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Revision 1.24 by dl, Fri Oct 10 23:51:28 2003 UTC vs.
Revision 1.170 by jsr166, Mon Jan 28 17:27:03 2013 UTC

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1		/*
2		* Written by Doug Lea with assistance from members of JCP JSR-166
3	<	* Expert Group and released to the public domain. Use, modify, and
4	<	* redistribute this code in any way without acknowledgement.
3	>	* Expert Group and released to the public domain, as explained at
4	>	* http://creativecommons.org/publicdomain/zero/1.0/
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	>	import java.util.function.*;
11	>	import java.util.Spliterator;
12	>	import java.util.stream.Stream;
13	>	import java.util.stream.Streams;
14	>
15	>	import java.util.Comparator;
16	>	import java.util.Arrays;
17	>	import java.util.Map;
18	>	import java.util.Set;
19	>	import java.util.Collection;
20	>	import java.util.AbstractMap;
21	>	import java.util.AbstractSet;
22	>	import java.util.AbstractCollection;
23	>	import java.util.Hashtable;
24	>	import java.util.HashMap;
25	>	import java.util.Iterator;
26	>	import java.util.Enumeration;
27	>	import java.util.ConcurrentModificationException;
28	>	import java.util.NoSuchElementException;
29	>	import java.util.concurrent.ConcurrentMap;
30	>	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
31	>	import java.util.concurrent.atomic.AtomicInteger;
32	>	import java.util.concurrent.atomic.AtomicReference;
33		import java.io.Serializable;
11	–	import java.io.IOException;
12	–	import java.io.ObjectInputStream;
13	–	import java.io.ObjectOutputStream;
34
35		/**
36		* A hash table supporting full concurrency of retrievals and
37	<	* adjustable expected concurrency for updates. This class obeys the
37	>	* high expected concurrency for updates. This class obeys the
38		* same functional specification as {@link java.util.Hashtable}, and
39		* includes versions of methods corresponding to each method of
40	<	* <tt>Hashtable</tt> . However, even though all operations are
40	>	* {@code Hashtable}. However, even though all operations are
41		* thread-safe, retrieval operations do <em>not</em> entail locking,
42		* and there is <em>not</em> any support for locking the entire table
43		* in a way that prevents all access.  This class is fully
44	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
44	>	* interoperable with {@code Hashtable} in programs that rely on its
45		* thread safety but not on its synchronization details.
46		*
47	<	* <p> Retrieval operations (including <tt>get</tt>) ordinarily
48	<	* overlap with update operations (including <tt>put</tt> and
49	<	* <tt>remove</tt>). Retrievals reflect the results of the most
47	>	* <p>Retrieval operations (including {@code get}) generally do not
48	>	* block, so may overlap with update operations (including {@code put}
49	>	* and {@code remove}). Retrievals reflect the results of the most
50		* recently <em>completed</em> update operations holding upon their
51	<	* onset.  For aggregate operations such as <tt>putAll</tt> and
52	<	* <tt>clear</tt>, concurrent retrievals may reflect insertion or
53	<	* removal of only some entries.  Similarly, Iterators and
54	<	* Enumerations return elements reflecting the state of the hash table
55	<	* at some point at or since the creation of the iterator/enumeration.
56	<	* They do <em>not</em> throw <tt>ConcurrentModificationException</tt>.
57	<	* However, Iterators are designed to be used by only one thread at a
58	<	* time.
59	<	*
60	<	* <p> The allowed concurrency among update operations is guided by
61	<	* the optional <tt>concurrencyLevel</tt> constructor argument
62	<	* (default 16), which is used as a hint for internal sizing.  The
63	<	* table is internally partitioned to try to permit the indicated
64	<	* number of concurrent updates without contention. Because placement
65	<	* in hash tables is essentially random, the actual concurrency will
66	<	* vary.  Ideally, you should choose a value to accommodate as many
67	<	* threads as will ever concurrently access the table. Using a
68	<	* significantly higher value than you need can waste space and time,
69	<	* and a significantly lower value can lead to thread contention. But
70	<	* overestimates and underestimates within an order of magnitude do
71	<	* not usually have much noticeable impact.
72	<	*
73	<	* <p>This class implements all of the <em>optional</em> methods
74	<	* of the {@link Map} and {@link Iterator} interfaces.
75	<	*
76	<	* <p> Like {@link java.util.Hashtable} but unlike {@link
77	<	* java.util.HashMap}, this class does NOT allow <tt>null</tt> to be
78	<	* used as a key or value.
51	>	* onset. (More formally, an update operation for a given key bears a
52	>	* <em>happens-before</em> relation with any (non-null) retrieval for
53	>	* that key reporting the updated value.)  For aggregate operations
54	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
55	>	* reflect insertion or removal of only some entries.  Similarly,
56	>	* Iterators and Enumerations return elements reflecting the state of
57	>	* the hash table at some point at or since the creation of the
58	>	* iterator/enumeration.  They do <em>not</em> throw {@link
59	>	* ConcurrentModificationException}.  However, iterators are designed
60	>	* to be used by only one thread at a time.  Bear in mind that the
61	>	* results of aggregate status methods including {@code size}, {@code
62	>	* isEmpty}, and {@code containsValue} are typically useful only when
63	>	* a map is not undergoing concurrent updates in other threads.
64	>	* Otherwise the results of these methods reflect transient states
65	>	* that may be adequate for monitoring or estimation purposes, but not
66	>	* for program control.
67	>	*
68	>	* <p>The table is dynamically expanded when there are too many
69	>	* collisions (i.e., keys that have distinct hash codes but fall into
70	>	* the same slot modulo the table size), with the expected average
71	>	* effect of maintaining roughly two bins per mapping (corresponding
72	>	* to a 0.75 load factor threshold for resizing). There may be much
73	>	* variance around this average as mappings are added and removed, but
74	>	* overall, this maintains a commonly accepted time/space tradeoff for
75	>	* hash tables.  However, resizing this or any other kind of hash
76	>	* table may be a relatively slow operation. When possible, it is a
77	>	* good idea to provide a size estimate as an optional {@code
78	>	* initialCapacity} constructor argument. An additional optional
79	>	* {@code loadFactor} constructor argument provides a further means of
80	>	* customizing initial table capacity by specifying the table density
81	>	* to be used in calculating the amount of space to allocate for the
82	>	* given number of elements.  Also, for compatibility with previous
83	>	* versions of this class, constructors may optionally specify an
84	>	* expected {@code concurrencyLevel} as an additional hint for
85	>	* internal sizing.  Note that using many keys with exactly the same
86	>	* {@code hashCode()} is a sure way to slow down performance of any
87	>	* hash table.
88	>	*
89	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
90	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
91	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
92	>	* mapped values are (perhaps transiently) not used or all take the
93	>	* same mapping value.
94	>	*
95	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
96	>	* form of histogram or multiset) by using {@link
97	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
98	>	* {@link #computeIfAbsent}. For example, to add a count to a {@code
99	>	* ConcurrentHashMap<String,LongAdder> freqs}, you can use {@code
100	>	* freqs.computeIfAbsent(k -> new LongAdder()).increment();}
101	>	*
102	>	* <p>This class and its views and iterators implement all of the
103	>	* <em>optional</em> methods of the {@link Map} and {@link Iterator}
104	>	* interfaces.
105	>	*
106	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
107	>	* does <em>not</em> allow {@code null} to be used as a key or value.
108	>	*
109	>	* <p>ConcurrentHashMaps support sequential and parallel operations
110	>	* bulk operations. (Parallel forms use the {@link
111	>	* ForkJoinPool#commonPool()}). Tasks that may be used in other
112	>	* contexts are available in class {@link ForkJoinTasks}. These
113	>	* operations are designed to be safely, and often sensibly, applied
114	>	* even with maps that are being concurrently updated by other
115	>	* threads; for example, when computing a snapshot summary of the
116	>	* values in a shared registry.  There are three kinds of operation,
117	>	* each with four forms, accepting functions with Keys, Values,
118	>	* Entries, and (Key, Value) arguments and/or return values. Because
119	>	* the elements of a ConcurrentHashMap are not ordered in any
120	>	* particular way, and may be processed in different orders in
121	>	* different parallel executions, the correctness of supplied
122	>	* functions should not depend on any ordering, or on any other
123	>	* objects or values that may transiently change while computation is
124	>	* in progress; and except for forEach actions, should ideally be
125	>	* side-effect-free.
126	>	*
127	>	* <ul>
128	>	* <li> forEach: Perform a given action on each element.
129	>	* A variant form applies a given transformation on each element
130	>	* before performing the action.</li>
131	>	*
132	>	* <li> search: Return the first available non-null result of
133	>	* applying a given function on each element; skipping further
134	>	* search when a result is found.</li>
135	>	*
136	>	* <li> reduce: Accumulate each element.  The supplied reduction
137	>	* function cannot rely on ordering (more formally, it should be
138	>	* both associative and commutative).  There are five variants:
139	>	*
140	>	* <ul>
141	>	*
142	>	* <li> Plain reductions. (There is not a form of this method for
143	>	* (key, value) function arguments since there is no corresponding
144	>	* return type.)</li>
145	>	*
146	>	* <li> Mapped reductions that accumulate the results of a given
147	>	* function applied to each element.</li>
148	>	*
149	>	* <li> Reductions to scalar doubles, longs, and ints, using a
150	>	* given basis value.</li>
151	>	*
152	>	* </li>
153	>	* </ul>
154	>	* </ul>
155	>	*
156	>	* <p>The concurrency properties of bulk operations follow
157	>	* from those of ConcurrentHashMap: Any non-null result returned
158	>	* from {@code get(key)} and related access methods bears a
159	>	* happens-before relation with the associated insertion or
160	>	* update.  The result of any bulk operation reflects the
161	>	* composition of these per-element relations (but is not
162	>	* necessarily atomic with respect to the map as a whole unless it
163	>	* is somehow known to be quiescent).  Conversely, because keys
164	>	* and values in the map are never null, null serves as a reliable
165	>	* atomic indicator of the current lack of any result.  To
166	>	* maintain this property, null serves as an implicit basis for
167	>	* all non-scalar reduction operations. For the double, long, and
168	>	* int versions, the basis should be one that, when combined with
169	>	* any other value, returns that other value (more formally, it
170	>	* should be the identity element for the reduction). Most common
171	>	* reductions have these properties; for example, computing a sum
172	>	* with basis 0 or a minimum with basis MAX_VALUE.
173	>	*
174	>	* <p>Search and transformation functions provided as arguments
175	>	* should similarly return null to indicate the lack of any result
176	>	* (in which case it is not used). In the case of mapped
177	>	* reductions, this also enables transformations to serve as
178	>	* filters, returning null (or, in the case of primitive
179	>	* specializations, the identity basis) if the element should not
180	>	* be combined. You can create compound transformations and
181	>	* filterings by composing them yourself under this "null means
182	>	* there is nothing there now" rule before using them in search or
183	>	* reduce operations.
184	>	*
185	>	* <p>Methods accepting and/or returning Entry arguments maintain
186	>	* key-value associations. They may be useful for example when
187	>	* finding the key for the greatest value. Note that "plain" Entry
188	>	* arguments can be supplied using {@code new
189	>	* AbstractMap.SimpleEntry(k,v)}.
190	>	*
191	>	* <p>Bulk operations may complete abruptly, throwing an
192	>	* exception encountered in the application of a supplied
193	>	* function. Bear in mind when handling such exceptions that other
194	>	* concurrently executing functions could also have thrown
195	>	* exceptions, or would have done so if the first exception had
196	>	* not occurred.
197	>	*
198	>	* <p>Speedups for parallel compared to sequential forms are common
199	>	* but not guaranteed.  Parallel operations involving brief functions
200	>	* on small maps may execute more slowly than sequential forms if the
201	>	* underlying work to parallelize the computation is more expensive
202	>	* than the computation itself.  Similarly, parallelization may not
203	>	* lead to much actual parallelism if all processors are busy
204	>	* performing unrelated tasks.
205	>	*
206	>	* <p>All arguments to all task methods must be non-null.
207	>	*
208	>	* <p>This class is a member of the
209	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
210	>	* Java Collections Framework</a>.
211		*
212		* @since 1.5
213		* @author Doug Lea
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>, Cloneable, Serializable {
217	>	public class ConcurrentHashMap<K, V>
218	>	implements ConcurrentMap<K, V>, Serializable {
219		private static final long serialVersionUID = 7249069246763182397L;
220
221		/*
222	<	* The basic strategy is to subdivide the table among Segments,
223	<	* each of which itself is a concurrently readable hash table.
222	>	* Overview:
223	>	*
224	>	* The primary design goal of this hash table is to maintain
225	>	* concurrent readability (typically method get(), but also
226	>	* iterators and related methods) while minimizing update
227	>	* contention. Secondary goals are to keep space consumption about
228	>	* the same or better than java.util.HashMap, and to support high
229	>	* initial insertion rates on an empty table by many threads.
230	>	*
231	>	* Each key-value mapping is held in a Node.  Because Node key
232	>	* fields can contain special values, they are defined using plain
233	>	* Object types (not type "K"). This leads to a lot of explicit
234	>	* casting (and many explicit warning suppressions to tell
235	>	* compilers not to complain about it). It also allows some of the
236	>	* public methods to be factored into a smaller number of internal
237	>	* methods (although sadly not so for the five variants of
238	>	* put-related operations). The validation-based approach
239	>	* explained below leads to a lot of code sprawl because
240	>	* retry-control precludes factoring into smaller methods.
241	>	*
242	>	* The table is lazily initialized to a power-of-two size upon the
243	>	* first insertion.  Each bin in the table normally contains a
244	>	* list of Nodes (most often, the list has only zero or one Node).
245	>	* Table accesses require volatile/atomic reads, writes, and
246	>	* CASes.  Because there is no other way to arrange this without
247	>	* adding further indirections, we use intrinsics
248	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
249	>	* are always accurately traversable under volatile reads, so long
250	>	* as lookups check hash code and non-nullness of value before
251	>	* checking key equality.
252	>	*
253	>	* We use the top (sign) bit of Node hash fields for control
254	>	* purposes -- it is available anyway because of addressing
255	>	* constraints.  Nodes with negative hash fields are forwarding
256	>	* nodes to either TreeBins or resized tables.  The lower 31 bits
257	>	* of each normal Node's hash field contain a transformation of
258	>	* the key's hash code.
259	>	*
260	>	* Insertion (via put or its variants) of the first node in an
261	>	* empty bin is performed by just CASing it to the bin.  This is
262	>	* by far the most common case for put operations under most
263	>	* key/hash distributions.  Other update operations (insert,
264	>	* delete, and replace) require locks.  We do not want to waste
265	>	* the space required to associate a distinct lock object with
266	>	* each bin, so instead use the first node of a bin list itself as
267	>	* a lock. Locking support for these locks relies on builtin
268	>	* "synchronized" monitors.
269	>	*
270	>	* Using the first node of a list as a lock does not by itself
271	>	* suffice though: When a node is locked, any update must first
272	>	* validate that it is still the first node after locking it, and
273	>	* retry if not. Because new nodes are always appended to lists,
274	>	* once a node is first in a bin, it remains first until deleted
275	>	* or the bin becomes invalidated (upon resizing).  However,
276	>	* operations that only conditionally update may inspect nodes
277	>	* until the point of update. This is a converse of sorts to the
278	>	* lazy locking technique described by Herlihy & Shavit.
279	>	*
280	>	* The main disadvantage of per-bin locks is that other update
281	>	* operations on other nodes in a bin list protected by the same
282	>	* lock can stall, for example when user equals() or mapping
283	>	* functions take a long time.  However, statistically, under
284	>	* random hash codes, this is not a common problem.  Ideally, the
285	>	* frequency of nodes in bins follows a Poisson distribution
286	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
287	>	* parameter of about 0.5 on average, given the resizing threshold
288	>	* of 0.75, although with a large variance because of resizing
289	>	* granularity. Ignoring variance, the expected occurrences of
290	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
291	>	* first values are:
292	>	*
293	>	* 0:    0.60653066
294	>	* 1:    0.30326533
295	>	* 2:    0.07581633
296	>	* 3:    0.01263606
297	>	* 4:    0.00157952
298	>	* 5:    0.00015795
299	>	* 6:    0.00001316
300	>	* 7:    0.00000094
301	>	* 8:    0.00000006
302	>	* more: less than 1 in ten million
303	>	*
304	>	* Lock contention probability for two threads accessing distinct
305	>	* elements is roughly 1 / (8 * #elements) under random hashes.
306	>	*
307	>	* Actual hash code distributions encountered in practice
308	>	* sometimes deviate significantly from uniform randomness.  This
309	>	* includes the case when N > (1<<30), so some keys MUST collide.
310	>	* Similarly for dumb or hostile usages in which multiple keys are
311	>	* designed to have identical hash codes. Also, although we guard
312	>	* against the worst effects of this (see method spread), sets of
313	>	* hashes may differ only in bits that do not impact their bin
314	>	* index for a given power-of-two mask.  So we use a secondary
315	>	* strategy that applies when the number of nodes in a bin exceeds
316	>	* a threshold, and at least one of the keys implements
317	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
318	>	* (a specialized form of red-black trees), bounding search time
319	>	* to O(log N).  Each search step in a TreeBin is around twice as
320	>	* slow as in a regular list, but given that N cannot exceed
321	>	* (1<<64) (before running out of addresses) this bounds search
322	>	* steps, lock hold times, etc, to reasonable constants (roughly
323	>	* 100 nodes inspected per operation worst case) so long as keys
324	>	* are Comparable (which is very common -- String, Long, etc).
325	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
326	>	* traversal pointers as regular nodes, so can be traversed in
327	>	* iterators in the same way.
328	>	*
329	>	* The table is resized when occupancy exceeds a percentage
330	>	* threshold (nominally, 0.75, but see below).  Any thread
331	>	* noticing an overfull bin may assist in resizing after the
332	>	* initiating thread allocates and sets up the replacement
333	>	* array. However, rather than stalling, these other threads may
334	>	* proceed with insertions etc.  The use of TreeBins shields us
335	>	* from the worst case effects of overfilling while resizes are in
336	>	* progress.  Resizing proceeds by transferring bins, one by one,
337	>	* from the table to the next table. To enable concurrency, the
338	>	* next table must be (incrementally) prefilled with place-holders
339	>	* serving as reverse forwarders to the old table.  Because we are
340	>	* using power-of-two expansion, the elements from each bin must
341	>	* either stay at same index, or move with a power of two
342	>	* offset. We eliminate unnecessary node creation by catching
343	>	* cases where old nodes can be reused because their next fields
344	>	* won't change.  On average, only about one-sixth of them need
345	>	* cloning when a table doubles. The nodes they replace will be
346	>	* garbage collectable as soon as they are no longer referenced by
347	>	* any reader thread that may be in the midst of concurrently
348	>	* traversing table.  Upon transfer, the old table bin contains
349	>	* only a special forwarding node (with hash field "MOVED") that
350	>	* contains the next table as its key. On encountering a
351	>	* forwarding node, access and update operations restart, using
352	>	* the new table.
353	>	*
354	>	* Each bin transfer requires its bin lock, which can stall
355	>	* waiting for locks while resizing. However, because other
356	>	* threads can join in and help resize rather than contend for
357	>	* locks, average aggregate waits become shorter as resizing
358	>	* progresses.  The transfer operation must also ensure that all
359	>	* accessible bins in both the old and new table are usable by any
360	>	* traversal.  This is arranged by proceeding from the last bin
361	>	* (table.length - 1) up towards the first.  Upon seeing a
362	>	* forwarding node, traversals (see class Traverser) arrange to
363	>	* move to the new table without revisiting nodes.  However, to
364	>	* ensure that no intervening nodes are skipped, bin splitting can
365	>	* only begin after the associated reverse-forwarders are in
366	>	* place.
367	>	*
368	>	* The traversal scheme also applies to partial traversals of
369	>	* ranges of bins (via an alternate Traverser constructor)
370	>	* to support partitioned aggregate operations.  Also, read-only
371	>	* operations give up if ever forwarded to a null table, which
372	>	* provides support for shutdown-style clearing, which is also not
373	>	* currently implemented.
374	>	*
375	>	* Lazy table initialization minimizes footprint until first use,
376	>	* and also avoids resizings when the first operation is from a
377	>	* putAll, constructor with map argument, or deserialization.
378	>	* These cases attempt to override the initial capacity settings,
379	>	* but harmlessly fail to take effect in cases of races.
380	>	*
381	>	* The element count is maintained using a specialization of
382	>	* LongAdder. We need to incorporate a specialization rather than
383	>	* just use a LongAdder in order to access implicit
384	>	* contention-sensing that leads to creation of multiple
385	>	* Cells.  The counter mechanics avoid contention on
386	>	* updates but can encounter cache thrashing if read too
387	>	* frequently during concurrent access. To avoid reading so often,
388	>	* resizing under contention is attempted only upon adding to a
389	>	* bin already holding two or more nodes. Under uniform hash
390	>	* distributions, the probability of this occurring at threshold
391	>	* is around 13%, meaning that only about 1 in 8 puts check
392	>	* threshold (and after resizing, many fewer do so). The bulk
393	>	* putAll operation further reduces contention by only committing
394	>	* count updates upon these size checks.
395	>	*
396	>	* Maintaining API and serialization compatibility with previous
397	>	* versions of this class introduces several oddities. Mainly: We
398	>	* leave untouched but unused constructor arguments refering to
399	>	* concurrencyLevel. We accept a loadFactor constructor argument,
400	>	* but apply it only to initial table capacity (which is the only
401	>	* time that we can guarantee to honor it.) We also declare an
402	>	* unused "Segment" class that is instantiated in minimal form
403	>	* only when serializing.
404		*/
405
406		/* ---------------- Constants -------------- */
407
408		/**
409	<	* The default initial number of table slots for this table.
410	<	* Used when not otherwise specified in constructor.
409	>	* The largest possible table capacity.  This value must be
410	>	* exactly 1<<30 to stay within Java array allocation and indexing
411	>	* bounds for power of two table sizes, and is further required
412	>	* because the top two bits of 32bit hash fields are used for
413	>	* control purposes.
414	>	*/
415	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
416	>
417	>	/**
418	>	* The default initial table capacity.  Must be a power of 2
419	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
420		*/
421	<	private static int DEFAULT_INITIAL_CAPACITY = 16;
421	>	private static final int DEFAULT_CAPACITY = 16;
422
423		/**
424	<	* The maximum capacity, used if a higher value is implicitly
425	<	* specified by either of the constructors with arguments.  MUST
83	<	* be a power of two <= 1<<30 to ensure that entries are indexible
84	<	* using ints.
424	>	* The largest possible (non-power of two) array size.
425	>	* Needed by toArray and related methods.
426		*/
427	<	static final int MAXIMUM_CAPACITY = 1 << 30;
427	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
428
429		/**
430	<	* The default load factor for this table.  Used when not
431	<	* otherwise specified in constructor.
430	>	* The default concurrency level for this table. Unused but
431	>	* defined for compatibility with previous versions of this class.
432		*/
433	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
433	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
434
435		/**
436	<	* The default number of concurrency control segments.
437	<	**/
438	<	private static final int DEFAULT_SEGMENTS = 16;
436	>	* The load factor for this table. Overrides of this value in
437	>	* constructors affect only the initial table capacity.  The
438	>	* actual floating point value isn't normally used -- it is
439	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
440	>	* the associated resizing threshold.
441	>	*/
442	>	private static final float LOAD_FACTOR = 0.75f;
443
444		/**
445	<	* The maximum number of segments to allow; used to bound ctor arguments.
445	>	* The bin count threshold for using a tree rather than list for a
446	>	* bin.  The value reflects the approximate break-even point for
447	>	* using tree-based operations.
448	>	*/
449	>	private static final int TREE_THRESHOLD = 8;
450	>
451	>	/**
452	>	* Minimum number of rebinnings per transfer step. Ranges are
453	>	* subdivided to allow multiple resizer threads.  This value
454	>	* serves as a lower bound to avoid resizers encountering
455	>	* excessive memory contention.  The value should be at least
456	>	* DEFAULT_CAPACITY.
457	>	*/
458	>	private static final int MIN_TRANSFER_STRIDE = 16;
459	>
460	>	/*
461	>	* Encodings for Node hash fields. See above for explanation.
462		*/
463	<	private static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
463	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
464	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
465	>
466	>	/** Number of CPUS, to place bounds on some sizings */
467	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
468	>
469	>	/* ---------------- Counters -------------- */
470	>
471	>	// Adapted from LongAdder and Striped64.
472	>	// See their internal docs for explanation.
473	>
474	>	// A padded cell for distributing counts
475	>	static final class Cell {
476	>	volatile long p0, p1, p2, p3, p4, p5, p6;
477	>	volatile long value;
478	>	volatile long q0, q1, q2, q3, q4, q5, q6;
479	>	Cell(long x) { value = x; }
480	>	}
481
482		/* ---------------- Fields -------------- */
483
484		/**
485	<	* Mask value for indexing into segments. The upper bits of a
486	<	* key's hash code are used to choose the segment.
487	<	**/
488	<	private final int segmentMask;
485	>	* The array of bins. Lazily initialized upon first insertion.
486	>	* Size is always a power of two. Accessed directly by iterators.
487	>	*/
488	>	transient volatile Node<V>[] table;
489
490		/**
491	<	* Shift value for indexing within segments.
492	<	**/
493	<	private final int segmentShift;
491	>	* The next table to use; non-null only while resizing.
492	>	*/
493	>	private transient volatile Node<V>[] nextTable;
494
495		/**
496	<	* The segments, each of which is a specialized hash table
496	>	* Base counter value, used mainly when there is no contention,
497	>	* but also as a fallback during table initialization
498	>	* races. Updated via CAS.
499		*/
500	<	private final Segment[] segments;
500	>	private transient volatile long baseCount;
501
502	<	private transient Set<K> keySet;
503	<	private transient Set<Map.Entry<K,V>> entrySet;
504	<	private transient Collection<V> values;
502	>	/**
503	>	* Table initialization and resizing control.  When negative, the
504	>	* table is being initialized or resized: -1 for initialization,
505	>	* else -(1 + the number of active resizing threads).  Otherwise,
506	>	* when table is null, holds the initial table size to use upon
507	>	* creation, or 0 for default. After initialization, holds the
508	>	* next element count value upon which to resize the table.
509	>	*/
510	>	private transient volatile int sizeCtl;
511
512	<	/* ---------------- Small Utilities -------------- */
512	>	/**
513	>	* The next table index (plus one) to split while resizing.
514	>	*/
515	>	private transient volatile int transferIndex;
516
517		/**
518	<	* Return a hash code for non-null Object x.
130	<	* Uses the same hash code spreader as most other j.u hash tables.
131	<	* @param x the object serving as a key
132	<	* @return the hash code
518	>	* The least available table index to split while resizing.
519		*/
520	<	private static int hash(Object x) {
521	<	int h = x.hashCode();
522	<	h += ~(h << 9);
523	<	h ^=  (h >>> 14);
524	<	h +=  (h << 4);
525	<	h ^=  (h >>> 10);
526	<	return h;
520	>	private transient volatile int transferOrigin;
521	>
522	>	/**
523	>	* Spinlock (locked via CAS) used when resizing and/or creating Cells.
524	>	*/
525	>	private transient volatile int cellsBusy;
526	>
527	>	/**
528	>	* Table of counter cells. When non-null, size is a power of 2.
529	>	*/
530	>	private transient volatile Cell[] counterCells;
531	>
532	>	// views
533	>	private transient KeySetView<K,V> keySet;
534	>	private transient ValuesView<K,V> values;
535	>	private transient EntrySetView<K,V> entrySet;
536	>
537	>	/** For serialization compatibility. Null unless serialized; see below */
538	>	private Segment<K,V>[] segments;
539	>
540	>	/* ---------------- Table element access -------------- */
541	>
542	>	/*
543	>	* Volatile access methods are used for table elements as well as
544	>	* elements of in-progress next table while resizing.  Uses are
545	>	* null checked by callers, and implicitly bounds-checked, relying
546	>	* on the invariants that tab arrays have non-zero size, and all
547	>	* indices are masked with (tab.length - 1) which is never
548	>	* negative and always less than length. Note that, to be correct
549	>	* wrt arbitrary concurrency errors by users, bounds checks must
550	>	* operate on local variables, which accounts for some odd-looking
551	>	* inline assignments below.
552	>	*/
553	>
554	>	@SuppressWarnings("unchecked") static final <V> Node<V> tabAt
555	>	(Node<V>[] tab, int i) { // used by Traverser
556	>	return (Node<V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
557		}
558
559	+	private static final <V> boolean casTabAt
560	+	(Node<V>[] tab, int i, Node<V> c, Node<V> v) {
561	+	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
562	+	}
563	+
564	+	private static final <V> void setTabAt
565	+	(Node<V>[] tab, int i, Node<V> v) {
566	+	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
567	+	}
568	+
569	+	/* ---------------- Nodes -------------- */
570	+
571		/**
572	<	* Return the segment that should be used for key with given hash
572	>	* Key-value entry. Note that this is never exported out as a
573	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
574	>	* field of MOVED are special, and do not contain user keys or
575	>	* values.  Otherwise, keys are never null, and null val fields
576	>	* indicate that a node is in the process of being deleted or
577	>	* created. For purposes of read-only access, a key may be read
578	>	* before a val, but can only be used after checking val to be
579	>	* non-null.
580		*/
581	<	private Segment<K,V> segmentFor(int hash) {
582	<	return (Segment<K,V>) segments[(hash >>> segmentShift) & segmentMask];
581	>	static class Node<V> {
582	>	final int hash;
583	>	final Object key;
584	>	volatile V val;
585	>	volatile Node<V> next;
586	>
587	>	Node(int hash, Object key, V val, Node<V> next) {
588	>	this.hash = hash;
589	>	this.key = key;
590	>	this.val = val;
591	>	this.next = next;
592	>	}
593		}
594
595	<	/* ---------------- Inner Classes -------------- */
595	>	/* ---------------- TreeBins -------------- */
596
597		/**
598	<	* Segments are specialized versions of hash tables.  This
599	<	* subclasses from ReentrantLock opportunistically, just to
600	<	* simplify some locking and avoid separate construction.
601	<	**/
602	<	private static final class Segment<K,V> extends ReentrantLock implements Serializable {
603	<	/*
604	<	* Segments maintain a table of entry lists that are ALWAYS
605	<	* kept in a consistent state, so can be read without locking.
606	<	* Next fields of nodes are immutable (final).  All list
607	<	* additions are performed at the front of each bin. This
608	<	* makes it easy to check changes, and also fast to traverse.
609	<	* When nodes would otherwise be changed, new nodes are
610	<	* created to replace them. This works well for hash tables
611	<	* since the bin lists tend to be short. (The average length
167	<	* is less than two for the default load factor threshold.)
168	<	*
169	<	* Read operations can thus proceed without locking, but rely
170	<	* on a memory barrier to ensure that completed write
171	<	* operations performed by other threads are
172	<	* noticed. Conveniently, the "count" field, tracking the
173	<	* number of elements, can also serve as the volatile variable
174	<	* providing proper read/write barriers. This is convenient
175	<	* because this field needs to be read in many read operations
176	<	* anyway.
177	<	*
178	<	* Implementors note. The basic rules for all this are:
179	<	*
180	<	*   - All unsynchronized read operations must first read the
181	<	*     "count" field, and should not look at table entries if
182	<	*     it is 0.
183	<	*
184	<	*   - All synchronized write operations should write to
185	<	*     the "count" field after updating. The operations must not
186	<	*     take any action that could even momentarily cause
187	<	*     a concurrent read operation to see inconsistent
188	<	*     data. This is made easier by the nature of the read
189	<	*     operations in Map. For example, no operation
190	<	*     can reveal that the table has grown but the threshold
191	<	*     has not yet been updated, so there are no atomicity
192	<	*     requirements for this with respect to reads.
193	<	*
194	<	* As a guide, all critical volatile reads and writes are marked
195	<	* in code comments.
196	<	*/
598	>	* Nodes for use in TreeBins
599	>	*/
600	>	static final class TreeNode<V> extends Node<V> {
601	>	TreeNode<V> parent;  // red-black tree links
602	>	TreeNode<V> left;
603	>	TreeNode<V> right;
604	>	TreeNode<V> prev;    // needed to unlink next upon deletion
605	>	boolean red;
606	>
607	>	TreeNode(int hash, Object key, V val, Node<V> next, TreeNode<V> parent) {
608	>	super(hash, key, val, next);
609	>	this.parent = parent;
610	>	}
611	>	}
612
613	+	/**
614	+	* A specialized form of red-black tree for use in bins
615	+	* whose size exceeds a threshold.
616	+	*
617	+	* TreeBins use a special form of comparison for search and
618	+	* related operations (which is the main reason we cannot use
619	+	* existing collections such as TreeMaps). TreeBins contain
620	+	* Comparable elements, but may contain others, as well as
621	+	* elements that are Comparable but not necessarily Comparable<T>
622	+	* for the same T, so we cannot invoke compareTo among them. To
623	+	* handle this, the tree is ordered primarily by hash value, then
624	+	* by getClass().getName() order, and then by Comparator order
625	+	* among elements of the same class.  On lookup at a node, if
626	+	* elements are not comparable or compare as 0, both left and
627	+	* right children may need to be searched in the case of tied hash
628	+	* values. (This corresponds to the full list search that would be
629	+	* necessary if all elements were non-Comparable and had tied
630	+	* hashes.)  The red-black balancing code is updated from
631	+	* pre-jdk-collections
632	+	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
633	+	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
634	+	* Algorithms" (CLR).
635	+	*
636	+	* TreeBins also maintain a separate locking discipline than
637	+	* regular bins. Because they are forwarded via special MOVED
638	+	* nodes at bin heads (which can never change once established),
639	+	* we cannot use those nodes as locks. Instead, TreeBin
640	+	* extends AbstractQueuedSynchronizer to support a simple form of
641	+	* read-write lock. For update operations and table validation,
642	+	* the exclusive form of lock behaves in the same way as bin-head
643	+	* locks. However, lookups use shared read-lock mechanics to allow
644	+	* multiple readers in the absence of writers.  Additionally,
645	+	* these lookups do not ever block: While the lock is not
646	+	* available, they proceed along the slow traversal path (via
647	+	* next-pointers) until the lock becomes available or the list is
648	+	* exhausted, whichever comes first. (These cases are not fast,
649	+	* but maximize aggregate expected throughput.)  The AQS mechanics
650	+	* for doing this are straightforward.  The lock state is held as
651	+	* AQS getState().  Read counts are negative; the write count (1)
652	+	* is positive.  There are no signalling preferences among readers
653	+	* and writers. Since we don't need to export full Lock API, we
654	+	* just override the minimal AQS methods and use them directly.
655	+	*/
656	+	static final class TreeBin<V> extends AbstractQueuedSynchronizer {
657		private static final long serialVersionUID = 2249069246763182397L;
658	+	transient TreeNode<V> root;  // root of tree
659	+	transient TreeNode<V> first; // head of next-pointer list
660
661	<	/**
662	<	* The number of elements in this segment's region.
663	<	**/
664	<	transient volatile int count;
661	>	/* AQS overrides */
662	>	public final boolean isHeldExclusively() { return getState() > 0; }
663	>	public final boolean tryAcquire(int ignore) {
664	>	if (compareAndSetState(0, 1)) {
665	>	setExclusiveOwnerThread(Thread.currentThread());
666	>	return true;
667	>	}
668	>	return false;
669	>	}
670	>	public final boolean tryRelease(int ignore) {
671	>	setExclusiveOwnerThread(null);
672	>	setState(0);
673	>	return true;
674	>	}
675	>	public final int tryAcquireShared(int ignore) {
676	>	for (int c;;) {
677	>	if ((c = getState()) > 0)
678	>	return -1;
679	>	if (compareAndSetState(c, c -1))
680	>	return 1;
681	>	}
682	>	}
683	>	public final boolean tryReleaseShared(int ignore) {
684	>	int c;
685	>	do {} while (!compareAndSetState(c = getState(), c + 1));
686	>	return c == -1;
687	>	}
688	>
689	>	/** From CLR */
690	>	private void rotateLeft(TreeNode<V> p) {
691	>	if (p != null) {
692	>	TreeNode<V> r = p.right, pp, rl;
693	>	if ((rl = p.right = r.left) != null)
694	>	rl.parent = p;
695	>	if ((pp = r.parent = p.parent) == null)
696	>	root = r;
697	>	else if (pp.left == p)
698	>	pp.left = r;
699	>	else
700	>	pp.right = r;
701	>	r.left = p;
702	>	p.parent = r;
703	>	}
704	>	}
705
706	<	/**
707	<	* Number of updates; used for checking lack of modifications
708	<	* in bulk-read methods.
