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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.15 by jsr166, Thu Sep 8 23:34:50 2011 UTC vs.
Revision 1.64 by jsr166, Tue Oct 2 05:07:19 2012 UTC

# Line 6 | Line 6
6  
7   package jsr166e;
8   import jsr166e.LongAdder;
9 + import jsr166e.ForkJoinPool;
10 + import jsr166e.ForkJoinTask;
11 +
12 + import java.util.Comparator;
13 + import java.util.Arrays;
14   import java.util.Map;
15   import java.util.Set;
16   import java.util.Collection;
# Line 19 | Line 24 | import java.util.Enumeration;
24   import java.util.ConcurrentModificationException;
25   import java.util.NoSuchElementException;
26   import java.util.concurrent.ConcurrentMap;
27 + import java.util.concurrent.ThreadLocalRandom;
28 + import java.util.concurrent.locks.LockSupport;
29 + import java.util.concurrent.locks.AbstractQueuedSynchronizer;
30 + import java.util.concurrent.atomic.AtomicReference;
31 +
32   import java.io.Serializable;
33  
34   /**
# Line 37 | Line 47 | import java.io.Serializable;
47   * block, so may overlap with update operations (including {@code put}
48   * and {@code remove}). Retrievals reflect the results of the most
49   * recently <em>completed</em> update operations holding upon their
50 < * onset.  For aggregate operations such as {@code putAll} and {@code
51 < * clear}, concurrent retrievals may reflect insertion or removal of
52 < * only some entries.  Similarly, Iterators and Enumerations return
53 < * elements reflecting the state of the hash table at some point at or
54 < * since the creation of the iterator/enumeration.  They do
55 < * <em>not</em> throw {@link ConcurrentModificationException}.
56 < * However, iterators are designed to be used by only one thread at a
57 < * time.  Bear in mind that the results of aggregate status methods
58 < * including {@code size}, {@code isEmpty}, and {@code containsValue}
59 < * are typically useful only when a map is not undergoing concurrent
60 < * updates in other threads.  Otherwise the results of these methods
61 < * reflect transient states that may be adequate for monitoring
62 < * purposes, but not for program control.
50 > * onset. (More formally, an update operation for a given key bears a
51 > * <em>happens-before</em> relation with any (non-null) retrieval for
52 > * that key reporting the updated value.)  For aggregate operations
53 > * such as {@code putAll} and {@code clear}, concurrent retrievals may
54 > * reflect insertion or removal of only some entries.  Similarly,
55 > * Iterators and Enumerations return elements reflecting the state of
56 > * the hash table at some point at or since the creation of the
57 > * iterator/enumeration.  They do <em>not</em> throw {@link
58 > * ConcurrentModificationException}.  However, iterators are designed
59 > * to be used by only one thread at a time.  Bear in mind that the
60 > * results of aggregate status methods including {@code size}, {@code
61 > * isEmpty}, and {@code containsValue} are typically useful only when
62 > * a map is not undergoing concurrent updates in other threads.
63 > * Otherwise the results of these methods reflect transient states
64 > * that may be adequate for monitoring or estimation purposes, but not
65 > * for program control.
66   *
67 < * <p> Resizing this or any other kind of hash table is a relatively
68 < * slow operation, so, when possible, it is a good idea to provide
69 < * estimates of expected table sizes in constructors. Also, for
70 < * compatibility with previous versions of this class, constructors
71 < * may optionally specify an expected {@code concurrencyLevel} as an
72 < * additional hint for internal sizing.
67 > * <p> The table is dynamically expanded when there are too many
68 > * collisions (i.e., keys that have distinct hash codes but fall into
69 > * the same slot modulo the table size), with the expected average
70 > * effect of maintaining roughly two bins per mapping (corresponding
71 > * to a 0.75 load factor threshold for resizing). There may be much
72 > * variance around this average as mappings are added and removed, but
73 > * overall, this maintains a commonly accepted time/space tradeoff for
74 > * hash tables.  However, resizing this or any other kind of hash
75 > * table may be a relatively slow operation. When possible, it is a
76 > * good idea to provide a size estimate as an optional {@code
77 > * initialCapacity} constructor argument. An additional optional
78 > * {@code loadFactor} constructor argument provides a further means of
79 > * customizing initial table capacity by specifying the table density
80 > * to be used in calculating the amount of space to allocate for the
81 > * given number of elements.  Also, for compatibility with previous
82 > * versions of this class, constructors may optionally specify an
83 > * expected {@code concurrencyLevel} as an additional hint for
84 > * internal sizing.  Note that using many keys with exactly the same
85 > * {@code hashCode()} is a sure way to slow down performance of any
86 > * hash table.
87   *
88   * <p>This class and its views and iterators implement all of the
89   * <em>optional</em> methods of the {@link Map} and {@link Iterator}
# Line 70 | Line 97 | import java.io.Serializable;
97   * Java Collections Framework</a>.
98   *
99   * <p><em>jsr166e note: This class is a candidate replacement for
100 < * java.util.concurrent.ConcurrentHashMap.<em>
100 > * java.util.concurrent.ConcurrentHashMap.  During transition, this
101 > * class declares and uses nested functional interfaces with different
102 > * names but the same forms as those expected for JDK8.<em>
103   *
104   * @since 1.5
105   * @author Doug Lea
# Line 78 | Line 107 | import java.io.Serializable;
107   * @param <V> the type of mapped values
108   */
109   public class ConcurrentHashMapV8<K, V>
110 <        implements ConcurrentMap<K, V>, Serializable {
110 >    implements ConcurrentMap<K, V>, Serializable {
111      private static final long serialVersionUID = 7249069246763182397L;
112  
113      /**
114 <     * A function computing a mapping from the given key to a value,
115 <     * or {@code null} if there is no mapping. This is a place-holder
116 <     * for an upcoming JDK8 interface.
117 <     */
118 <    public static interface MappingFunction<K, V> {
119 <        /**
120 <         * Returns a value for the given key, or null if there is no
121 <         * mapping. If this function throws an (unchecked) exception,
122 <         * the exception is rethrown to its caller, and no mapping is
123 <         * recorded.  Because this function is invoked within
124 <         * atomicity control, the computation should be short and
125 <         * simple. The most common usage is to construct a new object
126 <         * serving as an initial mapped value.
114 >     * A partitionable iterator. A Spliterator can be traversed
115 >     * directly, but can also be partitioned (before traversal) by
116 >     * creating another Spliterator that covers a non-overlapping
117 >     * portion of the elements, and so may be amenable to parallel
118 >     * execution.
119 >     *
120 >     * <p> This interface exports a subset of expected JDK8
121 >     * functionality.
122 >     *
123 >     * <p>Sample usage: Here is one (of the several) ways to compute
124 >     * the sum of the values held in a map using the ForkJoin
125 >     * framework. As illustrated here, Spliterators are well suited to
126 >     * designs in which a task repeatedly splits off half its work
127 >     * into forked subtasks until small enough to process directly,
128 >     * and then joins these subtasks. Variants of this style can also
129 >     * be used in completion-based designs.
130 >     *
131 >     * <pre>
132 >     * {@code ConcurrentHashMapV8<String, Long> m = ...
133 >     * // split as if have 8 * parallelism, for load balance
134 >     * int n = m.size();
135 >     * int p = aForkJoinPool.getParallelism() * 8;
136 >     * int split = (n < p)? n : p;
137 >     * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
138 >     * // ...
139 >     * static class SumValues extends RecursiveTask<Long> {
140 >     *   final Spliterator<Long> s;
141 >     *   final int split;             // split while > 1
142 >     *   final SumValues nextJoin;    // records forked subtasks to join
143 >     *   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
144 >     *     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
145 >     *   }
146 >     *   public Long compute() {
147 >     *     long sum = 0;
148 >     *     SumValues subtasks = null; // fork subtasks
149 >     *     for (int s = split >>> 1; s > 0; s >>>= 1)
150 >     *       (subtasks = new SumValues(s.split(), s, subtasks)).fork();
151 >     *     while (s.hasNext())        // directly process remaining elements
152 >     *       sum += s.next();
153 >     *     for (SumValues t = subtasks; t != null; t = t.nextJoin)
154 >     *       sum += t.join();         // collect subtask results
155 >     *     return sum;
156 >     *   }
157 >     * }
158 >     * }</pre>
159 >     */
160 >    public static interface Spliterator<T> extends Iterator<T> {
161 >        /**
162 >         * Returns a Spliterator covering approximately half of the
163 >         * elements, guaranteed not to overlap with those subsequently
164 >         * returned by this Spliterator.  After invoking this method,
165 >         * the current Spliterator will <em>not</em> produce any of
166 >         * the elements of the returned Spliterator, but the two
167 >         * Spliterators together will produce all of the elements that
168 >         * would have been produced by this Spliterator had this
169 >         * method not been called. The exact number of elements
170 >         * produced by the returned Spliterator is not guaranteed, and
171 >         * may be zero (i.e., with {@code hasNext()} reporting {@code
172 >         * false}) if this Spliterator cannot be further split.
173           *
174 <         * @param key the (non-null) key
175 <         * @return a value, or null if none
174 >         * @return a Spliterator covering approximately half of the
175 >         * elements
176 >         * @throws IllegalStateException if this Spliterator has
177 >         * already commenced traversing elements
178           */
179 <        V map(K key);
179 >        Spliterator<T> split();
180      }
181  
182      /*
# Line 108 | Line 185 | public class ConcurrentHashMapV8<K, V>
185       * The primary design goal of this hash table is to maintain
186       * concurrent readability (typically method get(), but also
187       * iterators and related methods) while minimizing update
188 <     * contention.
188 >     * contention. Secondary goals are to keep space consumption about
189 >     * the same or better than java.util.HashMap, and to support high
190 >     * initial insertion rates on an empty table by many threads.
191       *
192       * Each key-value mapping is held in a Node.  Because Node fields
193       * can contain special values, they are defined using plain Object
# Line 116 | 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
157 <     * 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 0.5 on average under the default loadFactor of
262 <     * 0.75. The expected number of locks covering different elements
263 <     * (i.e., bins with 2 or more nodes) is approximately 10% at
264 <     * steady state.  Lock contention probability for two threads
265 <     * accessing distinct elements is roughly 1 / (8 * #elements).
266 <     * Function "spread" performs hashCode randomization that improves
267 <     * the likelihood that these assumptions hold unless users define
268 <     * exactly the same value for too many hashCodes.
269 <     *
270 <     * The table is resized when occupancy exceeds a threshold.  Only
271 <     * a single thread performs the resize (using field "resizing", to
272 <     * arrange exclusion), but the table otherwise remains usable for
273 <     * reads and updates. Resizing proceeds by transferring bins, one
274 <     * by one, from the table to the next table.  Upon transfer, the
275 <     * old table bin contains only a special forwarding node (with
276 <     * negative hash field) that contains the next table as its
277 <     * key. On encountering a forwarding node, access and update
278 <     * operations restart, using the new table. To ensure concurrent
279 <     * readability of traversals, transfers must proceed from the last
280 <     * bin (table.length - 1) up towards the first.  Upon seeing a
281 <     * forwarding node, traversals (see class InternalIterator)
282 <     * arrange to move to the new table for the rest of the traversal
283 <     * without revisiting nodes.  This constrains bin transfers to a
284 <     * particular order, and so can block indefinitely waiting for the
285 <     * next lock, and other threads cannot help with the transfer.
286 <     * However, expected stalls are infrequent enough to not warrant
287 <     * the additional overhead of access and iteration schemes that
288 <     * could admit out-of-order or concurrent bin transfers.
289 <     *
290 <     * This traversal scheme also applies to partial traversals of
291 <     * ranges of bins (via an alternate InternalIterator constructor)
292 <     * to support partitioned aggregate operations (that are not
293 <     * otherwise implemented yet).  Also, read-only operations give up
294 <     * if ever forwarded to a null table, which provides support for
295 <     * shutdown-style clearing, which is also not currently
296 <     * implemented.
261 >     * parameter of about 0.5 on average, given the resizing threshold
262 >     * of 0.75, although with a large variance because of resizing
263 >     * granularity. Ignoring variance, the expected occurrences of
264 >     * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
265 >     * first values are:
266 >     *
267 >     * 0:    0.60653066
268 >     * 1:    0.30326533
269 >     * 2:    0.07581633
270 >     * 3:    0.01263606
271 >     * 4:    0.00157952
272 >     * 5:    0.00015795
273 >     * 6:    0.00001316
274 >     * 7:    0.00000094
275 >     * 8:    0.00000006
276 >     * more: less than 1 in ten million
277 >     *
278 >     * Lock contention probability for two threads accessing distinct
279 >     * elements is roughly 1 / (8 * #elements) under random hashes.
280 >     *
281 >     * Actual hash code distributions encountered in practice
282 >     * sometimes deviate significantly from uniform randomness.  This
283 >     * includes the case when N > (1<<30), so some keys MUST collide.
284 >     * Similarly for dumb or hostile usages in which multiple keys are
285 >     * designed to have identical hash codes. Also, although we guard
286 >     * against the worst effects of this (see method spread), sets of
287 >     * hashes may differ only in bits that do not impact their bin
288 >     * index for a given power-of-two mask.  So we use a secondary
289 >     * strategy that applies when the number of nodes in a bin exceeds
290 >     * a threshold, and at least one of the keys implements
291 >     * Comparable.  These TreeBins use a balanced tree to hold nodes
292 >     * (a specialized form of red-black trees), bounding search time
293 >     * to O(log N).  Each search step in a TreeBin is around twice as
294 >     * slow as in a regular list, but given that N cannot exceed
295 >     * (1<<64) (before running out of addresses) this bounds search
296 >     * steps, lock hold times, etc, to reasonable constants (roughly
297 >     * 100 nodes inspected per operation worst case) so long as keys
298 >     * are Comparable (which is very common -- String, Long, etc).
299 >     * TreeBin nodes (TreeNodes) also maintain the same "next"
300 >     * traversal pointers as regular nodes, so can be traversed in
301 >     * iterators in the same way.
302 >     *
303 >     * The table is resized when occupancy exceeds a percentage
304 >     * threshold (nominally, 0.75, but see below).  Only a single
305 >     * thread performs the resize (using field "sizeCtl", to arrange
306 >     * exclusion), but the table otherwise remains usable for reads
307 >     * and updates. Resizing proceeds by transferring bins, one by
308 >     * one, from the table to the next table.  Because we are using
309 >     * power-of-two expansion, the elements from each bin must either
310 >     * stay at same index, or move with a power of two offset. We
311 >     * eliminate unnecessary node creation by catching cases where old
312 >     * nodes can be reused because their next fields won't change.  On
313 >     * average, only about one-sixth of them need cloning when a table
314 >     * doubles. The nodes they replace will be garbage collectable as
315 >     * soon as they are no longer referenced by any reader thread that
316 >     * may be in the midst of concurrently traversing table.  Upon
317 >     * transfer, the old table bin contains only a special forwarding
318 >     * node (with hash field "MOVED") that contains the next table as
319 >     * its key. On encountering a forwarding node, access and update
320 >     * operations restart, using the new table.
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 (which may harmlessly fail to take effect in cases of
201 <     * races with other ongoing resizings).
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 the default load
360 <     * factor and uniform hash distributions, the probability of this
361 <     * occurring at threshold is around 13%, meaning that only about 1
362 <     * in 8 puts check threshold (and after resizing, many fewer do
363 <     * so). But this approximation has high variance for small table
364 <     * sizes, so we check on any collision for sizes <= 64.  Further,
365 <     * to increase the probability that a resize occurs soon enough,
366 <     * we offset the threshold (see THRESHOLD_OFFSET) by the expected
367 <     * number of puts between checks. This is currently set to 8, in
368 <     * accord with the default load factor. In practice, this default
217 <     * is rarely overridden, and in any case is close enough to other
218 <     * plausible values not to waste dynamic probability computation
219 <     * for the sake of more precision.
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 -------------- */
381  
382      /**
383 <     * The largest allowed table capacity.  Must be a power of 2, at
384 <     * most 1<<30 to stay within Java array size limits.
383 >     * The largest possible table capacity.  This value must be
384 >     * exactly 1<<30 to stay within Java array allocation and indexing
385 >     * bounds for power of two table sizes, and is further required
386 >     * because the top two bits of 32bit hash fields are used for
387 >     * control purposes.
388       */
389      private static final int MAXIMUM_CAPACITY = 1 << 30;
390  
# Line 240 | Line 395 | public class ConcurrentHashMapV8<K, V>
395      private static final int DEFAULT_CAPACITY = 16;
396  
397      /**
398 <     * The default load factor for this table, used when not otherwise
399 <     * specified in a constructor.
398 >     * The largest possible (non-power of two) array size.
399 >     * Needed by toArray and related methods.
400       */
401 <    private static final float DEFAULT_LOAD_FACTOR = 0.75f;
401 >    static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
402  
403      /**
404 <     * The default concurrency level for this table. Unused, but
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 DEFAULT_CONCURRENCY_LEVEL = 16;
408  
409      /**
410 <     * The count value to offset thresholds to compensate for checking
411 <     * for the need to resize only when inserting into bins with two
412 <     * or more elements. See above for explanation.
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 THRESHOLD_OFFSET = 8;
260 <
261 <    /* ---------------- 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,
267 <     * keys are never null, and null val fields indicate that a node
268 <     * is in the process of being deleted or created. For purposes of
269 <     * read-only, access, a key may be read before a val, but can only
270 <     * be used after checking val.  (For an update operation, when a
271 <     * 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 {
274 <        final int hash;
275 <        final Object key;
276 <        volatile Object val;
277 <        volatile Node next;
278 <
279 <        Node(int hash, Object key, Object val, Node next) {
280 <            this.hash = hash;
281 <            this.key = key;
282 <            this.val = val;
283 <            this.next = next;
284 <        }
285 <    }
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 SIGN_BIT = 0x80000000;
430 >    private static final int TREE_THRESHOLD = 8;
431 >
432 >    /*
433 >     * Encodings for special uses of Node hash fields. See above for
434 >     * explanation.
435 >     */
436 >    static final int MOVED     = 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 297 | 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;
459 <    /** The target load factor for the table */
460 <    private transient final float loadFactor;
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 330 | 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 342 | 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;
356 <        n |= n >>> 8;
357 <        n |= n >>> 16;
358 <        return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
359 <    }
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;
531 <                    if (tab == null)
532 <                        n = (c = targetCapacity) > 0 ? c : DEFAULT_CAPACITY;
533 <                    else if ((n = tab.length) < MAXIMUM_CAPACITY &&
534 <                             counter.sum() >= threshold)
535 <                        n <<= 1;
536 <                    else
537 <                        break;
538 <                    Node[] nextTab = new Node[n];
539 <                    threshold = (int)(n * loadFactor) - THRESHOLD_OFFSET;
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                  }
393            } finally {
394                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 <    /*
594 <     * Reclassifies nodes in each bin to new table.  Because we are
595 <     * using power-of-two expansion, the elements from each bin must
596 <     * either stay at same index, or move with a power of two
406 <     * offset. We eliminate unnecessary node creation by catching
407 <     * cases where old nodes can be reused because their next fields
408 <     * won't change.  Statistically, at the default loadFactor, only
409 <     * about one-sixth of them need cloning when a table doubles. The
410 <     * nodes they replace will be garbage collectable as soon as they
411 <     * are no longer referenced by any reader thread that may be in
412 <     * the midst of concurrently traversing table.
413 <     *
414 <     * Transfers are done from the bottom up to preserve iterator
415 <     * traversability. On each step, the old bin is locked,
416 <     * moved/copied, and then replaced with a forwarding node.
593 >    /* ---------------- TreeBins -------------- */
594 >
595 >    /**
596 >     * Nodes for use in TreeBins
597       */
598 <    private static final void transfer(Node[] tab, Node[] nextTab, Node fwd) {
599 <        int n = tab.length;
600 <        Node ignore = nextTab[n + n - 1]; // force bounds check
601 <        for (int i = n - 1; i >= 0; --i) {
602 <            for (Node e;;) {
603 <                if ((e = tabAt(tab, i)) != null) {
604 <                    boolean validated = false;
605 <                    synchronized (e) {
606 <                        if (tabAt(tab, i) == e) {
607 <                            validated = true;
608 <                            Node lo = null, hi = null, lastRun = e;
609 <                            int runBit = e.hash & n;
610 <                            for (Node p = e.next; p != null; p = p.next) {
611 <                                int b = p.hash & n;
612 <                                if (b != runBit) {
613 <                                    runBit = b;
614 <                                    lastRun = p;
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 >     * TreeBins use a special form of comparison for search and
616 >     * related operations (which is the main reason we cannot use
617 >     * existing collections such as TreeMaps). TreeBins contain
618 >     * Comparable elements, but may contain others, as well as
619 >     * elements that are Comparable but not necessarily Comparable<T>
620 >     * for the same T, so we cannot invoke compareTo among them. To
621 >     * handle this, the tree is ordered primarily by hash value, then
622 >     * by getClass().getName() order, and then by Comparator order
623 >     * among elements of the same class.  On lookup at a node, if
624 >     * elements are not comparable or compare as 0, both left and
625 >     * right children may need to be searched in the case of tied hash
626 >     * values. (This corresponds to the full list search that would be
627 >     * necessary if all elements were non-Comparable and had tied
628 >     * hashes.)  The red-black balancing code is updated from
629 >     * pre-jdk-collections
630 >     * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
631 >     * based in turn on Cormen, Leiserson, and Rivest "Introduction to
632 >     * Algorithms" (CLR).
633 >     *
634 >     * TreeBins also maintain a separate locking discipline than
635 >     * regular bins. Because they are forwarded via special MOVED
636 >     * nodes at bin heads (which can never change once established),
637 >     * we cannot use those nodes as locks. Instead, TreeBin
638 >     * extends AbstractQueuedSynchronizer to support a simple form of
639 >     * read-write lock. For update operations and table validation,
640 >     * the exclusive form of lock behaves in the same way as bin-head
641 >     * locks. However, lookups use shared read-lock mechanics to allow
642 >     * multiple readers in the absence of writers.  Additionally,
643 >     * these lookups do not ever block: While the lock is not
644 >     * available, they proceed along the slow traversal path (via
645 >     * next-pointers) until the lock becomes available or the list is
646 >     * exhausted, whichever comes first. (These cases are not fast,
647 >     * but maximize aggregate expected throughput.)  The AQS mechanics
648 >     * for doing this are straightforward.  The lock state is held as
649 >     * AQS getState().  Read counts are negative; the write count (1)
650 >     * is positive.  There are no signalling preferences among readers
651 >     * and writers. Since we don't need to export full Lock API, we
652 >     * just override the minimal AQS methods and use them directly.
653 >     */
654 >    static final class TreeBin extends AbstractQueuedSynchronizer {
655 >        private static final long serialVersionUID = 2249069246763182397L;
656 >        transient TreeNode root;  // root of tree
657 >        transient TreeNode first; // head of next-pointer list
658 >
659 >        /* 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                              }
449                            setTabAt(nextTab, i, lo);
450                            setTabAt(nextTab, i + n, hi);
451                            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;
475 <        h *= 0x85ebca6b;
476 <        h ^= h >>> 13;
477 <        h *= 0xc2b2ae35;
478 <        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
494 <                    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;
1124 >        for (Node[] tab = table;;) {
1125 >            Node f; int i, fh; Object fk;
1126 >            if (tab == null ||
1127 >                (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1128 >                break;
1129 >            else if ((fh = f.hash) == MOVED) {
1130 >                if ((fk = f.key) instanceof TreeBin) {
1131 >                    TreeBin t = (TreeBin)fk;
1132 >                    boolean validated = false;
1133 >                    boolean deleted = false;
1134 >                    t.acquire(0);
1135 >                    try {
1136 >                        if (tabAt(tab, i) == f) {
1137 >                            validated = true;
1138 >                            TreeNode p = t.getTreeNode(h, k, t.root);
1139 >                            if (p != null) {
1140 >                                Object pv = p.val;
1141 >                                if (cv == null || cv == pv || cv.equals(pv)) {
1142 >                                    oldVal = pv;
1143 >                                    if ((p.val = v) == null) {
1144 >                                        deleted = true;
1145 >                                        t.deleteTreeNode(p);
1146 >                                    }
1147 >                                }
1148 >                            }
1149 >                        }
1150 >                    } finally {
1151 >                        t.release(0);
1152 >                    }
1153 >                    if (validated) {
1154 >                        if (deleted)
1155 >                            counter.add(-1L);
1156 >                        break;
1157 >                    }
1158 >                }
1159 >                else
1160 >                    tab = (Node[])fk;
1161 >            }
1162 >            else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1163 >                break;                          // rules out possible existence
1164 >            else if ((fh & LOCKED) != 0) {
1165 >                checkForResize();               // try resizing if can't get lock
1166 >                f.tryAwaitLock(tab, i);
1167 >            }
1168 >            else if (f.casHash(fh, fh | LOCKED)) {
1169 >                boolean validated = false;
1170 >                boolean deleted = false;
1171 >                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 <        Object oldVal = null;               // previous value or null if none
1244 >        int count = 0;
1245          for (Node[] tab = table;;) {
1246 <            Node e; int i; Object ek, ev;
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)
535 <                                    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() >= 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:
563 <     * Replaces node value with v, conditional upon match of cv if
564 <     * non-null.  If resulting value is null, delete.
