >                            checkForResize();
1499 >                            break;
1500 >                        }
1501 >                    }
1502 >                }
1503 >                if (((fh = f.hash) & LOCKED) != 0) {
1504 >                    checkForResize();
1505 >                    f.tryAwaitLock(tab, i);
1506 >                }
1507 >                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1508 >                    boolean added = false;
1509 >                    try {
1510 >                        if (tabAt(tab, i) == f) {
1511 >                            count = 1;
1512 >                            for (Node e = f;; ++count) {
1513 >                                Object ek, ev;
1514 >                                if ((e.hash & HASH_BITS) == h &&
1515 >                                    (ev = e.val) != null &&
1516 >                                    ((ek = e.key) == k || k.equals(ek))) {
1517 >                                    val = ev;
1518 >                                    break;
1519 >                                }
1520 >                                Node last = e;
1521 >                                if ((e = e.next) == null) {
1522 >                                    if ((val = mf.apply(k)) != null) {
1523 >                                        added = true;
1524 >                                        last.next = new Node(h, k, val, null);
1525 >                                        if (count >= TREE_THRESHOLD)
1526 >                                            replaceWithTreeBin(tab, i, k);
1527 >                                    }
1528 >                                    break;
1529 >                                }
1530 >                            }
1531 >                        }
1532 >                    } finally {
1533 >                        if (!f.casHash(fh | LOCKED, fh)) {
1534 >                            f.hash = fh;
1535 >                            synchronized (f) { f.notifyAll(); };
1536 >                        }
1537 >                    }
1538 >                    if (count != 0) {
1539 >                        if (!added)
1540 >                            return val;
1541 >                        if (tab.length <= 64)
1542 >                            count = 2;
1543 >                        break;
1544 >                    }
1545 >                }
1546 >            }
1547 >        }
1548 >        if (val != null) {
1549 >            counter.add(1L);
1550 >            if (count > 1)
1551 >                checkForResize();
1552 >        }
1553 >        return val;
1554 >    }
1555 >
1556 >    /** Implementation for compute */
1557 >    @SuppressWarnings("unchecked") private final Object internalCompute
1558 >        (K k, boolean onlyIfPresent, BiFun<? super K, ? super V, ? extends V> mf) {
1559 >        int h = spread(k.hashCode());
1560 >        Object val = null;
1561 >        int delta = 0;
1562 >        int count = 0;
1563 >        for (Node[] tab = table;;) {
1564 >            Node f; int i, fh; Object fk;
1565 >            if (tab == null)
1566 >                tab = initTable();
1567 >            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1568 >                if (onlyIfPresent)
1569 >                    break;
1570 >                Node node = new Node(fh = h | LOCKED, k, null, null);
1571 >                if (casTabAt(tab, i, null, node)) {
1572 >                    try {
1573 >                        count = 1;
1574 >                        if ((val = mf.apply(k, null)) != null) {
1575 >                            node.val = val;
1576 >                            delta = 1;
1577 >                        }
1578 >                    } finally {
1579 >                        if (delta == 0)
1580 >                            setTabAt(tab, i, null);
1581 >                        if (!node.casHash(fh, h)) {
1582 >                            node.hash = h;
1583 >                            synchronized (node) { node.notifyAll(); };
1584 >                        }
1585 >                    }
1586 >                }
1587 >                if (count != 0)
1588 >                    break;
1589 >            }
1590 >            else if ((fh = f.hash) == MOVED) {
1591 >                if ((fk = f.key) instanceof TreeBin) {
1592 >                    TreeBin t = (TreeBin)fk;
1593 >                    t.acquire(0);
1594 >                    try {
1595 >                        if (tabAt(tab, i) == f) {
1596 >                            count = 1;
1597 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1598 >                            Object pv = (p == null) ? null : p.val;
1599 >                            if ((val = mf.apply(k, (V)pv)) != null) {
1600 >                                if (p != null)
1601 >                                    p.val = val;
1602 >                                else {
1603 >                                    count = 2;
1604 >                                    delta = 1;
1605 >                                    t.putTreeNode(h, k, val);
1606 >                                }
1607 >                            }
1608 >                            else if (p != null) {
1609 >                                delta = -1;
1610 >                                t.deleteTreeNode(p);
1611 >                            }
1612 >                        }
1613 >                    } finally {
1614 >                        t.release(0);
1615 >                    }
1616 >                    if (count != 0)
1617 >                        break;
1618 >                }
1619 >                else
1620 >                    tab = (Node[])fk;
1621 >            }
1622 >            else if ((fh & LOCKED) != 0) {
1623 >                checkForResize();
1624 >                f.tryAwaitLock(tab, i);
1625 >            }
1626 >            else if (f.casHash(fh, fh | LOCKED)) {
1627 >                try {
1628 >                    if (tabAt(tab, i) == f) {
1629 >                        count = 1;
1630 >                        for (Node e = f, pred = null;; ++count) {
1631 >                            Object ek, ev;
1632 >                            if ((e.hash & HASH_BITS) == h &&
1633                                  (ev = e.val) != null &&
1634 <                                (k == ek || k.equals(ek))) {
1635 <                                if (replace && (fv = f.map(k)) != null)
1636 <                                    ev = e.val = fv;
1637 <                                val = (V)ev;
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 <                            Node last = e;
1648 >                            pred = e;
1649                              if ((e = e.next) == null) {
1650 <                                if ((val = f.map(k)) != null) {
1651 <                                    last.next = new Node(h, k, val, null);
1652 <                                    added = true;
1653 <                                    if (last != first || tab.length <= 64)
1654 <                                        checkSize = true;
1650 >                                if (!onlyIfPresent && (val = mf.apply(k, null)) != null) {
1651 >                                    pred.next = new Node(h, k, val, null);
1652 >                                    delta = 1;
1653 >                                    if (count >= TREE_THRESHOLD)
1654 >                                        replaceWithTreeBin(tab, i, k);
1655                                  }
1656                                  break;
1657                              }
1658                          }
1659                      }
1660 +                } finally {
1661 +                    if (!f.casHash(fh | LOCKED, fh)) {
1662 +                        f.hash = fh;
1663 +                        synchronized (f) { f.notifyAll(); };
1664 +                    }
1665                  }
1666 <                if (validated) {
1667 <                    if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1668 <                        resizing == 0 && counter.sum() >= threshold)
550 <                        grow(0);
1666 >                if (count != 0) {
1667 >                    if (tab.length <= 64)
1668 >                        count = 2;
1669                      break;
1670                  }
1671              }
1672          }
1673 <        if (added)
1674 <            counter.increment();
1673 >        if (delta != 0) {
1674 >            counter.add((long)delta);
1675 >            if (count > 1)
1676 >                checkForResize();
1677 >        }
1678          return val;
1679      }
1680  
1681 <    /*
1682 <     * Reclassifies nodes in each bin to new table.  Because we are
1683 <     * using power-of-two expansion, the elements from each bin must
1684 <     * either stay at same index, or move with a power of two
1685 <     * offset. We eliminate unnecessary node creation by catching
1686 <     * cases where old nodes can be reused because their next fields
1687 <     * won't change.  Statistically, at the default threshold, only
1688 <     * about one-sixth of them need cloning when a table doubles. The
1689 <     * nodes they replace will be garbage collectable as soon as they
1690 <     * are no longer referenced by any reader thread that may be in
1691 <     * the midst of concurrently traversing table.
1692 <     *
1693 <     * Transfers are done from the bottom up to preserve iterator
1694 <     * traversability. On each step, the old bin is locked,
1695 <     * moved/copied, and then replaced with a forwarding node.
1696 <     */
576 <    private static final void transfer(Node[] tab, Node[] nextTab) {
577 <        int n = tab.length;
578 <        int mask = nextTab.length - 1;
579 <        Node fwd = new Node(MOVED, nextTab, null, null);
580 <        for (int i = n - 1; i >= 0; --i) {
581 <            for (Node e;;) {
582 <                if ((e = tabAt(tab, i)) == null) {
583 <                    if (casTabAt(tab, i, e, fwd))
584 <                        break;
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 <                else {
1699 <                    int idx = e.hash & mask;
1700 <                    boolean validated = false;
1701 <                    synchronized (e) {
1702 <                        if (tabAt(tab, i) == e) {
1703 <                            validated = true;
1704 <                            Node lastRun = e;
1705 <                            for (Node p = e.next; p != null; p = p.next) {
1706 <                                int j = p.hash & mask;
1707 <                                if (j != idx) {
1708 <                                    idx = j;
1709 <                                    lastRun = p;
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 <                            relaxedSetTabAt(nextTab, idx, lastRun);
1718 <                            for (Node p = e; p != lastRun; p = p.next) {
1719 <                                int h = p.hash;
603 <                                int j = h & mask;
604 <                                Node r = relaxedTabAt(nextTab, j);
605 <                                relaxedSetTabAt(nextTab, j,
606 <                                                new Node(h, p.key, p.val, r));
1717 >                            else if (p != null) {
1718 >                                delta = -1;
1719 >                                t.deleteTreeNode(p);
1720                              }
608                            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
621 <     * another resize is already needed because resizings are lagging
622 <     * additions.
623 <     *
624 <     * @param sizeHint overridden capacity target (nonzero only from putAll)
625 <     * @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))
650 <                        cap = n << 1;
651 <                    else
652 <                        break;
653 <                    threshold = (int)(cap * loadFactor) - THRESHOLD_OFFSET;
654 <                    Node[] nextTab = new Node[cap];
655 <                    if (tab != null)
656 <                        transfer(tab, nextTab);
657 <                    table = nextTab;
658 <                    if (tab == null || cap >= MAXIMUM_CAPACITY ||
659 <                        ((sizeHint > 0) ? cap >= sizeHint :
660 <                         counter.sum() < threshold))
661 <                        break;
1923 >                } finally {
1924 >                    sizeCtl = sc;
1925                  }
1926 <            } finally {
664 <                resizing = 0;
1926 >                break;
1927              }
1928          }
1929 <        else if (table == null)
668 <            Thread.yield(); // lost initialization race; just spin
669 <        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) {
709 <                                e.val = null;
710 <                                ++deletions;
711 <                            }
712 <                        } while ((e = e.next) != null);
713 <                        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
719 <                        counter.add(-deletions);
720 <                        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          }
725        if (deletions != 0L)
726            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
732 <     * 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                      }
775                    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                      }
783                    else if (i + baseSize < t.length)
784                        index += baseSize;    // visit forwarded upper slots
785                    else
786                        index = ++baseIndex;
787                }
788                else {
789                    next = null;
790                    break;
2227                  }
2228              }
2229          }
2230 +        if (delta != 0)
2231 +            counter.add(delta);
2232 +    }
2233  
2234 <        final Object nextKey() {
796 <            Node e = next;
797 <            if (e == null)
798 <                throw new NoSuchElementException();
799 <            Object k = e.key;
800 <            advance((lastReturned = e).next);
801 <            return k;
802 <        }
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;
2344 >            last = null;
2345 >            map.remove(e.key);
2346          }
2347  
2348 <        /** Helper for serialization */
2349 <        final void writeEntries(java.io.ObjectOutputStream s)
832 <            throws java.io.IOException {
833 <            Node e;
834 <            while ((e = next) != null) {
835 <                s.writeObject(e.key);
836 <                s.writeObject(nextVal);
837 <                advance(e.next);
838 <            }
2348 >        public final boolean hasNext() {
2349 >            return nextVal != null || advance() != null;
2350          }
2351  
2352 <        /** Helper for containsValue */
2353 <        final boolean containsVal(Object value) {
2354 <            if (value != null) {
2355 <                Node e;
845 <                while ((e = next) != null) {
846 <                    Object v = nextVal;
847 <                    if (value == v || value.equals(v))
848 <                        return true;
849 <                    advance(e.next);
850 <                }
851 <            }
852 <            return false;
853 <        }
854 <
855 <        /** Helper for Map.hashCode */
856 <        final int mapHashCode() {
857 <            int h = 0;
858 <            Node e;
859 <            while ((e = next) != null) {
860 <                h += e.key.hashCode() ^ nextVal.hashCode();
861 <                advance(e.next);
862 <            }
863 <            return h;
864 <        }
865 <
866 <        /** Helper for Map.toString */
867 <        final String mapToString() {
868 <            Node e = next;
869 <            if (e == null)
870 <                return "{}";
871 <            StringBuilder sb = new StringBuilder();
872 <            sb.append('{');
873 <            for (;;) {
874 <                sb.append(e.key   == this ? "(this Map)" : e.key);
875 <                sb.append('=');
876 <                sb.append(nextVal == this ? "(this Map)" : nextVal);
877 <                advance(e.next);
878 <                if ((e = next) != null)
879 <                    sb.append(',').append(' ');
880 <                else
881 <                    return sb.append('}').toString();
882 <            }
883 <        }
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
890 <     * capacity, load factor and concurrency level.
891 <     *
892 <     * @param initialCapacity the initial capacity. The implementation
893 <     * performs internal sizing to accommodate this many elements.
894 <     * @param loadFactor  the load factor threshold, used to control resizing.
895 <     * Resizing may be performed when the average number of elements per
896 <     * bin exceeds this threshold.
897 <     * @param concurrencyLevel the estimated number of concurrently
898 <     * updating threads. The implementation may use this value as
899 <     * a sizing hint.
900 <     * @throws IllegalArgumentException if the initial capacity is
901 <     * negative or the load factor or concurrencyLevel are
902 <     * nonpositive.
2361 >     * Creates a new, empty map with the default initial table size (16).
2362       */
2363 <    public ConcurrentHashMapV8(int initialCapacity,
905 <                               float loadFactor, int concurrencyLevel) {
906 <        if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
907 <            throw new IllegalArgumentException();
908 <        this.initCap = initialCapacity;
909 <        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.
919     * @param loadFactor  the load factor threshold, used to control resizing.
920     * Resizing may be performed when the average number of elements per
921     * bin exceeds this threshold.
2374       * @throws IllegalArgumentException if the initial capacity of
2375 <     * elements is negative or the load factor is nonpositive
924 <     *
925 <     * @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,
933 <     * 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
936 <     * performs internal sizing to accommodate this many elements.
937 <     * @throws IllegalArgumentException if the initial capacity of
938 <     * 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.
969 <     *
970 <     * @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
978 <     * map contains more than {@code Integer.MAX_VALUE} elements, returns
979 <     * {@code Integer.MAX_VALUE}.
980 <     *
981 <     * @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 996 | Line 2487 | public class ConcurrentHashMapV8<K, V>
2487       *
2488       * @throws NullPointerException if the specified key is null
2489       */
2490 <    @SuppressWarnings("unchecked")
1000 <    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);
2494      }
2495  
2496      /**
2497 +     * Returns the value to which the specified key is mapped,
2498 +     * or the gieven defaultValue if this map contains no mapping for the key.
2499 +     *
2500 +     * @param key the key
2501 +     * @param defaultValue the value to return if this map contains
2502 +     * no mapping for the given key.
2503 +     * @return the mapping for the key, if present; else the defaultValue
2504 +     * @throws NullPointerException if the specified key is null
2505 +     */
2506 +    @SuppressWarnings("unchecked") public V getValueOrDefault(Object key, V defaultValue) {
2507 +        if (key == null)
2508 +            throw new NullPointerException();
2509 +        V v = (V) internalGet(key);
2510 +        return v == null ? defaultValue : v;
2511 +    }
2512 +
2513 +    /**
2514       * Tests if the specified object is a key in this table.
2515       *
2516       * @param  key   possible key
2517       * @return {@code true} if and only if the specified object
2518       *         is a key in this table, as determined by the
2519 <     *         {@code equals} method; {@code false} otherwise.
2519 >     *         {@code equals} method; {@code false} otherwise
2520       * @throws NullPointerException if the specified key is null
2521       */
2522      public boolean containsKey(Object key) {
# Line 1020 | Line 2527 | public class ConcurrentHashMapV8<K, V>
2527  
2528      /**
2529       * Returns {@code true} if this map maps one or more keys to the
2530 <     * specified value. Note: This method requires a full internal
2531 <     * traversal of the hash table, and so is much slower than
1025 <     * method {@code containsKey}.
2530 >     * specified value. Note: This method may require a full traversal
2531 >     * of the map, and is much slower than method {@code containsKey}.
2532       *
2533       * @param value value whose presence in this map is to be tested
2534       * @return {@code true} if this map maps one or more keys to the
# Line 1032 | Line 2538 | public class ConcurrentHashMapV8<K, V>
2538      public boolean containsValue(Object value) {
2539          if (value == null)
2540              throw new NullPointerException();
2541 <        return new HashIterator().containsVal(value);
2541 >        Object v;
2542 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2543 >        while ((v = it.advance()) != null) {
2544 >            if (v == value || value.equals(v))
2545 >                return true;
2546 >        }
2547 >        return false;
2548      }
2549  
2550      /**
# Line 1067 | Line 2579 | public class ConcurrentHashMapV8<K, V>
2579       *         {@code null} if there was no mapping for {@code key}
2580       * @throws NullPointerException if the specified key or value is null
2581       */
2582 <    @SuppressWarnings("unchecked")
1071 <    public V put(K key, V value) {
2582 >    @SuppressWarnings("unchecked") public V put(K key, V value) {
2583          if (key == null || value == null)
2584              throw new NullPointerException();
2585 <        return (V)internalPut(key, value, true);
2585 >        return (V)internalPut(key, value);
2586      }
2587  
2588      /**
# Line 1081 | Line 2592 | public class ConcurrentHashMapV8<K, V>
2592       *         or {@code null} if there was no mapping for the key
2593       * @throws NullPointerException if the specified key or value is null
2594       */
2595 <    @SuppressWarnings("unchecked")
1085 <    public V putIfAbsent(K key, V value) {
2595 >    @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
2596          if (key == null || value == null)
2597              throw new NullPointerException();
2598 <        return (V)internalPut(key, value, false);
2598 >        return (V)internalPutIfAbsent(key, value);
2599      }
2600  
2601      /**
# Line 1096 | Line 2606 | public class ConcurrentHashMapV8<K, V>
2606       * @param m mappings to be stored in this map
2607       */
2608      public void putAll(Map<? extends K, ? extends V> m) {
1099        if (m == null)
1100            throw new NullPointerException();
2609          internalPutAll(m);
2610      }
2611  
2612      /**
2613       * If the specified key is not already associated with a value,
2614 <     * computes its value using the given mappingFunction, and if
2615 <     * non-null, enters it into the map.  This is equivalent to
2616 <     *  <pre> {@code
2614 >     * computes its value using the given mappingFunction and enters
2615 >     * it into the map unless null.  This is equivalent to
2616 >     * <pre> {@code
2617       * if (map.containsKey(key))
2618       *   return map.get(key);
2619 <     * value = mappingFunction.map(key);
2619 >     * value = mappingFunction.apply(key);
2620       * if (value != null)
2621       *   map.put(key, value);
2622       * return value;}</pre>
2623       *
2624 <     * except that the action is performed atomically.  Some attempted
2625 <     * update operations on this map by other threads may be blocked
2626 <     * while computation is in progress, so the computation should be
2627 <     * short and simple, and must not attempt to update any other
2628 <     * mappings of this Map. The most appropriate usage is to
2624 >     * except that the action is performed atomically.  If the
2625 >     * function returns {@code null} no mapping is recorded. If the
2626 >     * function itself throws an (unchecked) exception, the exception
2627 >     * is rethrown to its caller, and no mapping is recorded.  Some
2628 >     * attempted update operations on this map by other threads may be
2629 >     * blocked while computation is in progress, so the computation
2630 >     * should be short and simple, and must not attempt to update any
2631 >     * other mappings of this Map. The most appropriate usage is to
2632       * construct a new object serving as an initial mapped value, or
2633       * memoized result, as in:
2634 +     *
2635       *  <pre> {@code
2636 <     * map.computeIfAbsent(key, new MappingFunction<K, V>() {
2636 >     * map.computeIfAbsent(key, new Fun<K, V>() {
2637       *   public V map(K k) { return new Value(f(k)); }});}</pre>
2638       *
2639       * @param key key with which the specified value is to be associated
2640       * @param mappingFunction the function to compute a value
2641       * @return the current (existing or computed) value associated with
2642 <     *         the specified key, or {@code null} if the computation
1131 <     *         returned {@code null}.
2642 >     *         the specified key, or null if the computed value is null.
2643       * @throws NullPointerException if the specified key or mappingFunction
2644 <     *         is null,
2644 >     *         is null
2645       * @throws IllegalStateException if the computation detectably
2646       *         attempts a recursive update to this map that would
2647 <     *         otherwise never complete.
2647 >     *         otherwise never complete
2648       * @throws RuntimeException or Error if the mappingFunction does so,
2649 <     *         in which case the mapping is left unestablished.
2649 >     *         in which case the mapping is left unestablished
2650       */
2651 <    public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2651 >    @SuppressWarnings("unchecked") public V computeIfAbsent
2652 >        (K key, Fun<? super K, ? extends V> mappingFunction) {
2653          if (key == null || mappingFunction == null)
2654              throw new NullPointerException();
2655 <        return internalCompute(key, mappingFunction, false);
2655 >        return (V)internalComputeIfAbsent(key, mappingFunction);
2656      }
2657  
2658      /**
2659 <     * Computes the value associated with the given key using the given
2660 <     * mappingFunction, and if non-null, enters it into the map.  This
1149 <     * is equivalent to
2659 >     * If the given key is present, computes a new mapping value given a key and
2660 >     * its current mapped value. This is equivalent to
2661       *  <pre> {@code
2662 <     * value = mappingFunction.map(key);
2663 <     * if (value != null)
2664 <     *   map.put(key, value);
2665 <     * else
2666 <     *   value = map.get(key);
2667 <     * return value;}</pre>
2662 >     *   if (map.containsKey(key)) {
2663 >     *     value = remappingFunction.apply(key, map.get(key));
2664 >     *     if (value != null)
2665 >     *       map.put(key, value);
2666 >     *     else
2667 >     *       map.remove(key);
2668 >     *   }
2669 >     * }</pre>
2670 >     *
2671 >     * except that the action is performed atomically.  If the
2672 >     * function returns {@code null}, the mapping is removed.  If the
2673 >     * function itself throws an (unchecked) exception, the exception
2674 >     * is rethrown to its caller, and the current mapping is left
2675 >     * unchanged.  Some attempted update operations on this map by
2676 >     * other threads may be blocked while computation is in progress,
2677 >     * so the computation should be short and simple, and must not
2678 >     * attempt to update any other mappings of this Map. For example,
2679 >     * to either create or append new messages to a value mapping:
2680       *
2681 <     * except that the action is performed atomically.  Some attempted
2682 <     * update operations on this map by other threads may be blocked
2683 <     * while computation is in progress, so the computation should be
2684 <     * short and simple, and must not attempt to update any other
2685 <     * mappings of this Map.
