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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.110 by jsr166, Wed Apr 27 14:06:30 2011 UTC vs.
Revision 1.152 by jsr166, Sat Dec 15 21:00:15 2012 UTC

#	Line 5 | Line 5
5		*/
6
7		package java.util.concurrent;
8	<	import java.util.concurrent.locks.*;
9	<	import java.util.*;
8	>	import java.util.concurrent.ForkJoinPool;
9	>	import java.util.concurrent.CountedCompleter;
10	>
11	>	import java.util.Comparator;
12	>	import java.util.Arrays;
13	>	import java.util.Map;
14	>	import java.util.Set;
15	>	import java.util.Collection;
16	>	import java.util.AbstractMap;
17	>	import java.util.AbstractSet;
18	>	import java.util.AbstractCollection;
19	>	import java.util.Hashtable;
20	>	import java.util.HashMap;
21	>	import java.util.Iterator;
22	>	import java.util.Enumeration;
23	>	import java.util.ConcurrentModificationException;
24	>	import java.util.NoSuchElementException;
25	>	import java.util.concurrent.ConcurrentMap;
26	>	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
27	>	import java.util.concurrent.atomic.AtomicInteger;
28	>	import java.util.concurrent.atomic.AtomicReference;
29		import java.io.Serializable;
11	–	import java.io.IOException;
12	–	import java.io.ObjectInputStream;
13	–	import java.io.ObjectOutputStream;
30
31		/**
32		* A hash table supporting full concurrency of retrievals and
33	<	* adjustable expected concurrency for updates. This class obeys the
33	>	* high expected concurrency for updates. This class obeys the
34		* same functional specification as {@link java.util.Hashtable}, and
35		* includes versions of methods corresponding to each method of
36	<	* <tt>Hashtable</tt>. However, even though all operations are
36	>	* {@code Hashtable}. However, even though all operations are
37		* thread-safe, retrieval operations do <em>not</em> entail locking,
38		* and there is <em>not</em> any support for locking the entire table
39		* in a way that prevents all access.  This class is fully
40	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
40	>	* interoperable with {@code Hashtable} in programs that rely on its
41		* thread safety but not on its synchronization details.
42		*
43	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
44	<	* block, so may overlap with update operations (including
45	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
46	<	* of the most recently <em>completed</em> update operations holding
47	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
48	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
49	<	* removal of only some entries.  Similarly, Iterators and
50	<	* Enumerations return elements reflecting the state of the hash table
51	<	* at some point at or since the creation of the iterator/enumeration.
52	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
53	<	* However, iterators are designed to be used by only one thread at a time.
54	<	*
55	<	* <p> The allowed concurrency among update operations is guided by
56	<	* the optional <tt>concurrencyLevel</tt> constructor argument
57	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
58	<	* table is internally partitioned to try to permit the indicated
59	<	* number of concurrent updates without contention. Because placement
60	<	* in hash tables is essentially random, the actual concurrency will
61	<	* vary.  Ideally, you should choose a value to accommodate as many
62	<	* threads as will ever concurrently modify the table. Using a
63	<	* significantly higher value than you need can waste space and time,
64	<	* and a significantly lower value can lead to thread contention. But
65	<	* overestimates and underestimates within an order of magnitude do
66	<	* not usually have much noticeable impact. A value of one is
67	<	* appropriate when it is known that only one thread will modify and
68	<	* all others will only read. Also, resizing this or any other kind of
69	<	* hash table is a relatively slow operation, so, when possible, it is
70	<	* a good idea to provide estimates of expected table sizes in
71	<	* constructors.
43	>	* <p>Retrieval operations (including {@code get}) generally do not
44	>	* block, so may overlap with update operations (including {@code put}
45	>	* and {@code remove}). Retrievals reflect the results of the most
46	>	* recently <em>completed</em> update operations holding upon their
47	>	* onset. (More formally, an update operation for a given key bears a
48	>	* <em>happens-before</em> relation with any (non-null) retrieval for
49	>	* that key reporting the updated value.)  For aggregate operations
50	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
51	>	* reflect insertion or removal of only some entries.  Similarly,
52	>	* Iterators and Enumerations return elements reflecting the state of
53	>	* the hash table at some point at or since the creation of the
54	>	* iterator/enumeration.  They do <em>not</em> throw {@link
55	>	* ConcurrentModificationException}.  However, iterators are designed
56	>	* to be used by only one thread at a time.  Bear in mind that the
57	>	* results of aggregate status methods including {@code size}, {@code
58	>	* isEmpty}, and {@code containsValue} are typically useful only when
59	>	* a map is not undergoing concurrent updates in other threads.
60	>	* Otherwise the results of these methods reflect transient states
61	>	* that may be adequate for monitoring or estimation purposes, but not
62	>	* for program control.
63	>	*
64	>	* <p>The table is dynamically expanded when there are too many
65	>	* collisions (i.e., keys that have distinct hash codes but fall into
66	>	* the same slot modulo the table size), with the expected average
67	>	* effect of maintaining roughly two bins per mapping (corresponding
68	>	* to a 0.75 load factor threshold for resizing). There may be much
69	>	* variance around this average as mappings are added and removed, but
70	>	* overall, this maintains a commonly accepted time/space tradeoff for
71	>	* hash tables.  However, resizing this or any other kind of hash
72	>	* table may be a relatively slow operation. When possible, it is a
73	>	* good idea to provide a size estimate as an optional {@code
74	>	* initialCapacity} constructor argument. An additional optional
75	>	* {@code loadFactor} constructor argument provides a further means of
76	>	* customizing initial table capacity by specifying the table density
77	>	* to be used in calculating the amount of space to allocate for the
78	>	* given number of elements.  Also, for compatibility with previous
79	>	* versions of this class, constructors may optionally specify an
80	>	* expected {@code concurrencyLevel} as an additional hint for
81	>	* internal sizing.  Note that using many keys with exactly the same
82	>	* {@code hashCode()} is a sure way to slow down performance of any
83	>	* hash table.
84	>	*
85	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
86	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
87	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
88	>	* mapped values are (perhaps transiently) not used or all take the
89	>	* same mapping value.
90	>	*
91	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
92	>	* form of histogram or multiset) by using {@link LongAdder} values
93	>	* and initializing via {@link #computeIfAbsent}. For example, to add
94	>	* a count to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you
95	>	* can use {@code freqs.computeIfAbsent(k -> new
96	>	* LongAdder()).increment();}
97		*
98		* <p>This class and its views and iterators implement all of the
99		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
100		* interfaces.
101		*
102	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
103	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
102	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
103	>	* does <em>not</em> allow {@code null} to be used as a key or value.
104	>	*
105	>	* <p>ConcurrentHashMaps support sequential and parallel operations
106	>	* bulk operations. (Parallel forms use the {@link
107	>	* ForkJoinPool#commonPool()}). Tasks that may be used in other
108	>	* contexts are available in class {@link ForkJoinTasks}. These
109	>	* operations are designed to be safely, and often sensibly, applied
110	>	* even with maps that are being concurrently updated by other
111	>	* threads; for example, when computing a snapshot summary of the
112	>	* values in a shared registry.  There are three kinds of operation,
113	>	* each with four forms, accepting functions with Keys, Values,
114	>	* Entries, and (Key, Value) arguments and/or return values. Because
115	>	* the elements of a ConcurrentHashMap are not ordered in any
116	>	* particular way, and may be processed in different orders in
117	>	* different parallel executions, the correctness of supplied
118	>	* functions should not depend on any ordering, or on any other
119	>	* objects or values that may transiently change while computation is
120	>	* in progress; and except for forEach actions, should ideally be
121	>	* side-effect-free.
122	>	*
123	>	* <ul>
124	>	* <li> forEach: Perform a given action on each element.
125	>	* A variant form applies a given transformation on each element
126	>	* before performing the action.</li>
127	>	*
128	>	* <li> search: Return the first available non-null result of
129	>	* applying a given function on each element; skipping further
130	>	* search when a result is found.</li>
131	>	*
132	>	* <li> reduce: Accumulate each element.  The supplied reduction
133	>	* function cannot rely on ordering (more formally, it should be
134	>	* both associative and commutative).  There are five variants:
135	>	*
136	>	* <ul>
137	>	*
138	>	* <li> Plain reductions. (There is not a form of this method for
139	>	* (key, value) function arguments since there is no corresponding
140	>	* return type.)</li>
141	>	*
142	>	* <li> Mapped reductions that accumulate the results of a given
143	>	* function applied to each element.</li>
144	>	*
145	>	* <li> Reductions to scalar doubles, longs, and ints, using a
146	>	* given basis value.</li>
147	>	*
148	>	* </li>
149	>	* </ul>
150	>	* </ul>
151	>	*
152	>	* <p>The concurrency properties of bulk operations follow
153	>	* from those of ConcurrentHashMap: Any non-null result returned
154	>	* from {@code get(key)} and related access methods bears a
155	>	* happens-before relation with the associated insertion or
156	>	* update.  The result of any bulk operation reflects the
157	>	* composition of these per-element relations (but is not
158	>	* necessarily atomic with respect to the map as a whole unless it
159	>	* is somehow known to be quiescent).  Conversely, because keys
160	>	* and values in the map are never null, null serves as a reliable
161	>	* atomic indicator of the current lack of any result.  To
162	>	* maintain this property, null serves as an implicit basis for
163	>	* all non-scalar reduction operations. For the double, long, and
164	>	* int versions, the basis should be one that, when combined with
165	>	* any other value, returns that other value (more formally, it
166	>	* should be the identity element for the reduction). Most common
167	>	* reductions have these properties; for example, computing a sum
168	>	* with basis 0 or a minimum with basis MAX_VALUE.
169	>	*
170	>	* <p>Search and transformation functions provided as arguments
171	>	* should similarly return null to indicate the lack of any result
172	>	* (in which case it is not used). In the case of mapped
173	>	* reductions, this also enables transformations to serve as
174	>	* filters, returning null (or, in the case of primitive
175	>	* specializations, the identity basis) if the element should not
176	>	* be combined. You can create compound transformations and
177	>	* filterings by composing them yourself under this "null means
178	>	* there is nothing there now" rule before using them in search or
179	>	* reduce operations.
180	>	*
181	>	* <p>Methods accepting and/or returning Entry arguments maintain
182	>	* key-value associations. They may be useful for example when
183	>	* finding the key for the greatest value. Note that "plain" Entry
184	>	* arguments can be supplied using {@code new
185	>	* AbstractMap.SimpleEntry(k,v)}.
186	>	*
187	>	* <p>Bulk operations may complete abruptly, throwing an
188	>	* exception encountered in the application of a supplied
189	>	* function. Bear in mind when handling such exceptions that other
190	>	* concurrently executing functions could also have thrown
191	>	* exceptions, or would have done so if the first exception had
192	>	* not occurred.
193	>	*
194	>	* <p>Speedups for parallel compared to sequential forms are common
195	>	* but not guaranteed.  Parallel operations involving brief functions
196	>	* on small maps may execute more slowly than sequential forms if the
197	>	* underlying work to parallelize the computation is more expensive
198	>	* than the computation itself.  Similarly, parallelization may not
199	>	* lead to much actual parallelism if all processors are busy
200	>	* performing unrelated tasks.
201	>	*
202	>	* <p>All arguments to all task methods must be non-null.
203	>	*
204	>	* <p><em>jsr166e note: During transition, this class
205	>	* uses nested functional interfaces with different names but the
206	>	* same forms as those expected for JDK8.</em>
207		*
208		* <p>This class is a member of the
209		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 70 | Line 214 | import java.io.ObjectOutputStream;
214		* @param <K> the type of keys maintained by this map
215		* @param <V> the type of mapped values
216		*/
217	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
218	<	implements ConcurrentMap<K, V>, Serializable {
217	>	public class ConcurrentHashMap<K, V>
218	>	implements ConcurrentMap<K, V>, Serializable {
219		private static final long serialVersionUID = 7249069246763182397L;
220
221	+	/**
222	+	* A partitionable iterator. A Spliterator can be traversed
223	+	* directly, but can also be partitioned (before traversal) by
224	+	* creating another Spliterator that covers a non-overlapping
225	+	* portion of the elements, and so may be amenable to parallel
226	+	* execution.
227	+	*
228	+	* <p>This interface exports a subset of expected JDK8
229	+	* functionality.
230	+	*
231	+	* <p>Sample usage: Here is one (of the several) ways to compute
232	+	* the sum of the values held in a map using the ForkJoin
233	+	* framework. As illustrated here, Spliterators are well suited to
234	+	* designs in which a task repeatedly splits off half its work
235	+	* into forked subtasks until small enough to process directly,
236	+	* and then joins these subtasks. Variants of this style can also
237	+	* be used in completion-based designs.
238	+	*
239	+	* <pre>
240	+	* {@code ConcurrentHashMap<String, Long> m = ...
241	+	* // split as if have 8 * parallelism, for load balance
242	+	* int n = m.size();
243	+	* int p = aForkJoinPool.getParallelism() * 8;
244	+	* int split = (n < p)? n : p;
245	+	* long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
246	+	* // ...
247	+	* static class SumValues extends RecursiveTask<Long> {
248	+	*   final Spliterator<Long> s;
249	+	*   final int split;             // split while > 1
250	+	*   final SumValues nextJoin;    // records forked subtasks to join
251	+	*   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
252	+	*     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
253	+	*   }
254	+	*   public Long compute() {
255	+	*     long sum = 0;
256	+	*     SumValues subtasks = null; // fork subtasks
257	+	*     for (int s = split >>> 1; s > 0; s >>>= 1)
258	+	*       (subtasks = new SumValues(s.split(), s, subtasks)).fork();
259	+	*     while (s.hasNext())        // directly process remaining elements
260	+	*       sum += s.next();
261	+	*     for (SumValues t = subtasks; t != null; t = t.nextJoin)
262	+	*       sum += t.join();         // collect subtask results
263	+	*     return sum;
264	+	*   }
265	+	* }
266	+	* }</pre>
267	+	*/
268	+	public static interface Spliterator<T> extends Iterator<T> {
269	+	/**
270	+	* Returns a Spliterator covering approximately half of the
271	+	* elements, guaranteed not to overlap with those subsequently
272	+	* returned by this Spliterator.  After invoking this method,
273	+	* the current Spliterator will <em>not</em> produce any of
274	+	* the elements of the returned Spliterator, but the two
275	+	* Spliterators together will produce all of the elements that
276	+	* would have been produced by this Spliterator had this
277	+	* method not been called. The exact number of elements
278	+	* produced by the returned Spliterator is not guaranteed, and
279	+	* may be zero (i.e., with {@code hasNext()} reporting {@code
280	+	* false}) if this Spliterator cannot be further split.
281	+	*
282	+	* @return a Spliterator covering approximately half of the
283	+	* elements
284	+	* @throws IllegalStateException if this Spliterator has
285	+	* already commenced traversing elements
286	+	*/
287	+	Spliterator<T> split();
288	+	}
289	+
290		/*
291	<	* The basic strategy is to subdivide the table among Segments,
292	<	* each of which itself is a concurrently readable hash table.  To
293	<	* reduce footprint, all but one segments are constructed only
294	<	* when first needed (see ensureSegment). To maintain visibility
295	<	* in the presence of lazy construction, accesses to segments as
296	<	* well as elements of segment's table must use volatile access,
297	<	* which is done via Unsafe within methods segmentAt etc
298	<	* below. These provide the functionality of AtomicReferenceArrays
299	<	* but reduce the levels of indirection. Additionally,
300	<	* volatile-writes of table elements and entry "next" fields
301	<	* within locked operations use the cheaper "lazySet" forms of
302	<	* writes (via putOrderedObject) because these writes are always
303	<	* followed by lock releases that maintain sequential consistency
304	<	* of table updates.
305	<	*
306	<	* Historical note: The previous version of this class relied
307	<	* heavily on "final" fields, which avoided some volatile reads at
308	<	* the expense of a large initial footprint.  Some remnants of
309	<	* that design (including forced construction of segment 0) exist
310	<	* to ensure serialization compatibility.
291	>	* Overview:
292	>	*
293	>	* The primary design goal of this hash table is to maintain
294	>	* concurrent readability (typically method get(), but also
295	>	* iterators and related methods) while minimizing update
296	>	* contention. Secondary goals are to keep space consumption about
297	>	* the same or better than java.util.HashMap, and to support high
298	>	* initial insertion rates on an empty table by many threads.
299	>	*
300	>	* Each key-value mapping is held in a Node.  Because Node key
301	>	* fields can contain special values, they are defined using plain
302	>	* Object types (not type "K"). This leads to a lot of explicit
303	>	* casting (and many explicit warning suppressions to tell
304	>	* compilers not to complain about it). It also allows some of the
305	>	* public methods to be factored into a smaller number of internal
306	>	* methods (although sadly not so for the five variants of
307	>	* put-related operations). The validation-based approach
308	>	* explained below leads to a lot of code sprawl because
309	>	* retry-control precludes factoring into smaller methods.
310	>	*
311	>	* The table is lazily initialized to a power-of-two size upon the
312	>	* first insertion.  Each bin in the table normally contains a
313	>	* list of Nodes (most often, the list has only zero or one Node).
314	>	* Table accesses require volatile/atomic reads, writes, and
315	>	* CASes.  Because there is no other way to arrange this without
316	>	* adding further indirections, we use intrinsics
317	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
318	>	* are always accurately traversable under volatile reads, so long
319	>	* as lookups check hash code and non-nullness of value before
320	>	* checking key equality.
321	>	*
322	>	* We use the top (sign) bit of Node hash fields for control
323	>	* purposes -- it is available anyway because of addressing
324	>	* constraints.  Nodes with negative hash fields are forwarding
325	>	* nodes to either TreeBins or resized tables.  The lower 31 bits
326	>	* of each normal Node's hash field contain a transformation of
327	>	* the key's hash code.
328	>	*
329	>	* Insertion (via put or its variants) of the first node in an
330	>	* empty bin is performed by just CASing it to the bin.  This is
331	>	* by far the most common case for put operations under most
332	>	* key/hash distributions.  Other update operations (insert,
333	>	* delete, and replace) require locks.  We do not want to waste
334	>	* the space required to associate a distinct lock object with
335	>	* each bin, so instead use the first node of a bin list itself as
336	>	* a lock. Locking support for these locks relies on builtin
337	>	* "synchronized" monitors.
338	>	*
339	>	* Using the first node of a list as a lock does not by itself
340	>	* suffice though: When a node is locked, any update must first
341	>	* validate that it is still the first node after locking it, and
342	>	* retry if not. Because new nodes are always appended to lists,
343	>	* once a node is first in a bin, it remains first until deleted
344	>	* or the bin becomes invalidated (upon resizing).  However,
345	>	* operations that only conditionally update may inspect nodes
346	>	* until the point of update. This is a converse of sorts to the
347	>	* lazy locking technique described by Herlihy & Shavit.
348	>	*
349	>	* The main disadvantage of per-bin locks is that other update
350	>	* operations on other nodes in a bin list protected by the same
351	>	* lock can stall, for example when user equals() or mapping
352	>	* functions take a long time.  However, statistically, under
353	>	* random hash codes, this is not a common problem.  Ideally, the
354	>	* frequency of nodes in bins follows a Poisson distribution
355	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
356	>	* parameter of about 0.5 on average, given the resizing threshold
357	>	* of 0.75, although with a large variance because of resizing
358	>	* granularity. Ignoring variance, the expected occurrences of
359	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
360	>	* first values are:
361	>	*
362	>	* 0:    0.60653066
363	>	* 1:    0.30326533
364	>	* 2:    0.07581633
365	>	* 3:    0.01263606
366	>	* 4:    0.00157952
367	>	* 5:    0.00015795
368	>	* 6:    0.00001316
369	>	* 7:    0.00000094
370	>	* 8:    0.00000006
371	>	* more: less than 1 in ten million
372	>	*
373	>	* Lock contention probability for two threads accessing distinct
374	>	* elements is roughly 1 / (8 * #elements) under random hashes.
375	>	*
376	>	* Actual hash code distributions encountered in practice
377	>	* sometimes deviate significantly from uniform randomness.  This
378	>	* includes the case when N > (1<<30), so some keys MUST collide.
379	>	* Similarly for dumb or hostile usages in which multiple keys are
380	>	* designed to have identical hash codes. Also, although we guard
381	>	* against the worst effects of this (see method spread), sets of
382	>	* hashes may differ only in bits that do not impact their bin
383	>	* index for a given power-of-two mask.  So we use a secondary
384	>	* strategy that applies when the number of nodes in a bin exceeds
385	>	* a threshold, and at least one of the keys implements
386	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
387	>	* (a specialized form of red-black trees), bounding search time
388	>	* to O(log N).  Each search step in a TreeBin is around twice as
389	>	* slow as in a regular list, but given that N cannot exceed
390	>	* (1<<64) (before running out of addresses) this bounds search
391	>	* steps, lock hold times, etc, to reasonable constants (roughly
392	>	* 100 nodes inspected per operation worst case) so long as keys
393	>	* are Comparable (which is very common -- String, Long, etc).
394	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
395	>	* traversal pointers as regular nodes, so can be traversed in
396	>	* iterators in the same way.
397	>	*
398	>	* The table is resized when occupancy exceeds a percentage
399	>	* threshold (nominally, 0.75, but see below).  Any thread
400	>	* noticing an overfull bin may assist in resizing after the
401	>	* initiating thread allocates and sets up the replacement
402	>	* array. However, rather than stalling, these other threads may
403	>	* proceed with insertions etc.  The use of TreeBins shields us
404	>	* from the worst case effects of overfilling while resizes are in
405	>	* progress.  Resizing proceeds by transferring bins, one by one,
406	>	* from the table to the next table. To enable concurrency, the
407	>	* next table must be (incrementally) prefilled with place-holders
408	>	* serving as reverse forwarders to the old table.  Because we are
409	>	* using power-of-two expansion, the elements from each bin must
410	>	* either stay at same index, or move with a power of two
411	>	* offset. We eliminate unnecessary node creation by catching
412	>	* cases where old nodes can be reused because their next fields
413	>	* won't change.  On average, only about one-sixth of them need
414	>	* cloning when a table doubles. The nodes they replace will be
415	>	* garbage collectable as soon as they are no longer referenced by
416	>	* any reader thread that may be in the midst of concurrently
417	>	* traversing table.  Upon transfer, the old table bin contains
418	>	* only a special forwarding node (with hash field "MOVED") that
419	>	* contains the next table as its key. On encountering a
420	>	* forwarding node, access and update operations restart, using
421	>	* the new table.
422	>	*
423	>	* Each bin transfer requires its bin lock, which can stall
424	>	* waiting for locks while resizing. However, because other
425	>	* threads can join in and help resize rather than contend for
426	>	* locks, average aggregate waits become shorter as resizing
427	>	* progresses.  The transfer operation must also ensure that all
428	>	* accessible bins in both the old and new table are usable by any
429	>	* traversal.  This is arranged by proceeding from the last bin
430	>	* (table.length - 1) up towards the first.  Upon seeing a
431	>	* forwarding node, traversals (see class Traverser) arrange to
432	>	* move to the new table without revisiting nodes.  However, to
433	>	* ensure that no intervening nodes are skipped, bin splitting can
434	>	* only begin after the associated reverse-forwarders are in
435	>	* place.
436	>	*
437	>	* The traversal scheme also applies to partial traversals of
438	>	* ranges of bins (via an alternate Traverser constructor)
439	>	* to support partitioned aggregate operations.  Also, read-only
440	>	* operations give up if ever forwarded to a null table, which
441	>	* provides support for shutdown-style clearing, which is also not
442	>	* currently implemented.
443	>	*
444	>	* Lazy table initialization minimizes footprint until first use,
445	>	* and also avoids resizings when the first operation is from a
446	>	* putAll, constructor with map argument, or deserialization.
447	>	* These cases attempt to override the initial capacity settings,
448	>	* but harmlessly fail to take effect in cases of races.
449	>	*
450	>	* The element count is maintained using a specialization of
451	>	* LongAdder. We need to incorporate a specialization rather than
452	>	* just use a LongAdder in order to access implicit
453	>	* contention-sensing that leads to creation of multiple
454	>	* CounterCells.  The counter mechanics avoid contention on
455	>	* updates but can encounter cache thrashing if read too
456	>	* frequently during concurrent access. To avoid reading so often,
457	>	* resizing under contention is attempted only upon adding to a
458	>	* bin already holding two or more nodes. Under uniform hash
459	>	* distributions, the probability of this occurring at threshold
460	>	* is around 13%, meaning that only about 1 in 8 puts check
461	>	* threshold (and after resizing, many fewer do so). The bulk
462	>	* putAll operation further reduces contention by only committing
463	>	* count updates upon these size checks.
464	>	*
465	>	* Maintaining API and serialization compatibility with previous
466	>	* versions of this class introduces several oddities. Mainly: We
467	>	* leave untouched but unused constructor arguments refering to
468	>	* concurrencyLevel. We accept a loadFactor constructor argument,
469	>	* but apply it only to initial table capacity (which is the only
470	>	* time that we can guarantee to honor it.) We also declare an
471	>	* unused "Segment" class that is instantiated in minimal form
472	>	* only when serializing.
473		*/
474
475		/* ---------------- Constants -------------- */
476
477		/**
478	<	* The default initial capacity for this table,
479	<	* used when not otherwise specified in a constructor.
478	>	* The largest possible table capacity.  This value must be
479	>	* exactly 1<<30 to stay within Java array allocation and indexing
480	>	* bounds for power of two table sizes, and is further required
481	>	* because the top two bits of 32bit hash fields are used for
482	>	* control purposes.
483		*/
484	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
484	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
485
486		/**
487	<	* The default load factor for this table, used when not
488	<	* otherwise specified in a constructor.
487	>	* The default initial table capacity.  Must be a power of 2
488	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
489		*/
490	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
490	>	private static final int DEFAULT_CAPACITY = 16;
491
492		/**
493	<	* The default concurrency level for this table, used when not
494	<	* otherwise specified in a constructor.
493	>	* The largest possible (non-power of two) array size.
494	>	* Needed by toArray and related methods.
495		*/
496	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
496	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
497
498		/**
499	<	* The maximum capacity, used if a higher value is implicitly
500	<	* specified by either of the constructors with arguments.  MUST
123	<	* be a power of two <= 1<<30 to ensure that entries are indexable
124	<	* using ints.
499	>	* The default concurrency level for this table. Unused but
500	>	* defined for compatibility with previous versions of this class.
501		*/
502	<	static final int MAXIMUM_CAPACITY = 1 << 30;
502	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
503
504		/**
505	<	* The minimum capacity for per-segment tables.  Must be a power
506	<	* of two, at least two to avoid immediate resizing on next use
507	<	* after lazy construction.
505	>	* The load factor for this table. Overrides of this value in
506	>	* constructors affect only the initial table capacity.  The
507	>	* actual floating point value isn't normally used -- it is
508	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
509	>	* the associated resizing threshold.
510		*/
511	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
511	>	private static final float LOAD_FACTOR = 0.75f;
512
513		/**
514	<	* The maximum number of segments to allow; used to bound
515	<	* constructor arguments. Must be power of two less than 1 << 24.
514	>	* The bin count threshold for using a tree rather than list for a
515	>	* bin.  The value reflects the approximate break-even point for
516	>	* using tree-based operations.
517		*/
518	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
518	>	private static final int TREE_THRESHOLD = 8;
519
520		/**
521	<	* Number of unsynchronized retries in size and containsValue
522	<	* methods before resorting to locking. This is used to avoid
523	<	* unbounded retries if tables undergo continuous modification
524	<	* which would make it impossible to obtain an accurate result.
521	>	* Minimum number of rebinnings per transfer step. Ranges are
522	>	* subdivided to allow multiple resizer threads.  This value
523	>	* serves as a lower bound to avoid resizers encountering
524	>	* excessive memory contention.  The value should be at least
525	>	* DEFAULT_CAPACITY.
526		*/
527	<	static final int RETRIES_BEFORE_LOCK = 2;
527	>	private static final int MIN_TRANSFER_STRIDE = 16;
528	>
529	>	/*
530	>	* Encodings for Node hash fields. See above for explanation.
531	>	*/
532	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
533	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
534	>
535	>	/** Number of CPUS, to place bounds on some sizings */
536	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
537	>
538	>	/* ---------------- Counters -------------- */
539	>
540	>	// Adapted from LongAdder and Striped64.
541	>	// See their internal docs for explanation.
542	>
543	>	// A padded cell for distributing counts
544	>	static final class CounterCell {
545	>	volatile long p0, p1, p2, p3, p4, p5, p6;
546	>	volatile long value;
547	>	volatile long q0, q1, q2, q3, q4, q5, q6;
548	>	CounterCell(long x) { value = x; }
549	>	}
550	>
551	>	/**
552	>	* Holder for the thread-local hash code determining which
553	>	* CounterCell to use. The code is initialized via the
554	>	* counterHashCodeGenerator, but may be moved upon collisions.
555	>	*/
556	>	static final class CounterHashCode {
557	>	int code;
558	>	}
559	>
560	>	/**
561	>	* Generates initial value for per-thread CounterHashCodes
562	>	*/
563	>	static final AtomicInteger counterHashCodeGenerator = new AtomicInteger();
564	>
565	>	/**
566	>	* Increment for counterHashCodeGenerator. See class ThreadLocal
567	>	* for explanation.
568	>	*/
569	>	static final int SEED_INCREMENT = 0x61c88647;
570	>
571	>	/**
572	>	* Per-thread counter hash codes. Shared across all instances
573	>	*/
574	>	static final ThreadLocal<CounterHashCode> threadCounterHashCode =
575	>	new ThreadLocal<CounterHashCode>();
576
577		/* ---------------- Fields -------------- */
578
579		/**
580	<	* Mask value for indexing into segments. The upper bits of a
581	<	* key's hash code are used to choose the segment.
580	>	* The array of bins. Lazily initialized upon first insertion.
581	>	* Size is always a power of two. Accessed directly by iterators.
582		*/
583	<	final int segmentMask;
583	>	transient volatile Node<V>[] table;
584
585		/**
586	<	* Shift value for indexing within segments.
586	>	* The next table to use; non-null only while resizing.
587		*/
588	<	final int segmentShift;
588	>	private transient volatile Node<V>[] nextTable;
589
590		/**
591	<	* The segments, each of which is a specialized hash table.
591	>	* Base counter value, used mainly when there is no contention,
592	>	* but also as a fallback during table initialization
593	>	* races. Updated via CAS.
594		*/
595	<	final Segment<K,V>[] segments;
595	>	private transient volatile long baseCount;
596	>
597	>	/**
598	>	* Table initialization and resizing control.  When negative, the
599	>	* table is being initialized or resized: -1 for initialization,
600	>	* else -(1 + the number of active resizing threads).  Otherwise,
601	>	* when table is null, holds the initial table size to use upon
602	>	* creation, or 0 for default. After initialization, holds the
603	>	* next element count value upon which to resize the table.
604	>	*/
605	>	private transient volatile int sizeCtl;
606	>
607	>	/**
608	>	* The next table index (plus one) to split while resizing.
609	>	*/
610	>	private transient volatile int transferIndex;
611	>
612	>	/**
613	>	* The least available table index to split while resizing.
614	>	*/
615	>	private transient volatile int transferOrigin;
616	>
617	>	/**
618	>	* Spinlock (locked via CAS) used when resizing and/or creating Cells.
619	>	*/
620	>	private transient volatile int counterBusy;
621	>
622	>	/**
623	>	* Table of counter cells. When non-null, size is a power of 2.
624	>	*/
625	>	private transient volatile CounterCell[] counterCells;
626	>
627	>	// views
628	>	private transient KeySetView<K,V> keySet;
629	>	private transient ValuesView<K,V> values;
630	>	private transient EntrySetView<K,V> entrySet;
631	>
632	>	/** For serialization compatibility. Null unless serialized; see below */
633	>	private Segment<K,V>[] segments;
634	>
635	>	/* ---------------- Table element access -------------- */
636	>
637	>	/*
638	>	* Volatile access methods are used for table elements as well as
639	>	* elements of in-progress next table while resizing.  Uses are
640	>	* null checked by callers, and implicitly bounds-checked, relying
641	>	* on the invariants that tab arrays have non-zero size, and all
642	>	* indices are masked with (tab.length - 1) which is never
643	>	* negative and always less than length. Note that, to be correct
644	>	* wrt arbitrary concurrency errors by users, bounds checks must
645	>	* operate on local variables, which accounts for some odd-looking
646	>	* inline assignments below.
647	>	*/
648	>
649	>	@SuppressWarnings("unchecked") static final <V> Node<V> tabAt
650	>	(Node<V>[] tab, int i) { // used by Traverser
651	>	return (Node<V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
652	>	}
653	>
654	>	private static final <V> boolean casTabAt
655	>	(Node<V>[] tab, int i, Node<V> c, Node<V> v) {
656	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
657	>	}
658	>
659	>	private static final <V> void setTabAt
660	>	(Node<V>[] tab, int i, Node<V> v) {
661	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
662	>	}
663
664	<	transient Set<K> keySet;
168	<	transient Set<Map.Entry<K,V>> entrySet;
169	<	transient Collection<V> values;
664	>	/* ---------------- Nodes -------------- */
665
666		/**
667	<	* ConcurrentHashMap list entry. Note that this is never exported
668	<	* out as a user-visible Map.Entry.
667	>	* Key-value entry. Note that this is never exported out as a
668	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
669	>	* field of MOVED are special, and do not contain user keys or
670	>	* values.  Otherwise, keys are never null, and null val fields
671	>	* indicate that a node is in the process of being deleted or
672	>	* created. For purposes of read-only access, a key may be read
673	>	* before a val, but can only be used after checking val to be
674	>	* non-null.
675		*/
676	<	static final class HashEntry<K,V> {
676	>	static class Node<V> {
677		final int hash;
678	<	final K key;
679	<	volatile V value;
680	<	volatile HashEntry<K,V> next;
678	>	final Object key;
679	>	volatile V val;
680	>	volatile Node<V> next;
681
682	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
682	>	Node(int hash, Object key, V val, Node<V> next) {
683		this.hash = hash;
684		this.key = key;
685	<	this.value = value;
685	>	this.val = val;
686		this.next = next;
687		}
688	+	}
689
690	<	/**
189	<	* Sets next field with volatile write semantics.  (See above
190	<	* about use of putOrderedObject.)
191	<	*/
192	<	final void setNext(HashEntry<K,V> n) {
193	<	UNSAFE.putOrderedObject(this, nextOffset, n);
194	<	}
690	>	/* ---------------- TreeBins -------------- */
691
692	<	// Unsafe mechanics
693	<	static final sun.misc.Unsafe UNSAFE;
694	<	static final long nextOffset;
695	<	static {
696	<	try {
697	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
698	<	Class k = HashEntry.class;
699	<	nextOffset = UNSAFE.objectFieldOffset
700	<	(k.getDeclaredField("next"));
701	<	} catch (Exception e) {
702	<	throw new Error(e);
703	<	}
692	>	/**
693	>	* Nodes for use in TreeBins
694	>	*/
695	>	static final class TreeNode<V> extends Node<V> {
696	>	TreeNode<V> parent;  // red-black tree links
697	>	TreeNode<V> left;
698	>	TreeNode<V> right;
699	>	TreeNode<V> prev;    // needed to unlink next upon deletion
700	>	boolean red;
701	>
702	>	TreeNode(int hash, Object key, V val, Node<V> next, TreeNode<V> parent) {
703	>	super(hash, key, val, next);
704	>	this.parent = parent;
705		}
706		}
707
708		/**
709	<	* Gets the ith element of given table (if nonnull) with volatile
710	<	* read semantics. Note: This is manually integrated into a few
711	<	* performance-sensitive methods to reduce call overhead.
712	<	*/
713	<	@SuppressWarnings("unchecked")
714	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
715	<	return (tab == null) ? null :
716	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
717	<	(tab, ((long)i << TSHIFT) + TBASE);
718	<	}
719	<
720	<	/**
721	<	* Sets the ith element of given table, with volatile write
722	<	* semantics. (See above about use of putOrderedObject.)
723	<	*/
724	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
725	<	HashEntry<K,V> e) {
726	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
727	<	}
728	<
729	<	/**
730	<	* Applies a supplemental hash function to a given hashCode, which
731	<	* defends against poor quality hash functions.  This is critical
732	<	* because ConcurrentHashMap uses power-of-two length hash tables,
733	<	* that otherwise encounter collisions for hashCodes that do not
734	<	* differ in lower or upper bits.
735	<	*/
736	<	private static int hash(int h) {
737	<	// Spread bits to regularize both segment and index locations,
738	<	// using variant of single-word Wang/Jenkins hash.
739	<	h += (h <<  15) ^ 0xffffcd7d;
740	<	h ^= (h >>> 10);
741	<	h += (h <<   3);
742	<	h ^= (h >>>  6);
743	<	h += (h <<   2) + (h << 14);
744	<	return h ^ (h >>> 16);
745	<	}
746	<
747	<	/**
748	<	* Segments are specialized versions of hash tables.  This
749	<	* subclasses from ReentrantLock opportunistically, just to
750	<	* simplify some locking and avoid separate construction.
751	<	*/
255	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
256	<	/*
257	<	* Segments maintain a table of entry lists that are always
258	<	* kept in a consistent state, so can be read (via volatile
259	<	* reads of segments and tables) without locking.  This
260	<	* requires replicating nodes when necessary during table
261	<	* resizing, so the old lists can be traversed by readers
262	<	* still using old version of table.
263	<	*
264	<	* This class defines only mutative methods requiring locking.
265	<	* Except as noted, the methods of this class perform the
266	<	* per-segment versions of ConcurrentHashMap methods.  (Other
267	<	* methods are integrated directly into ConcurrentHashMap
268	<	* methods.) These mutative methods use a form of controlled
269	<	* spinning on contention via methods scanAndLock and
270	<	* scanAndLockForPut. These intersperse tryLocks with
271	<	* traversals to locate nodes.  The main benefit is to absorb
272	<	* cache misses (which are very common for hash tables) while
273	<	* obtaining locks so that traversal is faster once
274	<	* acquired. We do not actually use the found nodes since they
275	<	* must be re-acquired under lock anyway to ensure sequential
276	<	* consistency of updates (and in any case may be undetectably
277	<	* stale), but they will normally be much faster to re-locate.
278	<	* Also, scanAndLockForPut speculatively creates a fresh node
279	<	* to use in put if no node is found.
