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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.21 by jsr166, Sat Sep 10 05:35:24 2011 UTC vs.
Revision 1.61 by dl, Thu Sep 13 10:41:37 2012 UTC

# Line 6 | Line 6
6  
7   package jsr166e;
8   import jsr166e.LongAdder;
9 + import jsr166e.ForkJoinPool;
10 + import jsr166e.ForkJoinTask;
11 +
12 + import java.util.Comparator;
13 + import java.util.Arrays;
14   import java.util.Map;
15   import java.util.Set;
16   import java.util.Collection;
# Line 19 | Line 24 | import java.util.Enumeration;
24   import java.util.ConcurrentModificationException;
25   import java.util.NoSuchElementException;
26   import java.util.concurrent.ConcurrentMap;
27 + import java.util.concurrent.ThreadLocalRandom;
28 + import java.util.concurrent.locks.LockSupport;
29 + import java.util.concurrent.locks.AbstractQueuedSynchronizer;
30 + import java.util.concurrent.atomic.AtomicReference;
31 +
32   import java.io.Serializable;
33  
34   /**
# Line 37 | Line 47 | import java.io.Serializable;
47   * block, so may overlap with update operations (including {@code put}
48   * and {@code remove}). Retrievals reflect the results of the most
49   * recently <em>completed</em> update operations holding upon their
50 < * onset.  For aggregate operations such as {@code putAll} and {@code
51 < * clear}, concurrent retrievals may reflect insertion or removal of
52 < * only some entries.  Similarly, Iterators and Enumerations return
53 < * elements reflecting the state of the hash table at some point at or
54 < * since the creation of the iterator/enumeration.  They do
55 < * <em>not</em> throw {@link ConcurrentModificationException}.
56 < * However, iterators are designed to be used by only one thread at a
57 < * time.  Bear in mind that the results of aggregate status methods
58 < * including {@code size}, {@code isEmpty}, and {@code containsValue}
59 < * are typically useful only when a map is not undergoing concurrent
60 < * updates in other threads.  Otherwise the results of these methods
61 < * reflect transient states that may be adequate for monitoring
62 < * or estimation 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> 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. There may be
71 < * much variance around this average as mappings are added and
72 < * removed, but overall, this maintains a commonly accepted time/space
73 < * tradeoff for hash tables.  However, resizing this or any other kind
74 < * of hash table may be a relatively slow operation. When possible, it
75 < * is a good idea to provide a size estimate as an optional {@code
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
# Line 68 | Line 82 | import java.io.Serializable;
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
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
# Line 83 | 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 1.8
104 > * @since 1.5
105   * @author Doug Lea
106   * @param <K> the type of keys maintained by this map
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 121 | 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
# Line 129 | Line 195 | public class ConcurrentHashMapV8<K, V>
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.
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 list of
207 <     * Nodes (most often, zero or one Node).  Table accesses require
208 <     * volatile/atomic reads, writes, and CASes.  Because there is no
209 <     * other way to arrange this without adding further indirections,
210 <     * we use intrinsics (sun.misc.Unsafe) operations.  The lists of
211 <     * nodes within bins are always accurately traversable under
212 <     * volatile reads, so long as lookups check hash code and
213 <     * non-nullness of value before checking key equality. (All valid
214 <     * hash codes are nonnegative. Negative values are reserved for
215 <     * special forwarding nodes; see below.)
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 putIfAbsent) of the first node in an
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 <     * on average by far the most common case for put operations.
233 <     * Other update operations (insert, delete, and replace) require
234 <     * locks.  We do not want to waste the space required to associate
235 <     * a distinct lock object with each bin, so instead use the first
236 <     * node of a bin list itself as a lock, using plain "synchronized"
237 <     * locks. These save space and we can live with block-structured
238 <     * lock/unlock operations. Using the first node of a list as a
239 <     * lock does not by itself suffice though: When a node is locked,
240 <     * any update must first validate that it is still the first node,
241 <     * and retry if not. Because new nodes are always appended to
242 <     * lists, once a node is first in a bin, it remains first until
243 <     * deleted or the bin becomes invalidated.  However, operations
244 <     * that only conditionally update can and sometimes do inspect
245 <     * nodes until the point of update. This is a converse of sorts to
246 <     * the lazy locking technique described by Herlihy & Shavit.
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 this approach is that most update
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, this is
258 <     * not a common enough problem to outweigh the time/space overhead
259 <     * of alternatives: Under random hash codes, the frequency of
170 <     * nodes in bins follows a Poisson distribution
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 few values are:
265 >     * first values are:
266       *
267 <     * 0:    0.607
268 <     * 1:    0.303
269 <     * 2:    0.076
270 <     * 3:    0.012
271 <     * more: 0.002
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).  Function "spread"
280 <     * performs hashCode randomization that improves the likelihood
281 <     * that these assumptions hold unless users define exactly the
282 <     * same value for too many hashCodes.
283 <     *
284 <     * The table is resized when occupancy exceeds a threshold.  Only
285 <     * a single thread performs the resize (using field "resizing", to
286 <     * arrange exclusion), but the table otherwise remains usable for
287 <     * reads and updates. Resizing proceeds by transferring bins, one
288 <     * by one, from the table to the next table.  Upon transfer, the
289 <     * old table bin contains only a special forwarding node (with
290 <     * negative hash field) that contains the next table as its
291 <     * key. On encountering a forwarding node, access and update
292 <     * operations restart, using the new table. To ensure concurrent
293 <     * readability of traversals, transfers must proceed from the last
294 <     * bin (table.length - 1) up towards the first.  Upon seeing a
295 <     * forwarding node, traversals (see class InternalIterator)
296 <     * arrange to move to the new table for the rest of the traversal
297 <     * without revisiting nodes.  This constrains bin transfers to a
298 <     * particular order, and so can block indefinitely waiting for the
299 <     * next lock, and other threads cannot help with the transfer.
300 <     * However, expected stalls are infrequent enough to not warrant
301 <     * the additional overhead of access and iteration schemes that
302 <     * could admit out-of-order or concurrent bin transfers.
303 <     *
304 <     * This traversal scheme also applies to partial traversals of
305 <     * ranges of bins (via an alternate InternalIterator constructor)
306 <     * to support partitioned aggregate operations (that are not
307 <     * otherwise implemented yet).  Also, read-only operations give up
308 <     * if ever forwarded to a null table, which provides support for
309 <     * shutdown-style clearing, which is also not currently
310 <     * implemented.
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.
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 targetCapacity used in
353 <     * growTable. These harmlessly fail to take effect in cases of
223 <     * races with other ongoing resizings. Uses of the threshold and
224 <     * targetCapacity during attempted initializations or resizings
225 <     * are racy but fall back on checks to preserve correctness.
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 access. To avoid reading so
358 <     * often, resizing is normally attempted only upon adding to a bin
359 <     * already holding two or more nodes. Under uniform hash
360 <     * distributions, the probability of this occurring at threshold
361 <     * is around 13%, meaning that only about 1 in 8 puts check
362 <     * threshold (and after resizing, many fewer do so). But this
363 <     * approximation has high variance for small table sizes, so we
364 <     * check on any collision for sizes <= 64.  Further, to increase
365 <     * the probability that a resize occurs soon enough, we offset the
366 <     * threshold (see THRESHOLD_OFFSET) by the expected number of puts
367 <     * between checks.
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 also declare an unused "Segment" class
374 <     * that is instantiated in minimal form only when serializing.
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 -------------- */
# Line 250 | Line 382 | public class ConcurrentHashMapV8<K, V>
382      /**
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.
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      private static final int MAXIMUM_CAPACITY = 1 << 30;
390  
# Line 261 | Line 395 | public class ConcurrentHashMapV8<K, V>
395      private static final int DEFAULT_CAPACITY = 16;
396  
397      /**
398 <     * The load factor for this table. Overrides of this value in
399 <     * constructors affect only the initial table capacity.  The
266 <     * actual floating point value isn't normally used, because it is
267 <     * simpler to rely on the expression {@code n - (n >>> 2)} for the
268 <     * associated resizing threshold.
398 >     * The largest possible (non-power of two) array size.
399 >     * Needed by toArray and related methods.
400       */
401 <    private static final float LOAD_FACTOR = 0.75f;
401 >    static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
402  
403      /**
404 <     * The count value to offset thresholds to compensate for checking
405 <     * for the need to resize only when inserting into bins with two
275 <     * or more elements. See above for explanation.
404 >     * The default concurrency level for this table. Unused but
405 >     * defined for compatibility with previous versions of this class.
406       */
407 <    private static final int THRESHOLD_OFFSET = 8;
407 >    private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
408  
409      /**
410 <     * The default concurrency level for this table. Unused except as
411 <     * a sizing hint, but defined for compatibility with previous
412 <     * 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 <    private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
285 <
286 <    /* ---------------- Nodes -------------- */
416 >    private static final float LOAD_FACTOR = 0.75f;
417  
418      /**
419 <     * Key-value entry. Note that this is never exported out as a
420 <     * user-visible Map.Entry. Nodes with a negative hash field are
421 <     * special, and do not contain user keys or values.  Otherwise,
292 <     * keys are never null, and null val fields indicate that a node
293 <     * is in the process of being deleted or created. For purposes of
294 <     * read-only, access, a key may be read before a val, but can only
295 <     * be used after checking val.  (For an update operation, when a
296 <     * lock is held on a node, order doesn't matter.)
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 class Node {
299 <        final int hash;
300 <        final Object key;
301 <        volatile Object val;
302 <        volatile Node next;
303 <
304 <        Node(int hash, Object key, Object val, Node next) {
305 <            this.hash = hash;
306 <            this.key = key;
307 <            this.val = val;
308 <            this.next = next;
309 <        }
310 <    }
423 >    private static final int TRANSFER_BUFFER_SIZE = 32;
424  
425      /**
426 <     * Sign bit of node hash value indicating to use table in node.key.
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 <    private static final int SIGN_BIT = 0x80000000;
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  
# Line 322 | Line 446 | public class ConcurrentHashMapV8<K, V>
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 next element count value upon which to resize the table. */
456 <    private transient int threshold;
457 <    /** The target capacity; volatile to cover initialization races. */
458 <    private transient volatile int targetCapacity;
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      private transient KeySet<K,V> keySet;
# Line 353 | Line 482 | public class ConcurrentHashMapV8<K, V>
482       * inline assignments below.
483       */
484  
485 <    static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
485 >    static final Node tabAt(Node[] tab, int i) { // used by Iter
486          return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
487      }
488  
# Line 365 | Line 494 | public class ConcurrentHashMapV8<K, V>
494          UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
495      }
496  
497 <    /* ----------------Table Initialization and Resizing -------------- */
497 >    /* ---------------- Nodes -------------- */
498  
499      /**
500 <     * Returns a power of two table size for the given desired capacity.
501 <     * See Hackers Delight, sec 3.2
500 >     * Key-value entry. Note that this is never exported out as a
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 <    private static final int tableSizeFor(int c) {
510 <        int n = c - 1;
511 <        n |= n >>> 1;
512 <        n |= n >>> 2;
513 <        n |= n >>> 4;
379 <        n |= n >>> 8;
380 <        n |= n >>> 16;
381 <        return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
382 <    }
509 >    static class Node {
510 >        volatile int hash;
511 >        final Object key;
512 >        volatile Object val;
513 >        volatile Node next;
514  
515 <    /**
516 <     * If not already resizing, initializes or creates next table and
517 <     * transfers bins. Initial table size uses the capacity recorded
518 <     * in targetCapacity.  Rechecks occupancy after a transfer to see
519 <     * if another resize is already needed because resizings are
520 <     * lagging additions.
521 <     *
522 <     * @return current table
523 <     */
524 <    private final Node[] growTable() {
525 <        if (resizing == 0 &&
526 <            UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
527 <            try {
528 <                for (;;) {
529 <                    Node[] tab = table;
530 <                    int n, c, m;
531 <                    if (tab == null)
532 <                        n = (c = targetCapacity) > 0 ? c : DEFAULT_CAPACITY;
533 <                    else if ((m = tab.length) < MAXIMUM_CAPACITY &&
534 <                             counter.sum() >= (long)threshold)
535 <                        n = m << 1;
536 <                    else
537 <                        break;
538 <                    threshold = n - (n >>> 2) - THRESHOLD_OFFSET;
539 <                    Node[] nextTab = new Node[n];
540 <                    if (tab != null)
541 <                        transfer(tab, nextTab,
542 <                                 new Node(SIGN_BIT, nextTab, null, null));
543 <                    table = nextTab;
544 <                    if (tab == null)
515 >        Node(int hash, Object key, Object val, Node next) {
516 >            this.hash = hash;
517 >            this.key = key;
518 >            this.val = val;
519 >            this.next = next;
520 >        }
521 >
522 >        /** CompareAndSet the hash field */
523 >        final boolean casHash(int cmp, int val) {
524 >            return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
525 >        }
526 >
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 >        /**
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                  }
416            } finally {
417                resizing = 0;
574              }
575          }
576 <        else if (table == null)
577 <            Thread.yield(); // lost initialization race; just spin
578 <        return table;
576 >
577 >        // Unsafe mechanics for casHash
578 >        private static final sun.misc.Unsafe UNSAFE;
579 >        private static final long hashOffset;
580 >
581 >        static {
582 >            try {
583 >                UNSAFE = getUnsafe();
584 >                Class<?> k = Node.class;
585 >                hashOffset = UNSAFE.objectFieldOffset
586 >                    (k.getDeclaredField("hash"));
587 >            } catch (Exception e) {
588 >                throw new Error(e);
589 >            }
590 >        }
591      }
592  
593 +    /* ---------------- TreeBins -------------- */
594 +
595      /**
596 <     * Reclassifies nodes in each bin to new table.  Because we are
597 <     * using power-of-two expansion, the elements from each bin must
598 <     * either stay at same index, or move with a power of two
599 <     * offset. We eliminate unnecessary node creation by catching
600 <     * cases where old nodes can be reused because their next fields
601 <     * won't change.  Statistically, only about one-sixth of them need
602 <     * cloning when a table doubles. The nodes they replace will be
603 <     * garbage collectable as soon as they are no longer referenced by
604 <     * any reader thread that may be in the midst of concurrently
605 <     * traversing table.
596 >     * Nodes for use in TreeBins
597 >     */
598 >    static final class TreeNode extends Node {
599 >        TreeNode parent;  // red-black tree links
600 >        TreeNode left;
601 >        TreeNode right;
602 >        TreeNode prev;    // needed to unlink next upon deletion
603 >        boolean red;
604 >
605 >        TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
606 >            super(hash, key, val, next);
607 >            this.parent = parent;
608 >        }
609 >    }
610 >
611 >    /**
612 >     * A specialized form of red-black tree for use in bins
613 >     * whose size exceeds a threshold.
614       *
615 <     * Transfers are done from the bottom up to preserve iterator
616 <     * traversability. On each step, the old bin is locked,
617 <     * moved/copied, and then replaced with a forwarding node.
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 <    private static final void transfer(Node[] tab, Node[] nextTab, Node fwd) {
655 <        int n = tab.length;
656 <        Node ignore = nextTab[n + n - 1]; // force bounds check
657 <        for (int i = n - 1; i >= 0; --i) {
658 <            for (Node e;;) {
659 <                if ((e = tabAt(tab, i)) != null) {
660 <                    boolean validated = false;
661 <                    synchronized (e) {
662 <                        if (tabAt(tab, i) == e) {
663 <                            validated = true;
664 <                            Node lo = null, hi = null, lastRun = e;
665 <                            int runBit = e.hash & n;
666 <                            for (Node p = e.next; p != null; p = p.next) {
667 <                                int b = p.hash & n;
668 <                                if (b != runBit) {
669 <                                    runBit = b;
670 <                                    lastRun = p;
654 >    static final class TreeBin extends AbstractQueuedSynchronizer {
655 >        private static final long serialVersionUID = 2249069246763182397L;
656 >        transient TreeNode root;  // root of tree
657 >        transient TreeNode first; // head of next-pointer list
658 >
659 >        /* AQS overrides */
660 >        public final boolean isHeldExclusively() { return getState() > 0; }
661 >        public final boolean tryAcquire(int ignore) {
662 >            if (compareAndSetState(0, 1)) {
663 >                setExclusiveOwnerThread(Thread.currentThread());
664 >                return true;
665 >            }
666 >            return false;
667 >        }
668 >        public final boolean tryRelease(int ignore) {
669 >            setExclusiveOwnerThread(null);
670 >            setState(0);
671 >            return true;
672 >        }
673 >        public final int tryAcquireShared(int ignore) {
674 >            for (int c;;) {
675 >                if ((c = getState()) > 0)
676 >                    return -1;
677 >                if (compareAndSetState(c, c -1))
678 >                    return 1;
679 >            }
680 >        }
681 >        public final boolean tryReleaseShared(int ignore) {
682 >            int c;
683 >            do {} while (!compareAndSetState(c = getState(), c + 1));
684 >            return c == -1;
685 >        }
686 >
687 >        /** From CLR */
688 >        private void rotateLeft(TreeNode p) {
689 >            if (p != null) {
690 >                TreeNode r = p.right, pp, rl;
691 >                if ((rl = p.right = r.left) != null)
692 >                    rl.parent = p;
693 >                if ((pp = r.parent = p.parent) == null)
694 >                    root = r;
695 >                else if (pp.left == p)
696 >                    pp.left = r;
697 >                else
698 >                    pp.right = r;
699 >                r.left = p;
700 >                p.parent = r;
701 >            }
702 >        }
703 >
704 >        /** From CLR */
705 >        private void rotateRight(TreeNode p) {
706 >            if (p != null) {
707 >                TreeNode l = p.left, pp, lr;
708 >                if ((lr = p.left = l.right) != null)
709 >                    lr.parent = p;
710 >                if ((pp = l.parent = p.parent) == null)
711 >                    root = l;
712 >                else if (pp.right == p)
713 >                    pp.right = l;
714 >                else
715 >                    pp.left = l;
716 >                l.right = p;
717 >                p.parent = l;
718 >            }
719 >        }
720 >
721 >        /**
722 >         * Returns the TreeNode (or null if not found) for the given key
723 >         * starting at given root.
724 >         */
725 >        @SuppressWarnings("unchecked") final TreeNode getTreeNode
726 >            (int h, Object k, TreeNode p) {
727 >            Class<?> c = k.getClass();
728 >            while (p != null) {
729 >                int dir, ph;  Object pk; Class<?> pc;
730 >                if ((ph = p.hash) == h) {
731 >                    if ((pk = p.key) == k || k.equals(pk))
732 >                        return p;
733 >                    if (c != (pc = pk.getClass()) ||
734 >                        !(k instanceof Comparable) ||
735 >                        (dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
736 >                        dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
737 >                        TreeNode r = null, s = null, pl, pr;
738 >                        if (dir >= 0) {
739 >                            if ((pl = p.left) != null && h <= pl.hash)
740 >                                s = pl;
741 >                        }
742 >                        else if ((pr = p.right) != null && h >= pr.hash)
743 >                            s = pr;
744 >                        if (s != null && (r = getTreeNode(h, k, s)) != null)
745 >                            return r;
746 >                    }
747 >                }
748 >                else
749 >                    dir = (h < ph) ? -1 : 1;
750 >                p = (dir > 0) ? p.right : p.left;
751 >            }
752 >            return null;
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 <                            if (runBit == 0)
854 <                                lo = lastRun;
855 <                            else
856 <                                hi = lastRun;
857 <                            for (Node p = e; p != lastRun; p = p.next) {
858 <                                int ph = p.hash;
859 <                                Object pk = p.key, pv = p.val;
860 <                                if ((ph & n) == 0)
861 <                                    lo = new Node(ph, pk, pv, lo);
862 <                                else
863 <                                    hi = new Node(ph, pk, pv, hi);
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                              }
472                            setTabAt(nextTab, i, lo);
473                            setTabAt(nextTab, i + n, hi);
474                            setTabAt(tab, i, fwd);
875                          }
876                      }
877 <                    if (validated)
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 >            }
950 >            else {
951 >                replacement.parent = pp;
952 >                if (pp == null)
953 >                    root = replacement;
954 >                else if (p == pp.left)
955 >                    pp.left = replacement;
956 >                else
957 >                    pp.right = replacement;
958 >                p.left = p.right = p.parent = null;
959 >            }
960 >            if (!p.red) { // rebalance, from CLR
961 >                TreeNode x = replacement;
962 >                while (x != null) {
963 >                    TreeNode xp, xpl;
964 >                    if (x.red || (xp = x.parent) == null) {
965 >                        x.red = false;
966                          break;
967 +                    }
968 +                    if (x == (xpl = xp.left)) {
969 +                        TreeNode sib = xp.right;
970 +                        if (sib != null && sib.red) {
971 +                            sib.red = false;
972 +                            xp.red = true;
973 +                            rotateLeft(xp);
974 +                            sib = (xp = x.parent) == null ? null : xp.right;
975 +                        }
976 +                        if (sib == null)
977 +                            x = xp;
978 +                        else {
979 +                            TreeNode sl = sib.left, sr = sib.right;
980 +                            if ((sr == null || !sr.red) &&
981 +                                (sl == null || !sl.red)) {
982 +                                sib.red = true;
983 +                                x = xp;
984 +                            }
985 +                            else {
986 +                                if (sr == null || !sr.red) {
987 +                                    if (sl != null)
988 +                                        sl.red = false;
989 +                                    sib.red = true;
990 +                                    rotateRight(sib);
991 +                                    sib = (xp = x.parent) == null ? null : xp.right;
992 +                                }
993 +                                if (sib != null) {
994 +                                    sib.red = (xp == null) ? false : xp.red;
995 +                                    if ((sr = sib.right) != null)
996 +                                        sr.red = false;
997 +                                }
998 +                                if (xp != null) {
999 +                                    xp.red = false;
1000 +                                    rotateLeft(xp);
1001 +                                }
1002 +                                x = root;
1003 +                            }
1004 +                        }
1005 +                    }
1006 +                    else { // symmetric
1007 +                        TreeNode sib = xpl;
1008 +                        if (sib != null && sib.red) {
1009 +                            sib.red = false;
1010 +                            xp.red = true;
1011 +                            rotateRight(xp);
1012 +                            sib = (xp = x.parent) == null ? null : xp.left;
1013 +                        }
1014 +                        if (sib == null)
1015 +                            x = xp;
1016 +                        else {
1017 +                            TreeNode sl = sib.left, sr = sib.right;
1018 +                            if ((sl == null || !sl.red) &&
1019 +                                (sr == null || !sr.red)) {
1020 +                                sib.red = true;
1021 +                                x = xp;
1022 +                            }
1023 +                            else {
1024 +                                if (sl == null || !sl.red) {
1025 +                                    if (sr != null)
1026 +                                        sr.red = false;
1027 +                                    sib.red = true;
1028 +                                    rotateLeft(sib);
1029 +                                    sib = (xp = x.parent) == null ? null : xp.left;
1030 +                                }
1031 +                                if (sib != null) {
1032 +                                    sib.red = (xp == null) ? false : xp.red;
1033 +                                    if ((sl = sib.left) != null)
1034 +                                        sl.red = false;
1035 +                                }
1036 +                                if (xp != null) {
1037 +                                    xp.red = false;
1038 +                                    rotateRight(xp);
1039 +                                }
1040 +                                x = root;
1041 +                            }
1042 +                        }
1043 +                    }
1044                  }
1045 <                else if (casTabAt(tab, i, e, fwd))
1046 <                    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 <    /* ---------------- Internal access and update methods -------------- */
1056 >    /* ---------------- Collision reduction methods -------------- */
1057  
1058      /**
1059 <     * Applies a supplemental hash function to a given hashCode, which
1060 <     * defends against poor quality hash functions.  The result must
1061 <     * be non-negative, and for reasonable performance must have good
1062 <     * avalanche properties; i.e., that each bit of the argument
1063 <     * affects each bit (except sign bit) of the result.
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 <        // Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
1073 <        h ^= h >>> 16;
1074 <        h *= 0x85ebca6b;
1075 <        h ^= h >>> 13;
1076 <        h *= 0xc2b2ae35;
1077 <        return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
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; Object ek, ev; int eh;  // locals to read fields once
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) == h) {
1100 <                    if ((ev = e.val) != null &&
1101 <                        ((ek = e.key) == k || k.equals(ek)))
1102 <                        return ev;
1103 <                }
1104 <                else if (eh < 0) {          // sign bit set
1105 <                    tab = (Node[])e.key;    // bin was moved during resize
517 <                    continue retry;
1099 >                if ((eh = e.hash) == MOVED) {
1100 >                    if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1101 >                        return ((TreeBin)ek).getValue(h, k);
1102 >                    else {                        // restart with new table
1103 >                        tab = (Node[])ek;
1104 >                        continue retry;
1105 >                    }
1106                  }
1107 +                else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1108 +                         ((ek = e.key) == k || k.equals(ek)))
1109 +                    return ev;
1110              }
1111              break;
1112          }
1113          return null;
1114      }
1115  
1116 <    /** Implementation for put and putIfAbsent */
1117 <    private final Object internalPut(Object k, Object v, boolean replace) {
1116 >    /**
1117 >     * Implementation for the four public remove/replace methods:
1118 >     * Replaces node value with v, conditional upon match of cv if
1119 >     * non-null.  If resulting value is null, delete.
1120 >     */
1121 >    private final Object internalReplace(Object k, Object v, Object cv) {
1122          int h = spread(k.hashCode());
1123 <        Object oldVal = null;               // previous value or null if none
1123 >        Object oldVal = null;
1124          for (Node[] tab = table;;) {
1125 <            Node e; int i; Object ek, ev;
1125 >            Node f; int i, fh; Object fk;
1126 >            if (tab == null ||
1127 >                (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1128 >                break;
1129 >            else if ((fh = f.hash) == MOVED) {
1130 >                if ((fk = f.key) instanceof TreeBin) {
1131 >                    TreeBin t = (TreeBin)fk;
1132 >                    boolean validated = false;
1133 >                    boolean deleted = false;
1134 >                    t.acquire(0);
1135 >                    try {
1136 >                        if (tabAt(tab, i) == f) {
1137 >                            validated = true;
1138 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1139 >                            if (p != null) {
1140 >                                Object pv = p.val;
1141 >                                if (cv == null || cv == pv || cv.equals(pv)) {
1142 >                                    oldVal = pv;
1143 >                                    if ((p.val = v) == null) {
1144 >                                        deleted = true;
1145 >                                        t.deleteTreeNode(p);
1146 >                                    }
1147 >                                }
1148 >                            }
1149 >                        }
1150 >                    } finally {
1151 >                        t.release(0);
1152 >                    }
1153 >                    if (validated) {
1154 >                        if (deleted)
1155 >                            counter.add(-1L);
1156 >                        break;
1157 >                    }
1158 >                }
1159 >                else
1160 >                    tab = (Node[])fk;
1161 >            }
1162 >            else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1163 >                break;                          // rules out possible existence
1164 >            else if ((fh & LOCKED) != 0) {
1165 >                checkForResize();               // try resizing if can't get lock
1166 >                f.tryAwaitLock(tab, i);
1167 >            }
1168 >            else if (f.casHash(fh, fh | LOCKED)) {
1169 >                boolean validated = false;
1170 >                boolean deleted = false;
1171 >                try {
1172 >                    if (tabAt(tab, i) == f) {
1173 >                        validated = true;
1174 >                        for (Node e = f, pred = null;;) {
1175 >                            Object ek, ev;
1176 >                            if ((e.hash & HASH_BITS) == h &&
1177 >                                ((ev = e.val) != null) &&
1178 >                                ((ek = e.key) == k || k.equals(ek))) {
1179 >                                if (cv == null || cv == ev || cv.equals(ev)) {
1180 >                                    oldVal = ev;
1181 >                                    if ((e.val = v) == null) {
1182 >                                        deleted = true;
1183 >                                        Node en = e.next;
1184 >                                        if (pred != null)
1185 >                                            pred.next = en;
1186 >                                        else
1187 >                                            setTabAt(tab, i, en);
1188 >                                    }
1189 >                                }
1190 >                                break;
1191 >                            }
1192 >                            pred = e;
1193 >                            if ((e = e.next) == null)
1194 >                                break;
1195 >                        }
1196 >                    }
1197 >                } finally {
1198 >                    if (!f.casHash(fh | LOCKED, fh)) {
1199 >                        f.hash = fh;
1200 >                        synchronized (f) { f.notifyAll(); };
1201 >                    }
1202 >                }
1203 >                if (validated) {
1204 >                    if (deleted)
1205 >                        counter.add(-1L);
1206 >                    break;
1207 >                }
1208 >            }
1209 >        }
1210 >        return oldVal;
1211 >    }
1212 >
1213 >    /*
1214 >     * Internal versions of the six insertion methods, each a
1215 >     * little more complicated than the last. All have
1216 >     * the same basic structure as the first (internalPut):
1217 >     *  1. If table uninitialized, create
1218 >     *  2. If bin empty, try to CAS new node
1219 >     *  3. If bin stale, use new table
1220 >     *  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1221 >     *  5. Lock and validate; if valid, scan and add or update
1222 >     *
1223 >     * The others interweave other checks and/or alternative actions:
1224 >     *  * Plain put checks for and performs resize after insertion.