2681 >     * @param key key with which the specified value is to be associated
2682 >     * @param remappingFunction the function to compute a value
2683 >     * @return the new value associated with the specified key, or null if none
2684 >     * @throws NullPointerException if the specified key or remappingFunction
2685 >     *         is null
2686 >     * @throws IllegalStateException if the computation detectably
2687 >     *         attempts a recursive update to this map that would
2688 >     *         otherwise never complete
2689 >     * @throws RuntimeException or Error if the remappingFunction does so,
2690 >     *         in which case the mapping is unchanged
2691 >     */
2692 >    @SuppressWarnings("unchecked") public V computeIfPresent
2693 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2694 >        if (key == null || remappingFunction == null)
2695 >            throw new NullPointerException();
2696 >        return (V)internalCompute(key, true, remappingFunction);
2697 >    }
2698 >
2699 >    /**
2700 >     * Computes a new mapping value given a key and
2701 >     * its current mapped value (or {@code null} if there is no current
2702 >     * mapping). This is equivalent to
2703 >     *  <pre> {@code
2704 >     *   value = remappingFunction.apply(key, map.get(key));
2705 >     *   if (value != null)
2706 >     *     map.put(key, value);
2707 >     *   else
2708 >     *     map.remove(key);
2709 >     * }</pre>
2710 >     *
2711 >     * except that the action is performed atomically.  If the
2712 >     * function returns {@code null}, the mapping is removed.  If the
2713 >     * function itself throws an (unchecked) exception, the exception
2714 >     * is rethrown to its caller, and the current mapping is left
2715 >     * unchanged.  Some attempted update operations on this map by
2716 >     * other threads may be blocked while computation is in progress,
2717 >     * so the computation should be short and simple, and must not
2718 >     * attempt to update any other mappings of this Map. For example,
2719 >     * to either create or append new messages to a value mapping:
2720 >     *
2721 >     * <pre> {@code
2722 >     * Map<Key, String> map = ...;
2723 >     * final String msg = ...;
2724 >     * map.compute(key, new BiFun<Key, String, String>() {
2725 >     *   public String apply(Key k, String v) {
2726 >     *    return (v == null) ? msg : v + msg;});}}</pre>
2727       *
2728       * @param key key with which the specified value is to be associated
2729 <     * @param mappingFunction the function to compute a value
2730 <     * @return the current value associated with
2731 <     *         the specified key, or {@code null} if the computation
2732 <     *         returned {@code null} and the value was not otherwise present.
1169 <     * @throws NullPointerException if the specified key or mappingFunction
1170 <     *         is null,
2729 >     * @param remappingFunction the function to compute a value
2730 >     * @return the new value associated with the specified key, or null if none
2731 >     * @throws NullPointerException if the specified key or remappingFunction
2732 >     *         is null
2733       * @throws IllegalStateException if the computation detectably
2734       *         attempts a recursive update to this map that would
2735 <     *         otherwise never complete.
2736 <     * @throws RuntimeException or Error if the mappingFunction does so,
2737 <     *         in which case the mapping is unchanged.
2738 <     */
2739 <    public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2740 <        if (key == null || mappingFunction == null)
2735 >     *         otherwise never complete
2736 >     * @throws RuntimeException or Error if the remappingFunction does so,
2737 >     *         in which case the mapping is unchanged
2738 >     */
2739 >    @SuppressWarnings("unchecked") public V compute
2740 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2741 >        if (key == null || remappingFunction == null)
2742              throw new NullPointerException();
2743 <        return internalCompute(key, mappingFunction, true);
2743 >        return (V)internalCompute(key, false, remappingFunction);
2744 >    }
2745 >
2746 >    /**
2747 >     * If the specified key is not already associated
2748 >     * with a value, associate it with the given value.
2749 >     * Otherwise, replace the value with the results of
2750 >     * the given remapping function. This is equivalent to:
2751 >     *  <pre> {@code
2752 >     *   if (!map.containsKey(key))
2753 >     *     map.put(value);
2754 >     *   else {
2755 >     *     newValue = remappingFunction.apply(map.get(key), value);
2756 >     *     if (value != null)
2757 >     *       map.put(key, value);
2758 >     *     else
2759 >     *       map.remove(key);
2760 >     *   }
2761 >     * }</pre>
2762 >     * except that the action is performed atomically.  If the
2763 >     * function returns {@code null}, the mapping is removed.  If the
2764 >     * function itself throws an (unchecked) exception, the exception
2765 >     * is rethrown to its caller, and the current mapping is left
2766 >     * unchanged.  Some attempted update operations on this map by
2767 >     * other threads may be blocked while computation is in progress,
2768 >     * so the computation should be short and simple, and must not
2769 >     * attempt to update any other mappings of this Map.
2770 >     */
2771 >    @SuppressWarnings("unchecked") public V merge
2772 >        (K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
2773 >        if (key == null || value == null || remappingFunction == null)
2774 >            throw new NullPointerException();
2775 >        return (V)internalMerge(key, value, remappingFunction);
2776      }
2777  
2778      /**
# Line 1189 | Line 2784 | public class ConcurrentHashMapV8<K, V>
2784       *         {@code null} if there was no mapping for {@code key}
2785       * @throws NullPointerException if the specified key is null
2786       */
2787 <    @SuppressWarnings("unchecked")
1193 <    public V remove(Object key) {
2787 >    @SuppressWarnings("unchecked") public V remove(Object key) {
2788          if (key == null)
2789              throw new NullPointerException();
2790          return (V)internalReplace(key, null, null);
# Line 1227 | Line 2821 | public class ConcurrentHashMapV8<K, V>
2821       *         or {@code null} if there was no mapping for the key
2822       * @throws NullPointerException if the specified key or value is null
2823       */
2824 <    @SuppressWarnings("unchecked")
1231 <    public V replace(K key, V value) {
2824 >    @SuppressWarnings("unchecked") public V replace(K key, V value) {
2825          if (key == null || value == null)
2826              throw new NullPointerException();
2827          return (V)internalReplace(key, value, null);
# Line 1258 | Line 2851 | public class ConcurrentHashMapV8<K, V>
2851       * reflect any modifications subsequent to construction.
2852       */
2853      public Set<K> keySet() {
2854 <        Set<K> ks = keySet;
2855 <        return (ks != null) ? ks : (keySet = new KeySet());
2854 >        KeySet<K,V> ks = keySet;
2855 >        return (ks != null) ? ks : (keySet = new KeySet<K,V>(this));
2856      }
2857  
2858      /**
# Line 1279 | Line 2872 | public class ConcurrentHashMapV8<K, V>
2872       * reflect any modifications subsequent to construction.
2873       */
2874      public Collection<V> values() {
2875 <        Collection<V> vs = values;
2876 <        return (vs != null) ? vs : (values = new Values());
2875 >        Values<K,V> vs = values;
2876 >        return (vs != null) ? vs : (values = new Values<K,V>(this));
2877      }
2878  
2879      /**
# Line 1300 | Line 2893 | public class ConcurrentHashMapV8<K, V>
2893       * reflect any modifications subsequent to construction.
2894       */
2895      public Set<Map.Entry<K,V>> entrySet() {
2896 <        Set<Map.Entry<K,V>> es = entrySet;
2897 <        return (es != null) ? es : (entrySet = new EntrySet());
2896 >        EntrySet<K,V> es = entrySet;
2897 >        return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
2898      }
2899  
2900      /**
# Line 1311 | Line 2904 | public class ConcurrentHashMapV8<K, V>
2904       * @see #keySet()
2905       */
2906      public Enumeration<K> keys() {
2907 <        return new KeyIterator();
2907 >        return new KeyIterator<K,V>(this);
2908      }
2909  
2910      /**
# Line 1321 | Line 2914 | public class ConcurrentHashMapV8<K, V>
2914       * @see #values()
2915       */
2916      public Enumeration<V> elements() {
2917 <        return new ValueIterator();
2917 >        return new ValueIterator<K,V>(this);
2918 >    }
2919 >
2920 >    /**
2921 >     * Returns a partitionable iterator of the keys in this map.
2922 >     *
2923 >     * @return a partitionable iterator of the keys in this map
2924 >     */
2925 >    public Spliterator<K> keySpliterator() {
2926 >        return new KeyIterator<K,V>(this);
2927 >    }
2928 >
2929 >    /**
2930 >     * Returns a partitionable iterator of the values in this map.
2931 >     *
2932 >     * @return a partitionable iterator of the values in this map
2933 >     */
2934 >    public Spliterator<V> valueSpliterator() {
2935 >        return new ValueIterator<K,V>(this);
2936 >    }
2937 >
2938 >    /**
2939 >     * Returns a partitionable iterator of the entries in this map.
2940 >     *
2941 >     * @return a partitionable iterator of the entries in this map
2942 >     */
2943 >    public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2944 >        return new EntryIterator<K,V>(this);
2945      }
2946  
2947      /**
# Line 1332 | Line 2952 | public class ConcurrentHashMapV8<K, V>
2952       * @return the hash code value for this map
2953       */
2954      public int hashCode() {
2955 <        return new HashIterator().mapHashCode();
2955 >        int h = 0;
2956 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2957 >        Object v;
2958 >        while ((v = it.advance()) != null) {
2959 >            h += it.nextKey.hashCode() ^ v.hashCode();
2960 >        }
2961 >        return h;
2962      }
2963  
2964      /**
# Line 1347 | Line 2973 | public class ConcurrentHashMapV8<K, V>
2973       * @return a string representation of this map
2974       */
2975      public String toString() {
2976 <        return new HashIterator().mapToString();
2976 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2977 >        StringBuilder sb = new StringBuilder();
2978 >        sb.append('{');
2979 >        Object v;
2980 >        if ((v = it.advance()) != null) {
2981 >            for (;;) {
2982 >                Object k = it.nextKey;
2983 >                sb.append(k == this ? "(this Map)" : k);
2984 >                sb.append('=');
2985 >                sb.append(v == this ? "(this Map)" : v);
2986 >                if ((v = it.advance()) == null)
2987 >                    break;
2988 >                sb.append(',').append(' ');
2989 >            }
2990 >        }
2991 >        return sb.append('}').toString();
2992      }
2993  
2994      /**
# Line 1361 | Line 3002 | public class ConcurrentHashMapV8<K, V>
3002       * @return {@code true} if the specified object is equal to this map
3003       */
3004      public boolean equals(Object o) {
3005 <        if (o == this)
3006 <            return true;
3007 <        if (!(o instanceof Map))
3008 <            return false;
3009 <        Map<?,?> m = (Map<?,?>) o;
3010 <        try {
3011 <            for (Map.Entry<K,V> e : this.entrySet())
3012 <                if (! e.getValue().equals(m.get(e.getKey())))
3005 >        if (o != this) {
3006 >            if (!(o instanceof Map))
3007 >                return false;
3008 >            Map<?,?> m = (Map<?,?>) o;
3009 >            Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3010 >            Object val;
3011 >            while ((val = it.advance()) != null) {
3012 >                Object v = m.get(it.nextKey);
3013 >                if (v == null || (v != val && !v.equals(val)))
3014                      return false;
3015 +            }
3016              for (Map.Entry<?,?> e : m.entrySet()) {
3017 <                Object k = e.getKey();
3018 <                Object v = e.getValue();
3019 <                if (k == null || v == null || !v.equals(get(k)))
3017 >                Object mk, mv, v;
3018 >                if ((mk = e.getKey()) == null ||
3019 >                    (mv = e.getValue()) == null ||
3020 >                    (v = internalGet(mk)) == null ||
3021 >                    (mv != v && !mv.equals(v)))
3022                      return false;
3023              }
3024 <            return true;
3025 <        } catch (ClassCastException unused) {
3026 <            return false;
3027 <        } catch (NullPointerException unused) {
3028 <            return false;
3024 >        }
3025 >        return true;
3026 >    }
3027 >
3028 >    /* ----------------Iterators -------------- */
3029 >
3030 >    @SuppressWarnings("serial") static final class KeyIterator<K,V> extends Traverser<K,V,Object>
3031 >        implements Spliterator<K>, Enumeration<K> {
3032 >        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3033 >        KeyIterator(Traverser<K,V,Object> it) {
3034 >            super(it);
3035 >        }
3036 >        public KeyIterator<K,V> split() {
3037 >            if (last != null || (next != null && nextVal == null))
3038 >                throw new IllegalStateException();
3039 >            return new KeyIterator<K,V>(this);
3040 >        }
3041 >        @SuppressWarnings("unchecked") public final K next() {
3042 >            if (nextVal == null && advance() == null)
3043 >                throw new NoSuchElementException();
3044 >            Object k = nextKey;
3045 >            nextVal = null;
3046 >            return (K) k;
3047 >        }
3048 >
3049 >        public final K nextElement() { return next(); }
3050 >    }
3051 >
3052 >    @SuppressWarnings("serial") static final class ValueIterator<K,V> extends Traverser<K,V,Object>
3053 >        implements Spliterator<V>, Enumeration<V> {
3054 >        ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3055 >        ValueIterator(Traverser<K,V,Object> it) {
3056 >            super(it);
3057 >        }
3058 >        public ValueIterator<K,V> split() {
3059 >            if (last != null || (next != null && nextVal == null))
3060 >                throw new IllegalStateException();
3061 >            return new ValueIterator<K,V>(this);
3062 >        }
3063 >
3064 >        @SuppressWarnings("unchecked") public final V next() {
3065 >            Object v;
3066 >            if ((v = nextVal) == null && (v = advance()) == null)
3067 >                throw new NoSuchElementException();
3068 >            nextVal = null;
3069 >            return (V) v;
3070 >        }
3071 >
3072 >        public final V nextElement() { return next(); }
3073 >    }
3074 >
3075 >    @SuppressWarnings("serial") static final class EntryIterator<K,V> extends Traverser<K,V,Object>
3076 >        implements Spliterator<Map.Entry<K,V>> {
3077 >        EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3078 >        EntryIterator(Traverser<K,V,Object> it) {
3079 >            super(it);
3080 >        }
3081 >        public EntryIterator<K,V> split() {
3082 >            if (last != null || (next != null && nextVal == null))
3083 >                throw new IllegalStateException();
3084 >            return new EntryIterator<K,V>(this);
3085 >        }
3086 >
3087 >        @SuppressWarnings("unchecked") public final Map.Entry<K,V> next() {
3088 >            Object v;
3089 >            if ((v = nextVal) == null && (v = advance()) == null)
3090 >                throw new NoSuchElementException();
3091 >            Object k = nextKey;
3092 >            nextVal = null;
3093 >            return new MapEntry<K,V>((K)k, (V)v, map);
3094          }
3095      }
3096  
3097      /**
3098 <     * Custom Entry class used by EntryIterator.next(), that relays
1389 <     * setValue changes to the underlying map.
3098 >     * Exported Entry for iterators
3099       */
3100 <    final class WriteThroughEntry extends AbstractMap.SimpleEntry<K,V> {
3101 <        @SuppressWarnings("unchecked")
3102 <        WriteThroughEntry(Object k, Object v) {
3103 <            super((K)k, (V)v);
3100 >    static final class MapEntry<K,V> implements Map.Entry<K, V> {
3101 >        final K key; // non-null
3102 >        V val;       // non-null
3103 >        final ConcurrentHashMapV8<K, V> map;
3104 >        MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
3105 >            this.key = key;
3106 >            this.val = val;
3107 >            this.map = map;
3108 >        }
3109 >        public final K getKey()       { return key; }
3110 >        public final V getValue()     { return val; }
3111 >        public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3112 >        public final String toString(){ return key + "=" + val; }
3113 >
3114 >        public final boolean equals(Object o) {
3115 >            Object k, v; Map.Entry<?,?> e;
3116 >            return ((o instanceof Map.Entry) &&
3117 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3118 >                    (v = e.getValue()) != null &&
3119 >                    (k == key || k.equals(key)) &&
3120 >                    (v == val || v.equals(val)));
3121          }
3122  
3123          /**
3124           * Sets our entry's value and writes through to the map. The
3125 <         * value to return is somewhat arbitrary here. Since a
3126 <         * WriteThroughEntry does not necessarily track asynchronous
3127 <         * changes, the most recent "previous" value could be
3128 <         * different from what we return (or could even have been
3129 <         * removed in which case the put will re-establish). We do not
1404 <         * and cannot guarantee more.
3125 >         * value to return is somewhat arbitrary here. Since we do not
3126 >         * necessarily track asynchronous changes, the most recent
3127 >         * "previous" value could be different from what we return (or
3128 >         * could even have been removed in which case the put will
3129 >         * re-establish). We do not and cannot guarantee more.
3130           */
3131 <        public V setValue(V value) {
3131 >        public final V setValue(V value) {
3132              if (value == null) throw new NullPointerException();
3133 <            V v = super.setValue(value);
3134 <            ConcurrentHashMapV8.this.put(getKey(), value);
3133 >            V v = val;
3134 >            val = value;
3135 >            map.put(key, value);
3136              return v;
3137          }
3138      }
3139  
3140 <    final class KeyIterator extends HashIterator
1415 <        implements Iterator<K>, Enumeration<K> {
1416 <        @SuppressWarnings("unchecked")
1417 <        public final K next()        { return (K)super.nextKey(); }
1418 <        @SuppressWarnings("unchecked")
1419 <        public final K nextElement() { return (K)super.nextKey(); }
1420 <    }
1421 <
1422 <    final class ValueIterator extends HashIterator
1423 <        implements Iterator<V>, Enumeration<V> {
1424 <        @SuppressWarnings("unchecked")
1425 <        public final V next()        { return (V)super.nextValue(); }
1426 <        @SuppressWarnings("unchecked")
1427 <        public final V nextElement() { return (V)super.nextValue(); }
1428 <    }
3140 >    /* ----------------Views -------------- */
3141  
3142 <    final class EntryIterator extends HashIterator
3143 <        implements Iterator<Entry<K,V>> {
3144 <        public final Map.Entry<K,V> next() { return super.nextEntry(); }
3145 <    }
3142 >    /**
3143 >     * Base class for views.
3144 >     */
3145 >    static abstract class CHMView<K, V> {
3146 >        final ConcurrentHashMapV8<K, V> map;
3147 >        CHMView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
3148 >        public final int size()                 { return map.size(); }
3149 >        public final boolean isEmpty()          { return map.isEmpty(); }
3150 >        public final void clear()               { map.clear(); }
3151 >
3152 >        // implementations below rely on concrete classes supplying these
3153 >        abstract public Iterator<?> iterator();
3154 >        abstract public boolean contains(Object o);
3155 >        abstract public boolean remove(Object o);
3156 >
3157 >        private static final String oomeMsg = "Required array size too large";
3158 >
3159 >        public final Object[] toArray() {
3160 >            long sz = map.mappingCount();
3161 >            if (sz > (long)(MAX_ARRAY_SIZE))
3162 >                throw new OutOfMemoryError(oomeMsg);
3163 >            int n = (int)sz;
3164 >            Object[] r = new Object[n];
3165 >            int i = 0;
3166 >            Iterator<?> it = iterator();
3167 >            while (it.hasNext()) {
3168 >                if (i == n) {
3169 >                    if (n >= MAX_ARRAY_SIZE)
3170 >                        throw new OutOfMemoryError(oomeMsg);
3171 >                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3172 >                        n = MAX_ARRAY_SIZE;
3173 >                    else
3174 >                        n += (n >>> 1) + 1;
3175 >                    r = Arrays.copyOf(r, n);
3176 >                }
3177 >                r[i++] = it.next();
3178 >            }
3179 >            return (i == n) ? r : Arrays.copyOf(r, i);
3180 >        }
3181  
3182 <    final class KeySet extends AbstractSet<K> {
3183 <        public int size() {
3184 <            return ConcurrentHashMapV8.this.size();
3182 >        @SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
3183 >            long sz = map.mappingCount();
3184 >            if (sz > (long)(MAX_ARRAY_SIZE))
3185 >                throw new OutOfMemoryError(oomeMsg);
3186 >            int m = (int)sz;
3187 >            T[] r = (a.length >= m) ? a :
3188 >                (T[])java.lang.reflect.Array
3189 >                .newInstance(a.getClass().getComponentType(), m);
3190 >            int n = r.length;
3191 >            int i = 0;
3192 >            Iterator<?> it = iterator();
3193 >            while (it.hasNext()) {
3194 >                if (i == n) {
3195 >                    if (n >= MAX_ARRAY_SIZE)
3196 >                        throw new OutOfMemoryError(oomeMsg);
3197 >                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3198 >                        n = MAX_ARRAY_SIZE;
3199 >                    else
3200 >                        n += (n >>> 1) + 1;
3201 >                    r = Arrays.copyOf(r, n);
3202 >                }
3203 >                r[i++] = (T)it.next();
3204 >            }
3205 >            if (a == r && i < n) {
3206 >                r[i] = null; // null-terminate
3207 >                return r;
3208 >            }
3209 >            return (i == n) ? r : Arrays.copyOf(r, i);
3210          }
3211 <        public boolean isEmpty() {
3212 <            return ConcurrentHashMapV8.this.isEmpty();
3211 >
3212 >        public final int hashCode() {
3213 >            int h = 0;
3214 >            for (Iterator<?> it = iterator(); it.hasNext();)
3215 >                h += it.next().hashCode();
3216 >            return h;
3217          }
3218 <        public void clear() {
3219 <            ConcurrentHashMapV8.this.clear();
3218 >
3219 >        public final String toString() {
3220 >            StringBuilder sb = new StringBuilder();
3221 >            sb.append('[');
3222 >            Iterator<?> it = iterator();
3223 >            if (it.hasNext()) {
3224 >                for (;;) {
3225 >                    Object e = it.next();
3226 >                    sb.append(e == this ? "(this Collection)" : e);
3227 >                    if (!it.hasNext())
3228 >                        break;
3229 >                    sb.append(',').append(' ');
3230 >                }
3231 >            }
3232 >            return sb.append(']').toString();
3233          }
3234 <        public Iterator<K> iterator() {
3235 <            return new KeyIterator();
3234 >
3235 >        public final boolean containsAll(Collection<?> c) {
3236 >            if (c != this) {
3237 >                for (Iterator<?> it = c.iterator(); it.hasNext();) {
3238 >                    Object e = it.next();
3239 >                    if (e == null || !contains(e))
3240 >                        return false;
3241 >                }
3242 >            }
3243 >            return true;
3244          }
3245 <        public boolean contains(Object o) {
3246 <            return ConcurrentHashMapV8.this.containsKey(o);
3245 >
3246 >        public final boolean removeAll(Collection<?> c) {
3247 >            boolean modified = false;
3248 >            for (Iterator<?> it = iterator(); it.hasNext();) {
3249 >                if (c.contains(it.next())) {
3250 >                    it.remove();
3251 >                    modified = true;
3252 >                }
3253 >            }
3254 >            return modified;
3255          }
3256 <        public boolean remove(Object o) {
3257 <            return ConcurrentHashMapV8.this.remove(o) != null;
3256 >
3257 >        public final boolean retainAll(Collection<?> c) {
3258 >            boolean modified = false;
3259 >            for (Iterator<?> it = iterator(); it.hasNext();) {
3260 >                if (!c.contains(it.next())) {
3261 >                    it.remove();
3262 >                    modified = true;
3263 >                }
3264 >            }
3265 >            return modified;
3266          }
3267 +
3268      }
3269  
3270 <    final class Values extends AbstractCollection<V> {
3271 <        public int size() {
3272 <            return ConcurrentHashMapV8.this.size();
3270 >    static final class KeySet<K,V> extends CHMView<K,V> implements Set<K> {
3271 >        KeySet(ConcurrentHashMapV8<K, V> map)  {
3272 >            super(map);
3273          }
3274 <        public boolean isEmpty() {
3275 <            return ConcurrentHashMapV8.this.isEmpty();
3274 >        public final boolean contains(Object o) { return map.containsKey(o); }
3275 >        public final boolean remove(Object o)   { return map.remove(o) != null; }
3276 >        public final Iterator<K> iterator() {
3277 >            return new KeyIterator<K,V>(map);
3278          }
3279 <        public void clear() {
3280 <            ConcurrentHashMapV8.this.clear();
3279 >        public final boolean add(K e) {
3280 >            throw new UnsupportedOperationException();
3281          }
3282 <        public Iterator<V> iterator() {
3283 <            return new ValueIterator();
3282 >        public final boolean addAll(Collection<? extends K> c) {
3283 >            throw new UnsupportedOperationException();
3284          }
3285 <        public boolean contains(Object o) {
3286 <            return ConcurrentHashMapV8.this.containsValue(o);
3285 >        public boolean equals(Object o) {
3286 >            Set<?> c;
3287 >            return ((o instanceof Set) &&
3288 >                    ((c = (Set<?>)o) == this ||
3289 >                     (containsAll(c) && c.containsAll(this))));
3290          }
3291      }
3292  
3293 <    final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3294 <        public int size() {
3295 <            return ConcurrentHashMapV8.this.size();
3296 <        }
3297 <        public boolean isEmpty() {
3298 <            return ConcurrentHashMapV8.this.isEmpty();
3293 >
3294 >    static final class Values<K,V> extends CHMView<K,V>
3295 >        implements Collection<V> {
3296 >        Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3297 >        public final boolean contains(Object o) { return map.containsValue(o); }
3298 >        public final boolean remove(Object o) {
3299 >            if (o != null) {
3300 >                Iterator<V> it = new ValueIterator<K,V>(map);
3301 >                while (it.hasNext()) {
3302 >                    if (o.equals(it.next())) {
3303 >                        it.remove();
3304 >                        return true;
3305 >                    }
3306 >                }
3307 >            }
3308 >            return false;
3309          }
3310 <        public void clear() {
3311 <            ConcurrentHashMapV8.this.clear();
3310 >        public final Iterator<V> iterator() {
3311 >            return new ValueIterator<K,V>(map);
3312          }
3313 <        public Iterator<Map.Entry<K,V>> iterator() {
3314 <            return new EntryIterator();
3313 >        public final boolean add(V e) {
3314 >            throw new UnsupportedOperationException();
3315          }
3316 <        public boolean contains(Object o) {
3317 <            if (!(o instanceof Map.Entry))
1489 <                return false;
1490 <            Map.Entry<?,?> e = (Map.Entry<?,?>)o;
1491 <            V v = ConcurrentHashMapV8.this.get(e.getKey());
1492 <            return v != null && v.equals(e.getValue());
3316 >        public final boolean addAll(Collection<? extends V> c) {
3317 >            throw new UnsupportedOperationException();
3318          }
3319 <        public boolean remove(Object o) {
3320 <            if (!(o instanceof Map.Entry))
3321 <                return false;
3322 <            Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3323 <            return ConcurrentHashMapV8.this.remove(e.getKey(), e.getValue());
3319 >
3320 >    }
3321 >
3322 >    static final class EntrySet<K,V> extends CHMView<K,V>
3323 >        implements Set<Map.Entry<K,V>> {
3324 >        EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3325 >        public final boolean contains(Object o) {
3326 >            Object k, v, r; Map.Entry<?,?> e;
3327 >            return ((o instanceof Map.Entry) &&
3328 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3329 >                    (r = map.get(k)) != null &&
3330 >                    (v = e.getValue()) != null &&
3331 >                    (v == r || v.equals(r)));
3332 >        }
3333 >        public final boolean remove(Object o) {
3334 >            Object k, v; Map.Entry<?,?> e;
3335 >            return ((o instanceof Map.Entry) &&
3336 >                    (k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3337 >                    (v = e.getValue()) != null &&
3338 >                    map.remove(k, v));
3339 >        }
3340 >        public final Iterator<Map.Entry<K,V>> iterator() {
3341 >            return new EntryIterator<K,V>(map);
3342 >        }
3343 >        public final boolean add(Entry<K,V> e) {
3344 >            throw new UnsupportedOperationException();
3345 >        }
3346 >        public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3347 >            throw new UnsupportedOperationException();
3348 >        }
3349 >        public boolean equals(Object o) {
3350 >            Set<?> c;
3351 >            return ((o instanceof Set) &&
3352 >                    ((c = (Set<?>)o) == this ||
3353 >                     (containsAll(c) && c.containsAll(this))));
3354          }
3355      }
3356  
3357      /* ---------------- Serialization Support -------------- */
3358  
3359      /**
3360 <     * Helper class used in previous version, declared for the sake of
3361 <     * serialization compatibility
3360 >     * Stripped-down version of helper class used in previous version,
3361 >     * declared for the sake of serialization compatibility
3362       */
3363 <    static class Segment<K,V> extends java.util.concurrent.locks.ReentrantLock
1509 <        implements Serializable {
3363 >    static class Segment<K,V> implements Serializable {
3364          private static final long serialVersionUID = 2249069246763182397L;
3365          final float loadFactor;
3366          Segment(float lf) { this.loadFactor = lf; }
# Line 1521 | Line 3375 | public class ConcurrentHashMapV8<K, V>
3375       * for each key-value mapping, followed by a null pair.
