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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.24 by dl, Fri Oct 10 23:51:28 2003 UTC vs.
Revision 1.296 by dl, Sun Jul 17 12:09:12 2016 UTC

#	Line 1 | Line 1
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	>
9	>	import java.io.ObjectStreamField;
10		import java.io.Serializable;
11	<	import java.io.IOException;
12	<	import java.io.ObjectInputStream;
13	<	import java.io.ObjectOutputStream;
11	>	import java.lang.reflect.ParameterizedType;
12	>	import java.lang.reflect.Type;
13	>	import java.util.AbstractMap;
14	>	import java.util.Arrays;
15	>	import java.util.Collection;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.atomic.AtomicReference;
25	>	import java.util.concurrent.locks.LockSupport;
26	>	import java.util.concurrent.locks.ReentrantLock;
27	>	import java.util.function.BiConsumer;
28	>	import java.util.function.BiFunction;
29	>	import java.util.function.Consumer;
30	>	import java.util.function.DoubleBinaryOperator;
31	>	import java.util.function.Function;
32	>	import java.util.function.IntBinaryOperator;
33	>	import java.util.function.LongBinaryOperator;
34	>	import java.util.function.Predicate;
35	>	import java.util.function.ToDoubleBiFunction;
36	>	import java.util.function.ToDoubleFunction;
37	>	import java.util.function.ToIntBiFunction;
38	>	import java.util.function.ToIntFunction;
39	>	import java.util.function.ToLongBiFunction;
40	>	import java.util.function.ToLongFunction;
41	>	import java.util.stream.Stream;
42	>	import jdk.internal.misc.Unsafe;
43
44		/**
45		* A hash table supporting full concurrency of retrievals and
46	<	* adjustable expected concurrency for updates. This class obeys the
46	>	* high expected concurrency for updates. This class obeys the
47		* same functional specification as {@link java.util.Hashtable}, and
48		* includes versions of methods corresponding to each method of
49	<	* <tt>Hashtable</tt> . However, even though all operations are
49	>	* {@code Hashtable}. However, even though all operations are
50		* thread-safe, retrieval operations do <em>not</em> entail locking,
51		* and there is <em>not</em> any support for locking the entire table
52		* in a way that prevents all access.  This class is fully
53	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
53	>	* interoperable with {@code Hashtable} in programs that rely on its
54		* thread safety but not on its synchronization details.
55		*
56	<	* <p> Retrieval operations (including <tt>get</tt>) ordinarily
57	<	* overlap with update operations (including <tt>put</tt> and
58	<	* <tt>remove</tt>). Retrievals reflect the results of the most
56	>	* <p>Retrieval operations (including {@code get}) generally do not
57	>	* block, so may overlap with update operations (including {@code put}
58	>	* and {@code remove}). Retrievals reflect the results of the most
59		* recently <em>completed</em> update operations holding upon their
60	<	* onset.  For aggregate operations such as <tt>putAll</tt> and
61	<	* <tt>clear</tt>, concurrent retrievals may reflect insertion or
62	<	* removal of only some entries.  Similarly, Iterators and
63	<	* Enumerations return elements reflecting the state of the hash table
64	<	* at some point at or since the creation of the iterator/enumeration.
65	<	* They do <em>not</em> throw <tt>ConcurrentModificationException</tt>.
66	<	* However, Iterators are designed to be used by only one thread at a
67	<	* time.
68	<	*
69	<	* <p> The allowed concurrency among update operations is guided by
70	<	* the optional <tt>concurrencyLevel</tt> constructor argument
71	<	* (default 16), which is used as a hint for internal sizing.  The
72	<	* table is internally partitioned to try to permit the indicated
73	<	* number of concurrent updates without contention. Because placement
74	<	* in hash tables is essentially random, the actual concurrency will
75	<	* vary.  Ideally, you should choose a value to accommodate as many
76	<	* threads as will ever concurrently access the table. Using a
77	<	* significantly higher value than you need can waste space and time,
78	<	* and a significantly lower value can lead to thread contention. But
79	<	* overestimates and underestimates within an order of magnitude do
80	<	* not usually have much noticeable impact.
81	<	*
82	<	* <p>This class implements all of the <em>optional</em> methods
83	<	* of the {@link Map} and {@link Iterator} interfaces.
84	<	*
85	<	* <p> Like {@link java.util.Hashtable} but unlike {@link
86	<	* java.util.HashMap}, this class does NOT allow <tt>null</tt> to be
87	<	* used as a key or value.
60	>	* onset. (More formally, an update operation for a given key bears a
61	>	* <em>happens-before</em> relation with any (non-null) retrieval for
62	>	* that key reporting the updated value.)  For aggregate operations
63	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
64	>	* reflect insertion or removal of only some entries.  Similarly,
65	>	* Iterators, Spliterators and Enumerations return elements reflecting the
66	>	* state of the hash table at some point at or since the creation of the
67	>	* iterator/enumeration.  They do <em>not</em> throw {@link
68	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
69	>	* However, iterators are designed to be used by only one thread at a time.
70	>	* Bear in mind that the results of aggregate status methods including
71	>	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
72	>	* useful only when a map is not undergoing concurrent updates in other threads.
73	>	* Otherwise the results of these methods reflect transient states
74	>	* that may be adequate for monitoring or estimation purposes, but not
75	>	* for program control.
76	>	*
77	>	* <p>The table is dynamically expanded when there are too many
78	>	* collisions (i.e., keys that have distinct hash codes but fall into
79	>	* the same slot modulo the table size), with the expected average
80	>	* effect of maintaining roughly two bins per mapping (corresponding
81	>	* to a 0.75 load factor threshold for resizing). There may be much
82	>	* variance around this average as mappings are added and removed, but
83	>	* overall, this maintains a commonly accepted time/space tradeoff for
84	>	* hash tables.  However, resizing this or any other kind of hash
85	>	* table may be a relatively slow operation. When possible, it is a
86	>	* good idea to provide a size estimate as an optional {@code
87	>	* initialCapacity} constructor argument. An additional optional
88	>	* {@code loadFactor} constructor argument provides a further means of
89	>	* customizing initial table capacity by specifying the table density
90	>	* to be used in calculating the amount of space to allocate for the
91	>	* given number of elements.  Also, for compatibility with previous
92	>	* versions of this class, constructors may optionally specify an
93	>	* expected {@code concurrencyLevel} as an additional hint for
94	>	* internal sizing.  Note that using many keys with exactly the same
95	>	* {@code hashCode()} is a sure way to slow down performance of any
96	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
97	>	* this class may use comparison order among keys to help break ties.
98	>	*
99	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
100	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
101	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
102	>	* mapped values are (perhaps transiently) not used or all take the
103	>	* same mapping value.
104	>	*
105	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
106	>	* form of histogram or multiset) by using {@link
107	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
108	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
109	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
110	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
111	>	*
112	>	* <p>This class and its views and iterators implement all of the
113	>	* <em>optional</em> methods of the {@link Map} and {@link Iterator}
114	>	* interfaces.
115	>	*
116	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
117	>	* does <em>not</em> allow {@code null} to be used as a key or value.
118	>	*
119	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
120	>	* operations that, unlike most {@link Stream} methods, are designed
121	>	* to be safely, and often sensibly, applied even with maps that are
122	>	* being concurrently updated by other threads; for example, when
123	>	* computing a snapshot summary of the values in a shared registry.
124	>	* There are three kinds of operation, each with four forms, accepting
125	>	* functions with keys, values, entries, and (key, value) pairs as
126	>	* arguments and/or return values. Because the elements of a
127	>	* ConcurrentHashMap are not ordered in any particular way, and may be
128	>	* processed in different orders in different parallel executions, the
129	>	* correctness of supplied functions should not depend on any
130	>	* ordering, or on any other objects or values that may transiently
131	>	* change while computation is in progress; and except for forEach
132	>	* actions, should ideally be side-effect-free. Bulk operations on
133	>	* {@link java.util.Map.Entry} objects do not support method {@code
134	>	* setValue}.
135	>	*
136	>	* <ul>
137	>	* <li>forEach: Performs a given action on each element.
138	>	* A variant form applies a given transformation on each element
139	>	* before performing the action.
140	>	*
141	>	* <li>search: Returns the first available non-null result of
142	>	* applying a given function on each element; skipping further
143	>	* search when a result is found.
144	>	*
145	>	* <li>reduce: Accumulates each element.  The supplied reduction
146	>	* function cannot rely on ordering (more formally, it should be
147	>	* both associative and commutative).  There are five variants:
148	>	*
149	>	* <ul>
150	>	*
151	>	* <li>Plain reductions. (There is not a form of this method for
152	>	* (key, value) function arguments since there is no corresponding
153	>	* return type.)
154	>	*
155	>	* <li>Mapped reductions that accumulate the results of a given
156	>	* function applied to each element.
157	>	*
158	>	* <li>Reductions to scalar doubles, longs, and ints, using a
159	>	* given basis value.
160	>	*
161	>	* </ul>
162	>	* </ul>
163	>	*
164	>	* <p>These bulk operations accept a {@code parallelismThreshold}
165	>	* argument. Methods proceed sequentially if the current map size is
166	>	* estimated to be less than the given threshold. Using a value of
167	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
168	>	* of {@code 1} results in maximal parallelism by partitioning into
169	>	* enough subtasks to fully utilize the {@link
170	>	* ForkJoinPool#commonPool()} that is used for all parallel
171	>	* computations. Normally, you would initially choose one of these
172	>	* extreme values, and then measure performance of using in-between
173	>	* values that trade off overhead versus throughput.
174	>	*
175	>	* <p>The concurrency properties of bulk operations follow
176	>	* from those of ConcurrentHashMap: Any non-null result returned
177	>	* from {@code get(key)} and related access methods bears a
178	>	* happens-before relation with the associated insertion or
179	>	* update.  The result of any bulk operation reflects the
180	>	* composition of these per-element relations (but is not
181	>	* necessarily atomic with respect to the map as a whole unless it
182	>	* is somehow known to be quiescent).  Conversely, because keys
183	>	* and values in the map are never null, null serves as a reliable
184	>	* atomic indicator of the current lack of any result.  To
185	>	* maintain this property, null serves as an implicit basis for
186	>	* all non-scalar reduction operations. For the double, long, and
187	>	* int versions, the basis should be one that, when combined with
188	>	* any other value, returns that other value (more formally, it
189	>	* should be the identity element for the reduction). Most common
190	>	* reductions have these properties; for example, computing a sum
191	>	* with basis 0 or a minimum with basis MAX_VALUE.
192	>	*
193	>	* <p>Search and transformation functions provided as arguments
194	>	* should similarly return null to indicate the lack of any result
195	>	* (in which case it is not used). In the case of mapped
196	>	* reductions, this also enables transformations to serve as
197	>	* filters, returning null (or, in the case of primitive
198	>	* specializations, the identity basis) if the element should not
199	>	* be combined. You can create compound transformations and
200	>	* filterings by composing them yourself under this "null means
201	>	* there is nothing there now" rule before using them in search or
202	>	* reduce operations.
203	>	*
204	>	* <p>Methods accepting and/or returning Entry arguments maintain
205	>	* key-value associations. They may be useful for example when
206	>	* finding the key for the greatest value. Note that "plain" Entry
207	>	* arguments can be supplied using {@code new
208	>	* AbstractMap.SimpleEntry(k,v)}.
209	>	*
210	>	* <p>Bulk operations may complete abruptly, throwing an
211	>	* exception encountered in the application of a supplied
212	>	* function. Bear in mind when handling such exceptions that other
213	>	* concurrently executing functions could also have thrown
214	>	* exceptions, or would have done so if the first exception had
215	>	* not occurred.
216	>	*
217	>	* <p>Speedups for parallel compared to sequential forms are common
218	>	* but not guaranteed.  Parallel operations involving brief functions
219	>	* on small maps may execute more slowly than sequential forms if the
220	>	* underlying work to parallelize the computation is more expensive
221	>	* than the computation itself.  Similarly, parallelization may not
222	>	* lead to much actual parallelism if all processors are busy
223	>	* performing unrelated tasks.
224	>	*
225	>	* <p>All arguments to all task methods must be non-null.
226	>	*
227	>	* <p>This class is a member of the
228	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
229	>	* Java Collections Framework</a>.
230		*
231		* @since 1.5
232		* @author Doug Lea
233	+	* @param <K> the type of keys maintained by this map
234	+	* @param <V> the type of mapped values
235		*/
236	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
237	<	implements ConcurrentMap<K, V>, Cloneable, Serializable {
236	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
237	>	implements ConcurrentMap<K,V>, Serializable {
238		private static final long serialVersionUID = 7249069246763182397L;
239
240		/*
241	<	* The basic strategy is to subdivide the table among Segments,
242	<	* each of which itself is a concurrently readable hash table.
241	>	* Overview:
242	>	*
243	>	* The primary design goal of this hash table is to maintain
244	>	* concurrent readability (typically method get(), but also
245	>	* iterators and related methods) while minimizing update
246	>	* contention. Secondary goals are to keep space consumption about
247	>	* the same or better than java.util.HashMap, and to support high
248	>	* initial insertion rates on an empty table by many threads.
249	>	*
250	>	* This map usually acts as a binned (bucketed) hash table.  Each
251	>	* key-value mapping is held in a Node.  Most nodes are instances
252	>	* of the basic Node class with hash, key, value, and next
253	>	* fields. However, various subclasses exist: TreeNodes are
254	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
255	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
256	>	* of bins during resizing. ReservationNodes are used as
257	>	* placeholders while establishing values in computeIfAbsent and
258	>	* related methods.  The types TreeBin, ForwardingNode, and
259	>	* ReservationNode do not hold normal user keys, values, or
260	>	* hashes, and are readily distinguishable during search etc
261	>	* because they have negative hash fields and null key and value
262	>	* fields. (These special nodes are either uncommon or transient,
263	>	* so the impact of carrying around some unused fields is
264	>	* insignificant.)
265	>	*
266	>	* The table is lazily initialized to a power-of-two size upon the
267	>	* first insertion.  Each bin in the table normally contains a
268	>	* list of Nodes (most often, the list has only zero or one Node).
269	>	* Table accesses require volatile/atomic reads, writes, and
270	>	* CASes.  Because there is no other way to arrange this without
271	>	* adding further indirections, we use intrinsics
272	>	* (jdk.internal.misc.Unsafe) operations.
273	>	*
274	>	* We use the top (sign) bit of Node hash fields for control
275	>	* purposes -- it is available anyway because of addressing
276	>	* constraints.  Nodes with negative hash fields are specially
277	>	* handled or ignored in map methods.
278	>	*
279	>	* Insertion (via put or its variants) of the first node in an
280	>	* empty bin is performed by just CASing it to the bin.  This is
281	>	* by far the most common case for put operations under most
282	>	* key/hash distributions.  Other update operations (insert,
283	>	* delete, and replace) require locks.  We do not want to waste
284	>	* the space required to associate a distinct lock object with
285	>	* each bin, so instead use the first node of a bin list itself as
286	>	* a lock. Locking support for these locks relies on builtin
287	>	* "synchronized" monitors.
288	>	*
289	>	* Using the first node of a list as a lock does not by itself
290	>	* suffice though: When a node is locked, any update must first
291	>	* validate that it is still the first node after locking it, and
292	>	* retry if not. Because new nodes are always appended to lists,
293	>	* once a node is first in a bin, it remains first until deleted
294	>	* or the bin becomes invalidated (upon resizing).
295	>	*
296	>	* The main disadvantage of per-bin locks is that other update
297	>	* operations on other nodes in a bin list protected by the same
298	>	* lock can stall, for example when user equals() or mapping
299	>	* functions take a long time.  However, statistically, under
300	>	* random hash codes, this is not a common problem.  Ideally, the
301	>	* frequency of nodes in bins follows a Poisson distribution
302	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
303	>	* parameter of about 0.5 on average, given the resizing threshold
304	>	* of 0.75, although with a large variance because of resizing
305	>	* granularity. Ignoring variance, the expected occurrences of
306	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
307	>	* first values are:
308	>	*
309	>	* 0:    0.60653066
310	>	* 1:    0.30326533
311	>	* 2:    0.07581633
312	>	* 3:    0.01263606
313	>	* 4:    0.00157952
314	>	* 5:    0.00015795
315	>	* 6:    0.00001316
316	>	* 7:    0.00000094
317	>	* 8:    0.00000006
318	>	* more: less than 1 in ten million
319	>	*
320	>	* Lock contention probability for two threads accessing distinct
321	>	* elements is roughly 1 / (8 * #elements) under random hashes.
322	>	*
323	>	* Actual hash code distributions encountered in practice
324	>	* sometimes deviate significantly from uniform randomness.  This
325	>	* includes the case when N > (1<<30), so some keys MUST collide.
326	>	* Similarly for dumb or hostile usages in which multiple keys are
327	>	* designed to have identical hash codes or ones that differs only
328	>	* in masked-out high bits. So we use a secondary strategy that
329	>	* applies when the number of nodes in a bin exceeds a
330	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
331	>	* specialized form of red-black trees), bounding search time to
332	>	* O(log N).  Each search step in a TreeBin is at least twice as
333	>	* slow as in a regular list, but given that N cannot exceed
334	>	* (1<<64) (before running out of addresses) this bounds search
335	>	* steps, lock hold times, etc, to reasonable constants (roughly
336	>	* 100 nodes inspected per operation worst case) so long as keys
337	>	* are Comparable (which is very common -- String, Long, etc).
338	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
339	>	* traversal pointers as regular nodes, so can be traversed in
340	>	* iterators in the same way.
341	>	*
342	>	* The table is resized when occupancy exceeds a percentage
343	>	* threshold (nominally, 0.75, but see below).  Any thread
344	>	* noticing an overfull bin may assist in resizing after the
345	>	* initiating thread allocates and sets up the replacement array.
346	>	* However, rather than stalling, these other threads may proceed
347	>	* with insertions etc.  The use of TreeBins shields us from the
348	>	* worst case effects of overfilling while resizes are in
349	>	* progress.  Resizing proceeds by transferring bins, one by one,
350	>	* from the table to the next table. However, threads claim small
351	>	* blocks of indices to transfer (via field transferIndex) before
352	>	* doing so, reducing contention.  A generation stamp in field
353	>	* sizeCtl ensures that resizings do not overlap. Because we are
354	>	* using power-of-two expansion, the elements from each bin must
355	>	* either stay at same index, or move with a power of two
356	>	* offset. We eliminate unnecessary node creation by catching
357	>	* cases where old nodes can be reused because their next fields
358	>	* won't change.  On average, only about one-sixth of them need
359	>	* cloning when a table doubles. The nodes they replace will be
360	>	* garbage collectable as soon as they are no longer referenced by
361	>	* any reader thread that may be in the midst of concurrently
362	>	* traversing table.  Upon transfer, the old table bin contains
363	>	* only a special forwarding node (with hash field "MOVED") that
364	>	* contains the next table as its key. On encountering a
365	>	* forwarding node, access and update operations restart, using
366	>	* the new table.
367	>	*
368	>	* Each bin transfer requires its bin lock, which can stall
369	>	* waiting for locks while resizing. However, because other
370	>	* threads can join in and help resize rather than contend for
371	>	* locks, average aggregate waits become shorter as resizing
372	>	* progresses.  The transfer operation must also ensure that all
373	>	* accessible bins in both the old and new table are usable by any
374	>	* traversal.  This is arranged in part by proceeding from the
375	>	* last bin (table.length - 1) up towards the first.  Upon seeing
376	>	* a forwarding node, traversals (see class Traverser) arrange to
377	>	* move to the new table without revisiting nodes.  To ensure that
378	>	* no intervening nodes are skipped even when moved out of order,
379	>	* a stack (see class TableStack) is created on first encounter of
380	>	* a forwarding node during a traversal, to maintain its place if
381	>	* later processing the current table. The need for these
382	>	* save/restore mechanics is relatively rare, but when one
383	>	* forwarding node is encountered, typically many more will be.
384	>	* So Traversers use a simple caching scheme to avoid creating so
385	>	* many new TableStack nodes. (Thanks to Peter Levart for
386	>	* suggesting use of a stack here.)
387	>	*
388	>	* The traversal scheme also applies to partial traversals of
389	>	* ranges of bins (via an alternate Traverser constructor)
390	>	* to support partitioned aggregate operations.  Also, read-only
391	>	* operations give up if ever forwarded to a null table, which
392	>	* provides support for shutdown-style clearing, which is also not
393	>	* currently implemented.
394	>	*
395	>	* Lazy table initialization minimizes footprint until first use,
396	>	* and also avoids resizings when the first operation is from a
397	>	* putAll, constructor with map argument, or deserialization.
398	>	* These cases attempt to override the initial capacity settings,
399	>	* but harmlessly fail to take effect in cases of races.
400	>	*
401	>	* The element count is maintained using a specialization of
402	>	* LongAdder. We need to incorporate a specialization rather than
403	>	* just use a LongAdder in order to access implicit
404	>	* contention-sensing that leads to creation of multiple
405	>	* CounterCells.  The counter mechanics avoid contention on
406	>	* updates but can encounter cache thrashing if read too
407	>	* frequently during concurrent access. To avoid reading so often,
408	>	* resizing under contention is attempted only upon adding to a
409	>	* bin already holding two or more nodes. Under uniform hash
410	>	* distributions, the probability of this occurring at threshold
411	>	* is around 13%, meaning that only about 1 in 8 puts check
412	>	* threshold (and after resizing, many fewer do so).
413	>	*
414	>	* TreeBins use a special form of comparison for search and
415	>	* related operations (which is the main reason we cannot use
416	>	* existing collections such as TreeMaps). TreeBins contain
417	>	* Comparable elements, but may contain others, as well as
418	>	* elements that are Comparable but not necessarily Comparable for
419	>	* the same T, so we cannot invoke compareTo among them. To handle
420	>	* this, the tree is ordered primarily by hash value, then by
421	>	* Comparable.compareTo order if applicable.  On lookup at a node,
422	>	* if elements are not comparable or compare as 0 then both left
423	>	* and right children may need to be searched in the case of tied
424	>	* hash values. (This corresponds to the full list search that
425	>	* would be necessary if all elements were non-Comparable and had
426	>	* tied hashes.) On insertion, to keep a total ordering (or as
427	>	* close as is required here) across rebalancings, we compare
428	>	* classes and identityHashCodes as tie-breakers. The red-black
429	>	* balancing code is updated from pre-jdk-collections
430	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
431	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
432	>	* Algorithms" (CLR).
433	>	*
434	>	* TreeBins also require an additional locking mechanism.  While
435	>	* list traversal is always possible by readers even during
436	>	* updates, tree traversal is not, mainly because of tree-rotations
437	>	* that may change the root node and/or its linkages.  TreeBins
438	>	* include a simple read-write lock mechanism parasitic on the
439	>	* main bin-synchronization strategy: Structural adjustments
440	>	* associated with an insertion or removal are already bin-locked
441	>	* (and so cannot conflict with other writers) but must wait for
442	>	* ongoing readers to finish. Since there can be only one such
443	>	* waiter, we use a simple scheme using a single "waiter" field to
444	>	* block writers.  However, readers need never block.  If the root
445	>	* lock is held, they proceed along the slow traversal path (via
446	>	* next-pointers) until the lock becomes available or the list is
447	>	* exhausted, whichever comes first. These cases are not fast, but
448	>	* maximize aggregate expected throughput.
449	>	*
450	>	* Maintaining API and serialization compatibility with previous
451	>	* versions of this class introduces several oddities. Mainly: We
452	>	* leave untouched but unused constructor arguments referring to
453	>	* concurrencyLevel. We accept a loadFactor constructor argument,
454	>	* but apply it only to initial table capacity (which is the only
455	>	* time that we can guarantee to honor it.) We also declare an
456	>	* unused "Segment" class that is instantiated in minimal form
457	>	* only when serializing.
458	>	*
459	>	* Also, solely for compatibility with previous versions of this
460	>	* class, it extends AbstractMap, even though all of its methods
461	>	* are overridden, so it is just useless baggage.
462	>	*
463	>	* This file is organized to make things a little easier to follow
464	>	* while reading than they might otherwise: First the main static
465	>	* declarations and utilities, then fields, then main public
466	>	* methods (with a few factorings of multiple public methods into
467	>	* internal ones), then sizing methods, trees, traversers, and
468	>	* bulk operations.
469		*/
470
471		/* ---------------- Constants -------------- */
472
473		/**
474	<	* The default initial number of table slots for this table.
475	<	* Used when not otherwise specified in constructor.
474	>	* The largest possible table capacity.  This value must be
475	>	* exactly 1<<30 to stay within Java array allocation and indexing
476	>	* bounds for power of two table sizes, and is further required
477	>	* because the top two bits of 32bit hash fields are used for
478	>	* control purposes.
479		*/
480	<	private static int DEFAULT_INITIAL_CAPACITY = 16;
480	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
481
482		/**
483	<	* The maximum capacity, used if a higher value is implicitly
484	<	* 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.
483	>	* The default initial table capacity.  Must be a power of 2
484	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
485		*/
486	<	static final int MAXIMUM_CAPACITY = 1 << 30;
486	>	private static final int DEFAULT_CAPACITY = 16;
487
488		/**
489	<	* The default load factor for this table.  Used when not
490	<	* otherwise specified in constructor.
489	>	* The largest possible (non-power of two) array size.
490	>	* Needed by toArray and related methods.
491		*/
492	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
492	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
493
494		/**
495	<	* The default number of concurrency control segments.
496	<	**/
497	<	private static final int DEFAULT_SEGMENTS = 16;
495	>	* The default concurrency level for this table. Unused but
496	>	* defined for compatibility with previous versions of this class.
497	>	*/
498	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
499
500		/**
501	<	* The maximum number of segments to allow; used to bound ctor arguments.
501	>	* The load factor for this table. Overrides of this value in
502	>	* constructors affect only the initial table capacity.  The
503	>	* actual floating point value isn't normally used -- it is
504	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
505	>	* the associated resizing threshold.
506		*/
507	<	private static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
507	>	private static final float LOAD_FACTOR = 0.75f;
508	>
509	>	/**
510	>	* The bin count threshold for using a tree rather than list for a
511	>	* bin.  Bins are converted to trees when adding an element to a
512	>	* bin with at least this many nodes. The value must be greater
513	>	* than 2, and should be at least 8 to mesh with assumptions in
514	>	* tree removal about conversion back to plain bins upon
515	>	* shrinkage.
516	>	*/
517	>	static final int TREEIFY_THRESHOLD = 8;
518	>
519	>	/**
520	>	* The bin count threshold for untreeifying a (split) bin during a
521	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
522	>	* most 6 to mesh with shrinkage detection under removal.
523	>	*/
524	>	static final int UNTREEIFY_THRESHOLD = 6;
525	>
526	>	/**
527	>	* The smallest table capacity for which bins may be treeified.
528	>	* (Otherwise the table is resized if too many nodes in a bin.)
529	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
530	>	* conflicts between resizing and treeification thresholds.
531	>	*/
532	>	static final int MIN_TREEIFY_CAPACITY = 64;
533	>
534	>	/**
535	>	* Minimum number of rebinnings per transfer step. Ranges are
536	>	* subdivided to allow multiple resizer threads.  This value
537	>	* serves as a lower bound to avoid resizers encountering
538	>	* excessive memory contention.  The value should be at least
539	>	* DEFAULT_CAPACITY.
540	>	*/
541	>	private static final int MIN_TRANSFER_STRIDE = 16;
542	>
543	>	/**
544	>	* The number of bits used for generation stamp in sizeCtl.
545	>	* Must be at least 6 for 32bit arrays.
546	>	*/
547	>	private static final int RESIZE_STAMP_BITS = 16;
548	>
549	>	/**
550	>	* The maximum number of threads that can help resize.
551	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
552	>	*/
553	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
554	>
555	>	/**
556	>	* The bit shift for recording size stamp in sizeCtl.
557	>	*/
558	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
559	>
560	>	/*
561	>	* Encodings for Node hash fields. See above for explanation.
562	>	*/
563	>	static final int MOVED     = -1; // hash for forwarding nodes
564	>	static final int TREEBIN   = -2; // hash for roots of trees
565	>	static final int RESERVED  = -3; // hash for transient reservations
566	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
567	>
568	>	/** Number of CPUS, to place bounds on some sizings */
569	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
570	>
571	>	/**
572	>	* Serialized pseudo-fields, provided only for jdk7 compatibility.
573	>	* @serialField segments Segment[]
574	>	*   The segments, each of which is a specialized hash table.
575	>	* @serialField segmentMask int
576	>	*   Mask value for indexing into segments. The upper bits of a
577	>	*   key's hash code are used to choose the segment.
578	>	* @serialField segmentShift int
579	>	*   Shift value for indexing within segments.
580	>	*/
581	>	private static final ObjectStreamField[] serialPersistentFields = {
582	>	new ObjectStreamField("segments", Segment[].class),
583	>	new ObjectStreamField("segmentMask", Integer.TYPE),
584	>	new ObjectStreamField("segmentShift", Integer.TYPE),
585	>	};
586	>
587	>	/* ---------------- Nodes -------------- */
588	>
589	>	/**
590	>	* Key-value entry.  This class is never exported out as a
591	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
592	>	* MapEntry below), but can be used for read-only traversals used
593	>	* in bulk tasks.  Subclasses of Node with a negative hash field
594	>	* are special, and contain null keys and values (but are never
595	>	* exported).  Otherwise, keys and vals are never null.
596	>	*/
597	>	static class Node<K,V> implements Map.Entry<K,V> {
598	>	final int hash;
599	>	final K key;
600	>	volatile V val;
601	>	volatile Node<K,V> next;
602	>
603	>	Node(int hash, K key, V val) {
604	>	this.hash = hash;
605	>	this.key = key;
606	>	this.val = val;
607	>	}
608	>
609	>	Node(int hash, K key, V val, Node<K,V> next) {
610	>	this(hash, key, val);
611	>	this.next = next;
612	>	}
613	>
614	>	public final K getKey()     { return key; }
615	>	public final V getValue()   { return val; }
616	>	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
617	>	public final String toString() {
618	>	return Helpers.mapEntryToString(key, val);
619	>	}
620	>	public final V setValue(V value) {
621	>	throw new UnsupportedOperationException();
622	>	}
623	>
624	>	public final boolean equals(Object o) {
625	>	Object k, v, u; Map.Entry<?,?> e;
626	>	return ((o instanceof Map.Entry) &&
627	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
628	>	(v = e.getValue()) != null &&
629	>	(k == key || k.equals(key)) &&
630	>	(v == (u = val) || v.equals(u)));
631	>	}
632	>
633	>	/**
634	>	* Virtualized support for map.get(); overridden in subclasses.