565 <     */
566 <    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                                  }
599                                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                      }
603                }
604                if (validated) {
605                    if (deleted)
606                        counter.decrement();
607                    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,
616 <                                    MappingFunction<? super K, ? extends V> f,
617 <                                    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 (;;) {
623 <            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                              }
638                        } finally {
639                            if (!added)
640                                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 +                else
1484 +                    tab = (Node[])fk;
1485 +            }
1486 +            else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1487 +                     ((fk = f.key) == k || k.equals(fk)))
1488 +                return fv;
1489 +            else {
1490 +                Node g = f.next;
1491 +                if (g != null) {
1492 +                    for (Node e = g;;) {
1493 +                        Object ek, ev;
1494 +                        if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1495 +                            ((ek = e.key) == k || k.equals(ek)))
1496 +                            return ev;
1497 +                        if ((e = e.next) == null) {
1498 +                            checkForResize();
1499 +                            break;
1500 +                        }
1501 +                    }
1502 +                }
1503 +                if (((fh = f.hash) & LOCKED) != 0) {
1504 +                    checkForResize();
1505 +                    f.tryAwaitLock(tab, i);
1506 +                }
1507 +                else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1508 +                    boolean added = false;
1509 +                    try {
1510 +                        if (tabAt(tab, i) == f) {
1511 +                            count = 1;
1512 +                            for (Node e = f;; ++count) {
1513 +                                Object ek, ev;
1514 +                                if ((e.hash & HASH_BITS) == h &&
1515 +                                    (ev = e.val) != null &&
1516 +                                    ((ek = e.key) == k || k.equals(ek))) {
1517 +                                    val = ev;
1518 +                                    break;
1519 +                                }
1520 +                                Node last = e;
1521 +                                if ((e = e.next) == null) {
1522 +                                    if ((val = mf.apply(k)) != null) {
1523 +                                        added = true;
1524 +                                        last.next = new Node(h, k, val, null);
1525 +                                        if (count >= TREE_THRESHOLD)
1526 +                                            replaceWithTreeBin(tab, i, k);
1527 +                                    }
1528 +                                    break;
1529 +                                }
1530 +                            }
1531 +                        }
1532 +                    } finally {
1533 +                        if (!f.casHash(fh | LOCKED, fh)) {
1534 +                            f.hash = fh;
1535 +                            synchronized (f) { f.notifyAll(); };
1536 +                        }
1537 +                    }
1538 +                    if (count != 0) {
1539 +                        if (!added)
1540 +                            return val;
1541 +                        if (tab.length <= 64)
1542 +                            count = 2;
1543 +                        break;
1544                      }
1545                  }
644                if (validated)
645                    break;
1546              }
1547 <            else if (e.hash < 0)
1548 <                tab = (Node[])e.key;
1549 <            else if (!replace && e.hash == h && (ev = e.val) != null &&
1550 <                     ((ek = e.key) == k || k.equals(ek))) {
1551 <                if (tabAt(tab, i) == e) {
1552 <                    val = (V)ev;
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() >= threshold)
690 <                        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 +     * 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 nodes.
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                  }
729                if (validated)
730                    ++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 encapulate 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 770 | 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 781 | 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
2290 <        final int baseSize;  // initial table size
2289 >        int baseLimit;       // index bound for initial table
2290 >        int baseSize;        // initial table size
2291  
2292          /** Creates iterator for all entries in the table. */
2293 <        InternalIterator(Node[] tab) {
2294 <            this.tab = tab;
2295 <            baseLimit = baseSize = (tab == null) ? 0 : tab.length;
2296 <            index = baseIndex = 0;
2297 <            next = null;
2298 <            advance();
2299 <        }
2300 <
2301 <        /** Creates iterator for the given range of the table */
2302 <        InternalIterator(Node[] tab, int lo, int hi) {
2303 <            this.tab = tab;
2304 <            baseSize = (tab == null) ? 0 : tab.length;
2305 <            baseLimit = (hi <= baseSize) ? hi : baseSize;
2306 <            index = baseIndex = lo;
2307 <            next = null;
2308 <            advance();
2293 >        Traverser(ConcurrentHashMapV8<K, V> map) {
2294 >            this.map = map;
2295 >        }
2296 >
2297 >        /** Creates iterator for split() methods */
2298 >        Traverser(Traverser<K,V,?> it) {
2299 >            ConcurrentHashMapV8<K, V> m; Node[] t;
2300 >            if ((m = this.map = it.map) == null)
2301 >                t = null;
2302 >            else if ((t = it.tab) == null && // force parent tab initialization
2303 >                     (t = it.tab = m.table) != null)
2304 >                it.baseLimit = it.baseSize = t.length;
2305 >            this.tab = t;
2306 >            this.baseSize = it.baseSize;
2307 >            it.baseLimit = this.index = this.baseIndex =
2308 >                ((this.baseLimit = it.baseLimit) + it.baseIndex + 1) >>> 1;
2309          }
2310  
2311 <        /** Advances next. See above for explanation. */
2312 <        final void advance() {
2311 >        /**
2312 >         * Advances next; returns nextVal or null if terminated.
2313 >         * See above for explanation.
2314 >         */
2315 >        final Object advance() {
2316              Node e = last = next;
2317 +            Object ev = null;
2318              outer: do {
2319 <                if (e != null)                   // pass used or skipped node
2319 >                if (e != null)                  // advance past used/skipped node
2320                      e = e.next;
2321 <                while (e == null) {              // get to next non-null bin
2322 <                    Node[] t; int b, i, n;       // checks must use locals
2323 <                    if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2324 <                        (t = tab) == null || i >= (n = t.length))
2321 >                while (e == null) {             // get to next non-null bin
2322 >                    ConcurrentHashMapV8<K, V> m;
2323 >                    Node[] t; int b, i, n; Object ek; // checks must use locals
2324 >                    if ((t = tab) != null)
2325 >                        n = t.length;
2326 >                    else if ((m = map) != null && (t = tab = m.table) != null)
2327 >                        n = baseLimit = baseSize = t.length;
2328 >                    else
2329 >                        break outer;
2330 >                    if ((b = baseIndex) >= baseLimit ||
2331 >                        (i = index) < 0 || i >= n)
2332                          break outer;
2333 <                    else if ((e = tabAt(t, i)) != null && e.hash < 0)
2334 <                        tab = (Node[])e.key;     // restarts due to null val
2335 <                    else                         // visit upper slots if present
2336 <                        index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2333 >                    if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2334 >                        if ((ek = e.key) instanceof TreeBin)
2335 >                            e = ((TreeBin)ek).first;
2336 >                        else {
2337 >                            tab = (Node[])ek;
2338 >                            continue;           // restarts due to null val
2339 >                        }
2340 >                    }                           // visit upper slots if present
2341 >                    index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2342                  }
2343                  nextKey = e.key;
2344 <            } while ((nextVal = e.val) == null); // skip deleted or special nodes
2344 >            } while ((ev = e.val) == null);    // skip deleted or special nodes
2345              next = e;
2346 +            return nextVal = ev;
2347 +        }
2348 +
2349 +        public final void remove() {
2350 +            if (nextVal == null && last == null)
2351 +                advance();
2352 +            Node e = last;
2353 +            if (e == null)
2354 +                throw new IllegalStateException();
2355 +            last = null;
2356 +            map.remove(e.key);
2357 +        }
2358 +
2359 +        public final boolean hasNext() {
2360 +            return nextVal != null || advance() != null;
2361          }
2362 +
2363 +        public final boolean hasMoreElements() { return hasNext(); }
2364 +        public final void setRawResult(Object x) { }
2365 +        public R getRawResult() { return null; }
2366 +        public boolean exec() { return true; }
2367      }
2368  
2369      /* ---------------- Public operations -------------- */
2370  
2371      /**
2372 <     * Creates a new, empty map with the specified initial
832 <     * capacity, load factor and concurrency level.
833 <     *
834 <     * @param initialCapacity the initial capacity. The implementation
835 <     * performs internal sizing to accommodate this many elements.
836 <     * @param loadFactor  the load factor threshold, used to control resizing.
837 <     * Resizing may be performed when the average number of elements per
838 <     * bin exceeds this threshold.
839 <     * @param concurrencyLevel the estimated number of concurrently
840 <     * updating threads. The implementation may use this value as
841 <     * a sizing hint.
842 <     * @throws IllegalArgumentException if the initial capacity is
843 <     * negative or the load factor or concurrencyLevel are
844 <     * nonpositive.
2372 >     * Creates a new, empty map with the default initial table size (16).
2373       */
2374 <    public ConcurrentHashMapV8(int initialCapacity,
847 <                               float loadFactor, int concurrencyLevel) {
848 <        if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
849 <            throw new IllegalArgumentException();
850 <        int cap = tableSizeFor(initialCapacity);
2374 >    public ConcurrentHashMapV8() {
2375          this.counter = new LongAdder();
852        this.loadFactor = loadFactor;
853        this.targetCapacity = cap;
2376      }
2377  
2378      /**
2379 <     * Creates a new, empty map with the specified initial capacity
2380 <     * and load factor and with the default concurrencyLevel (16).
2379 >     * Creates a new, empty map with an initial table size
2380 >     * accommodating the specified number of elements without the need
2381 >     * to dynamically resize.
2382       *
2383       * @param initialCapacity The implementation performs internal
2384       * sizing to accommodate this many elements.
862     * @param loadFactor  the load factor threshold, used to control resizing.
863     * Resizing may be performed when the average number of elements per
864     * bin exceeds this threshold.
2385       * @throws IllegalArgumentException if the initial capacity of
2386 <     * elements is negative or the load factor is nonpositive
867 <     *
868 <     * @since 1.6
2386 >     * elements is negative
2387       */
2388 <    public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2389 <        this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2388 >    public ConcurrentHashMapV8(int initialCapacity) {
2389 >        if (initialCapacity < 0)
2390 >            throw new IllegalArgumentException();
2391 >        int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2392 >                   MAXIMUM_CAPACITY :
2393 >                   tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2394 >        this.counter = new LongAdder();
2395 >        this.sizeCtl = cap;
2396      }
2397  
2398      /**
2399 <     * Creates a new, empty map with the specified initial capacity,
876 <     * and with default load factor (0.75) and concurrencyLevel (16).
2399 >     * Creates a new map with the same mappings as the given map.
2400       *
2401 <     * @param initialCapacity the initial capacity. The implementation
879 <     * performs internal sizing to accommodate this many elements.
880 <     * @throws IllegalArgumentException if the initial capacity of
881 <     * elements is negative.
2401 >     * @param m the map
2402       */
2403 <    public ConcurrentHashMapV8(int initialCapacity) {
2404 <        this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2403 >    public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2404 >        this.counter = new LongAdder();
2405 >        this.sizeCtl = DEFAULT_CAPACITY;
2406 >        internalPutAll(m);
2407      }
2408  
2409      /**
2410 <     * Creates a new, empty map with a default initial capacity (16),
2411 <     * load factor (0.75) and concurrencyLevel (16).
2410 >     * Creates a new, empty map with an initial table size based on
2411 >     * the given number of elements ({@code initialCapacity}) and
2412 >     * initial table density ({@code loadFactor}).
2413 >     *
2414 >     * @param initialCapacity the initial capacity. The implementation
2415 >     * performs internal sizing to accommodate this many elements,
2416 >     * given the specified load factor.
2417 >     * @param loadFactor the load factor (table density) for
2418 >     * establishing the initial table size
2419 >     * @throws IllegalArgumentException if the initial capacity of
2420 >     * elements is negative or the load factor is nonpositive
2421 >     *
2422 >     * @since 1.6
2423       */
2424 <    public ConcurrentHashMapV8() {
2425 <        this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2424 >    public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2425 >        this(initialCapacity, loadFactor, 1);
2426      }
2427  
2428      /**
2429 <     * Creates a new map with the same mappings as the given map.
2430 <     * The map is created with a capacity of 1.5 times the number
2431 <     * of mappings in the given map or 16 (whichever is greater),
2432 <     * and a default load factor (0.75) and concurrencyLevel (16).
2429 >     * Creates a new, empty map with an initial table size based on
2430 >     * the given number of elements ({@code initialCapacity}), table
2431 >     * density ({@code loadFactor}), and number of concurrently
2432 >     * updating threads ({@code concurrencyLevel}).
2433       *
2434 <     * @param m the map
2434 >     * @param initialCapacity the initial capacity. The implementation
2435 >     * performs internal sizing to accommodate this many elements,
2436 >     * given the specified load factor.
2437 >     * @param loadFactor the load factor (table density) for
2438 >     * establishing the initial table size
2439 >     * @param concurrencyLevel the estimated number of concurrently
2440 >     * updating threads. The implementation may use this value as
2441 >     * a sizing hint.
2442 >     * @throws IllegalArgumentException if the initial capacity is
2443 >     * negative or the load factor or concurrencyLevel are
2444 >     * nonpositive
2445       */
2446 <    public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2447 <        this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2448 <        putAll(m);
2446 >    public ConcurrentHashMapV8(int initialCapacity,
2447 >                               float loadFactor, int concurrencyLevel) {
2448 >        if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2449 >            throw new IllegalArgumentException();
2450 >        if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2451 >            initialCapacity = concurrencyLevel;   // as estimated threads
2452 >        long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2453 >        int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2454 >            MAXIMUM_CAPACITY : tableSizeFor((int)size);
2455 >        this.counter = new LongAdder();
2456 >        this.sizeCtl = cap;
2457      }
2458  
2459      /**
# Line 923 | Line 2474 | public class ConcurrentHashMapV8<K, V>
2474      }
2475  
2476      /**
2477 +     * Returns the number of mappings. This method should be used
2478 +     * instead of {@link #size} because a ConcurrentHashMap may
2479 +     * contain more mappings than can be represented as an int. The
2480 +     * value returned is a snapshot; the actual count may differ if
2481 +     * there are ongoing concurrent insertions or removals.
2482 +     *
2483 +     * @return the number of mappings
2484 +     */
2485 +    public long mappingCount() {
2486 +        long n = counter.sum();
2487 +        return (n < 0L) ? 0L : n; // ignore transient negative values
2488 +    }
2489 +
2490 +    /**
2491       * Returns the value to which the specified key is mapped,
2492       * or {@code null} if this map contains no mapping for the key.
2493       *
# Line 933 | Line 2498 | public class ConcurrentHashMapV8<K, V>
2498       *
2499       * @throws NullPointerException if the specified key is null
2500       */
2501 <    @SuppressWarnings("unchecked")
937 <    public V get(Object key) {
2501 >    @SuppressWarnings("unchecked") public V get(Object key) {
2502          if (key == null)
2503              throw new NullPointerException();
2504          return (V)internalGet(key);
2505      }
2506  
2507      /**
2508 +     * Returns the value to which the specified key is mapped,
2509 +     * or the gieven defaultValue if this map contains no mapping for the key.
2510 +     *
2511 +     * @param key the key
2512 +     * @param defaultValue the value to return if this map contains
2513 +     * no mapping for the given key.
2514 +     * @return the mapping for the key, if present; else the defaultValue
2515 +     * @throws NullPointerException if the specified key is null
2516 +     */
2517 +    @SuppressWarnings("unchecked") public V getValueOrDefault(Object key, V defaultValue) {
2518 +        if (key == null)
2519 +            throw new NullPointerException();
2520 +        V v = (V) internalGet(key);
2521 +        return v == null ? defaultValue : v;
2522 +    }
2523 +
2524 +    /**
2525       * Tests if the specified object is a key in this table.
2526       *
2527       * @param  key   possible key
2528       * @return {@code true} if and only if the specified object
2529       *         is a key in this table, as determined by the
2530 <     *         {@code equals} method; {@code false} otherwise.
2530 >     *         {@code equals} method; {@code false} otherwise
2531       * @throws NullPointerException if the specified key is null
2532       */
2533      public boolean containsKey(Object key) {
# Line 969 | Line 2550 | public class ConcurrentHashMapV8<K, V>
2550          if (value == null)
2551              throw new NullPointerException();
2552          Object v;
2553 <        InternalIterator it = new InternalIterator(table);
2554 <        while (it.next != null) {
2555 <            if ((v = it.nextVal) == value || value.equals(v))
2553 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2554 >        while ((v = it.advance()) != null) {
2555 >            if (v == value || value.equals(v))
2556                  return true;
976            it.advance();
2557          }
2558          return false;
2559      }
# Line 1010 | Line 2590 | public class ConcurrentHashMapV8<K, V>
2590       *         {@code null} if there was no mapping for {@code key}
2591       * @throws NullPointerException if the specified key or value is null
2592       */
2593 <    @SuppressWarnings("unchecked")
1014 <    public V put(K key, V value) {
2593 >    @SuppressWarnings("unchecked") public V put(K key, V value) {
2594          if (key == null || value == null)
2595              throw new NullPointerException();
2596 <        return (V)internalPut(key, value, true);
2596 >        return (V)internalPut(key, value);
2597      }
2598  
2599      /**
# Line 1024 | Line 2603 | public class ConcurrentHashMapV8<K, V>
2603       *         or {@code null} if there was no mapping for the key
2604       * @throws NullPointerException if the specified key or value is null
2605       */
2606 <    @SuppressWarnings("unchecked")
1028 <    public V putIfAbsent(K key, V value) {
2606 >    @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
2607          if (key == null || value == null)
2608              throw new NullPointerException();
2609 <        return (V)internalPut(key, value, false);
2609 >        return (V)internalPutIfAbsent(key, value);
2610      }
2611  
2612      /**
# Line 1039 | Line 2617 | public class ConcurrentHashMapV8<K, V>
2617       * @param m mappings to be stored in this map
2618       */
2619      public void putAll(Map<? extends K, ? extends V> m) {
2620 <        if (m == null)
1043 <            throw new NullPointerException();
1044 <        /*
1045 <         * If uninitialized, try to adjust targetCapacity to
1046 <         * accommodate the given number of elements.
1047 <         */
1048 <        if (table == null) {
1049 <            int size = m.size();
1050 <            int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1051 <                tableSizeFor(size + (size >>> 1));
1052 <            if (cap > targetCapacity)
1053 <                targetCapacity = cap;
1054 <        }
1055 <        for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1056 <            put(e.getKey(), e.getValue());
2620 >        internalPutAll(m);
2621      }
2622  
2623      /**
2624       * If the specified key is not already associated with a value,
2625 <     * computes its value using the given mappingFunction, and if
2626 <     * non-null, enters it into the map.  This is equivalent to
2627 <     *  <pre> {@code
2625 >     * computes its value using the given mappingFunction and enters
2626 >     * it into the map unless null.  This is equivalent to
2627 >     * <pre> {@code
2628       * if (map.containsKey(key))
2629       *   return map.get(key);
2630 <     * value = mappingFunction.map(key);
2630 >     * value = mappingFunction.apply(key);
2631       * if (value != null)
2632       *   map.put(key, value);
2633       * return value;}</pre>
2634       *
2635 <     * except that the action is performed atomically.  Some attempted
2636 <     * update operations on this map by other threads may be blocked
2637 <     * while computation is in progress, so the computation should be
2638 <     * short and simple, and must not attempt to update any other
2639 <     * mappings of this Map. The most appropriate usage is to
2635 >     * except that the action is performed atomically.  If the
2636 >     * function returns {@code null} no mapping is recorded. If the
2637 >     * function itself throws an (unchecked) exception, the exception
2638 >     * is rethrown to its caller, and no mapping is recorded.  Some
2639 >     * attempted update operations on this map by other threads may be
2640 >     * blocked while computation is in progress, so the computation
2641 >     * should be short and simple, and must not attempt to update any
2642 >     * other mappings of this Map. The most appropriate usage is to
2643       * construct a new object serving as an initial mapped value, or
2644       * memoized result, as in:
2645 +     *
2646       *  <pre> {@code
2647 <     * map.computeIfAbsent(key, new MappingFunction<K, V>() {
2647 >     * map.computeIfAbsent(key, new Fun<K, V>() {
2648       *   public V map(K k) { return new Value(f(k)); }});}</pre>
2649       *
2650       * @param key key with which the specified value is to be associated
2651       * @param mappingFunction the function to compute a value
2652       * @return the current (existing or computed) value associated with
2653 <     *         the specified key, or {@code null} if the computation
1086 <     *         returned {@code null}.
2653 >     *         the specified key, or null if the computed value is null.
2654       * @throws NullPointerException if the specified key or mappingFunction
2655 <     *         is null,
2655 >     *         is null
2656       * @throws IllegalStateException if the computation detectably
2657       *         attempts a recursive update to this map that would
2658 <     *         otherwise never complete.
2658 >     *         otherwise never complete
2659       * @throws RuntimeException or Error if the mappingFunction does so,
2660 <     *         in which case the mapping is left unestablished.
2660 >     *         in which case the mapping is left unestablished
2661       */
2662 <    public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2662 >    @SuppressWarnings("unchecked") public V computeIfAbsent
2663 >        (K key, Fun<? super K, ? extends V> mappingFunction) {
2664          if (key == null || mappingFunction == null)
2665              throw new NullPointerException();
2666 <        return internalCompute(key, mappingFunction, false);
2666 >        return (V)internalComputeIfAbsent(key, mappingFunction);
2667      }
2668  
2669      /**
2670 <     * Computes the value associated with the given key using the given
2671 <     * mappingFunction, and if non-null, enters it into the map.  This
1104 <     * is equivalent to
2670 >     * If the given key is present, computes a new mapping value given a key and
2671 >     * its current mapped value. This is equivalent to
2672       *  <pre> {@code
2673 <     * value = mappingFunction.map(key);
2674 <     * if (value != null)
2675 <     *   map.put(key, value);
2676 <     * else
2677 <     *   value = map.get(key);
2678 <     * return value;}</pre>
2673 >     *   if (map.containsKey(key)) {
2674 >     *     value = remappingFunction.apply(key, map.get(key));
2675 >     *     if (value != null)
2676 >     *       map.put(key, value);
2677 >     *     else
2678 >     *       map.remove(key);
2679 >     *   }
2680 >     * }</pre>
2681 >     *
2682 >     * except that the action is performed atomically.  If the
2683 >     * function returns {@code null}, the mapping is removed.  If the
2684 >     * function itself throws an (unchecked) exception, the exception
2685 >     * is rethrown to its caller, and the current mapping is left
2686 >     * unchanged.  Some attempted update operations on this map by
2687 >     * other threads may be blocked while computation is in progress,
2688 >     * so the computation should be short and simple, and must not
2689 >     * attempt to update any other mappings of this Map. For example,
2690 >     * to either create or append new messages to a value mapping:
2691       *
2692 <     * except that the action is performed atomically.  Some attempted
2693 <     * update operations on this map by other threads may be blocked
2694 <     * while computation is in progress, so the computation should be
2695 <     * short and simple, and must not attempt to update any other
2696 <     * mappings of this Map.
2692 >     * @param key key with which the specified value is to be associated
2693 >     * @param remappingFunction the function to compute a value
2694 >     * @return the new value associated with the specified key, or null if none
2695 >     * @throws NullPointerException if the specified key or remappingFunction
2696 >     *         is null
2697 >     * @throws IllegalStateException if the computation detectably
2698 >     *         attempts a recursive update to this map that would
2699 >     *         otherwise never complete
2700 >     * @throws RuntimeException or Error if the remappingFunction does so,
2701 >     *         in which case the mapping is unchanged
2702 >     */
2703 >    @SuppressWarnings("unchecked") public V computeIfPresent
2704 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2705 >        if (key == null || remappingFunction == null)
2706 >            throw new NullPointerException();
2707 >        return (V)internalCompute(key, true, remappingFunction);
2708 >    }
2709 >
2710 >    /**
2711 >     * Computes a new mapping value given a key and
2712 >     * its current mapped value (or {@code null} if there is no current
2713 >     * mapping). This is equivalent to
2714 >     *  <pre> {@code
2715 >     *   value = remappingFunction.apply(key, map.get(key));
2716 >     *   if (value != null)
2717 >     *     map.put(key, value);
2718 >     *   else
2719 >     *     map.remove(key);
2720 >     * }</pre>
2721 >     *
2722 >     * except that the action is performed atomically.  If the
2723 >     * function returns {@code null}, the mapping is removed.  If the
2724 >     * function itself throws an (unchecked) exception, the exception
2725 >     * is rethrown to its caller, and the current mapping is left
2726 >     * unchanged.  Some attempted update operations on this map by
2727 >     * other threads may be blocked while computation is in progress,
2728 >     * so the computation should be short and simple, and must not
2729 >     * attempt to update any other mappings of this Map. For example,
2730 >     * to either create or append new messages to a value mapping:
2731 >     *
2732 >     * <pre> {@code
2733 >     * Map<Key, String> map = ...;
2734 >     * final String msg = ...;
2735 >     * map.compute(key, new BiFun<Key, String, String>() {
2736 >     *   public String apply(Key k, String v) {
2737 >     *    return (v == null) ? msg : v + msg;});}}</pre>
2738       *
2739       * @param key key with which the specified value is to be associated
2740 <     * @param mappingFunction the function to compute a value
2741 <     * @return the current value associated with
2742 <     *         the specified key, or {@code null} if the computation
2743 <     *         returned {@code null} and the value was not otherwise present.