709	<	*/
710	<	transient int modCount;
706	>	/** From CLR */
707	>	private void rotateRight(TreeNode<V> p) {
708	>	if (p != null) {
709	>	TreeNode<V> l = p.left, pp, lr;
710	>	if ((lr = p.left = l.right) != null)
711	>	lr.parent = p;
712	>	if ((pp = l.parent = p.parent) == null)
713	>	root = l;
714	>	else if (pp.right == p)
715	>	pp.right = l;
716	>	else
717	>	pp.left = l;
718	>	l.right = p;
719	>	p.parent = l;
720	>	}
721	>	}
722
723		/**
724	<	* The table is rehashed when its size exceeds this threshold.
725	<	* (The value of this field is always (int)(capacity *
214	<	* loadFactor).)
724	>	* Returns the TreeNode (or null if not found) for the given key
725	>	* starting at given root.
726		*/
727	<	private transient int threshold;
727	>	@SuppressWarnings("unchecked") final TreeNode<V> getTreeNode
728	>	(int h, Object k, TreeNode<V> p) {
729	>	Class<?> c = k.getClass();
730	>	while (p != null) {
731	>	int dir, ph;  Object pk; Class<?> pc;
732	>	if ((ph = p.hash) == h) {
733	>	if ((pk = p.key) == k || k.equals(pk))
734	>	return p;
735	>	if (c != (pc = pk.getClass()) ||
736	>	!(k instanceof Comparable) ||
737	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
738	>	if ((dir = (c == pc) ? 0 :
739	>	c.getName().compareTo(pc.getName())) == 0) {
740	>	TreeNode<V> r = null, pl, pr; // check both sides
741	>	if ((pr = p.right) != null && h >= pr.hash &&
742	>	(r = getTreeNode(h, k, pr)) != null)
743	>	return r;
744	>	else if ((pl = p.left) != null && h <= pl.hash)
745	>	dir = -1;
746	>	else // nothing there
747	>	return null;
748	>	}
749	>	}
750	>	}
751	>	else
752	>	dir = (h < ph) ? -1 : 1;
753	>	p = (dir > 0) ? p.right : p.left;
754	>	}
755	>	return null;
756	>	}
757
758		/**
759	<	* The per-segment table
759	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
760	>	* read-lock to call getTreeNode, but during failure to get
761	>	* lock, searches along next links.
762		*/
763	<	transient HashEntry[] table;
763	>	final V getValue(int h, Object k) {
764	>	Node<V> r = null;
765	>	int c = getState(); // Must read lock state first
766	>	for (Node<V> e = first; e != null; e = e.next) {
767	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
768	>	try {
769	>	r = getTreeNode(h, k, root);
770	>	} finally {
771	>	releaseShared(0);
772	>	}
773	>	break;
774	>	}
775	>	else if (e.hash == h && k.equals(e.key)) {
776	>	r = e;
777	>	break;
778	>	}
779	>	else
780	>	c = getState();
781	>	}
782	>	return r == null ? null : r.val;
783	>	}
784
785		/**
786	<	* The load factor for the hash table.  Even though this value
787	<	* is same for all segments, it is replicated to avoid needing
226	<	* links to outer object.
227	<	* @serial
786	>	* Finds or adds a node.
787	>	* @return null if added
788		*/
789	<	private final float loadFactor;
789	>	@SuppressWarnings("unchecked") final TreeNode<V> putTreeNode
790	>	(int h, Object k, V v) {
791	>	Class<?> c = k.getClass();
792	>	TreeNode<V> pp = root, p = null;
793	>	int dir = 0;
794	>	while (pp != null) { // find existing node or leaf to insert at
795	>	int ph;  Object pk; Class<?> pc;
796	>	p = pp;
797	>	if ((ph = p.hash) == h) {
798	>	if ((pk = p.key) == k || k.equals(pk))
799	>	return p;
800	>	if (c != (pc = pk.getClass()) ||
801	>	!(k instanceof Comparable) ||
802	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
803	>	TreeNode<V> s = null, r = null, pr;
804	>	if ((dir = (c == pc) ? 0 :
805	>	c.getName().compareTo(pc.getName())) == 0) {
806	>	if ((pr = p.right) != null && h >= pr.hash &&
807	>	(r = getTreeNode(h, k, pr)) != null)
808	>	return r;
809	>	else // continue left
810	>	dir = -1;
811	>	}
812	>	else if ((pr = p.right) != null && h >= pr.hash)
813	>	s = pr;
814	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
815	>	return r;
816	>	}
817	>	}
818	>	else
819	>	dir = (h < ph) ? -1 : 1;
820	>	pp = (dir > 0) ? p.right : p.left;
821	>	}
822
823	<	Segment(int initialCapacity, float lf) {
824	<	loadFactor = lf;
825	<	setTable(new HashEntry[initialCapacity]);
823	>	TreeNode<V> f = first;
824	>	TreeNode<V> x = first = new TreeNode<V>(h, k, v, f, p);
825	>	if (p == null)
826	>	root = x;
827	>	else { // attach and rebalance; adapted from CLR
828	>	TreeNode<V> xp, xpp;
829	>	if (f != null)
830	>	f.prev = x;
831	>	if (dir <= 0)
832	>	p.left = x;
833	>	else
834	>	p.right = x;
835	>	x.red = true;
836	>	while (x != null && (xp = x.parent) != null && xp.red &&
837	>	(xpp = xp.parent) != null) {
838	>	TreeNode<V> xppl = xpp.left;
839	>	if (xp == xppl) {
840	>	TreeNode<V> y = xpp.right;
841	>	if (y != null && y.red) {
842	>	y.red = false;
843	>	xp.red = false;
844	>	xpp.red = true;
845	>	x = xpp;
846	>	}
847	>	else {
848	>	if (x == xp.right) {
849	>	rotateLeft(x = xp);
850	>	xpp = (xp = x.parent) == null ? null : xp.parent;
851	>	}
852	>	if (xp != null) {
853	>	xp.red = false;
854	>	if (xpp != null) {
855	>	xpp.red = true;
856	>	rotateRight(xpp);
857	>	}
858	>	}
859	>	}
860	>	}
861	>	else {
862	>	TreeNode<V> y = xppl;
863	>	if (y != null && y.red) {
864	>	y.red = false;
865	>	xp.red = false;
866	>	xpp.red = true;
867	>	x = xpp;
868	>	}
869	>	else {
870	>	if (x == xp.left) {
871	>	rotateRight(x = xp);
872	>	xpp = (xp = x.parent) == null ? null : xp.parent;
873	>	}
874	>	if (xp != null) {
875	>	xp.red = false;
876	>	if (xpp != null) {
877	>	xpp.red = true;
878	>	rotateLeft(xpp);
879	>	}
880	>	}
881	>	}
882	>	}
883	>	}
884	>	TreeNode<V> r = root;
885	>	if (r != null && r.red)
886	>	r.red = false;
887	>	}
888	>	return null;
889		}
890
891		/**
892	<	* Set table to new HashEntry array.
893	<	* Call only while holding lock or in constructor.
894	<	**/
895	<	private void setTable(HashEntry[] newTable) {
896	<	table = newTable;
897	<	threshold = (int)(newTable.length * loadFactor);
898	<	count = count; // write-volatile
892	>	* Removes the given node, that must be present before this
893	>	* call.  This is messier than typical red-black deletion code
894	>	* because we cannot swap the contents of an interior node
895	>	* with a leaf successor that is pinned by "next" pointers
896	>	* that are accessible independently of lock. So instead we
897	>	* swap the tree linkages.
898	>	*/
899	>	final void deleteTreeNode(TreeNode<V> p) {
900	>	TreeNode<V> next = (TreeNode<V>)p.next; // unlink traversal pointers
901	>	TreeNode<V> pred = p.prev;
902	>	if (pred == null)
903	>	first = next;
904	>	else
905	>	pred.next = next;
906	>	if (next != null)
907	>	next.prev = pred;
908	>	TreeNode<V> replacement;
909	>	TreeNode<V> pl = p.left;
910	>	TreeNode<V> pr = p.right;
911	>	if (pl != null && pr != null) {
912	>	TreeNode<V> s = pr, sl;
913	>	while ((sl = s.left) != null) // find successor
914	>	s = sl;
915	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
916	>	TreeNode<V> sr = s.right;
917	>	TreeNode<V> pp = p.parent;
918	>	if (s == pr) { // p was s's direct parent
919	>	p.parent = s;
920	>	s.right = p;
921	>	}
922	>	else {
923	>	TreeNode<V> sp = s.parent;
924	>	if ((p.parent = sp) != null) {
925	>	if (s == sp.left)
926	>	sp.left = p;
927	>	else
928	>	sp.right = p;
929	>	}
930	>	if ((s.right = pr) != null)
931	>	pr.parent = s;
932	>	}
933	>	p.left = null;
934	>	if ((p.right = sr) != null)
935	>	sr.parent = p;
936	>	if ((s.left = pl) != null)
937	>	pl.parent = s;
938	>	if ((s.parent = pp) == null)
939	>	root = s;
940	>	else if (p == pp.left)
941	>	pp.left = s;
942	>	else
943	>	pp.right = s;
944	>	replacement = sr;
945	>	}
946	>	else
947	>	replacement = (pl != null) ? pl : pr;
948	>	TreeNode<V> pp = p.parent;
949	>	if (replacement == null) {
950	>	if (pp == null) {
951	>	root = null;
952	>	return;
953	>	}
954	>	replacement = p;
955	>	}
956	>	else {
957	>	replacement.parent = pp;
958	>	if (pp == null)
959	>	root = replacement;
960	>	else if (p == pp.left)
961	>	pp.left = replacement;
962	>	else
963	>	pp.right = replacement;
964	>	p.left = p.right = p.parent = null;
965	>	}
966	>	if (!p.red) { // rebalance, from CLR
967	>	TreeNode<V> x = replacement;
968	>	while (x != null) {
969	>	TreeNode<V> xp, xpl;
970	>	if (x.red || (xp = x.parent) == null) {
971	>	x.red = false;
972	>	break;
973	>	}
974	>	if (x == (xpl = xp.left)) {
975	>	TreeNode<V> sib = xp.right;
976	>	if (sib != null && sib.red) {
977	>	sib.red = false;
978	>	xp.red = true;
979	>	rotateLeft(xp);
980	>	sib = (xp = x.parent) == null ? null : xp.right;
981	>	}
982	>	if (sib == null)
983	>	x = xp;
984	>	else {
985	>	TreeNode<V> sl = sib.left, sr = sib.right;
986	>	if ((sr == null || !sr.red) &&
987	>	(sl == null || !sl.red)) {
988	>	sib.red = true;
989	>	x = xp;
990	>	}
991	>	else {
992	>	if (sr == null || !sr.red) {
993	>	if (sl != null)
994	>	sl.red = false;
995	>	sib.red = true;
996	>	rotateRight(sib);
997	>	sib = (xp = x.parent) == null ?
998	>	null : xp.right;
999	>	}
1000	>	if (sib != null) {
1001	>	sib.red = (xp == null) ? false : xp.red;
1002	>	if ((sr = sib.right) != null)
1003	>	sr.red = false;
1004	>	}
1005	>	if (xp != null) {
1006	>	xp.red = false;
1007	>	rotateLeft(xp);
1008	>	}
1009	>	x = root;
1010	>	}
1011	>	}
1012	>	}
1013	>	else { // symmetric
1014	>	TreeNode<V> sib = xpl;
1015	>	if (sib != null && sib.red) {
1016	>	sib.red = false;
1017	>	xp.red = true;
1018	>	rotateRight(xp);
1019	>	sib = (xp = x.parent) == null ? null : xp.left;
1020	>	}
1021	>	if (sib == null)
1022	>	x = xp;
1023	>	else {
1024	>	TreeNode<V> sl = sib.left, sr = sib.right;
1025	>	if ((sl == null || !sl.red) &&
1026	>	(sr == null || !sr.red)) {
1027	>	sib.red = true;
1028	>	x = xp;
1029	>	}
1030	>	else {
1031	>	if (sl == null || !sl.red) {
1032	>	if (sr != null)
1033	>	sr.red = false;
1034	>	sib.red = true;
1035	>	rotateLeft(sib);
1036	>	sib = (xp = x.parent) == null ?
1037	>	null : xp.left;
1038	>	}
1039	>	if (sib != null) {
1040	>	sib.red = (xp == null) ? false : xp.red;
1041	>	if ((sl = sib.left) != null)
1042	>	sl.red = false;
1043	>	}
1044	>	if (xp != null) {
1045	>	xp.red = false;
1046	>	rotateRight(xp);
1047	>	}
1048	>	x = root;
1049	>	}
1050	>	}
1051	>	}
1052	>	}
1053	>	}
1054	>	if (p == replacement && (pp = p.parent) != null) {
1055	>	if (p == pp.left) // detach pointers
1056	>	pp.left = null;
1057	>	else if (p == pp.right)
1058	>	pp.right = null;
1059	>	p.parent = null;
1060	>	}
1061	>	}
1062	>	}
1063	>
1064	>	/* ---------------- Collision reduction methods -------------- */
1065	>
1066	>	/**
1067	>	* Spreads higher bits to lower, and also forces top bit to 0.
1068	>	* Because the table uses power-of-two masking, sets of hashes
1069	>	* that vary only in bits above the current mask will always
1070	>	* collide. (Among known examples are sets of Float keys holding
1071	>	* consecutive whole numbers in small tables.)  To counter this,
1072	>	* we apply a transform that spreads the impact of higher bits
1073	>	* downward. There is a tradeoff between speed, utility, and
1074	>	* quality of bit-spreading. Because many common sets of hashes
1075	>	* are already reasonably distributed across bits (so don't benefit
1076	>	* from spreading), and because we use trees to handle large sets
1077	>	* of collisions in bins, we don't need excessively high quality.
1078	>	*/
1079	>	private static final int spread(int h) {
1080	>	h ^= (h >>> 18) ^ (h >>> 12);
1081	>	return (h ^ (h >>> 10)) & HASH_BITS;
1082	>	}
1083	>
1084	>	/**
1085	>	* Replaces a list bin with a tree bin if key is comparable.  Call
1086	>	* only when locked.
1087	>	*/
1088	>	private final void replaceWithTreeBin(Node<V>[] tab, int index, Object key) {
1089	>	if (key instanceof Comparable) {
1090	>	TreeBin<V> t = new TreeBin<V>();
1091	>	for (Node<V> e = tabAt(tab, index); e != null; e = e.next)
1092	>	t.putTreeNode(e.hash, e.key, e.val);
1093	>	setTabAt(tab, index, new Node<V>(MOVED, t, null, null));
1094		}
1095	+	}
1096
1097	<	/* Specialized implementations of map methods */
1097	>	/* ---------------- Internal access and update methods -------------- */
1098
1099	<	V get(K key, int hash) {
1100	<	if (count != 0) { // read-volatile
1101	<	HashEntry[] tab = table;
1102	<	int index = hash & (tab.length - 1);
1103	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
1104	<	while (e != null) {
1105	<	if (e.hash == hash && key.equals(e.key))
1106	<	return e.value;
1107	<	e = e.next;
1099	>	/** Implementation for get and containsKey */
1100	>	@SuppressWarnings("unchecked") private final V internalGet(Object k) {
1101	>	int h = spread(k.hashCode());
1102	>	retry: for (Node<V>[] tab = table; tab != null;) {
1103	>	Node<V> e; Object ek; V ev; int eh; // locals to read fields once
1104	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1105	>	if ((eh = e.hash) < 0) {
1106	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1107	>	return ((TreeBin<V>)ek).getValue(h, k);
1108	>	else {                      // restart with new table
1109	>	tab = (Node<V>[])ek;
1110	>	continue retry;
1111	>	}
1112		}
1113	+	else if (eh == h && (ev = e.val) != null &&
1114	+	((ek = e.key) == k || k.equals(ek)))
1115	+	return ev;
1116		}
1117	<	return null;
1117	>	break;
1118		}
1119	+	return null;
1120	+	}
1121
1122	<	boolean containsKey(Object key, int hash) {
1123	<	if (count != 0) { // read-volatile
1124	<	HashEntry[] tab = table;
1125	<	int index = hash & (tab.length - 1);
1126	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
1127	<	while (e != null) {
1128	<	if (e.hash == hash && key.equals(e.key))
1129	<	return true;
1130	<	e = e.next;
1122	>	/**
1123	>	* Implementation for the four public remove/replace methods:
1124	>	* Replaces node value with v, conditional upon match of cv if
1125	>	* non-null.  If resulting value is null, delete.
1126	>	*/
1127	>	@SuppressWarnings("unchecked") private final V internalReplace
1128	>	(Object k, V v, Object cv) {
1129	>	int h = spread(k.hashCode());
1130	>	V oldVal = null;
1131	>	for (Node<V>[] tab = table;;) {
1132	>	Node<V> f; int i, fh; Object fk;
1133	>	if (tab == null ||
1134	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1135	>	break;
1136	>	else if ((fh = f.hash) < 0) {
1137	>	if ((fk = f.key) instanceof TreeBin) {
1138	>	TreeBin<V> t = (TreeBin<V>)fk;
1139	>	boolean validated = false;
1140	>	boolean deleted = false;
1141	>	t.acquire(0);
1142	>	try {
1143	>	if (tabAt(tab, i) == f) {
1144	>	validated = true;
1145	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1146	>	if (p != null) {
1147	>	V pv = p.val;
1148	>	if (cv == null || cv == pv || cv.equals(pv)) {
1149	>	oldVal = pv;
1150	>	if ((p.val = v) == null) {
1151	>	deleted = true;
1152	>	t.deleteTreeNode(p);
1153	>	}
1154	>	}
1155	>	}
1156	>	}
1157	>	} finally {
1158	>	t.release(0);
1159	>	}
1160	>	if (validated) {
1161	>	if (deleted)
1162	>	addCount(-1L, -1);
1163	>	break;
1164	>	}
1165	>	}
1166	>	else
1167	>	tab = (Node<V>[])fk;
1168	>	}
1169	>	else if (fh != h && f.next == null) // precheck
1170	>	break;                          // rules out possible existence
1171	>	else {
1172	>	boolean validated = false;
1173	>	boolean deleted = false;
1174	>	synchronized (f) {
1175	>	if (tabAt(tab, i) == f) {
1176	>	validated = true;
1177	>	for (Node<V> e = f, pred = null;;) {
1178	>	Object ek; V ev;
1179	>	if (e.hash == h &&
1180	>	((ev = e.val) != null) &&
1181	>	((ek = e.key) == k || k.equals(ek))) {
1182	>	if (cv == null || cv == ev || cv.equals(ev)) {
1183	>	oldVal = ev;
1184	>	if ((e.val = v) == null) {
1185	>	deleted = true;
1186	>	Node<V> en = e.next;
1187	>	if (pred != null)
1188	>	pred.next = en;
1189	>	else
1190	>	setTabAt(tab, i, en);
1191	>	}
1192	>	}
1193	>	break;
1194	>	}
1195	>	pred = e;
1196	>	if ((e = e.next) == null)
1197	>	break;
1198	>	}
1199	>	}
1200	>	}
1201	>	if (validated) {
1202	>	if (deleted)
1203	>	addCount(-1L, -1);
1204	>	break;
1205		}
1206		}
273	–	return false;
1207		}
1208	+	return oldVal;
1209	+	}
1210	+
1211	+	/*
1212	+	* Internal versions of insertion methods
1213	+	* All have the same basic structure as the first (internalPut):
1214	+	*  1. If table uninitialized, create
1215	+	*  2. If bin empty, try to CAS new node
1216	+	*  3. If bin stale, use new table
1217	+	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1218	+	*  5. Lock and validate; if valid, scan and add or update
1219	+	*
1220	+	* The putAll method differs mainly in attempting to pre-allocate
1221	+	* enough table space, and also more lazily performs count updates
1222	+	* and checks.
1223	+	*
1224	+	* Most of the function-accepting methods can't be factored nicely
1225	+	* because they require different functional forms, so instead
1226	+	* sprawl out similar mechanics.
1227	+	*/
1228
1229	<	boolean containsValue(Object value) {
1230	<	if (count != 0) { // read-volatile
1231	<	HashEntry[] tab = table;
1232	<	int len = tab.length;
1233	<	for (int i = 0 ; i < len; i++)
1234	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i] ; e != null ; e = e.next)
1235	<	if (value.equals(e.value))
1236	<	return true;
1229	>	/** Implementation for put and putIfAbsent */
1230	>	@SuppressWarnings("unchecked") private final V internalPut
1231	>	(K k, V v, boolean onlyIfAbsent) {
1232	>	if (k == null || v == null) throw new NullPointerException();
1233	>	int h = spread(k.hashCode());
1234	>	int len = 0;
1235	>	for (Node<V>[] tab = table;;) {
1236	>	int i, fh; Node<V> f; Object fk; V fv;
1237	>	if (tab == null)
1238	>	tab = initTable();
1239	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1240	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null)))
1241	>	break;                   // no lock when adding to empty bin
1242	>	}
1243	>	else if ((fh = f.hash) < 0) {
1244	>	if ((fk = f.key) instanceof TreeBin) {
1245	>	TreeBin<V> t = (TreeBin<V>)fk;
1246	>	V oldVal = null;
1247	>	t.acquire(0);
1248	>	try {
1249	>	if (tabAt(tab, i) == f) {
1250	>	len = 2;
1251	>	TreeNode<V> p = t.putTreeNode(h, k, v);
1252	>	if (p != null) {
1253	>	oldVal = p.val;
1254	>	if (!onlyIfAbsent)
1255	>	p.val = v;
1256	>	}
1257	>	}
1258	>	} finally {
1259	>	t.release(0);
1260	>	}
1261	>	if (len != 0) {
1262	>	if (oldVal != null)
1263	>	return oldVal;
1264	>	break;
1265	>	}
1266	>	}
1267	>	else
1268	>	tab = (Node<V>[])fk;
1269	>	}
1270	>	else if (onlyIfAbsent && fh == h && (fv = f.val) != null &&
1271	>	((fk = f.key) == k || k.equals(fk))) // peek while nearby
1272	>	return fv;
1273	>	else {
1274	>	V oldVal = null;
1275	>	synchronized (f) {
1276	>	if (tabAt(tab, i) == f) {
1277	>	len = 1;
1278	>	for (Node<V> e = f;; ++len) {
1279	>	Object ek; V ev;
1280	>	if (e.hash == h &&
1281	>	(ev = e.val) != null &&
1282	>	((ek = e.key) == k || k.equals(ek))) {
1283	>	oldVal = ev;
1284	>	if (!onlyIfAbsent)
1285	>	e.val = v;
1286	>	break;
1287	>	}
1288	>	Node<V> last = e;
1289	>	if ((e = e.next) == null) {
1290	>	last.next = new Node<V>(h, k, v, null);
1291	>	if (len >= TREE_THRESHOLD)
1292	>	replaceWithTreeBin(tab, i, k);
1293	>	break;
1294	>	}
1295	>	}
1296	>	}
1297	>	}
1298	>	if (len != 0) {
1299	>	if (oldVal != null)
1300	>	return oldVal;
1301	>	break;
1302	>	}
1303		}
285	–	return false;
1304		}
1305	+	addCount(1L, len);
1306	+	return null;
1307	+	}
1308
1309	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
1310	<	lock();
1311	<	try {
1312	<	int c = count;
1313	<	HashEntry[] tab = table;
1314	<	int index = hash & (tab.length - 1);
1315	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1316	<
1317	<	for (HashEntry<K,V> e = first; e != null; e = (HashEntry<K,V>) e.next) {
1318	<	if (e.hash == hash && key.equals(e.key)) {
1319	<	V oldValue = e.value;
1320	<	if (!onlyIfAbsent)
1321	<	e.value = value;
1322	<	++modCount;
1323	<	count = c; // write-volatile
1324	<	return oldValue;
1309	>	/** Implementation for computeIfAbsent */
1310	>	@SuppressWarnings("unchecked") private final V internalComputeIfAbsent
1311	>	(K k, Function<? super K, ? extends V> mf) {
1312	>	if (k == null || mf == null)
1313	>	throw new NullPointerException();
1314	>	int h = spread(k.hashCode());
1315	>	V val = null;
1316	>	int len = 0;
1317	>	for (Node<V>[] tab = table;;) {
1318	>	Node<V> f; int i; Object fk;
1319	>	if (tab == null)
1320	>	tab = initTable();
1321	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1322	>	Node<V> node = new Node<V>(h, k, null, null);
1323	>	synchronized (node) {
1324	>	if (casTabAt(tab, i, null, node)) {
1325	>	len = 1;
1326	>	try {
1327	>	if ((val = mf.apply(k)) != null)
1328	>	node.val = val;
1329	>	} finally {
1330	>	if (val == null)
1331	>	setTabAt(tab, i, null);
1332	>	}
1333		}
1334		}
1335	+	if (len != 0)
1336	+	break;
1337	+	}
1338	+	else if (f.hash < 0) {
1339	+	if ((fk = f.key) instanceof TreeBin) {
1340	+	TreeBin<V> t = (TreeBin<V>)fk;
1341	+	boolean added = false;
1342	+	t.acquire(0);
1343	+	try {
1344	+	if (tabAt(tab, i) == f) {
1345	+	len = 1;
1346	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1347	+	if (p != null)
1348	+	val = p.val;
1349	+	else if ((val = mf.apply(k)) != null) {
1350	+	added = true;
1351	+	len = 2;
1352	+	t.putTreeNode(h, k, val);
1353	+	}
1354	+	}
1355	+	} finally {
1356	+	t.release(0);
1357	+	}
1358	+	if (len != 0) {
1359	+	if (!added)
1360	+	return val;
1361	+	break;
1362	+	}
1363	+	}
1364	+	else
1365	+	tab = (Node<V>[])fk;
1366	+	}
1367	+	else {
1368	+	for (Node<V> e = f; e != null; e = e.next) { // prescan
1369	+	Object ek; V ev;
1370	+	if (e.hash == h && (ev = e.val) != null &&
1371	+	((ek = e.key) == k || k.equals(ek)))
1372	+	return ev;
1373	+	}
1374	+	boolean added = false;
1375	+	synchronized (f) {
1376	+	if (tabAt(tab, i) == f) {
1377	+	len = 1;
1378	+	for (Node<V> e = f;; ++len) {
1379	+	Object ek; V ev;
1380	+	if (e.hash == h &&
1381	+	(ev = e.val) != null &&
1382	+	((ek = e.key) == k || k.equals(ek))) {
1383	+	val = ev;
1384	+	break;
1385	+	}
1386	+	Node<V> last = e;
1387	+	if ((e = e.next) == null) {
1388	+	if ((val = mf.apply(k)) != null) {
1389	+	added = true;
1390	+	last.next = new Node<V>(h, k, val, null);
1391	+	if (len >= TREE_THRESHOLD)
1392	+	replaceWithTreeBin(tab, i, k);
1393	+	}
1394	+	break;
1395	+	}
1396	+	}
1397	+	}
1398	+	}
1399	+	if (len != 0) {
1400	+	if (!added)
1401	+	return val;
1402	+	break;
1403	+	}
1404	+	}
1405	+	}
1406	+	if (val != null)
1407	+	addCount(1L, len);
1408	+	return val;
1409	+	}
1410
1411	<	tab[index] = new HashEntry<K,V>(hash, key, value, first);
1412	<	++modCount;
1413	<	++c;
1414	<	count = c; // write-volatile
1415	<	if (c > threshold)
1416	<	setTable(rehash(tab));
1417	<	return null;
1418	<	} finally {
1419	<	unlock();
1411	>	/** Implementation for compute */
1412	>	@SuppressWarnings("unchecked") private final V internalCompute
1413	>	(K k, boolean onlyIfPresent,
1414	>	BiFunction<? super K, ? super V, ? extends V> mf) {
1415	>	if (k == null || mf == null)
1416	>	throw new NullPointerException();
1417	>	int h = spread(k.hashCode());
1418	>	V val = null;
1419	>	int delta = 0;
1420	>	int len = 0;
1421	>	for (Node<V>[] tab = table;;) {
1422	>	Node<V> f; int i, fh; Object fk;
1423	>	if (tab == null)
1424	>	tab = initTable();
1425	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1426	>	if (onlyIfPresent)
1427	>	break;
1428	>	Node<V> node = new Node<V>(h, k, null, null);
1429	>	synchronized (node) {
1430	>	if (casTabAt(tab, i, null, node)) {
1431	>	try {
1432	>	len = 1;
1433	>	if ((val = mf.apply(k, null)) != null) {
1434	>	node.val = val;
1435	>	delta = 1;
1436	>	}
1437	>	} finally {
1438	>	if (delta == 0)
1439	>	setTabAt(tab, i, null);
1440	>	}
1441	>	}
1442	>	}
1443	>	if (len != 0)
1444	>	break;
1445	>	}
1446	>	else if ((fh = f.hash) < 0) {
1447	>	if ((fk = f.key) instanceof TreeBin) {
1448	>	TreeBin<V> t = (TreeBin<V>)fk;
1449	>	t.acquire(0);
1450	>	try {
1451	>	if (tabAt(tab, i) == f) {
1452	>	len = 1;
1453	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1454	>	if (p == null && onlyIfPresent)
1455	>	break;
1456	>	V pv = (p == null) ? null : p.val;
1457	>	if ((val = mf.apply(k, pv)) != null) {
1458	>	if (p != null)
1459	>	p.val = val;
1460	>	else {
1461	>	len = 2;
1462	>	delta = 1;
1463	>	t.putTreeNode(h, k, val);
1464	>	}
1465	>	}
1466	>	else if (p != null) {
1467	>	delta = -1;
1468	>	t.deleteTreeNode(p);
1469	>	}
1470	>	}
1471	>	} finally {
1472	>	t.release(0);
1473	>	}
1474	>	if (len != 0)
1475	>	break;
1476	>	}
1477	>	else
1478	>	tab = (Node<V>[])fk;
1479	>	}
1480	>	else {
1481	>	synchronized (f) {
1482	>	if (tabAt(tab, i) == f) {
1483	>	len = 1;
1484	>	for (Node<V> e = f, pred = null;; ++len) {
1485	>	Object ek; V ev;
1486	>	if (e.hash == h &&
1487	>	(ev = e.val) != null &&
1488	>	((ek = e.key) == k || k.equals(ek))) {
1489	>	val = mf.apply(k, ev);
1490	>	if (val != null)
1491	>	e.val = val;
1492	>	else {
1493	>	delta = -1;
1494	>	Node<V> en = e.next;
1495	>	if (pred != null)
1496	>	pred.next = en;
1497	>	else
1498	>	setTabAt(tab, i, en);
1499	>	}
1500	>	break;
1501	>	}
1502	>	pred = e;
1503	>	if ((e = e.next) == null) {
1504	>	if (!onlyIfPresent &&
1505	>	(val = mf.apply(k, null)) != null) {
1506	>	pred.next = new Node<V>(h, k, val, null);
1507	>	delta = 1;
1508	>	if (len >= TREE_THRESHOLD)
1509	>	replaceWithTreeBin(tab, i, k);
1510	>	}
1511	>	break;
1512	>	}
1513	>	}
1514	>	}
1515	>	}
1516	>	if (len != 0)
1517	>	break;
1518		}
1519		}
1520	+	if (delta != 0)
1521	+	addCount((long)delta, len);
1522	+	return val;
1523	+	}
1524
1525	<	private HashEntry[] rehash(HashEntry[] oldTable) {
1526	<	int oldCapacity = oldTable.length;
1527	<	if (oldCapacity >= MAXIMUM_CAPACITY)
1528	<	return oldTable;
1529	<
1530	<	/*
1531	<	* Reclassify nodes in each list to new Map.  Because we are
1532	<	* using power-of-two expansion, the elements from each bin
1533	<	* must either stay at same index, or move with a power of two
1534	<	* offset. We eliminate unnecessary node creation by catching
1535	<	* cases where old nodes can be reused because their next
1536	<	* fields won't change. Statistically, at the default
1537	<	* threshhold, only about one-sixth of them need cloning when
1538	<	* a table doubles. The nodes they replace will be garbage
1539	<	* collectable as soon as they are no longer referenced by any
1540	<	* reader thread that may be in the midst of traversing table
1541	<	* right now.
1542	<	*/
1543	<
1544	<	HashEntry[] newTable = new HashEntry[oldCapacity << 1];
1545	<	int sizeMask = newTable.length - 1;
1546	<	for (int i = 0; i < oldCapacity ; i++) {
1547	<	// We need to guarantee that any existing reads of old Map can
1548	<	//  proceed. So we cannot yet null out each bin.