3376       * The key-value mappings are emitted in no particular order.
3377       */
3378 <    @SuppressWarnings("unchecked")
3379 <    private void writeObject(java.io.ObjectOutputStream s)
1526 <            throws java.io.IOException {
3378 >    @SuppressWarnings("unchecked") private void writeObject(java.io.ObjectOutputStream s)
3379 >        throws java.io.IOException {
3380          if (segments == null) { // for serialization compatibility
3381              segments = (Segment<K,V>[])
3382                  new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3383              for (int i = 0; i < segments.length; ++i)
3384 <                segments[i] = new Segment<K,V>(loadFactor);
3384 >                segments[i] = new Segment<K,V>(LOAD_FACTOR);
3385          }
3386          s.defaultWriteObject();
3387 <        new HashIterator().writeEntries(s);
3387 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3388 >        Object v;
3389 >        while ((v = it.advance()) != null) {
3390 >            s.writeObject(it.nextKey);
3391 >            s.writeObject(v);
3392 >        }
3393          s.writeObject(null);
3394          s.writeObject(null);
3395          segments = null; // throw away
# Line 1541 | Line 3399 | public class ConcurrentHashMapV8<K, V>
3399       * Reconstitutes the instance from a stream (that is, deserializes it).
3400       * @param s the stream
3401       */
3402 <    @SuppressWarnings("unchecked")
3403 <    private void readObject(java.io.ObjectInputStream s)
1546 <            throws java.io.IOException, ClassNotFoundException {
3402 >    @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s)
3403 >        throws java.io.IOException, ClassNotFoundException {
3404          s.defaultReadObject();
1548        // find load factor in a segment, if one exists
1549        if (segments != null && segments.length != 0)
1550            this.loadFactor = segments[0].loadFactor;
1551        else
1552            this.loadFactor = DEFAULT_LOAD_FACTOR;
1553        this.initCap = DEFAULT_CAPACITY;
1554        LongAdder ct = new LongAdder(); // force final field write
1555        UNSAFE.putObjectVolatile(this, counterOffset, ct);
3405          this.segments = null; // unneeded
3406 +        // initialize transient final field
3407 +        UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
3408  
3409 <        // Read the keys and values, and put the mappings in the table
3409 >        // Create all nodes, then place in table once size is known
3410 >        long size = 0L;
3411 >        Node p = null;
3412          for (;;) {
3413 <            K key = (K) s.readObject();
3414 <            V value = (V) s.readObject();
3415 <            if (key == null)
3413 >            K k = (K) s.readObject();
3414 >            V v = (V) s.readObject();
3415 >            if (k != null && v != null) {
3416 >                int h = spread(k.hashCode());
3417 >                p = new Node(h, k, v, p);
3418 >                ++size;
3419 >            }
3420 >            else
3421                  break;
3422 <            put(key, value);
3422 >        }
3423 >        if (p != null) {
3424 >            boolean init = false;
3425 >            int n;
3426 >            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3427 >                n = MAXIMUM_CAPACITY;
3428 >            else {
3429 >                int sz = (int)size;
3430 >                n = tableSizeFor(sz + (sz >>> 1) + 1);
3431 >            }
3432 >            int sc = sizeCtl;
3433 >            boolean collide = false;
3434 >            if (n > sc &&
3435 >                UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3436 >                try {
3437 >                    if (table == null) {
3438 >                        init = true;
3439 >                        Node[] tab = new Node[n];
3440 >                        int mask = n - 1;
3441 >                        while (p != null) {
3442 >                            int j = p.hash & mask;
3443 >                            Node next = p.next;
3444 >                            Node q = p.next = tabAt(tab, j);
3445 >                            setTabAt(tab, j, p);
3446 >                            if (!collide && q != null && q.hash == p.hash)
3447 >                                collide = true;
3448 >                            p = next;
3449 >                        }
3450 >                        table = tab;
3451 >                        counter.add(size);
3452 >                        sc = n - (n >>> 2);
3453 >                    }
3454 >                } finally {
3455 >                    sizeCtl = sc;
3456 >                }
3457 >                if (collide) { // rescan and convert to TreeBins
3458 >                    Node[] tab = table;
3459 >                    for (int i = 0; i < tab.length; ++i) {
3460 >                        int c = 0;
3461 >                        for (Node e = tabAt(tab, i); e != null; e = e.next) {
3462 >                            if (++c > TREE_THRESHOLD &&
3463 >                                (e.key instanceof Comparable)) {
3464 >                                replaceWithTreeBin(tab, i, e.key);
3465 >                                break;
3466 >                            }
3467 >                        }
3468 >                    }
3469 >                }
3470 >            }
3471 >            if (!init) { // Can only happen if unsafely published.
3472 >                while (p != null) {
3473 >                    internalPut(p.key, p.val);
3474 >                    p = p.next;
3475 >                }
3476 >            }
3477          }
3478      }
3479  
3480 +
3481 +    // -------------------------------------------------------
3482 +
3483 +    // Sams
3484 +    /** Interface describing a void action of one argument */
3485 +    public interface Action<A> { void apply(A a); }
3486 +    /** Interface describing a void action of two arguments */
3487 +    public interface BiAction<A,B> { void apply(A a, B b); }
3488 +    /** Interface describing a function of one argument */
3489 +    public interface Fun<A,T> { T apply(A a); }
3490 +    /** Interface describing a function of two arguments */
3491 +    public interface BiFun<A,B,T> { T apply(A a, B b); }
3492 +    /** Interface describing a function of no arguments */
3493 +    public interface Generator<T> { T apply(); }
3494 +    /** Interface describing a function mapping its argument to a double */
3495 +    public interface ObjectToDouble<A> { double apply(A a); }
3496 +    /** Interface describing a function mapping its argument to a long */
3497 +    public interface ObjectToLong<A> { long apply(A a); }
3498 +    /** Interface describing a function mapping its argument to an int */
3499 +    public interface ObjectToInt<A> {int apply(A a); }
3500 +    /** Interface describing a function mapping two arguments to a double */
3501 +    public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
3502 +    /** Interface describing a function mapping two arguments to a long */
3503 +    public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
3504 +    /** Interface describing a function mapping two arguments to an int */
3505 +    public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }
3506 +    /** Interface describing a function mapping a double to a double */
3507 +    public interface DoubleToDouble { double apply(double a); }
3508 +    /** Interface describing a function mapping a long to a long */
3509 +    public interface LongToLong { long apply(long a); }
3510 +    /** Interface describing a function mapping an int to an int */
3511 +    public interface IntToInt { int apply(int a); }
3512 +    /** Interface describing a function mapping two doubles to a double */
3513 +    public interface DoubleByDoubleToDouble { double apply(double a, double b); }
3514 +    /** Interface describing a function mapping two longs to a long */
3515 +    public interface LongByLongToLong { long apply(long a, long b); }
3516 +    /** Interface describing a function mapping two ints to an int */
3517 +    public interface IntByIntToInt { int apply(int a, int b); }
3518 +
3519 +
3520 +    // -------------------------------------------------------
3521 +
3522 +    /**
3523 +     * Returns an extended {@link Parallel} view of this map using the
3524 +     * given executor for bulk parallel operations.
3525 +     *
3526 +     * @param executor the executor
3527 +     * @return a parallel view
3528 +     */
3529 +    public Parallel parallel(ForkJoinPool executor)  {
3530 +        return new Parallel(executor);
3531 +    }
3532 +
3533 +    /**
3534 +     * An extended view of a ConcurrentHashMap supporting bulk
3535 +     * parallel operations. These operations are designed to be
3536 +     * safely, and often sensibly, applied even with maps that are
3537 +     * being concurrently updated by other threads; for example, when
3538 +     * computing a snapshot summary of the values in a shared
3539 +     * registry.  There are three kinds of operation, each with four
3540 +     * forms, accepting functions with Keys, Values, Entries, and
3541 +     * (Key, Value) arguments and/or return values. Because the
3542 +     * elements of a ConcurrentHashMap are not ordered in any
3543 +     * particular way, and may be processed in different orders in
3544 +     * different parallel executions, the correctness of supplied
3545 +     * functions should not depend on any ordering, or on any other
3546 +     * objects or values that may transiently change while computation
3547 +     * is in progress; and except for forEach actions, should ideally
3548 +     * be side-effect-free.
3549 +     *
3550 +     * <ul>
3551 +     * <li> forEach: Perform a given action on each element.
3552 +     * A variant form applies a given transformation on each element
3553 +     * before performing the action.</li>
3554 +     *
3555 +     * <li> search: Return the first available non-null result of
3556 +     * applying a given function on each element; skipping further
3557 +     * search when a result is found.</li>
3558 +     *
3559 +     * <li> reduce: Accumulate each element.  The supplied reduction
3560 +     * function cannot rely on ordering (more formally, it should be
3561 +     * both associative and commutative).  There are five variants:
3562 +     *
3563 +     * <ul>
3564 +     *
3565 +     * <li> Plain reductions. (There is not a form of this method for
3566 +     * (key, value) function arguments since there is no corresponding
3567 +     * return type.)</li>
3568 +     *
3569 +     * <li> Mapped reductions that accumulate the results of a given
3570 +     * function applied to each element.</li>
3571 +     *
3572 +     * <li> Reductions to scalar doubles, longs, and ints, using a
3573 +     * given basis value.</li>
3574 +     *
3575 +     * </li>
3576 +     * </ul>
3577 +     * </ul>
3578 +     *
3579 +     * <p>The concurrency properties of the bulk operations follow
3580 +     * from those of ConcurrentHashMap: Any non-null result returned
3581 +     * from {@code get(key)} and related access methods bears a
3582 +     * happens-before relation with the associated insertion or
3583 +     * update.  The result of any bulk operation reflects the
3584 +     * composition of these per-element relations (but is not
3585 +     * necessarily atomic with respect to the map as a whole unless it
3586 +     * is somehow known to be quiescent).  Conversely, because keys
3587 +     * and values in the map are never null, null serves as a reliable
3588 +     * atomic indicator of the current lack of any result.  To
3589 +     * maintain this property, null serves as an implicit basis for
3590 +     * all non-scalar reduction operations. For the double, long, and
3591 +     * int versions, the basis should be one that, when combined with
3592 +     * any other value, returns that other value (more formally, it
3593 +     * should be the identity element for the reduction). Most common
3594 +     * reductions have these properties; for example, computing a sum
3595 +     * with basis 0 or a minimum with basis MAX_VALUE.
3596 +     *
3597 +     * <p>Search and transformation functions provided as arguments
3598 +     * should similarly return null to indicate the lack of any result
3599 +     * (in which case it is not used). In the case of mapped
3600 +     * reductions, this also enables transformations to serve as
3601 +     * filters, returning null (or, in the case of primitive
3602 +     * specializations, the identity basis) if the element should not
3603 +     * be combined. You can create compound transformations and
3604 +     * filterings by composing them yourself under this "null means
3605 +     * there is nothing there now" rule before using them in search or
3606 +     * reduce operations.
3607 +     *
3608 +     * <p>Methods accepting and/or returning Entry arguments maintain
3609 +     * key-value associations. They may be useful for example when
3610 +     * finding the key for the greatest value. Note that "plain" Entry
3611 +     * arguments can be supplied using {@code new
3612 +     * AbstractMap.SimpleEntry(k,v)}.
3613 +     *
3614 +     * <p> Bulk operations may complete abruptly, throwing an
3615 +     * exception encountered in the application of a supplied
3616 +     * function. Bear in mind when handling such exceptions that other
3617 +     * concurrently executing functions could also have thrown
3618 +     * exceptions, or would have done so if the first exception had
3619 +     * not occurred.
3620 +     *
3621 +     * <p>Parallel speedups compared to sequential processing are
3622 +     * common but not guaranteed.  Operations involving brief
3623 +     * functions on small maps may execute more slowly than sequential
3624 +     * loops if the underlying work to parallelize the computation is
3625 +     * more expensive than the computation itself. Similarly,
3626 +     * parallelization may not lead to much actual parallelism if all
3627 +     * processors are busy performing unrelated tasks.
3628 +     *
3629 +     * <p> All arguments to all task methods must be non-null.
3630 +     *
3631 +     * <p><em>jsr166e note: During transition, this class
3632 +     * uses nested functional interfaces with different names but the
3633 +     * same forms as those expected for JDK8.<em>
3634 +     */
3635 +    public class Parallel {
3636 +        final ForkJoinPool fjp;
3637 +
3638 +        /**
3639 +         * Returns an extended view of this map using the given
3640 +         * executor for bulk parallel operations.
3641 +         *
3642 +         * @param executor the executor
3643 +         */
3644 +        public Parallel(ForkJoinPool executor)  {
3645 +            this.fjp = executor;
3646 +        }
3647 +
3648 +        /**
3649 +         * Performs the given action for each (key, value).
3650 +         *
3651 +         * @param action the action
3652 +         */
3653 +        public void forEach(BiAction<K,V> action) {
3654 +            fjp.invoke(ForkJoinTasks.forEach
3655 +                       (ConcurrentHashMapV8.this, action));
3656 +        }
3657 +
3658 +        /**
3659 +         * Performs the given action for each non-null transformation
3660 +         * of each (key, value).
3661 +         *
3662 +         * @param transformer a function returning the transformation
3663 +         * for an element, or null of there is no transformation (in
3664 +         * which case the action is not applied).
3665 +         * @param action the action
3666 +         */
3667 +        public <U> void forEach(BiFun<? super K, ? super V, ? extends U> transformer,
3668 +                                Action<U> action) {
3669 +            fjp.invoke(ForkJoinTasks.forEach
3670 +                       (ConcurrentHashMapV8.this, transformer, action));
3671 +        }
3672 +
3673 +        /**
3674 +         * Returns a non-null result from applying the given search
3675 +         * function on each (key, value), or null if none.  Upon
3676 +         * success, further element processing is suppressed and the
3677 +         * results of any other parallel invocations of the search
3678 +         * function are ignored.
3679 +         *
3680 +         * @param searchFunction a function returning a non-null
3681 +         * result on success, else null
3682 +         * @return a non-null result from applying the given search
3683 +         * function on each (key, value), or null if none
3684 +         */
3685 +        public <U> U search(BiFun<? super K, ? super V, ? extends U> searchFunction) {
3686 +            return fjp.invoke(ForkJoinTasks.search
3687 +                              (ConcurrentHashMapV8.this, searchFunction));
3688 +        }
3689 +
3690 +        /**
3691 +         * Returns the result of accumulating the given transformation
3692 +         * of all (key, value) pairs using the given reducer to
3693 +         * combine values, or null if none.
3694 +         *
3695 +         * @param transformer a function returning the transformation
3696 +         * for an element, or null of there is no transformation (in
3697 +         * which case it is not combined).
3698 +         * @param reducer a commutative associative combining function
3699 +         * @return the result of accumulating the given transformation
3700 +         * of all (key, value) pairs
3701 +         */
3702 +        public <U> U reduce(BiFun<? super K, ? super V, ? extends U> transformer,
3703 +                            BiFun<? super U, ? super U, ? extends U> reducer) {
3704 +            return fjp.invoke(ForkJoinTasks.reduce
3705 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3706 +        }
3707 +
3708 +        /**
3709 +         * Returns the result of accumulating the given transformation
3710 +         * of all (key, value) pairs using the given reducer to
3711 +         * combine values, and the given basis as an identity value.
3712 +         *
3713 +         * @param transformer a function returning the transformation
3714 +         * for an element
3715 +         * @param basis the identity (initial default value) for the reduction
3716 +         * @param reducer a commutative associative combining function
3717 +         * @return the result of accumulating the given transformation
3718 +         * of all (key, value) pairs
3719 +         */
3720 +        public double reduceToDouble(ObjectByObjectToDouble<? super K, ? super V> transformer,
3721 +                                     double basis,
3722 +                                     DoubleByDoubleToDouble reducer) {
3723 +            return fjp.invoke(ForkJoinTasks.reduceToDouble
3724 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3725 +        }
3726 +
3727 +        /**
3728 +         * Returns the result of accumulating the given transformation
3729 +         * of all (key, value) pairs using the given reducer to
3730 +         * combine values, and the given basis as an identity value.
3731 +         *
3732 +         * @param transformer a function returning the transformation
3733 +         * for an element
3734 +         * @param basis the identity (initial default value) for the reduction
3735 +         * @param reducer a commutative associative combining function
3736 +         * @return the result of accumulating the given transformation
3737 +         * of all (key, value) pairs
3738 +         */
3739 +        public long reduceToLong(ObjectByObjectToLong<? super K, ? super V> transformer,
3740 +                                 long basis,
3741 +                                 LongByLongToLong reducer) {
3742 +            return fjp.invoke(ForkJoinTasks.reduceToLong
3743 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3744 +        }
3745 +
3746 +        /**
3747 +         * Returns the result of accumulating the given transformation
3748 +         * of all (key, value) pairs using the given reducer to
3749 +         * combine values, and the given basis as an identity value.
3750 +         *
3751 +         * @param transformer a function returning the transformation
3752 +         * for an element
3753 +         * @param basis the identity (initial default value) for the reduction
3754 +         * @param reducer a commutative associative combining function
3755 +         * @return the result of accumulating the given transformation
3756 +         * of all (key, value) pairs
3757 +         */
3758 +        public int reduceToInt(ObjectByObjectToInt<? super K, ? super V> transformer,
3759 +                               int basis,
3760 +                               IntByIntToInt reducer) {
3761 +            return fjp.invoke(ForkJoinTasks.reduceToInt
3762 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3763 +        }
3764 +
3765 +        /**
3766 +         * Performs the given action for each key.
3767 +         *
3768 +         * @param action the action
3769 +         */
3770 +        public void forEachKey(Action<K> action) {
3771 +            fjp.invoke(ForkJoinTasks.forEachKey
3772 +                       (ConcurrentHashMapV8.this, action));
3773 +        }
3774 +
3775 +        /**
3776 +         * Performs the given action for each non-null transformation
3777 +         * of each key.
3778 +         *
3779 +         * @param transformer a function returning the transformation
3780 +         * for an element, or null of there is no transformation (in
3781 +         * which case the action is not applied).
3782 +         * @param action the action
3783 +         */
3784 +        public <U> void forEachKey(Fun<? super K, ? extends U> transformer,
3785 +                                   Action<U> action) {
3786 +            fjp.invoke(ForkJoinTasks.forEachKey
3787 +                       (ConcurrentHashMapV8.this, transformer, action));
3788 +        }
3789 +
3790 +        /**
3791 +         * Returns a non-null result from applying the given search
3792 +         * function on each key, or null if none. Upon success,
3793 +         * further element processing is suppressed and the results of
3794 +         * any other parallel invocations of the search function are
3795 +         * ignored.