280	<	*/
281	<
709	>	* A specialized form of red-black tree for use in bins
710	>	* whose size exceeds a threshold.
711	>	*
712	>	* TreeBins use a special form of comparison for search and
713	>	* related operations (which is the main reason we cannot use
714	>	* existing collections such as TreeMaps). TreeBins contain
715	>	* Comparable elements, but may contain others, as well as
716	>	* elements that are Comparable but not necessarily Comparable<T>
717	>	* for the same T, so we cannot invoke compareTo among them. To
718	>	* handle this, the tree is ordered primarily by hash value, then
719	>	* by getClass().getName() order, and then by Comparator order
720	>	* among elements of the same class.  On lookup at a node, if
721	>	* elements are not comparable or compare as 0, both left and
722	>	* right children may need to be searched in the case of tied hash
723	>	* values. (This corresponds to the full list search that would be
724	>	* necessary if all elements were non-Comparable and had tied
725	>	* hashes.)  The red-black balancing code is updated from
726	>	* pre-jdk-collections
727	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
728	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
729	>	* Algorithms" (CLR).
730	>	*
731	>	* TreeBins also maintain a separate locking discipline than
732	>	* regular bins. Because they are forwarded via special MOVED
733	>	* nodes at bin heads (which can never change once established),
734	>	* we cannot use those nodes as locks. Instead, TreeBin
735	>	* extends AbstractQueuedSynchronizer to support a simple form of
736	>	* read-write lock. For update operations and table validation,
737	>	* the exclusive form of lock behaves in the same way as bin-head
738	>	* locks. However, lookups use shared read-lock mechanics to allow
739	>	* multiple readers in the absence of writers.  Additionally,
740	>	* these lookups do not ever block: While the lock is not
741	>	* available, they proceed along the slow traversal path (via
742	>	* next-pointers) until the lock becomes available or the list is
743	>	* exhausted, whichever comes first. (These cases are not fast,
744	>	* but maximize aggregate expected throughput.)  The AQS mechanics
745	>	* for doing this are straightforward.  The lock state is held as
746	>	* AQS getState().  Read counts are negative; the write count (1)
747	>	* is positive.  There are no signalling preferences among readers
748	>	* and writers. Since we don't need to export full Lock API, we
749	>	* just override the minimal AQS methods and use them directly.
750	>	*/
751	>	static final class TreeBin<V> extends AbstractQueuedSynchronizer {
752		private static final long serialVersionUID = 2249069246763182397L;
753	+	transient TreeNode<V> root;  // root of tree
754	+	transient TreeNode<V> first; // head of next-pointer list
755
756	<	/**
757	<	* The maximum number of times to tryLock in a prescan before
758	<	* possibly blocking on acquire in preparation for a locked
759	<	* segment operation. On multiprocessors, using a bounded
760	<	* number of retries maintains cache acquired while locating
761	<	* nodes.
762	<	*/
763	<	static final int MAX_SCAN_RETRIES =
764	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
756	>	/* AQS overrides */
757	>	public final boolean isHeldExclusively() { return getState() > 0; }
758	>	public final boolean tryAcquire(int ignore) {
759	>	if (compareAndSetState(0, 1)) {
760	>	setExclusiveOwnerThread(Thread.currentThread());
761	>	return true;
762	>	}
763	>	return false;
764	>	}
765	>	public final boolean tryRelease(int ignore) {
766	>	setExclusiveOwnerThread(null);
767	>	setState(0);
768	>	return true;
769	>	}
770	>	public final int tryAcquireShared(int ignore) {
771	>	for (int c;;) {
772	>	if ((c = getState()) > 0)
773	>	return -1;
774	>	if (compareAndSetState(c, c -1))
775	>	return 1;
776	>	}
777	>	}
778	>	public final boolean tryReleaseShared(int ignore) {
779	>	int c;
780	>	do {} while (!compareAndSetState(c = getState(), c + 1));
781	>	return c == -1;
782	>	}
783	>
784	>	/** From CLR */
785	>	private void rotateLeft(TreeNode<V> p) {
786	>	if (p != null) {
787	>	TreeNode<V> r = p.right, pp, rl;
788	>	if ((rl = p.right = r.left) != null)
789	>	rl.parent = p;
790	>	if ((pp = r.parent = p.parent) == null)
791	>	root = r;
792	>	else if (pp.left == p)
793	>	pp.left = r;
794	>	else
795	>	pp.right = r;
796	>	r.left = p;
797	>	p.parent = r;
798	>	}
799	>	}
800
801	<	/**
802	<	* The per-segment table. Elements are accessed via
803	<	* entryAt/setEntryAt providing volatile semantics.
804	<	*/
805	<	transient volatile HashEntry<K,V>[] table;
801	>	/** From CLR */
802	>	private void rotateRight(TreeNode<V> p) {
803	>	if (p != null) {
804	>	TreeNode<V> l = p.left, pp, lr;
805	>	if ((lr = p.left = l.right) != null)
806	>	lr.parent = p;
807	>	if ((pp = l.parent = p.parent) == null)
808	>	root = l;
809	>	else if (pp.right == p)
810	>	pp.right = l;
811	>	else
812	>	pp.left = l;
813	>	l.right = p;
814	>	p.parent = l;
815	>	}
816	>	}
817
818		/**
819	<	* The number of elements. Accessed only either within locks
820	<	* or among other volatile reads that maintain visibility.
819	>	* Returns the TreeNode (or null if not found) for the given key
820	>	* starting at given root.
821		*/
822	<	transient int count;
822	>	@SuppressWarnings("unchecked") final TreeNode<V> getTreeNode
823	>	(int h, Object k, TreeNode<V> p) {
824	>	Class<?> c = k.getClass();
825	>	while (p != null) {
826	>	int dir, ph;  Object pk; Class<?> pc;
827	>	if ((ph = p.hash) == h) {
828	>	if ((pk = p.key) == k || k.equals(pk))
829	>	return p;
830	>	if (c != (pc = pk.getClass()) ||
831	>	!(k instanceof Comparable) ||
832	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
833	>	if ((dir = (c == pc) ? 0 :
834	>	c.getName().compareTo(pc.getName())) == 0) {
835	>	TreeNode<V> r = null, pl, pr; // check both sides
836	>	if ((pr = p.right) != null && h >= pr.hash &&
837	>	(r = getTreeNode(h, k, pr)) != null)
838	>	return r;
839	>	else if ((pl = p.left) != null && h <= pl.hash)
840	>	dir = -1;
841	>	else // nothing there
842	>	return null;
843	>	}
844	>	}
845	>	}
846	>	else
847	>	dir = (h < ph) ? -1 : 1;
848	>	p = (dir > 0) ? p.right : p.left;
849	>	}
850	>	return null;
851	>	}
852
853		/**
854	<	* The total number of mutative operations in this segment.
855	<	* Even though this may overflows 32 bits, it provides
856	<	* sufficient accuracy for stability checks in CHM isEmpty()
310	<	* and size() methods.  Accessed only either within locks or
311	<	* among other volatile reads that maintain visibility.
854	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
855	>	* read-lock to call getTreeNode, but during failure to get
856	>	* lock, searches along next links.
857		*/
858	<	transient int modCount;
858	>	final V getValue(int h, Object k) {
859	>	Node<V> r = null;
860	>	int c = getState(); // Must read lock state first
861	>	for (Node<V> e = first; e != null; e = e.next) {
862	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
863	>	try {
864	>	r = getTreeNode(h, k, root);
865	>	} finally {
866	>	releaseShared(0);
867	>	}
868	>	break;
869	>	}
870	>	else if (e.hash == h && k.equals(e.key)) {
871	>	r = e;
872	>	break;
873	>	}
874	>	else
875	>	c = getState();
876	>	}
877	>	return r == null ? null : r.val;
878	>	}
879
880		/**
881	<	* The table is rehashed when its size exceeds this threshold.
882	<	* (The value of this field is always <tt>(int)(capacity *
318	<	* loadFactor)</tt>.)
881	>	* Finds or adds a node.
882	>	* @return null if added
883		*/
884	<	transient int threshold;
884	>	@SuppressWarnings("unchecked") final TreeNode<V> putTreeNode
885	>	(int h, Object k, V v) {
886	>	Class<?> c = k.getClass();
887	>	TreeNode<V> pp = root, p = null;
888	>	int dir = 0;
889	>	while (pp != null) { // find existing node or leaf to insert at
890	>	int ph;  Object pk; Class<?> pc;
891	>	p = pp;
892	>	if ((ph = p.hash) == h) {
893	>	if ((pk = p.key) == k || k.equals(pk))
894	>	return p;
895	>	if (c != (pc = pk.getClass()) ||
896	>	!(k instanceof Comparable) ||
897	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
898	>	TreeNode<V> s = null, r = null, pr;
899	>	if ((dir = (c == pc) ? 0 :
900	>	c.getName().compareTo(pc.getName())) == 0) {
901	>	if ((pr = p.right) != null && h >= pr.hash &&
902	>	(r = getTreeNode(h, k, pr)) != null)
903	>	return r;
904	>	else // continue left
905	>	dir = -1;
906	>	}
907	>	else if ((pr = p.right) != null && h >= pr.hash)
908	>	s = pr;
909	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
910	>	return r;
911	>	}
912	>	}
913	>	else
914	>	dir = (h < ph) ? -1 : 1;
915	>	pp = (dir > 0) ? p.right : p.left;
916	>	}
917	>
918	>	TreeNode<V> f = first;
919	>	TreeNode<V> x = first = new TreeNode<V>(h, k, v, f, p);
920	>	if (p == null)
921	>	root = x;
922	>	else { // attach and rebalance; adapted from CLR
923	>	TreeNode<V> xp, xpp;
924	>	if (f != null)
925	>	f.prev = x;
926	>	if (dir <= 0)
927	>	p.left = x;
928	>	else
929	>	p.right = x;
930	>	x.red = true;
931	>	while (x != null && (xp = x.parent) != null && xp.red &&
932	>	(xpp = xp.parent) != null) {
933	>	TreeNode<V> xppl = xpp.left;
934	>	if (xp == xppl) {
935	>	TreeNode<V> y = xpp.right;
936	>	if (y != null && y.red) {
937	>	y.red = false;
938	>	xp.red = false;
939	>	xpp.red = true;
940	>	x = xpp;
941	>	}
942	>	else {
943	>	if (x == xp.right) {
944	>	rotateLeft(x = xp);
945	>	xpp = (xp = x.parent) == null ? null : xp.parent;
946	>	}
947	>	if (xp != null) {
948	>	xp.red = false;
949	>	if (xpp != null) {
950	>	xpp.red = true;
951	>	rotateRight(xpp);
952	>	}
953	>	}
954	>	}
955	>	}
956	>	else {
957	>	TreeNode<V> y = xppl;
958	>	if (y != null && y.red) {
959	>	y.red = false;
960	>	xp.red = false;
961	>	xpp.red = true;
962	>	x = xpp;
963	>	}
964	>	else {
965	>	if (x == xp.left) {
966	>	rotateRight(x = xp);
967	>	xpp = (xp = x.parent) == null ? null : xp.parent;
968	>	}
969	>	if (xp != null) {
970	>	xp.red = false;
971	>	if (xpp != null) {
972	>	xpp.red = true;
973	>	rotateLeft(xpp);
974	>	}
975	>	}
976	>	}
977	>	}
978	>	}
979	>	TreeNode<V> r = root;
980	>	if (r != null && r.red)
981	>	r.red = false;
982	>	}
983	>	return null;
984	>	}
985
986		/**
987	<	* The load factor for the hash table.  Even though this value
988	<	* is same for all segments, it is replicated to avoid needing
989	<	* links to outer object.
990	<	* @serial
987	>	* Removes the given node, that must be present before this
988	>	* call.  This is messier than typical red-black deletion code
989	>	* because we cannot swap the contents of an interior node
990	>	* with a leaf successor that is pinned by "next" pointers
991	>	* that are accessible independently of lock. So instead we
992	>	* swap the tree linkages.
993		*/
994	<	final float loadFactor;
994	>	final void deleteTreeNode(TreeNode<V> p) {
995	>	TreeNode<V> next = (TreeNode<V>)p.next; // unlink traversal pointers
996	>	TreeNode<V> pred = p.prev;
997	>	if (pred == null)
998	>	first = next;
999	>	else
1000	>	pred.next = next;
1001	>	if (next != null)
1002	>	next.prev = pred;
1003	>	TreeNode<V> replacement;
1004	>	TreeNode<V> pl = p.left;
1005	>	TreeNode<V> pr = p.right;
1006	>	if (pl != null && pr != null) {
1007	>	TreeNode<V> s = pr, sl;
1008	>	while ((sl = s.left) != null) // find successor
1009	>	s = sl;
1010	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
1011	>	TreeNode<V> sr = s.right;
1012	>	TreeNode<V> pp = p.parent;
1013	>	if (s == pr) { // p was s's direct parent
1014	>	p.parent = s;
1015	>	s.right = p;
1016	>	}
1017	>	else {
1018	>	TreeNode<V> sp = s.parent;
1019	>	if ((p.parent = sp) != null) {
1020	>	if (s == sp.left)
1021	>	sp.left = p;
1022	>	else
1023	>	sp.right = p;
1024	>	}
1025	>	if ((s.right = pr) != null)
1026	>	pr.parent = s;
1027	>	}
1028	>	p.left = null;
1029	>	if ((p.right = sr) != null)
1030	>	sr.parent = p;
1031	>	if ((s.left = pl) != null)
1032	>	pl.parent = s;
1033	>	if ((s.parent = pp) == null)
1034	>	root = s;
1035	>	else if (p == pp.left)
1036	>	pp.left = s;
1037	>	else
1038	>	pp.right = s;
1039	>	replacement = sr;
1040	>	}
1041	>	else
1042	>	replacement = (pl != null) ? pl : pr;
1043	>	TreeNode<V> pp = p.parent;
1044	>	if (replacement == null) {
1045	>	if (pp == null) {
1046	>	root = null;
1047	>	return;
1048	>	}
1049	>	replacement = p;
1050	>	}
1051	>	else {
1052	>	replacement.parent = pp;
1053	>	if (pp == null)
1054	>	root = replacement;
1055	>	else if (p == pp.left)
1056	>	pp.left = replacement;
1057	>	else
1058	>	pp.right = replacement;
1059	>	p.left = p.right = p.parent = null;
1060	>	}
1061	>	if (!p.red) { // rebalance, from CLR
1062	>	TreeNode<V> x = replacement;
1063	>	while (x != null) {
1064	>	TreeNode<V> xp, xpl;
1065	>	if (x.red || (xp = x.parent) == null) {
1066	>	x.red = false;
1067	>	break;
1068	>	}
1069	>	if (x == (xpl = xp.left)) {
1070	>	TreeNode<V> sib = xp.right;
1071	>	if (sib != null && sib.red) {
1072	>	sib.red = false;
1073	>	xp.red = true;
1074	>	rotateLeft(xp);
1075	>	sib = (xp = x.parent) == null ? null : xp.right;
1076	>	}
1077	>	if (sib == null)
1078	>	x = xp;
1079	>	else {
1080	>	TreeNode<V> sl = sib.left, sr = sib.right;
1081	>	if ((sr == null || !sr.red) &&
1082	>	(sl == null || !sl.red)) {
1083	>	sib.red = true;
1084	>	x = xp;
1085	>	}
1086	>	else {
1087	>	if (sr == null || !sr.red) {
1088	>	if (sl != null)
1089	>	sl.red = false;
1090	>	sib.red = true;
1091	>	rotateRight(sib);
1092	>	sib = (xp = x.parent) == null ?
1093	>	null : xp.right;
1094	>	}
1095	>	if (sib != null) {
1096	>	sib.red = (xp == null) ? false : xp.red;
1097	>	if ((sr = sib.right) != null)
1098	>	sr.red = false;
1099	>	}
1100	>	if (xp != null) {
1101	>	xp.red = false;
1102	>	rotateLeft(xp);
1103	>	}
1104	>	x = root;
1105	>	}
1106	>	}
1107	>	}
1108	>	else { // symmetric
1109	>	TreeNode<V> sib = xpl;
1110	>	if (sib != null && sib.red) {
1111	>	sib.red = false;
1112	>	xp.red = true;
1113	>	rotateRight(xp);
1114	>	sib = (xp = x.parent) == null ? null : xp.left;
1115	>	}
1116	>	if (sib == null)
1117	>	x = xp;
1118	>	else {
1119	>	TreeNode<V> sl = sib.left, sr = sib.right;
1120	>	if ((sl == null || !sl.red) &&
1121	>	(sr == null || !sr.red)) {
1122	>	sib.red = true;
1123	>	x = xp;
1124	>	}
1125	>	else {
1126	>	if (sl == null || !sl.red) {
1127	>	if (sr != null)
1128	>	sr.red = false;
1129	>	sib.red = true;
1130	>	rotateLeft(sib);
1131	>	sib = (xp = x.parent) == null ?
1132	>	null : xp.left;
1133	>	}
1134	>	if (sib != null) {
1135	>	sib.red = (xp == null) ? false : xp.red;
1136	>	if ((sl = sib.left) != null)
1137	>	sl.red = false;
1138	>	}
1139	>	if (xp != null) {
1140	>	xp.red = false;
1141	>	rotateRight(xp);
1142	>	}
1143	>	x = root;
1144	>	}
1145	>	}
1146	>	}
1147	>	}
1148	>	}
1149	>	if (p == replacement && (pp = p.parent) != null) {
1150	>	if (p == pp.left) // detach pointers
1151	>	pp.left = null;
1152	>	else if (p == pp.right)
1153	>	pp.right = null;
1154	>	p.parent = null;
1155	>	}
1156	>	}
1157	>	}
1158
1159	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
1160	<	this.loadFactor = lf;
1161	<	this.threshold = threshold;
1162	<	this.table = tab;
1159	>	/* ---------------- Collision reduction methods -------------- */
1160	>
1161	>	/**
1162	>	* Spreads higher bits to lower, and also forces top bit to 0.
1163	>	* Because the table uses power-of-two masking, sets of hashes
1164	>	* that vary only in bits above the current mask will always
1165	>	* collide. (Among known examples are sets of Float keys holding
1166	>	* consecutive whole numbers in small tables.)  To counter this,
1167	>	* we apply a transform that spreads the impact of higher bits
1168	>	* downward. There is a tradeoff between speed, utility, and
1169	>	* quality of bit-spreading. Because many common sets of hashes
1170	>	* are already reasonably distributed across bits (so don't benefit
1171	>	* from spreading), and because we use trees to handle large sets
1172	>	* of collisions in bins, we don't need excessively high quality.
1173	>	*/
1174	>	private static final int spread(int h) {
1175	>	h ^= (h >>> 18) ^ (h >>> 12);
1176	>	return (h ^ (h >>> 10)) & HASH_BITS;
1177	>	}
1178	>
1179	>	/**
1180	>	* Replaces a list bin with a tree bin if key is comparable.  Call
1181	>	* only when locked.
1182	>	*/
1183	>	private final void replaceWithTreeBin(Node<V>[] tab, int index, Object key) {
1184	>	if (key instanceof Comparable) {
1185	>	TreeBin<V> t = new TreeBin<V>();
1186	>	for (Node<V> e = tabAt(tab, index); e != null; e = e.next)
1187	>	t.putTreeNode(e.hash, e.key, e.val);
1188	>	setTabAt(tab, index, new Node<V>(MOVED, t, null, null));
1189		}
1190	+	}
1191
1192	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
1193	<	HashEntry<K,V> node = tryLock() ? null :
1194	<	scanAndLockForPut(key, hash, value);
1195	<	V oldValue;
1196	<	try {
1197	<	HashEntry<K,V>[] tab = table;
1198	<	int index = (tab.length - 1) & hash;
1199	<	HashEntry<K,V> first = entryAt(tab, index);
1200	<	for (HashEntry<K,V> e = first;;) {
1201	<	if (e != null) {
1202	<	K k;
1203	<	if ((k = e.key) == key ||
1204	<	(e.hash == hash && key.equals(k))) {
1205	<	oldValue = e.value;
1206	<	if (!onlyIfAbsent) {
1207	<	e.value = value;
1208	<	++modCount;
1192	>	/* ---------------- Internal access and update methods -------------- */
1193	>
1194	>	/** Implementation for get and containsKey */
1195	>	@SuppressWarnings("unchecked") private final V internalGet(Object k) {
1196	>	int h = spread(k.hashCode());
1197	>	retry: for (Node<V>[] tab = table; tab != null;) {
1198	>	Node<V> e; Object ek; V ev; int eh; // locals to read fields once
1199	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1200	>	if ((eh = e.hash) < 0) {
1201	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1202	>	return ((TreeBin<V>)ek).getValue(h, k);
1203	>	else {                      // restart with new table
1204	>	tab = (Node<V>[])ek;
1205	>	continue retry;
1206	>	}
1207	>	}
1208	>	else if (eh == h && (ev = e.val) != null &&
1209	>	((ek = e.key) == k || k.equals(ek)))
1210	>	return ev;
1211	>	}
1212	>	break;
1213	>	}
1214	>	return null;
1215	>	}
1216	>
1217	>	/**
1218	>	* Implementation for the four public remove/replace methods:
1219	>	* Replaces node value with v, conditional upon match of cv if
1220	>	* non-null.  If resulting value is null, delete.
1221	>	*/
1222	>	@SuppressWarnings("unchecked") private final V internalReplace
1223	>	(Object k, V v, Object cv) {
1224	>	int h = spread(k.hashCode());
1225	>	V oldVal = null;
1226	>	for (Node<V>[] tab = table;;) {
1227	>	Node<V> f; int i, fh; Object fk;
1228	>	if (tab == null ||
1229	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1230	>	break;
1231	>	else if ((fh = f.hash) < 0) {
1232	>	if ((fk = f.key) instanceof TreeBin) {
1233	>	TreeBin<V> t = (TreeBin<V>)fk;
1234	>	boolean validated = false;
1235	>	boolean deleted = false;
1236	>	t.acquire(0);
1237	>	try {
1238	>	if (tabAt(tab, i) == f) {
1239	>	validated = true;
1240	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1241	>	if (p != null) {
1242	>	V pv = p.val;
1243	>	if (cv == null || cv == pv || cv.equals(pv)) {
1244	>	oldVal = pv;
1245	>	if ((p.val = v) == null) {
1246	>	deleted = true;
1247	>	t.deleteTreeNode(p);
1248	>	}
1249	>	}
1250		}
354	–	break;
1251		}
1252	<	e = e.next;
1252	>	} finally {
1253	>	t.release(0);
1254		}
1255	<	else {
1256	<	if (node != null)
1257	<	node.setNext(first);
361	<	else
362	<	node = new HashEntry<K,V>(hash, key, value, first);
363	<	int c = count + 1;
364	<	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
365	<	rehash(node);
366	<	else
367	<	setEntryAt(tab, index, node);
368	<	++modCount;
369	<	count = c;
370	<	oldValue = null;
1255	>	if (validated) {
1256	>	if (deleted)
1257	>	addCount(-1L, -1);
1258		break;
1259		}
1260		}
1261	<	} finally {
1262	<	unlock();
1261	>	else
1262	>	tab = (Node<V>[])fk;
1263	>	}
1264	>	else if (fh != h && f.next == null) // precheck
1265	>	break;                          // rules out possible existence
1266	>	else {
1267	>	boolean validated = false;
1268	>	boolean deleted = false;
1269	>	synchronized (f) {
1270	>	if (tabAt(tab, i) == f) {
1271	>	validated = true;
1272	>	for (Node<V> e = f, pred = null;;) {
1273	>	Object ek; V ev;
1274	>	if (e.hash == h &&
1275	>	((ev = e.val) != null) &&
1276	>	((ek = e.key) == k || k.equals(ek))) {
1277	>	if (cv == null || cv == ev || cv.equals(ev)) {
1278	>	oldVal = ev;
1279	>	if ((e.val = v) == null) {
1280	>	deleted = true;
1281	>	Node<V> en = e.next;
1282	>	if (pred != null)
1283	>	pred.next = en;
1284	>	else
1285	>	setTabAt(tab, i, en);
1286	>	}
1287	>	}
1288	>	break;
1289	>	}
1290	>	pred = e;
1291	>	if ((e = e.next) == null)
1292	>	break;
1293	>	}
1294	>	}
1295	>	}
1296	>	if (validated) {
1297	>	if (deleted)
1298	>	addCount(-1L, -1);
1299	>	break;
1300	>	}
1301		}
377	–	return oldValue;
1302		}
1303	+	return oldVal;
1304	+	}
1305
1306	<	/**
1307	<	* Doubles size of table and repacks entries, also adding the
1308	<	* given node to new table
1309	<	*/
1310	<	@SuppressWarnings("unchecked")
1311	<	private void rehash(HashEntry<K,V> node) {
1312	<	/*
1313	<	* Reclassify nodes in each list to new table.  Because we
1314	<	* are using power-of-two expansion, the elements from
1315	<	* each bin must either stay at same index, or move with a
1316	<	* power of two offset. We eliminate unnecessary node
1317	<	* creation by catching cases where old nodes can be
1318	<	* reused because their next fields won't change.
1319	<	* Statistically, at the default threshold, only about
1320	<	* one-sixth of them need cloning when a table
1321	<	* doubles. The nodes they replace will be garbage
1322	<	* collectable as soon as they are no longer referenced by
1323	<	* any reader thread that may be in the midst of
1324	<	* concurrently traversing table. Entry accesses use plain
1325	<	* array indexing because they are followed by volatile
1326	<	* table write.
1327	<	*/
1328	<	HashEntry<K,V>[] oldTable = table;
1329	<	int oldCapacity = oldTable.length;
1330	<	int newCapacity = oldCapacity << 1;
1331	<	threshold = (int)(newCapacity * loadFactor);
1332	<	HashEntry<K,V>[] newTable =
1333	<	(HashEntry<K,V>[]) new HashEntry[newCapacity];
1334	<	int sizeMask = newCapacity - 1;
1335	<	for (int i = 0; i < oldCapacity ; i++) {
1336	<	HashEntry<K,V> e = oldTable[i];
1337	<	if (e != null) {
1338	<	HashEntry<K,V> next = e.next;
1339	<	int idx = e.hash & sizeMask;
1340	<	if (next == null)   //  Single node on list
1341	<	newTable[idx] = e;
1342	<	else { // Reuse consecutive sequence at same slot
1343	<	HashEntry<K,V> lastRun = e;
1344	<	int lastIdx = idx;
1345	<	for (HashEntry<K,V> last = next;
1346	<	last != null;
1347	<	last = last.next) {
1348	<	int k = last.hash & sizeMask;
1349	<	if (k != lastIdx) {
1350	<	lastIdx = k;
1351	<	lastRun = last;
1352	<	}
1353	<	}
1354	<	newTable[lastIdx] = lastRun;
1355	<	// Clone remaining nodes
1356	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1357	<	V v = p.value;
1358	<	int h = p.hash;
1359	<	int k = h & sizeMask;
434	<	HashEntry<K,V> n = newTable[k];
435	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
436	<	}
437	<	}
438	<	}
439	<	}
440	<	int nodeIndex = node.hash & sizeMask; // add the new node
441	<	node.setNext(newTable[nodeIndex]);
442	<	newTable[nodeIndex] = node;
443	<	table = newTable;
444	<	}
445	<
446	<	/**
447	<	* Scans for a node containing given key while trying to
448	<	* acquire lock, creating and returning one if not found. Upon
449	<	* return, guarantees that lock is held. Unlike in most
450	<	* methods, calls to method equals are not screened: Since
451	<	* traversal speed doesn't matter, we might as well help warm
452	<	* up the associated code and accesses as well.
453	<	*
454	<	* @return a new node if key not found, else null
455	<	*/
456	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
457	<	HashEntry<K,V> first = entryForHash(this, hash);
458	<	HashEntry<K,V> e = first;
459	<	HashEntry<K,V> node = null;
460	<	int retries = -1; // negative while locating node
461	<	while (!tryLock()) {
462	<	HashEntry<K,V> f; // to recheck first below
463	<	if (retries < 0) {
464	<	if (e == null) {
465	<	if (node == null) // speculatively create node
466	<	node = new HashEntry<K,V>(hash, key, value, null);
467	<	retries = 0;
1306	>	/*
1307	>	* Internal versions of insertion methods
1308	>	* All have the same basic structure as the first (internalPut):
1309	>	*  1. If table uninitialized, create
1310	>	*  2. If bin empty, try to CAS new node
1311	>	*  3. If bin stale, use new table
1312	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1313	>	*  5. Lock and validate; if valid, scan and add or update
1314	>	*
1315	>	* The putAll method differs mainly in attempting to pre-allocate
1316	>	* enough table space, and also more lazily performs count updates
1317	>	* and checks.
1318	>	*
1319	>	* Most of the function-accepting methods can't be factored nicely
1320	>	* because they require different functional forms, so instead
1321	>	* sprawl out similar mechanics.
1322	>	*/
1323	>
1324	>	/** Implementation for put and putIfAbsent */
1325	>	@SuppressWarnings("unchecked") private final V internalPut
1326	>	(K k, V v, boolean onlyIfAbsent) {
1327	>	if (k == null || v == null) throw new NullPointerException();
1328	>	int h = spread(k.hashCode());
1329	>	int len = 0;
1330	>	for (Node<V>[] tab = table;;) {
1331	>	int i, fh; Node<V> f; Object fk; V fv;
1332	>	if (tab == null)
1333	>	tab = initTable();
1334	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1335	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null)))
1336	>	break;                   // no lock when adding to empty bin
1337	>	}
1338	>	else if ((fh = f.hash) < 0) {
1339	>	if ((fk = f.key) instanceof TreeBin) {
1340	>	TreeBin<V> t = (TreeBin<V>)fk;
1341	>	V oldVal = null;
1342	>	t.acquire(0);
1343	>	try {
1344	>	if (tabAt(tab, i) == f) {
1345	>	len = 2;
1346	>	TreeNode<V> p = t.putTreeNode(h, k, v);
1347	>	if (p != null) {
1348	>	oldVal = p.val;
1349	>	if (!onlyIfAbsent)
1350	>	p.val = v;
1351	>	}
1352	>	}
1353	>	} finally {
1354	>	t.release(0);
1355	>	}
1356	>	if (len != 0) {
1357	>	if (oldVal != null)
1358	>	return oldVal;
1359	>	break;
1360		}
469	–	else if (key.equals(e.key))
470	–	retries = 0;
471	–	else
472	–	e = e.next;
1361		}
1362	<	else if (++retries > MAX_SCAN_RETRIES) {
1363	<	lock();
1362	>	else
1363	>	tab = (Node<V>[])fk;
1364	>	}
1365	>	else if (onlyIfAbsent && fh == h && (fv = f.val) != null &&
1366	>	((fk = f.key) == k || k.equals(fk))) // peek while nearby
1367	>	return fv;
1368	>	else {
1369	>	V oldVal = null;
1370	>	synchronized (f) {
1371	>	if (tabAt(tab, i) == f) {
1372	>	len = 1;
1373	>	for (Node<V> e = f;; ++len) {
1374	>	Object ek; V ev;
1375	>	if (e.hash == h &&
1376	>	(ev = e.val) != null &&
1377	>	((ek = e.key) == k || k.equals(ek))) {
1378	>	oldVal = ev;
1379	>	if (!onlyIfAbsent)
1380	>	e.val = v;
1381	>	break;
1382	>	}
1383	>	Node<V> last = e;
1384	>	if ((e = e.next) == null) {
1385	>	last.next = new Node<V>(h, k, v, null);
1386	>	if (len >= TREE_THRESHOLD)
1387	>	replaceWithTreeBin(tab, i, k);
1388	>	break;
1389	>	}
1390	>	}
1391	>	}
1392	>	}
1393	>	if (len != 0) {
1394	>	if (oldVal != null)
1395	>	return oldVal;
1396		break;
1397		}
1398	<	else if ((retries & 1) == 0 &&
479	<	(f = entryForHash(this, hash)) != first) {
480	<	e = first = f; // re-traverse if entry changed
481	<	retries = -1;
482	<	}
483	<	}
484	<	return node;
1398	>	}
1399		}
1400	+	addCount(1L, len);
1401	+	return null;
1402	+	}
1403
1404	<	/**
1405	<	* Scans for a node containing the given key while trying to
1406	<	* acquire lock for a remove or replace operation. Upon
1407	<	* return, guarantees that lock is held.  Note that we must
1408	<	* lock even if the key is not found, to ensure sequential
1409	<	* consistency of updates.
1410	<	*/
1411	<	private void scanAndLock(Object key, int hash) {
1412	<	// similar to but simpler than scanAndLockForPut
1413	<	HashEntry<K,V> first = entryForHash(this, hash);
1414	<	HashEntry<K,V> e = first;
1415	<	int retries = -1;
1416	<	while (!tryLock()) {
1417	<	HashEntry<K,V> f;
1418	<	if (retries < 0) {
1419	<	if (e == null || key.equals(e.key))
1420	<	retries = 0;
1421	<	else
1422	<	e = e.next;
1404	>	/** Implementation for computeIfAbsent */
1405	>	@SuppressWarnings("unchecked") private final V internalComputeIfAbsent
1406	>	(K k, Fun<? super K, ? extends V> mf) {
1407	>	if (k == null || mf == null)
1408	>	throw new NullPointerException();
1409	>	int h = spread(k.hashCode());
1410	>	V val = null;
1411	>	int len = 0;
1412	>	for (Node<V>[] tab = table;;) {
1413	>	Node<V> f; int i; Object fk;
1414	>	if (tab == null)
1415	>	tab = initTable();
1416	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1417	>	Node<V> node = new Node<V>(h, k, null, null);
1418	>	synchronized (node) {
1419	>	if (casTabAt(tab, i, null, node)) {
1420	>	len = 1;
1421	>	try {
1422	>	if ((val = mf.apply(k)) != null)
1423	>	node.val = val;
1424	>	} finally {
1425	>	if (val == null)
1426	>	setTabAt(tab, i, null);
1427	>	}
1428	>	}
1429		}
1430	<	else if (++retries > MAX_SCAN_RETRIES) {
508	<	lock();
1430	>	if (len != 0)
1431		break;
1432	+	}
1433	+	else if (f.hash < 0) {
1434	+	if ((fk = f.key) instanceof TreeBin) {
1435	+	TreeBin<V> t = (TreeBin<V>)fk;
1436	+	boolean added = false;
1437	+	t.acquire(0);
1438	+	try {
1439	+	if (tabAt(tab, i) == f) {
1440	+	len = 1;
1441	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1442	+	if (p != null)
1443	+	val = p.val;
1444	+	else if ((val = mf.apply(k)) != null) {
1445	+	added = true;
1446	+	len = 2;
1447	+	t.putTreeNode(h, k, val);
1448	+	}
1449	+	}
1450	+	} finally {
1451	+	t.release(0);
1452	+	}
1453	+	if (len != 0) {
1454	+	if (!added)
1455	+	return val;
1456	+	break;
1457	+	}
1458	+	}
1459	+	else
1460	+	tab = (Node<V>[])fk;
1461	+	}
1462	+	else {
1463	+	for (Node<V> e = f; e != null; e = e.next) { // prescan
1464	+	Object ek; V ev;
1465	+	if (e.hash == h && (ev = e.val) != null &&
1466	+	((ek = e.key) == k || k.equals(ek)))
1467	+	return ev;
1468	+	}
1469	+	boolean added = false;
1470	+	synchronized (f) {
1471	+	if (tabAt(tab, i) == f) {
1472	+	len = 1;
1473	+	for (Node<V> e = f;; ++len) {
1474	+	Object ek; V ev;
1475	+	if (e.hash == h &&
1476	+	(ev = e.val) != null &&
1477	+	((ek = e.key) == k || k.equals(ek))) {
1478	+	val = ev;
1479	+	break;
1480	+	}
1481	+	Node<V> last = e;
1482	+	if ((e = e.next) == null) {
1483	+	if ((val = mf.apply(k)) != null) {
1484	+	added = true;
1485	+	last.next = new Node<V>(h, k, val, null);
1486	+	if (len >= TREE_THRESHOLD)
1487	+	replaceWithTreeBin(tab, i, k);
1488	+	}
1489	+	break;
1490	+	}
1491	+	}
1492	+	}
1493		}
1494	<	else if ((retries & 1) == 0 &&
1495	<	(f = entryForHash(this, hash)) != first) {
1496	<	e = first = f;
1497	<	retries = -1;
1494	>	if (len != 0) {
1495	>	if (!added)
1496	>	return val;
1497	>	break;
1498		}
1499		}
1500		}
1501	+	if (val != null)
1502	+	addCount(1L, len);
1503	+	return val;
1504	+	}
1505
1506	<	/**
1507	<	* Remove; match on key only if value null, else match both.