1124 <     * @throws NullPointerException if the specified key or mappingFunction
1125 <     *         is null,
2740 >     * @param remappingFunction the function to compute a value
2741 >     * @return the new value associated with the specified key, or null if none
2742 >     * @throws NullPointerException if the specified key or remappingFunction
2743 >     *         is null
2744       * @throws IllegalStateException if the computation detectably
2745       *         attempts a recursive update to this map that would
2746 <     *         otherwise never complete.
2747 <     * @throws RuntimeException or Error if the mappingFunction does so,
2748 <     *         in which case the mapping is unchanged.
2749 <     */
2750 <    public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2751 <        if (key == null || mappingFunction == null)
2746 >     *         otherwise never complete
2747 >     * @throws RuntimeException or Error if the remappingFunction does so,
2748 >     *         in which case the mapping is unchanged
2749 >     */
2750 >    @SuppressWarnings("unchecked") public V compute
2751 >        (K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2752 >        if (key == null || remappingFunction == null)
2753              throw new NullPointerException();
2754 <        return internalCompute(key, mappingFunction, true);
2754 >        return (V)internalCompute(key, false, remappingFunction);
2755 >    }
2756 >
2757 >    /**
2758 >     * If the specified key is not already associated
2759 >     * with a value, associate it with the given value.
2760 >     * Otherwise, replace the value with the results of
2761 >     * the given remapping function. This is equivalent to:
2762 >     *  <pre> {@code
2763 >     *   if (!map.containsKey(key))
2764 >     *     map.put(value);
2765 >     *   else {
2766 >     *     newValue = remappingFunction.apply(map.get(key), value);
2767 >     *     if (value != null)
2768 >     *       map.put(key, value);
2769 >     *     else
2770 >     *       map.remove(key);
2771 >     *   }
2772 >     * }</pre>
2773 >     * except that the action is performed atomically.  If the
2774 >     * function returns {@code null}, the mapping is removed.  If the
2775 >     * function itself throws an (unchecked) exception, the exception
2776 >     * is rethrown to its caller, and the current mapping is left
2777 >     * unchanged.  Some attempted update operations on this map by
2778 >     * other threads may be blocked while computation is in progress,
2779 >     * so the computation should be short and simple, and must not
2780 >     * attempt to update any other mappings of this Map.
2781 >     */
2782 >    @SuppressWarnings("unchecked") public V merge
2783 >        (K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
2784 >        if (key == null || value == null || remappingFunction == null)
2785 >            throw new NullPointerException();
2786 >        return (V)internalMerge(key, value, remappingFunction);
2787      }
2788  
2789      /**
# Line 1144 | Line 2795 | public class ConcurrentHashMapV8<K, V>
2795       *         {@code null} if there was no mapping for {@code key}
2796       * @throws NullPointerException if the specified key is null
2797       */
2798 <    @SuppressWarnings("unchecked")
1148 <    public V remove(Object key) {
2798 >    @SuppressWarnings("unchecked") public V remove(Object key) {
2799          if (key == null)
2800              throw new NullPointerException();
2801          return (V)internalReplace(key, null, null);
# Line 1182 | Line 2832 | public class ConcurrentHashMapV8<K, V>
2832       *         or {@code null} if there was no mapping for the key
2833       * @throws NullPointerException if the specified key or value is null
2834       */
2835 <    @SuppressWarnings("unchecked")
1186 <    public V replace(K key, V value) {
2835 >    @SuppressWarnings("unchecked") public V replace(K key, V value) {
2836          if (key == null || value == null)
2837              throw new NullPointerException();
2838          return (V)internalReplace(key, value, null);
# Line 1280 | Line 2929 | public class ConcurrentHashMapV8<K, V>
2929      }
2930  
2931      /**
2932 +     * Returns a partitionable iterator of the keys in this map.
2933 +     *
2934 +     * @return a partitionable iterator of the keys in this map
2935 +     */
2936 +    public Spliterator<K> keySpliterator() {
2937 +        return new KeyIterator<K,V>(this);
2938 +    }
2939 +
2940 +    /**
2941 +     * Returns a partitionable iterator of the values in this map.
2942 +     *
2943 +     * @return a partitionable iterator of the values in this map
2944 +     */
2945 +    public Spliterator<V> valueSpliterator() {
2946 +        return new ValueIterator<K,V>(this);
2947 +    }
2948 +
2949 +    /**
2950 +     * Returns a partitionable iterator of the entries in this map.
2951 +     *
2952 +     * @return a partitionable iterator of the entries in this map
2953 +     */
2954 +    public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2955 +        return new EntryIterator<K,V>(this);
2956 +    }
2957 +
2958 +    /**
2959       * Returns the hash code value for this {@link Map}, i.e.,
2960       * the sum of, for each key-value pair in the map,
2961       * {@code key.hashCode() ^ value.hashCode()}.
# Line 1288 | Line 2964 | public class ConcurrentHashMapV8<K, V>
2964       */
2965      public int hashCode() {
2966          int h = 0;
2967 <        InternalIterator it = new InternalIterator(table);
2968 <        while (it.next != null) {
2969 <            h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
2970 <            it.advance();
2967 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2968 >        Object v;
2969 >        while ((v = it.advance()) != null) {
2970 >            h += it.nextKey.hashCode() ^ v.hashCode();
2971          }
2972          return h;
2973      }
# Line 1308 | Line 2984 | public class ConcurrentHashMapV8<K, V>
2984       * @return a string representation of this map
2985       */
2986      public String toString() {
2987 <        InternalIterator it = new InternalIterator(table);
2987 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2988          StringBuilder sb = new StringBuilder();
2989          sb.append('{');
2990 <        if (it.next != null) {
2990 >        Object v;
2991 >        if ((v = it.advance()) != null) {
2992              for (;;) {
2993 <                Object k = it.nextKey, v = it.nextVal;
2993 >                Object k = it.nextKey;
2994                  sb.append(k == this ? "(this Map)" : k);
2995                  sb.append('=');
2996                  sb.append(v == this ? "(this Map)" : v);
2997 <                it.advance();
1321 <                if (it.next == null)
2997 >                if ((v = it.advance()) == null)
2998                      break;
2999                  sb.append(',').append(' ');
3000              }
# Line 1341 | Line 3017 | public class ConcurrentHashMapV8<K, V>
3017              if (!(o instanceof Map))
3018                  return false;
3019              Map<?,?> m = (Map<?,?>) o;
3020 <            InternalIterator it = new InternalIterator(table);
3021 <            while (it.next != null) {
3022 <                Object val = it.nextVal;
3020 >            Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3021 >            Object val;
3022 >            while ((val = it.advance()) != null) {
3023                  Object v = m.get(it.nextKey);
3024                  if (v == null || (v != val && !v.equals(val)))
3025                      return false;
1350                it.advance();
3026              }
3027              for (Map.Entry<?,?> e : m.entrySet()) {
3028                  Object mk, mv, v;
# Line 1363 | Line 3038 | public class ConcurrentHashMapV8<K, V>
3038  
3039      /* ----------------Iterators -------------- */
3040  
3041 <    /**
3042 <     * Base class for key, value, and entry iterators.  Adds a map
3043 <     * reference to InternalIterator to support Iterator.remove.
3044 <     */
3045 <    static abstract class ViewIterator<K,V> extends InternalIterator {
1371 <        final ConcurrentHashMapV8<K, V> map;
1372 <        ViewIterator(ConcurrentHashMapV8<K, V> map) {
1373 <            super(map.table);
1374 <            this.map = map;
3041 >    @SuppressWarnings("serial") static final class KeyIterator<K,V> extends Traverser<K,V,Object>
3042 >        implements Spliterator<K>, Enumeration<K> {
3043 >        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3044 >        KeyIterator(Traverser<K,V,Object> it) {
3045 >            super(it);
3046          }
3047 <
3048 <        public final void remove() {
1378 <            if (last == null)
3047 >        public KeyIterator<K,V> split() {
3048 >            if (last != null || (next != null && nextVal == null))
3049                  throw new IllegalStateException();
3050 <            map.remove(last.key);
1381 <            last = null;
3050 >            return new KeyIterator<K,V>(this);
3051          }
3052 <
3053 <        public final boolean hasNext()         { return next != null; }
1385 <        public final boolean hasMoreElements() { return next != null; }
1386 <    }
1387 <
1388 <    static final class KeyIterator<K,V> extends ViewIterator<K,V>
1389 <        implements Iterator<K>, Enumeration<K> {
1390 <        KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1391 <
1392 <        @SuppressWarnings("unchecked")
1393 <        public final K next() {
1394 <            if (next == null)
3052 >        @SuppressWarnings("unchecked") public final K next() {
3053 >            if (nextVal == null && advance() == null)
3054                  throw new NoSuchElementException();
3055              Object k = nextKey;
3056 <            advance();
3057 <            return (K)k;
3056 >            nextVal = null;
3057 >            return (K) k;
3058          }
3059  
3060          public final K nextElement() { return next(); }
3061      }
3062  
3063 <    static final class ValueIterator<K,V> extends ViewIterator<K,V>
3064 <        implements Iterator<V>, Enumeration<V> {
3063 >    @SuppressWarnings("serial") static final class ValueIterator<K,V> extends Traverser<K,V,Object>
3064 >        implements Spliterator<V>, Enumeration<V> {
3065          ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3066 +        ValueIterator(Traverser<K,V,Object> it) {
3067 +            super(it);
3068 +        }
3069 +        public ValueIterator<K,V> split() {
3070 +            if (last != null || (next != null && nextVal == null))
3071 +                throw new IllegalStateException();
3072 +            return new ValueIterator<K,V>(this);
3073 +        }
3074  
3075 <        @SuppressWarnings("unchecked")
3076 <        public final V next() {
3077 <            if (next == null)
3075 >        @SuppressWarnings("unchecked") public final V next() {
3076 >            Object v;
3077 >            if ((v = nextVal) == null && (v = advance()) == null)
3078                  throw new NoSuchElementException();
3079 <            Object v = nextVal;
3080 <            advance();
1414 <            return (V)v;
3079 >            nextVal = null;
3080 >            return (V) v;
3081          }
3082  
3083          public final V nextElement() { return next(); }
3084      }
3085  
3086 <    static final class EntryIterator<K,V> extends ViewIterator<K,V>
3087 <        implements Iterator<Map.Entry<K,V>> {
3086 >    @SuppressWarnings("serial") static final class EntryIterator<K,V> extends Traverser<K,V,Object>
3087 >        implements Spliterator<Map.Entry<K,V>> {
3088          EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
3089 +        EntryIterator(Traverser<K,V,Object> it) {
3090 +            super(it);
3091 +        }
3092 +        public EntryIterator<K,V> split() {
3093 +            if (last != null || (next != null && nextVal == null))
3094 +                throw new IllegalStateException();
3095 +            return new EntryIterator<K,V>(this);
3096 +        }
3097  
3098 <        @SuppressWarnings("unchecked")
3099 <        public final Map.Entry<K,V> next() {
3100 <            if (next == null)
3098 >        @SuppressWarnings("unchecked") public final Map.Entry<K,V> next() {
3099 >            Object v;
3100 >            if ((v = nextVal) == null && (v = advance()) == null)
3101                  throw new NoSuchElementException();
3102              Object k = nextKey;
3103 <            Object v = nextVal;
3104 <            advance();
1431 <            return new WriteThroughEntry<K,V>(map, (K)k, (V)v);
3103 >            nextVal = null;
3104 >            return new MapEntry<K,V>((K)k, (V)v, map);
3105          }
3106      }
3107  
3108      /**
3109 <     * Custom Entry class used by EntryIterator.next(), that relays
1437 <     * setValue changes to the underlying map.
3109 >     * Exported Entry for iterators
3110       */
3111 <    static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> {
1440 <        final ConcurrentHashMapV8<K, V> map;
3111 >    static final class MapEntry<K,V> implements Map.Entry<K, V> {
3112          final K key; // non-null
3113          V val;       // non-null
3114 <        WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) {
3115 <            this.map = map; this.key = key; this.val = val;
3114 >        final ConcurrentHashMapV8<K, V> map;
3115 >        MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
3116 >            this.key = key;
3117 >            this.val = val;
3118 >            this.map = map;
3119          }
1446
3120          public final K getKey()       { return key; }
3121          public final V getValue()     { return val; }
3122          public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
# Line 1460 | Line 3133 | public class ConcurrentHashMapV8<K, V>
3133  
3134          /**
3135           * Sets our entry's value and writes through to the map. The
3136 <         * value to return is somewhat arbitrary here. Since a
3137 <         * WriteThroughEntry does not necessarily track asynchronous
3138 <         * changes, the most recent "previous" value could be
3139 <         * different from what we return (or could even have been
3140 <         * removed in which case the put will re-establish). We do not
1468 <         * and cannot guarantee more.
3136 >         * value to return is somewhat arbitrary here. Since we do not
3137 >         * necessarily track asynchronous changes, the most recent
3138 >         * "previous" value could be different from what we return (or
3139 >         * could even have been removed in which case the put will
3140 >         * re-establish). We do not and cannot guarantee more.
3141           */
3142          public final V setValue(V value) {
3143              if (value == null) throw new NullPointerException();
# Line 1478 | Line 3150 | public class ConcurrentHashMapV8<K, V>
3150  
3151      /* ----------------Views -------------- */
3152  
3153 <    /*
3154 <     * These currently just extend java.util.AbstractX classes, but
1483 <     * may need a new custom base to support partitioned traversal.
3153 >    /**
3154 >     * Base class for views.
3155       */
3156 <
1486 <    static final class KeySet<K,V> extends AbstractSet<K> {
3156 >    static abstract class CHMView<K, V> {
3157          final ConcurrentHashMapV8<K, V> map;
3158 <        KeySet(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1489 <
3158 >        CHMView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
3159          public final int size()                 { return map.size(); }
3160          public final boolean isEmpty()          { return map.isEmpty(); }
3161          public final void clear()               { map.clear(); }
3162 +
3163 +        // implementations below rely on concrete classes supplying these
3164 +        abstract public Iterator<?> iterator();
3165 +        abstract public boolean contains(Object o);
3166 +        abstract public boolean remove(Object o);
3167 +
3168 +        private static final String oomeMsg = "Required array size too large";
3169 +
3170 +        public final Object[] toArray() {
3171 +            long sz = map.mappingCount();
3172 +            if (sz > (long)(MAX_ARRAY_SIZE))
3173 +                throw new OutOfMemoryError(oomeMsg);
3174 +            int n = (int)sz;
3175 +            Object[] r = new Object[n];
3176 +            int i = 0;
3177 +            Iterator<?> it = iterator();
3178 +            while (it.hasNext()) {
3179 +                if (i == n) {
3180 +                    if (n >= MAX_ARRAY_SIZE)
3181 +                        throw new OutOfMemoryError(oomeMsg);
3182 +                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3183 +                        n = MAX_ARRAY_SIZE;
3184 +                    else
3185 +                        n += (n >>> 1) + 1;
3186 +                    r = Arrays.copyOf(r, n);
3187 +                }
3188 +                r[i++] = it.next();
3189 +            }
3190 +            return (i == n) ? r : Arrays.copyOf(r, i);
3191 +        }
3192 +
3193 +        @SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
3194 +            long sz = map.mappingCount();
3195 +            if (sz > (long)(MAX_ARRAY_SIZE))
3196 +                throw new OutOfMemoryError(oomeMsg);
3197 +            int m = (int)sz;
3198 +            T[] r = (a.length >= m) ? a :
3199 +                (T[])java.lang.reflect.Array
3200 +                .newInstance(a.getClass().getComponentType(), m);
3201 +            int n = r.length;
3202 +            int i = 0;
3203 +            Iterator<?> it = iterator();
3204 +            while (it.hasNext()) {
3205 +                if (i == n) {
3206 +                    if (n >= MAX_ARRAY_SIZE)
3207 +                        throw new OutOfMemoryError(oomeMsg);
3208 +                    if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3209 +                        n = MAX_ARRAY_SIZE;
3210 +                    else
3211 +                        n += (n >>> 1) + 1;
3212 +                    r = Arrays.copyOf(r, n);
3213 +                }
3214 +                r[i++] = (T)it.next();
3215 +            }
3216 +            if (a == r && i < n) {
3217 +                r[i] = null; // null-terminate
3218 +                return r;
3219 +            }
3220 +            return (i == n) ? r : Arrays.copyOf(r, i);
3221 +        }
3222 +
3223 +        public final int hashCode() {
3224 +            int h = 0;
3225 +            for (Iterator<?> it = iterator(); it.hasNext();)
3226 +                h += it.next().hashCode();
3227 +            return h;
3228 +        }
3229 +
3230 +        public final String toString() {
3231 +            StringBuilder sb = new StringBuilder();
3232 +            sb.append('[');
3233 +            Iterator<?> it = iterator();
3234 +            if (it.hasNext()) {
3235 +                for (;;) {
3236 +                    Object e = it.next();
3237 +                    sb.append(e == this ? "(this Collection)" : e);
3238 +                    if (!it.hasNext())
3239 +                        break;
3240 +                    sb.append(',').append(' ');
3241 +                }
3242 +            }
3243 +            return sb.append(']').toString();
3244 +        }
3245 +
3246 +        public final boolean containsAll(Collection<?> c) {
3247 +            if (c != this) {
3248 +                for (Iterator<?> it = c.iterator(); it.hasNext();) {
3249 +                    Object e = it.next();
3250 +                    if (e == null || !contains(e))
3251 +                        return false;
3252 +                }
3253 +            }
3254 +            return true;
3255 +        }
3256 +
3257 +        public final boolean removeAll(Collection<?> c) {
3258 +            boolean modified = false;
3259 +            for (Iterator<?> it = iterator(); it.hasNext();) {
3260 +                if (c.contains(it.next())) {
3261 +                    it.remove();
3262 +                    modified = true;
3263 +                }
3264 +            }
3265 +            return modified;
3266 +        }
3267 +
3268 +        public final boolean retainAll(Collection<?> c) {
3269 +            boolean modified = false;
3270 +            for (Iterator<?> it = iterator(); it.hasNext();) {
3271 +                if (!c.contains(it.next())) {
3272 +                    it.remove();
3273 +                    modified = true;
3274 +                }
3275 +            }
3276 +            return modified;
3277 +        }
3278 +
3279 +    }
3280 +
3281 +    static final class KeySet<K,V> extends CHMView<K,V> implements Set<K> {
3282 +        KeySet(ConcurrentHashMapV8<K, V> map)  {
3283 +            super(map);
3284 +        }
3285          public final boolean contains(Object o) { return map.containsKey(o); }
3286          public final boolean remove(Object o)   { return map.remove(o) != null; }
3287          public final Iterator<K> iterator() {
3288              return new KeyIterator<K,V>(map);
3289          }
3290 +        public final boolean add(K e) {
3291 +            throw new UnsupportedOperationException();
3292 +        }
3293 +        public final boolean addAll(Collection<? extends K> c) {
3294 +            throw new UnsupportedOperationException();
3295 +        }
3296 +        public boolean equals(Object o) {
3297 +            Set<?> c;
3298 +            return ((o instanceof Set) &&
3299 +                    ((c = (Set<?>)o) == this ||
3300 +                     (containsAll(c) && c.containsAll(this))));
3301 +        }
3302      }
3303  
1500    static final class Values<K,V> extends AbstractCollection<V> {
1501        final ConcurrentHashMapV8<K, V> map;
1502        Values(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
3304  
3305 <        public final int size()                 { return map.size(); }
3306 <        public final boolean isEmpty()          { return map.isEmpty(); }
3307 <        public final void clear()               { map.clear(); }
3305 >    static final class Values<K,V> extends CHMView<K,V>
3306 >        implements Collection<V> {
3307 >        Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3308          public final boolean contains(Object o) { return map.containsValue(o); }
3309 +        public final boolean remove(Object o) {
3310 +            if (o != null) {
3311 +                Iterator<V> it = new ValueIterator<K,V>(map);
3312 +                while (it.hasNext()) {
3313 +                    if (o.equals(it.next())) {
3314 +                        it.remove();
3315 +                        return true;
3316 +                    }
3317 +                }
3318 +            }
3319 +            return false;
3320 +        }
3321          public final Iterator<V> iterator() {
3322              return new ValueIterator<K,V>(map);
3323          }
3324 <    }
3325 <
3326 <    static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> {
3327 <        final ConcurrentHashMapV8<K, V> map;
3328 <        EntrySet(ConcurrentHashMapV8<K, V> map) { this.map = map; }
1516 <
1517 <        public final int size()                 { return map.size(); }
1518 <        public final boolean isEmpty()          { return map.isEmpty(); }
1519 <        public final void clear()               { map.clear(); }
1520 <        public final Iterator<Map.Entry<K,V>> iterator() {
1521 <            return new EntryIterator<K,V>(map);
3324 >        public final boolean add(V e) {
3325 >            throw new UnsupportedOperationException();
3326 >        }
3327 >        public final boolean addAll(Collection<? extends V> c) {
3328 >            throw new UnsupportedOperationException();
3329          }
3330  
3331 +    }
3332 +
3333 +    static final class EntrySet<K,V> extends CHMView<K,V>
3334 +        implements Set<Map.Entry<K,V>> {
3335 +        EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3336          public final boolean contains(Object o) {
3337              Object k, v, r; Map.Entry<?,?> e;
3338              return ((o instanceof Map.Entry) &&
# Line 1529 | Line 3341 | public class ConcurrentHashMapV8<K, V>
3341                      (v = e.getValue()) != null &&
3342                      (v == r || v.equals(r)));
3343          }
1532
3344          public final boolean remove(Object o) {
3345              Object k, v; Map.Entry<?,?> e;
3346              return ((o instanceof Map.Entry) &&
# Line 1537 | Line 3348 | public class ConcurrentHashMapV8<K, V>
3348                      (v = e.getValue()) != null &&
3349                      map.remove(k, v));
3350          }
3351 +        public final Iterator<Map.Entry<K,V>> iterator() {
3352 +            return new EntryIterator<K,V>(map);
3353 +        }
3354 +        public final boolean add(Entry<K,V> e) {
3355 +            throw new UnsupportedOperationException();
3356 +        }
3357 +        public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3358 +            throw new UnsupportedOperationException();
3359 +        }
3360 +        public boolean equals(Object o) {
3361 +            Set<?> c;
3362 +            return ((o instanceof Set) &&
3363 +                    ((c = (Set<?>)o) == this ||
3364 +                     (containsAll(c) && c.containsAll(this))));
3365 +        }
3366      }
3367  
3368      /* ---------------- Serialization Support -------------- */
# Line 1560 | Line 3386 | public class ConcurrentHashMapV8<K, V>
3386       * for each key-value mapping, followed by a null pair.
3387       * The key-value mappings are emitted in no particular order.
3388       */
3389 <    @SuppressWarnings("unchecked")
3390 <    private void writeObject(java.io.ObjectOutputStream s)
1565 <            throws java.io.IOException {
3389 >    @SuppressWarnings("unchecked") private void writeObject(java.io.ObjectOutputStream s)
3390 >        throws java.io.IOException {
3391          if (segments == null) { // for serialization compatibility
3392              segments = (Segment<K,V>[])
3393                  new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3394              for (int i = 0; i < segments.length; ++i)
3395 <                segments[i] = new Segment<K,V>(DEFAULT_LOAD_FACTOR);
3395 >                segments[i] = new Segment<K,V>(LOAD_FACTOR);
3396          }
3397          s.defaultWriteObject();
3398 <        InternalIterator it = new InternalIterator(table);
3399 <        while (it.next != null) {
3398 >        Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3399 >        Object v;
3400 >        while ((v = it.advance()) != null) {
3401              s.writeObject(it.nextKey);
3402 <            s.writeObject(it.nextVal);
1577 <            it.advance();
3402 >            s.writeObject(v);
3403          }
3404          s.writeObject(null);
3405          s.writeObject(null);
# Line 1585 | Line 3410 | public class ConcurrentHashMapV8<K, V>
3410       * Reconstitutes the instance from a stream (that is, deserializes it).