1549	<	HashEntry<K,V> e = (HashEntry<K,V>)oldTable[i];
1550	<
1551	<	if (e != null) {
1552	<	HashEntry<K,V> next = e.next;
1553	<	int idx = e.hash & sizeMask;
1554	<
1555	<	//  Single node on list
1556	<	if (next == null)
1557	<	newTable[idx] = e;
1525	>	/** Implementation for merge */
1526	>	@SuppressWarnings("unchecked") private final V internalMerge
1527	>	(K k, V v, BiFunction<? super V, ? super V, ? extends V> mf) {
1528	>	if (k == null || v == null || mf == null)
1529	>	throw new NullPointerException();
1530	>	int h = spread(k.hashCode());
1531	>	V val = null;
1532	>	int delta = 0;
1533	>	int len = 0;
1534	>	for (Node<V>[] tab = table;;) {
1535	>	int i; Node<V> f; Object fk; V fv;
1536	>	if (tab == null)
1537	>	tab = initTable();
1538	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1539	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1540	>	delta = 1;
1541	>	val = v;
1542	>	break;
1543	>	}
1544	>	}
1545	>	else if (f.hash < 0) {
1546	>	if ((fk = f.key) instanceof TreeBin) {
1547	>	TreeBin<V> t = (TreeBin<V>)fk;
1548	>	t.acquire(0);
1549	>	try {
1550	>	if (tabAt(tab, i) == f) {
1551	>	len = 1;
1552	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1553	>	val = (p == null) ? v : mf.apply(p.val, v);
1554	>	if (val != null) {
1555	>	if (p != null)
1556	>	p.val = val;
1557	>	else {
1558	>	len = 2;
1559	>	delta = 1;
1560	>	t.putTreeNode(h, k, val);
1561	>	}
1562	>	}
1563	>	else if (p != null) {
1564	>	delta = -1;
1565	>	t.deleteTreeNode(p);
1566	>	}
1567	>	}
1568	>	} finally {
1569	>	t.release(0);
1570	>	}
1571	>	if (len != 0)
1572	>	break;
1573	>	}
1574	>	else
1575	>	tab = (Node<V>[])fk;
1576	>	}
1577	>	else {
1578	>	synchronized (f) {
1579	>	if (tabAt(tab, i) == f) {
1580	>	len = 1;
1581	>	for (Node<V> e = f, pred = null;; ++len) {
1582	>	Object ek; V ev;
1583	>	if (e.hash == h &&
1584	>	(ev = e.val) != null &&
1585	>	((ek = e.key) == k || k.equals(ek))) {
1586	>	val = mf.apply(ev, v);
1587	>	if (val != null)
1588	>	e.val = val;
1589	>	else {
1590	>	delta = -1;
1591	>	Node<V> en = e.next;
1592	>	if (pred != null)
1593	>	pred.next = en;
1594	>	else
1595	>	setTabAt(tab, i, en);
1596	>	}
1597	>	break;
1598	>	}
1599	>	pred = e;
1600	>	if ((e = e.next) == null) {
1601	>	val = v;
1602	>	pred.next = new Node<V>(h, k, val, null);
1603	>	delta = 1;
1604	>	if (len >= TREE_THRESHOLD)
1605	>	replaceWithTreeBin(tab, i, k);
1606	>	break;
1607	>	}
1608	>	}
1609	>	}
1610	>	}
1611	>	if (len != 0)
1612	>	break;
1613	>	}
1614	>	}
1615	>	if (delta != 0)
1616	>	addCount((long)delta, len);
1617	>	return val;
1618	>	}
1619
1620	+	/** Implementation for putAll */
1621	+	@SuppressWarnings("unchecked") private final void internalPutAll
1622	+	(Map<? extends K, ? extends V> m) {
1623	+	tryPresize(m.size());
1624	+	long delta = 0L;     // number of uncommitted additions
1625	+	boolean npe = false; // to throw exception on exit for nulls
1626	+	try {                // to clean up counts on other exceptions
1627	+	for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
1628	+	Object k; V v;
1629	+	if (entry == null || (k = entry.getKey()) == null ||
1630	+	(v = entry.getValue()) == null) {
1631	+	npe = true;
1632	+	break;
1633	+	}
1634	+	int h = spread(k.hashCode());
1635	+	for (Node<V>[] tab = table;;) {
1636	+	int i; Node<V> f; int fh; Object fk;
1637	+	if (tab == null)
1638	+	tab = initTable();
1639	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1640	+	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1641	+	++delta;
1642	+	break;
1643	+	}
1644	+	}
1645	+	else if ((fh = f.hash) < 0) {
1646	+	if ((fk = f.key) instanceof TreeBin) {
1647	+	TreeBin<V> t = (TreeBin<V>)fk;
1648	+	boolean validated = false;
1649	+	t.acquire(0);
1650	+	try {
1651	+	if (tabAt(tab, i) == f) {
1652	+	validated = true;
1653	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1654	+	if (p != null)
1655	+	p.val = v;
1656	+	else {
1657	+	t.putTreeNode(h, k, v);
1658	+	++delta;
1659	+	}
1660	+	}
1661	+	} finally {
1662	+	t.release(0);
1663	+	}
1664	+	if (validated)
1665	+	break;
1666	+	}
1667	+	else
1668	+	tab = (Node<V>[])fk;
1669	+	}
1670		else {
1671	<	// Reuse trailing consecutive sequence at same slot
1672	<	HashEntry<K,V> lastRun = e;
1673	<	int lastIdx = idx;
1674	<	for (HashEntry<K,V> last = next;
1675	<	last != null;
1676	<	last = last.next) {
1677	<	int k = last.hash & sizeMask;
1678	<	if (k != lastIdx) {
1679	<	lastIdx = k;
1680	<	lastRun = last;
1671	>	int len = 0;
1672	>	synchronized (f) {
1673	>	if (tabAt(tab, i) == f) {
1674	>	len = 1;
1675	>	for (Node<V> e = f;; ++len) {
1676	>	Object ek; V ev;
1677	>	if (e.hash == h &&
1678	>	(ev = e.val) != null &&
1679	>	((ek = e.key) == k || k.equals(ek))) {
1680	>	e.val = v;
1681	>	break;
1682	>	}
1683	>	Node<V> last = e;
1684	>	if ((e = e.next) == null) {
1685	>	++delta;
1686	>	last.next = new Node<V>(h, k, v, null);
1687	>	if (len >= TREE_THRESHOLD)
1688	>	replaceWithTreeBin(tab, i, k);
1689	>	break;
1690	>	}
1691	>	}
1692	>	}
1693	>	}
1694	>	if (len != 0) {
1695	>	if (len > 1) {
1696	>	addCount(delta, len);
1697	>	delta = 0L;
1698		}
1699	+	break;
1700		}
1701	<	newTable[lastIdx] = lastRun;
1701	>	}
1702	>	}
1703	>	}
1704	>	} finally {
1705	>	if (delta != 0L)
1706	>	addCount(delta, 2);
1707	>	}
1708	>	if (npe)
1709	>	throw new NullPointerException();
1710	>	}
1711
1712	<	// Clone all remaining nodes
1713	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1714	<	int k = p.hash & sizeMask;
1715	<	newTable[k] = new HashEntry<K,V>(p.hash,
1716	<	p.key,
1717	<	p.value,
1718	<	(HashEntry<K,V>) newTable[k]);
1712	>	/**
1713	>	* Implementation for clear. Steps through each bin, removing all
1714	>	* nodes.
1715	>	*/
1716	>	@SuppressWarnings("unchecked") private final void internalClear() {
1717	>	long delta = 0L; // negative number of deletions
1718	>	int i = 0;
1719	>	Node<V>[] tab = table;
1720	>	while (tab != null && i < tab.length) {
1721	>	Node<V> f = tabAt(tab, i);
1722	>	if (f == null)
1723	>	++i;
1724	>	else if (f.hash < 0) {
1725	>	Object fk;
1726	>	if ((fk = f.key) instanceof TreeBin) {
1727	>	TreeBin<V> t = (TreeBin<V>)fk;
1728	>	t.acquire(0);
1729	>	try {
1730	>	if (tabAt(tab, i) == f) {
1731	>	for (Node<V> p = t.first; p != null; p = p.next) {
1732	>	if (p.val != null) { // (currently always true)
1733	>	p.val = null;
1734	>	--delta;
1735	>	}
1736	>	}
1737	>	t.first = null;
1738	>	t.root = null;
1739	>	++i;
1740	>	}
1741	>	} finally {
1742	>	t.release(0);
1743	>	}
1744	>	}
1745	>	else
1746	>	tab = (Node<V>[])fk;
1747	>	}
1748	>	else {
1749	>	synchronized (f) {
1750	>	if (tabAt(tab, i) == f) {
1751	>	for (Node<V> e = f; e != null; e = e.next) {
1752	>	if (e.val != null) {  // (currently always true)
1753	>	e.val = null;
1754	>	--delta;
1755	>	}
1756		}
1757	+	setTabAt(tab, i, null);
1758	+	++i;
1759		}
1760		}
1761		}
379	–	return newTable;
1762		}
1763	+	if (delta != 0L)
1764	+	addCount(delta, -1);
1765	+	}
1766
1767	<	/**
383	<	* Remove; match on key only if value null, else match both.
384	<	*/
385	<	V remove(Object key, int hash, Object value) {
386	<	lock();
387	<	try {
388	<	int c = count;
389	<	HashEntry[] tab = table;
390	<	int index = hash & (tab.length - 1);
391	<	HashEntry<K,V> first = (HashEntry<K,V>)tab[index];
1767	>	/* ---------------- Table Initialization and Resizing -------------- */
1768
1769	<	HashEntry<K,V> e = first;
1770	<	for (;;) {
1771	<	if (e == null)
1772	<	return null;
1773	<	if (e.hash == hash && key.equals(e.key))
1769	>	/**
1770	>	* Returns a power of two table size for the given desired capacity.
1771	>	* See Hackers Delight, sec 3.2
1772	>	*/
1773	>	private static final int tableSizeFor(int c) {
1774	>	int n = c - 1;
1775	>	n |= n >>> 1;
1776	>	n |= n >>> 2;
1777	>	n |= n >>> 4;
1778	>	n |= n >>> 8;
1779	>	n |= n >>> 16;
1780	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1781	>	}
1782	>
1783	>	/**
1784	>	* Initializes table, using the size recorded in sizeCtl.
1785	>	*/
1786	>	@SuppressWarnings("unchecked") private final Node<V>[] initTable() {
1787	>	Node<V>[] tab; int sc;
1788	>	while ((tab = table) == null) {
1789	>	if ((sc = sizeCtl) < 0)
1790	>	Thread.yield(); // lost initialization race; just spin
1791	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1792	>	try {
1793	>	if ((tab = table) == null) {
1794	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1795	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1796	>	table = tab = (Node<V>[])tb;
1797	>	sc = n - (n >>> 2);
1798	>	}
1799	>	} finally {
1800	>	sizeCtl = sc;
1801	>	}
1802	>	break;
1803	>	}
1804	>	}
1805	>	return tab;
1806	>	}
1807	>
1808	>	/**
1809	>	* Adds to count, and if table is too small and not already
1810	>	* resizing, initiates transfer. If already resizing, helps
1811	>	* perform transfer if work is available.  Rechecks occupancy
1812	>	* after a transfer to see if another resize is already needed
1813	>	* because resizings are lagging additions.
1814	>	*
1815	>	* @param x the count to add
1816	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
1817	>	*/
1818	>	private final void addCount(long x, int check) {
1819	>	Cell[] as; long b, s;
1820	>	if ((as = counterCells) != null ||
1821	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
1822	>	Cell a; long v; int m;
1823	>	boolean uncontended = true;
1824	>	if (as == null || (m = as.length - 1) < 0 ||
1825	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
1826	>	!(uncontended =
1827	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
1828	>	fullAddCount(x, uncontended);
1829	>	return;
1830	>	}
1831	>	if (check <= 1)
1832	>	return;
1833	>	s = sumCount();
1834	>	}
1835	>	if (check >= 0) {
1836	>	Node<V>[] tab, nt; int sc;
1837	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
1838	>	tab.length < MAXIMUM_CAPACITY) {
1839	>	if (sc < 0) {
1840	>	if (sc == -1 || transferIndex <= transferOrigin ||
1841	>	(nt = nextTable) == null)
1842		break;
1843	<	e = e.next;
1843	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
1844	>	transfer(tab, nt);
1845		}
1846	+	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
1847	+	transfer(tab, null);
1848	+	s = sumCount();
1849	+	}
1850	+	}
1851	+	}
1852
1853	<	V oldValue = e.value;
1854	<	if (value != null && !value.equals(oldValue))
1855	<	return null;
1856	<
1857	<	// All entries following removed node can stay in list, but
1858	<	// all preceeding ones need to be cloned.
1859	<	HashEntry<K,V> newFirst = e.next;
1860	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
1861	<	newFirst = new HashEntry<K,V>(p.hash, p.key,
1862	<	p.value, newFirst);
1863	<	tab[index] = newFirst;
1864	<	++modCount;
1865	<	count = c-1; // write-volatile
1866	<	return oldValue;
1867	<	} finally {
1868	<	unlock();
1853	>	/**
1854	>	* Tries to presize table to accommodate the given number of elements.
1855	>	*
1856	>	* @param size number of elements (doesn't need to be perfectly accurate)
1857	>	*/
1858	>	@SuppressWarnings("unchecked") private final void tryPresize(int size) {
1859	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1860	>	tableSizeFor(size + (size >>> 1) + 1);
1861	>	int sc;
1862	>	while ((sc = sizeCtl) >= 0) {
1863	>	Node<V>[] tab = table; int n;
1864	>	if (tab == null || (n = tab.length) == 0) {
1865	>	n = (sc > c) ? sc : c;
1866	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1867	>	try {
1868	>	if (table == tab) {
1869	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1870	>	table = (Node<V>[])tb;
1871	>	sc = n - (n >>> 2);
1872	>	}
1873	>	} finally {
1874	>	sizeCtl = sc;
1875	>	}
1876	>	}
1877		}
1878	+	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1879	+	break;
1880	+	else if (tab == table &&
1881	+	U.compareAndSwapInt(this, SIZECTL, sc, -2))
1882	+	transfer(tab, null);
1883		}
1884	+	}
1885
1886	<	void clear() {
1887	<	lock();
1886	>	/**
1887	>	* Moves and/or copies the nodes in each bin to new table. See
1888	>	* above for explanation.
1889	>	*/
1890	>	@SuppressWarnings("unchecked") private final void transfer
1891	>	(Node<V>[] tab, Node<V>[] nextTab) {
1892	>	int n = tab.length, stride;
1893	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
1894	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
1895	>	if (nextTab == null) {            // initiating
1896		try {
1897	<	HashEntry[] tab = table;
1898	<	for (int i = 0; i < tab.length ; i++)
1899	<	tab[i] = null;
1900	<	++modCount;
1901	<	count = 0; // write-volatile
1902	<	} finally {
1903	<	unlock();
1897	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n << 1];
1898	>	nextTab = (Node<V>[])tb;
1899	>	} catch (Throwable ex) {      // try to cope with OOME
1900	>	sizeCtl = Integer.MAX_VALUE;
1901	>	return;
1902	>	}
1903	>	nextTable = nextTab;
1904	>	transferOrigin = n;
1905	>	transferIndex = n;
1906	>	Node<V> rev = new Node<V>(MOVED, tab, null, null);
1907	>	for (int k = n; k > 0;) {    // progressively reveal ready slots
1908	>	int nextk = (k > stride) ? k - stride : 0;
1909	>	for (int m = nextk; m < k; ++m)
1910	>	nextTab[m] = rev;
1911	>	for (int m = n + nextk; m < n + k; ++m)
1912	>	nextTab[m] = rev;
1913	>	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
1914	>	}
1915	>	}
1916	>	int nextn = nextTab.length;
1917	>	Node<V> fwd = new Node<V>(MOVED, nextTab, null, null);
1918	>	boolean advance = true;
1919	>	for (int i = 0, bound = 0;;) {
1920	>	int nextIndex, nextBound; Node<V> f; Object fk;
1921	>	while (advance) {
1922	>	if (--i >= bound)
1923	>	advance = false;
1924	>	else if ((nextIndex = transferIndex) <= transferOrigin) {
1925	>	i = -1;
1926	>	advance = false;
1927	>	}
1928	>	else if (U.compareAndSwapInt
1929	>	(this, TRANSFERINDEX, nextIndex,
1930	>	nextBound = (nextIndex > stride ?
1931	>	nextIndex - stride : 0))) {
1932	>	bound = nextBound;
1933	>	i = nextIndex - 1;
1934	>	advance = false;
1935	>	}
1936	>	}
1937	>	if (i < 0 || i >= n || i + n >= nextn) {
1938	>	for (int sc;;) {
1939	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
1940	>	if (sc == -1) {
1941	>	nextTable = null;
1942	>	table = nextTab;
1943	>	sizeCtl = (n << 1) - (n >>> 1);
1944	>	}
1945	>	return;
1946	>	}
1947	>	}
1948	>	}
1949	>	else if ((f = tabAt(tab, i)) == null) {
1950	>	if (casTabAt(tab, i, null, fwd)) {
1951	>	setTabAt(nextTab, i, null);
1952	>	setTabAt(nextTab, i + n, null);
1953	>	advance = true;
1954	>	}
1955	>	}
1956	>	else if (f.hash >= 0) {
1957	>	synchronized (f) {
1958	>	if (tabAt(tab, i) == f) {
1959	>	int runBit = f.hash & n;
1960	>	Node<V> lastRun = f, lo = null, hi = null;
1961	>	for (Node<V> p = f.next; p != null; p = p.next) {
1962	>	int b = p.hash & n;
1963	>	if (b != runBit) {
1964	>	runBit = b;
1965	>	lastRun = p;
1966	>	}
1967	>	}
1968	>	if (runBit == 0)
1969	>	lo = lastRun;
1970	>	else
1971	>	hi = lastRun;
1972	>	for (Node<V> p = f; p != lastRun; p = p.next) {
1973	>	int ph = p.hash;
1974	>	Object pk = p.key; V pv = p.val;
1975	>	if ((ph & n) == 0)
1976	>	lo = new Node<V>(ph, pk, pv, lo);
1977	>	else
1978	>	hi = new Node<V>(ph, pk, pv, hi);
1979	>	}
1980	>	setTabAt(nextTab, i, lo);
1981	>	setTabAt(nextTab, i + n, hi);
1982	>	setTabAt(tab, i, fwd);
1983	>	advance = true;
1984	>	}
1985	>	}
1986	>	}
1987	>	else if ((fk = f.key) instanceof TreeBin) {
1988	>	TreeBin<V> t = (TreeBin<V>)fk;
1989	>	t.acquire(0);
1990	>	try {
1991	>	if (tabAt(tab, i) == f) {
1992	>	TreeBin<V> lt = new TreeBin<V>();
1993	>	TreeBin<V> ht = new TreeBin<V>();
1994	>	int lc = 0, hc = 0;
1995	>	for (Node<V> e = t.first; e != null; e = e.next) {
1996	>	int h = e.hash;
1997	>	Object k = e.key; V v = e.val;
1998	>	if ((h & n) == 0) {
1999	>	++lc;
2000	>	lt.putTreeNode(h, k, v);
2001	>	}
2002	>	else {
2003	>	++hc;
2004	>	ht.putTreeNode(h, k, v);
2005	>	}
2006	>	}
2007	>	Node<V> ln, hn; // throw away trees if too small
2008	>	if (lc < TREE_THRESHOLD) {
2009	>	ln = null;
2010	>	for (Node<V> p = lt.first; p != null; p = p.next)
2011	>	ln = new Node<V>(p.hash, p.key, p.val, ln);
2012	>	}
2013	>	else
2014	>	ln = new Node<V>(MOVED, lt, null, null);
2015	>	setTabAt(nextTab, i, ln);
2016	>	if (hc < TREE_THRESHOLD) {
2017	>	hn = null;
2018	>	for (Node<V> p = ht.first; p != null; p = p.next)
2019	>	hn = new Node<V>(p.hash, p.key, p.val, hn);
2020	>	}
2021	>	else
2022	>	hn = new Node<V>(MOVED, ht, null, null);
2023	>	setTabAt(nextTab, i + n, hn);
2024	>	setTabAt(tab, i, fwd);
2025	>	advance = true;
2026	>	}
2027	>	} finally {
2028	>	t.release(0);
2029	>	}
2030	>	}
2031	>	else
2032	>	advance = true; // already processed
2033	>	}
2034	>	}
2035	>
2036	>	/* ---------------- Counter support -------------- */
2037	>
2038	>	final long sumCount() {
2039	>	Cell[] as = counterCells; Cell a;
2040	>	long sum = baseCount;
2041	>	if (as != null) {
2042	>	for (int i = 0; i < as.length; ++i) {
2043	>	if ((a = as[i]) != null)
2044	>	sum += a.value;
2045	>	}
2046	>	}
2047	>	return sum;
2048	>	}
2049	>
2050	>	// See LongAdder version for explanation
2051	>	private final void fullAddCount(long x, boolean wasUncontended) {
2052	>	int h;
2053	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2054	>	ThreadLocalRandom.localInit();      // force initialization
2055	>	h = ThreadLocalRandom.getProbe();
2056	>	wasUncontended = true;
2057	>	}
2058	>	boolean collide = false;                // True if last slot nonempty
2059	>	for (;;) {
2060	>	Cell[] as; Cell a; int n; long v;
2061	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2062	>	if ((a = as[(n - 1) & h]) == null) {
2063	>	if (cellsBusy == 0) {            // Try to attach new Cell
2064	>	Cell r = new Cell(x); // Optimistic create
2065	>	if (cellsBusy == 0 &&
2066	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2067	>	boolean created = false;
2068	>	try {               // Recheck under lock
2069	>	Cell[] rs; int m, j;
2070	>	if ((rs = counterCells) != null &&
2071	>	(m = rs.length) > 0 &&
2072	>	rs[j = (m - 1) & h] == null) {
2073	>	rs[j] = r;
2074	>	created = true;
2075	>	}
2076	>	} finally {
2077	>	cellsBusy = 0;
2078	>	}
2079	>	if (created)
2080	>	break;
2081	>	continue;           // Slot is now non-empty
2082	>	}
2083	>	}
2084	>	collide = false;
2085	>	}
2086	>	else if (!wasUncontended)       // CAS already known to fail
2087	>	wasUncontended = true;      // Continue after rehash
2088	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2089	>	break;
2090	>	else if (counterCells != as || n >= NCPU)
2091	>	collide = false;            // At max size or stale
2092	>	else if (!collide)
2093	>	collide = true;
2094	>	else if (cellsBusy == 0 &&
2095	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2096	>	try {
2097	>	if (counterCells == as) {// Expand table unless stale
2098	>	Cell[] rs = new Cell[n << 1];
2099	>	for (int i = 0; i < n; ++i)
2100	>	rs[i] = as[i];
2101	>	counterCells = rs;
2102	>	}
2103	>	} finally {
2104	>	cellsBusy = 0;
2105	>	}
2106	>	collide = false;
2107	>	continue;                   // Retry with expanded table
2108	>	}
2109	>	h = ThreadLocalRandom.advanceProbe(h);
2110	>	}
2111	>	else if (cellsBusy == 0 && counterCells == as &&
2112	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2113	>	boolean init = false;
2114	>	try {                           // Initialize table
2115	>	if (counterCells == as) {
2116	>	Cell[] rs = new Cell[2];
2117	>	rs[h & 1] = new Cell(x);
2118	>	counterCells = rs;
2119	>	init = true;
2120	>	}
2121	>	} finally {
2122	>	cellsBusy = 0;
2123	>	}
2124	>	if (init)
2125	>	break;
2126		}
2127	+	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2128	+	break;                          // Fall back on using base
2129		}
2130		}
2131
2132	+	/* ----------------Table Traversal -------------- */
2133	+
2134		/**
2135	<	* ConcurrentHashMap list entry.
2135	>	* Encapsulates traversal for methods such as containsValue; also
2136	>	* serves as a base class for other iterators and bulk tasks.
2137	>	*
2138	>	* At each step, the iterator snapshots the key ("nextKey") and
2139	>	* value ("nextVal") of a valid node (i.e., one that, at point of
2140	>	* snapshot, has a non-null user value). Because val fields can
2141	>	* change (including to null, indicating deletion), field nextVal
2142	>	* might not be accurate at point of use, but still maintains the
2143	>	* weak consistency property of holding a value that was once
2144	>	* valid. To support iterator.remove, the nextKey field is not
2145	>	* updated (nulled out) when the iterator cannot advance.
2146	>	*
2147	>	* Internal traversals directly access these fields, as in:
2148	>	* {@code while (it.advance() != null) { process(it.nextKey); }}
2149	>	*
2150	>	* Exported iterators must track whether the iterator has advanced
2151	>	* (in hasNext vs next) (by setting/checking/nulling field
2152	>	* nextVal), and then extract key, value, or key-value pairs as
2153	>	* return values of next().
2154	>	*
2155	>	* The iterator visits once each still-valid node that was
2156	>	* reachable upon iterator construction. It might miss some that
2157	>	* were added to a bin after the bin was visited, which is OK wrt
2158	>	* consistency guarantees. Maintaining this property in the face
2159	>	* of possible ongoing resizes requires a fair amount of
2160	>	* bookkeeping state that is difficult to optimize away amidst
2161	>	* volatile accesses.  Even so, traversal maintains reasonable
2162	>	* throughput.
2163	>	*
2164	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2165	>	* However, if the table has been resized, then all future steps
2166	>	* must traverse both the bin at the current index as well as at
2167	>	* (index + baseSize); and so on for further resizings. To
2168	>	* paranoically cope with potential sharing by users of iterators
2169	>	* across threads, iteration terminates if a bounds checks fails
2170	>	* for a table read.
2171	>	*
2172	>	* This class supports both Spliterator-based traversal and
2173	>	* CountedCompleter-based bulk tasks. The same "batch" field is
2174	>	* used, but in slightly different ways, in the two cases.  For
2175	>	* Spliterators, it is a saturating (at Integer.MAX_VALUE)
2176	>	* estimate of element coverage. For CHM tasks, it is a pre-scaled
2177	>	* size that halves down to zero for leaf tasks, that is only
2178	>	* computed upon execution of the task. (Tasks can be submitted to
2179	>	* any pool, of any size, so we don't know scale factors until
2180	>	* running.)
2181	>	*
2182	>	* This class extends CountedCompleter to streamline parallel
2183	>	* iteration in bulk operations. This adds only a few fields of
2184	>	* space overhead, which is small enough in cases where it is not
2185	>	* needed to not worry about it.  Because CountedCompleter is
2186	>	* Serializable, but iterators need not be, we need to add warning
2187	>	* suppressions.
2188		*/
2189	<	private static class HashEntry<K,V> implements Entry<K,V> {
2190	<	private final K key;
2191	<	private V value;
2192	<	private final int hash;
2193	<	private final HashEntry<K,V> next;
2189	>	@SuppressWarnings("serial") static class Traverser<K,V,R>
2190	>	extends CountedCompleter<R> {
2191	>	final ConcurrentHashMap<K, V> map;
2192	>	Node<V> next;        // the next entry to use
2193	>	K nextKey;           // cached key field of next
2194	>	V nextVal;           // cached val field of next
2195	>	Node<V>[] tab;       // current table; updated if resized
2196	>	int index;           // index of bin to use next
2197	>	int baseIndex;       // current index of initial table
2198	>	int baseLimit;       // index bound for initial table
2199	>	int baseSize;        // initial table size
2200	>	int batch;           // split control
2201	>	/** Creates iterator for all entries in the table. */
2202	>	Traverser(ConcurrentHashMap<K, V> map) {
2203	>	this.map = map;
2204	>	Node<V>[] t;
2205	>	if ((t = tab = map.table) != null)
2206	>	baseLimit = baseSize = t.length;
2207	>	}
2208	>
2209	>	/** Task constructor */
2210	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it, int batch) {
2211	>	super(it);
2212	>	this.map = map;
2213	>	this.batch = batch; // -1 if unknown
2214	>	if (it == null) {
2215	>	Node<V>[] t;
2216	>	if ((t = tab = map.table) != null)
2217	>	baseLimit = baseSize = t.length;
2218	>	}
2219	>	else { // split parent
2220	>	this.tab = it.tab;
2221	>	this.baseSize = it.baseSize;
2222	>	int hi = this.baseLimit = it.baseLimit;
2223	>	it.baseLimit = this.index = this.baseIndex =
2224	>	(hi + it.baseIndex + 1) >>> 1;
2225	>	}
2226	>	}
2227
2228	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
2229	<	this.value = value;
2230	<	this.hash = hash;
2231	<	this.key = key;
2232	<	this.next = next;
2228	>	/** Spliterator constructor */
2229	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it) {
2230	>	super(it);
2231	>	this.map = map;
2232	>	if (it == null) {
2233	>	Node<V>[] t;
2234	>	if ((t = tab = map.table) != null)
2235	>	baseLimit = baseSize = t.length;
2236	>	long n = map.sumCount();
2237	>	batch = ((n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2238	>	(int)n);
2239	>	}
2240	>	else {
2241	>	this.tab = it.tab;
2242	>	this.baseSize = it.baseSize;
2243	>	int hi = this.baseLimit = it.baseLimit;
2244	>	it.baseLimit = this.index = this.baseIndex =
2245	>	(hi + it.baseIndex + 1) >>> 1;
2246	>	this.batch = it.batch >>>= 1;
2247	>	}
2248		}
2249
2250	<	public K getKey() {
2251	<	return key;
2250	>	/**
2251	>	* Advances next; returns nextVal or null if terminated.
2252	>	* See above for explanation.
2253	>	*/
2254	>	@SuppressWarnings("unchecked") final V advance() {
2255	>	Node<V> e = next;
2256	>	V ev = null;
2257	>	outer: do {
2258	>	if (e != null)                  // advance past used/skipped node
2259	>	e = e.next;
2260	>	while (e == null) {             // get to next non-null bin
2261	>	ConcurrentHashMap<K, V> m;
2262	>	Node<V>[] t; int b, i, n; Object ek; //  must use locals
2263	>	if ((t = tab) != null)
2264	>	n = t.length;
2265	>	else if ((m = map) != null && (t = tab = m.table) != null)
2266	>	n = baseLimit = baseSize = t.length;
2267	>	else
2268	>	break outer;
2269	>	if ((b = baseIndex) >= baseLimit ||
2270	>	(i = index) < 0 || i >= n)
2271	>	break outer;
2272	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2273	>	if ((ek = e.key) instanceof TreeBin)
2274	>	e = ((TreeBin<V>)ek).first;
2275	>	else {
2276	>	tab = (Node<V>[])ek;
2277	>	continue;           // restarts due to null val
2278	>	}
2279	>	}                           // visit upper slots if present
2280	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2281	>	}
2282	>	nextKey = (K)e.key;
2283	>	} while ((ev = e.val) == null);    // skip deleted or special nodes
2284	>	next = e;
2285	>	return nextVal = ev;
2286		}
2287
2288	<	public V getValue() {
2289	<	return value;
2288	>	public final void remove() {
2289	>	K k = nextKey;
2290	>	if (k == null && (advance() == null || (k = nextKey) == null))
2291	>	throw new IllegalStateException();
2292	>	map.internalReplace(k, null, null);
2293		}
2294
2295	<	public V setValue(V newValue) {
2296	<	// We aren't required to, and don't provide any
461	<	// visibility barriers for setting value.
462	<	if (newValue == null)
463	<	throw new NullPointerException();
464	<	V oldValue = this.value;
465	<	this.value = newValue;
466	<	return oldValue;
2295	>	public final boolean hasNext() {
2296	>	return nextVal != null || advance() != null;
2297		}
2298
2299	<	public boolean equals(Object o) {
2300	<	if (!(o instanceof Entry))
2301	<	return false;
2302	<	Entry<K,V> e = (Entry<K,V>)o;
2303	<	return (key.equals(e.getKey()) && value.equals(e.getValue()));
2299	>	public final boolean hasMoreElements() { return hasNext(); }
2300	>
2301	>	public void compute() { } // default no-op CountedCompleter body
2302	>
2303	>	/**
2304	>	* Returns a batch value > 0 if this task should (and must) be
2305	>	* split, if so, adding to pending count, and in any case
2306	>	* updating batch value. The initial batch value is approx
2307	>	* exp2 of the number of times (minus one) to split task by
2308	>	* two before executing leaf action. This value is faster to
2309	>	* compute and more convenient to use as a guide to splitting
2310	>	* than is the depth, since it is used while dividing by two
2311	>	* anyway.
2312	>	*/
2313	>	final int preSplit() {
2314	>	int b;  ForkJoinPool pool;
2315	>	if ((b = batch) < 0) { // force initialization
2316	>	int sp = (((pool = getPool()) == null) ?
2317	>	ForkJoinPool.getCommonPoolParallelism() :
2318	>	pool.getParallelism()) << 3; // slack of 8
2319	>	long n = map.sumCount();
2320	>	b = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
2321	>	}
2322	>	b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
2323	>	if ((batch = b) > 0)
2324	>	addToPendingCount(1);
2325	>	return b;
2326		}
2327
2328	<	public int hashCode() {
2329	<	return  key.hashCode() ^ value.hashCode();
2328	>	// spliterator support
2329	>
2330	>	public boolean hasExactSize() {
2331	>	return false;
2332		}
2333
2334	<	public String toString() {
2335	<	return key + "=" + value;
2334	>	public boolean hasExactSplits() {
2335	>	return false;
2336		}
483	–	}
2337
2338	+	public long estimateSize() {
2339	+	return batch;
2340	+	}
2341	+	}
2342
2343		/* ---------------- Public operations -------------- */
2344
2345		/**
2346	<	* Constructs a new, empty map with the specified initial
2347	<	* capacity and the specified load factor.
2346	>	* Creates a new, empty map with the default initial table size (16).
2347	>	*/
2348	>	public ConcurrentHashMap() {
2349	>	}
2350	>
2351	>	/**
2352	>	* Creates a new, empty map with an initial table size
2353	>	* accommodating the specified number of elements without the need
2354	>	* to dynamically resize.
2355	>	*
2356	>	* @param initialCapacity The implementation performs internal
2357	>	* sizing to accommodate this many elements.
2358	>	* @throws IllegalArgumentException if the initial capacity of
2359	>	* elements is negative
2360	>	*/
2361	>	public ConcurrentHashMap(int initialCapacity) {
2362	>	if (initialCapacity < 0)
2363	>	throw new IllegalArgumentException();
2364	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2365	>	MAXIMUM_CAPACITY :
2366	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2367	>	this.sizeCtl = cap;
2368	>	}
2369	>
2370	>	/**
2371	>	* Creates a new map with the same mappings as the given map.
2372	>	*
2373	>	* @param m the map
2374	>	*/
2375	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2376	>	this.sizeCtl = DEFAULT_CAPACITY;
2377	>	internalPutAll(m);
2378	>	}
2379	>
2380	>	/**
2381	>	* Creates a new, empty map with an initial table size based on
2382	>	* the given number of elements ({@code initialCapacity}) and
2383	>	* initial table density ({@code loadFactor}).
2384	>	*
2385	>	* @param initialCapacity the initial capacity. The implementation
2386	>	* performs internal sizing to accommodate this many elements,
2387	>	* given the specified load factor.
2388	>	* @param loadFactor the load factor (table density) for
2389	>	* establishing the initial table size
2390	>	* @throws IllegalArgumentException if the initial capacity of
2391	>	* elements is negative or the load factor is nonpositive
2392	>	*
2393	>	* @since 1.6
2394	>	*/
2395	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2396	>	this(initialCapacity, loadFactor, 1);
2397	>	}
2398	>
2399	>	/**
2400	>	* Creates a new, empty map with an initial table size based on
2401	>	* the given number of elements ({@code initialCapacity}), table
2402	>	* density ({@code loadFactor}), and number of concurrently
2403	>	* updating threads ({@code concurrencyLevel}).
2404		*
2405		* @param initialCapacity the initial capacity. The implementation
2406	<	* performs internal sizing to accommodate this many elements.
2407	<	* @param loadFactor  the load factor threshold, used to control resizing.
2406	>	* performs internal sizing to accommodate this many elements,
2407	>	* given the specified load factor.
2408	>	* @param loadFactor the load factor (table density) for
2409	>	* establishing the initial table size
2410		* @param concurrencyLevel the estimated number of concurrently
2411	<	* updating threads. The implementation performs internal sizing
2412	<	* to try to accommodate this many threads.
2411	>	* updating threads. The implementation may use this value as
2412	>	* a sizing hint.
2413		* @throws IllegalArgumentException if the initial capacity is
2414		* negative or the load factor or concurrencyLevel are
2415	<	* nonpositive.
2415	>	* nonpositive
2416		*/
2417		public ConcurrentHashMap(int initialCapacity,
2418	<	float loadFactor, int concurrencyLevel) {
2419	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
2418	>	float loadFactor, int concurrencyLevel) {
2419	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2420		throw new IllegalArgumentException();
2421	+	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2422	+	initialCapacity = concurrencyLevel;   // as estimated threads
2423	+	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2424	+	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2425	+	MAXIMUM_CAPACITY : tableSizeFor((int)size);
2426	+	this.sizeCtl = cap;
2427	+	}
2428
2429	<	if (concurrencyLevel > MAX_SEGMENTS)
2430	<	concurrencyLevel = MAX_SEGMENTS;
2431	<
2432	<	// Find power-of-two sizes best matching arguments
2433	<	int sshift = 0;
2434	<	int ssize = 1;
2435	<	while (ssize < concurrencyLevel) {
2436	<	++sshift;
2437	<	ssize <<= 1;
516	<	}
517	<	segmentShift = 32 - sshift;
518	<	segmentMask = ssize - 1;
519	<	this.segments = new Segment[ssize];
520	<
521	<	if (initialCapacity > MAXIMUM_CAPACITY)
522	<	initialCapacity = MAXIMUM_CAPACITY;
523	<	int c = initialCapacity / ssize;
524	<	if (c * ssize < initialCapacity)
525	<	++c;
526	<	int cap = 1;
527	<	while (cap < c)
528	<	cap <<= 1;
529	<
530	<	for (int i = 0; i < this.segments.length; ++i)
531	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
2429	>	/**
2430	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2431	>	* from the given type to {@code Boolean.TRUE}.
2432	>	*
2433	>	* @return the new set
2434	>	*/
2435	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2436	>	return new KeySetView<K,Boolean>(new ConcurrentHashMap<K,Boolean>(),
2437	>	Boolean.TRUE);
2438		}
2439
2440		/**
2441	<	* Constructs a new, empty map with the specified initial
2442	<	* capacity,  and with default load factor and concurrencyLevel.
2441	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2442	>	* from the given type to {@code Boolean.TRUE}.
2443		*
2444		* @param initialCapacity The implementation performs internal
2445		* sizing to accommodate this many elements.
2446		* @throws IllegalArgumentException if the initial capacity of
2447	<	* elements is negative.
2447	>	* elements is negative
2448	>	* @return the new set
2449		*/
2450	<	public ConcurrentHashMap(int initialCapacity) {
2451	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2450	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2451	>	return new KeySetView<K,Boolean>
2452	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2453		}
2454
2455		/**
2456	<	* Constructs a new, empty map with a default initial capacity,
549	<	* load factor, and concurrencyLevel.
2456	>	* {@inheritDoc}
2457		*/
2458	<	public ConcurrentHashMap() {
2459	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2458	>	public boolean isEmpty() {
2459	>	return sumCount() <= 0L; // ignore transient negative values
2460		}
2461
2462		/**
2463	<	* Constructs a new map with the same mappings as the given map.  The
557	<	* map is created with a capacity of twice the number of mappings in
558	<	* the given map or 11 (whichever is greater), and a default load factor.