1508	<	*/
1509	<	final V remove(Object key, int hash, Object value) {
1510	<	if (!tryLock())
1511	<	scanAndLock(key, hash);
1512	<	V oldValue = null;
1513	<	try {
1514	<	HashEntry<K,V>[] tab = table;
1515	<	int index = (tab.length - 1) & hash;
1516	<	HashEntry<K,V> e = entryAt(tab, index);
1517	<	HashEntry<K,V> pred = null;
1518	<	while (e != null) {
1519	<	K k;
1520	<	HashEntry<K,V> next = e.next;
1521	<	if ((k = e.key) == key ||
1522	<	(e.hash == hash && key.equals(k))) {
1523	<	V v = e.value;
1524	<	if (value == null || value == v || value.equals(v)) {
1525	<	if (pred == null)
1526	<	setEntryAt(tab, index, next);
1527	<	else
1528	<	pred.setNext(next);
1529	<	++modCount;
1530	<	--count;
1531	<	oldValue = v;
1506	>	/** Implementation for compute */
1507	>	@SuppressWarnings("unchecked") private final V internalCompute
1508	>	(K k, boolean onlyIfPresent,
1509	>	BiFun<? super K, ? super V, ? extends V> mf) {
1510	>	if (k == null || mf == null)
1511	>	throw new NullPointerException();
1512	>	int h = spread(k.hashCode());
1513	>	V val = null;
1514	>	int delta = 0;
1515	>	int len = 0;
1516	>	for (Node<V>[] tab = table;;) {
1517	>	Node<V> f; int i, fh; Object fk;
1518	>	if (tab == null)
1519	>	tab = initTable();
1520	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1521	>	if (onlyIfPresent)
1522	>	break;
1523	>	Node<V> node = new Node<V>(h, k, null, null);
1524	>	synchronized (node) {
1525	>	if (casTabAt(tab, i, null, node)) {
1526	>	try {
1527	>	len = 1;
1528	>	if ((val = mf.apply(k, null)) != null) {
1529	>	node.val = val;
1530	>	delta = 1;
1531	>	}
1532	>	} finally {
1533	>	if (delta == 0)
1534	>	setTabAt(tab, i, null);
1535	>	}
1536	>	}
1537	>	}
1538	>	if (len != 0)
1539	>	break;
1540	>	}
1541	>	else if ((fh = f.hash) < 0) {
1542	>	if ((fk = f.key) instanceof TreeBin) {
1543	>	TreeBin<V> t = (TreeBin<V>)fk;
1544	>	t.acquire(0);
1545	>	try {
1546	>	if (tabAt(tab, i) == f) {
1547	>	len = 1;
1548	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1549	>	if (p == null && onlyIfPresent)
1550	>	break;
1551	>	V pv = (p == null) ? null : p.val;
1552	>	if ((val = mf.apply(k, pv)) != null) {
1553	>	if (p != null)
1554	>	p.val = val;
1555	>	else {
1556	>	len = 2;
1557	>	delta = 1;
1558	>	t.putTreeNode(h, k, val);
1559	>	}
1560	>	}
1561	>	else if (p != null) {
1562	>	delta = -1;
1563	>	t.deleteTreeNode(p);
1564	>	}
1565		}
1566	+	} finally {
1567	+	t.release(0);
1568	+	}
1569	+	if (len != 0)
1570		break;
1571	+	}
1572	+	else
1573	+	tab = (Node<V>[])fk;
1574	+	}
1575	+	else {
1576	+	synchronized (f) {
1577	+	if (tabAt(tab, i) == f) {
1578	+	len = 1;
1579	+	for (Node<V> e = f, pred = null;; ++len) {
1580	+	Object ek; V ev;
1581	+	if (e.hash == h &&
1582	+	(ev = e.val) != null &&
1583	+	((ek = e.key) == k || k.equals(ek))) {
1584	+	val = mf.apply(k, ev);
1585	+	if (val != null)
1586	+	e.val = val;
1587	+	else {
1588	+	delta = -1;
1589	+	Node<V> en = e.next;
1590	+	if (pred != null)
1591	+	pred.next = en;
1592	+	else
1593	+	setTabAt(tab, i, en);
1594	+	}
1595	+	break;
1596	+	}
1597	+	pred = e;
1598	+	if ((e = e.next) == null) {
1599	+	if (!onlyIfPresent &&
1600	+	(val = mf.apply(k, null)) != null) {
1601	+	pred.next = new Node<V>(h, k, val, null);
1602	+	delta = 1;
1603	+	if (len >= TREE_THRESHOLD)
1604	+	replaceWithTreeBin(tab, i, k);
1605	+	}
1606	+	break;
1607	+	}
1608	+	}
1609		}
548	–	pred = e;
549	–	e = next;
1610		}
1611	<	} finally {
1612	<	unlock();
1611	>	if (len != 0)
1612	>	break;
1613		}
554	–	return oldValue;
1614		}
1615	+	if (delta != 0)
1616	+	addCount((long)delta, len);
1617	+	return val;
1618	+	}
1619
1620	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
1621	<	if (!tryLock())
1622	<	scanAndLock(key, hash);
1623	<	boolean replaced = false;
1624	<	try {
1625	<	HashEntry<K,V> e;
1626	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1627	<	K k;
1628	<	if ((k = e.key) == key ||
1629	<	(e.hash == hash && key.equals(k))) {
1630	<	if (oldValue.equals(e.value)) {
1631	<	e.value = newValue;
1632	<	++modCount;
1633	<	replaced = true;
1620	>	/** Implementation for merge */
1621	>	@SuppressWarnings("unchecked") private final V internalMerge
1622	>	(K k, V v, BiFun<? super V, ? super V, ? extends V> mf) {
1623	>	if (k == null || v == null || mf == null)
1624	>	throw new NullPointerException();
1625	>	int h = spread(k.hashCode());
1626	>	V val = null;
1627	>	int delta = 0;
1628	>	int len = 0;
1629	>	for (Node<V>[] tab = table;;) {
1630	>	int i; Node<V> f; Object fk; V fv;
1631	>	if (tab == null)
1632	>	tab = initTable();
1633	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1634	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1635	>	delta = 1;
1636	>	val = v;
1637	>	break;
1638	>	}
1639	>	}
1640	>	else if (f.hash < 0) {
1641	>	if ((fk = f.key) instanceof TreeBin) {
1642	>	TreeBin<V> t = (TreeBin<V>)fk;
1643	>	t.acquire(0);
1644	>	try {
1645	>	if (tabAt(tab, i) == f) {
1646	>	len = 1;
1647	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1648	>	val = (p == null) ? v : mf.apply(p.val, v);
1649	>	if (val != null) {
1650	>	if (p != null)
1651	>	p.val = val;
1652	>	else {
1653	>	len = 2;
1654	>	delta = 1;
1655	>	t.putTreeNode(h, k, val);
1656	>	}
1657	>	}
1658	>	else if (p != null) {
1659	>	delta = -1;
1660	>	t.deleteTreeNode(p);
1661	>	}
1662		}
1663	+	} finally {
1664	+	t.release(0);
1665	+	}
1666	+	if (len != 0)
1667		break;
1668	+	}
1669	+	else
1670	+	tab = (Node<V>[])fk;
1671	+	}
1672	+	else {
1673	+	synchronized (f) {
1674	+	if (tabAt(tab, i) == f) {
1675	+	len = 1;
1676	+	for (Node<V> e = f, pred = null;; ++len) {
1677	+	Object ek; V ev;
1678	+	if (e.hash == h &&
1679	+	(ev = e.val) != null &&
1680	+	((ek = e.key) == k || k.equals(ek))) {
1681	+	val = mf.apply(ev, v);
1682	+	if (val != null)
1683	+	e.val = val;
1684	+	else {
1685	+	delta = -1;
1686	+	Node<V> en = e.next;
1687	+	if (pred != null)
1688	+	pred.next = en;
1689	+	else
1690	+	setTabAt(tab, i, en);
1691	+	}
1692	+	break;
1693	+	}
1694	+	pred = e;
1695	+	if ((e = e.next) == null) {
1696	+	val = v;
1697	+	pred.next = new Node<V>(h, k, val, null);
1698	+	delta = 1;
1699	+	if (len >= TREE_THRESHOLD)
1700	+	replaceWithTreeBin(tab, i, k);
1701	+	break;
1702	+	}
1703	+	}
1704	+	}
1705	+	}
1706	+	if (len != 0)
1707	+	break;
1708	+	}
1709	+	}
1710	+	if (delta != 0)
1711	+	addCount((long)delta, len);
1712	+	return val;
1713	+	}
1714	+
1715	+	/** Implementation for putAll */
1716	+	@SuppressWarnings("unchecked") private final void internalPutAll
1717	+	(Map<? extends K, ? extends V> m) {
1718	+	tryPresize(m.size());
1719	+	long delta = 0L;     // number of uncommitted additions
1720	+	boolean npe = false; // to throw exception on exit for nulls
1721	+	try {                // to clean up counts on other exceptions
1722	+	for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
1723	+	Object k; V v;
1724	+	if (entry == null || (k = entry.getKey()) == null ||
1725	+	(v = entry.getValue()) == null) {
1726	+	npe = true;
1727	+	break;
1728	+	}
1729	+	int h = spread(k.hashCode());
1730	+	for (Node<V>[] tab = table;;) {
1731	+	int i; Node<V> f; int fh; Object fk;
1732	+	if (tab == null)
1733	+	tab = initTable();
1734	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1735	+	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1736	+	++delta;
1737	+	break;
1738	+	}
1739	+	}
1740	+	else if ((fh = f.hash) < 0) {
1741	+	if ((fk = f.key) instanceof TreeBin) {
1742	+	TreeBin<V> t = (TreeBin<V>)fk;
1743	+	boolean validated = false;
1744	+	t.acquire(0);
1745	+	try {
1746	+	if (tabAt(tab, i) == f) {
1747	+	validated = true;
1748	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1749	+	if (p != null)
1750	+	p.val = v;
1751	+	else {
1752	+	t.putTreeNode(h, k, v);
1753	+	++delta;
1754	+	}
1755	+	}
1756	+	} finally {
1757	+	t.release(0);
1758	+	}
1759	+	if (validated)
1760	+	break;
1761	+	}
1762	+	else
1763	+	tab = (Node<V>[])fk;
1764	+	}
1765	+	else {
1766	+	int len = 0;
1767	+	synchronized (f) {
1768	+	if (tabAt(tab, i) == f) {
1769	+	len = 1;
1770	+	for (Node<V> e = f;; ++len) {
1771	+	Object ek; V ev;
1772	+	if (e.hash == h &&
1773	+	(ev = e.val) != null &&
1774	+	((ek = e.key) == k || k.equals(ek))) {
1775	+	e.val = v;
1776	+	break;
1777	+	}
1778	+	Node<V> last = e;
1779	+	if ((e = e.next) == null) {
1780	+	++delta;
1781	+	last.next = new Node<V>(h, k, v, null);
1782	+	if (len >= TREE_THRESHOLD)
1783	+	replaceWithTreeBin(tab, i, k);
1784	+	break;
1785	+	}
1786	+	}
1787	+	}
1788	+	}
1789	+	if (len != 0) {
1790	+	if (len > 1)
1791	+	addCount(delta, len);
1792	+	break;
1793	+	}
1794		}
1795		}
575	–	} finally {
576	–	unlock();
1796		}
1797	<	return replaced;
1797	>	} finally {
1798	>	if (delta != 0L)
1799	>	addCount(delta, 2);
1800		}
1801	+	if (npe)
1802	+	throw new NullPointerException();
1803	+	}
1804
1805	<	final V replace(K key, int hash, V value) {
1806	<	if (!tryLock())
1807	<	scanAndLock(key, hash);
1808	<	V oldValue = null;
1809	<	try {
1810	<	HashEntry<K,V> e;
1811	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1812	<	K k;
1813	<	if ((k = e.key) == key ||
1814	<	(e.hash == hash && key.equals(k))) {
1815	<	oldValue = e.value;
1816	<	e.value = value;
1817	<	++modCount;
1805	>	/**
1806	>	* Implementation for clear. Steps through each bin, removing all
1807	>	* nodes.
1808	>	*/
1809	>	@SuppressWarnings("unchecked") private final void internalClear() {
1810	>	long delta = 0L; // negative number of deletions
1811	>	int i = 0;
1812	>	Node<V>[] tab = table;
1813	>	while (tab != null && i < tab.length) {
1814	>	Node<V> f = tabAt(tab, i);
1815	>	if (f == null)
1816	>	++i;
1817	>	else if (f.hash < 0) {
1818	>	Object fk;
1819	>	if ((fk = f.key) instanceof TreeBin) {
1820	>	TreeBin<V> t = (TreeBin<V>)fk;
1821	>	t.acquire(0);
1822	>	try {
1823	>	if (tabAt(tab, i) == f) {
1824	>	for (Node<V> p = t.first; p != null; p = p.next) {
1825	>	if (p.val != null) { // (currently always true)
1826	>	p.val = null;
1827	>	--delta;
1828	>	}
1829	>	}
1830	>	t.first = null;
1831	>	t.root = null;
1832	>	++i;
1833	>	}
1834	>	} finally {
1835	>	t.release(0);
1836	>	}
1837	>	}
1838	>	else
1839	>	tab = (Node<V>[])fk;
1840	>	}
1841	>	else {
1842	>	synchronized (f) {
1843	>	if (tabAt(tab, i) == f) {
1844	>	for (Node<V> e = f; e != null; e = e.next) {
1845	>	if (e.val != null) {  // (currently always true)
1846	>	e.val = null;
1847	>	--delta;
1848	>	}
1849	>	}
1850	>	setTabAt(tab, i, null);
1851	>	++i;
1852	>	}
1853	>	}
1854	>	}
1855	>	}
1856	>	if (delta != 0L)
1857	>	addCount(delta, -1);
1858	>	}
1859	>
1860	>	/* ---------------- Table Initialization and Resizing -------------- */
1861	>
1862	>	/**
1863	>	* Returns a power of two table size for the given desired capacity.
1864	>	* See Hackers Delight, sec 3.2
1865	>	*/
1866	>	private static final int tableSizeFor(int c) {
1867	>	int n = c - 1;
1868	>	n |= n >>> 1;
1869	>	n |= n >>> 2;
1870	>	n |= n >>> 4;
1871	>	n |= n >>> 8;
1872	>	n |= n >>> 16;
1873	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1874	>	}
1875	>
1876	>	/**
1877	>	* Initializes table, using the size recorded in sizeCtl.
1878	>	*/
1879	>	@SuppressWarnings("unchecked") private final Node<V>[] initTable() {
1880	>	Node<V>[] tab; int sc;
1881	>	while ((tab = table) == null) {
1882	>	if ((sc = sizeCtl) < 0)
1883	>	Thread.yield(); // lost initialization race; just spin
1884	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1885	>	try {
1886	>	if ((tab = table) == null) {
1887	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1888	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1889	>	table = tab = (Node<V>[])tb;
1890	>	sc = n - (n >>> 2);
1891	>	}
1892	>	} finally {
1893	>	sizeCtl = sc;
1894	>	}
1895	>	break;
1896	>	}
1897	>	}
1898	>	return tab;
1899	>	}
1900	>
1901	>	/**
1902	>	* Adds to count, and if table is too small and not already
1903	>	* resizing, initiates transfer. If already resizing, helps
1904	>	* perform transfer if work is available.  Rechecks occupancy
1905	>	* after a transfer to see if another resize is already needed
1906	>	* because resizings are lagging additions.
1907	>	*
1908	>	* @param x the count to add
1909	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
1910	>	*/
1911	>	private final void addCount(long x, int check) {
1912	>	CounterCell[] as; long b, s;
1913	>	if ((as = counterCells) != null ||
1914	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
1915	>	CounterHashCode hc; CounterCell a; long v; int m;
1916	>	boolean uncontended = true;
1917	>	if ((hc = threadCounterHashCode.get()) == null ||
1918	>	as == null || (m = as.length - 1) < 0 ||
1919	>	(a = as[m & hc.code]) == null ||
1920	>	!(uncontended =
1921	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
1922	>	fullAddCount(x, hc, uncontended);
1923	>	return;
1924	>	}
1925	>	if (check <= 1)
1926	>	return;
1927	>	s = sumCount();
1928	>	}
1929	>	if (check >= 0) {
1930	>	Node<V>[] tab, nt; int sc;
1931	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
1932	>	tab.length < MAXIMUM_CAPACITY) {
1933	>	if (sc < 0) {
1934	>	if (sc == -1 || transferIndex <= transferOrigin ||
1935	>	(nt = nextTable) == null)
1936		break;
1937	+	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
1938	+	transfer(tab, nt);
1939	+	}
1940	+	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
1941	+	transfer(tab, null);
1942	+	s = sumCount();
1943	+	}
1944	+	}
1945	+	}
1946	+
1947	+	/**
1948	+	* Tries to presize table to accommodate the given number of elements.
1949	+	*
1950	+	* @param size number of elements (doesn't need to be perfectly accurate)
1951	+	*/
1952	+	@SuppressWarnings("unchecked") private final void tryPresize(int size) {
1953	+	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1954	+	tableSizeFor(size + (size >>> 1) + 1);
1955	+	int sc;
1956	+	while ((sc = sizeCtl) >= 0) {
1957	+	Node<V>[] tab = table; int n;
1958	+	if (tab == null || (n = tab.length) == 0) {
1959	+	n = (sc > c) ? sc : c;
1960	+	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1961	+	try {
1962	+	if (table == tab) {
1963	+	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1964	+	table = (Node<V>[])tb;
1965	+	sc = n - (n >>> 2);
1966	+	}
1967	+	} finally {
1968	+	sizeCtl = sc;
1969		}
1970		}
597	–	} finally {
598	–	unlock();
1971		}
1972	<	return oldValue;
1972	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1973	>	break;
1974	>	else if (tab == table &&
1975	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
1976	>	transfer(tab, null);
1977		}
1978	+	}
1979
1980	<	final void clear() {
1981	<	lock();
1980	>	/*
1981	>	* Moves and/or copies the nodes in each bin to new table. See
1982	>	* above for explanation.
1983	>	*/
1984	>	@SuppressWarnings("unchecked") private final void transfer
1985	>	(Node<V>[] tab, Node<V>[] nextTab) {
1986	>	int n = tab.length, stride;
1987	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
1988	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
1989	>	if (nextTab == null) {            // initiating
1990		try {
1991	<	HashEntry<K,V>[] tab = table;
1992	<	for (int i = 0; i < tab.length ; i++)
1993	<	setEntryAt(tab, i, null);
1994	<	++modCount;
1995	<	count = 0;
1996	<	} finally {
1997	<	unlock();
1991	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n << 1];
1992	>	nextTab = (Node<V>[])tb;
1993	>	} catch (Throwable ex) {      // try to cope with OOME
1994	>	sizeCtl = Integer.MAX_VALUE;
1995	>	return;
1996	>	}
1997	>	nextTable = nextTab;
1998	>	transferOrigin = n;
1999	>	transferIndex = n;
2000	>	Node<V> rev = new Node<V>(MOVED, tab, null, null);
2001	>	for (int k = n; k > 0;) {    // progressively reveal ready slots
2002	>	int nextk = (k > stride) ? k - stride : 0;
2003	>	for (int m = nextk; m < k; ++m)
2004	>	nextTab[m] = rev;
2005	>	for (int m = n + nextk; m < n + k; ++m)
2006	>	nextTab[m] = rev;
2007	>	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
2008		}
2009		}
2010	+	int nextn = nextTab.length;
2011	+	Node<V> fwd = new Node<V>(MOVED, nextTab, null, null);
2012	+	boolean advance = true;
2013	+	for (int i = 0, bound = 0;;) {
2014	+	int nextIndex, nextBound; Node<V> f; Object fk;
2015	+	while (advance) {
2016	+	if (--i >= bound)
2017	+	advance = false;
2018	+	else if ((nextIndex = transferIndex) <= transferOrigin) {
2019	+	i = -1;
2020	+	advance = false;
2021	+	}
2022	+	else if (U.compareAndSwapInt
2023	+	(this, TRANSFERINDEX, nextIndex,
2024	+	nextBound = (nextIndex > stride ?
2025	+	nextIndex - stride : 0))) {
2026	+	bound = nextBound;
2027	+	i = nextIndex - 1;
2028	+	advance = false;
2029	+	}
2030	+	}
2031	+	if (i < 0 || i >= n || i + n >= nextn) {
2032	+	for (int sc;;) {
2033	+	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
2034	+	if (sc == -1) {
2035	+	nextTable = null;
2036	+	table = nextTab;
2037	+	sizeCtl = (n << 1) - (n >>> 1);
2038	+	}
2039	+	return;
2040	+	}
2041	+	}
2042	+	}
2043	+	else if ((f = tabAt(tab, i)) == null) {
2044	+	if (casTabAt(tab, i, null, fwd)) {
2045	+	setTabAt(nextTab, i, null);
2046	+	setTabAt(nextTab, i + n, null);
2047	+	advance = true;
2048	+	}
2049	+	}
2050	+	else if (f.hash >= 0) {
2051	+	synchronized (f) {
2052	+	if (tabAt(tab, i) == f) {
2053	+	int runBit = f.hash & n;
2054	+	Node<V> lastRun = f, lo = null, hi = null;
2055	+	for (Node<V> p = f.next; p != null; p = p.next) {
2056	+	int b = p.hash & n;
2057	+	if (b != runBit) {
2058	+	runBit = b;
2059	+	lastRun = p;
2060	+	}
2061	+	}
2062	+	if (runBit == 0)
2063	+	lo = lastRun;
2064	+	else
2065	+	hi = lastRun;
2066	+	for (Node<V> p = f; p != lastRun; p = p.next) {
2067	+	int ph = p.hash;
2068	+	Object pk = p.key; V pv = p.val;
2069	+	if ((ph & n) == 0)
2070	+	lo = new Node<V>(ph, pk, pv, lo);
2071	+	else
2072	+	hi = new Node<V>(ph, pk, pv, hi);
2073	+	}
2074	+	setTabAt(nextTab, i, lo);
2075	+	setTabAt(nextTab, i + n, hi);
2076	+	setTabAt(tab, i, fwd);
2077	+	advance = true;
2078	+	}
2079	+	}
2080	+	}
2081	+	else if ((fk = f.key) instanceof TreeBin) {
2082	+	TreeBin<V> t = (TreeBin<V>)fk;
2083	+	t.acquire(0);
2084	+	try {
2085	+	if (tabAt(tab, i) == f) {
2086	+	TreeBin<V> lt = new TreeBin<V>();
2087	+	TreeBin<V> ht = new TreeBin<V>();
2088	+	int lc = 0, hc = 0;
2089	+	for (Node<V> e = t.first; e != null; e = e.next) {
2090	+	int h = e.hash;
2091	+	Object k = e.key; V v = e.val;
2092	+	if ((h & n) == 0) {
2093	+	++lc;
2094	+	lt.putTreeNode(h, k, v);
2095	+	}
2096	+	else {
2097	+	++hc;
2098	+	ht.putTreeNode(h, k, v);
2099	+	}
2100	+	}
2101	+	Node<V> ln, hn; // throw away trees if too small
2102	+	if (lc < TREE_THRESHOLD) {
2103	+	ln = null;
2104	+	for (Node<V> p = lt.first; p != null; p = p.next)
2105	+	ln = new Node<V>(p.hash, p.key, p.val, ln);
2106	+	}
2107	+	else
2108	+	ln = new Node<V>(MOVED, lt, null, null);
2109	+	setTabAt(nextTab, i, ln);
2110	+	if (hc < TREE_THRESHOLD) {
2111	+	hn = null;
2112	+	for (Node<V> p = ht.first; p != null; p = p.next)
2113	+	hn = new Node<V>(p.hash, p.key, p.val, hn);
2114	+	}
2115	+	else
2116	+	hn = new Node<V>(MOVED, ht, null, null);
2117	+	setTabAt(nextTab, i + n, hn);
2118	+	setTabAt(tab, i, fwd);
2119	+	advance = true;
2120	+	}
2121	+	} finally {
2122	+	t.release(0);
2123	+	}
2124	+	}
2125	+	else
2126	+	advance = true; // already processed
2127	+	}
2128	+	}
2129	+
2130	+	/* ---------------- Counter support -------------- */
2131	+
2132	+	final long sumCount() {
2133	+	CounterCell[] as = counterCells; CounterCell a;
2134	+	long sum = baseCount;
2135	+	if (as != null) {
2136	+	for (int i = 0; i < as.length; ++i) {
2137	+	if ((a = as[i]) != null)
2138	+	sum += a.value;
2139	+	}
2140	+	}
2141	+	return sum;
2142		}
2143
2144	<	// Accessing segments
2145	<
2146	<	/**
2147	<	* Gets the jth element of given segment array (if nonnull) with
2148	<	* volatile element access semantics via Unsafe. (The null check
2149	<	* can trigger harmlessly only during deserialization.) Note:
2150	<	* because each element of segments array is set only once (using
2151	<	* fully ordered writes), some performance-sensitive methods rely
2152	<	* on this method only as a recheck upon null reads.
2153	<	*/
2154	<	@SuppressWarnings("unchecked")
2155	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
2156	<	long u = (j << SSHIFT) + SBASE;
2157	<	return ss == null ? null :
2158	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
2144	>	// See LongAdder version for explanation
2145	>	private final void fullAddCount(long x, CounterHashCode hc,
2146	>	boolean wasUncontended) {
2147	>	int h;
2148	>	if (hc == null) {
2149	>	hc = new CounterHashCode();
2150	>	int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT);
2151	>	h = hc.code = (s == 0) ? 1 : s; // Avoid zero
2152	>	threadCounterHashCode.set(hc);
2153	>	}
2154	>	else
2155	>	h = hc.code;
2156	>	boolean collide = false;                // True if last slot nonempty
2157	>	for (;;) {
2158	>	CounterCell[] as; CounterCell a; int n; long v;
2159	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2160	>	if ((a = as[(n - 1) & h]) == null) {
2161	>	if (counterBusy == 0) {            // Try to attach new Cell
2162	>	CounterCell r = new CounterCell(x); // Optimistic create
2163	>	if (counterBusy == 0 &&
2164	>	U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
2165	>	boolean created = false;
2166	>	try {               // Recheck under lock
2167	>	CounterCell[] rs; int m, j;
2168	>	if ((rs = counterCells) != null &&
2169	>	(m = rs.length) > 0 &&
2170	>	rs[j = (m - 1) & h] == null) {
2171	>	rs[j] = r;
2172	>	created = true;
2173	>	}
2174	>	} finally {
2175	>	counterBusy = 0;
2176	>	}
2177	>	if (created)
2178	>	break;
2179	>	continue;           // Slot is now non-empty
2180	>	}
2181	>	}
2182	>	collide = false;
2183	>	}
2184	>	else if (!wasUncontended)       // CAS already known to fail
2185	>	wasUncontended = true;      // Continue after rehash
2186	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2187	>	break;
2188	>	else if (counterCells != as || n >= NCPU)
2189	>	collide = false;            // At max size or stale
2190	>	else if (!collide)
2191	>	collide = true;
2192	>	else if (counterBusy == 0 &&
2193	>	U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
2194	>	try {
2195	>	if (counterCells == as) {// Expand table unless stale
2196	>	CounterCell[] rs = new CounterCell[n << 1];
2197	>	for (int i = 0; i < n; ++i)
2198	>	rs[i] = as[i];
2199	>	counterCells = rs;
2200	>	}
2201	>	} finally {
2202	>	counterBusy = 0;
2203	>	}
2204	>	collide = false;
2205	>	continue;                   // Retry with expanded table
2206	>	}
2207	>	h ^= h << 13;                   // Rehash
2208	>	h ^= h >>> 17;
2209	>	h ^= h << 5;
2210	>	}
2211	>	else if (counterBusy == 0 && counterCells == as &&
2212	>	U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
2213	>	boolean init = false;
2214	>	try {                           // Initialize table
2215	>	if (counterCells == as) {
2216	>	CounterCell[] rs = new CounterCell[2];
2217	>	rs[h & 1] = new CounterCell(x);
2218	>	counterCells = rs;
2219	>	init = true;
2220	>	}
2221	>	} finally {
2222	>	counterBusy = 0;
2223	>	}
2224	>	if (init)
2225	>	break;
2226	>	}
2227	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2228	>	break;                          // Fall back on using base
2229	>	}
2230	>	hc.code = h;                            // Record index for next time
2231		}
2232
2233	+	/* ----------------Table Traversal -------------- */
2234	+
2235		/**
2236	<	* Returns the segment for the given index, creating it and
2237	<	* recording in segment table (via CAS) if not already present.
2238	<	*
2239	<	* @param k the index
2240	<	* @return the segment
2241	<	*/
2242	<	@SuppressWarnings("unchecked")
2243	<	private Segment<K,V> ensureSegment(int k) {
2244	<	final Segment<K,V>[] ss = this.segments;
2245	<	long u = (k << SSHIFT) + SBASE; // raw offset
2246	<	Segment<K,V> seg;
2247	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
2248	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
2249	<	int cap = proto.table.length;
2250	<	float lf = proto.loadFactor;
2251	<	int threshold = (int)(cap * lf);
2252	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry[cap];
2253	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2254	<	== null) { // recheck
2255	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
2256	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2257	<	== null) {
2258	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
2259	<	break;
2236	>	* Encapsulates traversal for methods such as containsValue; also
2237	>	* serves as a base class for other iterators and bulk tasks.
2238	>	*
2239	>	* At each step, the iterator snapshots the key ("nextKey") and
2240	>	* value ("nextVal") of a valid node (i.e., one that, at point of
2241	>	* snapshot, has a non-null user value). Because val fields can
2242	>	* change (including to null, indicating deletion), field nextVal
2243	>	* might not be accurate at point of use, but still maintains the
2244	>	* weak consistency property of holding a value that was once
2245	>	* valid. To support iterator.remove, the nextKey field is not
2246	>	* updated (nulled out) when the iterator cannot advance.
2247	>	*
2248	>	* Internal traversals directly access these fields, as in:
2249	>	* {@code while (it.advance() != null) { process(it.nextKey); }}
2250	>	*
2251	>	* Exported iterators must track whether the iterator has advanced
2252	>	* (in hasNext vs next) (by setting/checking/nulling field
2253	>	* nextVal), and then extract key, value, or key-value pairs as
2254	>	* return values of next().
2255	>	*
2256	>	* The iterator visits once each still-valid node that was
2257	>	* reachable upon iterator construction. It might miss some that
2258	>	* were added to a bin after the bin was visited, which is OK wrt
2259	>	* consistency guarantees. Maintaining this property in the face
2260	>	* of possible ongoing resizes requires a fair amount of
2261	>	* bookkeeping state that is difficult to optimize away amidst
2262	>	* volatile accesses.  Even so, traversal maintains reasonable
2263	>	* throughput.
2264	>	*
2265	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2266	>	* However, if the table has been resized, then all future steps
2267	>	* must traverse both the bin at the current index as well as at
2268	>	* (index + baseSize); and so on for further resizings. To
2269	>	* paranoically cope with potential sharing by users of iterators
2270	>	* across threads, iteration terminates if a bounds checks fails
2271	>	* for a table read.
2272	>	*
2273	>	* This class extends CountedCompleter to streamline parallel
2274	>	* iteration in bulk operations. This adds only a few fields of
2275	>	* space overhead, which is small enough in cases where it is not
2276	>	* needed to not worry about it.  Because CountedCompleter is
2277	>	* Serializable, but iterators need not be, we need to add warning
2278	>	* suppressions.
2279	>	*/
2280	>	@SuppressWarnings("serial") static class Traverser<K,V,R>
2281	>	extends CountedCompleter<R> {
2282	>	final ConcurrentHashMap<K, V> map;
2283	>	Node<V> next;        // the next entry to use
2284	>	Object nextKey;      // cached key field of next
2285	>	V nextVal;           // cached val field of next
2286	>	Node<V>[] tab;       // current table; updated if resized
2287	>	int index;           // index of bin to use next
2288	>	int baseIndex;       // current index of initial table
2289	>	int baseLimit;       // index bound for initial table
2290	>	int baseSize;        // initial table size
2291	>	int batch;           // split control
2292	>
2293	>	/** Creates iterator for all entries in the table. */
2294	>	Traverser(ConcurrentHashMap<K, V> map) {
2295	>	this.map = map;
2296	>	}
2297	>
2298	>	/** Creates iterator for split() methods and task constructors */
2299	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it, int batch) {
2300	>	super(it);
2301	>	this.batch = batch;
2302	>	if ((this.map = map) != null && it != null) { // split parent
2303	>	Node<V>[] t;
2304	>	if ((t = it.tab) == null &&
2305	>	(t = it.tab = map.table) != null)
2306	>	it.baseLimit = it.baseSize = t.length;
2307	>	this.tab = t;
2308	>	this.baseSize = it.baseSize;
2309	>	int hi = this.baseLimit = it.baseLimit;
2310	>	it.baseLimit = this.index = this.baseIndex =
2311	>	(hi + it.baseIndex + 1) >>> 1;
2312	>	}
2313	>	}
2314	>
2315	>	/**
2316	>	* Advances next; returns nextVal or null if terminated.
2317	>	* See above for explanation.
2318	>	*/
2319	>	@SuppressWarnings("unchecked") final V advance() {
2320	>	Node<V> e = next;
2321	>	V ev = null;
2322	>	outer: do {
2323	>	if (e != null)                  // advance past used/skipped node
2324	>	e = e.next;
2325	>	while (e == null) {             // get to next non-null bin
2326	>	ConcurrentHashMap<K, V> m;
2327	>	Node<V>[] t; int b, i, n; Object ek; //  must use locals
2328	>	if ((t = tab) != null)
2329	>	n = t.length;
2330	>	else if ((m = map) != null && (t = tab = m.table) != null)
2331	>	n = baseLimit = baseSize = t.length;
2332	>	else
2333	>	break outer;
2334	>	if ((b = baseIndex) >= baseLimit ||
2335	>	(i = index) < 0 || i >= n)
2336	>	break outer;
2337	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2338	>	if ((ek = e.key) instanceof TreeBin)
2339	>	e = ((TreeBin<V>)ek).first;
2340	>	else {
2341	>	tab = (Node<V>[])ek;
2342	>	continue;           // restarts due to null val
2343	>	}
2344	>	}                           // visit upper slots if present
2345	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2346	>	}
2347	>	nextKey = e.key;
2348	>	} while ((ev = e.val) == null);    // skip deleted or special nodes
2349	>	next = e;
2350	>	return nextVal = ev;
2351	>	}
2352	>
2353	>	public final void remove() {
2354	>	Object k = nextKey;
2355	>	if (k == null && (advance() == null || (k = nextKey) == null))
2356	>	throw new IllegalStateException();
2357	>	map.internalReplace(k, null, null);
2358	>	}
2359	>
2360	>	public final boolean hasNext() {
2361	>	return nextVal != null || advance() != null;
2362	>	}
2363	>
2364	>	public final boolean hasMoreElements() { return hasNext(); }
2365	>
2366	>	public void compute() { } // default no-op CountedCompleter body
2367	>
2368	>	/**
2369	>	* Returns a batch value > 0 if this task should (and must) be
2370	>	* split, if so, adding to pending count, and in any case
2371	>	* updating batch value. The initial batch value is approx
2372	>	* exp2 of the number of times (minus one) to split task by
2373	>	* two before executing leaf action. This value is faster to
2374	>	* compute and more convenient to use as a guide to splitting
2375	>	* than is the depth, since it is used while dividing by two
2376	>	* anyway.
2377	>	*/
2378	>	final int preSplit() {
2379	>	ConcurrentHashMap<K, V> m; int b; Node<V>[] t;  ForkJoinPool pool;
2380	>	if ((b = batch) < 0 && (m = map) != null) { // force initialization
2381	>	if ((t = tab) == null && (t = tab = m.table) != null)
2382	>	baseLimit = baseSize = t.length;
2383	>	if (t != null) {
2384	>	long n = m.sumCount();
2385	>	int par = ((pool = getPool()) == null) ?
2386	>	ForkJoinPool.getCommonPoolParallelism() :
2387	>	pool.getParallelism();
2388	>	int sp = par << 3; // slack of 8
2389	>	b = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
2390		}
2391		}
2392	+	b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
2393	+	if ((batch = b) > 0)
2394	+	addToPendingCount(1);
2395	+	return b;
2396		}
2397	<	return seg;
2397	>
2398		}
2399
2400	<	// Hash-based segment and entry accesses
2400	>	/* ---------------- Public operations -------------- */
2401
2402		/**
2403	<	* Gets the segment for the given hash code.
2403	>	* Creates a new, empty map with the default initial table size (16).
2404		*/
2405	<	@SuppressWarnings("unchecked")
671	<	private Segment<K,V> segmentForHash(int h) {
672	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
673	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
2405	>	public ConcurrentHashMap() {
2406		}
2407
2408		/**
2409	<	* Gets the table entry for the given segment and hash code.
2409	>	* Creates a new, empty map with an initial table size
2410	>	* accommodating the specified number of elements without the need
2411	>	* to dynamically resize.
2412	>	*
2413	>	* @param initialCapacity The implementation performs internal
2414	>	* sizing to accommodate this many elements.
2415	>	* @throws IllegalArgumentException if the initial capacity of
2416	>	* elements is negative
2417		*/
2418	<	@SuppressWarnings("unchecked")
2419	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
2420	<	HashEntry<K,V>[] tab;
2421	<	return (seg == null || (tab = seg.table) == null) ? null :
2422	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
2423	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2418	>	public ConcurrentHashMap(int initialCapacity) {
2419	>	if (initialCapacity < 0)
2420	>	throw new IllegalArgumentException();
2421	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2422	>	MAXIMUM_CAPACITY :
2423	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2424	>	this.sizeCtl = cap;
2425		}
2426
687	–	/* ---------------- Public operations -------------- */
688	–
2427		/**
2428	<	* Creates a new, empty map with the specified initial
691	<	* capacity, load factor and concurrency level.
2428	>	* Creates a new map with the same mappings as the given map.
2429		*
2430	<	* @param initialCapacity the initial capacity. The implementation
694	<	* performs internal sizing to accommodate this many elements.
695	<	* @param loadFactor  the load factor threshold, used to control resizing.
696	<	* Resizing may be performed when the average number of elements per
697	<	* bin exceeds this threshold.
698	<	* @param concurrencyLevel the estimated number of concurrently
699	<	* updating threads. The implementation performs internal sizing
700	<	* to try to accommodate this many threads.
701	<	* @throws IllegalArgumentException if the initial capacity is
702	<	* negative or the load factor or concurrencyLevel are
703	<	* nonpositive.
2430	>	* @param m the map
2431		*/
2432	<	@SuppressWarnings("unchecked")
2433	<	public ConcurrentHashMap(int initialCapacity,
2434	<	float loadFactor, int concurrencyLevel) {
708	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
709	<	throw new IllegalArgumentException();
710	<	if (concurrencyLevel > MAX_SEGMENTS)
711	<	concurrencyLevel = MAX_SEGMENTS;
712	<	// Find power-of-two sizes best matching arguments
713	<	int sshift = 0;
714	<	int ssize = 1;
715	<	while (ssize < concurrencyLevel) {
716	<	++sshift;
717	<	ssize <<= 1;
718	<	}
719	<	this.segmentShift = 32 - sshift;
720	<	this.segmentMask = ssize - 1;
721	<	if (initialCapacity > MAXIMUM_CAPACITY)
722	<	initialCapacity = MAXIMUM_CAPACITY;
723	<	int c = initialCapacity / ssize;
724	<	if (c * ssize < initialCapacity)
725	<	++c;
726	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
727	<	while (cap < c)
728	<	cap <<= 1;
729	<	// create segments and segments[0]
730	<	Segment<K,V> s0 =
731	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
732	<	(HashEntry<K,V>[])new HashEntry[cap]);
733	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment[ssize];
734	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
735	<	this.segments = ss;
2432	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2433	>	this.sizeCtl = DEFAULT_CAPACITY;
2434	>	internalPutAll(m);
2435		}
2436
2437		/**
2438	<	* Creates a new, empty map with the specified initial capacity
2439	<	* and load factor and with the default concurrencyLevel (16).