3411       * @param s the stream
3412       */
3413 <    @SuppressWarnings("unchecked")
3414 <    private void readObject(java.io.ObjectInputStream s)
1590 <            throws java.io.IOException, ClassNotFoundException {
3413 >    @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s)
3414 >        throws java.io.IOException, ClassNotFoundException {
3415          s.defaultReadObject();
3416          this.segments = null; // unneeded
3417 <        // initalize transient final fields
3417 >        // initialize transient final field
3418          UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
1595        UNSAFE.putFloatVolatile(this, loadFactorOffset, DEFAULT_LOAD_FACTOR);
1596        this.targetCapacity = DEFAULT_CAPACITY;
3419  
3420          // Create all nodes, then place in table once size is known
3421          long size = 0L;
# Line 1602 | Line 3424 | public class ConcurrentHashMapV8<K, V>
3424              K k = (K) s.readObject();
3425              V v = (V) s.readObject();
3426              if (k != null && v != null) {
3427 <                p = new Node(spread(k.hashCode()), k, v, p);
3427 >                int h = spread(k.hashCode());
3428 >                p = new Node(h, k, v, p);
3429                  ++size;
3430              }
3431              else
# Line 1610 | Line 3433 | public class ConcurrentHashMapV8<K, V>
3433          }
3434          if (p != null) {
3435              boolean init = false;
3436 <            if (resizing == 0 &&
3437 <                UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
3436 >            int n;
3437 >            if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3438 >                n = MAXIMUM_CAPACITY;
3439 >            else {
3440 >                int sz = (int)size;
3441 >                n = tableSizeFor(sz + (sz >>> 1) + 1);
3442 >            }
3443 >            int sc = sizeCtl;
3444 >            boolean collide = false;
3445 >            if (n > sc &&
3446 >                UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3447                  try {
3448                      if (table == null) {
3449                          init = true;
1618                        int n;
1619                        if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1620                            n = MAXIMUM_CAPACITY;
1621                        else {
1622                            int sz = (int)size;
1623                            n = tableSizeFor(sz + (sz >>> 1));
1624                        }
1625                        threshold = (n - (n >>> 2)) - THRESHOLD_OFFSET;
3450                          Node[] tab = new Node[n];
3451                          int mask = n - 1;
3452                          while (p != null) {
3453                              int j = p.hash & mask;
3454                              Node next = p.next;
3455 <                            p.next = tabAt(tab, j);
3455 >                            Node q = p.next = tabAt(tab, j);
3456                              setTabAt(tab, j, p);
3457 +                            if (!collide && q != null && q.hash == p.hash)
3458 +                                collide = true;
3459                              p = next;
3460                          }
3461                          table = tab;
3462                          counter.add(size);
3463 +                        sc = n - (n >>> 2);
3464                      }
3465                  } finally {
3466 <                    resizing = 0;
3466 >                    sizeCtl = sc;
3467 >                }
3468 >                if (collide) { // rescan and convert to TreeBins
3469 >                    Node[] tab = table;
3470 >                    for (int i = 0; i < tab.length; ++i) {
3471 >                        int c = 0;
3472 >                        for (Node e = tabAt(tab, i); e != null; e = e.next) {
3473 >                            if (++c > TREE_THRESHOLD &&
3474 >                                (e.key instanceof Comparable)) {
3475 >                                replaceWithTreeBin(tab, i, e.key);
3476 >                                break;
3477 >                            }
3478 >                        }
3479 >                    }
3480                  }
3481              }
3482              if (!init) { // Can only happen if unsafely published.
3483                  while (p != null) {
3484 <                    internalPut(p.key, p.val, true);
3484 >                    internalPut(p.key, p.val);
3485                      p = p.next;
3486                  }
3487              }
3488          }
3489      }
3490  
3491 +
3492 +    // -------------------------------------------------------
3493 +
3494 +    // Sams
3495 +    /** Interface describing a void action of one argument */
3496 +    public interface Action<A> { void apply(A a); }
3497 +    /** Interface describing a void action of two arguments */
3498 +    public interface BiAction<A,B> { void apply(A a, B b); }
3499 +    /** Interface describing a function of one argument */
3500 +    public interface Fun<A,T> { T apply(A a); }
3501 +    /** Interface describing a function of two arguments */
3502 +    public interface BiFun<A,B,T> { T apply(A a, B b); }
3503 +    /** Interface describing a function of no arguments */
3504 +    public interface Generator<T> { T apply(); }
3505 +    /** Interface describing a function mapping its argument to a double */
3506 +    public interface ObjectToDouble<A> { double apply(A a); }
3507 +    /** Interface describing a function mapping its argument to a long */
3508 +    public interface ObjectToLong<A> { long apply(A a); }
3509 +    /** Interface describing a function mapping its argument to an int */
3510 +    public interface ObjectToInt<A> {int apply(A a); }
3511 +    /** Interface describing a function mapping two arguments to a double */
3512 +    public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
3513 +    /** Interface describing a function mapping two arguments to a long */
3514 +    public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
3515 +    /** Interface describing a function mapping two arguments to an int */
3516 +    public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }
3517 +    /** Interface describing a function mapping a double to a double */
3518 +    public interface DoubleToDouble { double apply(double a); }
3519 +    /** Interface describing a function mapping a long to a long */
3520 +    public interface LongToLong { long apply(long a); }
3521 +    /** Interface describing a function mapping an int to an int */
3522 +    public interface IntToInt { int apply(int a); }
3523 +    /** Interface describing a function mapping two doubles to a double */
3524 +    public interface DoubleByDoubleToDouble { double apply(double a, double b); }
3525 +    /** Interface describing a function mapping two longs to a long */
3526 +    public interface LongByLongToLong { long apply(long a, long b); }
3527 +    /** Interface describing a function mapping two ints to an int */
3528 +    public interface IntByIntToInt { int apply(int a, int b); }
3529 +
3530 +
3531 +    // -------------------------------------------------------
3532 +
3533 +    /**
3534 +     * Returns an extended {@link Parallel} view of this map using the
3535 +     * given executor for bulk parallel operations.
3536 +     *
3537 +     * @param executor the executor
3538 +     * @return a parallel view
3539 +     */
3540 +    public Parallel parallel(ForkJoinPool executor)  {
3541 +        return new Parallel(executor);
3542 +    }
3543 +
3544 +    /**
3545 +     * An extended view of a ConcurrentHashMap supporting bulk
3546 +     * parallel operations. These operations are designed to be
3547 +     * safely, and often sensibly, applied even with maps that are
3548 +     * being concurrently updated by other threads; for example, when
3549 +     * computing a snapshot summary of the values in a shared
3550 +     * registry.  There are three kinds of operation, each with four
3551 +     * forms, accepting functions with Keys, Values, Entries, and
3552 +     * (Key, Value) arguments and/or return values. Because the
3553 +     * elements of a ConcurrentHashMap are not ordered in any
3554 +     * particular way, and may be processed in different orders in
3555 +     * different parallel executions, the correctness of supplied
3556 +     * functions should not depend on any ordering, or on any other
3557 +     * objects or values that may transiently change while computation
3558 +     * is in progress; and except for forEach actions, should ideally
3559 +     * be side-effect-free.
3560 +     *
3561 +     * <ul>
3562 +     * <li> forEach: Perform a given action on each element.
3563 +     * A variant form applies a given transformation on each element
3564 +     * before performing the action.</li>
3565 +     *
3566 +     * <li> search: Return the first available non-null result of
3567 +     * applying a given function on each element; skipping further
3568 +     * search when a result is found.</li>
3569 +     *
3570 +     * <li> reduce: Accumulate each element.  The supplied reduction
3571 +     * function cannot rely on ordering (more formally, it should be
3572 +     * both associative and commutative).  There are five variants:
3573 +     *
3574 +     * <ul>
3575 +     *
3576 +     * <li> Plain reductions. (There is not a form of this method for
3577 +     * (key, value) function arguments since there is no corresponding
3578 +     * return type.)</li>
3579 +     *
3580 +     * <li> Mapped reductions that accumulate the results of a given
3581 +     * function applied to each element.</li>
3582 +     *
3583 +     * <li> Reductions to scalar doubles, longs, and ints, using a
3584 +     * given basis value.</li>
3585 +     *
3586 +     * </li>
3587 +     * </ul>
3588 +     * </ul>
3589 +     *
3590 +     * <p>The concurrency properties of the bulk operations follow
3591 +     * from those of ConcurrentHashMap: Any non-null result returned
3592 +     * from {@code get(key)} and related access methods bears a
3593 +     * happens-before relation with the associated insertion or
3594 +     * update.  The result of any bulk operation reflects the
3595 +     * composition of these per-element relations (but is not
3596 +     * necessarily atomic with respect to the map as a whole unless it
3597 +     * is somehow known to be quiescent).  Conversely, because keys
3598 +     * and values in the map are never null, null serves as a reliable
3599 +     * atomic indicator of the current lack of any result.  To
3600 +     * maintain this property, null serves as an implicit basis for
3601 +     * all non-scalar reduction operations. For the double, long, and
3602 +     * int versions, the basis should be one that, when combined with
3603 +     * any other value, returns that other value (more formally, it
3604 +     * should be the identity element for the reduction). Most common
3605 +     * reductions have these properties; for example, computing a sum
3606 +     * with basis 0 or a minimum with basis MAX_VALUE.
3607 +     *
3608 +     * <p>Search and transformation functions provided as arguments
3609 +     * should similarly return null to indicate the lack of any result
3610 +     * (in which case it is not used). In the case of mapped
3611 +     * reductions, this also enables transformations to serve as
3612 +     * filters, returning null (or, in the case of primitive
3613 +     * specializations, the identity basis) if the element should not
3614 +     * be combined. You can create compound transformations and
3615 +     * filterings by composing them yourself under this "null means
3616 +     * there is nothing there now" rule before using them in search or
3617 +     * reduce operations.
3618 +     *
3619 +     * <p>Methods accepting and/or returning Entry arguments maintain
3620 +     * key-value associations. They may be useful for example when
3621 +     * finding the key for the greatest value. Note that "plain" Entry
3622 +     * arguments can be supplied using {@code new
3623 +     * AbstractMap.SimpleEntry(k,v)}.
3624 +     *
3625 +     * <p> Bulk operations may complete abruptly, throwing an
3626 +     * exception encountered in the application of a supplied
3627 +     * function. Bear in mind when handling such exceptions that other
3628 +     * concurrently executing functions could also have thrown
3629 +     * exceptions, or would have done so if the first exception had
3630 +     * not occurred.
3631 +     *
3632 +     * <p>Parallel speedups compared to sequential processing are
3633 +     * common but not guaranteed.  Operations involving brief
3634 +     * functions on small maps may execute more slowly than sequential
3635 +     * loops if the underlying work to parallelize the computation is
3636 +     * more expensive than the computation itself. Similarly,
3637 +     * parallelization may not lead to much actual parallelism if all
3638 +     * processors are busy performing unrelated tasks.
3639 +     *
3640 +     * <p> All arguments to all task methods must be non-null.
3641 +     *
3642 +     * <p><em>jsr166e note: During transition, this class
3643 +     * uses nested functional interfaces with different names but the
3644 +     * same forms as those expected for JDK8.<em>
3645 +     */
3646 +    public class Parallel {
3647 +        final ForkJoinPool fjp;
3648 +
3649 +        /**
3650 +         * Returns an extended view of this map using the given
3651 +         * executor for bulk parallel operations.
3652 +         *
3653 +         * @param executor the executor
3654 +         */
3655 +        public Parallel(ForkJoinPool executor)  {
3656 +            this.fjp = executor;
3657 +        }
3658 +
3659 +        /**
3660 +         * Performs the given action for each (key, value).
3661 +         *
3662 +         * @param action the action
3663 +         */
3664 +        public void forEach(BiAction<K,V> action) {
3665 +            fjp.invoke(ForkJoinTasks.forEach
3666 +                       (ConcurrentHashMapV8.this, action));
3667 +        }
3668 +
3669 +        /**
3670 +         * Performs the given action for each non-null transformation
3671 +         * of each (key, value).
3672 +         *
3673 +         * @param transformer a function returning the transformation
3674 +         * for an element, or null of there is no transformation (in
3675 +         * which case the action is not applied).
3676 +         * @param action the action
3677 +         */
3678 +        public <U> void forEach(BiFun<? super K, ? super V, ? extends U> transformer,
3679 +                                Action<U> action) {
3680 +            fjp.invoke(ForkJoinTasks.forEach
3681 +                       (ConcurrentHashMapV8.this, transformer, action));
3682 +        }
3683 +
3684 +        /**
3685 +         * Returns a non-null result from applying the given search
3686 +         * function on each (key, value), or null if none.  Upon
3687 +         * success, further element processing is suppressed and the
3688 +         * results of any other parallel invocations of the search
3689 +         * function are ignored.
3690 +         *
3691 +         * @param searchFunction a function returning a non-null
3692 +         * result on success, else null
3693 +         * @return a non-null result from applying the given search
3694 +         * function on each (key, value), or null if none
3695 +         */
3696 +        public <U> U search(BiFun<? super K, ? super V, ? extends U> searchFunction) {
3697 +            return fjp.invoke(ForkJoinTasks.search
3698 +                              (ConcurrentHashMapV8.this, searchFunction));
3699 +        }
3700 +
3701 +        /**
3702 +         * Returns the result of accumulating the given transformation
3703 +         * of all (key, value) pairs using the given reducer to
3704 +         * combine values, or null if none.
3705 +         *
3706 +         * @param transformer a function returning the transformation
3707 +         * for an element, or null of there is no transformation (in
3708 +         * which case it is not combined).
3709 +         * @param reducer a commutative associative combining function
3710 +         * @return the result of accumulating the given transformation
3711 +         * of all (key, value) pairs
3712 +         */
3713 +        public <U> U reduce(BiFun<? super K, ? super V, ? extends U> transformer,
3714 +                            BiFun<? super U, ? super U, ? extends U> reducer) {
3715 +            return fjp.invoke(ForkJoinTasks.reduce
3716 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3717 +        }
3718 +
3719 +        /**
3720 +         * Returns the result of accumulating the given transformation
3721 +         * of all (key, value) pairs using the given reducer to
3722 +         * combine values, and the given basis as an identity value.
3723 +         *
3724 +         * @param transformer a function returning the transformation
3725 +         * for an element
3726 +         * @param basis the identity (initial default value) for the reduction
3727 +         * @param reducer a commutative associative combining function
3728 +         * @return the result of accumulating the given transformation
3729 +         * of all (key, value) pairs
3730 +         */
3731 +        public double reduceToDouble(ObjectByObjectToDouble<? super K, ? super V> transformer,
3732 +                                     double basis,
3733 +                                     DoubleByDoubleToDouble reducer) {
3734 +            return fjp.invoke(ForkJoinTasks.reduceToDouble
3735 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3736 +        }
3737 +
3738 +        /**
3739 +         * Returns the result of accumulating the given transformation
3740 +         * of all (key, value) pairs using the given reducer to
3741 +         * combine values, and the given basis as an identity value.
3742 +         *
3743 +         * @param transformer a function returning the transformation
3744 +         * for an element
3745 +         * @param basis the identity (initial default value) for the reduction
3746 +         * @param reducer a commutative associative combining function
3747 +         * @return the result of accumulating the given transformation
3748 +         * of all (key, value) pairs
3749 +         */
3750 +        public long reduceToLong(ObjectByObjectToLong<? super K, ? super V> transformer,
3751 +                                 long basis,
3752 +                                 LongByLongToLong reducer) {
3753 +            return fjp.invoke(ForkJoinTasks.reduceToLong
3754 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3755 +        }
3756 +
3757 +        /**
3758 +         * Returns the result of accumulating the given transformation
3759 +         * of all (key, value) pairs using the given reducer to
3760 +         * combine values, and the given basis as an identity value.
3761 +         *
3762 +         * @param transformer a function returning the transformation
3763 +         * for an element
3764 +         * @param basis the identity (initial default value) for the reduction
3765 +         * @param reducer a commutative associative combining function
3766 +         * @return the result of accumulating the given transformation
3767 +         * of all (key, value) pairs
3768 +         */
3769 +        public int reduceToInt(ObjectByObjectToInt<? super K, ? super V> transformer,
3770 +                               int basis,
3771 +                               IntByIntToInt reducer) {
3772 +            return fjp.invoke(ForkJoinTasks.reduceToInt
3773 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3774 +        }
3775 +
3776 +        /**
3777 +         * Performs the given action for each key.
3778 +         *
3779 +         * @param action the action
3780 +         */
3781 +        public void forEachKey(Action<K> action) {
3782 +            fjp.invoke(ForkJoinTasks.forEachKey
3783 +                       (ConcurrentHashMapV8.this, action));
3784 +        }
3785 +
3786 +        /**
3787 +         * Performs the given action for each non-null transformation
3788 +         * of each key.
3789 +         *
3790 +         * @param transformer a function returning the transformation
3791 +         * for an element, or null of there is no transformation (in
3792 +         * which case the action is not applied).
3793 +         * @param action the action
3794 +         */
3795 +        public <U> void forEachKey(Fun<? super K, ? extends U> transformer,
3796 +                                   Action<U> action) {
3797 +            fjp.invoke(ForkJoinTasks.forEachKey
3798 +                       (ConcurrentHashMapV8.this, transformer, action));
3799 +        }
3800 +
3801 +        /**
3802 +         * Returns a non-null result from applying the given search
3803 +         * function on each key, or null if none. Upon success,
3804 +         * further element processing is suppressed and the results of
3805 +         * any other parallel invocations of the search function are
3806 +         * ignored.
3807 +         *
3808 +         * @param searchFunction a function returning a non-null
3809 +         * result on success, else null
3810 +         * @return a non-null result from applying the given search
3811 +         * function on each key, or null if none
3812 +         */
3813 +        public <U> U searchKeys(Fun<? super K, ? extends U> searchFunction) {
3814 +            return fjp.invoke(ForkJoinTasks.searchKeys
3815 +                              (ConcurrentHashMapV8.this, searchFunction));
3816 +        }
3817 +
3818 +        /**
3819 +         * Returns the result of accumulating all keys using the given
3820 +         * reducer to combine values, or null if none.
3821 +         *
3822 +         * @param reducer a commutative associative combining function
3823 +         * @return the result of accumulating all keys using the given
3824 +         * reducer to combine values, or null if none
3825 +         */
3826 +        public K reduceKeys(BiFun<? super K, ? super K, ? extends K> reducer) {
3827 +            return fjp.invoke(ForkJoinTasks.reduceKeys
3828 +                              (ConcurrentHashMapV8.this, reducer));
3829 +        }
3830 +
3831 +        /**
3832 +         * Returns the result of accumulating the given transformation
3833 +         * of all keys using the given reducer to combine values, or
3834 +         * null if none.
3835 +         *
3836 +         * @param transformer a function returning the transformation
3837 +         * for an element, or null of there is no transformation (in
3838 +         * which case it is not combined).
3839 +         * @param reducer a commutative associative combining function
3840 +         * @return the result of accumulating the given transformation
3841 +         * of all keys
3842 +         */
3843 +        public <U> U reduceKeys(Fun<? super K, ? extends U> transformer,
3844 +                                BiFun<? super U, ? super U, ? extends U> reducer) {
3845 +            return fjp.invoke(ForkJoinTasks.reduceKeys
3846 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3847 +        }
3848 +
3849 +        /**
3850 +         * Returns the result of accumulating the given transformation
3851 +         * of all keys using the given reducer to combine values, and
3852 +         * the given basis as an identity value.
3853 +         *
3854 +         * @param transformer a function returning the transformation
3855 +         * for an element
3856 +         * @param basis the identity (initial default value) for the reduction
3857 +         * @param reducer a commutative associative combining function
3858 +         * @return  the result of accumulating the given transformation
3859 +         * of all keys
3860 +         */
3861 +        public double reduceKeysToDouble(ObjectToDouble<? super K> transformer,
3862 +                                         double basis,
3863 +                                         DoubleByDoubleToDouble reducer) {
3864 +            return fjp.invoke(ForkJoinTasks.reduceKeysToDouble
3865 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3866 +        }
3867 +
3868 +        /**
3869 +         * Returns the result of accumulating the given transformation
3870 +         * of all keys using the given reducer to combine values, and
3871 +         * the given basis as an identity value.
3872 +         *
3873 +         * @param transformer a function returning the transformation
3874 +         * for an element
3875 +         * @param basis the identity (initial default value) for the reduction
3876 +         * @param reducer a commutative associative combining function
3877 +         * @return the result of accumulating the given transformation
3878 +         * of all keys
3879 +         */
3880 +        public long reduceKeysToLong(ObjectToLong<? super K> transformer,
3881 +                                     long basis,
3882 +                                     LongByLongToLong reducer) {
3883 +            return fjp.invoke(ForkJoinTasks.reduceKeysToLong
3884 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3885 +        }
3886 +
3887 +        /**
3888 +         * Returns the result of accumulating the given transformation
3889 +         * of all keys using the given reducer to combine values, and
3890 +         * the given basis as an identity value.
3891 +         *
3892 +         * @param transformer a function returning the transformation
3893 +         * for an element
3894 +         * @param basis the identity (initial default value) for the reduction
3895 +         * @param reducer a commutative associative combining function
3896 +         * @return the result of accumulating the given transformation
3897 +         * of all keys
3898 +         */
3899 +        public int reduceKeysToInt(ObjectToInt<? super K> transformer,
3900 +                                   int basis,
3901 +                                   IntByIntToInt reducer) {
3902 +            return fjp.invoke(ForkJoinTasks.reduceKeysToInt
3903 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3904 +        }
3905 +
3906 +        /**
3907 +         * Performs the given action for each value.
3908 +         *
3909 +         * @param action the action
3910 +         */
3911 +        public void forEachValue(Action<V> action) {
3912 +            fjp.invoke(ForkJoinTasks.forEachValue
3913 +                       (ConcurrentHashMapV8.this, action));
3914 +        }
3915 +
3916 +        /**
3917 +         * Performs the given action for each non-null transformation
3918 +         * of each value.
3919 +         *
3920 +         * @param transformer a function returning the transformation
3921 +         * for an element, or null of there is no transformation (in
3922 +         * which case the action is not applied).
3923 +         */
3924 +        public <U> void forEachValue(Fun<? super V, ? extends U> transformer,
3925 +                                     Action<U> action) {
3926 +            fjp.invoke(ForkJoinTasks.forEachValue
3927 +                       (ConcurrentHashMapV8.this, transformer, action));
3928 +        }
3929 +
3930 +        /**
3931 +         * Returns a non-null result from applying the given search
3932 +         * function on each value, or null if none.  Upon success,
3933 +         * further element processing is suppressed and the results of
3934 +         * any other parallel invocations of the search function are
3935 +         * ignored.
3936 +         *
3937 +         * @param searchFunction a function returning a non-null
3938 +         * result on success, else null
3939 +         * @return a non-null result from applying the given search
3940 +         * function on each value, or null if none
3941 +         *
3942 +         */
3943 +        public <U> U searchValues(Fun<? super V, ? extends U> searchFunction) {
3944 +            return fjp.invoke(ForkJoinTasks.searchValues
3945 +                              (ConcurrentHashMapV8.this, searchFunction));
3946 +        }
3947 +
3948 +        /**
3949 +         * Returns the result of accumulating all values using the
3950 +         * given reducer to combine values, or null if none.
3951 +         *
3952 +         * @param reducer a commutative associative combining function
3953 +         * @return  the result of accumulating all values
3954 +         */
3955 +        public V reduceValues(BiFun<? super V, ? super V, ? extends V> reducer) {
3956 +            return fjp.invoke(ForkJoinTasks.reduceValues
3957 +                              (ConcurrentHashMapV8.this, reducer));
3958 +        }
3959 +
3960 +        /**
3961 +         * Returns the result of accumulating the given transformation
3962 +         * of all values using the given reducer to combine values, or
3963 +         * null if none.
3964 +         *
3965 +         * @param transformer a function returning the transformation
3966 +         * for an element, or null of there is no transformation (in
3967 +         * which case it is not combined).
3968 +         * @param reducer a commutative associative combining function
3969 +         * @return the result of accumulating the given transformation
3970 +         * of all values
3971 +         */
3972 +        public <U> U reduceValues(Fun<? super V, ? extends U> transformer,
3973 +                                  BiFun<? super U, ? super U, ? extends U> reducer) {
3974 +            return fjp.invoke(ForkJoinTasks.reduceValues
3975 +                              (ConcurrentHashMapV8.this, transformer, reducer));
3976 +        }
3977 +
3978 +        /**
3979 +         * Returns the result of accumulating the given transformation
3980 +         * of all values using the given reducer to combine values,
3981 +         * and the given basis as an identity value.
3982 +         *
3983 +         * @param transformer a function returning the transformation
3984 +         * for an element
3985 +         * @param basis the identity (initial default value) for the reduction
3986 +         * @param reducer a commutative associative combining function
3987 +         * @return the result of accumulating the given transformation
3988 +         * of all values
3989 +         */
3990 +        public double reduceValuesToDouble(ObjectToDouble<? super V> transformer,
3991 +                                           double basis,
3992 +                                           DoubleByDoubleToDouble reducer) {
3993 +            return fjp.invoke(ForkJoinTasks.reduceValuesToDouble
3994 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
3995 +        }
3996 +
3997 +        /**
3998 +         * Returns the result of accumulating the given transformation
3999 +         * of all values using the given reducer to combine values,
4000 +         * and the given basis as an identity value.
4001 +         *
4002 +         * @param transformer a function returning the transformation
4003 +         * for an element
4004 +         * @param basis the identity (initial default value) for the reduction
4005 +         * @param reducer a commutative associative combining function
4006 +         * @return the result of accumulating the given transformation
4007 +         * of all values
4008 +         */
4009 +        public long reduceValuesToLong(ObjectToLong<? super V> transformer,
4010 +                                       long basis,
4011 +                                       LongByLongToLong reducer) {
4012 +            return fjp.invoke(ForkJoinTasks.reduceValuesToLong
4013 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4014 +        }
4015 +
4016 +        /**
4017 +         * Returns the result of accumulating the given transformation
4018 +         * of all values using the given reducer to combine values,
4019 +         * and the given basis as an identity value.
4020 +         *
4021 +         * @param transformer a function returning the transformation
4022 +         * for an element
4023 +         * @param basis the identity (initial default value) for the reduction
4024 +         * @param reducer a commutative associative combining function
4025 +         * @return the result of accumulating the given transformation
4026 +         * of all values
4027 +         */
4028 +        public int reduceValuesToInt(ObjectToInt<? super V> transformer,
4029 +                                     int basis,
4030 +                                     IntByIntToInt reducer) {
4031 +            return fjp.invoke(ForkJoinTasks.reduceValuesToInt
4032 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4033 +        }
4034 +
4035 +        /**
4036 +         * Performs the given action for each entry.