1225 >     *  * putIfAbsent prescans for mapping without lock (and fails to add
1226 >     *    if present), which also makes pre-emptive resize checks worthwhile.
1227 >     *  * computeIfAbsent extends form used in putIfAbsent with additional
1228 >     *    mechanics to deal with, calls, potential exceptions and null
1229 >     *    returns from function call.
1230 >     *  * compute uses the same function-call mechanics, but without
1231 >     *    the prescans
1232 >     *  * merge acts as putIfAbsent in the absent case, but invokes the
1233 >     *    update function if present
1234 >     *  * putAll attempts to pre-allocate enough table space
1235 >     *    and more lazily performs count updates and checks.
1236 >     *
1237 >     * Someday when details settle down a bit more, it might be worth
1238 >     * some factoring to reduce sprawl.
1239 >     */
1240 >
1241 >    /** Implementation for put */
1242 >    private final Object internalPut(Object k, Object v) {
1243 >        int h = spread(k.hashCode());
1244 >        int count = 0;
1245 >        for (Node[] tab = table;;) {
1246 >            int i; Node f; int fh; Object fk;
1247              if (tab == null)
1248 <                tab = growTable();
1249 <            else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1248 >                tab = initTable();
1249 >            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1250                  if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1251                      break;                   // no lock when adding to empty bin
1252              }
1253 <            else if (e.hash < 0)             // resized -- restart with new table
1254 <                tab = (Node[])e.key;
1255 <            else if (!replace && e.hash == h && (ev = e.val) != null &&
1256 <                     ((ek = e.key) == k || k.equals(ek))) {
1257 <                if (tabAt(tab, i) == e) {    // inspect and validate 1st node
1258 <                    oldVal = ev;             // without lock for putIfAbsent
1259 <                    break;
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 {
1280 <                boolean validated = false;
1281 <                boolean checkSize = false;
1282 <                synchronized (e) {           // lock the 1st node of bin list
1283 <                    if (tabAt(tab, i) == e) {
1284 <                        validated = true;    // retry if 1st already deleted
1285 <                        for (Node first = e;;) {
1286 <                            if (e.hash == h &&
1287 <                                ((ek = e.key) == k || k.equals(ek)) &&
1288 <                                (ev = e.val) != null) {
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 <                                if (replace)
558 <                                    e.val = v;
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 (last != first || tab.length <= 64)
1301 <                                    checkSize = true;
1300 >                                if (count >= TREE_THRESHOLD)
1301 >                                    replaceWithTreeBin(tab, i, k);
1302                                  break;
1303                              }
1304                          }
1305                      }
1306 +                } finally {                  // unlock and signal if needed
1307 +                    if (!f.casHash(fh | LOCKED, fh)) {
1308 +                        f.hash = fh;
1309 +                        synchronized (f) { f.notifyAll(); };
1310 +                    }
1311                  }
1312 <                if (validated) {
1313 <                    if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1314 <                        resizing == 0 && counter.sum() >= (long)threshold)
1315 <                        growTable();
1312 >                if (count != 0) {
1313 >                    if (oldVal != null)
1314 >                        return oldVal;
1315 >                    if (tab.length <= 64)
1316 >                        count = 2;
1317                      break;
1318                  }
1319              }
1320          }
1321 <        if (oldVal == null)
1322 <            counter.increment();             // update counter outside of locks
1323 <        return oldVal;
1321 >        counter.add(1L);
1322 >        if (count > 1)
1323 >            checkForResize();
1324 >        return null;
1325      }
1326  
1327 <    /**
1328 <     * Implementation for the four public remove/replace methods:
586 <     * Replaces node value with v, conditional upon match of cv if
587 <     * non-null.  If resulting value is null, delete.
588 <     */
589 <    private final Object internalReplace(Object k, Object v, Object cv) {
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 <            Node e; int i;
1333 <            if (tab == null ||
1334 <                (e = tabAt(tab, i = (tab.length - 1) & h)) == null)
1335 <                return null;
1336 <            else if (e.hash < 0)
1337 <                tab = (Node[])e.key;
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 <                Object oldVal = null;
1368 <                boolean validated = false;
1369 <                boolean deleted = false;
1370 <                synchronized (e) {
1371 <                    if (tabAt(tab, i) == e) {
1372 <                        validated = true;
1373 <                        Node pred = null;
1374 <                        do {
1375 <                            Object ek, ev;
1376 <                            if (e.hash == h &&
1377 <                                ((ek = e.key) == k || k.equals(ek)) &&
1378 <                                ((ev = e.val) != null)) {
1379 <                                if (cv == null || cv == ev || cv.equals(ev)) {
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 <                                    if ((e.val = v) == null) {
1396 <                                        deleted = true;
1397 <                                        Node en = e.next;
1398 <                                        if (pred != null)
1399 <                                            pred.next = en;
1400 <                                        else
1401 <                                            setTabAt(tab, i, en);
1402 <                                    }
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                                  }
622                                break;
1404                              }
1405 <                        } while ((e = (pred = e).next) != null);
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                      }
626                }
627                if (validated) {
628                    if (deleted)
629                        counter.decrement();
630                    return oldVal;
1419                  }
1420              }
1421          }
1422 +        counter.add(1L);
1423 +        if (count > 1)
1424 +            checkForResize();
1425 +        return null;
1426      }
1427  
1428 <    /** Implementation for computeIfAbsent and compute. Like put, but messier. */
1429 <    @SuppressWarnings("unchecked")
1430 <    private final V internalCompute(K k,
639 <                                    MappingFunction<? super K, ? extends V> f,
640 <                                    boolean replace) {
1428 >    /** Implementation for computeIfAbsent */
1429 >    private final Object internalComputeIfAbsent(K k,
1430 >                                                 Fun<? super K, ?> mf) {
1431          int h = spread(k.hashCode());
1432 <        V val = null;
1433 <        boolean added = false;
1434 <        Node[] tab = table;
1435 <        outer:for (;;) {
646 <            Node e; int i; Object ek, ev;
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 = growTable();
1438 <            else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1439 <                Node node = new Node(h, k, null, null);
1440 <                boolean validated = false;
1441 <                synchronized (node) {  // must lock while computing value
1442 <                    if (casTabAt(tab, i, null, node)) {
1443 <                        validated = true;
1444 <                        try {
1445 <                            val = f.map(k);
1446 <                            if (val != null) {
1447 <                                node.val = val;
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                              }
661                        } finally {
662                            if (!added)
663                                setTabAt(tab, i, null);
1473                          }
1474 +                    } finally {
1475 +                        t.release(0);
1476 +                    }
1477 +                    if (count != 0) {
1478 +                        if (!added)
1479 +                            return val;
1480 +                        break;
1481                      }
1482                  }
1483 <                if (validated)
1484 <                    break;
1483 >                else
1484 >                    tab = (Node[])fk;
1485              }
1486 <            else if (e.hash < 0)
1487 <                tab = (Node[])e.key;
1488 <            else if (!replace && e.hash == h && (ev = e.val) != null &&
1489 <                     ((ek = e.key) == k || k.equals(ek))) {
1490 <                if (tabAt(tab, i) == e) {
1491 <                    val = (V)ev;
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 (Thread.holdsLock(e))
1591 <                throw new IllegalStateException("Recursive map computation");
1592 <            else {
1593 <                boolean validated = false;
1594 <                boolean checkSize = false;
1595 <                synchronized (e) {
1596 <                    if (tabAt(tab, i) == e) {
1597 <                        validated = true;
1598 <                        for (Node first = e;;) {
1599 <                            if (e.hash == h &&
1600 <                                ((ek = e.key) == k || k.equals(ek)) &&
1601 <                                ((ev = e.val) != null)) {
1602 <                                Object fv;
1603 <                                if (replace && (fv = f.map(k)) != null)
1604 <                                    ev = e.val = fv;
1605 <                                val = (V)ev;
1590 >            else if ((fh = f.hash) == MOVED) {
1591 >                if ((fk = f.key) instanceof TreeBin) {
1592 >                    TreeBin t = (TreeBin)fk;
1593 >                    t.acquire(0);
1594 >                    try {
1595 >                        if (tabAt(tab, i) == f) {
1596 >                            count = 1;
1597 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1598 >                            Object pv = (p == null) ? null : p.val;
1599 >                            if ((val = mf.apply(k, (V)pv)) != null) {
1600 >                                if (p != null)
1601 >                                    p.val = val;
1602 >                                else {
1603 >                                    count = 2;
1604 >                                    delta = 1;
1605 >                                    t.putTreeNode(h, k, val);
1606 >                                }
1607 >                            }
1608 >                            else if (p != null) {
1609 >                                delta = -1;
1610 >                                t.deleteTreeNode(p);
1611 >                            }
1612 >                        }
1613 >                    } finally {
1614 >                        t.release(0);
1615 >                    }
1616 >                    if (count != 0)
1617 >                        break;
1618 >                }
1619 >                else
1620 >                    tab = (Node[])fk;
1621 >            }
1622 >            else if ((fh & LOCKED) != 0) {
1623 >                checkForResize();
1624 >                f.tryAwaitLock(tab, i);
1625 >            }
1626 >            else if (f.casHash(fh, fh | LOCKED)) {
1627 >                try {
1628 >                    if (tabAt(tab, i) == f) {
1629 >                        count = 1;
1630 >                        for (Node e = f, pred = null;; ++count) {
1631 >                            Object ek, ev;
1632 >                            if ((e.hash & HASH_BITS) == h &&
1633 >                                (ev = e.val) != null &&
1634 >                                ((ek = e.key) == k || k.equals(ek))) {
1635 >                                val = mf.apply(k, (V)ev);
1636 >                                if (val != null)
1637 >                                    e.val = val;
1638 >                                else {
1639 >                                    delta = -1;
1640 >                                    Node en = e.next;
1641 >                                    if (pred != null)
1642 >                                        pred.next = en;
1643 >                                    else
1644 >                                        setTabAt(tab, i, en);
1645 >                                }
1646                                  break;
1647                              }
1648 <                            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() >= (long)threshold)
713 <                        growTable();
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 +    /** Implementation for merge */
1682 +    @SuppressWarnings("unchecked") private final Object internalMerge
1683 +        (K k, V v, BiFun<? super V, ? super V, ? extends V> mf) {
1684 +        int h = spread(k.hashCode());
1685 +        Object val = null;
1686 +        int delta = 0;
1687 +        int count = 0;
1688 +        for (Node[] tab = table;;) {
1689 +            int i; Node f; int fh; Object fk, fv;
1690 +            if (tab == null)
1691 +                tab = initTable();
1692 +            else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1693 +                if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1694 +                    delta = 1;
1695 +                    val = v;
1696 +                    break;
1697 +                }
1698 +            }
1699 +            else if ((fh = f.hash) == MOVED) {
1700 +                if ((fk = f.key) instanceof TreeBin) {
1701 +                    TreeBin t = (TreeBin)fk;
1702 +                    t.acquire(0);
1703 +                    try {
1704 +                        if (tabAt(tab, i) == f) {
1705 +                            count = 1;
1706 +                            TreeNode p = t.getTreeNode(h, k, t.root);
1707 +                            val = (p == null) ? v : mf.apply((V)p.val, v);
1708 +                            if (val != null) {
1709 +                                if (p != null)
1710 +                                    p.val = val;
1711 +                                else {
1712 +                                    count = 2;
1713 +                                    delta = 1;
1714 +                                    t.putTreeNode(h, k, val);
1715 +                                }
1716 +                            }
1717 +                            else if (p != null) {
1718 +                                delta = -1;
1719 +                                t.deleteTreeNode(p);
1720 +                            }
1721 +                        }
1722 +                    } finally {
1723 +                        t.release(0);
1724 +                    }
1725 +                    if (count != 0)
1726 +                        break;
1727 +                }
1728 +                else
1729 +                    tab = (Node[])fk;
1730 +            }
1731 +            else if ((fh & LOCKED) != 0) {
1732 +                checkForResize();
1733 +                f.tryAwaitLock(tab, i);
1734 +            }
1735 +            else if (f.casHash(fh, fh | LOCKED)) {
1736 +                try {
1737 +                    if (tabAt(tab, i) == f) {
1738 +                        count = 1;
1739 +                        for (Node e = f, pred = null;; ++count) {
1740 +                            Object ek, ev;
1741 +                            if ((e.hash & HASH_BITS) == h &&
1742 +                                (ev = e.val) != null &&
1743 +                                ((ek = e.key) == k || k.equals(ek))) {
1744 +                                val = mf.apply(v, (V)ev);
1745 +                                if (val != null)
1746 +                                    e.val = val;
1747 +                                else {
1748 +                                    delta = -1;
1749 +                                    Node en = e.next;
1750 +                                    if (pred != null)
1751 +                                        pred.next = en;
1752 +                                    else
1753 +                                        setTabAt(tab, i, en);
1754 +                                }
1755 +                                break;
1756 +                            }
1757 +                            pred = e;
1758 +                            if ((e = e.next) == null) {
1759 +                                val = v;
1760 +                                pred.next = new Node(h, k, val, null);
1761 +                                delta = 1;
1762 +                                if (count >= TREE_THRESHOLD)
1763 +                                    replaceWithTreeBin(tab, i, k);
1764 +                                break;
1765 +                            }
1766 +                        }
1767 +                    }
1768 +                } finally {
1769 +                    if (!f.casHash(fh | LOCKED, fh)) {
1770 +                        f.hash = fh;
1771 +                        synchronized (f) { f.notifyAll(); };
1772 +                    }
1773 +                }
1774 +                if (count != 0) {
1775 +                    if (tab.length <= 64)
1776 +                        count = 2;
1777 +                    break;
1778 +                }
1779 +            }
1780 +        }
1781 +        if (delta != 0) {
1782 +            counter.add((long)delta);
1783 +            if (count > 1)
1784 +                checkForResize();
1785 +        }
1786 +        return val;
1787 +    }
1788 +
1789 +    /** Implementation for putAll */
1790 +    private final void internalPutAll(Map<?, ?> m) {
1791 +        tryPresize(m.size());
1792 +        long delta = 0L;     // number of uncommitted additions
1793 +        boolean npe = false; // to throw exception on exit for nulls
1794 +        try {                // to clean up counts on other exceptions
1795 +            for (Map.Entry<?, ?> entry : m.entrySet()) {
1796 +                Object k, v;
1797 +                if (entry == null || (k = entry.getKey()) == null ||
1798 +                    (v = entry.getValue()) == null) {
1799 +                    npe = true;
1800 +                    break;
1801 +                }
1802 +                int h = spread(k.hashCode());
1803 +                for (Node[] tab = table;;) {
1804 +                    int i; Node f; int fh; Object fk;
1805 +                    if (tab == null)
1806 +                        tab = initTable();
1807 +                    else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1808 +                        if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1809 +                            ++delta;
1810 +                            break;
1811 +                        }
1812 +                    }
1813 +                    else if ((fh = f.hash) == MOVED) {
1814 +                        if ((fk = f.key) instanceof TreeBin) {
1815 +                            TreeBin t = (TreeBin)fk;
1816 +                            boolean validated = false;
1817 +                            t.acquire(0);
1818 +                            try {
1819 +                                if (tabAt(tab, i) == f) {
1820 +                                    validated = true;
1821 +                                    TreeNode p = t.getTreeNode(h, k, t.root);
1822 +                                    if (p != null)
1823 +                                        p.val = v;
1824 +                                    else {
1825 +                                        t.putTreeNode(h, k, v);
1826 +                                        ++delta;
1827 +                                    }
1828 +                                }
1829 +                            } finally {
1830 +                                t.release(0);
1831 +                            }
1832 +                            if (validated)
1833 +                                break;
1834 +                        }
1835 +                        else
1836 +                            tab = (Node[])fk;
1837 +                    }
1838 +                    else if ((fh & LOCKED) != 0) {
1839 +                        counter.add(delta);
1840 +                        delta = 0L;
1841 +                        checkForResize();
1842 +                        f.tryAwaitLock(tab, i);
1843 +                    }
1844 +                    else if (f.casHash(fh, fh | LOCKED)) {
1845 +                        int count = 0;
1846 +                        try {
1847 +                            if (tabAt(tab, i) == f) {
1848 +                                count = 1;
1849 +                                for (Node e = f;; ++count) {
1850 +                                    Object ek, ev;
1851 +                                    if ((e.hash & HASH_BITS) == h &&
1852 +                                        (ev = e.val) != null &&
1853 +                                        ((ek = e.key) == k || k.equals(ek))) {
1854 +                                        e.val = v;
1855 +                                        break;
1856 +                                    }
1857 +                                    Node last = e;
1858 +                                    if ((e = e.next) == null) {
1859 +                                        ++delta;
1860 +                                        last.next = new Node(h, k, v, null);
1861 +                                        if (count >= TREE_THRESHOLD)
1862 +                                            replaceWithTreeBin(tab, i, k);
1863 +                                        break;
1864 +                                    }
1865 +                                }
1866 +                            }
1867 +                        } finally {
1868 +                            if (!f.casHash(fh | LOCKED, fh)) {
1869 +                                f.hash = fh;
1870 +                                synchronized (f) { f.notifyAll(); };
1871 +                            }
1872 +                        }
1873 +                        if (count != 0) {
1874 +                            if (count > 1) {
1875 +                                counter.add(delta);
1876 +                                delta = 0L;
1877 +                                checkForResize();
1878 +                            }
1879 +                            break;
1880 +                        }
1881 +                    }
1882 +                }
1883 +            }
1884 +        } finally {
1885 +            if (delta != 0)
1886 +                counter.add(delta);
1887 +        }
1888 +        if (npe)
1889 +            throw new NullPointerException();
1890 +    }
1891 +
1892 +    /* ---------------- Table Initialization and Resizing -------------- */
1893 +
1894 +    /**
1895 +     * Returns a power of two table size for the given desired capacity.
1896 +     * See Hackers Delight, sec 3.2
1897 +     */
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 +                } finally {
1924 +                    sizeCtl = sc;
1925 +                }
1926 +                break;
1927 +            }
1928 +        }
1929 +        return tab;
1930 +    }
1931 +
1932 +    /**
1933 +     * If table is too small and not already resizing, creates next
1934 +     * table and transfers bins.  Rechecks occupancy after a transfer
1935 +     * to see if another resize is already needed because resizings
1936 +     * are lagging additions.
1937 +     */
1938 +    private final void checkForResize() {
1939 +        Node[] tab; int n, sc;
1940 +        while ((tab = table) != null &&
1941 +               (n = tab.length) < MAXIMUM_CAPACITY &&
1942 +               (sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1943 +               UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1944 +            try {
1945 +                if (tab == table) {
1946 +                    table = rebuild(tab);
1947 +                    sc = (n << 1) - (n >>> 1);
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 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 >                try {              // split to lo and hi lists; copying as needed
2052 >                    if (tabAt(tab, i) == f) {
2053 >                        validated = true;
2054 >                        splitBin(nextTab, i, f);
2055 >                        setTabAt(tab, i, fwd);
2056 >                    }
2057 >                } finally {
2058 >                    if (!f.casHash(fh | LOCKED, fh)) {
2059 >                        f.hash = fh;
2060 >                        synchronized (f) { f.notifyAll(); };
2061 >                    }
2062 >                }
2063 >                if (!validated)
2064 >                    continue;
2065 >            }
2066 >            else {
2067 >                if (buffer == null) // initialize buffer for revisits
2068 >                    buffer = new int[TRANSFER_BUFFER_SIZE];
2069 >                if (bin < 0 && bufferIndex > 0) {
2070 >                    int j = buffer[--bufferIndex];
2071 >                    buffer[bufferIndex] = i;
2072 >                    i = j;         // swap with another bin
2073 >                    continue;
2074 >                }
2075 >                if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
2076 >                    f.tryAwaitLock(tab, i);
2077 >                    continue;      // no other options -- block
2078 >                }
2079 >                if (rev == null)   // initialize reverse-forwarder
2080 >                    rev = new Node(MOVED, tab, null, null);
2081 >                if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
2082 >                    continue;      // recheck before adding to list
2083 >                buffer[nbuffered++] = i;
2084 >                setTabAt(nextTab, i, rev);     // install place-holders
2085 >                setTabAt(nextTab, i + n, rev);
2086 >            }
2087 >
2088 >            if (bin > 0)
2089 >                i = --bin;
2090 >            else if (buffer != null && nbuffered > 0) {
2091 >                bin = -1;
2092 >                i = buffer[bufferIndex = --nbuffered];
2093 >            }
2094 >            else
2095 >                return nextTab;
2096 >        }
2097 >    }
2098 >
2099 >    /**
2100 >     * Splits a normal bin with list headed by e into lo and hi parts;
2101 >     * installs in given table.
2102 >     */
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 >    /**
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 >                ++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 >    /**
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 <            Node e = tabAt(tab, i);
2179 <            if (e == null)
2178 >            int fh; Object fk;
2179 >            Node f = tabAt(tab, i);
2180 >            if (f == null)
2181                  ++i;
2182 <            else if (e.hash < 0)
2183 <                tab = (Node[])e.key;
2184 <            else {
2185 <                boolean validated = false;
2186 <                synchronized (e) {
2187 <                    if (tabAt(tab, i) == e) {
2188 <                        validated = true;
2189 <                        Node en;
2190 <                        do {
2191 <                            en = e.next;
2192 <                            if (e.val != null) { // currently always true
2182 >            else if ((fh = f.hash) == MOVED) {
2183 >                if ((fk = f.key) instanceof TreeBin) {
2184 >                    TreeBin t = (TreeBin)fk;
2185 >                    t.acquire(0);
2186 >                    try {
2187 >                        if (tabAt(tab, i) == f) {
2188 >                            for (Node p = t.first; p != null; p = p.next) {
2189 >                                if (p.val != null) { // (currently always true)
2190 >                                    p.val = null;
2191 >                                    --delta;
2192 >                                }
2193 >                            }
2194 >                            t.first = null;
2195 >                            t.root = null;
2196 >                            ++i;
2197 >                        }
2198 >                    } finally {
2199 >                        t.release(0);
2200 >                    }
2201 >                }
2202 >                else
2203 >                    tab = (Node[])fk;
2204 >            }
2205 >            else if ((fh & LOCKED) != 0) {
2206 >                counter.add(delta); // opportunistically update count
2207 >                delta = 0L;
2208 >                f.tryAwaitLock(tab, i);
2209 >            }
2210 >            else if (f.casHash(fh, fh | LOCKED)) {
2211 >                try {
2212 >                    if (tabAt(tab, i) == f) {
2213 >                        for (Node e = f; e != null; e = e.next) {
2214 >                            if (e.val != null) {  // (currently always true)
2215                                  e.val = null;
2216                                  --delta;
2217                              }
2218 <                        } while ((e = en) != null);
2218 >                        }
2219                          setTabAt(tab, i, null);
2220 +                        ++i;
2221 +                    }
2222 +                } finally {
2223 +                    if (!f.casHash(fh | LOCKED, fh)) {
2224 +                        f.hash = fh;
2225 +                        synchronized (f) { f.notifyAll(); };
2226                      }
2227                  }
752                if (validated)
753                    ++i;
2228              }
2229          }
2230 <        counter.add(delta);
2230 >        if (delta != 0)
2231 >            counter.add(delta);
2232      }
2233  
2234      /* ----------------Table Traversal -------------- */
2235  
2236      /**
2237       * Encapsulates traversal for methods such as containsValue; also
2238 <     * serves as a base class for other iterators.
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 nonnull user value). Because val fields can
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.next != null) { process(nextKey); it.advance(); }}
2249 >     * {@code while (it.advance() != null) { process(it.nextKey); }}
2250       *
2251 <     * Exported iterators (subclasses of ViewIterator) extract key,
2252 <     * value, or key-value pairs as return values of Iterator.next(),
2253 <     * and encapsulate the it.next check as hasNext();
2254 <     *
2255 <     * The iterator visits each valid node that was reachable upon
2256 <     * iterator construction once. It might miss some that were added
2257 <     * to a bin after the bin was visited, which is OK wrt consistency
2258 <     * guarantees. Maintaining this property in the face of possible
2259 <     * ongoing resizes requires a fair amount of bookkeeping state
2260 <     * that is difficult to optimize away amidst volatile accesses.
2261 <     * Even so, traversal maintains reasonable throughput.
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
# Line 793 | Line 2270 | public class ConcurrentHashMapV8<K, V>
2270       * across threads, iteration terminates if a bounds checks fails
2271       * for a table read.
2272       *
2273 <     * The range-based constructor enables creation of parallel
2274 <     * range-splitting traversals. (Not yet implemented.)
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 <    static class InternalIterator {
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
# Line 804 | Line 2286 | public class ConcurrentHashMapV8<K, V>
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 <        final int baseLimit; // index bound for 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 <        InternalIterator(Node[] tab) {
2294 <            this.tab = tab;
2293 >        Traverser(ConcurrentHashMapV8<K, V> map) {
2294 >            this.tab = (this.map = map).table;
2295              baseLimit = baseSize = (tab == null) ? 0 : tab.length;
814            index = baseIndex = 0;
815            next = null;
816            advance();
817        }
818
819        /** Creates iterator for the given range of the table */
820        InternalIterator(Node[] tab, int lo, int hi) {
821            this.tab = tab;
822            baseSize = (tab == null) ? 0 : tab.length;
823            baseLimit = (hi <= baseSize) ? hi : baseSize;
824            index = baseIndex = lo;
825            next = null;
826            advance();
2296          }
2297  
2298 <        /** Advances next. See above for explanation. */
2299 <        final void advance() {
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 >        /**
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)                   // pass used or skipped node
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;       // checks must use locals
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 < 0)
2323 <                        tab = (Node[])e.key;     // restarts due to null val
2324 <                    else                         // visit upper slots if present
2325 <                        index = (i += baseSize) < n ? i : (baseIndex = b + 1);
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 ((nextVal = e.val) == null); // skip deleted or special nodes
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 (nextVal == null && last == null)
2340 +                advance();
2341 +            Node e = last;
2342 +            if (e == null)
2343 +                throw new IllegalStateException();
2344 +            last = null;
2345 +            map.remove(e.key);
2346 +        }
2347 +
2348 +        public final boolean hasNext() {
2349 +            return nextVal != null || advance() != null;
2350 +        }
2351 +
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 default initial table size (16),
2361 >     * Creates a new, empty map with the default initial table size (16).
2362       */
2363      public ConcurrentHashMapV8() {
2364          this.counter = new LongAdder();
858        this.targetCapacity = DEFAULT_CAPACITY;
2365      }
2366  
2367      /**
# Line 875 | Line 2381 | public class ConcurrentHashMapV8<K, V>
2381                     MAXIMUM_CAPACITY :
2382                     tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2383          this.counter = new LongAdder();
2384 <        this.targetCapacity = cap;
2384 >        this.sizeCtl = cap;
2385      }
2386  
2387      /**
# Line 885 | Line 2391 | public class ConcurrentHashMapV8<K, V>
2391       */
2392      public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2393          this.counter = new LongAdder();
2394 <        this.targetCapacity = DEFAULT_CAPACITY;
2395 <        putAll(m);
2394 >        this.sizeCtl = DEFAULT_CAPACITY;
2395 >        internalPutAll(m);
2396      }
2397  
2398      /**
# Line 901 | Line 2407 | public class ConcurrentHashMapV8<K, V>
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(int initialCapacity, float loadFactor) {
2414          this(initialCapacity, loadFactor, 1);
# Line 931 | Line 2439 | public class ConcurrentHashMapV8<K, V>
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));
2442 >        int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2443 >            MAXIMUM_CAPACITY : tableSizeFor((int)size);
2444          this.counter = new LongAdder();
2445 <        this.targetCapacity = cap;
2445 >        this.sizeCtl = cap;
2446      }
2447  
2448      /**
# Line 955 | Line 2463 | public class ConcurrentHashMapV8<K, V>
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 +    /**
2480       * Returns the value to which the specified key is mapped,
2481       * or {@code null} if this map contains no mapping for the key.