2438	>	* Creates a new, empty map with an initial table size based on
2439	>	* the given number of elements ({@code initialCapacity}) and
2440	>	* initial table density ({@code loadFactor}).
2441		*
2442	<	* @param initialCapacity The implementation performs internal
2443	<	* sizing to accommodate this many elements.
2444	<	* @param loadFactor  the load factor threshold, used to control resizing.
2445	<	* Resizing may be performed when the average number of elements per
2446	<	* bin exceeds this threshold.
2442	>	* @param initialCapacity the initial capacity. The implementation
2443	>	* performs internal sizing to accommodate this many elements,
2444	>	* given the specified load factor.
2445	>	* @param loadFactor the load factor (table density) for
2446	>	* establishing the initial table size
2447		* @throws IllegalArgumentException if the initial capacity of
2448		* elements is negative or the load factor is nonpositive
2449		*
2450		* @since 1.6
2451		*/
2452		public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2453	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2453	>	this(initialCapacity, loadFactor, 1);
2454		}
2455
2456		/**
2457	<	* Creates a new, empty map with the specified initial capacity,
2458	<	* and with default load factor (0.75) and concurrencyLevel (16).
2457	>	* Creates a new, empty map with an initial table size based on
2458	>	* the given number of elements ({@code initialCapacity}), table
2459	>	* density ({@code loadFactor}), and number of concurrently
2460	>	* updating threads ({@code concurrencyLevel}).
2461		*
2462		* @param initialCapacity the initial capacity. The implementation
2463	<	* performs internal sizing to accommodate this many elements.
2464	<	* @throws IllegalArgumentException if the initial capacity of
2465	<	* elements is negative.
2463	>	* performs internal sizing to accommodate this many elements,
2464	>	* given the specified load factor.
2465	>	* @param loadFactor the load factor (table density) for
2466	>	* establishing the initial table size
2467	>	* @param concurrencyLevel the estimated number of concurrently
2468	>	* updating threads. The implementation may use this value as
2469	>	* a sizing hint.
2470	>	* @throws IllegalArgumentException if the initial capacity is
2471	>	* negative or the load factor or concurrencyLevel are
2472	>	* nonpositive
2473		*/
2474	<	public ConcurrentHashMap(int initialCapacity) {
2475	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2474	>	public ConcurrentHashMap(int initialCapacity,
2475	>	float loadFactor, int concurrencyLevel) {
2476	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2477	>	throw new IllegalArgumentException();
2478	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2479	>	initialCapacity = concurrencyLevel;   // as estimated threads
2480	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2481	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2482	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
2483	>	this.sizeCtl = cap;
2484		}
2485
2486		/**
2487	<	* Creates a new, empty map with a default initial capacity (16),
2488	<	* load factor (0.75) and concurrencyLevel (16).
2487	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2488	>	* from the given type to {@code Boolean.TRUE}.
2489	>	*
2490	>	* @return the new set
2491		*/
2492	<	public ConcurrentHashMap() {
2493	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2492	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2493	>	return new KeySetView<K,Boolean>(new ConcurrentHashMap<K,Boolean>(),
2494	>	Boolean.TRUE);
2495		}
2496
2497		/**
2498	<	* Creates a new map with the same mappings as the given map.
2499	<	* The map is created with a capacity of 1.5 times the number
780	<	* of mappings in the given map or 16 (whichever is greater),
781	<	* and a default load factor (0.75) and concurrencyLevel (16).
2498	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2499	>	* from the given type to {@code Boolean.TRUE}.
2500		*
2501	<	* @param m the map
2501	>	* @param initialCapacity The implementation performs internal
2502	>	* sizing to accommodate this many elements.
2503	>	* @throws IllegalArgumentException if the initial capacity of
2504	>	* elements is negative
2505	>	* @return the new set
2506		*/
2507	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2508	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
2509	<	DEFAULT_INITIAL_CAPACITY),
788	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
789	<	putAll(m);
2507	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2508	>	return new KeySetView<K,Boolean>
2509	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2510		}
2511
2512		/**
2513	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
794	<	*
795	<	* @return <tt>true</tt> if this map contains no key-value mappings
2513	>	* {@inheritDoc}
2514		*/
2515		public boolean isEmpty() {
2516	<	/*
799	<	* Sum per-segment modCounts to avoid mis-reporting when
800	<	* elements are concurrently added and removed in one segment
801	<	* while checking another, in which case the table was never
802	<	* actually empty at any point. (The sum ensures accuracy up
803	<	* through at least 1<<31 per-segment modifications before
804	<	* recheck.)  Methods size() and containsValue() use similar
805	<	* constructions for stability checks.
806	<	*/
807	<	long sum = 0L;
808	<	final Segment<K,V>[] segments = this.segments;
809	<	for (int j = 0; j < segments.length; ++j) {
810	<	Segment<K,V> seg = segmentAt(segments, j);
811	<	if (seg != null) {
812	<	if (seg.count != 0)
813	<	return false;
814	<	sum += seg.modCount;
815	<	}
816	<	}
817	<	if (sum != 0L) { // recheck unless no modifications
818	<	for (int j = 0; j < segments.length; ++j) {
819	<	Segment<K,V> seg = segmentAt(segments, j);
820	<	if (seg != null) {
821	<	if (seg.count != 0)
822	<	return false;
823	<	sum -= seg.modCount;
824	<	}
825	<	}
826	<	if (sum != 0L)
827	<	return false;
828	<	}
829	<	return true;
2516	>	return sumCount() <= 0L; // ignore transient negative values
2517		}
2518
2519		/**
2520	<	* Returns the number of key-value mappings in this map.  If the
834	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
835	<	* <tt>Integer.MAX_VALUE</tt>.
836	<	*
837	<	* @return the number of key-value mappings in this map
2520	>	* {@inheritDoc}
2521		*/
2522		public int size() {
2523	<	// Try a few times to get accurate count. On failure due to
2524	<	// continuous async changes in table, resort to locking.
2525	<	final Segment<K,V>[] segments = this.segments;
2526	<	int size;
2527	<	boolean overflow; // true if size overflows 32 bits
2528	<	long sum;         // sum of modCounts
2529	<	long last = 0L;   // previous sum
2530	<	int retries = -1; // first iteration isn't retry
2531	<	try {
2532	<	for (;;) {
2533	<	if (retries++ == RETRIES_BEFORE_LOCK) {
2534	<	for (int j = 0; j < segments.length; ++j)
2535	<	ensureSegment(j).lock(); // force creation
2536	<	}
2537	<	sum = 0L;
2538	<	size = 0;
2539	<	overflow = false;
2540	<	for (int j = 0; j < segments.length; ++j) {
858	<	Segment<K,V> seg = segmentAt(segments, j);
859	<	if (seg != null) {
860	<	sum += seg.modCount;
861	<	int c = seg.count;
862	<	if (c < 0 || (size += c) < 0)
863	<	overflow = true;
864	<	}
865	<	}
866	<	if (sum == last)
867	<	break;
868	<	last = sum;
869	<	}
870	<	} finally {
871	<	if (retries > RETRIES_BEFORE_LOCK) {
872	<	for (int j = 0; j < segments.length; ++j)
873	<	segmentAt(segments, j).unlock();
874	<	}
875	<	}
876	<	return overflow ? Integer.MAX_VALUE : size;
2523	>	long n = sumCount();
2524	>	return ((n < 0L) ? 0 :
2525	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2526	>	(int)n);
2527	>	}
2528	>
2529	>	/**
2530	>	* Returns the number of mappings. This method should be used
2531	>	* instead of {@link #size} because a ConcurrentHashMap may
2532	>	* contain more mappings than can be represented as an int. The
2533	>	* value returned is an estimate; the actual count may differ if
2534	>	* there are concurrent insertions or removals.
2535	>	*
2536	>	* @return the number of mappings
2537	>	*/
2538	>	public long mappingCount() {
2539	>	long n = sumCount();
2540	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2541		}
2542
2543		/**
#	Line 888 | Line 2552 | public class ConcurrentHashMap<K, V> ext
2552		* @throws NullPointerException if the specified key is null
2553		*/
2554		public V get(Object key) {
2555	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
2556	<	HashEntry<K,V>[] tab;
2557	<	int h = hash(key.hashCode());
2558	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2559	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
2560	<	(tab = s.table) != null) {
2561	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
2562	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2563	<	e != null; e = e.next) {
2564	<	K k;
2565	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
2566	<	return e.value;
2567	<	}
2568	<	}
2569	<	return null;
2555	>	return internalGet(key);
2556	>	}
2557	>
2558	>	/**
2559	>	* Returns the value to which the specified key is mapped,
2560	>	* or the given defaultValue if this map contains no mapping for the key.
2561	>	*
2562	>	* @param key the key
2563	>	* @param defaultValue the value to return if this map contains
2564	>	* no mapping for the given key
2565	>	* @return the mapping for the key, if present; else the defaultValue
2566	>	* @throws NullPointerException if the specified key is null
2567	>	*/
2568	>	public V getValueOrDefault(Object key, V defaultValue) {
2569	>	V v;
2570	>	return (v = internalGet(key)) == null ? defaultValue : v;
2571		}
2572
2573		/**
2574		* Tests if the specified object is a key in this table.
2575		*
2576		* @param  key   possible key
2577	<	* @return <tt>true</tt> if and only if the specified object
2577	>	* @return {@code true} if and only if the specified object
2578		*         is a key in this table, as determined by the
2579	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
2579	>	*         {@code equals} method; {@code false} otherwise
2580		* @throws NullPointerException if the specified key is null
2581		*/
917	–	@SuppressWarnings("unchecked")
2582		public boolean containsKey(Object key) {
2583	<	Segment<K,V> s; // same as get() except no need for volatile value read
920	<	HashEntry<K,V>[] tab;
921	<	int h = hash(key.hashCode());
922	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
923	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
924	<	(tab = s.table) != null) {
925	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
926	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
927	<	e != null; e = e.next) {
928	<	K k;
929	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
930	<	return true;
931	<	}
932	<	}
933	<	return false;
2583	>	return internalGet(key) != null;
2584		}
2585
2586		/**
2587	<	* Returns <tt>true</tt> if this map maps one or more keys to the
2588	<	* specified value. Note: This method requires a full internal
2589	<	* traversal of the hash table, and so is much slower than
940	<	* method <tt>containsKey</tt>.
2587	>	* Returns {@code true} if this map maps one or more keys to the
2588	>	* specified value. Note: This method may require a full traversal
2589	>	* of the map, and is much slower than method {@code containsKey}.
2590		*
2591		* @param value value whose presence in this map is to be tested
2592	<	* @return <tt>true</tt> if this map maps one or more keys to the
2592	>	* @return {@code true} if this map maps one or more keys to the
2593		*         specified value
2594		* @throws NullPointerException if the specified value is null
2595		*/
2596		public boolean containsValue(Object value) {
948	–	// Same idea as size()
2597		if (value == null)
2598		throw new NullPointerException();
2599	<	final Segment<K,V>[] segments = this.segments;
2600	<	boolean found = false;
2601	<	long last = 0L;   // previous sum
2602	<	int retries = -1;
2603	<	try {
956	<	outer: for (;;) {
957	<	if (retries++ == RETRIES_BEFORE_LOCK) {
958	<	for (int j = 0; j < segments.length; ++j)
959	<	ensureSegment(j).lock(); // force creation
960	<	}
961	<	long sum = 0L;
962	<	for (int j = 0; j < segments.length; ++j) {
963	<	HashEntry<K,V>[] tab;
964	<	Segment<K,V> seg = segmentAt(segments, j);
965	<	if (seg != null && (tab = seg.table) != null) {
966	<	for (int i = 0 ; i < tab.length; i++) {
967	<	HashEntry<K,V> e;
968	<	for (e = entryAt(tab, i); e != null; e = e.next) {
969	<	V v = e.value;
970	<	if (v != null && value.equals(v)) {
971	<	found = true;
972	<	break outer;
973	<	}
974	<	}
975	<	}
976	<	sum += seg.modCount;
977	<	}
978	<	}
979	<	if (retries > 0 && sum == last)
980	<	break;
981	<	last = sum;
982	<	}
983	<	} finally {
984	<	if (retries > RETRIES_BEFORE_LOCK) {
985	<	for (int j = 0; j < segments.length; ++j)
986	<	segmentAt(segments, j).unlock();
987	<	}
2599	>	V v;
2600	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2601	>	while ((v = it.advance()) != null) {
2602	>	if (v == value || value.equals(v))
2603	>	return true;
2604		}
2605	<	return found;
2605	>	return false;
2606		}
2607
2608		/**
#	Line 998 | Line 2614 | public class ConcurrentHashMap<K, V> ext
2614		* Java Collections framework.
2615		*
2616		* @param  value a value to search for
2617	<	* @return <tt>true</tt> if and only if some key maps to the
2618	<	*         <tt>value</tt> argument in this table as
2619	<	*         determined by the <tt>equals</tt> method;
2620	<	*         <tt>false</tt> otherwise
2617	>	* @return {@code true} if and only if some key maps to the
2618	>	*         {@code value} argument in this table as
2619	>	*         determined by the {@code equals} method;
2620	>	*         {@code false} otherwise
2621		* @throws NullPointerException if the specified value is null
2622		*/
2623	<	public boolean contains(Object value) {
2623	>	@Deprecated public boolean contains(Object value) {
2624		return containsValue(value);
2625		}
2626
#	Line 1012 | Line 2628 | public class ConcurrentHashMap<K, V> ext
2628		* Maps the specified key to the specified value in this table.
2629		* Neither the key nor the value can be null.
2630		*
2631	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
2631	>	* <p>The value can be retrieved by calling the {@code get} method
2632		* with a key that is equal to the original key.
2633		*
2634		* @param key key with which the specified value is to be associated
2635		* @param value value to be associated with the specified key
2636	<	* @return the previous value associated with <tt>key</tt>, or
2637	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2636	>	* @return the previous value associated with {@code key}, or
2637	>	*         {@code null} if there was no mapping for {@code key}
2638		* @throws NullPointerException if the specified key or value is null
2639		*/
1024	–	@SuppressWarnings("unchecked")
2640		public V put(K key, V value) {
2641	<	Segment<K,V> s;
1027	<	if (value == null)
1028	<	throw new NullPointerException();
1029	<	int hash = hash(key.hashCode());
1030	<	int j = (hash >>> segmentShift) & segmentMask;
1031	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1032	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1033	<	s = ensureSegment(j);
1034	<	return s.put(key, hash, value, false);
2641	>	return internalPut(key, value, false);
2642		}
2643
2644		/**
2645		* {@inheritDoc}
2646		*
2647		* @return the previous value associated with the specified key,
2648	<	*         or <tt>null</tt> if there was no mapping for the key
2648	>	*         or {@code null} if there was no mapping for the key
2649		* @throws NullPointerException if the specified key or value is null
2650		*/
1044	–	@SuppressWarnings("unchecked")
2651		public V putIfAbsent(K key, V value) {
2652	<	Segment<K,V> s;
1047	<	if (value == null)
1048	<	throw new NullPointerException();
1049	<	int hash = hash(key.hashCode());
1050	<	int j = (hash >>> segmentShift) & segmentMask;
1051	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1052	<	(segments, (j << SSHIFT) + SBASE)) == null)
1053	<	s = ensureSegment(j);
1054	<	return s.put(key, hash, value, true);
2652	>	return internalPut(key, value, true);
2653		}
2654
2655		/**
#	Line 1062 | Line 2660 | public class ConcurrentHashMap<K, V> ext
2660		* @param m mappings to be stored in this map
2661		*/
2662		public void putAll(Map<? extends K, ? extends V> m) {
2663	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2664	<	put(e.getKey(), e.getValue());
2663	>	internalPutAll(m);
2664	>	}
2665	>
2666	>	/**
2667	>	* If the specified key is not already associated with a value,
2668	>	* computes its value using the given mappingFunction and enters
2669	>	* it into the map unless null.  This is equivalent to
2670	>	* <pre> {@code
2671	>	* if (map.containsKey(key))
2672	>	*   return map.get(key);
2673	>	* value = mappingFunction.apply(key);
2674	>	* if (value != null)
2675	>	*   map.put(key, value);
2676	>	* return value;}</pre>
2677	>	*
2678	>	* except that the action is performed atomically.  If the
2679	>	* function returns {@code null} no mapping is recorded. If the
2680	>	* function itself throws an (unchecked) exception, the exception
2681	>	* is rethrown to its caller, and no mapping is recorded.  Some
2682	>	* attempted update operations on this map by other threads may be
2683	>	* blocked while computation is in progress, so the computation
2684	>	* should be short and simple, and must not attempt to update any
2685	>	* other mappings of this Map. The most appropriate usage is to
2686	>	* construct a new object serving as an initial mapped value, or
2687	>	* memoized result, as in:
2688	>	*
2689	>	*  <pre> {@code
2690	>	* map.computeIfAbsent(key, new Fun<K, V>() {
2691	>	*   public V map(K k) { return new Value(f(k)); }});}</pre>
2692	>	*
2693	>	* @param key key with which the specified value is to be associated
2694	>	* @param mappingFunction the function to compute a value
2695	>	* @return the current (existing or computed) value associated with
2696	>	*         the specified key, or null if the computed value is null
2697	>	* @throws NullPointerException if the specified key or mappingFunction
2698	>	*         is null
2699	>	* @throws IllegalStateException if the computation detectably
2700	>	*         attempts a recursive update to this map that would
2701	>	*         otherwise never complete
2702	>	* @throws RuntimeException or Error if the mappingFunction does so,
2703	>	*         in which case the mapping is left unestablished
2704	>	*/
2705	>	public V computeIfAbsent
2706	>	(K key, Fun<? super K, ? extends V> mappingFunction) {
2707	>	return internalComputeIfAbsent(key, mappingFunction);
2708	>	}
2709	>
2710	>	/**
2711	>	* If the given key is present, computes a new mapping value given a key and
2712	>	* its current mapped value. This is equivalent to
2713	>	*  <pre> {@code
2714	>	*   if (map.containsKey(key)) {
2715	>	*     value = remappingFunction.apply(key, map.get(key));
2716	>	*     if (value != null)
2717	>	*       map.put(key, value);
2718	>	*     else
2719	>	*       map.remove(key);
2720	>	*   }
2721	>	* }</pre>
2722	>	*
2723	>	* except that the action is performed atomically.  If the
2724	>	* function returns {@code null}, the mapping is removed.  If the
2725	>	* function itself throws an (unchecked) exception, the exception
2726	>	* is rethrown to its caller, and the current mapping is left
2727	>	* unchanged.  Some attempted update operations on this map by
2728	>	* other threads may be blocked while computation is in progress,
2729	>	* so the computation should be short and simple, and must not
2730	>	* attempt to update any other mappings of this Map. For example,
2731	>	* to either create or append new messages to a value mapping:
2732	>	*
2733	>	* @param key key with which the specified value is to be associated
2734	>	* @param remappingFunction the function to compute a value
2735	>	* @return the new value associated with the specified key, or null if none
2736	>	* @throws NullPointerException if the specified key or remappingFunction
2737	>	*         is null
2738	>	* @throws IllegalStateException if the computation detectably
2739	>	*         attempts a recursive update to this map that would
2740	>	*         otherwise never complete
2741	>	* @throws RuntimeException or Error if the remappingFunction does so,
2742	>	*         in which case the mapping is unchanged
2743	>	*/
2744	>	public V computeIfPresent
2745	>	(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2746	>	return internalCompute(key, true, remappingFunction);
2747	>	}
2748	>
2749	>	/**
2750	>	* Computes a new mapping value given a key and
2751	>	* its current mapped value (or {@code null} if there is no current
2752	>	* mapping). This is equivalent to
2753	>	*  <pre> {@code
2754	>	*   value = remappingFunction.apply(key, map.get(key));
2755	>	*   if (value != null)
2756	>	*     map.put(key, value);
2757	>	*   else
2758	>	*     map.remove(key);
2759	>	* }</pre>
2760	>	*
2761	>	* except that the action is performed atomically.  If the
2762	>	* function returns {@code null}, the mapping is removed.  If the
2763	>	* function itself throws an (unchecked) exception, the exception
2764	>	* is rethrown to its caller, and the current mapping is left
2765	>	* unchanged.  Some attempted update operations on this map by
2766	>	* other threads may be blocked while computation is in progress,
2767	>	* so the computation should be short and simple, and must not
2768	>	* attempt to update any other mappings of this Map. For example,
2769	>	* to either create or append new messages to a value mapping:
2770	>	*
2771	>	* <pre> {@code
2772	>	* Map<Key, String> map = ...;
2773	>	* final String msg = ...;
2774	>	* map.compute(key, new BiFun<Key, String, String>() {
2775	>	*   public String apply(Key k, String v) {
2776	>	*    return (v == null) ? msg : v + msg;});}}</pre>
2777	>	*
2778	>	* @param key key with which the specified value is to be associated
2779	>	* @param remappingFunction the function to compute a value
2780	>	* @return the new value associated with the specified key, or null if none
2781	>	* @throws NullPointerException if the specified key or remappingFunction
2782	>	*         is null
2783	>	* @throws IllegalStateException if the computation detectably
2784	>	*         attempts a recursive update to this map that would
2785	>	*         otherwise never complete
2786	>	* @throws RuntimeException or Error if the remappingFunction does so,
2787	>	*         in which case the mapping is unchanged
2788	>	*/
2789	>	public V compute
2790	>	(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
2791	>	return internalCompute(key, false, remappingFunction);
2792	>	}
2793	>
2794	>	/**
2795	>	* If the specified key is not already associated
2796	>	* with a value, associate it with the given value.
2797	>	* Otherwise, replace the value with the results of
2798	>	* the given remapping function. This is equivalent to:
2799	>	*  <pre> {@code
2800	>	*   if (!map.containsKey(key))
2801	>	*     map.put(value);
2802	>	*   else {
2803	>	*     newValue = remappingFunction.apply(map.get(key), value);
2804	>	*     if (value != null)
2805	>	*       map.put(key, value);
2806	>	*     else
2807	>	*       map.remove(key);
2808	>	*   }
2809	>	* }</pre>
2810	>	* except that the action is performed atomically.  If the
2811	>	* function returns {@code null}, the mapping is removed.  If the
2812	>	* function itself throws an (unchecked) exception, the exception
2813	>	* is rethrown to its caller, and the current mapping is left
2814	>	* unchanged.  Some attempted update operations on this map by
2815	>	* other threads may be blocked while computation is in progress,
2816	>	* so the computation should be short and simple, and must not
2817	>	* attempt to update any other mappings of this Map.
2818	>	*/
2819	>	public V merge
2820	>	(K key, V value,
2821	>	BiFun<? super V, ? super V, ? extends V> remappingFunction) {
2822	>	return internalMerge(key, value, remappingFunction);
2823		}
2824
2825		/**
#	Line 1071 | Line 2827 | public class ConcurrentHashMap<K, V> ext
2827		* This method does nothing if the key is not in the map.
2828		*
2829		* @param  key the key that needs to be removed
2830	<	* @return the previous value associated with <tt>key</tt>, or
2831	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2830	>	* @return the previous value associated with {@code key}, or
2831	>	*         {@code null} if there was no mapping for {@code key}
2832		* @throws NullPointerException if the specified key is null
2833		*/
2834		public V remove(Object key) {
2835	<	int hash = hash(key.hashCode());
1080	<	Segment<K,V> s = segmentForHash(hash);
1081	<	return s == null ? null : s.remove(key, hash, null);
2835	>	return internalReplace(key, null, null);
2836		}
2837
2838		/**
#	Line 1087 | Line 2841 | public class ConcurrentHashMap<K, V> ext
2841		* @throws NullPointerException if the specified key is null
2842		*/
2843		public boolean remove(Object key, Object value) {
2844	<	int hash = hash(key.hashCode());
1091	<	Segment<K,V> s;
1092	<	return value != null && (s = segmentForHash(hash)) != null &&
1093	<	s.remove(key, hash, value) != null;
2844	>	return value != null && internalReplace(key, null, value) != null;
2845		}
2846
2847		/**
#	Line 1099 | Line 2850 | public class ConcurrentHashMap<K, V> ext
2850		* @throws NullPointerException if any of the arguments are null
2851		*/
2852		public boolean replace(K key, V oldValue, V newValue) {
2853	<	int hash = hash(key.hashCode());
1103	<	if (oldValue == null || newValue == null)
2853	>	if (key == null || oldValue == null || newValue == null)
2854		throw new NullPointerException();
2855	<	Segment<K,V> s = segmentForHash(hash);
1106	<	return s != null && s.replace(key, hash, oldValue, newValue);
2855	>	return internalReplace(key, newValue, oldValue) != null;
2856		}
2857
2858		/**
2859		* {@inheritDoc}
2860		*
2861		* @return the previous value associated with the specified key,
2862	<	*         or <tt>null</tt> if there was no mapping for the key
2862	>	*         or {@code null} if there was no mapping for the key
2863		* @throws NullPointerException if the specified key or value is null
2864		*/
2865		public V replace(K key, V value) {
2866	<	int hash = hash(key.hashCode());
1118	<	if (value == null)
2866	>	if (key == null || value == null)
2867		throw new NullPointerException();
2868	<	Segment<K,V> s = segmentForHash(hash);
1121	<	return s == null ? null : s.replace(key, hash, value);
2868	>	return internalReplace(key, value, null);
2869		}
2870
2871		/**
2872		* Removes all of the mappings from this map.
2873		*/
2874		public void clear() {
2875	<	final Segment<K,V>[] segments = this.segments;
1129	<	for (int j = 0; j < segments.length; ++j) {
1130	<	Segment<K,V> s = segmentAt(segments, j);
1131	<	if (s != null)
1132	<	s.clear();
1133	<	}
2875	>	internalClear();
2876		}
2877
2878		/**
2879		* Returns a {@link Set} view of the keys contained in this map.
2880		* The set is backed by the map, so changes to the map are
2881	<	* reflected in the set, and vice-versa.  The set supports element
1140	<	* removal, which removes the corresponding mapping from this map,
1141	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1142	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1143	<	* operations.  It does not support the <tt>add</tt> or
1144	<	* <tt>addAll</tt> operations.
2881	>	* reflected in the set, and vice-versa.
2882		*
2883	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1147	<	* that will never throw {@link ConcurrentModificationException},
1148	<	* and guarantees to traverse elements as they existed upon
1149	<	* construction of the iterator, and may (but is not guaranteed to)
1150	<	* reflect any modifications subsequent to construction.
2883	>	* @return the set view
2884		*/
2885	<	public Set<K> keySet() {
2886	<	Set<K> ks = keySet;
2887	<	return (ks != null) ? ks : (keySet = new KeySet());
2885	>	public KeySetView<K,V> keySet() {
2886	>	KeySetView<K,V> ks = keySet;
2887	>	return (ks != null) ? ks : (keySet = new KeySetView<K,V>(this, null));
2888	>	}
2889	>
2890	>	/**
2891	>	* Returns a {@link Set} view of the keys in this map, using the
2892	>	* given common mapped value for any additions (i.e., {@link
2893	>	* Collection#add} and {@link Collection#addAll}). This is of
2894	>	* course only appropriate if it is acceptable to use the same
2895	>	* value for all additions from this view.
2896	>	*
2897	>	* @param mappedValue the mapped value to use for any
2898	>	* additions.
2899	>	* @return the set view
2900	>	* @throws NullPointerException if the mappedValue is null
2901	>	*/
2902	>	public KeySetView<K,V> keySet(V mappedValue) {
2903	>	if (mappedValue == null)
2904	>	throw new NullPointerException();
2905	>	return new KeySetView<K,V>(this, mappedValue);
2906		}
2907
2908		/**
2909		* Returns a {@link Collection} view of the values contained in this map.
2910		* The collection is backed by the map, so changes to the map are
2911	<	* reflected in the collection, and vice-versa.  The collection
1161	<	* supports element removal, which removes the corresponding
1162	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1163	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
1164	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
1165	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
1166	<	*
1167	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1168	<	* that will never throw {@link ConcurrentModificationException},
1169	<	* and guarantees to traverse elements as they existed upon
1170	<	* construction of the iterator, and may (but is not guaranteed to)
1171	<	* reflect any modifications subsequent to construction.
2911	>	* reflected in the collection, and vice-versa.
2912		*/
2913	<	public Collection<V> values() {
2914	<	Collection<V> vs = values;
2915	<	return (vs != null) ? vs : (values = new Values());
2913	>	public ValuesView<K,V> values() {
2914	>	ValuesView<K,V> vs = values;
2915	>	return (vs != null) ? vs : (values = new ValuesView<K,V>(this));
2916		}
2917
2918		/**
#	Line 1180 | Line 2920 | public class ConcurrentHashMap<K, V> ext
2920		* The set is backed by the map, so changes to the map are
2921		* reflected in the set, and vice-versa.  The set supports element
2922		* removal, which removes the corresponding mapping from the map,
2923	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2924	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2925	<	* operations.  It does not support the <tt>add</tt> or
2926	<	* <tt>addAll</tt> operations.
2923	>	* via the {@code Iterator.remove}, {@code Set.remove},
2924	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2925	>	* operations.  It does not support the {@code add} or
2926	>	* {@code addAll} operations.
2927		*
2928	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2928	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2929		* that will never throw {@link ConcurrentModificationException},
2930		* and guarantees to traverse elements as they existed upon
2931		* construction of the iterator, and may (but is not guaranteed to)
2932		* reflect any modifications subsequent to construction.
2933		*/
2934		public Set<Map.Entry<K,V>> entrySet() {
2935	<	Set<Map.Entry<K,V>> es = entrySet;
2936	<	return (es != null) ? es : (entrySet = new EntrySet());
2935	>	EntrySetView<K,V> es = entrySet;
2936	>	return (es != null) ? es : (entrySet = new EntrySetView<K,V>(this));
2937		}
2938
2939		/**
#	Line 1203 | Line 2943 | public class ConcurrentHashMap<K, V> ext
2943		* @see #keySet()
2944		*/
2945		public Enumeration<K> keys() {
2946	<	return new KeyIterator();
2946	>	return new KeyIterator<K,V>(this);
2947		}
2948
2949		/**
#	Line 1213 | Line 2953 | public class ConcurrentHashMap<K, V> ext
2953		* @see #values()
2954		*/
2955		public Enumeration<V> elements() {
2956	<	return new ValueIterator();
2956	>	return new ValueIterator<K,V>(this);
2957		}
2958
2959	<	/* ---------------- Iterator Support -------------- */
2959	>	/**
2960	>	* Returns a partitionable iterator of the keys in this map.
2961	>	*
2962	>	* @return a partitionable iterator of the keys in this map
2963	>	*/
2964	>	public Spliterator<K> keySpliterator() {
2965	>	return new KeyIterator<K,V>(this);
2966	>	}
2967
2968	<	abstract class HashIterator {
2969	<	int nextSegmentIndex;
2970	<	int nextTableIndex;
2971	<	HashEntry<K,V>[] currentTable;
2972	<	HashEntry<K, V> nextEntry;
2973	<	HashEntry<K, V> lastReturned;
2968	>	/**
2969	>	* Returns a partitionable iterator of the values in this map.
2970	>	*
2971	>	* @return a partitionable iterator of the values in this map
2972	>	*/
2973	>	public Spliterator<V> valueSpliterator() {
2974	>	return new ValueIterator<K,V>(this);
2975	>	}
2976
2977	<	HashIterator() {
2978	<	nextSegmentIndex = segments.length - 1;
2979	<	nextTableIndex = -1;
2980	<	advance();
2981	<	}
2977	>	/**
2978	>	* Returns a partitionable iterator of the entries in this map.
2979	>	*
2980	>	* @return a partitionable iterator of the entries in this map
2981	>	*/
2982	>	public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2983	>	return new EntryIterator<K,V>(this);
2984	>	}
2985
2986	<	/**
2987	<	* Sets nextEntry to first node of next non-empty table
2988	<	* (in backwards order, to simplify checks).
2989	<	*/
2990	<	final void advance() {
2986	>	/**
2987	>	* Returns the hash code value for this {@link Map}, i.e.,
2988	>	* the sum of, for each key-value pair in the map,
2989	>	* {@code key.hashCode() ^ value.hashCode()}.
2990	>	*
2991	>	* @return the hash code value for this map
2992	>	*/
2993	>	public int hashCode() {
2994	>	int h = 0;
2995	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2996	>	V v;
2997	>	while ((v = it.advance()) != null) {
2998	>	h += it.nextKey.hashCode() ^ v.hashCode();
2999	>	}
3000	>	return h;
3001	>	}
3002	>
3003	>	/**
3004	>	* Returns a string representation of this map.  The string
3005	>	* representation consists of a list of key-value mappings (in no
3006	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
3007	>	* mappings are separated by the characters {@code ", "} (comma
3008	>	* and space).  Each key-value mapping is rendered as the key
3009	>	* followed by an equals sign ("{@code =}") followed by the
3010	>	* associated value.
3011	>	*
3012	>	* @return a string representation of this map
3013	>	*/
3014	>	public String toString() {
3015	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3016	>	StringBuilder sb = new StringBuilder();
3017	>	sb.append('{');
3018	>	V v;
3019	>	if ((v = it.advance()) != null) {
3020		for (;;) {
3021	<	if (nextTableIndex >= 0) {
3022	<	if ((nextEntry = entryAt(currentTable,
3023	<	nextTableIndex--)) != null)
3024	<	break;
3025	<	}
1245	<	else if (nextSegmentIndex >= 0) {
1246	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
1247	<	if (seg != null && (currentTable = seg.table) != null)
1248	<	nextTableIndex = currentTable.length - 1;
1249	<	}
1250	<	else
3021	>	Object k = it.nextKey;
3022	>	sb.append(k == this ? "(this Map)" : k);
3023	>	sb.append('=');
3024	>	sb.append(v == this ? "(this Map)" : v);
3025	>	if ((v = it.advance()) == null)
3026		break;
3027	+	sb.append(',').append(' ');
3028		}
3029		}
3030	+	return sb.append('}').toString();
3031	+	}
3032
3033	<	final HashEntry<K,V> nextEntry() {
3034	<	HashEntry<K,V> e = nextEntry;
3035	<	if (e == null)
3036	<	throw new NoSuchElementException();
3037	<	lastReturned = e; // cannot assign until after null check
3038	<	if ((nextEntry = e.next) == null)
3039	<	advance();
3040	<	return e;
3033	>	/**
3034	>	* Compares the specified object with this map for equality.
3035	>	* Returns {@code true} if the given object is a map with the same
3036	>	* mappings as this map.  This operation may return misleading
3037	>	* results if either map is concurrently modified during execution
3038	>	* of this method.
3039	>	*
3040	>	* @param o object to be compared for equality with this map
3041	>	* @return {@code true} if the specified object is equal to this map
3042	>	*/
3043	>	public boolean equals(Object o) {
3044	>	if (o != this) {
3045	>	if (!(o instanceof Map))
3046	>	return false;
3047	>	Map<?,?> m = (Map<?,?>) o;
3048	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3049	>	V val;
3050	>	while ((val = it.advance()) != null) {
3051	>	Object v = m.get(it.nextKey);
3052	>	if (v == null || (v != val && !v.equals(val)))
3053	>	return false;
3054	>	}
3055	>	for (Map.Entry<?,?> e : m.entrySet()) {
3056	>	Object mk, mv, v;
3057	>	if ((mk = e.getKey()) == null ||
3058	>	(mv = e.getValue()) == null ||
3059	>	(v = internalGet(mk)) == null ||
3060	>	(mv != v && !mv.equals(v)))
3061	>	return false;
3062	>	}
3063		}
3064	+	return true;
3065	+	}
3066
3067	<	public final boolean hasNext() { return nextEntry != null; }
1266	<	public final boolean hasMoreElements() { return nextEntry != null; }
3067	>	/* ----------------Iterators -------------- */
3068
3069	<	public final void remove() {
3070	<	if (lastReturned == null)
3069	>	@SuppressWarnings("serial") static final class KeyIterator<K,V>
3070	>	extends Traverser<K,V,Object>
3071	>	implements Spliterator<K>, Enumeration<K> {
3072	>	KeyIterator(ConcurrentHashMap<K, V> map) { super(map); }
3073	>	KeyIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
3074	>	super(map, it, -1);
3075	>	}
3076	>	public KeyIterator<K,V> split() {
3077	>	if (nextKey != null)
3078		throw new IllegalStateException();
3079	<	ConcurrentHashMap.this.remove(lastReturned.key);
3080	<	lastReturned = null;
3079	>	return new KeyIterator<K,V>(map, this);
3080	>	}
3081	>	@SuppressWarnings("unchecked") public final K next() {
3082	>	if (nextVal == null && advance() == null)
3083	>	throw new NoSuchElementException();
3084	>	Object k = nextKey;
3085	>	nextVal = null;
3086	>	return (K) k;
3087		}
3088	+
3089	+	public final K nextElement() { return next(); }
3090		}
3091
3092	<	final class KeyIterator
3093	<	extends HashIterator
3094	<	implements Iterator<K>, Enumeration<K>
3095	<	{
3096	<	public final K next()        { return super.nextEntry().key; }
3097	<	public final K nextElement() { return super.nextEntry().key; }
3092	>	@SuppressWarnings("serial") static final class ValueIterator<K,V>
3093	>	extends Traverser<K,V,Object>
3094	>	implements Spliterator<V>, Enumeration<V> {
3095	>	ValueIterator(ConcurrentHashMap<K, V> map) { super(map); }
3096	>	ValueIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
3097	>	super(map, it, -1);
3098	>	}
3099	>	public ValueIterator<K,V> split() {
3100	>	if (nextKey != null)
3101	>	throw new IllegalStateException();
3102	>	return new ValueIterator<K,V>(map, this);
3103	>	}
3104	>
3105	>	public final V next() {
3106	>	V v;
3107	>	if ((v = nextVal) == null && (v = advance()) == null)
3108	>	throw new NoSuchElementException();
3109	>	nextVal = null;
3110	>	return v;
3111	>	}
3112	>
3113	>	public final V nextElement() { return next(); }
3114		}
3115
3116	<	final class ValueIterator
3117	<	extends HashIterator
3118	<	implements Iterator<V>, Enumeration<V>
3119	<	{
3120	<	public final V next()        { return super.nextEntry().value; }
3121	<	public final V nextElement() { return super.nextEntry().value; }
3116	>	@SuppressWarnings("serial") static final class EntryIterator<K,V>
3117	>	extends Traverser<K,V,Object>
3118	>	implements Spliterator<Map.Entry<K,V>> {
3119	>	EntryIterator(ConcurrentHashMap<K, V> map) { super(map); }
3120	>	EntryIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
3121	>	super(map, it, -1);
3122	>	}
3123	>	public EntryIterator<K,V> split() {
3124	>	if (nextKey != null)
3125	>	throw new IllegalStateException();
3126	>	return new EntryIterator<K,V>(map, this);
3127	>	}
3128	>
3129	>	@SuppressWarnings("unchecked") public final Map.Entry<K,V> next() {
3130	>	V v;
3131	>	if ((v = nextVal) == null && (v = advance()) == null)
3132	>	throw new NoSuchElementException();
3133	>	Object k = nextKey;
3134	>	nextVal = null;
3135	>	return new MapEntry<K,V>((K)k, v, map);
3136	>	}
3137		}
3138
3139		/**
3140	<	* Custom Entry class used by EntryIterator.next(), that relays
1294	<	* setValue changes to the underlying map.