4037 +         *
4038 +         * @param action the action
4039 +         */
4040 +        public void forEachEntry(Action<Map.Entry<K,V>> action) {
4041 +            fjp.invoke(ForkJoinTasks.forEachEntry
4042 +                       (ConcurrentHashMapV8.this, action));
4043 +        }
4044 +
4045 +        /**
4046 +         * Performs the given action for each non-null transformation
4047 +         * of each entry.
4048 +         *
4049 +         * @param transformer a function returning the transformation
4050 +         * for an element, or null of there is no transformation (in
4051 +         * which case the action is not applied).
4052 +         * @param action the action
4053 +         */
4054 +        public <U> void forEachEntry(Fun<Map.Entry<K,V>, ? extends U> transformer,
4055 +                                     Action<U> action) {
4056 +            fjp.invoke(ForkJoinTasks.forEachEntry
4057 +                       (ConcurrentHashMapV8.this, transformer, action));
4058 +        }
4059 +
4060 +        /**
4061 +         * Returns a non-null result from applying the given search
4062 +         * function on each entry, or null if none.  Upon success,
4063 +         * further element processing is suppressed and the results of
4064 +         * any other parallel invocations of the search function are
4065 +         * ignored.
4066 +         *
4067 +         * @param searchFunction a function returning a non-null
4068 +         * result on success, else null
4069 +         * @return a non-null result from applying the given search
4070 +         * function on each entry, or null if none
4071 +         */
4072 +        public <U> U searchEntries(Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4073 +            return fjp.invoke(ForkJoinTasks.searchEntries
4074 +                              (ConcurrentHashMapV8.this, searchFunction));
4075 +        }
4076 +
4077 +        /**
4078 +         * Returns the result of accumulating all entries using the
4079 +         * given reducer to combine values, or null if none.
4080 +         *
4081 +         * @param reducer a commutative associative combining function
4082 +         * @return the result of accumulating all entries
4083 +         */
4084 +        public Map.Entry<K,V> reduceEntries(BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4085 +            return fjp.invoke(ForkJoinTasks.reduceEntries
4086 +                              (ConcurrentHashMapV8.this, reducer));
4087 +        }
4088 +
4089 +        /**
4090 +         * Returns the result of accumulating the given transformation
4091 +         * of all entries using the given reducer to combine values,
4092 +         * or null if none.
4093 +         *
4094 +         * @param transformer a function returning the transformation
4095 +         * for an element, or null of there is no transformation (in
4096 +         * which case it is not combined).
4097 +         * @param reducer a commutative associative combining function
4098 +         * @return the result of accumulating the given transformation
4099 +         * of all entries
4100 +         */
4101 +        public <U> U reduceEntries(Fun<Map.Entry<K,V>, ? extends U> transformer,
4102 +                                   BiFun<? super U, ? super U, ? extends U> reducer) {
4103 +            return fjp.invoke(ForkJoinTasks.reduceEntries
4104 +                              (ConcurrentHashMapV8.this, transformer, reducer));
4105 +        }
4106 +
4107 +        /**
4108 +         * Returns the result of accumulating the given transformation
4109 +         * of all entries using the given reducer to combine values,
4110 +         * and the given basis as an identity value.
4111 +         *
4112 +         * @param transformer a function returning the transformation
4113 +         * for an element
4114 +         * @param basis the identity (initial default value) for the reduction
4115 +         * @param reducer a commutative associative combining function
4116 +         * @return the result of accumulating the given transformation
4117 +         * of all entries
4118 +         */
4119 +        public double reduceEntriesToDouble(ObjectToDouble<Map.Entry<K,V>> transformer,
4120 +                                            double basis,
4121 +                                            DoubleByDoubleToDouble reducer) {
4122 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToDouble
4123 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4124 +        }
4125 +
4126 +        /**
4127 +         * Returns the result of accumulating the given transformation
4128 +         * of all entries using the given reducer to combine values,
4129 +         * and the given basis as an identity value.
4130 +         *
4131 +         * @param transformer a function returning the transformation
4132 +         * for an element
4133 +         * @param basis the identity (initial default value) for the reduction
4134 +         * @param reducer a commutative associative combining function
4135 +         * @return  the result of accumulating the given transformation
4136 +         * of all entries
4137 +         */
4138 +        public long reduceEntriesToLong(ObjectToLong<Map.Entry<K,V>> transformer,
4139 +                                        long basis,
4140 +                                        LongByLongToLong reducer) {
4141 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToLong
4142 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4143 +        }
4144 +
4145 +        /**
4146 +         * Returns the result of accumulating the given transformation
4147 +         * of all entries using the given reducer to combine values,
4148 +         * and the given basis as an identity value.
4149 +         *
4150 +         * @param transformer a function returning the transformation
4151 +         * for an element
4152 +         * @param basis the identity (initial default value) for the reduction
4153 +         * @param reducer a commutative associative combining function
4154 +         * @return the result of accumulating the given transformation
4155 +         * of all entries
4156 +         */
4157 +        public int reduceEntriesToInt(ObjectToInt<Map.Entry<K,V>> transformer,
4158 +                                      int basis,
4159 +                                      IntByIntToInt reducer) {
4160 +            return fjp.invoke(ForkJoinTasks.reduceEntriesToInt
4161 +                              (ConcurrentHashMapV8.this, transformer, basis, reducer));
4162 +        }
4163 +    }
4164 +
4165 +    // ---------------------------------------------------------------------
4166 +
4167 +    /**
4168 +     * Predefined tasks for performing bulk parallel operations on
4169 +     * ConcurrentHashMaps. These tasks follow the forms and rules used
4170 +     * in class {@link Parallel}. Each method has the same name, but
4171 +     * returns a task rather than invoking it. These methods may be
4172 +     * useful in custom applications such as submitting a task without
4173 +     * waiting for completion, or combining with other tasks.
4174 +     */
4175 +    public static class ForkJoinTasks {
4176 +        private ForkJoinTasks() {}
4177 +
4178 +        /**
4179 +         * Returns a task that when invoked, performs the given
4180 +         * action for each (key, value)
4181 +         *
4182 +         * @param map the map
4183 +         * @param action the action
4184 +         * @return the task
4185 +         */
4186 +        public static <K,V> ForkJoinTask<Void> forEach
4187 +            (ConcurrentHashMapV8<K,V> map,
4188 +             BiAction<K,V> action) {
4189 +            if (action == null) throw new NullPointerException();
4190 +            return new ForEachMappingTask<K,V>(map, null, -1, action);
4191 +        }
4192 +
4193 +        /**
4194 +         * Returns a task that when invoked, performs the given
4195 +         * action for each non-null transformation of each (key, value)
4196 +         *
4197 +         * @param map the map
4198 +         * @param transformer a function returning the transformation
4199 +         * for an element, or null of there is no transformation (in
4200 +         * which case the action is not applied).
4201 +         * @param action the action
4202 +         * @return the task
4203 +         */
4204 +        public static <K,V,U> ForkJoinTask<Void> forEach
4205 +            (ConcurrentHashMapV8<K,V> map,
4206 +             BiFun<? super K, ? super V, ? extends U> transformer,
4207 +             Action<U> action) {
4208 +            if (transformer == null || action == null)
4209 +                throw new NullPointerException();
4210 +            return new ForEachTransformedMappingTask<K,V,U>
4211 +                (map, null, -1, transformer, action);
4212 +        }
4213 +
4214 +        /**
4215 +         * Returns a task that when invoked, returns a non-null result
4216 +         * from applying the given search function on each (key,
4217 +         * value), or null if none. Upon success, further element
4218 +         * processing is suppressed and the results of any other
4219 +         * parallel invocations of the search function are ignored.
4220 +         *
4221 +         * @param map the map
4222 +         * @param searchFunction a function returning a non-null
4223 +         * result on success, else null
4224 +         * @return the task
4225 +         */
4226 +        public static <K,V,U> ForkJoinTask<U> search
4227 +            (ConcurrentHashMapV8<K,V> map,
4228 +             BiFun<? super K, ? super V, ? extends U> searchFunction) {
4229 +            if (searchFunction == null) throw new NullPointerException();
4230 +            return new SearchMappingsTask<K,V,U>
4231 +                (map, null, -1, searchFunction,
4232 +                 new AtomicReference<U>());
4233 +        }
4234 +
4235 +        /**
4236 +         * Returns a task that when invoked, returns the result of
4237 +         * accumulating the given transformation of all (key, value) pairs
4238 +         * using the given reducer to combine values, or null if none.
4239 +         *
4240 +         * @param map the map
4241 +         * @param transformer a function returning the transformation
4242 +         * for an element, or null of there is no transformation (in
4243 +         * which case it is not combined).
4244 +         * @param reducer a commutative associative combining function
4245 +         * @return the task
4246 +         */
4247 +        public static <K,V,U> ForkJoinTask<U> reduce
4248 +            (ConcurrentHashMapV8<K,V> map,
4249 +             BiFun<? super K, ? super V, ? extends U> transformer,
4250 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4251 +            if (transformer == null || reducer == null)
4252 +                throw new NullPointerException();
4253 +            return new MapReduceMappingsTask<K,V,U>
4254 +                (map, null, -1, null, transformer, reducer);
4255 +        }
4256 +
4257 +        /**
4258 +         * Returns a task that when invoked, returns the result of
4259 +         * accumulating the given transformation of all (key, value) pairs
4260 +         * using the given reducer to combine values, and the given
4261 +         * basis as an identity value.
4262 +         *
4263 +         * @param map the map
4264 +         * @param transformer a function returning the transformation
4265 +         * for an element
4266 +         * @param basis the identity (initial default value) for the reduction
4267 +         * @param reducer a commutative associative combining function
4268 +         * @return the task
4269 +         */
4270 +        public static <K,V> ForkJoinTask<Double> reduceToDouble
4271 +            (ConcurrentHashMapV8<K,V> map,
4272 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
4273 +             double basis,
4274 +             DoubleByDoubleToDouble reducer) {
4275 +            if (transformer == null || reducer == null)
4276 +                throw new NullPointerException();
4277 +            return new MapReduceMappingsToDoubleTask<K,V>
4278 +                (map, null, -1, null, transformer, basis, reducer);
4279 +        }
4280 +
4281 +        /**
4282 +         * Returns a task that when invoked, returns the result of
4283 +         * accumulating the given transformation of all (key, value) pairs
4284 +         * using the given reducer to combine values, and the given
4285 +         * basis as an identity value.
4286 +         *
4287 +         * @param map the map
4288 +         * @param transformer a function returning the transformation
4289 +         * for an element
4290 +         * @param basis the identity (initial default value) for the reduction
4291 +         * @param reducer a commutative associative combining function
4292 +         * @return the task
4293 +         */
4294 +        public static <K,V> ForkJoinTask<Long> reduceToLong
4295 +            (ConcurrentHashMapV8<K,V> map,
4296 +             ObjectByObjectToLong<? super K, ? super V> transformer,
4297 +             long basis,
4298 +             LongByLongToLong reducer) {
4299 +            if (transformer == null || reducer == null)
4300 +                throw new NullPointerException();
4301 +            return new MapReduceMappingsToLongTask<K,V>
4302 +                (map, null, -1, null, transformer, basis, reducer);
4303 +        }
4304 +
4305 +        /**
4306 +         * Returns a task that when invoked, returns the result of
4307 +         * accumulating the given transformation of all (key, value) pairs
4308 +         * using the given reducer to combine values, and the given
4309 +         * basis as an identity value.
4310 +         *
4311 +         * @param transformer a function returning the transformation
4312 +         * for an element
4313 +         * @param basis the identity (initial default value) for the reduction
4314 +         * @param reducer a commutative associative combining function
4315 +         * @return the task
4316 +         */
4317 +        public static <K,V> ForkJoinTask<Integer> reduceToInt
4318 +            (ConcurrentHashMapV8<K,V> map,
4319 +             ObjectByObjectToInt<? super K, ? super V> transformer,
4320 +             int basis,
4321 +             IntByIntToInt reducer) {
4322 +            if (transformer == null || reducer == null)
4323 +                throw new NullPointerException();
4324 +            return new MapReduceMappingsToIntTask<K,V>
4325 +                (map, null, -1, null, transformer, basis, reducer);
4326 +        }
4327 +
4328 +        /**
4329 +         * Returns a task that when invoked, performs the given action
4330 +         * for each key.
4331 +         *
4332 +         * @param map the map
4333 +         * @param action the action
4334 +         * @return the task
4335 +         */
4336 +        public static <K,V> ForkJoinTask<Void> forEachKey
4337 +            (ConcurrentHashMapV8<K,V> map,
4338 +             Action<K> action) {
4339 +            if (action == null) throw new NullPointerException();
4340 +            return new ForEachKeyTask<K,V>(map, null, -1, action);
4341 +        }
4342 +
4343 +        /**
4344 +         * Returns a task that when invoked, performs the given action
4345 +         * for each non-null transformation of each key.
4346 +         *
4347 +         * @param map the map
4348 +         * @param transformer a function returning the transformation
4349 +         * for an element, or null of there is no transformation (in
4350 +         * which case the action is not applied).
4351 +         * @param action the action
4352 +         * @return the task
4353 +         */
4354 +        public static <K,V,U> ForkJoinTask<Void> forEachKey
4355 +            (ConcurrentHashMapV8<K,V> map,
4356 +             Fun<? super K, ? extends U> transformer,
4357 +             Action<U> action) {
4358 +            if (transformer == null || action == null)
4359 +                throw new NullPointerException();
4360 +            return new ForEachTransformedKeyTask<K,V,U>
4361 +                (map, null, -1, transformer, action);
4362 +        }
4363 +
4364 +        /**
4365 +         * Returns a task that when invoked, returns a non-null result
4366 +         * from applying the given search function on each key, or
4367 +         * null if none.  Upon success, further element processing is
4368 +         * suppressed and the results of any other parallel
4369 +         * invocations of the search function are ignored.
4370 +         *
4371 +         * @param map the map
4372 +         * @param searchFunction a function returning a non-null
4373 +         * result on success, else null
4374 +         * @return the task
4375 +         */
4376 +        public static <K,V,U> ForkJoinTask<U> searchKeys
4377 +            (ConcurrentHashMapV8<K,V> map,
4378 +             Fun<? super K, ? extends U> searchFunction) {
4379 +            if (searchFunction == null) throw new NullPointerException();
4380 +            return new SearchKeysTask<K,V,U>
4381 +                (map, null, -1, searchFunction,
4382 +                 new AtomicReference<U>());
4383 +        }
4384 +
4385 +        /**
4386 +         * Returns a task that when invoked, returns the result of
4387 +         * accumulating all keys using the given reducer to combine
4388 +         * values, or null if none.
4389 +         *
4390 +         * @param map the map
4391 +         * @param reducer a commutative associative combining function
4392 +         * @return the task
4393 +         */
4394 +        public static <K,V> ForkJoinTask<K> reduceKeys
4395 +            (ConcurrentHashMapV8<K,V> map,
4396 +             BiFun<? super K, ? super K, ? extends K> reducer) {
4397 +            if (reducer == null) throw new NullPointerException();
4398 +            return new ReduceKeysTask<K,V>
4399 +                (map, null, -1, null, reducer);
4400 +        }
4401 +
4402 +        /**
4403 +         * Returns a task that when invoked, returns the result of
4404 +         * accumulating the given transformation of all keys using the given
4405 +         * reducer to combine values, or null if none.
4406 +         *
4407 +         * @param map the map
4408 +         * @param transformer a function returning the transformation
4409 +         * for an element, or null of there is no transformation (in
4410 +         * which case it is not combined).
4411 +         * @param reducer a commutative associative combining function
4412 +         * @return the task
4413 +         */
4414 +        public static <K,V,U> ForkJoinTask<U> reduceKeys
4415 +            (ConcurrentHashMapV8<K,V> map,
4416 +             Fun<? super K, ? extends U> transformer,
4417 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4418 +            if (transformer == null || reducer == null)
4419 +                throw new NullPointerException();
4420 +            return new MapReduceKeysTask<K,V,U>
4421 +                (map, null, -1, null, transformer, reducer);
4422 +        }
4423 +
4424 +        /**
4425 +         * Returns a task that when invoked, returns the result of
4426 +         * accumulating the given transformation of all keys using the given
4427 +         * reducer to combine values, and the given basis as an
4428 +         * identity value.
4429 +         *
4430 +         * @param map the map
4431 +         * @param transformer a function returning the transformation
4432 +         * for an element
4433 +         * @param basis the identity (initial default value) for the reduction
4434 +         * @param reducer a commutative associative combining function
4435 +         * @return the task
4436 +         */
4437 +        public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
4438 +            (ConcurrentHashMapV8<K,V> map,
4439 +             ObjectToDouble<? super K> transformer,
4440 +             double basis,
4441 +             DoubleByDoubleToDouble reducer) {
4442 +            if (transformer == null || reducer == null)
4443 +                throw new NullPointerException();
4444 +            return new MapReduceKeysToDoubleTask<K,V>
4445 +                (map, null, -1, null, transformer, basis, reducer);
4446 +        }
4447 +
4448 +        /**
4449 +         * Returns a task that when invoked, returns the result of
4450 +         * accumulating the given transformation of all keys using the given
4451 +         * reducer to combine values, and the given basis as an
4452 +         * identity value.
4453 +         *
4454 +         * @param map the map
4455 +         * @param transformer a function returning the transformation
4456 +         * for an element
4457 +         * @param basis the identity (initial default value) for the reduction
4458 +         * @param reducer a commutative associative combining function
4459 +         * @return the task
4460 +         */
4461 +        public static <K,V> ForkJoinTask<Long> reduceKeysToLong
4462 +            (ConcurrentHashMapV8<K,V> map,
4463 +             ObjectToLong<? super K> transformer,
4464 +             long basis,
4465 +             LongByLongToLong reducer) {
4466 +            if (transformer == null || reducer == null)
4467 +                throw new NullPointerException();
4468 +            return new MapReduceKeysToLongTask<K,V>
4469 +                (map, null, -1, null, transformer, basis, reducer);
4470 +        }
4471 +
4472 +        /**
4473 +         * Returns a task that when invoked, returns the result of
4474 +         * accumulating the given transformation of all keys using the given
4475 +         * reducer to combine values, and the given basis as an
4476 +         * identity value.
4477 +         *
4478 +         * @param map the map
4479 +         * @param transformer a function returning the transformation
4480 +         * for an element
4481 +         * @param basis the identity (initial default value) for the reduction
4482 +         * @param reducer a commutative associative combining function
4483 +         * @return the task
4484 +         */
4485 +        public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
4486 +            (ConcurrentHashMapV8<K,V> map,
4487 +             ObjectToInt<? super K> transformer,
4488 +             int basis,
4489 +             IntByIntToInt reducer) {
4490 +            if (transformer == null || reducer == null)
4491 +                throw new NullPointerException();
4492 +            return new MapReduceKeysToIntTask<K,V>
4493 +                (map, null, -1, null, transformer, basis, reducer);
4494 +        }
4495 +
4496 +        /**
4497 +         * Returns a task that when invoked, performs the given action
4498 +         * for each value.
4499 +         *
4500 +         * @param map the map
4501 +         * @param action the action
4502 +         */
4503 +        public static <K,V> ForkJoinTask<Void> forEachValue
4504 +            (ConcurrentHashMapV8<K,V> map,
4505 +             Action<V> action) {
4506 +            if (action == null) throw new NullPointerException();
4507 +            return new ForEachValueTask<K,V>(map, null, -1, action);
4508 +        }
4509 +
4510 +        /**
4511 +         * Returns a task that when invoked, performs the given action
4512 +         * for each non-null transformation of each value.
4513 +         *
4514 +         * @param map the map
4515 +         * @param transformer a function returning the transformation
4516 +         * for an element, or null of there is no transformation (in
4517 +         * which case the action is not applied).
4518 +         * @param action the action
4519 +         */
4520 +        public static <K,V,U> ForkJoinTask<Void> forEachValue
4521 +            (ConcurrentHashMapV8<K,V> map,
4522 +             Fun<? super V, ? extends U> transformer,
4523 +             Action<U> action) {
4524 +            if (transformer == null || action == null)
4525 +                throw new NullPointerException();
4526 +            return new ForEachTransformedValueTask<K,V,U>
4527 +                (map, null, -1, transformer, action);
4528 +        }
4529 +
4530 +        /**
4531 +         * Returns a task that when invoked, returns a non-null result
4532 +         * from applying the given search function on each value, or
4533 +         * null if none.  Upon success, further element processing is
4534 +         * suppressed and the results of any other parallel
4535 +         * invocations of the search function are ignored.
4536 +         *
4537 +         * @param map the map
4538 +         * @param searchFunction a function returning a non-null
4539 +         * result on success, else null
4540 +         * @return the task
4541 +         *
4542 +         */
4543 +        public static <K,V,U> ForkJoinTask<U> searchValues
4544 +            (ConcurrentHashMapV8<K,V> map,
4545 +             Fun<? super V, ? extends U> searchFunction) {
4546 +            if (searchFunction == null) throw new NullPointerException();
4547 +            return new SearchValuesTask<K,V,U>
4548 +                (map, null, -1, searchFunction,
4549 +                 new AtomicReference<U>());
4550 +        }
4551 +
4552 +        /**
4553 +         * Returns a task that when invoked, returns the result of
4554 +         * accumulating all values using the given reducer to combine
4555 +         * values, or null if none.
4556 +         *
4557 +         * @param map the map
4558 +         * @param reducer a commutative associative combining function
4559 +         * @return the task
4560 +         */
4561 +        public static <K,V> ForkJoinTask<V> reduceValues
4562 +            (ConcurrentHashMapV8<K,V> map,
4563 +             BiFun<? super V, ? super V, ? extends V> reducer) {
4564 +            if (reducer == null) throw new NullPointerException();
4565 +            return new ReduceValuesTask<K,V>
4566 +                (map, null, -1, null, reducer);
4567 +        }
4568 +
4569 +        /**
4570 +         * Returns a task that when invoked, returns the result of
4571 +         * accumulating the given transformation of all values using the
4572 +         * given reducer to combine values, or null if none.
4573 +         *
4574 +         * @param map the map
4575 +         * @param transformer a function returning the transformation
4576 +         * for an element, or null of there is no transformation (in
4577 +         * which case it is not combined).
4578 +         * @param reducer a commutative associative combining function
4579 +         * @return the task
4580 +         */
4581 +        public static <K,V,U> ForkJoinTask<U> reduceValues
4582 +            (ConcurrentHashMapV8<K,V> map,
4583 +             Fun<? super V, ? extends U> transformer,
4584 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4585 +            if (transformer == null || reducer == null)
4586 +                throw new NullPointerException();
4587 +            return new MapReduceValuesTask<K,V,U>
4588 +                (map, null, -1, null, transformer, reducer);
4589 +        }
4590 +
4591 +        /**
4592 +         * Returns a task that when invoked, returns the result of
4593 +         * accumulating the given transformation of all values using the
4594 +         * given reducer to combine values, and the given basis as an
4595 +         * identity value.
4596 +         *
4597 +         * @param map the map
4598 +         * @param transformer a function returning the transformation
4599 +         * for an element
4600 +         * @param basis the identity (initial default value) for the reduction
4601 +         * @param reducer a commutative associative combining function
4602 +         * @return the task
4603 +         */
4604 +        public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
4605 +            (ConcurrentHashMapV8<K,V> map,
4606 +             ObjectToDouble<? super V> transformer,
4607 +             double basis,
4608 +             DoubleByDoubleToDouble reducer) {
4609 +            if (transformer == null || reducer == null)
4610 +                throw new NullPointerException();
4611 +            return new MapReduceValuesToDoubleTask<K,V>
4612 +                (map, null, -1, null, transformer, basis, reducer);
4613 +        }
4614 +
4615 +        /**
4616 +         * Returns a task that when invoked, returns the result of
4617 +         * accumulating the given transformation of all values using the
4618 +         * given reducer to combine values, and the given basis as an
4619 +         * identity value.
4620 +         *
4621 +         * @param map the map
4622 +         * @param transformer a function returning the transformation
4623 +         * for an element
4624 +         * @param basis the identity (initial default value) for the reduction
4625 +         * @param reducer a commutative associative combining function
4626 +         * @return the task
4627 +         */
4628 +        public static <K,V> ForkJoinTask<Long> reduceValuesToLong
4629 +            (ConcurrentHashMapV8<K,V> map,
4630 +             ObjectToLong<? super V> transformer,
4631 +             long basis,
4632 +             LongByLongToLong reducer) {
4633 +            if (transformer == null || reducer == null)
4634 +                throw new NullPointerException();
4635 +            return new MapReduceValuesToLongTask<K,V>
4636 +                (map, null, -1, null, transformer, basis, reducer);
4637 +        }
4638 +
4639 +        /**
4640 +         * Returns a task that when invoked, returns the result of
4641 +         * accumulating the given transformation of all values using the
4642 +         * given reducer to combine values, and the given basis as an
4643 +         * identity value.