2463	>	* {@inheritDoc}
2464		*/
2465	<	public <A extends K, B extends V> ConcurrentHashMap(Map<A,B> t) {
2466	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
2467	<	11),
2468	<	DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2469	<	putAll(t);
2465	>	public int size() {
2466	>	long n = sumCount();
2467	>	return ((n < 0L) ? 0 :
2468	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2469	>	(int)n);
2470		}
2471
2472	<	// inherit Map javadoc
2473	<	public boolean isEmpty() {
2474	<	/*
2475	<	* We need to keep track of per-segment modCounts to avoid ABA
2476	<	* problems in which an element in one segment was added and
2477	<	* in another removed during traversal, in which case the
2478	<	* table was never actually empty at any point. Note the
2479	<	* similar use of modCounts in the size() and containsValue()
2480	<	* methods, which are the only other methods also susceptible
2481	<	* to ABA problems.
2482	<	*/
2483	<	int[] mc = new int[segments.length];
579	<	int mcsum = 0;
580	<	for (int i = 0; i < segments.length; ++i) {
581	<	if (segments[i].count != 0)
582	<	return false;
583	<	else
584	<	mcsum += mc[i] = segments[i].modCount;
585	<	}
586	<	// If mcsum happens to be zero, then we know we got a snapshot
587	<	// before any modifications at all were made.  This is
588	<	// probably common enough to bother tracking.
589	<	if (mcsum != 0) {
590	<	for (int i = 0; i < segments.length; ++i) {
591	<	if (segments[i].count != 0 ||
592	<	mc[i] != segments[i].modCount)
593	<	return false;
594	<	}
595	<	}
596	<	return true;
2472	>	/**
2473	>	* Returns the number of mappings. This method should be used
2474	>	* instead of {@link #size} because a ConcurrentHashMap may
2475	>	* contain more mappings than can be represented as an int. The
2476	>	* value returned is an estimate; the actual count may differ if
2477	>	* there are concurrent insertions or removals.
2478	>	*
2479	>	* @return the number of mappings
2480	>	*/
2481	>	public long mappingCount() {
2482	>	long n = sumCount();
2483	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2484		}
2485
2486	<	// inherit Map javadoc
2487	<	public int size() {
2488	<	int[] mc = new int[segments.length];
2489	<	for (;;) {
2490	<	long sum = 0;
2491	<	int mcsum = 0;
2492	<	for (int i = 0; i < segments.length; ++i) {
2493	<	sum += segments[i].count;
2494	<	mcsum += mc[i] = segments[i].modCount;
2495	<	}
2496	<	int check = 0;
2497	<	if (mcsum != 0) {
2498	<	for (int i = 0; i < segments.length; ++i) {
612	<	check += segments[i].count;
613	<	if (mc[i] != segments[i].modCount) {
614	<	check = -1; // force retry
615	<	break;
616	<	}
617	<	}
618	<	}
619	<	if (check == sum) {
620	<	if (sum > Integer.MAX_VALUE)
621	<	return Integer.MAX_VALUE;
622	<	else
623	<	return (int)sum;
624	<	}
625	<	}
2486	>	/**
2487	>	* Returns the value to which the specified key is mapped,
2488	>	* or {@code null} if this map contains no mapping for the key.
2489	>	*
2490	>	* <p>More formally, if this map contains a mapping from a key
2491	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
2492	>	* then this method returns {@code v}; otherwise it returns
2493	>	* {@code null}.  (There can be at most one such mapping.)
2494	>	*
2495	>	* @throws NullPointerException if the specified key is null
2496	>	*/
2497	>	public V get(Object key) {
2498	>	return internalGet(key);
2499		}
2500
628	–
2501		/**
2502	<	* Returns the value to which the specified key is mapped in this table.
2502	>	* Returns the value to which the specified key is mapped,
2503	>	* or the given defaultValue if this map contains no mapping for the key.
2504		*
2505	<	* @param   key   a key in the table.
2506	<	* @return  the value to which the key is mapped in this table;
2507	<	*          <tt>null</tt> if the key is not mapped to any value in
2508	<	*          this table.
2509	<	* @throws  NullPointerException  if the key is
637	<	*               <tt>null</tt>.
2505	>	* @param key the key
2506	>	* @param defaultValue the value to return if this map contains
2507	>	* no mapping for the given key
2508	>	* @return the mapping for the key, if present; else the defaultValue
2509	>	* @throws NullPointerException if the specified key is null
2510		*/
2511	<	public V get(Object key) {
2512	<	int hash = hash(key); // throws NullPointerException if key null
2513	<	return segmentFor(hash).get((K) key, hash);
2511	>	public V getValueOrDefault(Object key, V defaultValue) {
2512	>	V v;
2513	>	return (v = internalGet(key)) == null ? defaultValue : v;
2514		}
2515
2516		/**
2517		* Tests if the specified object is a key in this table.
2518		*
2519	<	* @param   key   possible key.
2520	<	* @return  <tt>true</tt> if and only if the specified object
2521	<	*          is a key in this table, as determined by the
2522	<	*          <tt>equals</tt> method; <tt>false</tt> otherwise.
2523	<	* @throws  NullPointerException  if the key is
652	<	*               <tt>null</tt>.
2519	>	* @param  key   possible key
2520	>	* @return {@code true} if and only if the specified object
2521	>	*         is a key in this table, as determined by the
2522	>	*         {@code equals} method; {@code false} otherwise
2523	>	* @throws NullPointerException if the specified key is null
2524		*/
2525		public boolean containsKey(Object key) {
2526	<	int hash = hash(key); // throws NullPointerException if key null
656	<	return segmentFor(hash).containsKey(key, hash);
2526	>	return internalGet(key) != null;
2527		}
2528
2529		/**
2530	<	* Returns <tt>true</tt> if this map maps one or more keys to the
2531	<	* specified value. Note: This method requires a full internal
2532	<	* traversal of the hash table, and so is much slower than
663	<	* method <tt>containsKey</tt>.
2530	>	* Returns {@code true} if this map maps one or more keys to the
2531	>	* specified value. Note: This method may require a full traversal
2532	>	* of the map, and is much slower than method {@code containsKey}.
2533		*
2534	<	* @param value value whose presence in this map is to be tested.
2535	<	* @return <tt>true</tt> if this map maps one or more keys to the
2536	<	* specified value.
2537	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
2534	>	* @param value value whose presence in this map is to be tested
2535	>	* @return {@code true} if this map maps one or more keys to the
2536	>	*         specified value
2537	>	* @throws NullPointerException if the specified value is null
2538		*/
2539		public boolean containsValue(Object value) {
2540		if (value == null)
2541		throw new NullPointerException();
2542	<
2543	<	int[] mc = new int[segments.length];
2544	<	for (;;) {
2545	<	int sum = 0;
2546	<	int mcsum = 0;
678	<	for (int i = 0; i < segments.length; ++i) {
679	<	int c = segments[i].count;
680	<	mcsum += mc[i] = segments[i].modCount;
681	<	if (segments[i].containsValue(value))
682	<	return true;
683	<	}
684	<	boolean cleanSweep = true;
685	<	if (mcsum != 0) {
686	<	for (int i = 0; i < segments.length; ++i) {
687	<	int c = segments[i].count;
688	<	if (mc[i] != segments[i].modCount) {
689	<	cleanSweep = false;
690	<	break;
691	<	}
692	<	}
693	<	}
694	<	if (cleanSweep)
695	<	return false;
2542	>	V v;
2543	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2544	>	while ((v = it.advance()) != null) {
2545	>	if (v == value || value.equals(v))
2546	>	return true;
2547		}
2548	+	return false;
2549		}
2550
2551		/**
2552		* Legacy method testing if some key maps into the specified value
2553		* in this table.  This method is identical in functionality to
2554	<	* {@link #containsValue}, and  exists solely to ensure
2554	>	* {@link #containsValue}, and exists solely to ensure
2555		* full compatibility with class {@link java.util.Hashtable},
2556		* which supported this method prior to introduction of the
2557		* Java Collections framework.
2558	<
2559	<	* @param      value   a value to search for.
2560	<	* @return     <tt>true</tt> if and only if some key maps to the
2561	<	*             <tt>value</tt> argument in this table as
2562	<	*             determined by the <tt>equals</tt> method;
2563	<	*             <tt>false</tt> otherwise.
2564	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
2558	>	*
2559	>	* @param  value a value to search for
2560	>	* @return {@code true} if and only if some key maps to the
2561	>	*         {@code value} argument in this table as
2562	>	*         determined by the {@code equals} method;
2563	>	*         {@code false} otherwise
2564	>	* @throws NullPointerException if the specified value is null
2565		*/
2566	<	public boolean contains(Object value) {
2566	>	@Deprecated public boolean contains(Object value) {
2567		return containsValue(value);
2568		}
2569
2570		/**
2571	<	* Maps the specified <tt>key</tt> to the specified
2572	<	* <tt>value</tt> in this table. Neither the key nor the
721	<	* value can be <tt>null</tt>. <p>
2571	>	* Maps the specified key to the specified value in this table.
2572	>	* Neither the key nor the value can be null.
2573		*
2574	<	* The value can be retrieved by calling the <tt>get</tt> method
2574	>	* <p>The value can be retrieved by calling the {@code get} method
2575		* with a key that is equal to the original key.
2576		*
2577	<	* @param      key     the table key.
2578	<	* @param      value   the value.
2579	<	* @return     the previous value of the specified key in this table,
2580	<	*             or <tt>null</tt> if it did not have one.
2581	<	* @throws  NullPointerException  if the key or value is
731	<	*               <tt>null</tt>.
2577	>	* @param key key with which the specified value is to be associated
2578	>	* @param value value to be associated with the specified key
2579	>	* @return the previous value associated with {@code key}, or
2580	>	*         {@code null} if there was no mapping for {@code key}
2581	>	* @throws NullPointerException if the specified key or value is null
2582		*/
2583		public V put(K key, V value) {
2584	<	if (value == null)
735	<	throw new NullPointerException();
736	<	int hash = hash(key);
737	<	return segmentFor(hash).put(key, hash, value, false);
2584	>	return internalPut(key, value, false);
2585		}
2586
2587		/**
2588	<	* If the specified key is not already associated
742	<	* with a value, associate it with the given value.
743	<	* This is equivalent to
744	<	* <pre>
745	<	*   if (!map.containsKey(key))
746	<	*      return map.put(key, value);
747	<	*   else
748	<	*      return map.get(key);
749	<	* </pre>
750	<	* Except that the action is performed atomically.
751	<	* @param key key with which the specified value is to be associated.
752	<	* @param value value to be associated with the specified key.
753	<	* @return previous value associated with specified key, or <tt>null</tt>
754	<	*         if there was no mapping for key.  A <tt>null</tt> return can
755	<	*         also indicate that the map previously associated <tt>null</tt>
756	<	*         with the specified key, if the implementation supports
757	<	*         <tt>null</tt> values.
758	<	*
759	<	* @throws UnsupportedOperationException if the <tt>put</tt> operation is
760	<	*            not supported by this map.
761	<	* @throws ClassCastException if the class of the specified key or value
762	<	*            prevents it from being stored in this map.
763	<	* @throws NullPointerException if the specified key or value is
764	<	*            <tt>null</tt>.
2588	>	* {@inheritDoc}
2589		*
2590	<	**/
2590	>	* @return the previous value associated with the specified key,
2591	>	*         or {@code null} if there was no mapping for the key
2592	>	* @throws NullPointerException if the specified key or value is null
2593	>	*/
2594		public V putIfAbsent(K key, V value) {
2595	<	if (value == null)
769	<	throw new NullPointerException();
770	<	int hash = hash(key);
771	<	return segmentFor(hash).put(key, hash, value, true);
2595	>	return internalPut(key, value, true);
2596		}
2597
774	–
2598		/**
2599		* Copies all of the mappings from the specified map to this one.
777	–	*
2600		* These mappings replace any mappings that this map had for any of the
2601	<	* keys currently in the specified Map.
2601	>	* keys currently in the specified map.
2602		*
2603	<	* @param t Mappings to be stored in this map.
2603	>	* @param m mappings to be stored in this map
2604		*/
2605	<	public void putAll(Map<? extends K, ? extends V> t) {
2606	<	for (Iterator<Map.Entry<? extends K, ? extends V>> it = (Iterator<Map.Entry<? extends K, ? extends V>>) t.entrySet().iterator(); it.hasNext(); ) {
785	<	Entry<? extends K, ? extends V> e = it.next();
786	<	put(e.getKey(), e.getValue());
787	<	}
2605	>	public void putAll(Map<? extends K, ? extends V> m) {
2606	>	internalPutAll(m);
2607		}
2608
2609		/**
2610	<	* Removes the key (and its corresponding value) from this
2611	<	* table. This method does nothing if the key is not in the table.
2610	>	* If the specified key is not already associated with a value (or
2611	>	* is mapped to {@code null}), attempts to compute its value using
2612	>	* the given mapping function and enters it into this map unless
2613	>	* {@code null}. The entire method invocation is performed
2614	>	* atomically, so the function is applied at most once per key.
2615	>	* Some attempted update operations on this map by other threads
2616	>	* may be blocked while computation is in progress, so the
2617	>	* computation should be short and simple, and must not attempt to
2618	>	* update any other mappings of this Map.
2619		*
2620	<	* @param   key   the key that needs to be removed.
2621	<	* @return  the value to which the key had been mapped in this table,
2622	<	*          or <tt>null</tt> if the key did not have a mapping.
2623	<	* @throws  NullPointerException  if the key is
2624	<	*               <tt>null</tt>.
2620	>	* @param key key with which the specified value is to be associated
2621	>	* @param mappingFunction the function to compute a value
2622	>	* @return the current (existing or computed) value associated with
2623	>	*         the specified key, or null if the computed value is null
2624	>	* @throws NullPointerException if the specified key or mappingFunction
2625	>	*         is null
2626	>	* @throws IllegalStateException if the computation detectably
2627	>	*         attempts a recursive update to this map that would
2628	>	*         otherwise never complete
2629	>	* @throws RuntimeException or Error if the mappingFunction does so,
2630	>	*         in which case the mapping is left unestablished
2631		*/
2632	<	public V remove(Object key) {
2633	<	int hash = hash(key);
2634	<	return segmentFor(hash).remove(key, hash, null);
2632	>	public V computeIfAbsent
2633	>	(K key, Function<? super K, ? extends V> mappingFunction) {
2634	>	return internalComputeIfAbsent(key, mappingFunction);
2635		}
2636
2637		/**
2638	<	* Remove entry for key only if currently mapped to given value.
2639	<	* Acts as
2640	<	* <pre>
2641	<	*  if (map.get(key).equals(value)) {
2642	<	*     map.remove(key);
2643	<	*     return true;
2644	<	* } else return false;
2645	<	* </pre>
2646	<	* except that the action is performed atomically.
2647	<	* @param key key with which the specified value is associated.
2648	<	* @param value value associated with the specified key.
2649	<	* @return true if the value was removed
2650	<	* @throws NullPointerException if the specified key is
2651	<	*            <tt>null</tt>.
2638	>	* If the value for the specified key is present and non-null,
2639	>	* attempts to compute a new mapping given the key and its current
2640	>	* mapped value.  The entire method invocation is performed
2641	>	* atomically.  Some attempted update operations on this map by
2642	>	* other threads may be blocked while computation is in progress,
2643	>	* so the computation should be short and simple, and must not
2644	>	* attempt to update any other mappings of this Map.
2645	>	*
2646	>	* @param key key with which the specified value is to be associated
2647	>	* @param remappingFunction the function to compute a value
2648	>	* @return the new value associated with the specified key, or null if none
2649	>	* @throws NullPointerException if the specified key or remappingFunction
2650	>	*         is null
2651	>	* @throws IllegalStateException if the computation detectably
2652	>	*         attempts a recursive update to this map that would
2653	>	*         otherwise never complete
2654	>	* @throws RuntimeException or Error if the remappingFunction does so,
2655	>	*         in which case the mapping is unchanged
2656		*/
2657	<	public boolean remove(Object key, Object value) {
2658	<	int hash = hash(key);
2659	<	return segmentFor(hash).remove(key, hash, value) != null;
2657	>	public V computeIfPresent
2658	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2659	>	return internalCompute(key, true, remappingFunction);
2660		}
2661
2662		/**
2663	<	* Removes all mappings from this map.
2663	>	* Attempts to compute a mapping for the specified key and its
2664	>	* current mapped value (or {@code null} if there is no current
2665	>	* mapping). The entire method invocation is performed atomically.
2666	>	* Some attempted update operations on this map by other threads
2667	>	* may be blocked while computation is in progress, so the
2668	>	* computation should be short and simple, and must not attempt to
2669	>	* update any other mappings of this Map.
2670	>	*
2671	>	* @param key key with which the specified value is to be associated
2672	>	* @param remappingFunction the function to compute a value
2673	>	* @return the new value associated with the specified key, or null if none
2674	>	* @throws NullPointerException if the specified key or remappingFunction
2675	>	*         is null
2676	>	* @throws IllegalStateException if the computation detectably
2677	>	*         attempts a recursive update to this map that would
2678	>	*         otherwise never complete
2679	>	* @throws RuntimeException or Error if the remappingFunction does so,
2680	>	*         in which case the mapping is unchanged
2681		*/
2682	<	public void clear() {
2683	<	for (int i = 0; i < segments.length; ++i)
2684	<	segments[i].clear();
2682	>	public V compute
2683	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2684	>	return internalCompute(key, false, remappingFunction);
2685		}
2686
2687	+	/**
2688	+	* If the specified key is not already associated with a
2689	+	* (non-null) value, associates it with the given value.
2690	+	* Otherwise, replaces the value with the results of the given
2691	+	* remapping function, or removes if {@code null}. The entire
2692	+	* method invocation is performed atomically.  Some attempted
2693	+	* update operations on this map by other threads may be blocked
2694	+	* while computation is in progress, so the computation should be
2695	+	* short and simple, and must not attempt to update any other
2696	+	* mappings of this Map.
2697	+	*
2698	+	* @param key key with which the specified value is to be associated
2699	+	* @param value the value to use if absent
2700	+	* @param remappingFunction the function to recompute a value if present
2701	+	* @return the new value associated with the specified key, or null if none
2702	+	* @throws NullPointerException if the specified key or the
2703	+	*         remappingFunction is null
2704	+	* @throws RuntimeException or Error if the remappingFunction does so,
2705	+	*         in which case the mapping is unchanged
2706	+	*/
2707	+	public V merge
2708	+	(K key, V value,
2709	+	BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2710	+	return internalMerge(key, value, remappingFunction);
2711	+	}
2712
2713		/**
2714	<	* Returns a shallow copy of this
2715	<	* <tt>ConcurrentHashMap</tt> instance: the keys and
838	<	* values themselves are not cloned.
2714	>	* Removes the key (and its corresponding value) from this map.
2715	>	* This method does nothing if the key is not in the map.
2716		*
2717	<	* @return a shallow copy of this map.
2717	>	* @param  key the key that needs to be removed
2718	>	* @return the previous value associated with {@code key}, or
2719	>	*         {@code null} if there was no mapping for {@code key}
2720	>	* @throws NullPointerException if the specified key is null
2721		*/
2722	<	public Object clone() {
2723	<	// We cannot call super.clone, since it would share final
2724	<	// segments array, and there's no way to reassign finals.
2722	>	public V remove(Object key) {
2723	>	return internalReplace(key, null, null);
2724	>	}
2725
2726	<	float lf = segments[0].loadFactor;
2727	<	int segs = segments.length;
2728	<	int cap = (int)(size() / lf);
2729	<	if (cap < segs) cap = segs;
2730	<	ConcurrentHashMap<K,V> t = new ConcurrentHashMap<K,V>(cap, lf, segs);
2731	<	t.putAll(this);
2732	<	return t;
2726	>	/**
2727	>	* {@inheritDoc}
2728	>	*
2729	>	* @throws NullPointerException if the specified key is null
2730	>	*/
2731	>	public boolean remove(Object key, Object value) {
2732	>	if (key == null)
2733	>	throw new NullPointerException();
2734	>	return value != null && internalReplace(key, null, value) != null;
2735		}
2736
2737		/**
2738	<	* Returns a set view of the keys contained in this map.  The set is
857	<	* backed by the map, so changes to the map are reflected in the set, and
858	<	* vice-versa.  The set supports element removal, which removes the
859	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
860	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
861	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
862	<	* <tt>addAll</tt> operations.
863	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
864	<	* will never throw {@link java.util.ConcurrentModificationException},
865	<	* and guarantees to traverse elements as they existed upon
866	<	* construction of the iterator, and may (but is not guaranteed to)
867	<	* reflect any modifications subsequent to construction.
2738	>	* {@inheritDoc}
2739		*
2740	<	* @return a set view of the keys contained in this map.
2740	>	* @throws NullPointerException if any of the arguments are null
2741		*/
2742	<	public Set<K> keySet() {
2743	<	Set<K> ks = keySet;
2744	<	return (ks != null) ? ks : (keySet = new KeySet());
2742	>	public boolean replace(K key, V oldValue, V newValue) {
2743	>	if (key == null || oldValue == null || newValue == null)
2744	>	throw new NullPointerException();
2745	>	return internalReplace(key, newValue, oldValue) != null;
2746		}
2747
2748	+	/**
2749	+	* {@inheritDoc}
2750	+	*
2751	+	* @return the previous value associated with the specified key,
2752	+	*         or {@code null} if there was no mapping for the key
2753	+	* @throws NullPointerException if the specified key or value is null
2754	+	*/
2755	+	public V replace(K key, V value) {
2756	+	if (key == null || value == null)
2757	+	throw new NullPointerException();
2758	+	return internalReplace(key, value, null);
2759	+	}
2760
2761		/**
2762	<	* Returns a collection view of the values contained in this map.  The
2763	<	* collection is backed by the map, so changes to the map are reflected in
2764	<	* the collection, and vice-versa.  The collection supports element
2765	<	* removal, which removes the corresponding mapping from this map, via the
2766	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
2767	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
2768	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
2769	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
2770	<	* will never throw {@link java.util.ConcurrentModificationException},
2771	<	* and guarantees to traverse elements as they existed upon
888	<	* construction of the iterator, and may (but is not guaranteed to)
889	<	* reflect any modifications subsequent to construction.
2762	>	* Removes all of the mappings from this map.
2763	>	*/
2764	>	public void clear() {
2765	>	internalClear();
2766	>	}
2767	>
2768	>	/**
2769	>	* Returns a {@link Set} view of the keys contained in this map.
2770	>	* The set is backed by the map, so changes to the map are
2771	>	* reflected in the set, and vice-versa.
2772		*
2773	<	* @return a collection view of the values contained in this map.
2773	>	* @return the set view
2774		*/
2775	<	public Collection<V> values() {
2776	<	Collection<V> vs = values;
2777	<	return (vs != null) ? vs : (values = new Values());
2775	>	public KeySetView<K,V> keySet() {
2776	>	KeySetView<K,V> ks = keySet;
2777	>	return (ks != null) ? ks : (keySet = new KeySetView<K,V>(this, null));
2778		}
2779
2780	+	/**
2781	+	* Returns a {@link Set} view of the keys in this map, using the
2782	+	* given common mapped value for any additions (i.e., {@link
2783	+	* Collection#add} and {@link Collection#addAll}). This is of
2784	+	* course only appropriate if it is acceptable to use the same
2785	+	* value for all additions from this view.
2786	+	*
2787	+	* @param mappedValue the mapped value to use for any
2788	+	* additions.
2789	+	* @return the set view
2790	+	* @throws NullPointerException if the mappedValue is null
2791	+	*/
2792	+	public KeySetView<K,V> keySet(V mappedValue) {
2793	+	if (mappedValue == null)
2794	+	throw new NullPointerException();
2795	+	return new KeySetView<K,V>(this, mappedValue);
2796	+	}
2797
2798		/**
2799	<	* Returns a collection view of the mappings contained in this map.  Each
2800	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
2801	<	* collection is backed by the map, so changes to the map are reflected in
2802	<	* the collection, and vice-versa.  The collection supports element
2803	<	* removal, which removes the corresponding mapping from the map, via the
2804	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
2805	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
2806	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
2807	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
2808	<	* will never throw {@link java.util.ConcurrentModificationException},
2799	>	* Returns a {@link Collection} view of the values contained in this map.
2800	>	* The collection is backed by the map, so changes to the map are
2801	>	* reflected in the collection, and vice-versa.
2802	>	*/
2803	>	public ValuesView<K,V> values() {
2804	>	ValuesView<K,V> vs = values;
2805	>	return (vs != null) ? vs : (values = new ValuesView<K,V>(this));
2806	>	}
2807	>
2808	>	/**
2809	>	* Returns a {@link Set} view of the mappings contained in this map.
2810	>	* The set is backed by the map, so changes to the map are
2811	>	* reflected in the set, and vice-versa.  The set supports element
2812	>	* removal, which removes the corresponding mapping from the map,
2813	>	* via the {@code Iterator.remove}, {@code Set.remove},
2814	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2815	>	* operations.  It does not support the {@code add} or
2816	>	* {@code addAll} operations.
2817	>	*
2818	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2819	>	* that will never throw {@link ConcurrentModificationException},
2820		* and guarantees to traverse elements as they existed upon
2821		* construction of the iterator, and may (but is not guaranteed to)
2822		* reflect any modifications subsequent to construction.
913	–	*
914	–	* @return a collection view of the mappings contained in this map.
2823		*/
2824		public Set<Map.Entry<K,V>> entrySet() {
2825	<	Set<Map.Entry<K,V>> es = entrySet;
2826	<	return (es != null) ? es : (entrySet = (Set<Map.Entry<K,V>>) (Set) new EntrySet());
2825	>	EntrySetView<K,V> es = entrySet;
2826	>	return (es != null) ? es : (entrySet = new EntrySetView<K,V>(this));
2827		}
2828
921	–
2829		/**
2830		* Returns an enumeration of the keys in this table.
2831		*
2832	<	* @return  an enumeration of the keys in this table.
2833	<	* @see     #keySet
2832	>	* @return an enumeration of the keys in this table
2833	>	* @see #keySet()
2834		*/
2835		public Enumeration<K> keys() {
2836	<	return new KeyIterator();
2836	>	return new KeyIterator<K,V>(this);
2837		}
2838
2839		/**
2840		* Returns an enumeration of the values in this table.
934	–	* Use the Enumeration methods on the returned object to fetch the elements
935	–	* sequentially.
2841		*
2842	<	* @return  an enumeration of the values in this table.
2843	<	* @see     #values
2842	>	* @return an enumeration of the values in this table
2843	>	* @see #values()
2844		*/
2845		public Enumeration<V> elements() {
2846	<	return new ValueIterator();
2846	>	return new ValueIterator<K,V>(this);
2847		}
2848
2849	<	/* ---------------- Iterator Support -------------- */
2849	>	/**
2850	>	* Returns the hash code value for this {@link Map}, i.e.,
2851	>	* the sum of, for each key-value pair in the map,
2852	>	* {@code key.hashCode() ^ value.hashCode()}.
2853	>	*
2854	>	* @return the hash code value for this map
2855	>	*/
2856	>	public int hashCode() {
2857	>	int h = 0;
2858	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2859	>	V v;
2860	>	while ((v = it.advance()) != null) {
2861	>	h += it.nextKey.hashCode() ^ v.hashCode();
2862	>	}
2863	>	return h;
2864	>	}
2865
2866	<	private abstract class HashIterator {
2867	<	private int nextSegmentIndex;
2868	<	private int nextTableIndex;
2869	<	private HashEntry[] currentTable;
2870	<	private HashEntry<K, V> nextEntry;
2871	<	private HashEntry<K, V> lastReturned;
2866	>	/**
2867	>	* Returns a string representation of this map.  The string
2868	>	* representation consists of a list of key-value mappings (in no
2869	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
2870	>	* mappings are separated by the characters {@code ", "} (comma
2871	>	* and space).  Each key-value mapping is rendered as the key
2872	>	* followed by an equals sign ("{@code =}") followed by the
2873	>	* associated value.
2874	>	*
2875	>	* @return a string representation of this map
2876	>	*/
2877	>	public String toString() {
2878	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2879	>	StringBuilder sb = new StringBuilder();
2880	>	sb.append('{');
2881	>	V v;
2882	>	if ((v = it.advance()) != null) {
2883	>	for (;;) {
2884	>	K k = it.nextKey;
2885	>	sb.append(k == this ? "(this Map)" : k);
2886	>	sb.append('=');
2887	>	sb.append(v == this ? "(this Map)" : v);
2888	>	if ((v = it.advance()) == null)
2889	>	break;
2890	>	sb.append(',').append(' ');
2891	>	}
2892	>	}
2893	>	return sb.append('}').toString();
2894	>	}
2895
2896	<	private HashIterator() {
2897	<	nextSegmentIndex = segments.length - 1;
2898	<	nextTableIndex = -1;
2899	<	advance();
2896	>	/**
2897	>	* Compares the specified object with this map for equality.
2898	>	* Returns {@code true} if the given object is a map with the same
2899	>	* mappings as this map.  This operation may return misleading
2900	>	* results if either map is concurrently modified during execution
2901	>	* of this method.
2902	>	*
2903	>	* @param o object to be compared for equality with this map
2904	>	* @return {@code true} if the specified object is equal to this map
2905	>	*/
2906	>	public boolean equals(Object o) {
2907	>	if (o != this) {
2908	>	if (!(o instanceof Map))
2909	>	return false;
2910	>	Map<?,?> m = (Map<?,?>) o;
2911	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2912	>	V val;
2913	>	while ((val = it.advance()) != null) {
2914	>	Object v = m.get(it.nextKey);
2915	>	if (v == null || (v != val && !v.equals(val)))
2916	>	return false;
2917	>	}
2918	>	for (Map.Entry<?,?> e : m.entrySet()) {
2919	>	Object mk, mv, v;
2920	>	if ((mk = e.getKey()) == null ||
2921	>	(mv = e.getValue()) == null ||
2922	>	(v = internalGet(mk)) == null ||
2923	>	(mv != v && !mv.equals(v)))
2924	>	return false;
2925	>	}
2926		}
2927	+	return true;
2928	+	}
2929
2930	<	public boolean hasMoreElements() { return hasNext(); }
2930	>	/* ----------------Iterators -------------- */
2931
2932	<	private void advance() {
2933	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
2934	<	return;
2932	>	@SuppressWarnings("serial") static final class KeyIterator<K,V>
2933	>	extends Traverser<K,V,Object>
2934	>	implements Spliterator<K>, Iterator<K>, Enumeration<K> {
2935	>	KeyIterator(ConcurrentHashMap<K, V> map) { super(map); }
2936	>	KeyIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
2937	>	super(map, it);
2938	>	}
2939	>	public KeyIterator<K,V> trySplit() {
2940	>	if (tab != null && baseIndex == baseLimit)
2941	>	return null;
2942	>	return new KeyIterator<K,V>(map, this);
2943	>	}
2944	>	public final K next() {
2945	>	if (nextVal == null && advance() == null)
2946	>	throw new NoSuchElementException();
2947	>	K k = nextKey;
2948	>	nextVal = null;
2949	>	return k;
2950	>	}
2951
2952	<	while (nextTableIndex >= 0) {
2953	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[nextTableIndex--]) != null)
2954	<	return;
2955	<	}
2952	>	public final K nextElement() { return next(); }
2953	>
2954	>	public Iterator<K> iterator() { return this; }
2955	>
2956	>	public void forEach(Block<? super K> action) {
2957	>	if (action == null) throw new NullPointerException();
2958	>	while (advance() != null)
2959	>	action.accept(nextKey);
2960	>	}
2961	>
2962	>	public boolean tryAdvance(Block<? super K> block) {
2963	>	if (block == null) throw new NullPointerException();
2964	>	if (advance() == null)
2965	>	return false;
2966	>	block.accept(nextKey);
2967	>	return true;
2968	>	}
2969	>	}
2970	>
2971	>	@SuppressWarnings("serial") static final class ValueIterator<K,V>
2972	>	extends Traverser<K,V,Object>
2973	>	implements Spliterator<V>, Iterator<V>, Enumeration<V> {
2974	>	ValueIterator(ConcurrentHashMap<K, V> map) { super(map); }
2975	>	ValueIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
2976	>	super(map, it);
2977	>	}
2978	>	public ValueIterator<K,V> trySplit() {
2979	>	if (tab != null && baseIndex == baseLimit)
2980	>	return null;
2981	>	return new ValueIterator<K,V>(map, this);
2982	>	}
2983	>
2984	>	public final V next() {
2985	>	V v;
2986	>	if ((v = nextVal) == null && (v = advance()) == null)
2987	>	throw new NoSuchElementException();
2988	>	nextVal = null;
2989	>	return v;
2990	>	}
2991	>
2992	>	public final V nextElement() { return next(); }
2993	>
2994	>	public Iterator<V> iterator() { return this; }
2995	>
2996	>	public void forEach(Block<? super V> action) {
2997	>	if (action == null) throw new NullPointerException();
2998	>	V v;
2999	>	while ((v = advance()) != null)
3000	>	action.accept(v);
3001	>	}
3002	>
3003	>	public boolean tryAdvance(Block<? super V> block) {
3004	>	V v;
3005	>	if (block == null) throw new NullPointerException();
3006	>	if ((v = advance()) == null)
3007	>	return false;
3008	>	block.accept(v);
3009	>	return true;
3010	>	}
3011	>
3012	>	}
3013	>
3014	>	@SuppressWarnings("serial") static final class EntryIterator<K,V>
3015	>	extends Traverser<K,V,Object>
3016	>	implements Spliterator<Map.Entry<K,V>>, Iterator<Map.Entry<K,V>> {
3017	>	EntryIterator(ConcurrentHashMap<K, V> map) { super(map); }
3018	>	EntryIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
3019	>	super(map, it);
3020	>	}
3021	>	public EntryIterator<K,V> trySplit() {
3022	>	if (tab != null && baseIndex == baseLimit)
3023	>	return null;
3024	>	return new EntryIterator<K,V>(map, this);
3025	>	}
3026	>
3027	>	public final Map.Entry<K,V> next() {
3028	>	V v;
3029	>	if ((v = nextVal) == null && (v = advance()) == null)
3030	>	throw new NoSuchElementException();
3031	>	K k = nextKey;
3032	>	nextVal = null;
3033	>	return new MapEntry<K,V>(k, v, map);
3034	>	}
3035	>
3036	>	public Iterator<Map.Entry<K,V>> iterator() { return this; }
3037	>
3038	>	public void forEach(Block<? super Map.Entry<K,V>> action) {
3039	>	if (action == null) throw new NullPointerException();
3040	>	V v;
3041	>	while ((v = advance()) != null)
3042	>	action.accept(entryFor(nextKey, v));
3043	>	}
3044	>
3045	>	public boolean tryAdvance(Block<? super Map.Entry<K,V>> block) {
3046	>	V v;
3047	>	if (block == null) throw new NullPointerException();
3048	>	if ((v = advance()) == null)
3049	>	return false;
3050	>	block.accept(entryFor(nextKey, v));
3051	>	return true;
3052	>	}
3053	>
3054	>	}
3055	>
3056	>	/**
3057	>	* Exported Entry for iterators
3058	>	*/
3059	>	static final class MapEntry<K,V> implements Map.Entry<K, V> {
3060	>	final K key; // non-null
3061	>	V val;       // non-null
3062	>	final ConcurrentHashMap<K, V> map;
3063	>	MapEntry(K key, V val, ConcurrentHashMap<K, V> map) {
3064	>	this.key = key;
3065	>	this.val = val;
3066	>	this.map = map;
3067	>	}
3068	>	public final K getKey()       { return key; }
3069	>	public final V getValue()     { return val; }
3070	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3071	>	public final String toString(){ return key + "=" + val; }
3072	>
3073	>	public final boolean equals(Object o) {
3074	>	Object k, v; Map.Entry<?,?> e;
3075	>	return ((o instanceof Map.Entry) &&
3076	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3077	>	(v = e.getValue()) != null &&
3078	>	(k == key || k.equals(key)) &&
3079	>	(v == val || v.equals(val)));
3080	>	}
3081	>
3082	>	/**
3083	>	* Sets our entry's value and writes through to the map. The
3084	>	* value to return is somewhat arbitrary here. Since we do not
3085	>	* necessarily track asynchronous changes, the most recent
3086	>	* "previous" value could be different from what we return (or
3087	>	* could even have been removed in which case the put will
3088	>	* re-establish). We do not and cannot guarantee more.
3089	>	*/
3090	>	public final V setValue(V value) {
3091	>	if (value == null) throw new NullPointerException();
3092	>	V v = val;
3093	>	val = value;
3094	>	map.put(key, value);
3095	>	return v;
3096	>	}
3097	>	}
3098	>
3099	>	/**
3100	>	* Returns exportable snapshot entry for the given key and value
3101	>	* when write-through can't or shouldn't be used.