2482       *
# Line 965 | Line 2487 | public class ConcurrentHashMapV8<K, V>
2487       *
2488       * @throws NullPointerException if the specified key is null
2489       */
2490 <    @SuppressWarnings("unchecked")
969 <    public V get(Object key) {
2490 >    @SuppressWarnings("unchecked") public V get(Object key) {
2491          if (key == null)
2492              throw new NullPointerException();
2493          return (V)internalGet(key);
# Line 1001 | Line 2522 | public class ConcurrentHashMapV8<K, V>
2522          if (value == null)
2523              throw new NullPointerException();
2524          Object v;
2525 <        InternalIterator it = new InternalIterator(table);
2526 <        while (it.next != null) {
2527 <            if ((v = it.nextVal) == value || value.equals(v))
2525 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2526 >        while ((v = it.advance()) != null) {
2527 >            if (v == value || value.equals(v))
2528                  return true;
1008            it.advance();
2529          }
2530          return false;
2531      }
# Line 1042 | Line 2562 | public class ConcurrentHashMapV8<K, V>
2562       *         {@code null} if there was no mapping for {@code key}
2563       * @throws NullPointerException if the specified key or value is null
2564       */
2565 <    @SuppressWarnings("unchecked")
1046 <    public V put(K key, V value) {
2565 >    @SuppressWarnings("unchecked") public V put(K key, V value) {
2566          if (key == null || value == null)
2567              throw new NullPointerException();
2568 <        return (V)internalPut(key, value, true);
2568 >        return (V)internalPut(key, value);
2569      }
2570  
2571      /**
# Line 1056 | Line 2575 | public class ConcurrentHashMapV8<K, V>
2575       *         or {@code null} if there was no mapping for the key
2576       * @throws NullPointerException if the specified key or value is null
2577       */
2578 <    @SuppressWarnings("unchecked")
1060 <    public V putIfAbsent(K key, V value) {
2578 >    @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
2579          if (key == null || value == null)
2580              throw new NullPointerException();
2581 <        return (V)internalPut(key, value, false);
2581 >        return (V)internalPutIfAbsent(key, value);
2582      }
2583  
2584      /**
# Line 1071 | Line 2589 | public class ConcurrentHashMapV8<K, V>
2589       * @param m mappings to be stored in this map
2590       */
2591      public void putAll(Map<? extends K, ? extends V> m) {
2592 <        if (m == null)
1075 <            throw new NullPointerException();
1076 <        /*
1077 <         * If uninitialized, try to adjust targetCapacity to
1078 <         * accommodate the given number of elements.
1079 <         */
1080 <        if (table == null) {
1081 <            int size = m.size();
1082 <            int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1083 <                tableSizeFor(size + (size >>> 1) + 1);
1084 <            if (cap > targetCapacity)
1085 <                targetCapacity = cap;
1086 <        }
1087 <        for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1088 <            put(e.getKey(), e.getValue());
2592 >        internalPutAll(m);
2593      }
2594  
2595      /**
2596       * If the specified key is not already associated with a value,
2597 <     * computes its value using the given mappingFunction, and if
2598 <     * non-null, enters it into the map.  This is equivalent to
2599 <     *  <pre> {@code
2597 >     * computes its value using the given mappingFunction and enters
2598 >     * it into the map unless null.  This is equivalent to
2599 >     * <pre> {@code
2600       * if (map.containsKey(key))
2601       *   return map.get(key);
2602 <     * value = mappingFunction.map(key);
2602 >     * value = mappingFunction.apply(key);
2603       * if (value != null)
2604       *   map.put(key, value);
2605       * return value;}</pre>
2606       *
2607 <     * except that the action is performed atomically.  Some attempted
2608 <     * update operations on this map by other threads may be blocked
2609 <     * while computation is in progress, so the computation should be
2610 <     * short and simple, and must not attempt to update any other
2611 <     * mappings of this Map. The most appropriate usage is to
2607 >     * except that the action is performed atomically.  If the
2608 >     * function returns {@code null} no mapping is recorded. If the
2609 >     * function itself throws an (unchecked) exception, the exception
2610 >     * is rethrown to its caller, and no mapping is recorded.  Some
2611 >     * attempted update operations on this map by other threads may be
2612 >     * blocked while computation is in progress, so the computation
2613 >     * should be short and simple, and must not attempt to update any
2614 >     * other mappings of this Map. The most appropriate usage is to
2615       * construct a new object serving as an initial mapped value, or
2616       * memoized result, as in:
2617 +     *
2618       *  <pre> {@code
2619 <     * map.computeIfAbsent(key, new MappingFunction<K, V>() {
2619 >     * map.computeIfAbsent(key, new Fun<K, V>() {
2620       *   public V map(K k) { return new Value(f(k)); }});}</pre>
2621       *
2622       * @param key key with which the specified value is to be associated
2623       * @param mappingFunction the function to compute a value
2624       * @return the current (existing or computed) value associated with
2625 <     *         the specified key, or {@code null} if the computation
1118 <     *         returned {@code null}
2625 >     *         the specified key, or null if the computed value is null.
2626       * @throws NullPointerException if the specified key or mappingFunction
2627       *         is null
2628       * @throws IllegalStateException if the computation detectably
# Line 1124 | Line 2631 | public class ConcurrentHashMapV8<K, V>
2631       * @throws RuntimeException or Error if the mappingFunction does so,
2632       *         in which case the mapping is left unestablished
2633       */
2634 <    public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2634 >    @SuppressWarnings("unchecked") public V computeIfAbsent
2635 >        (K key, Fun<? super K, ? extends V> mappingFunction) {
2636          if (key == null || mappingFunction == null)
2637              throw new NullPointerException();
2638 <        return internalCompute(key, mappingFunction, false);
2638 >        return (V)internalComputeIfAbsent(key, mappingFunction);
2639      }
2640  
2641      /**
2642 <     * Computes the value associated with the given key using the given
2643 <     * mappingFunction, and if non-null, enters it into the map.  This
1136 <     * is equivalent to
2642 >     * If the given key is present, computes a new mapping value given a key and
2643 >     * its current mapped value. This is equivalent to
2644       *  <pre> {@code
2645 <     * value = mappingFunction.map(key);
2646 <     * if (value != null)
2647 <     *   map.put(key, value);
2648 <     * else
2649 <     *   value = map.get(key);
2650 <     * return value;}</pre>
2645 >     *   if (map.containsKey(key)) {
2646 >     *     value = remappingFunction.apply(key, map.get(key));
2647 >     *     if (value != null)
2648 >     *       map.put(key, value);
2649 >     *     else
2650 >     *       map.remove(key);
2651 >     *   }
2652 >     * }</pre>
2653 >     *
2654 >     * except that the action is performed atomically.  If the
2655 >     * function returns {@code null}, the mapping is removed.  If the
2656 >     * function itself throws an (unchecked) exception, the exception
2657 >     * is rethrown to its caller, and the current mapping is left
2658 >     * unchanged.  Some attempted update operations on this map by
2659 >     * other threads may be blocked while computation is in progress,
2660 >     * so the computation should be short and simple, and must not
2661 >     * attempt to update any other mappings of this Map. For example,
2662 >     * to either create or append new messages to a value mapping:
2663       *
2664 <     * except that the action is performed atomically.  Some attempted
2665 <     * update operations on this map by other threads may be blocked
2666 <     * while computation is in progress, so the computation should be
2667 <     * short and simple, and must not attempt to update any other
2668 <     * mappings of this Map.
2664 >     * @param key key with which the specified value is to be associated
2665 >     * @param remappingFunction the function to compute a value
2666 >     * @return the new value associated with the specified key, or null if none
2667 >     * @throws NullPointerException if the specified key or remappingFunction
2668 >     *         is null
2669 >     * @throws IllegalStateException if the computation detectably
2670 >     *         attempts a recursive update to this map that would
2671 >     *         otherwise never complete
2672 >     * @throws RuntimeException or Error if the remappingFunction does so,
2673 >     *         in which case the mapping is unchanged
2674 >     */
2675 >    @SuppressWarnings("unchecked") public V computeIfPresent
2676 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2677 >        if (key == null || remappingFunction == null)
2678 >            throw new NullPointerException();
2679 >        return (V)internalCompute(key, true, remappingFunction);
2680 >    }
2681 >
2682 >    /**
2683 >     * Computes a new mapping value given a key and
2684 >     * its current mapped value (or {@code null} if there is no current
2685 >     * mapping). This is equivalent to
2686 >     *  <pre> {@code
2687 >     *   value = remappingFunction.apply(key, map.get(key));
2688 >     *   if (value != null)
2689 >     *     map.put(key, value);
2690 >     *   else
2691 >     *     map.remove(key);
2692 >     * }</pre>
2693 >     *
2694 >     * except that the action is performed atomically.  If the
2695 >     * function returns {@code null}, the mapping is removed.  If the
2696 >     * function itself throws an (unchecked) exception, the exception
2697 >     * is rethrown to its caller, and the current mapping is left
2698 >     * unchanged.  Some attempted update operations on this map by
2699 >     * other threads may be blocked while computation is in progress,
2700 >     * so the computation should be short and simple, and must not
2701 >     * attempt to update any other mappings of this Map. For example,
2702 >     * to either create or append new messages to a value mapping:
2703 >     *
2704 >     * <pre> {@code
2705 >     * Map<Key, String> map = ...;
2706 >     * final String msg = ...;
2707 >     * map.compute(key, new BiFun<Key, String, String>() {
2708 >     *   public String apply(Key k, String v) {
2709 >     *    return (v == null) ? msg : v + msg;});}}</pre>
2710       *
2711       * @param key key with which the specified value is to be associated
2712 <     * @param mappingFunction the function to compute a value
2713 <     * @return the current value associated with
2714 <     *         the specified key, or {@code null} if the computation
1155 <     *         returned {@code null} and the value was not otherwise present
1156 <     * @throws NullPointerException if the specified key or mappingFunction
2712 >     * @param remappingFunction the function to compute a value
2713 >     * @return the new value associated with the specified key, or null if none
2714 >     * @throws NullPointerException if the specified key or remappingFunction
2715       *         is null
2716       * @throws IllegalStateException if the computation detectably
2717       *         attempts a recursive update to this map that would
2718       *         otherwise never complete
2719 <     * @throws RuntimeException or Error if the mappingFunction does so,
2719 >     * @throws RuntimeException or Error if the remappingFunction does so,
2720       *         in which case the mapping is unchanged
2721       */
2722 <    public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2723 <        if (key == null || mappingFunction == null)
2722 >    @SuppressWarnings("unchecked") public V compute
2723 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2724 >        if (key == null || remappingFunction == null)
2725 >            throw new NullPointerException();
2726 >        return (V)internalCompute(key, false, remappingFunction);
2727 >    }
2728 >
2729 >    /**
2730 >     * If the specified key is not already associated
2731 >     * with a value, associate it with the given value.
2732 >     * Otherwise, replace the value with the results of
2733 >     * the given remapping function. This is equivalent to:
2734 >     *  <pre> {@code
2735 >     *   if (!map.containsKey(key))
2736 >     *     map.put(value);
2737 >     *   else {
2738 >     *     newValue = remappingFunction.apply(map.get(key), value);
2739 >     *     if (value != null)
2740 >     *       map.put(key, value);
2741 >     *     else
2742 >     *       map.remove(key);
2743 >     *   }
2744 >     * }</pre>
2745 >     * except that the action is performed atomically.  If the
2746 >     * function returns {@code null}, the mapping is removed.  If the
2747 >     * function itself throws an (unchecked) exception, the exception
2748 >     * is rethrown to its caller, and the current mapping is left
2749 >     * unchanged.  Some attempted update operations on this map by
2750 >     * other threads may be blocked while computation is in progress,
2751 >     * so the computation should be short and simple, and must not
2752 >     * attempt to update any other mappings of this Map.
2753 >     */
2754 >    @SuppressWarnings("unchecked") public V merge
2755 >        (K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
2756 >        if (key == null || value == null || remappingFunction == null)
2757              throw new NullPointerException();
2758 <        return internalCompute(key, mappingFunction, true);
2758 >        return (V)internalMerge(key, value, remappingFunction);
2759      }
2760  
2761      /**
# Line 1176 | Line 2767 | public class ConcurrentHashMapV8<K, V>
2767       *         {@code null} if there was no mapping for {@code key}
2768       * @throws NullPointerException if the specified key is null
2769       */
2770 <    @SuppressWarnings("unchecked")
1180 <    public V remove(Object key) {
2770 >    @SuppressWarnings("unchecked") public V remove(Object key) {
2771          if (key == null)
2772              throw new NullPointerException();
2773          return (V)internalReplace(key, null, null);
# Line 1214 | Line 2804 | public class ConcurrentHashMapV8<K, V>
2804       *         or {@code null} if there was no mapping for the key
2805       * @throws NullPointerException if the specified key or value is null
2806       */
2807 <    @SuppressWarnings("unchecked")
1218 <    public V replace(K key, V value) {
2807 >    @SuppressWarnings("unchecked") public V replace(K key, V value) {
2808          if (key == null || value == null)
2809              throw new NullPointerException();
2810          return (V)internalReplace(key, value, null);
# Line 1312 | Line 2901 | public class ConcurrentHashMapV8<K, V>
2901      }
2902  
2903      /**
2904 +     * Returns a partitionable iterator of the keys in this map.
2905 +     *
2906 +     * @return a partitionable iterator of the keys in this map
2907 +     */
2908 +    public Spliterator<K> keySpliterator() {
2909 +        return new KeyIterator<K,V>(this);
2910 +    }
2911 +
2912 +    /**
2913 +     * Returns a partitionable iterator of the values in this map.
2914 +     *
2915 +     * @return a partitionable iterator of the values in this map
2916 +     */
2917 +    public Spliterator<V> valueSpliterator() {
2918 +        return new ValueIterator<K,V>(this);
2919 +    }
2920 +
2921 +    /**
2922 +     * Returns a partitionable iterator of the entries in this map.
2923 +     *
2924 +     * @return a partitionable iterator of the entries in this map
2925 +     */
2926 +    public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2927 +        return new EntryIterator<K,V>(this);
2928 +    }
2929 +
2930 +    /**
2931       * Returns the hash code value for this {@link Map}, i.e.,
2932       * the sum of, for each key-value pair in the map,
2933       * {@code key.hashCode() ^ value.hashCode()}.
# Line 1320 | Line 2936 | public class ConcurrentHashMapV8<K, V>
2936       */
2937      public int hashCode() {
2938          int h = 0;
2939 <        InternalIterator it = new InternalIterator(table);
2940 <        while (it.next != null) {
2941 <            h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
2942 <            it.advance();
2939 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2940 >        Object v;
2941 >        while ((v = it.advance()) != null) {
2942 >            h += it.nextKey.hashCode() ^ v.hashCode();
2943          }
2944          return h;
2945      }
# Line 1340 | Line 2956 | public class ConcurrentHashMapV8<K, V>
2956       * @return a string representation of this map
2957       */
2958      public String toString() {
2959 <        InternalIterator it = new InternalIterator(table);
2959 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2960          StringBuilder sb = new StringBuilder();
2961          sb.append('{');
2962 <        if (it.next != null) {
2962 >        Object v;
2963 >        if ((v = it.advance()) != null) {
2964              for (;;) {
2965 <                Object k = it.nextKey, v = it.nextVal;
2965 >                Object k = it.nextKey;
2966                  sb.append(k == this ? "(this Map)" : k);
2967                  sb.append('=');
2968                  sb.append(v == this ? "(this Map)" : v);
2969 <                it.advance();
1353 <                if (it.next == null)
2969 >                if ((v = it.advance()) == null)
2970                      break;
2971                  sb.append(',').append(' ');
2972              }
# Line 1373 | Line 2989 | public class ConcurrentHashMapV8<K, V>
2989              if (!(o instanceof Map))
2990                  return false;
2991              Map<?,?> m = (Map<?,?>) o;
2992 <            InternalIterator it = new InternalIterator(table);
2993 <            while (it.next != null) {
2994 <                Object val = it.nextVal;
2992 >            Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2993 >            Object val;
2994 >            while ((val = it.advance()) != null) {
2995                  Object v = m.get(it.nextKey);
2996                  if (v == null || (v != val && !v.equals(val)))
2997                      return false;
1382                it.advance();
2998              }
2999              for (Map.Entry<?,?> e : m.entrySet()) {
3000                  Object mk, mv, v;
# Line 1395 | Line 3010 | public class ConcurrentHashMapV8<K, V>
3010  
3011      /* ----------------Iterators -------------- */
3012  
3013 <    /**
3014 <     * Base class for key, value, and entry iterators.  Adds a map
3015 <     * reference to InternalIterator to support Iterator.remove.
3016 <     */
3017 <    static abstract class ViewIterator<K,V> extends InternalIterator {
1403 <        final ConcurrentHashMapV8<K, V> map;
1404 <        ViewIterator(ConcurrentHashMapV8<K, V> map) {
1405 <            super(map.table);
1406 <            this.map = map;
3013 >    @SuppressWarnings("serial") static final class KeyIterator<K,V> extends Traverser<K,V,Object>
3014 >        implements Spliterator<K>, Enumeration<K> {
3015 >        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3016 >        KeyIterator(Traverser<K,V,Object> it) {
3017 >            super(it);
3018          }
3019 <
3020 <        public final void remove() {
1410 <            if (last == null)
3019 >        public KeyIterator<K,V> split() {
3020 >            if (last != null || (next != null && nextVal == null))
3021                  throw new IllegalStateException();
3022 <            map.remove(last.key);
1413 <            last = null;
3022 >            return new KeyIterator<K,V>(this);
3023          }
3024 <
3025 <        public final boolean hasNext()         { return next != null; }
1417 <        public final boolean hasMoreElements() { return next != null; }
1418 <    }
1419 <
1420 <    static final class KeyIterator<K,V> extends ViewIterator<K,V>
1421 <        implements Iterator<K>, Enumeration<K> {
1422 <        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1423 <
1424 <        @SuppressWarnings("unchecked")
1425 <        public final K next() {
1426 <            if (next == null)
3024 >        @SuppressWarnings("unchecked") public final K next() {
3025 >            if (nextVal == null && advance() == null)
3026                  throw new NoSuchElementException();
3027              Object k = nextKey;
3028 <            advance();
3029 <            return (K)k;
3028 >            nextVal = null;
3029 >            return (K) k;
3030          }
3031  
3032          public final K nextElement() { return next(); }
3033      }
3034  
3035 <    static final class ValueIterator<K,V> extends ViewIterator<K,V>
3036 <        implements Iterator<V>, Enumeration<V> {
3035 >    @SuppressWarnings("serial") static final class ValueIterator<K,V> extends Traverser<K,V,Object>
3036 >        implements Spliterator<V>, Enumeration<V> {
3037          ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3038 +        ValueIterator(Traverser<K,V,Object> it) {
3039 +            super(it);
3040 +        }
3041 +        public ValueIterator<K,V> split() {
3042 +            if (last != null || (next != null && nextVal == null))
3043 +                throw new IllegalStateException();
3044 +            return new ValueIterator<K,V>(this);
3045 +        }
3046  
3047 <        @SuppressWarnings("unchecked")
3048 <        public final V next() {
3049 <            if (next == null)
3047 >        @SuppressWarnings("unchecked") public final V next() {
3048 >            Object v;
3049 >            if ((v = nextVal) == null && (v = advance()) == null)
3050                  throw new NoSuchElementException();
3051 <            Object v = nextVal;
3052 <            advance();
1446 <            return (V)v;
3051 >            nextVal = null;
3052 >            return (V) v;
3053          }
3054  
3055          public final V nextElement() { return next(); }
3056      }
3057  
3058 <    static final class EntryIterator<K,V> extends ViewIterator<K,V>
3059 <        implements Iterator<Map.Entry<K,V>> {
3058 >    @SuppressWarnings("serial") static final class EntryIterator<K,V> extends Traverser<K,V,Object>
3059 >        implements Spliterator<Map.Entry<K,V>> {
3060          EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3061 +        EntryIterator(Traverser<K,V,Object> it) {
3062 +            super(it);
3063 +        }
3064 +        public EntryIterator<K,V> split() {
3065 +            if (last != null || (next != null && nextVal == null))
3066 +                throw new IllegalStateException();
3067 +            return new EntryIterator<K,V>(this);
3068 +        }
3069  
3070 <        @SuppressWarnings("unchecked")
3071 <        public final Map.Entry<K,V> next() {
3072 <            if (next == null)
3070 >        @SuppressWarnings("unchecked") public final Map.Entry<K,V> next() {
3071 >            Object v;
3072 >            if ((v = nextVal) == null && (v = advance()) == null)
3073                  throw new NoSuchElementException();
3074              Object k = nextKey;
3075 <            Object v = nextVal;
3076 <            advance();
1463 <            return new WriteThroughEntry<K,V>(map, (K)k, (V)v);
3075 >            nextVal = null;
3076 >            return new MapEntry<K,V>((K)k, (V)v, map);
3077          }
3078      }
3079  
3080      /**
3081 <     * Custom Entry class used by EntryIterator.next(), that relays
1469 <     * setValue changes to the underlying map.
3081 >     * Exported Entry for iterators
3082       */
3083 <    static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> {
1472 <        final ConcurrentHashMapV8<K, V> map;
3083 >    static final class MapEntry<K,V> implements Map.Entry<K, V> {
3084          final K key; // non-null
3085          V val;       // non-null
3086 <        WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) {
3087 <            this.map = map; this.key = key; this.val = val;
3086 >        final ConcurrentHashMapV8<K, V> map;
3087 >        MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
3088 >            this.key = key;
3089 >            this.val = val;
3090 >            this.map = map;
3091          }
1478
3092          public final K getKey()       { return key; }
3093          public final V getValue()     { return val; }
3094          public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
# Line 1492 | Line 3105 | public class ConcurrentHashMapV8<K, V>
3105  
3106          /**
3107           * Sets our entry's value and writes through to the map. The
3108 <         * value to return is somewhat arbitrary here. Since a
3109 <         * WriteThroughEntry does not necessarily track asynchronous
3110 <         * changes, the most recent "previous" value could be
3111 <         * different from what we return (or could even have been
3112 <         * removed in which case the put will re-establish). We do not
1500 <         * and cannot guarantee more.
3108 >         * value to return is somewhat arbitrary here. Since we do not
3109 >         * necessarily track asynchronous changes, the most recent
3110 >         * "previous" value could be different from what we return (or
3111 >         * could even have been removed in which case the put will
3112 >         * re-establish). We do not and cannot guarantee more.
3113           */
3114          public final V setValue(V value) {
3115              if (value == null) throw new NullPointerException();
# Line 1510 | Line 3122 | public class ConcurrentHashMapV8<K, V>
3122  
3123      /* ----------------Views -------------- */
3124  
3125 <    /*
3126 <     * These currently just extend java.util.AbstractX classes, but
1515 <     * may need a new custom base to support partitioned traversal.
3125 >    /**
3126 >     * Base class for views.