635	>	*/
636	>	Node<K,V> find(int h, Object k) {
637	>	Node<K,V> e = this;
638	>	if (k != null) {
639	>	do {
640	>	K ek;
641	>	if (e.hash == h &&
642	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
643	>	return e;
644	>	} while ((e = e.next) != null);
645	>	}
646	>	return null;
647	>	}
648	>	}
649	>
650	>	/* ---------------- Static utilities -------------- */
651	>
652	>	/**
653	>	* Spreads (XORs) higher bits of hash to lower and also forces top
654	>	* bit to 0. Because the table uses power-of-two masking, sets of
655	>	* hashes that vary only in bits above the current mask will
656	>	* always collide. (Among known examples are sets of Float keys
657	>	* holding consecutive whole numbers in small tables.)  So we
658	>	* apply a transform that spreads the impact of higher bits
659	>	* downward. There is a tradeoff between speed, utility, and
660	>	* quality of bit-spreading. Because many common sets of hashes
661	>	* are already reasonably distributed (so don't benefit from
662	>	* spreading), and because we use trees to handle large sets of
663	>	* collisions in bins, we just XOR some shifted bits in the
664	>	* cheapest possible way to reduce systematic lossage, as well as
665	>	* to incorporate impact of the highest bits that would otherwise
666	>	* never be used in index calculations because of table bounds.
667	>	*/
668	>	static final int spread(int h) {
669	>	return (h ^ (h >>> 16)) & HASH_BITS;
670	>	}
671	>
672	>	/**
673	>	* Returns a power of two table size for the given desired capacity.
674	>	* See Hackers Delight, sec 3.2
675	>	*/
676	>	private static final int tableSizeFor(int c) {
677	>	int n = c - 1;
678	>	n |= n >>> 1;
679	>	n |= n >>> 2;
680	>	n |= n >>> 4;
681	>	n |= n >>> 8;
682	>	n |= n >>> 16;
683	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
684	>	}
685	>
686	>	/**
687	>	* Returns x's Class if it is of the form "class C implements
688	>	* Comparable<C>", else null.
689	>	*/
690	>	static Class<?> comparableClassFor(Object x) {
691	>	if (x instanceof Comparable) {
692	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
693	>	if ((c = x.getClass()) == String.class) // bypass checks
694	>	return c;
695	>	if ((ts = c.getGenericInterfaces()) != null) {
696	>	for (int i = 0; i < ts.length; ++i) {
697	>	if (((t = ts[i]) instanceof ParameterizedType) &&
698	>	((p = (ParameterizedType)t).getRawType() ==
699	>	Comparable.class) &&
700	>	(as = p.getActualTypeArguments()) != null &&
701	>	as.length == 1 && as[0] == c) // type arg is c
702	>	return c;
703	>	}
704	>	}
705	>	}
706	>	return null;
707	>	}
708	>
709	>	/**
710	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
711	>	* class), else 0.
712	>	*/
713	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
714	>	static int compareComparables(Class<?> kc, Object k, Object x) {
715	>	return (x == null || x.getClass() != kc ? 0 :
716	>	((Comparable)k).compareTo(x));
717	>	}
718	>
719	>	/* ---------------- Table element access -------------- */
720	>
721	>	/*
722	>	* Atomic access methods are used for table elements as well as
723	>	* elements of in-progress next table while resizing.  All uses of
724	>	* the tab arguments must be null checked by callers.  All callers
725	>	* also paranoically precheck that tab's length is not zero (or an
726	>	* equivalent check), thus ensuring that any index argument taking
727	>	* the form of a hash value anded with (length - 1) is a valid
728	>	* index.  Note that, to be correct wrt arbitrary concurrency
729	>	* errors by users, these checks must operate on local variables,
730	>	* which accounts for some odd-looking inline assignments below.
731	>	* Note that calls to setTabAt always occur within locked regions,
732	>	* and so require only release ordering.
733	>	*/
734	>
735	>	@SuppressWarnings("unchecked")
736	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
737	>	return (Node<K,V>)U.getObjectAcquire(tab, ((long)i << ASHIFT) + ABASE);
738	>	}
739	>
740	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
741	>	Node<K,V> c, Node<K,V> v) {
742	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
743	>	}
744	>
745	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
746	>	U.putObjectRelease(tab, ((long)i << ASHIFT) + ABASE, v);
747	>	}
748
749		/* ---------------- Fields -------------- */
750
751		/**
752	<	* Mask value for indexing into segments. The upper bits of a
753	<	* key's hash code are used to choose the segment.
754	<	**/
755	<	private final int segmentMask;
752	>	* The array of bins. Lazily initialized upon first insertion.
753	>	* Size is always a power of two. Accessed directly by iterators.
754	>	*/
755	>	transient volatile Node<K,V>[] table;
756	>
757	>	/**
758	>	* The next table to use; non-null only while resizing.
759	>	*/
760	>	private transient volatile Node<K,V>[] nextTable;
761	>
762	>	/**
763	>	* Base counter value, used mainly when there is no contention,
764	>	* but also as a fallback during table initialization
765	>	* races. Updated via CAS.
766	>	*/
767	>	private transient volatile long baseCount;
768	>
769	>	/**
770	>	* Table initialization and resizing control.  When negative, the
771	>	* table is being initialized or resized: -1 for initialization,
772	>	* else -(1 + the number of active resizing threads).  Otherwise,
773	>	* when table is null, holds the initial table size to use upon
774	>	* creation, or 0 for default. After initialization, holds the
775	>	* next element count value upon which to resize the table.
776	>	*/
777	>	private transient volatile int sizeCtl;
778	>
779	>	/**
780	>	* The next table index (plus one) to split while resizing.
781	>	*/
782	>	private transient volatile int transferIndex;
783
784		/**
785	<	* Shift value for indexing within segments.
786	<	**/
787	<	private final int segmentShift;
785	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
786	>	*/
787	>	private transient volatile int cellsBusy;
788
789		/**
790	<	* The segments, each of which is a specialized hash table
790	>	* Table of counter cells. When non-null, size is a power of 2.
791		*/
792	<	private final Segment[] segments;
792	>	private transient volatile CounterCell[] counterCells;
793
794	<	private transient Set<K> keySet;
795	<	private transient Set<Map.Entry<K,V>> entrySet;
796	<	private transient Collection<V> values;
794	>	// views
795	>	private transient KeySetView<K,V> keySet;
796	>	private transient ValuesView<K,V> values;
797	>	private transient EntrySetView<K,V> entrySet;
798
799	<	/* ---------------- Small Utilities -------------- */
799	>
800	>	/* ---------------- Public operations -------------- */
801	>
802	>	/**
803	>	* Creates a new, empty map with the default initial table size (16).
804	>	*/
805	>	public ConcurrentHashMap() {
806	>	}
807
808		/**
809	<	* Return a hash code for non-null Object x.
810	<	* Uses the same hash code spreader as most other j.u hash tables.
811	<	* @param x the object serving as a key
812	<	* @return the hash code
809	>	* Creates a new, empty map with an initial table size
810	>	* accommodating the specified number of elements without the need
811	>	* to dynamically resize.
812	>	*
813	>	* @param initialCapacity The implementation performs internal
814	>	* sizing to accommodate this many elements.
815	>	* @throws IllegalArgumentException if the initial capacity of
816	>	* elements is negative
817		*/
818	<	private static int hash(Object x) {
819	<	int h = x.hashCode();
820	<	h += ~(h << 9);
821	<	h ^=  (h >>> 14);
822	<	h +=  (h << 4);
823	<	h ^=  (h >>> 10);
818	>	public ConcurrentHashMap(int initialCapacity) {
819	>	if (initialCapacity < 0)
820	>	throw new IllegalArgumentException();
821	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
822	>	MAXIMUM_CAPACITY :
823	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
824	>	this.sizeCtl = cap;
825	>	}
826	>
827	>	/**
828	>	* Creates a new map with the same mappings as the given map.
829	>	*
830	>	* @param m the map
831	>	*/
832	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
833	>	this.sizeCtl = DEFAULT_CAPACITY;
834	>	putAll(m);
835	>	}
836	>
837	>	/**
838	>	* Creates a new, empty map with an initial table size based on
839	>	* the given number of elements ({@code initialCapacity}) and
840	>	* initial table density ({@code loadFactor}).
841	>	*
842	>	* @param initialCapacity the initial capacity. The implementation
843	>	* performs internal sizing to accommodate this many elements,
844	>	* given the specified load factor.
845	>	* @param loadFactor the load factor (table density) for
846	>	* establishing the initial table size
847	>	* @throws IllegalArgumentException if the initial capacity of
848	>	* elements is negative or the load factor is nonpositive
849	>	*
850	>	* @since 1.6
851	>	*/
852	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
853	>	this(initialCapacity, loadFactor, 1);
854	>	}
855	>
856	>	/**
857	>	* Creates a new, empty map with an initial table size based on
858	>	* the given number of elements ({@code initialCapacity}), table
859	>	* density ({@code loadFactor}), and number of concurrently
860	>	* updating threads ({@code concurrencyLevel}).
861	>	*
862	>	* @param initialCapacity the initial capacity. The implementation
863	>	* performs internal sizing to accommodate this many elements,
864	>	* given the specified load factor.
865	>	* @param loadFactor the load factor (table density) for
866	>	* establishing the initial table size
867	>	* @param concurrencyLevel the estimated number of concurrently
868	>	* updating threads. The implementation may use this value as
869	>	* a sizing hint.
870	>	* @throws IllegalArgumentException if the initial capacity is
871	>	* negative or the load factor or concurrencyLevel are
872	>	* nonpositive
873	>	*/
874	>	public ConcurrentHashMap(int initialCapacity,
875	>	float loadFactor, int concurrencyLevel) {
876	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
877	>	throw new IllegalArgumentException();
878	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
879	>	initialCapacity = concurrencyLevel;   // as estimated threads
880	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
881	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
882	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
883	>	this.sizeCtl = cap;
884	>	}
885	>
886	>	// Original (since JDK1.2) Map methods
887	>
888	>	/**
889	>	* {@inheritDoc}
890	>	*/
891	>	public int size() {
892	>	long n = sumCount();
893	>	return ((n < 0L) ? 0 :
894	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
895	>	(int)n);
896	>	}
897	>
898	>	/**
899	>	* {@inheritDoc}
900	>	*/
901	>	public boolean isEmpty() {
902	>	return sumCount() <= 0L; // ignore transient negative values
903	>	}
904	>
905	>	/**
906	>	* Returns the value to which the specified key is mapped,
907	>	* or {@code null} if this map contains no mapping for the key.
908	>	*
909	>	* <p>More formally, if this map contains a mapping from a key
910	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
911	>	* then this method returns {@code v}; otherwise it returns
912	>	* {@code null}.  (There can be at most one such mapping.)
913	>	*
914	>	* @throws NullPointerException if the specified key is null
915	>	*/
916	>	public V get(Object key) {
917	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
918	>	int h = spread(key.hashCode());
919	>	if ((tab = table) != null && (n = tab.length) > 0 &&
920	>	(e = tabAt(tab, (n - 1) & h)) != null) {
921	>	if ((eh = e.hash) == h) {
922	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
923	>	return e.val;
924	>	}
925	>	else if (eh < 0)
926	>	return (p = e.find(h, key)) != null ? p.val : null;
927	>	while ((e = e.next) != null) {
928	>	if (e.hash == h &&
929	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
930	>	return e.val;
931	>	}
932	>	}
933	>	return null;
934	>	}
935	>
936	>	/**
937	>	* Tests if the specified object is a key in this table.
938	>	*
939	>	* @param  key possible key
940	>	* @return {@code true} if and only if the specified object
941	>	*         is a key in this table, as determined by the
942	>	*         {@code equals} method; {@code false} otherwise
943	>	* @throws NullPointerException if the specified key is null
944	>	*/
945	>	public boolean containsKey(Object key) {
946	>	return get(key) != null;
947	>	}
948	>
949	>	/**
950	>	* Returns {@code true} if this map maps one or more keys to the
951	>	* specified value. Note: This method may require a full traversal
952	>	* of the map, and is much slower than method {@code containsKey}.
953	>	*
954	>	* @param value value whose presence in this map is to be tested
955	>	* @return {@code true} if this map maps one or more keys to the
956	>	*         specified value
957	>	* @throws NullPointerException if the specified value is null
958	>	*/
959	>	public boolean containsValue(Object value) {
960	>	if (value == null)
961	>	throw new NullPointerException();
962	>	Node<K,V>[] t;
963	>	if ((t = table) != null) {
964	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
965	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
966	>	V v;
967	>	if ((v = p.val) == value || (v != null && value.equals(v)))
968	>	return true;
969	>	}
970	>	}
971	>	return false;
972	>	}
973	>
974	>	/**
975	>	* Maps the specified key to the specified value in this table.
976	>	* Neither the key nor the value can be null.
977	>	*
978	>	* <p>The value can be retrieved by calling the {@code get} method
979	>	* with a key that is equal to the original key.
980	>	*
981	>	* @param key key with which the specified value is to be associated
982	>	* @param value value to be associated with the specified key
983	>	* @return the previous value associated with {@code key}, or
984	>	*         {@code null} if there was no mapping for {@code key}
985	>	* @throws NullPointerException if the specified key or value is null
986	>	*/
987	>	public V put(K key, V value) {
988	>	return putVal(key, value, false);
989	>	}
990	>
991	>	/** Implementation for put and putIfAbsent */
992	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
993	>	if (key == null || value == null) throw new NullPointerException();
994	>	int hash = spread(key.hashCode());
995	>	int binCount = 0;
996	>	for (Node<K,V>[] tab = table;;) {
997	>	Node<K,V> f; int n, i, fh; K fk; V fv;
998	>	if (tab == null || (n = tab.length) == 0)
999	>	tab = initTable();
1000	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
1001	>	if (casTabAt(tab, i, null, new Node<K,V>(hash, key, value)))
1002	>	break;                   // no lock when adding to empty bin
1003	>	}
1004	>	else if ((fh = f.hash) == MOVED)
1005	>	tab = helpTransfer(tab, f);
1006	>	else if (onlyIfAbsent && fh == hash &&  // check first node
1007	>	((fk = f.key) == key || fk != null && key.equals(fk)) &&
1008	>	(fv = f.val) != null)
1009	>	return fv;
1010	>	else {
1011	>	V oldVal = null;
1012	>	synchronized (f) {
1013	>	if (tabAt(tab, i) == f) {
1014	>	if (fh >= 0) {
1015	>	binCount = 1;
1016	>	for (Node<K,V> e = f;; ++binCount) {
1017	>	K ek;
1018	>	if (e.hash == hash &&
1019	>	((ek = e.key) == key ||
1020	>	(ek != null && key.equals(ek)))) {
1021	>	oldVal = e.val;
1022	>	if (!onlyIfAbsent)
1023	>	e.val = value;
1024	>	break;
1025	>	}
1026	>	Node<K,V> pred = e;
1027	>	if ((e = e.next) == null) {
1028	>	pred.next = new Node<K,V>(hash, key, value);
1029	>	break;
1030	>	}
1031	>	}
1032	>	}
1033	>	else if (f instanceof TreeBin) {
1034	>	Node<K,V> p;
1035	>	binCount = 2;
1036	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1037	>	value)) != null) {
1038	>	oldVal = p.val;
1039	>	if (!onlyIfAbsent)
1040	>	p.val = value;
1041	>	}
1042	>	}
1043	>	else if (f instanceof ReservationNode)
1044	>	throw new IllegalStateException("Recursive update");
1045	>	}
1046	>	}
1047	>	if (binCount != 0) {
1048	>	if (binCount >= TREEIFY_THRESHOLD)
1049	>	treeifyBin(tab, i);
1050	>	if (oldVal != null)
1051	>	return oldVal;
1052	>	break;
1053	>	}
1054	>	}
1055	>	}
1056	>	addCount(1L, binCount);
1057	>	return null;
1058	>	}
1059	>
1060	>	/**
1061	>	* Copies all of the mappings from the specified map to this one.
1062	>	* These mappings replace any mappings that this map had for any of the
1063	>	* keys currently in the specified map.
1064	>	*
1065	>	* @param m mappings to be stored in this map
1066	>	*/
1067	>	public void putAll(Map<? extends K, ? extends V> m) {
1068	>	tryPresize(m.size());
1069	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1070	>	putVal(e.getKey(), e.getValue(), false);
1071	>	}
1072	>
1073	>	/**
1074	>	* Removes the key (and its corresponding value) from this map.
1075	>	* This method does nothing if the key is not in the map.
1076	>	*
1077	>	* @param  key the key that needs to be removed
1078	>	* @return the previous value associated with {@code key}, or
1079	>	*         {@code null} if there was no mapping for {@code key}
1080	>	* @throws NullPointerException if the specified key is null
1081	>	*/
1082	>	public V remove(Object key) {
1083	>	return replaceNode(key, null, null);
1084	>	}
1085	>
1086	>	/**
1087	>	* Implementation for the four public remove/replace methods:
1088	>	* Replaces node value with v, conditional upon match of cv if
1089	>	* non-null.  If resulting value is null, delete.
1090	>	*/
1091	>	final V replaceNode(Object key, V value, Object cv) {
1092	>	int hash = spread(key.hashCode());
1093	>	for (Node<K,V>[] tab = table;;) {
1094	>	Node<K,V> f; int n, i, fh;
1095	>	if (tab == null || (n = tab.length) == 0 ||
1096	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1097	>	break;
1098	>	else if ((fh = f.hash) == MOVED)
1099	>	tab = helpTransfer(tab, f);
1100	>	else {
1101	>	V oldVal = null;
1102	>	boolean validated = false;
1103	>	synchronized (f) {
1104	>	if (tabAt(tab, i) == f) {
1105	>	if (fh >= 0) {
1106	>	validated = true;
1107	>	for (Node<K,V> e = f, pred = null;;) {
1108	>	K ek;
1109	>	if (e.hash == hash &&
1110	>	((ek = e.key) == key ||
1111	>	(ek != null && key.equals(ek)))) {
1112	>	V ev = e.val;
1113	>	if (cv == null || cv == ev ||
1114	>	(ev != null && cv.equals(ev))) {
1115	>	oldVal = ev;
1116	>	if (value != null)
1117	>	e.val = value;
1118	>	else if (pred != null)
1119	>	pred.next = e.next;
1120	>	else
1121	>	setTabAt(tab, i, e.next);
1122	>	}
1123	>	break;
1124	>	}
1125	>	pred = e;
1126	>	if ((e = e.next) == null)
1127	>	break;
1128	>	}
1129	>	}
1130	>	else if (f instanceof TreeBin) {
1131	>	validated = true;
1132	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1133	>	TreeNode<K,V> r, p;
1134	>	if ((r = t.root) != null &&
1135	>	(p = r.findTreeNode(hash, key, null)) != null) {
1136	>	V pv = p.val;
1137	>	if (cv == null || cv == pv ||
1138	>	(pv != null && cv.equals(pv))) {
1139	>	oldVal = pv;
1140	>	if (value != null)
1141	>	p.val = value;
1142	>	else if (t.removeTreeNode(p))
1143	>	setTabAt(tab, i, untreeify(t.first));
1144	>	}
1145	>	}
1146	>	}
1147	>	else if (f instanceof ReservationNode)
1148	>	throw new IllegalStateException("Recursive update");
1149	>	}
1150	>	}
1151	>	if (validated) {
1152	>	if (oldVal != null) {
1153	>	if (value == null)
1154	>	addCount(-1L, -1);
1155	>	return oldVal;
1156	>	}
1157	>	break;
1158	>	}
1159	>	}
1160	>	}
1161	>	return null;
1162	>	}
1163	>
1164	>	/**
1165	>	* Removes all of the mappings from this map.
1166	>	*/
1167	>	public void clear() {
1168	>	long delta = 0L; // negative number of deletions
1169	>	int i = 0;
1170	>	Node<K,V>[] tab = table;
1171	>	while (tab != null && i < tab.length) {
1172	>	int fh;
1173	>	Node<K,V> f = tabAt(tab, i);
1174	>	if (f == null)
1175	>	++i;
1176	>	else if ((fh = f.hash) == MOVED) {
1177	>	tab = helpTransfer(tab, f);
1178	>	i = 0; // restart
1179	>	}
1180	>	else {
1181	>	synchronized (f) {
1182	>	if (tabAt(tab, i) == f) {
1183	>	Node<K,V> p = (fh >= 0 ? f :
1184	>	(f instanceof TreeBin) ?
1185	>	((TreeBin<K,V>)f).first : null);
1186	>	while (p != null) {
1187	>	--delta;
1188	>	p = p.next;
1189	>	}
1190	>	setTabAt(tab, i++, null);
1191	>	}
1192	>	}
1193	>	}
1194	>	}
1195	>	if (delta != 0L)
1196	>	addCount(delta, -1);
1197	>	}
1198	>
1199	>	/**
1200	>	* Returns a {@link Set} view of the keys contained in this map.
1201	>	* The set is backed by the map, so changes to the map are
1202	>	* reflected in the set, and vice-versa. The set supports element
1203	>	* removal, which removes the corresponding mapping from this map,
1204	>	* via the {@code Iterator.remove}, {@code Set.remove},
1205	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1206	>	* operations.  It does not support the {@code add} or
1207	>	* {@code addAll} operations.
1208	>	*
1209	>	* <p>The view's iterators and spliterators are
1210	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1211	>	*
1212	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1213	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1214	>	*
1215	>	* @return the set view
1216	>	*/
1217	>	public KeySetView<K,V> keySet() {
1218	>	KeySetView<K,V> ks;
1219	>	if ((ks = keySet) != null) return ks;
1220	>	return keySet = new KeySetView<K,V>(this, null);
1221	>	}
1222	>
1223	>	/**
1224	>	* Returns a {@link Collection} view of the values contained in this map.
1225	>	* The collection is backed by the map, so changes to the map are
1226	>	* reflected in the collection, and vice-versa.  The collection
1227	>	* supports element removal, which removes the corresponding
1228	>	* mapping from this map, via the {@code Iterator.remove},
1229	>	* {@code Collection.remove}, {@code removeAll},
1230	>	* {@code retainAll}, and {@code clear} operations.  It does not
1231	>	* support the {@code add} or {@code addAll} operations.
1232	>	*
1233	>	* <p>The view's iterators and spliterators are
1234	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1235	>	*
1236	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1237	>	* and {@link Spliterator#NONNULL}.
1238	>	*
1239	>	* @return the collection view
1240	>	*/
1241	>	public Collection<V> values() {
1242	>	ValuesView<K,V> vs;
1243	>	if ((vs = values) != null) return vs;
1244	>	return values = new ValuesView<K,V>(this);
1245	>	}
1246	>
1247	>	/**
1248	>	* Returns a {@link Set} view of the mappings contained in this map.
1249	>	* The set is backed by the map, so changes to the map are
1250	>	* reflected in the set, and vice-versa.  The set supports element
1251	>	* removal, which removes the corresponding mapping from the map,
1252	>	* via the {@code Iterator.remove}, {@code Set.remove},
1253	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1254	>	* operations.
1255	>	*
1256	>	* <p>The view's iterators and spliterators are
1257	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1258	>	*
1259	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1260	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1261	>	*
1262	>	* @return the set view
1263	>	*/
1264	>	public Set<Map.Entry<K,V>> entrySet() {
1265	>	EntrySetView<K,V> es;
1266	>	if ((es = entrySet) != null) return es;
1267	>	return entrySet = new EntrySetView<K,V>(this);
1268	>	}
1269	>
1270	>	/**
1271	>	* Returns the hash code value for this {@link Map}, i.e.,
1272	>	* the sum of, for each key-value pair in the map,
1273	>	* {@code key.hashCode() ^ value.hashCode()}.
1274	>	*
1275	>	* @return the hash code value for this map
1276	>	*/
1277	>	public int hashCode() {
1278	>	int h = 0;
1279	>	Node<K,V>[] t;
1280	>	if ((t = table) != null) {
1281	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1282	>	for (Node<K,V> p; (p = it.advance()) != null; )
1283	>	h += p.key.hashCode() ^ p.val.hashCode();
1284	>	}
1285		return h;
1286		}
1287
1288		/**
1289	<	* Return the segment that should be used for key with given hash
1289	>	* Returns a string representation of this map.  The string
1290	>	* representation consists of a list of key-value mappings (in no
1291	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1292	>	* mappings are separated by the characters {@code ", "} (comma
1293	>	* and space).  Each key-value mapping is rendered as the key
1294	>	* followed by an equals sign ("{@code =}") followed by the
1295	>	* associated value.
1296	>	*
1297	>	* @return a string representation of this map
1298	>	*/
1299	>	public String toString() {
1300	>	Node<K,V>[] t;
1301	>	int f = (t = table) == null ? 0 : t.length;
1302	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1303	>	StringBuilder sb = new StringBuilder();
1304	>	sb.append('{');
1305	>	Node<K,V> p;
1306	>	if ((p = it.advance()) != null) {
1307	>	for (;;) {
1308	>	K k = p.key;
1309	>	V v = p.val;
1310	>	sb.append(k == this ? "(this Map)" : k);
1311	>	sb.append('=');
1312	>	sb.append(v == this ? "(this Map)" : v);
1313	>	if ((p = it.advance()) == null)
1314	>	break;
1315	>	sb.append(',').append(' ');
1316	>	}
1317	>	}
1318	>	return sb.append('}').toString();
1319	>	}
1320	>
1321	>	/**
1322	>	* Compares the specified object with this map for equality.
1323	>	* Returns {@code true} if the given object is a map with the same
1324	>	* mappings as this map.  This operation may return misleading
1325	>	* results if either map is concurrently modified during execution
1326	>	* of this method.
1327	>	*
1328	>	* @param o object to be compared for equality with this map
1329	>	* @return {@code true} if the specified object is equal to this map
1330		*/
1331	<	private Segment<K,V> segmentFor(int hash) {
1332	<	return (Segment<K,V>) segments[(hash >>> segmentShift) & segmentMask];
1331	>	public boolean equals(Object o) {
1332	>	if (o != this) {
1333	>	if (!(o instanceof Map))
1334	>	return false;
1335	>	Map<?,?> m = (Map<?,?>) o;
1336	>	Node<K,V>[] t;
1337	>	int f = (t = table) == null ? 0 : t.length;
1338	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1339	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1340	>	V val = p.val;
1341	>	Object v = m.get(p.key);
1342	>	if (v == null || (v != val && !v.equals(val)))
1343	>	return false;
1344	>	}
1345	>	for (Map.Entry<?,?> e : m.entrySet()) {
1346	>	Object mk, mv, v;
1347	>	if ((mk = e.getKey()) == null ||
1348	>	(mv = e.getValue()) == null ||
1349	>	(v = get(mk)) == null ||
1350	>	(mv != v && !mv.equals(v)))
1351	>	return false;
1352	>	}
1353	>	}
1354	>	return true;
1355		}
1356
1357	<	/* ---------------- Inner Classes -------------- */
1357	>	/**
1358	>	* Stripped-down version of helper class used in previous version,
1359	>	* declared for the sake of serialization compatibility.
1360	>	*/
1361	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1362	>	private static final long serialVersionUID = 2249069246763182397L;
1363	>	final float loadFactor;
1364	>	Segment(float lf) { this.loadFactor = lf; }
1365	>	}
1366
1367		/**
1368	<	* Segments are specialized versions of hash tables.  This
1369	<	* subclasses from ReentrantLock opportunistically, just to
1370	<	* simplify some locking and avoid separate construction.
1371	<	**/
1372	<	private static final class Segment<K,V> extends ReentrantLock implements Serializable {
1368	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1369	>	* stream (i.e., serializes it).
1370	>	* @param s the stream
1371	>	* @throws java.io.IOException if an I/O error occurs
1372	>	* @serialData
1373	>	* the serialized fields, followed by the key (Object) and value
1374	>	* (Object) for each key-value mapping, followed by a null pair.
1375	>	* The key-value mappings are emitted in no particular order.
1376	>	*/
1377	>	private void writeObject(java.io.ObjectOutputStream s)
1378	>	throws java.io.IOException {
1379	>	// For serialization compatibility
1380	>	// Emulate segment calculation from previous version of this class
1381	>	int sshift = 0;
1382	>	int ssize = 1;
1383	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1384	>	++sshift;
1385	>	ssize <<= 1;
1386	>	}
1387	>	int segmentShift = 32 - sshift;
1388	>	int segmentMask = ssize - 1;
1389	>	@SuppressWarnings("unchecked")
1390	>	Segment<K,V>[] segments = (Segment<K,V>[])
1391	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1392	>	for (int i = 0; i < segments.length; ++i)
1393	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1394	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1395	>	streamFields.put("segments", segments);
1396	>	streamFields.put("segmentShift", segmentShift);
1397	>	streamFields.put("segmentMask", segmentMask);
1398	>	s.writeFields();
1399	>
1400	>	Node<K,V>[] t;
1401	>	if ((t = table) != null) {
1402	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1403	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1404	>	s.writeObject(p.key);
1405	>	s.writeObject(p.val);
1406	>	}
1407	>	}
1408	>	s.writeObject(null);
1409	>	s.writeObject(null);
1410	>	}
1411	>
1412	>	/**
1413	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1414	>	* @param s the stream
1415	>	* @throws ClassNotFoundException if the class of a serialized object
1416	>	*         could not be found
1417	>	* @throws java.io.IOException if an I/O error occurs
1418	>	*/
1419	>	private void readObject(java.io.ObjectInputStream s)
1420	>	throws java.io.IOException, ClassNotFoundException {
1421		/*
1422	<	* Segments maintain a table of entry lists that are ALWAYS
1423	<	* kept in a consistent state, so can be read without locking.
1424	<	* Next fields of nodes are immutable (final).  All list
1425	<	* additions are performed at the front of each bin. This
1426	<	* makes it easy to check changes, and also fast to traverse.
164	<	* When nodes would otherwise be changed, new nodes are
165	<	* created to replace them. This works well for hash tables
166	<	* 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.
1422	>	* To improve performance in typical cases, we create nodes
1423	>	* while reading, then place in table once size is known.
1424	>	* However, we must also validate uniqueness and deal with
1425	>	* overpopulated bins while doing so, which requires
1426	>	* specialized versions of putVal mechanics.