3102	>	*/
3103	>	static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
3104	>	return new AbstractMap.SimpleEntry<K,V>(k, v);
3105	>	}
3106	>
3107	>	/* ---------------- Serialization Support -------------- */
3108	>
3109	>	/**
3110	>	* Stripped-down version of helper class used in previous version,
3111	>	* declared for the sake of serialization compatibility
3112	>	*/
3113	>	static class Segment<K,V> implements Serializable {
3114	>	private static final long serialVersionUID = 2249069246763182397L;
3115	>	final float loadFactor;
3116	>	Segment(float lf) { this.loadFactor = lf; }
3117	>	}
3118	>
3119	>	/**
3120	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
3121	>	* stream (i.e., serializes it).
3122	>	* @param s the stream
3123	>	* @serialData
3124	>	* the key (Object) and value (Object)
3125	>	* for each key-value mapping, followed by a null pair.
3126	>	* The key-value mappings are emitted in no particular order.
3127	>	*/
3128	>	@SuppressWarnings("unchecked") private void writeObject
3129	>	(java.io.ObjectOutputStream s)
3130	>	throws java.io.IOException {
3131	>	if (segments == null) { // for serialization compatibility
3132	>	segments = (Segment<K,V>[])
3133	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3134	>	for (int i = 0; i < segments.length; ++i)
3135	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3136	>	}
3137	>	s.defaultWriteObject();
3138	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3139	>	V v;
3140	>	while ((v = it.advance()) != null) {
3141	>	s.writeObject(it.nextKey);
3142	>	s.writeObject(v);
3143	>	}
3144	>	s.writeObject(null);
3145	>	s.writeObject(null);
3146	>	segments = null; // throw away
3147	>	}
3148	>
3149	>	/**
3150	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3151	>	* @param s the stream
3152	>	*/
3153	>	@SuppressWarnings("unchecked") private void readObject
3154	>	(java.io.ObjectInputStream s)
3155	>	throws java.io.IOException, ClassNotFoundException {
3156	>	s.defaultReadObject();
3157	>	this.segments = null; // unneeded
3158
3159	<	while (nextSegmentIndex >= 0) {
3160	<	Segment<K,V> seg = (Segment<K,V>)segments[nextSegmentIndex--];
3161	<	if (seg.count != 0) {
3162	<	currentTable = seg.table;
3163	<	for (int j = currentTable.length - 1; j >= 0; --j) {
3164	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[j]) != null) {
3165	<	nextTableIndex = j - 1;
3166	<	return;
3159	>	// Create all nodes, then place in table once size is known
3160	>	long size = 0L;
3161	>	Node<V> p = null;
3162	>	for (;;) {
3163	>	K k = (K) s.readObject();
3164	>	V v = (V) s.readObject();
3165	>	if (k != null && v != null) {
3166	>	int h = spread(k.hashCode());
3167	>	p = new Node<V>(h, k, v, p);
3168	>	++size;
3169	>	}
3170	>	else
3171	>	break;
3172	>	}
3173	>	if (p != null) {
3174	>	boolean init = false;
3175	>	int n;
3176	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3177	>	n = MAXIMUM_CAPACITY;
3178	>	else {
3179	>	int sz = (int)size;
3180	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3181	>	}
3182	>	int sc = sizeCtl;
3183	>	boolean collide = false;
3184	>	if (n > sc &&
3185	>	U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
3186	>	try {
3187	>	if (table == null) {
3188	>	init = true;
3189	>	@SuppressWarnings("rawtypes") Node[] rt = new Node[n];
3190	>	Node<V>[] tab = (Node<V>[])rt;
3191	>	int mask = n - 1;
3192	>	while (p != null) {
3193	>	int j = p.hash & mask;
3194	>	Node<V> next = p.next;
3195	>	Node<V> q = p.next = tabAt(tab, j);
3196	>	setTabAt(tab, j, p);
3197	>	if (!collide && q != null && q.hash == p.hash)
3198	>	collide = true;
3199	>	p = next;
3200	>	}
3201	>	table = tab;
3202	>	addCount(size, -1);
3203	>	sc = n - (n >>> 2);
3204	>	}
3205	>	} finally {
3206	>	sizeCtl = sc;
3207	>	}
3208	>	if (collide) { // rescan and convert to TreeBins
3209	>	Node<V>[] tab = table;
3210	>	for (int i = 0; i < tab.length; ++i) {
3211	>	int c = 0;
3212	>	for (Node<V> e = tabAt(tab, i); e != null; e = e.next) {
3213	>	if (++c > TREE_THRESHOLD &&
3214	>	(e.key instanceof Comparable)) {
3215	>	replaceWithTreeBin(tab, i, e.key);
3216	>	break;
3217	>	}
3218		}
3219		}
3220		}
3221		}
3222	+	if (!init) { // Can only happen if unsafely published.
3223	+	while (p != null) {
3224	+	internalPut((K)p.key, p.val, false);
3225	+	p = p.next;
3226	+	}
3227	+	}
3228		}
3229	+	}
3230
3231	<	public boolean hasNext() { return nextEntry != null; }
3231	>	// -------------------------------------------------------
3232
3233	<	HashEntry<K,V> nextEntry() {
3234	<	if (nextEntry == null)
3235	<	throw new NoSuchElementException();
3236	<	lastReturned = nextEntry;
3237	<	advance();
3238	<	return lastReturned;
3233	>	// Sequential bulk operations
3234	>
3235	>	/**
3236	>	* Performs the given action for each (key, value).
3237	>	*
3238	>	* @param action the action
3239	>	*/
3240	>	public void forEachSequentially
3241	>	(BiBlock<? super K, ? super V> action) {
3242	>	if (action == null) throw new NullPointerException();
3243	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3244	>	V v;
3245	>	while ((v = it.advance()) != null)
3246	>	action.accept(it.nextKey, v);
3247	>	}
3248	>
3249	>	/**
3250	>	* Performs the given action for each non-null transformation
3251	>	* of each (key, value).
3252	>	*
3253	>	* @param transformer a function returning the transformation
3254	>	* for an element, or null if there is no transformation (in
3255	>	* which case the action is not applied).
3256	>	* @param action the action
3257	>	*/
3258	>	public <U> void forEachSequentially
3259	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3260	>	Block<? super U> action) {
3261	>	if (transformer == null || action == null)
3262	>	throw new NullPointerException();
3263	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3264	>	V v; U u;
3265	>	while ((v = it.advance()) != null) {
3266	>	if ((u = transformer.apply(it.nextKey, v)) != null)
3267	>	action.accept(u);
3268		}
3269	+	}
3270
3271	<	public void remove() {
3272	<	if (lastReturned == null)
3273	<	throw new IllegalStateException();
3274	<	ConcurrentHashMap.this.remove(lastReturned.key);
3275	<	lastReturned = null;
3271	>	/**
3272	>	* Returns a non-null result from applying the given search
3273	>	* function on each (key, value), or null if none.
3274	>	*
3275	>	* @param searchFunction a function returning a non-null
3276	>	* result on success, else null
3277	>	* @return a non-null result from applying the given search
3278	>	* function on each (key, value), or null if none
3279	>	*/
3280	>	public <U> U searchSequentially
3281	>	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3282	>	if (searchFunction == null) throw new NullPointerException();
3283	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3284	>	V v; U u;
3285	>	while ((v = it.advance()) != null) {
3286	>	if ((u = searchFunction.apply(it.nextKey, v)) != null)
3287	>	return u;
3288		}
3289	+	return null;
3290		}
3291
3292	<	private class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
3293	<	public K next() { return super.nextEntry().key; }
3294	<	public K nextElement() { return super.nextEntry().key; }
3292	>	/**
3293	>	* Returns the result of accumulating the given transformation
3294	>	* of all (key, value) pairs using the given reducer to
3295	>	* combine values, or null if none.
3296	>	*
3297	>	* @param transformer a function returning the transformation
3298	>	* for an element, or null if there is no transformation (in
3299	>	* which case it is not combined).
3300	>	* @param reducer a commutative associative combining function
3301	>	* @return the result of accumulating the given transformation
3302	>	* of all (key, value) pairs
3303	>	*/
3304	>	public <U> U reduceSequentially
3305	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3306	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3307	>	if (transformer == null || reducer == null)
3308	>	throw new NullPointerException();
3309	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3310	>	U r = null, u; V v;
3311	>	while ((v = it.advance()) != null) {
3312	>	if ((u = transformer.apply(it.nextKey, v)) != null)
3313	>	r = (r == null) ? u : reducer.apply(r, u);
3314	>	}
3315	>	return r;
3316		}
3317
3318	<	private class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
3319	<	public V next() { return super.nextEntry().value; }
3320	<	public V nextElement() { return super.nextEntry().value; }
3318	>	/**
3319	>	* Returns the result of accumulating the given transformation
3320	>	* of all (key, value) pairs using the given reducer to
3321	>	* combine values, and the given basis as an identity value.
3322	>	*
3323	>	* @param transformer a function returning the transformation
3324	>	* for an element
3325	>	* @param basis the identity (initial default value) for the reduction
3326	>	* @param reducer a commutative associative combining function
3327	>	* @return the result of accumulating the given transformation
3328	>	* of all (key, value) pairs
3329	>	*/
3330	>	public double reduceToDoubleSequentially
3331	>	(DoubleBiFunction<? super K, ? super V> transformer,
3332	>	double basis,
3333	>	DoubleBinaryOperator reducer) {
3334	>	if (transformer == null || reducer == null)
3335	>	throw new NullPointerException();
3336	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3337	>	double r = basis; V v;
3338	>	while ((v = it.advance()) != null)
3339	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(it.nextKey, v));
3340	>	return r;
3341		}
3342
3343	<	private class EntryIterator extends HashIterator implements Iterator<Entry<K,V>> {
3344	<	public Map.Entry<K,V> next() { return super.nextEntry(); }
3343	>	/**
3344	>	* Returns the result of accumulating the given transformation
3345	>	* of all (key, value) pairs using the given reducer to
3346	>	* combine values, and the given basis as an identity value.
3347	>	*
3348	>	* @param transformer a function returning the transformation
3349	>	* for an element
3350	>	* @param basis the identity (initial default value) for the reduction
3351	>	* @param reducer a commutative associative combining function
3352	>	* @return the result of accumulating the given transformation
3353	>	* of all (key, value) pairs
3354	>	*/
3355	>	public long reduceToLongSequentially
3356	>	(LongBiFunction<? super K, ? super V> transformer,
3357	>	long basis,
3358	>	LongBinaryOperator reducer) {
3359	>	if (transformer == null || reducer == null)
3360	>	throw new NullPointerException();
3361	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3362	>	long r = basis; V v;
3363	>	while ((v = it.advance()) != null)
3364	>	r = reducer.applyAsLong(r, transformer.applyAsLong(it.nextKey, v));
3365	>	return r;
3366	>	}
3367	>
3368	>	/**
3369	>	* Returns the result of accumulating the given transformation
3370	>	* of all (key, value) pairs using the given reducer to
3371	>	* combine values, and the given basis as an identity value.
3372	>	*
3373	>	* @param transformer a function returning the transformation
3374	>	* for an element
3375	>	* @param basis the identity (initial default value) for the reduction
3376	>	* @param reducer a commutative associative combining function
3377	>	* @return the result of accumulating the given transformation
3378	>	* of all (key, value) pairs
3379	>	*/
3380	>	public int reduceToIntSequentially
3381	>	(IntBiFunction<? super K, ? super V> transformer,
3382	>	int basis,
3383	>	IntBinaryOperator reducer) {
3384	>	if (transformer == null || reducer == null)
3385	>	throw new NullPointerException();
3386	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3387	>	int r = basis; V v;
3388	>	while ((v = it.advance()) != null)
3389	>	r = reducer.applyAsInt(r, transformer.applyAsInt(it.nextKey, v));
3390	>	return r;
3391	>	}
3392	>
3393	>	/**
3394	>	* Performs the given action for each key.
3395	>	*
3396	>	* @param action the action
3397	>	*/
3398	>	public void forEachKeySequentially
3399	>	(Block<? super K> action) {
3400	>	if (action == null) throw new NullPointerException();
3401	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3402	>	while (it.advance() != null)
3403	>	action.accept(it.nextKey);
3404	>	}
3405	>
3406	>	/**
3407	>	* Performs the given action for each non-null transformation
3408	>	* of each key.
3409	>	*
3410	>	* @param transformer a function returning the transformation
3411	>	* for an element, or null if there is no transformation (in
3412	>	* which case the action is not applied).
3413	>	* @param action the action
3414	>	*/
3415	>	public <U> void forEachKeySequentially
3416	>	(Function<? super K, ? extends U> transformer,
3417	>	Block<? super U> action) {
3418	>	if (transformer == null || action == null)
3419	>	throw new NullPointerException();
3420	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3421	>	U u;
3422	>	while (it.advance() != null) {
3423	>	if ((u = transformer.apply(it.nextKey)) != null)
3424	>	action.accept(u);
3425	>	}
3426	>	ForkJoinTasks.forEachKey
3427	>	(this, transformer, action).invoke();
3428	>	}
3429	>
3430	>	/**
3431	>	* Returns a non-null result from applying the given search
3432	>	* function on each key, or null if none.
3433	>	*
3434	>	* @param searchFunction a function returning a non-null
3435	>	* result on success, else null
3436	>	* @return a non-null result from applying the given search
3437	>	* function on each key, or null if none
3438	>	*/
3439	>	public <U> U searchKeysSequentially
3440	>	(Function<? super K, ? extends U> searchFunction) {
3441	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3442	>	U u;
3443	>	while (it.advance() != null) {
3444	>	if ((u = searchFunction.apply(it.nextKey)) != null)
3445	>	return u;
3446	>	}
3447	>	return null;
3448		}
3449
3450	<	private class KeySet extends AbstractSet<K> {
3451	<	public Iterator<K> iterator() {
3452	<	return new KeyIterator();
3450	>	/**
3451	>	* Returns the result of accumulating all keys using the given
3452	>	* reducer to combine values, or null if none.
3453	>	*
3454	>	* @param reducer a commutative associative combining function
3455	>	* @return the result of accumulating all keys using the given
3456	>	* reducer to combine values, or null if none
3457	>	*/
3458	>	public K reduceKeysSequentially
3459	>	(BiFunction<? super K, ? super K, ? extends K> reducer) {
3460	>	if (reducer == null) throw new NullPointerException();
3461	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3462	>	K r = null;
3463	>	while (it.advance() != null) {
3464	>	K u = it.nextKey;
3465	>	r = (r == null) ? u : reducer.apply(r, u);
3466		}
3467	<	public int size() {
3468	<	return ConcurrentHashMap.this.size();
3467	>	return r;
3468	>	}
3469	>
3470	>	/**
3471	>	* Returns the result of accumulating the given transformation
3472	>	* of all keys using the given reducer to combine values, or
3473	>	* null if none.
3474	>	*
3475	>	* @param transformer a function returning the transformation
3476	>	* for an element, or null if there is no transformation (in
3477	>	* which case it is not combined).
3478	>	* @param reducer a commutative associative combining function
3479	>	* @return the result of accumulating the given transformation
3480	>	* of all keys
3481	>	*/
3482	>	public <U> U reduceKeysSequentially
3483	>	(Function<? super K, ? extends U> transformer,
3484	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3485	>	if (transformer == null || reducer == null)
3486	>	throw new NullPointerException();
3487	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3488	>	U r = null, u;
3489	>	while (it.advance() != null) {
3490	>	if ((u = transformer.apply(it.nextKey)) != null)
3491	>	r = (r == null) ? u : reducer.apply(r, u);
3492		}
3493	<	public boolean contains(Object o) {
3494	<	return ConcurrentHashMap.this.containsKey(o);
3493	>	return r;
3494	>	}
3495	>
3496	>	/**
3497	>	* Returns the result of accumulating the given transformation
3498	>	* of all keys using the given reducer to combine values, and
3499	>	* the given basis as an identity value.
3500	>	*
3501	>	* @param transformer a function returning the transformation
3502	>	* for an element
3503	>	* @param basis the identity (initial default value) for the reduction
3504	>	* @param reducer a commutative associative combining function
3505	>	* @return the result of accumulating the given transformation
3506	>	* of all keys
3507	>	*/
3508	>	public double reduceKeysToDoubleSequentially
3509	>	(DoubleFunction<? super K> transformer,
3510	>	double basis,
3511	>	DoubleBinaryOperator reducer) {
3512	>	if (transformer == null || reducer == null)
3513	>	throw new NullPointerException();
3514	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3515	>	double r = basis;
3516	>	while (it.advance() != null)
3517	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(it.nextKey));
3518	>	return r;
3519	>	}
3520	>
3521	>	/**
3522	>	* Returns the result of accumulating the given transformation
3523	>	* of all keys using the given reducer to combine values, and
3524	>	* the given basis as an identity value.
3525	>	*
3526	>	* @param transformer a function returning the transformation
3527	>	* for an element
3528	>	* @param basis the identity (initial default value) for the reduction
3529	>	* @param reducer a commutative associative combining function
3530	>	* @return the result of accumulating the given transformation
3531	>	* of all keys
3532	>	*/
3533	>	public long reduceKeysToLongSequentially
3534	>	(LongFunction<? super K> transformer,
3535	>	long basis,
3536	>	LongBinaryOperator reducer) {
3537	>	if (transformer == null || reducer == null)
3538	>	throw new NullPointerException();
3539	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3540	>	long r = basis;
3541	>	while (it.advance() != null)
3542	>	r = reducer.applyAsLong(r, transformer.applyAsLong(it.nextKey));
3543	>	return r;
3544	>	}
3545	>
3546	>	/**
3547	>	* Returns the result of accumulating the given transformation
3548	>	* of all keys using the given reducer to combine values, and
3549	>	* the given basis as an identity value.
3550	>	*
3551	>	* @param transformer a function returning the transformation
3552	>	* for an element
3553	>	* @param basis the identity (initial default value) for the reduction
3554	>	* @param reducer a commutative associative combining function
3555	>	* @return the result of accumulating the given transformation
3556	>	* of all keys
3557	>	*/
3558	>	public int reduceKeysToIntSequentially
3559	>	(IntFunction<? super K> transformer,
3560	>	int basis,
3561	>	IntBinaryOperator reducer) {
3562	>	if (transformer == null || reducer == null)
3563	>	throw new NullPointerException();
3564	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3565	>	int r = basis;
3566	>	while (it.advance() != null)
3567	>	r = reducer.applyAsInt(r, transformer.applyAsInt(it.nextKey));
3568	>	return r;
3569	>	}
3570	>
3571	>	/**
3572	>	* Performs the given action for each value.
3573	>	*
3574	>	* @param action the action
3575	>	*/
3576	>	public void forEachValueSequentially(Block<? super V> action) {
3577	>	if (action == null) throw new NullPointerException();
3578	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3579	>	V v;
3580	>	while ((v = it.advance()) != null)
3581	>	action.accept(v);
3582	>	}
3583	>
3584	>	/**
3585	>	* Performs the given action for each non-null transformation
3586	>	* of each value.
3587	>	*
3588	>	* @param transformer a function returning the transformation
3589	>	* for an element, or null if there is no transformation (in
3590	>	* which case the action is not applied).
3591	>	*/
3592	>	public <U> void forEachValueSequentially
3593	>	(Function<? super V, ? extends U> transformer,
3594	>	Block<? super U> action) {
3595	>	if (transformer == null || action == null)
3596	>	throw new NullPointerException();
3597	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3598	>	V v; U u;
3599	>	while ((v = it.advance()) != null) {
3600	>	if ((u = transformer.apply(v)) != null)
3601	>	action.accept(u);
3602		}
3603	<	public boolean remove(Object o) {
3604	<	return ConcurrentHashMap.this.remove(o) != null;
3603	>	}
3604	>
3605	>	/**
3606	>	* Returns a non-null result from applying the given search
3607	>	* function on each value, or null if none.
3608	>	*
3609	>	* @param searchFunction a function returning a non-null
3610	>	* result on success, else null
3611	>	* @return a non-null result from applying the given search
3612	>	* function on each value, or null if none
3613	>	*/
3614	>	public <U> U searchValuesSequentially
3615	>	(Function<? super V, ? extends U> searchFunction) {
3616	>	if (searchFunction == null) throw new NullPointerException();
3617	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3618	>	V v; U u;
3619	>	while ((v = it.advance()) != null) {
3620	>	if ((u = searchFunction.apply(v)) != null)
3621	>	return u;
3622		}
3623	<	public void clear() {
3624	<	ConcurrentHashMap.this.clear();
3623	>	return null;
3624	>	}
3625	>
3626	>	/**
3627	>	* Returns the result of accumulating all values using the
3628	>	* given reducer to combine values, or null if none.
3629	>	*
3630	>	* @param reducer a commutative associative combining function
3631	>	* @return the result of accumulating all values
3632	>	*/
3633	>	public V reduceValuesSequentially
3634	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
3635	>	if (reducer == null) throw new NullPointerException();
3636	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3637	>	V r = null; V v;
3638	>	while ((v = it.advance()) != null)
3639	>	r = (r == null) ? v : reducer.apply(r, v);
3640	>	return r;
3641	>	}
3642	>
3643	>	/**
3644	>	* Returns the result of accumulating the given transformation
3645	>	* of all values using the given reducer to combine values, or
3646	>	* null if none.
3647	>	*
3648	>	* @param transformer a function returning the transformation
3649	>	* for an element, or null if there is no transformation (in
3650	>	* which case it is not combined).
3651	>	* @param reducer a commutative associative combining function
3652	>	* @return the result of accumulating the given transformation
3653	>	* of all values
3654	>	*/
3655	>	public <U> U reduceValuesSequentially
3656	>	(Function<? super V, ? extends U> transformer,
3657	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3658	>	if (transformer == null || reducer == null)
3659	>	throw new NullPointerException();
3660	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3661	>	U r = null, u; V v;
3662	>	while ((v = it.advance()) != null) {
3663	>	if ((u = transformer.apply(v)) != null)
3664	>	r = (r == null) ? u : reducer.apply(r, u);
3665		}
3666	+	return r;
3667	+	}
3668	+
3669	+	/**
3670	+	* Returns the result of accumulating the given transformation
3671	+	* of all values using the given reducer to combine values,
3672	+	* and the given basis as an identity value.
3673	+	*
3674	+	* @param transformer a function returning the transformation
3675	+	* for an element
3676	+	* @param basis the identity (initial default value) for the reduction
3677	+	* @param reducer a commutative associative combining function
3678	+	* @return the result of accumulating the given transformation
3679	+	* of all values
3680	+	*/
3681	+	public double reduceValuesToDoubleSequentially
3682	+	(DoubleFunction<? super V> transformer,
3683	+	double basis,
3684	+	DoubleBinaryOperator reducer) {
3685	+	if (transformer == null || reducer == null)
3686	+	throw new NullPointerException();
3687	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3688	+	double r = basis; V v;
3689	+	while ((v = it.advance()) != null)
3690	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
3691	+	return r;
3692	+	}
3693	+
3694	+	/**
3695	+	* Returns the result of accumulating the given transformation
3696	+	* of all values using the given reducer to combine values,
3697	+	* and the given basis as an identity value.
3698	+	*
3699	+	* @param transformer a function returning the transformation
3700	+	* for an element
3701	+	* @param basis the identity (initial default value) for the reduction
3702	+	* @param reducer a commutative associative combining function
3703	+	* @return the result of accumulating the given transformation
3704	+	* of all values
3705	+	*/
3706	+	public long reduceValuesToLongSequentially
3707	+	(LongFunction<? super V> transformer,
3708	+	long basis,
3709	+	LongBinaryOperator reducer) {
3710	+	if (transformer == null || reducer == null)
3711	+	throw new NullPointerException();
3712	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3713	+	long r = basis; V v;
3714	+	while ((v = it.advance()) != null)
3715	+	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
3716	+	return r;
3717		}
3718
3719	<	private class Values extends AbstractCollection<V> {
3720	<	public Iterator<V> iterator() {
3721	<	return new ValueIterator();
3719	>	/**
3720	>	* Returns the result of accumulating the given transformation
3721	>	* of all values using the given reducer to combine values,
3722	>	* and the given basis as an identity value.
3723	>	*
3724	>	* @param transformer a function returning the transformation
3725	>	* for an element
3726	>	* @param basis the identity (initial default value) for the reduction
3727	>	* @param reducer a commutative associative combining function
3728	>	* @return the result of accumulating the given transformation
3729	>	* of all values
3730	>	*/
3731	>	public int reduceValuesToIntSequentially
3732	>	(IntFunction<? super V> transformer,
3733	>	int basis,
3734	>	IntBinaryOperator reducer) {
3735	>	if (transformer == null || reducer == null)
3736	>	throw new NullPointerException();
3737	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3738	>	int r = basis; V v;
3739	>	while ((v = it.advance()) != null)
3740	>	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
3741	>	return r;
3742	>	}
3743	>
3744	>	/**
3745	>	* Performs the given action for each entry.
3746	>	*
3747	>	* @param action the action
3748	>	*/
3749	>	public void forEachEntrySequentially
3750	>	(Block<? super Map.Entry<K,V>> action) {
3751	>	if (action == null) throw new NullPointerException();
3752	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3753	>	V v;
3754	>	while ((v = it.advance()) != null)
3755	>	action.accept(entryFor(it.nextKey, v));
3756	>	}
3757	>
3758	>	/**
3759	>	* Performs the given action for each non-null transformation
3760	>	* of each entry.
3761	>	*
3762	>	* @param transformer a function returning the transformation
3763	>	* for an element, or null if there is no transformation (in
3764	>	* which case the action is not applied).
3765	>	* @param action the action
3766	>	*/
3767	>	public <U> void forEachEntrySequentially
3768	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3769	>	Block<? super U> action) {
3770	>	if (transformer == null || action == null)
3771	>	throw new NullPointerException();
3772	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3773	>	V v; U u;
3774	>	while ((v = it.advance()) != null) {
3775	>	if ((u = transformer.apply(entryFor(it.nextKey, v))) != null)
3776	>	action.accept(u);
3777		}
3778	<	public int size() {
3779	<	return ConcurrentHashMap.this.size();
3778	>	}
3779	>
3780	>	/**
3781	>	* Returns a non-null result from applying the given search
3782	>	* function on each entry, or null if none.
3783	>	*
3784	>	* @param searchFunction a function returning a non-null
3785	>	* result on success, else null
3786	>	* @return a non-null result from applying the given search
3787	>	* function on each entry, or null if none
3788	>	*/
3789	>	public <U> U searchEntriesSequentially
3790	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
3791	>	if (searchFunction == null) throw new NullPointerException();
3792	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3793	>	V v; U u;
3794	>	while ((v = it.advance()) != null) {
3795	>	if ((u = searchFunction.apply(entryFor(it.nextKey, v))) != null)
3796	>	return u;
3797		}
3798	<	public boolean contains(Object o) {
3799	<	return ConcurrentHashMap.this.containsValue(o);
3798	>	return null;
3799	>	}
3800	>
3801	>	/**
3802	>	* Returns the result of accumulating all entries using the
3803	>	* given reducer to combine values, or null if none.
3804	>	*
3805	>	* @param reducer a commutative associative combining function
3806	>	* @return the result of accumulating all entries
3807	>	*/
3808	>	public Map.Entry<K,V> reduceEntriesSequentially
3809	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3810	>	if (reducer == null) throw new NullPointerException();
3811	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3812	>	Map.Entry<K,V> r = null; V v;
3813	>	while ((v = it.advance()) != null) {
3814	>	Map.Entry<K,V> u = entryFor(it.nextKey, v);
3815	>	r = (r == null) ? u : reducer.apply(r, u);
3816		}
3817	<	public void clear() {
3818	<	ConcurrentHashMap.this.clear();
3817	>	return r;
3818	>	}
3819	>
3820	>	/**
3821	>	* Returns the result of accumulating the given transformation
3822	>	* of all entries using the given reducer to combine values,
3823	>	* or null if none.
3824	>	*
3825	>	* @param transformer a function returning the transformation
3826	>	* for an element, or null if there is no transformation (in
3827	>	* which case it is not combined).
3828	>	* @param reducer a commutative associative combining function
3829	>	* @return the result of accumulating the given transformation
3830	>	* of all entries
3831	>	*/
3832	>	public <U> U reduceEntriesSequentially
3833	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3834	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3835	>	if (transformer == null || reducer == null)
3836	>	throw new NullPointerException();
3837	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3838	>	U r = null, u; V v;
3839	>	while ((v = it.advance()) != null) {
3840	>	if ((u = transformer.apply(entryFor(it.nextKey, v))) != null)
3841	>	r = (r == null) ? u : reducer.apply(r, u);
3842		}
3843	+	return r;
3844	+	}
3845	+
3846	+	/**
3847	+	* Returns the result of accumulating the given transformation
3848	+	* of all entries using the given reducer to combine values,
3849	+	* and the given basis as an identity value.
3850	+	*
3851	+	* @param transformer a function returning the transformation
3852	+	* for an element
3853	+	* @param basis the identity (initial default value) for the reduction
3854	+	* @param reducer a commutative associative combining function
3855	+	* @return the result of accumulating the given transformation
3856	+	* of all entries
3857	+	*/
3858	+	public double reduceEntriesToDoubleSequentially
3859	+	(DoubleFunction<Map.Entry<K,V>> transformer,
3860	+	double basis,
3861	+	DoubleBinaryOperator reducer) {
3862	+	if (transformer == null || reducer == null)
3863	+	throw new NullPointerException();
3864	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3865	+	double r = basis; V v;
3866	+	while ((v = it.advance()) != null)
3867	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor(it.nextKey, v)));
3868	+	return r;
3869	+	}
3870	+
3871	+	/**
3872	+	* Returns the result of accumulating the given transformation
3873	+	* of all entries using the given reducer to combine values,
3874	+	* and the given basis as an identity value.
3875	+	*
3876	+	* @param transformer a function returning the transformation
3877	+	* for an element
3878	+	* @param basis the identity (initial default value) for the reduction
3879	+	* @param reducer a commutative associative combining function
3880	+	* @return the result of accumulating the given transformation
3881	+	* of all entries
3882	+	*/
3883	+	public long reduceEntriesToLongSequentially
3884	+	(LongFunction<Map.Entry<K,V>> transformer,
3885	+	long basis,
3886	+	LongBinaryOperator reducer) {
3887	+	if (transformer == null || reducer == null)
3888	+	throw new NullPointerException();
3889	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3890	+	long r = basis; V v;
3891	+	while ((v = it.advance()) != null)
3892	+	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor(it.nextKey, v)));
3893	+	return r;
3894	+	}
3895	+
3896	+	/**
3897	+	* Returns the result of accumulating the given transformation
3898	+	* of all entries using the given reducer to combine values,
3899	+	* and the given basis as an identity value.
3900	+	*
3901	+	* @param transformer a function returning the transformation
3902	+	* for an element
3903	+	* @param basis the identity (initial default value) for the reduction
3904	+	* @param reducer a commutative associative combining function
3905	+	* @return the result of accumulating the given transformation
3906	+	* of all entries
3907	+	*/
3908	+	public int reduceEntriesToIntSequentially
3909	+	(IntFunction<Map.Entry<K,V>> transformer,
3910	+	int basis,
3911	+	IntBinaryOperator reducer) {
3912	+	if (transformer == null || reducer == null)
3913	+	throw new NullPointerException();
3914	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3915	+	int r = basis; V v;
3916	+	while ((v = it.advance()) != null)
3917	+	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor(it.nextKey, v)));
3918	+	return r;
3919	+	}
3920	+
3921	+	// Parallel bulk operations
3922	+
3923	+	/**
3924	+	* Performs the given action for each (key, value).
3925	+	*
3926	+	* @param action the action
3927	+	*/
3928	+	public void forEachInParallel(BiBlock<? super K,? super V> action) {
3929	+	ForkJoinTasks.forEach
3930	+	(this, action).invoke();
3931	+	}
3932	+
3933	+	/**
3934	+	* Performs the given action for each non-null transformation
3935	+	* of each (key, value).
3936	+	*
3937	+	* @param transformer a function returning the transformation
3938	+	* for an element, or null if there is no transformation (in
3939	+	* which case the action is not applied).
3940	+	* @param action the action
3941	+	*/
3942	+	public <U> void forEachInParallel
3943	+	(BiFunction<? super K, ? super V, ? extends U> transformer,
3944	+	Block<? super U> action) {
3945	+	ForkJoinTasks.forEach
3946	+	(this, transformer, action).invoke();
3947	+	}
3948	+
3949	+	/**
3950	+	* Returns a non-null result from applying the given search
3951	+	* function on each (key, value), or null if none.  Upon
3952	+	* success, further element processing is suppressed and the
3953	+	* results of any other parallel invocations of the search
3954	+	* function are ignored.
3955	+	*
3956	+	* @param searchFunction a function returning a non-null
3957	+	* result on success, else null
3958	+	* @return a non-null result from applying the given search
3959	+	* function on each (key, value), or null if none
3960	+	*/
3961	+	public <U> U searchInParallel
3962	+	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3963	+	return ForkJoinTasks.search
3964	+	(this, searchFunction).invoke();
3965	+	}
3966	+
3967	+	/**
3968	+	* Returns the result of accumulating the given transformation
3969	+	* of all (key, value) pairs using the given reducer to
3970	+	* combine values, or null if none.
3971	+	*
3972	+	* @param transformer a function returning the transformation
3973	+	* for an element, or null if there is no transformation (in
3974	+	* which case it is not combined).
3975	+	* @param reducer a commutative associative combining function
3976	+	* @return the result of accumulating the given transformation
3977	+	* of all (key, value) pairs
3978	+	*/
3979	+	public <U> U reduceInParallel
3980	+	(BiFunction<? super K, ? super V, ? extends U> transformer,
3981	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
3982	+	return ForkJoinTasks.reduce
3983	+	(this, transformer, reducer).invoke();
3984	+	}
3985	+
3986	+	/**
3987	+	* Returns the result of accumulating the given transformation
3988	+	* of all (key, value) pairs using the given reducer to
3989	+	* combine values, and the given basis as an identity value.
3990	+	*
3991	+	* @param transformer a function returning the transformation
3992	+	* for an element
3993	+	* @param basis the identity (initial default value) for the reduction
3994	+	* @param reducer a commutative associative combining function
3995	+	* @return the result of accumulating the given transformation
3996	+	* of all (key, value) pairs
3997	+	*/
3998	+	public double reduceToDoubleInParallel
3999	+	(DoubleBiFunction<? super K, ? super V> transformer,
4000	+	double basis,
4001	+	DoubleBinaryOperator reducer) {
4002	+	return ForkJoinTasks.reduceToDouble
4003	+	(this, transformer, basis, reducer).invoke();
4004	+	}
4005	+
4006	+	/**
4007	+	* Returns the result of accumulating the given transformation
4008	+	* of all (key, value) pairs using the given reducer to
4009	+	* combine values, and the given basis as an identity value.
4010	+	*
4011	+	* @param transformer a function returning the transformation
4012	+	* for an element
4013	+	* @param basis the identity (initial default value) for the reduction
4014	+	* @param reducer a commutative associative combining function
4015	+	* @return the result of accumulating the given transformation
4016	+	* of all (key, value) pairs
4017	+	*/
4018	+	public long reduceToLongInParallel
4019	+	(LongBiFunction<? super K, ? super V> transformer,
4020	+	long basis,
4021	+	LongBinaryOperator reducer) {
4022	+	return ForkJoinTasks.reduceToLong
4023	+	(this, transformer, basis, reducer).invoke();
4024	+	}
4025	+
4026	+	/**
4027	+	* Returns the result of accumulating the given transformation
4028	+	* of all (key, value) pairs using the given reducer to
4029	+	* combine values, and the given basis as an identity value.
4030	+	*
4031	+	* @param transformer a function returning the transformation
4032	+	* for an element
4033	+	* @param basis the identity (initial default value) for the reduction
4034	+	* @param reducer a commutative associative combining function
4035	+	* @return the result of accumulating the given transformation
4036	+	* of all (key, value) pairs
4037	+	*/
4038	+	public int reduceToIntInParallel
4039	+	(IntBiFunction<? super K, ? super V> transformer,
4040	+	int basis,
4041	+	IntBinaryOperator reducer) {
4042	+	return ForkJoinTasks.reduceToInt
4043	+	(this, transformer, basis, reducer).invoke();
4044	+	}
4045	+
4046	+	/**
4047	+	* Performs the given action for each key.