3127       */
3128 <
1518 <    static final class KeySet<K,V> extends AbstractSet<K> {
3128 >    static abstract class CHMView<K, V> {
3129          final ConcurrentHashMapV8<K, V> map;
3130 <        KeySet(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1521 <
3130 >        CHMView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
3131          public final int size()                 { return map.size(); }
3132          public final boolean isEmpty()          { return map.isEmpty(); }
3133          public final void clear()               { map.clear(); }
3134 +
3135 +        // implementations below rely on concrete classes supplying these
3136 +        abstract public Iterator<?> iterator();
3137 +        abstract public boolean contains(Object o);
3138 +        abstract public boolean remove(Object o);
3139 +
3140 +        private static final String oomeMsg = "Required array size too large";
3141 +
3142 +        public final Object[] toArray() {
3143 +            long sz = map.mappingCount();
3144 +            if (sz > (long)(MAX_ARRAY_SIZE))
3145 +                throw new OutOfMemoryError(oomeMsg);
3146 +            int n = (int)sz;
3147 +            Object[] r = new Object[n];
3148 +            int i = 0;
3149 +            Iterator<?> it = iterator();
3150 +            while (it.hasNext()) {
3151 +                if (i == n) {
3152 +                    if (n >= MAX_ARRAY_SIZE)
3153 +                        throw new OutOfMemoryError(oomeMsg);
3154 +                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3155 +                        n = MAX_ARRAY_SIZE;
3156 +                    else
3157 +                        n += (n >>> 1) + 1;
3158 +                    r = Arrays.copyOf(r, n);
3159 +                }
3160 +                r[i++] = it.next();
3161 +            }
3162 +            return (i == n) ? r : Arrays.copyOf(r, i);
3163 +        }
3164 +
3165 +        @SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
3166 +            long sz = map.mappingCount();
3167 +            if (sz > (long)(MAX_ARRAY_SIZE))
3168 +                throw new OutOfMemoryError(oomeMsg);
3169 +            int m = (int)sz;
3170 +            T[] r = (a.length >= m) ? a :
3171 +                (T[])java.lang.reflect.Array
3172 +                .newInstance(a.getClass().getComponentType(), m);
3173 +            int n = r.length;
3174 +            int i = 0;
3175 +            Iterator<?> it = iterator();
3176 +            while (it.hasNext()) {
3177 +                if (i == n) {
3178 +                    if (n >= MAX_ARRAY_SIZE)
3179 +                        throw new OutOfMemoryError(oomeMsg);
3180 +                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3181 +                        n = MAX_ARRAY_SIZE;
3182 +                    else
3183 +                        n += (n >>> 1) + 1;
3184 +                    r = Arrays.copyOf(r, n);
3185 +                }
3186 +                r[i++] = (T)it.next();
3187 +            }
3188 +            if (a == r && i < n) {
3189 +                r[i] = null; // null-terminate
3190 +                return r;
3191 +            }
3192 +            return (i == n) ? r : Arrays.copyOf(r, i);
3193 +        }
3194 +
3195 +        public final int hashCode() {
3196 +            int h = 0;
3197 +            for (Iterator<?> it = iterator(); it.hasNext();)
3198 +                h += it.next().hashCode();
3199 +            return h;
3200 +        }
3201 +
3202 +        public final String toString() {
3203 +            StringBuilder sb = new StringBuilder();
3204 +            sb.append('[');
3205 +            Iterator<?> it = iterator();
3206 +            if (it.hasNext()) {
3207 +                for (;;) {
3208 +                    Object e = it.next();
3209 +                    sb.append(e == this ? "(this Collection)" : e);
3210 +                    if (!it.hasNext())
3211 +                        break;
3212 +                    sb.append(',').append(' ');
3213 +                }
3214 +            }
3215 +            return sb.append(']').toString();
3216 +        }
3217 +
3218 +        public final boolean containsAll(Collection<?> c) {
3219 +            if (c != this) {
3220 +                for (Iterator<?> it = c.iterator(); it.hasNext();) {
3221 +                    Object e = it.next();
3222 +                    if (e == null || !contains(e))
3223 +                        return false;
3224 +                }
3225 +            }
3226 +            return true;
3227 +        }
3228 +
3229 +        public final boolean removeAll(Collection<?> c) {
3230 +            boolean modified = false;
3231 +            for (Iterator<?> it = iterator(); it.hasNext();) {
3232 +                if (c.contains(it.next())) {
3233 +                    it.remove();
3234 +                    modified = true;
3235 +                }
3236 +            }
3237 +            return modified;
3238 +        }
3239 +
3240 +        public final boolean retainAll(Collection<?> c) {
3241 +            boolean modified = false;
3242 +            for (Iterator<?> it = iterator(); it.hasNext();) {
3243 +                if (!c.contains(it.next())) {
3244 +                    it.remove();
3245 +                    modified = true;
3246 +                }
3247 +            }
3248 +            return modified;
3249 +        }
3250 +
3251 +    }
3252 +
3253 +    static final class KeySet<K,V> extends CHMView<K,V> implements Set<K> {
3254 +        KeySet(ConcurrentHashMapV8<K, V> map)  {
3255 +            super(map);
3256 +        }
3257          public final boolean contains(Object o) { return map.containsKey(o); }
3258          public final boolean remove(Object o)   { return map.remove(o) != null; }
3259          public final Iterator<K> iterator() {
3260              return new KeyIterator<K,V>(map);
3261          }
3262 +        public final boolean add(K e) {
3263 +            throw new UnsupportedOperationException();
3264 +        }
3265 +        public final boolean addAll(Collection<? extends K> c) {
3266 +            throw new UnsupportedOperationException();
3267 +        }
3268 +        public boolean equals(Object o) {
3269 +            Set<?> c;
3270 +            return ((o instanceof Set) &&
3271 +                    ((c = (Set<?>)o) == this ||
3272 +                     (containsAll(c) && c.containsAll(this))));
3273 +        }
3274      }
3275  
1532    static final class Values<K,V> extends AbstractCollection<V> {
1533        final ConcurrentHashMapV8<K, V> map;
1534        Values(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
3276  
3277 <        public final int size()                 { return map.size(); }
3278 <        public final boolean isEmpty()          { return map.isEmpty(); }
3279 <        public final void clear()               { map.clear(); }
3277 >    static final class Values<K,V> extends CHMView<K,V>
3278 >        implements Collection<V> {
3279 >        Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3280          public final boolean contains(Object o) { return map.containsValue(o); }
3281 +        public final boolean remove(Object o) {
3282 +            if (o != null) {
3283 +                Iterator<V> it = new ValueIterator<K,V>(map);
3284 +                while (it.hasNext()) {
3285 +                    if (o.equals(it.next())) {
3286 +                        it.remove();
3287 +                        return true;
3288 +                    }
3289 +                }
3290 +            }
3291 +            return false;
3292 +        }
3293          public final Iterator<V> iterator() {
3294              return new ValueIterator<K,V>(map);
3295          }
3296 <    }
3297 <
3298 <    static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> {
3299 <        final ConcurrentHashMapV8<K, V> map;
3300 <        EntrySet(ConcurrentHashMapV8<K, V> map) { this.map = map; }
1548 <
1549 <        public final int size()                 { return map.size(); }
1550 <        public final boolean isEmpty()          { return map.isEmpty(); }
1551 <        public final void clear()               { map.clear(); }
1552 <        public final Iterator<Map.Entry<K,V>> iterator() {
1553 <            return new EntryIterator<K,V>(map);
3296 >        public final boolean add(V e) {
3297 >            throw new UnsupportedOperationException();
3298 >        }
3299 >        public final boolean addAll(Collection<? extends V> c) {
3300 >            throw new UnsupportedOperationException();
3301          }
3302  
3303 +    }
3304 +
3305 +    static final class EntrySet<K,V> extends CHMView<K,V>
3306 +        implements Set<Map.Entry<K,V>> {
3307 +        EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3308          public final boolean contains(Object o) {
3309              Object k, v, r; Map.Entry<?,?> e;
3310              return ((o instanceof Map.Entry) &&
# Line 1561 | Line 3313 | public class ConcurrentHashMapV8<K, V>
3313                      (v = e.getValue()) != null &&
3314                      (v == r || v.equals(r)));
3315          }
1564
3316          public final boolean remove(Object o) {
3317              Object k, v; Map.Entry<?,?> e;
3318              return ((o instanceof Map.Entry) &&
# Line 1569 | Line 3320 | public class ConcurrentHashMapV8<K, V>
3320                      (v = e.getValue()) != null &&
3321                      map.remove(k, v));
3322          }
3323 +        public final Iterator<Map.Entry<K,V>> iterator() {
3324 +            return new EntryIterator<K,V>(map);
3325 +        }
3326 +        public final boolean add(Entry<K,V> e) {
3327 +            throw new UnsupportedOperationException();
3328 +        }
3329 +        public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3330 +            throw new UnsupportedOperationException();
3331 +        }
3332 +        public boolean equals(Object o) {
3333 +            Set<?> c;
3334 +            return ((o instanceof Set) &&
3335 +                    ((c = (Set<?>)o) == this ||
3336 +                     (containsAll(c) && c.containsAll(this))));
3337 +        }
3338      }
3339  
3340      /* ---------------- Serialization Support -------------- */
# Line 1592 | Line 3358 | public class ConcurrentHashMapV8<K, V>
3358       * for each key-value mapping, followed by a null pair.
3359       * The key-value mappings are emitted in no particular order.
3360       */
3361 <    @SuppressWarnings("unchecked")
3362 <    private void writeObject(java.io.ObjectOutputStream s)
1597 <            throws java.io.IOException {
3361 >    @SuppressWarnings("unchecked") private void writeObject(java.io.ObjectOutputStream s)
3362 >        throws java.io.IOException {
3363          if (segments == null) { // for serialization compatibility
3364              segments = (Segment<K,V>[])
3365                  new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
# Line 1602 | Line 3367 | public class ConcurrentHashMapV8<K, V>
3367                  segments[i] = new Segment<K,V>(LOAD_FACTOR);
3368          }
3369          s.defaultWriteObject();
3370 <        InternalIterator it = new InternalIterator(table);
3371 <        while (it.next != null) {
3370 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3371 >        Object v;
3372 >        while ((v = it.advance()) != null) {
3373              s.writeObject(it.nextKey);
3374 <            s.writeObject(it.nextVal);
1609 <            it.advance();
3374 >            s.writeObject(v);
3375          }
3376          s.writeObject(null);
3377          s.writeObject(null);
# Line 1617 | Line 3382 | public class ConcurrentHashMapV8<K, V>
3382       * Reconstitutes the instance from a stream (that is, deserializes it).
3383       * @param s the stream
3384       */
3385 <    @SuppressWarnings("unchecked")
3386 <    private void readObject(java.io.ObjectInputStream s)
1622 <            throws java.io.IOException, ClassNotFoundException {
3385 >    @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s)
3386 >        throws java.io.IOException, ClassNotFoundException {
3387          s.defaultReadObject();
3388          this.segments = null; // unneeded
3389          // initialize transient final field
3390          UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
1627        this.targetCapacity = DEFAULT_CAPACITY;
3391  
3392          // Create all nodes, then place in table once size is known
3393          long size = 0L;
# Line 1633 | Line 3396 | public class ConcurrentHashMapV8<K, V>
3396              K k = (K) s.readObject();
3397              V v = (V) s.readObject();
3398              if (k != null && v != null) {
3399 <                p = new Node(spread(k.hashCode()), k, v, p);
3399 >                int h = spread(k.hashCode());
3400 >                p = new Node(h, k, v, p);
3401                  ++size;
3402              }
3403              else
# Line 1641 | Line 3405 | public class ConcurrentHashMapV8<K, V>
3405          }
3406          if (p != null) {
3407              boolean init = false;
3408 <            if (resizing == 0 &&
3409 <                UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
3408 >            int n;
3409 >            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3410 >                n = MAXIMUM_CAPACITY;
3411 >            else {
3412 >                int sz = (int)size;
3413 >                n = tableSizeFor(sz + (sz >>> 1) + 1);
3414 >            }
3415 >            int sc = sizeCtl;
3416 >            boolean collide = false;
3417 >            if (n > sc &&
3418 >                UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3419                  try {
3420                      if (table == null) {
3421                          init = true;
1649                        int n;
1650                        if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1651                            n = MAXIMUM_CAPACITY;
1652                        else {
1653                            int sz = (int)size;
1654                            n = tableSizeFor(sz + (sz >>> 1) + 1);
1655                        }
1656                        threshold = n - (n >>> 2) - THRESHOLD_OFFSET;
3422                          Node[] tab = new Node[n];
3423                          int mask = n - 1;
3424                          while (p != null) {
3425                              int j = p.hash & mask;
3426                              Node next = p.next;
3427 <                            p.next = tabAt(tab, j);
3427 >                            Node q = p.next = tabAt(tab, j);
3428                              setTabAt(tab, j, p);
3429 +                            if (!collide && q != null && q.hash == p.hash)
3430 +                                collide = true;
3431                              p = next;
3432                          }
3433                          table = tab;
3434                          counter.add(size);
3435 +                        sc = n - (n >>> 2);
3436                      }
3437                  } finally {
3438 <                    resizing = 0;
3438 >                    sizeCtl = sc;
3439 >                }
3440 >                if (collide) { // rescan and convert to TreeBins
3441 >                    Node[] tab = table;
3442 >                    for (int i = 0; i < tab.length; ++i) {
3443 >                        int c = 0;
3444 >                        for (Node e = tabAt(tab, i); e != null; e = e.next) {
3445 >                            if (++c > TREE_THRESHOLD &&
3446 >                                (e.key instanceof Comparable)) {
3447 >                                replaceWithTreeBin(tab, i, e.key);
3448 >                                break;
3449 >                            }
3450 >                        }
3451 >                    }
3452                  }
3453              }
3454              if (!init) { // Can only happen if unsafely published.
3455                  while (p != null) {
3456 <                    internalPut(p.key, p.val, true);
3456 >                    internalPut(p.key, p.val);
3457                      p = p.next;
3458                  }
3459              }
3460          }
3461      }
3462  
3463 +
3464 +    // -------------------------------------------------------
3465 +
3466 +    // Sams
3467 +    /** Interface describing a void action of one argument */
3468 +    public interface Action<A> { void apply(A a); }
3469 +    /** Interface describing a void action of two arguments */
3470 +    public interface BiAction<A,B> { void apply(A a, B b); }
3471 +    /** Interface describing a function of one argument */
3472 +    public interface Fun<A,T> { T apply(A a); }
3473 +    /** Interface describing a function of two arguments */
3474 +    public interface BiFun<A,B,T> { T apply(A a, B b); }
3475 +    /** Interface describing a function of no arguments */
3476 +    public interface Generator<T> { T apply(); }
3477 +    /** Interface describing a function mapping its argument to a double */
3478 +    public interface ObjectToDouble<A> { double apply(A a); }
3479 +    /** Interface describing a function mapping its argument to a long */
3480 +    public interface ObjectToLong<A> { long apply(A a); }
3481 +    /** Interface describing a function mapping its argument to an int */
3482 +    public interface ObjectToInt<A> {int apply(A a); }
3483 +    /** Interface describing a function mapping two arguments to a double */
3484 +    public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
3485 +    /** Interface describing a function mapping two arguments to a long */
3486 +    public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
3487 +    /** Interface describing a function mapping two arguments to an int */
3488 +    public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }
3489 +    /** Interface describing a function mapping a double to a double */
3490 +    public interface DoubleToDouble { double apply(double a); }
3491 +    /** Interface describing a function mapping a long to a long */
3492 +    public interface LongToLong { long apply(long a); }
3493 +    /** Interface describing a function mapping an int to an int */
3494 +    public interface IntToInt { int apply(int a); }
3495 +    /** Interface describing a function mapping two doubles to a double */
3496 +    public interface DoubleByDoubleToDouble { double apply(double a, double b); }
3497 +    /** Interface describing a function mapping two longs to a long */
3498 +    public interface LongByLongToLong { long apply(long a, long b); }
3499 +    /** Interface describing a function mapping two ints to an int */
3500 +    public interface IntByIntToInt { int apply(int a, int b); }
3501 +
3502 +
3503 +    // -------------------------------------------------------
3504 +
3505 +    /**
3506 +     * Returns an extended {@link Parallel} view of this map using the
3507 +     * given executor for bulk parallel operations.
3508 +     *
3509 +     * @param executor the executor
3510 +     * @return a parallel view
3511 +     */
3512 +    public Parallel parallel(ForkJoinPool executor)  {
3513 +        return new Parallel(executor);
3514 +    }
3515 +
3516 +    /**
3517 +     * An extended view of a ConcurrentHashMap supporting bulk
3518 +     * parallel operations. These operations are designed to be
3519 +     * safely, and often sensibly, applied even with maps that are
3520 +     * being concurrently updated by other threads; for example, when
3521 +     * computing a snapshot summary of the values in a shared
3522 +     * registry.  There are three kinds of operation, each with four
3523 +     * forms, accepting functions with Keys, Values, Entries, and
3524 +     * (Key, Value) arguments and/or return values. Because the
3525 +     * elements of a ConcurrentHashMap are not ordered in any
3526 +     * particular way, and may be processed in different orders in
3527 +     * different parallel executions, the correctness of supplied
3528 +     * functions should not depend on any ordering, or on any other
3529 +     * objects or values that may transiently change while computation
3530 +     * is in progress; and except for forEach actions, should ideally
3531 +     * be side-effect-free.
3532 +     *
3533 +     * <ul>
3534 +     * <li> forEach: Perform a given action on each element.
3535 +     * A variant form applies a given transformation on each element
3536 +     * before performing the action.</li>
3537 +     *
3538 +     * <li> search: Return the first available non-null result of
3539 +     * applying a given function on each element; skipping further
3540 +     * search when a result is found.</li>
3541 +     *
3542 +     * <li> reduce: Accumulate each element.  The supplied reduction
3543 +     * function cannot rely on ordering (more formally, it should be
3544 +     * both associative and commutative).  There are five variants:
3545 +     *
3546 +     * <ul>
3547 +     *
3548 +     * <li> Plain reductions. (There is not a form of this method for
3549 +     * (key, value) function arguments since there is no corresponding
3550 +     * return type.)</li>
3551 +     *
3552 +     * <li> Mapped reductions that accumulate the results of a given
3553 +     * function applied to each element.</li>
3554 +     *
3555 +     * <li> Reductions to scalar doubles, longs, and ints, using a
3556 +     * given basis value.</li>
3557 +     *
3558 +     * </li>
3559 +     * </ul>
3560 +     * </ul>
3561 +     *
3562 +     * <p>The concurrency properties of the bulk operations follow
3563 +     * from those of ConcurrentHashMap: Any non-null result returned
3564 +     * from {@code get(key)} and related access methods bears a
3565 +     * happens-before relation with the associated insertion or
3566 +     * update.  The result of any bulk operation reflects the
3567 +     * composition of these per-element relations (but is not
3568 +     * necessarily atomic with respect to the map as a whole unless it
3569 +     * is somehow known to be quiescent).  Conversely, because keys
3570 +     * and values in the map are never null, null serves as a reliable
3571 +     * atomic indicator of the current lack of any result.  To
3572 +     * maintain this property, null serves as an implicit basis for
3573 +     * all non-scalar reduction operations. For the double, long, and
3574 +     * int versions, the basis should be one that, when combined with
3575 +     * any other value, returns that other value (more formally, it
3576 +     * should be the identity element for the reduction). Most common
3577 +     * reductions have these properties; for example, computing a sum
3578 +     * with basis 0 or a minimum with basis MAX_VALUE.
3579 +     *
3580 +     * <p>Search and transformation functions provided as arguments
3581 +     * should similarly return null to indicate the lack of any result
3582 +     * (in which case it is not used). In the case of mapped
3583 +     * reductions, this also enables transformations to serve as
3584 +     * filters, returning null (or, in the case of primitive
3585 +     * specializations, the identity basis) if the element should not
3586 +     * be combined. You can create compound transformations and
3587 +     * filterings by composing them yourself under this "null means
3588 +     * there is nothing there now" rule before using them in search or
3589 +     * reduce operations.
3590 +     *
3591 +     * <p>Methods accepting and/or returning Entry arguments maintain
3592 +     * key-value associations. They may be useful for example when
3593 +     * finding the key for the greatest value. Note that "plain" Entry
3594 +     * arguments can be supplied using {@code new
3595 +     * AbstractMap.SimpleEntry(k,v)}.
3596 +     *
3597 +     * <p> Bulk operations may complete abruptly, throwing an
3598 +     * exception encountered in the application of a supplied
3599 +     * function. Bear in mind when handling such exceptions that other
3600 +     * concurrently executing functions could also have thrown
3601 +     * exceptions, or would have done so if the first exception had
3602 +     * not occurred.
3603 +     *
3604 +     * <p>Parallel speedups compared to sequential processing are
3605 +     * common but not guaranteed.  Operations involving brief
3606 +     * functions on small maps may execute more slowly than sequential
3607 +     * loops if the underlying work to parallelize the computation is
3608 +     * more expensive than the computation itself. Similarly,
3609 +     * parallelization may not lead to much actual parallelism if all
3610 +     * processors are busy performing unrelated tasks.
3611 +     *
3612 +     * <p> All arguments to all task methods must be non-null.
3613 +     *
3614 +     * <p><em>jsr166e note: During transition, this class
3615 +     * uses nested functional interfaces with different names but the
3616 +     * same forms as those expected for JDK8.<em>
3617 +     */
3618 +    public class Parallel {
3619 +        final ForkJoinPool fjp;
3620 +
3621 +        /**
3622 +         * Returns an extended view of this map using the given
3623 +         * executor for bulk parallel operations.
3624 +         *
3625 +         * @param executor the executor
3626 +         */
3627 +        public Parallel(ForkJoinPool executor)  {
3628 +            this.fjp = executor;
3629 +        }
3630 +
3631 +        /**
3632 +         * Performs the given action for each (key, value).
3633 +         *
3634 +         * @param action the action
3635 +         */
3636 +        public void forEach(BiAction<K,V> action) {
3637 +            fjp.invoke(ForkJoinTasks.forEach
3638 +                       (ConcurrentHashMapV8.this, action));
3639 +        }
3640 +
3641 +        /**
3642 +         * Performs the given action for each non-null transformation
3643 +         * of each (key, value).
3644 +         *
3645 +         * @param transformer a function returning the transformation
3646 +         * for an element, or null of there is no transformation (in
3647 +         * which case the action is not applied).
3648 +         * @param action the action
3649 +         */
3650 +        public <U> void forEach(BiFun<? super K, ? super V, ? extends U> transformer,
3651 +                                Action<U> action) {
3652 +            fjp.invoke(ForkJoinTasks.forEach
3653 +                       (ConcurrentHashMapV8.this, transformer, action));
3654 +        }
3655 +
3656 +        /**
3657 +         * Returns a non-null result from applying the given search
3658 +         * function on each (key, value), or null if none.  Upon
3659 +         * success, further element processing is suppressed and the
3660 +         * results of any other parallel invocations of the search
3661 +         * function are ignored.
3662 +         *
3663 +         * @param searchFunction a function returning a non-null
3664 +         * result on success, else null
3665 +         * @return a non-null result from applying the given search
3666 +         * function on each (key, value), or null if none
3667 +         */
3668 +        public <U> U search(BiFun<? super K, ? super V, ? extends U> searchFunction) {
3669 +            return fjp.invoke(ForkJoinTasks.search
3670 +                              (ConcurrentHashMapV8.this, searchFunction));
3671 +        }
3672 +
3673 +        /**
3674 +         * Returns the result of accumulating the given transformation
3675 +         * of all (key, value) pairs using the given reducer to
3676 +         * combine values, or null if none.
3677 +         *
3678 +         * @param transformer a function returning the transformation
3679 +         * for an element, or null of there is no transformation (in
3680 +         * which case it is not combined).
3681 +         * @param reducer a commutative associative combining function
3682 +         * @return the result of accumulating the given transformation
3683 +         * of all (key, value) pairs
3684 +         */
3685 +        public <U> U reduce(BiFun<? super K, ? super V, ? extends U> transformer,
3686 +                            BiFun<? super U, ? super U, ? extends U> reducer) {
3687 +            return fjp.invoke(ForkJoinTasks.reduce
3688 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3689 +        }
3690 +
3691 +        /**
3692 +         * Returns the result of accumulating the given transformation
3693 +         * of all (key, value) pairs using the given reducer to
3694 +         * combine values, and the given basis as an identity value.
3695 +         *
3696 +         * @param transformer a function returning the transformation
3697 +         * for an element
3698 +         * @param basis the identity (initial default value) for the reduction
3699 +         * @param reducer a commutative associative combining function
3700 +         * @return the result of accumulating the given transformation
3701 +         * of all (key, value) pairs
3702 +         */
3703 +        public double reduceToDouble(ObjectByObjectToDouble<? super K, ? super V> transformer,
3704 +                                     double basis,
3705 +                                     DoubleByDoubleToDouble reducer) {
3706 +            return fjp.invoke(ForkJoinTasks.reduceToDouble
3707 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3708 +        }
3709 +
3710 +        /**
3711 +         * Returns the result of accumulating the given transformation
3712 +         * of all (key, value) pairs using the given reducer to
3713 +         * combine values, and the given basis as an identity value.
3714 +         *
3715 +         * @param transformer a function returning the transformation
3716 +         * for an element
3717 +         * @param basis the identity (initial default value) for the reduction
3718 +         * @param reducer a commutative associative combining function
3719 +         * @return the result of accumulating the given transformation
3720 +         * of all (key, value) pairs
3721 +         */
3722 +        public long reduceToLong(ObjectByObjectToLong<? super K, ? super V> transformer,
3723 +                                 long basis,
3724 +                                 LongByLongToLong reducer) {
3725 +            return fjp.invoke(ForkJoinTasks.reduceToLong
3726 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3727 +        }
3728 +
3729 +        /**
3730 +         * Returns the result of accumulating the given transformation
3731 +         * of all (key, value) pairs using the given reducer to
3732 +         * combine values, and the given basis as an identity value.
3733 +         *
3734 +         * @param transformer a function returning the transformation
3735 +         * for an element
3736 +         * @param basis the identity (initial default value) for the reduction
3737 +         * @param reducer a commutative associative combining function
3738 +         * @return the result of accumulating the given transformation
3739 +         * of all (key, value) pairs
3740 +         */
3741 +        public int reduceToInt(ObjectByObjectToInt<? super K, ? super V> transformer,
3742 +                               int basis,
3743 +                               IntByIntToInt reducer) {
3744 +            return fjp.invoke(ForkJoinTasks.reduceToInt
3745 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3746 +        }
3747 +
3748 +        /**
3749 +         * Performs the given action for each key.
3750 +         *
3751 +         * @param action the action
3752 +         */
3753 +        public void forEachKey(Action<K> action) {
3754 +            fjp.invoke(ForkJoinTasks.forEachKey
3755 +                       (ConcurrentHashMapV8.this, action));
3756 +        }
3757 +
3758 +        /**
3759 +         * Performs the given action for each non-null transformation
3760 +         * of each key.
3761 +         *
3762 +         * @param transformer a function returning the transformation
3763 +         * for an element, or null of there is no transformation (in
3764 +         * which case the action is not applied).
3765 +         * @param action the action
3766 +         */
3767 +        public <U> void forEachKey(Fun<? super K, ? extends U> transformer,
3768 +                                   Action<U> action) {
3769 +            fjp.invoke(ForkJoinTasks.forEachKey
3770 +                       (ConcurrentHashMapV8.this, transformer, action));
3771 +        }
3772 +
3773 +        /**
3774 +         * Returns a non-null result from applying the given search
3775 +         * function on each key, or null if none. Upon success,
3776 +         * further element processing is suppressed and the results of
3777 +         * any other parallel invocations of the search function are
3778 +         * ignored.
3779 +         *
3780 +         * @param searchFunction a function returning a non-null
3781 +         * result on success, else null
3782 +         * @return a non-null result from applying the given search
3783 +         * function on each key, or null if none
3784 +         */
3785 +        public <U> U searchKeys(Fun<? super K, ? extends U> searchFunction) {
3786 +            return fjp.invoke(ForkJoinTasks.searchKeys
3787 +                              (ConcurrentHashMapV8.this, searchFunction));
3788 +        }
3789 +
3790 +        /**
3791 +         * Returns the result of accumulating all keys using the given
3792 +         * reducer to combine values, or null if none.
3793 +         *
3794 +         * @param reducer a commutative associative combining function
3795 +         * @return the result of accumulating all keys using the given
3796 +         * reducer to combine values, or null if none
3797 +         */
3798 +        public K reduceKeys(BiFun<? super K, ? super K, ? extends K> reducer) {
3799 +            return fjp.invoke(ForkJoinTasks.reduceKeys
3800 +                              (ConcurrentHashMapV8.this, reducer));
3801 +        }
3802 +
3803 +        /**
3804 +         * Returns the result of accumulating the given transformation
3805 +         * of all keys using the given reducer to combine values, or
3806 +         * null if none.
3807 +         *
3808 +         * @param transformer a function returning the transformation
3809 +         * for an element, or null of there is no transformation (in
3810 +         * which case it is not combined).
3811 +         * @param reducer a commutative associative combining function
3812 +         * @return the result of accumulating the given transformation
3813 +         * of all keys
3814 +         */
3815 +        public <U> U reduceKeys(Fun<? super K, ? extends U> transformer,
3816 +                                BiFun<? super U, ? super U, ? extends U> reducer) {
3817 +            return fjp.invoke(ForkJoinTasks.reduceKeys
3818 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3819 +        }
3820 +
3821 +        /**
3822 +         * Returns the result of accumulating the given transformation
3823 +         * of all keys using the given reducer to combine values, and
3824 +         * the given basis as an identity value.
3825 +         *
3826 +         * @param transformer a function returning the transformation
3827 +         * for an element
3828 +         * @param basis the identity (initial default value) for the reduction
3829 +         * @param reducer a commutative associative combining function
3830 +         * @return  the result of accumulating the given transformation
3831 +         * of all keys
3832 +         */
3833 +        public double reduceKeysToDouble(ObjectToDouble<? super K> transformer,
3834 +                                         double basis,
3835 +                                         DoubleByDoubleToDouble reducer) {
3836 +            return fjp.invoke(ForkJoinTasks.reduceKeysToDouble
3837 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3838 +        }
3839 +
3840 +        /**
3841 +         * Returns the result of accumulating the given transformation
3842 +         * of all keys using the given reducer to combine values, and
3843 +         * the given basis as an identity value.
3844 +         *
3845 +         * @param transformer a function returning the transformation
3846 +         * for an element
3847 +         * @param basis the identity (initial default value) for the reduction
3848 +         * @param reducer a commutative associative combining function
3849 +         * @return the result of accumulating the given transformation
3850 +         * of all keys
3851 +         */
3852 +        public long reduceKeysToLong(ObjectToLong<? super K> transformer,
3853 +                                     long basis,
3854 +                                     LongByLongToLong reducer) {
3855 +            return fjp.invoke(ForkJoinTasks.reduceKeysToLong
3856 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3857 +        }
3858 +
3859 +        /**
3860 +         * Returns the result of accumulating the given transformation
3861 +         * of all keys using the given reducer to combine values, and
3862 +         * the given basis as an identity value.
3863 +         *
3864 +         * @param transformer a function returning the transformation
3865 +         * for an element
3866 +         * @param basis the identity (initial default value) for the reduction
3867 +         * @param reducer a commutative associative combining function
3868 +         * @return the result of accumulating the given transformation
3869 +         * of all keys
3870 +         */
3871 +        public int reduceKeysToInt(ObjectToInt<? super K> transformer,
3872 +                                   int basis,
3873 +                                   IntByIntToInt reducer) {
3874 +            return fjp.invoke(ForkJoinTasks.reduceKeysToInt
3875 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3876 +        }
3877 +
3878 +        /**
3879 +         * Performs the given action for each value.
3880 +         *
3881 +         * @param action the action
3882 +         */
3883 +        public void forEachValue(Action<V> action) {
3884 +            fjp.invoke(ForkJoinTasks.forEachValue
3885 +                       (ConcurrentHashMapV8.this, action));
3886 +        }
3887 +
3888 +        /**
3889 +         * Performs the given action for each non-null transformation
3890 +         * of each value.
3891 +         *
3892 +         * @param transformer a function returning the transformation
3893 +         * for an element, or null of there is no transformation (in
3894 +         * which case the action is not applied).
3895 +         */
3896 +        public <U> void forEachValue(Fun<? super V, ? extends U> transformer,
3897 +                                     Action<U> action) {
3898 +            fjp.invoke(ForkJoinTasks.forEachValue
3899 +                       (ConcurrentHashMapV8.this, transformer, action));
3900 +        }
3901 +
3902 +        /**
3903 +         * Returns a non-null result from applying the given search
3904 +         * function on each value, or null if none.  Upon success,
3905 +         * further element processing is suppressed and the results of
3906 +         * any other parallel invocations of the search function are
3907 +         * ignored.