3140	>	* Exported Entry for iterators
3141		*/
3142	<	final class WriteThroughEntry
3143	<	extends AbstractMap.SimpleEntry<K,V>
3144	<	{
3145	<	WriteThroughEntry(K k, V v) {
3146	<	super(k,v);
3142	>	static final class MapEntry<K,V> implements Map.Entry<K, V> {
3143	>	final K key; // non-null
3144	>	V val;       // non-null
3145	>	final ConcurrentHashMap<K, V> map;
3146	>	MapEntry(K key, V val, ConcurrentHashMap<K, V> map) {
3147	>	this.key = key;
3148	>	this.val = val;
3149	>	this.map = map;
3150	>	}
3151	>	public final K getKey()       { return key; }
3152	>	public final V getValue()     { return val; }
3153	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3154	>	public final String toString(){ return key + "=" + val; }
3155	>
3156	>	public final boolean equals(Object o) {
3157	>	Object k, v; Map.Entry<?,?> e;
3158	>	return ((o instanceof Map.Entry) &&
3159	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3160	>	(v = e.getValue()) != null &&
3161	>	(k == key || k.equals(key)) &&
3162	>	(v == val || v.equals(val)));
3163		}
3164
3165		/**
3166		* Sets our entry's value and writes through to the map. The
3167	<	* value to return is somewhat arbitrary here. Since a
3168	<	* WriteThroughEntry does not necessarily track asynchronous
3169	<	* changes, the most recent "previous" value could be
3170	<	* different from what we return (or could even have been
3171	<	* removed in which case the put will re-establish). We do not
1310	<	* and cannot guarantee more.
3167	>	* value to return is somewhat arbitrary here. Since we do not
3168	>	* necessarily track asynchronous changes, the most recent
3169	>	* "previous" value could be different from what we return (or
3170	>	* could even have been removed in which case the put will
3171	>	* re-establish). We do not and cannot guarantee more.
3172		*/
3173	<	public V setValue(V value) {
3173	>	public final V setValue(V value) {
3174		if (value == null) throw new NullPointerException();
3175	<	V v = super.setValue(value);
3176	<	ConcurrentHashMap.this.put(getKey(), value);
3175	>	V v = val;
3176	>	val = value;
3177	>	map.put(key, value);
3178		return v;
3179		}
3180		}
3181
3182	<	final class EntryIterator
3183	<	extends HashIterator
3184	<	implements Iterator<Entry<K,V>>
3185	<	{
3186	<	public Map.Entry<K,V> next() {
3187	<	HashEntry<K,V> e = super.nextEntry();
1326	<	return new WriteThroughEntry(e.key, e.value);
1327	<	}
3182	>	/**
3183	>	* Returns exportable snapshot entry for the given key and value
3184	>	* when write-through can't or shouldn't be used.
3185	>	*/
3186	>	static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
3187	>	return new AbstractMap.SimpleEntry<K,V>(k, v);
3188		}
3189
3190	<	final class KeySet extends AbstractSet<K> {
3191	<	public Iterator<K> iterator() {
3192	<	return new KeyIterator();
3190	>	/* ---------------- Serialization Support -------------- */
3191	>
3192	>	/**
3193	>	* Stripped-down version of helper class used in previous version,
3194	>	* declared for the sake of serialization compatibility
3195	>	*/
3196	>	static class Segment<K,V> implements Serializable {
3197	>	private static final long serialVersionUID = 2249069246763182397L;
3198	>	final float loadFactor;
3199	>	Segment(float lf) { this.loadFactor = lf; }
3200	>	}
3201	>
3202	>	/**
3203	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
3204	>	* stream (i.e., serializes it).
3205	>	* @param s the stream
3206	>	* @serialData
3207	>	* the key (Object) and value (Object)
3208	>	* for each key-value mapping, followed by a null pair.
3209	>	* The key-value mappings are emitted in no particular order.
3210	>	*/
3211	>	@SuppressWarnings("unchecked") private void writeObject
3212	>	(java.io.ObjectOutputStream s)
3213	>	throws java.io.IOException {
3214	>	if (segments == null) { // for serialization compatibility
3215	>	segments = (Segment<K,V>[])
3216	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3217	>	for (int i = 0; i < segments.length; ++i)
3218	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3219		}
3220	<	public int size() {
3221	<	return ConcurrentHashMap.this.size();
3220	>	s.defaultWriteObject();
3221	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3222	>	V v;
3223	>	while ((v = it.advance()) != null) {
3224	>	s.writeObject(it.nextKey);
3225	>	s.writeObject(v);
3226		}
3227	<	public boolean isEmpty() {
3228	<	return ConcurrentHashMap.this.isEmpty();
3227	>	s.writeObject(null);
3228	>	s.writeObject(null);
3229	>	segments = null; // throw away
3230	>	}
3231	>
3232	>	/**
3233	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3234	>	* @param s the stream
3235	>	*/
3236	>	@SuppressWarnings("unchecked") private void readObject
3237	>	(java.io.ObjectInputStream s)
3238	>	throws java.io.IOException, ClassNotFoundException {
3239	>	s.defaultReadObject();
3240	>	this.segments = null; // unneeded
3241	>
3242	>	// Create all nodes, then place in table once size is known
3243	>	long size = 0L;
3244	>	Node<V> p = null;
3245	>	for (;;) {
3246	>	K k = (K) s.readObject();
3247	>	V v = (V) s.readObject();
3248	>	if (k != null && v != null) {
3249	>	int h = spread(k.hashCode());
3250	>	p = new Node<V>(h, k, v, p);
3251	>	++size;
3252	>	}
3253	>	else
3254	>	break;
3255		}
3256	<	public boolean contains(Object o) {
3257	<	return ConcurrentHashMap.this.containsKey(o);
3256	>	if (p != null) {
3257	>	boolean init = false;
3258	>	int n;
3259	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3260	>	n = MAXIMUM_CAPACITY;
3261	>	else {
3262	>	int sz = (int)size;
3263	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3264	>	}
3265	>	int sc = sizeCtl;
3266	>	boolean collide = false;
3267	>	if (n > sc &&
3268	>	U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
3269	>	try {
3270	>	if (table == null) {
3271	>	init = true;
3272	>	@SuppressWarnings("rawtypes") Node[] rt = new Node[n];
3273	>	Node<V>[] tab = (Node<V>[])rt;
3274	>	int mask = n - 1;
3275	>	while (p != null) {
3276	>	int j = p.hash & mask;
3277	>	Node<V> next = p.next;
3278	>	Node<V> q = p.next = tabAt(tab, j);
3279	>	setTabAt(tab, j, p);
3280	>	if (!collide && q != null && q.hash == p.hash)
3281	>	collide = true;
3282	>	p = next;
3283	>	}
3284	>	table = tab;
3285	>	addCount(size, -1);
3286	>	sc = n - (n >>> 2);
3287	>	}
3288	>	} finally {
3289	>	sizeCtl = sc;
3290	>	}
3291	>	if (collide) { // rescan and convert to TreeBins
3292	>	Node<V>[] tab = table;
3293	>	for (int i = 0; i < tab.length; ++i) {
3294	>	int c = 0;
3295	>	for (Node<V> e = tabAt(tab, i); e != null; e = e.next) {
3296	>	if (++c > TREE_THRESHOLD &&
3297	>	(e.key instanceof Comparable)) {
3298	>	replaceWithTreeBin(tab, i, e.key);
3299	>	break;
3300	>	}
3301	>	}
3302	>	}
3303	>	}
3304	>	}
3305	>	if (!init) { // Can only happen if unsafely published.
3306	>	while (p != null) {
3307	>	internalPut((K)p.key, p.val, false);
3308	>	p = p.next;
3309	>	}
3310	>	}
3311		}
3312	<	public boolean remove(Object o) {
3313	<	return ConcurrentHashMap.this.remove(o) != null;
3312	>	}
3313	>
3314	>	// -------------------------------------------------------
3315	>
3316	>	// Sams
3317	>	/** Interface describing a void action of one argument */
3318	>	public interface Action<A> { void apply(A a); }
3319	>	/** Interface describing a void action of two arguments */
3320	>	public interface BiAction<A,B> { void apply(A a, B b); }
3321	>	/** Interface describing a function of one argument */
3322	>	public interface Fun<A,T> { T apply(A a); }
3323	>	/** Interface describing a function of two arguments */
3324	>	public interface BiFun<A,B,T> { T apply(A a, B b); }
3325	>	/** Interface describing a function of no arguments */
3326	>	public interface Generator<T> { T apply(); }
3327	>	/** Interface describing a function mapping its argument to a double */
3328	>	public interface ObjectToDouble<A> { double apply(A a); }
3329	>	/** Interface describing a function mapping its argument to a long */
3330	>	public interface ObjectToLong<A> { long apply(A a); }
3331	>	/** Interface describing a function mapping its argument to an int */
3332	>	public interface ObjectToInt<A> {int apply(A a); }
3333	>	/** Interface describing a function mapping two arguments to a double */
3334	>	public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
3335	>	/** Interface describing a function mapping two arguments to a long */
3336	>	public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
3337	>	/** Interface describing a function mapping two arguments to an int */
3338	>	public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }
3339	>	/** Interface describing a function mapping a double to a double */
3340	>	public interface DoubleToDouble { double apply(double a); }
3341	>	/** Interface describing a function mapping a long to a long */
3342	>	public interface LongToLong { long apply(long a); }
3343	>	/** Interface describing a function mapping an int to an int */
3344	>	public interface IntToInt { int apply(int a); }
3345	>	/** Interface describing a function mapping two doubles to a double */
3346	>	public interface DoubleByDoubleToDouble { double apply(double a, double b); }
3347	>	/** Interface describing a function mapping two longs to a long */
3348	>	public interface LongByLongToLong { long apply(long a, long b); }
3349	>	/** Interface describing a function mapping two ints to an int */
3350	>	public interface IntByIntToInt { int apply(int a, int b); }
3351	>
3352	>
3353	>	// -------------------------------------------------------
3354	>
3355	>	// Sequential bulk operations
3356	>
3357	>	/**
3358	>	* Performs the given action for each (key, value).
3359	>	*
3360	>	* @param action the action
3361	>	*/
3362	>	@SuppressWarnings("unchecked") public void forEachSequentially
3363	>	(BiAction<K,V> action) {
3364	>	if (action == null) throw new NullPointerException();
3365	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3366	>	V v;
3367	>	while ((v = it.advance()) != null)
3368	>	action.apply((K)it.nextKey, v);
3369	>	}
3370	>
3371	>	/**
3372	>	* Performs the given action for each non-null transformation
3373	>	* of each (key, value).
3374	>	*
3375	>	* @param transformer a function returning the transformation
3376	>	* for an element, or null of there is no transformation (in
3377	>	* which case the action is not applied).
3378	>	* @param action the action
3379	>	*/
3380	>	@SuppressWarnings("unchecked") public <U> void forEachSequentially
3381	>	(BiFun<? super K, ? super V, ? extends U> transformer,
3382	>	Action<U> action) {
3383	>	if (transformer == null || action == null)
3384	>	throw new NullPointerException();
3385	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3386	>	V v; U u;
3387	>	while ((v = it.advance()) != null) {
3388	>	if ((u = transformer.apply((K)it.nextKey, v)) != null)
3389	>	action.apply(u);
3390		}
3391	<	public void clear() {
3392	<	ConcurrentHashMap.this.clear();
3391	>	}
3392	>
3393	>	/**
3394	>	* Returns a non-null result from applying the given search
3395	>	* function on each (key, value), or null if none.
3396	>	*
3397	>	* @param searchFunction a function returning a non-null
3398	>	* result on success, else null
3399	>	* @return a non-null result from applying the given search
3400	>	* function on each (key, value), or null if none
3401	>	*/
3402	>	@SuppressWarnings("unchecked") public <U> U searchSequentially
3403	>	(BiFun<? super K, ? super V, ? extends U> searchFunction) {
3404	>	if (searchFunction == null) throw new NullPointerException();
3405	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3406	>	V v; U u;
3407	>	while ((v = it.advance()) != null) {
3408	>	if ((u = searchFunction.apply((K)it.nextKey, v)) != null)
3409	>	return u;
3410		}
3411	+	return null;
3412		}
3413
3414	<	final class Values extends AbstractCollection<V> {
3415	<	public Iterator<V> iterator() {
3416	<	return new ValueIterator();
3414	>	/**
3415	>	* Returns the result of accumulating the given transformation
3416	>	* of all (key, value) pairs using the given reducer to
3417	>	* combine values, or null if none.
3418	>	*
3419	>	* @param transformer a function returning the transformation
3420	>	* for an element, or null of there is no transformation (in
3421	>	* which case it is not combined).
3422	>	* @param reducer a commutative associative combining function
3423	>	* @return the result of accumulating the given transformation
3424	>	* of all (key, value) pairs
3425	>	*/
3426	>	@SuppressWarnings("unchecked") public <U> U reduceSequentially
3427	>	(BiFun<? super K, ? super V, ? extends U> transformer,
3428	>	BiFun<? super U, ? super U, ? extends U> reducer) {
3429	>	if (transformer == null || reducer == null)
3430	>	throw new NullPointerException();
3431	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3432	>	U r = null, u; V v;
3433	>	while ((v = it.advance()) != null) {
3434	>	if ((u = transformer.apply((K)it.nextKey, v)) != null)
3435	>	r = (r == null) ? u : reducer.apply(r, u);
3436		}
3437	<	public int size() {
3438	<	return ConcurrentHashMap.this.size();
3437	>	return r;
3438	>	}
3439	>
3440	>	/**
3441	>	* Returns the result of accumulating the given transformation
3442	>	* of all (key, value) pairs using the given reducer to
3443	>	* combine values, and the given basis as an identity value.
3444	>	*
3445	>	* @param transformer a function returning the transformation
3446	>	* for an element
3447	>	* @param basis the identity (initial default value) for the reduction
3448	>	* @param reducer a commutative associative combining function
3449	>	* @return the result of accumulating the given transformation
3450	>	* of all (key, value) pairs
3451	>	*/
3452	>	@SuppressWarnings("unchecked") public double reduceToDoubleSequentially
3453	>	(ObjectByObjectToDouble<? super K, ? super V> transformer,
3454	>	double basis,
3455	>	DoubleByDoubleToDouble reducer) {
3456	>	if (transformer == null || reducer == null)
3457	>	throw new NullPointerException();
3458	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3459	>	double r = basis; V v;
3460	>	while ((v = it.advance()) != null)
3461	>	r = reducer.apply(r, transformer.apply((K)it.nextKey, v));
3462	>	return r;
3463	>	}
3464	>
3465	>	/**
3466	>	* Returns the result of accumulating the given transformation
3467	>	* of all (key, value) pairs using the given reducer to
3468	>	* combine values, and the given basis as an identity value.
3469	>	*
3470	>	* @param transformer a function returning the transformation
3471	>	* for an element
3472	>	* @param basis the identity (initial default value) for the reduction
3473	>	* @param reducer a commutative associative combining function
3474	>	* @return the result of accumulating the given transformation
3475	>	* of all (key, value) pairs
3476	>	*/
3477	>	@SuppressWarnings("unchecked") public long reduceToLongSequentially
3478	>	(ObjectByObjectToLong<? super K, ? super V> transformer,
3479	>	long basis,
3480	>	LongByLongToLong reducer) {
3481	>	if (transformer == null || reducer == null)
3482	>	throw new NullPointerException();
3483	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3484	>	long r = basis; V v;
3485	>	while ((v = it.advance()) != null)
3486	>	r = reducer.apply(r, transformer.apply((K)it.nextKey, v));
3487	>	return r;
3488	>	}
3489	>
3490	>	/**
3491	>	* Returns the result of accumulating the given transformation
3492	>	* of all (key, value) pairs using the given reducer to
3493	>	* combine values, and the given basis as an identity value.
3494	>	*
3495	>	* @param transformer a function returning the transformation
3496	>	* for an element
3497	>	* @param basis the identity (initial default value) for the reduction
3498	>	* @param reducer a commutative associative combining function
3499	>	* @return the result of accumulating the given transformation
3500	>	* of all (key, value) pairs
3501	>	*/
3502	>	@SuppressWarnings("unchecked") public int reduceToIntSequentially
3503	>	(ObjectByObjectToInt<? super K, ? super V> transformer,
3504	>	int basis,
3505	>	IntByIntToInt reducer) {
3506	>	if (transformer == null || reducer == null)
3507	>	throw new NullPointerException();
3508	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3509	>	int r = basis; V v;
3510	>	while ((v = it.advance()) != null)
3511	>	r = reducer.apply(r, transformer.apply((K)it.nextKey, v));
3512	>	return r;
3513	>	}
3514	>
3515	>	/**
3516	>	* Performs the given action for each key.
3517	>	*
3518	>	* @param action the action
3519	>	*/
3520	>	@SuppressWarnings("unchecked") public void forEachKeySequentially
3521	>	(Action<K> action) {
3522	>	if (action == null) throw new NullPointerException();
3523	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3524	>	while (it.advance() != null)
3525	>	action.apply((K)it.nextKey);
3526	>	}
3527	>
3528	>	/**
3529	>	* Performs the given action for each non-null transformation
3530	>	* of each key.
3531	>	*
3532	>	* @param transformer a function returning the transformation
3533	>	* for an element, or null of there is no transformation (in
3534	>	* which case the action is not applied).
3535	>	* @param action the action
3536	>	*/
3537	>	@SuppressWarnings("unchecked") public <U> void forEachKeySequentially
3538	>	(Fun<? super K, ? extends U> transformer,
3539	>	Action<U> action) {
3540	>	if (transformer == null || action == null)
3541	>	throw new NullPointerException();
3542	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3543	>	U u;
3544	>	while (it.advance() != null) {
3545	>	if ((u = transformer.apply((K)it.nextKey)) != null)
3546	>	action.apply(u);
3547		}
3548	<	public boolean isEmpty() {
3549	<	return ConcurrentHashMap.this.isEmpty();
3548	>	ForkJoinTasks.forEachKey
3549	>	(this, transformer, action).invoke();
3550	>	}
3551	>
3552	>	/**
3553	>	* Returns a non-null result from applying the given search
3554	>	* function on each key, or null if none.
3555	>	*
3556	>	* @param searchFunction a function returning a non-null
3557	>	* result on success, else null
3558	>	* @return a non-null result from applying the given search
3559	>	* function on each key, or null if none
3560	>	*/
3561	>	@SuppressWarnings("unchecked") public <U> U searchKeysSequentially
3562	>	(Fun<? super K, ? extends U> searchFunction) {
3563	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3564	>	U u;
3565	>	while (it.advance() != null) {
3566	>	if ((u = searchFunction.apply((K)it.nextKey)) != null)
3567	>	return u;
3568		}
3569	<	public boolean contains(Object o) {
3570	<	return ConcurrentHashMap.this.containsValue(o);
3569	>	return null;
3570	>	}
3571	>
3572	>	/**
3573	>	* Returns the result of accumulating all keys using the given
3574	>	* reducer to combine values, or null if none.
3575	>	*
3576	>	* @param reducer a commutative associative combining function
3577	>	* @return the result of accumulating all keys using the given
3578	>	* reducer to combine values, or null if none
3579	>	*/
3580	>	@SuppressWarnings("unchecked") public K reduceKeysSequentially
3581	>	(BiFun<? super K, ? super K, ? extends K> reducer) {
3582	>	if (reducer == null) throw new NullPointerException();
3583	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3584	>	K r = null;
3585	>	while (it.advance() != null) {
3586	>	K u = (K)it.nextKey;
3587	>	r = (r == null) ? u : reducer.apply(r, u);
3588	>	}
3589	>	return r;
3590	>	}
3591	>
3592	>	/**
3593	>	* Returns the result of accumulating the given transformation
3594	>	* of all keys using the given reducer to combine values, or
3595	>	* null if none.
3596	>	*
3597	>	* @param transformer a function returning the transformation
3598	>	* for an element, or null of there is no transformation (in
3599	>	* which case it is not combined).
3600	>	* @param reducer a commutative associative combining function
3601	>	* @return the result of accumulating the given transformation
3602	>	* of all keys
3603	>	*/
3604	>	@SuppressWarnings("unchecked") public <U> U reduceKeysSequentially
3605	>	(Fun<? super K, ? extends U> transformer,
3606	>	BiFun<? super U, ? super U, ? extends U> reducer) {
3607	>	if (transformer == null || reducer == null)
3608	>	throw new NullPointerException();
3609	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3610	>	U r = null, u;
3611	>	while (it.advance() != null) {
3612	>	if ((u = transformer.apply((K)it.nextKey)) != null)
3613	>	r = (r == null) ? u : reducer.apply(r, u);
3614		}
3615	<	public void clear() {
3616	<	ConcurrentHashMap.this.clear();
3615	>	return r;
3616	>	}
3617	>
3618	>	/**
3619	>	* Returns the result of accumulating the given transformation
3620	>	* of all keys using the given reducer to combine values, and
3621	>	* the given basis as an identity value.
3622	>	*
3623	>	* @param transformer a function returning the transformation
3624	>	* for an element
3625	>	* @param basis the identity (initial default value) for the reduction
3626	>	* @param reducer a commutative associative combining function
3627	>	* @return  the result of accumulating the given transformation
3628	>	* of all keys
3629	>	*/
3630	>	@SuppressWarnings("unchecked") public double reduceKeysToDoubleSequentially
3631	>	(ObjectToDouble<? super K> transformer,
3632	>	double basis,
3633	>	DoubleByDoubleToDouble reducer) {
3634	>	if (transformer == null || reducer == null)
3635	>	throw new NullPointerException();
3636	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3637	>	double r = basis;
3638	>	while (it.advance() != null)
3639	>	r = reducer.apply(r, transformer.apply((K)it.nextKey));
3640	>	return r;
3641	>	}
3642	>
3643	>	/**
3644	>	* Returns the result of accumulating the given transformation
3645	>	* of all keys using the given reducer to combine values, and
3646	>	* the given basis as an identity value.
3647	>	*
3648	>	* @param transformer a function returning the transformation
3649	>	* for an element
3650	>	* @param basis the identity (initial default value) for the reduction
3651	>	* @param reducer a commutative associative combining function
3652	>	* @return the result of accumulating the given transformation
3653	>	* of all keys
3654	>	*/
3655	>	@SuppressWarnings("unchecked") public long reduceKeysToLongSequentially
3656	>	(ObjectToLong<? super K> transformer,
3657	>	long basis,
3658	>	LongByLongToLong reducer) {
3659	>	if (transformer == null || reducer == null)
3660	>	throw new NullPointerException();
3661	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3662	>	long r = basis;
3663	>	while (it.advance() != null)
3664	>	r = reducer.apply(r, transformer.apply((K)it.nextKey));
3665	>	return r;
3666	>	}
3667	>
3668	>	/**
3669	>	* Returns the result of accumulating the given transformation
3670	>	* of all keys using the given reducer to combine values, and
3671	>	* the given basis as an identity value.
3672	>	*
3673	>	* @param transformer a function returning the transformation
3674	>	* for an element
3675	>	* @param basis the identity (initial default value) for the reduction
3676	>	* @param reducer a commutative associative combining function
3677	>	* @return the result of accumulating the given transformation
3678	>	* of all keys
3679	>	*/
3680	>	@SuppressWarnings("unchecked") public int reduceKeysToIntSequentially
3681	>	(ObjectToInt<? super K> transformer,
3682	>	int basis,
3683	>	IntByIntToInt reducer) {
3684	>	if (transformer == null || reducer == null)
3685	>	throw new NullPointerException();
3686	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3687	>	int r = basis;
3688	>	while (it.advance() != null)
3689	>	r = reducer.apply(r, transformer.apply((K)it.nextKey));
3690	>	return r;
3691	>	}
3692	>
3693	>	/**
3694	>	* Performs the given action for each value.
3695	>	*
3696	>	* @param action the action
3697	>	*/
3698	>	public void forEachValueSequentially(Action<V> action) {
3699	>	if (action == null) throw new NullPointerException();
3700	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3701	>	V v;
3702	>	while ((v = it.advance()) != null)
3703	>	action.apply(v);
3704	>	}
3705	>
3706	>	/**
3707	>	* Performs the given action for each non-null transformation
3708	>	* of each value.
3709	>	*
3710	>	* @param transformer a function returning the transformation
3711	>	* for an element, or null of there is no transformation (in
3712	>	* which case the action is not applied).
3713	>	*/
3714	>	public <U> void forEachValueSequentially
3715	>	(Fun<? super V, ? extends U> transformer,
3716	>	Action<U> action) {
3717	>	if (transformer == null || action == null)
3718	>	throw new NullPointerException();
3719	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3720	>	V v; U u;
3721	>	while ((v = it.advance()) != null) {
3722	>	if ((u = transformer.apply(v)) != null)
3723	>	action.apply(u);
3724		}
3725		}
3726
3727	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3728	<	public Iterator<Map.Entry<K,V>> iterator() {
3729	<	return new EntryIterator();
3727	>	/**
3728	>	* Returns a non-null result from applying the given search
3729	>	* function on each value, or null if none.
3730	>	*
3731	>	* @param searchFunction a function returning a non-null
3732	>	* result on success, else null
3733	>	* @return a non-null result from applying the given search
3734	>	* function on each value, or null if none
3735	>	*
3736	>	*/
3737	>	public <U> U searchValuesSequentially
3738	>	(Fun<? super V, ? extends U> searchFunction) {
3739	>	if (searchFunction == null) throw new NullPointerException();
3740	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3741	>	V v; U u;
3742	>	while ((v = it.advance()) != null) {
3743	>	if ((u = searchFunction.apply(v)) != null)
3744	>	return u;
3745		}
3746	<	public boolean contains(Object o) {
3747	<	if (!(o instanceof Map.Entry))
3748	<	return false;
3749	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3750	<	V v = ConcurrentHashMap.this.get(e.getKey());
3751	<	return v != null && v.equals(e.getValue());
3746	>	return null;
3747	>	}
3748	>
3749	>	/**
3750	>	* Returns the result of accumulating all values using the
3751	>	* given reducer to combine values, or null if none.
3752	>	*
3753	>	* @param reducer a commutative associative combining function
3754	>	* @return  the result of accumulating all values
3755	>	*/
3756	>	public V reduceValuesSequentially
3757	>	(BiFun<? super V, ? super V, ? extends V> reducer) {
3758	>	if (reducer == null) throw new NullPointerException();
3759	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3760	>	V r = null; V v;
3761	>	while ((v = it.advance()) != null)
3762	>	r = (r == null) ? v : reducer.apply(r, v);
3763	>	return r;
3764	>	}
3765	>
3766	>	/**
3767	>	* Returns the result of accumulating the given transformation
3768	>	* of all values using the given reducer to combine values, or
3769	>	* null if none.
3770	>	*
3771	>	* @param transformer a function returning the transformation
3772	>	* for an element, or null of there is no transformation (in
3773	>	* which case it is not combined).
3774	>	* @param reducer a commutative associative combining function
3775	>	* @return the result of accumulating the given transformation
3776	>	* of all values
3777	>	*/
3778	>	public <U> U reduceValuesSequentially
3779	>	(Fun<? super V, ? extends U> transformer,
3780	>	BiFun<? super U, ? super U, ? extends U> reducer) {
3781	>	if (transformer == null || reducer == null)
3782	>	throw new NullPointerException();
3783	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3784	>	U r = null, u; V v;
3785	>	while ((v = it.advance()) != null) {
3786	>	if ((u = transformer.apply(v)) != null)
3787	>	r = (r == null) ? u : reducer.apply(r, u);
3788		}
3789	<	public boolean remove(Object o) {
3790	<	if (!(o instanceof Map.Entry))
3791	<	return false;
3792	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3793	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
3789	>	return r;
3790	>	}
3791	>
3792	>	/**
3793	>	* Returns the result of accumulating the given transformation
3794	>	* of all values using the given reducer to combine values,
3795	>	* and the given basis as an identity value.
3796	>	*
3797	>	* @param transformer a function returning the transformation
3798	>	* for an element
3799	>	* @param basis the identity (initial default value) for the reduction
3800	>	* @param reducer a commutative associative combining function
3801	>	* @return the result of accumulating the given transformation
3802	>	* of all values
3803	>	*/
3804	>	public double reduceValuesToDoubleSequentially
3805	>	(ObjectToDouble<? super V> transformer,
3806	>	double basis,
3807	>	DoubleByDoubleToDouble reducer) {
3808	>	if (transformer == null || reducer == null)
3809	>	throw new NullPointerException();
3810	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3811	>	double r = basis; V v;
3812	>	while ((v = it.advance()) != null)
3813	>	r = reducer.apply(r, transformer.apply(v));
3814	>	return r;
3815	>	}
3816	>
3817	>	/**
3818	>	* Returns the result of accumulating the given transformation
3819	>	* of all values using the given reducer to combine values,
3820	>	* and the given basis as an identity value.
3821	>	*
3822	>	* @param transformer a function returning the transformation
3823	>	* for an element
3824	>	* @param basis the identity (initial default value) for the reduction
3825	>	* @param reducer a commutative associative combining function
3826	>	* @return the result of accumulating the given transformation
3827	>	* of all values
3828	>	*/
3829	>	public long reduceValuesToLongSequentially
3830	>	(ObjectToLong<? super V> transformer,
3831	>	long basis,
3832	>	LongByLongToLong reducer) {
3833	>	if (transformer == null || reducer == null)
3834	>	throw new NullPointerException();
3835	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3836	>	long r = basis; V v;
3837	>	while ((v = it.advance()) != null)
3838	>	r = reducer.apply(r, transformer.apply(v));
3839	>	return r;
3840	>	}
3841	>
3842	>	/**
3843	>	* Returns the result of accumulating the given transformation
3844	>	* of all values using the given reducer to combine values,
3845	>	* and the given basis as an identity value.
3846	>	*
3847	>	* @param transformer a function returning the transformation
3848	>	* for an element
3849	>	* @param basis the identity (initial default value) for the reduction
3850	>	* @param reducer a commutative associative combining function
3851	>	* @return the result of accumulating the given transformation
3852	>	* of all values
3853	>	*/
3854	>	public int reduceValuesToIntSequentially
3855	>	(ObjectToInt<? super V> transformer,
3856	>	int basis,
3857	>	IntByIntToInt reducer) {
3858	>	if (transformer == null || reducer == null)
3859	>	throw new NullPointerException();
3860	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3861	>	int r = basis; V v;
3862	>	while ((v = it.advance()) != null)
3863	>	r = reducer.apply(r, transformer.apply(v));
3864	>	return r;
3865	>	}
3866	>
3867	>	/**
3868	>	* Performs the given action for each entry.
3869	>	*
3870	>	* @param action the action
3871	>	*/
3872	>	@SuppressWarnings("unchecked") public void forEachEntrySequentially
3873	>	(Action<Map.Entry<K,V>> action) {
3874	>	if (action == null) throw new NullPointerException();
3875	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3876	>	V v;
3877	>	while ((v = it.advance()) != null)
3878	>	action.apply(entryFor((K)it.nextKey, v));
3879	>	}
3880	>
3881	>	/**
3882	>	* Performs the given action for each non-null transformation
3883	>	* of each entry.
3884	>	*
3885	>	* @param transformer a function returning the transformation
3886	>	* for an element, or null of there is no transformation (in
3887	>	* which case the action is not applied).
3888	>	* @param action the action
3889	>	*/
3890	>	@SuppressWarnings("unchecked") public <U> void forEachEntrySequentially
3891	>	(Fun<Map.Entry<K,V>, ? extends U> transformer,
3892	>	Action<U> action) {
3893	>	if (transformer == null || action == null)
3894	>	throw new NullPointerException();
3895	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3896	>	V v; U u;
3897	>	while ((v = it.advance()) != null) {
3898	>	if ((u = transformer.apply(entryFor((K)it.nextKey, v))) != null)
3899	>	action.apply(u);
3900		}
3901	<	public int size() {
3902	<	return ConcurrentHashMap.this.size();
3901	>	}
3902	>
3903	>	/**
3904	>	* Returns a non-null result from applying the given search
3905	>	* function on each entry, or null if none.
3906	>	*
3907	>	* @param searchFunction a function returning a non-null
3908	>	* result on success, else null
3909	>	* @return a non-null result from applying the given search
3910	>	* function on each entry, or null if none
3911	>	*/
3912	>	@SuppressWarnings("unchecked") public <U> U searchEntriesSequentially
3913	>	(Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
3914	>	if (searchFunction == null) throw new NullPointerException();
3915	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3916	>	V v; U u;
3917	>	while ((v = it.advance()) != null) {
3918	>	if ((u = searchFunction.apply(entryFor((K)it.nextKey, v))) != null)
3919	>	return u;
3920		}
3921	<	public boolean isEmpty() {
3922	<	return ConcurrentHashMap.this.isEmpty();
3921	>	return null;
3922	>	}
3923	>
3924	>	/**
3925	>	* Returns the result of accumulating all entries using the
3926	>	* given reducer to combine values, or null if none.
3927	>	*
3928	>	* @param reducer a commutative associative combining function
3929	>	* @return the result of accumulating all entries
3930	>	*/
3931	>	@SuppressWarnings("unchecked") public Map.Entry<K,V> reduceEntriesSequentially
3932	>	(BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3933	>	if (reducer == null) throw new NullPointerException();
3934	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3935	>	Map.Entry<K,V> r = null; V v;
3936	>	while ((v = it.advance()) != null) {
3937	>	Map.Entry<K,V> u = entryFor((K)it.nextKey, v);
3938	>	r = (r == null) ? u : reducer.apply(r, u);
3939		}
3940	<	public void clear() {
3941	<	ConcurrentHashMap.this.clear();
3940	>	return r;
3941	>	}
3942	>
3943	>	/**
3944	>	* Returns the result of accumulating the given transformation
3945	>	* of all entries using the given reducer to combine values,
3946	>	* or null if none.
3947	>	*
3948	>	* @param transformer a function returning the transformation
3949	>	* for an element, or null of there is no transformation (in
3950	>	* which case it is not combined).
3951	>	* @param reducer a commutative associative combining function
3952	>	* @return the result of accumulating the given transformation
3953	>	* of all entries
3954	>	*/
3955	>	@SuppressWarnings("unchecked") public <U> U reduceEntriesSequentially
3956	>	(Fun<Map.Entry<K,V>, ? extends U> transformer,
3957	>	BiFun<? super U, ? super U, ? extends U> reducer) {
3958	>	if (transformer == null || reducer == null)
3959	>	throw new NullPointerException();
3960	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3961	>	U r = null, u; V v;
3962	>	while ((v = it.advance()) != null) {
3963	>	if ((u = transformer.apply(entryFor((K)it.nextKey, v))) != null)
3964	>	r = (r == null) ? u : reducer.apply(r, u);
3965		}
3966	+	return r;
3967		}
3968
3969	<	/* ---------------- Serialization Support -------------- */
3969	>	/**
3970	>	* Returns the result of accumulating the given transformation
3971	>	* of all entries using the given reducer to combine values,
3972	>	* and the given basis as an identity value.
3973	>	*
3974	>	* @param transformer a function returning the transformation
3975	>	* for an element
3976	>	* @param basis the identity (initial default value) for the reduction
3977	>	* @param reducer a commutative associative combining function
3978	>	* @return the result of accumulating the given transformation
3979	>	* of all entries
3980	>	*/
3981	>	@SuppressWarnings("unchecked") public double reduceEntriesToDoubleSequentially
3982	>	(ObjectToDouble<Map.Entry<K,V>> transformer,
3983	>	double basis,
3984	>	DoubleByDoubleToDouble reducer) {
3985	>	if (transformer == null || reducer == null)
3986	>	throw new NullPointerException();
3987	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3988	>	double r = basis; V v;
3989	>	while ((v = it.advance()) != null)
3990	>	r = reducer.apply(r, transformer.apply(entryFor((K)it.nextKey, v)));
3991	>	return r;
3992	>	}
3993
3994		/**
3995	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
3996	<	* stream (i.e., serializes it).
3997	<	* @param s the stream
3998	<	* @serialData
3999	<	* the key (Object) and value (Object)
4000	<	* for each key-value mapping, followed by a null pair.
4001	<	* The key-value mappings are emitted in no particular order.
3995	>	* Returns the result of accumulating the given transformation
3996	>	* of all entries using the given reducer to combine values,
3997	>	* and the given basis as an identity value.
3998	>	*
3999	>	* @param transformer a function returning the transformation
4000	>	* for an element
4001	>	* @param basis the identity (initial default value) for the reduction
4002	>	* @param reducer a commutative associative combining function
4003	>	* @return  the result of accumulating the given transformation
4004	>	* of all entries
4005	>	*/
4006	>	@SuppressWarnings("unchecked") public long reduceEntriesToLongSequentially
4007	>	(ObjectToLong<Map.Entry<K,V>> transformer,
4008	>	long basis,
4009	>	LongByLongToLong reducer) {
4010	>	if (transformer == null || reducer == null)
4011	>	throw new NullPointerException();
4012	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
4013	>	long r = basis; V v;
4014	>	while ((v = it.advance()) != null)
4015	>	r = reducer.apply(r, transformer.apply(entryFor((K)it.nextKey, v)));
4016	>	return r;
4017	>	}
4018	>
4019	>	/**
4020	>	* Returns the result of accumulating the given transformation
4021	>	* of all entries using the given reducer to combine values,
4022	>	* and the given basis as an identity value.