4644 +         *
4645 +         * @param map the map
4646 +         * @param transformer a function returning the transformation
4647 +         * for an element
4648 +         * @param basis the identity (initial default value) for the reduction
4649 +         * @param reducer a commutative associative combining function
4650 +         * @return the task
4651 +         */
4652 +        public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
4653 +            (ConcurrentHashMapV8<K,V> map,
4654 +             ObjectToInt<? super V> transformer,
4655 +             int basis,
4656 +             IntByIntToInt reducer) {
4657 +            if (transformer == null || reducer == null)
4658 +                throw new NullPointerException();
4659 +            return new MapReduceValuesToIntTask<K,V>
4660 +                (map, null, -1, null, transformer, basis, reducer);
4661 +        }
4662 +
4663 +        /**
4664 +         * Returns a task that when invoked, perform the given action
4665 +         * for each entry.
4666 +         *
4667 +         * @param map the map
4668 +         * @param action the action
4669 +         */
4670 +        public static <K,V> ForkJoinTask<Void> forEachEntry
4671 +            (ConcurrentHashMapV8<K,V> map,
4672 +             Action<Map.Entry<K,V>> action) {
4673 +            if (action == null) throw new NullPointerException();
4674 +            return new ForEachEntryTask<K,V>(map, null, -1, action);
4675 +        }
4676 +
4677 +        /**
4678 +         * Returns a task that when invoked, perform the given action
4679 +         * for each non-null transformation of each entry.
4680 +         *
4681 +         * @param map the map
4682 +         * @param transformer a function returning the transformation
4683 +         * for an element, or null of there is no transformation (in
4684 +         * which case the action is not applied).
4685 +         * @param action the action
4686 +         */
4687 +        public static <K,V,U> ForkJoinTask<Void> forEachEntry
4688 +            (ConcurrentHashMapV8<K,V> map,
4689 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
4690 +             Action<U> action) {
4691 +            if (transformer == null || action == null)
4692 +                throw new NullPointerException();
4693 +            return new ForEachTransformedEntryTask<K,V,U>
4694 +                (map, null, -1, transformer, action);
4695 +        }
4696 +
4697 +        /**
4698 +         * Returns a task that when invoked, returns a non-null result
4699 +         * from applying the given search function on each entry, or
4700 +         * null if none.  Upon success, further element processing is
4701 +         * suppressed and the results of any other parallel
4702 +         * invocations of the search function are ignored.
4703 +         *
4704 +         * @param map the map
4705 +         * @param searchFunction a function returning a non-null
4706 +         * result on success, else null
4707 +         * @return the task
4708 +         *
4709 +         */
4710 +        public static <K,V,U> ForkJoinTask<U> searchEntries
4711 +            (ConcurrentHashMapV8<K,V> map,
4712 +             Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4713 +            if (searchFunction == null) throw new NullPointerException();
4714 +            return new SearchEntriesTask<K,V,U>
4715 +                (map, null, -1, searchFunction,
4716 +                 new AtomicReference<U>());
4717 +        }
4718 +
4719 +        /**
4720 +         * Returns a task that when invoked, returns the result of
4721 +         * accumulating all entries using the given reducer to combine
4722 +         * values, or null if none.
4723 +         *
4724 +         * @param map the map
4725 +         * @param reducer a commutative associative combining function
4726 +         * @return the task
4727 +         */
4728 +        public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
4729 +            (ConcurrentHashMapV8<K,V> map,
4730 +             BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4731 +            if (reducer == null) throw new NullPointerException();
4732 +            return new ReduceEntriesTask<K,V>
4733 +                (map, null, -1, null, reducer);
4734 +        }
4735 +
4736 +        /**
4737 +         * Returns a task that when invoked, returns the result of
4738 +         * accumulating the given transformation of all entries using the
4739 +         * given reducer to combine values, or null if none.
4740 +         *
4741 +         * @param map the map
4742 +         * @param transformer a function returning the transformation
4743 +         * for an element, or null of there is no transformation (in
4744 +         * which case it is not combined).
4745 +         * @param reducer a commutative associative combining function
4746 +         * @return the task
4747 +         */
4748 +        public static <K,V,U> ForkJoinTask<U> reduceEntries
4749 +            (ConcurrentHashMapV8<K,V> map,
4750 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
4751 +             BiFun<? super U, ? super U, ? extends U> reducer) {
4752 +            if (transformer == null || reducer == null)
4753 +                throw new NullPointerException();
4754 +            return new MapReduceEntriesTask<K,V,U>
4755 +                (map, null, -1, null, transformer, reducer);
4756 +        }
4757 +
4758 +        /**
4759 +         * Returns a task that when invoked, returns the result of
4760 +         * accumulating the given transformation of all entries using the
4761 +         * given reducer to combine values, and the given basis as an
4762 +         * identity value.
4763 +         *
4764 +         * @param map the map
4765 +         * @param transformer a function returning the transformation
4766 +         * for an element
4767 +         * @param basis the identity (initial default value) for the reduction
4768 +         * @param reducer a commutative associative combining function
4769 +         * @return the task
4770 +         */
4771 +        public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
4772 +            (ConcurrentHashMapV8<K,V> map,
4773 +             ObjectToDouble<Map.Entry<K,V>> transformer,
4774 +             double basis,
4775 +             DoubleByDoubleToDouble reducer) {
4776 +            if (transformer == null || reducer == null)
4777 +                throw new NullPointerException();
4778 +            return new MapReduceEntriesToDoubleTask<K,V>
4779 +                (map, null, -1, null, transformer, basis, reducer);
4780 +        }
4781 +
4782 +        /**
4783 +         * Returns a task that when invoked, returns the result of
4784 +         * accumulating the given transformation of all entries using the
4785 +         * given reducer to combine values, and the given basis as an
4786 +         * identity value.
4787 +         *
4788 +         * @param map the map
4789 +         * @param transformer a function returning the transformation
4790 +         * for an element
4791 +         * @param basis the identity (initial default value) for the reduction
4792 +         * @param reducer a commutative associative combining function
4793 +         * @return the task
4794 +         */
4795 +        public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
4796 +            (ConcurrentHashMapV8<K,V> map,
4797 +             ObjectToLong<Map.Entry<K,V>> transformer,
4798 +             long basis,
4799 +             LongByLongToLong reducer) {
4800 +            if (transformer == null || reducer == null)
4801 +                throw new NullPointerException();
4802 +            return new MapReduceEntriesToLongTask<K,V>
4803 +                (map, null, -1, null, transformer, basis, reducer);
4804 +        }
4805 +
4806 +        /**
4807 +         * Returns a task that when invoked, returns the result of
4808 +         * accumulating the given transformation of all entries using the
4809 +         * given reducer to combine values, and the given basis as an
4810 +         * identity value.
4811 +         *
4812 +         * @param map the map
4813 +         * @param transformer a function returning the transformation
4814 +         * for an element
4815 +         * @param basis the identity (initial default value) for the reduction
4816 +         * @param reducer a commutative associative combining function
4817 +         * @return the task
4818 +         */
4819 +        public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
4820 +            (ConcurrentHashMapV8<K,V> map,
4821 +             ObjectToInt<Map.Entry<K,V>> transformer,
4822 +             int basis,
4823 +             IntByIntToInt reducer) {
4824 +            if (transformer == null || reducer == null)
4825 +                throw new NullPointerException();
4826 +            return new MapReduceEntriesToIntTask<K,V>
4827 +                (map, null, -1, null, transformer, basis, reducer);
4828 +        }
4829 +    }
4830 +
4831 +    // -------------------------------------------------------
4832 +
4833 +    /**
4834 +     * Base for FJ tasks for bulk operations. This adds a variant of
4835 +     * CountedCompleters and some split and merge bookkeeping to
4836 +     * iterator functionality. The forEach and reduce methods are
4837 +     * similar to those illustrated in CountedCompleter documentation,
4838 +     * except that bottom-up reduction completions perform them within
4839 +     * their compute methods. The search methods are like forEach
4840 +     * except they continually poll for success and exit early.  Also,
4841 +     * exceptions are handled in a simpler manner, by just trying to
4842 +     * complete root task exceptionally.
4843 +     */
4844 +    @SuppressWarnings("serial") static abstract class BulkTask<K,V,R> extends Traverser<K,V,R> {
4845 +        final BulkTask<K,V,?> parent;  // completion target
4846 +        int batch;                     // split control; -1 for unknown
4847 +        int pending;                   // completion control
4848 +
4849 +        BulkTask(ConcurrentHashMapV8<K,V> map, BulkTask<K,V,?> parent,
4850 +                 int batch) {
4851 +            super(map);
4852 +            this.parent = parent;
4853 +            this.batch = batch;
4854 +            if (parent != null && map != null) { // split parent
4855 +                Node[] t;
4856 +                if ((t = parent.tab) == null &&
4857 +                    (t = parent.tab = map.table) != null)
4858 +                    parent.baseLimit = parent.baseSize = t.length;
4859 +                this.tab = t;
4860 +                this.baseSize = parent.baseSize;
4861 +                int hi = this.baseLimit = parent.baseLimit;
4862 +                parent.baseLimit = this.index = this.baseIndex =
4863 +                    (hi + parent.baseIndex + 1) >>> 1;
4864 +            }
4865 +        }
4866 +
4867 +        // FJ methods
4868 +
4869 +        /**
4870 +         * Propagates completion. Note that all reduce actions
4871 +         * bypass this method to combine while completing.
4872 +         */
4873 +        final void tryComplete() {
4874 +            BulkTask<K,V,?> a = this, s = a;
4875 +            for (int c;;) {
4876 +                if ((c = a.pending) == 0) {
4877 +                    if ((a = (s = a).parent) == null) {
4878 +                        s.quietlyComplete();
4879 +                        break;
4880 +                    }
4881 +                }
4882 +                else if (U.compareAndSwapInt(a, PENDING, c, c - 1))
4883 +                    break;
4884 +            }
4885 +        }
4886 +
4887 +        /**
4888 +         * Forces root task to complete.
4889 +         * @param ex if null, complete normally, else exceptionally
4890 +         * @return false to simplify use
4891 +         */
4892 +        final boolean tryCompleteComputation(Throwable ex) {
4893 +            for (BulkTask<K,V,?> a = this;;) {
4894 +                BulkTask<K,V,?> p = a.parent;
4895 +                if (p == null) {
4896 +                    if (ex != null)
4897 +                        a.completeExceptionally(ex);
4898 +                    else
4899 +                        a.quietlyComplete();
4900 +                    return false;
4901 +                }
4902 +                a = p;
4903 +            }
4904 +        }
4905 +
4906 +        /**
4907 +         * Version of tryCompleteComputation for function screening checks
4908 +         */
4909 +        final boolean abortOnNullFunction() {
4910 +            return tryCompleteComputation(new Error("Unexpected null function"));
4911 +        }
4912 +
4913 +        // utilities
4914 +
4915 +        /** CompareAndSet pending count */
4916 +        final boolean casPending(int cmp, int val) {
4917 +            return U.compareAndSwapInt(this, PENDING, cmp, val);
4918 +        }
4919 +
4920 +        /**
4921 +         * Returns approx exp2 of the number of times (minus one) to
4922 +         * split task by two before executing leaf action. This value
4923 +         * is faster to compute and more convenient to use as a guide
4924 +         * to splitting than is the depth, since it is used while
4925 +         * dividing by two anyway.
4926 +         */
4927 +        final int batch() {
4928 +            ConcurrentHashMapV8<K, V> m; int b; Node[] t;
4929 +            if ((b = batch) < 0 && (m = map) != null) { // force initialization
4930 +                if ((t = tab) == null && (t = tab = m.table) != null)
4931 +                    baseLimit = baseSize = t.length;
4932 +                if (t != null) {
4933 +                    long n = m.counter.sum();
4934 +                    int sp = getPool().getParallelism() << 3; // slack of 8
4935 +                    b = batch = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
4936 +                }
4937 +            }
4938 +            return b;
4939 +        }
4940 +
4941 +        /**
4942 +         * Returns exportable snapshot entry.
4943 +         */
4944 +        static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
4945 +            return new AbstractMap.SimpleEntry<K,V>(k, v);
4946 +        }
4947 +
4948 +        // Unsafe mechanics
4949 +        private static final sun.misc.Unsafe U;
4950 +        private static final long PENDING;
4951 +        static {
4952 +            try {
4953 +                U = getUnsafe();
4954 +                PENDING = U.objectFieldOffset
4955 +                    (BulkTask.class.getDeclaredField("pending"));
4956 +            } catch (Exception e) {
4957 +                throw new Error(e);
4958 +            }
4959 +        }
4960 +    }
4961 +
4962 +    /*
4963 +     * Task classes. Coded in a regular but ugly format/style to
4964 +     * simplify checks that each variant differs in the right way from
4965 +     * others.
4966 +     */
4967 +
4968 +    @SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
4969 +        extends BulkTask<K,V,Void> {
4970 +        final Action<K> action;
4971 +        ForEachKeyTask
4972 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
4973 +             Action<K> action) {
4974 +            super(m, p, b);
4975 +            this.action = action;
4976 +        }
4977 +        @SuppressWarnings("unchecked") public final boolean exec() {
4978 +            final Action<K> action = this.action;
4979 +            if (action == null)
4980 +                return abortOnNullFunction();
4981 +            try {
4982 +                int b = batch(), c;
4983 +                while (b > 1 && baseIndex != baseLimit) {
4984 +                    do {} while (!casPending(c = pending, c+1));
4985 +                    new ForEachKeyTask<K,V>(map, this, b >>>= 1, action).fork();
4986 +                }
4987 +                while (advance() != null)
4988 +                    action.apply((K)nextKey);
4989 +                tryComplete();
4990 +            } catch (Throwable ex) {
4991 +                return tryCompleteComputation(ex);
4992 +            }
4993 +            return false;
4994 +        }
4995 +    }
4996 +
4997 +    @SuppressWarnings("serial") static final class ForEachValueTask<K,V>
4998 +        extends BulkTask<K,V,Void> {
4999 +        final Action<V> action;
5000 +        ForEachValueTask
5001 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5002 +             Action<V> action) {
5003 +            super(m, p, b);
5004 +            this.action = action;
5005 +        }
5006 +        @SuppressWarnings("unchecked") public final boolean exec() {
5007 +            final Action<V> action = this.action;
5008 +            if (action == null)
5009 +                return abortOnNullFunction();
5010 +            try {
5011 +                int b = batch(), c;
5012 +                while (b > 1 && baseIndex != baseLimit) {
5013 +                    do {} while (!casPending(c = pending, c+1));
5014 +                    new ForEachValueTask<K,V>(map, this, b >>>= 1, action).fork();
5015 +                }
5016 +                Object v;
5017 +                while ((v = advance()) != null)
5018 +                    action.apply((V)v);
5019 +                tryComplete();
5020 +            } catch (Throwable ex) {
5021 +                return tryCompleteComputation(ex);
5022 +            }
5023 +            return false;
5024 +        }
5025 +    }
5026 +
5027 +    @SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5028 +        extends BulkTask<K,V,Void> {
5029 +        final Action<Entry<K,V>> action;
5030 +        ForEachEntryTask
5031 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5032 +             Action<Entry<K,V>> action) {
5033 +            super(m, p, b);
5034 +            this.action = action;
5035 +        }
5036 +        @SuppressWarnings("unchecked") public final boolean exec() {
5037 +            final Action<Entry<K,V>> action = this.action;
5038 +            if (action == null)
5039 +                return abortOnNullFunction();
5040 +            try {
5041 +                int b = batch(), c;
5042 +                while (b > 1 && baseIndex != baseLimit) {
5043 +                    do {} while (!casPending(c = pending, c+1));
5044 +                    new ForEachEntryTask<K,V>(map, this, b >>>= 1, action).fork();
5045 +                }
5046 +                Object v;
5047 +                while ((v = advance()) != null)
5048 +                    action.apply(entryFor((K)nextKey, (V)v));
5049 +                tryComplete();
5050 +            } catch (Throwable ex) {
5051 +                return tryCompleteComputation(ex);
5052 +            }
5053 +            return false;
5054 +        }
5055 +    }
5056 +
5057 +    @SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5058 +        extends BulkTask<K,V,Void> {
5059 +        final BiAction<K,V> action;
5060 +        ForEachMappingTask
5061 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5062 +             BiAction<K,V> action) {
5063 +            super(m, p, b);
5064 +            this.action = action;
5065 +        }
5066 +        @SuppressWarnings("unchecked") public final boolean exec() {
5067 +            final BiAction<K,V> action = this.action;
5068 +            if (action == null)
5069 +                return abortOnNullFunction();
5070 +            try {
5071 +                int b = batch(), c;
5072 +                while (b > 1 && baseIndex != baseLimit) {
5073 +                    do {} while (!casPending(c = pending, c+1));
5074 +                    new ForEachMappingTask<K,V>(map, this, b >>>= 1,
5075 +                                                action).fork();
5076 +                }
5077 +                Object v;
5078 +                while ((v = advance()) != null)
5079 +                    action.apply((K)nextKey, (V)v);
5080 +                tryComplete();
5081 +            } catch (Throwable ex) {
5082 +                return tryCompleteComputation(ex);
5083 +            }
5084 +            return false;
5085 +        }
5086 +    }
5087 +
5088 +    @SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5089 +        extends BulkTask<K,V,Void> {
5090 +        final Fun<? super K, ? extends U> transformer;
5091 +        final Action<U> action;
5092 +        ForEachTransformedKeyTask
5093 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5094 +             Fun<? super K, ? extends U> transformer,
5095 +             Action<U> action) {
5096 +            super(m, p, b);
5097 +            this.transformer = transformer;
5098 +            this.action = action;
5099 +
5100 +        }
5101 +        @SuppressWarnings("unchecked") public final boolean exec() {
5102 +            final Fun<? super K, ? extends U> transformer =
5103 +                this.transformer;
5104 +            final Action<U> action = this.action;
5105 +            if (transformer == null || action == null)
5106 +                return abortOnNullFunction();
5107 +            try {
5108 +                int b = batch(), c;
5109 +                while (b > 1 && baseIndex != baseLimit) {
5110 +                    do {} while (!casPending(c = pending, c+1));
5111 +                    new ForEachTransformedKeyTask<K,V,U>
5112 +                        (map, this, b >>>= 1, transformer, action).fork();
5113 +                }
5114 +                U u;
5115 +                while (advance() != null) {
5116 +                    if ((u = transformer.apply((K)nextKey)) != null)
5117 +                        action.apply(u);
5118 +                }
5119 +                tryComplete();
5120 +            } catch (Throwable ex) {
5121 +                return tryCompleteComputation(ex);
5122 +            }
5123 +            return false;
5124 +        }
5125 +    }
5126 +
5127 +    @SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5128 +        extends BulkTask<K,V,Void> {
5129 +        final Fun<? super V, ? extends U> transformer;
5130 +        final Action<U> action;
5131 +        ForEachTransformedValueTask
5132 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5133 +             Fun<? super V, ? extends U> transformer,
5134 +             Action<U> action) {
5135 +            super(m, p, b);
5136 +            this.transformer = transformer;
5137 +            this.action = action;
5138 +
5139 +        }
5140 +        @SuppressWarnings("unchecked") public final boolean exec() {
5141 +            final Fun<? super V, ? extends U> transformer =
5142 +                this.transformer;
5143 +            final Action<U> action = this.action;
5144 +            if (transformer == null || action == null)
5145 +                return abortOnNullFunction();
5146 +            try {
5147 +                int b = batch(), c;
5148 +                while (b > 1 && baseIndex != baseLimit) {
5149 +                    do {} while (!casPending(c = pending, c+1));
5150 +                    new ForEachTransformedValueTask<K,V,U>
5151 +                        (map, this, b >>>= 1, transformer, action).fork();
5152 +                }
5153 +                Object v; U u;
5154 +                while ((v = advance()) != null) {
5155 +                    if ((u = transformer.apply((V)v)) != null)
5156 +                        action.apply(u);
5157 +                }
5158 +                tryComplete();
5159 +            } catch (Throwable ex) {
5160 +                return tryCompleteComputation(ex);
5161 +            }
5162 +            return false;
5163 +        }
5164 +    }
5165 +
5166 +    @SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5167 +        extends BulkTask<K,V,Void> {
5168 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5169 +        final Action<U> action;
5170 +        ForEachTransformedEntryTask
5171 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5172 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5173 +             Action<U> action) {
5174 +            super(m, p, b);
5175 +            this.transformer = transformer;
5176 +            this.action = action;
5177 +
5178 +        }
5179 +        @SuppressWarnings("unchecked") public final boolean exec() {
5180 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5181 +                this.transformer;
5182 +            final Action<U> action = this.action;
5183 +            if (transformer == null || action == null)
5184 +                return abortOnNullFunction();
5185 +            try {
5186 +                int b = batch(), c;
5187 +                while (b > 1 && baseIndex != baseLimit) {
5188 +                    do {} while (!casPending(c = pending, c+1));
5189 +                    new ForEachTransformedEntryTask<K,V,U>
5190 +                        (map, this, b >>>= 1, transformer, action).fork();
5191 +                }
5192 +                Object v; U u;
5193 +                while ((v = advance()) != null) {
5194 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5195 +                        action.apply(u);
5196 +                }
5197 +                tryComplete();
5198 +            } catch (Throwable ex) {
5199 +                return tryCompleteComputation(ex);
5200 +            }
5201 +            return false;
5202 +        }
5203 +    }
5204 +
5205 +    @SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5206 +        extends BulkTask<K,V,Void> {
5207 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5208 +        final Action<U> action;
5209 +        ForEachTransformedMappingTask
5210 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5211 +             BiFun<? super K, ? super V, ? extends U> transformer,
5212 +             Action<U> action) {
5213 +            super(m, p, b);
5214 +            this.transformer = transformer;
5215 +            this.action = action;
5216 +
5217 +        }
5218 +        @SuppressWarnings("unchecked") public final boolean exec() {
5219 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5220 +                this.transformer;
5221 +            final Action<U> action = this.action;
5222 +            if (transformer == null || action == null)
5223 +                return abortOnNullFunction();
5224 +            try {
5225 +                int b = batch(), c;
5226 +                while (b > 1 && baseIndex != baseLimit) {
5227 +                    do {} while (!casPending(c = pending, c+1));
5228 +                    new ForEachTransformedMappingTask<K,V,U>
5229 +                        (map, this, b >>>= 1, transformer, action).fork();
5230 +                }
5231 +                Object v; U u;
5232 +                while ((v = advance()) != null) {
5233 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5234 +                        action.apply(u);
5235 +                }
5236 +                tryComplete();
5237 +            } catch (Throwable ex) {
5238 +                return tryCompleteComputation(ex);
5239 +            }
5240 +            return false;
5241 +        }
5242 +    }
5243 +
5244 +    @SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5245 +        extends BulkTask<K,V,U> {
5246 +        final Fun<? super K, ? extends U> searchFunction;
5247 +        final AtomicReference<U> result;
5248 +        SearchKeysTask
5249 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5250 +             Fun<? super K, ? extends U> searchFunction,
5251 +             AtomicReference<U> result) {
5252 +            super(m, p, b);
5253 +            this.searchFunction = searchFunction; this.result = result;
5254 +        }
5255 +        @SuppressWarnings("unchecked") public final boolean exec() {
5256 +            AtomicReference<U> result = this.result;
5257 +            final Fun<? super K, ? extends U> searchFunction =
5258 +                this.searchFunction;
5259 +            if (searchFunction == null || result == null)
5260 +                return abortOnNullFunction();
5261 +            try {
5262 +                int b = batch(), c;
5263 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5264 +                    do {} while (!casPending(c = pending, c+1));
5265 +                    new SearchKeysTask<K,V,U>(map, this, b >>>= 1,
5266 +                                              searchFunction, result).fork();
5267 +                }
5268 +                U u;
5269 +                while (result.get() == null && advance() != null) {
5270 +                    if ((u = searchFunction.apply((K)nextKey)) != null) {
5271 +                        if (result.compareAndSet(null, u))
5272 +                            tryCompleteComputation(null);
5273 +                        break;
5274 +                    }
5275 +                }
5276 +                tryComplete();
5277 +            } catch (Throwable ex) {
5278 +                return tryCompleteComputation(ex);
5279 +            }
5280 +            return false;
5281 +        }
5282 +        public final U getRawResult() { return result.get(); }
5283 +    }
5284 +
5285 +    @SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5286 +        extends BulkTask<K,V,U> {
5287 +        final Fun<? super V, ? extends U> searchFunction;
5288 +        final AtomicReference<U> result;
5289 +        SearchValuesTask
5290 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5291 +             Fun<? super V, ? extends U> searchFunction,
5292 +             AtomicReference<U> result) {
5293 +            super(m, p, b);
5294 +            this.searchFunction = searchFunction; this.result = result;
5295 +        }
5296 +        @SuppressWarnings("unchecked") public final boolean exec() {
5297 +            AtomicReference<U> result = this.result;
5298 +            final Fun<? super V, ? extends U> searchFunction =
5299 +                this.searchFunction;
5300 +            if (searchFunction == null || result == null)
5301 +                return abortOnNullFunction();
5302 +            try {
5303 +                int b = batch(), c;
5304 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5305 +                    do {} while (!casPending(c = pending, c+1));
5306 +                    new SearchValuesTask<K,V,U>(map, this, b >>>= 1,
5307 +                                                searchFunction, result).fork();