4048	+	*
4049	+	* @param action the action
4050	+	*/
4051	+	public void forEachKeyInParallel(Block<? super K> action) {
4052	+	ForkJoinTasks.forEachKey
4053	+	(this, action).invoke();
4054	+	}
4055	+
4056	+	/**
4057	+	* Performs the given action for each non-null transformation
4058	+	* of each key.
4059	+	*
4060	+	* @param transformer a function returning the transformation
4061	+	* for an element, or null if there is no transformation (in
4062	+	* which case the action is not applied).
4063	+	* @param action the action
4064	+	*/
4065	+	public <U> void forEachKeyInParallel
4066	+	(Function<? super K, ? extends U> transformer,
4067	+	Block<? super U> action) {
4068	+	ForkJoinTasks.forEachKey
4069	+	(this, transformer, action).invoke();
4070	+	}
4071	+
4072	+	/**
4073	+	* Returns a non-null result from applying the given search
4074	+	* function on each key, or null if none. Upon success,
4075	+	* further element processing is suppressed and the results of
4076	+	* any other parallel invocations of the search function are
4077	+	* 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, or null if none
4083	+	*/
4084	+	public <U> U searchKeysInParallel
4085	+	(Function<? super K, ? extends U> searchFunction) {
4086	+	return ForkJoinTasks.searchKeys
4087	+	(this, searchFunction).invoke();
4088	+	}
4089	+
4090	+	/**
4091	+	* Returns the result of accumulating all keys using the given
4092	+	* reducer to combine values, or null if none.
4093	+	*
4094	+	* @param reducer a commutative associative combining function
4095	+	* @return the result of accumulating all keys using the given
4096	+	* reducer to combine values, or null if none
4097	+	*/
4098	+	public K reduceKeysInParallel
4099	+	(BiFunction<? super K, ? super K, ? extends K> reducer) {
4100	+	return ForkJoinTasks.reduceKeys
4101	+	(this, reducer).invoke();
4102	+	}
4103	+
4104	+	/**
4105	+	* Returns the result of accumulating the given transformation
4106	+	* of all keys using the given reducer to combine values, or
4107	+	* null if none.
4108	+	*
4109	+	* @param transformer a function returning the transformation
4110	+	* for an element, or null if there is no transformation (in
4111	+	* which case it is not combined).
4112	+	* @param reducer a commutative associative combining function
4113	+	* @return the result of accumulating the given transformation
4114	+	* of all keys
4115	+	*/
4116	+	public <U> U reduceKeysInParallel
4117	+	(Function<? super K, ? extends U> transformer,
4118	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4119	+	return ForkJoinTasks.reduceKeys
4120	+	(this, transformer, reducer).invoke();
4121	+	}
4122	+
4123	+	/**
4124	+	* Returns the result of accumulating the given transformation
4125	+	* of all keys using the given reducer to combine values, and
4126	+	* the given basis as an identity value.
4127	+	*
4128	+	* @param transformer a function returning the transformation
4129	+	* for an element
4130	+	* @param basis the identity (initial default value) for the reduction
4131	+	* @param reducer a commutative associative combining function
4132	+	* @return the result of accumulating the given transformation
4133	+	* of all keys
4134	+	*/
4135	+	public double reduceKeysToDoubleInParallel
4136	+	(DoubleFunction<? super K> transformer,
4137	+	double basis,
4138	+	DoubleBinaryOperator reducer) {
4139	+	return ForkJoinTasks.reduceKeysToDouble
4140	+	(this, transformer, basis, reducer).invoke();
4141	+	}
4142	+
4143	+	/**
4144	+	* Returns the result of accumulating the given transformation
4145	+	* of all keys using the given reducer to combine values, and
4146	+	* the given basis as an identity value.
4147	+	*
4148	+	* @param transformer a function returning the transformation
4149	+	* for an element
4150	+	* @param basis the identity (initial default value) for the reduction
4151	+	* @param reducer a commutative associative combining function
4152	+	* @return the result of accumulating the given transformation
4153	+	* of all keys
4154	+	*/
4155	+	public long reduceKeysToLongInParallel
4156	+	(LongFunction<? super K> transformer,
4157	+	long basis,
4158	+	LongBinaryOperator reducer) {
4159	+	return ForkJoinTasks.reduceKeysToLong
4160	+	(this, transformer, basis, reducer).invoke();
4161	+	}
4162	+
4163	+	/**
4164	+	* Returns the result of accumulating the given transformation
4165	+	* of all keys using the given reducer to combine values, and
4166	+	* the given basis as an identity value.
4167	+	*
4168	+	* @param transformer a function returning the transformation
4169	+	* for an element
4170	+	* @param basis the identity (initial default value) for the reduction
4171	+	* @param reducer a commutative associative combining function
4172	+	* @return the result of accumulating the given transformation
4173	+	* of all keys
4174	+	*/
4175	+	public int reduceKeysToIntInParallel
4176	+	(IntFunction<? super K> transformer,
4177	+	int basis,
4178	+	IntBinaryOperator reducer) {
4179	+	return ForkJoinTasks.reduceKeysToInt
4180	+	(this, transformer, basis, reducer).invoke();
4181	+	}
4182	+
4183	+	/**
4184	+	* Performs the given action for each value.
4185	+	*
4186	+	* @param action the action
4187	+	*/
4188	+	public void forEachValueInParallel(Block<? super V> action) {
4189	+	ForkJoinTasks.forEachValue
4190	+	(this, action).invoke();
4191	+	}
4192	+
4193	+	/**
4194	+	* Performs the given action for each non-null transformation
4195	+	* of each value.
4196	+	*
4197	+	* @param transformer a function returning the transformation
4198	+	* for an element, or null if there is no transformation (in
4199	+	* which case the action is not applied).
4200	+	*/
4201	+	public <U> void forEachValueInParallel
4202	+	(Function<? super V, ? extends U> transformer,
4203	+	Block<? super U> action) {
4204	+	ForkJoinTasks.forEachValue
4205	+	(this, transformer, action).invoke();
4206	+	}
4207	+
4208	+	/**
4209	+	* Returns a non-null result from applying the given search
4210	+	* function on each value, or null if none.  Upon success,
4211	+	* further element processing is suppressed and the results of
4212	+	* any other parallel invocations of the search function are
4213	+	* ignored.
4214	+	*
4215	+	* @param searchFunction a function returning a non-null
4216	+	* result on success, else null
4217	+	* @return a non-null result from applying the given search
4218	+	* function on each value, or null if none
4219	+	*/
4220	+	public <U> U searchValuesInParallel
4221	+	(Function<? super V, ? extends U> searchFunction) {
4222	+	return ForkJoinTasks.searchValues
4223	+	(this, searchFunction).invoke();
4224		}
4225
4226	<	private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4227	<	public Iterator<Map.Entry<K,V>> iterator() {
4228	<	return new EntryIterator();
4226	>	/**
4227	>	* Returns the result of accumulating all values using the
4228	>	* given reducer to combine values, or null if none.
4229	>	*
4230	>	* @param reducer a commutative associative combining function
4231	>	* @return the result of accumulating all values
4232	>	*/
4233	>	public V reduceValuesInParallel
4234	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
4235	>	return ForkJoinTasks.reduceValues
4236	>	(this, reducer).invoke();
4237	>	}
4238	>
4239	>	/**
4240	>	* Returns the result of accumulating the given transformation
4241	>	* of all values using the given reducer to combine values, or
4242	>	* null if none.
4243	>	*
4244	>	* @param transformer a function returning the transformation
4245	>	* for an element, or null if there is no transformation (in
4246	>	* which case it is not combined).
4247	>	* @param reducer a commutative associative combining function
4248	>	* @return the result of accumulating the given transformation
4249	>	* of all values
4250	>	*/
4251	>	public <U> U reduceValuesInParallel
4252	>	(Function<? super V, ? extends U> transformer,
4253	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4254	>	return ForkJoinTasks.reduceValues
4255	>	(this, transformer, reducer).invoke();
4256	>	}
4257	>
4258	>	/**
4259	>	* Returns the result of accumulating the given transformation
4260	>	* of all values using the given reducer to combine values,
4261	>	* and the given basis as an identity value.
4262	>	*
4263	>	* @param transformer a function returning the transformation
4264	>	* for an element
4265	>	* @param basis the identity (initial default value) for the reduction
4266	>	* @param reducer a commutative associative combining function
4267	>	* @return the result of accumulating the given transformation
4268	>	* of all values
4269	>	*/
4270	>	public double reduceValuesToDoubleInParallel
4271	>	(DoubleFunction<? super V> transformer,
4272	>	double basis,
4273	>	DoubleBinaryOperator reducer) {
4274	>	return ForkJoinTasks.reduceValuesToDouble
4275	>	(this, transformer, basis, reducer).invoke();
4276	>	}
4277	>
4278	>	/**
4279	>	* Returns the result of accumulating the given transformation
4280	>	* of all values using the given reducer to combine values,
4281	>	* and the given basis as an identity value.
4282	>	*
4283	>	* @param transformer a function returning the transformation
4284	>	* for an element
4285	>	* @param basis the identity (initial default value) for the reduction
4286	>	* @param reducer a commutative associative combining function
4287	>	* @return the result of accumulating the given transformation
4288	>	* of all values
4289	>	*/
4290	>	public long reduceValuesToLongInParallel
4291	>	(LongFunction<? super V> transformer,
4292	>	long basis,
4293	>	LongBinaryOperator reducer) {
4294	>	return ForkJoinTasks.reduceValuesToLong
4295	>	(this, transformer, basis, reducer).invoke();
4296	>	}
4297	>
4298	>	/**
4299	>	* Returns the result of accumulating the given transformation
4300	>	* of all values using the given reducer to combine values,
4301	>	* and the given basis as an identity value.
4302	>	*
4303	>	* @param transformer a function returning the transformation
4304	>	* for an element
4305	>	* @param basis the identity (initial default value) for the reduction
4306	>	* @param reducer a commutative associative combining function
4307	>	* @return the result of accumulating the given transformation
4308	>	* of all values
4309	>	*/
4310	>	public int reduceValuesToIntInParallel
4311	>	(IntFunction<? super V> transformer,
4312	>	int basis,
4313	>	IntBinaryOperator reducer) {
4314	>	return ForkJoinTasks.reduceValuesToInt
4315	>	(this, transformer, basis, reducer).invoke();
4316	>	}
4317	>
4318	>	/**
4319	>	* Performs the given action for each entry.
4320	>	*
4321	>	* @param action the action
4322	>	*/
4323	>	public void forEachEntryInParallel(Block<? super Map.Entry<K,V>> action) {
4324	>	ForkJoinTasks.forEachEntry
4325	>	(this, action).invoke();
4326	>	}
4327	>
4328	>	/**
4329	>	* Performs the given action for each non-null transformation
4330	>	* of each entry.
4331	>	*
4332	>	* @param transformer a function returning the transformation
4333	>	* for an element, or null if there is no transformation (in
4334	>	* which case the action is not applied).
4335	>	* @param action the action
4336	>	*/
4337	>	public <U> void forEachEntryInParallel
4338	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4339	>	Block<? super U> action) {
4340	>	ForkJoinTasks.forEachEntry
4341	>	(this, transformer, action).invoke();
4342	>	}
4343	>
4344	>	/**
4345	>	* Returns a non-null result from applying the given search
4346	>	* function on each entry, or null if none.  Upon success,
4347	>	* further element processing is suppressed and the results of
4348	>	* any other parallel invocations of the search function are
4349	>	* ignored.
4350	>	*
4351	>	* @param searchFunction a function returning a non-null
4352	>	* result on success, else null
4353	>	* @return a non-null result from applying the given search
4354	>	* function on each entry, or null if none
4355	>	*/
4356	>	public <U> U searchEntriesInParallel
4357	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4358	>	return ForkJoinTasks.searchEntries
4359	>	(this, searchFunction).invoke();
4360	>	}
4361	>
4362	>	/**
4363	>	* Returns the result of accumulating all entries using the
4364	>	* given reducer to combine values, or null if none.
4365	>	*
4366	>	* @param reducer a commutative associative combining function
4367	>	* @return the result of accumulating all entries
4368	>	*/
4369	>	public Map.Entry<K,V> reduceEntriesInParallel
4370	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4371	>	return ForkJoinTasks.reduceEntries
4372	>	(this, reducer).invoke();
4373	>	}
4374	>
4375	>	/**
4376	>	* Returns the result of accumulating the given transformation
4377	>	* of all entries using the given reducer to combine values,
4378	>	* or null if none.
4379	>	*
4380	>	* @param transformer a function returning the transformation
4381	>	* for an element, or null if there is no transformation (in
4382	>	* which case it is not combined).
4383	>	* @param reducer a commutative associative combining function
4384	>	* @return the result of accumulating the given transformation
4385	>	* of all entries
4386	>	*/
4387	>	public <U> U reduceEntriesInParallel
4388	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4389	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4390	>	return ForkJoinTasks.reduceEntries
4391	>	(this, transformer, reducer).invoke();
4392	>	}
4393	>
4394	>	/**
4395	>	* Returns the result of accumulating the given transformation
4396	>	* of all entries using the given reducer to combine values,
4397	>	* and the given basis as an identity value.
4398	>	*
4399	>	* @param transformer a function returning the transformation
4400	>	* for an element
4401	>	* @param basis the identity (initial default value) for the reduction
4402	>	* @param reducer a commutative associative combining function
4403	>	* @return the result of accumulating the given transformation
4404	>	* of all entries
4405	>	*/
4406	>	public double reduceEntriesToDoubleInParallel
4407	>	(DoubleFunction<Map.Entry<K,V>> transformer,
4408	>	double basis,
4409	>	DoubleBinaryOperator reducer) {
4410	>	return ForkJoinTasks.reduceEntriesToDouble
4411	>	(this, transformer, basis, reducer).invoke();
4412	>	}
4413	>
4414	>	/**
4415	>	* Returns the result of accumulating the given transformation
4416	>	* of all entries using the given reducer to combine values,
4417	>	* and the given basis as an identity value.
4418	>	*
4419	>	* @param transformer a function returning the transformation
4420	>	* for an element
4421	>	* @param basis the identity (initial default value) for the reduction
4422	>	* @param reducer a commutative associative combining function
4423	>	* @return the result of accumulating the given transformation
4424	>	* of all entries
4425	>	*/
4426	>	public long reduceEntriesToLongInParallel
4427	>	(LongFunction<Map.Entry<K,V>> transformer,
4428	>	long basis,
4429	>	LongBinaryOperator reducer) {
4430	>	return ForkJoinTasks.reduceEntriesToLong
4431	>	(this, transformer, basis, reducer).invoke();
4432	>	}
4433	>
4434	>	/**
4435	>	* Returns the result of accumulating the given transformation
4436	>	* of all entries using the given reducer to combine values,
4437	>	* and the given basis as an identity value.
4438	>	*
4439	>	* @param transformer a function returning the transformation
4440	>	* for an element
4441	>	* @param basis the identity (initial default value) for the reduction
4442	>	* @param reducer a commutative associative combining function
4443	>	* @return the result of accumulating the given transformation
4444	>	* of all entries
4445	>	*/
4446	>	public int reduceEntriesToIntInParallel
4447	>	(IntFunction<Map.Entry<K,V>> transformer,
4448	>	int basis,
4449	>	IntBinaryOperator reducer) {
4450	>	return ForkJoinTasks.reduceEntriesToInt
4451	>	(this, transformer, basis, reducer).invoke();
4452	>	}
4453	>
4454	>
4455	>	/* ----------------Views -------------- */
4456	>
4457	>	/**
4458	>	* Base class for views.
4459	>	*/
4460	>	abstract static class CHMView<K, V> implements java.io.Serializable {
4461	>	private static final long serialVersionUID = 7249069246763182397L;
4462	>	final ConcurrentHashMap<K, V> map;
4463	>	CHMView(ConcurrentHashMap<K, V> map)  { this.map = map; }
4464	>
4465	>	/**
4466	>	* Returns the map backing this view.
4467	>	*
4468	>	* @return the map backing this view
4469	>	*/
4470	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4471	>
4472	>	public final int size()                 { return map.size(); }
4473	>	public final boolean isEmpty()          { return map.isEmpty(); }
4474	>	public final void clear()               { map.clear(); }
4475	>
4476	>	// implementations below rely on concrete classes supplying these
4477	>	public abstract Iterator<?> iterator();
4478	>	public abstract boolean contains(Object o);
4479	>	public abstract boolean remove(Object o);
4480	>
4481	>	private static final String oomeMsg = "Required array size too large";
4482	>
4483	>	public final Object[] toArray() {
4484	>	long sz = map.mappingCount();
4485	>	if (sz > (long)(MAX_ARRAY_SIZE))
4486	>	throw new OutOfMemoryError(oomeMsg);
4487	>	int n = (int)sz;
4488	>	Object[] r = new Object[n];
4489	>	int i = 0;
4490	>	Iterator<?> it = iterator();
4491	>	while (it.hasNext()) {
4492	>	if (i == n) {
4493	>	if (n >= MAX_ARRAY_SIZE)
4494	>	throw new OutOfMemoryError(oomeMsg);
4495	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4496	>	n = MAX_ARRAY_SIZE;
4497	>	else
4498	>	n += (n >>> 1) + 1;
4499	>	r = Arrays.copyOf(r, n);
4500	>	}
4501	>	r[i++] = it.next();
4502	>	}
4503	>	return (i == n) ? r : Arrays.copyOf(r, i);
4504		}
4505	<	public boolean contains(Object o) {
4506	<	if (!(o instanceof Map.Entry))
4507	<	return false;
4508	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
4509	<	V v = ConcurrentHashMap.this.get(e.getKey());
4510	<	return v != null && v.equals(e.getValue());
4505	>
4506	>	@SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
4507	>	long sz = map.mappingCount();
4508	>	if (sz > (long)(MAX_ARRAY_SIZE))
4509	>	throw new OutOfMemoryError(oomeMsg);
4510	>	int m = (int)sz;
4511	>	T[] r = (a.length >= m) ? a :
4512	>	(T[])java.lang.reflect.Array
4513	>	.newInstance(a.getClass().getComponentType(), m);
4514	>	int n = r.length;
4515	>	int i = 0;
4516	>	Iterator<?> it = iterator();
4517	>	while (it.hasNext()) {
4518	>	if (i == n) {
4519	>	if (n >= MAX_ARRAY_SIZE)
4520	>	throw new OutOfMemoryError(oomeMsg);
4521	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4522	>	n = MAX_ARRAY_SIZE;
4523	>	else
4524	>	n += (n >>> 1) + 1;
4525	>	r = Arrays.copyOf(r, n);
4526	>	}
4527	>	r[i++] = (T)it.next();
4528	>	}
4529	>	if (a == r && i < n) {
4530	>	r[i] = null; // null-terminate
4531	>	return r;
4532	>	}
4533	>	return (i == n) ? r : Arrays.copyOf(r, i);
4534		}
4535	<	public boolean remove(Object o) {
4536	<	if (!(o instanceof Map.Entry))
4537	<	return false;
4538	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
4539	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4535	>
4536	>	public final int hashCode() {
4537	>	int h = 0;
4538	>	for (Iterator<?> it = iterator(); it.hasNext();)
4539	>	h += it.next().hashCode();
4540	>	return h;
4541		}
4542	<	public int size() {
4543	<	return ConcurrentHashMap.this.size();
4542	>
4543	>	public final String toString() {
4544	>	StringBuilder sb = new StringBuilder();
4545	>	sb.append('[');
4546	>	Iterator<?> it = iterator();
4547	>	if (it.hasNext()) {
4548	>	for (;;) {
4549	>	Object e = it.next();
4550	>	sb.append(e == this ? "(this Collection)" : e);
4551	>	if (!it.hasNext())
4552	>	break;
4553	>	sb.append(',').append(' ');
4554	>	}
4555	>	}
4556	>	return sb.append(']').toString();
4557		}
4558	<	public void clear() {
4559	<	ConcurrentHashMap.this.clear();
4558	>
4559	>	public final boolean containsAll(Collection<?> c) {
4560	>	if (c != this) {
4561	>	for (Iterator<?> it = c.iterator(); it.hasNext();) {
4562	>	Object e = it.next();
4563	>	if (e == null || !contains(e))
4564	>	return false;
4565	>	}
4566	>	}
4567	>	return true;
4568		}
1072	–	}
4569
4570	<	/* ---------------- Serialization Support -------------- */
4570	>	public final boolean removeAll(Collection<?> c) {
4571	>	boolean modified = false;
4572	>	for (Iterator<?> it = iterator(); it.hasNext();) {
4573	>	if (c.contains(it.next())) {
4574	>	it.remove();
4575	>	modified = true;
4576	>	}
4577	>	}
4578	>	return modified;
4579	>	}
4580	>
4581	>	public final boolean retainAll(Collection<?> c) {
4582	>	boolean modified = false;
4583	>	for (Iterator<?> it = iterator(); it.hasNext();) {
4584	>	if (!c.contains(it.next())) {
4585	>	it.remove();
4586	>	modified = true;
4587	>	}
4588	>	}
4589	>	return modified;
4590	>	}
4591	>
4592	>	}
4593
4594		/**
4595	<	* Save the state of the <tt>ConcurrentHashMap</tt>
4596	<	* instance to a stream (i.e.,
4597	<	* serialize it).
4598	<	* @param s the stream
4599	<	* @serialData
1082	<	* the key (Object) and value (Object)
1083	<	* for each key-value mapping, followed by a null pair.
1084	<	* The key-value mappings are emitted in no particular order.
4595	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4596	>	* which additions may optionally be enabled by mapping to a
4597	>	* common value.  This class cannot be directly instantiated. See
4598	>	* {@link #keySet}, {@link #keySet(Object)}, {@link #newKeySet()},
4599	>	* {@link #newKeySet(int)}.
4600		*/
4601	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
4602	<	s.defaultWriteObject();
4601	>	public static class KeySetView<K,V> extends CHMView<K,V>
4602	>	implements Set<K>, java.io.Serializable {
4603	>	private static final long serialVersionUID = 7249069246763182397L;
4604	>	private final V value;
4605	>	KeySetView(ConcurrentHashMap<K, V> map, V value) {  // non-public
4606	>	super(map);
4607	>	this.value = value;
4608	>	}
4609
4610	<	for (int k = 0; k < segments.length; ++k) {
4611	<	Segment<K,V> seg = (Segment<K,V>)segments[k];
4612	<	seg.lock();
4613	<	try {
4614	<	HashEntry[] tab = seg.table;
4615	<	for (int i = 0; i < tab.length; ++i) {
4616	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i]; e != null; e = e.next) {
4617	<	s.writeObject(e.key);
4618	<	s.writeObject(e.value);
4610	>	/**
4611	>	* Returns the default mapped value for additions,
4612	>	* or {@code null} if additions are not supported.
4613	>	*
4614	>	* @return the default mapped value for additions, or {@code null}
4615	>	* if not supported.
4616	>	*/
4617	>	public V getMappedValue() { return value; }
4618	>
4619	>	// implement Set API
4620	>
4621	>	public boolean contains(Object o) { return map.containsKey(o); }
4622	>	public boolean remove(Object o)   { return map.remove(o) != null; }
4623	>
4624	>	/**
4625	>	* Returns a "weakly consistent" iterator that will never
4626	>	* throw {@link ConcurrentModificationException}, and
4627	>	* guarantees to traverse elements as they existed upon
4628	>	* construction of the iterator, and may (but is not
4629	>	* guaranteed to) reflect any modifications subsequent to
4630	>	* construction.
4631	>	*
4632	>	* @return an iterator over the keys of this map
4633	>	*/
4634	>	public Iterator<K> iterator()     { return new KeyIterator<K,V>(map); }
4635	>	public boolean add(K e) {
4636	>	V v;
4637	>	if ((v = value) == null)
4638	>	throw new UnsupportedOperationException();
4639	>	if (e == null)
4640	>	throw new NullPointerException();
4641	>	return map.internalPut(e, v, true) == null;
4642	>	}
4643	>	public boolean addAll(Collection<? extends K> c) {
4644	>	boolean added = false;
4645	>	V v;
4646	>	if ((v = value) == null)
4647	>	throw new UnsupportedOperationException();
4648	>	for (K e : c) {
4649	>	if (e == null)
4650	>	throw new NullPointerException();
4651	>	if (map.internalPut(e, v, true) == null)
4652	>	added = true;
4653	>	}
4654	>	return added;
4655	>	}
4656	>	public boolean equals(Object o) {
4657	>	Set<?> c;
4658	>	return ((o instanceof Set) &&
4659	>	((c = (Set<?>)o) == this ||
4660	>	(containsAll(c) && c.containsAll(this))));
4661	>	}
4662	>
4663	>	public Stream<K> stream() {
4664	>	return Streams.stream(() -> new KeyIterator<K,V>(map), 0);
4665	>	}
4666	>	public Stream<K> parallelStream() {
4667	>	return Streams.parallelStream(() -> new KeyIterator<K,V>(map, null),
4668	>	0);
4669	>	}
4670	>	}
4671	>
4672	>	/**
4673	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4674	>	* values, in which additions are disabled. This class cannot be
4675	>	* directly instantiated. See {@link #values},
4676	>	*
4677	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
4678	>	* that will never throw {@link ConcurrentModificationException},
4679	>	* and guarantees to traverse elements as they existed upon
4680	>	* construction of the iterator, and may (but is not guaranteed to)
4681	>	* reflect any modifications subsequent to construction.
4682	>	*/
4683	>	public static final class ValuesView<K,V> extends CHMView<K,V>
4684	>	implements Collection<V> {
4685	>	private static final long serialVersionUID = 2249069246763182397L;
4686	>	ValuesView(ConcurrentHashMap<K, V> map)   { super(map); }
4687	>	public final boolean contains(Object o) { return map.containsValue(o); }
4688	>	public final boolean remove(Object o) {
4689	>	if (o != null) {
4690	>	Iterator<V> it = new ValueIterator<K,V>(map);
4691	>	while (it.hasNext()) {
4692	>	if (o.equals(it.next())) {
4693	>	it.remove();
4694	>	return true;
4695		}
4696		}
1100	–	} finally {
1101	–	seg.unlock();
4697		}
4698	+	return false;
4699		}
4700	<	s.writeObject(null);
4701	<	s.writeObject(null);
4700	>
4701	>	/**
4702	>	* Returns a "weakly consistent" iterator that will never
4703	>	* throw {@link ConcurrentModificationException}, and
4704	>	* guarantees to traverse elements as they existed upon
4705	>	* construction of the iterator, and may (but is not
4706	>	* guaranteed to) reflect any modifications subsequent to
4707	>	* construction.
4708	>	*
4709	>	* @return an iterator over the values of this map
4710	>	*/
4711	>	public final Iterator<V> iterator() {
4712	>	return new ValueIterator<K,V>(map);
4713	>	}
4714	>	public final boolean add(V e) {
4715	>	throw new UnsupportedOperationException();
4716	>	}
4717	>	public final boolean addAll(Collection<? extends V> c) {
4718	>	throw new UnsupportedOperationException();
4719	>	}
4720	>
4721	>	public Stream<V> stream() {
4722	>	return Streams.stream(() -> new ValueIterator<K,V>(map), 0);
4723	>	}
4724	>
4725	>	public Stream<V> parallelStream() {
4726	>	return Streams.parallelStream(() -> new ValueIterator<K,V>(map, null),
4727	>	0);
4728	>	}
4729	>
4730		}
4731
4732		/**
4733	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
4734	<	* instance from a stream (i.e.,
4735	<	* deserialize it).
1112	<	* @param s the stream
4733	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4734	>	* entries.  This class cannot be directly instantiated. See
4735	>	* {@link #entrySet}.
4736		*/
4737	<	private void readObject(java.io.ObjectInputStream s)
4738	<	throws IOException, ClassNotFoundException  {
4739	<	s.defaultReadObject();
4737	>	public static final class EntrySetView<K,V> extends CHMView<K,V>
4738	>	implements Set<Map.Entry<K,V>> {
4739	>	private static final long serialVersionUID = 2249069246763182397L;
4740	>	EntrySetView(ConcurrentHashMap<K, V> map) { super(map); }
4741	>	public final boolean contains(Object o) {
4742	>	Object k, v, r; Map.Entry<?,?> e;
4743	>	return ((o instanceof Map.Entry) &&
4744	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4745	>	(r = map.get(k)) != null &&
4746	>	(v = e.getValue()) != null &&
4747	>	(v == r || v.equals(r)));
4748	>	}
4749	>	public final boolean remove(Object o) {
4750	>	Object k, v; Map.Entry<?,?> e;
4751	>	return ((o instanceof Map.Entry) &&
4752	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4753	>	(v = e.getValue()) != null &&
4754	>	map.remove(k, v));
4755	>	}
4756
4757	<	// Initialize each segment to be minimally sized, and let grow.
4758	<	for (int i = 0; i < segments.length; ++i) {
4759	<	segments[i].setTable(new HashEntry[1]);
4757	>	/**
4758	>	* Returns a "weakly consistent" iterator that will never
4759	>	* throw {@link ConcurrentModificationException}, and
4760	>	* guarantees to traverse elements as they existed upon
4761	>	* construction of the iterator, and may (but is not
4762	>	* guaranteed to) reflect any modifications subsequent to
4763	>	* construction.
4764	>	*
4765	>	* @return an iterator over the entries of this map
4766	>	*/
4767	>	public final Iterator<Map.Entry<K,V>> iterator() {
4768	>	return new EntryIterator<K,V>(map);
4769		}
4770
4771	<	// Read the keys and values, and put the mappings in the table
4772	<	for (;;) {
4773	<	K key = (K) s.readObject();
4774	<	V value = (V) s.readObject();
4775	<	if (key == null)
4776	<	break;
4777	<	put(key, value);
4771	>	public final boolean add(Entry<K,V> e) {
4772	>	K key = e.getKey();
4773	>	V value = e.getValue();
4774	>	if (key == null || value == null)
4775	>	throw new NullPointerException();
4776	>	return map.internalPut(key, value, false) == null;
4777	>	}
4778	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
4779	>	boolean added = false;
4780	>	for (Entry<K,V> e : c) {
4781	>	if (add(e))
4782	>	added = true;
4783	>	}
4784	>	return added;
4785	>	}
4786	>	public boolean equals(Object o) {
4787	>	Set<?> c;
4788	>	return ((o instanceof Set) &&
4789	>	((c = (Set<?>)o) == this ||
4790	>	(containsAll(c) && c.containsAll(this))));
4791	>	}
4792	>
4793	>	public Stream<Map.Entry<K,V>> stream() {
4794	>	return Streams.stream(() -> new EntryIterator<K,V>(map), 0);
4795	>	}
4796	>
4797	>	public Stream<Map.Entry<K,V>> parallelStream() {
4798	>	return Streams.parallelStream(() -> new EntryIterator<K,V>(map, null),
4799	>	0);
4800		}
4801		}
1132	–	}
4802
4803	+	// ---------------------------------------------------------------------
4804	+
4805	+	/**
4806	+	* Predefined tasks for performing bulk parallel operations on
4807	+	* ConcurrentHashMaps. These tasks follow the forms and rules used
4808	+	* for bulk operations. Each method has the same name, but returns
4809	+	* a task rather than invoking it. These methods may be useful in
4810	+	* custom applications such as submitting a task without waiting
4811	+	* for completion, using a custom pool, or combining with other
4812	+	* tasks.
4813	+	*/
4814	+	public static class ForkJoinTasks {
4815	+	private ForkJoinTasks() {}
4816	+
4817	+	/**
4818	+	* Returns a task that when invoked, performs the given
4819	+	* action for each (key, value)
4820	+	*
4821	+	* @param map the map
4822	+	* @param action the action
4823	+	* @return the task
4824	+	*/
4825	+	public static <K,V> ForkJoinTask<Void> forEach
4826	+	(ConcurrentHashMap<K,V> map,
4827	+	BiBlock<? super K, ? super V> action) {
4828	+	if (action == null) throw new NullPointerException();
4829	+	return new ForEachMappingTask<K,V>(map, null, -1, action);
4830	+	}
4831	+
4832	+	/**
4833	+	* Returns a task that when invoked, performs the given
4834	+	* action for each non-null transformation of each (key, value)
4835	+	*
4836	+	* @param map the map
4837	+	* @param transformer a function returning the transformation
4838	+	* for an element, or null if there is no transformation (in
4839	+	* which case the action is not applied)
4840	+	* @param action the action
4841	+	* @return the task
4842	+	*/
4843	+	public static <K,V,U> ForkJoinTask<Void> forEach
4844	+	(ConcurrentHashMap<K,V> map,
4845	+	BiFunction<? super K, ? super V, ? extends U> transformer,
4846	+	Block<? super U> action) {
4847	+	if (transformer == null || action == null)
4848	+	throw new NullPointerException();
4849	+	return new ForEachTransformedMappingTask<K,V,U>
4850	+	(map, null, -1, transformer, action);
4851	+	}
4852	+
4853	+	/**
4854	+	* Returns a task that when invoked, returns a non-null result
4855	+	* from applying the given search function on each (key,
4856	+	* value), or null if none. Upon success, further element
4857	+	* processing is suppressed and the results of any other
4858	+	* parallel invocations of the search function are ignored.
4859	+	*
4860	+	* @param map the map
4861	+	* @param searchFunction a function returning a non-null
4862	+	* result on success, else null
4863	+	* @return the task
4864	+	*/
4865	+	public static <K,V,U> ForkJoinTask<U> search
4866	+	(ConcurrentHashMap<K,V> map,
4867	+	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
4868	+	if (searchFunction == null) throw new NullPointerException();
4869	+	return new SearchMappingsTask<K,V,U>
4870	+	(map, null, -1, searchFunction,
4871	+	new AtomicReference<U>());
4872	+	}
4873	+
4874	+	/**
4875	+	* Returns a task that when invoked, returns the result of
4876	+	* accumulating the given transformation of all (key, value) pairs
4877	+	* using the given reducer to combine values, or null if none.
4878	+	*
4879	+	* @param map the map
4880	+	* @param transformer a function returning the transformation
4881	+	* for an element, or null if there is no transformation (in
4882	+	* which case it is not combined).
4883	+	* @param reducer a commutative associative combining function
4884	+	* @return the task
4885	+	*/
4886	+	public static <K,V,U> ForkJoinTask<U> reduce
4887	+	(ConcurrentHashMap<K,V> map,
4888	+	BiFunction<? super K, ? super V, ? extends U> transformer,
4889	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4890	+	if (transformer == null || reducer == null)
4891	+	throw new NullPointerException();
4892	+	return new MapReduceMappingsTask<K,V,U>
4893	+	(map, null, -1, null, transformer, reducer);
4894	+	}
4895	+
4896	+	/**
4897	+	* Returns a task that when invoked, returns the result of
4898	+	* accumulating the given transformation of all (key, value) pairs
4899	+	* using the given reducer to combine values, and the given
4900	+	* basis as an identity value.
4901	+	*
4902	+	* @param map the map
4903	+	* @param transformer a function returning the transformation
4904	+	* for an element
4905	+	* @param basis the identity (initial default value) for the reduction
4906	+	* @param reducer a commutative associative combining function
4907	+	* @return the task
4908	+	*/
4909	+	public static <K,V> ForkJoinTask<Double> reduceToDouble
4910	+	(ConcurrentHashMap<K,V> map,
4911	+	DoubleBiFunction<? super K, ? super V> transformer,
4912	+	double basis,
4913	+	DoubleBinaryOperator reducer) {
4914	+	if (transformer == null || reducer == null)
4915	+	throw new NullPointerException();
4916	+	return new MapReduceMappingsToDoubleTask<K,V>
4917	+	(map, null, -1, null, transformer, basis, reducer);
4918	+	}
4919	+
4920	+	/**
4921	+	* Returns a task that when invoked, returns the result of
4922	+	* accumulating the given transformation of all (key, value) pairs
4923	+	* using the given reducer to combine values, and the given
4924	+	* basis as an identity value.