3908 +         *
3909 +         * @param searchFunction a function returning a non-null
3910 +         * result on success, else null
3911 +         * @return a non-null result from applying the given search
3912 +         * function on each value, or null if none
3913 +         *
3914 +         */
3915 +        public <U> U searchValues(Fun<? super V, ? extends U> searchFunction) {
3916 +            return fjp.invoke(ForkJoinTasks.searchValues
3917 +                              (ConcurrentHashMapV8.this, searchFunction));
3918 +        }
3919 +
3920 +        /**
3921 +         * Returns the result of accumulating all values using the
3922 +         * given reducer to combine values, or null if none.
3923 +         *
3924 +         * @param reducer a commutative associative combining function
3925 +         * @return  the result of accumulating all values
3926 +         */
3927 +        public V reduceValues(BiFun<? super V, ? super V, ? extends V> reducer) {
3928 +            return fjp.invoke(ForkJoinTasks.reduceValues
3929 +                              (ConcurrentHashMapV8.this, reducer));
3930 +        }
3931 +
3932 +        /**
3933 +         * Returns the result of accumulating the given transformation
3934 +         * of all values using the given reducer to combine values, or
3935 +         * null if none.
3936 +         *
3937 +         * @param transformer a function returning the transformation
3938 +         * for an element, or null of there is no transformation (in
3939 +         * which case it is not combined).
3940 +         * @param reducer a commutative associative combining function
3941 +         * @return the result of accumulating the given transformation
3942 +         * of all values
3943 +         */
3944 +        public <U> U reduceValues(Fun<? super V, ? extends U> transformer,
3945 +                                  BiFun<? super U, ? super U, ? extends U> reducer) {
3946 +            return fjp.invoke(ForkJoinTasks.reduceValues
3947 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3948 +        }
3949 +
3950 +        /**
3951 +         * Returns the result of accumulating the given transformation
3952 +         * of all values using the given reducer to combine values,
3953 +         * and the given basis as an identity value.
3954 +         *
3955 +         * @param transformer a function returning the transformation
3956 +         * for an element
3957 +         * @param basis the identity (initial default value) for the reduction
3958 +         * @param reducer a commutative associative combining function
3959 +         * @return the result of accumulating the given transformation
3960 +         * of all values
3961 +         */
3962 +        public double reduceValuesToDouble(ObjectToDouble<? super V> transformer,
3963 +                                           double basis,
3964 +                                           DoubleByDoubleToDouble reducer) {
3965 +            return fjp.invoke(ForkJoinTasks.reduceValuesToDouble
3966 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3967 +        }
3968 +
3969 +        /**
3970 +         * Returns the result of accumulating the given transformation
3971 +         * of all values using the given reducer to combine values,
3972 +         * and the given basis as an identity value.
3973 +         *
3974 +         * @param transformer a function returning the transformation
3975 +         * for an element
3976 +         * @param basis the identity (initial default value) for the reduction
3977 +         * @param reducer a commutative associative combining function
3978 +         * @return the result of accumulating the given transformation
3979 +         * of all values
3980 +         */
3981 +        public long reduceValuesToLong(ObjectToLong<? super V> transformer,
3982 +                                       long basis,
3983 +                                       LongByLongToLong reducer) {
3984 +            return fjp.invoke(ForkJoinTasks.reduceValuesToLong
3985 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3986 +        }
3987 +
3988 +        /**
3989 +         * Returns the result of accumulating the given transformation
3990 +         * of all values using the given reducer to combine values,
3991 +         * and the given basis as an identity value.
3992 +         *
3993 +         * @param transformer a function returning the transformation
3994 +         * for an element
3995 +         * @param basis the identity (initial default value) for the reduction
3996 +         * @param reducer a commutative associative combining function
3997 +         * @return the result of accumulating the given transformation
3998 +         * of all values
3999 +         */
4000 +        public int reduceValuesToInt(ObjectToInt<? super V> transformer,
4001 +                                     int basis,
4002 +                                     IntByIntToInt reducer) {
4003 +            return fjp.invoke(ForkJoinTasks.reduceValuesToInt
4004 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4005 +        }
4006 +
4007 +        /**
4008 +         * Performs the given action for each entry.
4009 +         *
4010 +         * @param action the action
4011 +         */
4012 +        public void forEachEntry(Action<Map.Entry<K,V>> action) {
4013 +            fjp.invoke(ForkJoinTasks.forEachEntry
4014 +                       (ConcurrentHashMapV8.this, action));
4015 +        }
4016 +
4017 +        /**
4018 +         * Performs the given action for each non-null transformation
4019 +         * of each entry.
4020 +         *
4021 +         * @param transformer a function returning the transformation
4022 +         * for an element, or null of there is no transformation (in
4023 +         * which case the action is not applied).
4024 +         * @param action the action
4025 +         */
4026 +        public <U> void forEachEntry(Fun<Map.Entry<K,V>, ? extends U> transformer,
4027 +                                     Action<U> action) {
4028 +            fjp.invoke(ForkJoinTasks.forEachEntry
4029 +                       (ConcurrentHashMapV8.this, transformer, action));
4030 +        }
4031 +
4032 +        /**
4033 +         * Returns a non-null result from applying the given search
4034 +         * function on each entry, or null if none.  Upon success,
4035 +         * further element processing is suppressed and the results of
4036 +         * any other parallel invocations of the search function are
4037 +         * ignored.
4038 +         *
4039 +         * @param searchFunction a function returning a non-null
4040 +         * result on success, else null
4041 +         * @return a non-null result from applying the given search
4042 +         * function on each entry, or null if none
4043 +         */
4044 +        public <U> U searchEntries(Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4045 +            return fjp.invoke(ForkJoinTasks.searchEntries
4046 +                              (ConcurrentHashMapV8.this, searchFunction));
4047 +        }
4048 +
4049 +        /**
4050 +         * Returns the result of accumulating all entries using the
4051 +         * given reducer to combine values, or null if none.
4052 +         *
4053 +         * @param reducer a commutative associative combining function
4054 +         * @return the result of accumulating all entries
4055 +         */
4056 +        public Map.Entry<K,V> reduceEntries(BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4057 +            return fjp.invoke(ForkJoinTasks.reduceEntries
4058 +                              (ConcurrentHashMapV8.this, reducer));
4059 +        }
4060 +
4061 +        /**
4062 +         * Returns the result of accumulating the given transformation
4063 +         * of all entries using the given reducer to combine values,
4064 +         * or null if none.
4065 +         *
4066 +         * @param transformer a function returning the transformation
4067 +         * for an element, or null of there is no transformation (in
4068 +         * which case it is not combined).
4069 +         * @param reducer a commutative associative combining function
4070 +         * @return the result of accumulating the given transformation
4071 +         * of all entries
4072 +         */
4073 +        public <U> U reduceEntries(Fun<Map.Entry<K,V>, ? extends U> transformer,
4074 +                                   BiFun<? super U, ? super U, ? extends U> reducer) {
4075 +            return fjp.invoke(ForkJoinTasks.reduceEntries
4076 +                              (ConcurrentHashMapV8.this, transformer, reducer));
4077 +        }
4078 +
4079 +        /**
4080 +         * Returns the result of accumulating the given transformation
4081 +         * of all entries using the given reducer to combine values,
4082 +         * and the given basis as an identity value.
4083 +         *
4084 +         * @param transformer a function returning the transformation
4085 +         * for an element
4086 +         * @param basis the identity (initial default value) for the reduction
4087 +         * @param reducer a commutative associative combining function
4088 +         * @return the result of accumulating the given transformation
4089 +         * of all entries
4090 +         */
4091 +        public double reduceEntriesToDouble(ObjectToDouble<Map.Entry<K,V>> transformer,
4092 +                                            double basis,
4093 +                                            DoubleByDoubleToDouble reducer) {
4094 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToDouble
4095 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4096 +        }
4097 +
4098 +        /**
4099 +         * Returns the result of accumulating the given transformation
4100 +         * of all entries using the given reducer to combine values,
4101 +         * and the given basis as an identity value.
4102 +         *
4103 +         * @param transformer a function returning the transformation
4104 +         * for an element
4105 +         * @param basis the identity (initial default value) for the reduction
4106 +         * @param reducer a commutative associative combining function
4107 +         * @return  the result of accumulating the given transformation
4108 +         * of all entries
4109 +         */
4110 +        public long reduceEntriesToLong(ObjectToLong<Map.Entry<K,V>> transformer,
4111 +                                        long basis,
4112 +                                        LongByLongToLong reducer) {
4113 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToLong
4114 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4115 +        }
4116 +
4117 +        /**
4118 +         * Returns the result of accumulating the given transformation
4119 +         * of all entries using the given reducer to combine values,
4120 +         * and the given basis as an identity value.
4121 +         *
4122 +         * @param transformer a function returning the transformation
4123 +         * for an element
4124 +         * @param basis the identity (initial default value) for the reduction
4125 +         * @param reducer a commutative associative combining function
4126 +         * @return the result of accumulating the given transformation
4127 +         * of all entries
4128 +         */
4129 +        public int reduceEntriesToInt(ObjectToInt<Map.Entry<K,V>> transformer,
4130 +                                      int basis,
4131 +                                      IntByIntToInt reducer) {
4132 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToInt
4133 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4134 +        }
4135 +    }
4136 +
4137 +    // ---------------------------------------------------------------------
4138 +
4139 +    /**
4140 +     * Predefined tasks for performing bulk parallel operations on
4141 +     * ConcurrentHashMaps. These tasks follow the forms and rules used
4142 +     * in class {@link Parallel}. Each method has the same name, but
4143 +     * returns a task rather than invoking it. These methods may be
4144 +     * useful in custom applications such as submitting a task without
4145 +     * waiting for completion, or combining with other tasks.
4146 +     */
4147 +    public static class ForkJoinTasks {
4148 +        private ForkJoinTasks() {}
4149 +
4150 +        /**
4151 +         * Returns a task that when invoked, performs the given
4152 +         * action for each (key, value)
4153 +         *
4154 +         * @param map the map
4155 +         * @param action the action
4156 +         * @return the task
4157 +         */
4158 +        public static <K,V> ForkJoinTask<Void> forEach
4159 +            (ConcurrentHashMapV8<K,V> map,
4160 +             BiAction<K,V> action) {
4161 +            if (action == null) throw new NullPointerException();
4162 +            return new ForEachMappingTask<K,V>(map, action);
4163 +        }
4164 +
4165 +        /**
4166 +         * Returns a task that when invoked, performs the given
4167 +         * action for each non-null transformation of each (key, value)
4168 +         *
4169 +         * @param map the map
4170 +         * @param transformer a function returning the transformation
4171 +         * for an element, or null of there is no transformation (in
4172 +         * which case the action is not applied).
4173 +         * @param action the action
4174 +         * @return the task
4175 +         */
4176 +        public static <K,V,U> ForkJoinTask<Void> forEach
4177 +            (ConcurrentHashMapV8<K,V> map,
4178 +             BiFun<? super K, ? super V, ? extends U> transformer,
4179 +             Action<U> action) {
4180 +            if (transformer == null || action == null)
4181 +                throw new NullPointerException();
4182 +            return new ForEachTransformedMappingTask<K,V,U>
4183 +                (map, transformer, action);
4184 +        }
4185 +
4186 +        /**
4187 +         * Returns a task that when invoked, returns a non-null result
4188 +         * from applying the given search function on each (key,
4189 +         * value), or null if none. Upon success, further element
4190 +         * processing is suppressed and the results of any other
4191 +         * parallel invocations of the search function are ignored.
4192 +         *
4193 +         * @param map the map
4194 +         * @param searchFunction a function returning a non-null
4195 +         * result on success, else null
4196 +         * @return the task
4197 +         */
4198 +        public static <K,V,U> ForkJoinTask<U> search
4199 +            (ConcurrentHashMapV8<K,V> map,
4200 +             BiFun<? super K, ? super V, ? extends U> searchFunction) {
4201 +            if (searchFunction == null) throw new NullPointerException();
4202 +            return new SearchMappingsTask<K,V,U>
4203 +                (map, searchFunction,
4204 +                 new AtomicReference<U>());
4205 +        }
4206 +
4207 +        /**
4208 +         * Returns a task that when invoked, returns the result of
4209 +         * accumulating the given transformation of all (key, value) pairs
4210 +         * using the given reducer to combine values, or null if none.
4211 +         *
4212 +         * @param map the map
4213 +         * @param transformer a function returning the transformation
4214 +         * for an element, or null of there is no transformation (in
4215 +         * which case it is not combined).
4216 +         * @param reducer a commutative associative combining function
4217 +         * @return the task
4218 +         */
4219 +        public static <K,V,U> ForkJoinTask<U> reduce
4220 +            (ConcurrentHashMapV8<K,V> map,
4221 +             BiFun<? super K, ? super V, ? extends U> transformer,
4222 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4223 +            if (transformer == null || reducer == null)
4224 +                throw new NullPointerException();
4225 +            return new MapReduceMappingsTask<K,V,U>
4226 +                (map, transformer, reducer);
4227 +        }
4228 +
4229 +        /**
4230 +         * Returns a task that when invoked, returns the result of
4231 +         * accumulating the given transformation of all (key, value) pairs
4232 +         * using the given reducer to combine values, and the given
4233 +         * basis as an identity value.
4234 +         *
4235 +         * @param map the map
4236 +         * @param transformer a function returning the transformation
4237 +         * for an element
4238 +         * @param basis the identity (initial default value) for the reduction
4239 +         * @param reducer a commutative associative combining function
4240 +         * @return the task
4241 +         */
4242 +        public static <K,V> ForkJoinTask<Double> reduceToDouble
4243 +            (ConcurrentHashMapV8<K,V> map,
4244 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
4245 +             double basis,
4246 +             DoubleByDoubleToDouble reducer) {
4247 +            if (transformer == null || reducer == null)
4248 +                throw new NullPointerException();
4249 +            return new MapReduceMappingsToDoubleTask<K,V>
4250 +                (map, transformer, basis, reducer);
4251 +        }
4252 +
4253 +        /**
4254 +         * Returns a task that when invoked, returns the result of
4255 +         * accumulating the given transformation of all (key, value) pairs
4256 +         * using the given reducer to combine values, and the given
4257 +         * basis as an identity value.
4258 +         *
4259 +         * @param map the map
4260 +         * @param transformer a function returning the transformation
4261 +         * for an element
4262 +         * @param basis the identity (initial default value) for the reduction
4263 +         * @param reducer a commutative associative combining function
4264 +         * @return the task
4265 +         */
4266 +        public static <K,V> ForkJoinTask<Long> reduceToLong
4267 +            (ConcurrentHashMapV8<K,V> map,
4268 +             ObjectByObjectToLong<? super K, ? super V> transformer,
4269 +             long basis,
4270 +             LongByLongToLong reducer) {
4271 +            if (transformer == null || reducer == null)
4272 +                throw new NullPointerException();
4273 +            return new MapReduceMappingsToLongTask<K,V>
4274 +                (map, transformer, basis, reducer);
4275 +        }
4276 +
4277 +        /**
4278 +         * Returns a task that when invoked, returns the result of
4279 +         * accumulating the given transformation of all (key, value) pairs
4280 +         * using the given reducer to combine values, and the given
4281 +         * basis as an identity value.
4282 +         *
4283 +         * @param transformer a function returning the transformation
4284 +         * for an element
4285 +         * @param basis the identity (initial default value) for the reduction
4286 +         * @param reducer a commutative associative combining function
4287 +         * @return the task
4288 +         */
4289 +        public static <K,V> ForkJoinTask<Integer> reduceToInt
4290 +            (ConcurrentHashMapV8<K,V> map,
4291 +             ObjectByObjectToInt<? super K, ? super V> transformer,
4292 +             int basis,
4293 +             IntByIntToInt reducer) {
4294 +            if (transformer == null || reducer == null)
4295 +                throw new NullPointerException();
4296 +            return new MapReduceMappingsToIntTask<K,V>
4297 +                (map, transformer, basis, reducer);
4298 +        }
4299 +
4300 +        /**
4301 +         * Returns a task that when invoked, performs the given action
4302 +         * for each key.
4303 +         *
4304 +         * @param map the map
4305 +         * @param action the action
4306 +         * @return the task
4307 +         */
4308 +        public static <K,V> ForkJoinTask<Void> forEachKey
4309 +            (ConcurrentHashMapV8<K,V> map,
4310 +             Action<K> action) {
4311 +            if (action == null) throw new NullPointerException();
4312 +            return new ForEachKeyTask<K,V>(map, action);
4313 +        }
4314 +
4315 +        /**
4316 +         * Returns a task that when invoked, performs the given action
4317 +         * for each non-null transformation of each key.
4318 +         *
4319 +         * @param map the map
4320 +         * @param transformer a function returning the transformation
4321 +         * for an element, or null of there is no transformation (in
4322 +         * which case the action is not applied).
4323 +         * @param action the action
4324 +         * @return the task
4325 +         */
4326 +        public static <K,V,U> ForkJoinTask<Void> forEachKey
4327 +            (ConcurrentHashMapV8<K,V> map,
4328 +             Fun<? super K, ? extends U> transformer,
4329 +             Action<U> action) {
4330 +            if (transformer == null || action == null)
4331 +                throw new NullPointerException();
4332 +            return new ForEachTransformedKeyTask<K,V,U>
4333 +                (map, transformer, action);
4334 +        }
4335 +
4336 +        /**
4337 +         * Returns a task that when invoked, returns a non-null result
4338 +         * from applying the given search function on each key, or
4339 +         * null if none.  Upon success, further element processing is
4340 +         * suppressed and the results of any other parallel
4341 +         * invocations of the search function are ignored.
4342 +         *
4343 +         * @param map the map
4344 +         * @param searchFunction a function returning a non-null
4345 +         * result on success, else null
4346 +         * @return the task
4347 +         */
4348 +        public static <K,V,U> ForkJoinTask<U> searchKeys
4349 +            (ConcurrentHashMapV8<K,V> map,
4350 +             Fun<? super K, ? extends U> searchFunction) {
4351 +            if (searchFunction == null) throw new NullPointerException();
4352 +            return new SearchKeysTask<K,V,U>
4353 +                (map, searchFunction,
4354 +                 new AtomicReference<U>());
4355 +        }
4356 +
4357 +        /**
4358 +         * Returns a task that when invoked, returns the result of
4359 +         * accumulating all keys using the given reducer to combine
4360 +         * values, or null if none.
4361 +         *
4362 +         * @param map the map
4363 +         * @param reducer a commutative associative combining function
4364 +         * @return the task
4365 +         */
4366 +        public static <K,V> ForkJoinTask<K> reduceKeys
4367 +            (ConcurrentHashMapV8<K,V> map,
4368 +             BiFun<? super K, ? super K, ? extends K> reducer) {
4369 +            if (reducer == null) throw new NullPointerException();
4370 +            return new ReduceKeysTask<K,V>
4371 +                (map, reducer);
4372 +        }
4373 +
4374 +        /**
4375 +         * Returns a task that when invoked, returns the result of
4376 +         * accumulating the given transformation of all keys using the given
4377 +         * reducer to combine values, or null if none.
4378 +         *
4379 +         * @param map the map
4380 +         * @param transformer a function returning the transformation
4381 +         * for an element, or null of there is no transformation (in
4382 +         * which case it is not combined).
4383 +         * @param reducer a commutative associative combining function
4384 +         * @return the task
4385 +         */
4386 +        public static <K,V,U> ForkJoinTask<U> reduceKeys
4387 +            (ConcurrentHashMapV8<K,V> map,
4388 +             Fun<? super K, ? extends U> transformer,
4389 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4390 +            if (transformer == null || reducer == null)
4391 +                throw new NullPointerException();
4392 +            return new MapReduceKeysTask<K,V,U>
4393 +                (map, transformer, reducer);
4394 +        }
4395 +
4396 +        /**
4397 +         * Returns a task that when invoked, returns the result of
4398 +         * accumulating the given transformation of all keys using the given
4399 +         * reducer to combine values, and the given basis as an
4400 +         * identity value.
4401 +         *
4402 +         * @param map the map
4403 +         * @param transformer a function returning the transformation
4404 +         * for an element
4405 +         * @param basis the identity (initial default value) for the reduction
4406 +         * @param reducer a commutative associative combining function
4407 +         * @return the task
4408 +         */
4409 +        public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
4410 +            (ConcurrentHashMapV8<K,V> map,
4411 +             ObjectToDouble<? super K> transformer,
4412 +             double basis,
4413 +             DoubleByDoubleToDouble reducer) {
4414 +            if (transformer == null || reducer == null)
4415 +                throw new NullPointerException();
4416 +            return new MapReduceKeysToDoubleTask<K,V>
4417 +                (map, transformer, basis, reducer);
4418 +        }
4419 +
4420 +        /**
4421 +         * Returns a task that when invoked, returns the result of
4422 +         * accumulating the given transformation of all keys using the given
4423 +         * reducer to combine values, and the given basis as an
4424 +         * identity value.
4425 +         *
4426 +         * @param map the map
4427 +         * @param transformer a function returning the transformation
4428 +         * for an element
4429 +         * @param basis the identity (initial default value) for the reduction
4430 +         * @param reducer a commutative associative combining function
4431 +         * @return the task
4432 +         */
4433 +        public static <K,V> ForkJoinTask<Long> reduceKeysToLong
4434 +            (ConcurrentHashMapV8<K,V> map,
4435 +             ObjectToLong<? super K> transformer,
4436 +             long basis,
4437 +             LongByLongToLong reducer) {
4438 +            if (transformer == null || reducer == null)
4439 +                throw new NullPointerException();
4440 +            return new MapReduceKeysToLongTask<K,V>
4441 +                (map, transformer, basis, reducer);
4442 +        }
4443 +
4444 +        /**
4445 +         * Returns a task that when invoked, returns the result of
4446 +         * accumulating the given transformation of all keys using the given
4447 +         * reducer to combine values, and the given basis as an
4448 +         * identity value.
4449 +         *
4450 +         * @param map the map
4451 +         * @param transformer a function returning the transformation
4452 +         * for an element
4453 +         * @param basis the identity (initial default value) for the reduction
4454 +         * @param reducer a commutative associative combining function
4455 +         * @return the task
4456 +         */
4457 +        public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
4458 +            (ConcurrentHashMapV8<K,V> map,
4459 +             ObjectToInt<? super K> transformer,
4460 +             int basis,
4461 +             IntByIntToInt reducer) {
4462 +            if (transformer == null || reducer == null)
4463 +                throw new NullPointerException();
4464 +            return new MapReduceKeysToIntTask<K,V>
4465 +                (map, transformer, basis, reducer);
4466 +        }
4467 +
4468 +        /**
4469 +         * Returns a task that when invoked, performs the given action
4470 +         * for each value.
4471 +         *
4472 +         * @param map the map
4473 +         * @param action the action
4474 +         */
4475 +        public static <K,V> ForkJoinTask<Void> forEachValue
4476 +            (ConcurrentHashMapV8<K,V> map,
4477 +             Action<V> action) {
4478 +            if (action == null) throw new NullPointerException();
4479 +            return new ForEachValueTask<K,V>(map, action);
4480 +        }
4481 +
4482 +        /**
4483 +         * Returns a task that when invoked, performs the given action
4484 +         * for each non-null transformation of each value.
4485 +         *
4486 +         * @param map the map
4487 +         * @param transformer a function returning the transformation
4488 +         * for an element, or null of there is no transformation (in
4489 +         * which case the action is not applied).
4490 +         * @param action the action
4491 +         */
4492 +        public static <K,V,U> ForkJoinTask<Void> forEachValue
4493 +            (ConcurrentHashMapV8<K,V> map,
4494 +             Fun<? super V, ? extends U> transformer,
4495 +             Action<U> action) {
4496 +            if (transformer == null || action == null)
4497 +                throw new NullPointerException();
4498 +            return new ForEachTransformedValueTask<K,V,U>
4499 +                (map, transformer, action);
4500 +        }
4501 +
4502 +        /**
4503 +         * Returns a task that when invoked, returns a non-null result
4504 +         * from applying the given search function on each value, or
4505 +         * null if none.  Upon success, further element processing is
4506 +         * suppressed and the results of any other parallel
4507 +         * invocations of the search function are ignored.
4508 +         *
4509 +         * @param map the map
4510 +         * @param searchFunction a function returning a non-null
4511 +         * result on success, else null
4512 +         * @return the task
4513 +         *
4514 +         */
4515 +        public static <K,V,U> ForkJoinTask<U> searchValues
4516 +            (ConcurrentHashMapV8<K,V> map,
4517 +             Fun<? super V, ? extends U> searchFunction) {
4518 +            if (searchFunction == null) throw new NullPointerException();
4519 +            return new SearchValuesTask<K,V,U>
4520 +                (map, searchFunction,
4521 +                 new AtomicReference<U>());
4522 +        }
4523 +
4524 +        /**
4525 +         * Returns a task that when invoked, returns the result of
4526 +         * accumulating all values using the given reducer to combine
4527 +         * values, or null if none.
4528 +         *
4529 +         * @param map the map
4530 +         * @param reducer a commutative associative combining function
4531 +         * @return the task
4532 +         */
4533 +        public static <K,V> ForkJoinTask<V> reduceValues
4534 +            (ConcurrentHashMapV8<K,V> map,
4535 +             BiFun<? super V, ? super V, ? extends V> reducer) {
4536 +            if (reducer == null) throw new NullPointerException();
4537 +            return new ReduceValuesTask<K,V>
4538 +                (map, reducer);
4539 +        }
4540 +
4541 +        /**
4542 +         * Returns a task that when invoked, returns the result of
4543 +         * accumulating the given transformation of all values using the
4544 +         * given reducer to combine values, or null if none.
4545 +         *
4546 +         * @param map the map
4547 +         * @param transformer a function returning the transformation
4548 +         * for an element, or null of there is no transformation (in
4549 +         * which case it is not combined).
4550 +         * @param reducer a commutative associative combining function
4551 +         * @return the task
4552 +         */
4553 +        public static <K,V,U> ForkJoinTask<U> reduceValues
4554 +            (ConcurrentHashMapV8<K,V> map,
4555 +             Fun<? super V, ? extends U> transformer,
4556 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4557 +            if (transformer == null || reducer == null)
4558 +                throw new NullPointerException();
4559 +            return new MapReduceValuesTask<K,V,U>
4560 +                (map, transformer, reducer);
4561 +        }
4562 +
4563 +        /**
4564 +         * Returns a task that when invoked, returns the result of
4565 +         * accumulating the given transformation of all values using the
4566 +         * given reducer to combine values, and the given basis as an
4567 +         * identity value.
4568 +         *
4569 +         * @param map the map
4570 +         * @param transformer a function returning the transformation
4571 +         * for an element
4572 +         * @param basis the identity (initial default value) for the reduction
4573 +         * @param reducer a commutative associative combining function
4574 +         * @return the task
4575 +         */
4576 +        public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
4577 +            (ConcurrentHashMapV8<K,V> map,
4578 +             ObjectToDouble<? super V> transformer,
4579 +             double basis,
4580 +             DoubleByDoubleToDouble reducer) {
4581 +            if (transformer == null || reducer == null)
4582 +                throw new NullPointerException();
4583 +            return new MapReduceValuesToDoubleTask<K,V>
4584 +                (map, transformer, basis, reducer);
4585 +        }
4586 +
4587 +        /**
4588 +         * Returns a task that when invoked, returns the result of
4589 +         * accumulating the given transformation of all values using the
4590 +         * given reducer to combine values, and the given basis as an
4591 +         * identity value.