3796 +         *
3797 +         * @param searchFunction a function returning a non-null
3798 +         * result on success, else null
3799 +         * @return a non-null result from applying the given search
3800 +         * function on each key, or null if none
3801 +         */
3802 +        public <U> U searchKeys(Fun<? super K, ? extends U> searchFunction) {
3803 +            return fjp.invoke(ForkJoinTasks.searchKeys
3804 +                              (ConcurrentHashMapV8.this, searchFunction));
3805 +        }
3806 +
3807 +        /**
3808 +         * Returns the result of accumulating all keys using the given
3809 +         * reducer to combine values, or null if none.
3810 +         *
3811 +         * @param reducer a commutative associative combining function
3812 +         * @return the result of accumulating all keys using the given
3813 +         * reducer to combine values, or null if none
3814 +         */
3815 +        public K reduceKeys(BiFun<? super K, ? super K, ? extends K> reducer) {
3816 +            return fjp.invoke(ForkJoinTasks.reduceKeys
3817 +                              (ConcurrentHashMapV8.this, reducer));
3818 +        }
3819 +
3820 +        /**
3821 +         * Returns the result of accumulating the given transformation
3822 +         * of all keys using the given reducer to combine values, or
3823 +         * null if none.
3824 +         *
3825 +         * @param transformer a function returning the transformation
3826 +         * for an element, or null of there is no transformation (in
3827 +         * which case it is not combined).
3828 +         * @param reducer a commutative associative combining function
3829 +         * @return the result of accumulating the given transformation
3830 +         * of all keys
3831 +         */
3832 +        public <U> U reduceKeys(Fun<? super K, ? extends U> transformer,
3833 +                                BiFun<? super U, ? super U, ? extends U> reducer) {
3834 +            return fjp.invoke(ForkJoinTasks.reduceKeys
3835 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3836 +        }
3837 +
3838 +        /**
3839 +         * Returns the result of accumulating the given transformation
3840 +         * of all keys using the given reducer to combine values, and
3841 +         * the given basis as an identity value.
3842 +         *
3843 +         * @param transformer a function returning the transformation
3844 +         * for an element
3845 +         * @param basis the identity (initial default value) for the reduction
3846 +         * @param reducer a commutative associative combining function
3847 +         * @return  the result of accumulating the given transformation
3848 +         * of all keys
3849 +         */
3850 +        public double reduceKeysToDouble(ObjectToDouble<? super K> transformer,
3851 +                                         double basis,
3852 +                                         DoubleByDoubleToDouble reducer) {
3853 +            return fjp.invoke(ForkJoinTasks.reduceKeysToDouble
3854 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3855 +        }
3856 +
3857 +        /**
3858 +         * Returns the result of accumulating the given transformation
3859 +         * of all keys using the given reducer to combine values, and
3860 +         * the given basis as an identity value.
3861 +         *
3862 +         * @param transformer a function returning the transformation
3863 +         * for an element
3864 +         * @param basis the identity (initial default value) for the reduction
3865 +         * @param reducer a commutative associative combining function
3866 +         * @return the result of accumulating the given transformation
3867 +         * of all keys
3868 +         */
3869 +        public long reduceKeysToLong(ObjectToLong<? super K> transformer,
3870 +                                     long basis,
3871 +                                     LongByLongToLong reducer) {
3872 +            return fjp.invoke(ForkJoinTasks.reduceKeysToLong
3873 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3874 +        }
3875 +
3876 +        /**
3877 +         * Returns the result of accumulating the given transformation
3878 +         * of all keys using the given reducer to combine values, and
3879 +         * the given basis as an identity value.
3880 +         *
3881 +         * @param transformer a function returning the transformation
3882 +         * for an element
3883 +         * @param basis the identity (initial default value) for the reduction
3884 +         * @param reducer a commutative associative combining function
3885 +         * @return the result of accumulating the given transformation
3886 +         * of all keys
3887 +         */
3888 +        public int reduceKeysToInt(ObjectToInt<? super K> transformer,
3889 +                                   int basis,
3890 +                                   IntByIntToInt reducer) {
3891 +            return fjp.invoke(ForkJoinTasks.reduceKeysToInt
3892 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3893 +        }
3894 +
3895 +        /**
3896 +         * Performs the given action for each value.
3897 +         *
3898 +         * @param action the action
3899 +         */
3900 +        public void forEachValue(Action<V> action) {
3901 +            fjp.invoke(ForkJoinTasks.forEachValue
3902 +                       (ConcurrentHashMapV8.this, action));
3903 +        }
3904 +
3905 +        /**
3906 +         * Performs the given action for each non-null transformation
3907 +         * of each value.
3908 +         *
3909 +         * @param transformer a function returning the transformation
3910 +         * for an element, or null of there is no transformation (in
3911 +         * which case the action is not applied).
3912 +         */
3913 +        public <U> void forEachValue(Fun<? super V, ? extends U> transformer,
3914 +                                     Action<U> action) {
3915 +            fjp.invoke(ForkJoinTasks.forEachValue
3916 +                       (ConcurrentHashMapV8.this, transformer, action));
3917 +        }
3918 +
3919 +        /**
3920 +         * Returns a non-null result from applying the given search
3921 +         * function on each value, or null if none.  Upon success,
3922 +         * further element processing is suppressed and the results of
3923 +         * any other parallel invocations of the search function are
3924 +         * ignored.
3925 +         *
3926 +         * @param searchFunction a function returning a non-null
3927 +         * result on success, else null
3928 +         * @return a non-null result from applying the given search
3929 +         * function on each value, or null if none
3930 +         *
3931 +         */
3932 +        public <U> U searchValues(Fun<? super V, ? extends U> searchFunction) {
3933 +            return fjp.invoke(ForkJoinTasks.searchValues
3934 +                              (ConcurrentHashMapV8.this, searchFunction));
3935 +        }
3936 +
3937 +        /**
3938 +         * Returns the result of accumulating all values using the
3939 +         * given reducer to combine values, or null if none.
3940 +         *
3941 +         * @param reducer a commutative associative combining function
3942 +         * @return  the result of accumulating all values
3943 +         */
3944 +        public V reduceValues(BiFun<? super V, ? super V, ? extends V> reducer) {
3945 +            return fjp.invoke(ForkJoinTasks.reduceValues
3946 +                              (ConcurrentHashMapV8.this, reducer));
3947 +        }
3948 +
3949 +        /**
3950 +         * Returns the result of accumulating the given transformation
3951 +         * of all values using the given reducer to combine values, or
3952 +         * null if none.
3953 +         *
3954 +         * @param transformer a function returning the transformation
3955 +         * for an element, or null of there is no transformation (in
3956 +         * which case it is not combined).
3957 +         * @param reducer a commutative associative combining function
3958 +         * @return the result of accumulating the given transformation
3959 +         * of all values
3960 +         */
3961 +        public <U> U reduceValues(Fun<? super V, ? extends U> transformer,
3962 +                                  BiFun<? super U, ? super U, ? extends U> reducer) {
3963 +            return fjp.invoke(ForkJoinTasks.reduceValues
3964 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3965 +        }
3966 +
3967 +        /**
3968 +         * Returns the result of accumulating the given transformation
3969 +         * of all values using the given reducer to combine values,
3970 +         * and the given basis as an identity value.
3971 +         *
3972 +         * @param transformer a function returning the transformation
3973 +         * for an element
3974 +         * @param basis the identity (initial default value) for the reduction
3975 +         * @param reducer a commutative associative combining function
3976 +         * @return the result of accumulating the given transformation
3977 +         * of all values
3978 +         */
3979 +        public double reduceValuesToDouble(ObjectToDouble<? super V> transformer,
3980 +                                           double basis,
3981 +                                           DoubleByDoubleToDouble reducer) {
3982 +            return fjp.invoke(ForkJoinTasks.reduceValuesToDouble
3983 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3984 +        }
3985 +
3986 +        /**
3987 +         * Returns the result of accumulating the given transformation
3988 +         * of all values using the given reducer to combine values,
3989 +         * and the given basis as an identity value.
3990 +         *
3991 +         * @param transformer a function returning the transformation
3992 +         * for an element
3993 +         * @param basis the identity (initial default value) for the reduction
3994 +         * @param reducer a commutative associative combining function
3995 +         * @return the result of accumulating the given transformation
3996 +         * of all values
3997 +         */
3998 +        public long reduceValuesToLong(ObjectToLong<? super V> transformer,
3999 +                                       long basis,
4000 +                                       LongByLongToLong reducer) {
4001 +            return fjp.invoke(ForkJoinTasks.reduceValuesToLong
4002 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4003 +        }
4004 +
4005 +        /**
4006 +         * Returns the result of accumulating the given transformation
4007 +         * of all values using the given reducer to combine values,
4008 +         * and the given basis as an identity value.
4009 +         *
4010 +         * @param transformer a function returning the transformation
4011 +         * for an element
4012 +         * @param basis the identity (initial default value) for the reduction
4013 +         * @param reducer a commutative associative combining function
4014 +         * @return the result of accumulating the given transformation
4015 +         * of all values
4016 +         */
4017 +        public int reduceValuesToInt(ObjectToInt<? super V> transformer,
4018 +                                     int basis,
4019 +                                     IntByIntToInt reducer) {
4020 +            return fjp.invoke(ForkJoinTasks.reduceValuesToInt
4021 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4022 +        }
4023 +
4024 +        /**
4025 +         * Performs the given action for each entry.
4026 +         *
4027 +         * @param action the action
4028 +         */
4029 +        public void forEachEntry(Action<Map.Entry<K,V>> action) {
4030 +            fjp.invoke(ForkJoinTasks.forEachEntry
4031 +                       (ConcurrentHashMapV8.this, action));
4032 +        }
4033 +
4034 +        /**
4035 +         * Performs the given action for each non-null transformation
4036 +         * of each entry.
4037 +         *
4038 +         * @param transformer a function returning the transformation
4039 +         * for an element, or null of there is no transformation (in
4040 +         * which case the action is not applied).
4041 +         * @param action the action
4042 +         */
4043 +        public <U> void forEachEntry(Fun<Map.Entry<K,V>, ? extends U> transformer,
4044 +                                     Action<U> action) {
4045 +            fjp.invoke(ForkJoinTasks.forEachEntry
4046 +                       (ConcurrentHashMapV8.this, transformer, action));
4047 +        }
4048 +
4049 +        /**
4050 +         * Returns a non-null result from applying the given search
4051 +         * function on each entry, or null if none.  Upon success,
4052 +         * further element processing is suppressed and the results of
4053 +         * any other parallel invocations of the search function are
4054 +         * ignored.
4055 +         *
4056 +         * @param searchFunction a function returning a non-null
4057 +         * result on success, else null
4058 +         * @return a non-null result from applying the given search
4059 +         * function on each entry, or null if none
4060 +         */
4061 +        public <U> U searchEntries(Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4062 +            return fjp.invoke(ForkJoinTasks.searchEntries
4063 +                              (ConcurrentHashMapV8.this, searchFunction));
4064 +        }
4065 +
4066 +        /**
4067 +         * Returns the result of accumulating all entries using the
4068 +         * given reducer to combine values, or null if none.
4069 +         *
4070 +         * @param reducer a commutative associative combining function
4071 +         * @return the result of accumulating all entries
4072 +         */
4073 +        public Map.Entry<K,V> reduceEntries(BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4074 +            return fjp.invoke(ForkJoinTasks.reduceEntries
4075 +                              (ConcurrentHashMapV8.this, reducer));
4076 +        }
4077 +
4078 +        /**
4079 +         * Returns the result of accumulating the given transformation
4080 +         * of all entries using the given reducer to combine values,
4081 +         * or null if none.
4082 +         *
4083 +         * @param transformer a function returning the transformation
4084 +         * for an element, or null of there is no transformation (in
4085 +         * which case it is not combined).
4086 +         * @param reducer a commutative associative combining function
4087 +         * @return the result of accumulating the given transformation
4088 +         * of all entries
4089 +         */
4090 +        public <U> U reduceEntries(Fun<Map.Entry<K,V>, ? extends U> transformer,
4091 +                                   BiFun<? super U, ? super U, ? extends U> reducer) {
4092 +            return fjp.invoke(ForkJoinTasks.reduceEntries
4093 +                              (ConcurrentHashMapV8.this, transformer, reducer));
4094 +        }
4095 +
4096 +        /**
4097 +         * Returns the result of accumulating the given transformation
4098 +         * of all entries using the given reducer to combine values,
4099 +         * and the given basis as an identity value.
4100 +         *
4101 +         * @param transformer a function returning the transformation
4102 +         * for an element
4103 +         * @param basis the identity (initial default value) for the reduction
4104 +         * @param reducer a commutative associative combining function
4105 +         * @return the result of accumulating the given transformation
4106 +         * of all entries
4107 +         */
4108 +        public double reduceEntriesToDouble(ObjectToDouble<Map.Entry<K,V>> transformer,
4109 +                                            double basis,
4110 +                                            DoubleByDoubleToDouble reducer) {
4111 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToDouble
4112 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4113 +        }
4114 +
4115 +        /**
4116 +         * Returns the result of accumulating the given transformation
4117 +         * of all entries using the given reducer to combine values,
4118 +         * and the given basis as an identity value.
4119 +         *
4120 +         * @param transformer a function returning the transformation
4121 +         * for an element
4122 +         * @param basis the identity (initial default value) for the reduction
4123 +         * @param reducer a commutative associative combining function
4124 +         * @return  the result of accumulating the given transformation
4125 +         * of all entries
4126 +         */
4127 +        public long reduceEntriesToLong(ObjectToLong<Map.Entry<K,V>> transformer,
4128 +                                        long basis,
4129 +                                        LongByLongToLong reducer) {
4130 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToLong
4131 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4132 +        }
4133 +
4134 +        /**
4135 +         * Returns the result of accumulating the given transformation
4136 +         * of all entries using the given reducer to combine values,
4137 +         * and the given basis as an identity value.
4138 +         *
4139 +         * @param transformer a function returning the transformation
4140 +         * for an element
4141 +         * @param basis the identity (initial default value) for the reduction
4142 +         * @param reducer a commutative associative combining function
4143 +         * @return the result of accumulating the given transformation
4144 +         * of all entries
4145 +         */
4146 +        public int reduceEntriesToInt(ObjectToInt<Map.Entry<K,V>> transformer,
4147 +                                      int basis,
4148 +                                      IntByIntToInt reducer) {
4149 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToInt
4150 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4151 +        }
4152 +    }
4153 +
4154 +    // ---------------------------------------------------------------------
4155 +
4156 +    /**
4157 +     * Predefined tasks for performing bulk parallel operations on
4158 +     * ConcurrentHashMaps. These tasks follow the forms and rules used
4159 +     * in class {@link Parallel}. Each method has the same name, but
4160 +     * returns a task rather than invoking it. These methods may be
4161 +     * useful in custom applications such as submitting a task without
4162 +     * waiting for completion, or combining with other tasks.
4163 +     */
4164 +    public static class ForkJoinTasks {
4165 +        private ForkJoinTasks() {}
4166 +
4167 +        /**
4168 +         * Returns a task that when invoked, performs the given
4169 +         * action for each (key, value)
4170 +         *
4171 +         * @param map the map
4172 +         * @param action the action
4173 +         * @return the task
4174 +         */
4175 +        public static <K,V> ForkJoinTask<Void> forEach
4176 +            (ConcurrentHashMapV8<K,V> map,
4177 +             BiAction<K,V> action) {
4178 +            if (action == null) throw new NullPointerException();
4179 +            return new ForEachMappingTask<K,V>(map, action);
4180 +        }
4181 +
4182 +        /**
4183 +         * Returns a task that when invoked, performs the given
4184 +         * action for each non-null transformation of each (key, value)
4185 +         *
4186 +         * @param map the map
4187 +         * @param transformer a function returning the transformation
4188 +         * for an element, or null of there is no transformation (in
4189 +         * which case the action is not applied).
4190 +         * @param action the action
4191 +         * @return the task
4192 +         */
4193 +        public static <K,V,U> ForkJoinTask<Void> forEach
4194 +            (ConcurrentHashMapV8<K,V> map,
4195 +             BiFun<? super K, ? super V, ? extends U> transformer,
4196 +             Action<U> action) {
4197 +            if (transformer == null || action == null)
4198 +                throw new NullPointerException();
4199 +            return new ForEachTransformedMappingTask<K,V,U>
4200 +                (map, transformer, action);
4201 +        }
4202 +
4203 +        /**
4204 +         * Returns a task that when invoked, returns a non-null result
4205 +         * from applying the given search function on each (key,
4206 +         * value), or null if none. Upon success, further element
4207 +         * processing is suppressed and the results of any other
4208 +         * parallel invocations of the search function are ignored.
4209 +         *
4210 +         * @param map the map
4211 +         * @param searchFunction a function returning a non-null
4212 +         * result on success, else null
4213 +         * @return the task
4214 +         */
4215 +        public static <K,V,U> ForkJoinTask<U> search
4216 +            (ConcurrentHashMapV8<K,V> map,
4217 +             BiFun<? super K, ? super V, ? extends U> searchFunction) {
4218 +            if (searchFunction == null) throw new NullPointerException();
4219 +            return new SearchMappingsTask<K,V,U>
4220 +                (map, searchFunction,
4221 +                 new AtomicReference<U>());
4222 +        }
4223 +
4224 +        /**
4225 +         * Returns a task that when invoked, returns the result of
4226 +         * accumulating the given transformation of all (key, value) pairs
4227 +         * using the given reducer to combine values, or null if none.
4228 +         *
4229 +         * @param map the map
4230 +         * @param transformer a function returning the transformation
4231 +         * for an element, or null of there is no transformation (in
4232 +         * which case it is not combined).
4233 +         * @param reducer a commutative associative combining function
4234 +         * @return the task
4235 +         */
4236 +        public static <K,V,U> ForkJoinTask<U> reduce
4237 +            (ConcurrentHashMapV8<K,V> map,
4238 +             BiFun<? super K, ? super V, ? extends U> transformer,
4239 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4240 +            if (transformer == null || reducer == null)
4241 +                throw new NullPointerException();
4242 +            return new MapReduceMappingsTask<K,V,U>
4243 +                (map, transformer, reducer);
4244 +        }
4245 +
4246 +        /**
4247 +         * Returns a task that when invoked, returns the result of
4248 +         * accumulating the given transformation of all (key, value) pairs
4249 +         * using the given reducer to combine values, and the given
4250 +         * basis as an identity value.
4251 +         *
4252 +         * @param map the map
4253 +         * @param transformer a function returning the transformation
4254 +         * for an element
4255 +         * @param basis the identity (initial default value) for the reduction
4256 +         * @param reducer a commutative associative combining function
4257 +         * @return the task
4258 +         */
4259 +        public static <K,V> ForkJoinTask<Double> reduceToDouble
4260 +            (ConcurrentHashMapV8<K,V> map,
4261 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
4262 +             double basis,
4263 +             DoubleByDoubleToDouble reducer) {
4264 +            if (transformer == null || reducer == null)
4265 +                throw new NullPointerException();
4266 +            return new MapReduceMappingsToDoubleTask<K,V>
4267 +                (map, transformer, basis, reducer);
4268 +        }
4269 +
4270 +        /**
4271 +         * Returns a task that when invoked, returns the result of
4272 +         * accumulating the given transformation of all (key, value) pairs
4273 +         * using the given reducer to combine values, and the given
4274 +         * basis as an identity value.
4275 +         *
4276 +         * @param map the map
4277 +         * @param transformer a function returning the transformation
4278 +         * for an element
4279 +         * @param basis the identity (initial default value) for the reduction
4280 +         * @param reducer a commutative associative combining function
4281 +         * @return the task
4282 +         */
4283 +        public static <K,V> ForkJoinTask<Long> reduceToLong
4284 +            (ConcurrentHashMapV8<K,V> map,
4285 +             ObjectByObjectToLong<? super K, ? super V> transformer,
4286 +             long basis,
4287 +             LongByLongToLong reducer) {
4288 +            if (transformer == null || reducer == null)
4289 +                throw new NullPointerException();
4290 +            return new MapReduceMappingsToLongTask<K,V>
4291 +                (map, transformer, basis, reducer);
4292 +        }
4293 +
4294 +        /**
4295 +         * Returns a task that when invoked, returns the result of
4296 +         * accumulating the given transformation of all (key, value) pairs
4297 +         * using the given reducer to combine values, and the given
4298 +         * basis as an identity value.
4299 +         *
4300 +         * @param transformer a function returning the transformation
4301 +         * for an element
4302 +         * @param basis the identity (initial default value) for the reduction
4303 +         * @param reducer a commutative associative combining function
4304 +         * @return the task
4305 +         */
4306 +        public static <K,V> ForkJoinTask<Integer> reduceToInt
4307 +            (ConcurrentHashMapV8<K,V> map,
4308 +             ObjectByObjectToInt<? super K, ? super V> transformer,
4309 +             int basis,
4310 +             IntByIntToInt reducer) {
4311 +            if (transformer == null || reducer == null)
4312 +                throw new NullPointerException();
4313 +            return new MapReduceMappingsToIntTask<K,V>
4314 +                (map, transformer, basis, reducer);
4315 +        }
4316 +
4317 +        /**
4318 +         * Returns a task that when invoked, performs the given action
4319 +         * for each key.
4320 +         *
4321 +         * @param map the map
4322 +         * @param action the action
4323 +         * @return the task
4324 +         */
4325 +        public static <K,V> ForkJoinTask<Void> forEachKey
4326 +            (ConcurrentHashMapV8<K,V> map,
4327 +             Action<K> action) {
4328 +            if (action == null) throw new NullPointerException();
4329 +            return new ForEachKeyTask<K,V>(map, action);
4330 +        }
4331 +
4332 +        /**
4333 +         * Returns a task that when invoked, performs the given action
4334 +         * for each non-null transformation of each key.
4335 +         *
4336 +         * @param map the map
4337 +         * @param transformer a function returning the transformation
4338 +         * for an element, or null of there is no transformation (in
4339 +         * which case the action is not applied).
4340 +         * @param action the action
4341 +         * @return the task
4342 +         */
4343 +        public static <K,V,U> ForkJoinTask<Void> forEachKey
4344 +            (ConcurrentHashMapV8<K,V> map,
4345 +             Fun<? super K, ? extends U> transformer,
4346 +             Action<U> action) {
4347 +            if (transformer == null || action == null)
4348 +                throw new NullPointerException();
4349 +            return new ForEachTransformedKeyTask<K,V,U>
4350 +                (map, transformer, action);
4351 +        }
4352 +
4353 +        /**
4354 +         * Returns a task that when invoked, returns a non-null result
4355 +         * from applying the given search function on each key, or
4356 +         * null if none.  Upon success, further element processing is
4357 +         * suppressed and the results of any other parallel
4358 +         * invocations of the search function are ignored.
4359 +         *
4360 +         * @param map the map
4361 +         * @param searchFunction a function returning a non-null
4362 +         * result on success, else null
4363 +         * @return the task
4364 +         */
4365 +        public static <K,V,U> ForkJoinTask<U> searchKeys
4366 +            (ConcurrentHashMapV8<K,V> map,
4367 +             Fun<? super K, ? extends U> searchFunction) {
4368 +            if (searchFunction == null) throw new NullPointerException();
4369 +            return new SearchKeysTask<K,V,U>
4370 +                (map, searchFunction,
4371 +                 new AtomicReference<U>());
4372 +        }
4373 +
4374 +        /**
4375 +         * Returns a task that when invoked, returns the result of
4376 +         * accumulating all keys using the given reducer to combine
4377 +         * values, or null if none.