1427		*/
1428	+	sizeCtl = -1; // force exclusion for table construction
1429	+	s.defaultReadObject();
1430	+	long size = 0L;
1431	+	Node<K,V> p = null;
1432	+	for (;;) {
1433	+	@SuppressWarnings("unchecked")
1434	+	K k = (K) s.readObject();
1435	+	@SuppressWarnings("unchecked")
1436	+	V v = (V) s.readObject();
1437	+	if (k != null && v != null) {
1438	+	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1439	+	++size;
1440	+	}
1441	+	else
1442	+	break;
1443	+	}
1444	+	if (size == 0L)
1445	+	sizeCtl = 0;
1446	+	else {
1447	+	int n;
1448	+	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1449	+	n = MAXIMUM_CAPACITY;
1450	+	else {
1451	+	int sz = (int)size;
1452	+	n = tableSizeFor(sz + (sz >>> 1) + 1);
1453	+	}
1454	+	@SuppressWarnings("unchecked")
1455	+	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1456	+	int mask = n - 1;
1457	+	long added = 0L;
1458	+	while (p != null) {
1459	+	boolean insertAtFront;
1460	+	Node<K,V> next = p.next, first;
1461	+	int h = p.hash, j = h & mask;
1462	+	if ((first = tabAt(tab, j)) == null)
1463	+	insertAtFront = true;
1464	+	else {
1465	+	K k = p.key;
1466	+	if (first.hash < 0) {
1467	+	TreeBin<K,V> t = (TreeBin<K,V>)first;
1468	+	if (t.putTreeVal(h, k, p.val) == null)
1469	+	++added;
1470	+	insertAtFront = false;
1471	+	}
1472	+	else {
1473	+	int binCount = 0;
1474	+	insertAtFront = true;
1475	+	Node<K,V> q; K qk;
1476	+	for (q = first; q != null; q = q.next) {
1477	+	if (q.hash == h &&
1478	+	((qk = q.key) == k ||
1479	+	(qk != null && k.equals(qk)))) {
1480	+	insertAtFront = false;
1481	+	break;
1482	+	}
1483	+	++binCount;
1484	+	}
1485	+	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1486	+	insertAtFront = false;
1487	+	++added;
1488	+	p.next = first;
1489	+	TreeNode<K,V> hd = null, tl = null;
1490	+	for (q = p; q != null; q = q.next) {
1491	+	TreeNode<K,V> t = new TreeNode<K,V>
1492	+	(q.hash, q.key, q.val, null, null);
1493	+	if ((t.prev = tl) == null)
1494	+	hd = t;
1495	+	else
1496	+	tl.next = t;
1497	+	tl = t;
1498	+	}
1499	+	setTabAt(tab, j, new TreeBin<K,V>(hd));
1500	+	}
1501	+	}
1502	+	}
1503	+	if (insertAtFront) {
1504	+	++added;
1505	+	p.next = first;
1506	+	setTabAt(tab, j, p);
1507	+	}
1508	+	p = next;
1509	+	}
1510	+	table = tab;
1511	+	sizeCtl = n - (n >>> 2);
1512	+	baseCount = added;
1513	+	}
1514	+	}
1515
1516	<	private static final long serialVersionUID = 2249069246763182397L;
1516	>	// ConcurrentMap methods
1517
1518	<	/**
1519	<	* The number of elements in this segment's region.
1520	<	**/
1521	<	transient volatile int count;
1518	>	/**
1519	>	* {@inheritDoc}
1520	>	*
1521	>	* @return the previous value associated with the specified key,
1522	>	*         or {@code null} if there was no mapping for the key
1523	>	* @throws NullPointerException if the specified key or value is null
1524	>	*/
1525	>	public V putIfAbsent(K key, V value) {
1526	>	return putVal(key, value, true);
1527	>	}
1528	>
1529	>	/**
1530	>	* {@inheritDoc}
1531	>	*
1532	>	* @throws NullPointerException if the specified key is null
1533	>	*/
1534	>	public boolean remove(Object key, Object value) {
1535	>	if (key == null)
1536	>	throw new NullPointerException();
1537	>	return value != null && replaceNode(key, null, value) != null;
1538	>	}
1539	>
1540	>	/**
1541	>	* {@inheritDoc}
1542	>	*
1543	>	* @throws NullPointerException if any of the arguments are null
1544	>	*/
1545	>	public boolean replace(K key, V oldValue, V newValue) {
1546	>	if (key == null || oldValue == null || newValue == null)
1547	>	throw new NullPointerException();
1548	>	return replaceNode(key, newValue, oldValue) != null;
1549	>	}
1550	>
1551	>	/**
1552	>	* {@inheritDoc}
1553	>	*
1554	>	* @return the previous value associated with the specified key,
1555	>	*         or {@code null} if there was no mapping for the key
1556	>	* @throws NullPointerException if the specified key or value is null
1557	>	*/
1558	>	public V replace(K key, V value) {
1559	>	if (key == null || value == null)
1560	>	throw new NullPointerException();
1561	>	return replaceNode(key, value, null);
1562	>	}
1563	>
1564	>	// Overrides of JDK8+ Map extension method defaults
1565	>
1566	>	/**
1567	>	* Returns the value to which the specified key is mapped, or the
1568	>	* given default value if this map contains no mapping for the
1569	>	* key.
1570	>	*
1571	>	* @param key the key whose associated value is to be returned
1572	>	* @param defaultValue the value to return if this map contains
1573	>	* no mapping for the given key
1574	>	* @return the mapping for the key, if present; else the default value
1575	>	* @throws NullPointerException if the specified key is null
1576	>	*/
1577	>	public V getOrDefault(Object key, V defaultValue) {
1578	>	V v;
1579	>	return (v = get(key)) == null ? defaultValue : v;
1580	>	}
1581	>
1582	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1583	>	if (action == null) throw new NullPointerException();
1584	>	Node<K,V>[] t;
1585	>	if ((t = table) != null) {
1586	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1587	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1588	>	action.accept(p.key, p.val);
1589	>	}
1590	>	}
1591	>	}
1592	>
1593	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1594	>	if (function == null) throw new NullPointerException();
1595	>	Node<K,V>[] t;
1596	>	if ((t = table) != null) {
1597	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1598	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1599	>	V oldValue = p.val;
1600	>	for (K key = p.key;;) {
1601	>	V newValue = function.apply(key, oldValue);
1602	>	if (newValue == null)
1603	>	throw new NullPointerException();
1604	>	if (replaceNode(key, newValue, oldValue) != null ||
1605	>	(oldValue = get(key)) == null)
1606	>	break;
1607	>	}
1608	>	}
1609	>	}
1610	>	}
1611	>
1612	>	/**
1613	>	* Helper method for EntrySetView.removeIf.
1614	>	*/
1615	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1616	>	if (function == null) throw new NullPointerException();
1617	>	Node<K,V>[] t;
1618	>	boolean removed = false;
1619	>	if ((t = table) != null) {
1620	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1621	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1622	>	K k = p.key;
1623	>	V v = p.val;
1624	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1625	>	if (function.test(e) && replaceNode(k, null, v) != null)
1626	>	removed = true;
1627	>	}
1628	>	}
1629	>	return removed;
1630	>	}
1631	>
1632	>	/**
1633	>	* Helper method for ValuesView.removeIf.
1634	>	*/
1635	>	boolean removeValueIf(Predicate<? super V> function) {
1636	>	if (function == null) throw new NullPointerException();
1637	>	Node<K,V>[] t;
1638	>	boolean removed = false;
1639	>	if ((t = table) != null) {
1640	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1641	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1642	>	K k = p.key;
1643	>	V v = p.val;
1644	>	if (function.test(v) && replaceNode(k, null, v) != null)
1645	>	removed = true;
1646	>	}
1647	>	}
1648	>	return removed;
1649	>	}
1650	>
1651	>	/**
1652	>	* If the specified key is not already associated with a value,
1653	>	* attempts to compute its value using the given mapping function
1654	>	* and enters it into this map unless {@code null}.  The entire
1655	>	* method invocation is performed atomically, so the function is
1656	>	* applied at most once per key.  Some attempted update operations
1657	>	* on this map by other threads may be blocked while computation
1658	>	* is in progress, so the computation should be short and simple,
1659	>	* and must not attempt to update any other mappings of this map.
1660	>	*
1661	>	* @param key key with which the specified value is to be associated
1662	>	* @param mappingFunction the function to compute a value
1663	>	* @return the current (existing or computed) value associated with
1664	>	*         the specified key, or null if the computed value is null
1665	>	* @throws NullPointerException if the specified key or mappingFunction
1666	>	*         is null
1667	>	* @throws IllegalStateException if the computation detectably
1668	>	*         attempts a recursive update to this map that would
1669	>	*         otherwise never complete
1670	>	* @throws RuntimeException or Error if the mappingFunction does so,
1671	>	*         in which case the mapping is left unestablished
1672	>	*/
1673	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1674	>	if (key == null || mappingFunction == null)
1675	>	throw new NullPointerException();
1676	>	int h = spread(key.hashCode());
1677	>	V val = null;
1678	>	int binCount = 0;
1679	>	for (Node<K,V>[] tab = table;;) {
1680	>	Node<K,V> f; int n, i, fh; K fk; V fv;
1681	>	if (tab == null || (n = tab.length) == 0)
1682	>	tab = initTable();
1683	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1684	>	Node<K,V> r = new ReservationNode<K,V>();
1685	>	synchronized (r) {
1686	>	if (casTabAt(tab, i, null, r)) {
1687	>	binCount = 1;
1688	>	Node<K,V> node = null;
1689	>	try {
1690	>	if ((val = mappingFunction.apply(key)) != null)
1691	>	node = new Node<K,V>(h, key, val);
1692	>	} finally {
1693	>	setTabAt(tab, i, node);
1694	>	}
1695	>	}
1696	>	}
1697	>	if (binCount != 0)
1698	>	break;
1699	>	}
1700	>	else if ((fh = f.hash) == MOVED)
1701	>	tab = helpTransfer(tab, f);
1702	>	else if (fh == h &&                  // check first node
1703	>	((fk = f.key) == key || fk != null && key.equals(fk)) &&
1704	>	(fv = f.val) != null)
1705	>	return fv;
1706	>	else {
1707	>	boolean added = false;
1708	>	synchronized (f) {
1709	>	if (tabAt(tab, i) == f) {
1710	>	if (fh >= 0) {
1711	>	binCount = 1;
1712	>	for (Node<K,V> e = f;; ++binCount) {
1713	>	K ek;
1714	>	if (e.hash == h &&
1715	>	((ek = e.key) == key ||
1716	>	(ek != null && key.equals(ek)))) {
1717	>	val = e.val;
1718	>	break;
1719	>	}
1720	>	Node<K,V> pred = e;
1721	>	if ((e = e.next) == null) {
1722	>	if ((val = mappingFunction.apply(key)) != null) {
1723	>	if (pred.next != null)
1724	>	throw new IllegalStateException("Recursive update");
1725	>	added = true;
1726	>	pred.next = new Node<K,V>(h, key, val);
1727	>	}
1728	>	break;
1729	>	}
1730	>	}
1731	>	}
1732	>	else if (f instanceof TreeBin) {
1733	>	binCount = 2;
1734	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1735	>	TreeNode<K,V> r, p;
1736	>	if ((r = t.root) != null &&
1737	>	(p = r.findTreeNode(h, key, null)) != null)
1738	>	val = p.val;
1739	>	else if ((val = mappingFunction.apply(key)) != null) {
1740	>	added = true;
1741	>	t.putTreeVal(h, key, val);
1742	>	}
1743	>	}
1744	>	else if (f instanceof ReservationNode)
1745	>	throw new IllegalStateException("Recursive update");
1746	>	}
1747	>	}
1748	>	if (binCount != 0) {
1749	>	if (binCount >= TREEIFY_THRESHOLD)
1750	>	treeifyBin(tab, i);
1751	>	if (!added)
1752	>	return val;
1753	>	break;
1754	>	}
1755	>	}
1756	>	}
1757	>	if (val != null)
1758	>	addCount(1L, binCount);
1759	>	return val;
1760	>	}
1761	>
1762	>	/**
1763	>	* If the value for the specified key is present, attempts to
1764	>	* compute a new mapping given the key and its current mapped
1765	>	* value.  The entire method invocation is performed atomically.
1766	>	* Some attempted update operations on this map by other threads
1767	>	* may be blocked while computation is in progress, so the
1768	>	* computation should be short and simple, and must not attempt to
1769	>	* update any other mappings of this map.
1770	>	*
1771	>	* @param key key with which a value may be associated
1772	>	* @param remappingFunction the function to compute a value
1773	>	* @return the new value associated with the specified key, or null if none
1774	>	* @throws NullPointerException if the specified key or remappingFunction
1775	>	*         is null
1776	>	* @throws IllegalStateException if the computation detectably
1777	>	*         attempts a recursive update to this map that would
1778	>	*         otherwise never complete
1779	>	* @throws RuntimeException or Error if the remappingFunction does so,
1780	>	*         in which case the mapping is unchanged
1781	>	*/
1782	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1783	>	if (key == null || remappingFunction == null)
1784	>	throw new NullPointerException();
1785	>	int h = spread(key.hashCode());
1786	>	V val = null;
1787	>	int delta = 0;
1788	>	int binCount = 0;
1789	>	for (Node<K,V>[] tab = table;;) {
1790	>	Node<K,V> f; int n, i, fh;
1791	>	if (tab == null || (n = tab.length) == 0)
1792	>	tab = initTable();
1793	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1794	>	break;
1795	>	else if ((fh = f.hash) == MOVED)
1796	>	tab = helpTransfer(tab, f);
1797	>	else {
1798	>	synchronized (f) {
1799	>	if (tabAt(tab, i) == f) {
1800	>	if (fh >= 0) {
1801	>	binCount = 1;
1802	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1803	>	K ek;
1804	>	if (e.hash == h &&
1805	>	((ek = e.key) == key ||
1806	>	(ek != null && key.equals(ek)))) {
1807	>	val = remappingFunction.apply(key, e.val);
1808	>	if (val != null)
1809	>	e.val = val;
1810	>	else {
1811	>	delta = -1;
1812	>	Node<K,V> en = e.next;
1813	>	if (pred != null)
1814	>	pred.next = en;
1815	>	else
1816	>	setTabAt(tab, i, en);
1817	>	}
1818	>	break;
1819	>	}
1820	>	pred = e;
1821	>	if ((e = e.next) == null)
1822	>	break;
1823	>	}
1824	>	}
1825	>	else if (f instanceof TreeBin) {
1826	>	binCount = 2;
1827	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1828	>	TreeNode<K,V> r, p;
1829	>	if ((r = t.root) != null &&
1830	>	(p = r.findTreeNode(h, key, null)) != null) {
1831	>	val = remappingFunction.apply(key, p.val);
1832	>	if (val != null)
1833	>	p.val = val;
1834	>	else {
1835	>	delta = -1;
1836	>	if (t.removeTreeNode(p))
1837	>	setTabAt(tab, i, untreeify(t.first));
1838	>	}
1839	>	}
1840	>	}
1841	>	else if (f instanceof ReservationNode)
1842	>	throw new IllegalStateException("Recursive update");
1843	>	}
1844	>	}
1845	>	if (binCount != 0)
1846	>	break;
1847	>	}
1848	>	}
1849	>	if (delta != 0)
1850	>	addCount((long)delta, binCount);
1851	>	return val;
1852	>	}
1853	>
1854	>	/**
1855	>	* Attempts to compute a mapping for the specified key and its
1856	>	* current mapped value (or {@code null} if there is no current
1857	>	* mapping). The entire method invocation is performed atomically.
1858	>	* Some attempted update operations on this map by other threads
1859	>	* may be blocked while computation is in progress, so the
1860	>	* computation should be short and simple, and must not attempt to
1861	>	* update any other mappings of this Map.
1862	>	*
1863	>	* @param key key with which the specified value is to be associated
1864	>	* @param remappingFunction the function to compute a value
1865	>	* @return the new value associated with the specified key, or null if none
1866	>	* @throws NullPointerException if the specified key or remappingFunction
1867	>	*         is null
1868	>	* @throws IllegalStateException if the computation detectably
1869	>	*         attempts a recursive update to this map that would
1870	>	*         otherwise never complete
1871	>	* @throws RuntimeException or Error if the remappingFunction does so,
1872	>	*         in which case the mapping is unchanged
1873	>	*/
1874	>	public V compute(K key,
1875	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1876	>	if (key == null || remappingFunction == null)
1877	>	throw new NullPointerException();
1878	>	int h = spread(key.hashCode());
1879	>	V val = null;
1880	>	int delta = 0;
1881	>	int binCount = 0;
1882	>	for (Node<K,V>[] tab = table;;) {
1883	>	Node<K,V> f; int n, i, fh;
1884	>	if (tab == null || (n = tab.length) == 0)
1885	>	tab = initTable();
1886	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1887	>	Node<K,V> r = new ReservationNode<K,V>();
1888	>	synchronized (r) {
1889	>	if (casTabAt(tab, i, null, r)) {
1890	>	binCount = 1;
1891	>	Node<K,V> node = null;
1892	>	try {
1893	>	if ((val = remappingFunction.apply(key, null)) != null) {
1894	>	delta = 1;
1895	>	node = new Node<K,V>(h, key, val);
1896	>	}
1897	>	} finally {
1898	>	setTabAt(tab, i, node);
1899	>	}
1900	>	}
1901	>	}
1902	>	if (binCount != 0)
1903	>	break;
1904	>	}
1905	>	else if ((fh = f.hash) == MOVED)
1906	>	tab = helpTransfer(tab, f);
1907	>	else {
1908	>	synchronized (f) {
1909	>	if (tabAt(tab, i) == f) {
1910	>	if (fh >= 0) {
1911	>	binCount = 1;
1912	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1913	>	K ek;
1914	>	if (e.hash == h &&
1915	>	((ek = e.key) == key ||
1916	>	(ek != null && key.equals(ek)))) {
1917	>	val = remappingFunction.apply(key, e.val);
1918	>	if (val != null)
1919	>	e.val = val;
1920	>	else {
1921	>	delta = -1;
1922	>	Node<K,V> en = e.next;
1923	>	if (pred != null)
1924	>	pred.next = en;
1925	>	else
1926	>	setTabAt(tab, i, en);
1927	>	}
1928	>	break;
1929	>	}
1930	>	pred = e;
1931	>	if ((e = e.next) == null) {
1932	>	val = remappingFunction.apply(key, null);
1933	>	if (val != null) {
1934	>	if (pred.next != null)
1935	>	throw new IllegalStateException("Recursive update");
1936	>	delta = 1;
1937	>	pred.next = new Node<K,V>(h, key, val);
1938	>	}
1939	>	break;
1940	>	}
1941	>	}
1942	>	}
1943	>	else if (f instanceof TreeBin) {
1944	>	binCount = 1;
1945	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1946	>	TreeNode<K,V> r, p;
1947	>	if ((r = t.root) != null)
1948	>	p = r.findTreeNode(h, key, null);
1949	>	else
1950	>	p = null;
1951	>	V pv = (p == null) ? null : p.val;
1952	>	val = remappingFunction.apply(key, pv);
1953	>	if (val != null) {
1954	>	if (p != null)
1955	>	p.val = val;
1956	>	else {
1957	>	delta = 1;
1958	>	t.putTreeVal(h, key, val);
1959	>	}
1960	>	}
1961	>	else if (p != null) {
1962	>	delta = -1;
1963	>	if (t.removeTreeNode(p))
1964	>	setTabAt(tab, i, untreeify(t.first));
1965	>	}
1966	>	}
1967	>	else if (f instanceof ReservationNode)
1968	>	throw new IllegalStateException("Recursive update");
1969	>	}
1970	>	}
1971	>	if (binCount != 0) {
1972	>	if (binCount >= TREEIFY_THRESHOLD)
1973	>	treeifyBin(tab, i);
1974	>	break;
1975	>	}
1976	>	}
1977	>	}
1978	>	if (delta != 0)
1979	>	addCount((long)delta, binCount);
1980	>	return val;
1981	>	}
1982	>
1983	>	/**
1984	>	* If the specified key is not already associated with a
1985	>	* (non-null) value, associates it with the given value.
1986	>	* Otherwise, replaces the value with the results of the given
1987	>	* remapping function, or removes if {@code null}. The entire
1988	>	* method invocation is performed atomically.  Some attempted
1989	>	* update operations on this map by other threads may be blocked
1990	>	* while computation is in progress, so the computation should be
1991	>	* short and simple, and must not attempt to update any other
1992	>	* mappings of this Map.
1993	>	*
1994	>	* @param key key with which the specified value is to be associated
1995	>	* @param value the value to use if absent
1996	>	* @param remappingFunction the function to recompute a value if present
1997	>	* @return the new value associated with the specified key, or null if none
1998	>	* @throws NullPointerException if the specified key or the
1999	>	*         remappingFunction is null
2000	>	* @throws RuntimeException or Error if the remappingFunction does so,
2001	>	*         in which case the mapping is unchanged
2002	>	*/
2003	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2004	>	if (key == null || value == null || remappingFunction == null)
2005	>	throw new NullPointerException();
2006	>	int h = spread(key.hashCode());
2007	>	V val = null;
2008	>	int delta = 0;
2009	>	int binCount = 0;
2010	>	for (Node<K,V>[] tab = table;;) {
2011	>	Node<K,V> f; int n, i, fh;
2012	>	if (tab == null || (n = tab.length) == 0)
2013	>	tab = initTable();
2014	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
2015	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value))) {
2016	>	delta = 1;
2017	>	val = value;
2018	>	break;
2019	>	}
2020	>	}
2021	>	else if ((fh = f.hash) == MOVED)
2022	>	tab = helpTransfer(tab, f);
2023	>	else {
2024	>	synchronized (f) {
2025	>	if (tabAt(tab, i) == f) {
2026	>	if (fh >= 0) {
2027	>	binCount = 1;
2028	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2029	>	K ek;
2030	>	if (e.hash == h &&
2031	>	((ek = e.key) == key ||
2032	>	(ek != null && key.equals(ek)))) {
2033	>	val = remappingFunction.apply(e.val, value);
2034	>	if (val != null)
2035	>	e.val = val;
2036	>	else {
2037	>	delta = -1;
2038	>	Node<K,V> en = e.next;
2039	>	if (pred != null)
2040	>	pred.next = en;
2041	>	else
2042	>	setTabAt(tab, i, en);
2043	>	}
2044	>	break;
2045	>	}
2046	>	pred = e;
2047	>	if ((e = e.next) == null) {
2048	>	delta = 1;
2049	>	val = value;
2050	>	pred.next = new Node<K,V>(h, key, val);
2051	>	break;
2052	>	}
2053	>	}
2054	>	}
2055	>	else if (f instanceof TreeBin) {
2056	>	binCount = 2;
2057	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2058	>	TreeNode<K,V> r = t.root;
2059	>	TreeNode<K,V> p = (r == null) ? null :
2060	>	r.findTreeNode(h, key, null);
2061	>	val = (p == null) ? value :
2062	>	remappingFunction.apply(p.val, value);
2063	>	if (val != null) {
2064	>	if (p != null)
2065	>	p.val = val;
2066	>	else {
2067	>	delta = 1;
2068	>	t.putTreeVal(h, key, val);
2069	>	}
2070	>	}
2071	>	else if (p != null) {
2072	>	delta = -1;
2073	>	if (t.removeTreeNode(p))
2074	>	setTabAt(tab, i, untreeify(t.first));
2075	>	}
2076	>	}
2077	>	else if (f instanceof ReservationNode)
2078	>	throw new IllegalStateException("Recursive update");
2079	>	}
2080	>	}
2081	>	if (binCount != 0) {
2082	>	if (binCount >= TREEIFY_THRESHOLD)
2083	>	treeifyBin(tab, i);
2084	>	break;
2085	>	}
2086	>	}
2087	>	}
2088	>	if (delta != 0)
2089	>	addCount((long)delta, binCount);
2090	>	return val;
2091	>	}
2092	>
2093	>	// Hashtable legacy methods
2094	>
2095	>	/**
2096	>	* Tests if some key maps into the specified value in this table.
2097	>	*
2098	>	* <p>Note that this method is identical in functionality to
2099	>	* {@link #containsValue(Object)}, and exists solely to ensure
2100	>	* full compatibility with class {@link java.util.Hashtable},
2101	>	* which supported this method prior to introduction of the
2102	>	* Java Collections Framework.
2103	>	*
2104	>	* @param  value a value to search for
2105	>	* @return {@code true} if and only if some key maps to the
2106	>	*         {@code value} argument in this table as
2107	>	*         determined by the {@code equals} method;
2108	>	*         {@code false} otherwise
2109	>	* @throws NullPointerException if the specified value is null
2110	>	*/
2111	>	public boolean contains(Object value) {
2112	>	return containsValue(value);
2113	>	}
2114	>
2115	>	/**
2116	>	* Returns an enumeration of the keys in this table.
2117	>	*
2118	>	* @return an enumeration of the keys in this table
2119	>	* @see #keySet()
2120	>	*/
2121	>	public Enumeration<K> keys() {
2122	>	Node<K,V>[] t;
2123	>	int f = (t = table) == null ? 0 : t.length;
2124	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2125	>	}
2126	>
2127	>	/**
2128	>	* Returns an enumeration of the values in this table.
2129	>	*
2130	>	* @return an enumeration of the values in this table
2131	>	* @see #values()
2132	>	*/
2133	>	public Enumeration<V> elements() {
2134	>	Node<K,V>[] t;
2135	>	int f = (t = table) == null ? 0 : t.length;
2136	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2137	>	}
2138	>
2139	>	// ConcurrentHashMap-only methods
2140	>
2141	>	/**
2142	>	* Returns the number of mappings. This method should be used
2143	>	* instead of {@link #size} because a ConcurrentHashMap may
2144	>	* contain more mappings than can be represented as an int. The
2145	>	* value returned is an estimate; the actual count may differ if
2146	>	* there are concurrent insertions or removals.
2147	>	*
2148	>	* @return the number of mappings
2149	>	* @since 1.8
2150	>	*/
2151	>	public long mappingCount() {
2152	>	long n = sumCount();
2153	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2154	>	}
2155	>
2156	>	/**
2157	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2158	>	* from the given type to {@code Boolean.TRUE}.
2159	>	*
2160	>	* @param <K> the element type of the returned set
2161	>	* @return the new set
2162	>	* @since 1.8
2163	>	*/
2164	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2165	>	return new KeySetView<K,Boolean>
2166	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2167	>	}
2168	>
2169	>	/**
2170	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2171	>	* from the given type to {@code Boolean.TRUE}.
2172	>	*
2173	>	* @param initialCapacity The implementation performs internal
2174	>	* sizing to accommodate this many elements.
2175	>	* @param <K> the element type of the returned set
2176	>	* @return the new set
2177	>	* @throws IllegalArgumentException if the initial capacity of
2178	>	* elements is negative
2179	>	* @since 1.8
2180	>	*/
2181	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2182	>	return new KeySetView<K,Boolean>
2183	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2184	>	}
2185	>
2186	>	/**
2187	>	* Returns a {@link Set} view of the keys in this map, using the
2188	>	* given common mapped value for any additions (i.e., {@link
2189	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2190	>	* This is of course only appropriate if it is acceptable to use
2191	>	* the same value for all additions from this view.
2192	>	*
2193	>	* @param mappedValue the mapped value to use for any additions
2194	>	* @return the set view
2195	>	* @throws NullPointerException if the mappedValue is null
2196	>	*/
2197	>	public KeySetView<K,V> keySet(V mappedValue) {
2198	>	if (mappedValue == null)
2199	>	throw new NullPointerException();
2200	>	return new KeySetView<K,V>(this, mappedValue);
2201	>	}
2202	>
2203	>	/* ---------------- Special Nodes -------------- */
2204	>
2205	>	/**
2206	>	* A node inserted at head of bins during transfer operations.
2207	>	*/
2208	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2209	>	final Node<K,V>[] nextTable;
2210	>	ForwardingNode(Node<K,V>[] tab) {
2211	>	super(MOVED, null, null);
2212	>	this.nextTable = tab;
2213	>	}
2214	>
2215	>	Node<K,V> find(int h, Object k) {
2216	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2217	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2218	>	Node<K,V> e; int n;
2219	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2220	>	(e = tabAt(tab, (n - 1) & h)) == null)
2221	>	return null;
2222	>	for (;;) {
2223	>	int eh; K ek;
2224	>	if ((eh = e.hash) == h &&
2225	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2226	>	return e;
2227	>	if (eh < 0) {
2228	>	if (e instanceof ForwardingNode) {
2229	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2230	>	continue outer;
2231	>	}
2232	>	else
2233	>	return e.find(h, k);
2234	>	}
2235	>	if ((e = e.next) == null)
2236	>	return null;
2237	>	}
2238	>	}
2239	>	}
2240	>	}
2241	>
2242	>	/**
2243	>	* A place-holder node used in computeIfAbsent and compute.
2244	>	*/
2245	>	static final class ReservationNode<K,V> extends Node<K,V> {
2246	>	ReservationNode() {
2247	>	super(RESERVED, null, null);
2248	>	}
2249	>
2250	>	Node<K,V> find(int h, Object k) {
2251	>	return null;
2252	>	}
2253	>	}
2254	>
2255	>	/* ---------------- Table Initialization and Resizing -------------- */
2256	>
2257	>	/**
2258	>	* Returns the stamp bits for resizing a table of size n.
2259	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2260	>	*/
2261	>	static final int resizeStamp(int n) {
2262	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2263	>	}
2264	>
2265	>	/**
2266	>	* Initializes table, using the size recorded in sizeCtl.
2267	>	*/
2268	>	private final Node<K,V>[] initTable() {
2269	>	Node<K,V>[] tab; int sc;
2270	>	while ((tab = table) == null || tab.length == 0) {
2271	>	if ((sc = sizeCtl) < 0)
2272	>	Thread.yield(); // lost initialization race; just spin
2273	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2274	>	try {
2275	>	if ((tab = table) == null || tab.length == 0) {
2276	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2277	>	@SuppressWarnings("unchecked")
2278	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2279	>	table = tab = nt;
2280	>	sc = n - (n >>> 2);
2281	>	}
2282	>	} finally {
2283	>	sizeCtl = sc;
2284	>	}
2285	>	break;
2286	>	}
2287	>	}
2288	>	return tab;
2289	>	}
2290	>
2291	>	/**
2292	>	* Adds to count, and if table is too small and not already
2293	>	* resizing, initiates transfer. If already resizing, helps
2294	>	* perform transfer if work is available.  Rechecks occupancy
2295	>	* after a transfer to see if another resize is already needed
2296	>	* because resizings are lagging additions.
2297	>	*
2298	>	* @param x the count to add
2299	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2300	>	*/
2301	>	private final void addCount(long x, int check) {
2302	>	CounterCell[] as; long b, s;
2303	>	if ((as = counterCells) != null ||
2304	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2305	>	CounterCell a; long v; int m;
2306	>	boolean uncontended = true;
2307	>	if (as == null || (m = as.length - 1) < 0 ||
2308	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2309	>	!(uncontended =
2310	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2311	>	fullAddCount(x, uncontended);
2312	>	return;
2313	>	}
2314	>	if (check <= 1)
2315	>	return;
2316	>	s = sumCount();
2317	>	}
2318	>	if (check >= 0) {
2319	>	Node<K,V>[] tab, nt; int n, sc;
2320	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2321	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2322	>	int rs = resizeStamp(n);
2323	>	if (sc < 0) {
2324	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2325	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2326	>	transferIndex <= 0)
2327	>	break;
2328	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2329	>	transfer(tab, nt);
2330	>	}
2331	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2332	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2333	>	transfer(tab, null);
2334	>	s = sumCount();
2335	>	}
2336	>	}
2337	>	}
2338	>
2339	>	/**
2340	>	* Helps transfer if a resize is in progress.