4592 +         *
4593 +         * @param map the map
4594 +         * @param transformer a function returning the transformation
4595 +         * for an element
4596 +         * @param basis the identity (initial default value) for the reduction
4597 +         * @param reducer a commutative associative combining function
4598 +         * @return the task
4599 +         */
4600 +        public static <K,V> ForkJoinTask<Long> reduceValuesToLong
4601 +            (ConcurrentHashMapV8<K,V> map,
4602 +             ObjectToLong<? super V> transformer,
4603 +             long basis,
4604 +             LongByLongToLong reducer) {
4605 +            if (transformer == null || reducer == null)
4606 +                throw new NullPointerException();
4607 +            return new MapReduceValuesToLongTask<K,V>
4608 +                (map, transformer, basis, reducer);
4609 +        }
4610 +
4611 +        /**
4612 +         * Returns a task that when invoked, returns the result of
4613 +         * accumulating the given transformation of all values using the
4614 +         * given reducer to combine values, and the given basis as an
4615 +         * identity value.
4616 +         *
4617 +         * @param map the map
4618 +         * @param transformer a function returning the transformation
4619 +         * for an element
4620 +         * @param basis the identity (initial default value) for the reduction
4621 +         * @param reducer a commutative associative combining function
4622 +         * @return the task
4623 +         */
4624 +        public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
4625 +            (ConcurrentHashMapV8<K,V> map,
4626 +             ObjectToInt<? super V> transformer,
4627 +             int basis,
4628 +             IntByIntToInt reducer) {
4629 +            if (transformer == null || reducer == null)
4630 +                throw new NullPointerException();
4631 +            return new MapReduceValuesToIntTask<K,V>
4632 +                (map, transformer, basis, reducer);
4633 +        }
4634 +
4635 +        /**
4636 +         * Returns a task that when invoked, perform the given action
4637 +         * for each entry.
4638 +         *
4639 +         * @param map the map
4640 +         * @param action the action
4641 +         */
4642 +        public static <K,V> ForkJoinTask<Void> forEachEntry
4643 +            (ConcurrentHashMapV8<K,V> map,
4644 +             Action<Map.Entry<K,V>> action) {
4645 +            if (action == null) throw new NullPointerException();
4646 +            return new ForEachEntryTask<K,V>(map, action);
4647 +        }
4648 +
4649 +        /**
4650 +         * Returns a task that when invoked, perform the given action
4651 +         * for each non-null transformation of each entry.
4652 +         *
4653 +         * @param map the map
4654 +         * @param transformer a function returning the transformation
4655 +         * for an element, or null of there is no transformation (in
4656 +         * which case the action is not applied).
4657 +         * @param action the action
4658 +         */
4659 +        public static <K,V,U> ForkJoinTask<Void> forEachEntry
4660 +            (ConcurrentHashMapV8<K,V> map,
4661 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
4662 +             Action<U> action) {
4663 +            if (transformer == null || action == null)
4664 +                throw new NullPointerException();
4665 +            return new ForEachTransformedEntryTask<K,V,U>
4666 +                (map, transformer, action);
4667 +        }
4668 +
4669 +        /**
4670 +         * Returns a task that when invoked, returns a non-null result
4671 +         * from applying the given search function on each entry, or
4672 +         * null if none.  Upon success, further element processing is
4673 +         * suppressed and the results of any other parallel
4674 +         * invocations of the search function are ignored.
4675 +         *
4676 +         * @param map the map
4677 +         * @param searchFunction a function returning a non-null
4678 +         * result on success, else null
4679 +         * @return the task
4680 +         *
4681 +         */
4682 +        public static <K,V,U> ForkJoinTask<U> searchEntries
4683 +            (ConcurrentHashMapV8<K,V> map,
4684 +             Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4685 +            if (searchFunction == null) throw new NullPointerException();
4686 +            return new SearchEntriesTask<K,V,U>
4687 +                (map, searchFunction,
4688 +                 new AtomicReference<U>());
4689 +        }
4690 +
4691 +        /**
4692 +         * Returns a task that when invoked, returns the result of
4693 +         * accumulating all entries using the given reducer to combine
4694 +         * values, or null if none.
4695 +         *
4696 +         * @param map the map
4697 +         * @param reducer a commutative associative combining function
4698 +         * @return the task
4699 +         */
4700 +        public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
4701 +            (ConcurrentHashMapV8<K,V> map,
4702 +             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4703 +            if (reducer == null) throw new NullPointerException();
4704 +            return new ReduceEntriesTask<K,V>
4705 +                (map, reducer);
4706 +        }
4707 +
4708 +        /**
4709 +         * Returns a task that when invoked, returns the result of
4710 +         * accumulating the given transformation of all entries using the
4711 +         * given reducer to combine values, or null if none.
4712 +         *
4713 +         * @param map the map
4714 +         * @param transformer a function returning the transformation
4715 +         * for an element, or null of there is no transformation (in
4716 +         * which case it is not combined).
4717 +         * @param reducer a commutative associative combining function
4718 +         * @return the task
4719 +         */
4720 +        public static <K,V,U> ForkJoinTask<U> reduceEntries
4721 +            (ConcurrentHashMapV8<K,V> map,
4722 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
4723 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4724 +            if (transformer == null || reducer == null)
4725 +                throw new NullPointerException();
4726 +            return new MapReduceEntriesTask<K,V,U>
4727 +                (map, transformer, reducer);
4728 +        }
4729 +
4730 +        /**
4731 +         * Returns a task that when invoked, returns the result of
4732 +         * accumulating the given transformation of all entries using the
4733 +         * given reducer to combine values, and the given basis as an
4734 +         * identity value.
4735 +         *
4736 +         * @param map the map
4737 +         * @param transformer a function returning the transformation
4738 +         * for an element
4739 +         * @param basis the identity (initial default value) for the reduction
4740 +         * @param reducer a commutative associative combining function
4741 +         * @return the task
4742 +         */
4743 +        public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
4744 +            (ConcurrentHashMapV8<K,V> map,
4745 +             ObjectToDouble<Map.Entry<K,V>> transformer,
4746 +             double basis,
4747 +             DoubleByDoubleToDouble reducer) {
4748 +            if (transformer == null || reducer == null)
4749 +                throw new NullPointerException();
4750 +            return new MapReduceEntriesToDoubleTask<K,V>
4751 +                (map, transformer, basis, reducer);
4752 +        }
4753 +
4754 +        /**
4755 +         * Returns a task that when invoked, returns the result of
4756 +         * accumulating the given transformation of all entries using the
4757 +         * given reducer to combine values, and the given basis as an
4758 +         * identity value.
4759 +         *
4760 +         * @param map the map
4761 +         * @param transformer a function returning the transformation
4762 +         * for an element
4763 +         * @param basis the identity (initial default value) for the reduction
4764 +         * @param reducer a commutative associative combining function
4765 +         * @return the task
4766 +         */
4767 +        public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
4768 +            (ConcurrentHashMapV8<K,V> map,
4769 +             ObjectToLong<Map.Entry<K,V>> transformer,
4770 +             long basis,
4771 +             LongByLongToLong reducer) {
4772 +            if (transformer == null || reducer == null)
4773 +                throw new NullPointerException();
4774 +            return new MapReduceEntriesToLongTask<K,V>
4775 +                (map, transformer, basis, reducer);
4776 +        }
4777 +
4778 +        /**
4779 +         * Returns a task that when invoked, returns the result of
4780 +         * accumulating the given transformation of all entries using the
4781 +         * given reducer to combine values, and the given basis as an
4782 +         * identity value.
4783 +         *
4784 +         * @param map the map
4785 +         * @param transformer a function returning the transformation
4786 +         * for an element
4787 +         * @param basis the identity (initial default value) for the reduction
4788 +         * @param reducer a commutative associative combining function
4789 +         * @return the task
4790 +         */
4791 +        public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
4792 +            (ConcurrentHashMapV8<K,V> map,
4793 +             ObjectToInt<Map.Entry<K,V>> transformer,
4794 +             int basis,
4795 +             IntByIntToInt reducer) {
4796 +            if (transformer == null || reducer == null)
4797 +                throw new NullPointerException();
4798 +            return new MapReduceEntriesToIntTask<K,V>
4799 +                (map, transformer, basis, reducer);
4800 +        }
4801 +    }
4802 +
4803 +    // -------------------------------------------------------
4804 +
4805 +    /**
4806 +     * Base for FJ tasks for bulk operations. This adds a variant of
4807 +     * CountedCompleters and some split and merge bookkeeping to
4808 +     * iterator functionality. The forEach and reduce methods are
4809 +     * similar to those illustrated in CountedCompleter documentation,
4810 +     * except that bottom-up reduction completions perform them within
4811 +     * their compute methods. The search methods are like forEach
4812 +     * except they continually poll for success and exit early.  Also,
4813 +     * exceptions are handled in a simpler manner, by just trying to
4814 +     * complete root task exceptionally.
4815 +     */
4816 +    @SuppressWarnings("serial") static abstract class BulkTask<K,V,R> extends Traverser<K,V,R> {
4817 +        final BulkTask<K,V,?> parent;  // completion target
4818 +        int batch;                     // split control
4819 +        int pending;                   // completion control
4820 +
4821 +        /** Constructor for root tasks */
4822 +        BulkTask(ConcurrentHashMapV8<K,V> map) {
4823 +            super(map);
4824 +            this.parent = null;
4825 +            this.batch = -1; // force call to batch() on execution
4826 +        }
4827 +
4828 +        /** Constructor for subtasks */
4829 +        BulkTask(BulkTask<K,V,?> parent, int batch) {
4830 +            super(parent);
4831 +            this.parent = parent;
4832 +            this.batch = batch;
4833 +        }
4834 +
4835 +        // FJ methods
4836 +
4837 +        /**
4838 +         * Propagates completion. Note that all reduce actions
4839 +         * bypass this method to combine while completing.
4840 +         */
4841 +        final void tryComplete() {
4842 +            BulkTask<K,V,?> a = this, s = a;
4843 +            for (int c;;) {
4844 +                if ((c = a.pending) == 0) {
4845 +                    if ((a = (s = a).parent) == null) {
4846 +                        s.quietlyComplete();
4847 +                        break;
4848 +                    }
4849 +                }
4850 +                else if (U.compareAndSwapInt(a, PENDING, c, c - 1))
4851 +                    break;
4852 +            }
4853 +        }
4854 +
4855 +        /**
4856 +         * Forces root task to complete.
4857 +         * @param ex if null, complete normally, else exceptionally
4858 +         * @return false to simplify use
4859 +         */
4860 +        final boolean tryCompleteComputation(Throwable ex) {
4861 +            for (BulkTask<K,V,?> a = this;;) {
4862 +                BulkTask<K,V,?> p = a.parent;
4863 +                if (p == null) {
4864 +                    if (ex != null)
4865 +                        a.completeExceptionally(ex);
4866 +                    else
4867 +                        a.quietlyComplete();
4868 +                    return false;
4869 +                }
4870 +                a = p;
4871 +            }
4872 +        }
4873 +
4874 +        /**
4875 +         * Version of tryCompleteComputation for function screening checks
4876 +         */
4877 +        final boolean abortOnNullFunction() {
4878 +            return tryCompleteComputation(new Error("Unexpected null function"));
4879 +        }
4880 +
4881 +        // utilities
4882 +
4883 +        /** CompareAndSet pending count */
4884 +        final boolean casPending(int cmp, int val) {
4885 +            return U.compareAndSwapInt(this, PENDING, cmp, val);
4886 +        }
4887 +
4888 +        /**
4889 +         * Returns approx exp2 of the number of times (minus one) to
4890 +         * split task by two before executing leaf action. This value
4891 +         * is faster to compute and more convenient to use as a guide
4892 +         * to splitting than is the depth, since it is used while
4893 +         * dividing by two anyway.
4894 +         */
4895 +        final int batch() {
4896 +            int b = batch;
4897 +            if (b < 0) {
4898 +                long n = map.counter.sum();
4899 +                int sp = getPool().getParallelism() << 3; // slack of 8
4900 +                b = batch = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
4901 +            }
4902 +            return b;
4903 +        }
4904 +
4905 +        /**
4906 +         * Returns exportable snapshot entry.
4907 +         */
4908 +        static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
4909 +            return new AbstractMap.SimpleEntry<K,V>(k, v);
4910 +        }
4911 +
4912 +        // Unsafe mechanics
4913 +        private static final sun.misc.Unsafe U;
4914 +        private static final long PENDING;
4915 +        static {
4916 +            try {
4917 +                U = getUnsafe();
4918 +                PENDING = U.objectFieldOffset
4919 +                    (BulkTask.class.getDeclaredField("pending"));
4920 +            } catch (Exception e) {
4921 +                throw new Error(e);
4922 +            }
4923 +        }
4924 +    }
4925 +
4926 +    /*
4927 +     * Task classes. Coded in a regular but ugly format/style to
4928 +     * simplify checks that each variant differs in the right way from
4929 +     * others.
4930 +     */
4931 +
4932 +    @SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
4933 +        extends BulkTask<K,V,Void> {
4934 +        final Action<K> action;
4935 +        ForEachKeyTask
4936 +            (ConcurrentHashMapV8<K,V> m,
4937 +             Action<K> action) {
4938 +            super(m);
4939 +            this.action = action;
4940 +        }
4941 +        ForEachKeyTask
4942 +            (BulkTask<K,V,?> p, int b,
4943 +             Action<K> action) {
4944 +            super(p, b);
4945 +            this.action = action;
4946 +        }
4947 +        @SuppressWarnings("unchecked") public final boolean exec() {
4948 +            final Action<K> action = this.action;
4949 +            if (action == null)
4950 +                return abortOnNullFunction();
4951 +            try {
4952 +                int b = batch(), c;
4953 +                while (b > 1 && baseIndex != baseLimit) {
4954 +                    do {} while (!casPending(c = pending, c+1));
4955 +                    new ForEachKeyTask<K,V>(this, b >>>= 1, action).fork();
4956 +                }
4957 +                while (advance() != null)
4958 +                    action.apply((K)nextKey);
4959 +                tryComplete();
4960 +            } catch (Throwable ex) {
4961 +                return tryCompleteComputation(ex);
4962 +            }
4963 +            return false;
4964 +        }
4965 +    }
4966 +
4967 +    @SuppressWarnings("serial") static final class ForEachValueTask<K,V>
4968 +        extends BulkTask<K,V,Void> {
4969 +        final Action<V> action;
4970 +        ForEachValueTask
4971 +            (ConcurrentHashMapV8<K,V> m,
4972 +             Action<V> action) {
4973 +            super(m);
4974 +            this.action = action;
4975 +        }
4976 +        ForEachValueTask
4977 +            (BulkTask<K,V,?> p, int b,
4978 +             Action<V> action) {
4979 +            super(p, b);
4980 +            this.action = action;
4981 +        }
4982 +        @SuppressWarnings("unchecked") public final boolean exec() {
4983 +            final Action<V> action = this.action;
4984 +            if (action == null)
4985 +                return abortOnNullFunction();
4986 +            try {
4987 +                int b = batch(), c;
4988 +                while (b > 1 && baseIndex != baseLimit) {
4989 +                    do {} while (!casPending(c = pending, c+1));
4990 +                    new ForEachValueTask<K,V>(this, b >>>= 1, action).fork();
4991 +                }
4992 +                Object v;
4993 +                while ((v = advance()) != null)
4994 +                    action.apply((V)v);
4995 +                tryComplete();
4996 +            } catch (Throwable ex) {
4997 +                return tryCompleteComputation(ex);
4998 +            }
4999 +            return false;
5000 +        }
5001 +    }
5002 +
5003 +    @SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5004 +        extends BulkTask<K,V,Void> {
5005 +        final Action<Entry<K,V>> action;
5006 +        ForEachEntryTask
5007 +            (ConcurrentHashMapV8<K,V> m,
5008 +             Action<Entry<K,V>> action) {
5009 +            super(m);
5010 +            this.action = action;
5011 +        }
5012 +        ForEachEntryTask
5013 +            (BulkTask<K,V,?> p, int b,
5014 +             Action<Entry<K,V>> action) {
5015 +            super(p, b);
5016 +            this.action = action;
5017 +        }
5018 +        @SuppressWarnings("unchecked") public final boolean exec() {
5019 +            final Action<Entry<K,V>> action = this.action;
5020 +            if (action == null)
5021 +                return abortOnNullFunction();
5022 +            try {
5023 +                int b = batch(), c;
5024 +                while (b > 1 && baseIndex != baseLimit) {
5025 +                    do {} while (!casPending(c = pending, c+1));
5026 +                    new ForEachEntryTask<K,V>(this, b >>>= 1, action).fork();
5027 +                }
5028 +                Object v;
5029 +                while ((v = advance()) != null)
5030 +                    action.apply(entryFor((K)nextKey, (V)v));
5031 +                tryComplete();
5032 +            } catch (Throwable ex) {
5033 +                return tryCompleteComputation(ex);
5034 +            }
5035 +            return false;
5036 +        }
5037 +    }
5038 +
5039 +    @SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5040 +        extends BulkTask<K,V,Void> {
5041 +        final BiAction<K,V> action;
5042 +        ForEachMappingTask
5043 +            (ConcurrentHashMapV8<K,V> m,
5044 +             BiAction<K,V> action) {
5045 +            super(m);
5046 +            this.action = action;
5047 +        }
5048 +        ForEachMappingTask
5049 +            (BulkTask<K,V,?> p, int b,
5050 +             BiAction<K,V> action) {
5051 +            super(p, b);
5052 +            this.action = action;
5053 +        }
5054 +
5055 +        @SuppressWarnings("unchecked") public final boolean exec() {
5056 +            final BiAction<K,V> action = this.action;
5057 +            if (action == null)
5058 +                return abortOnNullFunction();
5059 +            try {
5060 +                int b = batch(), c;
5061 +                while (b > 1 && baseIndex != baseLimit) {
5062 +                    do {} while (!casPending(c = pending, c+1));
5063 +                    new ForEachMappingTask<K,V>(this, b >>>= 1,
5064 +                                                action).fork();
5065 +                }
5066 +                Object v;
5067 +                while ((v = advance()) != null)
5068 +                    action.apply((K)nextKey, (V)v);
5069 +                tryComplete();
5070 +            } catch (Throwable ex) {
5071 +                return tryCompleteComputation(ex);
5072 +            }
5073 +            return false;
5074 +        }
5075 +    }
5076 +
5077 +    @SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5078 +        extends BulkTask<K,V,Void> {
5079 +        final Fun<? super K, ? extends U> transformer;
5080 +        final Action<U> action;
5081 +        ForEachTransformedKeyTask
5082 +            (ConcurrentHashMapV8<K,V> m,
5083 +             Fun<? super K, ? extends U> transformer,
5084 +             Action<U> action) {
5085 +            super(m);
5086 +            this.transformer = transformer;
5087 +            this.action = action;
5088 +
5089 +        }
5090 +        ForEachTransformedKeyTask
5091 +            (BulkTask<K,V,?> p, int b,
5092 +             Fun<? super K, ? extends U> transformer,
5093 +             Action<U> action) {
5094 +            super(p, b);
5095 +            this.transformer = transformer;
5096 +            this.action = action;
5097 +        }
5098 +        @SuppressWarnings("unchecked") public final boolean exec() {
5099 +            final Fun<? super K, ? extends U> transformer =
5100 +                this.transformer;
5101 +            final Action<U> action = this.action;
5102 +            if (transformer == null || action == null)
5103 +                return abortOnNullFunction();
5104 +            try {
5105 +                int b = batch(), c;
5106 +                while (b > 1 && baseIndex != baseLimit) {
5107 +                    do {} while (!casPending(c = pending, c+1));
5108 +                    new ForEachTransformedKeyTask<K,V,U>
5109 +                        (this, b >>>= 1, transformer, action).fork();
5110 +                }
5111 +                U u;
5112 +                while (advance() != null) {
5113 +                    if ((u = transformer.apply((K)nextKey)) != null)
5114 +                        action.apply(u);
5115 +                }
5116 +                tryComplete();
5117 +            } catch (Throwable ex) {
5118 +                return tryCompleteComputation(ex);
5119 +            }
5120 +            return false;
5121 +        }
5122 +    }
5123 +
5124 +    @SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5125 +        extends BulkTask<K,V,Void> {
5126 +        final Fun<? super V, ? extends U> transformer;
5127 +        final Action<U> action;
5128 +        ForEachTransformedValueTask
5129 +            (ConcurrentHashMapV8<K,V> m,
5130 +             Fun<? super V, ? extends U> transformer,
5131 +             Action<U> action) {
5132 +            super(m);
5133 +            this.transformer = transformer;
5134 +            this.action = action;
5135 +
5136 +        }
5137 +        ForEachTransformedValueTask
5138 +            (BulkTask<K,V,?> p, int b,
5139 +             Fun<? super V, ? extends U> transformer,
5140 +             Action<U> action) {
5141 +            super(p, b);
5142 +            this.transformer = transformer;
5143 +            this.action = action;
5144 +        }
5145 +        @SuppressWarnings("unchecked") public final boolean exec() {
5146 +            final Fun<? super V, ? extends U> transformer =
5147 +                this.transformer;
5148 +            final Action<U> action = this.action;
5149 +            if (transformer == null || action == null)
5150 +                return abortOnNullFunction();
5151 +            try {
5152 +                int b = batch(), c;
5153 +                while (b > 1 && baseIndex != baseLimit) {
5154 +                    do {} while (!casPending(c = pending, c+1));
5155 +                    new ForEachTransformedValueTask<K,V,U>
5156 +                        (this, b >>>= 1, transformer, action).fork();
5157 +                }
5158 +                Object v; U u;
5159 +                while ((v = advance()) != null) {
5160 +                    if ((u = transformer.apply((V)v)) != null)
5161 +                        action.apply(u);
5162 +                }
5163 +                tryComplete();
5164 +            } catch (Throwable ex) {
5165 +                return tryCompleteComputation(ex);
5166 +            }
5167 +            return false;
5168 +        }
5169 +    }
5170 +
5171 +    @SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5172 +        extends BulkTask<K,V,Void> {
5173 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5174 +        final Action<U> action;
5175 +        ForEachTransformedEntryTask
5176 +            (ConcurrentHashMapV8<K,V> m,
5177 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5178 +             Action<U> action) {
5179 +            super(m);
5180 +            this.transformer = transformer;
5181 +            this.action = action;
5182 +
5183 +        }
5184 +        ForEachTransformedEntryTask
5185 +            (BulkTask<K,V,?> p, int b,
5186 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5187 +             Action<U> action) {
5188 +            super(p, b);
5189 +            this.transformer = transformer;
5190 +            this.action = action;
5191 +        }
5192 +        @SuppressWarnings("unchecked") public final boolean exec() {
5193 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5194 +                this.transformer;
5195 +            final Action<U> action = this.action;
5196 +            if (transformer == null || action == null)
5197 +                return abortOnNullFunction();
5198 +            try {
5199 +                int b = batch(), c;
5200 +                while (b > 1 && baseIndex != baseLimit) {
5201 +                    do {} while (!casPending(c = pending, c+1));
5202 +                    new ForEachTransformedEntryTask<K,V,U>
5203 +                        (this, b >>>= 1, transformer, action).fork();
5204 +                }
5205 +                Object v; U u;
5206 +                while ((v = advance()) != null) {
5207 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5208 +                        action.apply(u);
5209 +                }
5210 +                tryComplete();
5211 +            } catch (Throwable ex) {
5212 +                return tryCompleteComputation(ex);
5213 +            }
5214 +            return false;
5215 +        }
5216 +    }
5217 +
5218 +    @SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5219 +        extends BulkTask<K,V,Void> {
5220 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5221 +        final Action<U> action;
5222 +        ForEachTransformedMappingTask
5223 +            (ConcurrentHashMapV8<K,V> m,
5224 +             BiFun<? super K, ? super V, ? extends U> transformer,
5225 +             Action<U> action) {
5226 +            super(m);
5227 +            this.transformer = transformer;
5228 +            this.action = action;
5229 +
5230 +        }
5231 +        ForEachTransformedMappingTask
5232 +            (BulkTask<K,V,?> p, int b,
5233 +             BiFun<? super K, ? super V, ? extends U> transformer,
5234 +             Action<U> action) {
5235 +            super(p, b);
5236 +            this.transformer = transformer;
5237 +            this.action = action;
5238 +        }
5239 +        @SuppressWarnings("unchecked") public final boolean exec() {
5240 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5241 +                this.transformer;
5242 +            final Action<U> action = this.action;
5243 +            if (transformer == null || action == null)
5244 +                return abortOnNullFunction();
5245 +            try {
5246 +                int b = batch(), c;
5247 +                while (b > 1 && baseIndex != baseLimit) {
5248 +                    do {} while (!casPending(c = pending, c+1));
5249 +                    new ForEachTransformedMappingTask<K,V,U>
5250 +                        (this, b >>>= 1, transformer, action).fork();
5251 +                }
5252 +                Object v; U u;
5253 +                while ((v = advance()) != null) {
5254 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5255 +                        action.apply(u);
5256 +                }
5257 +                tryComplete();
5258 +            } catch (Throwable ex) {
5259 +                return tryCompleteComputation(ex);
5260 +            }
5261 +            return false;
5262 +        }
5263 +    }
5264 +
5265 +    @SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5266 +        extends BulkTask<K,V,U> {
5267 +        final Fun<? super K, ? extends U> searchFunction;
5268 +        final AtomicReference<U> result;
5269 +        SearchKeysTask
5270 +            (ConcurrentHashMapV8<K,V> m,
5271 +             Fun<? super K, ? extends U> searchFunction,
5272 +             AtomicReference<U> result) {
5273 +            super(m);
5274 +            this.searchFunction = searchFunction; this.result = result;
5275 +        }
5276 +        SearchKeysTask
5277 +            (BulkTask<K,V,?> p, int b,
5278 +             Fun<? super K, ? extends U> searchFunction,
5279 +             AtomicReference<U> result) {
5280 +            super(p, b);
5281 +            this.searchFunction = searchFunction; this.result = result;
5282 +        }
5283 +        @SuppressWarnings("unchecked") public final boolean exec() {
5284 +            AtomicReference<U> result = this.result;
5285 +            final Fun<? super K, ? extends U> searchFunction =
5286 +                this.searchFunction;
5287 +            if (searchFunction == null || result == null)
5288 +                return abortOnNullFunction();
5289 +            try {
5290 +                int b = batch(), c;
5291 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5292 +                    do {} while (!casPending(c = pending, c+1));
5293 +                    new SearchKeysTask<K,V,U>(this, b >>>= 1,
5294 +                                              searchFunction, result).fork();
5295 +                }
5296 +                U u;
5297 +                while (result.get() == null && advance() != null) {
5298 +                    if ((u = searchFunction.apply((K)nextKey)) != null) {
5299 +                        if (result.compareAndSet(null, u))
5300 +                            tryCompleteComputation(null);
5301 +                        break;
5302 +                    }
5303 +                }
5304 +                tryComplete();
5305 +            } catch (Throwable ex) {
5306 +                return tryCompleteComputation(ex);
5307 +            }
5308 +            return false;
5309 +        }
5310 +        public final U getRawResult() { return result.get(); }
5311 +    }
5312 +
5313 +    @SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5314 +        extends BulkTask<K,V,U> {
5315 +        final Fun<? super V, ? extends U> searchFunction;
5316 +        final AtomicReference<U> result;
5317 +        SearchValuesTask
5318 +            (ConcurrentHashMapV8<K,V> m,
5319 +             Fun<? super V, ? extends U> searchFunction,
5320 +             AtomicReference<U> result) {
5321 +            super(m);
5322 +            this.searchFunction = searchFunction; this.result = result;
5323 +        }
5324 +        SearchValuesTask
5325 +            (BulkTask<K,V,?> p, int b,
5326 +             Fun<? super V, ? extends U> searchFunction,
5327 +             AtomicReference<U> result) {
5328 +            super(p, b);
5329 +            this.searchFunction = searchFunction; this.result = result;
5330 +        }
5331 +        @SuppressWarnings("unchecked") public final boolean exec() {
5332 +            AtomicReference<U> result = this.result;
5333 +            final Fun<? super V, ? extends U> searchFunction =
5334 +                this.searchFunction;
5335 +            if (searchFunction == null || result == null)
5336 +                return abortOnNullFunction();
5337 +            try {
5338 +                int b = batch(), c;
5339 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5340 +                    do {} while (!casPending(c = pending, c+1));
5341 +                    new SearchValuesTask<K,V,U>(this, b >>>= 1,
5342 +                                                searchFunction, result).fork();
5343 +                }
5344 +                Object v; U u;
5345 +                while (result.get() == null && (v = advance()) != null) {