4378 +         *
4379 +         * @param map the map
4380 +         * @param reducer a commutative associative combining function
4381 +         * @return the task
4382 +         */
4383 +        public static <K,V> ForkJoinTask<K> reduceKeys
4384 +            (ConcurrentHashMapV8<K,V> map,
4385 +             BiFun<? super K, ? super K, ? extends K> reducer) {
4386 +            if (reducer == null) throw new NullPointerException();
4387 +            return new ReduceKeysTask<K,V>
4388 +                (map, reducer);
4389 +        }
4390 +
4391 +        /**
4392 +         * Returns a task that when invoked, returns the result of
4393 +         * accumulating the given transformation of all keys using the given
4394 +         * reducer to combine values, or null if none.
4395 +         *
4396 +         * @param map the map
4397 +         * @param transformer a function returning the transformation
4398 +         * for an element, or null of there is no transformation (in
4399 +         * which case it is not combined).
4400 +         * @param reducer a commutative associative combining function
4401 +         * @return the task
4402 +         */
4403 +        public static <K,V,U> ForkJoinTask<U> reduceKeys
4404 +            (ConcurrentHashMapV8<K,V> map,
4405 +             Fun<? super K, ? extends U> transformer,
4406 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4407 +            if (transformer == null || reducer == null)
4408 +                throw new NullPointerException();
4409 +            return new MapReduceKeysTask<K,V,U>
4410 +                (map, transformer, reducer);
4411 +        }
4412 +
4413 +        /**
4414 +         * Returns a task that when invoked, returns the result of
4415 +         * accumulating the given transformation of all keys using the given
4416 +         * reducer to combine values, and the given basis as an
4417 +         * identity value.
4418 +         *
4419 +         * @param map the map
4420 +         * @param transformer a function returning the transformation
4421 +         * for an element
4422 +         * @param basis the identity (initial default value) for the reduction
4423 +         * @param reducer a commutative associative combining function
4424 +         * @return the task
4425 +         */
4426 +        public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
4427 +            (ConcurrentHashMapV8<K,V> map,
4428 +             ObjectToDouble<? super K> transformer,
4429 +             double basis,
4430 +             DoubleByDoubleToDouble reducer) {
4431 +            if (transformer == null || reducer == null)
4432 +                throw new NullPointerException();
4433 +            return new MapReduceKeysToDoubleTask<K,V>
4434 +                (map, transformer, basis, reducer);
4435 +        }
4436 +
4437 +        /**
4438 +         * Returns a task that when invoked, returns the result of
4439 +         * accumulating the given transformation of all keys using the given
4440 +         * reducer to combine values, and the given basis as an
4441 +         * identity value.
4442 +         *
4443 +         * @param map the map
4444 +         * @param transformer a function returning the transformation
4445 +         * for an element
4446 +         * @param basis the identity (initial default value) for the reduction
4447 +         * @param reducer a commutative associative combining function
4448 +         * @return the task
4449 +         */
4450 +        public static <K,V> ForkJoinTask<Long> reduceKeysToLong
4451 +            (ConcurrentHashMapV8<K,V> map,
4452 +             ObjectToLong<? super K> transformer,
4453 +             long basis,
4454 +             LongByLongToLong reducer) {
4455 +            if (transformer == null || reducer == null)
4456 +                throw new NullPointerException();
4457 +            return new MapReduceKeysToLongTask<K,V>
4458 +                (map, transformer, basis, reducer);
4459 +        }
4460 +
4461 +        /**
4462 +         * Returns a task that when invoked, returns the result of
4463 +         * accumulating the given transformation of all keys using the given
4464 +         * reducer to combine values, and the given basis as an
4465 +         * identity value.
4466 +         *
4467 +         * @param map the map
4468 +         * @param transformer a function returning the transformation
4469 +         * for an element
4470 +         * @param basis the identity (initial default value) for the reduction
4471 +         * @param reducer a commutative associative combining function
4472 +         * @return the task
4473 +         */
4474 +        public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
4475 +            (ConcurrentHashMapV8<K,V> map,
4476 +             ObjectToInt<? super K> transformer,
4477 +             int basis,
4478 +             IntByIntToInt reducer) {
4479 +            if (transformer == null || reducer == null)
4480 +                throw new NullPointerException();
4481 +            return new MapReduceKeysToIntTask<K,V>
4482 +                (map, transformer, basis, reducer);
4483 +        }
4484 +
4485 +        /**
4486 +         * Returns a task that when invoked, performs the given action
4487 +         * for each value.
4488 +         *
4489 +         * @param map the map
4490 +         * @param action the action
4491 +         */
4492 +        public static <K,V> ForkJoinTask<Void> forEachValue
4493 +            (ConcurrentHashMapV8<K,V> map,
4494 +             Action<V> action) {
4495 +            if (action == null) throw new NullPointerException();
4496 +            return new ForEachValueTask<K,V>(map, action);
4497 +        }
4498 +
4499 +        /**
4500 +         * Returns a task that when invoked, performs the given action
4501 +         * for each non-null transformation of each value.
4502 +         *
4503 +         * @param map the map
4504 +         * @param transformer a function returning the transformation
4505 +         * for an element, or null of there is no transformation (in
4506 +         * which case the action is not applied).
4507 +         * @param action the action
4508 +         */
4509 +        public static <K,V,U> ForkJoinTask<Void> forEachValue
4510 +            (ConcurrentHashMapV8<K,V> map,
4511 +             Fun<? super V, ? extends U> transformer,
4512 +             Action<U> action) {
4513 +            if (transformer == null || action == null)
4514 +                throw new NullPointerException();
4515 +            return new ForEachTransformedValueTask<K,V,U>
4516 +                (map, transformer, action);
4517 +        }
4518 +
4519 +        /**
4520 +         * Returns a task that when invoked, returns a non-null result
4521 +         * from applying the given search function on each value, or
4522 +         * null if none.  Upon success, further element processing is
4523 +         * suppressed and the results of any other parallel
4524 +         * invocations of the search function are ignored.
4525 +         *
4526 +         * @param map the map
4527 +         * @param searchFunction a function returning a non-null
4528 +         * result on success, else null
4529 +         * @return the task
4530 +         *
4531 +         */
4532 +        public static <K,V,U> ForkJoinTask<U> searchValues
4533 +            (ConcurrentHashMapV8<K,V> map,
4534 +             Fun<? super V, ? extends U> searchFunction) {
4535 +            if (searchFunction == null) throw new NullPointerException();
4536 +            return new SearchValuesTask<K,V,U>
4537 +                (map, searchFunction,
4538 +                 new AtomicReference<U>());
4539 +        }
4540 +
4541 +        /**
4542 +         * Returns a task that when invoked, returns the result of
4543 +         * accumulating all values using the given reducer to combine
4544 +         * values, or null if none.
4545 +         *
4546 +         * @param map the map
4547 +         * @param reducer a commutative associative combining function
4548 +         * @return the task
4549 +         */
4550 +        public static <K,V> ForkJoinTask<V> reduceValues
4551 +            (ConcurrentHashMapV8<K,V> map,
4552 +             BiFun<? super V, ? super V, ? extends V> reducer) {
4553 +            if (reducer == null) throw new NullPointerException();
4554 +            return new ReduceValuesTask<K,V>
4555 +                (map, reducer);
4556 +        }
4557 +
4558 +        /**
4559 +         * Returns a task that when invoked, returns the result of
4560 +         * accumulating the given transformation of all values using the
4561 +         * given reducer to combine values, or null if none.
4562 +         *
4563 +         * @param map the map
4564 +         * @param transformer a function returning the transformation
4565 +         * for an element, or null of there is no transformation (in
4566 +         * which case it is not combined).
4567 +         * @param reducer a commutative associative combining function
4568 +         * @return the task
4569 +         */
4570 +        public static <K,V,U> ForkJoinTask<U> reduceValues
4571 +            (ConcurrentHashMapV8<K,V> map,
4572 +             Fun<? super V, ? extends U> transformer,
4573 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4574 +            if (transformer == null || reducer == null)
4575 +                throw new NullPointerException();
4576 +            return new MapReduceValuesTask<K,V,U>
4577 +                (map, transformer, reducer);
4578 +        }
4579 +
4580 +        /**
4581 +         * Returns a task that when invoked, returns the result of
4582 +         * accumulating the given transformation of all values using the
4583 +         * given reducer to combine values, and the given basis as an
4584 +         * identity value.
4585 +         *
4586 +         * @param map the map
4587 +         * @param transformer a function returning the transformation
4588 +         * for an element
4589 +         * @param basis the identity (initial default value) for the reduction
4590 +         * @param reducer a commutative associative combining function
4591 +         * @return the task
4592 +         */
4593 +        public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
4594 +            (ConcurrentHashMapV8<K,V> map,
4595 +             ObjectToDouble<? super V> transformer,
4596 +             double basis,
4597 +             DoubleByDoubleToDouble reducer) {
4598 +            if (transformer == null || reducer == null)
4599 +                throw new NullPointerException();
4600 +            return new MapReduceValuesToDoubleTask<K,V>
4601 +                (map, transformer, basis, reducer);
4602 +        }
4603 +
4604 +        /**
4605 +         * Returns a task that when invoked, returns the result of
4606 +         * accumulating the given transformation of all values using the
4607 +         * given reducer to combine values, and the given basis as an
4608 +         * identity value.
4609 +         *
4610 +         * @param map the map
4611 +         * @param transformer a function returning the transformation
4612 +         * for an element
4613 +         * @param basis the identity (initial default value) for the reduction
4614 +         * @param reducer a commutative associative combining function
4615 +         * @return the task
4616 +         */
4617 +        public static <K,V> ForkJoinTask<Long> reduceValuesToLong
4618 +            (ConcurrentHashMapV8<K,V> map,
4619 +             ObjectToLong<? super V> transformer,
4620 +             long basis,
4621 +             LongByLongToLong reducer) {
4622 +            if (transformer == null || reducer == null)
4623 +                throw new NullPointerException();
4624 +            return new MapReduceValuesToLongTask<K,V>
4625 +                (map, transformer, basis, reducer);
4626 +        }
4627 +
4628 +        /**
4629 +         * Returns a task that when invoked, returns the result of
4630 +         * accumulating the given transformation of all values using the
4631 +         * given reducer to combine values, and the given basis as an
4632 +         * identity value.
4633 +         *
4634 +         * @param map the map
4635 +         * @param transformer a function returning the transformation
4636 +         * for an element
4637 +         * @param basis the identity (initial default value) for the reduction
4638 +         * @param reducer a commutative associative combining function
4639 +         * @return the task
4640 +         */
4641 +        public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
4642 +            (ConcurrentHashMapV8<K,V> map,
4643 +             ObjectToInt<? super V> transformer,
4644 +             int basis,
4645 +             IntByIntToInt reducer) {
4646 +            if (transformer == null || reducer == null)
4647 +                throw new NullPointerException();
4648 +            return new MapReduceValuesToIntTask<K,V>
4649 +                (map, transformer, basis, reducer);
4650 +        }
4651 +
4652 +        /**
4653 +         * Returns a task that when invoked, perform the given action
4654 +         * for each entry.
4655 +         *
4656 +         * @param map the map
4657 +         * @param action the action
4658 +         */
4659 +        public static <K,V> ForkJoinTask<Void> forEachEntry
4660 +            (ConcurrentHashMapV8<K,V> map,
4661 +             Action<Map.Entry<K,V>> action) {
4662 +            if (action == null) throw new NullPointerException();
4663 +            return new ForEachEntryTask<K,V>(map, action);
4664 +        }
4665 +
4666 +        /**
4667 +         * Returns a task that when invoked, perform the given action
4668 +         * for each non-null transformation of each entry.
4669 +         *
4670 +         * @param map the map
4671 +         * @param transformer a function returning the transformation
4672 +         * for an element, or null of there is no transformation (in
4673 +         * which case the action is not applied).
4674 +         * @param action the action
4675 +         */
4676 +        public static <K,V,U> ForkJoinTask<Void> forEachEntry
4677 +            (ConcurrentHashMapV8<K,V> map,
4678 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
4679 +             Action<U> action) {
4680 +            if (transformer == null || action == null)
4681 +                throw new NullPointerException();
4682 +            return new ForEachTransformedEntryTask<K,V,U>
4683 +                (map, transformer, action);
4684 +        }
4685 +
4686 +        /**
4687 +         * Returns a task that when invoked, returns a non-null result
4688 +         * from applying the given search function on each entry, or
4689 +         * null if none.  Upon success, further element processing is
4690 +         * suppressed and the results of any other parallel
4691 +         * invocations of the search function are ignored.
4692 +         *
4693 +         * @param map the map
4694 +         * @param searchFunction a function returning a non-null
4695 +         * result on success, else null
4696 +         * @return the task
4697 +         *
4698 +         */
4699 +        public static <K,V,U> ForkJoinTask<U> searchEntries
4700 +            (ConcurrentHashMapV8<K,V> map,
4701 +             Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4702 +            if (searchFunction == null) throw new NullPointerException();
4703 +            return new SearchEntriesTask<K,V,U>
4704 +                (map, searchFunction,
4705 +                 new AtomicReference<U>());
4706 +        }
4707 +
4708 +        /**
4709 +         * Returns a task that when invoked, returns the result of
4710 +         * accumulating all entries using the given reducer to combine
4711 +         * values, or null if none.
4712 +         *
4713 +         * @param map the map
4714 +         * @param reducer a commutative associative combining function
4715 +         * @return the task
4716 +         */
4717 +        public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
4718 +            (ConcurrentHashMapV8<K,V> map,
4719 +             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4720 +            if (reducer == null) throw new NullPointerException();
4721 +            return new ReduceEntriesTask<K,V>
4722 +                (map, reducer);
4723 +        }
4724 +
4725 +        /**
4726 +         * Returns a task that when invoked, returns the result of
4727 +         * accumulating the given transformation of all entries using the
4728 +         * given reducer to combine values, or null if none.
4729 +         *
4730 +         * @param map the map
4731 +         * @param transformer a function returning the transformation
4732 +         * for an element, or null of there is no transformation (in
4733 +         * which case it is not combined).
4734 +         * @param reducer a commutative associative combining function
4735 +         * @return the task
4736 +         */
4737 +        public static <K,V,U> ForkJoinTask<U> reduceEntries
4738 +            (ConcurrentHashMapV8<K,V> map,
4739 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
4740 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4741 +            if (transformer == null || reducer == null)
4742 +                throw new NullPointerException();
4743 +            return new MapReduceEntriesTask<K,V,U>
4744 +                (map, transformer, reducer);
4745 +        }
4746 +
4747 +        /**
4748 +         * Returns a task that when invoked, returns the result of
4749 +         * accumulating the given transformation of all entries using the
4750 +         * given reducer to combine values, and the given basis as an
4751 +         * identity value.
4752 +         *
4753 +         * @param map the map
4754 +         * @param transformer a function returning the transformation
4755 +         * for an element
4756 +         * @param basis the identity (initial default value) for the reduction
4757 +         * @param reducer a commutative associative combining function
4758 +         * @return the task
4759 +         */
4760 +        public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
4761 +            (ConcurrentHashMapV8<K,V> map,
4762 +             ObjectToDouble<Map.Entry<K,V>> transformer,
4763 +             double basis,
4764 +             DoubleByDoubleToDouble reducer) {
4765 +            if (transformer == null || reducer == null)
4766 +                throw new NullPointerException();
4767 +            return new MapReduceEntriesToDoubleTask<K,V>
4768 +                (map, transformer, basis, reducer);
4769 +        }
4770 +
4771 +        /**
4772 +         * Returns a task that when invoked, returns the result of
4773 +         * accumulating the given transformation of all entries using the
4774 +         * given reducer to combine values, and the given basis as an
4775 +         * identity value.
4776 +         *
4777 +         * @param map the map
4778 +         * @param transformer a function returning the transformation
4779 +         * for an element
4780 +         * @param basis the identity (initial default value) for the reduction
4781 +         * @param reducer a commutative associative combining function
4782 +         * @return the task
4783 +         */
4784 +        public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
4785 +            (ConcurrentHashMapV8<K,V> map,
4786 +             ObjectToLong<Map.Entry<K,V>> transformer,
4787 +             long basis,
4788 +             LongByLongToLong reducer) {
4789 +            if (transformer == null || reducer == null)
4790 +                throw new NullPointerException();
4791 +            return new MapReduceEntriesToLongTask<K,V>
4792 +                (map, transformer, basis, reducer);
4793 +        }
4794 +
4795 +        /**
4796 +         * Returns a task that when invoked, returns the result of
4797 +         * accumulating the given transformation of all entries using the
4798 +         * given reducer to combine values, and the given basis as an
4799 +         * identity value.
4800 +         *
4801 +         * @param map the map
4802 +         * @param transformer a function returning the transformation
4803 +         * for an element
4804 +         * @param basis the identity (initial default value) for the reduction
4805 +         * @param reducer a commutative associative combining function
4806 +         * @return the task
4807 +         */
4808 +        public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
4809 +            (ConcurrentHashMapV8<K,V> map,
4810 +             ObjectToInt<Map.Entry<K,V>> transformer,
4811 +             int basis,
4812 +             IntByIntToInt reducer) {
4813 +            if (transformer == null || reducer == null)
4814 +                throw new NullPointerException();
4815 +            return new MapReduceEntriesToIntTask<K,V>
4816 +                (map, transformer, basis, reducer);
4817 +        }
4818 +    }
4819 +
4820 +    // -------------------------------------------------------
4821 +
4822 +    /**
4823 +     * Base for FJ tasks for bulk operations. This adds a variant of
4824 +     * CountedCompleters and some split and merge bookkeeping to
4825 +     * iterator functionality. The forEach and reduce methods are
4826 +     * similar to those illustrated in CountedCompleter documentation,
4827 +     * except that bottom-up reduction completions perform them within
4828 +     * their compute methods. The search methods are like forEach
4829 +     * except they continually poll for success and exit early.  Also,
4830 +     * exceptions are handled in a simpler manner, by just trying to
4831 +     * complete root task exceptionally.
4832 +     */
4833 +    @SuppressWarnings("serial") static abstract class BulkTask<K,V,R> extends Traverser<K,V,R> {
4834 +        final BulkTask<K,V,?> parent;  // completion target
4835 +        int batch;                     // split control
4836 +        int pending;                   // completion control
4837 +
4838 +        /** Constructor for root tasks */
4839 +        BulkTask(ConcurrentHashMapV8<K,V> map) {
4840 +            super(map);
4841 +            this.parent = null;
4842 +            this.batch = -1; // force call to batch() on execution
4843 +        }
4844 +
4845 +        /** Constructor for subtasks */
4846 +        BulkTask(BulkTask<K,V,?> parent, int batch) {
4847 +            super(parent);
4848 +            this.parent = parent;
4849 +            this.batch = batch;
4850 +        }
4851 +
4852 +        // FJ methods
4853 +
4854 +        /**
4855 +         * Propagates completion. Note that all reduce actions
4856 +         * bypass this method to combine while completing.
4857 +         */
4858 +        final void tryComplete() {
4859 +            BulkTask<K,V,?> a = this, s = a;
4860 +            for (int c;;) {
4861 +                if ((c = a.pending) == 0) {
4862 +                    if ((a = (s = a).parent) == null) {
4863 +                        s.quietlyComplete();
4864 +                        break;
4865 +                    }
4866 +                }
4867 +                else if (U.compareAndSwapInt(a, PENDING, c, c - 1))
4868 +                    break;
4869 +            }
4870 +        }
4871 +
4872 +        /**
4873 +         * Forces root task to complete.
4874 +         * @param ex if null, complete normally, else exceptionally
4875 +         * @return false to simplify use
4876 +         */
4877 +        final boolean tryCompleteComputation(Throwable ex) {
4878 +            for (BulkTask<K,V,?> a = this;;) {
4879 +                BulkTask<K,V,?> p = a.parent;
4880 +                if (p == null) {
4881 +                    if (ex != null)
4882 +                        a.completeExceptionally(ex);
4883 +                    else
4884 +                        a.quietlyComplete();
4885 +                    return false;
4886 +                }
4887 +                a = p;
4888 +            }
4889 +        }
4890 +
4891 +        /**
4892 +         * Version of tryCompleteComputation for function screening checks
4893 +         */
4894 +        final boolean abortOnNullFunction() {
4895 +            return tryCompleteComputation(new Error("Unexpected null function"));
4896 +        }
4897 +
4898 +        // utilities
4899 +
4900 +        /** CompareAndSet pending count */
4901 +        final boolean casPending(int cmp, int val) {
4902 +            return U.compareAndSwapInt(this, PENDING, cmp, val);
4903 +        }
4904 +
4905 +        /**
4906 +         * Returns approx exp2 of the number of times (minus one) to
4907 +         * split task by two before executing leaf action. This value
4908 +         * is faster to compute and more convenient to use as a guide
4909 +         * to splitting than is the depth, since it is used while
4910 +         * dividing by two anyway.
4911 +         */
4912 +        final int batch() {
4913 +            int b = batch;
4914 +            if (b < 0) {
4915 +                long n = map.counter.sum();
4916 +                int sp = getPool().getParallelism() << 3; // slack of 8
4917 +                b = batch = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
4918 +            }
4919 +            return b;
4920 +        }
4921 +
4922 +        /**
4923 +         * Returns exportable snapshot entry.
4924 +         */
4925 +        static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
4926 +            return new AbstractMap.SimpleEntry<K,V>(k, v);
4927 +        }
4928 +
4929 +        // Unsafe mechanics
4930 +        private static final sun.misc.Unsafe U;
4931 +        private static final long PENDING;
4932 +        static {
4933 +            try {
4934 +                U = getUnsafe();
4935 +                PENDING = U.objectFieldOffset
4936 +                    (BulkTask.class.getDeclaredField("pending"));
4937 +            } catch (Exception e) {
4938 +                throw new Error(e);
4939 +            }
4940 +        }
4941 +    }
4942 +
4943 +    /*
4944 +     * Task classes. Coded in a regular but ugly format/style to
4945 +     * simplify checks that each variant differs in the right way from
4946 +     * others.