4925	+	*
4926	+	* @param map the map
4927	+	* @param transformer a function returning the transformation
4928	+	* for an element
4929	+	* @param basis the identity (initial default value) for the reduction
4930	+	* @param reducer a commutative associative combining function
4931	+	* @return the task
4932	+	*/
4933	+	public static <K,V> ForkJoinTask<Long> reduceToLong
4934	+	(ConcurrentHashMap<K,V> map,
4935	+	LongBiFunction<? super K, ? super V> transformer,
4936	+	long basis,
4937	+	LongBinaryOperator reducer) {
4938	+	if (transformer == null || reducer == null)
4939	+	throw new NullPointerException();
4940	+	return new MapReduceMappingsToLongTask<K,V>
4941	+	(map, null, -1, null, transformer, basis, reducer);
4942	+	}
4943	+
4944	+	/**
4945	+	* Returns a task that when invoked, returns the result of
4946	+	* accumulating the given transformation of all (key, value) pairs
4947	+	* using the given reducer to combine values, and the given
4948	+	* basis as an identity value.
4949	+	*
4950	+	* @param transformer a function returning the transformation
4951	+	* for an element
4952	+	* @param basis the identity (initial default value) for the reduction
4953	+	* @param reducer a commutative associative combining function
4954	+	* @return the task
4955	+	*/
4956	+	public static <K,V> ForkJoinTask<Integer> reduceToInt
4957	+	(ConcurrentHashMap<K,V> map,
4958	+	IntBiFunction<? super K, ? super V> transformer,
4959	+	int basis,
4960	+	IntBinaryOperator reducer) {
4961	+	if (transformer == null || reducer == null)
4962	+	throw new NullPointerException();
4963	+	return new MapReduceMappingsToIntTask<K,V>
4964	+	(map, null, -1, null, transformer, basis, reducer);
4965	+	}
4966	+
4967	+	/**
4968	+	* Returns a task that when invoked, performs the given action
4969	+	* for each key.
4970	+	*
4971	+	* @param map the map
4972	+	* @param action the action
4973	+	* @return the task
4974	+	*/
4975	+	public static <K,V> ForkJoinTask<Void> forEachKey
4976	+	(ConcurrentHashMap<K,V> map,
4977	+	Block<? super K> action) {
4978	+	if (action == null) throw new NullPointerException();
4979	+	return new ForEachKeyTask<K,V>(map, null, -1, action);
4980	+	}
4981	+
4982	+	/**
4983	+	* Returns a task that when invoked, performs the given action
4984	+	* for each non-null transformation of each key.
4985	+	*
4986	+	* @param map the map
4987	+	* @param transformer a function returning the transformation
4988	+	* for an element, or null if there is no transformation (in
4989	+	* which case the action is not applied)
4990	+	* @param action the action
4991	+	* @return the task
4992	+	*/
4993	+	public static <K,V,U> ForkJoinTask<Void> forEachKey
4994	+	(ConcurrentHashMap<K,V> map,
4995	+	Function<? super K, ? extends U> transformer,
4996	+	Block<? super U> action) {
4997	+	if (transformer == null || action == null)
4998	+	throw new NullPointerException();
4999	+	return new ForEachTransformedKeyTask<K,V,U>
5000	+	(map, null, -1, transformer, action);
5001	+	}
5002	+
5003	+	/**
5004	+	* Returns a task that when invoked, returns a non-null result
5005	+	* from applying the given search function on each key, or
5006	+	* null if none.  Upon success, further element processing is
5007	+	* suppressed and the results of any other parallel
5008	+	* invocations of the search function are ignored.
5009	+	*
5010	+	* @param map the map
5011	+	* @param searchFunction a function returning a non-null
5012	+	* result on success, else null
5013	+	* @return the task
5014	+	*/
5015	+	public static <K,V,U> ForkJoinTask<U> searchKeys
5016	+	(ConcurrentHashMap<K,V> map,
5017	+	Function<? super K, ? extends U> searchFunction) {
5018	+	if (searchFunction == null) throw new NullPointerException();
5019	+	return new SearchKeysTask<K,V,U>
5020	+	(map, null, -1, searchFunction,
5021	+	new AtomicReference<U>());
5022	+	}
5023	+
5024	+	/**
5025	+	* Returns a task that when invoked, returns the result of
5026	+	* accumulating all keys using the given reducer to combine
5027	+	* values, or null if none.
5028	+	*
5029	+	* @param map the map
5030	+	* @param reducer a commutative associative combining function
5031	+	* @return the task
5032	+	*/
5033	+	public static <K,V> ForkJoinTask<K> reduceKeys
5034	+	(ConcurrentHashMap<K,V> map,
5035	+	BiFunction<? super K, ? super K, ? extends K> reducer) {
5036	+	if (reducer == null) throw new NullPointerException();
5037	+	return new ReduceKeysTask<K,V>
5038	+	(map, null, -1, null, reducer);
5039	+	}
5040	+
5041	+	/**
5042	+	* Returns a task that when invoked, returns the result of
5043	+	* accumulating the given transformation of all keys using the given
5044	+	* reducer to combine values, or null if none.
5045	+	*
5046	+	* @param map the map
5047	+	* @param transformer a function returning the transformation
5048	+	* for an element, or null if there is no transformation (in
5049	+	* which case it is not combined).
5050	+	* @param reducer a commutative associative combining function
5051	+	* @return the task
5052	+	*/
5053	+	public static <K,V,U> ForkJoinTask<U> reduceKeys
5054	+	(ConcurrentHashMap<K,V> map,
5055	+	Function<? super K, ? extends U> transformer,
5056	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
5057	+	if (transformer == null || reducer == null)
5058	+	throw new NullPointerException();
5059	+	return new MapReduceKeysTask<K,V,U>
5060	+	(map, null, -1, null, transformer, reducer);
5061	+	}
5062	+
5063	+	/**
5064	+	* Returns a task that when invoked, returns the result of
5065	+	* accumulating the given transformation of all keys using the given
5066	+	* reducer to combine values, and the given basis as an
5067	+	* identity value.
5068	+	*
5069	+	* @param map the map
5070	+	* @param transformer a function returning the transformation
5071	+	* for an element
5072	+	* @param basis the identity (initial default value) for the reduction
5073	+	* @param reducer a commutative associative combining function
5074	+	* @return the task
5075	+	*/
5076	+	public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
5077	+	(ConcurrentHashMap<K,V> map,
5078	+	DoubleFunction<? super K> transformer,
5079	+	double basis,
5080	+	DoubleBinaryOperator reducer) {
5081	+	if (transformer == null || reducer == null)
5082	+	throw new NullPointerException();
5083	+	return new MapReduceKeysToDoubleTask<K,V>
5084	+	(map, null, -1, null, transformer, basis, reducer);
5085	+	}
5086	+
5087	+	/**
5088	+	* Returns a task that when invoked, returns the result of
5089	+	* accumulating the given transformation of all keys using the given
5090	+	* reducer to combine values, and the given basis as an
5091	+	* identity value.
5092	+	*
5093	+	* @param map the map
5094	+	* @param transformer a function returning the transformation
5095	+	* for an element
5096	+	* @param basis the identity (initial default value) for the reduction
5097	+	* @param reducer a commutative associative combining function
5098	+	* @return the task
5099	+	*/
5100	+	public static <K,V> ForkJoinTask<Long> reduceKeysToLong
5101	+	(ConcurrentHashMap<K,V> map,
5102	+	LongFunction<? super K> transformer,
5103	+	long basis,
5104	+	LongBinaryOperator reducer) {
5105	+	if (transformer == null || reducer == null)
5106	+	throw new NullPointerException();
5107	+	return new MapReduceKeysToLongTask<K,V>
5108	+	(map, null, -1, null, transformer, basis, reducer);
5109	+	}
5110	+
5111	+	/**
5112	+	* Returns a task that when invoked, returns the result of
5113	+	* accumulating the given transformation of all keys using the given
5114	+	* reducer to combine values, and the given basis as an
5115	+	* identity value.
5116	+	*
5117	+	* @param map the map
5118	+	* @param transformer a function returning the transformation
5119	+	* for an element
5120	+	* @param basis the identity (initial default value) for the reduction
5121	+	* @param reducer a commutative associative combining function
5122	+	* @return the task
5123	+	*/
5124	+	public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
5125	+	(ConcurrentHashMap<K,V> map,
5126	+	IntFunction<? super K> transformer,
5127	+	int basis,
5128	+	IntBinaryOperator reducer) {
5129	+	if (transformer == null || reducer == null)
5130	+	throw new NullPointerException();
5131	+	return new MapReduceKeysToIntTask<K,V>
5132	+	(map, null, -1, null, transformer, basis, reducer);
5133	+	}
5134	+
5135	+	/**
5136	+	* Returns a task that when invoked, performs the given action
5137	+	* for each value.
5138	+	*
5139	+	* @param map the map
5140	+	* @param action the action
5141	+	*/
5142	+	public static <K,V> ForkJoinTask<Void> forEachValue
5143	+	(ConcurrentHashMap<K,V> map,
5144	+	Block<? super V> action) {
5145	+	if (action == null) throw new NullPointerException();
5146	+	return new ForEachValueTask<K,V>(map, null, -1, action);
5147	+	}
5148	+
5149	+	/**
5150	+	* Returns a task that when invoked, performs the given action
5151	+	* for each non-null transformation of each value.
5152	+	*
5153	+	* @param map the map
5154	+	* @param transformer a function returning the transformation
5155	+	* for an element, or null if there is no transformation (in
5156	+	* which case the action is not applied)
5157	+	* @param action the action
5158	+	*/
5159	+	public static <K,V,U> ForkJoinTask<Void> forEachValue
5160	+	(ConcurrentHashMap<K,V> map,
5161	+	Function<? super V, ? extends U> transformer,
5162	+	Block<? super U> action) {
5163	+	if (transformer == null || action == null)
5164	+	throw new NullPointerException();
5165	+	return new ForEachTransformedValueTask<K,V,U>
5166	+	(map, null, -1, transformer, action);
5167	+	}
5168	+
5169	+	/**
5170	+	* Returns a task that when invoked, returns a non-null result
5171	+	* from applying the given search function on each value, or
5172	+	* null if none.  Upon success, further element processing is
5173	+	* suppressed and the results of any other parallel
5174	+	* invocations of the search function are ignored.
5175	+	*
5176	+	* @param map the map
5177	+	* @param searchFunction a function returning a non-null
5178	+	* result on success, else null
5179	+	* @return the task
5180	+	*/
5181	+	public static <K,V,U> ForkJoinTask<U> searchValues
5182	+	(ConcurrentHashMap<K,V> map,
5183	+	Function<? super V, ? extends U> searchFunction) {
5184	+	if (searchFunction == null) throw new NullPointerException();
5185	+	return new SearchValuesTask<K,V,U>
5186	+	(map, null, -1, searchFunction,
5187	+	new AtomicReference<U>());
5188	+	}
5189	+
5190	+	/**
5191	+	* Returns a task that when invoked, returns the result of
5192	+	* accumulating all values using the given reducer to combine
5193	+	* values, or null if none.
5194	+	*
5195	+	* @param map the map
5196	+	* @param reducer a commutative associative combining function
5197	+	* @return the task
5198	+	*/
5199	+	public static <K,V> ForkJoinTask<V> reduceValues
5200	+	(ConcurrentHashMap<K,V> map,
5201	+	BiFunction<? super V, ? super V, ? extends V> reducer) {
5202	+	if (reducer == null) throw new NullPointerException();
5203	+	return new ReduceValuesTask<K,V>
5204	+	(map, null, -1, null, reducer);
5205	+	}
5206	+
5207	+	/**
5208	+	* Returns a task that when invoked, returns the result of
5209	+	* accumulating the given transformation of all values using the
5210	+	* given reducer to combine values, or null if none.
5211	+	*
5212	+	* @param map the map
5213	+	* @param transformer a function returning the transformation
5214	+	* for an element, or null if there is no transformation (in
5215	+	* which case it is not combined).
5216	+	* @param reducer a commutative associative combining function
5217	+	* @return the task
5218	+	*/
5219	+	public static <K,V,U> ForkJoinTask<U> reduceValues
5220	+	(ConcurrentHashMap<K,V> map,
5221	+	Function<? super V, ? extends U> transformer,
5222	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
5223	+	if (transformer == null || reducer == null)
5224	+	throw new NullPointerException();
5225	+	return new MapReduceValuesTask<K,V,U>
5226	+	(map, null, -1, null, transformer, reducer);
5227	+	}
5228	+
5229	+	/**
5230	+	* Returns a task that when invoked, returns the result of
5231	+	* accumulating the given transformation of all values using the
5232	+	* given reducer to combine values, and the given basis as an
5233	+	* identity value.
5234	+	*
5235	+	* @param map the map
5236	+	* @param transformer a function returning the transformation
5237	+	* for an element
5238	+	* @param basis the identity (initial default value) for the reduction
5239	+	* @param reducer a commutative associative combining function
5240	+	* @return the task
5241	+	*/
5242	+	public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
5243	+	(ConcurrentHashMap<K,V> map,
5244	+	DoubleFunction<? super V> transformer,
5245	+	double basis,
5246	+	DoubleBinaryOperator reducer) {
5247	+	if (transformer == null || reducer == null)
5248	+	throw new NullPointerException();
5249	+	return new MapReduceValuesToDoubleTask<K,V>
5250	+	(map, null, -1, null, transformer, basis, reducer);
5251	+	}
5252	+
5253	+	/**
5254	+	* Returns a task that when invoked, returns the result of
5255	+	* accumulating the given transformation of all values using the
5256	+	* given reducer to combine values, and the given basis as an
5257	+	* identity value.
5258	+	*
5259	+	* @param map the map
5260	+	* @param transformer a function returning the transformation
5261	+	* for an element
5262	+	* @param basis the identity (initial default value) for the reduction
5263	+	* @param reducer a commutative associative combining function
5264	+	* @return the task
5265	+	*/
5266	+	public static <K,V> ForkJoinTask<Long> reduceValuesToLong
5267	+	(ConcurrentHashMap<K,V> map,
5268	+	LongFunction<? super V> transformer,
5269	+	long basis,
5270	+	LongBinaryOperator reducer) {
5271	+	if (transformer == null || reducer == null)
5272	+	throw new NullPointerException();
5273	+	return new MapReduceValuesToLongTask<K,V>
5274	+	(map, null, -1, null, transformer, basis, reducer);
5275	+	}
5276	+
5277	+	/**
5278	+	* Returns a task that when invoked, returns the result of
5279	+	* accumulating the given transformation of all values using the
5280	+	* given reducer to combine values, and the given basis as an
5281	+	* identity value.
5282	+	*
5283	+	* @param map the map
5284	+	* @param transformer a function returning the transformation
5285	+	* for an element
5286	+	* @param basis the identity (initial default value) for the reduction
5287	+	* @param reducer a commutative associative combining function
5288	+	* @return the task
5289	+	*/
5290	+	public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
5291	+	(ConcurrentHashMap<K,V> map,
5292	+	IntFunction<? super V> transformer,
5293	+	int basis,
5294	+	IntBinaryOperator reducer) {
5295	+	if (transformer == null || reducer == null)
5296	+	throw new NullPointerException();
5297	+	return new MapReduceValuesToIntTask<K,V>
5298	+	(map, null, -1, null, transformer, basis, reducer);
5299	+	}
5300	+
5301	+	/**
5302	+	* Returns a task that when invoked, perform the given action
5303	+	* for each entry.
5304	+	*
5305	+	* @param map the map
5306	+	* @param action the action
5307	+	*/
5308	+	public static <K,V> ForkJoinTask<Void> forEachEntry
5309	+	(ConcurrentHashMap<K,V> map,
5310	+	Block<? super Map.Entry<K,V>> action) {
5311	+	if (action == null) throw new NullPointerException();
5312	+	return new ForEachEntryTask<K,V>(map, null, -1, action);
5313	+	}
5314	+
5315	+	/**
5316	+	* Returns a task that when invoked, perform the given action
5317	+	* for each non-null transformation of each entry.
5318	+	*
5319	+	* @param map the map
5320	+	* @param transformer a function returning the transformation
5321	+	* for an element, or null if there is no transformation (in
5322	+	* which case the action is not applied)
5323	+	* @param action the action
5324	+	*/
5325	+	public static <K,V,U> ForkJoinTask<Void> forEachEntry
5326	+	(ConcurrentHashMap<K,V> map,
5327	+	Function<Map.Entry<K,V>, ? extends U> transformer,
5328	+	Block<? super U> action) {
5329	+	if (transformer == null || action == null)
5330	+	throw new NullPointerException();
5331	+	return new ForEachTransformedEntryTask<K,V,U>
5332	+	(map, null, -1, transformer, action);
5333	+	}
5334	+
5335	+	/**
5336	+	* Returns a task that when invoked, returns a non-null result
5337	+	* from applying the given search function on each entry, or
5338	+	* null if none.  Upon success, further element processing is
5339	+	* suppressed and the results of any other parallel
5340	+	* invocations of the search function are ignored.
5341	+	*
5342	+	* @param map the map
5343	+	* @param searchFunction a function returning a non-null
5344	+	* result on success, else null
5345	+	* @return the task
5346	+	*/
5347	+	public static <K,V,U> ForkJoinTask<U> searchEntries
5348	+	(ConcurrentHashMap<K,V> map,
5349	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
5350	+	if (searchFunction == null) throw new NullPointerException();
5351	+	return new SearchEntriesTask<K,V,U>
5352	+	(map, null, -1, searchFunction,
5353	+	new AtomicReference<U>());
5354	+	}
5355	+
5356	+	/**
5357	+	* Returns a task that when invoked, returns the result of
5358	+	* accumulating all entries using the given reducer to combine
5359	+	* values, or null if none.
5360	+	*
5361	+	* @param map the map
5362	+	* @param reducer a commutative associative combining function
5363	+	* @return the task
5364	+	*/
5365	+	public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
5366	+	(ConcurrentHashMap<K,V> map,
5367	+	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5368	+	if (reducer == null) throw new NullPointerException();
5369	+	return new ReduceEntriesTask<K,V>
5370	+	(map, null, -1, null, reducer);
5371	+	}
5372	+
5373	+	/**
5374	+	* Returns a task that when invoked, returns the result of
5375	+	* accumulating the given transformation of all entries using the
5376	+	* given reducer to combine values, or null if none.
5377	+	*
5378	+	* @param map the map
5379	+	* @param transformer a function returning the transformation
5380	+	* for an element, or null if there is no transformation (in
5381	+	* which case it is not combined).
5382	+	* @param reducer a commutative associative combining function
5383	+	* @return the task
5384	+	*/
5385	+	public static <K,V,U> ForkJoinTask<U> reduceEntries
5386	+	(ConcurrentHashMap<K,V> map,
5387	+	Function<Map.Entry<K,V>, ? extends U> transformer,
5388	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
5389	+	if (transformer == null || reducer == null)
5390	+	throw new NullPointerException();
5391	+	return new MapReduceEntriesTask<K,V,U>
5392	+	(map, null, -1, null, transformer, reducer);
5393	+	}
5394	+
5395	+	/**
5396	+	* Returns a task that when invoked, returns the result of
5397	+	* accumulating the given transformation of all entries using the
5398	+	* given reducer to combine values, and the given basis as an
5399	+	* identity value.
5400	+	*
5401	+	* @param map the map
5402	+	* @param transformer a function returning the transformation
5403	+	* for an element
5404	+	* @param basis the identity (initial default value) for the reduction
5405	+	* @param reducer a commutative associative combining function
5406	+	* @return the task
5407	+	*/
5408	+	public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
5409	+	(ConcurrentHashMap<K,V> map,
5410	+	DoubleFunction<Map.Entry<K,V>> transformer,
5411	+	double basis,
5412	+	DoubleBinaryOperator reducer) {
5413	+	if (transformer == null || reducer == null)
5414	+	throw new NullPointerException();
5415	+	return new MapReduceEntriesToDoubleTask<K,V>
5416	+	(map, null, -1, null, transformer, basis, reducer);
5417	+	}
5418	+
5419	+	/**
5420	+	* Returns a task that when invoked, returns the result of
5421	+	* accumulating the given transformation of all entries using the
5422	+	* given reducer to combine values, and the given basis as an
5423	+	* identity value.
5424	+	*
5425	+	* @param map the map
5426	+	* @param transformer a function returning the transformation
5427	+	* for an element
5428	+	* @param basis the identity (initial default value) for the reduction
5429	+	* @param reducer a commutative associative combining function
5430	+	* @return the task
5431	+	*/
5432	+	public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
5433	+	(ConcurrentHashMap<K,V> map,
5434	+	LongFunction<Map.Entry<K,V>> transformer,
5435	+	long basis,
5436	+	LongBinaryOperator reducer) {
5437	+	if (transformer == null || reducer == null)
5438	+	throw new NullPointerException();
5439	+	return new MapReduceEntriesToLongTask<K,V>
5440	+	(map, null, -1, null, transformer, basis, reducer);
5441	+	}
5442	+
5443	+	/**
5444	+	* Returns a task that when invoked, returns the result of
5445	+	* accumulating the given transformation of all entries using the
5446	+	* given reducer to combine values, and the given basis as an
5447	+	* identity value.
5448	+	*
5449	+	* @param map the map
5450	+	* @param transformer a function returning the transformation
5451	+	* for an element
5452	+	* @param basis the identity (initial default value) for the reduction
5453	+	* @param reducer a commutative associative combining function
5454	+	* @return the task
5455	+	*/
5456	+	public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
5457	+	(ConcurrentHashMap<K,V> map,
5458	+	IntFunction<Map.Entry<K,V>> transformer,
5459	+	int basis,
5460	+	IntBinaryOperator reducer) {
5461	+	if (transformer == null || reducer == null)
5462	+	throw new NullPointerException();
5463	+	return new MapReduceEntriesToIntTask<K,V>
5464	+	(map, null, -1, null, transformer, basis, reducer);
5465	+	}
5466	+	}
5467	+
5468	+	// -------------------------------------------------------
5469	+
5470	+	/*
5471	+	* Task classes. Coded in a regular but ugly format/style to
5472	+	* simplify checks that each variant differs in the right way from
5473	+	* others. The null screenings exist because compilers cannot tell
5474	+	* that we've already null-checked task arguments, so we force
5475	+	* simplest hoisted bypass to help avoid convoluted traps.
5476	+	*/
5477	+
5478	+	@SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
5479	+	extends Traverser<K,V,Void> {
5480	+	final Block<? super K> action;
5481	+	ForEachKeyTask
5482	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5483	+	Block<? super K> action) {
5484	+	super(m, p, b);
5485	+	this.action = action;
5486	+	}
5487	+	public final void compute() {
5488	+	final Block<? super K> action;
5489	+	if ((action = this.action) != null) {
5490	+	for (int b; (b = preSplit()) > 0;)
5491	+	new ForEachKeyTask<K,V>(map, this, b, action).fork();
5492	+	while (advance() != null)
5493	+	action.accept(nextKey);
5494	+	propagateCompletion();
5495	+	}
5496	+	}
5497	+	}
5498	+
5499	+	@SuppressWarnings("serial") static final class ForEachValueTask<K,V>
5500	+	extends Traverser<K,V,Void> {
5501	+	final Block<? super V> action;
5502	+	ForEachValueTask
5503	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5504	+	Block<? super V> action) {
5505	+	super(m, p, b);
5506	+	this.action = action;
5507	+	}
5508	+	public final void compute() {
5509	+	final Block<? super V> action;
5510	+	if ((action = this.action) != null) {
5511	+	for (int b; (b = preSplit()) > 0;)
5512	+	new ForEachValueTask<K,V>(map, this, b, action).fork();
5513	+	V v;
5514	+	while ((v = advance()) != null)
5515	+	action.accept(v);
5516	+	propagateCompletion();
5517	+	}
5518	+	}
5519	+	}
5520	+
5521	+	@SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5522	+	extends Traverser<K,V,Void> {
5523	+	final Block<? super Entry<K,V>> action;
5524	+	ForEachEntryTask
5525	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5526	+	Block<? super Entry<K,V>> action) {
5527	+	super(m, p, b);
5528	+	this.action = action;
5529	+	}
5530	+	public final void compute() {
5531	+	final Block<? super Entry<K,V>> action;
5532	+	if ((action = this.action) != null) {
5533	+	for (int b; (b = preSplit()) > 0;)
5534	+	new ForEachEntryTask<K,V>(map, this, b, action).fork();
5535	+	V v;
5536	+	while ((v = advance()) != null)
5537	+	action.accept(entryFor(nextKey, v));
5538	+	propagateCompletion();
5539	+	}
5540	+	}
5541	+	}
5542	+
5543	+	@SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5544	+	extends Traverser<K,V,Void> {
5545	+	final BiBlock<? super K, ? super V> action;
5546	+	ForEachMappingTask
5547	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5548	+	BiBlock<? super K,? super V> action) {
5549	+	super(m, p, b);
5550	+	this.action = action;
5551	+	}
5552	+	public final void compute() {
5553	+	final BiBlock<? super K, ? super V> action;
5554	+	if ((action = this.action) != null) {
5555	+	for (int b; (b = preSplit()) > 0;)
5556	+	new ForEachMappingTask<K,V>(map, this, b, action).fork();
5557	+	V v;
5558	+	while ((v = advance()) != null)
5559	+	action.accept(nextKey, v);
5560	+	propagateCompletion();
5561	+	}
5562	+	}
5563	+	}
5564	+
5565	+	@SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5566	+	extends Traverser<K,V,Void> {
5567	+	final Function<? super K, ? extends U> transformer;
5568	+	final Block<? super U> action;
5569	+	ForEachTransformedKeyTask
5570	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5571	+	Function<? super K, ? extends U> transformer, Block<? super U> action) {
5572	+	super(m, p, b);
5573	+	this.transformer = transformer; this.action = action;
5574	+	}
5575	+	public final void compute() {
5576	+	final Function<? super K, ? extends U> transformer;
5577	+	final Block<? super U> action;
5578	+	if ((transformer = this.transformer) != null &&
5579	+	(action = this.action) != null) {
5580	+	for (int b; (b = preSplit()) > 0;)
5581	+	new ForEachTransformedKeyTask<K,V,U>
5582	+	(map, this, b, transformer, action).fork();
5583	+	U u;
5584	+	while (advance() != null) {
5585	+	if ((u = transformer.apply(nextKey)) != null)
5586	+	action.accept(u);
5587	+	}
5588	+	propagateCompletion();
5589	+	}
5590	+	}
5591	+	}
5592	+
5593	+	@SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5594	+	extends Traverser<K,V,Void> {
5595	+	final Function<? super V, ? extends U> transformer;
5596	+	final Block<? super U> action;
5597	+	ForEachTransformedValueTask
5598	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5599	+	Function<? super V, ? extends U> transformer, Block<? super U> action) {
5600	+	super(m, p, b);
5601	+	this.transformer = transformer; this.action = action;
5602	+	}
5603	+	public final void compute() {
5604	+	final Function<? super V, ? extends U> transformer;
5605	+	final Block<? super U> action;
5606	+	if ((transformer = this.transformer) != null &&
5607	+	(action = this.action) != null) {
5608	+	for (int b; (b = preSplit()) > 0;)
5609	+	new ForEachTransformedValueTask<K,V,U>
5610	+	(map, this, b, transformer, action).fork();
5611	+	V v; U u;
5612	+	while ((v = advance()) != null) {
5613	+	if ((u = transformer.apply(v)) != null)
5614	+	action.accept(u);
5615	+	}
5616	+	propagateCompletion();
5617	+	}
5618	+	}
5619	+	}
5620	+
5621	+	@SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5622	+	extends Traverser<K,V,Void> {
5623	+	final Function<Map.Entry<K,V>, ? extends U> transformer;
5624	+	final Block<? super U> action;
5625	+	ForEachTransformedEntryTask
5626	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5627	+	Function<Map.Entry<K,V>, ? extends U> transformer, Block<? super U> action) {
5628	+	super(m, p, b);
5629	+	this.transformer = transformer; this.action = action;
5630	+	}
5631	+	public final void compute() {
5632	+	final Function<Map.Entry<K,V>, ? extends U> transformer;
5633	+	final Block<? super U> action;
5634	+	if ((transformer = this.transformer) != null &&
5635	+	(action = this.action) != null) {
5636	+	for (int b; (b = preSplit()) > 0;)
5637	+	new ForEachTransformedEntryTask<K,V,U>
5638	+	(map, this, b, transformer, action).fork();
5639	+	V v; U u;
5640	+	while ((v = advance()) != null) {
5641	+	if ((u = transformer.apply(entryFor(nextKey,
5642	+	v))) != null)
5643	+	action.accept(u);
5644	+	}
5645	+	propagateCompletion();
5646	+	}
5647	+	}
5648	+	}
5649	+
5650	+	@SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5651	+	extends Traverser<K,V,Void> {
5652	+	final BiFunction<? super K, ? super V, ? extends U> transformer;
5653	+	final Block<? super U> action;
5654	+	ForEachTransformedMappingTask
5655	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5656	+	BiFunction<? super K, ? super V, ? extends U> transformer,
5657	+	Block<? super U> action) {
5658	+	super(m, p, b);
5659	+	this.transformer = transformer; this.action = action;
5660	+	}
5661	+	public final void compute() {
5662	+	final BiFunction<? super K, ? super V, ? extends U> transformer;
5663	+	final Block<? super U> action;
5664	+	if ((transformer = this.transformer) != null &&
5665	+	(action = this.action) != null) {
5666	+	for (int b; (b = preSplit()) > 0;)
5667	+	new ForEachTransformedMappingTask<K,V,U>
5668	+	(map, this, b, transformer, action).fork();
5669	+	V v; U u;
5670	+	while ((v = advance()) != null) {
5671	+	if ((u = transformer.apply(nextKey, v)) != null)
5672	+	action.accept(u);
5673	+	}
5674	+	propagateCompletion();
5675	+	}
5676	+	}
5677	+	}
5678	+
5679	+	@SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5680	+	extends Traverser<K,V,U> {
5681	+	final Function<? super K, ? extends U> searchFunction;
5682	+	final AtomicReference<U> result;
5683	+	SearchKeysTask
5684	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5685	+	Function<? super K, ? extends U> searchFunction,
5686	+	AtomicReference<U> result) {
5687	+	super(m, p, b);
5688	+	this.searchFunction = searchFunction; this.result = result;
5689	+	}
5690	+	public final U getRawResult() { return result.get(); }
5691	+	public final void compute() {
5692	+	final Function<? super K, ? extends U> searchFunction;
5693	+	final AtomicReference<U> result;
5694	+	if ((searchFunction = this.searchFunction) != null &&
5695	+	(result = this.result) != null) {
5696	+	for (int b;;) {
5697	+	if (result.get() != null)
5698	+	return;
5699	+	if ((b = preSplit()) <= 0)
5700	+	break;
5701	+	new SearchKeysTask<K,V,U>
5702	+	(map, this, b, searchFunction, result).fork();
5703	+	}
5704	+	while (result.get() == null) {
5705	+	U u;
5706	+	if (advance() == null) {
5707	+	propagateCompletion();
5708	+	break;
5709	+	}
5710	+	if ((u = searchFunction.apply(nextKey)) != null) {
5711	+	if (result.compareAndSet(null, u))
5712	+	quietlyCompleteRoot();
5713	+	break;
5714	+	}
5715	+	}
5716	+	}
5717	+	}
5718	+	}
5719	+
5720	+	@SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5721	+	extends Traverser<K,V,U> {
5722	+	final Function<? super V, ? extends U> searchFunction;
5723	+	final AtomicReference<U> result;
5724	+	SearchValuesTask
5725	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5726	+	Function<? super V, ? extends U> searchFunction,
5727	+	AtomicReference<U> result) {
5728	+	super(m, p, b);
5729	+	this.searchFunction = searchFunction; this.result = result;
5730	+	}
5731	+	public final U getRawResult() { return result.get(); }
5732	+	public final void compute() {
5733	+	final Function<? super V, ? extends U> searchFunction;
5734	+	final AtomicReference<U> result;
5735	+	if ((searchFunction = this.searchFunction) != null &&
5736	+	(result = this.result) != null) {
5737	+	for (int b;;) {
5738	+	if (result.get() != null)
5739	+	return;
5740	+	if ((b = preSplit()) <= 0)
5741	+	break;
5742	+	new SearchValuesTask<K,V,U>
5743	+	(map, this, b, searchFunction, result).fork();
5744	+	}
5745	+	while (result.get() == null) {
5746	+	V v; U u;
5747	+	if ((v = advance()) == null) {
5748	+	propagateCompletion();
5749	+	break;
5750	+	}
5751	+	if ((u = searchFunction.apply(v)) != null) {
5752	+	if (result.compareAndSet(null, u))
5753	+	quietlyCompleteRoot();
5754	+	break;
5755	+	}
5756	+	}
5757	+	}
5758	+	}
5759	+	}
5760	+
5761	+	@SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5762	+	extends Traverser<K,V,U> {
5763	+	final Function<Entry<K,V>, ? extends U> searchFunction;
5764	+	final AtomicReference<U> result;
5765	+	SearchEntriesTask
5766	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5767	+	Function<Entry<K,V>, ? extends U> searchFunction,
5768	+	AtomicReference<U> result) {
5769	+	super(m, p, b);
5770	+	this.searchFunction = searchFunction; this.result = result;
5771	+	}
5772	+	public final U getRawResult() { return result.get(); }
5773	+	public final void compute() {
5774	+	final Function<Entry<K,V>, ? extends U> searchFunction;
5775	+	final AtomicReference<U> result;
5776	+	if ((searchFunction = this.searchFunction) != null &&
5777	+	(result = this.result) != null) {
5778	+	for (int b;;) {
5779	+	if (result.get() != null)
5780	+	return;
5781	+	if ((b = preSplit()) <= 0)
5782	+	break;
5783	+	new SearchEntriesTask<K,V,U>
5784	+	(map, this, b, searchFunction, result).fork();
5785	+	}
5786	+	while (result.get() == null) {
5787	+	V v; U u;
5788	+	if ((v = advance()) == null) {
5789	+	propagateCompletion();
5790	+	break;
5791	+	}
5792	+	if ((u = searchFunction.apply(entryFor(nextKey,
5793	+	v))) != null) {
5794	+	if (result.compareAndSet(null, u))
5795	+	quietlyCompleteRoot();
5796	+	return;
5797	+	}
5798	+	}
5799	+	}
5800	+	}
5801	+	}
5802	+
5803	+	@SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5804	+	extends Traverser<K,V,U> {
5805	+	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5806	+	final AtomicReference<U> result;
5807	+	SearchMappingsTask
5808	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5809	+	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5810	+	AtomicReference<U> result) {
5811	+	super(m, p, b);
5812	+	this.searchFunction = searchFunction; this.result = result;
5813	+	}
5814	+	public final U getRawResult() { return result.get(); }
5815	+	public final void compute() {
5816	+	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5817	+	final AtomicReference<U> result;
5818	+	if ((searchFunction = this.searchFunction) != null &&
5819	+	(result = this.result) != null) {
5820	+	for (int b;;) {
5821	+	if (result.get() != null)
5822	+	return;
5823	+	if ((b = preSplit()) <= 0)
5824	+	break;
5825	+	new SearchMappingsTask<K,V,U>
5826	+	(map, this, b, searchFunction, result).fork();
5827	+	}