2341	>	*/
2342	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2343	>	Node<K,V>[] nextTab; int sc;
2344	>	if (tab != null && (f instanceof ForwardingNode) &&
2345	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2346	>	int rs = resizeStamp(tab.length);
2347	>	while (nextTab == nextTable && table == tab &&
2348	>	(sc = sizeCtl) < 0) {
2349	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2350	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2351	>	break;
2352	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2353	>	transfer(tab, nextTab);
2354	>	break;
2355	>	}
2356	>	}
2357	>	return nextTab;
2358	>	}
2359	>	return table;
2360	>	}
2361	>
2362	>	/**
2363	>	* Tries to presize table to accommodate the given number of elements.
2364	>	*
2365	>	* @param size number of elements (doesn't need to be perfectly accurate)
2366	>	*/
2367	>	private final void tryPresize(int size) {
2368	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2369	>	tableSizeFor(size + (size >>> 1) + 1);
2370	>	int sc;
2371	>	while ((sc = sizeCtl) >= 0) {
2372	>	Node<K,V>[] tab = table; int n;
2373	>	if (tab == null || (n = tab.length) == 0) {
2374	>	n = (sc > c) ? sc : c;
2375	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2376	>	try {
2377	>	if (table == tab) {
2378	>	@SuppressWarnings("unchecked")
2379	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2380	>	table = nt;
2381	>	sc = n - (n >>> 2);
2382	>	}
2383	>	} finally {
2384	>	sizeCtl = sc;
2385	>	}
2386	>	}
2387	>	}
2388	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2389	>	break;
2390	>	else if (tab == table) {
2391	>	int rs = resizeStamp(n);
2392	>	if (U.compareAndSwapInt(this, SIZECTL, sc,
2393	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2394	>	transfer(tab, null);
2395	>	}
2396	>	}
2397	>	}
2398	>
2399	>	/**
2400	>	* Moves and/or copies the nodes in each bin to new table. See
2401	>	* above for explanation.
2402	>	*/
2403	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2404	>	int n = tab.length, stride;
2405	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2406	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2407	>	if (nextTab == null) {            // initiating
2408	>	try {
2409	>	@SuppressWarnings("unchecked")
2410	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2411	>	nextTab = nt;
2412	>	} catch (Throwable ex) {      // try to cope with OOME
2413	>	sizeCtl = Integer.MAX_VALUE;
2414	>	return;
2415	>	}
2416	>	nextTable = nextTab;
2417	>	transferIndex = n;
2418	>	}
2419	>	int nextn = nextTab.length;
2420	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2421	>	boolean advance = true;
2422	>	boolean finishing = false; // to ensure sweep before committing nextTab
2423	>	for (int i = 0, bound = 0;;) {
2424	>	Node<K,V> f; int fh;
2425	>	while (advance) {
2426	>	int nextIndex, nextBound;
2427	>	if (--i >= bound || finishing)
2428	>	advance = false;
2429	>	else if ((nextIndex = transferIndex) <= 0) {
2430	>	i = -1;
2431	>	advance = false;
2432	>	}
2433	>	else if (U.compareAndSwapInt
2434	>	(this, TRANSFERINDEX, nextIndex,
2435	>	nextBound = (nextIndex > stride ?
2436	>	nextIndex - stride : 0))) {
2437	>	bound = nextBound;
2438	>	i = nextIndex - 1;
2439	>	advance = false;
2440	>	}
2441	>	}
2442	>	if (i < 0 || i >= n || i + n >= nextn) {
2443	>	int sc;
2444	>	if (finishing) {
2445	>	nextTable = null;
2446	>	table = nextTab;
2447	>	sizeCtl = (n << 1) - (n >>> 1);
2448	>	return;
2449	>	}
2450	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2451	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2452	>	return;
2453	>	finishing = advance = true;
2454	>	i = n; // recheck before commit
2455	>	}
2456	>	}
2457	>	else if ((f = tabAt(tab, i)) == null)
2458	>	advance = casTabAt(tab, i, null, fwd);
2459	>	else if ((fh = f.hash) == MOVED)
2460	>	advance = true; // already processed
2461	>	else {
2462	>	synchronized (f) {
2463	>	if (tabAt(tab, i) == f) {
2464	>	Node<K,V> ln, hn;
2465	>	if (fh >= 0) {
2466	>	int runBit = fh & n;
2467	>	Node<K,V> lastRun = f;
2468	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2469	>	int b = p.hash & n;
2470	>	if (b != runBit) {
2471	>	runBit = b;
2472	>	lastRun = p;
2473	>	}
2474	>	}
2475	>	if (runBit == 0) {
2476	>	ln = lastRun;
2477	>	hn = null;
2478	>	}
2479	>	else {
2480	>	hn = lastRun;
2481	>	ln = null;
2482	>	}
2483	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2484	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2485	>	if ((ph & n) == 0)
2486	>	ln = new Node<K,V>(ph, pk, pv, ln);
2487	>	else
2488	>	hn = new Node<K,V>(ph, pk, pv, hn);
2489	>	}
2490	>	setTabAt(nextTab, i, ln);
2491	>	setTabAt(nextTab, i + n, hn);
2492	>	setTabAt(tab, i, fwd);
2493	>	advance = true;
2494	>	}
2495	>	else if (f instanceof TreeBin) {
2496	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2497	>	TreeNode<K,V> lo = null, loTail = null;
2498	>	TreeNode<K,V> hi = null, hiTail = null;
2499	>	int lc = 0, hc = 0;
2500	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2501	>	int h = e.hash;
2502	>	TreeNode<K,V> p = new TreeNode<K,V>
2503	>	(h, e.key, e.val, null, null);
2504	>	if ((h & n) == 0) {
2505	>	if ((p.prev = loTail) == null)
2506	>	lo = p;
2507	>	else
2508	>	loTail.next = p;
2509	>	loTail = p;
2510	>	++lc;
2511	>	}
2512	>	else {
2513	>	if ((p.prev = hiTail) == null)
2514	>	hi = p;
2515	>	else
2516	>	hiTail.next = p;
2517	>	hiTail = p;
2518	>	++hc;
2519	>	}
2520	>	}
2521	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2522	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2523	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2524	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2525	>	setTabAt(nextTab, i, ln);
2526	>	setTabAt(nextTab, i + n, hn);
2527	>	setTabAt(tab, i, fwd);
2528	>	advance = true;
2529	>	}
2530	>	}
2531	>	}
2532	>	}
2533	>	}
2534	>	}
2535	>
2536	>	/* ---------------- Counter support -------------- */
2537	>
2538	>	/**
2539	>	* A padded cell for distributing counts.  Adapted from LongAdder
2540	>	* and Striped64.  See their internal docs for explanation.
2541	>	*/
2542	>	@jdk.internal.vm.annotation.Contended static final class CounterCell {
2543	>	volatile long value;
2544	>	CounterCell(long x) { value = x; }
2545	>	}
2546	>
2547	>	final long sumCount() {
2548	>	CounterCell[] as = counterCells; CounterCell a;
2549	>	long sum = baseCount;
2550	>	if (as != null) {
2551	>	for (int i = 0; i < as.length; ++i) {
2552	>	if ((a = as[i]) != null)
2553	>	sum += a.value;
2554	>	}
2555	>	}
2556	>	return sum;
2557	>	}
2558	>
2559	>	// See LongAdder version for explanation
2560	>	private final void fullAddCount(long x, boolean wasUncontended) {
2561	>	int h;
2562	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2563	>	ThreadLocalRandom.localInit();      // force initialization
2564	>	h = ThreadLocalRandom.getProbe();
2565	>	wasUncontended = true;
2566	>	}
2567	>	boolean collide = false;                // True if last slot nonempty
2568	>	for (;;) {
2569	>	CounterCell[] as; CounterCell a; int n; long v;
2570	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2571	>	if ((a = as[(n - 1) & h]) == null) {
2572	>	if (cellsBusy == 0) {            // Try to attach new Cell
2573	>	CounterCell r = new CounterCell(x); // Optimistic create
2574	>	if (cellsBusy == 0 &&
2575	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2576	>	boolean created = false;
2577	>	try {               // Recheck under lock
2578	>	CounterCell[] rs; int m, j;
2579	>	if ((rs = counterCells) != null &&
2580	>	(m = rs.length) > 0 &&
2581	>	rs[j = (m - 1) & h] == null) {
2582	>	rs[j] = r;
2583	>	created = true;
2584	>	}
2585	>	} finally {
2586	>	cellsBusy = 0;
2587	>	}
2588	>	if (created)
2589	>	break;
2590	>	continue;           // Slot is now non-empty
2591	>	}
2592	>	}
2593	>	collide = false;
2594	>	}
2595	>	else if (!wasUncontended)       // CAS already known to fail
2596	>	wasUncontended = true;      // Continue after rehash
2597	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2598	>	break;
2599	>	else if (counterCells != as || n >= NCPU)
2600	>	collide = false;            // At max size or stale
2601	>	else if (!collide)
2602	>	collide = true;
2603	>	else if (cellsBusy == 0 &&
2604	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2605	>	try {
2606	>	if (counterCells == as) {// Expand table unless stale
2607	>	CounterCell[] rs = new CounterCell[n << 1];
2608	>	for (int i = 0; i < n; ++i)
2609	>	rs[i] = as[i];
2610	>	counterCells = rs;
2611	>	}
2612	>	} finally {
2613	>	cellsBusy = 0;
2614	>	}
2615	>	collide = false;
2616	>	continue;                   // Retry with expanded table
2617	>	}
2618	>	h = ThreadLocalRandom.advanceProbe(h);
2619	>	}
2620	>	else if (cellsBusy == 0 && counterCells == as &&
2621	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2622	>	boolean init = false;
2623	>	try {                           // Initialize table
2624	>	if (counterCells == as) {
2625	>	CounterCell[] rs = new CounterCell[2];
2626	>	rs[h & 1] = new CounterCell(x);
2627	>	counterCells = rs;
2628	>	init = true;
2629	>	}
2630	>	} finally {
2631	>	cellsBusy = 0;
2632	>	}
2633	>	if (init)
2634	>	break;
2635	>	}
2636	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2637	>	break;                          // Fall back on using base
2638	>	}
2639	>	}
2640	>
2641	>	/* ---------------- Conversion from/to TreeBins -------------- */
2642	>
2643	>	/**
2644	>	* Replaces all linked nodes in bin at given index unless table is
2645	>	* too small, in which case resizes instead.
2646	>	*/
2647	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2648	>	Node<K,V> b; int n;
2649	>	if (tab != null) {
2650	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2651	>	tryPresize(n << 1);
2652	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2653	>	synchronized (b) {
2654	>	if (tabAt(tab, index) == b) {
2655	>	TreeNode<K,V> hd = null, tl = null;
2656	>	for (Node<K,V> e = b; e != null; e = e.next) {
2657	>	TreeNode<K,V> p =
2658	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2659	>	null, null);
2660	>	if ((p.prev = tl) == null)
2661	>	hd = p;
2662	>	else
2663	>	tl.next = p;
2664	>	tl = p;
2665	>	}
2666	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2667	>	}
2668	>	}
2669	>	}
2670	>	}
2671	>	}
2672	>
2673	>	/**
2674	>	* Returns a list of non-TreeNodes replacing those in given list.
2675	>	*/
2676	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2677	>	Node<K,V> hd = null, tl = null;
2678	>	for (Node<K,V> q = b; q != null; q = q.next) {
2679	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val);
2680	>	if (tl == null)
2681	>	hd = p;
2682	>	else
2683	>	tl.next = p;
2684	>	tl = p;
2685	>	}
2686	>	return hd;
2687	>	}
2688	>
2689	>	/* ---------------- TreeNodes -------------- */
2690	>
2691	>	/**
2692	>	* Nodes for use in TreeBins.
2693	>	*/
2694	>	static final class TreeNode<K,V> extends Node<K,V> {
2695	>	TreeNode<K,V> parent;  // red-black tree links
2696	>	TreeNode<K,V> left;
2697	>	TreeNode<K,V> right;
2698	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2699	>	boolean red;
2700	>
2701	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2702	>	TreeNode<K,V> parent) {
2703	>	super(hash, key, val, next);
2704	>	this.parent = parent;
2705	>	}
2706	>
2707	>	Node<K,V> find(int h, Object k) {
2708	>	return findTreeNode(h, k, null);
2709	>	}
2710
2711		/**
2712	<	* Number of updates; used for checking lack of modifications
2713	<	* in bulk-read methods.
2712	>	* Returns the TreeNode (or null if not found) for the given key
2713	>	* starting at given root.
2714		*/
2715	<	transient int modCount;
2715	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2716	>	if (k != null) {
2717	>	TreeNode<K,V> p = this;
2718	>	do {
2719	>	int ph, dir; K pk; TreeNode<K,V> q;
2720	>	TreeNode<K,V> pl = p.left, pr = p.right;
2721	>	if ((ph = p.hash) > h)
2722	>	p = pl;
2723	>	else if (ph < h)
2724	>	p = pr;
2725	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2726	>	return p;
2727	>	else if (pl == null)
2728	>	p = pr;
2729	>	else if (pr == null)
2730	>	p = pl;
2731	>	else if ((kc != null ||
2732	>	(kc = comparableClassFor(k)) != null) &&
2733	>	(dir = compareComparables(kc, k, pk)) != 0)
2734	>	p = (dir < 0) ? pl : pr;
2735	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2736	>	return q;
2737	>	else
2738	>	p = pl;
2739	>	} while (p != null);
2740	>	}
2741	>	return null;
2742	>	}
2743	>	}
2744	>
2745	>	/* ---------------- TreeBins -------------- */
2746	>
2747	>	/**
2748	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2749	>	* keys or values, but instead point to list of TreeNodes and
2750	>	* their root. They also maintain a parasitic read-write lock
2751	>	* forcing writers (who hold bin lock) to wait for readers (who do
2752	>	* not) to complete before tree restructuring operations.
2753	>	*/
2754	>	static final class TreeBin<K,V> extends Node<K,V> {
2755	>	TreeNode<K,V> root;
2756	>	volatile TreeNode<K,V> first;
2757	>	volatile Thread waiter;
2758	>	volatile int lockState;
2759	>	// values for lockState
2760	>	static final int WRITER = 1; // set while holding write lock
2761	>	static final int WAITER = 2; // set when waiting for write lock
2762	>	static final int READER = 4; // increment value for setting read lock
2763
2764		/**
2765	<	* The table is rehashed when its size exceeds this threshold.
2766	<	* (The value of this field is always (int)(capacity *
2767	<	* loadFactor).)
2765	>	* Tie-breaking utility for ordering insertions when equal
2766	>	* hashCodes and non-comparable. We don't require a total
2767	>	* order, just a consistent insertion rule to maintain
2768	>	* equivalence across rebalancings. Tie-breaking further than
2769	>	* necessary simplifies testing a bit.
2770		*/
2771	<	private transient int threshold;
2771	>	static int tieBreakOrder(Object a, Object b) {
2772	>	int d;
2773	>	if (a == null || b == null ||
2774	>	(d = a.getClass().getName().
2775	>	compareTo(b.getClass().getName())) == 0)
2776	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2777	>	-1 : 1);
2778	>	return d;
2779	>	}
2780
2781		/**
2782	<	* The per-segment table
2782	>	* Creates bin with initial set of nodes headed by b.
2783		*/
2784	<	transient HashEntry[] table;
2784	>	TreeBin(TreeNode<K,V> b) {
2785	>	super(TREEBIN, null, null);
2786	>	this.first = b;
2787	>	TreeNode<K,V> r = null;
2788	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2789	>	next = (TreeNode<K,V>)x.next;
2790	>	x.left = x.right = null;
2791	>	if (r == null) {
2792	>	x.parent = null;
2793	>	x.red = false;
2794	>	r = x;
2795	>	}
2796	>	else {
2797	>	K k = x.key;
2798	>	int h = x.hash;
2799	>	Class<?> kc = null;
2800	>	for (TreeNode<K,V> p = r;;) {
2801	>	int dir, ph;
2802	>	K pk = p.key;
2803	>	if ((ph = p.hash) > h)
2804	>	dir = -1;
2805	>	else if (ph < h)
2806	>	dir = 1;
2807	>	else if ((kc == null &&
2808	>	(kc = comparableClassFor(k)) == null) ||
2809	>	(dir = compareComparables(kc, k, pk)) == 0)
2810	>	dir = tieBreakOrder(k, pk);
2811	>	TreeNode<K,V> xp = p;
2812	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2813	>	x.parent = xp;
2814	>	if (dir <= 0)
2815	>	xp.left = x;
2816	>	else
2817	>	xp.right = x;
2818	>	r = balanceInsertion(r, x);
2819	>	break;
2820	>	}
2821	>	}
2822	>	}
2823	>	}
2824	>	this.root = r;
2825	>	assert checkInvariants(root);
2826	>	}
2827
2828		/**
2829	<	* The load factor for the hash table.  Even though this value
225	<	* is same for all segments, it is replicated to avoid needing
226	<	* links to outer object.
227	<	* @serial
2829	>	* Acquires write lock for tree restructuring.
2830		*/
2831	<	private final float loadFactor;
2832	<
2833	<	Segment(int initialCapacity, float lf) {
232	<	loadFactor = lf;
233	<	setTable(new HashEntry[initialCapacity]);
2831	>	private final void lockRoot() {
2832	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2833	>	contendedLock(); // offload to separate method
2834		}
2835
2836		/**
2837	<	* Set table to new HashEntry array.
2838	<	* Call only while holding lock or in constructor.
2839	<	**/
2840	<	private void setTable(HashEntry[] newTable) {
241	<	table = newTable;
242	<	threshold = (int)(newTable.length * loadFactor);
243	<	count = count; // write-volatile
2837	>	* Releases write lock for tree restructuring.
2838	>	*/
2839	>	private final void unlockRoot() {
2840	>	lockState = 0;
2841		}
2842
2843	<	/* Specialized implementations of map methods */
2844	<
2845	<	V get(K key, int hash) {
2846	<	if (count != 0) { // read-volatile
2847	<	HashEntry[] tab = table;
2848	<	int index = hash & (tab.length - 1);
2849	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
2850	<	while (e != null) {
2851	<	if (e.hash == hash && key.equals(e.key))
2852	<	return e.value;
2853	<	e = e.next;
2843	>	/**
2844	>	* Possibly blocks awaiting root lock.
2845	>	*/
2846	>	private final void contendedLock() {
2847	>	boolean waiting = false;
2848	>	for (int s;;) {
2849	>	if (((s = lockState) & ~WAITER) == 0) {
2850	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2851	>	if (waiting)
2852	>	waiter = null;
2853	>	return;
2854	>	}
2855	>	}
2856	>	else if ((s & WAITER) == 0) {
2857	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2858	>	waiting = true;
2859	>	waiter = Thread.currentThread();
2860	>	}
2861		}
2862	+	else if (waiting)
2863	+	LockSupport.park(this);
2864		}
259	–	return null;
2865		}
2866
2867	<	boolean containsKey(Object key, int hash) {
2868	<	if (count != 0) { // read-volatile
2869	<	HashEntry[] tab = table;
2870	<	int index = hash & (tab.length - 1);
2871	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
2872	<	while (e != null) {
2873	<	if (e.hash == hash && key.equals(e.key))
2874	<	return true;
2875	<	e = e.next;
2867	>	/**
2868	>	* Returns matching node or null if none. Tries to search
2869	>	* using tree comparisons from root, but continues linear
2870	>	* search when lock not available.
2871	>	*/
2872	>	final Node<K,V> find(int h, Object k) {
2873	>	if (k != null) {
2874	>	for (Node<K,V> e = first; e != null; ) {
2875	>	int s; K ek;
2876	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2877	>	if (e.hash == h &&
2878	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2879	>	return e;
2880	>	e = e.next;
2881	>	}
2882	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2883	>	s + READER)) {
2884	>	TreeNode<K,V> r, p;
2885	>	try {
2886	>	p = ((r = root) == null ? null :
2887	>	r.findTreeNode(h, k, null));
2888	>	} finally {
2889	>	Thread w;
2890	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2891	>	(READER|WAITER) && (w = waiter) != null)
2892	>	LockSupport.unpark(w);
2893	>	}
2894	>	return p;
2895	>	}
2896		}
2897		}
2898	<	return false;
2898	>	return null;
2899		}
2900
2901	<	boolean containsValue(Object value) {
2902	<	if (count != 0) { // read-volatile
2903	<	HashEntry[] tab = table;
2904	<	int len = tab.length;
2905	<	for (int i = 0 ; i < len; i++)
2906	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i] ; e != null ; e = e.next)
2907	<	if (value.equals(e.value))
2908	<	return true;
2901	>	/**
2902	>	* Finds or adds a node.
2903	>	* @return null if added
2904	>	*/
2905	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2906	>	Class<?> kc = null;
2907	>	boolean searched = false;
2908	>	for (TreeNode<K,V> p = root;;) {
2909	>	int dir, ph; K pk;
2910	>	if (p == null) {
2911	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2912	>	break;
2913	>	}
2914	>	else if ((ph = p.hash) > h)
2915	>	dir = -1;
2916	>	else if (ph < h)
2917	>	dir = 1;
2918	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2919	>	return p;
2920	>	else if ((kc == null &&
2921	>	(kc = comparableClassFor(k)) == null) ||
2922	>	(dir = compareComparables(kc, k, pk)) == 0) {
2923	>	if (!searched) {
2924	>	TreeNode<K,V> q, ch;
2925	>	searched = true;
2926	>	if (((ch = p.left) != null &&
2927	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2928	>	((ch = p.right) != null &&
2929	>	(q = ch.findTreeNode(h, k, kc)) != null))
2930	>	return q;
2931	>	}
2932	>	dir = tieBreakOrder(k, pk);
2933	>	}
2934	>
2935	>	TreeNode<K,V> xp = p;
2936	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2937	>	TreeNode<K,V> x, f = first;
2938	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2939	>	if (f != null)
2940	>	f.prev = x;
2941	>	if (dir <= 0)
2942	>	xp.left = x;
2943	>	else
2944	>	xp.right = x;
2945	>	if (!xp.red)
2946	>	x.red = true;
2947	>	else {
2948	>	lockRoot();
2949	>	try {
2950	>	root = balanceInsertion(root, x);
2951	>	} finally {
2952	>	unlockRoot();
2953	>	}
2954	>	}
2955	>	break;
2956	>	}
2957		}
2958	<	return false;
2958	>	assert checkInvariants(root);
2959	>	return null;
2960		}
2961
2962	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
2963	<	lock();
2962	>	/**
2963	>	* Removes the given node, that must be present before this
2964	>	* call.  This is messier than typical red-black deletion code
2965	>	* because we cannot swap the contents of an interior node
2966	>	* with a leaf successor that is pinned by "next" pointers
2967	>	* that are accessible independently of lock. So instead we
2968	>	* swap the tree linkages.
2969	>	*
2970	>	* @return true if now too small, so should be untreeified
2971	>	*/
2972	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2973	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2974	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2975	>	TreeNode<K,V> r, rl;
2976	>	if (pred == null)
2977	>	first = next;
2978	>	else
2979	>	pred.next = next;
2980	>	if (next != null)
2981	>	next.prev = pred;
2982	>	if (first == null) {
2983	>	root = null;
2984	>	return true;
2985	>	}
2986	>	if ((r = root) == null || r.right == null || // too small
2987	>	(rl = r.left) == null || rl.left == null)
2988	>	return true;
2989	>	lockRoot();
2990		try {
2991	<	int c = count;
2992	<	HashEntry[] tab = table;
2993	<	int index = hash & (tab.length - 1);
2994	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
2995	<
2996	<	for (HashEntry<K,V> e = first; e != null; e = (HashEntry<K,V>) e.next) {
2997	<	if (e.hash == hash && key.equals(e.key)) {
2998	<	V oldValue = e.value;
2999	<	if (!onlyIfAbsent)
3000	<	e.value = value;
3001	<	++modCount;
3002	<	count = c; // write-volatile
3003	<	return oldValue;
2991	>	TreeNode<K,V> replacement;
2992	>	TreeNode<K,V> pl = p.left;
2993	>	TreeNode<K,V> pr = p.right;
2994	>	if (pl != null && pr != null) {
2995	>	TreeNode<K,V> s = pr, sl;
2996	>	while ((sl = s.left) != null) // find successor
2997	>	s = sl;
2998	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2999	>	TreeNode<K,V> sr = s.right;
3000	>	TreeNode<K,V> pp = p.parent;
3001	>	if (s == pr) { // p was s's direct parent
3002	>	p.parent = s;
3003	>	s.right = p;
3004		}
3005	+	else {
3006	+	TreeNode<K,V> sp = s.parent;
3007	+	if ((p.parent = sp) != null) {
3008	+	if (s == sp.left)
3009	+	sp.left = p;
3010	+	else
3011	+	sp.right = p;
3012	+	}
3013	+	if ((s.right = pr) != null)
3014	+	pr.parent = s;
3015	+	}
3016	+	p.left = null;
3017	+	if ((p.right = sr) != null)
3018	+	sr.parent = p;
3019	+	if ((s.left = pl) != null)
3020	+	pl.parent = s;
3021	+	if ((s.parent = pp) == null)
3022	+	r = s;
3023	+	else if (p == pp.left)
3024	+	pp.left = s;
3025	+	else
3026	+	pp.right = s;
3027	+	if (sr != null)
3028	+	replacement = sr;
3029	+	else
3030	+	replacement = p;
3031		}
3032	+	else if (pl != null)
3033	+	replacement = pl;
3034	+	else if (pr != null)
3035	+	replacement = pr;
3036	+	else
3037	+	replacement = p;
3038	+	if (replacement != p) {
3039	+	TreeNode<K,V> pp = replacement.parent = p.parent;
3040	+	if (pp == null)
3041	+	r = replacement;
3042	+	else if (p == pp.left)
3043	+	pp.left = replacement;
3044	+	else
3045	+	pp.right = replacement;
3046	+	p.left = p.right = p.parent = null;
3047	+	}
3048	+
3049	+	root = (p.red) ? r : balanceDeletion(r, replacement);
3050
3051	<	tab[index] = new HashEntry<K,V>(hash, key, value, first);
3052	<	++modCount;
3053	<	++c;
3054	<	count = c; // write-volatile
3055	<	if (c > threshold)
3056	<	setTable(rehash(tab));
3057	<	return null;
3051	>	if (p == replacement) {  // detach pointers
3052	>	TreeNode<K,V> pp;
3053	>	if ((pp = p.parent) != null) {
3054	>	if (p == pp.left)
3055	>	pp.left = null;
3056	>	else if (p == pp.right)
3057	>	pp.right = null;
3058	>	p.parent = null;
3059	>	}
3060	>	}
3061		} finally {
3062	<	unlock();
3062	>	unlockRoot();
3063		}
3064	+	assert checkInvariants(root);
3065	+	return false;
3066		}
3067
3068	<	private HashEntry[] rehash(HashEntry[] oldTable) {
3069	<	int oldCapacity = oldTable.length;
3070	<	if (oldCapacity >= MAXIMUM_CAPACITY)
3071	<	return oldTable;
3072	<
3073	<	/*
3074	<	* Reclassify nodes in each list to new Map.  Because we are
3075	<	* using power-of-two expansion, the elements from each bin
3076	<	* must either stay at same index, or move with a power of two
3077	<	* offset. We eliminate unnecessary node creation by catching
3078	<	* cases where old nodes can be reused because their next
3079	<	* fields won't change. Statistically, at the default
3080	<	* threshhold, only about one-sixth of them need cloning when
3081	<	* a table doubles. The nodes they replace will be garbage
3082	<	* collectable as soon as they are no longer referenced by any
3083	<	* reader thread that may be in the midst of traversing table
3084	<	* right now.
3085	<	*/
3086	<
3087	<	HashEntry[] newTable = new HashEntry[oldCapacity << 1];
3088	<	int sizeMask = newTable.length - 1;
3089	<	for (int i = 0; i < oldCapacity ; i++) {
3090	<	// We need to guarantee that any existing reads of old Map can
3091	<	//  proceed. So we cannot yet null out each bin.
3092	<	HashEntry<K,V> e = (HashEntry<K,V>)oldTable[i];
3093	<
3094	<	if (e != null) {
3095	<	HashEntry<K,V> next = e.next;
3096	<	int idx = e.hash & sizeMask;
3097	<
3098	<	//  Single node on list
3099	<	if (next == null)
3100	<	newTable[idx] = e;
3068	>	/* ------------------------------------------------------------ */
3069	>	// Red-black tree methods, all adapted from CLR
3070	>
3071	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3072	>	TreeNode<K,V> p) {
3073	>	TreeNode<K,V> r, pp, rl;
3074	>	if (p != null && (r = p.right) != null) {
3075	>	if ((rl = p.right = r.left) != null)
3076	>	rl.parent = p;
3077	>	if ((pp = r.parent = p.parent) == null)
3078	>	(root = r).red = false;
3079	>	else if (pp.left == p)
3080	>	pp.left = r;
3081	>	else
3082	>	pp.right = r;
3083	>	r.left = p;
3084	>	p.parent = r;
3085	>	}
3086	>	return root;
3087	>	}
3088	>
3089	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3090	>	TreeNode<K,V> p) {
3091	>	TreeNode<K,V> l, pp, lr;
3092	>	if (p != null && (l = p.left) != null) {
3093	>	if ((lr = p.left = l.right) != null)
3094	>	lr.parent = p;
3095	>	if ((pp = l.parent = p.parent) == null)
3096	>	(root = l).red = false;
3097	>	else if (pp.right == p)
3098	>	pp.right = l;
3099	>	else
3100	>	pp.left = l;
3101	>	l.right = p;
3102	>	p.parent = l;
3103	>	}
3104	>	return root;
3105	>	}
3106
3107	+	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3108	+	TreeNode<K,V> x) {
3109	+	x.red = true;
3110	+	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3111	+	if ((xp = x.parent) == null) {
3112	+	x.red = false;
3113	+	return x;
3114	+	}
3115	+	else if (!xp.red || (xpp = xp.parent) == null)
3116	+	return root;
3117	+	if (xp == (xppl = xpp.left)) {
3118	+	if ((xppr = xpp.right) != null && xppr.red) {
3119	+	xppr.red = false;
3120	+	xp.red = false;
3121	+	xpp.red = true;
3122	+	x = xpp;
3123	+	}
3124		else {
3125	<	// Reuse trailing consecutive sequence at same slot
3126	<	HashEntry<K,V> lastRun = e;
3127	<	int lastIdx = idx;
3128	<	for (HashEntry<K,V> last = next;
3129	<	last != null;
3130	<	last = last.next) {
3131	<	int k = last.hash & sizeMask;
3132	<	if (k != lastIdx) {
3133	<	lastIdx = k;
363	<	lastRun = last;
3125	>	if (x == xp.right) {
3126	>	root = rotateLeft(root, x = xp);
3127	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3128	>	}
3129	>	if (xp != null) {
3130	>	xp.red = false;
3131	>	if (xpp != null) {
3132	>	xpp.red = true;
3133	>	root = rotateRight(root, xpp);
3134		}
3135		}
3136	<	newTable[lastIdx] = lastRun;
3136	>	}
3137	>	}
3138	>	else {
3139	>	if (xppl != null && xppl.red) {
3140	>	xppl.red = false;
3141	>	xp.red = false;
3142	>	xpp.red = true;
3143	>	x = xpp;
3144	>	}
3145	>	else {
3146	>	if (x == xp.left) {
3147	>	root = rotateRight(root, x = xp);
3148	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3149	>	}
3150	>	if (xp != null) {
3151	>	xp.red = false;
3152	>	if (xpp != null) {
3153	>	xpp.red = true;
3154	>	root = rotateLeft(root, xpp);
3155	>	}
3156	>	}
3157	>	}
3158	>	}
3159	>	}
3160	>	}
3161
3162	<	// Clone all remaining nodes
3163	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
3164	<	int k = p.hash & sizeMask;
3165	<	newTable[k] = new HashEntry<K,V>(p.hash,
3166	<	p.key,
3167	<	p.value,
3168	<	(HashEntry<K,V>) newTable[k]);
3162	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3163	>	TreeNode<K,V> x) {
3164	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3165	>	if (x == null || x == root)
3166	>	return root;
3167	>	else if ((xp = x.parent) == null) {
3168	>	x.red = false;
3169	>	return x;
3170	>	}
3171	>	else if (x.red) {
3172	>	x.red = false;
3173	>	return root;
3174	>	}
3175	>	else if ((xpl = xp.left) == x) {
3176	>	if ((xpr = xp.right) != null && xpr.red) {
3177	>	xpr.red = false;
3178	>	xp.red = true;
3179	>	root = rotateLeft(root, xp);
3180	>	xpr = (xp = x.parent) == null ? null : xp.right;
3181	>	}
3182	>	if (xpr == null)
3183	>	x = xp;
3184	>	else {
3185	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3186	>	if ((sr == null || !sr.red) &&
3187	>	(sl == null || !sl.red)) {
3188	>	xpr.red = true;
3189	>	x = xp;
3190	>	}
3191	>	else {
3192	>	if (sr == null || !sr.red) {
3193	>	if (sl != null)
3194	>	sl.red = false;
3195	>	xpr.red = true;
3196	>	root = rotateRight(root, xpr);
3197	>	xpr = (xp = x.parent) == null ?