4947 +     */
4948 +
4949 +    @SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
4950 +        extends BulkTask<K,V,Void> {
4951 +        final Action<K> action;
4952 +        ForEachKeyTask
4953 +            (ConcurrentHashMapV8<K,V> m,
4954 +             Action<K> action) {
4955 +            super(m);
4956 +            this.action = action;
4957 +        }
4958 +        ForEachKeyTask
4959 +            (BulkTask<K,V,?> p, int b,
4960 +             Action<K> action) {
4961 +            super(p, b);
4962 +            this.action = action;
4963 +        }
4964 +        @SuppressWarnings("unchecked") public final boolean exec() {
4965 +            final Action<K> action = this.action;
4966 +            if (action == null)
4967 +                return abortOnNullFunction();
4968 +            try {
4969 +                int b = batch(), c;
4970 +                while (b > 1 && baseIndex != baseLimit) {
4971 +                    do {} while (!casPending(c = pending, c+1));
4972 +                    new ForEachKeyTask<K,V>(this, b >>>= 1, action).fork();
4973 +                }
4974 +                while (advance() != null)
4975 +                    action.apply((K)nextKey);
4976 +                tryComplete();
4977 +            } catch (Throwable ex) {
4978 +                return tryCompleteComputation(ex);
4979 +            }
4980 +            return false;
4981 +        }
4982 +    }
4983 +
4984 +    @SuppressWarnings("serial") static final class ForEachValueTask<K,V>
4985 +        extends BulkTask<K,V,Void> {
4986 +        final Action<V> action;
4987 +        ForEachValueTask
4988 +            (ConcurrentHashMapV8<K,V> m,
4989 +             Action<V> action) {
4990 +            super(m);
4991 +            this.action = action;
4992 +        }
4993 +        ForEachValueTask
4994 +            (BulkTask<K,V,?> p, int b,
4995 +             Action<V> action) {
4996 +            super(p, b);
4997 +            this.action = action;
4998 +        }
4999 +        @SuppressWarnings("unchecked") public final boolean exec() {
5000 +            final Action<V> action = this.action;
5001 +            if (action == null)
5002 +                return abortOnNullFunction();
5003 +            try {
5004 +                int b = batch(), c;
5005 +                while (b > 1 && baseIndex != baseLimit) {
5006 +                    do {} while (!casPending(c = pending, c+1));
5007 +                    new ForEachValueTask<K,V>(this, b >>>= 1, action).fork();
5008 +                }
5009 +                Object v;
5010 +                while ((v = advance()) != null)
5011 +                    action.apply((V)v);
5012 +                tryComplete();
5013 +            } catch (Throwable ex) {
5014 +                return tryCompleteComputation(ex);
5015 +            }
5016 +            return false;
5017 +        }
5018 +    }
5019 +
5020 +    @SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5021 +        extends BulkTask<K,V,Void> {
5022 +        final Action<Entry<K,V>> action;
5023 +        ForEachEntryTask
5024 +            (ConcurrentHashMapV8<K,V> m,
5025 +             Action<Entry<K,V>> action) {
5026 +            super(m);
5027 +            this.action = action;
5028 +        }
5029 +        ForEachEntryTask
5030 +            (BulkTask<K,V,?> p, int b,
5031 +             Action<Entry<K,V>> action) {
5032 +            super(p, b);
5033 +            this.action = action;
5034 +        }
5035 +        @SuppressWarnings("unchecked") public final boolean exec() {
5036 +            final Action<Entry<K,V>> action = this.action;
5037 +            if (action == null)
5038 +                return abortOnNullFunction();
5039 +            try {
5040 +                int b = batch(), c;
5041 +                while (b > 1 && baseIndex != baseLimit) {
5042 +                    do {} while (!casPending(c = pending, c+1));
5043 +                    new ForEachEntryTask<K,V>(this, b >>>= 1, action).fork();
5044 +                }
5045 +                Object v;
5046 +                while ((v = advance()) != null)
5047 +                    action.apply(entryFor((K)nextKey, (V)v));
5048 +                tryComplete();
5049 +            } catch (Throwable ex) {
5050 +                return tryCompleteComputation(ex);
5051 +            }
5052 +            return false;
5053 +        }
5054 +    }
5055 +
5056 +    @SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5057 +        extends BulkTask<K,V,Void> {
5058 +        final BiAction<K,V> action;
5059 +        ForEachMappingTask
5060 +            (ConcurrentHashMapV8<K,V> m,
5061 +             BiAction<K,V> action) {
5062 +            super(m);
5063 +            this.action = action;
5064 +        }
5065 +        ForEachMappingTask
5066 +            (BulkTask<K,V,?> p, int b,
5067 +             BiAction<K,V> action) {
5068 +            super(p, b);
5069 +            this.action = action;
5070 +        }
5071 +
5072 +        @SuppressWarnings("unchecked") public final boolean exec() {
5073 +            final BiAction<K,V> action = this.action;
5074 +            if (action == null)
5075 +                return abortOnNullFunction();
5076 +            try {
5077 +                int b = batch(), c;
5078 +                while (b > 1 && baseIndex != baseLimit) {
5079 +                    do {} while (!casPending(c = pending, c+1));
5080 +                    new ForEachMappingTask<K,V>(this, b >>>= 1,
5081 +                                                action).fork();
5082 +                }
5083 +                Object v;
5084 +                while ((v = advance()) != null)
5085 +                    action.apply((K)nextKey, (V)v);
5086 +                tryComplete();
5087 +            } catch (Throwable ex) {
5088 +                return tryCompleteComputation(ex);
5089 +            }
5090 +            return false;
5091 +        }
5092 +    }
5093 +
5094 +    @SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5095 +        extends BulkTask<K,V,Void> {
5096 +        final Fun<? super K, ? extends U> transformer;
5097 +        final Action<U> action;
5098 +        ForEachTransformedKeyTask
5099 +            (ConcurrentHashMapV8<K,V> m,
5100 +             Fun<? super K, ? extends U> transformer,
5101 +             Action<U> action) {
5102 +            super(m);
5103 +            this.transformer = transformer;
5104 +            this.action = action;
5105 +
5106 +        }
5107 +        ForEachTransformedKeyTask
5108 +            (BulkTask<K,V,?> p, int b,
5109 +             Fun<? super K, ? extends U> transformer,
5110 +             Action<U> action) {
5111 +            super(p, b);
5112 +            this.transformer = transformer;
5113 +            this.action = action;
5114 +        }
5115 +        @SuppressWarnings("unchecked") public final boolean exec() {
5116 +            final Fun<? super K, ? extends U> transformer =
5117 +                this.transformer;
5118 +            final Action<U> action = this.action;
5119 +            if (transformer == null || action == null)
5120 +                return abortOnNullFunction();
5121 +            try {
5122 +                int b = batch(), c;
5123 +                while (b > 1 && baseIndex != baseLimit) {
5124 +                    do {} while (!casPending(c = pending, c+1));
5125 +                    new ForEachTransformedKeyTask<K,V,U>
5126 +                        (this, b >>>= 1, transformer, action).fork();
5127 +                }
5128 +                U u;
5129 +                while (advance() != null) {
5130 +                    if ((u = transformer.apply((K)nextKey)) != null)
5131 +                        action.apply(u);
5132 +                }
5133 +                tryComplete();
5134 +            } catch (Throwable ex) {
5135 +                return tryCompleteComputation(ex);
5136 +            }
5137 +            return false;
5138 +        }
5139 +    }
5140 +
5141 +    @SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5142 +        extends BulkTask<K,V,Void> {
5143 +        final Fun<? super V, ? extends U> transformer;
5144 +        final Action<U> action;
5145 +        ForEachTransformedValueTask
5146 +            (ConcurrentHashMapV8<K,V> m,
5147 +             Fun<? super V, ? extends U> transformer,
5148 +             Action<U> action) {
5149 +            super(m);
5150 +            this.transformer = transformer;
5151 +            this.action = action;
5152 +
5153 +        }
5154 +        ForEachTransformedValueTask
5155 +            (BulkTask<K,V,?> p, int b,
5156 +             Fun<? super V, ? extends U> transformer,
5157 +             Action<U> action) {
5158 +            super(p, b);
5159 +            this.transformer = transformer;
5160 +            this.action = action;
5161 +        }
5162 +        @SuppressWarnings("unchecked") public final boolean exec() {
5163 +            final Fun<? super V, ? extends U> transformer =
5164 +                this.transformer;
5165 +            final Action<U> action = this.action;
5166 +            if (transformer == null || action == null)
5167 +                return abortOnNullFunction();
5168 +            try {
5169 +                int b = batch(), c;
5170 +                while (b > 1 && baseIndex != baseLimit) {
5171 +                    do {} while (!casPending(c = pending, c+1));
5172 +                    new ForEachTransformedValueTask<K,V,U>
5173 +                        (this, b >>>= 1, transformer, action).fork();
5174 +                }
5175 +                Object v; U u;
5176 +                while ((v = advance()) != null) {
5177 +                    if ((u = transformer.apply((V)v)) != null)
5178 +                        action.apply(u);
5179 +                }
5180 +                tryComplete();
5181 +            } catch (Throwable ex) {
5182 +                return tryCompleteComputation(ex);
5183 +            }
5184 +            return false;
5185 +        }
5186 +    }
5187 +
5188 +    @SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5189 +        extends BulkTask<K,V,Void> {
5190 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5191 +        final Action<U> action;
5192 +        ForEachTransformedEntryTask
5193 +            (ConcurrentHashMapV8<K,V> m,
5194 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5195 +             Action<U> action) {
5196 +            super(m);
5197 +            this.transformer = transformer;
5198 +            this.action = action;
5199 +
5200 +        }
5201 +        ForEachTransformedEntryTask
5202 +            (BulkTask<K,V,?> p, int b,
5203 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5204 +             Action<U> action) {
5205 +            super(p, b);
5206 +            this.transformer = transformer;
5207 +            this.action = action;
5208 +        }
5209 +        @SuppressWarnings("unchecked") public final boolean exec() {
5210 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5211 +                this.transformer;
5212 +            final Action<U> action = this.action;
5213 +            if (transformer == null || action == null)
5214 +                return abortOnNullFunction();
5215 +            try {
5216 +                int b = batch(), c;
5217 +                while (b > 1 && baseIndex != baseLimit) {
5218 +                    do {} while (!casPending(c = pending, c+1));
5219 +                    new ForEachTransformedEntryTask<K,V,U>
5220 +                        (this, b >>>= 1, transformer, action).fork();
5221 +                }
5222 +                Object v; U u;
5223 +                while ((v = advance()) != null) {
5224 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5225 +                        action.apply(u);
5226 +                }
5227 +                tryComplete();
5228 +            } catch (Throwable ex) {
5229 +                return tryCompleteComputation(ex);
5230 +            }
5231 +            return false;
5232 +        }
5233 +    }
5234 +
5235 +    @SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5236 +        extends BulkTask<K,V,Void> {
5237 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5238 +        final Action<U> action;
5239 +        ForEachTransformedMappingTask
5240 +            (ConcurrentHashMapV8<K,V> m,
5241 +             BiFun<? super K, ? super V, ? extends U> transformer,
5242 +             Action<U> action) {
5243 +            super(m);
5244 +            this.transformer = transformer;
5245 +            this.action = action;
5246 +
5247 +        }
5248 +        ForEachTransformedMappingTask
5249 +            (BulkTask<K,V,?> p, int b,
5250 +             BiFun<? super K, ? super V, ? extends U> transformer,
5251 +             Action<U> action) {
5252 +            super(p, b);
5253 +            this.transformer = transformer;
5254 +            this.action = action;
5255 +        }
5256 +        @SuppressWarnings("unchecked") public final boolean exec() {
5257 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5258 +                this.transformer;
5259 +            final Action<U> action = this.action;
5260 +            if (transformer == null || action == null)
5261 +                return abortOnNullFunction();
5262 +            try {
5263 +                int b = batch(), c;
5264 +                while (b > 1 && baseIndex != baseLimit) {
5265 +                    do {} while (!casPending(c = pending, c+1));
5266 +                    new ForEachTransformedMappingTask<K,V,U>
5267 +                        (this, b >>>= 1, transformer, action).fork();
5268 +                }
5269 +                Object v; U u;
5270 +                while ((v = advance()) != null) {
5271 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5272 +                        action.apply(u);
5273 +                }
5274 +                tryComplete();
5275 +            } catch (Throwable ex) {
5276 +                return tryCompleteComputation(ex);
5277 +            }
5278 +            return false;
5279 +        }
5280 +    }
5281 +
5282 +    @SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5283 +        extends BulkTask<K,V,U> {
5284 +        final Fun<? super K, ? extends U> searchFunction;
5285 +        final AtomicReference<U> result;
5286 +        SearchKeysTask
5287 +            (ConcurrentHashMapV8<K,V> m,
5288 +             Fun<? super K, ? extends U> searchFunction,
5289 +             AtomicReference<U> result) {
5290 +            super(m);
5291 +            this.searchFunction = searchFunction; this.result = result;
5292 +        }
5293 +        SearchKeysTask
5294 +            (BulkTask<K,V,?> p, int b,
5295 +             Fun<? super K, ? extends U> searchFunction,
5296 +             AtomicReference<U> result) {
5297 +            super(p, b);
5298 +            this.searchFunction = searchFunction; this.result = result;
5299 +        }
5300 +        @SuppressWarnings("unchecked") public final boolean exec() {
5301 +            AtomicReference<U> result = this.result;
5302 +            final Fun<? super K, ? extends U> searchFunction =
5303 +                this.searchFunction;
5304 +            if (searchFunction == null || result == null)
5305 +                return abortOnNullFunction();
5306 +            try {
5307 +                int b = batch(), c;
5308 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5309 +                    do {} while (!casPending(c = pending, c+1));
5310 +                    new SearchKeysTask<K,V,U>(this, b >>>= 1,
5311 +                                              searchFunction, result).fork();
5312 +                }
5313 +                U u;
5314 +                while (result.get() == null && advance() != null) {
5315 +                    if ((u = searchFunction.apply((K)nextKey)) != null) {
5316 +                        if (result.compareAndSet(null, u))
5317 +                            tryCompleteComputation(null);
5318 +                        break;
5319 +                    }
5320 +                }
5321 +                tryComplete();
5322 +            } catch (Throwable ex) {
5323 +                return tryCompleteComputation(ex);
5324 +            }
5325 +            return false;
5326 +        }
5327 +        public final U getRawResult() { return result.get(); }
5328 +    }
5329 +
5330 +    @SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5331 +        extends BulkTask<K,V,U> {
5332 +        final Fun<? super V, ? extends U> searchFunction;
5333 +        final AtomicReference<U> result;
5334 +        SearchValuesTask
5335 +            (ConcurrentHashMapV8<K,V> m,
5336 +             Fun<? super V, ? extends U> searchFunction,
5337 +             AtomicReference<U> result) {
5338 +            super(m);
5339 +            this.searchFunction = searchFunction; this.result = result;
5340 +        }
5341 +        SearchValuesTask
5342 +            (BulkTask<K,V,?> p, int b,
5343 +             Fun<? super V, ? extends U> searchFunction,
5344 +             AtomicReference<U> result) {
5345 +            super(p, b);
5346 +            this.searchFunction = searchFunction; this.result = result;
5347 +        }
5348 +        @SuppressWarnings("unchecked") public final boolean exec() {
5349 +            AtomicReference<U> result = this.result;
5350 +            final Fun<? super V, ? extends U> searchFunction =
5351 +                this.searchFunction;
5352 +            if (searchFunction == null || result == null)
5353 +                return abortOnNullFunction();
5354 +            try {
5355 +                int b = batch(), c;
5356 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5357 +                    do {} while (!casPending(c = pending, c+1));
5358 +                    new SearchValuesTask<K,V,U>(this, b >>>= 1,
5359 +                                                searchFunction, result).fork();
5360 +                }
5361 +                Object v; U u;
5362 +                while (result.get() == null && (v = advance()) != null) {
5363 +                    if ((u = searchFunction.apply((V)v)) != null) {
5364 +                        if (result.compareAndSet(null, u))
5365 +                            tryCompleteComputation(null);
5366 +                        break;
5367 +                    }
5368 +                }
5369 +                tryComplete();
5370 +            } catch (Throwable ex) {
5371 +                return tryCompleteComputation(ex);
5372 +            }
5373 +            return false;
5374 +        }
5375 +        public final U getRawResult() { return result.get(); }
5376 +    }
5377 +
5378 +    @SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5379 +        extends BulkTask<K,V,U> {
5380 +        final Fun<Entry<K,V>, ? extends U> searchFunction;
5381 +        final AtomicReference<U> result;
5382 +        SearchEntriesTask
5383 +            (ConcurrentHashMapV8<K,V> m,
5384 +             Fun<Entry<K,V>, ? extends U> searchFunction,
5385 +             AtomicReference<U> result) {
5386 +            super(m);
5387 +            this.searchFunction = searchFunction; this.result = result;
5388 +        }
5389 +        SearchEntriesTask
5390 +            (BulkTask<K,V,?> p, int b,
5391 +             Fun<Entry<K,V>, ? extends U> searchFunction,
5392 +             AtomicReference<U> result) {
5393 +            super(p, b);
5394 +            this.searchFunction = searchFunction; this.result = result;
5395 +        }
5396 +        @SuppressWarnings("unchecked") public final boolean exec() {
5397 +            AtomicReference<U> result = this.result;
5398 +            final Fun<Entry<K,V>, ? extends U> searchFunction =
5399 +                this.searchFunction;
5400 +            if (searchFunction == null || result == null)
5401 +                return abortOnNullFunction();
5402 +            try {
5403 +                int b = batch(), c;
5404 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5405 +                    do {} while (!casPending(c = pending, c+1));
5406 +                    new SearchEntriesTask<K,V,U>(this, b >>>= 1,
5407 +                                                 searchFunction, result).fork();
5408 +                }
5409 +                Object v; U u;
5410 +                while (result.get() == null && (v = advance()) != null) {
5411 +                    if ((u = searchFunction.apply(entryFor((K)nextKey, (V)v))) != null) {
5412 +                        if (result.compareAndSet(null, u))
5413 +                            tryCompleteComputation(null);
5414 +                        break;
5415 +                    }
5416 +                }
5417 +                tryComplete();
5418 +            } catch (Throwable ex) {
5419 +                return tryCompleteComputation(ex);
5420 +            }
5421 +            return false;
5422 +        }
5423 +        public final U getRawResult() { return result.get(); }
5424 +    }
5425 +
5426 +    @SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5427 +        extends BulkTask<K,V,U> {
5428 +        final BiFun<? super K, ? super V, ? extends U> searchFunction;
5429 +        final AtomicReference<U> result;
5430 +        SearchMappingsTask
5431 +            (ConcurrentHashMapV8<K,V> m,
5432 +             BiFun<? super K, ? super V, ? extends U> searchFunction,
5433 +             AtomicReference<U> result) {
5434 +            super(m);
5435 +            this.searchFunction = searchFunction; this.result = result;
5436 +        }
5437 +        SearchMappingsTask
5438 +            (BulkTask<K,V,?> p, int b,
5439 +             BiFun<? super K, ? super V, ? extends U> searchFunction,
5440 +             AtomicReference<U> result) {
5441 +            super(p, b);
5442 +            this.searchFunction = searchFunction; this.result = result;
5443 +        }
5444 +        @SuppressWarnings("unchecked") public final boolean exec() {
5445 +            AtomicReference<U> result = this.result;
5446 +            final BiFun<? super K, ? super V, ? extends U> searchFunction =
5447 +                this.searchFunction;
5448 +            if (searchFunction == null || result == null)
5449 +                return abortOnNullFunction();
5450 +            try {
5451 +                int b = batch(), c;
5452 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5453 +                    do {} while (!casPending(c = pending, c+1));
5454 +                    new SearchMappingsTask<K,V,U>(this, b >>>= 1,
5455 +                                                  searchFunction, result).fork();
5456 +                }
5457 +                Object v; U u;
5458 +                while (result.get() == null && (v = advance()) != null) {
5459 +                    if ((u = searchFunction.apply((K)nextKey, (V)v)) != null) {
5460 +                        if (result.compareAndSet(null, u))
5461 +                            tryCompleteComputation(null);
5462 +                        break;
5463 +                    }
5464 +                }
5465 +                tryComplete();
5466 +            } catch (Throwable ex) {
5467 +                return tryCompleteComputation(ex);
5468 +            }
5469 +            return false;
5470 +        }
5471 +        public final U getRawResult() { return result.get(); }
5472 +    }
5473 +
5474 +    @SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5475 +        extends BulkTask<K,V,K> {
5476 +        final BiFun<? super K, ? super K, ? extends K> reducer;
5477 +        K result;
5478 +        ReduceKeysTask<K,V> rights, nextRight;
5479 +        ReduceKeysTask
5480 +            (ConcurrentHashMapV8<K,V> m,
5481 +             BiFun<? super K, ? super K, ? extends K> reducer) {
5482 +            super(m);
5483 +            this.reducer = reducer;
5484 +        }
5485 +        ReduceKeysTask
5486 +            (BulkTask<K,V,?> p, int b,
5487 +             ReduceKeysTask<K,V> nextRight,
5488 +             BiFun<? super K, ? super K, ? extends K> reducer) {
5489 +            super(p, b); this.nextRight = nextRight;
5490 +            this.reducer = reducer;
5491 +        }
5492 +
5493 +        @SuppressWarnings("unchecked") public final boolean exec() {
5494 +            final BiFun<? super K, ? super K, ? extends K> reducer =
5495 +                this.reducer;
5496 +            if (reducer == null)
5497 +                return abortOnNullFunction();
5498 +            try {
5499 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5500 +                    do {} while (!casPending(c = pending, c+1));
5501 +                    (rights = new ReduceKeysTask<K,V>
5502 +                     (this, b >>>= 1, rights, reducer)).fork();
5503 +                }
5504 +                K r = null;
5505 +                while (advance() != null) {
5506 +                    K u = (K)nextKey;
5507 +                    r = (r == null) ? u : reducer.apply(r, u);
5508 +                }
5509 +                result = r;
5510 +                for (ReduceKeysTask<K,V> t = this, s;;) {
5511 +                    int c; BulkTask<K,V,?> par; K tr, sr;
5512 +                    if ((c = t.pending) == 0) {
5513 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5514 +                            if ((sr = s.result) != null)
5515 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5516 +                        }
5517 +                        if ((par = t.parent) == null ||
5518 +                            !(par instanceof ReduceKeysTask)) {
5519 +                            t.quietlyComplete();
5520 +                            break;
5521 +                        }
5522 +                        t = (ReduceKeysTask<K,V>)par;
5523 +                    }
5524 +                    else if (t.casPending(c, c - 1))
5525 +                        break;
5526 +                }
5527 +            } catch (Throwable ex) {
5528 +                return tryCompleteComputation(ex);
5529 +            }
5530 +            return false;
5531 +        }
5532 +        public final K getRawResult() { return result; }
5533 +    }
5534 +
5535 +    @SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5536 +        extends BulkTask<K,V,V> {
5537 +        final BiFun<? super V, ? super V, ? extends V> reducer;
5538 +        V result;
5539 +        ReduceValuesTask<K,V> rights, nextRight;
5540 +        ReduceValuesTask
5541 +            (ConcurrentHashMapV8<K,V> m,
5542 +             BiFun<? super V, ? super V, ? extends V> reducer) {
5543 +            super(m);
5544 +            this.reducer = reducer;
5545 +        }
5546 +        ReduceValuesTask
5547 +            (BulkTask<K,V,?> p, int b,
5548 +             ReduceValuesTask<K,V> nextRight,
5549 +             BiFun<? super V, ? super V, ? extends V> reducer) {
5550 +            super(p, b); this.nextRight = nextRight;
5551 +            this.reducer = reducer;
5552 +        }
5553 +
5554 +        @SuppressWarnings("unchecked") public final boolean exec() {
5555 +            final BiFun<? super V, ? super V, ? extends V> reducer =
5556 +                this.reducer;
5557 +            if (reducer == null)
5558 +                return abortOnNullFunction();
5559 +            try {
5560 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5561 +                    do {} while (!casPending(c = pending, c+1));
5562 +                    (rights = new ReduceValuesTask<K,V>
5563 +                     (this, b >>>= 1, rights, reducer)).fork();
5564 +                }
5565 +                V r = null;
5566 +                Object v;
5567 +                while ((v = advance()) != null) {
5568 +                    V u = (V)v;
5569 +                    r = (r == null) ? u : reducer.apply(r, u);
5570 +                }
5571 +                result = r;
5572 +                for (ReduceValuesTask<K,V> t = this, s;;) {
5573 +                    int c; BulkTask<K,V,?> par; V tr, sr;
5574 +                    if ((c = t.pending) == 0) {
5575 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5576 +                            if ((sr = s.result) != null)
5577 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5578 +                        }
5579 +                        if ((par = t.parent) == null ||