5828	+	while (result.get() == null) {
5829	+	V v; U u;
5830	+	if ((v = advance()) == null) {
5831	+	propagateCompletion();
5832	+	break;
5833	+	}
5834	+	if ((u = searchFunction.apply(nextKey, v)) != null) {
5835	+	if (result.compareAndSet(null, u))
5836	+	quietlyCompleteRoot();
5837	+	break;
5838	+	}
5839	+	}
5840	+	}
5841	+	}
5842	+	}
5843	+
5844	+	@SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5845	+	extends Traverser<K,V,K> {
5846	+	final BiFunction<? super K, ? super K, ? extends K> reducer;
5847	+	K result;
5848	+	ReduceKeysTask<K,V> rights, nextRight;
5849	+	ReduceKeysTask
5850	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5851	+	ReduceKeysTask<K,V> nextRight,
5852	+	BiFunction<? super K, ? super K, ? extends K> reducer) {
5853	+	super(m, p, b); this.nextRight = nextRight;
5854	+	this.reducer = reducer;
5855	+	}
5856	+	public final K getRawResult() { return result; }
5857	+	@SuppressWarnings("unchecked") public final void compute() {
5858	+	final BiFunction<? super K, ? super K, ? extends K> reducer;
5859	+	if ((reducer = this.reducer) != null) {
5860	+	for (int b; (b = preSplit()) > 0;)
5861	+	(rights = new ReduceKeysTask<K,V>
5862	+	(map, this, b, rights, reducer)).fork();
5863	+	K r = null;
5864	+	while (advance() != null) {
5865	+	K u = nextKey;
5866	+	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5867	+	}
5868	+	result = r;
5869	+	CountedCompleter<?> c;
5870	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5871	+	ReduceKeysTask<K,V>
5872	+	t = (ReduceKeysTask<K,V>)c,
5873	+	s = t.rights;
5874	+	while (s != null) {
5875	+	K tr, sr;
5876	+	if ((sr = s.result) != null)
5877	+	t.result = (((tr = t.result) == null) ? sr :
5878	+	reducer.apply(tr, sr));
5879	+	s = t.rights = s.nextRight;
5880	+	}
5881	+	}
5882	+	}
5883	+	}
5884	+	}
5885	+
5886	+	@SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5887	+	extends Traverser<K,V,V> {
5888	+	final BiFunction<? super V, ? super V, ? extends V> reducer;
5889	+	V result;
5890	+	ReduceValuesTask<K,V> rights, nextRight;
5891	+	ReduceValuesTask
5892	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5893	+	ReduceValuesTask<K,V> nextRight,
5894	+	BiFunction<? super V, ? super V, ? extends V> reducer) {
5895	+	super(m, p, b); this.nextRight = nextRight;
5896	+	this.reducer = reducer;
5897	+	}
5898	+	public final V getRawResult() { return result; }
5899	+	@SuppressWarnings("unchecked") public final void compute() {
5900	+	final BiFunction<? super V, ? super V, ? extends V> reducer;
5901	+	if ((reducer = this.reducer) != null) {
5902	+	for (int b; (b = preSplit()) > 0;)
5903	+	(rights = new ReduceValuesTask<K,V>
5904	+	(map, this, b, rights, reducer)).fork();
5905	+	V r = null, v;
5906	+	while ((v = advance()) != null)
5907	+	r = (r == null) ? v : reducer.apply(r, v);
5908	+	result = r;
5909	+	CountedCompleter<?> c;
5910	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5911	+	ReduceValuesTask<K,V>
5912	+	t = (ReduceValuesTask<K,V>)c,
5913	+	s = t.rights;
5914	+	while (s != null) {
5915	+	V tr, sr;
5916	+	if ((sr = s.result) != null)
5917	+	t.result = (((tr = t.result) == null) ? sr :
5918	+	reducer.apply(tr, sr));
5919	+	s = t.rights = s.nextRight;
5920	+	}
5921	+	}
5922	+	}
5923	+	}
5924	+	}
5925	+
5926	+	@SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
5927	+	extends Traverser<K,V,Map.Entry<K,V>> {
5928	+	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5929	+	Map.Entry<K,V> result;
5930	+	ReduceEntriesTask<K,V> rights, nextRight;
5931	+	ReduceEntriesTask
5932	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5933	+	ReduceEntriesTask<K,V> nextRight,
5934	+	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5935	+	super(m, p, b); this.nextRight = nextRight;
5936	+	this.reducer = reducer;
5937	+	}
5938	+	public final Map.Entry<K,V> getRawResult() { return result; }
5939	+	@SuppressWarnings("unchecked") public final void compute() {
5940	+	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5941	+	if ((reducer = this.reducer) != null) {
5942	+	for (int b; (b = preSplit()) > 0;)
5943	+	(rights = new ReduceEntriesTask<K,V>
5944	+	(map, this, b, rights, reducer)).fork();
5945	+	Map.Entry<K,V> r = null;
5946	+	V v;
5947	+	while ((v = advance()) != null) {
5948	+	Map.Entry<K,V> u = entryFor(nextKey, v);
5949	+	r = (r == null) ? u : reducer.apply(r, u);
5950	+	}
5951	+	result = r;
5952	+	CountedCompleter<?> c;
5953	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5954	+	ReduceEntriesTask<K,V>
5955	+	t = (ReduceEntriesTask<K,V>)c,
5956	+	s = t.rights;
5957	+	while (s != null) {
5958	+	Map.Entry<K,V> tr, sr;
5959	+	if ((sr = s.result) != null)
5960	+	t.result = (((tr = t.result) == null) ? sr :
5961	+	reducer.apply(tr, sr));
5962	+	s = t.rights = s.nextRight;
5963	+	}
5964	+	}
5965	+	}
5966	+	}
5967	+	}
5968	+
5969	+	@SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
5970	+	extends Traverser<K,V,U> {
5971	+	final Function<? super K, ? extends U> transformer;
5972	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
5973	+	U result;
5974	+	MapReduceKeysTask<K,V,U> rights, nextRight;
5975	+	MapReduceKeysTask
5976	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5977	+	MapReduceKeysTask<K,V,U> nextRight,
5978	+	Function<? super K, ? extends U> transformer,
5979	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
5980	+	super(m, p, b); this.nextRight = nextRight;
5981	+	this.transformer = transformer;
5982	+	this.reducer = reducer;
5983	+	}
5984	+	public final U getRawResult() { return result; }
5985	+	@SuppressWarnings("unchecked") public final void compute() {
5986	+	final Function<? super K, ? extends U> transformer;
5987	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
5988	+	if ((transformer = this.transformer) != null &&
5989	+	(reducer = this.reducer) != null) {
5990	+	for (int b; (b = preSplit()) > 0;)
5991	+	(rights = new MapReduceKeysTask<K,V,U>
5992	+	(map, this, b, rights, transformer, reducer)).fork();
5993	+	U r = null, u;
5994	+	while (advance() != null) {
5995	+	if ((u = transformer.apply(nextKey)) != null)
5996	+	r = (r == null) ? u : reducer.apply(r, u);
5997	+	}
5998	+	result = r;
5999	+	CountedCompleter<?> c;
6000	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6001	+	MapReduceKeysTask<K,V,U>
6002	+	t = (MapReduceKeysTask<K,V,U>)c,
6003	+	s = t.rights;
6004	+	while (s != null) {
6005	+	U tr, sr;
6006	+	if ((sr = s.result) != null)
6007	+	t.result = (((tr = t.result) == null) ? sr :
6008	+	reducer.apply(tr, sr));
6009	+	s = t.rights = s.nextRight;
6010	+	}
6011	+	}
6012	+	}
6013	+	}
6014	+	}
6015	+
6016	+	@SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
6017	+	extends Traverser<K,V,U> {
6018	+	final Function<? super V, ? extends U> transformer;
6019	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
6020	+	U result;
6021	+	MapReduceValuesTask<K,V,U> rights, nextRight;
6022	+	MapReduceValuesTask
6023	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6024	+	MapReduceValuesTask<K,V,U> nextRight,
6025	+	Function<? super V, ? extends U> transformer,
6026	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
6027	+	super(m, p, b); this.nextRight = nextRight;
6028	+	this.transformer = transformer;
6029	+	this.reducer = reducer;
6030	+	}
6031	+	public final U getRawResult() { return result; }
6032	+	@SuppressWarnings("unchecked") public final void compute() {
6033	+	final Function<? super V, ? extends U> transformer;
6034	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
6035	+	if ((transformer = this.transformer) != null &&
6036	+	(reducer = this.reducer) != null) {
6037	+	for (int b; (b = preSplit()) > 0;)
6038	+	(rights = new MapReduceValuesTask<K,V,U>
6039	+	(map, this, b, rights, transformer, reducer)).fork();
6040	+	U r = null, u;
6041	+	V v;
6042	+	while ((v = advance()) != null) {
6043	+	if ((u = transformer.apply(v)) != null)
6044	+	r = (r == null) ? u : reducer.apply(r, u);
6045	+	}
6046	+	result = r;
6047	+	CountedCompleter<?> c;
6048	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6049	+	MapReduceValuesTask<K,V,U>
6050	+	t = (MapReduceValuesTask<K,V,U>)c,
6051	+	s = t.rights;
6052	+	while (s != null) {
6053	+	U tr, sr;
6054	+	if ((sr = s.result) != null)
6055	+	t.result = (((tr = t.result) == null) ? sr :
6056	+	reducer.apply(tr, sr));
6057	+	s = t.rights = s.nextRight;
6058	+	}
6059	+	}
6060	+	}
6061	+	}
6062	+	}
6063	+
6064	+	@SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
6065	+	extends Traverser<K,V,U> {
6066	+	final Function<Map.Entry<K,V>, ? extends U> transformer;
6067	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
6068	+	U result;
6069	+	MapReduceEntriesTask<K,V,U> rights, nextRight;
6070	+	MapReduceEntriesTask
6071	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6072	+	MapReduceEntriesTask<K,V,U> nextRight,
6073	+	Function<Map.Entry<K,V>, ? extends U> transformer,
6074	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
6075	+	super(m, p, b); this.nextRight = nextRight;
6076	+	this.transformer = transformer;
6077	+	this.reducer = reducer;
6078	+	}
6079	+	public final U getRawResult() { return result; }
6080	+	@SuppressWarnings("unchecked") public final void compute() {
6081	+	final Function<Map.Entry<K,V>, ? extends U> transformer;
6082	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
6083	+	if ((transformer = this.transformer) != null &&
6084	+	(reducer = this.reducer) != null) {
6085	+	for (int b; (b = preSplit()) > 0;)
6086	+	(rights = new MapReduceEntriesTask<K,V,U>
6087	+	(map, this, b, rights, transformer, reducer)).fork();
6088	+	U r = null, u;
6089	+	V v;
6090	+	while ((v = advance()) != null) {
6091	+	if ((u = transformer.apply(entryFor(nextKey,
6092	+	v))) != null)
6093	+	r = (r == null) ? u : reducer.apply(r, u);
6094	+	}
6095	+	result = r;
6096	+	CountedCompleter<?> c;
6097	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6098	+	MapReduceEntriesTask<K,V,U>
6099	+	t = (MapReduceEntriesTask<K,V,U>)c,
6100	+	s = t.rights;
6101	+	while (s != null) {
6102	+	U tr, sr;
6103	+	if ((sr = s.result) != null)
6104	+	t.result = (((tr = t.result) == null) ? sr :
6105	+	reducer.apply(tr, sr));
6106	+	s = t.rights = s.nextRight;
6107	+	}
6108	+	}
6109	+	}
6110	+	}
6111	+	}
6112	+
6113	+	@SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
6114	+	extends Traverser<K,V,U> {
6115	+	final BiFunction<? super K, ? super V, ? extends U> transformer;
6116	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
6117	+	U result;
6118	+	MapReduceMappingsTask<K,V,U> rights, nextRight;
6119	+	MapReduceMappingsTask
6120	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6121	+	MapReduceMappingsTask<K,V,U> nextRight,
6122	+	BiFunction<? super K, ? super V, ? extends U> transformer,
6123	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
6124	+	super(m, p, b); this.nextRight = nextRight;
6125	+	this.transformer = transformer;
6126	+	this.reducer = reducer;
6127	+	}
6128	+	public final U getRawResult() { return result; }
6129	+	@SuppressWarnings("unchecked") public final void compute() {
6130	+	final BiFunction<? super K, ? super V, ? extends U> transformer;
6131	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
6132	+	if ((transformer = this.transformer) != null &&
6133	+	(reducer = this.reducer) != null) {
6134	+	for (int b; (b = preSplit()) > 0;)
6135	+	(rights = new MapReduceMappingsTask<K,V,U>
6136	+	(map, this, b, rights, transformer, reducer)).fork();
6137	+	U r = null, u;
6138	+	V v;
6139	+	while ((v = advance()) != null) {
6140	+	if ((u = transformer.apply(nextKey, v)) != null)
6141	+	r = (r == null) ? u : reducer.apply(r, u);
6142	+	}
6143	+	result = r;
6144	+	CountedCompleter<?> c;
6145	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6146	+	MapReduceMappingsTask<K,V,U>
6147	+	t = (MapReduceMappingsTask<K,V,U>)c,
6148	+	s = t.rights;
6149	+	while (s != null) {
6150	+	U tr, sr;
6151	+	if ((sr = s.result) != null)
6152	+	t.result = (((tr = t.result) == null) ? sr :
6153	+	reducer.apply(tr, sr));
6154	+	s = t.rights = s.nextRight;
6155	+	}
6156	+	}
6157	+	}
6158	+	}
6159	+	}
6160	+
6161	+	@SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
6162	+	extends Traverser<K,V,Double> {
6163	+	final DoubleFunction<? super K> transformer;
6164	+	final DoubleBinaryOperator reducer;
6165	+	final double basis;
6166	+	double result;
6167	+	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
6168	+	MapReduceKeysToDoubleTask
6169	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6170	+	MapReduceKeysToDoubleTask<K,V> nextRight,
6171	+	DoubleFunction<? super K> transformer,
6172	+	double basis,
6173	+	DoubleBinaryOperator reducer) {
6174	+	super(m, p, b); this.nextRight = nextRight;
6175	+	this.transformer = transformer;
6176	+	this.basis = basis; this.reducer = reducer;
6177	+	}
6178	+	public final Double getRawResult() { return result; }
6179	+	@SuppressWarnings("unchecked") public final void compute() {
6180	+	final DoubleFunction<? super K> transformer;
6181	+	final DoubleBinaryOperator reducer;
6182	+	if ((transformer = this.transformer) != null &&
6183	+	(reducer = this.reducer) != null) {
6184	+	double r = this.basis;
6185	+	for (int b; (b = preSplit()) > 0;)
6186	+	(rights = new MapReduceKeysToDoubleTask<K,V>
6187	+	(map, this, b, rights, transformer, r, reducer)).fork();
6188	+	while (advance() != null)
6189	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(nextKey));
6190	+	result = r;
6191	+	CountedCompleter<?> c;
6192	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6193	+	MapReduceKeysToDoubleTask<K,V>
6194	+	t = (MapReduceKeysToDoubleTask<K,V>)c,
6195	+	s = t.rights;
6196	+	while (s != null) {
6197	+	t.result = reducer.applyAsDouble(t.result, s.result);
6198	+	s = t.rights = s.nextRight;
6199	+	}
6200	+	}
6201	+	}
6202	+	}
6203	+	}
6204	+
6205	+	@SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
6206	+	extends Traverser<K,V,Double> {
6207	+	final DoubleFunction<? super V> transformer;
6208	+	final DoubleBinaryOperator reducer;
6209	+	final double basis;
6210	+	double result;
6211	+	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
6212	+	MapReduceValuesToDoubleTask
6213	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6214	+	MapReduceValuesToDoubleTask<K,V> nextRight,
6215	+	DoubleFunction<? super V> transformer,
6216	+	double basis,
6217	+	DoubleBinaryOperator reducer) {
6218	+	super(m, p, b); this.nextRight = nextRight;
6219	+	this.transformer = transformer;
6220	+	this.basis = basis; this.reducer = reducer;
6221	+	}
6222	+	public final Double getRawResult() { return result; }
6223	+	@SuppressWarnings("unchecked") public final void compute() {
6224	+	final DoubleFunction<? super V> transformer;
6225	+	final DoubleBinaryOperator reducer;
6226	+	if ((transformer = this.transformer) != null &&
6227	+	(reducer = this.reducer) != null) {
6228	+	double r = this.basis;
6229	+	for (int b; (b = preSplit()) > 0;)
6230	+	(rights = new MapReduceValuesToDoubleTask<K,V>
6231	+	(map, this, b, rights, transformer, r, reducer)).fork();
6232	+	V v;
6233	+	while ((v = advance()) != null)
6234	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
6235	+	result = r;
6236	+	CountedCompleter<?> c;
6237	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6238	+	MapReduceValuesToDoubleTask<K,V>
6239	+	t = (MapReduceValuesToDoubleTask<K,V>)c,
6240	+	s = t.rights;
6241	+	while (s != null) {
6242	+	t.result = reducer.applyAsDouble(t.result, s.result);
6243	+	s = t.rights = s.nextRight;
6244	+	}
6245	+	}
6246	+	}
6247	+	}
6248	+	}
6249	+
6250	+	@SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6251	+	extends Traverser<K,V,Double> {
6252	+	final DoubleFunction<Map.Entry<K,V>> transformer;
6253	+	final DoubleBinaryOperator reducer;
6254	+	final double basis;
6255	+	double result;
6256	+	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6257	+	MapReduceEntriesToDoubleTask
6258	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6259	+	MapReduceEntriesToDoubleTask<K,V> nextRight,
6260	+	DoubleFunction<Map.Entry<K,V>> transformer,
6261	+	double basis,
6262	+	DoubleBinaryOperator reducer) {
6263	+	super(m, p, b); this.nextRight = nextRight;
6264	+	this.transformer = transformer;
6265	+	this.basis = basis; this.reducer = reducer;
6266	+	}
6267	+	public final Double getRawResult() { return result; }
6268	+	@SuppressWarnings("unchecked") public final void compute() {
6269	+	final DoubleFunction<Map.Entry<K,V>> transformer;
6270	+	final DoubleBinaryOperator reducer;
6271	+	if ((transformer = this.transformer) != null &&
6272	+	(reducer = this.reducer) != null) {
6273	+	double r = this.basis;
6274	+	for (int b; (b = preSplit()) > 0;)
6275	+	(rights = new MapReduceEntriesToDoubleTask<K,V>
6276	+	(map, this, b, rights, transformer, r, reducer)).fork();
6277	+	V v;
6278	+	while ((v = advance()) != null)
6279	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor(nextKey,
6280	+	v)));
6281	+	result = r;
6282	+	CountedCompleter<?> c;
6283	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6284	+	MapReduceEntriesToDoubleTask<K,V>
6285	+	t = (MapReduceEntriesToDoubleTask<K,V>)c,
6286	+	s = t.rights;
6287	+	while (s != null) {
6288	+	t.result = reducer.applyAsDouble(t.result, s.result);
6289	+	s = t.rights = s.nextRight;
6290	+	}
6291	+	}
6292	+	}
6293	+	}
6294	+	}
6295	+
6296	+	@SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6297	+	extends Traverser<K,V,Double> {
6298	+	final DoubleBiFunction<? super K, ? super V> transformer;
6299	+	final DoubleBinaryOperator reducer;
6300	+	final double basis;
6301	+	double result;
6302	+	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6303	+	MapReduceMappingsToDoubleTask
6304	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6305	+	MapReduceMappingsToDoubleTask<K,V> nextRight,
6306	+	DoubleBiFunction<? super K, ? super V> transformer,
6307	+	double basis,
6308	+	DoubleBinaryOperator reducer) {
6309	+	super(m, p, b); this.nextRight = nextRight;
6310	+	this.transformer = transformer;
6311	+	this.basis = basis; this.reducer = reducer;
6312	+	}
6313	+	public final Double getRawResult() { return result; }
6314	+	@SuppressWarnings("unchecked") public final void compute() {
6315	+	final DoubleBiFunction<? super K, ? super V> transformer;
6316	+	final DoubleBinaryOperator reducer;
6317	+	if ((transformer = this.transformer) != null &&
6318	+	(reducer = this.reducer) != null) {
6319	+	double r = this.basis;
6320	+	for (int b; (b = preSplit()) > 0;)
6321	+	(rights = new MapReduceMappingsToDoubleTask<K,V>
6322	+	(map, this, b, rights, transformer, r, reducer)).fork();
6323	+	V v;
6324	+	while ((v = advance()) != null)
6325	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(nextKey, v));
6326	+	result = r;
6327	+	CountedCompleter<?> c;
6328	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6329	+	MapReduceMappingsToDoubleTask<K,V>
6330	+	t = (MapReduceMappingsToDoubleTask<K,V>)c,
6331	+	s = t.rights;
6332	+	while (s != null) {
6333	+	t.result = reducer.applyAsDouble(t.result, s.result);
6334	+	s = t.rights = s.nextRight;
6335	+	}
6336	+	}
6337	+	}
6338	+	}
6339	+	}
6340	+
6341	+	@SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6342	+	extends Traverser<K,V,Long> {
6343	+	final LongFunction<? super K> transformer;
6344	+	final LongBinaryOperator reducer;
6345	+	final long basis;
6346	+	long result;
6347	+	MapReduceKeysToLongTask<K,V> rights, nextRight;
6348	+	MapReduceKeysToLongTask
6349	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6350	+	MapReduceKeysToLongTask<K,V> nextRight,
6351	+	LongFunction<? super K> transformer,
6352	+	long basis,
6353	+	LongBinaryOperator reducer) {
6354	+	super(m, p, b); this.nextRight = nextRight;
6355	+	this.transformer = transformer;
6356	+	this.basis = basis; this.reducer = reducer;
6357	+	}
6358	+	public final Long getRawResult() { return result; }
6359	+	@SuppressWarnings("unchecked") public final void compute() {
6360	+	final LongFunction<? super K> transformer;
6361	+	final LongBinaryOperator reducer;
6362	+	if ((transformer = this.transformer) != null &&
6363	+	(reducer = this.reducer) != null) {
6364	+	long r = this.basis;
6365	+	for (int b; (b = preSplit()) > 0;)
6366	+	(rights = new MapReduceKeysToLongTask<K,V>
6367	+	(map, this, b, rights, transformer, r, reducer)).fork();
6368	+	while (advance() != null)
6369	+	r = reducer.applyAsLong(r, transformer.applyAsLong(nextKey));
6370	+	result = r;
6371	+	CountedCompleter<?> c;
6372	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6373	+	MapReduceKeysToLongTask<K,V>
6374	+	t = (MapReduceKeysToLongTask<K,V>)c,
6375	+	s = t.rights;
6376	+	while (s != null) {
6377	+	t.result = reducer.applyAsLong(t.result, s.result);
6378	+	s = t.rights = s.nextRight;
6379	+	}
6380	+	}
6381	+	}
6382	+	}
6383	+	}
6384	+
6385	+	@SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6386	+	extends Traverser<K,V,Long> {
6387	+	final LongFunction<? super V> transformer;
6388	+	final LongBinaryOperator reducer;
6389	+	final long basis;
6390	+	long result;
6391	+	MapReduceValuesToLongTask<K,V> rights, nextRight;
6392	+	MapReduceValuesToLongTask
6393	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6394	+	MapReduceValuesToLongTask<K,V> nextRight,
6395	+	LongFunction<? super V> transformer,
6396	+	long basis,
6397	+	LongBinaryOperator reducer) {
6398	+	super(m, p, b); this.nextRight = nextRight;
6399	+	this.transformer = transformer;
6400	+	this.basis = basis; this.reducer = reducer;
6401	+	}
6402	+	public final Long getRawResult() { return result; }
6403	+	@SuppressWarnings("unchecked") public final void compute() {
6404	+	final LongFunction<? super V> transformer;
6405	+	final LongBinaryOperator reducer;
6406	+	if ((transformer = this.transformer) != null &&
6407	+	(reducer = this.reducer) != null) {
6408	+	long r = this.basis;
6409	+	for (int b; (b = preSplit()) > 0;)
6410	+	(rights = new MapReduceValuesToLongTask<K,V>
6411	+	(map, this, b, rights, transformer, r, reducer)).fork();
6412	+	V v;
6413	+	while ((v = advance()) != null)
6414	+	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
6415	+	result = r;
6416	+	CountedCompleter<?> c;
6417	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6418	+	MapReduceValuesToLongTask<K,V>
6419	+	t = (MapReduceValuesToLongTask<K,V>)c,
6420	+	s = t.rights;
6421	+	while (s != null) {
6422	+	t.result = reducer.applyAsLong(t.result, s.result);
6423	+	s = t.rights = s.nextRight;
6424	+	}
6425	+	}
6426	+	}
6427	+	}
6428	+	}
6429	+
6430	+	@SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6431	+	extends Traverser<K,V,Long> {
6432	+	final LongFunction<Map.Entry<K,V>> transformer;
6433	+	final LongBinaryOperator reducer;
6434	+	final long basis;
6435	+	long result;
6436	+	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6437	+	MapReduceEntriesToLongTask
6438	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6439	+	MapReduceEntriesToLongTask<K,V> nextRight,
6440	+	LongFunction<Map.Entry<K,V>> transformer,
6441	+	long basis,
6442	+	LongBinaryOperator reducer) {
6443	+	super(m, p, b); this.nextRight = nextRight;
6444	+	this.transformer = transformer;
6445	+	this.basis = basis; this.reducer = reducer;
6446	+	}
6447	+	public final Long getRawResult() { return result; }
6448	+	@SuppressWarnings("unchecked") public final void compute() {
6449	+	final LongFunction<Map.Entry<K,V>> transformer;
6450	+	final LongBinaryOperator reducer;
6451	+	if ((transformer = this.transformer) != null &&
6452	+	(reducer = this.reducer) != null) {
6453	+	long r = this.basis;
6454	+	for (int b; (b = preSplit()) > 0;)
6455	+	(rights = new MapReduceEntriesToLongTask<K,V>
6456	+	(map, this, b, rights, transformer, r, reducer)).fork();
6457	+	V v;
6458	+	while ((v = advance()) != null)
6459	+	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor(nextKey, v)));
6460	+	result = r;
6461	+	CountedCompleter<?> c;
6462	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6463	+	MapReduceEntriesToLongTask<K,V>
6464	+	t = (MapReduceEntriesToLongTask<K,V>)c,
6465	+	s = t.rights;
6466	+	while (s != null) {
6467	+	t.result = reducer.applyAsLong(t.result, s.result);
6468	+	s = t.rights = s.nextRight;
6469	+	}
6470	+	}
6471	+	}
6472	+	}
6473	+	}
6474	+
6475	+	@SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6476	+	extends Traverser<K,V,Long> {
6477	+	final LongBiFunction<? super K, ? super V> transformer;
6478	+	final LongBinaryOperator reducer;
6479	+	final long basis;
6480	+	long result;
6481	+	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6482	+	MapReduceMappingsToLongTask
6483	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6484	+	MapReduceMappingsToLongTask<K,V> nextRight,
6485	+	LongBiFunction<? super K, ? super V> transformer,
6486	+	long basis,
6487	+	LongBinaryOperator reducer) {
6488	+	super(m, p, b); this.nextRight = nextRight;
6489	+	this.transformer = transformer;
6490	+	this.basis = basis; this.reducer = reducer;
6491	+	}
6492	+	public final Long getRawResult() { return result; }
6493	+	@SuppressWarnings("unchecked") public final void compute() {
6494	+	final LongBiFunction<? super K, ? super V> transformer;
6495	+	final LongBinaryOperator reducer;
6496	+	if ((transformer = this.transformer) != null &&
6497	+	(reducer = this.reducer) != null) {
6498	+	long r = this.basis;
6499	+	for (int b; (b = preSplit()) > 0;)
6500	+	(rights = new MapReduceMappingsToLongTask<K,V>
6501	+	(map, this, b, rights, transformer, r, reducer)).fork();
6502	+	V v;
6503	+	while ((v = advance()) != null)
6504	+	r = reducer.applyAsLong(r, transformer.applyAsLong(nextKey, v));
6505	+	result = r;
6506	+	CountedCompleter<?> c;
6507	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6508	+	MapReduceMappingsToLongTask<K,V>
6509	+	t = (MapReduceMappingsToLongTask<K,V>)c,
6510	+	s = t.rights;
6511	+	while (s != null) {
6512	+	t.result = reducer.applyAsLong(t.result, s.result);
6513	+	s = t.rights = s.nextRight;
6514	+	}
6515	+	}
6516	+	}
6517	+	}
6518	+	}
6519	+
6520	+	@SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6521	+	extends Traverser<K,V,Integer> {
6522	+	final IntFunction<? super K> transformer;
6523	+	final IntBinaryOperator reducer;
6524	+	final int basis;
6525	+	int result;
6526	+	MapReduceKeysToIntTask<K,V> rights, nextRight;
6527	+	MapReduceKeysToIntTask
6528	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6529	+	MapReduceKeysToIntTask<K,V> nextRight,
6530	+	IntFunction<? super K> transformer,
6531	+	int basis,
6532	+	IntBinaryOperator reducer) {
6533	+	super(m, p, b); this.nextRight = nextRight;
6534	+	this.transformer = transformer;
6535	+	this.basis = basis; this.reducer = reducer;
6536	+	}
6537	+	public final Integer getRawResult() { return result; }
6538	+	@SuppressWarnings("unchecked") public final void compute() {
6539	+	final IntFunction<? super K> transformer;
6540	+	final IntBinaryOperator reducer;
6541	+	if ((transformer = this.transformer) != null &&
6542	+	(reducer = this.reducer) != null) {
6543	+	int r = this.basis;
6544	+	for (int b; (b = preSplit()) > 0;)
6545	+	(rights = new MapReduceKeysToIntTask<K,V>
6546	+	(map, this, b, rights, transformer, r, reducer)).fork();
6547	+	while (advance() != null)
6548	+	r = reducer.applyAsInt(r, transformer.applyAsInt(nextKey));
6549	+	result = r;
6550	+	CountedCompleter<?> c;
6551	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6552	+	MapReduceKeysToIntTask<K,V>
6553	+	t = (MapReduceKeysToIntTask<K,V>)c,
6554	+	s = t.rights;
6555	+	while (s != null) {
6556	+	t.result = reducer.applyAsInt(t.result, s.result);
6557	+	s = t.rights = s.nextRight;
6558	+	}
6559	+	}
6560	+	}
6561	+	}
6562	+	}
6563	+
6564	+	@SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6565	+	extends Traverser<K,V,Integer> {
6566	+	final IntFunction<? super V> transformer;
6567	+	final IntBinaryOperator reducer;
6568	+	final int basis;
6569	+	int result;
6570	+	MapReduceValuesToIntTask<K,V> rights, nextRight;
6571	+	MapReduceValuesToIntTask
6572	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6573	+	MapReduceValuesToIntTask<K,V> nextRight,
6574	+	IntFunction<? super V> transformer,
6575	+	int basis,
6576	+	IntBinaryOperator reducer) {
6577	+	super(m, p, b); this.nextRight = nextRight;
6578	+	this.transformer = transformer;
6579	+	this.basis = basis; this.reducer = reducer;
6580	+	}
6581	+	public final Integer getRawResult() { return result; }
6582	+	@SuppressWarnings("unchecked") public final void compute() {
6583	+	final IntFunction<? super V> transformer;
6584	+	final IntBinaryOperator reducer;
6585	+	if ((transformer = this.transformer) != null &&
6586	+	(reducer = this.reducer) != null) {
6587	+	int r = this.basis;
6588	+	for (int b; (b = preSplit()) > 0;)
6589	+	(rights = new MapReduceValuesToIntTask<K,V>
6590	+	(map, this, b, rights, transformer, r, reducer)).fork();
6591	+	V v;
6592	+	while ((v = advance()) != null)
6593	+	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
6594	+	result = r;
6595	+	CountedCompleter<?> c;
6596	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6597	+	MapReduceValuesToIntTask<K,V>
6598	+	t = (MapReduceValuesToIntTask<K,V>)c,
6599	+	s = t.rights;
6600	+	while (s != null) {
6601	+	t.result = reducer.applyAsInt(t.result, s.result);
6602	+	s = t.rights = s.nextRight;
6603	+	}
6604	+	}
6605	+	}
6606	+	}
6607	+	}
6608	+
6609	+	@SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6610	+	extends Traverser<K,V,Integer> {
6611	+	final IntFunction<Map.Entry<K,V>> transformer;
6612	+	final IntBinaryOperator reducer;
6613	+	final int basis;
6614	+	int result;
6615	+	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6616	+	MapReduceEntriesToIntTask
6617	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6618	+	MapReduceEntriesToIntTask<K,V> nextRight,
6619	+	IntFunction<Map.Entry<K,V>> transformer,
6620	+	int basis,
6621	+	IntBinaryOperator reducer) {
6622	+	super(m, p, b); this.nextRight = nextRight;
6623	+	this.transformer = transformer;
6624	+	this.basis = basis; this.reducer = reducer;
6625	+	}
6626	+	public final Integer getRawResult() { return result; }
6627	+	@SuppressWarnings("unchecked") public final void compute() {
6628	+	final IntFunction<Map.Entry<K,V>> transformer;
6629	+	final IntBinaryOperator reducer;
6630	+	if ((transformer = this.transformer) != null &&
6631	+	(reducer = this.reducer) != null) {
6632	+	int r = this.basis;
6633	+	for (int b; (b = preSplit()) > 0;)
6634	+	(rights = new MapReduceEntriesToIntTask<K,V>
6635	+	(map, this, b, rights, transformer, r, reducer)).fork();
6636	+	V v;
6637	+	while ((v = advance()) != null)
6638	+	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor(nextKey,
6639	+	v)));
6640	+	result = r;
6641	+	CountedCompleter<?> c;
6642	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6643	+	MapReduceEntriesToIntTask<K,V>
6644	+	t = (MapReduceEntriesToIntTask<K,V>)c,
6645	+	s = t.rights;
6646	+	while (s != null) {
6647	+	t.result = reducer.applyAsInt(t.result, s.result);
6648	+	s = t.rights = s.nextRight;
6649	+	}
6650	+	}
6651	+	}
6652	+	}
6653	+	}
6654	+
6655	+	@SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6656	+	extends Traverser<K,V,Integer> {
6657	+	final IntBiFunction<? super K, ? super V> transformer;
6658	+	final IntBinaryOperator reducer;
6659	+	final int basis;
6660	+	int result;
6661	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6662	+	MapReduceMappingsToIntTask
6663	+	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6664	+	MapReduceMappingsToIntTask<K,V> nextRight,
6665	+	IntBiFunction<? super K, ? super V> transformer,
6666	+	int basis,
6667	+	IntBinaryOperator reducer) {
6668	+	super(m, p, b); this.nextRight = nextRight;
6669	+	this.transformer = transformer;
6670	+	this.basis = basis; this.reducer = reducer;
6671	+	}
6672	+	public final Integer getRawResult() { return result; }
6673	+	@SuppressWarnings("unchecked") public final void compute() {
6674	+	final IntBiFunction<? super K, ? super V> transformer;
6675	+	final IntBinaryOperator reducer;
6676	+	if ((transformer = this.transformer) != null &&
6677	+	(reducer = this.reducer) != null) {
6678	+	int r = this.basis;
6679	+	for (int b; (b = preSplit()) > 0;)
6680	+	(rights = new MapReduceMappingsToIntTask<K,V>
6681	+	(map, this, b, rights, transformer, r, reducer)).fork();
6682	+	V v;
6683	+	while ((v = advance()) != null)
6684	+	r = reducer.applyAsInt(r, transformer.applyAsInt(nextKey, v));
6685	+	result = r;
6686	+	CountedCompleter<?> c;
6687	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6688	+	MapReduceMappingsToIntTask<K,V>
6689	+	t = (MapReduceMappingsToIntTask<K,V>)c,
6690	+	s = t.rights;
6691	+	while (s != null) {
6692	+	t.result = reducer.applyAsInt(t.result, s.result);
6693	+	s = t.rights = s.nextRight;
6694	+	}
6695	+	}
6696	+	}
6697	+	}
6698	+	}
6699	+
6700	+	// Unsafe mechanics
6701	+	private static final sun.misc.Unsafe U;
6702	+	private static final long SIZECTL;
6703	+	private static final long TRANSFERINDEX;
6704	+	private static final long TRANSFERORIGIN;
6705	+	private static final long BASECOUNT;
6706	+	private static final long CELLSBUSY;
6707	+	private static final long CELLVALUE;
6708	+	private static final long ABASE;
6709	+	private static final int ASHIFT;
6710	+
6711	+	static {
6712	+	try {
6713	+	U = sun.misc.Unsafe.getUnsafe();
6714	+	Class<?> k = ConcurrentHashMap.class;
6715	+	SIZECTL = U.objectFieldOffset
6716	+	(k.getDeclaredField("sizeCtl"));
6717	+	TRANSFERINDEX = U.objectFieldOffset
6718	+	(k.getDeclaredField("transferIndex"));
6719	+	TRANSFERORIGIN = U.objectFieldOffset
6720	+	(k.getDeclaredField("transferOrigin"));
6721	+	BASECOUNT = U.objectFieldOffset
6722	+	(k.getDeclaredField("baseCount"));
6723	+	CELLSBUSY = U.objectFieldOffset
6724	+	(k.getDeclaredField("cellsBusy"));
6725	+	Class<?> ck = Cell.class;
6726	+	CELLVALUE = U.objectFieldOffset
6727	+	(ck.getDeclaredField("value"));
6728	+	Class<?> sc = Node[].class;
6729	+	ABASE = U.arrayBaseOffset(sc);
6730	+	int scale = U.arrayIndexScale(sc);
6731	+	if ((scale & (scale - 1)) != 0)
6732	+	throw new Error("data type scale not a power of two");
6733	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6734	+	} catch (Exception e) {
6735	+	throw new Error(e);
6736	+	}
6737	+	}
6738	+
6739	+	}

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