3198	>	null : xp.right;
3199	>	}
3200	>	if (xpr != null) {
3201	>	xpr.red = (xp == null) ? false : xp.red;
3202	>	if ((sr = xpr.right) != null)
3203	>	sr.red = false;
3204	>	}
3205	>	if (xp != null) {
3206	>	xp.red = false;
3207	>	root = rotateLeft(root, xp);
3208	>	}
3209	>	x = root;
3210	>	}
3211	>	}
3212	>	}
3213	>	else { // symmetric
3214	>	if (xpl != null && xpl.red) {
3215	>	xpl.red = false;
3216	>	xp.red = true;
3217	>	root = rotateRight(root, xp);
3218	>	xpl = (xp = x.parent) == null ? null : xp.left;
3219	>	}
3220	>	if (xpl == null)
3221	>	x = xp;
3222	>	else {
3223	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3224	>	if ((sl == null || !sl.red) &&
3225	>	(sr == null || !sr.red)) {
3226	>	xpl.red = true;
3227	>	x = xp;
3228	>	}
3229	>	else {
3230	>	if (sl == null || !sl.red) {
3231	>	if (sr != null)
3232	>	sr.red = false;
3233	>	xpl.red = true;
3234	>	root = rotateLeft(root, xpl);
3235	>	xpl = (xp = x.parent) == null ?
3236	>	null : xp.left;
3237	>	}
3238	>	if (xpl != null) {
3239	>	xpl.red = (xp == null) ? false : xp.red;
3240	>	if ((sl = xpl.left) != null)
3241	>	sl.red = false;
3242	>	}
3243	>	if (xp != null) {
3244	>	xp.red = false;
3245	>	root = rotateRight(root, xp);
3246	>	}
3247	>	x = root;
3248		}
3249		}
3250		}
3251		}
379	–	return newTable;
3252		}
3253
3254		/**
3255	<	* Remove; match on key only if value null, else match both.
3255	>	* Checks invariants recursively for the tree of Nodes rooted at t.
3256		*/
3257	<	V remove(Object key, int hash, Object value) {
3258	<	lock();
3257	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3258	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3259	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3260	>	if (tb != null && tb.next != t)
3261	>	return false;
3262	>	if (tn != null && tn.prev != t)
3263	>	return false;
3264	>	if (tp != null && t != tp.left && t != tp.right)
3265	>	return false;
3266	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3267	>	return false;
3268	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3269	>	return false;
3270	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3271	>	return false;
3272	>	if (tl != null && !checkInvariants(tl))
3273	>	return false;
3274	>	if (tr != null && !checkInvariants(tr))
3275	>	return false;
3276	>	return true;
3277	>	}
3278	>
3279	>	private static final Unsafe U = Unsafe.getUnsafe();
3280	>	private static final long LOCKSTATE;
3281	>	static {
3282		try {
3283	<	int c = count;
3284	<	HashEntry[] tab = table;
3285	<	int index = hash & (tab.length - 1);
3286	<	HashEntry<K,V> first = (HashEntry<K,V>)tab[index];
3283	>	LOCKSTATE = U.objectFieldOffset
3284	>	(TreeBin.class.getDeclaredField("lockState"));
3285	>	} catch (ReflectiveOperationException e) {
3286	>	throw new Error(e);
3287	>	}
3288	>	}
3289	>	}
3290
3291	<	HashEntry<K,V> e = first;
394	<	for (;;) {
395	<	if (e == null)
396	<	return null;
397	<	if (e.hash == hash && key.equals(e.key))
398	<	break;
399	<	e = e.next;
400	<	}
3291	>	/* ----------------Table Traversal -------------- */
3292
3293	<	V oldValue = e.value;
3294	<	if (value != null && !value.equals(oldValue))
3295	<	return null;
3293	>	/**
3294	>	* Records the table, its length, and current traversal index for a
3295	>	* traverser that must process a region of a forwarded table before
3296	>	* proceeding with current table.
3297	>	*/
3298	>	static final class TableStack<K,V> {
3299	>	int length;
3300	>	int index;
3301	>	Node<K,V>[] tab;
3302	>	TableStack<K,V> next;
3303	>	}
3304
3305	<	// All entries following removed node can stay in list, but
3306	<	// all preceeding ones need to be cloned.
3307	<	HashEntry<K,V> newFirst = e.next;
3308	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
3309	<	newFirst = new HashEntry<K,V>(p.hash, p.key,
3310	<	p.value, newFirst);
3311	<	tab[index] = newFirst;
3312	<	++modCount;
3313	<	count = c-1; // write-volatile
3314	<	return oldValue;
3315	<	} finally {
3316	<	unlock();
3305	>	/**
3306	>	* Encapsulates traversal for methods such as containsValue; also
3307	>	* serves as a base class for other iterators and spliterators.
3308	>	*
3309	>	* Method advance visits once each still-valid node that was
3310	>	* reachable upon iterator construction. It might miss some that
3311	>	* were added to a bin after the bin was visited, which is OK wrt
3312	>	* consistency guarantees. Maintaining this property in the face
3313	>	* of possible ongoing resizes requires a fair amount of
3314	>	* bookkeeping state that is difficult to optimize away amidst
3315	>	* volatile accesses.  Even so, traversal maintains reasonable
3316	>	* throughput.
3317	>	*
3318	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3319	>	* However, if the table has been resized, then all future steps
3320	>	* must traverse both the bin at the current index as well as at
3321	>	* (index + baseSize); and so on for further resizings. To
3322	>	* paranoically cope with potential sharing by users of iterators
3323	>	* across threads, iteration terminates if a bounds checks fails
3324	>	* for a table read.
3325	>	*/
3326	>	static class Traverser<K,V> {
3327	>	Node<K,V>[] tab;        // current table; updated if resized
3328	>	Node<K,V> next;         // the next entry to use
3329	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3330	>	int index;              // index of bin to use next
3331	>	int baseIndex;          // current index of initial table
3332	>	int baseLimit;          // index bound for initial table
3333	>	final int baseSize;     // initial table size
3334	>
3335	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3336	>	this.tab = tab;
3337	>	this.baseSize = size;
3338	>	this.baseIndex = this.index = index;
3339	>	this.baseLimit = limit;
3340	>	this.next = null;
3341	>	}
3342	>
3343	>	/**
3344	>	* Advances if possible, returning next valid node, or null if none.
3345	>	*/
3346	>	final Node<K,V> advance() {
3347	>	Node<K,V> e;
3348	>	if ((e = next) != null)
3349	>	e = e.next;
3350	>	for (;;) {
3351	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3352	>	if (e != null)
3353	>	return next = e;
3354	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3355	>	(n = t.length) <= (i = index) || i < 0)
3356	>	return next = null;
3357	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3358	>	if (e instanceof ForwardingNode) {
3359	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3360	>	e = null;
3361	>	pushState(t, i, n);
3362	>	continue;
3363	>	}
3364	>	else if (e instanceof TreeBin)
3365	>	e = ((TreeBin<K,V>)e).first;
3366	>	else
3367	>	e = null;
3368	>	}
3369	>	if (stack != null)
3370	>	recoverState(n);
3371	>	else if ((index = i + baseSize) >= n)
3372	>	index = ++baseIndex; // visit upper slots if present
3373		}
3374		}
3375
3376	<	void clear() {
3377	<	lock();
3378	<	try {
3379	<	HashEntry[] tab = table;
3380	<	for (int i = 0; i < tab.length ; i++)
3381	<	tab[i] = null;
3382	<	++modCount;
3383	<	count = 0; // write-volatile
3384	<	} finally {
3385	<	unlock();
3376	>	/**
3377	>	* Saves traversal state upon encountering a forwarding node.
3378	>	*/
3379	>	private void pushState(Node<K,V>[] t, int i, int n) {
3380	>	TableStack<K,V> s = spare;  // reuse if possible
3381	>	if (s != null)
3382	>	spare = s.next;
3383	>	else
3384	>	s = new TableStack<K,V>();
3385	>	s.tab = t;
3386	>	s.length = n;
3387	>	s.index = i;
3388	>	s.next = stack;
3389	>	stack = s;
3390	>	}
3391	>
3392	>	/**
3393	>	* Possibly pops traversal state.
3394	>	*
3395	>	* @param n length of current table
3396	>	*/
3397	>	private void recoverState(int n) {
3398	>	TableStack<K,V> s; int len;
3399	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3400	>	n = len;
3401	>	index = s.index;
3402	>	tab = s.tab;
3403	>	s.tab = null;
3404	>	TableStack<K,V> next = s.next;
3405	>	s.next = spare; // save for reuse
3406	>	stack = next;
3407	>	spare = s;
3408		}
3409	+	if (s == null && (index += baseSize) >= n)
3410	+	index = ++baseIndex;
3411		}
3412		}
3413
3414		/**
3415	<	* ConcurrentHashMap list entry.
3415	>	* Base of key, value, and entry Iterators. Adds fields to
3416	>	* Traverser to support iterator.remove.
3417		*/
3418	<	private static class HashEntry<K,V> implements Entry<K,V> {
3419	<	private final K key;
3420	<	private V value;
3421	<	private final int hash;
3422	<	private final HashEntry<K,V> next;
3418	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3419	>	final ConcurrentHashMap<K,V> map;
3420	>	Node<K,V> lastReturned;
3421	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3422	>	ConcurrentHashMap<K,V> map) {
3423	>	super(tab, size, index, limit);
3424	>	this.map = map;
3425	>	advance();
3426	>	}
3427
3428	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
3429	<	this.value = value;
3430	<	this.hash = hash;
3431	<	this.key = key;
3432	<	this.next = next;
3428	>	public final boolean hasNext() { return next != null; }
3429	>	public final boolean hasMoreElements() { return next != null; }
3430	>
3431	>	public final void remove() {
3432	>	Node<K,V> p;
3433	>	if ((p = lastReturned) == null)
3434	>	throw new IllegalStateException();
3435	>	lastReturned = null;
3436	>	map.replaceNode(p.key, null, null);
3437		}
3438	+	}
3439
3440	<	public K getKey() {
3441	<	return key;
3440	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3441	>	implements Iterator<K>, Enumeration<K> {
3442	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3443	>	ConcurrentHashMap<K,V> map) {
3444	>	super(tab, index, size, limit, map);
3445		}
3446
3447	<	public V getValue() {
3448	<	return value;
3447	>	public final K next() {
3448	>	Node<K,V> p;
3449	>	if ((p = next) == null)
3450	>	throw new NoSuchElementException();
3451	>	K k = p.key;
3452	>	lastReturned = p;
3453	>	advance();
3454	>	return k;
3455		}
3456
3457	<	public V setValue(V newValue) {
3458	<	// We aren't required to, and don't provide any
3459	<	// visibility barriers for setting value.
3460	<	if (newValue == null)
3461	<	throw new NullPointerException();
3462	<	V oldValue = this.value;
3463	<	this.value = newValue;
3464	<	return oldValue;
3457	>	public final K nextElement() { return next(); }
3458	>	}
3459	>
3460	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3461	>	implements Iterator<V>, Enumeration<V> {
3462	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3463	>	ConcurrentHashMap<K,V> map) {
3464	>	super(tab, index, size, limit, map);
3465		}
3466
3467	<	public boolean equals(Object o) {
3468	<	if (!(o instanceof Entry))
3469	<	return false;
3470	<	Entry<K,V> e = (Entry<K,V>)o;
3471	<	return (key.equals(e.getKey()) && value.equals(e.getValue()));
3467	>	public final V next() {
3468	>	Node<K,V> p;
3469	>	if ((p = next) == null)
3470	>	throw new NoSuchElementException();
3471	>	V v = p.val;
3472	>	lastReturned = p;
3473	>	advance();
3474	>	return v;
3475		}
3476
3477	<	public int hashCode() {
3478	<	return  key.hashCode() ^ value.hashCode();
3477	>	public final V nextElement() { return next(); }
3478	>	}
3479	>
3480	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3481	>	implements Iterator<Map.Entry<K,V>> {
3482	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3483	>	ConcurrentHashMap<K,V> map) {
3484	>	super(tab, index, size, limit, map);
3485		}
3486
3487	+	public final Map.Entry<K,V> next() {
3488	+	Node<K,V> p;
3489	+	if ((p = next) == null)
3490	+	throw new NoSuchElementException();
3491	+	K k = p.key;
3492	+	V v = p.val;
3493	+	lastReturned = p;
3494	+	advance();
3495	+	return new MapEntry<K,V>(k, v, map);
3496	+	}
3497	+	}
3498	+
3499	+	/**
3500	+	* Exported Entry for EntryIterator.
3501	+	*/
3502	+	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3503	+	final K key; // non-null
3504	+	V val;       // non-null
3505	+	final ConcurrentHashMap<K,V> map;
3506	+	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3507	+	this.key = key;
3508	+	this.val = val;
3509	+	this.map = map;
3510	+	}
3511	+	public K getKey()        { return key; }
3512	+	public V getValue()      { return val; }
3513	+	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3514		public String toString() {
3515	<	return key + "=" + value;
3515	>	return Helpers.mapEntryToString(key, val);
3516	>	}
3517	>
3518	>	public boolean equals(Object o) {
3519	>	Object k, v; Map.Entry<?,?> e;
3520	>	return ((o instanceof Map.Entry) &&
3521	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3522	>	(v = e.getValue()) != null &&
3523	>	(k == key || k.equals(key)) &&
3524	>	(v == val || v.equals(val)));
3525	>	}
3526	>
3527	>	/**
3528	>	* Sets our entry's value and writes through to the map. The
3529	>	* value to return is somewhat arbitrary here. Since we do not
3530	>	* necessarily track asynchronous changes, the most recent
3531	>	* "previous" value could be different from what we return (or
3532	>	* could even have been removed, in which case the put will
3533	>	* re-establish). We do not and cannot guarantee more.
3534	>	*/
3535	>	public V setValue(V value) {
3536	>	if (value == null) throw new NullPointerException();
3537	>	V v = val;
3538	>	val = value;
3539	>	map.put(key, value);
3540	>	return v;
3541		}
3542		}
3543
3544	+	static final class KeySpliterator<K,V> extends Traverser<K,V>
3545	+	implements Spliterator<K> {
3546	+	long est;               // size estimate
3547	+	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3548	+	long est) {
3549	+	super(tab, size, index, limit);
3550	+	this.est = est;
3551	+	}
3552	+
3553	+	public KeySpliterator<K,V> trySplit() {
3554	+	int i, f, h;
3555	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3556	+	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3557	+	f, est >>>= 1);
3558	+	}
3559	+
3560	+	public void forEachRemaining(Consumer<? super K> action) {
3561	+	if (action == null) throw new NullPointerException();
3562	+	for (Node<K,V> p; (p = advance()) != null;)
3563	+	action.accept(p.key);
3564	+	}
3565	+
3566	+	public boolean tryAdvance(Consumer<? super K> action) {
3567	+	if (action == null) throw new NullPointerException();
3568	+	Node<K,V> p;
3569	+	if ((p = advance()) == null)
3570	+	return false;
3571	+	action.accept(p.key);
3572	+	return true;
3573	+	}
3574
3575	<	/* ---------------- Public operations -------------- */
3575	>	public long estimateSize() { return est; }
3576
3577	<	/**
3578	<	* Constructs a new, empty map with the specified initial
3579	<	* capacity and the specified load factor.
3580	<	*
3581	<	* @param initialCapacity the initial capacity. The implementation
493	<	* performs internal sizing to accommodate this many elements.
494	<	* @param loadFactor  the load factor threshold, used to control resizing.
495	<	* @param concurrencyLevel the estimated number of concurrently
496	<	* updating threads. The implementation performs internal sizing
497	<	* to try to accommodate this many threads.
498	<	* @throws IllegalArgumentException if the initial capacity is
499	<	* negative or the load factor or concurrencyLevel are
500	<	* nonpositive.
501	<	*/
502	<	public ConcurrentHashMap(int initialCapacity,
503	<	float loadFactor, int concurrencyLevel) {
504	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
505	<	throw new IllegalArgumentException();
3577	>	public int characteristics() {
3578	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3579	>	Spliterator.NONNULL;
3580	>	}
3581	>	}
3582
3583	<	if (concurrencyLevel > MAX_SEGMENTS)
3584	<	concurrencyLevel = MAX_SEGMENTS;
3583	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3584	>	implements Spliterator<V> {
3585	>	long est;               // size estimate
3586	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3587	>	long est) {
3588	>	super(tab, size, index, limit);
3589	>	this.est = est;
3590	>	}
3591	>
3592	>	public ValueSpliterator<K,V> trySplit() {
3593	>	int i, f, h;
3594	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3595	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3596	>	f, est >>>= 1);
3597	>	}
3598	>
3599	>	public void forEachRemaining(Consumer<? super V> action) {
3600	>	if (action == null) throw new NullPointerException();
3601	>	for (Node<K,V> p; (p = advance()) != null;)
3602	>	action.accept(p.val);
3603	>	}
3604	>
3605	>	public boolean tryAdvance(Consumer<? super V> action) {
3606	>	if (action == null) throw new NullPointerException();
3607	>	Node<K,V> p;
3608	>	if ((p = advance()) == null)
3609	>	return false;
3610	>	action.accept(p.val);
3611	>	return true;
3612	>	}
3613
3614	<	// Find power-of-two sizes best matching arguments
3615	<	int sshift = 0;
3616	<	int ssize = 1;
3617	<	while (ssize < concurrencyLevel) {
514	<	++sshift;
515	<	ssize <<= 1;
3614	>	public long estimateSize() { return est; }
3615	>
3616	>	public int characteristics() {
3617	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3618		}
3619	<	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;
3619	>	}
3620
3621	<	for (int i = 0; i < this.segments.length; ++i)
3622	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
3621	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3622	>	implements Spliterator<Map.Entry<K,V>> {
3623	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3624	>	long est;               // size estimate
3625	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3626	>	long est, ConcurrentHashMap<K,V> map) {
3627	>	super(tab, size, index, limit);
3628	>	this.map = map;
3629	>	this.est = est;
3630	>	}
3631	>
3632	>	public EntrySpliterator<K,V> trySplit() {
3633	>	int i, f, h;
3634	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3635	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3636	>	f, est >>>= 1, map);
3637	>	}
3638	>
3639	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3640	>	if (action == null) throw new NullPointerException();
3641	>	for (Node<K,V> p; (p = advance()) != null; )
3642	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3643	>	}
3644	>
3645	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3646	>	if (action == null) throw new NullPointerException();
3647	>	Node<K,V> p;
3648	>	if ((p = advance()) == null)
3649	>	return false;
3650	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3651	>	return true;
3652	>	}
3653	>
3654	>	public long estimateSize() { return est; }
3655	>
3656	>	public int characteristics() {
3657	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3658	>	Spliterator.NONNULL;
3659	>	}
3660		}
3661
3662	+	// Parallel bulk operations
3663	+
3664		/**
3665	<	* Constructs a new, empty map with the specified initial
3666	<	* capacity,  and with default load factor and concurrencyLevel.
3665	>	* Computes initial batch value for bulk tasks. The returned value
3666	>	* is approximately exp2 of the number of times (minus one) to
3667	>	* split task by two before executing leaf action. This value is
3668	>	* faster to compute and more convenient to use as a guide to
3669	>	* splitting than is the depth, since it is used while dividing by
3670	>	* two anyway.
3671	>	*/
3672	>	final int batchFor(long b) {
3673	>	long n;
3674	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3675	>	return 0;
3676	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3677	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3678	>	}
3679	>
3680	>	/**
3681	>	* Performs the given action for each (key, value).
3682		*
3683	<	* @param initialCapacity The implementation performs internal
3684	<	* sizing to accommodate this many elements.
3685	<	* @throws IllegalArgumentException if the initial capacity of
3686	<	* elements is negative.
3683	>	* @param parallelismThreshold the (estimated) number of elements
3684	>	* needed for this operation to be executed in parallel
3685	>	* @param action the action
3686	>	* @since 1.8
3687		*/
3688	<	public ConcurrentHashMap(int initialCapacity) {
3689	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3688	>	public void forEach(long parallelismThreshold,
3689	>	BiConsumer<? super K,? super V> action) {
3690	>	if (action == null) throw new NullPointerException();
3691	>	new ForEachMappingTask<K,V>
3692	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3693	>	action).invoke();
3694		}
3695
3696		/**
3697	<	* Constructs a new, empty map with a default initial capacity,
3698	<	* load factor, and concurrencyLevel.
3697	>	* Performs the given action for each non-null transformation
3698	>	* of each (key, value).
3699	>	*
3700	>	* @param parallelismThreshold the (estimated) number of elements
3701	>	* needed for this operation to be executed in parallel
3702	>	* @param transformer a function returning the transformation
3703	>	* for an element, or null if there is no transformation (in
3704	>	* which case the action is not applied)
3705	>	* @param action the action
3706	>	* @param <U> the return type of the transformer
3707	>	* @since 1.8
3708		*/
3709	<	public ConcurrentHashMap() {
3710	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3709	>	public <U> void forEach(long parallelismThreshold,
3710	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3711	>	Consumer<? super U> action) {
3712	>	if (transformer == null || action == null)
3713	>	throw new NullPointerException();
3714	>	new ForEachTransformedMappingTask<K,V,U>
3715	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3716	>	transformer, action).invoke();
3717		}
3718
3719		/**
3720	<	* Constructs a new map with the same mappings as the given map.  The
3721	<	* map is created with a capacity of twice the number of mappings in
3722	<	* the given map or 11 (whichever is greater), and a default load factor.
3720	>	* Returns a non-null result from applying the given search
3721	>	* function on each (key, value), or null if none.  Upon
3722	>	* success, further element processing is suppressed and the
3723	>	* results of any other parallel invocations of the search
3724	>	* function are ignored.
3725	>	*
3726	>	* @param parallelismThreshold the (estimated) number of elements
3727	>	* needed for this operation to be executed in parallel
3728	>	* @param searchFunction a function returning a non-null
3729	>	* result on success, else null
3730	>	* @param <U> the return type of the search function
3731	>	* @return a non-null result from applying the given search
3732	>	* function on each (key, value), or null if none
3733	>	* @since 1.8
3734		*/
3735	<	public <A extends K, B extends V> ConcurrentHashMap(Map<A,B> t) {
3736	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
3737	<	11),
3738	<	DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3739	<	putAll(t);
3735	>	public <U> U search(long parallelismThreshold,
3736	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3737	>	if (searchFunction == null) throw new NullPointerException();
3738	>	return new SearchMappingsTask<K,V,U>
3739	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3740	>	searchFunction, new AtomicReference<U>()).invoke();
3741		}
3742
3743	<	// inherit Map javadoc
3744	<	public boolean isEmpty() {
3745	<	/*
3746	<	* We need to keep track of per-segment modCounts to avoid ABA
3747	<	* problems in which an element in one segment was added and
3748	<	* in another removed during traversal, in which case the
3749	<	* table was never actually empty at any point. Note the
3750	<	* similar use of modCounts in the size() and containsValue()
3751	<	* methods, which are the only other methods also susceptible
3752	<	* to ABA problems.
3753	<	*/
3754	<	int[] mc = new int[segments.length];
3755	<	int mcsum = 0;
3756	<	for (int i = 0; i < segments.length; ++i) {
3757	<	if (segments[i].count != 0)
3758	<	return false;
3759	<	else
3760	<	mcsum += mc[i] = segments[i].modCount;
3761	<	}
3762	<	// If mcsum happens to be zero, then we know we got a snapshot
3763	<	// before any modifications at all were made.  This is
3764	<	// probably common enough to bother tracking.
3765	<	if (mcsum != 0) {
3766	<	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;
3743	>	/**
3744	>	* Returns the result of accumulating the given transformation
3745	>	* of all (key, value) pairs using the given reducer to
3746	>	* combine values, or null if none.
3747	>	*
3748	>	* @param parallelismThreshold the (estimated) number of elements
3749	>	* needed for this operation to be executed in parallel
3750	>	* @param transformer a function returning the transformation
3751	>	* for an element, or null if there is no transformation (in
3752	>	* which case it is not combined)
3753	>	* @param reducer a commutative associative combining function
3754	>	* @param <U> the return type of the transformer
3755	>	* @return the result of accumulating the given transformation
3756	>	* of all (key, value) pairs
3757	>	* @since 1.8
3758	>	*/
3759	>	public <U> U reduce(long parallelismThreshold,
3760	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3761	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3762	>	if (transformer == null || reducer == null)
3763	>	throw new NullPointerException();
3764	>	return new MapReduceMappingsTask<K,V,U>
3765	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3766	>	null, transformer, reducer).invoke();
3767		}
3768
3769	<	// inherit Map javadoc
3770	<	public int size() {
3771	<	int[] mc = new int[segments.length];
3772	<	for (;;) {
3773	<	long sum = 0;
3774	<	int mcsum = 0;
3775	<	for (int i = 0; i < segments.length; ++i) {
3776	<	sum += segments[i].count;
3777	<	mcsum += mc[i] = segments[i].modCount;
3778	<	}
3779	<	int check = 0;
3780	<	if (mcsum != 0) {
3781	<	for (int i = 0; i < segments.length; ++i) {
3782	<	check += segments[i].count;
3783	<	if (mc[i] != segments[i].modCount) {
3784	<	check = -1; // force retry
3785	<	break;
3786	<	}
3787	<	}
3788	<	}
3789	<	if (check == sum) {
3790	<	if (sum > Integer.MAX_VALUE)
3791	<	return Integer.MAX_VALUE;
3792	<	else
623	<	return (int)sum;
624	<	}
625	<	}
3769	>	/**
3770	>	* Returns the result of accumulating the given transformation
3771	>	* of all (key, value) pairs using the given reducer to
3772	>	* combine values, and the given basis as an identity value.
3773	>	*
3774	>	* @param parallelismThreshold the (estimated) number of elements
3775	>	* needed for this operation to be executed in parallel
3776	>	* @param transformer a function returning the transformation
3777	>	* for an element
3778	>	* @param basis the identity (initial default value) for the reduction
3779	>	* @param reducer a commutative associative combining function
3780	>	* @return the result of accumulating the given transformation
3781	>	* of all (key, value) pairs
3782	>	* @since 1.8
3783	>	*/
3784	>	public double reduceToDouble(long parallelismThreshold,
3785	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3786	>	double basis,
3787	>	DoubleBinaryOperator reducer) {
3788	>	if (transformer == null || reducer == null)
3789	>	throw new NullPointerException();
3790	>	return new MapReduceMappingsToDoubleTask<K,V>
3791	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3792	>	null, transformer, basis, reducer).invoke();
3793		}
3794
3795	+	/**
3796	+	* Returns the result of accumulating the given transformation
3797	+	* of all (key, value) pairs using the given reducer to
3798	+	* combine values, and the given basis as an identity value.
3799	+	*
3800	+	* @param parallelismThreshold the (estimated) number of elements
3801	+	* needed for this operation to be executed in parallel
3802	+	* @param transformer a function returning the transformation
3803	+	* for an element
3804	+	* @param basis the identity (initial default value) for the reduction
3805	+	* @param reducer a commutative associative combining function
3806	+	* @return the result of accumulating the given transformation
3807	+	* of all (key, value) pairs
3808	+	* @since 1.8
3809	+	*/
3810	+	public long reduceToLong(long parallelismThreshold,
3811	+	ToLongBiFunction<? super K, ? super V> transformer,
3812	+	long basis,
3813	+	LongBinaryOperator reducer) {
3814	+	if (transformer == null || reducer == null)
3815	+	throw new NullPointerException();
3816	+	return new MapReduceMappingsToLongTask<K,V>
3817	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3818	+	null, transformer, basis, reducer).invoke();
3819	+	}
3820
3821		/**
3822	<	* Returns the value to which the specified key is mapped in this table.
3822	>	* Returns the result of accumulating the given transformation
3823	>	* of all (key, value) pairs using the given reducer to
3824	>	* combine values, and the given basis as an identity value.
3825		*
3826	<	* @param   key   a key in the table.
3827	<	* @return  the value to which the key is mapped in this table;
3828	<	*          <tt>null</tt> if the key is not mapped to any value in
3829	<	*          this table.
3830	<	* @throws  NullPointerException  if the key is
3831	<	*               <tt>null</tt>.