5580 +                            !(par instanceof ReduceValuesTask)) {
5581 +                            t.quietlyComplete();
5582 +                            break;
5583 +                        }
5584 +                        t = (ReduceValuesTask<K,V>)par;
5585 +                    }
5586 +                    else if (t.casPending(c, c - 1))
5587 +                        break;
5588 +                }
5589 +            } catch (Throwable ex) {
5590 +                return tryCompleteComputation(ex);
5591 +            }
5592 +            return false;
5593 +        }
5594 +        public final V getRawResult() { return result; }
5595 +    }
5596 +
5597 +    @SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
5598 +        extends BulkTask<K,V,Map.Entry<K,V>> {
5599 +        final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5600 +        Map.Entry<K,V> result;
5601 +        ReduceEntriesTask<K,V> rights, nextRight;
5602 +        ReduceEntriesTask
5603 +            (ConcurrentHashMapV8<K,V> m,
5604 +             BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5605 +            super(m);
5606 +            this.reducer = reducer;
5607 +        }
5608 +        ReduceEntriesTask
5609 +            (BulkTask<K,V,?> p, int b,
5610 +             ReduceEntriesTask<K,V> nextRight,
5611 +             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5612 +            super(p, b); this.nextRight = nextRight;
5613 +            this.reducer = reducer;
5614 +        }
5615 +
5616 +        @SuppressWarnings("unchecked") public final boolean exec() {
5617 +            final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer =
5618 +                this.reducer;
5619 +            if (reducer == null)
5620 +                return abortOnNullFunction();
5621 +            try {
5622 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5623 +                    do {} while (!casPending(c = pending, c+1));
5624 +                    (rights = new ReduceEntriesTask<K,V>
5625 +                     (this, b >>>= 1, rights, reducer)).fork();
5626 +                }
5627 +                Map.Entry<K,V> r = null;
5628 +                Object v;
5629 +                while ((v = advance()) != null) {
5630 +                    Map.Entry<K,V> u = entryFor((K)nextKey, (V)v);
5631 +                    r = (r == null) ? u : reducer.apply(r, u);
5632 +                }
5633 +                result = r;
5634 +                for (ReduceEntriesTask<K,V> t = this, s;;) {
5635 +                    int c; BulkTask<K,V,?> par; Map.Entry<K,V> tr, sr;
5636 +                    if ((c = t.pending) == 0) {
5637 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5638 +                            if ((sr = s.result) != null)
5639 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5640 +                        }
5641 +                        if ((par = t.parent) == null ||
5642 +                            !(par instanceof ReduceEntriesTask)) {
5643 +                            t.quietlyComplete();
5644 +                            break;
5645 +                        }
5646 +                        t = (ReduceEntriesTask<K,V>)par;
5647 +                    }
5648 +                    else if (t.casPending(c, c - 1))
5649 +                        break;
5650 +                }
5651 +            } catch (Throwable ex) {
5652 +                return tryCompleteComputation(ex);
5653 +            }
5654 +            return false;
5655 +        }
5656 +        public final Map.Entry<K,V> getRawResult() { return result; }
5657 +    }
5658 +
5659 +    @SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
5660 +        extends BulkTask<K,V,U> {
5661 +        final Fun<? super K, ? extends U> transformer;
5662 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5663 +        U result;
5664 +        MapReduceKeysTask<K,V,U> rights, nextRight;
5665 +        MapReduceKeysTask
5666 +            (ConcurrentHashMapV8<K,V> m,
5667 +             Fun<? super K, ? extends U> transformer,
5668 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5669 +            super(m);
5670 +            this.transformer = transformer;
5671 +            this.reducer = reducer;
5672 +        }
5673 +        MapReduceKeysTask
5674 +            (BulkTask<K,V,?> p, int b,
5675 +             MapReduceKeysTask<K,V,U> nextRight,
5676 +             Fun<? super K, ? extends U> transformer,
5677 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5678 +            super(p, b); this.nextRight = nextRight;
5679 +            this.transformer = transformer;
5680 +            this.reducer = reducer;
5681 +        }
5682 +        @SuppressWarnings("unchecked") public final boolean exec() {
5683 +            final Fun<? super K, ? extends U> transformer =
5684 +                this.transformer;
5685 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5686 +                this.reducer;
5687 +            if (transformer == null || reducer == null)
5688 +                return abortOnNullFunction();
5689 +            try {
5690 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5691 +                    do {} while (!casPending(c = pending, c+1));
5692 +                    (rights = new MapReduceKeysTask<K,V,U>
5693 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5694 +                }
5695 +                U r = null, u;
5696 +                while (advance() != null) {
5697 +                    if ((u = transformer.apply((K)nextKey)) != null)
5698 +                        r = (r == null) ? u : reducer.apply(r, u);
5699 +                }
5700 +                result = r;
5701 +                for (MapReduceKeysTask<K,V,U> t = this, s;;) {
5702 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5703 +                    if ((c = t.pending) == 0) {
5704 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5705 +                            if ((sr = s.result) != null)
5706 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5707 +                        }
5708 +                        if ((par = t.parent) == null ||
5709 +                            !(par instanceof MapReduceKeysTask)) {
5710 +                            t.quietlyComplete();
5711 +                            break;
5712 +                        }
5713 +                        t = (MapReduceKeysTask<K,V,U>)par;
5714 +                    }
5715 +                    else if (t.casPending(c, c - 1))
5716 +                        break;
5717 +                }
5718 +            } catch (Throwable ex) {
5719 +                return tryCompleteComputation(ex);
5720 +            }
5721 +            return false;
5722 +        }
5723 +        public final U getRawResult() { return result; }
5724 +    }
5725 +
5726 +    @SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
5727 +        extends BulkTask<K,V,U> {
5728 +        final Fun<? super V, ? extends U> transformer;
5729 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5730 +        U result;
5731 +        MapReduceValuesTask<K,V,U> rights, nextRight;
5732 +        MapReduceValuesTask
5733 +            (ConcurrentHashMapV8<K,V> m,
5734 +             Fun<? super V, ? extends U> transformer,
5735 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5736 +            super(m);
5737 +            this.transformer = transformer;
5738 +            this.reducer = reducer;
5739 +        }
5740 +        MapReduceValuesTask
5741 +            (BulkTask<K,V,?> p, int b,
5742 +             MapReduceValuesTask<K,V,U> nextRight,
5743 +             Fun<? super V, ? extends U> transformer,
5744 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5745 +            super(p, b); this.nextRight = nextRight;
5746 +            this.transformer = transformer;
5747 +            this.reducer = reducer;
5748 +        }
5749 +        @SuppressWarnings("unchecked") public final boolean exec() {
5750 +            final Fun<? super V, ? extends U> transformer =
5751 +                this.transformer;
5752 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5753 +                this.reducer;
5754 +            if (transformer == null || reducer == null)
5755 +                return abortOnNullFunction();
5756 +            try {
5757 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5758 +                    do {} while (!casPending(c = pending, c+1));
5759 +                    (rights = new MapReduceValuesTask<K,V,U>
5760 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5761 +                }
5762 +                U r = null, u;
5763 +                Object v;
5764 +                while ((v = advance()) != null) {
5765 +                    if ((u = transformer.apply((V)v)) != null)
5766 +                        r = (r == null) ? u : reducer.apply(r, u);
5767 +                }
5768 +                result = r;
5769 +                for (MapReduceValuesTask<K,V,U> t = this, s;;) {
5770 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5771 +                    if ((c = t.pending) == 0) {
5772 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5773 +                            if ((sr = s.result) != null)
5774 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5775 +                        }
5776 +                        if ((par = t.parent) == null ||
5777 +                            !(par instanceof MapReduceValuesTask)) {
5778 +                            t.quietlyComplete();
5779 +                            break;
5780 +                        }
5781 +                        t = (MapReduceValuesTask<K,V,U>)par;
5782 +                    }
5783 +                    else if (t.casPending(c, c - 1))
5784 +                        break;
5785 +                }
5786 +            } catch (Throwable ex) {
5787 +                return tryCompleteComputation(ex);
5788 +            }
5789 +            return false;
5790 +        }
5791 +        public final U getRawResult() { return result; }
5792 +    }
5793 +
5794 +    @SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
5795 +        extends BulkTask<K,V,U> {
5796 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5797 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5798 +        U result;
5799 +        MapReduceEntriesTask<K,V,U> rights, nextRight;
5800 +        MapReduceEntriesTask
5801 +            (ConcurrentHashMapV8<K,V> m,
5802 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5803 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5804 +            super(m);
5805 +            this.transformer = transformer;
5806 +            this.reducer = reducer;
5807 +        }
5808 +        MapReduceEntriesTask
5809 +            (BulkTask<K,V,?> p, int b,
5810 +             MapReduceEntriesTask<K,V,U> nextRight,
5811 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5812 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5813 +            super(p, b); this.nextRight = nextRight;
5814 +            this.transformer = transformer;
5815 +            this.reducer = reducer;
5816 +        }
5817 +        @SuppressWarnings("unchecked") public final boolean exec() {
5818 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5819 +                this.transformer;
5820 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5821 +                this.reducer;
5822 +            if (transformer == null || reducer == null)
5823 +                return abortOnNullFunction();
5824 +            try {
5825 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5826 +                    do {} while (!casPending(c = pending, c+1));
5827 +                    (rights = new MapReduceEntriesTask<K,V,U>
5828 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5829 +                }
5830 +                U r = null, u;
5831 +                Object v;
5832 +                while ((v = advance()) != null) {
5833 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5834 +                        r = (r == null) ? u : reducer.apply(r, u);
5835 +                }
5836 +                result = r;
5837 +                for (MapReduceEntriesTask<K,V,U> t = this, s;;) {
5838 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5839 +                    if ((c = t.pending) == 0) {
5840 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5841 +                            if ((sr = s.result) != null)
5842 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5843 +                        }
5844 +                        if ((par = t.parent) == null ||
5845 +                            !(par instanceof MapReduceEntriesTask)) {
5846 +                            t.quietlyComplete();
5847 +                            break;
5848 +                        }
5849 +                        t = (MapReduceEntriesTask<K,V,U>)par;
5850 +                    }
5851 +                    else if (t.casPending(c, c - 1))
5852 +                        break;
5853 +                }
5854 +            } catch (Throwable ex) {
5855 +                return tryCompleteComputation(ex);
5856 +            }
5857 +            return false;
5858 +        }
5859 +        public final U getRawResult() { return result; }
5860 +    }
5861 +
5862 +    @SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
5863 +        extends BulkTask<K,V,U> {
5864 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5865 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5866 +        U result;
5867 +        MapReduceMappingsTask<K,V,U> rights, nextRight;
5868 +        MapReduceMappingsTask
5869 +            (ConcurrentHashMapV8<K,V> m,
5870 +             BiFun<? super K, ? super V, ? extends U> transformer,
5871 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5872 +            super(m);
5873 +            this.transformer = transformer;
5874 +            this.reducer = reducer;
5875 +        }
5876 +        MapReduceMappingsTask
5877 +            (BulkTask<K,V,?> p, int b,
5878 +             MapReduceMappingsTask<K,V,U> nextRight,
5879 +             BiFun<? super K, ? super V, ? extends U> transformer,
5880 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5881 +            super(p, b); this.nextRight = nextRight;
5882 +            this.transformer = transformer;
5883 +            this.reducer = reducer;
5884 +        }
5885 +        @SuppressWarnings("unchecked") public final boolean exec() {
5886 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5887 +                this.transformer;
5888 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5889 +                this.reducer;
5890 +            if (transformer == null || reducer == null)
5891 +                return abortOnNullFunction();
5892 +            try {
5893 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5894 +                    do {} while (!casPending(c = pending, c+1));
5895 +                    (rights = new MapReduceMappingsTask<K,V,U>
5896 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5897 +                }
5898 +                U r = null, u;
5899 +                Object v;
5900 +                while ((v = advance()) != null) {
5901 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5902 +                        r = (r == null) ? u : reducer.apply(r, u);
5903 +                }
5904 +                result = r;
5905 +                for (MapReduceMappingsTask<K,V,U> t = this, s;;) {
5906 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5907 +                    if ((c = t.pending) == 0) {
5908 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5909 +                            if ((sr = s.result) != null)
5910 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5911 +                        }
5912 +                        if ((par = t.parent) == null ||
5913 +                            !(par instanceof MapReduceMappingsTask)) {
5914 +                            t.quietlyComplete();
5915 +                            break;
5916 +                        }
5917 +                        t = (MapReduceMappingsTask<K,V,U>)par;
5918 +                    }
5919 +                    else if (t.casPending(c, c - 1))
5920 +                        break;
5921 +                }
5922 +            } catch (Throwable ex) {
5923 +                return tryCompleteComputation(ex);
5924 +            }
5925 +            return false;
5926 +        }
5927 +        public final U getRawResult() { return result; }
5928 +    }
5929 +
5930 +    @SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
5931 +        extends BulkTask<K,V,Double> {
5932 +        final ObjectToDouble<? super K> transformer;
5933 +        final DoubleByDoubleToDouble reducer;
5934 +        final double basis;
5935 +        double result;
5936 +        MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5937 +        MapReduceKeysToDoubleTask
5938 +            (ConcurrentHashMapV8<K,V> m,
5939 +             ObjectToDouble<? super K> transformer,
5940 +             double basis,
5941 +             DoubleByDoubleToDouble reducer) {
5942 +            super(m);
5943 +            this.transformer = transformer;
5944 +            this.basis = basis; this.reducer = reducer;
5945 +        }
5946 +        MapReduceKeysToDoubleTask
5947 +            (BulkTask<K,V,?> p, int b,
5948 +             MapReduceKeysToDoubleTask<K,V> nextRight,
5949 +             ObjectToDouble<? super K> transformer,
5950 +             double basis,
5951 +             DoubleByDoubleToDouble reducer) {
5952 +            super(p, b); this.nextRight = nextRight;
5953 +            this.transformer = transformer;
5954 +            this.basis = basis; this.reducer = reducer;
5955 +        }
5956 +        @SuppressWarnings("unchecked") public final boolean exec() {
5957 +            final ObjectToDouble<? super K> transformer =
5958 +                this.transformer;
5959 +            final DoubleByDoubleToDouble reducer = this.reducer;
5960 +            if (transformer == null || reducer == null)
5961 +                return abortOnNullFunction();
5962 +            try {
5963 +                final double id = this.basis;
5964 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5965 +                    do {} while (!casPending(c = pending, c+1));
5966 +                    (rights = new MapReduceKeysToDoubleTask<K,V>
5967 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5968 +                }
5969 +                double r = id;
5970 +                while (advance() != null)
5971 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
5972 +                result = r;
5973 +                for (MapReduceKeysToDoubleTask<K,V> t = this, s;;) {
5974 +                    int c; BulkTask<K,V,?> par;
5975 +                    if ((c = t.pending) == 0) {
5976 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5977 +                            t.result = reducer.apply(t.result, s.result);
5978 +                        }
5979 +                        if ((par = t.parent) == null ||
5980 +                            !(par instanceof MapReduceKeysToDoubleTask)) {
5981 +                            t.quietlyComplete();
5982 +                            break;
5983 +                        }
5984 +                        t = (MapReduceKeysToDoubleTask<K,V>)par;
5985 +                    }
5986 +                    else if (t.casPending(c, c - 1))
5987 +                        break;
5988 +                }
5989 +            } catch (Throwable ex) {
5990 +                return tryCompleteComputation(ex);
5991 +            }
5992 +            return false;
5993 +        }
5994 +        public final Double getRawResult() { return result; }
5995 +    }
5996 +
5997 +    @SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
5998 +        extends BulkTask<K,V,Double> {
5999 +        final ObjectToDouble<? super V> transformer;
6000 +        final DoubleByDoubleToDouble reducer;
6001 +        final double basis;
6002 +        double result;
6003 +        MapReduceValuesToDoubleTask<K,V> rights, nextRight;
6004 +        MapReduceValuesToDoubleTask
6005 +            (ConcurrentHashMapV8<K,V> m,
6006 +             ObjectToDouble<? super V> transformer,
6007 +             double basis,
6008 +             DoubleByDoubleToDouble reducer) {
6009 +            super(m);
6010 +            this.transformer = transformer;
6011 +            this.basis = basis; this.reducer = reducer;
6012 +        }
6013 +        MapReduceValuesToDoubleTask
6014 +            (BulkTask<K,V,?> p, int b,
6015 +             MapReduceValuesToDoubleTask<K,V> nextRight,
6016 +             ObjectToDouble<? super V> transformer,
6017 +             double basis,
6018 +             DoubleByDoubleToDouble reducer) {
6019 +            super(p, b); this.nextRight = nextRight;
6020 +            this.transformer = transformer;
6021 +            this.basis = basis; this.reducer = reducer;
6022 +        }
6023 +        @SuppressWarnings("unchecked") public final boolean exec() {
6024 +            final ObjectToDouble<? super V> transformer =
6025 +                this.transformer;
6026 +            final DoubleByDoubleToDouble reducer = this.reducer;
6027 +            if (transformer == null || reducer == null)
6028 +                return abortOnNullFunction();
6029 +            try {
6030 +                final double id = this.basis;
6031 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6032 +                    do {} while (!casPending(c = pending, c+1));
6033 +                    (rights = new MapReduceValuesToDoubleTask<K,V>
6034 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6035 +                }
6036 +                double r = id;
6037 +                Object v;
6038 +                while ((v = advance()) != null)
6039 +                    r = reducer.apply(r, transformer.apply((V)v));
6040 +                result = r;
6041 +                for (MapReduceValuesToDoubleTask<K,V> t = this, s;;) {
6042 +                    int c; BulkTask<K,V,?> par;
6043 +                    if ((c = t.pending) == 0) {
6044 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6045 +                            t.result = reducer.apply(t.result, s.result);
6046 +                        }
6047 +                        if ((par = t.parent) == null ||
6048 +                            !(par instanceof MapReduceValuesToDoubleTask)) {
6049 +                            t.quietlyComplete();
6050 +                            break;
6051 +                        }
6052 +                        t = (MapReduceValuesToDoubleTask<K,V>)par;
6053 +                    }
6054 +                    else if (t.casPending(c, c - 1))
6055 +                        break;
6056 +                }
6057 +            } catch (Throwable ex) {
6058 +                return tryCompleteComputation(ex);
6059 +            }
6060 +            return false;
6061 +        }
6062 +        public final Double getRawResult() { return result; }
6063 +    }
6064 +
6065 +    @SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6066 +        extends BulkTask<K,V,Double> {
6067 +        final ObjectToDouble<Map.Entry<K,V>> transformer;
6068 +        final DoubleByDoubleToDouble reducer;
6069 +        final double basis;
6070 +        double result;
6071 +        MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6072 +        MapReduceEntriesToDoubleTask
6073 +            (ConcurrentHashMapV8<K,V> m,
6074 +             ObjectToDouble<Map.Entry<K,V>> transformer,
6075 +             double basis,
6076 +             DoubleByDoubleToDouble reducer) {
6077 +            super(m);
6078 +            this.transformer = transformer;
6079 +            this.basis = basis; this.reducer = reducer;
6080 +        }
6081 +        MapReduceEntriesToDoubleTask
6082 +            (BulkTask<K,V,?> p, int b,
6083 +             MapReduceEntriesToDoubleTask<K,V> nextRight,
6084 +             ObjectToDouble<Map.Entry<K,V>> transformer,
6085 +             double basis,
6086 +             DoubleByDoubleToDouble reducer) {
6087 +            super(p, b); this.nextRight = nextRight;
6088 +            this.transformer = transformer;
6089 +            this.basis = basis; this.reducer = reducer;
6090 +        }
6091 +        @SuppressWarnings("unchecked") public final boolean exec() {
6092 +            final ObjectToDouble<Map.Entry<K,V>> transformer =
6093 +                this.transformer;
6094 +            final DoubleByDoubleToDouble reducer = this.reducer;
6095 +            if (transformer == null || reducer == null)
6096 +                return abortOnNullFunction();
6097 +            try {
6098 +                final double id = this.basis;
6099 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6100 +                    do {} while (!casPending(c = pending, c+1));
6101 +                    (rights = new MapReduceEntriesToDoubleTask<K,V>
6102 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6103 +                }
6104 +                double r = id;
6105 +                Object v;
6106 +                while ((v = advance()) != null)
6107 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6108 +                result = r;
6109 +                for (MapReduceEntriesToDoubleTask<K,V> t = this, s;;) {
6110 +                    int c; BulkTask<K,V,?> par;
6111 +                    if ((c = t.pending) == 0) {
6112 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6113 +                            t.result = reducer.apply(t.result, s.result);
6114 +                        }
6115 +                        if ((par = t.parent) == null ||
6116 +                            !(par instanceof MapReduceEntriesToDoubleTask)) {
6117 +                            t.quietlyComplete();
6118 +                            break;
6119 +                        }
6120 +                        t = (MapReduceEntriesToDoubleTask<K,V>)par;
6121 +                    }
6122 +                    else if (t.casPending(c, c - 1))
6123 +                        break;
6124 +                }
6125 +            } catch (Throwable ex) {
6126 +                return tryCompleteComputation(ex);
6127 +            }
6128 +            return false;
6129 +        }
6130 +        public final Double getRawResult() { return result; }
6131 +    }
6132 +
6133 +    @SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6134 +        extends BulkTask<K,V,Double> {
6135 +        final ObjectByObjectToDouble<? super K, ? super V> transformer;
6136 +        final DoubleByDoubleToDouble reducer;
6137 +        final double basis;
6138 +        double result;
6139 +        MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6140 +        MapReduceMappingsToDoubleTask
6141 +            (ConcurrentHashMapV8<K,V> m,
6142 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
6143 +             double basis,
6144 +             DoubleByDoubleToDouble reducer) {
6145 +            super(m);
6146 +            this.transformer = transformer;
6147 +            this.basis = basis; this.reducer = reducer;
6148 +        }
6149 +        MapReduceMappingsToDoubleTask
6150 +            (BulkTask<K,V,?> p, int b,
6151 +             MapReduceMappingsToDoubleTask<K,V> nextRight,
6152 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
6153 +             double basis,
6154 +             DoubleByDoubleToDouble reducer) {
6155 +            super(p, b); this.nextRight = nextRight;
6156 +            this.transformer = transformer;
6157 +            this.basis = basis; this.reducer = reducer;
6158 +        }
6159 +        @SuppressWarnings("unchecked") public final boolean exec() {
6160 +            final ObjectByObjectToDouble<? super K, ? super V> transformer =
6161 +                this.transformer;
6162 +            final DoubleByDoubleToDouble reducer = this.reducer;
6163 +            if (transformer == null || reducer == null)
6164 +                return abortOnNullFunction();
6165 +            try {
6166 +                final double id = this.basis;
6167 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6168 +                    do {} while (!casPending(c = pending, c+1));
6169 +                    (rights = new MapReduceMappingsToDoubleTask<K,V>
6170 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6171 +                }