5346 +                    if ((u = searchFunction.apply((V)v)) != null) {
5347 +                        if (result.compareAndSet(null, u))
5348 +                            tryCompleteComputation(null);
5349 +                        break;
5350 +                    }
5351 +                }
5352 +                tryComplete();
5353 +            } catch (Throwable ex) {
5354 +                return tryCompleteComputation(ex);
5355 +            }
5356 +            return false;
5357 +        }
5358 +        public final U getRawResult() { return result.get(); }
5359 +    }
5360 +
5361 +    @SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5362 +        extends BulkTask<K,V,U> {
5363 +        final Fun<Entry<K,V>, ? extends U> searchFunction;
5364 +        final AtomicReference<U> result;
5365 +        SearchEntriesTask
5366 +            (ConcurrentHashMapV8<K,V> m,
5367 +             Fun<Entry<K,V>, ? extends U> searchFunction,
5368 +             AtomicReference<U> result) {
5369 +            super(m);
5370 +            this.searchFunction = searchFunction; this.result = result;
5371 +        }
5372 +        SearchEntriesTask
5373 +            (BulkTask<K,V,?> p, int b,
5374 +             Fun<Entry<K,V>, ? extends U> searchFunction,
5375 +             AtomicReference<U> result) {
5376 +            super(p, b);
5377 +            this.searchFunction = searchFunction; this.result = result;
5378 +        }
5379 +        @SuppressWarnings("unchecked") public final boolean exec() {
5380 +            AtomicReference<U> result = this.result;
5381 +            final Fun<Entry<K,V>, ? extends U> searchFunction =
5382 +                this.searchFunction;
5383 +            if (searchFunction == null || result == null)
5384 +                return abortOnNullFunction();
5385 +            try {
5386 +                int b = batch(), c;
5387 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5388 +                    do {} while (!casPending(c = pending, c+1));
5389 +                    new SearchEntriesTask<K,V,U>(this, b >>>= 1,
5390 +                                                 searchFunction, result).fork();
5391 +                }
5392 +                Object v; U u;
5393 +                while (result.get() == null && (v = advance()) != null) {
5394 +                    if ((u = searchFunction.apply(entryFor((K)nextKey, (V)v))) != null) {
5395 +                        if (result.compareAndSet(null, u))
5396 +                            tryCompleteComputation(null);
5397 +                        break;
5398 +                    }
5399 +                }
5400 +                tryComplete();
5401 +            } catch (Throwable ex) {
5402 +                return tryCompleteComputation(ex);
5403 +            }
5404 +            return false;
5405 +        }
5406 +        public final U getRawResult() { return result.get(); }
5407 +    }
5408 +
5409 +    @SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5410 +        extends BulkTask<K,V,U> {
5411 +        final BiFun<? super K, ? super V, ? extends U> searchFunction;
5412 +        final AtomicReference<U> result;
5413 +        SearchMappingsTask
5414 +            (ConcurrentHashMapV8<K,V> m,
5415 +             BiFun<? super K, ? super V, ? extends U> searchFunction,
5416 +             AtomicReference<U> result) {
5417 +            super(m);
5418 +            this.searchFunction = searchFunction; this.result = result;
5419 +        }
5420 +        SearchMappingsTask
5421 +            (BulkTask<K,V,?> p, int b,
5422 +             BiFun<? super K, ? super V, ? extends U> searchFunction,
5423 +             AtomicReference<U> result) {
5424 +            super(p, b);
5425 +            this.searchFunction = searchFunction; this.result = result;
5426 +        }
5427 +        @SuppressWarnings("unchecked") public final boolean exec() {
5428 +            AtomicReference<U> result = this.result;
5429 +            final BiFun<? super K, ? super V, ? extends U> searchFunction =
5430 +                this.searchFunction;
5431 +            if (searchFunction == null || result == null)
5432 +                return abortOnNullFunction();
5433 +            try {
5434 +                int b = batch(), c;
5435 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5436 +                    do {} while (!casPending(c = pending, c+1));
5437 +                    new SearchMappingsTask<K,V,U>(this, b >>>= 1,
5438 +                                                  searchFunction, result).fork();
5439 +                }
5440 +                Object v; U u;
5441 +                while (result.get() == null && (v = advance()) != null) {
5442 +                    if ((u = searchFunction.apply((K)nextKey, (V)v)) != null) {
5443 +                        if (result.compareAndSet(null, u))
5444 +                            tryCompleteComputation(null);
5445 +                        break;
5446 +                    }
5447 +                }
5448 +                tryComplete();
5449 +            } catch (Throwable ex) {
5450 +                return tryCompleteComputation(ex);
5451 +            }
5452 +            return false;
5453 +        }
5454 +        public final U getRawResult() { return result.get(); }
5455 +    }
5456 +
5457 +    @SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5458 +        extends BulkTask<K,V,K> {
5459 +        final BiFun<? super K, ? super K, ? extends K> reducer;
5460 +        K result;
5461 +        ReduceKeysTask<K,V> rights, nextRight;
5462 +        ReduceKeysTask
5463 +            (ConcurrentHashMapV8<K,V> m,
5464 +             BiFun<? super K, ? super K, ? extends K> reducer) {
5465 +            super(m);
5466 +            this.reducer = reducer;
5467 +        }
5468 +        ReduceKeysTask
5469 +            (BulkTask<K,V,?> p, int b,
5470 +             ReduceKeysTask<K,V> nextRight,
5471 +             BiFun<? super K, ? super K, ? extends K> reducer) {
5472 +            super(p, b); this.nextRight = nextRight;
5473 +            this.reducer = reducer;
5474 +        }
5475 +
5476 +        @SuppressWarnings("unchecked") public final boolean exec() {
5477 +            final BiFun<? super K, ? super K, ? extends K> reducer =
5478 +                this.reducer;
5479 +            if (reducer == null)
5480 +                return abortOnNullFunction();
5481 +            try {
5482 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5483 +                    do {} while (!casPending(c = pending, c+1));
5484 +                    (rights = new ReduceKeysTask<K,V>
5485 +                     (this, b >>>= 1, rights, reducer)).fork();
5486 +                }
5487 +                K r = null;
5488 +                while (advance() != null) {
5489 +                    K u = (K)nextKey;
5490 +                    r = (r == null) ? u : reducer.apply(r, u);
5491 +                }
5492 +                result = r;
5493 +                for (ReduceKeysTask<K,V> t = this, s;;) {
5494 +                    int c; BulkTask<K,V,?> par; K tr, sr;
5495 +                    if ((c = t.pending) == 0) {
5496 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5497 +                            if ((sr = s.result) != null)
5498 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5499 +                        }
5500 +                        if ((par = t.parent) == null ||
5501 +                            !(par instanceof ReduceKeysTask)) {
5502 +                            t.quietlyComplete();
5503 +                            break;
5504 +                        }
5505 +                        t = (ReduceKeysTask<K,V>)par;
5506 +                    }
5507 +                    else if (t.casPending(c, c - 1))
5508 +                        break;
5509 +                }
5510 +            } catch (Throwable ex) {
5511 +                return tryCompleteComputation(ex);
5512 +            }
5513 +            return false;
5514 +        }
5515 +        public final K getRawResult() { return result; }
5516 +    }
5517 +
5518 +    @SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5519 +        extends BulkTask<K,V,V> {
5520 +        final BiFun<? super V, ? super V, ? extends V> reducer;
5521 +        V result;
5522 +        ReduceValuesTask<K,V> rights, nextRight;
5523 +        ReduceValuesTask
5524 +            (ConcurrentHashMapV8<K,V> m,
5525 +             BiFun<? super V, ? super V, ? extends V> reducer) {
5526 +            super(m);
5527 +            this.reducer = reducer;
5528 +        }
5529 +        ReduceValuesTask
5530 +            (BulkTask<K,V,?> p, int b,
5531 +             ReduceValuesTask<K,V> nextRight,
5532 +             BiFun<? super V, ? super V, ? extends V> reducer) {
5533 +            super(p, b); this.nextRight = nextRight;
5534 +            this.reducer = reducer;
5535 +        }
5536 +
5537 +        @SuppressWarnings("unchecked") public final boolean exec() {
5538 +            final BiFun<? super V, ? super V, ? extends V> reducer =
5539 +                this.reducer;
5540 +            if (reducer == null)
5541 +                return abortOnNullFunction();
5542 +            try {
5543 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5544 +                    do {} while (!casPending(c = pending, c+1));
5545 +                    (rights = new ReduceValuesTask<K,V>
5546 +                     (this, b >>>= 1, rights, reducer)).fork();
5547 +                }
5548 +                V r = null;
5549 +                Object v;
5550 +                while ((v = advance()) != null) {
5551 +                    V u = (V)v;
5552 +                    r = (r == null) ? u : reducer.apply(r, u);
5553 +                }
5554 +                result = r;
5555 +                for (ReduceValuesTask<K,V> t = this, s;;) {
5556 +                    int c; BulkTask<K,V,?> par; V tr, sr;
5557 +                    if ((c = t.pending) == 0) {
5558 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5559 +                            if ((sr = s.result) != null)
5560 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5561 +                        }
5562 +                        if ((par = t.parent) == null ||
5563 +                            !(par instanceof ReduceValuesTask)) {
5564 +                            t.quietlyComplete();
5565 +                            break;
5566 +                        }
5567 +                        t = (ReduceValuesTask<K,V>)par;
5568 +                    }
5569 +                    else if (t.casPending(c, c - 1))
5570 +                        break;
5571 +                }
5572 +            } catch (Throwable ex) {
5573 +                return tryCompleteComputation(ex);
5574 +            }
5575 +            return false;
5576 +        }
5577 +        public final V getRawResult() { return result; }
5578 +    }
5579 +
5580 +    @SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
5581 +        extends BulkTask<K,V,Map.Entry<K,V>> {
5582 +        final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5583 +        Map.Entry<K,V> result;
5584 +        ReduceEntriesTask<K,V> rights, nextRight;
5585 +        ReduceEntriesTask
5586 +            (ConcurrentHashMapV8<K,V> m,
5587 +             BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5588 +            super(m);
5589 +            this.reducer = reducer;
5590 +        }
5591 +        ReduceEntriesTask
5592 +            (BulkTask<K,V,?> p, int b,
5593 +             ReduceEntriesTask<K,V> nextRight,
5594 +             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5595 +            super(p, b); this.nextRight = nextRight;
5596 +            this.reducer = reducer;
5597 +        }
5598 +
5599 +        @SuppressWarnings("unchecked") public final boolean exec() {
5600 +            final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer =
5601 +                this.reducer;
5602 +            if (reducer == null)
5603 +                return abortOnNullFunction();
5604 +            try {
5605 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5606 +                    do {} while (!casPending(c = pending, c+1));
5607 +                    (rights = new ReduceEntriesTask<K,V>
5608 +                     (this, b >>>= 1, rights, reducer)).fork();
5609 +                }
5610 +                Map.Entry<K,V> r = null;
5611 +                Object v;
5612 +                while ((v = advance()) != null) {
5613 +                    Map.Entry<K,V> u = entryFor((K)nextKey, (V)v);
5614 +                    r = (r == null) ? u : reducer.apply(r, u);
5615 +                }
5616 +                result = r;
5617 +                for (ReduceEntriesTask<K,V> t = this, s;;) {
5618 +                    int c; BulkTask<K,V,?> par; Map.Entry<K,V> tr, sr;
5619 +                    if ((c = t.pending) == 0) {
5620 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5621 +                            if ((sr = s.result) != null)
5622 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5623 +                        }
5624 +                        if ((par = t.parent) == null ||
5625 +                            !(par instanceof ReduceEntriesTask)) {
5626 +                            t.quietlyComplete();
5627 +                            break;
5628 +                        }
5629 +                        t = (ReduceEntriesTask<K,V>)par;
5630 +                    }
5631 +                    else if (t.casPending(c, c - 1))
5632 +                        break;
5633 +                }
5634 +            } catch (Throwable ex) {
5635 +                return tryCompleteComputation(ex);
5636 +            }
5637 +            return false;
5638 +        }
5639 +        public final Map.Entry<K,V> getRawResult() { return result; }
5640 +    }
5641 +
5642 +    @SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
5643 +        extends BulkTask<K,V,U> {
5644 +        final Fun<? super K, ? extends U> transformer;
5645 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5646 +        U result;
5647 +        MapReduceKeysTask<K,V,U> rights, nextRight;
5648 +        MapReduceKeysTask
5649 +            (ConcurrentHashMapV8<K,V> m,
5650 +             Fun<? super K, ? extends U> transformer,
5651 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5652 +            super(m);
5653 +            this.transformer = transformer;
5654 +            this.reducer = reducer;
5655 +        }
5656 +        MapReduceKeysTask
5657 +            (BulkTask<K,V,?> p, int b,
5658 +             MapReduceKeysTask<K,V,U> nextRight,
5659 +             Fun<? super K, ? extends U> transformer,
5660 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5661 +            super(p, b); this.nextRight = nextRight;
5662 +            this.transformer = transformer;
5663 +            this.reducer = reducer;
5664 +        }
5665 +        @SuppressWarnings("unchecked") public final boolean exec() {
5666 +            final Fun<? super K, ? extends U> transformer =
5667 +                this.transformer;
5668 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5669 +                this.reducer;
5670 +            if (transformer == null || reducer == null)
5671 +                return abortOnNullFunction();
5672 +            try {
5673 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5674 +                    do {} while (!casPending(c = pending, c+1));
5675 +                    (rights = new MapReduceKeysTask<K,V,U>
5676 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5677 +                }
5678 +                U r = null, u;
5679 +                while (advance() != null) {
5680 +                    if ((u = transformer.apply((K)nextKey)) != null)
5681 +                        r = (r == null) ? u : reducer.apply(r, u);
5682 +                }
5683 +                result = r;
5684 +                for (MapReduceKeysTask<K,V,U> t = this, s;;) {
5685 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5686 +                    if ((c = t.pending) == 0) {
5687 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5688 +                            if ((sr = s.result) != null)
5689 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5690 +                        }
5691 +                        if ((par = t.parent) == null ||
5692 +                            !(par instanceof MapReduceKeysTask)) {
5693 +                            t.quietlyComplete();
5694 +                            break;
5695 +                        }
5696 +                        t = (MapReduceKeysTask<K,V,U>)par;
5697 +                    }
5698 +                    else if (t.casPending(c, c - 1))
5699 +                        break;
5700 +                }
5701 +            } catch (Throwable ex) {
5702 +                return tryCompleteComputation(ex);
5703 +            }
5704 +            return false;
5705 +        }
5706 +        public final U getRawResult() { return result; }
5707 +    }
5708 +
5709 +    @SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
5710 +        extends BulkTask<K,V,U> {
5711 +        final Fun<? super V, ? extends U> transformer;
5712 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5713 +        U result;
5714 +        MapReduceValuesTask<K,V,U> rights, nextRight;
5715 +        MapReduceValuesTask
5716 +            (ConcurrentHashMapV8<K,V> m,
5717 +             Fun<? super V, ? extends U> transformer,
5718 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5719 +            super(m);
5720 +            this.transformer = transformer;
5721 +            this.reducer = reducer;
5722 +        }
5723 +        MapReduceValuesTask
5724 +            (BulkTask<K,V,?> p, int b,
5725 +             MapReduceValuesTask<K,V,U> nextRight,
5726 +             Fun<? super V, ? extends U> transformer,
5727 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5728 +            super(p, b); this.nextRight = nextRight;
5729 +            this.transformer = transformer;
5730 +            this.reducer = reducer;
5731 +        }
5732 +        @SuppressWarnings("unchecked") public final boolean exec() {
5733 +            final Fun<? super V, ? extends U> transformer =
5734 +                this.transformer;
5735 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5736 +                this.reducer;
5737 +            if (transformer == null || reducer == null)
5738 +                return abortOnNullFunction();
5739 +            try {
5740 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5741 +                    do {} while (!casPending(c = pending, c+1));
5742 +                    (rights = new MapReduceValuesTask<K,V,U>
5743 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5744 +                }
5745 +                U r = null, u;
5746 +                Object v;
5747 +                while ((v = advance()) != null) {
5748 +                    if ((u = transformer.apply((V)v)) != null)
5749 +                        r = (r == null) ? u : reducer.apply(r, u);
5750 +                }
5751 +                result = r;
5752 +                for (MapReduceValuesTask<K,V,U> t = this, s;;) {
5753 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5754 +                    if ((c = t.pending) == 0) {
5755 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5756 +                            if ((sr = s.result) != null)
5757 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5758 +                        }
5759 +                        if ((par = t.parent) == null ||
5760 +                            !(par instanceof MapReduceValuesTask)) {
5761 +                            t.quietlyComplete();
5762 +                            break;
5763 +                        }
5764 +                        t = (MapReduceValuesTask<K,V,U>)par;
5765 +                    }
5766 +                    else if (t.casPending(c, c - 1))
5767 +                        break;
5768 +                }
5769 +            } catch (Throwable ex) {
5770 +                return tryCompleteComputation(ex);
5771 +            }
5772 +            return false;
5773 +        }
5774 +        public final U getRawResult() { return result; }
5775 +    }
5776 +
5777 +    @SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
5778 +        extends BulkTask<K,V,U> {
5779 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5780 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5781 +        U result;
5782 +        MapReduceEntriesTask<K,V,U> rights, nextRight;
5783 +        MapReduceEntriesTask
5784 +            (ConcurrentHashMapV8<K,V> m,
5785 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5786 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5787 +            super(m);
5788 +            this.transformer = transformer;
5789 +            this.reducer = reducer;
5790 +        }
5791 +        MapReduceEntriesTask
5792 +            (BulkTask<K,V,?> p, int b,
5793 +             MapReduceEntriesTask<K,V,U> nextRight,
5794 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5795 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5796 +            super(p, b); this.nextRight = nextRight;
5797 +            this.transformer = transformer;
5798 +            this.reducer = reducer;
5799 +        }
5800 +        @SuppressWarnings("unchecked") public final boolean exec() {
5801 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5802 +                this.transformer;
5803 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5804 +                this.reducer;
5805 +            if (transformer == null || reducer == null)
5806 +                return abortOnNullFunction();
5807 +            try {
5808 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5809 +                    do {} while (!casPending(c = pending, c+1));
5810 +                    (rights = new MapReduceEntriesTask<K,V,U>
5811 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5812 +                }
5813 +                U r = null, u;
5814 +                Object v;
5815 +                while ((v = advance()) != null) {
5816 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5817 +                        r = (r == null) ? u : reducer.apply(r, u);
5818 +                }
5819 +                result = r;
5820 +                for (MapReduceEntriesTask<K,V,U> t = this, s;;) {
5821 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5822 +                    if ((c = t.pending) == 0) {
5823 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5824 +                            if ((sr = s.result) != null)
5825 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5826 +                        }
5827 +                        if ((par = t.parent) == null ||
5828 +                            !(par instanceof MapReduceEntriesTask)) {
5829 +                            t.quietlyComplete();
5830 +                            break;
5831 +                        }
5832 +                        t = (MapReduceEntriesTask<K,V,U>)par;
5833 +                    }
5834 +                    else if (t.casPending(c, c - 1))
5835 +                        break;
5836 +                }
5837 +            } catch (Throwable ex) {
5838 +                return tryCompleteComputation(ex);
5839 +            }
5840 +            return false;
5841 +        }
5842 +        public final U getRawResult() { return result; }
5843 +    }
5844 +
5845 +    @SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
5846 +        extends BulkTask<K,V,U> {
5847 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5848 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5849 +        U result;
5850 +        MapReduceMappingsTask<K,V,U> rights, nextRight;
5851 +        MapReduceMappingsTask
5852 +            (ConcurrentHashMapV8<K,V> m,
5853 +             BiFun<? super K, ? super V, ? extends U> transformer,
5854 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5855 +            super(m);
5856 +            this.transformer = transformer;
5857 +            this.reducer = reducer;
5858 +        }
5859 +        MapReduceMappingsTask
5860 +            (BulkTask<K,V,?> p, int b,
5861 +             MapReduceMappingsTask<K,V,U> nextRight,
5862 +             BiFun<? super K, ? super V, ? extends U> transformer,
5863 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5864 +            super(p, b); this.nextRight = nextRight;
5865 +            this.transformer = transformer;
5866 +            this.reducer = reducer;
5867 +        }
5868 +        @SuppressWarnings("unchecked") public final boolean exec() {
5869 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5870 +                this.transformer;
5871 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5872 +                this.reducer;
5873 +            if (transformer == null || reducer == null)
5874 +                return abortOnNullFunction();
5875 +            try {
5876 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5877 +                    do {} while (!casPending(c = pending, c+1));
5878 +                    (rights = new MapReduceMappingsTask<K,V,U>
5879 +                     (this, b >>>= 1, rights, transformer, reducer)).fork();
5880 +                }
5881 +                U r = null, u;
5882 +                Object v;
5883 +                while ((v = advance()) != null) {
5884 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5885 +                        r = (r == null) ? u : reducer.apply(r, u);
5886 +                }
5887 +                result = r;
5888 +                for (MapReduceMappingsTask<K,V,U> t = this, s;;) {
5889 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5890 +                    if ((c = t.pending) == 0) {
5891 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5892 +                            if ((sr = s.result) != null)
5893 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5894 +                        }
5895 +                        if ((par = t.parent) == null ||
5896 +                            !(par instanceof MapReduceMappingsTask)) {
5897 +                            t.quietlyComplete();
5898 +                            break;
5899 +                        }
5900 +                        t = (MapReduceMappingsTask<K,V,U>)par;
5901 +                    }
5902 +                    else if (t.casPending(c, c - 1))
5903 +                        break;
5904 +                }
5905 +            } catch (Throwable ex) {
5906 +                return tryCompleteComputation(ex);
5907 +            }
5908 +            return false;
5909 +        }
5910 +        public final U getRawResult() { return result; }
5911 +    }
5912 +
5913 +    @SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
5914 +        extends BulkTask<K,V,Double> {
5915 +        final ObjectToDouble<? super K> transformer;
5916 +        final DoubleByDoubleToDouble reducer;
5917 +        final double basis;
5918 +        double result;
5919 +        MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5920 +        MapReduceKeysToDoubleTask
5921 +            (ConcurrentHashMapV8<K,V> m,
5922 +             ObjectToDouble<? super K> transformer,
5923 +             double basis,
5924 +             DoubleByDoubleToDouble reducer) {
5925 +            super(m);
5926 +            this.transformer = transformer;
5927 +            this.basis = basis; this.reducer = reducer;
5928 +        }
5929 +        MapReduceKeysToDoubleTask
5930 +            (BulkTask<K,V,?> p, int b,
5931 +             MapReduceKeysToDoubleTask<K,V> nextRight,
5932 +             ObjectToDouble<? super K> transformer,
5933 +             double basis,
5934 +             DoubleByDoubleToDouble reducer) {
5935 +            super(p, b); this.nextRight = nextRight;
5936 +            this.transformer = transformer;
5937 +            this.basis = basis; this.reducer = reducer;
5938 +        }
5939 +        @SuppressWarnings("unchecked") public final boolean exec() {
5940 +            final ObjectToDouble<? super K> transformer =
5941 +                this.transformer;
5942 +            final DoubleByDoubleToDouble reducer = this.reducer;
5943 +            if (transformer == null || reducer == null)
5944 +                return abortOnNullFunction();
5945 +            try {
5946 +                final double id = this.basis;
5947 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5948 +                    do {} while (!casPending(c = pending, c+1));
5949 +                    (rights = new MapReduceKeysToDoubleTask<K,V>
5950 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
5951 +                }
5952 +                double r = id;
5953 +                while (advance() != null)
5954 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
5955 +                result = r;
5956 +                for (MapReduceKeysToDoubleTask<K,V> t = this, s;;) {
5957 +                    int c; BulkTask<K,V,?> par;
5958 +                    if ((c = t.pending) == 0) {
5959 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5960 +                            t.result = reducer.apply(t.result, s.result);
5961 +                        }
5962 +                        if ((par = t.parent) == null ||
5963 +                            !(par instanceof MapReduceKeysToDoubleTask)) {
5964 +                            t.quietlyComplete();
5965 +                            break;
5966 +                        }
5967 +                        t = (MapReduceKeysToDoubleTask<K,V>)par;
5968 +                    }
5969 +                    else if (t.casPending(c, c - 1))
5970 +                        break;
5971 +                }
5972 +            } catch (Throwable ex) {
5973 +                return tryCompleteComputation(ex);
5974 +            }
5975 +            return false;
5976 +        }
5977 +        public final Double getRawResult() { return result; }
5978 +    }
5979 +
5980 +    @SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
5981 +        extends BulkTask<K,V,Double> {
5982 +        final ObjectToDouble<? super V> transformer;
5983 +        final DoubleByDoubleToDouble reducer;
5984 +        final double basis;
5985 +        double result;
5986 +        MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5987 +        MapReduceValuesToDoubleTask
5988 +            (ConcurrentHashMapV8<K,V> m,
5989 +             ObjectToDouble<? super V> transformer,
5990 +             double basis,
5991 +             DoubleByDoubleToDouble reducer) {
5992 +            super(m);
5993 +            this.transformer = transformer;
5994 +            this.basis = basis; this.reducer = reducer;
5995 +        }
5996 +        MapReduceValuesToDoubleTask
5997 +            (BulkTask<K,V,?> p, int b,
5998 +             MapReduceValuesToDoubleTask<K,V> nextRight,
5999 +             ObjectToDouble<? super V> transformer,
6000 +             double basis,
6001 +             DoubleByDoubleToDouble reducer) {
6002 +            super(p, b); this.nextRight = nextRight;
6003 +            this.transformer = transformer;
6004 +            this.basis = basis; this.reducer = reducer;
6005 +        }
6006 +        @SuppressWarnings("unchecked") public final boolean exec() {
6007 +            final ObjectToDouble<? super V> transformer =
6008 +                this.transformer;
6009 +            final DoubleByDoubleToDouble reducer = this.reducer;
6010 +            if (transformer == null || reducer == null)
6011 +                return abortOnNullFunction();
6012 +            try {
6013 +                final double id = this.basis;
6014 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6015 +                    do {} while (!casPending(c = pending, c+1));
6016 +                    (rights = new MapReduceValuesToDoubleTask<K,V>
6017 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6018 +                }
6019 +                double r = id;
6020 +                Object v;
6021 +                while ((v = advance()) != null)
6022 +                    r = reducer.apply(r, transformer.apply((V)v));
6023 +                result = r;
6024 +                for (MapReduceValuesToDoubleTask<K,V> t = this, s;;) {
6025 +                    int c; BulkTask<K,V,?> par;
6026 +                    if ((c = t.pending) == 0) {
6027 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6028 +                            t.result = reducer.apply(t.result, s.result);
6029 +                        }
6030 +                        if ((par = t.parent) == null ||
6031 +                            !(par instanceof MapReduceValuesToDoubleTask)) {
6032 +                            t.quietlyComplete();
6033 +                            break;
6034 +                        }
6035 +                        t = (MapReduceValuesToDoubleTask<K,V>)par;
6036 +                    }
6037 +                    else if (t.casPending(c, c - 1))
6038 +                        break;
6039 +                }
6040 +            } catch (Throwable ex) {
6041 +                return tryCompleteComputation(ex);
6042 +            }
6043 +            return false;
6044 +        }
6045 +        public final Double getRawResult() { return result; }
6046 +    }
6047 +
6048 +    @SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6049 +        extends BulkTask<K,V,Double> {
6050 +        final ObjectToDouble<Map.Entry<K,V>> transformer;
6051 +        final DoubleByDoubleToDouble reducer;