3826	>	* @param parallelismThreshold the (estimated) number of elements
3827	>	* needed for this operation to be executed in parallel
3828	>	* @param transformer a function returning the transformation
3829	>	* for an element
3830	>	* @param basis the identity (initial default value) for the reduction
3831	>	* @param reducer a commutative associative combining function
3832	>	* @return the result of accumulating the given transformation
3833	>	* of all (key, value) pairs
3834	>	* @since 1.8
3835		*/
3836	<	public V get(Object key) {
3837	<	int hash = hash(key); // throws NullPointerException if key null
3838	<	return segmentFor(hash).get((K) key, hash);
3836	>	public int reduceToInt(long parallelismThreshold,
3837	>	ToIntBiFunction<? super K, ? super V> transformer,
3838	>	int basis,
3839	>	IntBinaryOperator reducer) {
3840	>	if (transformer == null || reducer == null)
3841	>	throw new NullPointerException();
3842	>	return new MapReduceMappingsToIntTask<K,V>
3843	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3844	>	null, transformer, basis, reducer).invoke();
3845		}
3846
3847		/**
3848	<	* Tests if the specified object is a key in this table.
3848	>	* Performs the given action for each key.
3849		*
3850	<	* @param   key   possible key.
3851	<	* @return  <tt>true</tt> if and only if the specified object
3852	<	*          is a key in this table, as determined by the
3853	<	*          <tt>equals</tt> method; <tt>false</tt> otherwise.
651	<	* @throws  NullPointerException  if the key is
652	<	*               <tt>null</tt>.
3850	>	* @param parallelismThreshold the (estimated) number of elements
3851	>	* needed for this operation to be executed in parallel
3852	>	* @param action the action
3853	>	* @since 1.8
3854		*/
3855	<	public boolean containsKey(Object key) {
3856	<	int hash = hash(key); // throws NullPointerException if key null
3857	<	return segmentFor(hash).containsKey(key, hash);
3855	>	public void forEachKey(long parallelismThreshold,
3856	>	Consumer<? super K> action) {
3857	>	if (action == null) throw new NullPointerException();
3858	>	new ForEachKeyTask<K,V>
3859	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3860	>	action).invoke();
3861		}
3862
3863		/**
3864	<	* Returns <tt>true</tt> if this map maps one or more keys to the
3865	<	* specified value. Note: This method requires a full internal
662	<	* traversal of the hash table, and so is much slower than
663	<	* method <tt>containsKey</tt>.
3864	>	* Performs the given action for each non-null transformation
3865	>	* of each key.
3866		*
3867	<	* @param value value whose presence in this map is to be tested.
3868	<	* @return <tt>true</tt> if this map maps one or more keys to the
3869	<	* specified value.
3870	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3867	>	* @param parallelismThreshold the (estimated) number of elements
3868	>	* needed for this operation to be executed in parallel
3869	>	* @param transformer a function returning the transformation
3870	>	* for an element, or null if there is no transformation (in
3871	>	* which case the action is not applied)
3872	>	* @param action the action
3873	>	* @param <U> the return type of the transformer
3874	>	* @since 1.8
3875		*/
3876	<	public boolean containsValue(Object value) {
3877	<	if (value == null)
3876	>	public <U> void forEachKey(long parallelismThreshold,
3877	>	Function<? super K, ? extends U> transformer,
3878	>	Consumer<? super U> action) {
3879	>	if (transformer == null || action == null)
3880		throw new NullPointerException();
3881	+	new ForEachTransformedKeyTask<K,V,U>
3882	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3883	+	transformer, action).invoke();
3884	+	}
3885
3886	<	int[] mc = new int[segments.length];
3887	<	for (;;) {
3888	<	int sum = 0;
3889	<	int mcsum = 0;
3890	<	for (int i = 0; i < segments.length; ++i) {
3891	<	int c = segments[i].count;
3892	<	mcsum += mc[i] = segments[i].modCount;
3893	<	if (segments[i].containsValue(value))
3894	<	return true;
3895	<	}
3896	<	boolean cleanSweep = true;
3897	<	if (mcsum != 0) {
3898	<	for (int i = 0; i < segments.length; ++i) {
3899	<	int c = segments[i].count;
3900	<	if (mc[i] != segments[i].modCount) {
3901	<	cleanSweep = false;
3902	<	break;
3903	<	}
3904	<	}
3905	<	}
3906	<	if (cleanSweep)
3907	<	return false;
696	<	}
3886	>	/**
3887	>	* Returns a non-null result from applying the given search
3888	>	* function on each key, or null if none. Upon success,
3889	>	* further element processing is suppressed and the results of
3890	>	* any other parallel invocations of the search function are
3891	>	* ignored.
3892	>	*
3893	>	* @param parallelismThreshold the (estimated) number of elements
3894	>	* needed for this operation to be executed in parallel
3895	>	* @param searchFunction a function returning a non-null
3896	>	* result on success, else null
3897	>	* @param <U> the return type of the search function
3898	>	* @return a non-null result from applying the given search
3899	>	* function on each key, or null if none
3900	>	* @since 1.8
3901	>	*/
3902	>	public <U> U searchKeys(long parallelismThreshold,
3903	>	Function<? super K, ? extends U> searchFunction) {
3904	>	if (searchFunction == null) throw new NullPointerException();
3905	>	return new SearchKeysTask<K,V,U>
3906	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3907	>	searchFunction, new AtomicReference<U>()).invoke();
3908		}
3909
3910		/**
3911	<	* Legacy method testing if some key maps into the specified value
3912	<	* in this table.  This method is identical in functionality to
3913	<	* {@link #containsValue}, and  exists solely to ensure
3914	<	* full compatibility with class {@link java.util.Hashtable},
3915	<	* which supported this method prior to introduction of the
3916	<	* Java Collections framework.
3911	>	* Returns the result of accumulating all keys using the given
3912	>	* reducer to combine values, or null if none.
3913	>	*
3914	>	* @param parallelismThreshold the (estimated) number of elements
3915	>	* needed for this operation to be executed in parallel
3916	>	* @param reducer a commutative associative combining function
3917	>	* @return the result of accumulating all keys using the given
3918	>	* reducer to combine values, or null if none
3919	>	* @since 1.8
3920	>	*/
3921	>	public K reduceKeys(long parallelismThreshold,
3922	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3923	>	if (reducer == null) throw new NullPointerException();
3924	>	return new ReduceKeysTask<K,V>
3925	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3926	>	null, reducer).invoke();
3927	>	}
3928
3929	<	* @param      value   a value to search for.
3930	<	* @return     <tt>true</tt> if and only if some key maps to the
3931	<	*             <tt>value</tt> argument in this table as
3932	<	*             determined by the <tt>equals</tt> method;
3933	<	*             <tt>false</tt> otherwise.
3934	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3929	>	/**
3930	>	* Returns the result of accumulating the given transformation
3931	>	* of all keys using the given reducer to combine values, or
3932	>	* null if none.
3933	>	*
3934	>	* @param parallelismThreshold the (estimated) number of elements
3935	>	* needed for this operation to be executed in parallel
3936	>	* @param transformer a function returning the transformation
3937	>	* for an element, or null if there is no transformation (in
3938	>	* which case it is not combined)
3939	>	* @param reducer a commutative associative combining function
3940	>	* @param <U> the return type of the transformer
3941	>	* @return the result of accumulating the given transformation
3942	>	* of all keys
3943	>	* @since 1.8
3944		*/
3945	<	public boolean contains(Object value) {
3946	<	return containsValue(value);
3945	>	public <U> U reduceKeys(long parallelismThreshold,
3946	>	Function<? super K, ? extends U> transformer,
3947	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3948	>	if (transformer == null || reducer == null)
3949	>	throw new NullPointerException();
3950	>	return new MapReduceKeysTask<K,V,U>
3951	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3952	>	null, transformer, reducer).invoke();
3953		}
3954
3955		/**
3956	<	* Maps the specified <tt>key</tt> to the specified
3957	<	* <tt>value</tt> in this table. Neither the key nor the
3958	<	* value can be <tt>null</tt>. <p>
3956	>	* Returns the result of accumulating the given transformation
3957	>	* of all keys using the given reducer to combine values, and
3958	>	* the given basis as an identity value.
3959		*
3960	<	* The value can be retrieved by calling the <tt>get</tt> method
3961	<	* with a key that is equal to the original key.
3960	>	* @param parallelismThreshold the (estimated) number of elements
3961	>	* needed for this operation to be executed in parallel
3962	>	* @param transformer a function returning the transformation
3963	>	* for an element
3964	>	* @param basis the identity (initial default value) for the reduction
3965	>	* @param reducer a commutative associative combining function
3966	>	* @return the result of accumulating the given transformation
3967	>	* of all keys
3968	>	* @since 1.8
3969	>	*/
3970	>	public double reduceKeysToDouble(long parallelismThreshold,
3971	>	ToDoubleFunction<? super K> transformer,
3972	>	double basis,
3973	>	DoubleBinaryOperator reducer) {
3974	>	if (transformer == null || reducer == null)
3975	>	throw new NullPointerException();
3976	>	return new MapReduceKeysToDoubleTask<K,V>
3977	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3978	>	null, transformer, basis, reducer).invoke();
3979	>	}
3980	>
3981	>	/**
3982	>	* Returns the result of accumulating the given transformation
3983	>	* of all keys using the given reducer to combine values, and
3984	>	* the given basis as an identity value.
3985		*
3986	<	* @param      key     the table key.
3987	<	* @param      value   the value.
3988	<	* @return     the previous value of the specified key in this table,
3989	<	*             or <tt>null</tt> if it did not have one.
3990	<	* @throws  NullPointerException  if the key or value is
3991	<	*               <tt>null</tt>.
3986	>	* @param parallelismThreshold the (estimated) number of elements
3987	>	* needed for this operation to be executed in parallel
3988	>	* @param transformer a function returning the transformation
3989	>	* for an element
3990	>	* @param basis the identity (initial default value) for the reduction
3991	>	* @param reducer a commutative associative combining function
3992	>	* @return the result of accumulating the given transformation
3993	>	* of all keys
3994	>	* @since 1.8
3995		*/
3996	<	public V put(K key, V value) {
3997	<	if (value == null)
3996	>	public long reduceKeysToLong(long parallelismThreshold,
3997	>	ToLongFunction<? super K> transformer,
3998	>	long basis,
3999	>	LongBinaryOperator reducer) {
4000	>	if (transformer == null || reducer == null)
4001		throw new NullPointerException();
4002	<	int hash = hash(key);
4003	<	return segmentFor(hash).put(key, hash, value, false);
4002	>	return new MapReduceKeysToLongTask<K,V>
4003	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4004	>	null, transformer, basis, reducer).invoke();
4005		}
4006
4007		/**
4008	<	* If the specified key is not already associated
4009	<	* with a value, associate it with the given value.
4010	<	* 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>.
4008	>	* Returns the result of accumulating the given transformation
4009	>	* of all keys using the given reducer to combine values, and
4010	>	* the given basis as an identity value.
4011		*
4012	<	**/
4013	<	public V putIfAbsent(K key, V value) {
4014	<	if (value == null)
4012	>	* @param parallelismThreshold the (estimated) number of elements
4013	>	* needed for this operation to be executed in parallel
4014	>	* @param transformer a function returning the transformation
4015	>	* for an element
4016	>	* @param basis the identity (initial default value) for the reduction
4017	>	* @param reducer a commutative associative combining function
4018	>	* @return the result of accumulating the given transformation
4019	>	* of all keys
4020	>	* @since 1.8
4021	>	*/
4022	>	public int reduceKeysToInt(long parallelismThreshold,
4023	>	ToIntFunction<? super K> transformer,
4024	>	int basis,
4025	>	IntBinaryOperator reducer) {
4026	>	if (transformer == null || reducer == null)
4027		throw new NullPointerException();
4028	<	int hash = hash(key);
4029	<	return segmentFor(hash).put(key, hash, value, true);
4028	>	return new MapReduceKeysToIntTask<K,V>
4029	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4030	>	null, transformer, basis, reducer).invoke();
4031		}
4032
4033	+	/**
4034	+	* Performs the given action for each value.
4035	+	*
4036	+	* @param parallelismThreshold the (estimated) number of elements
4037	+	* needed for this operation to be executed in parallel
4038	+	* @param action the action
4039	+	* @since 1.8
4040	+	*/
4041	+	public void forEachValue(long parallelismThreshold,
4042	+	Consumer<? super V> action) {
4043	+	if (action == null)
4044	+	throw new NullPointerException();
4045	+	new ForEachValueTask<K,V>
4046	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4047	+	action).invoke();
4048	+	}
4049
4050		/**
4051	<	* Copies all of the mappings from the specified map to this one.
4051	>	* Performs the given action for each non-null transformation
4052	>	* of each value.
4053		*
4054	<	* These mappings replace any mappings that this map had for any of the
4055	<	* keys currently in the specified Map.
4054	>	* @param parallelismThreshold the (estimated) number of elements
4055	>	* needed for this operation to be executed in parallel
4056	>	* @param transformer a function returning the transformation
4057	>	* for an element, or null if there is no transformation (in
4058	>	* which case the action is not applied)
4059	>	* @param action the action
4060	>	* @param <U> the return type of the transformer
4061	>	* @since 1.8
4062	>	*/
4063	>	public <U> void forEachValue(long parallelismThreshold,
4064	>	Function<? super V, ? extends U> transformer,
4065	>	Consumer<? super U> action) {
4066	>	if (transformer == null || action == null)
4067	>	throw new NullPointerException();
4068	>	new ForEachTransformedValueTask<K,V,U>
4069	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4070	>	transformer, action).invoke();
4071	>	}
4072	>
4073	>	/**
4074	>	* Returns a non-null result from applying the given search
4075	>	* function on each value, or null if none.  Upon success,
4076	>	* further element processing is suppressed and the results of
4077	>	* any other parallel invocations of the search function are
4078	>	* ignored.
4079		*
4080	<	* @param t Mappings to be stored in this map.
4080	>	* @param parallelismThreshold the (estimated) number of elements
4081	>	* needed for this operation to be executed in parallel
4082	>	* @param searchFunction a function returning a non-null
4083	>	* result on success, else null
4084	>	* @param <U> the return type of the search function
4085	>	* @return a non-null result from applying the given search
4086	>	* function on each value, or null if none
4087	>	* @since 1.8
4088		*/
4089	<	public void putAll(Map<? extends K, ? extends V> t) {
4090	<	for (Iterator<Map.Entry<? extends K, ? extends V>> it = (Iterator<Map.Entry<? extends K, ? extends V>>) t.entrySet().iterator(); it.hasNext(); ) {
4091	<	Entry<? extends K, ? extends V> e = it.next();
4092	<	put(e.getKey(), e.getValue());
4093	<	}
4089	>	public <U> U searchValues(long parallelismThreshold,
4090	>	Function<? super V, ? extends U> searchFunction) {
4091	>	if (searchFunction == null) throw new NullPointerException();
4092	>	return new SearchValuesTask<K,V,U>
4093	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4094	>	searchFunction, new AtomicReference<U>()).invoke();
4095		}
4096
4097		/**
4098	<	* Removes the key (and its corresponding value) from this
4099	<	* table. This method does nothing if the key is not in the table.
4098	>	* Returns the result of accumulating all values using the
4099	>	* given reducer to combine values, or null if none.
4100		*
4101	<	* @param   key   the key that needs to be removed.
4102	<	* @return  the value to which the key had been mapped in this table,
4103	<	*          or <tt>null</tt> if the key did not have a mapping.
4104	<	* @throws  NullPointerException  if the key is
4105	<	*               <tt>null</tt>.
4101	>	* @param parallelismThreshold the (estimated) number of elements
4102	>	* needed for this operation to be executed in parallel
4103	>	* @param reducer a commutative associative combining function
4104	>	* @return the result of accumulating all values
4105	>	* @since 1.8
4106		*/
4107	<	public V remove(Object key) {
4108	<	int hash = hash(key);
4109	<	return segmentFor(hash).remove(key, hash, null);
4107	>	public V reduceValues(long parallelismThreshold,
4108	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4109	>	if (reducer == null) throw new NullPointerException();
4110	>	return new ReduceValuesTask<K,V>
4111	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4112	>	null, reducer).invoke();
4113		}
4114
4115		/**
4116	<	* Remove entry for key only if currently mapped to given value.
4117	<	* Acts as
4118	<	* <pre>
4119	<	*  if (map.get(key).equals(value)) {
4120	<	*     map.remove(key);
4121	<	*     return true;
4122	<	* } else return false;
4123	<	* </pre>
4124	<	* except that the action is performed atomically.
4125	<	* @param key key with which the specified value is associated.
4126	<	* @param value value associated with the specified key.
4127	<	* @return true if the value was removed
4128	<	* @throws NullPointerException if the specified key is
4129	<	*            <tt>null</tt>.
4116	>	* Returns the result of accumulating the given transformation
4117	>	* of all values using the given reducer to combine values, or
4118	>	* null if none.
4119	>	*
4120	>	* @param parallelismThreshold the (estimated) number of elements
4121	>	* needed for this operation to be executed in parallel
4122	>	* @param transformer a function returning the transformation
4123	>	* for an element, or null if there is no transformation (in
4124	>	* which case it is not combined)
4125	>	* @param reducer a commutative associative combining function
4126	>	* @param <U> the return type of the transformer
4127	>	* @return the result of accumulating the given transformation
4128	>	* of all values
4129	>	* @since 1.8
4130		*/
4131	<	public boolean remove(Object key, Object value) {
4132	<	int hash = hash(key);
4133	<	return segmentFor(hash).remove(key, hash, value) != null;
4131	>	public <U> U reduceValues(long parallelismThreshold,
4132	>	Function<? super V, ? extends U> transformer,
4133	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4134	>	if (transformer == null || reducer == null)
4135	>	throw new NullPointerException();
4136	>	return new MapReduceValuesTask<K,V,U>
4137	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4138	>	null, transformer, reducer).invoke();
4139		}
4140
4141		/**
4142	<	* Removes all mappings from this map.
4142	>	* Returns the result of accumulating the given transformation
4143	>	* of all values using the given reducer to combine values,
4144	>	* and the given basis as an identity value.
4145	>	*
4146	>	* @param parallelismThreshold the (estimated) number of elements
4147	>	* needed for this operation to be executed in parallel
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 values
4154	>	* @since 1.8
4155		*/
4156	<	public void clear() {
4157	<	for (int i = 0; i < segments.length; ++i)
4158	<	segments[i].clear();
4156	>	public double reduceValuesToDouble(long parallelismThreshold,
4157	>	ToDoubleFunction<? super V> transformer,
4158	>	double basis,
4159	>	DoubleBinaryOperator reducer) {
4160	>	if (transformer == null || reducer == null)
4161	>	throw new NullPointerException();
4162	>	return new MapReduceValuesToDoubleTask<K,V>
4163	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4164	>	null, transformer, basis, reducer).invoke();
4165		}
4166
4167	+	/**
4168	+	* Returns the result of accumulating the given transformation
4169	+	* of all values using the given reducer to combine values,
4170	+	* and the given basis as an identity value.
4171	+	*
4172	+	* @param parallelismThreshold the (estimated) number of elements
4173	+	* needed for this operation to be executed in parallel
4174	+	* @param transformer a function returning the transformation
4175	+	* for an element
4176	+	* @param basis the identity (initial default value) for the reduction
4177	+	* @param reducer a commutative associative combining function
4178	+	* @return the result of accumulating the given transformation
4179	+	* of all values
4180	+	* @since 1.8
4181	+	*/
4182	+	public long reduceValuesToLong(long parallelismThreshold,
4183	+	ToLongFunction<? super V> transformer,
4184	+	long basis,
4185	+	LongBinaryOperator reducer) {
4186	+	if (transformer == null || reducer == null)
4187	+	throw new NullPointerException();
4188	+	return new MapReduceValuesToLongTask<K,V>
4189	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4190	+	null, transformer, basis, reducer).invoke();
4191	+	}
4192
4193		/**
4194	<	* Returns a shallow copy of this
4195	<	* <tt>ConcurrentHashMap</tt> instance: the keys and
4196	<	* values themselves are not cloned.
4194	>	* Returns the result of accumulating the given transformation
4195	>	* of all values using the given reducer to combine values,
4196	>	* and the given basis as an identity value.
4197		*
4198	<	* @return a shallow copy of this map.
4198	>	* @param parallelismThreshold the (estimated) number of elements
4199	>	* needed for this operation to be executed in parallel
4200	>	* @param transformer a function returning the transformation
4201	>	* for an element
4202	>	* @param basis the identity (initial default value) for the reduction
4203	>	* @param reducer a commutative associative combining function
4204	>	* @return the result of accumulating the given transformation
4205	>	* of all values
4206	>	* @since 1.8
4207		*/
4208	<	public Object clone() {
4209	<	// We cannot call super.clone, since it would share final
4210	<	// segments array, and there's no way to reassign finals.
4208	>	public int reduceValuesToInt(long parallelismThreshold,
4209	>	ToIntFunction<? super V> transformer,
4210	>	int basis,
4211	>	IntBinaryOperator reducer) {
4212	>	if (transformer == null || reducer == null)
4213	>	throw new NullPointerException();
4214	>	return new MapReduceValuesToIntTask<K,V>
4215	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4216	>	null, transformer, basis, reducer).invoke();
4217	>	}
4218
4219	<	float lf = segments[0].loadFactor;
4220	<	int segs = segments.length;
4221	<	int cap = (int)(size() / lf);
4222	<	if (cap < segs) cap = segs;
4223	<	ConcurrentHashMap<K,V> t = new ConcurrentHashMap<K,V>(cap, lf, segs);
4224	<	t.putAll(this);
4225	<	return t;
4219	>	/**
4220	>	* Performs the given action for each entry.
4221	>	*
4222	>	* @param parallelismThreshold the (estimated) number of elements
4223	>	* needed for this operation to be executed in parallel
4224	>	* @param action the action
4225	>	* @since 1.8
4226	>	*/
4227	>	public void forEachEntry(long parallelismThreshold,
4228	>	Consumer<? super Map.Entry<K,V>> action) {
4229	>	if (action == null) throw new NullPointerException();
4230	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4231	>	action).invoke();
4232		}
4233
4234		/**
4235	<	* Returns a set view of the keys contained in this map.  The set is
4236	<	* 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.
4235	>	* Performs the given action for each non-null transformation
4236	>	* of each entry.
4237		*
4238	<	* @return a set view of the keys contained in this map.
4238	>	* @param parallelismThreshold the (estimated) number of elements
4239	>	* needed for this operation to be executed in parallel
4240	>	* @param transformer a function returning the transformation
4241	>	* for an element, or null if there is no transformation (in
4242	>	* which case the action is not applied)
4243	>	* @param action the action
4244	>	* @param <U> the return type of the transformer
4245	>	* @since 1.8
4246		*/
4247	<	public Set<K> keySet() {
4248	<	Set<K> ks = keySet;
4249	<	return (ks != null) ? ks : (keySet = new KeySet());
4247	>	public <U> void forEachEntry(long parallelismThreshold,
4248	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4249	>	Consumer<? super U> action) {
4250	>	if (transformer == null || action == null)
4251	>	throw new NullPointerException();
4252	>	new ForEachTransformedEntryTask<K,V,U>
4253	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4254	>	transformer, action).invoke();
4255		}
4256
4257	+	/**
4258	+	* Returns a non-null result from applying the given search
4259	+	* function on each entry, or null if none.  Upon success,
4260	+	* further element processing is suppressed and the results of
4261	+	* any other parallel invocations of the search function are
4262	+	* ignored.
4263	+	*
4264	+	* @param parallelismThreshold the (estimated) number of elements
4265	+	* needed for this operation to be executed in parallel
4266	+	* @param searchFunction a function returning a non-null
4267	+	* result on success, else null
4268	+	* @param <U> the return type of the search function
4269	+	* @return a non-null result from applying the given search
4270	+	* function on each entry, or null if none
4271	+	* @since 1.8
4272	+	*/
4273	+	public <U> U searchEntries(long parallelismThreshold,
4274	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4275	+	if (searchFunction == null) throw new NullPointerException();
4276	+	return new SearchEntriesTask<K,V,U>
4277	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4278	+	searchFunction, new AtomicReference<U>()).invoke();
4279	+	}
4280
4281		/**
4282	<	* Returns a collection view of the values contained in this map.  The
4283	<	* collection is backed by the map, so changes to the map are reflected in
880	<	* the collection, and vice-versa.  The collection supports element
881	<	* removal, which removes the corresponding mapping from this map, via the
882	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
883	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
884	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
885	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
886	<	* will never throw {@link java.util.ConcurrentModificationException},
887	<	* 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.
4282	>	* Returns the result of accumulating all entries using the
4283	>	* given reducer to combine values, or null if none.
4284		*
4285	<	* @return a collection view of the values contained in this map.
4285	>	* @param parallelismThreshold the (estimated) number of elements
4286	>	* needed for this operation to be executed in parallel
4287	>	* @param reducer a commutative associative combining function
4288	>	* @return the result of accumulating all entries
4289	>	* @since 1.8
4290		*/
4291	<	public Collection<V> values() {
4292	<	Collection<V> vs = values;
4293	<	return (vs != null) ? vs : (values = new Values());
4291	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4292	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4293	>	if (reducer == null) throw new NullPointerException();
4294	>	return new ReduceEntriesTask<K,V>
4295	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4296	>	null, reducer).invoke();
4297		}
4298
4299	+	/**
4300	+	* Returns the result of accumulating the given transformation
4301	+	* of all entries using the given reducer to combine values,
4302	+	* or null if none.
4303	+	*
4304	+	* @param parallelismThreshold the (estimated) number of elements
4305	+	* needed for this operation to be executed in parallel
4306	+	* @param transformer a function returning the transformation
4307	+	* for an element, or null if there is no transformation (in
4308	+	* which case it is not combined)
4309	+	* @param reducer a commutative associative combining function
4310	+	* @param <U> the return type of the transformer
4311	+	* @return the result of accumulating the given transformation
4312	+	* of all entries
4313	+	* @since 1.8
4314	+	*/
4315	+	public <U> U reduceEntries(long parallelismThreshold,
4316	+	Function<Map.Entry<K,V>, ? extends U> transformer,
4317	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4318	+	if (transformer == null || reducer == null)
4319	+	throw new NullPointerException();
4320	+	return new MapReduceEntriesTask<K,V,U>
4321	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4322	+	null, transformer, reducer).invoke();
4323	+	}
4324
4325		/**
4326	<	* Returns a collection view of the mappings contained in this map.  Each
4327	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
4328	<	* collection is backed by the map, so changes to the map are reflected in
903	<	* the collection, and vice-versa.  The collection supports element
904	<	* removal, which removes the corresponding mapping from the map, via the
905	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
906	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
907	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
908	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
909	<	* will never throw {@link java.util.ConcurrentModificationException},
910	<	* and guarantees to traverse elements as they existed upon
911	<	* construction of the iterator, and may (but is not guaranteed to)
912	<	* reflect any modifications subsequent to construction.
4326	>	* Returns the result of accumulating the given transformation
4327	>	* of all entries using the given reducer to combine values,
4328	>	* and the given basis as an identity value.
4329		*
4330	<	* @return a collection view of the mappings contained in this map.
4330	>	* @param parallelismThreshold the (estimated) number of elements
4331	>	* needed for this operation to be executed in parallel
4332	>	* @param transformer a function returning the transformation
4333	>	* for an element
4334	>	* @param basis the identity (initial default value) for the reduction
4335	>	* @param reducer a commutative associative combining function
4336	>	* @return the result of accumulating the given transformation
4337	>	* of all entries
4338	>	* @since 1.8
4339		*/
4340	<	public Set<Map.Entry<K,V>> entrySet() {
4341	<	Set<Map.Entry<K,V>> es = entrySet;
4342	<	return (es != null) ? es : (entrySet = (Set<Map.Entry<K,V>>) (Set) new EntrySet());
4340	>	public double reduceEntriesToDouble(long parallelismThreshold,
4341	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4342	>	double basis,
4343	>	DoubleBinaryOperator reducer) {
4344	>	if (transformer == null || reducer == null)
4345	>	throw new NullPointerException();
4346	>	return new MapReduceEntriesToDoubleTask<K,V>
4347	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4348	>	null, transformer, basis, reducer).invoke();
4349		}
4350
4351	+	/**
4352	+	* Returns the result of accumulating the given transformation
4353	+	* of all entries using the given reducer to combine values,
4354	+	* and the given basis as an identity value.
4355	+	*
4356	+	* @param parallelismThreshold the (estimated) number of elements
4357	+	* needed for this operation to be executed in parallel
4358	+	* @param transformer a function returning the transformation
4359	+	* for an element
4360	+	* @param basis the identity (initial default value) for the reduction
4361	+	* @param reducer a commutative associative combining function
4362	+	* @return the result of accumulating the given transformation
4363	+	* of all entries
4364	+	* @since 1.8
4365	+	*/
4366	+	public long reduceEntriesToLong(long parallelismThreshold,
4367	+	ToLongFunction<Map.Entry<K,V>> transformer,
4368	+	long basis,
4369	+	LongBinaryOperator reducer) {
4370	+	if (transformer == null || reducer == null)
4371	+	throw new NullPointerException();
4372	+	return new MapReduceEntriesToLongTask<K,V>
4373	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4374	+	null, transformer, basis, reducer).invoke();
4375	+	}
4376
4377		/**
4378	<	* Returns an enumeration of the keys in this table.
4378	>	* Returns the result of accumulating the given transformation
4379	>	* of all entries using the given reducer to combine values,
4380	>	* and the given basis as an identity value.
4381		*
4382	<	* @return  an enumeration of the keys in this table.
4383	<	* @see     #keySet
4382	>	* @param parallelismThreshold the (estimated) number of elements
4383	>	* needed for this operation to be executed in parallel
4384	>	* @param transformer a function returning the transformation
4385	>	* for an element
4386	>	* @param basis the identity (initial default value) for the reduction
4387	>	* @param reducer a commutative associative combining function
4388	>	* @return the result of accumulating the given transformation
4389	>	* of all entries
4390	>	* @since 1.8
4391		*/
4392	<	public Enumeration<K> keys() {
4393	<	return new KeyIterator();
4392	>	public int reduceEntriesToInt(long parallelismThreshold,
4393	>	ToIntFunction<Map.Entry<K,V>> transformer,
4394	>	int basis,
4395	>	IntBinaryOperator reducer) {
4396	>	if (transformer == null || reducer == null)
4397	>	throw new NullPointerException();
4398	>	return new MapReduceEntriesToIntTask<K,V>
4399	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4400	>	null, transformer, basis, reducer).invoke();
4401		}
4402
4403	+
4404	+	/* ----------------Views -------------- */
4405	+
4406		/**
4407	<	* Returns an enumeration of the values in this table.
4408	<	* Use the Enumeration methods on the returned object to fetch the elements
4409	<	* sequentially.
4407	>	* Base class for views.
4408	>	*/
4409	>	abstract static class CollectionView<K,V,E>
4410	>	implements Collection<E>, java.io.Serializable {
4411	>	private static final long serialVersionUID = 7249069246763182397L;
4412	>	final ConcurrentHashMap<K,V> map;
4413	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4414	>
4415	>	/**
4416	>	* Returns the map backing this view.
4417	>	*
4418	>	* @return the map backing this view
4419	>	*/
4420	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4421	>
4422	>	/**
4423	>	* Removes all of the elements from this view, by removing all
4424	>	* the mappings from the map backing this view.