6172 +                double r = id;
6173 +                Object v;
6174 +                while ((v = advance()) != null)
6175 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6176 +                result = r;
6177 +                for (MapReduceMappingsToDoubleTask<K,V> t = this, s;;) {
6178 +                    int c; BulkTask<K,V,?> par;
6179 +                    if ((c = t.pending) == 0) {
6180 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6181 +                            t.result = reducer.apply(t.result, s.result);
6182 +                        }
6183 +                        if ((par = t.parent) == null ||
6184 +                            !(par instanceof MapReduceMappingsToDoubleTask)) {
6185 +                            t.quietlyComplete();
6186 +                            break;
6187 +                        }
6188 +                        t = (MapReduceMappingsToDoubleTask<K,V>)par;
6189 +                    }
6190 +                    else if (t.casPending(c, c - 1))
6191 +                        break;
6192 +                }
6193 +            } catch (Throwable ex) {
6194 +                return tryCompleteComputation(ex);
6195 +            }
6196 +            return false;
6197 +        }
6198 +        public final Double getRawResult() { return result; }
6199 +    }
6200 +
6201 +    @SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6202 +        extends BulkTask<K,V,Long> {
6203 +        final ObjectToLong<? super K> transformer;
6204 +        final LongByLongToLong reducer;
6205 +        final long basis;
6206 +        long result;
6207 +        MapReduceKeysToLongTask<K,V> rights, nextRight;
6208 +        MapReduceKeysToLongTask
6209 +            (ConcurrentHashMapV8<K,V> m,
6210 +             ObjectToLong<? super K> transformer,
6211 +             long basis,
6212 +             LongByLongToLong reducer) {
6213 +            super(m);
6214 +            this.transformer = transformer;
6215 +            this.basis = basis; this.reducer = reducer;
6216 +        }
6217 +        MapReduceKeysToLongTask
6218 +            (BulkTask<K,V,?> p, int b,
6219 +             MapReduceKeysToLongTask<K,V> nextRight,
6220 +             ObjectToLong<? super K> transformer,
6221 +             long basis,
6222 +             LongByLongToLong reducer) {
6223 +            super(p, b); this.nextRight = nextRight;
6224 +            this.transformer = transformer;
6225 +            this.basis = basis; this.reducer = reducer;
6226 +        }
6227 +        @SuppressWarnings("unchecked") public final boolean exec() {
6228 +            final ObjectToLong<? super K> transformer =
6229 +                this.transformer;
6230 +            final LongByLongToLong reducer = this.reducer;
6231 +            if (transformer == null || reducer == null)
6232 +                return abortOnNullFunction();
6233 +            try {
6234 +                final long id = this.basis;
6235 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6236 +                    do {} while (!casPending(c = pending, c+1));
6237 +                    (rights = new MapReduceKeysToLongTask<K,V>
6238 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6239 +                }
6240 +                long r = id;
6241 +                while (advance() != null)
6242 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6243 +                result = r;
6244 +                for (MapReduceKeysToLongTask<K,V> t = this, s;;) {
6245 +                    int c; BulkTask<K,V,?> par;
6246 +                    if ((c = t.pending) == 0) {
6247 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6248 +                            t.result = reducer.apply(t.result, s.result);
6249 +                        }
6250 +                        if ((par = t.parent) == null ||
6251 +                            !(par instanceof MapReduceKeysToLongTask)) {
6252 +                            t.quietlyComplete();
6253 +                            break;
6254 +                        }
6255 +                        t = (MapReduceKeysToLongTask<K,V>)par;
6256 +                    }
6257 +                    else if (t.casPending(c, c - 1))
6258 +                        break;
6259 +                }
6260 +            } catch (Throwable ex) {
6261 +                return tryCompleteComputation(ex);
6262 +            }
6263 +            return false;
6264 +        }
6265 +        public final Long getRawResult() { return result; }
6266 +    }
6267 +
6268 +    @SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6269 +        extends BulkTask<K,V,Long> {
6270 +        final ObjectToLong<? super V> transformer;
6271 +        final LongByLongToLong reducer;
6272 +        final long basis;
6273 +        long result;
6274 +        MapReduceValuesToLongTask<K,V> rights, nextRight;
6275 +        MapReduceValuesToLongTask
6276 +            (ConcurrentHashMapV8<K,V> m,
6277 +             ObjectToLong<? super V> transformer,
6278 +             long basis,
6279 +             LongByLongToLong reducer) {
6280 +            super(m);
6281 +            this.transformer = transformer;
6282 +            this.basis = basis; this.reducer = reducer;
6283 +        }
6284 +        MapReduceValuesToLongTask
6285 +            (BulkTask<K,V,?> p, int b,
6286 +             MapReduceValuesToLongTask<K,V> nextRight,
6287 +             ObjectToLong<? super V> transformer,
6288 +             long basis,
6289 +             LongByLongToLong reducer) {
6290 +            super(p, b); this.nextRight = nextRight;
6291 +            this.transformer = transformer;
6292 +            this.basis = basis; this.reducer = reducer;
6293 +        }
6294 +        @SuppressWarnings("unchecked") public final boolean exec() {
6295 +            final ObjectToLong<? super V> transformer =
6296 +                this.transformer;
6297 +            final LongByLongToLong reducer = this.reducer;
6298 +            if (transformer == null || reducer == null)
6299 +                return abortOnNullFunction();
6300 +            try {
6301 +                final long id = this.basis;
6302 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6303 +                    do {} while (!casPending(c = pending, c+1));
6304 +                    (rights = new MapReduceValuesToLongTask<K,V>
6305 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6306 +                }
6307 +                long r = id;
6308 +                Object v;
6309 +                while ((v = advance()) != null)
6310 +                    r = reducer.apply(r, transformer.apply((V)v));
6311 +                result = r;
6312 +                for (MapReduceValuesToLongTask<K,V> t = this, s;;) {
6313 +                    int c; BulkTask<K,V,?> par;
6314 +                    if ((c = t.pending) == 0) {
6315 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6316 +                            t.result = reducer.apply(t.result, s.result);
6317 +                        }
6318 +                        if ((par = t.parent) == null ||
6319 +                            !(par instanceof MapReduceValuesToLongTask)) {
6320 +                            t.quietlyComplete();
6321 +                            break;
6322 +                        }
6323 +                        t = (MapReduceValuesToLongTask<K,V>)par;
6324 +                    }
6325 +                    else if (t.casPending(c, c - 1))
6326 +                        break;
6327 +                }
6328 +            } catch (Throwable ex) {
6329 +                return tryCompleteComputation(ex);
6330 +            }
6331 +            return false;
6332 +        }
6333 +        public final Long getRawResult() { return result; }
6334 +    }
6335 +
6336 +    @SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6337 +        extends BulkTask<K,V,Long> {
6338 +        final ObjectToLong<Map.Entry<K,V>> transformer;
6339 +        final LongByLongToLong reducer;
6340 +        final long basis;
6341 +        long result;
6342 +        MapReduceEntriesToLongTask<K,V> rights, nextRight;
6343 +        MapReduceEntriesToLongTask
6344 +            (ConcurrentHashMapV8<K,V> m,
6345 +             ObjectToLong<Map.Entry<K,V>> transformer,
6346 +             long basis,
6347 +             LongByLongToLong reducer) {
6348 +            super(m);
6349 +            this.transformer = transformer;
6350 +            this.basis = basis; this.reducer = reducer;
6351 +        }
6352 +        MapReduceEntriesToLongTask
6353 +            (BulkTask<K,V,?> p, int b,
6354 +             MapReduceEntriesToLongTask<K,V> nextRight,
6355 +             ObjectToLong<Map.Entry<K,V>> transformer,
6356 +             long basis,
6357 +             LongByLongToLong reducer) {
6358 +            super(p, b); this.nextRight = nextRight;
6359 +            this.transformer = transformer;
6360 +            this.basis = basis; this.reducer = reducer;
6361 +        }
6362 +        @SuppressWarnings("unchecked") public final boolean exec() {
6363 +            final ObjectToLong<Map.Entry<K,V>> transformer =
6364 +                this.transformer;
6365 +            final LongByLongToLong reducer = this.reducer;
6366 +            if (transformer == null || reducer == null)
6367 +                return abortOnNullFunction();
6368 +            try {
6369 +                final long id = this.basis;
6370 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6371 +                    do {} while (!casPending(c = pending, c+1));
6372 +                    (rights = new MapReduceEntriesToLongTask<K,V>
6373 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6374 +                }
6375 +                long r = id;
6376 +                Object v;
6377 +                while ((v = advance()) != null)
6378 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6379 +                result = r;
6380 +                for (MapReduceEntriesToLongTask<K,V> t = this, s;;) {
6381 +                    int c; BulkTask<K,V,?> par;
6382 +                    if ((c = t.pending) == 0) {
6383 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6384 +                            t.result = reducer.apply(t.result, s.result);
6385 +                        }
6386 +                        if ((par = t.parent) == null ||
6387 +                            !(par instanceof MapReduceEntriesToLongTask)) {
6388 +                            t.quietlyComplete();
6389 +                            break;
6390 +                        }
6391 +                        t = (MapReduceEntriesToLongTask<K,V>)par;
6392 +                    }
6393 +                    else if (t.casPending(c, c - 1))
6394 +                        break;
6395 +                }
6396 +            } catch (Throwable ex) {
6397 +                return tryCompleteComputation(ex);
6398 +            }
6399 +            return false;
6400 +        }
6401 +        public final Long getRawResult() { return result; }
6402 +    }
6403 +
6404 +    @SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6405 +        extends BulkTask<K,V,Long> {
6406 +        final ObjectByObjectToLong<? super K, ? super V> transformer;
6407 +        final LongByLongToLong reducer;
6408 +        final long basis;
6409 +        long result;
6410 +        MapReduceMappingsToLongTask<K,V> rights, nextRight;
6411 +        MapReduceMappingsToLongTask
6412 +            (ConcurrentHashMapV8<K,V> m,
6413 +             ObjectByObjectToLong<? super K, ? super V> transformer,
6414 +             long basis,
6415 +             LongByLongToLong reducer) {
6416 +            super(m);
6417 +            this.transformer = transformer;
6418 +            this.basis = basis; this.reducer = reducer;
6419 +        }
6420 +        MapReduceMappingsToLongTask
6421 +            (BulkTask<K,V,?> p, int b,
6422 +             MapReduceMappingsToLongTask<K,V> nextRight,
6423 +             ObjectByObjectToLong<? super K, ? super V> transformer,
6424 +             long basis,
6425 +             LongByLongToLong reducer) {
6426 +            super(p, b); this.nextRight = nextRight;
6427 +            this.transformer = transformer;
6428 +            this.basis = basis; this.reducer = reducer;
6429 +        }
6430 +        @SuppressWarnings("unchecked") public final boolean exec() {
6431 +            final ObjectByObjectToLong<? super K, ? super V> transformer =
6432 +                this.transformer;
6433 +            final LongByLongToLong reducer = this.reducer;
6434 +            if (transformer == null || reducer == null)
6435 +                return abortOnNullFunction();
6436 +            try {
6437 +                final long id = this.basis;
6438 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6439 +                    do {} while (!casPending(c = pending, c+1));
6440 +                    (rights = new MapReduceMappingsToLongTask<K,V>
6441 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6442 +                }
6443 +                long r = id;
6444 +                Object v;
6445 +                while ((v = advance()) != null)
6446 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6447 +                result = r;
6448 +                for (MapReduceMappingsToLongTask<K,V> t = this, s;;) {
6449 +                    int c; BulkTask<K,V,?> par;
6450 +                    if ((c = t.pending) == 0) {
6451 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6452 +                            t.result = reducer.apply(t.result, s.result);
6453 +                        }
6454 +                        if ((par = t.parent) == null ||
6455 +                            !(par instanceof MapReduceMappingsToLongTask)) {
6456 +                            t.quietlyComplete();
6457 +                            break;
6458 +                        }
6459 +                        t = (MapReduceMappingsToLongTask<K,V>)par;
6460 +                    }
6461 +                    else if (t.casPending(c, c - 1))
6462 +                        break;
6463 +                }
6464 +            } catch (Throwable ex) {
6465 +                return tryCompleteComputation(ex);
6466 +            }
6467 +            return false;
6468 +        }
6469 +        public final Long getRawResult() { return result; }
6470 +    }
6471 +
6472 +    @SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6473 +        extends BulkTask<K,V,Integer> {
6474 +        final ObjectToInt<? super K> transformer;
6475 +        final IntByIntToInt reducer;
6476 +        final int basis;
6477 +        int result;
6478 +        MapReduceKeysToIntTask<K,V> rights, nextRight;
6479 +        MapReduceKeysToIntTask
6480 +            (ConcurrentHashMapV8<K,V> m,
6481 +             ObjectToInt<? super K> transformer,
6482 +             int basis,
6483 +             IntByIntToInt reducer) {
6484 +            super(m);
6485 +            this.transformer = transformer;
6486 +            this.basis = basis; this.reducer = reducer;
6487 +        }
6488 +        MapReduceKeysToIntTask
6489 +            (BulkTask<K,V,?> p, int b,
6490 +             MapReduceKeysToIntTask<K,V> nextRight,
6491 +             ObjectToInt<? super K> transformer,
6492 +             int basis,
6493 +             IntByIntToInt reducer) {
6494 +            super(p, b); this.nextRight = nextRight;
6495 +            this.transformer = transformer;
6496 +            this.basis = basis; this.reducer = reducer;
6497 +        }
6498 +        @SuppressWarnings("unchecked") public final boolean exec() {
6499 +            final ObjectToInt<? super K> transformer =
6500 +                this.transformer;
6501 +            final IntByIntToInt reducer = this.reducer;
6502 +            if (transformer == null || reducer == null)
6503 +                return abortOnNullFunction();
6504 +            try {
6505 +                final int id = this.basis;
6506 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6507 +                    do {} while (!casPending(c = pending, c+1));
6508 +                    (rights = new MapReduceKeysToIntTask<K,V>
6509 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6510 +                }
6511 +                int r = id;
6512 +                while (advance() != null)
6513 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6514 +                result = r;
6515 +                for (MapReduceKeysToIntTask<K,V> t = this, s;;) {
6516 +                    int c; BulkTask<K,V,?> par;
6517 +                    if ((c = t.pending) == 0) {
6518 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6519 +                            t.result = reducer.apply(t.result, s.result);
6520 +                        }
6521 +                        if ((par = t.parent) == null ||
6522 +                            !(par instanceof MapReduceKeysToIntTask)) {
6523 +                            t.quietlyComplete();
6524 +                            break;
6525 +                        }
6526 +                        t = (MapReduceKeysToIntTask<K,V>)par;
6527 +                    }
6528 +                    else if (t.casPending(c, c - 1))
6529 +                        break;
6530 +                }
6531 +            } catch (Throwable ex) {
6532 +                return tryCompleteComputation(ex);
6533 +            }
6534 +            return false;
6535 +        }
6536 +        public final Integer getRawResult() { return result; }
6537 +    }
6538 +
6539 +    @SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6540 +        extends BulkTask<K,V,Integer> {
6541 +        final ObjectToInt<? super V> transformer;
6542 +        final IntByIntToInt reducer;
6543 +        final int basis;
6544 +        int result;
6545 +        MapReduceValuesToIntTask<K,V> rights, nextRight;
6546 +        MapReduceValuesToIntTask
6547 +            (ConcurrentHashMapV8<K,V> m,
6548 +             ObjectToInt<? super V> transformer,
6549 +             int basis,
6550 +             IntByIntToInt reducer) {
6551 +            super(m);
6552 +            this.transformer = transformer;
6553 +            this.basis = basis; this.reducer = reducer;
6554 +        }
6555 +        MapReduceValuesToIntTask
6556 +            (BulkTask<K,V,?> p, int b,
6557 +             MapReduceValuesToIntTask<K,V> nextRight,
6558 +             ObjectToInt<? super V> transformer,
6559 +             int basis,
6560 +             IntByIntToInt reducer) {
6561 +            super(p, b); this.nextRight = nextRight;
6562 +            this.transformer = transformer;
6563 +            this.basis = basis; this.reducer = reducer;
6564 +        }
6565 +        @SuppressWarnings("unchecked") public final boolean exec() {
6566 +            final ObjectToInt<? super V> transformer =
6567 +                this.transformer;
6568 +            final IntByIntToInt reducer = this.reducer;
6569 +            if (transformer == null || reducer == null)
6570 +                return abortOnNullFunction();
6571 +            try {
6572 +                final int id = this.basis;
6573 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6574 +                    do {} while (!casPending(c = pending, c+1));
6575 +                    (rights = new MapReduceValuesToIntTask<K,V>
6576 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6577 +                }
6578 +                int r = id;
6579 +                Object v;
6580 +                while ((v = advance()) != null)
6581 +                    r = reducer.apply(r, transformer.apply((V)v));
6582 +                result = r;
6583 +                for (MapReduceValuesToIntTask<K,V> t = this, s;;) {
6584 +                    int c; BulkTask<K,V,?> par;
6585 +                    if ((c = t.pending) == 0) {
6586 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6587 +                            t.result = reducer.apply(t.result, s.result);
6588 +                        }
6589 +                        if ((par = t.parent) == null ||
6590 +                            !(par instanceof MapReduceValuesToIntTask)) {
6591 +                            t.quietlyComplete();
6592 +                            break;
6593 +                        }
6594 +                        t = (MapReduceValuesToIntTask<K,V>)par;
6595 +                    }
6596 +                    else if (t.casPending(c, c - 1))
6597 +                        break;
6598 +                }
6599 +            } catch (Throwable ex) {
6600 +                return tryCompleteComputation(ex);
6601 +            }
6602 +            return false;
6603 +        }
6604 +        public final Integer getRawResult() { return result; }
6605 +    }
6606 +
6607 +    @SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6608 +        extends BulkTask<K,V,Integer> {
6609 +        final ObjectToInt<Map.Entry<K,V>> transformer;
6610 +        final IntByIntToInt reducer;
6611 +        final int basis;
6612 +        int result;
6613 +        MapReduceEntriesToIntTask<K,V> rights, nextRight;
6614 +        MapReduceEntriesToIntTask
6615 +            (ConcurrentHashMapV8<K,V> m,
6616 +             ObjectToInt<Map.Entry<K,V>> transformer,
6617 +             int basis,
6618 +             IntByIntToInt reducer) {
6619 +            super(m);
6620 +            this.transformer = transformer;
6621 +            this.basis = basis; this.reducer = reducer;
6622 +        }
6623 +        MapReduceEntriesToIntTask
6624 +            (BulkTask<K,V,?> p, int b,
6625 +             MapReduceEntriesToIntTask<K,V> nextRight,
6626 +             ObjectToInt<Map.Entry<K,V>> transformer,
6627 +             int basis,
6628 +             IntByIntToInt reducer) {
6629 +            super(p, b); this.nextRight = nextRight;
6630 +            this.transformer = transformer;
6631 +            this.basis = basis; this.reducer = reducer;
6632 +        }
6633 +        @SuppressWarnings("unchecked") public final boolean exec() {
6634 +            final ObjectToInt<Map.Entry<K,V>> transformer =
6635 +                this.transformer;
6636 +            final IntByIntToInt reducer = this.reducer;
6637 +            if (transformer == null || reducer == null)
6638 +                return abortOnNullFunction();
6639 +            try {
6640 +                final int id = this.basis;
6641 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6642 +                    do {} while (!casPending(c = pending, c+1));
6643 +                    (rights = new MapReduceEntriesToIntTask<K,V>
6644 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6645 +                }
6646 +                int r = id;
6647 +                Object v;
6648 +                while ((v = advance()) != null)
6649 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6650 +                result = r;
6651 +                for (MapReduceEntriesToIntTask<K,V> t = this, s;;) {
6652 +                    int c; BulkTask<K,V,?> par;
6653 +                    if ((c = t.pending) == 0) {
6654 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6655 +                            t.result = reducer.apply(t.result, s.result);
6656 +                        }
6657 +                        if ((par = t.parent) == null ||
6658 +                            !(par instanceof MapReduceEntriesToIntTask)) {
6659 +                            t.quietlyComplete();
6660 +                            break;
6661 +                        }
6662 +                        t = (MapReduceEntriesToIntTask<K,V>)par;
6663 +                    }
6664 +                    else if (t.casPending(c, c - 1))
6665 +                        break;
6666 +                }
6667 +            } catch (Throwable ex) {
6668 +                return tryCompleteComputation(ex);
6669 +            }
6670 +            return false;
6671 +        }
6672 +        public final Integer getRawResult() { return result; }
6673 +    }
6674 +
6675 +    @SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6676 +        extends BulkTask<K,V,Integer> {
6677 +        final ObjectByObjectToInt<? super K, ? super V> transformer;
6678 +        final IntByIntToInt reducer;
6679 +        final int basis;
6680 +        int result;
6681 +        MapReduceMappingsToIntTask<K,V> rights, nextRight;
6682 +        MapReduceMappingsToIntTask
6683 +            (ConcurrentHashMapV8<K,V> m,
6684 +             ObjectByObjectToInt<? super K, ? super V> transformer,
6685 +             int basis,
6686 +             IntByIntToInt reducer) {
6687 +            super(m);
6688 +            this.transformer = transformer;
6689 +            this.basis = basis; this.reducer = reducer;
6690 +        }
6691 +        MapReduceMappingsToIntTask
6692 +            (BulkTask<K,V,?> p, int b,
6693 +             MapReduceMappingsToIntTask<K,V> nextRight,
6694 +             ObjectByObjectToInt<? super K, ? super V> transformer,
6695 +             int basis,
6696 +             IntByIntToInt reducer) {
6697 +            super(p, b); this.nextRight = nextRight;
6698 +            this.transformer = transformer;
6699 +            this.basis = basis; this.reducer = reducer;
6700 +        }
6701 +        @SuppressWarnings("unchecked") public final boolean exec() {
6702 +            final ObjectByObjectToInt<? super K, ? super V> transformer =
6703 +                this.transformer;
6704 +            final IntByIntToInt reducer = this.reducer;
6705 +            if (transformer == null || reducer == null)
6706 +                return abortOnNullFunction();
6707 +            try {
6708 +                final int id = this.basis;
6709 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6710 +                    do {} while (!casPending(c = pending, c+1));
6711 +                    (rights = new MapReduceMappingsToIntTask<K,V>
6712 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6713 +                }
6714 +                int r = id;
6715 +                Object v;
6716 +                while ((v = advance()) != null)
6717 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6718 +                result = r;
6719 +                for (MapReduceMappingsToIntTask<K,V> t = this, s;;) {
6720 +                    int c; BulkTask<K,V,?> par;
6721 +                    if ((c = t.pending) == 0) {
6722 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6723 +                            t.result = reducer.apply(t.result, s.result);
6724 +                        }
6725 +                        if ((par = t.parent) == null ||
6726 +                            !(par instanceof MapReduceMappingsToIntTask)) {
6727 +                            t.quietlyComplete();
6728 +                            break;
6729 +                        }
6730 +                        t = (MapReduceMappingsToIntTask<K,V>)par;
6731 +                    }
6732 +                    else if (t.casPending(c, c - 1))
6733 +                        break;
6734 +                }
6735 +            } catch (Throwable ex) {
6736 +                return tryCompleteComputation(ex);
6737 +            }
6738 +            return false;
6739 +        }
6740 +        public final Integer getRawResult() { return result; }
6741 +    }
6742 +
6743 +
6744      // Unsafe mechanics
6745      private static final sun.misc.Unsafe UNSAFE;
6746      private static final long counterOffset;
6747 <    private static final long resizingOffset;
6747 >    private static final long sizeCtlOffset;
6748      private static final long ABASE;
6749      private static final int ASHIFT;
6750  
# Line 1579 | Line 6755 | public class ConcurrentHashMapV8<K, V>
6755              Class<?> k = ConcurrentHashMapV8.class;
6756              counterOffset = UNSAFE.objectFieldOffset
6757                  (k.getDeclaredField("counter"));
6758 <            resizingOffset = UNSAFE.objectFieldOffset
6759 <                (k.getDeclaredField("resizing"));
6758 >            sizeCtlOffset = UNSAFE.objectFieldOffset
6759 >                (k.getDeclaredField("sizeCtl"));
6760              Class<?> sc = Node[].class;
6761              ABASE = UNSAFE.arrayBaseOffset(sc);
6762              ss = UNSAFE.arrayIndexScale(sc);
# Line 1619 | Line 6795 | public class ConcurrentHashMapV8<K, V>
6795              }
6796          }
6797      }
1622
6798   }

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