6052 +        final double basis;
6053 +        double result;
6054 +        MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6055 +        MapReduceEntriesToDoubleTask
6056 +            (ConcurrentHashMapV8<K,V> m,
6057 +             ObjectToDouble<Map.Entry<K,V>> transformer,
6058 +             double basis,
6059 +             DoubleByDoubleToDouble reducer) {
6060 +            super(m);
6061 +            this.transformer = transformer;
6062 +            this.basis = basis; this.reducer = reducer;
6063 +        }
6064 +        MapReduceEntriesToDoubleTask
6065 +            (BulkTask<K,V,?> p, int b,
6066 +             MapReduceEntriesToDoubleTask<K,V> nextRight,
6067 +             ObjectToDouble<Map.Entry<K,V>> transformer,
6068 +             double basis,
6069 +             DoubleByDoubleToDouble reducer) {
6070 +            super(p, b); this.nextRight = nextRight;
6071 +            this.transformer = transformer;
6072 +            this.basis = basis; this.reducer = reducer;
6073 +        }
6074 +        @SuppressWarnings("unchecked") public final boolean exec() {
6075 +            final ObjectToDouble<Map.Entry<K,V>> transformer =
6076 +                this.transformer;
6077 +            final DoubleByDoubleToDouble reducer = this.reducer;
6078 +            if (transformer == null || reducer == null)
6079 +                return abortOnNullFunction();
6080 +            try {
6081 +                final double id = this.basis;
6082 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6083 +                    do {} while (!casPending(c = pending, c+1));
6084 +                    (rights = new MapReduceEntriesToDoubleTask<K,V>
6085 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6086 +                }
6087 +                double r = id;
6088 +                Object v;
6089 +                while ((v = advance()) != null)
6090 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6091 +                result = r;
6092 +                for (MapReduceEntriesToDoubleTask<K,V> t = this, s;;) {
6093 +                    int c; BulkTask<K,V,?> par;
6094 +                    if ((c = t.pending) == 0) {
6095 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6096 +                            t.result = reducer.apply(t.result, s.result);
6097 +                        }
6098 +                        if ((par = t.parent) == null ||
6099 +                            !(par instanceof MapReduceEntriesToDoubleTask)) {
6100 +                            t.quietlyComplete();
6101 +                            break;
6102 +                        }
6103 +                        t = (MapReduceEntriesToDoubleTask<K,V>)par;
6104 +                    }
6105 +                    else if (t.casPending(c, c - 1))
6106 +                        break;
6107 +                }
6108 +            } catch (Throwable ex) {
6109 +                return tryCompleteComputation(ex);
6110 +            }
6111 +            return false;
6112 +        }
6113 +        public final Double getRawResult() { return result; }
6114 +    }
6115 +
6116 +    @SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6117 +        extends BulkTask<K,V,Double> {
6118 +        final ObjectByObjectToDouble<? super K, ? super V> transformer;
6119 +        final DoubleByDoubleToDouble reducer;
6120 +        final double basis;
6121 +        double result;
6122 +        MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6123 +        MapReduceMappingsToDoubleTask
6124 +            (ConcurrentHashMapV8<K,V> m,
6125 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
6126 +             double basis,
6127 +             DoubleByDoubleToDouble reducer) {
6128 +            super(m);
6129 +            this.transformer = transformer;
6130 +            this.basis = basis; this.reducer = reducer;
6131 +        }
6132 +        MapReduceMappingsToDoubleTask
6133 +            (BulkTask<K,V,?> p, int b,
6134 +             MapReduceMappingsToDoubleTask<K,V> nextRight,
6135 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
6136 +             double basis,
6137 +             DoubleByDoubleToDouble reducer) {
6138 +            super(p, b); this.nextRight = nextRight;
6139 +            this.transformer = transformer;
6140 +            this.basis = basis; this.reducer = reducer;
6141 +        }
6142 +        @SuppressWarnings("unchecked") public final boolean exec() {
6143 +            final ObjectByObjectToDouble<? super K, ? super V> transformer =
6144 +                this.transformer;
6145 +            final DoubleByDoubleToDouble reducer = this.reducer;
6146 +            if (transformer == null || reducer == null)
6147 +                return abortOnNullFunction();
6148 +            try {
6149 +                final double id = this.basis;
6150 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6151 +                    do {} while (!casPending(c = pending, c+1));
6152 +                    (rights = new MapReduceMappingsToDoubleTask<K,V>
6153 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6154 +                }
6155 +                double r = id;
6156 +                Object v;
6157 +                while ((v = advance()) != null)
6158 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6159 +                result = r;
6160 +                for (MapReduceMappingsToDoubleTask<K,V> t = this, s;;) {
6161 +                    int c; BulkTask<K,V,?> par;
6162 +                    if ((c = t.pending) == 0) {
6163 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6164 +                            t.result = reducer.apply(t.result, s.result);
6165 +                        }
6166 +                        if ((par = t.parent) == null ||
6167 +                            !(par instanceof MapReduceMappingsToDoubleTask)) {
6168 +                            t.quietlyComplete();
6169 +                            break;
6170 +                        }
6171 +                        t = (MapReduceMappingsToDoubleTask<K,V>)par;
6172 +                    }
6173 +                    else if (t.casPending(c, c - 1))
6174 +                        break;
6175 +                }
6176 +            } catch (Throwable ex) {
6177 +                return tryCompleteComputation(ex);
6178 +            }
6179 +            return false;
6180 +        }
6181 +        public final Double getRawResult() { return result; }
6182 +    }
6183 +
6184 +    @SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6185 +        extends BulkTask<K,V,Long> {
6186 +        final ObjectToLong<? super K> transformer;
6187 +        final LongByLongToLong reducer;
6188 +        final long basis;
6189 +        long result;
6190 +        MapReduceKeysToLongTask<K,V> rights, nextRight;
6191 +        MapReduceKeysToLongTask
6192 +            (ConcurrentHashMapV8<K,V> m,
6193 +             ObjectToLong<? super K> transformer,
6194 +             long basis,
6195 +             LongByLongToLong reducer) {
6196 +            super(m);
6197 +            this.transformer = transformer;
6198 +            this.basis = basis; this.reducer = reducer;
6199 +        }
6200 +        MapReduceKeysToLongTask
6201 +            (BulkTask<K,V,?> p, int b,
6202 +             MapReduceKeysToLongTask<K,V> nextRight,
6203 +             ObjectToLong<? super K> transformer,
6204 +             long basis,
6205 +             LongByLongToLong reducer) {
6206 +            super(p, b); this.nextRight = nextRight;
6207 +            this.transformer = transformer;
6208 +            this.basis = basis; this.reducer = reducer;
6209 +        }
6210 +        @SuppressWarnings("unchecked") public final boolean exec() {
6211 +            final ObjectToLong<? super K> transformer =
6212 +                this.transformer;
6213 +            final LongByLongToLong reducer = this.reducer;
6214 +            if (transformer == null || reducer == null)
6215 +                return abortOnNullFunction();
6216 +            try {
6217 +                final long id = this.basis;
6218 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6219 +                    do {} while (!casPending(c = pending, c+1));
6220 +                    (rights = new MapReduceKeysToLongTask<K,V>
6221 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6222 +                }
6223 +                long r = id;
6224 +                while (advance() != null)
6225 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6226 +                result = r;
6227 +                for (MapReduceKeysToLongTask<K,V> t = this, s;;) {
6228 +                    int c; BulkTask<K,V,?> par;
6229 +                    if ((c = t.pending) == 0) {
6230 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6231 +                            t.result = reducer.apply(t.result, s.result);
6232 +                        }
6233 +                        if ((par = t.parent) == null ||
6234 +                            !(par instanceof MapReduceKeysToLongTask)) {
6235 +                            t.quietlyComplete();
6236 +                            break;
6237 +                        }
6238 +                        t = (MapReduceKeysToLongTask<K,V>)par;
6239 +                    }
6240 +                    else if (t.casPending(c, c - 1))
6241 +                        break;
6242 +                }
6243 +            } catch (Throwable ex) {
6244 +                return tryCompleteComputation(ex);
6245 +            }
6246 +            return false;
6247 +        }
6248 +        public final Long getRawResult() { return result; }
6249 +    }
6250 +
6251 +    @SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6252 +        extends BulkTask<K,V,Long> {
6253 +        final ObjectToLong<? super V> transformer;
6254 +        final LongByLongToLong reducer;
6255 +        final long basis;
6256 +        long result;
6257 +        MapReduceValuesToLongTask<K,V> rights, nextRight;
6258 +        MapReduceValuesToLongTask
6259 +            (ConcurrentHashMapV8<K,V> m,
6260 +             ObjectToLong<? super V> transformer,
6261 +             long basis,
6262 +             LongByLongToLong reducer) {
6263 +            super(m);
6264 +            this.transformer = transformer;
6265 +            this.basis = basis; this.reducer = reducer;
6266 +        }
6267 +        MapReduceValuesToLongTask
6268 +            (BulkTask<K,V,?> p, int b,
6269 +             MapReduceValuesToLongTask<K,V> nextRight,
6270 +             ObjectToLong<? super V> transformer,
6271 +             long basis,
6272 +             LongByLongToLong reducer) {
6273 +            super(p, b); this.nextRight = nextRight;
6274 +            this.transformer = transformer;
6275 +            this.basis = basis; this.reducer = reducer;
6276 +        }
6277 +        @SuppressWarnings("unchecked") public final boolean exec() {
6278 +            final ObjectToLong<? super V> transformer =
6279 +                this.transformer;
6280 +            final LongByLongToLong reducer = this.reducer;
6281 +            if (transformer == null || reducer == null)
6282 +                return abortOnNullFunction();
6283 +            try {
6284 +                final long id = this.basis;
6285 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6286 +                    do {} while (!casPending(c = pending, c+1));
6287 +                    (rights = new MapReduceValuesToLongTask<K,V>
6288 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6289 +                }
6290 +                long r = id;
6291 +                Object v;
6292 +                while ((v = advance()) != null)
6293 +                    r = reducer.apply(r, transformer.apply((V)v));
6294 +                result = r;
6295 +                for (MapReduceValuesToLongTask<K,V> t = this, s;;) {
6296 +                    int c; BulkTask<K,V,?> par;
6297 +                    if ((c = t.pending) == 0) {
6298 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6299 +                            t.result = reducer.apply(t.result, s.result);
6300 +                        }
6301 +                        if ((par = t.parent) == null ||
6302 +                            !(par instanceof MapReduceValuesToLongTask)) {
6303 +                            t.quietlyComplete();
6304 +                            break;
6305 +                        }
6306 +                        t = (MapReduceValuesToLongTask<K,V>)par;
6307 +                    }
6308 +                    else if (t.casPending(c, c - 1))
6309 +                        break;
6310 +                }
6311 +            } catch (Throwable ex) {
6312 +                return tryCompleteComputation(ex);
6313 +            }
6314 +            return false;
6315 +        }
6316 +        public final Long getRawResult() { return result; }
6317 +    }
6318 +
6319 +    @SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6320 +        extends BulkTask<K,V,Long> {
6321 +        final ObjectToLong<Map.Entry<K,V>> transformer;
6322 +        final LongByLongToLong reducer;
6323 +        final long basis;
6324 +        long result;
6325 +        MapReduceEntriesToLongTask<K,V> rights, nextRight;
6326 +        MapReduceEntriesToLongTask
6327 +            (ConcurrentHashMapV8<K,V> m,
6328 +             ObjectToLong<Map.Entry<K,V>> transformer,
6329 +             long basis,
6330 +             LongByLongToLong reducer) {
6331 +            super(m);
6332 +            this.transformer = transformer;
6333 +            this.basis = basis; this.reducer = reducer;
6334 +        }
6335 +        MapReduceEntriesToLongTask
6336 +            (BulkTask<K,V,?> p, int b,
6337 +             MapReduceEntriesToLongTask<K,V> nextRight,
6338 +             ObjectToLong<Map.Entry<K,V>> transformer,
6339 +             long basis,
6340 +             LongByLongToLong reducer) {
6341 +            super(p, b); this.nextRight = nextRight;
6342 +            this.transformer = transformer;
6343 +            this.basis = basis; this.reducer = reducer;
6344 +        }
6345 +        @SuppressWarnings("unchecked") public final boolean exec() {
6346 +            final ObjectToLong<Map.Entry<K,V>> transformer =
6347 +                this.transformer;
6348 +            final LongByLongToLong reducer = this.reducer;
6349 +            if (transformer == null || reducer == null)
6350 +                return abortOnNullFunction();
6351 +            try {
6352 +                final long id = this.basis;
6353 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6354 +                    do {} while (!casPending(c = pending, c+1));
6355 +                    (rights = new MapReduceEntriesToLongTask<K,V>
6356 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6357 +                }
6358 +                long r = id;
6359 +                Object v;
6360 +                while ((v = advance()) != null)
6361 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6362 +                result = r;
6363 +                for (MapReduceEntriesToLongTask<K,V> t = this, s;;) {
6364 +                    int c; BulkTask<K,V,?> par;
6365 +                    if ((c = t.pending) == 0) {
6366 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6367 +                            t.result = reducer.apply(t.result, s.result);
6368 +                        }
6369 +                        if ((par = t.parent) == null ||
6370 +                            !(par instanceof MapReduceEntriesToLongTask)) {
6371 +                            t.quietlyComplete();
6372 +                            break;
6373 +                        }
6374 +                        t = (MapReduceEntriesToLongTask<K,V>)par;
6375 +                    }
6376 +                    else if (t.casPending(c, c - 1))
6377 +                        break;
6378 +                }
6379 +            } catch (Throwable ex) {
6380 +                return tryCompleteComputation(ex);
6381 +            }
6382 +            return false;
6383 +        }
6384 +        public final Long getRawResult() { return result; }
6385 +    }
6386 +
6387 +    @SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6388 +        extends BulkTask<K,V,Long> {
6389 +        final ObjectByObjectToLong<? super K, ? super V> transformer;
6390 +        final LongByLongToLong reducer;
6391 +        final long basis;
6392 +        long result;
6393 +        MapReduceMappingsToLongTask<K,V> rights, nextRight;
6394 +        MapReduceMappingsToLongTask
6395 +            (ConcurrentHashMapV8<K,V> m,
6396 +             ObjectByObjectToLong<? super K, ? super V> transformer,
6397 +             long basis,
6398 +             LongByLongToLong reducer) {
6399 +            super(m);
6400 +            this.transformer = transformer;
6401 +            this.basis = basis; this.reducer = reducer;
6402 +        }
6403 +        MapReduceMappingsToLongTask
6404 +            (BulkTask<K,V,?> p, int b,
6405 +             MapReduceMappingsToLongTask<K,V> nextRight,
6406 +             ObjectByObjectToLong<? super K, ? super V> transformer,
6407 +             long basis,
6408 +             LongByLongToLong reducer) {
6409 +            super(p, b); this.nextRight = nextRight;
6410 +            this.transformer = transformer;
6411 +            this.basis = basis; this.reducer = reducer;
6412 +        }
6413 +        @SuppressWarnings("unchecked") public final boolean exec() {
6414 +            final ObjectByObjectToLong<? super K, ? super V> transformer =
6415 +                this.transformer;
6416 +            final LongByLongToLong reducer = this.reducer;
6417 +            if (transformer == null || reducer == null)
6418 +                return abortOnNullFunction();
6419 +            try {
6420 +                final long id = this.basis;
6421 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6422 +                    do {} while (!casPending(c = pending, c+1));
6423 +                    (rights = new MapReduceMappingsToLongTask<K,V>
6424 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6425 +                }
6426 +                long r = id;
6427 +                Object v;
6428 +                while ((v = advance()) != null)
6429 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6430 +                result = r;
6431 +                for (MapReduceMappingsToLongTask<K,V> t = this, s;;) {
6432 +                    int c; BulkTask<K,V,?> par;
6433 +                    if ((c = t.pending) == 0) {
6434 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6435 +                            t.result = reducer.apply(t.result, s.result);
6436 +                        }
6437 +                        if ((par = t.parent) == null ||
6438 +                            !(par instanceof MapReduceMappingsToLongTask)) {
6439 +                            t.quietlyComplete();
6440 +                            break;
6441 +                        }
6442 +                        t = (MapReduceMappingsToLongTask<K,V>)par;
6443 +                    }
6444 +                    else if (t.casPending(c, c - 1))
6445 +                        break;
6446 +                }
6447 +            } catch (Throwable ex) {
6448 +                return tryCompleteComputation(ex);
6449 +            }
6450 +            return false;
6451 +        }
6452 +        public final Long getRawResult() { return result; }
6453 +    }
6454 +
6455 +    @SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6456 +        extends BulkTask<K,V,Integer> {
6457 +        final ObjectToInt<? super K> transformer;
6458 +        final IntByIntToInt reducer;
6459 +        final int basis;
6460 +        int result;
6461 +        MapReduceKeysToIntTask<K,V> rights, nextRight;
6462 +        MapReduceKeysToIntTask
6463 +            (ConcurrentHashMapV8<K,V> m,
6464 +             ObjectToInt<? super K> transformer,
6465 +             int basis,
6466 +             IntByIntToInt reducer) {
6467 +            super(m);
6468 +            this.transformer = transformer;
6469 +            this.basis = basis; this.reducer = reducer;
6470 +        }
6471 +        MapReduceKeysToIntTask
6472 +            (BulkTask<K,V,?> p, int b,
6473 +             MapReduceKeysToIntTask<K,V> nextRight,
6474 +             ObjectToInt<? super K> transformer,
6475 +             int basis,
6476 +             IntByIntToInt reducer) {
6477 +            super(p, b); this.nextRight = nextRight;
6478 +            this.transformer = transformer;
6479 +            this.basis = basis; this.reducer = reducer;
6480 +        }
6481 +        @SuppressWarnings("unchecked") public final boolean exec() {
6482 +            final ObjectToInt<? super K> transformer =
6483 +                this.transformer;
6484 +            final IntByIntToInt reducer = this.reducer;
6485 +            if (transformer == null || reducer == null)
6486 +                return abortOnNullFunction();
6487 +            try {
6488 +                final int id = this.basis;
6489 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6490 +                    do {} while (!casPending(c = pending, c+1));
6491 +                    (rights = new MapReduceKeysToIntTask<K,V>
6492 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6493 +                }
6494 +                int r = id;
6495 +                while (advance() != null)
6496 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6497 +                result = r;
6498 +                for (MapReduceKeysToIntTask<K,V> t = this, s;;) {
6499 +                    int c; BulkTask<K,V,?> par;
6500 +                    if ((c = t.pending) == 0) {
6501 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6502 +                            t.result = reducer.apply(t.result, s.result);
6503 +                        }
6504 +                        if ((par = t.parent) == null ||
6505 +                            !(par instanceof MapReduceKeysToIntTask)) {
6506 +                            t.quietlyComplete();
6507 +                            break;
6508 +                        }
6509 +                        t = (MapReduceKeysToIntTask<K,V>)par;
6510 +                    }
6511 +                    else if (t.casPending(c, c - 1))
6512 +                        break;
6513 +                }
6514 +            } catch (Throwable ex) {
6515 +                return tryCompleteComputation(ex);
6516 +            }
6517 +            return false;
6518 +        }
6519 +        public final Integer getRawResult() { return result; }
6520 +    }
6521 +
6522 +    @SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6523 +        extends BulkTask<K,V,Integer> {
6524 +        final ObjectToInt<? super V> transformer;
6525 +        final IntByIntToInt reducer;
6526 +        final int basis;
6527 +        int result;
6528 +        MapReduceValuesToIntTask<K,V> rights, nextRight;
6529 +        MapReduceValuesToIntTask
6530 +            (ConcurrentHashMapV8<K,V> m,
6531 +             ObjectToInt<? super V> transformer,
6532 +             int basis,
6533 +             IntByIntToInt reducer) {
6534 +            super(m);
6535 +            this.transformer = transformer;
6536 +            this.basis = basis; this.reducer = reducer;
6537 +        }
6538 +        MapReduceValuesToIntTask
6539 +            (BulkTask<K,V,?> p, int b,
6540 +             MapReduceValuesToIntTask<K,V> nextRight,
6541 +             ObjectToInt<? super V> transformer,
6542 +             int basis,
6543 +             IntByIntToInt reducer) {
6544 +            super(p, b); this.nextRight = nextRight;
6545 +            this.transformer = transformer;
6546 +            this.basis = basis; this.reducer = reducer;
6547 +        }
6548 +        @SuppressWarnings("unchecked") public final boolean exec() {
6549 +            final ObjectToInt<? super V> transformer =
6550 +                this.transformer;
6551 +            final IntByIntToInt reducer = this.reducer;
6552 +            if (transformer == null || reducer == null)
6553 +                return abortOnNullFunction();
6554 +            try {
6555 +                final int id = this.basis;
6556 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6557 +                    do {} while (!casPending(c = pending, c+1));
6558 +                    (rights = new MapReduceValuesToIntTask<K,V>
6559 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6560 +                }
6561 +                int r = id;
6562 +                Object v;
6563 +                while ((v = advance()) != null)
6564 +                    r = reducer.apply(r, transformer.apply((V)v));
6565 +                result = r;
6566 +                for (MapReduceValuesToIntTask<K,V> t = this, s;;) {
6567 +                    int c; BulkTask<K,V,?> par;
6568 +                    if ((c = t.pending) == 0) {
6569 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6570 +                            t.result = reducer.apply(t.result, s.result);
6571 +                        }
6572 +                        if ((par = t.parent) == null ||
6573 +                            !(par instanceof MapReduceValuesToIntTask)) {
6574 +                            t.quietlyComplete();
6575 +                            break;
6576 +                        }
6577 +                        t = (MapReduceValuesToIntTask<K,V>)par;
6578 +                    }
6579 +                    else if (t.casPending(c, c - 1))
6580 +                        break;
6581 +                }
6582 +            } catch (Throwable ex) {
6583 +                return tryCompleteComputation(ex);
6584 +            }
6585 +            return false;
6586 +        }
6587 +        public final Integer getRawResult() { return result; }
6588 +    }
6589 +
6590 +    @SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6591 +        extends BulkTask<K,V,Integer> {
6592 +        final ObjectToInt<Map.Entry<K,V>> transformer;
6593 +        final IntByIntToInt reducer;
6594 +        final int basis;
6595 +        int result;
6596 +        MapReduceEntriesToIntTask<K,V> rights, nextRight;
6597 +        MapReduceEntriesToIntTask
6598 +            (ConcurrentHashMapV8<K,V> m,
6599 +             ObjectToInt<Map.Entry<K,V>> transformer,
6600 +             int basis,
6601 +             IntByIntToInt reducer) {
6602 +            super(m);
6603 +            this.transformer = transformer;
6604 +            this.basis = basis; this.reducer = reducer;
6605 +        }
6606 +        MapReduceEntriesToIntTask
6607 +            (BulkTask<K,V,?> p, int b,
6608 +             MapReduceEntriesToIntTask<K,V> nextRight,
6609 +             ObjectToInt<Map.Entry<K,V>> transformer,
6610 +             int basis,
6611 +             IntByIntToInt reducer) {
6612 +            super(p, b); this.nextRight = nextRight;
6613 +            this.transformer = transformer;
6614 +            this.basis = basis; this.reducer = reducer;
6615 +        }
6616 +        @SuppressWarnings("unchecked") public final boolean exec() {
6617 +            final ObjectToInt<Map.Entry<K,V>> transformer =
6618 +                this.transformer;
6619 +            final IntByIntToInt reducer = this.reducer;
6620 +            if (transformer == null || reducer == null)
6621 +                return abortOnNullFunction();
6622 +            try {
6623 +                final int id = this.basis;
6624 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6625 +                    do {} while (!casPending(c = pending, c+1));
6626 +                    (rights = new MapReduceEntriesToIntTask<K,V>
6627 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6628 +                }
6629 +                int r = id;
6630 +                Object v;
6631 +                while ((v = advance()) != null)
6632 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6633 +                result = r;
6634 +                for (MapReduceEntriesToIntTask<K,V> t = this, s;;) {
6635 +                    int c; BulkTask<K,V,?> par;
6636 +                    if ((c = t.pending) == 0) {
6637 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6638 +                            t.result = reducer.apply(t.result, s.result);
6639 +                        }
6640 +                        if ((par = t.parent) == null ||
6641 +                            !(par instanceof MapReduceEntriesToIntTask)) {
6642 +                            t.quietlyComplete();
6643 +                            break;
6644 +                        }
6645 +                        t = (MapReduceEntriesToIntTask<K,V>)par;
6646 +                    }
6647 +                    else if (t.casPending(c, c - 1))
6648 +                        break;
6649 +                }
6650 +            } catch (Throwable ex) {
6651 +                return tryCompleteComputation(ex);
6652 +            }
6653 +            return false;
6654 +        }
6655 +        public final Integer getRawResult() { return result; }
6656 +    }
6657 +
6658 +    @SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6659 +        extends BulkTask<K,V,Integer> {
6660 +        final ObjectByObjectToInt<? super K, ? super V> transformer;
6661 +        final IntByIntToInt reducer;
6662 +        final int basis;
6663 +        int result;
6664 +        MapReduceMappingsToIntTask<K,V> rights, nextRight;
6665 +        MapReduceMappingsToIntTask
6666 +            (ConcurrentHashMapV8<K,V> m,
6667 +             ObjectByObjectToInt<? super K, ? super V> transformer,
6668 +             int basis,
6669 +             IntByIntToInt reducer) {
6670 +            super(m);
6671 +            this.transformer = transformer;
6672 +            this.basis = basis; this.reducer = reducer;
6673 +        }
6674 +        MapReduceMappingsToIntTask
6675 +            (BulkTask<K,V,?> p, int b,
6676 +             MapReduceMappingsToIntTask<K,V> nextRight,
6677 +             ObjectByObjectToInt<? super K, ? super V> transformer,
6678 +             int basis,
6679 +             IntByIntToInt reducer) {
6680 +            super(p, b); this.nextRight = nextRight;
6681 +            this.transformer = transformer;
6682 +            this.basis = basis; this.reducer = reducer;
6683 +        }
6684 +        @SuppressWarnings("unchecked") public final boolean exec() {
6685 +            final ObjectByObjectToInt<? super K, ? super V> transformer =
6686 +                this.transformer;
6687 +            final IntByIntToInt reducer = this.reducer;
6688 +            if (transformer == null || reducer == null)
6689 +                return abortOnNullFunction();
6690 +            try {
6691 +                final int id = this.basis;
6692 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6693 +                    do {} while (!casPending(c = pending, c+1));
6694 +                    (rights = new MapReduceMappingsToIntTask<K,V>
6695 +                     (this, b >>>= 1, rights, transformer, id, reducer)).fork();
6696 +                }
6697 +                int r = id;
6698 +                Object v;
6699 +                while ((v = advance()) != null)
6700 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6701 +                result = r;
6702 +                for (MapReduceMappingsToIntTask<K,V> t = this, s;;) {
6703 +                    int c; BulkTask<K,V,?> par;
6704 +                    if ((c = t.pending) == 0) {
6705 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6706 +                            t.result = reducer.apply(t.result, s.result);
6707 +                        }
6708 +                        if ((par = t.parent) == null ||
6709 +                            !(par instanceof MapReduceMappingsToIntTask)) {
6710 +                            t.quietlyComplete();
6711 +                            break;
6712 +                        }
6713 +                        t = (MapReduceMappingsToIntTask<K,V>)par;
6714 +                    }
6715 +                    else if (t.casPending(c, c - 1))
6716 +                        break;
6717 +                }
6718 +            } catch (Throwable ex) {
6719 +                return tryCompleteComputation(ex);
6720 +            }
6721 +            return false;
6722 +        }
6723 +        public final Integer getRawResult() { return result; }
6724 +    }
6725 +
6726 +
6727      // Unsafe mechanics
6728      private static final sun.misc.Unsafe UNSAFE;
6729      private static final long counterOffset;
6730 <    private static final long resizingOffset;
6730 >    private static final long sizeCtlOffset;
6731      private static final long ABASE;
6732      private static final int ASHIFT;
6733  
# Line 1693 | Line 6738 | public class ConcurrentHashMapV8<K, V>
6738              Class<?> k = ConcurrentHashMapV8.class;
6739              counterOffset = UNSAFE.objectFieldOffset
6740                  (k.getDeclaredField("counter"));
6741 <            resizingOffset = UNSAFE.objectFieldOffset
6742 <                (k.getDeclaredField("resizing"));
6741 >            sizeCtlOffset = UNSAFE.objectFieldOffset
6742 >                (k.getDeclaredField("sizeCtl"));
6743              Class<?> sc = Node[].class;
6744              ABASE = UNSAFE.arrayBaseOffset(sc);
6745              ss = UNSAFE.arrayIndexScale(sc);
# Line 1733 | Line 6778 | public class ConcurrentHashMapV8<K, V>
6778              }
6779          }
6780      }
1736
6781   }

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