4425	>	*/
4426	>	public final void clear()      { map.clear(); }
4427	>	public final int size()        { return map.size(); }
4428	>	public final boolean isEmpty() { return map.isEmpty(); }
4429	>
4430	>	// implementations below rely on concrete classes supplying these
4431	>	// abstract methods
4432	>	/**
4433	>	* Returns an iterator over the elements in this collection.
4434	>	*
4435	>	* <p>The returned iterator is
4436	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4437	>	*
4438	>	* @return an iterator over the elements in this collection
4439	>	*/
4440	>	public abstract Iterator<E> iterator();
4441	>	public abstract boolean contains(Object o);
4442	>	public abstract boolean remove(Object o);
4443	>
4444	>	private static final String OOME_MSG = "Required array size too large";
4445	>
4446	>	public final Object[] toArray() {
4447	>	long sz = map.mappingCount();
4448	>	if (sz > MAX_ARRAY_SIZE)
4449	>	throw new OutOfMemoryError(OOME_MSG);
4450	>	int n = (int)sz;
4451	>	Object[] r = new Object[n];
4452	>	int i = 0;
4453	>	for (E e : this) {
4454	>	if (i == n) {
4455	>	if (n >= MAX_ARRAY_SIZE)
4456	>	throw new OutOfMemoryError(OOME_MSG);
4457	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4458	>	n = MAX_ARRAY_SIZE;
4459	>	else
4460	>	n += (n >>> 1) + 1;
4461	>	r = Arrays.copyOf(r, n);
4462	>	}
4463	>	r[i++] = e;
4464	>	}
4465	>	return (i == n) ? r : Arrays.copyOf(r, i);
4466	>	}
4467	>
4468	>	@SuppressWarnings("unchecked")
4469	>	public final <T> T[] toArray(T[] a) {
4470	>	long sz = map.mappingCount();
4471	>	if (sz > MAX_ARRAY_SIZE)
4472	>	throw new OutOfMemoryError(OOME_MSG);
4473	>	int m = (int)sz;
4474	>	T[] r = (a.length >= m) ? a :
4475	>	(T[])java.lang.reflect.Array
4476	>	.newInstance(a.getClass().getComponentType(), m);
4477	>	int n = r.length;
4478	>	int i = 0;
4479	>	for (E e : this) {
4480	>	if (i == n) {
4481	>	if (n >= MAX_ARRAY_SIZE)
4482	>	throw new OutOfMemoryError(OOME_MSG);
4483	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4484	>	n = MAX_ARRAY_SIZE;
4485	>	else
4486	>	n += (n >>> 1) + 1;
4487	>	r = Arrays.copyOf(r, n);
4488	>	}
4489	>	r[i++] = (T)e;
4490	>	}
4491	>	if (a == r && i < n) {
4492	>	r[i] = null; // null-terminate
4493	>	return r;
4494	>	}
4495	>	return (i == n) ? r : Arrays.copyOf(r, i);
4496	>	}
4497	>
4498	>	/**
4499	>	* Returns a string representation of this collection.
4500	>	* The string representation consists of the string representations
4501	>	* of the collection's elements in the order they are returned by
4502	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4503	>	* Adjacent elements are separated by the characters {@code ", "}
4504	>	* (comma and space).  Elements are converted to strings as by
4505	>	* {@link String#valueOf(Object)}.
4506	>	*
4507	>	* @return a string representation of this collection
4508	>	*/
4509	>	public final String toString() {
4510	>	StringBuilder sb = new StringBuilder();
4511	>	sb.append('[');
4512	>	Iterator<E> it = iterator();
4513	>	if (it.hasNext()) {
4514	>	for (;;) {
4515	>	Object e = it.next();
4516	>	sb.append(e == this ? "(this Collection)" : e);
4517	>	if (!it.hasNext())
4518	>	break;
4519	>	sb.append(',').append(' ');
4520	>	}
4521	>	}
4522	>	return sb.append(']').toString();
4523	>	}
4524	>
4525	>	public final boolean containsAll(Collection<?> c) {
4526	>	if (c != this) {
4527	>	for (Object e : c) {
4528	>	if (e == null || !contains(e))
4529	>	return false;
4530	>	}
4531	>	}
4532	>	return true;
4533	>	}
4534	>
4535	>	public boolean removeAll(Collection<?> c) {
4536	>	if (c == null) throw new NullPointerException();
4537	>	boolean modified = false;
4538	>	// Use (c instanceof Set) as a hint that lookup in c is as
4539	>	// efficient as this view
4540	>	if (c instanceof Set<?> && c.size() > map.table.length) {
4541	>	for (Iterator<?> it = iterator(); it.hasNext(); ) {
4542	>	if (c.contains(it.next())) {
4543	>	it.remove();
4544	>	modified = true;
4545	>	}
4546	>	}
4547	>	} else {
4548	>	for (Object e : c)
4549	>	modified |= remove(e);
4550	>	}
4551	>	return modified;
4552	>	}
4553	>
4554	>	public final boolean retainAll(Collection<?> c) {
4555	>	if (c == null) throw new NullPointerException();
4556	>	boolean modified = false;
4557	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4558	>	if (!c.contains(it.next())) {
4559	>	it.remove();
4560	>	modified = true;
4561	>	}
4562	>	}
4563	>	return modified;
4564	>	}
4565	>
4566	>	}
4567	>
4568	>	/**
4569	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4570	>	* which additions may optionally be enabled by mapping to a
4571	>	* common value.  This class cannot be directly instantiated.
4572	>	* See {@link #keySet() keySet()},
4573	>	* {@link #keySet(Object) keySet(V)},
4574	>	* {@link #newKeySet() newKeySet()},
4575	>	* {@link #newKeySet(int) newKeySet(int)}.
4576		*
4577	<	* @return  an enumeration of the values in this table.
938	<	* @see     #values
4577	>	* @since 1.8
4578		*/
4579	<	public Enumeration<V> elements() {
4580	<	return new ValueIterator();
4579	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4580	>	implements Set<K>, java.io.Serializable {
4581	>	private static final long serialVersionUID = 7249069246763182397L;
4582	>	private final V value;
4583	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4584	>	super(map);
4585	>	this.value = value;
4586	>	}
4587	>
4588	>	/**
4589	>	* Returns the default mapped value for additions,
4590	>	* or {@code null} if additions are not supported.
4591	>	*
4592	>	* @return the default mapped value for additions, or {@code null}
4593	>	* if not supported
4594	>	*/
4595	>	public V getMappedValue() { return value; }
4596	>
4597	>	/**
4598	>	* {@inheritDoc}
4599	>	* @throws NullPointerException if the specified key is null
4600	>	*/
4601	>	public boolean contains(Object o) { return map.containsKey(o); }
4602	>
4603	>	/**
4604	>	* Removes the key from this map view, by removing the key (and its
4605	>	* corresponding value) from the backing map.  This method does
4606	>	* nothing if the key is not in the map.
4607	>	*
4608	>	* @param  o the key to be removed from the backing map
4609	>	* @return {@code true} if the backing map contained the specified key
4610	>	* @throws NullPointerException if the specified key is null
4611	>	*/
4612	>	public boolean remove(Object o) { return map.remove(o) != null; }
4613	>
4614	>	/**
4615	>	* @return an iterator over the keys of the backing map
4616	>	*/
4617	>	public Iterator<K> iterator() {
4618	>	Node<K,V>[] t;
4619	>	ConcurrentHashMap<K,V> m = map;
4620	>	int f = (t = m.table) == null ? 0 : t.length;
4621	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4622	>	}
4623	>
4624	>	/**
4625	>	* Adds the specified key to this set view by mapping the key to
4626	>	* the default mapped value in the backing map, if defined.
4627	>	*
4628	>	* @param e key to be added
4629	>	* @return {@code true} if this set changed as a result of the call
4630	>	* @throws NullPointerException if the specified key is null
4631	>	* @throws UnsupportedOperationException if no default mapped value
4632	>	* for additions was provided
4633	>	*/
4634	>	public boolean add(K e) {
4635	>	V v;
4636	>	if ((v = value) == null)
4637	>	throw new UnsupportedOperationException();
4638	>	return map.putVal(e, v, true) == null;
4639	>	}
4640	>
4641	>	/**
4642	>	* Adds all of the elements in the specified collection to this set,
4643	>	* as if by calling {@link #add} on each one.
4644	>	*
4645	>	* @param c the elements to be inserted into this set
4646	>	* @return {@code true} if this set changed as a result of the call
4647	>	* @throws NullPointerException if the collection or any of its
4648	>	* elements are {@code null}
4649	>	* @throws UnsupportedOperationException if no default mapped value
4650	>	* for additions was provided
4651	>	*/
4652	>	public boolean addAll(Collection<? extends K> c) {
4653	>	boolean added = false;
4654	>	V v;
4655	>	if ((v = value) == null)
4656	>	throw new UnsupportedOperationException();
4657	>	for (K e : c) {
4658	>	if (map.putVal(e, v, true) == null)
4659	>	added = true;
4660	>	}
4661	>	return added;
4662	>	}
4663	>
4664	>	public int hashCode() {
4665	>	int h = 0;
4666	>	for (K e : this)
4667	>	h += e.hashCode();
4668	>	return h;
4669	>	}
4670	>
4671	>	public boolean equals(Object o) {
4672	>	Set<?> c;
4673	>	return ((o instanceof Set) &&
4674	>	((c = (Set<?>)o) == this ||
4675	>	(containsAll(c) && c.containsAll(this))));
4676	>	}
4677	>
4678	>	public Spliterator<K> spliterator() {
4679	>	Node<K,V>[] t;
4680	>	ConcurrentHashMap<K,V> m = map;
4681	>	long n = m.sumCount();
4682	>	int f = (t = m.table) == null ? 0 : t.length;
4683	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4684	>	}
4685	>
4686	>	public void forEach(Consumer<? super K> action) {
4687	>	if (action == null) throw new NullPointerException();
4688	>	Node<K,V>[] t;
4689	>	if ((t = map.table) != null) {
4690	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4691	>	for (Node<K,V> p; (p = it.advance()) != null; )
4692	>	action.accept(p.key);
4693	>	}
4694	>	}
4695		}
4696
4697	<	/* ---------------- Iterator Support -------------- */
4697	>	/**
4698	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4699	>	* values, in which additions are disabled. This class cannot be
4700	>	* directly instantiated. See {@link #values()}.
4701	>	*/
4702	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4703	>	implements Collection<V>, java.io.Serializable {
4704	>	private static final long serialVersionUID = 2249069246763182397L;
4705	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4706	>	public final boolean contains(Object o) {
4707	>	return map.containsValue(o);
4708	>	}
4709
4710	<	private abstract class HashIterator {
4711	<	private int nextSegmentIndex;
4712	<	private int nextTableIndex;
4713	<	private HashEntry[] currentTable;
4714	<	private HashEntry<K, V> nextEntry;
4715	<	private HashEntry<K, V> lastReturned;
4710	>	public final boolean remove(Object o) {
4711	>	if (o != null) {
4712	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4713	>	if (o.equals(it.next())) {
4714	>	it.remove();
4715	>	return true;
4716	>	}
4717	>	}
4718	>	}
4719	>	return false;
4720	>	}
4721
4722	<	private HashIterator() {
4723	<	nextSegmentIndex = segments.length - 1;
4724	<	nextTableIndex = -1;
4725	<	advance();
4722	>	public final Iterator<V> iterator() {
4723	>	ConcurrentHashMap<K,V> m = map;
4724	>	Node<K,V>[] t;
4725	>	int f = (t = m.table) == null ? 0 : t.length;
4726	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4727	>	}
4728	>
4729	>	public final boolean add(V e) {
4730	>	throw new UnsupportedOperationException();
4731	>	}
4732	>	public final boolean addAll(Collection<? extends V> c) {
4733	>	throw new UnsupportedOperationException();
4734	>	}
4735	>
4736	>	@Override public boolean removeAll(Collection<?> c) {
4737	>	if (c == null) throw new NullPointerException();
4738	>	boolean modified = false;
4739	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4740	>	if (c.contains(it.next())) {
4741	>	it.remove();
4742	>	modified = true;
4743	>	}
4744	>	}
4745	>	return modified;
4746		}
4747
4748	<	public boolean hasMoreElements() { return hasNext(); }
4748	>	public boolean removeIf(Predicate<? super V> filter) {
4749	>	return map.removeValueIf(filter);
4750	>	}
4751
4752	<	private void advance() {
4753	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
4754	<	return;
4752	>	public Spliterator<V> spliterator() {
4753	>	Node<K,V>[] t;
4754	>	ConcurrentHashMap<K,V> m = map;
4755	>	long n = m.sumCount();
4756	>	int f = (t = m.table) == null ? 0 : t.length;
4757	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4758	>	}
4759
4760	<	while (nextTableIndex >= 0) {
4761	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[nextTableIndex--]) != null)
4762	<	return;
4760	>	public void forEach(Consumer<? super V> action) {
4761	>	if (action == null) throw new NullPointerException();
4762	>	Node<K,V>[] t;
4763	>	if ((t = map.table) != null) {
4764	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4765	>	for (Node<K,V> p; (p = it.advance()) != null; )
4766	>	action.accept(p.val);
4767		}
4768	+	}
4769	+	}
4770
4771	<	while (nextSegmentIndex >= 0) {
4772	<	Segment<K,V> seg = (Segment<K,V>)segments[nextSegmentIndex--];
4773	<	if (seg.count != 0) {
4774	<	currentTable = seg.table;
4775	<	for (int j = currentTable.length - 1; j >= 0; --j) {
4776	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[j]) != null) {
4777	<	nextTableIndex = j - 1;
4778	<	return;
4779	<	}
4771	>	/**
4772	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4773	>	* entries.  This class cannot be directly instantiated. See
4774	>	* {@link #entrySet()}.
4775	>	*/
4776	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4777	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4778	>	private static final long serialVersionUID = 2249069246763182397L;
4779	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4780	>
4781	>	public boolean contains(Object o) {
4782	>	Object k, v, r; Map.Entry<?,?> e;
4783	>	return ((o instanceof Map.Entry) &&
4784	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4785	>	(r = map.get(k)) != null &&
4786	>	(v = e.getValue()) != null &&
4787	>	(v == r || v.equals(r)));
4788	>	}
4789	>
4790	>	public boolean remove(Object o) {
4791	>	Object k, v; Map.Entry<?,?> e;
4792	>	return ((o instanceof Map.Entry) &&
4793	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4794	>	(v = e.getValue()) != null &&
4795	>	map.remove(k, v));
4796	>	}
4797	>
4798	>	/**
4799	>	* @return an iterator over the entries of the backing map
4800	>	*/
4801	>	public Iterator<Map.Entry<K,V>> iterator() {
4802	>	ConcurrentHashMap<K,V> m = map;
4803	>	Node<K,V>[] t;
4804	>	int f = (t = m.table) == null ? 0 : t.length;
4805	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4806	>	}
4807	>
4808	>	public boolean add(Entry<K,V> e) {
4809	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4810	>	}
4811	>
4812	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4813	>	boolean added = false;
4814	>	for (Entry<K,V> e : c) {
4815	>	if (add(e))
4816	>	added = true;
4817	>	}
4818	>	return added;
4819	>	}
4820	>
4821	>	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4822	>	return map.removeEntryIf(filter);
4823	>	}
4824	>
4825	>	public final int hashCode() {
4826	>	int h = 0;
4827	>	Node<K,V>[] t;
4828	>	if ((t = map.table) != null) {
4829	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4830	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4831	>	h += p.hashCode();
4832	>	}
4833	>	}
4834	>	return h;
4835	>	}
4836	>
4837	>	public final boolean equals(Object o) {
4838	>	Set<?> c;
4839	>	return ((o instanceof Set) &&
4840	>	((c = (Set<?>)o) == this ||
4841	>	(containsAll(c) && c.containsAll(this))));
4842	>	}
4843	>
4844	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4845	>	Node<K,V>[] t;
4846	>	ConcurrentHashMap<K,V> m = map;
4847	>	long n = m.sumCount();
4848	>	int f = (t = m.table) == null ? 0 : t.length;
4849	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4850	>	}
4851	>
4852	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4853	>	if (action == null) throw new NullPointerException();
4854	>	Node<K,V>[] t;
4855	>	if ((t = map.table) != null) {
4856	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4857	>	for (Node<K,V> p; (p = it.advance()) != null; )
4858	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4859	>	}
4860	>	}
4861	>
4862	>	}
4863	>
4864	>	// -------------------------------------------------------
4865	>
4866	>	/**
4867	>	* Base class for bulk tasks. Repeats some fields and code from
4868	>	* class Traverser, because we need to subclass CountedCompleter.
4869	>	*/
4870	>	@SuppressWarnings("serial")
4871	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4872	>	Node<K,V>[] tab;        // same as Traverser
4873	>	Node<K,V> next;
4874	>	TableStack<K,V> stack, spare;
4875	>	int index;
4876	>	int baseIndex;
4877	>	int baseLimit;
4878	>	final int baseSize;
4879	>	int batch;              // split control
4880	>
4881	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4882	>	super(par);
4883	>	this.batch = b;
4884	>	this.index = this.baseIndex = i;
4885	>	if ((this.tab = t) == null)
4886	>	this.baseSize = this.baseLimit = 0;
4887	>	else if (par == null)
4888	>	this.baseSize = this.baseLimit = t.length;
4889	>	else {
4890	>	this.baseLimit = f;
4891	>	this.baseSize = par.baseSize;
4892	>	}
4893	>	}
4894	>
4895	>	/**
4896	>	* Same as Traverser version.
4897	>	*/
4898	>	final Node<K,V> advance() {
4899	>	Node<K,V> e;
4900	>	if ((e = next) != null)
4901	>	e = e.next;
4902	>	for (;;) {
4903	>	Node<K,V>[] t; int i, n;
4904	>	if (e != null)
4905	>	return next = e;
4906	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4907	>	(n = t.length) <= (i = index) || i < 0)
4908	>	return next = null;
4909	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4910	>	if (e instanceof ForwardingNode) {
4911	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4912	>	e = null;
4913	>	pushState(t, i, n);
4914	>	continue;
4915		}
4916	+	else if (e instanceof TreeBin)
4917	+	e = ((TreeBin<K,V>)e).first;
4918	+	else
4919	+	e = null;
4920		}
4921	+	if (stack != null)
4922	+	recoverState(n);
4923	+	else if ((index = i + baseSize) >= n)
4924	+	index = ++baseIndex;
4925		}
4926		}
4927
4928	<	public boolean hasNext() { return nextEntry != null; }
4928	>	private void pushState(Node<K,V>[] t, int i, int n) {
4929	>	TableStack<K,V> s = spare;
4930	>	if (s != null)
4931	>	spare = s.next;
4932	>	else
4933	>	s = new TableStack<K,V>();
4934	>	s.tab = t;
4935	>	s.length = n;
4936	>	s.index = i;
4937	>	s.next = stack;
4938	>	stack = s;
4939	>	}
4940	>
4941	>	private void recoverState(int n) {
4942	>	TableStack<K,V> s; int len;
4943	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4944	>	n = len;
4945	>	index = s.index;
4946	>	tab = s.tab;
4947	>	s.tab = null;
4948	>	TableStack<K,V> next = s.next;
4949	>	s.next = spare; // save for reuse
4950	>	stack = next;
4951	>	spare = s;
4952	>	}
4953	>	if (s == null && (index += baseSize) >= n)
4954	>	index = ++baseIndex;
4955	>	}
4956	>	}
4957
4958	<	HashEntry<K,V> nextEntry() {
4959	<	if (nextEntry == null)
4960	<	throw new NoSuchElementException();
4961	<	lastReturned = nextEntry;
4962	<	advance();
4963	<	return lastReturned;
4958	>	/*
4959	>	* Task classes. Coded in a regular but ugly format/style to
4960	>	* simplify checks that each variant differs in the right way from
4961	>	* others. The null screenings exist because compilers cannot tell
4962	>	* that we've already null-checked task arguments, so we force
4963	>	* simplest hoisted bypass to help avoid convoluted traps.
4964	>	*/
4965	>	@SuppressWarnings("serial")
4966	>	static final class ForEachKeyTask<K,V>
4967	>	extends BulkTask<K,V,Void> {
4968	>	final Consumer<? super K> action;
4969	>	ForEachKeyTask
4970	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4971	>	Consumer<? super K> action) {
4972	>	super(p, b, i, f, t);
4973	>	this.action = action;
4974	>	}
4975	>	public final void compute() {
4976	>	final Consumer<? super K> action;
4977	>	if ((action = this.action) != null) {
4978	>	for (int i = baseIndex, f, h; batch > 0 &&
4979	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4980	>	addToPendingCount(1);
4981	>	new ForEachKeyTask<K,V>
4982	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4983	>	action).fork();
4984	>	}
4985	>	for (Node<K,V> p; (p = advance()) != null;)
4986	>	action.accept(p.key);
4987	>	propagateCompletion();
4988	>	}
4989		}
4990	+	}
4991
4992	<	public void remove() {
4993	<	if (lastReturned == null)
4994	<	throw new IllegalStateException();
4995	<	ConcurrentHashMap.this.remove(lastReturned.key);
4996	<	lastReturned = null;
4992	>	@SuppressWarnings("serial")
4993	>	static final class ForEachValueTask<K,V>
4994	>	extends BulkTask<K,V,Void> {
4995	>	final Consumer<? super V> action;
4996	>	ForEachValueTask
4997	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4998	>	Consumer<? super V> action) {
4999	>	super(p, b, i, f, t);
5000	>	this.action = action;
5001	>	}
5002	>	public final void compute() {
5003	>	final Consumer<? super V> action;
5004	>	if ((action = this.action) != null) {
5005	>	for (int i = baseIndex, f, h; batch > 0 &&
5006	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5007	>	addToPendingCount(1);
5008	>	new ForEachValueTask<K,V>
5009	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5010	>	action).fork();
5011	>	}
5012	>	for (Node<K,V> p; (p = advance()) != null;)
5013	>	action.accept(p.val);
5014	>	propagateCompletion();
5015	>	}
5016		}
5017		}
5018
5019	<	private class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
5020	<	public K next() { return super.nextEntry().key; }
5021	<	public K nextElement() { return super.nextEntry().key; }
5019	>	@SuppressWarnings("serial")
5020	>	static final class ForEachEntryTask<K,V>
5021	>	extends BulkTask<K,V,Void> {
5022	>	final Consumer<? super Entry<K,V>> action;
5023	>	ForEachEntryTask
5024	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5025	>	Consumer<? super Entry<K,V>> action) {
5026	>	super(p, b, i, f, t);
5027	>	this.action = action;
5028	>	}
5029	>	public final void compute() {
5030	>	final Consumer<? super Entry<K,V>> action;
5031	>	if ((action = this.action) != null) {
5032	>	for (int i = baseIndex, f, h; batch > 0 &&
5033	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5034	>	addToPendingCount(1);
5035	>	new ForEachEntryTask<K,V>
5036	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5037	>	action).fork();
5038	>	}
5039	>	for (Node<K,V> p; (p = advance()) != null; )
5040	>	action.accept(p);
5041	>	propagateCompletion();
5042	>	}
5043	>	}
5044		}
5045
5046	<	private class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
5047	<	public V next() { return super.nextEntry().value; }
5048	<	public V nextElement() { return super.nextEntry().value; }
5046	>	@SuppressWarnings("serial")
5047	>	static final class ForEachMappingTask<K,V>
5048	>	extends BulkTask<K,V,Void> {
5049	>	final BiConsumer<? super K, ? super V> action;
5050	>	ForEachMappingTask
5051	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5052	>	BiConsumer<? super K,? super V> action) {
5053	>	super(p, b, i, f, t);
5054	>	this.action = action;
5055	>	}
5056	>	public final void compute() {
5057	>	final BiConsumer<? super K, ? super V> action;
5058	>	if ((action = this.action) != null) {
5059	>	for (int i = baseIndex, f, h; batch > 0 &&
5060	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5061	>	addToPendingCount(1);
5062	>	new ForEachMappingTask<K,V>
5063	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5064	>	action).fork();
5065	>	}
5066	>	for (Node<K,V> p; (p = advance()) != null; )
5067	>	action.accept(p.key, p.val);
5068	>	propagateCompletion();
5069	>	}
5070	>	}
5071		}
5072
5073	<	private class EntryIterator extends HashIterator implements Iterator<Entry<K,V>> {
5074	<	public Map.Entry<K,V> next() { return super.nextEntry(); }
5073	>	@SuppressWarnings("serial")
5074	>	static final class ForEachTransformedKeyTask<K,V,U>
5075	>	extends BulkTask<K,V,Void> {
5076	>	final Function<? super K, ? extends U> transformer;
5077	>	final Consumer<? super U> action;
5078	>	ForEachTransformedKeyTask
5079	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5080	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5081	>	super(p, b, i, f, t);
5082	>	this.transformer = transformer; this.action = action;
5083	>	}
5084	>	public final void compute() {
5085	>	final Function<? super K, ? extends U> transformer;
5086	>	final Consumer<? super U> action;
5087	>	if ((transformer = this.transformer) != null &&
5088	>	(action = this.action) != null) {
5089	>	for (int i = baseIndex, f, h; batch > 0 &&
5090	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5091	>	addToPendingCount(1);
5092	>	new ForEachTransformedKeyTask<K,V,U>
5093	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5094	>	transformer, action).fork();
5095	>	}
5096	>	for (Node<K,V> p; (p = advance()) != null; ) {
5097	>	U u;
5098	>	if ((u = transformer.apply(p.key)) != null)
5099	>	action.accept(u);
5100	>	}
5101	>	propagateCompletion();
5102	>	}
5103	>	}
5104		}
5105
5106	<	private class KeySet extends AbstractSet<K> {
5107	<	public Iterator<K> iterator() {
5108	<	return new KeyIterator();
5106	>	@SuppressWarnings("serial")
5107	>	static final class ForEachTransformedValueTask<K,V,U>
5108	>	extends BulkTask<K,V,Void> {
5109	>	final Function<? super V, ? extends U> transformer;
5110	>	final Consumer<? super U> action;
5111	>	ForEachTransformedValueTask
5112	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5113	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5114	>	super(p, b, i, f, t);
5115	>	this.transformer = transformer; this.action = action;
5116	>	}
5117	>	public final void compute() {
5118	>	final Function<? super V, ? extends U> transformer;
5119	>	final Consumer<? super U> action;
5120	>	if ((transformer = this.transformer) != null &&
5121	>	(action = this.action) != null) {
5122	>	for (int i = baseIndex, f, h; batch > 0 &&
5123	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5124	>	addToPendingCount(1);
5125	>	new ForEachTransformedValueTask<K,V,U>
5126	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5127	>	transformer, action).fork();
5128	>	}
5129	>	for (Node<K,V> p; (p = advance()) != null; ) {
5130	>	U u;
5131	>	if ((u = transformer.apply(p.val)) != null)
5132	>	action.accept(u);
5133	>	}
5134	>	propagateCompletion();
5135	>	}
5136		}
5137	<	public int size() {
5138	<	return ConcurrentHashMap.this.size();
5137	>	}
5138	>
5139	>	@SuppressWarnings("serial")
5140	>	static final class ForEachTransformedEntryTask<K,V,U>
5141	>	extends BulkTask<K,V,Void> {
5142	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5143	>	final Consumer<? super U> action;
5144	>	ForEachTransformedEntryTask
5145	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5146	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5147	>	super(p, b, i, f, t);
5148	>	this.transformer = transformer; this.action = action;
5149	>	}
5150	>	public final void compute() {
5151	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5152	>	final Consumer<? super U> action;
5153	>	if ((transformer = this.transformer) != null &&
5154	>	(action = this.action) != null) {
5155	>	for (int i = baseIndex, f, h; batch > 0 &&
5156	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5157	>	addToPendingCount(1);
5158	>	new ForEachTransformedEntryTask<K,V,U>
5159	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5160	>	transformer, action).fork();
5161	>	}
5162	>	for (Node<K,V> p; (p = advance()) != null; ) {
5163	>	U u;
5164	>	if ((u = transformer.apply(p)) != null)
5165	>	action.accept(u);
5166	>	}
5167	>	propagateCompletion();
5168	>	}
5169		}
5170	<	public boolean contains(Object o) {
5171	<	return ConcurrentHashMap.this.containsKey(o);
5170	>	}
5171	>
5172	>	@SuppressWarnings("serial")
5173	>	static final class ForEachTransformedMappingTask<K,V,U>
5174	>	extends BulkTask<K,V,Void> {
5175	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5176	>	final Consumer<? super U> action;
5177	>	ForEachTransformedMappingTask
5178	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5179	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5180	>	Consumer<? super U> action) {
5181	>	super(p, b, i, f, t);
5182	>	this.transformer = transformer; this.action = action;
5183	>	}
5184	>	public final void compute() {
5185	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5186	>	final Consumer<? super U> action;
5187	>	if ((transformer = this.transformer) != null &&
5188	>	(action = this.action) != null) {
5189	>	for (int i = baseIndex, f, h; batch > 0 &&
5190	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5191	>	addToPendingCount(1);
5192	>	new ForEachTransformedMappingTask<K,V,U>
5193	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5194	>	transformer, action).fork();
5195	>	}
5196	>	for (Node<K,V> p; (p = advance()) != null; ) {
5197	>	U u;
5198	>	if ((u = transformer.apply(p.key, p.val)) != null)
5199	>	action.accept(u);
5200	>	}
5201	>	propagateCompletion();
5202	>	}
5203		}
5204	<	public boolean remove(Object o) {
5205	<	return ConcurrentHashMap.this.remove(o) != null;
5204	>	}
5205	>
5206	>	@SuppressWarnings("serial")
5207	>	static final class SearchKeysTask<K,V,U>
5208	>	extends BulkTask<K,V,U> {
5209	>	final Function<? super K, ? extends U> searchFunction;
5210	>	final AtomicReference<U> result;
5211	>	SearchKeysTask
5212	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5213	>	Function<? super K, ? extends U> searchFunction,
5214	>	AtomicReference<U> result) {
5215	>	super(p, b, i, f, t);
5216	>	this.searchFunction = searchFunction; this.result = result;
5217	>	}
5218	>	public final U getRawResult() { return result.get(); }
5219	>	public final void compute() {
5220	>	final Function<? super K, ? extends U> searchFunction;
5221	>	final AtomicReference<U> result;
5222	>	if ((searchFunction = this.searchFunction) != null &&
5223	>	(result = this.result) != null) {
5224	>	for (int i = baseIndex, f, h; batch > 0 &&
5225	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5226	>	if (result.get() != null)
5227	>	return;
5228	>	addToPendingCount(1);
5229	>	new SearchKeysTask<K,V,U>
5230	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5231	>	searchFunction, result).fork();
5232	>	}
5233	>	while (result.get() == null) {
5234	>	U u;
5235	>	Node<K,V> p;
5236	>	if ((p = advance()) == null) {
5237	>	propagateCompletion();
5238	>	break;
5239	>	}
5240	>	if ((u = searchFunction.apply(p.key)) != null) {
5241	>	if (result.compareAndSet(null, u))
5242	>	quietlyCompleteRoot();
5243	>	break;
5244	>	}
5245	>	}
5246	>	}
5247		}
5248	<	public void clear() {
5249	<	ConcurrentHashMap.this.clear();
5248	>	}
5249	>
5250	>	@SuppressWarnings("serial")
5251	>	static final class SearchValuesTask<K,V,U>
5252	>	extends BulkTask<K,V,U> {
5253	>	final Function<? super V, ? extends U> searchFunction;
5254	>	final AtomicReference<U> result;
5255	>	SearchValuesTask
5256	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5257	>	Function<? super V, ? extends U> searchFunction,
5258	>	AtomicReference<U> result) {
5259	>	super(p, b, i, f, t);
5260	>	this.searchFunction = searchFunction; this.result = result;