5308 +                }
5309 +                Object v; U u;
5310 +                while (result.get() == null && (v = advance()) != null) {
5311 +                    if ((u = searchFunction.apply((V)v)) != null) {
5312 +                        if (result.compareAndSet(null, u))
5313 +                            tryCompleteComputation(null);
5314 +                        break;
5315 +                    }
5316 +                }
5317 +                tryComplete();
5318 +            } catch (Throwable ex) {
5319 +                return tryCompleteComputation(ex);
5320 +            }
5321 +            return false;
5322 +        }
5323 +        public final U getRawResult() { return result.get(); }
5324 +    }
5325 +
5326 +    @SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5327 +        extends BulkTask<K,V,U> {
5328 +        final Fun<Entry<K,V>, ? extends U> searchFunction;
5329 +        final AtomicReference<U> result;
5330 +        SearchEntriesTask
5331 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5332 +             Fun<Entry<K,V>, ? extends U> searchFunction,
5333 +             AtomicReference<U> result) {
5334 +            super(m, p, b);
5335 +            this.searchFunction = searchFunction; this.result = result;
5336 +        }
5337 +        @SuppressWarnings("unchecked") public final boolean exec() {
5338 +            AtomicReference<U> result = this.result;
5339 +            final Fun<Entry<K,V>, ? extends U> searchFunction =
5340 +                this.searchFunction;
5341 +            if (searchFunction == null || result == null)
5342 +                return abortOnNullFunction();
5343 +            try {
5344 +                int b = batch(), c;
5345 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5346 +                    do {} while (!casPending(c = pending, c+1));
5347 +                    new SearchEntriesTask<K,V,U>(map, this, b >>>= 1,
5348 +                                                 searchFunction, result).fork();
5349 +                }
5350 +                Object v; U u;
5351 +                while (result.get() == null && (v = advance()) != null) {
5352 +                    if ((u = searchFunction.apply(entryFor((K)nextKey, (V)v))) != null) {
5353 +                        if (result.compareAndSet(null, u))
5354 +                            tryCompleteComputation(null);
5355 +                        break;
5356 +                    }
5357 +                }
5358 +                tryComplete();
5359 +            } catch (Throwable ex) {
5360 +                return tryCompleteComputation(ex);
5361 +            }
5362 +            return false;
5363 +        }
5364 +        public final U getRawResult() { return result.get(); }
5365 +    }
5366 +
5367 +    @SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5368 +        extends BulkTask<K,V,U> {
5369 +        final BiFun<? super K, ? super V, ? extends U> searchFunction;
5370 +        final AtomicReference<U> result;
5371 +        SearchMappingsTask
5372 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5373 +             BiFun<? super K, ? super V, ? extends U> searchFunction,
5374 +             AtomicReference<U> result) {
5375 +            super(m, p, b);
5376 +            this.searchFunction = searchFunction; this.result = result;
5377 +        }
5378 +        @SuppressWarnings("unchecked") public final boolean exec() {
5379 +            AtomicReference<U> result = this.result;
5380 +            final BiFun<? super K, ? super V, ? extends U> searchFunction =
5381 +                this.searchFunction;
5382 +            if (searchFunction == null || result == null)
5383 +                return abortOnNullFunction();
5384 +            try {
5385 +                int b = batch(), c;
5386 +                while (b > 1 && baseIndex != baseLimit && result.get() == null) {
5387 +                    do {} while (!casPending(c = pending, c+1));
5388 +                    new SearchMappingsTask<K,V,U>(map, this, b >>>= 1,
5389 +                                                  searchFunction, result).fork();
5390 +                }
5391 +                Object v; U u;
5392 +                while (result.get() == null && (v = advance()) != null) {
5393 +                    if ((u = searchFunction.apply((K)nextKey, (V)v)) != null) {
5394 +                        if (result.compareAndSet(null, u))
5395 +                            tryCompleteComputation(null);
5396 +                        break;
5397 +                    }
5398 +                }
5399 +                tryComplete();
5400 +            } catch (Throwable ex) {
5401 +                return tryCompleteComputation(ex);
5402 +            }
5403 +            return false;
5404 +        }
5405 +        public final U getRawResult() { return result.get(); }
5406 +    }
5407 +
5408 +    @SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5409 +        extends BulkTask<K,V,K> {
5410 +        final BiFun<? super K, ? super K, ? extends K> reducer;
5411 +        K result;
5412 +        ReduceKeysTask<K,V> rights, nextRight;
5413 +        ReduceKeysTask
5414 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5415 +             ReduceKeysTask<K,V> nextRight,
5416 +             BiFun<? super K, ? super K, ? extends K> reducer) {
5417 +            super(m, p, b); this.nextRight = nextRight;
5418 +            this.reducer = reducer;
5419 +        }
5420 +        @SuppressWarnings("unchecked") public final boolean exec() {
5421 +            final BiFun<? super K, ? super K, ? extends K> reducer =
5422 +                this.reducer;
5423 +            if (reducer == null)
5424 +                return abortOnNullFunction();
5425 +            try {
5426 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5427 +                    do {} while (!casPending(c = pending, c+1));
5428 +                    (rights = new ReduceKeysTask<K,V>
5429 +                     (map, this, b >>>= 1, rights, reducer)).fork();
5430 +                }
5431 +                K r = null;
5432 +                while (advance() != null) {
5433 +                    K u = (K)nextKey;
5434 +                    r = (r == null) ? u : reducer.apply(r, u);
5435 +                }
5436 +                result = r;
5437 +                for (ReduceKeysTask<K,V> t = this, s;;) {
5438 +                    int c; BulkTask<K,V,?> par; K tr, sr;
5439 +                    if ((c = t.pending) == 0) {
5440 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5441 +                            if ((sr = s.result) != null)
5442 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5443 +                        }
5444 +                        if ((par = t.parent) == null ||
5445 +                            !(par instanceof ReduceKeysTask)) {
5446 +                            t.quietlyComplete();
5447 +                            break;
5448 +                        }
5449 +                        t = (ReduceKeysTask<K,V>)par;
5450 +                    }
5451 +                    else if (t.casPending(c, c - 1))
5452 +                        break;
5453 +                }
5454 +            } catch (Throwable ex) {
5455 +                return tryCompleteComputation(ex);
5456 +            }
5457 +            return false;
5458 +        }
5459 +        public final K getRawResult() { return result; }
5460 +    }
5461 +
5462 +    @SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5463 +        extends BulkTask<K,V,V> {
5464 +        final BiFun<? super V, ? super V, ? extends V> reducer;
5465 +        V result;
5466 +        ReduceValuesTask<K,V> rights, nextRight;
5467 +        ReduceValuesTask
5468 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5469 +             ReduceValuesTask<K,V> nextRight,
5470 +             BiFun<? super V, ? super V, ? extends V> reducer) {
5471 +            super(m, p, b); this.nextRight = nextRight;
5472 +            this.reducer = reducer;
5473 +        }
5474 +        @SuppressWarnings("unchecked") public final boolean exec() {
5475 +            final BiFun<? super V, ? super V, ? extends V> reducer =
5476 +                this.reducer;
5477 +            if (reducer == null)
5478 +                return abortOnNullFunction();
5479 +            try {
5480 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5481 +                    do {} while (!casPending(c = pending, c+1));
5482 +                    (rights = new ReduceValuesTask<K,V>
5483 +                     (map, this, b >>>= 1, rights, reducer)).fork();
5484 +                }
5485 +                V r = null;
5486 +                Object v;
5487 +                while ((v = advance()) != null) {
5488 +                    V u = (V)v;
5489 +                    r = (r == null) ? u : reducer.apply(r, u);
5490 +                }
5491 +                result = r;
5492 +                for (ReduceValuesTask<K,V> t = this, s;;) {
5493 +                    int c; BulkTask<K,V,?> par; V tr, sr;
5494 +                    if ((c = t.pending) == 0) {
5495 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5496 +                            if ((sr = s.result) != null)
5497 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5498 +                        }
5499 +                        if ((par = t.parent) == null ||
5500 +                            !(par instanceof ReduceValuesTask)) {
5501 +                            t.quietlyComplete();
5502 +                            break;
5503 +                        }
5504 +                        t = (ReduceValuesTask<K,V>)par;
5505 +                    }
5506 +                    else if (t.casPending(c, c - 1))
5507 +                        break;
5508 +                }
5509 +            } catch (Throwable ex) {
5510 +                return tryCompleteComputation(ex);
5511 +            }
5512 +            return false;
5513 +        }
5514 +        public final V getRawResult() { return result; }
5515 +    }
5516 +
5517 +    @SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
5518 +        extends BulkTask<K,V,Map.Entry<K,V>> {
5519 +        final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5520 +        Map.Entry<K,V> result;
5521 +        ReduceEntriesTask<K,V> rights, nextRight;
5522 +        ReduceEntriesTask
5523 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5524 +             ReduceEntriesTask<K,V> nextRight,
5525 +             BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5526 +            super(m, p, b); this.nextRight = nextRight;
5527 +            this.reducer = reducer;
5528 +        }
5529 +        @SuppressWarnings("unchecked") public final boolean exec() {
5530 +            final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer =
5531 +                this.reducer;
5532 +            if (reducer == null)
5533 +                return abortOnNullFunction();
5534 +            try {
5535 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5536 +                    do {} while (!casPending(c = pending, c+1));
5537 +                    (rights = new ReduceEntriesTask<K,V>
5538 +                     (map, this, b >>>= 1, rights, reducer)).fork();
5539 +                }
5540 +                Map.Entry<K,V> r = null;
5541 +                Object v;
5542 +                while ((v = advance()) != null) {
5543 +                    Map.Entry<K,V> u = entryFor((K)nextKey, (V)v);
5544 +                    r = (r == null) ? u : reducer.apply(r, u);
5545 +                }
5546 +                result = r;
5547 +                for (ReduceEntriesTask<K,V> t = this, s;;) {
5548 +                    int c; BulkTask<K,V,?> par; Map.Entry<K,V> tr, sr;
5549 +                    if ((c = t.pending) == 0) {
5550 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5551 +                            if ((sr = s.result) != null)
5552 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5553 +                        }
5554 +                        if ((par = t.parent) == null ||
5555 +                            !(par instanceof ReduceEntriesTask)) {
5556 +                            t.quietlyComplete();
5557 +                            break;
5558 +                        }
5559 +                        t = (ReduceEntriesTask<K,V>)par;
5560 +                    }
5561 +                    else if (t.casPending(c, c - 1))
5562 +                        break;
5563 +                }
5564 +            } catch (Throwable ex) {
5565 +                return tryCompleteComputation(ex);
5566 +            }
5567 +            return false;
5568 +        }
5569 +        public final Map.Entry<K,V> getRawResult() { return result; }
5570 +    }
5571 +
5572 +    @SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
5573 +        extends BulkTask<K,V,U> {
5574 +        final Fun<? super K, ? extends U> transformer;
5575 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5576 +        U result;
5577 +        MapReduceKeysTask<K,V,U> rights, nextRight;
5578 +        MapReduceKeysTask
5579 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5580 +             MapReduceKeysTask<K,V,U> nextRight,
5581 +             Fun<? super K, ? extends U> transformer,
5582 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5583 +            super(m, p, b); this.nextRight = nextRight;
5584 +            this.transformer = transformer;
5585 +            this.reducer = reducer;
5586 +        }
5587 +        @SuppressWarnings("unchecked") public final boolean exec() {
5588 +            final Fun<? super K, ? extends U> transformer =
5589 +                this.transformer;
5590 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5591 +                this.reducer;
5592 +            if (transformer == null || reducer == null)
5593 +                return abortOnNullFunction();
5594 +            try {
5595 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5596 +                    do {} while (!casPending(c = pending, c+1));
5597 +                    (rights = new MapReduceKeysTask<K,V,U>
5598 +                     (map, this, b >>>= 1, rights, transformer, reducer)).fork();
5599 +                }
5600 +                U r = null, u;
5601 +                while (advance() != null) {
5602 +                    if ((u = transformer.apply((K)nextKey)) != null)
5603 +                        r = (r == null) ? u : reducer.apply(r, u);
5604 +                }
5605 +                result = r;
5606 +                for (MapReduceKeysTask<K,V,U> t = this, s;;) {
5607 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5608 +                    if ((c = t.pending) == 0) {
5609 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5610 +                            if ((sr = s.result) != null)
5611 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5612 +                        }
5613 +                        if ((par = t.parent) == null ||
5614 +                            !(par instanceof MapReduceKeysTask)) {
5615 +                            t.quietlyComplete();
5616 +                            break;
5617 +                        }
5618 +                        t = (MapReduceKeysTask<K,V,U>)par;
5619 +                    }
5620 +                    else if (t.casPending(c, c - 1))
5621 +                        break;
5622 +                }
5623 +            } catch (Throwable ex) {
5624 +                return tryCompleteComputation(ex);
5625 +            }
5626 +            return false;
5627 +        }
5628 +        public final U getRawResult() { return result; }
5629 +    }
5630 +
5631 +    @SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
5632 +        extends BulkTask<K,V,U> {
5633 +        final Fun<? super V, ? extends U> transformer;
5634 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5635 +        U result;
5636 +        MapReduceValuesTask<K,V,U> rights, nextRight;
5637 +        MapReduceValuesTask
5638 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5639 +             MapReduceValuesTask<K,V,U> nextRight,
5640 +             Fun<? super V, ? extends U> transformer,
5641 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5642 +            super(m, p, b); this.nextRight = nextRight;
5643 +            this.transformer = transformer;
5644 +            this.reducer = reducer;
5645 +        }
5646 +        @SuppressWarnings("unchecked") public final boolean exec() {
5647 +            final Fun<? super V, ? extends U> transformer =
5648 +                this.transformer;
5649 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5650 +                this.reducer;
5651 +            if (transformer == null || reducer == null)
5652 +                return abortOnNullFunction();
5653 +            try {
5654 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5655 +                    do {} while (!casPending(c = pending, c+1));
5656 +                    (rights = new MapReduceValuesTask<K,V,U>
5657 +                     (map, this, b >>>= 1, rights, transformer, reducer)).fork();
5658 +                }
5659 +                U r = null, u;
5660 +                Object v;
5661 +                while ((v = advance()) != null) {
5662 +                    if ((u = transformer.apply((V)v)) != null)
5663 +                        r = (r == null) ? u : reducer.apply(r, u);
5664 +                }
5665 +                result = r;
5666 +                for (MapReduceValuesTask<K,V,U> t = this, s;;) {
5667 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5668 +                    if ((c = t.pending) == 0) {
5669 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5670 +                            if ((sr = s.result) != null)
5671 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5672 +                        }
5673 +                        if ((par = t.parent) == null ||
5674 +                            !(par instanceof MapReduceValuesTask)) {
5675 +                            t.quietlyComplete();
5676 +                            break;
5677 +                        }
5678 +                        t = (MapReduceValuesTask<K,V,U>)par;
5679 +                    }
5680 +                    else if (t.casPending(c, c - 1))
5681 +                        break;
5682 +                }
5683 +            } catch (Throwable ex) {
5684 +                return tryCompleteComputation(ex);
5685 +            }
5686 +            return false;
5687 +        }
5688 +        public final U getRawResult() { return result; }
5689 +    }
5690 +
5691 +    @SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
5692 +        extends BulkTask<K,V,U> {
5693 +        final Fun<Map.Entry<K,V>, ? extends U> transformer;
5694 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5695 +        U result;
5696 +        MapReduceEntriesTask<K,V,U> rights, nextRight;
5697 +        MapReduceEntriesTask
5698 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5699 +             MapReduceEntriesTask<K,V,U> nextRight,
5700 +             Fun<Map.Entry<K,V>, ? extends U> transformer,
5701 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5702 +            super(m, p, b); this.nextRight = nextRight;
5703 +            this.transformer = transformer;
5704 +            this.reducer = reducer;
5705 +        }
5706 +        @SuppressWarnings("unchecked") public final boolean exec() {
5707 +            final Fun<Map.Entry<K,V>, ? extends U> transformer =
5708 +                this.transformer;
5709 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5710 +                this.reducer;
5711 +            if (transformer == null || reducer == null)
5712 +                return abortOnNullFunction();
5713 +            try {
5714 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5715 +                    do {} while (!casPending(c = pending, c+1));
5716 +                    (rights = new MapReduceEntriesTask<K,V,U>
5717 +                     (map, this, b >>>= 1, rights, transformer, reducer)).fork();
5718 +                }
5719 +                U r = null, u;
5720 +                Object v;
5721 +                while ((v = advance()) != null) {
5722 +                    if ((u = transformer.apply(entryFor((K)nextKey, (V)v))) != null)
5723 +                        r = (r == null) ? u : reducer.apply(r, u);
5724 +                }
5725 +                result = r;
5726 +                for (MapReduceEntriesTask<K,V,U> t = this, s;;) {
5727 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5728 +                    if ((c = t.pending) == 0) {
5729 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5730 +                            if ((sr = s.result) != null)
5731 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5732 +                        }
5733 +                        if ((par = t.parent) == null ||
5734 +                            !(par instanceof MapReduceEntriesTask)) {
5735 +                            t.quietlyComplete();
5736 +                            break;
5737 +                        }
5738 +                        t = (MapReduceEntriesTask<K,V,U>)par;
5739 +                    }
5740 +                    else if (t.casPending(c, c - 1))
5741 +                        break;
5742 +                }
5743 +            } catch (Throwable ex) {
5744 +                return tryCompleteComputation(ex);
5745 +            }
5746 +            return false;
5747 +        }
5748 +        public final U getRawResult() { return result; }
5749 +    }
5750 +
5751 +    @SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
5752 +        extends BulkTask<K,V,U> {
5753 +        final BiFun<? super K, ? super V, ? extends U> transformer;
5754 +        final BiFun<? super U, ? super U, ? extends U> reducer;
5755 +        U result;
5756 +        MapReduceMappingsTask<K,V,U> rights, nextRight;
5757 +        MapReduceMappingsTask
5758 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5759 +             MapReduceMappingsTask<K,V,U> nextRight,
5760 +             BiFun<? super K, ? super V, ? extends U> transformer,
5761 +             BiFun<? super U, ? super U, ? extends U> reducer) {
5762 +            super(m, p, b); this.nextRight = nextRight;
5763 +            this.transformer = transformer;
5764 +            this.reducer = reducer;
5765 +        }
5766 +        @SuppressWarnings("unchecked") public final boolean exec() {
5767 +            final BiFun<? super K, ? super V, ? extends U> transformer =
5768 +                this.transformer;
5769 +            final BiFun<? super U, ? super U, ? extends U> reducer =
5770 +                this.reducer;
5771 +            if (transformer == null || reducer == null)
5772 +                return abortOnNullFunction();
5773 +            try {
5774 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5775 +                    do {} while (!casPending(c = pending, c+1));
5776 +                    (rights = new MapReduceMappingsTask<K,V,U>
5777 +                     (map, this, b >>>= 1, rights, transformer, reducer)).fork();
5778 +                }
5779 +                U r = null, u;
5780 +                Object v;
5781 +                while ((v = advance()) != null) {
5782 +                    if ((u = transformer.apply((K)nextKey, (V)v)) != null)
5783 +                        r = (r == null) ? u : reducer.apply(r, u);
5784 +                }
5785 +                result = r;
5786 +                for (MapReduceMappingsTask<K,V,U> t = this, s;;) {
5787 +                    int c; BulkTask<K,V,?> par; U tr, sr;
5788 +                    if ((c = t.pending) == 0) {
5789 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5790 +                            if ((sr = s.result) != null)
5791 +                                t.result = (tr = t.result) == null? sr : reducer.apply(tr, sr);
5792 +                        }
5793 +                        if ((par = t.parent) == null ||
5794 +                            !(par instanceof MapReduceMappingsTask)) {
5795 +                            t.quietlyComplete();
5796 +                            break;
5797 +                        }
5798 +                        t = (MapReduceMappingsTask<K,V,U>)par;
5799 +                    }
5800 +                    else if (t.casPending(c, c - 1))
5801 +                        break;
5802 +                }
5803 +            } catch (Throwable ex) {
5804 +                return tryCompleteComputation(ex);
5805 +            }
5806 +            return false;
5807 +        }
5808 +        public final U getRawResult() { return result; }
5809 +    }
5810 +
5811 +    @SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
5812 +        extends BulkTask<K,V,Double> {
5813 +        final ObjectToDouble<? super K> transformer;
5814 +        final DoubleByDoubleToDouble reducer;
5815 +        final double basis;
5816 +        double result;
5817 +        MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5818 +        MapReduceKeysToDoubleTask
5819 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5820 +             MapReduceKeysToDoubleTask<K,V> nextRight,
5821 +             ObjectToDouble<? super K> transformer,
5822 +             double basis,
5823 +             DoubleByDoubleToDouble reducer) {
5824 +            super(m, p, b); this.nextRight = nextRight;
5825 +            this.transformer = transformer;
5826 +            this.basis = basis; this.reducer = reducer;
5827 +        }
5828 +        @SuppressWarnings("unchecked") public final boolean exec() {
5829 +            final ObjectToDouble<? super K> transformer =
5830 +                this.transformer;
5831 +            final DoubleByDoubleToDouble reducer = this.reducer;
5832 +            if (transformer == null || reducer == null)
5833 +                return abortOnNullFunction();
5834 +            try {
5835 +                final double id = this.basis;
5836 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5837 +                    do {} while (!casPending(c = pending, c+1));
5838 +                    (rights = new MapReduceKeysToDoubleTask<K,V>
5839 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
5840 +                }
5841 +                double r = id;
5842 +                while (advance() != null)
5843 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
5844 +                result = r;
5845 +                for (MapReduceKeysToDoubleTask<K,V> t = this, s;;) {
5846 +                    int c; BulkTask<K,V,?> par;
5847 +                    if ((c = t.pending) == 0) {
5848 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5849 +                            t.result = reducer.apply(t.result, s.result);
5850 +                        }
5851 +                        if ((par = t.parent) == null ||
5852 +                            !(par instanceof MapReduceKeysToDoubleTask)) {
5853 +                            t.quietlyComplete();
5854 +                            break;
5855 +                        }
5856 +                        t = (MapReduceKeysToDoubleTask<K,V>)par;
5857 +                    }
5858 +                    else if (t.casPending(c, c - 1))
5859 +                        break;
5860 +                }
5861 +            } catch (Throwable ex) {
5862 +                return tryCompleteComputation(ex);
5863 +            }
5864 +            return false;
5865 +        }
5866 +        public final Double getRawResult() { return result; }
5867 +    }
5868 +
5869 +    @SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
5870 +        extends BulkTask<K,V,Double> {
5871 +        final ObjectToDouble<? super V> transformer;
5872 +        final DoubleByDoubleToDouble reducer;
5873 +        final double basis;
5874 +        double result;
5875 +        MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5876 +        MapReduceValuesToDoubleTask
5877 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5878 +             MapReduceValuesToDoubleTask<K,V> nextRight,
5879 +             ObjectToDouble<? super V> transformer,
5880 +             double basis,
5881 +             DoubleByDoubleToDouble reducer) {
5882 +            super(m, p, b); this.nextRight = nextRight;
5883 +            this.transformer = transformer;
5884 +            this.basis = basis; this.reducer = reducer;
5885 +        }
5886 +        @SuppressWarnings("unchecked") public final boolean exec() {
5887 +            final ObjectToDouble<? super V> transformer =
5888 +                this.transformer;
5889 +            final DoubleByDoubleToDouble reducer = this.reducer;
5890 +            if (transformer == null || reducer == null)
5891 +                return abortOnNullFunction();
5892 +            try {
5893 +                final double id = this.basis;
5894 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5895 +                    do {} while (!casPending(c = pending, c+1));
5896 +                    (rights = new MapReduceValuesToDoubleTask<K,V>
5897 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
5898 +                }
5899 +                double r = id;
5900 +                Object v;
5901 +                while ((v = advance()) != null)
5902 +                    r = reducer.apply(r, transformer.apply((V)v));
5903 +                result = r;
5904 +                for (MapReduceValuesToDoubleTask<K,V> t = this, s;;) {
5905 +                    int c; BulkTask<K,V,?> par;
5906 +                    if ((c = t.pending) == 0) {
5907 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5908 +                            t.result = reducer.apply(t.result, s.result);
5909 +                        }
5910 +                        if ((par = t.parent) == null ||
5911 +                            !(par instanceof MapReduceValuesToDoubleTask)) {
5912 +                            t.quietlyComplete();
5913 +                            break;
5914 +                        }
5915 +                        t = (MapReduceValuesToDoubleTask<K,V>)par;
5916 +                    }
5917 +                    else if (t.casPending(c, c - 1))
5918 +                        break;
5919 +                }
5920 +            } catch (Throwable ex) {
5921 +                return tryCompleteComputation(ex);
5922 +            }
5923 +            return false;
5924 +        }
5925 +        public final Double getRawResult() { return result; }