4023	>	*
4024	>	* @param transformer a function returning the transformation
4025	>	* for an element
4026	>	* @param basis the identity (initial default value) for the reduction
4027	>	* @param reducer a commutative associative combining function
4028	>	* @return the result of accumulating the given transformation
4029	>	* of all entries
4030	>	*/
4031	>	@SuppressWarnings("unchecked") public int reduceEntriesToIntSequentially
4032	>	(ObjectToInt<Map.Entry<K,V>> transformer,
4033	>	int basis,
4034	>	IntByIntToInt reducer) {
4035	>	if (transformer == null || reducer == null)
4036	>	throw new NullPointerException();
4037	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
4038	>	int r = basis; V v;
4039	>	while ((v = it.advance()) != null)
4040	>	r = reducer.apply(r, transformer.apply(entryFor((K)it.nextKey, v)));
4041	>	return r;
4042	>	}
4043	>
4044	>	// Parallel bulk operations
4045	>
4046	>	/**
4047	>	* Performs the given action for each (key, value).
4048	>	*
4049	>	* @param action the action
4050		*/
4051	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException {
4052	<	// force all segments for serialization compatibility
4053	<	for (int k = 0; k < segments.length; ++k)
4054	<	ensureSegment(k);
1412	<	s.defaultWriteObject();
4051	>	public void forEachInParallel(BiAction<K,V> action) {
4052	>	ForkJoinTasks.forEach
4053	>	(this, action).invoke();
4054	>	}
4055
4056	<	final Segment<K,V>[] segments = this.segments;
4057	<	for (int k = 0; k < segments.length; ++k) {
4058	<	Segment<K,V> seg = segmentAt(segments, k);
4059	<	seg.lock();
4060	<	try {
4061	<	HashEntry<K,V>[] tab = seg.table;
4062	<	for (int i = 0; i < tab.length; ++i) {
4063	<	HashEntry<K,V> e;
4064	<	for (e = entryAt(tab, i); e != null; e = e.next) {
4065	<	s.writeObject(e.key);
4066	<	s.writeObject(e.value);
4056	>	/**
4057	>	* Performs the given action for each non-null transformation
4058	>	* of each (key, value).
4059	>	*
4060	>	* @param transformer a function returning the transformation
4061	>	* for an element, or null of there is no transformation (in
4062	>	* which case the action is not applied).
4063	>	* @param action the action
4064	>	*/
4065	>	public <U> void forEachInParallel
4066	>	(BiFun<? super K, ? super V, ? extends U> transformer,
4067	>	Action<U> action) {
4068	>	ForkJoinTasks.forEach
4069	>	(this, transformer, action).invoke();
4070	>	}
4071	>
4072	>	/**
4073	>	* Returns a non-null result from applying the given search
4074	>	* function on each (key, value), or null if none.  Upon
4075	>	* success, further element processing is suppressed and the
4076	>	* results of any other parallel invocations of the search
4077	>	* function are ignored.
4078	>	*
4079	>	* @param searchFunction a function returning a non-null
4080	>	* result on success, else null
4081	>	* @return a non-null result from applying the given search
4082	>	* function on each (key, value), or null if none
4083	>	*/
4084	>	public <U> U searchInParallel
4085	>	(BiFun<? super K, ? super V, ? extends U> searchFunction) {
4086	>	return ForkJoinTasks.search
4087	>	(this, searchFunction).invoke();
4088	>	}
4089	>
4090	>	/**
4091	>	* Returns the result of accumulating the given transformation
4092	>	* of all (key, value) pairs using the given reducer to
4093	>	* combine values, or null if none.
4094	>	*
4095	>	* @param transformer a function returning the transformation
4096	>	* for an element, or null of there is no transformation (in
4097	>	* which case it is not combined).
4098	>	* @param reducer a commutative associative combining function
4099	>	* @return the result of accumulating the given transformation
4100	>	* of all (key, value) pairs
4101	>	*/
4102	>	public <U> U reduceInParallel
4103	>	(BiFun<? super K, ? super V, ? extends U> transformer,
4104	>	BiFun<? super U, ? super U, ? extends U> reducer) {
4105	>	return ForkJoinTasks.reduce
4106	>	(this, transformer, reducer).invoke();
4107	>	}
4108	>
4109	>	/**
4110	>	* Returns the result of accumulating the given transformation
4111	>	* of all (key, value) pairs using the given reducer to
4112	>	* combine values, and the given basis as an identity value.
4113	>	*
4114	>	* @param transformer a function returning the transformation
4115	>	* for an element
4116	>	* @param basis the identity (initial default value) for the reduction
4117	>	* @param reducer a commutative associative combining function
4118	>	* @return the result of accumulating the given transformation
4119	>	* of all (key, value) pairs
4120	>	*/
4121	>	public double reduceToDoubleInParallel
4122	>	(ObjectByObjectToDouble<? super K, ? super V> transformer,
4123	>	double basis,
4124	>	DoubleByDoubleToDouble reducer) {
4125	>	return ForkJoinTasks.reduceToDouble
4126	>	(this, transformer, basis, reducer).invoke();
4127	>	}
4128	>
4129	>	/**
4130	>	* Returns the result of accumulating the given transformation
4131	>	* of all (key, value) pairs using the given reducer to
4132	>	* combine values, and the given basis as an identity value.
4133	>	*
4134	>	* @param transformer a function returning the transformation
4135	>	* for an element
4136	>	* @param basis the identity (initial default value) for the reduction
4137	>	* @param reducer a commutative associative combining function
4138	>	* @return the result of accumulating the given transformation
4139	>	* of all (key, value) pairs
4140	>	*/
4141	>	public long reduceToLongInParallel
4142	>	(ObjectByObjectToLong<? super K, ? super V> transformer,
4143	>	long basis,
4144	>	LongByLongToLong reducer) {
4145	>	return ForkJoinTasks.reduceToLong
4146	>	(this, transformer, basis, reducer).invoke();
4147	>	}
4148	>
4149	>	/**
4150	>	* Returns the result of accumulating the given transformation
4151	>	* of all (key, value) pairs using the given reducer to
4152	>	* combine values, and the given basis as an identity value.
4153	>	*
4154	>	* @param transformer a function returning the transformation
4155	>	* for an element
4156	>	* @param basis the identity (initial default value) for the reduction
4157	>	* @param reducer a commutative associative combining function
4158	>	* @return the result of accumulating the given transformation
4159	>	* of all (key, value) pairs
4160	>	*/
4161	>	public int reduceToIntInParallel
4162	>	(ObjectByObjectToInt<? super K, ? super V> transformer,
4163	>	int basis,
4164	>	IntByIntToInt reducer) {
4165	>	return ForkJoinTasks.reduceToInt
4166	>	(this, transformer, basis, reducer).invoke();
4167	>	}
4168	>
4169	>	/**
4170	>	* Performs the given action for each key.
4171	>	*
4172	>	* @param action the action
4173	>	*/
4174	>	public void forEachKeyInParallel(Action<K> action) {
4175	>	ForkJoinTasks.forEachKey
4176	>	(this, action).invoke();
4177	>	}
4178	>
4179	>	/**
4180	>	* Performs the given action for each non-null transformation
4181	>	* of each key.
4182	>	*
4183	>	* @param transformer a function returning the transformation
4184	>	* for an element, or null of there is no transformation (in
4185	>	* which case the action is not applied).
4186	>	* @param action the action
4187	>	*/
4188	>	public <U> void forEachKeyInParallel
4189	>	(Fun<? super K, ? extends U> transformer,
4190	>	Action<U> action) {
4191	>	ForkJoinTasks.forEachKey
4192	>	(this, transformer, action).invoke();
4193	>	}
4194	>
4195	>	/**
4196	>	* Returns a non-null result from applying the given search
4197	>	* function on each key, or null if none. Upon success,
4198	>	* further element processing is suppressed and the results of
4199	>	* any other parallel invocations of the search function are
4200	>	* ignored.
4201	>	*
4202	>	* @param searchFunction a function returning a non-null
4203	>	* result on success, else null
4204	>	* @return a non-null result from applying the given search
4205	>	* function on each key, or null if none
4206	>	*/
4207	>	public <U> U searchKeysInParallel
4208	>	(Fun<? super K, ? extends U> searchFunction) {
4209	>	return ForkJoinTasks.searchKeys
4210	>	(this, searchFunction).invoke();
4211	>	}
4212	>
4213	>	/**
4214	>	* Returns the result of accumulating all keys using the given
4215	>	* reducer to combine values, or null if none.
4216	>	*
4217	>	* @param reducer a commutative associative combining function
4218	>	* @return the result of accumulating all keys using the given
4219	>	* reducer to combine values, or null if none
4220	>	*/
4221	>	public K reduceKeysInParallel
4222	>	(BiFun<? super K, ? super K, ? extends K> reducer) {
4223	>	return ForkJoinTasks.reduceKeys
4224	>	(this, reducer).invoke();
4225	>	}
4226	>
4227	>	/**
4228	>	* Returns the result of accumulating the given transformation
4229	>	* of all keys using the given reducer to combine values, or
4230	>	* null if none.
4231	>	*
4232	>	* @param transformer a function returning the transformation
4233	>	* for an element, or null of there is no transformation (in
4234	>	* which case it is not combined).
4235	>	* @param reducer a commutative associative combining function
4236	>	* @return the result of accumulating the given transformation
4237	>	* of all keys
4238	>	*/
4239	>	public <U> U reduceKeysInParallel
4240	>	(Fun<? super K, ? extends U> transformer,
4241	>	BiFun<? super U, ? super U, ? extends U> reducer) {
4242	>	return ForkJoinTasks.reduceKeys
4243	>	(this, transformer, reducer).invoke();
4244	>	}
4245	>
4246	>	/**
4247	>	* Returns the result of accumulating the given transformation
4248	>	* of all keys using the given reducer to combine values, and
4249	>	* the given basis as an identity value.
4250	>	*
4251	>	* @param transformer a function returning the transformation
4252	>	* for an element
4253	>	* @param basis the identity (initial default value) for the reduction
4254	>	* @param reducer a commutative associative combining function
4255	>	* @return  the result of accumulating the given transformation
4256	>	* of all keys
4257	>	*/
4258	>	public double reduceKeysToDoubleInParallel
4259	>	(ObjectToDouble<? super K> transformer,
4260	>	double basis,
4261	>	DoubleByDoubleToDouble reducer) {
4262	>	return ForkJoinTasks.reduceKeysToDouble
4263	>	(this, transformer, basis, reducer).invoke();
4264	>	}
4265	>
4266	>	/**
4267	>	* Returns the result of accumulating the given transformation
4268	>	* of all keys using the given reducer to combine values, and
4269	>	* the given basis as an identity value.
4270	>	*
4271	>	* @param transformer a function returning the transformation
4272	>	* for an element
4273	>	* @param basis the identity (initial default value) for the reduction
4274	>	* @param reducer a commutative associative combining function
4275	>	* @return the result of accumulating the given transformation
4276	>	* of all keys
4277	>	*/
4278	>	public long reduceKeysToLongInParallel
4279	>	(ObjectToLong<? super K> transformer,
4280	>	long basis,
4281	>	LongByLongToLong reducer) {
4282	>	return ForkJoinTasks.reduceKeysToLong
4283	>	(this, transformer, basis, reducer).invoke();
4284	>	}
4285	>
4286	>	/**
4287	>	* Returns the result of accumulating the given transformation
4288	>	* of all keys using the given reducer to combine values, and
4289	>	* the given basis as an identity value.
4290	>	*
4291	>	* @param transformer a function returning the transformation
4292	>	* for an element
4293	>	* @param basis the identity (initial default value) for the reduction
4294	>	* @param reducer a commutative associative combining function
4295	>	* @return the result of accumulating the given transformation
4296	>	* of all keys
4297	>	*/
4298	>	public int reduceKeysToIntInParallel
4299	>	(ObjectToInt<? super K> transformer,
4300	>	int basis,
4301	>	IntByIntToInt reducer) {
4302	>	return ForkJoinTasks.reduceKeysToInt
4303	>	(this, transformer, basis, reducer).invoke();
4304	>	}
4305	>
4306	>	/**
4307	>	* Performs the given action for each value.
4308	>	*
4309	>	* @param action the action
4310	>	*/
4311	>	public void forEachValueInParallel(Action<V> action) {
4312	>	ForkJoinTasks.forEachValue
4313	>	(this, action).invoke();
4314	>	}
4315	>
4316	>	/**
4317	>	* Performs the given action for each non-null transformation
4318	>	* of each value.
4319	>	*
4320	>	* @param transformer a function returning the transformation
4321	>	* for an element, or null of there is no transformation (in
4322	>	* which case the action is not applied).
4323	>	*/
4324	>	public <U> void forEachValueInParallel
4325	>	(Fun<? super V, ? extends U> transformer,
4326	>	Action<U> action) {
4327	>	ForkJoinTasks.forEachValue
4328	>	(this, transformer, action).invoke();
4329	>	}
4330	>
4331	>	/**
4332	>	* Returns a non-null result from applying the given search
4333	>	* function on each value, or null if none.  Upon success,
4334	>	* further element processing is suppressed and the results of
4335	>	* any other parallel invocations of the search function are
4336	>	* ignored.
4337	>	*
4338	>	* @param searchFunction a function returning a non-null
4339	>	* result on success, else null
4340	>	* @return a non-null result from applying the given search
4341	>	* function on each value, or null if none
4342	>	*
4343	>	*/
4344	>	public <U> U searchValuesInParallel
4345	>	(Fun<? super V, ? extends U> searchFunction) {
4346	>	return ForkJoinTasks.searchValues
4347	>	(this, searchFunction).invoke();
4348	>	}
4349	>
4350	>	/**
4351	>	* Returns the result of accumulating all values using the
4352	>	* given reducer to combine values, or null if none.
4353	>	*
4354	>	* @param reducer a commutative associative combining function
4355	>	* @return  the result of accumulating all values
4356	>	*/
4357	>	public V reduceValuesInParallel
4358	>	(BiFun<? super V, ? super V, ? extends V> reducer) {
4359	>	return ForkJoinTasks.reduceValues
4360	>	(this, reducer).invoke();
4361	>	}
4362	>
4363	>	/**
4364	>	* Returns the result of accumulating the given transformation
4365	>	* of all values using the given reducer to combine values, or
4366	>	* null if none.
4367	>	*
4368	>	* @param transformer a function returning the transformation
4369	>	* for an element, or null of there is no transformation (in
4370	>	* which case it is not combined).
4371	>	* @param reducer a commutative associative combining function
4372	>	* @return the result of accumulating the given transformation
4373	>	* of all values
4374	>	*/
4375	>	public <U> U reduceValuesInParallel
4376	>	(Fun<? super V, ? extends U> transformer,
4377	>	BiFun<? super U, ? super U, ? extends U> reducer) {
4378	>	return ForkJoinTasks.reduceValues
4379	>	(this, transformer, reducer).invoke();
4380	>	}
4381	>
4382	>	/**
4383	>	* Returns the result of accumulating the given transformation
4384	>	* of all values using the given reducer to combine values,
4385	>	* and the given basis as an identity value.
4386	>	*
4387	>	* @param transformer a function returning the transformation
4388	>	* for an element
4389	>	* @param basis the identity (initial default value) for the reduction
4390	>	* @param reducer a commutative associative combining function
4391	>	* @return the result of accumulating the given transformation
4392	>	* of all values
4393	>	*/
4394	>	public double reduceValuesToDoubleInParallel
4395	>	(ObjectToDouble<? super V> transformer,
4396	>	double basis,
4397	>	DoubleByDoubleToDouble reducer) {
4398	>	return ForkJoinTasks.reduceValuesToDouble
4399	>	(this, transformer, basis, reducer).invoke();
4400	>	}
4401	>
4402	>	/**
4403	>	* Returns the result of accumulating the given transformation
4404	>	* of all values using the given reducer to combine values,
4405	>	* and the given basis as an identity value.
4406	>	*
4407	>	* @param transformer a function returning the transformation
4408	>	* for an element
4409	>	* @param basis the identity (initial default value) for the reduction
4410	>	* @param reducer a commutative associative combining function
4411	>	* @return the result of accumulating the given transformation
4412	>	* of all values
4413	>	*/
4414	>	public long reduceValuesToLongInParallel
4415	>	(ObjectToLong<? super V> transformer,
4416	>	long basis,
4417	>	LongByLongToLong reducer) {
4418	>	return ForkJoinTasks.reduceValuesToLong
4419	>	(this, transformer, basis, reducer).invoke();
4420	>	}
4421	>
4422	>	/**
4423	>	* Returns the result of accumulating the given transformation
4424	>	* of all values using the given reducer to combine values,
4425	>	* and the given basis as an identity value.
4426	>	*
4427	>	* @param transformer a function returning the transformation
4428	>	* for an element
4429	>	* @param basis the identity (initial default value) for the reduction
4430	>	* @param reducer a commutative associative combining function
4431	>	* @return the result of accumulating the given transformation
4432	>	* of all values
4433	>	*/
4434	>	public int reduceValuesToIntInParallel
4435	>	(ObjectToInt<? super V> transformer,
4436	>	int basis,
4437	>	IntByIntToInt reducer) {
4438	>	return ForkJoinTasks.reduceValuesToInt
4439	>	(this, transformer, basis, reducer).invoke();
4440	>	}
4441	>
4442	>	/**
4443	>	* Performs the given action for each entry.
4444	>	*
4445	>	* @param action the action
4446	>	*/
4447	>	public void forEachEntryInParallel(Action<Map.Entry<K,V>> action) {
4448	>	ForkJoinTasks.forEachEntry
4449	>	(this, action).invoke();
4450	>	}
4451	>
4452	>	/**
4453	>	* Performs the given action for each non-null transformation
4454	>	* of each entry.
4455	>	*
4456	>	* @param transformer a function returning the transformation
4457	>	* for an element, or null of there is no transformation (in
4458	>	* which case the action is not applied).
4459	>	* @param action the action
4460	>	*/
4461	>	public <U> void forEachEntryInParallel
4462	>	(Fun<Map.Entry<K,V>, ? extends U> transformer,
4463	>	Action<U> action) {
4464	>	ForkJoinTasks.forEachEntry
4465	>	(this, transformer, action).invoke();
4466	>	}
4467	>
4468	>	/**
4469	>	* Returns a non-null result from applying the given search
4470	>	* function on each entry, or null if none.  Upon success,
4471	>	* further element processing is suppressed and the results of
4472	>	* any other parallel invocations of the search function are
4473	>	* ignored.
4474	>	*
4475	>	* @param searchFunction a function returning a non-null
4476	>	* result on success, else null
4477	>	* @return a non-null result from applying the given search
4478	>	* function on each entry, or null if none
4479	>	*/
4480	>	public <U> U searchEntriesInParallel
4481	>	(Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
4482	>	return ForkJoinTasks.searchEntries
4483	>	(this, searchFunction).invoke();
4484	>	}
4485	>
4486	>	/**
4487	>	* Returns the result of accumulating all entries using the
4488	>	* given reducer to combine values, or null if none.
4489	>	*
4490	>	* @param reducer a commutative associative combining function
4491	>	* @return the result of accumulating all entries
4492	>	*/
4493	>	public Map.Entry<K,V> reduceEntriesInParallel
4494	>	(BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4495	>	return ForkJoinTasks.reduceEntries
4496	>	(this, reducer).invoke();
4497	>	}
4498	>
4499	>	/**
4500	>	* Returns the result of accumulating the given transformation
4501	>	* of all entries using the given reducer to combine values,
4502	>	* or null if none.
4503	>	*
4504	>	* @param transformer a function returning the transformation
4505	>	* for an element, or null of there is no transformation (in
4506	>	* which case it is not combined).
4507	>	* @param reducer a commutative associative combining function
4508	>	* @return the result of accumulating the given transformation
4509	>	* of all entries
4510	>	*/
4511	>	public <U> U reduceEntriesInParallel
4512	>	(Fun<Map.Entry<K,V>, ? extends U> transformer,
4513	>	BiFun<? super U, ? super U, ? extends U> reducer) {
4514	>	return ForkJoinTasks.reduceEntries
4515	>	(this, transformer, reducer).invoke();
4516	>	}
4517	>
4518	>	/**
4519	>	* Returns the result of accumulating the given transformation
4520	>	* of all entries using the given reducer to combine values,
4521	>	* and the given basis as an identity value.
4522	>	*
4523	>	* @param transformer a function returning the transformation
4524	>	* for an element
4525	>	* @param basis the identity (initial default value) for the reduction
4526	>	* @param reducer a commutative associative combining function
4527	>	* @return the result of accumulating the given transformation
4528	>	* of all entries
4529	>	*/
4530	>	public double reduceEntriesToDoubleInParallel
4531	>	(ObjectToDouble<Map.Entry<K,V>> transformer,
4532	>	double basis,
4533	>	DoubleByDoubleToDouble reducer) {
4534	>	return ForkJoinTasks.reduceEntriesToDouble
4535	>	(this, transformer, basis, reducer).invoke();
4536	>	}
4537	>
4538	>	/**
4539	>	* Returns the result of accumulating the given transformation
4540	>	* of all entries using the given reducer to combine values,
4541	>	* and the given basis as an identity value.
4542	>	*
4543	>	* @param transformer a function returning the transformation
4544	>	* for an element
4545	>	* @param basis the identity (initial default value) for the reduction
4546	>	* @param reducer a commutative associative combining function
4547	>	* @return  the result of accumulating the given transformation
4548	>	* of all entries
4549	>	*/
4550	>	public long reduceEntriesToLongInParallel
4551	>	(ObjectToLong<Map.Entry<K,V>> transformer,
4552	>	long basis,
4553	>	LongByLongToLong reducer) {
4554	>	return ForkJoinTasks.reduceEntriesToLong
4555	>	(this, transformer, basis, reducer).invoke();
4556	>	}
4557	>
4558	>	/**
4559	>	* Returns the result of accumulating the given transformation
4560	>	* of all entries using the given reducer to combine values,
4561	>	* and the given basis as an identity value.
4562	>	*
4563	>	* @param transformer a function returning the transformation
4564	>	* for an element
4565	>	* @param basis the identity (initial default value) for the reduction
4566	>	* @param reducer a commutative associative combining function
4567	>	* @return the result of accumulating the given transformation
4568	>	* of all entries
4569	>	*/
4570	>	public int reduceEntriesToIntInParallel
4571	>	(ObjectToInt<Map.Entry<K,V>> transformer,
4572	>	int basis,
4573	>	IntByIntToInt reducer) {
4574	>	return ForkJoinTasks.reduceEntriesToInt
4575	>	(this, transformer, basis, reducer).invoke();
4576	>	}
4577	>
4578	>
4579	>	/* ----------------Views -------------- */
4580	>
4581	>	/**
4582	>	* Base class for views.
4583	>	*/
4584	>	static abstract class CHMView<K, V> {
4585	>	final ConcurrentHashMap<K, V> map;
4586	>	CHMView(ConcurrentHashMap<K, V> map)  { this.map = map; }
4587	>
4588	>	/**
4589	>	* Returns the map backing this view.
4590	>	*
4591	>	* @return the map backing this view
4592	>	*/
4593	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4594	>
4595	>	public final int size()                 { return map.size(); }
4596	>	public final boolean isEmpty()          { return map.isEmpty(); }
4597	>	public final void clear()               { map.clear(); }
4598	>
4599	>	// implementations below rely on concrete classes supplying these
4600	>	abstract public Iterator<?> iterator();
4601	>	abstract public boolean contains(Object o);
4602	>	abstract public boolean remove(Object o);
4603	>
4604	>	private static final String oomeMsg = "Required array size too large";
4605	>
4606	>	public final Object[] toArray() {
4607	>	long sz = map.mappingCount();
4608	>	if (sz > (long)(MAX_ARRAY_SIZE))
4609	>	throw new OutOfMemoryError(oomeMsg);
4610	>	int n = (int)sz;
4611	>	Object[] r = new Object[n];
4612	>	int i = 0;
4613	>	Iterator<?> it = iterator();
4614	>	while (it.hasNext()) {
4615	>	if (i == n) {
4616	>	if (n >= MAX_ARRAY_SIZE)
4617	>	throw new OutOfMemoryError(oomeMsg);
4618	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4619	>	n = MAX_ARRAY_SIZE;
4620	>	else
4621	>	n += (n >>> 1) + 1;
4622	>	r = Arrays.copyOf(r, n);
4623	>	}
4624	>	r[i++] = it.next();
4625	>	}
4626	>	return (i == n) ? r : Arrays.copyOf(r, i);
4627	>	}
4628	>
4629	>	@SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
4630	>	long sz = map.mappingCount();
4631	>	if (sz > (long)(MAX_ARRAY_SIZE))
4632	>	throw new OutOfMemoryError(oomeMsg);
4633	>	int m = (int)sz;
4634	>	T[] r = (a.length >= m) ? a :
4635	>	(T[])java.lang.reflect.Array
4636	>	.newInstance(a.getClass().getComponentType(), m);
4637	>	int n = r.length;
4638	>	int i = 0;
4639	>	Iterator<?> it = iterator();
4640	>	while (it.hasNext()) {
4641	>	if (i == n) {
4642	>	if (n >= MAX_ARRAY_SIZE)
4643	>	throw new OutOfMemoryError(oomeMsg);
4644	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4645	>	n = MAX_ARRAY_SIZE;
4646	>	else
4647	>	n += (n >>> 1) + 1;
4648	>	r = Arrays.copyOf(r, n);
4649	>	}
4650	>	r[i++] = (T)it.next();
4651	>	}
4652	>	if (a == r && i < n) {
4653	>	r[i] = null; // null-terminate
4654	>	return r;
4655	>	}
4656	>	return (i == n) ? r : Arrays.copyOf(r, i);
4657	>	}
4658	>
4659	>	public final int hashCode() {
4660	>	int h = 0;
4661	>	for (Iterator<?> it = iterator(); it.hasNext();)
4662	>	h += it.next().hashCode();
4663	>	return h;
4664	>	}
4665	>
4666	>	public final String toString() {
4667	>	StringBuilder sb = new StringBuilder();
4668	>	sb.append('[');
4669	>	Iterator<?> it = iterator();
4670	>	if (it.hasNext()) {
4671	>	for (;;) {
4672	>	Object e = it.next();
4673	>	sb.append(e == this ? "(this Collection)" : e);
4674	>	if (!it.hasNext())
4675	>	break;
4676	>	sb.append(',').append(' ');
4677	>	}
4678	>	}
4679	>	return sb.append(']').toString();
4680	>	}
4681	>
4682	>	public final boolean containsAll(Collection<?> c) {
4683	>	if (c != this) {
4684	>	for (Iterator<?> it = c.iterator(); it.hasNext();) {
4685	>	Object e = it.next();
4686	>	if (e == null || !contains(e))
4687	>	return false;
4688	>	}
4689	>	}
4690	>	return true;
4691	>	}
4692	>
4693	>	public final boolean removeAll(Collection<?> c) {
4694	>	boolean modified = false;
4695	>	for (Iterator<?> it = iterator(); it.hasNext();) {
4696	>	if (c.contains(it.next())) {
4697	>	it.remove();
4698	>	modified = true;
4699	>	}
4700	>	}
4701	>	return modified;
4702	>	}
4703	>
4704	>	public final boolean retainAll(Collection<?> c) {
4705	>	boolean modified = false;
4706	>	for (Iterator<?> it = iterator(); it.hasNext();) {
4707	>	if (!c.contains(it.next())) {
4708	>	it.remove();
4709	>	modified = true;
4710	>	}
4711	>	}
4712	>	return modified;
4713	>	}
4714	>
4715	>	}
4716	>
4717	>	/**
4718	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4719	>	* which additions may optionally be enabled by mapping to a
4720	>	* common value.  This class cannot be directly instantiated. See
4721	>	* {@link #keySet}, {@link #keySet(Object)}, {@link #newKeySet()},
4722	>	* {@link #newKeySet(int)}.
4723	>	*/
4724	>	public static class KeySetView<K,V> extends CHMView<K,V>
4725	>	implements Set<K>, java.io.Serializable {
4726	>	private static final long serialVersionUID = 7249069246763182397L;
4727	>	private final V value;
4728	>	KeySetView(ConcurrentHashMap<K, V> map, V value) {  // non-public
4729	>	super(map);
4730	>	this.value = value;
4731	>	}
4732	>
4733	>	/**
4734	>	* Returns the default mapped value for additions,
4735	>	* or {@code null} if additions are not supported.
4736	>	*
4737	>	* @return the default mapped value for additions, or {@code null}
4738	>	* if not supported.
4739	>	*/
4740	>	public V getMappedValue() { return value; }
4741	>
4742	>	// implement Set API
4743	>
4744	>	public boolean contains(Object o) { return map.containsKey(o); }
4745	>	public boolean remove(Object o)   { return map.remove(o) != null; }
4746	>
4747	>	/**
4748	>	* Returns a "weakly consistent" iterator that will never
4749	>	* throw {@link ConcurrentModificationException}, and
4750	>	* guarantees to traverse elements as they existed upon
4751	>	* construction of the iterator, and may (but is not
4752	>	* guaranteed to) reflect any modifications subsequent to
4753	>	* construction.
4754	>	*
4755	>	* @return an iterator over the keys of this map
4756	>	*/
4757	>	public Iterator<K> iterator()     { return new KeyIterator<K,V>(map); }
4758	>	public boolean add(K e) {
4759	>	V v;
4760	>	if ((v = value) == null)
4761	>	throw new UnsupportedOperationException();
4762	>	if (e == null)
4763	>	throw new NullPointerException();
4764	>	return map.internalPut(e, v, true) == null;
4765	>	}
4766	>	public boolean addAll(Collection<? extends K> c) {
4767	>	boolean added = false;
4768	>	V v;
4769	>	if ((v = value) == null)
4770	>	throw new UnsupportedOperationException();
4771	>	for (K e : c) {
4772	>	if (e == null)
4773	>	throw new NullPointerException();
4774	>	if (map.internalPut(e, v, true) == null)
4775	>	added = true;
4776	>	}
4777	>	return added;
4778	>	}
4779	>	public boolean equals(Object o) {
4780	>	Set<?> c;
4781	>	return ((o instanceof Set) &&
4782	>	((c = (Set<?>)o) == this ||
4783	>	(containsAll(c) && c.containsAll(this))));
4784	>	}
4785	>	}
4786	>
4787	>	/**
4788	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4789	>	* values, in which additions are disabled. This class cannot be
4790	>	* directly instantiated. See {@link #values},
4791	>	*
4792	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
4793	>	* that will never throw {@link ConcurrentModificationException},
4794	>	* and guarantees to traverse elements as they existed upon
4795	>	* construction of the iterator, and may (but is not guaranteed to)
4796	>	* reflect any modifications subsequent to construction.
4797	>	*/
4798	>	public static final class ValuesView<K,V> extends CHMView<K,V>
4799	>	implements Collection<V> {
4800	>	ValuesView(ConcurrentHashMap<K, V> map)   { super(map); }
4801	>	public final boolean contains(Object o) { return map.containsValue(o); }
4802	>	public final boolean remove(Object o) {
4803	>	if (o != null) {
4804	>	Iterator<V> it = new ValueIterator<K,V>(map);
4805	>	while (it.hasNext()) {
4806	>	if (o.equals(it.next())) {
4807	>	it.remove();
4808	>	return true;
4809		}
4810		}
1427	–	} finally {
1428	–	seg.unlock();
4811		}
4812	+	return false;
4813		}
4814	<	s.writeObject(null);
4815	<	s.writeObject(null);
4814	>
4815	>	/**
4816	>	* Returns a "weakly consistent" iterator that will never
4817	>	* throw {@link ConcurrentModificationException}, and
4818	>	* guarantees to traverse elements as they existed upon
4819	>	* construction of the iterator, and may (but is not
4820	>	* guaranteed to) reflect any modifications subsequent to
4821	>	* construction.
4822	>	*
4823	>	* @return an iterator over the values of this map
4824	>	*/
4825	>	public final Iterator<V> iterator() {
4826	>	return new ValueIterator<K,V>(map);
4827	>	}
4828	>	public final boolean add(V e) {
4829	>	throw new UnsupportedOperationException();
4830	>	}
4831	>	public final boolean addAll(Collection<? extends V> c) {
4832	>	throw new UnsupportedOperationException();
4833	>	}
4834	>
4835		}
4836
4837		/**
4838	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
4839	<	* stream (i.e., deserializes it).
4840	<	* @param s the stream
4838	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4839	>	* entries.  This class cannot be directly instantiated. See
4840	>	* {@link #entrySet}.
4841		*/
4842	<	@SuppressWarnings("unchecked")
4843	<	private void readObject(java.io.ObjectInputStream s)
4844	<	throws IOException, ClassNotFoundException {
4845	<	s.defaultReadObject();
4842	>	public static final class EntrySetView<K,V> extends CHMView<K,V>
4843	>	implements Set<Map.Entry<K,V>> {
4844	>	EntrySetView(ConcurrentHashMap<K, V> map) { super(map); }
4845	>	public final boolean contains(Object o) {
4846	>	Object k, v, r; Map.Entry<?,?> e;
4847	>	return ((o instanceof Map.Entry) &&
4848	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4849	>	(r = map.get(k)) != null &&
4850	>	(v = e.getValue()) != null &&
4851	>	(v == r || v.equals(r)));
4852	>	}
4853	>	public final boolean remove(Object o) {
4854	>	Object k, v; Map.Entry<?,?> e;
4855	>	return ((o instanceof Map.Entry) &&
4856	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4857	>	(v = e.getValue()) != null &&
4858	>	map.remove(k, v));
4859	>	}
4860
4861	<	// Re-initialize segments to be minimally sized, and let grow.
4862	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
4863	<	final Segment<K,V>[] segments = this.segments;
4864	<	for (int k = 0; k < segments.length; ++k) {
4865	<	Segment<K,V> seg = segments[k];
4866	<	if (seg != null) {
4867	<	seg.threshold = (int)(cap * seg.loadFactor);
4868	<	seg.table = (HashEntry<K,V>[]) new HashEntry[cap];
4861	>	/**
4862	>	* Returns a "weakly consistent" iterator that will never
4863	>	* throw {@link ConcurrentModificationException}, and
4864	>	* guarantees to traverse elements as they existed upon
4865	>	* construction of the iterator, and may (but is not
4866	>	* guaranteed to) reflect any modifications subsequent to
4867	>	* construction.
4868	>	*
4869	>	* @return an iterator over the entries of this map
4870	>	*/
4871	>	public final Iterator<Map.Entry<K,V>> iterator() {
4872	>	return new EntryIterator<K,V>(map);
4873	>	}
4874	>
4875	>	public final boolean add(Entry<K,V> e) {
4876	>	K key = e.getKey();
4877	>	V value = e.getValue();
4878	>	if (key == null || value == null)
4879	>	throw new NullPointerException();
4880	>	return map.internalPut(key, value, false) == null;
4881	>	}
4882	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
4883	>	boolean added = false;
4884	>	for (Entry<K,V> e : c) {
4885	>	if (add(e))
4886	>	added = true;
4887		}
4888	+	return added;
4889	+	}
4890	+	public boolean equals(Object o) {
4891	+	Set<?> c;
4892	+	return ((o instanceof Set) &&
4893	+	((c = (Set<?>)o) == this ||
4894	+	(containsAll(c) && c.containsAll(this))));
4895		}
4896	+	}
4897
4898	<	// Read the keys and values, and put the mappings in the table
4899	<	for (;;) {
4900	<	K key = (K) s.readObject();
4901	<	V value = (V) s.readObject();
4902	<	if (key == null)
4903	<	break;
4904	<	put(key, value);
4898	>	// ---------------------------------------------------------------------
4899	>
4900	>	/**
4901	>	* Predefined tasks for performing bulk parallel operations on
4902	>	* ConcurrentHashMaps. These tasks follow the forms and rules used
4903	>	* for bulk operations. Each method has the same name, but returns
4904	>	* a task rather than invoking it. These methods may be useful in
4905	>	* custom applications such as submitting a task without waiting
4906	>	* for completion, using a custom pool, or combining with other
4907	>	* tasks.
4908	>	*/
4909	>	public static class ForkJoinTasks {
4910	>	private ForkJoinTasks() {}
4911	>
4912	>	/**
4913	>	* Returns a task that when invoked, performs the given
4914	>	* action for each (key, value)
4915	>	*
4916	>	* @param map the map
4917	>	* @param action the action
4918	>	* @return the task
4919	>	*/
4920	>	public static <K,V> ForkJoinTask<Void> forEach
4921	>	(ConcurrentHashMap<K,V> map,
4922	>	BiAction<K,V> action) {
4923	>	if (action == null) throw new NullPointerException();
4924	>	return new ForEachMappingTask<K,V>(map, null, -1, action);
4925	>	}
4926	>
4927	>	/**
4928	>	* Returns a task that when invoked, performs the given
4929	>	* action for each non-null transformation of each (key, value)
4930	>	*
4931	>	* @param map the map
4932	>	* @param transformer a function returning the transformation
4933	>	* for an element, or null if there is no transformation (in
4934	>	* which case the action is not applied)
4935	>	* @param action the action
4936	>	* @return the task
4937	>	*/
4938	>	public static <K,V,U> ForkJoinTask<Void> forEach
4939	>	(ConcurrentHashMap<K,V> map,
4940	>	BiFun<? super K, ? super V, ? extends U> transformer,
4941	>	Action<U> action) {
4942	>	if (transformer == null || action == null)
4943	>	throw new NullPointerException();
4944	>	return new ForEachTransformedMappingTask<K,V,U>
4945	>	(map, null, -1, transformer, action);
4946	>	}
4947	>
4948	>	/**
4949	>	* Returns a task that when invoked, returns a non-null result
4950	>	* from applying the given search function on each (key,
4951	>	* value), or null if none. Upon success, further element
4952	>	* processing is suppressed and the results of any other
4953	>	* parallel invocations of the search function are ignored.
4954	>	*
4955	>	* @param map the map
4956	>	* @param searchFunction a function returning a non-null
4957	>	* result on success, else null
4958	>	* @return the task
4959	>	*/
4960	>	public static <K,V,U> ForkJoinTask<U> search
4961	>	(ConcurrentHashMap<K,V> map,
4962	>	BiFun<? super K, ? super V, ? extends U> searchFunction) {
4963	>	if (searchFunction == null) throw new NullPointerException();
4964	>	return new SearchMappingsTask<K,V,U>
4965	>	(map, null, -1, searchFunction,
4966	>	new AtomicReference<U>());
4967	>	}
4968	>
4969	>	/**
4970	>	* Returns a task that when invoked, returns the result of
4971	>	* accumulating the given transformation of all (key, value) pairs
4972	>	* using the given reducer to combine values, or null if none.