5926 +    }
5927 +
5928 +    @SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
5929 +        extends BulkTask<K,V,Double> {
5930 +        final ObjectToDouble<Map.Entry<K,V>> transformer;
5931 +        final DoubleByDoubleToDouble reducer;
5932 +        final double basis;
5933 +        double result;
5934 +        MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5935 +        MapReduceEntriesToDoubleTask
5936 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5937 +             MapReduceEntriesToDoubleTask<K,V> nextRight,
5938 +             ObjectToDouble<Map.Entry<K,V>> transformer,
5939 +             double basis,
5940 +             DoubleByDoubleToDouble reducer) {
5941 +            super(m, p, b); this.nextRight = nextRight;
5942 +            this.transformer = transformer;
5943 +            this.basis = basis; this.reducer = reducer;
5944 +        }
5945 +        @SuppressWarnings("unchecked") public final boolean exec() {
5946 +            final ObjectToDouble<Map.Entry<K,V>> transformer =
5947 +                this.transformer;
5948 +            final DoubleByDoubleToDouble reducer = this.reducer;
5949 +            if (transformer == null || reducer == null)
5950 +                return abortOnNullFunction();
5951 +            try {
5952 +                final double id = this.basis;
5953 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
5954 +                    do {} while (!casPending(c = pending, c+1));
5955 +                    (rights = new MapReduceEntriesToDoubleTask<K,V>
5956 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
5957 +                }
5958 +                double r = id;
5959 +                Object v;
5960 +                while ((v = advance()) != null)
5961 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
5962 +                result = r;
5963 +                for (MapReduceEntriesToDoubleTask<K,V> t = this, s;;) {
5964 +                    int c; BulkTask<K,V,?> par;
5965 +                    if ((c = t.pending) == 0) {
5966 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
5967 +                            t.result = reducer.apply(t.result, s.result);
5968 +                        }
5969 +                        if ((par = t.parent) == null ||
5970 +                            !(par instanceof MapReduceEntriesToDoubleTask)) {
5971 +                            t.quietlyComplete();
5972 +                            break;
5973 +                        }
5974 +                        t = (MapReduceEntriesToDoubleTask<K,V>)par;
5975 +                    }
5976 +                    else if (t.casPending(c, c - 1))
5977 +                        break;
5978 +                }
5979 +            } catch (Throwable ex) {
5980 +                return tryCompleteComputation(ex);
5981 +            }
5982 +            return false;
5983 +        }
5984 +        public final Double getRawResult() { return result; }
5985 +    }
5986 +
5987 +    @SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
5988 +        extends BulkTask<K,V,Double> {
5989 +        final ObjectByObjectToDouble<? super K, ? super V> transformer;
5990 +        final DoubleByDoubleToDouble reducer;
5991 +        final double basis;
5992 +        double result;
5993 +        MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5994 +        MapReduceMappingsToDoubleTask
5995 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
5996 +             MapReduceMappingsToDoubleTask<K,V> nextRight,
5997 +             ObjectByObjectToDouble<? super K, ? super V> transformer,
5998 +             double basis,
5999 +             DoubleByDoubleToDouble reducer) {
6000 +            super(m, p, b); this.nextRight = nextRight;
6001 +            this.transformer = transformer;
6002 +            this.basis = basis; this.reducer = reducer;
6003 +        }
6004 +        @SuppressWarnings("unchecked") public final boolean exec() {
6005 +            final ObjectByObjectToDouble<? super K, ? super V> transformer =
6006 +                this.transformer;
6007 +            final DoubleByDoubleToDouble reducer = this.reducer;
6008 +            if (transformer == null || reducer == null)
6009 +                return abortOnNullFunction();
6010 +            try {
6011 +                final double id = this.basis;
6012 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6013 +                    do {} while (!casPending(c = pending, c+1));
6014 +                    (rights = new MapReduceMappingsToDoubleTask<K,V>
6015 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6016 +                }
6017 +                double r = id;
6018 +                Object v;
6019 +                while ((v = advance()) != null)
6020 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6021 +                result = r;
6022 +                for (MapReduceMappingsToDoubleTask<K,V> t = this, s;;) {
6023 +                    int c; BulkTask<K,V,?> par;
6024 +                    if ((c = t.pending) == 0) {
6025 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6026 +                            t.result = reducer.apply(t.result, s.result);
6027 +                        }
6028 +                        if ((par = t.parent) == null ||
6029 +                            !(par instanceof MapReduceMappingsToDoubleTask)) {
6030 +                            t.quietlyComplete();
6031 +                            break;
6032 +                        }
6033 +                        t = (MapReduceMappingsToDoubleTask<K,V>)par;
6034 +                    }
6035 +                    else if (t.casPending(c, c - 1))
6036 +                        break;
6037 +                }
6038 +            } catch (Throwable ex) {
6039 +                return tryCompleteComputation(ex);
6040 +            }
6041 +            return false;
6042 +        }
6043 +        public final Double getRawResult() { return result; }
6044 +    }
6045 +
6046 +    @SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6047 +        extends BulkTask<K,V,Long> {
6048 +        final ObjectToLong<? super K> transformer;
6049 +        final LongByLongToLong reducer;
6050 +        final long basis;
6051 +        long result;
6052 +        MapReduceKeysToLongTask<K,V> rights, nextRight;
6053 +        MapReduceKeysToLongTask
6054 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6055 +             MapReduceKeysToLongTask<K,V> nextRight,
6056 +             ObjectToLong<? super K> transformer,
6057 +             long basis,
6058 +             LongByLongToLong reducer) {
6059 +            super(m, p, b); this.nextRight = nextRight;
6060 +            this.transformer = transformer;
6061 +            this.basis = basis; this.reducer = reducer;
6062 +        }
6063 +        @SuppressWarnings("unchecked") public final boolean exec() {
6064 +            final ObjectToLong<? super K> transformer =
6065 +                this.transformer;
6066 +            final LongByLongToLong reducer = this.reducer;
6067 +            if (transformer == null || reducer == null)
6068 +                return abortOnNullFunction();
6069 +            try {
6070 +                final long id = this.basis;
6071 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6072 +                    do {} while (!casPending(c = pending, c+1));
6073 +                    (rights = new MapReduceKeysToLongTask<K,V>
6074 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6075 +                }
6076 +                long r = id;
6077 +                while (advance() != null)
6078 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6079 +                result = r;
6080 +                for (MapReduceKeysToLongTask<K,V> t = this, s;;) {
6081 +                    int c; BulkTask<K,V,?> par;
6082 +                    if ((c = t.pending) == 0) {
6083 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6084 +                            t.result = reducer.apply(t.result, s.result);
6085 +                        }
6086 +                        if ((par = t.parent) == null ||
6087 +                            !(par instanceof MapReduceKeysToLongTask)) {
6088 +                            t.quietlyComplete();
6089 +                            break;
6090 +                        }
6091 +                        t = (MapReduceKeysToLongTask<K,V>)par;
6092 +                    }
6093 +                    else if (t.casPending(c, c - 1))
6094 +                        break;
6095 +                }
6096 +            } catch (Throwable ex) {
6097 +                return tryCompleteComputation(ex);
6098 +            }
6099 +            return false;
6100 +        }
6101 +        public final Long getRawResult() { return result; }
6102 +    }
6103 +
6104 +    @SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6105 +        extends BulkTask<K,V,Long> {
6106 +        final ObjectToLong<? super V> transformer;
6107 +        final LongByLongToLong reducer;
6108 +        final long basis;
6109 +        long result;
6110 +        MapReduceValuesToLongTask<K,V> rights, nextRight;
6111 +        MapReduceValuesToLongTask
6112 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6113 +             MapReduceValuesToLongTask<K,V> nextRight,
6114 +             ObjectToLong<? super V> transformer,
6115 +             long basis,
6116 +             LongByLongToLong reducer) {
6117 +            super(m, p, b); this.nextRight = nextRight;
6118 +            this.transformer = transformer;
6119 +            this.basis = basis; this.reducer = reducer;
6120 +        }
6121 +        @SuppressWarnings("unchecked") public final boolean exec() {
6122 +            final ObjectToLong<? super V> transformer =
6123 +                this.transformer;
6124 +            final LongByLongToLong reducer = this.reducer;
6125 +            if (transformer == null || reducer == null)
6126 +                return abortOnNullFunction();
6127 +            try {
6128 +                final long id = this.basis;
6129 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6130 +                    do {} while (!casPending(c = pending, c+1));
6131 +                    (rights = new MapReduceValuesToLongTask<K,V>
6132 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6133 +                }
6134 +                long r = id;
6135 +                Object v;
6136 +                while ((v = advance()) != null)
6137 +                    r = reducer.apply(r, transformer.apply((V)v));
6138 +                result = r;
6139 +                for (MapReduceValuesToLongTask<K,V> t = this, s;;) {
6140 +                    int c; BulkTask<K,V,?> par;
6141 +                    if ((c = t.pending) == 0) {
6142 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6143 +                            t.result = reducer.apply(t.result, s.result);
6144 +                        }
6145 +                        if ((par = t.parent) == null ||
6146 +                            !(par instanceof MapReduceValuesToLongTask)) {
6147 +                            t.quietlyComplete();
6148 +                            break;
6149 +                        }
6150 +                        t = (MapReduceValuesToLongTask<K,V>)par;
6151 +                    }
6152 +                    else if (t.casPending(c, c - 1))
6153 +                        break;
6154 +                }
6155 +            } catch (Throwable ex) {
6156 +                return tryCompleteComputation(ex);
6157 +            }
6158 +            return false;
6159 +        }
6160 +        public final Long getRawResult() { return result; }
6161 +    }
6162 +
6163 +    @SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6164 +        extends BulkTask<K,V,Long> {
6165 +        final ObjectToLong<Map.Entry<K,V>> transformer;
6166 +        final LongByLongToLong reducer;
6167 +        final long basis;
6168 +        long result;
6169 +        MapReduceEntriesToLongTask<K,V> rights, nextRight;
6170 +        MapReduceEntriesToLongTask
6171 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6172 +             MapReduceEntriesToLongTask<K,V> nextRight,
6173 +             ObjectToLong<Map.Entry<K,V>> transformer,
6174 +             long basis,
6175 +             LongByLongToLong reducer) {
6176 +            super(m, p, b); this.nextRight = nextRight;
6177 +            this.transformer = transformer;
6178 +            this.basis = basis; this.reducer = reducer;
6179 +        }
6180 +        @SuppressWarnings("unchecked") public final boolean exec() {
6181 +            final ObjectToLong<Map.Entry<K,V>> transformer =
6182 +                this.transformer;
6183 +            final LongByLongToLong reducer = this.reducer;
6184 +            if (transformer == null || reducer == null)
6185 +                return abortOnNullFunction();
6186 +            try {
6187 +                final long id = this.basis;
6188 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6189 +                    do {} while (!casPending(c = pending, c+1));
6190 +                    (rights = new MapReduceEntriesToLongTask<K,V>
6191 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6192 +                }
6193 +                long r = id;
6194 +                Object v;
6195 +                while ((v = advance()) != null)
6196 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6197 +                result = r;
6198 +                for (MapReduceEntriesToLongTask<K,V> t = this, s;;) {
6199 +                    int c; BulkTask<K,V,?> par;
6200 +                    if ((c = t.pending) == 0) {
6201 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6202 +                            t.result = reducer.apply(t.result, s.result);
6203 +                        }
6204 +                        if ((par = t.parent) == null ||
6205 +                            !(par instanceof MapReduceEntriesToLongTask)) {
6206 +                            t.quietlyComplete();
6207 +                            break;
6208 +                        }
6209 +                        t = (MapReduceEntriesToLongTask<K,V>)par;
6210 +                    }
6211 +                    else if (t.casPending(c, c - 1))
6212 +                        break;
6213 +                }
6214 +            } catch (Throwable ex) {
6215 +                return tryCompleteComputation(ex);
6216 +            }
6217 +            return false;
6218 +        }
6219 +        public final Long getRawResult() { return result; }
6220 +    }
6221 +
6222 +    @SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6223 +        extends BulkTask<K,V,Long> {
6224 +        final ObjectByObjectToLong<? super K, ? super V> transformer;
6225 +        final LongByLongToLong reducer;
6226 +        final long basis;
6227 +        long result;
6228 +        MapReduceMappingsToLongTask<K,V> rights, nextRight;
6229 +        MapReduceMappingsToLongTask
6230 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6231 +             MapReduceMappingsToLongTask<K,V> nextRight,
6232 +             ObjectByObjectToLong<? super K, ? super V> transformer,
6233 +             long basis,
6234 +             LongByLongToLong reducer) {
6235 +            super(m, p, b); this.nextRight = nextRight;
6236 +            this.transformer = transformer;
6237 +            this.basis = basis; this.reducer = reducer;
6238 +        }
6239 +        @SuppressWarnings("unchecked") public final boolean exec() {
6240 +            final ObjectByObjectToLong<? super K, ? super V> transformer =
6241 +                this.transformer;
6242 +            final LongByLongToLong reducer = this.reducer;
6243 +            if (transformer == null || reducer == null)
6244 +                return abortOnNullFunction();
6245 +            try {
6246 +                final long id = this.basis;
6247 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6248 +                    do {} while (!casPending(c = pending, c+1));
6249 +                    (rights = new MapReduceMappingsToLongTask<K,V>
6250 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6251 +                }
6252 +                long r = id;
6253 +                Object v;
6254 +                while ((v = advance()) != null)
6255 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6256 +                result = r;
6257 +                for (MapReduceMappingsToLongTask<K,V> t = this, s;;) {
6258 +                    int c; BulkTask<K,V,?> par;
6259 +                    if ((c = t.pending) == 0) {
6260 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6261 +                            t.result = reducer.apply(t.result, s.result);
6262 +                        }
6263 +                        if ((par = t.parent) == null ||
6264 +                            !(par instanceof MapReduceMappingsToLongTask)) {
6265 +                            t.quietlyComplete();
6266 +                            break;
6267 +                        }
6268 +                        t = (MapReduceMappingsToLongTask<K,V>)par;
6269 +                    }
6270 +                    else if (t.casPending(c, c - 1))
6271 +                        break;
6272 +                }
6273 +            } catch (Throwable ex) {
6274 +                return tryCompleteComputation(ex);
6275 +            }
6276 +            return false;
6277 +        }
6278 +        public final Long getRawResult() { return result; }
6279 +    }
6280 +
6281 +    @SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6282 +        extends BulkTask<K,V,Integer> {
6283 +        final ObjectToInt<? super K> transformer;
6284 +        final IntByIntToInt reducer;
6285 +        final int basis;
6286 +        int result;
6287 +        MapReduceKeysToIntTask<K,V> rights, nextRight;
6288 +        MapReduceKeysToIntTask
6289 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6290 +             MapReduceKeysToIntTask<K,V> nextRight,
6291 +             ObjectToInt<? super K> transformer,
6292 +             int basis,
6293 +             IntByIntToInt reducer) {
6294 +            super(m, p, b); this.nextRight = nextRight;
6295 +            this.transformer = transformer;
6296 +            this.basis = basis; this.reducer = reducer;
6297 +        }
6298 +        @SuppressWarnings("unchecked") public final boolean exec() {
6299 +            final ObjectToInt<? super K> transformer =
6300 +                this.transformer;
6301 +            final IntByIntToInt reducer = this.reducer;
6302 +            if (transformer == null || reducer == null)
6303 +                return abortOnNullFunction();
6304 +            try {
6305 +                final int id = this.basis;
6306 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6307 +                    do {} while (!casPending(c = pending, c+1));
6308 +                    (rights = new MapReduceKeysToIntTask<K,V>
6309 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6310 +                }
6311 +                int r = id;
6312 +                while (advance() != null)
6313 +                    r = reducer.apply(r, transformer.apply((K)nextKey));
6314 +                result = r;
6315 +                for (MapReduceKeysToIntTask<K,V> t = this, s;;) {
6316 +                    int c; BulkTask<K,V,?> par;
6317 +                    if ((c = t.pending) == 0) {
6318 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6319 +                            t.result = reducer.apply(t.result, s.result);
6320 +                        }
6321 +                        if ((par = t.parent) == null ||
6322 +                            !(par instanceof MapReduceKeysToIntTask)) {
6323 +                            t.quietlyComplete();
6324 +                            break;
6325 +                        }
6326 +                        t = (MapReduceKeysToIntTask<K,V>)par;
6327 +                    }
6328 +                    else if (t.casPending(c, c - 1))
6329 +                        break;
6330 +                }
6331 +            } catch (Throwable ex) {
6332 +                return tryCompleteComputation(ex);
6333 +            }
6334 +            return false;
6335 +        }
6336 +        public final Integer getRawResult() { return result; }
6337 +    }
6338 +
6339 +    @SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6340 +        extends BulkTask<K,V,Integer> {
6341 +        final ObjectToInt<? super V> transformer;
6342 +        final IntByIntToInt reducer;
6343 +        final int basis;
6344 +        int result;
6345 +        MapReduceValuesToIntTask<K,V> rights, nextRight;
6346 +        MapReduceValuesToIntTask
6347 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6348 +             MapReduceValuesToIntTask<K,V> nextRight,
6349 +             ObjectToInt<? super V> transformer,
6350 +             int basis,
6351 +             IntByIntToInt reducer) {
6352 +            super(m, p, b); this.nextRight = nextRight;
6353 +            this.transformer = transformer;
6354 +            this.basis = basis; this.reducer = reducer;
6355 +        }
6356 +        @SuppressWarnings("unchecked") public final boolean exec() {
6357 +            final ObjectToInt<? super V> transformer =
6358 +                this.transformer;
6359 +            final IntByIntToInt reducer = this.reducer;
6360 +            if (transformer == null || reducer == null)
6361 +                return abortOnNullFunction();
6362 +            try {
6363 +                final int id = this.basis;
6364 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6365 +                    do {} while (!casPending(c = pending, c+1));
6366 +                    (rights = new MapReduceValuesToIntTask<K,V>
6367 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6368 +                }
6369 +                int r = id;
6370 +                Object v;
6371 +                while ((v = advance()) != null)
6372 +                    r = reducer.apply(r, transformer.apply((V)v));
6373 +                result = r;
6374 +                for (MapReduceValuesToIntTask<K,V> t = this, s;;) {
6375 +                    int c; BulkTask<K,V,?> par;
6376 +                    if ((c = t.pending) == 0) {
6377 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6378 +                            t.result = reducer.apply(t.result, s.result);
6379 +                        }
6380 +                        if ((par = t.parent) == null ||
6381 +                            !(par instanceof MapReduceValuesToIntTask)) {
6382 +                            t.quietlyComplete();
6383 +                            break;
6384 +                        }
6385 +                        t = (MapReduceValuesToIntTask<K,V>)par;
6386 +                    }
6387 +                    else if (t.casPending(c, c - 1))
6388 +                        break;
6389 +                }
6390 +            } catch (Throwable ex) {
6391 +                return tryCompleteComputation(ex);
6392 +            }
6393 +            return false;
6394 +        }
6395 +        public final Integer getRawResult() { return result; }
6396 +    }
6397 +
6398 +    @SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6399 +        extends BulkTask<K,V,Integer> {
6400 +        final ObjectToInt<Map.Entry<K,V>> transformer;
6401 +        final IntByIntToInt reducer;
6402 +        final int basis;
6403 +        int result;
6404 +        MapReduceEntriesToIntTask<K,V> rights, nextRight;
6405 +        MapReduceEntriesToIntTask
6406 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6407 +             MapReduceEntriesToIntTask<K,V> nextRight,
6408 +             ObjectToInt<Map.Entry<K,V>> transformer,
6409 +             int basis,
6410 +             IntByIntToInt reducer) {
6411 +            super(m, p, b); this.nextRight = nextRight;
6412 +            this.transformer = transformer;
6413 +            this.basis = basis; this.reducer = reducer;
6414 +        }
6415 +        @SuppressWarnings("unchecked") public final boolean exec() {
6416 +            final ObjectToInt<Map.Entry<K,V>> transformer =
6417 +                this.transformer;
6418 +            final IntByIntToInt reducer = this.reducer;
6419 +            if (transformer == null || reducer == null)
6420 +                return abortOnNullFunction();
6421 +            try {
6422 +                final int id = this.basis;
6423 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6424 +                    do {} while (!casPending(c = pending, c+1));
6425 +                    (rights = new MapReduceEntriesToIntTask<K,V>
6426 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6427 +                }
6428 +                int r = id;
6429 +                Object v;
6430 +                while ((v = advance()) != null)
6431 +                    r = reducer.apply(r, transformer.apply(entryFor((K)nextKey, (V)v)));
6432 +                result = r;
6433 +                for (MapReduceEntriesToIntTask<K,V> t = this, s;;) {
6434 +                    int c; BulkTask<K,V,?> par;
6435 +                    if ((c = t.pending) == 0) {
6436 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6437 +                            t.result = reducer.apply(t.result, s.result);
6438 +                        }
6439 +                        if ((par = t.parent) == null ||
6440 +                            !(par instanceof MapReduceEntriesToIntTask)) {
6441 +                            t.quietlyComplete();
6442 +                            break;
6443 +                        }
6444 +                        t = (MapReduceEntriesToIntTask<K,V>)par;
6445 +                    }
6446 +                    else if (t.casPending(c, c - 1))
6447 +                        break;
6448 +                }
6449 +            } catch (Throwable ex) {
6450 +                return tryCompleteComputation(ex);
6451 +            }
6452 +            return false;
6453 +        }
6454 +        public final Integer getRawResult() { return result; }
6455 +    }
6456 +
6457 +    @SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6458 +        extends BulkTask<K,V,Integer> {
6459 +        final ObjectByObjectToInt<? super K, ? super V> transformer;
6460 +        final IntByIntToInt reducer;
6461 +        final int basis;
6462 +        int result;
6463 +        MapReduceMappingsToIntTask<K,V> rights, nextRight;
6464 +        MapReduceMappingsToIntTask
6465 +            (ConcurrentHashMapV8<K,V> m, BulkTask<K,V,?> p, int b,
6466 +             MapReduceMappingsToIntTask<K,V> rights,
6467 +             ObjectByObjectToInt<? super K, ? super V> transformer,
6468 +             int basis,
6469 +             IntByIntToInt reducer) {
6470 +            super(m, p, b); this.nextRight = nextRight;
6471 +            this.transformer = transformer;
6472 +            this.basis = basis; this.reducer = reducer;
6473 +        }
6474 +        @SuppressWarnings("unchecked") public final boolean exec() {
6475 +            final ObjectByObjectToInt<? super K, ? super V> transformer =
6476 +                this.transformer;
6477 +            final IntByIntToInt reducer = this.reducer;
6478 +            if (transformer == null || reducer == null)
6479 +                return abortOnNullFunction();
6480 +            try {
6481 +                final int id = this.basis;
6482 +                for (int c, b = batch(); b > 1 && baseIndex != baseLimit;) {
6483 +                    do {} while (!casPending(c = pending, c+1));
6484 +                    (rights = new MapReduceMappingsToIntTask<K,V>
6485 +                     (map, this, b >>>= 1, rights, transformer, id, reducer)).fork();
6486 +                }
6487 +                int r = id;
6488 +                Object v;
6489 +                while ((v = advance()) != null)
6490 +                    r = reducer.apply(r, transformer.apply((K)nextKey, (V)v));
6491 +                result = r;
6492 +                for (MapReduceMappingsToIntTask<K,V> t = this, s;;) {
6493 +                    int c; BulkTask<K,V,?> par;
6494 +                    if ((c = t.pending) == 0) {
6495 +                        for (s = t.rights; s != null; s = t.rights = s.nextRight) {
6496 +                            t.result = reducer.apply(t.result, s.result);
6497 +                        }
6498 +                        if ((par = t.parent) == null ||
6499 +                            !(par instanceof MapReduceMappingsToIntTask)) {
6500 +                            t.quietlyComplete();
6501 +                            break;
6502 +                        }
6503 +                        t = (MapReduceMappingsToIntTask<K,V>)par;
6504 +                    }
6505 +                    else if (t.casPending(c, c - 1))
6506 +                        break;
6507 +                }
6508 +            } catch (Throwable ex) {
6509 +                return tryCompleteComputation(ex);
6510 +            }
6511 +            return false;
6512 +        }
6513 +        public final Integer getRawResult() { return result; }
6514 +    }
6515 +
6516 +
6517      // Unsafe mechanics
6518      private static final sun.misc.Unsafe UNSAFE;
6519      private static final long counterOffset;
6520 <    private static final long loadFactorOffset;
1655 <    private static final long resizingOffset;
6520 >    private static final long sizeCtlOffset;
6521      private static final long ABASE;
6522      private static final int ASHIFT;
6523  
# Line 1663 | Line 6528 | public class ConcurrentHashMapV8<K, V>
6528              Class<?> k = ConcurrentHashMapV8.class;
6529              counterOffset = UNSAFE.objectFieldOffset
6530                  (k.getDeclaredField("counter"));
6531 <            loadFactorOffset = UNSAFE.objectFieldOffset
6532 <                (k.getDeclaredField("loadFactor"));
1668 <            resizingOffset = UNSAFE.objectFieldOffset
1669 <                (k.getDeclaredField("resizing"));
6531 >            sizeCtlOffset = UNSAFE.objectFieldOffset
6532 >                (k.getDeclaredField("sizeCtl"));
6533              Class<?> sc = Node[].class;
6534              ABASE = UNSAFE.arrayBaseOffset(sc);
6535              ss = UNSAFE.arrayIndexScale(sc);
# Line 1705 | Line 6568 | public class ConcurrentHashMapV8<K, V>
6568              }
6569          }
6570      }
1708
6571   }

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