4973	>	*
4974	>	* @param map the map
4975	>	* @param transformer a function returning the transformation
4976	>	* for an element, or null if there is no transformation (in
4977	>	* which case it is not combined).
4978	>	* @param reducer a commutative associative combining function
4979	>	* @return the task
4980	>	*/
4981	>	public static <K,V,U> ForkJoinTask<U> reduce
4982	>	(ConcurrentHashMap<K,V> map,
4983	>	BiFun<? super K, ? super V, ? extends U> transformer,
4984	>	BiFun<? super U, ? super U, ? extends U> reducer) {
4985	>	if (transformer == null || reducer == null)
4986	>	throw new NullPointerException();
4987	>	return new MapReduceMappingsTask<K,V,U>
4988	>	(map, null, -1, null, transformer, reducer);
4989	>	}
4990	>
4991	>	/**
4992	>	* Returns a task that when invoked, returns the result of
4993	>	* accumulating the given transformation of all (key, value) pairs
4994	>	* using the given reducer to combine values, and the given
4995	>	* basis as an identity value.
4996	>	*
4997	>	* @param map the map
4998	>	* @param transformer a function returning the transformation
4999	>	* for an element
5000	>	* @param basis the identity (initial default value) for the reduction
5001	>	* @param reducer a commutative associative combining function
5002	>	* @return the task
5003	>	*/
5004	>	public static <K,V> ForkJoinTask<Double> reduceToDouble
5005	>	(ConcurrentHashMap<K,V> map,
5006	>	ObjectByObjectToDouble<? super K, ? super V> transformer,
5007	>	double basis,
5008	>	DoubleByDoubleToDouble reducer) {
5009	>	if (transformer == null || reducer == null)
5010	>	throw new NullPointerException();
5011	>	return new MapReduceMappingsToDoubleTask<K,V>
5012	>	(map, null, -1, null, transformer, basis, reducer);
5013	>	}
5014	>
5015	>	/**
5016	>	* Returns a task that when invoked, returns the result of
5017	>	* accumulating the given transformation of all (key, value) pairs
5018	>	* using the given reducer to combine values, and the given
5019	>	* basis as an identity value.
5020	>	*
5021	>	* @param map the map
5022	>	* @param transformer a function returning the transformation
5023	>	* for an element
5024	>	* @param basis the identity (initial default value) for the reduction
5025	>	* @param reducer a commutative associative combining function
5026	>	* @return the task
5027	>	*/
5028	>	public static <K,V> ForkJoinTask<Long> reduceToLong
5029	>	(ConcurrentHashMap<K,V> map,
5030	>	ObjectByObjectToLong<? super K, ? super V> transformer,
5031	>	long basis,
5032	>	LongByLongToLong reducer) {
5033	>	if (transformer == null || reducer == null)
5034	>	throw new NullPointerException();
5035	>	return new MapReduceMappingsToLongTask<K,V>
5036	>	(map, null, -1, null, transformer, basis, reducer);
5037	>	}
5038	>
5039	>	/**
5040	>	* Returns a task that when invoked, returns the result of
5041	>	* accumulating the given transformation of all (key, value) pairs
5042	>	* using the given reducer to combine values, and the given
5043	>	* basis as an identity value.
5044	>	*
5045	>	* @param transformer a function returning the transformation
5046	>	* for an element
5047	>	* @param basis the identity (initial default value) for the reduction
5048	>	* @param reducer a commutative associative combining function
5049	>	* @return the task
5050	>	*/
5051	>	public static <K,V> ForkJoinTask<Integer> reduceToInt
5052	>	(ConcurrentHashMap<K,V> map,
5053	>	ObjectByObjectToInt<? super K, ? super V> transformer,
5054	>	int basis,
5055	>	IntByIntToInt reducer) {
5056	>	if (transformer == null || reducer == null)
5057	>	throw new NullPointerException();
5058	>	return new MapReduceMappingsToIntTask<K,V>
5059	>	(map, null, -1, null, transformer, basis, reducer);
5060	>	}
5061	>
5062	>	/**
5063	>	* Returns a task that when invoked, performs the given action
5064	>	* for each key.
5065	>	*
5066	>	* @param map the map
5067	>	* @param action the action
5068	>	* @return the task
5069	>	*/
5070	>	public static <K,V> ForkJoinTask<Void> forEachKey
5071	>	(ConcurrentHashMap<K,V> map,
5072	>	Action<K> action) {
5073	>	if (action == null) throw new NullPointerException();
5074	>	return new ForEachKeyTask<K,V>(map, null, -1, action);
5075	>	}
5076	>
5077	>	/**
5078	>	* Returns a task that when invoked, performs the given action
5079	>	* for each non-null transformation of each key.
5080	>	*
5081	>	* @param map the map
5082	>	* @param transformer a function returning the transformation
5083	>	* for an element, or null if there is no transformation (in
5084	>	* which case the action is not applied)
5085	>	* @param action the action
5086	>	* @return the task
5087	>	*/
5088	>	public static <K,V,U> ForkJoinTask<Void> forEachKey
5089	>	(ConcurrentHashMap<K,V> map,
5090	>	Fun<? super K, ? extends U> transformer,
5091	>	Action<U> action) {
5092	>	if (transformer == null || action == null)
5093	>	throw new NullPointerException();
5094	>	return new ForEachTransformedKeyTask<K,V,U>
5095	>	(map, null, -1, transformer, action);
5096	>	}
5097	>
5098	>	/**
5099	>	* Returns a task that when invoked, returns a non-null result
5100	>	* from applying the given search function on each key, or
5101	>	* null if none.  Upon success, further element processing is
5102	>	* suppressed and the results of any other parallel
5103	>	* invocations of the search function are ignored.
5104	>	*
5105	>	* @param map the map
5106	>	* @param searchFunction a function returning a non-null
5107	>	* result on success, else null
5108	>	* @return the task
5109	>	*/
5110	>	public static <K,V,U> ForkJoinTask<U> searchKeys
5111	>	(ConcurrentHashMap<K,V> map,
5112	>	Fun<? super K, ? extends U> searchFunction) {
5113	>	if (searchFunction == null) throw new NullPointerException();
5114	>	return new SearchKeysTask<K,V,U>
5115	>	(map, null, -1, searchFunction,
5116	>	new AtomicReference<U>());
5117	>	}
5118	>
5119	>	/**
5120	>	* Returns a task that when invoked, returns the result of
5121	>	* accumulating all keys using the given reducer to combine
5122	>	* values, or null if none.
5123	>	*
5124	>	* @param map the map
5125	>	* @param reducer a commutative associative combining function
5126	>	* @return the task
5127	>	*/
5128	>	public static <K,V> ForkJoinTask<K> reduceKeys
5129	>	(ConcurrentHashMap<K,V> map,
5130	>	BiFun<? super K, ? super K, ? extends K> reducer) {
5131	>	if (reducer == null) throw new NullPointerException();
5132	>	return new ReduceKeysTask<K,V>
5133	>	(map, null, -1, null, reducer);
5134	>	}
5135	>
5136	>	/**
5137	>	* Returns a task that when invoked, returns the result of
5138	>	* accumulating the given transformation of all keys using the given
5139	>	* reducer to combine values, or null if none.
5140	>	*
5141	>	* @param map the map
5142	>	* @param transformer a function returning the transformation
5143	>	* for an element, or null if there is no transformation (in
5144	>	* which case it is not combined).
5145	>	* @param reducer a commutative associative combining function
5146	>	* @return the task
5147	>	*/
5148	>	public static <K,V,U> ForkJoinTask<U> reduceKeys
5149	>	(ConcurrentHashMap<K,V> map,
5150	>	Fun<? super K, ? extends U> transformer,
5151	>	BiFun<? super U, ? super U, ? extends U> reducer) {
5152	>	if (transformer == null || reducer == null)
5153	>	throw new NullPointerException();
5154	>	return new MapReduceKeysTask<K,V,U>
5155	>	(map, null, -1, null, transformer, reducer);
5156	>	}
5157	>
5158	>	/**
5159	>	* Returns a task that when invoked, returns the result of
5160	>	* accumulating the given transformation of all keys using the given
5161	>	* reducer to combine values, and the given basis as an
5162	>	* identity value.
5163	>	*
5164	>	* @param map the map
5165	>	* @param transformer a function returning the transformation
5166	>	* for an element
5167	>	* @param basis the identity (initial default value) for the reduction
5168	>	* @param reducer a commutative associative combining function
5169	>	* @return the task
5170	>	*/
5171	>	public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
5172	>	(ConcurrentHashMap<K,V> map,
5173	>	ObjectToDouble<? super K> transformer,
5174	>	double basis,
5175	>	DoubleByDoubleToDouble reducer) {
5176	>	if (transformer == null || reducer == null)
5177	>	throw new NullPointerException();
5178	>	return new MapReduceKeysToDoubleTask<K,V>
5179	>	(map, null, -1, null, transformer, basis, reducer);
5180	>	}
5181	>
5182	>	/**
5183	>	* Returns a task that when invoked, returns the result of
5184	>	* accumulating the given transformation of all keys using the given
5185	>	* reducer to combine values, and the given basis as an
5186	>	* identity value.
5187	>	*
5188	>	* @param map the map
5189	>	* @param transformer a function returning the transformation
5190	>	* for an element
5191	>	* @param basis the identity (initial default value) for the reduction
5192	>	* @param reducer a commutative associative combining function
5193	>	* @return the task
5194	>	*/
5195	>	public static <K,V> ForkJoinTask<Long> reduceKeysToLong
5196	>	(ConcurrentHashMap<K,V> map,
5197	>	ObjectToLong<? super K> transformer,
5198	>	long basis,
5199	>	LongByLongToLong reducer) {
5200	>	if (transformer == null || reducer == null)
5201	>	throw new NullPointerException();
5202	>	return new MapReduceKeysToLongTask<K,V>
5203	>	(map, null, -1, null, transformer, basis, reducer);
5204	>	}
5205	>
5206	>	/**
5207	>	* Returns a task that when invoked, returns the result of
5208	>	* accumulating the given transformation of all keys using the given
5209	>	* reducer to combine values, and the given basis as an
5210	>	* identity value.
5211	>	*
5212	>	* @param map the map
5213	>	* @param transformer a function returning the transformation
5214	>	* for an element
5215	>	* @param basis the identity (initial default value) for the reduction
5216	>	* @param reducer a commutative associative combining function
5217	>	* @return the task
5218	>	*/
5219	>	public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
5220	>	(ConcurrentHashMap<K,V> map,
5221	>	ObjectToInt<? super K> transformer,
5222	>	int basis,
5223	>	IntByIntToInt reducer) {
5224	>	if (transformer == null || reducer == null)
5225	>	throw new NullPointerException();
5226	>	return new MapReduceKeysToIntTask<K,V>
5227	>	(map, null, -1, null, transformer, basis, reducer);
5228	>	}
5229	>
5230	>	/**
5231	>	* Returns a task that when invoked, performs the given action
5232	>	* for each value.
5233	>	*
5234	>	* @param map the map
5235	>	* @param action the action
5236	>	*/
5237	>	public static <K,V> ForkJoinTask<Void> forEachValue
5238	>	(ConcurrentHashMap<K,V> map,
5239	>	Action<V> action) {
5240	>	if (action == null) throw new NullPointerException();
5241	>	return new ForEachValueTask<K,V>(map, null, -1, action);
5242	>	}
5243	>
5244	>	/**
5245	>	* Returns a task that when invoked, performs the given action
5246	>	* for each non-null transformation of each value.
5247	>	*
5248	>	* @param map the map
5249	>	* @param transformer a function returning the transformation
5250	>	* for an element, or null if there is no transformation (in
5251	>	* which case the action is not applied)
5252	>	* @param action the action
5253	>	*/
5254	>	public static <K,V,U> ForkJoinTask<Void> forEachValue
5255	>	(ConcurrentHashMap<K,V> map,
5256	>	Fun<? super V, ? extends U> transformer,
5257	>	Action<U> action) {
5258	>	if (transformer == null || action == null)
5259	>	throw new NullPointerException();
5260	>	return new ForEachTransformedValueTask<K,V,U>
5261	>	(map, null, -1, transformer, action);
5262	>	}
5263	>
5264	>	/**
5265	>	* Returns a task that when invoked, returns a non-null result
5266	>	* from applying the given search function on each value, or
5267	>	* null if none.  Upon success, further element processing is
5268	>	* suppressed and the results of any other parallel
5269	>	* invocations of the search function are ignored.
5270	>	*
5271	>	* @param map the map
5272	>	* @param searchFunction a function returning a non-null
5273	>	* result on success, else null
5274	>	* @return the task
5275	>	*/
5276	>	public static <K,V,U> ForkJoinTask<U> searchValues
5277	>	(ConcurrentHashMap<K,V> map,
5278	>	Fun<? super V, ? extends U> searchFunction) {
5279	>	if (searchFunction == null) throw new NullPointerException();
5280	>	return new SearchValuesTask<K,V,U>
5281	>	(map, null, -1, searchFunction,
5282	>	new AtomicReference<U>());
5283	>	}
5284	>
5285	>	/**
5286	>	* Returns a task that when invoked, returns the result of
5287	>	* accumulating all values using the given reducer to combine
5288	>	* values, or null if none.
5289	>	*
5290	>	* @param map the map
5291	>	* @param reducer a commutative associative combining function
5292	>	* @return the task
5293	>	*/
5294	>	public static <K,V> ForkJoinTask<V> reduceValues
5295	>	(ConcurrentHashMap<K,V> map,
5296	>	BiFun<? super V, ? super V, ? extends V> reducer) {
5297	>	if (reducer == null) throw new NullPointerException();
5298	>	return new ReduceValuesTask<K,V>
5299	>	(map, null, -1, null, reducer);
5300	>	}
5301	>
5302	>	/**
5303	>	* Returns a task that when invoked, returns the result of
5304	>	* accumulating the given transformation of all values using the
5305	>	* given reducer to combine values, or null if none.
5306	>	*
5307	>	* @param map the map
5308	>	* @param transformer a function returning the transformation
5309	>	* for an element, or null if there is no transformation (in
5310	>	* which case it is not combined).
5311	>	* @param reducer a commutative associative combining function
5312	>	* @return the task
5313	>	*/
5314	>	public static <K,V,U> ForkJoinTask<U> reduceValues
5315	>	(ConcurrentHashMap<K,V> map,
5316	>	Fun<? super V, ? extends U> transformer,
5317	>	BiFun<? super U, ? super U, ? extends U> reducer) {
5318	>	if (transformer == null || reducer == null)
5319	>	throw new NullPointerException();
5320	>	return new MapReduceValuesTask<K,V,U>
5321	>	(map, null, -1, null, transformer, reducer);
5322	>	}
5323	>
5324	>	/**
5325	>	* Returns a task that when invoked, returns the result of
5326	>	* accumulating the given transformation of all values using the
5327	>	* given reducer to combine values, and the given basis as an
5328	>	* identity value.
5329	>	*
5330	>	* @param map the map
5331	>	* @param transformer a function returning the transformation
5332	>	* for an element
5333	>	* @param basis the identity (initial default value) for the reduction
5334	>	* @param reducer a commutative associative combining function
5335	>	* @return the task
5336	>	*/
5337	>	public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
5338	>	(ConcurrentHashMap<K,V> map,
5339	>	ObjectToDouble<? super V> transformer,
5340	>	double basis,
5341	>	DoubleByDoubleToDouble reducer) {
5342	>	if (transformer == null || reducer == null)
5343	>	throw new NullPointerException();
5344	>	return new MapReduceValuesToDoubleTask<K,V>
5345	>	(map, null, -1, null, transformer, basis, reducer);
5346	>	}
5347	>
5348	>	/**
5349	>	* Returns a task that when invoked, returns the result of
5350	>	* accumulating the given transformation of all values using the
5351	>	* given reducer to combine values, and the given basis as an
5352	>	* identity value.
5353	>	*
5354	>	* @param map the map
5355	>	* @param transformer a function returning the transformation
5356	>	* for an element
5357	>	* @param basis the identity (initial default value) for the reduction
5358	>	* @param reducer a commutative associative combining function
5359	>	* @return the task
5360	>	*/
5361	>	public static <K,V> ForkJoinTask<Long> reduceValuesToLong
5362	>	(ConcurrentHashMap<K,V> map,
5363	>	ObjectToLong<? super V> transformer,
5364	>	long basis,
5365	>	LongByLongToLong reducer) {
5366	>	if (transformer == null || reducer == null)
5367	>	throw new NullPointerException();
5368	>	return new MapReduceValuesToLongTask<K,V>
5369	>	(map, null, -1, null, transformer, basis, reducer);
5370	>	}
5371	>
5372	>	/**
5373	>	* Returns a task that when invoked, returns the result of
5374	>	* accumulating the given transformation of all values using the
5375	>	* given reducer to combine values, and the given basis as an
5376	>	* identity value.
5377	>	*
5378	>	* @param map the map
5379	>	* @param transformer a function returning the transformation
5380	>	* for an element
5381	>	* @param basis the identity (initial default value) for the reduction
5382	>	* @param reducer a commutative associative combining function
5383	>	* @return the task
5384	>	*/
5385	>	public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
5386	>	(ConcurrentHashMap<K,V> map,
5387	>	ObjectToInt<? super V> transformer,
5388	>	int basis,
5389	>	IntByIntToInt reducer) {
5390	>	if (transformer == null || reducer == null)
5391	>	throw new NullPointerException();
5392	>	return new MapReduceValuesToIntTask<K,V>
5393	>	(map, null, -1, null, transformer, basis, reducer);
5394	>	}
5395	>
5396	>	/**
5397	>	* Returns a task that when invoked, perform the given action
5398	>	* for each entry.
5399	>	*
5400	>	* @param map the map
5401	>	* @param action the action
5402	>	*/
5403	>	public static <K,V> ForkJoinTask<Void> forEachEntry
5404	>	(ConcurrentHashMap<K,V> map,
5405	>	Action<Map.Entry<K,V>> action) {
5406	>	if (action == null) throw new NullPointerException();
5407	>	return new ForEachEntryTask<K,V>(map, null, -1, action);
5408	>	}
5409	>
5410	>	/**
5411	>	* Returns a task that when invoked, perform the given action
5412	>	* for each non-null transformation of each entry.
5413	>	*
5414	>	* @param map the map
5415	>	* @param transformer a function returning the transformation
5416	>	* for an element, or null if there is no transformation (in
5417	>	* which case the action is not applied)
5418	>	* @param action the action
5419	>	*/
5420	>	public static <K,V,U> ForkJoinTask<Void> forEachEntry
5421	>	(ConcurrentHashMap<K,V> map,
5422	>	Fun<Map.Entry<K,V>, ? extends U> transformer,
5423	>	Action<U> action) {
5424	>	if (transformer == null || action == null)
5425	>	throw new NullPointerException();
5426	>	return new ForEachTransformedEntryTask<K,V,U>
5427	>	(map, null, -1, transformer, action);
5428	>	}
5429	>
5430	>	/**
5431	>	* Returns a task that when invoked, returns a non-null result
5432	>	* from applying the given search function on each entry, or
5433	>	* null if none.  Upon success, further element processing is
5434	>	* suppressed and the results of any other parallel
5435	>	* invocations of the search function are ignored.
5436	>	*
5437	>	* @param map the map
5438	>	* @param searchFunction a function returning a non-null
5439	>	* result on success, else null
5440	>	* @return the task
5441	>	*/
5442	>	public static <K,V,U> ForkJoinTask<U> searchEntries
5443	>	(ConcurrentHashMap<K,V> map,
5444	>	Fun<Map.Entry<K,V>, ? extends U> searchFunction) {
5445	>	if (searchFunction == null) throw new NullPointerException();
5446	>	return new SearchEntriesTask<K,V,U>
5447	>	(map, null, -1, searchFunction,
5448	>	new AtomicReference<U>());
5449	>	}
5450	>
5451	>	/**
5452	>	* Returns a task that when invoked, returns the result of
5453	>	* accumulating all entries using the given reducer to combine
5454	>	* values, or null if none.
5455	>	*
5456	>	* @param map the map
5457	>	* @param reducer a commutative associative combining function
5458	>	* @return the task
5459	>	*/
5460	>	public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
5461	>	(ConcurrentHashMap<K,V> map,
5462	>	BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5463	>	if (reducer == null) throw new NullPointerException();
5464	>	return new ReduceEntriesTask<K,V>
5465	>	(map, null, -1, null, reducer);
5466	>	}
5467	>
5468	>	/**
5469	>	* Returns a task that when invoked, returns the result of
5470	>	* accumulating the given transformation of all entries using the
5471	>	* given reducer to combine values, or null if none.
5472	>	*
5473	>	* @param map the map
5474	>	* @param transformer a function returning the transformation
5475	>	* for an element, or null if there is no transformation (in
5476	>	* which case it is not combined).
5477	>	* @param reducer a commutative associative combining function
5478	>	* @return the task
5479	>	*/
5480	>	public static <K,V,U> ForkJoinTask<U> reduceEntries
5481	>	(ConcurrentHashMap<K,V> map,
5482	>	Fun<Map.Entry<K,V>, ? extends U> transformer,
5483	>	BiFun<? super U, ? super U, ? extends U> reducer) {
5484	>	if (transformer == null || reducer == null)
5485	>	throw new NullPointerException();
5486	>	return new MapReduceEntriesTask<K,V,U>
5487	>	(map, null, -1, null, transformer, reducer);
5488	>	}
5489	>
5490	>	/**
5491	>	* Returns a task that when invoked, returns the result of
5492	>	* accumulating the given transformation of all entries using the
5493	>	* given reducer to combine values, and the given basis as an
5494	>	* identity value.
5495	>	*
5496	>	* @param map the map
5497	>	* @param transformer a function returning the transformation
5498	>	* for an element
5499	>	* @param basis the identity (initial default value) for the reduction
5500	>	* @param reducer a commutative associative combining function
5501	>	* @return the task
5502	>	*/
5503	>	public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
5504	>	(ConcurrentHashMap<K,V> map,
5505	>	ObjectToDouble<Map.Entry<K,V>> transformer,
5506	>	double basis,
5507	>	DoubleByDoubleToDouble reducer) {
5508	>	if (transformer == null || reducer == null)
5509	>	throw new NullPointerException();
5510	>	return new MapReduceEntriesToDoubleTask<K,V>
5511	>	(map, null, -1, null, transformer, basis, reducer);
5512	>	}
5513	>
5514	>	/**
5515	>	* Returns a task that when invoked, returns the result of
5516	>	* accumulating the given transformation of all entries using the
5517	>	* given reducer to combine values, and the given basis as an
5518	>	* identity value.
5519	>	*
5520	>	* @param map the map
5521	>	* @param transformer a function returning the transformation
5522	>	* for an element
5523	>	* @param basis the identity (initial default value) for the reduction
5524	>	* @param reducer a commutative associative combining function
5525	>	* @return the task
5526	>	*/
5527	>	public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
5528	>	(ConcurrentHashMap<K,V> map,
5529	>	ObjectToLong<Map.Entry<K,V>> transformer,
5530	>	long basis,
5531	>	LongByLongToLong reducer) {
5532	>	if (transformer == null || reducer == null)
5533	>	throw new NullPointerException();
5534	>	return new MapReduceEntriesToLongTask<K,V>
5535	>	(map, null, -1, null, transformer, basis, reducer);
5536	>	}
5537	>
5538	>	/**
5539	>	* Returns a task that when invoked, returns the result of
5540	>	* accumulating the given transformation of all entries using the
5541	>	* given reducer to combine values, and the given basis as an
5542	>	* identity value.
5543	>	*
5544	>	* @param map the map
5545	>	* @param transformer a function returning the transformation
5546	>	* for an element
5547	>	* @param basis the identity (initial default value) for the reduction
5548	>	* @param reducer a commutative associative combining function
5549	>	* @return the task
5550	>	*/
5551	>	public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
5552	>	(ConcurrentHashMap<K,V> map,
5553	>	ObjectToInt<Map.Entry<K,V>> transformer,
5554	>	int basis,
5555	>	IntByIntToInt reducer) {
5556	>	if (transformer == null || reducer == null)
5557	>	throw new NullPointerException();
5558	>	return new MapReduceEntriesToIntTask<K,V>
5559	>	(map, null, -1, null, transformer, basis, reducer);
5560	>	}
5561	>	}
5562	>
5563	>	// -------------------------------------------------------
5564	>
5565	>	/*
5566	>	* Task classes. Coded in a regular but ugly format/style to
5567	>	* simplify checks that each variant differs in the right way from
5568	>	* others. The null screenings exist because compilers cannot tell
5569	>	* that we've already null-checked task arguments, so we force
5570	>	* simplest hoisted bypass to help avoid convoluted traps.
5571	>	*/
5572	>
5573	>	@SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
5574	>	extends Traverser<K,V,Void> {
5575	>	final Action<K> action;
5576	>	ForEachKeyTask
5577	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5578	>	Action<K> action) {
5579	>	super(m, p, b);
5580	>	this.action = action;
5581	>	}
5582	>	@SuppressWarnings("unchecked") public final void compute() {
5583	>	final Action<K> action;
5584	>	if ((action = this.action) != null) {
5585	>	for (int b; (b = preSplit()) > 0;)
5586	>	new ForEachKeyTask<K,V>(map, this, b, action).fork();
5587	>	while (advance() != null)
5588	>	action.apply((K)nextKey);
5589	>	propagateCompletion();
5590	>	}
5591	>	}
5592	>	}
5593	>
5594	>	@SuppressWarnings("serial") static final class ForEachValueTask<K,V>
5595	>	extends Traverser<K,V,Void> {
5596	>	final Action<V> action;
5597	>	ForEachValueTask
5598	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5599	>	Action<V> action) {
5600	>	super(m, p, b);
5601	>	this.action = action;
5602	>	}
5603	>	@SuppressWarnings("unchecked") public final void compute() {
5604	>	final Action<V> action;
5605	>	if ((action = this.action) != null) {
5606	>	for (int b; (b = preSplit()) > 0;)
5607	>	new ForEachValueTask<K,V>(map, this, b, action).fork();
5608	>	V v;
5609	>	while ((v = advance()) != null)
5610	>	action.apply(v);
5611	>	propagateCompletion();
5612	>	}
5613	>	}
5614	>	}
5615	>
5616	>	@SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5617	>	extends Traverser<K,V,Void> {
5618	>	final Action<Entry<K,V>> action;
5619	>	ForEachEntryTask
5620	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5621	>	Action<Entry<K,V>> action) {
5622	>	super(m, p, b);
5623	>	this.action = action;
5624	>	}
5625	>	@SuppressWarnings("unchecked") public final void compute() {
5626	>	final Action<Entry<K,V>> action;
5627	>	if ((action = this.action) != null) {
5628	>	for (int b; (b = preSplit()) > 0;)
5629	>	new ForEachEntryTask<K,V>(map, this, b, action).fork();
5630	>	V v;
5631	>	while ((v = advance()) != null)
5632	>	action.apply(entryFor((K)nextKey, v));
5633	>	propagateCompletion();
5634	>	}
5635	>	}
5636	>	}
5637	>
5638	>	@SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5639	>	extends Traverser<K,V,Void> {
5640	>	final BiAction<K,V> action;
5641	>	ForEachMappingTask
5642	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5643	>	BiAction<K,V> action) {
5644	>	super(m, p, b);
5645	>	this.action = action;
5646	>	}
5647	>	@SuppressWarnings("unchecked") public final void compute() {
5648	>	final BiAction<K,V> action;
5649	>	if ((action = this.action) != null) {
5650	>	for (int b; (b = preSplit()) > 0;)
5651	>	new ForEachMappingTask<K,V>(map, this, b, action).fork();
5652	>	V v;
5653	>	while ((v = advance()) != null)
5654	>	action.apply((K)nextKey, v);
5655	>	propagateCompletion();
5656	>	}
5657	>	}
5658	>	}
5659	>
5660	>	@SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5661	>	extends Traverser<K,V,Void> {
5662	>	final Fun<? super K, ? extends U> transformer;
5663	>	final Action<U> action;
5664	>	ForEachTransformedKeyTask
5665	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5666	>	Fun<? super K, ? extends U> transformer, Action<U> action) {
5667	>	super(m, p, b);
5668	>	this.transformer = transformer; this.action = action;
5669	>	}
5670	>	@SuppressWarnings("unchecked") public final void compute() {
5671	>	final Fun<? super K, ? extends U> transformer;
5672	>	final Action<U> action;
5673	>	if ((transformer = this.transformer) != null &&
5674	>	(action = this.action) != null) {
5675	>	for (int b; (b = preSplit()) > 0;)
5676	>	new ForEachTransformedKeyTask<K,V,U>
5677	>	(map, this, b, transformer, action).fork();
5678	>	U u;
5679	>	while (advance() != null) {
5680	>	if ((u = transformer.apply((K)nextKey)) != null)
5681	>	action.apply(u);
5682	>	}
5683	>	propagateCompletion();
5684	>	}
5685	>	}
5686	>	}
5687	>
5688	>	@SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5689	>	extends Traverser<K,V,Void> {
5690	>	final Fun<? super V, ? extends U> transformer;
5691	>	final Action<U> action;
5692	>	ForEachTransformedValueTask
5693	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5694	>	Fun<? super V, ? extends U> transformer, Action<U> action) {
5695	>	super(m, p, b);
5696	>	this.transformer = transformer; this.action = action;
5697	>	}
5698	>	@SuppressWarnings("unchecked") public final void compute() {
5699	>	final Fun<? super V, ? extends U> transformer;
5700	>	final Action<U> action;
5701	>	if ((transformer = this.transformer) != null &&
5702	>	(action = this.action) != null) {
5703	>	for (int b; (b = preSplit()) > 0;)
5704	>	new ForEachTransformedValueTask<K,V,U>
5705	>	(map, this, b, transformer, action).fork();
5706	>	V v; U u;
5707	>	while ((v = advance()) != null) {
5708	>	if ((u = transformer.apply(v)) != null)
5709	>	action.apply(u);
5710	>	}
5711	>	propagateCompletion();
5712	>	}
5713	>	}
5714	>	}
5715	>
5716	>	@SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5717	>	extends Traverser<K,V,Void> {
5718	>	final Fun<Map.Entry<K,V>, ? extends U> transformer;
5719	>	final Action<U> action;
5720	>	ForEachTransformedEntryTask
5721	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5722	>	Fun<Map.Entry<K,V>, ? extends U> transformer, Action<U> action) {
5723	>	super(m, p, b);
5724	>	this.transformer = transformer; this.action = action;
5725	>	}
5726	>	@SuppressWarnings("unchecked") public final void compute() {
5727	>	final Fun<Map.Entry<K,V>, ? extends U> transformer;
5728	>	final Action<U> action;
5729	>	if ((transformer = this.transformer) != null &&
5730	>	(action = this.action) != null) {
5731	>	for (int b; (b = preSplit()) > 0;)
5732	>	new ForEachTransformedEntryTask<K,V,U>
5733	>	(map, this, b, transformer, action).fork();
5734	>	V v; U u;
5735	>	while ((v = advance()) != null) {
5736	>	if ((u = transformer.apply(entryFor((K)nextKey,
5737	>	v))) != null)
5738	>	action.apply(u);
5739	>	}
5740	>	propagateCompletion();
5741	>	}
5742	>	}
5743	>	}
5744	>
5745	>	@SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5746	>	extends Traverser<K,V,Void> {
5747	>	final BiFun<? super K, ? super V, ? extends U> transformer;
5748	>	final Action<U> action;
5749	>	ForEachTransformedMappingTask
5750	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5751	>	BiFun<? super K, ? super V, ? extends U> transformer,
5752	>	Action<U> action) {
5753	>	super(m, p, b);
5754	>	this.transformer = transformer; this.action = action;
5755	>	}
5756	>	@SuppressWarnings("unchecked") public final void compute() {
5757	>	final BiFun<? super K, ? super V, ? extends U> transformer;
5758	>	final Action<U> action;
5759	>	if ((transformer = this.transformer) != null &&
5760	>	(action = this.action) != null) {
5761	>	for (int b; (b = preSplit()) > 0;)
5762	>	new ForEachTransformedMappingTask<K,V,U>
5763	>	(map, this, b, transformer, action).fork();
5764	>	V v; U u;
5765	>	while ((v = advance()) != null) {
5766	>	if ((u = transformer.apply((K)nextKey, v)) != null)
5767	>	action.apply(u);
5768	>	}
5769	>	propagateCompletion();
5770	>	}
5771	>	}
5772	>	}
5773	>
5774	>	@SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5775	>	extends Traverser<K,V,U> {
5776	>	final Fun<? super K, ? extends U> searchFunction;
5777	>	final AtomicReference<U> result;
5778	>	SearchKeysTask
5779	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5780	>	Fun<? super K, ? extends U> searchFunction,
5781	>	AtomicReference<U> result) {
5782	>	super(m, p, b);
5783	>	this.searchFunction = searchFunction; this.result = result;
5784	>	}
5785	>	public final U getRawResult() { return result.get(); }
5786	>	@SuppressWarnings("unchecked") public final void compute() {
5787	>	final Fun<? super K, ? extends U> searchFunction;
5788	>	final AtomicReference<U> result;
5789	>	if ((searchFunction = this.searchFunction) != null &&
5790	>	(result = this.result) != null) {
5791	>	for (int b;;) {
5792	>	if (result.get() != null)
5793	>	return;
5794	>	if ((b = preSplit()) <= 0)
5795	>	break;
5796	>	new SearchKeysTask<K,V,U>
5797	>	(map, this, b, searchFunction, result).fork();
5798	>	}
5799	>	while (result.get() == null) {
5800	>	U u;
5801	>	if (advance() == null) {
5802	>	propagateCompletion();
5803	>	break;
5804	>	}
5805	>	if ((u = searchFunction.apply((K)nextKey)) != null) {
5806	>	if (result.compareAndSet(null, u))
5807	>	quietlyCompleteRoot();
5808	>	break;
5809	>	}
5810	>	}
5811	>	}
5812	>	}
5813	>	}
5814	>
5815	>	@SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5816	>	extends Traverser<K,V,U> {
5817	>	final Fun<? super V, ? extends U> searchFunction;
5818	>	final AtomicReference<U> result;
5819	>	SearchValuesTask
5820	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5821	>	Fun<? super V, ? extends U> searchFunction,
5822	>	AtomicReference<U> result) {
5823	>	super(m, p, b);
5824	>	this.searchFunction = searchFunction; this.result = result;
5825	>	}
5826	>	public final U getRawResult() { return result.get(); }
5827	>	@SuppressWarnings("unchecked") public final void compute() {
5828	>	final Fun<? super V, ? extends U> searchFunction;
5829	>	final AtomicReference<U> result;
5830	>	if ((searchFunction = this.searchFunction) != null &&
5831	>	(result = this.result) != null) {
5832	>	for (int b;;) {
5833	>	if (result.get() != null)
5834	>	return;
5835	>	if ((b = preSplit()) <= 0)
5836	>	break;
5837	>	new SearchValuesTask<K,V,U>
5838	>	(map, this, b, searchFunction, result).fork();
5839	>	}
5840	>	while (result.get() == null) {
5841	>	V v; U u;
5842	>	if ((v = advance()) == null) {
5843	>	propagateCompletion();
5844	>	break;
5845	>	}
5846	>	if ((u = searchFunction.apply(v)) != null) {
5847	>	if (result.compareAndSet(null, u))
5848	>	quietlyCompleteRoot();
5849	>	break;
5850	>	}
5851	>	}
5852	>	}
5853	>	}
5854	>	}
5855	>
5856	>	@SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5857	>	extends Traverser<K,V,U> {
5858	>	final Fun<Entry<K,V>, ? extends U> searchFunction;
5859	>	final AtomicReference<U> result;
5860	>	SearchEntriesTask
5861	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5862	>	Fun<Entry<K,V>, ? extends U> searchFunction,
5863	>	AtomicReference<U> result) {
5864	>	super(m, p, b);
5865	>	this.searchFunction = searchFunction; this.result = result;
5866	>	}
5867	>	public final U getRawResult() { return result.get(); }
5868	>	@SuppressWarnings("unchecked") public final void compute() {
5869	>	final Fun<Entry<K,V>, ? extends U> searchFunction;
5870	>	final AtomicReference<U> result;
5871	>	if ((searchFunction = this.searchFunction) != null &&
5872	>	(result = this.result) != null) {
5873	>	for (int b;;) {
5874	>	if (result.get() != null)
5875	>	return;
5876	>	if ((b = preSplit()) <= 0)
5877	>	break;
5878	>	new SearchEntriesTask<K,V,U>
5879	>	(map, this, b, searchFunction, result).fork();
5880	>	}
5881	>	while (result.get() == null) {
5882	>	V v; U u;
5883	>	if ((v = advance()) == null) {
5884	>	propagateCompletion();
5885	>	break;
5886	>	}
5887	>	if ((u = searchFunction.apply(entryFor((K)nextKey,
5888	>	v))) != null) {
5889	>	if (result.compareAndSet(null, u))
5890	>	quietlyCompleteRoot();
5891	>	return;
5892	>	}
5893	>	}
5894	>	}
5895	>	}
5896	>	}
5897	>
5898	>	@SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5899	>	extends Traverser<K,V,U> {
5900	>	final BiFun<? super K, ? super V, ? extends U> searchFunction;
5901	>	final AtomicReference<U> result;
5902	>	SearchMappingsTask
5903	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5904	>	BiFun<? super K, ? super V, ? extends U> searchFunction,
5905	>	AtomicReference<U> result) {
5906	>	super(m, p, b);
5907	>	this.searchFunction = searchFunction; this.result = result;
5908	>	}
5909	>	public final U getRawResult() { return result.get(); }
5910	>	@SuppressWarnings("unchecked") public final void compute() {
5911	>	final BiFun<? super K, ? super V, ? extends U> searchFunction;
5912	>	final AtomicReference<U> result;
5913	>	if ((searchFunction = this.searchFunction) != null &&
5914	>	(result = this.result) != null) {
5915	>	for (int b;;) {
5916	>	if (result.get() != null)
5917	>	return;
5918	>	if ((b = preSplit()) <= 0)
5919	>	break;
5920	>	new SearchMappingsTask<K,V,U>
5921	>	(map, this, b, searchFunction, result).fork();
5922	>	}
5923	>	while (result.get() == null) {
5924	>	V v; U u;
5925	>	if ((v = advance()) == null) {
5926	>	propagateCompletion();
5927	>	break;
5928	>	}
5929	>	if ((u = searchFunction.apply((K)nextKey, v)) != null) {
5930	>	if (result.compareAndSet(null, u))
5931	>	quietlyCompleteRoot();
5932	>	break;
5933	>	}
5934	>	}
5935	>	}
5936	>	}
5937	>	}
5938	>
5939	>	@SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5940	>	extends Traverser<K,V,K> {
5941	>	final BiFun<? super K, ? super K, ? extends K> reducer;
5942	>	K result;
5943	>	ReduceKeysTask<K,V> rights, nextRight;
5944	>	ReduceKeysTask
5945	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5946	>	ReduceKeysTask<K,V> nextRight,
5947	>	BiFun<? super K, ? super K, ? extends K> reducer) {
5948	>	super(m, p, b); this.nextRight = nextRight;
5949	>	this.reducer = reducer;
5950	>	}
5951	>	public final K getRawResult() { return result; }
5952	>	@SuppressWarnings("unchecked") public final void compute() {
5953	>	final BiFun<? super K, ? super K, ? extends K> reducer;
5954	>	if ((reducer = this.reducer) != null) {
5955	>	for (int b; (b = preSplit()) > 0;)
5956	>	(rights = new ReduceKeysTask<K,V>
5957	>	(map, this, b, rights, reducer)).fork();
5958	>	K r = null;
5959	>	while (advance() != null) {
5960	>	K u = (K)nextKey;
5961	>	r = (r == null) ? u : reducer.apply(r, u);
5962	>	}
5963	>	result = r;
5964	>	CountedCompleter<?> c;
5965	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5966	>	ReduceKeysTask<K,V>
5967	>	t = (ReduceKeysTask<K,V>)c,
5968	>	s = t.rights;
5969	>	while (s != null) {
5970	>	K tr, sr;
5971	>	if ((sr = s.result) != null)
5972	>	t.result = (((tr = t.result) == null) ? sr :
5973	>	reducer.apply(tr, sr));
5974	>	s = t.rights = s.nextRight;
5975	>	}
5976	>	}
5977	>	}
5978	>	}
5979	>	}
5980	>
5981	>	@SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5982	>	extends Traverser<K,V,V> {
5983	>	final BiFun<? super V, ? super V, ? extends V> reducer;
5984	>	V result;
5985	>	ReduceValuesTask<K,V> rights, nextRight;
5986	>	ReduceValuesTask
5987	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5988	>	ReduceValuesTask<K,V> nextRight,
5989	>	BiFun<? super V, ? super V, ? extends V> reducer) {
5990	>	super(m, p, b); this.nextRight = nextRight;
5991	>	this.reducer = reducer;
5992	>	}
5993	>	public final V getRawResult() { return result; }
5994	>	@SuppressWarnings("unchecked") public final void compute() {
5995	>	final BiFun<? super V, ? super V, ? extends V> reducer;
5996	>	if ((reducer = this.reducer) != null) {
5997	>	for (int b; (b = preSplit()) > 0;)
5998	>	(rights = new ReduceValuesTask<K,V>
5999	>	(map, this, b, rights, reducer)).fork();
6000	>	V r = null;
6001	>	V v;
6002	>	while ((v = advance()) != null) {
6003	>	V u = v;
6004	>	r = (r == null) ? u : reducer.apply(r, u);
6005	>	}
6006	>	result = r;
6007	>	CountedCompleter<?> c;
6008	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6009	>	ReduceValuesTask<K,V>
6010	>	t = (ReduceValuesTask<K,V>)c,
6011	>	s = t.rights;
6012	>	while (s != null) {
6013	>	V tr, sr;
6014	>	if ((sr = s.result) != null)
6015	>	t.result = (((tr = t.result) == null) ? sr :
6016	>	reducer.apply(tr, sr));
6017	>	s = t.rights = s.nextRight;
6018	>	}
6019	>	}
6020	>	}
6021	>	}
6022	>	}
6023	>
6024	>	@SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
6025	>	extends Traverser<K,V,Map.Entry<K,V>> {
6026	>	final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
6027	>	Map.Entry<K,V> result;
6028	>	ReduceEntriesTask<K,V> rights, nextRight;
6029	>	ReduceEntriesTask
6030	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6031	>	ReduceEntriesTask<K,V> nextRight,
6032	>	BiFun<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
6033	>	super(m, p, b); this.nextRight = nextRight;
6034	>	this.reducer = reducer;
6035	>	}
6036	>	public final Map.Entry<K,V> getRawResult() { return result; }
6037	>	@SuppressWarnings("unchecked") public final void compute() {
6038	>	final BiFun<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
6039	>	if ((reducer = this.reducer) != null) {
6040	>	for (int b; (b = preSplit()) > 0;)
6041	>	(rights = new ReduceEntriesTask<K,V>
6042	>	(map, this, b, rights, reducer)).fork();
6043	>	Map.Entry<K,V> r = null;
6044	>	V v;
6045	>	while ((v = advance()) != null) {
6046	>	Map.Entry<K,V> u = entryFor((K)nextKey, v);
6047	>	r = (r == null) ? u : reducer.apply(r, u);
6048	>	}
6049	>	result = r;
6050	>	CountedCompleter<?> c;
6051	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6052	>	ReduceEntriesTask<K,V>
6053	>	t = (ReduceEntriesTask<K,V>)c,
6054	>	s = t.rights;
6055	>	while (s != null) {
6056	>	Map.Entry<K,V> tr, sr;
6057	>	if ((sr = s.result) != null)
6058	>	t.result = (((tr = t.result) == null) ? sr :
6059	>	reducer.apply(tr, sr));
6060	>	s = t.rights = s.nextRight;
6061	>	}
6062	>	}
6063	>	}
6064	>	}
6065	>	}
6066	>
6067	>	@SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
6068	>	extends Traverser<K,V,U> {
6069	>	final Fun<? super K, ? extends U> transformer;
6070	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6071	>	U result;
6072	>	MapReduceKeysTask<K,V,U> rights, nextRight;
6073	>	MapReduceKeysTask
6074	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6075	>	MapReduceKeysTask<K,V,U> nextRight,
6076	>	Fun<? super K, ? extends U> transformer,
6077	>	BiFun<? super U, ? super U, ? extends U> reducer) {
6078	>	super(m, p, b); this.nextRight = nextRight;
6079	>	this.transformer = transformer;
6080	>	this.reducer = reducer;
6081	>	}
6082	>	public final U getRawResult() { return result; }
6083	>	@SuppressWarnings("unchecked") public final void compute() {
6084	>	final Fun<? super K, ? extends U> transformer;
6085	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6086	>	if ((transformer = this.transformer) != null &&
6087	>	(reducer = this.reducer) != null) {
6088	>	for (int b; (b = preSplit()) > 0;)
6089	>	(rights = new MapReduceKeysTask<K,V,U>
6090	>	(map, this, b, rights, transformer, reducer)).fork();
6091	>	U r = null, u;
6092	>	while (advance() != null) {
6093	>	if ((u = transformer.apply((K)nextKey)) != null)
6094	>	r = (r == null) ? u : reducer.apply(r, u);
6095	>	}
6096	>	result = r;
6097	>	CountedCompleter<?> c;
6098	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6099	>	MapReduceKeysTask<K,V,U>
6100	>	t = (MapReduceKeysTask<K,V,U>)c,
6101	>	s = t.rights;
6102	>	while (s != null) {
6103	>	U tr, sr;
6104	>	if ((sr = s.result) != null)
6105	>	t.result = (((tr = t.result) == null) ? sr :
6106	>	reducer.apply(tr, sr));
6107	>	s = t.rights = s.nextRight;
6108	>	}
6109	>	}
6110	>	}
6111	>	}
6112	>	}
6113	>
6114	>	@SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
6115	>	extends Traverser<K,V,U> {
6116	>	final Fun<? super V, ? extends U> transformer;
6117	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6118	>	U result;
6119	>	MapReduceValuesTask<K,V,U> rights, nextRight;
6120	>	MapReduceValuesTask
6121	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6122	>	MapReduceValuesTask<K,V,U> nextRight,
6123	>	Fun<? super V, ? extends U> transformer,
6124	>	BiFun<? super U, ? super U, ? extends U> reducer) {
6125	>	super(m, p, b); this.nextRight = nextRight;
6126	>	this.transformer = transformer;
6127	>	this.reducer = reducer;
6128	>	}
6129	>	public final U getRawResult() { return result; }
6130	>	@SuppressWarnings("unchecked") public final void compute() {
6131	>	final Fun<? super V, ? extends U> transformer;
6132	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6133	>	if ((transformer = this.transformer) != null &&
6134	>	(reducer = this.reducer) != null) {
6135	>	for (int b; (b = preSplit()) > 0;)
6136	>	(rights = new MapReduceValuesTask<K,V,U>
6137	>	(map, this, b, rights, transformer, reducer)).fork();
6138	>	U r = null, u;
6139	>	V v;
6140	>	while ((v = advance()) != null) {
6141	>	if ((u = transformer.apply(v)) != null)
6142	>	r = (r == null) ? u : reducer.apply(r, u);
6143	>	}
6144	>	result = r;
6145	>	CountedCompleter<?> c;
6146	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6147	>	MapReduceValuesTask<K,V,U>
6148	>	t = (MapReduceValuesTask<K,V,U>)c,
6149	>	s = t.rights;
6150	>	while (s != null) {
6151	>	U tr, sr;
6152	>	if ((sr = s.result) != null)
6153	>	t.result = (((tr = t.result) == null) ? sr :
6154	>	reducer.apply(tr, sr));
6155	>	s = t.rights = s.nextRight;
6156	>	}
6157	>	}
6158	>	}
6159	>	}
6160	>	}
6161	>
6162	>	@SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
6163	>	extends Traverser<K,V,U> {
6164	>	final Fun<Map.Entry<K,V>, ? extends U> transformer;
6165	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6166	>	U result;
6167	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
6168	>	MapReduceEntriesTask
6169	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6170	>	MapReduceEntriesTask<K,V,U> nextRight,
6171	>	Fun<Map.Entry<K,V>, ? extends U> transformer,
6172	>	BiFun<? super U, ? super U, ? extends U> reducer) {
6173	>	super(m, p, b); this.nextRight = nextRight;
6174	>	this.transformer = transformer;
6175	>	this.reducer = reducer;
6176	>	}
6177	>	public final U getRawResult() { return result; }
6178	>	@SuppressWarnings("unchecked") public final void compute() {
6179	>	final Fun<Map.Entry<K,V>, ? extends U> transformer;
6180	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6181	>	if ((transformer = this.transformer) != null &&
6182	>	(reducer = this.reducer) != null) {
6183	>	for (int b; (b = preSplit()) > 0;)
6184	>	(rights = new MapReduceEntriesTask<K,V,U>
6185	>	(map, this, b, rights, transformer, reducer)).fork();
6186	>	U r = null, u;
6187	>	V v;
6188	>	while ((v = advance()) != null) {
6189	>	if ((u = transformer.apply(entryFor((K)nextKey,
6190	>	v))) != null)
6191	>	r = (r == null) ? u : reducer.apply(r, u);
6192	>	}
6193	>	result = r;
6194	>	CountedCompleter<?> c;
6195	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6196	>	MapReduceEntriesTask<K,V,U>
6197	>	t = (MapReduceEntriesTask<K,V,U>)c,
6198	>	s = t.rights;
6199	>	while (s != null) {
6200	>	U tr, sr;
6201	>	if ((sr = s.result) != null)
6202	>	t.result = (((tr = t.result) == null) ? sr :
6203	>	reducer.apply(tr, sr));
6204	>	s = t.rights = s.nextRight;
6205	>	}
6206	>	}
6207	>	}
6208	>	}
6209	>	}
6210	>
6211	>	@SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
6212	>	extends Traverser<K,V,U> {
6213	>	final BiFun<? super K, ? super V, ? extends U> transformer;
6214	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6215	>	U result;
6216	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
6217	>	MapReduceMappingsTask
6218	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6219	>	MapReduceMappingsTask<K,V,U> nextRight,
6220	>	BiFun<? super K, ? super V, ? extends U> transformer,
6221	>	BiFun<? super U, ? super U, ? extends U> reducer) {
6222	>	super(m, p, b); this.nextRight = nextRight;
6223	>	this.transformer = transformer;
6224	>	this.reducer = reducer;
6225	>	}
6226	>	public final U getRawResult() { return result; }
6227	>	@SuppressWarnings("unchecked") public final void compute() {
6228	>	final BiFun<? super K, ? super V, ? extends U> transformer;
6229	>	final BiFun<? super U, ? super U, ? extends U> reducer;
6230	>	if ((transformer = this.transformer) != null &&
6231	>	(reducer = this.reducer) != null) {
6232	>	for (int b; (b = preSplit()) > 0;)
6233	>	(rights = new MapReduceMappingsTask<K,V,U>
6234	>	(map, this, b, rights, transformer, reducer)).fork();
6235	>	U r = null, u;
6236	>	V v;
6237	>	while ((v = advance()) != null) {
6238	>	if ((u = transformer.apply((K)nextKey, v)) != null)
6239	>	r = (r == null) ? u : reducer.apply(r, u);
6240	>	}
6241	>	result = r;
6242	>	CountedCompleter<?> c;
6243	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6244	>	MapReduceMappingsTask<K,V,U>
6245	>	t = (MapReduceMappingsTask<K,V,U>)c,
6246	>	s = t.rights;
6247	>	while (s != null) {
6248	>	U tr, sr;
6249	>	if ((sr = s.result) != null)
6250	>	t.result = (((tr = t.result) == null) ? sr :
6251	>	reducer.apply(tr, sr));
6252	>	s = t.rights = s.nextRight;
6253	>	}
6254	>	}
6255	>	}
6256	>	}
6257	>	}
6258	>
6259	>	@SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
6260	>	extends Traverser<K,V,Double> {
6261	>	final ObjectToDouble<? super K> transformer;
6262	>	final DoubleByDoubleToDouble reducer;
6263	>	final double basis;
6264	>	double result;
6265	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
6266	>	MapReduceKeysToDoubleTask
6267	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6268	>	MapReduceKeysToDoubleTask<K,V> nextRight,
6269	>	ObjectToDouble<? super K> transformer,
6270	>	double basis,
6271	>	DoubleByDoubleToDouble reducer) {
6272	>	super(m, p, b); this.nextRight = nextRight;
6273	>	this.transformer = transformer;
6274	>	this.basis = basis; this.reducer = reducer;
6275	>	}
6276	>	public final Double getRawResult() { return result; }
6277	>	@SuppressWarnings("unchecked") public final void compute() {
6278	>	final ObjectToDouble<? super K> transformer;
6279	>	final DoubleByDoubleToDouble reducer;
6280	>	if ((transformer = this.transformer) != null &&
6281	>	(reducer = this.reducer) != null) {
6282	>	double r = this.basis;
6283	>	for (int b; (b = preSplit()) > 0;)
6284	>	(rights = new MapReduceKeysToDoubleTask<K,V>
6285	>	(map, this, b, rights, transformer, r, reducer)).fork();
6286	>	while (advance() != null)
6287	>	r = reducer.apply(r, transformer.apply((K)nextKey));
6288	>	result = r;
6289	>	CountedCompleter<?> c;
6290	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6291	>	MapReduceKeysToDoubleTask<K,V>
6292	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
6293	>	s = t.rights;
6294	>	while (s != null) {
6295	>	t.result = reducer.apply(t.result, s.result);
6296	>	s = t.rights = s.nextRight;
6297	>	}
6298	>	}
6299	>	}
6300	>	}
6301	>	}
6302	>
6303	>	@SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
6304	>	extends Traverser<K,V,Double> {
6305	>	final ObjectToDouble<? super V> transformer;
6306	>	final DoubleByDoubleToDouble reducer;
6307	>	final double basis;
6308	>	double result;
6309	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
6310	>	MapReduceValuesToDoubleTask
6311	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6312	>	MapReduceValuesToDoubleTask<K,V> nextRight,
6313	>	ObjectToDouble<? super V> transformer,
6314	>	double basis,
6315	>	DoubleByDoubleToDouble reducer) {
6316	>	super(m, p, b); this.nextRight = nextRight;
6317	>	this.transformer = transformer;
6318	>	this.basis = basis; this.reducer = reducer;
6319	>	}
6320	>	public final Double getRawResult() { return result; }
6321	>	@SuppressWarnings("unchecked") public final void compute() {
6322	>	final ObjectToDouble<? super V> transformer;
6323	>	final DoubleByDoubleToDouble reducer;
6324	>	if ((transformer = this.transformer) != null &&
6325	>	(reducer = this.reducer) != null) {
6326	>	double r = this.basis;
6327	>	for (int b; (b = preSplit()) > 0;)
6328	>	(rights = new MapReduceValuesToDoubleTask<K,V>
6329	>	(map, this, b, rights, transformer, r, reducer)).fork();
6330	>	V v;
6331	>	while ((v = advance()) != null)
6332	>	r = reducer.apply(r, transformer.apply(v));
6333	>	result = r;
6334	>	CountedCompleter<?> c;
6335	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6336	>	MapReduceValuesToDoubleTask<K,V>
6337	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
6338	>	s = t.rights;
6339	>	while (s != null) {
6340	>	t.result = reducer.apply(t.result, s.result);
6341	>	s = t.rights = s.nextRight;
6342	>	}
6343	>	}
6344	>	}
6345	>	}
6346	>	}
6347	>
6348	>	@SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6349	>	extends Traverser<K,V,Double> {
6350	>	final ObjectToDouble<Map.Entry<K,V>> transformer;
6351	>	final DoubleByDoubleToDouble reducer;
6352	>	final double basis;
6353	>	double result;
6354	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6355	>	MapReduceEntriesToDoubleTask
6356	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6357	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
6358	>	ObjectToDouble<Map.Entry<K,V>> transformer,
6359	>	double basis,
6360	>	DoubleByDoubleToDouble reducer) {
6361	>	super(m, p, b); this.nextRight = nextRight;
6362	>	this.transformer = transformer;
6363	>	this.basis = basis; this.reducer = reducer;
6364	>	}
6365	>	public final Double getRawResult() { return result; }
6366	>	@SuppressWarnings("unchecked") public final void compute() {
6367	>	final ObjectToDouble<Map.Entry<K,V>> transformer;
6368	>	final DoubleByDoubleToDouble reducer;
6369	>	if ((transformer = this.transformer) != null &&
6370	>	(reducer = this.reducer) != null) {
6371	>	double r = this.basis;
6372	>	for (int b; (b = preSplit()) > 0;)
6373	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
6374	>	(map, this, b, rights, transformer, r, reducer)).fork();
6375	>	V v;
6376	>	while ((v = advance()) != null)
6377	>	r = reducer.apply(r, transformer.apply(entryFor((K)nextKey,
6378	>	v)));
6379	>	result = r;
6380	>	CountedCompleter<?> c;
6381	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6382	>	MapReduceEntriesToDoubleTask<K,V>
6383	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
6384	>	s = t.rights;
6385	>	while (s != null) {
6386	>	t.result = reducer.apply(t.result, s.result);
6387	>	s = t.rights = s.nextRight;
6388	>	}
6389	>	}
6390	>	}
6391	>	}
6392	>	}
6393	>
6394	>	@SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6395	>	extends Traverser<K,V,Double> {
6396	>	final ObjectByObjectToDouble<? super K, ? super V> transformer;
6397	>	final DoubleByDoubleToDouble reducer;
6398	>	final double basis;
6399	>	double result;
6400	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6401	>	MapReduceMappingsToDoubleTask
6402	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6403	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
6404	>	ObjectByObjectToDouble<? super K, ? super V> transformer,
6405	>	double basis,
6406	>	DoubleByDoubleToDouble reducer) {
6407	>	super(m, p, b); this.nextRight = nextRight;
6408	>	this.transformer = transformer;
6409	>	this.basis = basis; this.reducer = reducer;
6410	>	}
6411	>	public final Double getRawResult() { return result; }
6412	>	@SuppressWarnings("unchecked") public final void compute() {
6413	>	final ObjectByObjectToDouble<? super K, ? super V> transformer;
6414	>	final DoubleByDoubleToDouble reducer;
6415	>	if ((transformer = this.transformer) != null &&
6416	>	(reducer = this.reducer) != null) {
6417	>	double r = this.basis;
6418	>	for (int b; (b = preSplit()) > 0;)
6419	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
6420	>	(map, this, b, rights, transformer, r, reducer)).fork();
6421	>	V v;
6422	>	while ((v = advance()) != null)
6423	>	r = reducer.apply(r, transformer.apply((K)nextKey, v));
6424	>	result = r;
6425	>	CountedCompleter<?> c;
6426	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6427	>	MapReduceMappingsToDoubleTask<K,V>
6428	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
6429	>	s = t.rights;
6430	>	while (s != null) {
6431	>	t.result = reducer.apply(t.result, s.result);
6432	>	s = t.rights = s.nextRight;
6433	>	}
6434	>	}
6435	>	}
6436	>	}
6437	>	}
6438	>
6439	>	@SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6440	>	extends Traverser<K,V,Long> {
6441	>	final ObjectToLong<? super K> transformer;
6442	>	final LongByLongToLong reducer;
6443	>	final long basis;
6444	>	long result;
6445	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
6446	>	MapReduceKeysToLongTask
6447	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6448	>	MapReduceKeysToLongTask<K,V> nextRight,
6449	>	ObjectToLong<? super K> transformer,
6450	>	long basis,
6451	>	LongByLongToLong reducer) {
6452	>	super(m, p, b); this.nextRight = nextRight;
6453	>	this.transformer = transformer;
6454	>	this.basis = basis; this.reducer = reducer;
6455	>	}
6456	>	public final Long getRawResult() { return result; }
6457	>	@SuppressWarnings("unchecked") public final void compute() {
6458	>	final ObjectToLong<? super K> transformer;
6459	>	final LongByLongToLong reducer;
6460	>	if ((transformer = this.transformer) != null &&
6461	>	(reducer = this.reducer) != null) {
6462	>	long r = this.basis;
6463	>	for (int b; (b = preSplit()) > 0;)
6464	>	(rights = new MapReduceKeysToLongTask<K,V>
6465	>	(map, this, b, rights, transformer, r, reducer)).fork();
6466	>	while (advance() != null)
6467	>	r = reducer.apply(r, transformer.apply((K)nextKey));
6468	>	result = r;
6469	>	CountedCompleter<?> c;
6470	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6471	>	MapReduceKeysToLongTask<K,V>
6472	>	t = (MapReduceKeysToLongTask<K,V>)c,
6473	>	s = t.rights;
6474	>	while (s != null) {
6475	>	t.result = reducer.apply(t.result, s.result);
6476	>	s = t.rights = s.nextRight;
6477	>	}
6478	>	}
6479	>	}
6480	>	}
6481	>	}
6482	>
6483	>	@SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6484	>	extends Traverser<K,V,Long> {
6485	>	final ObjectToLong<? super V> transformer;
6486	>	final LongByLongToLong reducer;
6487	>	final long basis;
6488	>	long result;
6489	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
6490	>	MapReduceValuesToLongTask
6491	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6492	>	MapReduceValuesToLongTask<K,V> nextRight,
6493	>	ObjectToLong<? super V> transformer,
6494	>	long basis,
6495	>	LongByLongToLong reducer) {
6496	>	super(m, p, b); this.nextRight = nextRight;
6497	>	this.transformer = transformer;
6498	>	this.basis = basis; this.reducer = reducer;
6499	>	}
6500	>	public final Long getRawResult() { return result; }
6501	>	@SuppressWarnings("unchecked") public final void compute() {
6502	>	final ObjectToLong<? super V> transformer;
6503	>	final LongByLongToLong reducer;
6504	>	if ((transformer = this.transformer) != null &&
6505	>	(reducer = this.reducer) != null) {
6506	>	long r = this.basis;
6507	>	for (int b; (b = preSplit()) > 0;)
6508	>	(rights = new MapReduceValuesToLongTask<K,V>
6509	>	(map, this, b, rights, transformer, r, reducer)).fork();
6510	>	V v;
6511	>	while ((v = advance()) != null)
6512	>	r = reducer.apply(r, transformer.apply(v));
6513	>	result = r;
6514	>	CountedCompleter<?> c;
6515	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6516	>	MapReduceValuesToLongTask<K,V>
6517	>	t = (MapReduceValuesToLongTask<K,V>)c,
6518	>	s = t.rights;
6519	>	while (s != null) {
6520	>	t.result = reducer.apply(t.result, s.result);
6521	>	s = t.rights = s.nextRight;
6522	>	}
6523	>	}
6524	>	}
6525	>	}
6526	>	}
6527	>
6528	>	@SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6529	>	extends Traverser<K,V,Long> {
6530	>	final ObjectToLong<Map.Entry<K,V>> transformer;
6531	>	final LongByLongToLong reducer;
6532	>	final long basis;
6533	>	long result;
6534	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6535	>	MapReduceEntriesToLongTask
6536	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6537	>	MapReduceEntriesToLongTask<K,V> nextRight,
6538	>	ObjectToLong<Map.Entry<K,V>> transformer,
6539	>	long basis,
6540	>	LongByLongToLong reducer) {
6541	>	super(m, p, b); this.nextRight = nextRight;
6542	>	this.transformer = transformer;
6543	>	this.basis = basis; this.reducer = reducer;
6544	>	}
6545	>	public final Long getRawResult() { return result; }
6546	>	@SuppressWarnings("unchecked") public final void compute() {
6547	>	final ObjectToLong<Map.Entry<K,V>> transformer;
6548	>	final LongByLongToLong reducer;
6549	>	if ((transformer = this.transformer) != null &&
6550	>	(reducer = this.reducer) != null) {
6551	>	long r = this.basis;
6552	>	for (int b; (b = preSplit()) > 0;)
6553	>	(rights = new MapReduceEntriesToLongTask<K,V>
6554	>	(map, this, b, rights, transformer, r, reducer)).fork();
6555	>	V v;
6556	>	while ((v = advance()) != null)
6557	>	r = reducer.apply(r, transformer.apply(entryFor((K)nextKey,
6558	>	v)));
6559	>	result = r;
6560	>	CountedCompleter<?> c;
6561	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6562	>	MapReduceEntriesToLongTask<K,V>
6563	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6564	>	s = t.rights;
6565	>	while (s != null) {
6566	>	t.result = reducer.apply(t.result, s.result);
6567	>	s = t.rights = s.nextRight;
6568	>	}
6569	>	}
6570	>	}
6571	>	}
6572	>	}
6573	>
6574	>	@SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6575	>	extends Traverser<K,V,Long> {
6576	>	final ObjectByObjectToLong<? super K, ? super V> transformer;
6577	>	final LongByLongToLong reducer;
6578	>	final long basis;
6579	>	long result;
6580	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6581	>	MapReduceMappingsToLongTask
6582	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6583	>	MapReduceMappingsToLongTask<K,V> nextRight,
6584	>	ObjectByObjectToLong<? super K, ? super V> transformer,
6585	>	long basis,
6586	>	LongByLongToLong reducer) {
6587	>	super(m, p, b); this.nextRight = nextRight;
6588	>	this.transformer = transformer;
6589	>	this.basis = basis; this.reducer = reducer;
6590	>	}
6591	>	public final Long getRawResult() { return result; }
6592	>	@SuppressWarnings("unchecked") public final void compute() {
6593	>	final ObjectByObjectToLong<? super K, ? super V> transformer;
6594	>	final LongByLongToLong reducer;
6595	>	if ((transformer = this.transformer) != null &&
6596	>	(reducer = this.reducer) != null) {
6597	>	long r = this.basis;
6598	>	for (int b; (b = preSplit()) > 0;)
6599	>	(rights = new MapReduceMappingsToLongTask<K,V>
6600	>	(map, this, b, rights, transformer, r, reducer)).fork();
6601	>	V v;
6602	>	while ((v = advance()) != null)
6603	>	r = reducer.apply(r, transformer.apply((K)nextKey, v));
6604	>	result = r;
6605	>	CountedCompleter<?> c;
6606	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6607	>	MapReduceMappingsToLongTask<K,V>
6608	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6609	>	s = t.rights;
6610	>	while (s != null) {
6611	>	t.result = reducer.apply(t.result, s.result);
6612	>	s = t.rights = s.nextRight;
6613	>	}
6614	>	}
6615	>	}
6616	>	}
6617	>	}
6618	>
6619	>	@SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6620	>	extends Traverser<K,V,Integer> {
6621	>	final ObjectToInt<? super K> transformer;
6622	>	final IntByIntToInt reducer;
6623	>	final int basis;
6624	>	int result;
6625	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6626	>	MapReduceKeysToIntTask
6627	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6628	>	MapReduceKeysToIntTask<K,V> nextRight,
6629	>	ObjectToInt<? super K> transformer,
6630	>	int basis,
6631	>	IntByIntToInt reducer) {
6632	>	super(m, p, b); this.nextRight = nextRight;
6633	>	this.transformer = transformer;
6634	>	this.basis = basis; this.reducer = reducer;
6635	>	}
6636	>	public final Integer getRawResult() { return result; }
6637	>	@SuppressWarnings("unchecked") public final void compute() {
6638	>	final ObjectToInt<? super K> transformer;
6639	>	final IntByIntToInt reducer;
6640	>	if ((transformer = this.transformer) != null &&
6641	>	(reducer = this.reducer) != null) {
6642	>	int r = this.basis;
6643	>	for (int b; (b = preSplit()) > 0;)
6644	>	(rights = new MapReduceKeysToIntTask<K,V>
6645	>	(map, this, b, rights, transformer, r, reducer)).fork();
6646	>	while (advance() != null)
6647	>	r = reducer.apply(r, transformer.apply((K)nextKey));
6648	>	result = r;
6649	>	CountedCompleter<?> c;
6650	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6651	>	MapReduceKeysToIntTask<K,V>
6652	>	t = (MapReduceKeysToIntTask<K,V>)c,
6653	>	s = t.rights;
6654	>	while (s != null) {
6655	>	t.result = reducer.apply(t.result, s.result);
6656	>	s = t.rights = s.nextRight;
6657	>	}
6658	>	}
6659	>	}
6660	>	}
6661	>	}
6662	>
6663	>	@SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6664	>	extends Traverser<K,V,Integer> {
6665	>	final ObjectToInt<? super V> transformer;
6666	>	final IntByIntToInt reducer;
6667	>	final int basis;
6668	>	int result;
6669	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6670	>	MapReduceValuesToIntTask
6671	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6672	>	MapReduceValuesToIntTask<K,V> nextRight,
6673	>	ObjectToInt<? super V> transformer,
6674	>	int basis,
6675	>	IntByIntToInt reducer) {
6676	>	super(m, p, b); this.nextRight = nextRight;
6677	>	this.transformer = transformer;
6678	>	this.basis = basis; this.reducer = reducer;
6679	>	}
6680	>	public final Integer getRawResult() { return result; }
6681	>	@SuppressWarnings("unchecked") public final void compute() {
6682	>	final ObjectToInt<? super V> transformer;
6683	>	final IntByIntToInt reducer;
6684	>	if ((transformer = this.transformer) != null &&
6685	>	(reducer = this.reducer) != null) {
6686	>	int r = this.basis;
6687	>	for (int b; (b = preSplit()) > 0;)
6688	>	(rights = new MapReduceValuesToIntTask<K,V>
6689	>	(map, this, b, rights, transformer, r, reducer)).fork();
6690	>	V v;
6691	>	while ((v = advance()) != null)
6692	>	r = reducer.apply(r, transformer.apply(v));
6693	>	result = r;
6694	>	CountedCompleter<?> c;
6695	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6696	>	MapReduceValuesToIntTask<K,V>
6697	>	t = (MapReduceValuesToIntTask<K,V>)c,
6698	>	s = t.rights;
6699	>	while (s != null) {
6700	>	t.result = reducer.apply(t.result, s.result);
6701	>	s = t.rights = s.nextRight;
6702	>	}
6703	>	}
6704	>	}
6705	>	}
6706	>	}
6707	>
6708	>	@SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6709	>	extends Traverser<K,V,Integer> {
6710	>	final ObjectToInt<Map.Entry<K,V>> transformer;
6711	>	final IntByIntToInt reducer;
6712	>	final int basis;
6713	>	int result;
6714	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6715	>	MapReduceEntriesToIntTask
6716	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6717	>	MapReduceEntriesToIntTask<K,V> nextRight,
6718	>	ObjectToInt<Map.Entry<K,V>> transformer,
6719	>	int basis,
6720	>	IntByIntToInt reducer) {
6721	>	super(m, p, b); this.nextRight = nextRight;
6722	>	this.transformer = transformer;
6723	>	this.basis = basis; this.reducer = reducer;
6724	>	}
6725	>	public final Integer getRawResult() { return result; }
6726	>	@SuppressWarnings("unchecked") public final void compute() {
6727	>	final ObjectToInt<Map.Entry<K,V>> transformer;
6728	>	final IntByIntToInt reducer;
6729	>	if ((transformer = this.transformer) != null &&
6730	>	(reducer = this.reducer) != null) {
6731	>	int r = this.basis;
6732	>	for (int b; (b = preSplit()) > 0;)
6733	>	(rights = new MapReduceEntriesToIntTask<K,V>
6734	>	(map, this, b, rights, transformer, r, reducer)).fork();
6735	>	V v;
6736	>	while ((v = advance()) != null)
6737	>	r = reducer.apply(r, transformer.apply(entryFor((K)nextKey,
6738	>	v)));
6739	>	result = r;
6740	>	CountedCompleter<?> c;
6741	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6742	>	MapReduceEntriesToIntTask<K,V>
6743	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6744	>	s = t.rights;
6745	>	while (s != null) {
6746	>	t.result = reducer.apply(t.result, s.result);
6747	>	s = t.rights = s.nextRight;
6748	>	}
6749	>	}
6750	>	}
6751	>	}
6752	>	}
6753	>
6754	>	@SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6755	>	extends Traverser<K,V,Integer> {
6756	>	final ObjectByObjectToInt<? super K, ? super V> transformer;
6757	>	final IntByIntToInt reducer;
6758	>	final int basis;
6759	>	int result;
6760	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6761	>	MapReduceMappingsToIntTask
6762	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6763	>	MapReduceMappingsToIntTask<K,V> nextRight,
6764	>	ObjectByObjectToInt<? super K, ? super V> transformer,
6765	>	int basis,
6766	>	IntByIntToInt reducer) {
6767	>	super(m, p, b); this.nextRight = nextRight;
6768	>	this.transformer = transformer;
6769	>	this.basis = basis; this.reducer = reducer;
6770	>	}
6771	>	public final Integer getRawResult() { return result; }
6772	>	@SuppressWarnings("unchecked") public final void compute() {
6773	>	final ObjectByObjectToInt<? super K, ? super V> transformer;
6774	>	final IntByIntToInt reducer;
6775	>	if ((transformer = this.transformer) != null &&
6776	>	(reducer = this.reducer) != null) {
6777	>	int r = this.basis;
6778	>	for (int b; (b = preSplit()) > 0;)
6779	>	(rights = new MapReduceMappingsToIntTask<K,V>
6780	>	(map, this, b, rights, transformer, r, reducer)).fork();
6781	>	V v;
6782	>	while ((v = advance()) != null)
6783	>	r = reducer.apply(r, transformer.apply((K)nextKey, v));
6784	>	result = r;
6785	>	CountedCompleter<?> c;
6786	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6787	>	MapReduceMappingsToIntTask<K,V>
6788	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6789	>	s = t.rights;
6790	>	while (s != null) {
6791	>	t.result = reducer.apply(t.result, s.result);
6792	>	s = t.rights = s.nextRight;
6793	>	}
6794	>	}
6795	>	}
6796		}
6797		}
6798
6799		// Unsafe mechanics
6800	<	private static final sun.misc.Unsafe UNSAFE;
6801	<	private static final long SBASE;
6802	<	private static final int SSHIFT;
6803	<	private static final long TBASE;
6804	<	private static final int TSHIFT;
6800	>	private static final sun.misc.Unsafe U;
6801	>	private static final long SIZECTL;
6802	>	private static final long TRANSFERINDEX;
6803	>	private static final long TRANSFERORIGIN;
6804	>	private static final long BASECOUNT;
6805	>	private static final long COUNTERBUSY;
6806	>	private static final long CELLVALUE;
6807	>	private static final long ABASE;
6808	>	private static final int ASHIFT;
6809
6810		static {
6811	<	int ss, ts;
6811	>	int ss;
6812		try {
6813	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
6814	<	Class tc = HashEntry[].class;
6815	<	Class sc = Segment[].class;
6816	<	TBASE = UNSAFE.arrayBaseOffset(tc);
6817	<	SBASE = UNSAFE.arrayBaseOffset(sc);
6818	<	ts = UNSAFE.arrayIndexScale(tc);
6819	<	ss = UNSAFE.arrayIndexScale(sc);
6813	>	U = sun.misc.Unsafe.getUnsafe();
6814	>	Class<?> k = ConcurrentHashMap.class;
6815	>	SIZECTL = U.objectFieldOffset
6816	>	(k.getDeclaredField("sizeCtl"));
6817	>	TRANSFERINDEX = U.objectFieldOffset
6818	>	(k.getDeclaredField("transferIndex"));
6819	>	TRANSFERORIGIN = U.objectFieldOffset
6820	>	(k.getDeclaredField("transferOrigin"));
6821	>	BASECOUNT = U.objectFieldOffset
6822	>	(k.getDeclaredField("baseCount"));
6823	>	COUNTERBUSY = U.objectFieldOffset
6824	>	(k.getDeclaredField("counterBusy"));
6825	>	Class<?> ck = CounterCell.class;
6826	>	CELLVALUE = U.objectFieldOffset
6827	>	(ck.getDeclaredField("value"));
6828	>	Class<?> sc = Node[].class;
6829	>	ABASE = U.arrayBaseOffset(sc);
6830	>	ss = U.arrayIndexScale(sc);
6831	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(ss);
6832		} catch (Exception e) {
6833		throw new Error(e);
6834		}
6835	<	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
6835	>	if ((ss & (ss-1)) != 0)
6836		throw new Error("data type scale not a power of two");
1488	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1489	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
6837		}
6838
6839		}

Diff Legend

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