5261	>	}
5262	>	public final U getRawResult() { return result.get(); }
5263	>	public final void compute() {
5264	>	final Function<? super V, ? extends U> searchFunction;
5265	>	final AtomicReference<U> result;
5266	>	if ((searchFunction = this.searchFunction) != null &&
5267	>	(result = this.result) != null) {
5268	>	for (int i = baseIndex, f, h; batch > 0 &&
5269	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5270	>	if (result.get() != null)
5271	>	return;
5272	>	addToPendingCount(1);
5273	>	new SearchValuesTask<K,V,U>
5274	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5275	>	searchFunction, result).fork();
5276	>	}
5277	>	while (result.get() == null) {
5278	>	U u;
5279	>	Node<K,V> p;
5280	>	if ((p = advance()) == null) {
5281	>	propagateCompletion();
5282	>	break;
5283	>	}
5284	>	if ((u = searchFunction.apply(p.val)) != null) {
5285	>	if (result.compareAndSet(null, u))
5286	>	quietlyCompleteRoot();
5287	>	break;
5288	>	}
5289	>	}
5290	>	}
5291		}
5292		}
5293
5294	<	private class Values extends AbstractCollection<V> {
5295	<	public Iterator<V> iterator() {
5296	<	return new ValueIterator();
5294	>	@SuppressWarnings("serial")
5295	>	static final class SearchEntriesTask<K,V,U>
5296	>	extends BulkTask<K,V,U> {
5297	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5298	>	final AtomicReference<U> result;
5299	>	SearchEntriesTask
5300	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5301	>	Function<Entry<K,V>, ? extends U> searchFunction,
5302	>	AtomicReference<U> result) {
5303	>	super(p, b, i, f, t);
5304	>	this.searchFunction = searchFunction; this.result = result;
5305	>	}
5306	>	public final U getRawResult() { return result.get(); }
5307	>	public final void compute() {
5308	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5309	>	final AtomicReference<U> result;
5310	>	if ((searchFunction = this.searchFunction) != null &&
5311	>	(result = this.result) != null) {
5312	>	for (int i = baseIndex, f, h; batch > 0 &&
5313	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5314	>	if (result.get() != null)
5315	>	return;
5316	>	addToPendingCount(1);
5317	>	new SearchEntriesTask<K,V,U>
5318	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5319	>	searchFunction, result).fork();
5320	>	}
5321	>	while (result.get() == null) {
5322	>	U u;
5323	>	Node<K,V> p;
5324	>	if ((p = advance()) == null) {
5325	>	propagateCompletion();
5326	>	break;
5327	>	}
5328	>	if ((u = searchFunction.apply(p)) != null) {
5329	>	if (result.compareAndSet(null, u))
5330	>	quietlyCompleteRoot();
5331	>	return;
5332	>	}
5333	>	}
5334	>	}
5335		}
5336	<	public int size() {
5337	<	return ConcurrentHashMap.this.size();
5336	>	}
5337	>
5338	>	@SuppressWarnings("serial")
5339	>	static final class SearchMappingsTask<K,V,U>
5340	>	extends BulkTask<K,V,U> {
5341	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5342	>	final AtomicReference<U> result;
5343	>	SearchMappingsTask
5344	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5345	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5346	>	AtomicReference<U> result) {
5347	>	super(p, b, i, f, t);
5348	>	this.searchFunction = searchFunction; this.result = result;
5349	>	}
5350	>	public final U getRawResult() { return result.get(); }
5351	>	public final void compute() {
5352	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5353	>	final AtomicReference<U> result;
5354	>	if ((searchFunction = this.searchFunction) != null &&
5355	>	(result = this.result) != null) {
5356	>	for (int i = baseIndex, f, h; batch > 0 &&
5357	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5358	>	if (result.get() != null)
5359	>	return;
5360	>	addToPendingCount(1);
5361	>	new SearchMappingsTask<K,V,U>
5362	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5363	>	searchFunction, result).fork();
5364	>	}
5365	>	while (result.get() == null) {
5366	>	U u;
5367	>	Node<K,V> p;
5368	>	if ((p = advance()) == null) {
5369	>	propagateCompletion();
5370	>	break;
5371	>	}
5372	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5373	>	if (result.compareAndSet(null, u))
5374	>	quietlyCompleteRoot();
5375	>	break;
5376	>	}
5377	>	}
5378	>	}
5379		}
5380	<	public boolean contains(Object o) {
5381	<	return ConcurrentHashMap.this.containsValue(o);
5380	>	}
5381	>
5382	>	@SuppressWarnings("serial")
5383	>	static final class ReduceKeysTask<K,V>
5384	>	extends BulkTask<K,V,K> {
5385	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5386	>	K result;
5387	>	ReduceKeysTask<K,V> rights, nextRight;
5388	>	ReduceKeysTask
5389	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5390	>	ReduceKeysTask<K,V> nextRight,
5391	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5392	>	super(p, b, i, f, t); this.nextRight = nextRight;
5393	>	this.reducer = reducer;
5394	>	}
5395	>	public final K getRawResult() { return result; }
5396	>	public final void compute() {
5397	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5398	>	if ((reducer = this.reducer) != null) {
5399	>	for (int i = baseIndex, f, h; batch > 0 &&
5400	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5401	>	addToPendingCount(1);
5402	>	(rights = new ReduceKeysTask<K,V>
5403	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5404	>	rights, reducer)).fork();
5405	>	}
5406	>	K r = null;
5407	>	for (Node<K,V> p; (p = advance()) != null; ) {
5408	>	K u = p.key;
5409	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5410	>	}
5411	>	result = r;
5412	>	CountedCompleter<?> c;
5413	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5414	>	@SuppressWarnings("unchecked")
5415	>	ReduceKeysTask<K,V>
5416	>	t = (ReduceKeysTask<K,V>)c,
5417	>	s = t.rights;
5418	>	while (s != null) {
5419	>	K tr, sr;
5420	>	if ((sr = s.result) != null)
5421	>	t.result = (((tr = t.result) == null) ? sr :
5422	>	reducer.apply(tr, sr));
5423	>	s = t.rights = s.nextRight;
5424	>	}
5425	>	}
5426	>	}
5427	>	}
5428	>	}
5429	>
5430	>	@SuppressWarnings("serial")
5431	>	static final class ReduceValuesTask<K,V>
5432	>	extends BulkTask<K,V,V> {
5433	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5434	>	V result;
5435	>	ReduceValuesTask<K,V> rights, nextRight;
5436	>	ReduceValuesTask
5437	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5438	>	ReduceValuesTask<K,V> nextRight,
5439	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5440	>	super(p, b, i, f, t); this.nextRight = nextRight;
5441	>	this.reducer = reducer;
5442	>	}
5443	>	public final V getRawResult() { return result; }
5444	>	public final void compute() {
5445	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5446	>	if ((reducer = this.reducer) != null) {
5447	>	for (int i = baseIndex, f, h; batch > 0 &&
5448	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5449	>	addToPendingCount(1);
5450	>	(rights = new ReduceValuesTask<K,V>
5451	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5452	>	rights, reducer)).fork();
5453	>	}
5454	>	V r = null;
5455	>	for (Node<K,V> p; (p = advance()) != null; ) {
5456	>	V v = p.val;
5457	>	r = (r == null) ? v : reducer.apply(r, v);
5458	>	}
5459	>	result = r;
5460	>	CountedCompleter<?> c;
5461	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5462	>	@SuppressWarnings("unchecked")
5463	>	ReduceValuesTask<K,V>
5464	>	t = (ReduceValuesTask<K,V>)c,
5465	>	s = t.rights;
5466	>	while (s != null) {
5467	>	V tr, sr;
5468	>	if ((sr = s.result) != null)
5469	>	t.result = (((tr = t.result) == null) ? sr :
5470	>	reducer.apply(tr, sr));
5471	>	s = t.rights = s.nextRight;
5472	>	}
5473	>	}
5474	>	}
5475		}
5476	<	public void clear() {
5477	<	ConcurrentHashMap.this.clear();
5476	>	}
5477	>
5478	>	@SuppressWarnings("serial")
5479	>	static final class ReduceEntriesTask<K,V>
5480	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5481	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5482	>	Map.Entry<K,V> result;
5483	>	ReduceEntriesTask<K,V> rights, nextRight;
5484	>	ReduceEntriesTask
5485	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5486	>	ReduceEntriesTask<K,V> nextRight,
5487	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5488	>	super(p, b, i, f, t); this.nextRight = nextRight;
5489	>	this.reducer = reducer;
5490	>	}
5491	>	public final Map.Entry<K,V> getRawResult() { return result; }
5492	>	public final void compute() {
5493	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5494	>	if ((reducer = this.reducer) != null) {
5495	>	for (int i = baseIndex, f, h; batch > 0 &&
5496	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5497	>	addToPendingCount(1);
5498	>	(rights = new ReduceEntriesTask<K,V>
5499	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5500	>	rights, reducer)).fork();
5501	>	}
5502	>	Map.Entry<K,V> r = null;
5503	>	for (Node<K,V> p; (p = advance()) != null; )
5504	>	r = (r == null) ? p : reducer.apply(r, p);
5505	>	result = r;
5506	>	CountedCompleter<?> c;
5507	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5508	>	@SuppressWarnings("unchecked")
5509	>	ReduceEntriesTask<K,V>
5510	>	t = (ReduceEntriesTask<K,V>)c,
5511	>	s = t.rights;
5512	>	while (s != null) {
5513	>	Map.Entry<K,V> tr, sr;
5514	>	if ((sr = s.result) != null)
5515	>	t.result = (((tr = t.result) == null) ? sr :
5516	>	reducer.apply(tr, sr));
5517	>	s = t.rights = s.nextRight;
5518	>	}
5519	>	}
5520	>	}
5521		}
5522		}
5523
5524	<	private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
5525	<	public Iterator<Map.Entry<K,V>> iterator() {
5526	<	return new EntryIterator();
5524	>	@SuppressWarnings("serial")
5525	>	static final class MapReduceKeysTask<K,V,U>
5526	>	extends BulkTask<K,V,U> {
5527	>	final Function<? super K, ? extends U> transformer;
5528	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5529	>	U result;
5530	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5531	>	MapReduceKeysTask
5532	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5533	>	MapReduceKeysTask<K,V,U> nextRight,
5534	>	Function<? super K, ? extends U> transformer,
5535	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5536	>	super(p, b, i, f, t); this.nextRight = nextRight;
5537	>	this.transformer = transformer;
5538	>	this.reducer = reducer;
5539	>	}
5540	>	public final U getRawResult() { return result; }
5541	>	public final void compute() {
5542	>	final Function<? super K, ? extends U> transformer;
5543	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5544	>	if ((transformer = this.transformer) != null &&
5545	>	(reducer = this.reducer) != null) {
5546	>	for (int i = baseIndex, f, h; batch > 0 &&
5547	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5548	>	addToPendingCount(1);
5549	>	(rights = new MapReduceKeysTask<K,V,U>
5550	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5551	>	rights, transformer, reducer)).fork();
5552	>	}
5553	>	U r = null;
5554	>	for (Node<K,V> p; (p = advance()) != null; ) {
5555	>	U u;
5556	>	if ((u = transformer.apply(p.key)) != null)
5557	>	r = (r == null) ? u : reducer.apply(r, u);
5558	>	}
5559	>	result = r;
5560	>	CountedCompleter<?> c;
5561	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5562	>	@SuppressWarnings("unchecked")
5563	>	MapReduceKeysTask<K,V,U>
5564	>	t = (MapReduceKeysTask<K,V,U>)c,
5565	>	s = t.rights;
5566	>	while (s != null) {
5567	>	U tr, sr;
5568	>	if ((sr = s.result) != null)
5569	>	t.result = (((tr = t.result) == null) ? sr :
5570	>	reducer.apply(tr, sr));
5571	>	s = t.rights = s.nextRight;
5572	>	}
5573	>	}
5574	>	}
5575		}
5576	<	public boolean contains(Object o) {
5577	<	if (!(o instanceof Map.Entry))
5578	<	return false;
5579	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5580	<	V v = ConcurrentHashMap.this.get(e.getKey());
5581	<	return v != null && v.equals(e.getValue());
5576	>	}
5577	>
5578	>	@SuppressWarnings("serial")
5579	>	static final class MapReduceValuesTask<K,V,U>
5580	>	extends BulkTask<K,V,U> {
5581	>	final Function<? super V, ? extends U> transformer;
5582	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5583	>	U result;
5584	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5585	>	MapReduceValuesTask
5586	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5587	>	MapReduceValuesTask<K,V,U> nextRight,
5588	>	Function<? super V, ? extends U> transformer,
5589	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5590	>	super(p, b, i, f, t); this.nextRight = nextRight;
5591	>	this.transformer = transformer;
5592	>	this.reducer = reducer;
5593	>	}
5594	>	public final U getRawResult() { return result; }
5595	>	public final void compute() {
5596	>	final Function<? super V, ? extends U> transformer;
5597	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5598	>	if ((transformer = this.transformer) != null &&
5599	>	(reducer = this.reducer) != null) {
5600	>	for (int i = baseIndex, f, h; batch > 0 &&
5601	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5602	>	addToPendingCount(1);
5603	>	(rights = new MapReduceValuesTask<K,V,U>
5604	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5605	>	rights, transformer, reducer)).fork();
5606	>	}
5607	>	U r = null;
5608	>	for (Node<K,V> p; (p = advance()) != null; ) {
5609	>	U u;
5610	>	if ((u = transformer.apply(p.val)) != null)
5611	>	r = (r == null) ? u : reducer.apply(r, u);
5612	>	}
5613	>	result = r;
5614	>	CountedCompleter<?> c;
5615	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5616	>	@SuppressWarnings("unchecked")
5617	>	MapReduceValuesTask<K,V,U>
5618	>	t = (MapReduceValuesTask<K,V,U>)c,
5619	>	s = t.rights;
5620	>	while (s != null) {
5621	>	U tr, sr;
5622	>	if ((sr = s.result) != null)
5623	>	t.result = (((tr = t.result) == null) ? sr :
5624	>	reducer.apply(tr, sr));
5625	>	s = t.rights = s.nextRight;
5626	>	}
5627	>	}
5628	>	}
5629		}
5630	<	public boolean remove(Object o) {
5631	<	if (!(o instanceof Map.Entry))
5632	<	return false;
5633	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5634	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
5630	>	}
5631	>
5632	>	@SuppressWarnings("serial")
5633	>	static final class MapReduceEntriesTask<K,V,U>
5634	>	extends BulkTask<K,V,U> {
5635	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5636	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5637	>	U result;
5638	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5639	>	MapReduceEntriesTask
5640	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5641	>	MapReduceEntriesTask<K,V,U> nextRight,
5642	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5643	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5644	>	super(p, b, i, f, t); this.nextRight = nextRight;
5645	>	this.transformer = transformer;
5646	>	this.reducer = reducer;
5647	>	}
5648	>	public final U getRawResult() { return result; }
5649	>	public final void compute() {
5650	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5651	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5652	>	if ((transformer = this.transformer) != null &&
5653	>	(reducer = this.reducer) != null) {
5654	>	for (int i = baseIndex, f, h; batch > 0 &&
5655	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5656	>	addToPendingCount(1);
5657	>	(rights = new MapReduceEntriesTask<K,V,U>
5658	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5659	>	rights, transformer, reducer)).fork();
5660	>	}
5661	>	U r = null;
5662	>	for (Node<K,V> p; (p = advance()) != null; ) {
5663	>	U u;
5664	>	if ((u = transformer.apply(p)) != null)
5665	>	r = (r == null) ? u : reducer.apply(r, u);
5666	>	}
5667	>	result = r;
5668	>	CountedCompleter<?> c;
5669	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5670	>	@SuppressWarnings("unchecked")
5671	>	MapReduceEntriesTask<K,V,U>
5672	>	t = (MapReduceEntriesTask<K,V,U>)c,
5673	>	s = t.rights;
5674	>	while (s != null) {
5675	>	U tr, sr;
5676	>	if ((sr = s.result) != null)
5677	>	t.result = (((tr = t.result) == null) ? sr :
5678	>	reducer.apply(tr, sr));
5679	>	s = t.rights = s.nextRight;
5680	>	}
5681	>	}
5682	>	}
5683	>	}
5684	>	}
5685	>
5686	>	@SuppressWarnings("serial")
5687	>	static final class MapReduceMappingsTask<K,V,U>
5688	>	extends BulkTask<K,V,U> {
5689	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5690	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5691	>	U result;
5692	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5693	>	MapReduceMappingsTask
5694	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5695	>	MapReduceMappingsTask<K,V,U> nextRight,
5696	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5697	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5698	>	super(p, b, i, f, t); this.nextRight = nextRight;
5699	>	this.transformer = transformer;
5700	>	this.reducer = reducer;
5701	>	}
5702	>	public final U getRawResult() { return result; }
5703	>	public final void compute() {
5704	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5705	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5706	>	if ((transformer = this.transformer) != null &&
5707	>	(reducer = this.reducer) != null) {
5708	>	for (int i = baseIndex, f, h; batch > 0 &&
5709	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5710	>	addToPendingCount(1);
5711	>	(rights = new MapReduceMappingsTask<K,V,U>
5712	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5713	>	rights, transformer, reducer)).fork();
5714	>	}
5715	>	U r = null;
5716	>	for (Node<K,V> p; (p = advance()) != null; ) {
5717	>	U u;
5718	>	if ((u = transformer.apply(p.key, p.val)) != null)
5719	>	r = (r == null) ? u : reducer.apply(r, u);
5720	>	}
5721	>	result = r;
5722	>	CountedCompleter<?> c;
5723	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5724	>	@SuppressWarnings("unchecked")
5725	>	MapReduceMappingsTask<K,V,U>
5726	>	t = (MapReduceMappingsTask<K,V,U>)c,
5727	>	s = t.rights;
5728	>	while (s != null) {
5729	>	U tr, sr;
5730	>	if ((sr = s.result) != null)
5731	>	t.result = (((tr = t.result) == null) ? sr :
5732	>	reducer.apply(tr, sr));
5733	>	s = t.rights = s.nextRight;
5734	>	}
5735	>	}
5736	>	}
5737	>	}
5738	>	}
5739	>
5740	>	@SuppressWarnings("serial")
5741	>	static final class MapReduceKeysToDoubleTask<K,V>
5742	>	extends BulkTask<K,V,Double> {
5743	>	final ToDoubleFunction<? super K> transformer;
5744	>	final DoubleBinaryOperator reducer;
5745	>	final double basis;
5746	>	double result;
5747	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5748	>	MapReduceKeysToDoubleTask
5749	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5750	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5751	>	ToDoubleFunction<? super K> transformer,
5752	>	double basis,
5753	>	DoubleBinaryOperator reducer) {
5754	>	super(p, b, i, f, t); this.nextRight = nextRight;
5755	>	this.transformer = transformer;
5756	>	this.basis = basis; this.reducer = reducer;
5757	>	}
5758	>	public final Double getRawResult() { return result; }
5759	>	public final void compute() {
5760	>	final ToDoubleFunction<? super K> transformer;
5761	>	final DoubleBinaryOperator reducer;
5762	>	if ((transformer = this.transformer) != null &&
5763	>	(reducer = this.reducer) != null) {
5764	>	double r = this.basis;
5765	>	for (int i = baseIndex, f, h; batch > 0 &&
5766	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5767	>	addToPendingCount(1);
5768	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5769	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5770	>	rights, transformer, r, reducer)).fork();
5771	>	}
5772	>	for (Node<K,V> p; (p = advance()) != null; )
5773	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5774	>	result = r;
5775	>	CountedCompleter<?> c;
5776	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5777	>	@SuppressWarnings("unchecked")
5778	>	MapReduceKeysToDoubleTask<K,V>
5779	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5780	>	s = t.rights;
5781	>	while (s != null) {
5782	>	t.result = reducer.applyAsDouble(t.result, s.result);
5783	>	s = t.rights = s.nextRight;
5784	>	}
5785	>	}
5786	>	}
5787		}
5788	<	public int size() {
5789	<	return ConcurrentHashMap.this.size();
5788	>	}
5789	>
5790	>	@SuppressWarnings("serial")
5791	>	static final class MapReduceValuesToDoubleTask<K,V>
5792	>	extends BulkTask<K,V,Double> {
5793	>	final ToDoubleFunction<? super V> transformer;
5794	>	final DoubleBinaryOperator reducer;
5795	>	final double basis;
5796	>	double result;
5797	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5798	>	MapReduceValuesToDoubleTask
5799	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5800	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5801	>	ToDoubleFunction<? super V> transformer,
5802	>	double basis,
5803	>	DoubleBinaryOperator reducer) {
5804	>	super(p, b, i, f, t); this.nextRight = nextRight;
5805	>	this.transformer = transformer;
5806	>	this.basis = basis; this.reducer = reducer;
5807	>	}
5808	>	public final Double getRawResult() { return result; }
5809	>	public final void compute() {
5810	>	final ToDoubleFunction<? super V> transformer;
5811	>	final DoubleBinaryOperator reducer;
5812	>	if ((transformer = this.transformer) != null &&
5813	>	(reducer = this.reducer) != null) {
5814	>	double r = this.basis;
5815	>	for (int i = baseIndex, f, h; batch > 0 &&
5816	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5817	>	addToPendingCount(1);
5818	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5819	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5820	>	rights, transformer, r, reducer)).fork();
5821	>	}
5822	>	for (Node<K,V> p; (p = advance()) != null; )
5823	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5824	>	result = r;
5825	>	CountedCompleter<?> c;
5826	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5827	>	@SuppressWarnings("unchecked")
5828	>	MapReduceValuesToDoubleTask<K,V>
5829	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5830	>	s = t.rights;
5831	>	while (s != null) {
5832	>	t.result = reducer.applyAsDouble(t.result, s.result);
5833	>	s = t.rights = s.nextRight;
5834	>	}
5835	>	}
5836	>	}
5837		}
5838	<	public void clear() {
5839	<	ConcurrentHashMap.this.clear();
5838	>	}
5839	>
5840	>	@SuppressWarnings("serial")
5841	>	static final class MapReduceEntriesToDoubleTask<K,V>
5842	>	extends BulkTask<K,V,Double> {
5843	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5844	>	final DoubleBinaryOperator reducer;
5845	>	final double basis;
5846	>	double result;
5847	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5848	>	MapReduceEntriesToDoubleTask
5849	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5850	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5851	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5852	>	double basis,
5853	>	DoubleBinaryOperator reducer) {
5854	>	super(p, b, i, f, t); this.nextRight = nextRight;
5855	>	this.transformer = transformer;
5856	>	this.basis = basis; this.reducer = reducer;
5857	>	}
5858	>	public final Double getRawResult() { return result; }
5859	>	public final void compute() {
5860	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5861	>	final DoubleBinaryOperator reducer;
5862	>	if ((transformer = this.transformer) != null &&
5863	>	(reducer = this.reducer) != null) {
5864	>	double r = this.basis;
5865	>	for (int i = baseIndex, f, h; batch > 0 &&
5866	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5867	>	addToPendingCount(1);
5868	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5869	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5870	>	rights, transformer, r, reducer)).fork();
5871	>	}
5872	>	for (Node<K,V> p; (p = advance()) != null; )
5873	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5874	>	result = r;
5875	>	CountedCompleter<?> c;
5876	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5877	>	@SuppressWarnings("unchecked")
5878	>	MapReduceEntriesToDoubleTask<K,V>
5879	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5880	>	s = t.rights;
5881	>	while (s != null) {
5882	>	t.result = reducer.applyAsDouble(t.result, s.result);
5883	>	s = t.rights = s.nextRight;
5884	>	}
5885	>	}
5886	>	}
5887		}
5888		}
5889
5890	<	/* ---------------- Serialization Support -------------- */
5890	>	@SuppressWarnings("serial")
5891	>	static final class MapReduceMappingsToDoubleTask<K,V>
5892	>	extends BulkTask<K,V,Double> {
5893	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5894	>	final DoubleBinaryOperator reducer;
5895	>	final double basis;
5896	>	double result;
5897	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5898	>	MapReduceMappingsToDoubleTask
5899	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5900	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5901	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5902	>	double basis,
5903	>	DoubleBinaryOperator reducer) {
5904	>	super(p, b, i, f, t); this.nextRight = nextRight;
5905	>	this.transformer = transformer;
5906	>	this.basis = basis; this.reducer = reducer;
5907	>	}
5908	>	public final Double getRawResult() { return result; }
5909	>	public final void compute() {
5910	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5911	>	final DoubleBinaryOperator reducer;
5912	>	if ((transformer = this.transformer) != null &&
5913	>	(reducer = this.reducer) != null) {
5914	>	double r = this.basis;
5915	>	for (int i = baseIndex, f, h; batch > 0 &&
5916	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5917	>	addToPendingCount(1);
5918	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5919	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5920	>	rights, transformer, r, reducer)).fork();
5921	>	}
5922	>	for (Node<K,V> p; (p = advance()) != null; )
5923	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5924	>	result = r;
5925	>	CountedCompleter<?> c;
5926	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5927	>	@SuppressWarnings("unchecked")
5928	>	MapReduceMappingsToDoubleTask<K,V>
5929	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5930	>	s = t.rights;
5931	>	while (s != null) {
5932	>	t.result = reducer.applyAsDouble(t.result, s.result);
5933	>	s = t.rights = s.nextRight;
5934	>	}
5935	>	}
5936	>	}
5937	>	}
5938	>	}
5939
5940	<	/**
5941	<	* Save the state of the <tt>ConcurrentHashMap</tt>
5942	<	* instance to a stream (i.e.,
5943	<	* serialize it).
5944	<	* @param s the stream
5945	<	* @serialData
5946	<	* the key (Object) and value (Object)
5947	<	* for each key-value mapping, followed by a null pair.
5948	<	* The key-value mappings are emitted in no particular order.
5949	<	*/
5950	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
5951	<	s.defaultWriteObject();
5940	>	@SuppressWarnings("serial")
5941	>	static final class MapReduceKeysToLongTask<K,V>
5942	>	extends BulkTask<K,V,Long> {
5943	>	final ToLongFunction<? super K> transformer;
5944	>	final LongBinaryOperator reducer;
5945	>	final long basis;
5946	>	long result;
5947	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5948	>	MapReduceKeysToLongTask
5949	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5950	>	MapReduceKeysToLongTask<K,V> nextRight,
5951	>	ToLongFunction<? super K> transformer,
5952	>	long basis,
5953	>	LongBinaryOperator reducer) {
5954	>	super(p, b, i, f, t); this.nextRight = nextRight;
5955	>	this.transformer = transformer;
5956	>	this.basis = basis; this.reducer = reducer;
5957	>	}
5958	>	public final Long getRawResult() { return result; }
5959	>	public final void compute() {
5960	>	final ToLongFunction<? super K> transformer;
5961	>	final LongBinaryOperator reducer;
5962	>	if ((transformer = this.transformer) != null &&
5963	>	(reducer = this.reducer) != null) {
5964	>	long r = this.basis;
5965	>	for (int i = baseIndex, f, h; batch > 0 &&
5966	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5967	>	addToPendingCount(1);
5968	>	(rights = new MapReduceKeysToLongTask<K,V>
5969	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5970	>	rights, transformer, r, reducer)).fork();
5971	>	}
5972	>	for (Node<K,V> p; (p = advance()) != null; )
5973	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5974	>	result = r;
5975	>	CountedCompleter<?> c;
5976	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5977	>	@SuppressWarnings("unchecked")
5978	>	MapReduceKeysToLongTask<K,V>
5979	>	t = (MapReduceKeysToLongTask<K,V>)c,
5980	>	s = t.rights;
5981	>	while (s != null) {
5982	>	t.result = reducer.applyAsLong(t.result, s.result);
5983	>	s = t.rights = s.nextRight;
5984	>	}
5985	>	}
5986	>	}
5987	>	}
5988	>	}
5989
5990	<	for (int k = 0; k < segments.length; ++k) {
5991	<	Segment<K,V> seg = (Segment<K,V>)segments[k];
5992	<	seg.lock();
5993	<	try {
5994	<	HashEntry[] tab = seg.table;
5995	<	for (int i = 0; i < tab.length; ++i) {
5996	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i]; e != null; e = e.next) {
5997	<	s.writeObject(e.key);
5998	<	s.writeObject(e.value);
5990	>	@SuppressWarnings("serial")
5991	>	static final class MapReduceValuesToLongTask<K,V>
5992	>	extends BulkTask<K,V,Long> {
5993	>	final ToLongFunction<? super V> transformer;
5994	>	final LongBinaryOperator reducer;
5995	>	final long basis;
5996	>	long result;
5997	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5998	>	MapReduceValuesToLongTask
5999	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6000	>	MapReduceValuesToLongTask<K,V> nextRight,
6001	>	ToLongFunction<? super V> transformer,
6002	>	long basis,
6003	>	LongBinaryOperator reducer) {
6004	>	super(p, b, i, f, t); this.nextRight = nextRight;
6005	>	this.transformer = transformer;
6006	>	this.basis = basis; this.reducer = reducer;
6007	>	}
6008	>	public final Long getRawResult() { return result; }
6009	>	public final void compute() {
6010	>	final ToLongFunction<? super V> transformer;
6011	>	final LongBinaryOperator reducer;
6012	>	if ((transformer = this.transformer) != null &&
6013	>	(reducer = this.reducer) != null) {
6014	>	long r = this.basis;
6015	>	for (int i = baseIndex, f, h; batch > 0 &&
6016	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6017	>	addToPendingCount(1);
6018	>	(rights = new MapReduceValuesToLongTask<K,V>
6019	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6020	>	rights, transformer, r, reducer)).fork();
6021	>	}
6022	>	for (Node<K,V> p; (p = advance()) != null; )
6023	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
6024	>	result = r;
6025	>	CountedCompleter<?> c;
6026	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6027	>	@SuppressWarnings("unchecked")
6028	>	MapReduceValuesToLongTask<K,V>
6029	>	t = (MapReduceValuesToLongTask<K,V>)c,
6030	>	s = t.rights;
6031	>	while (s != null) {
6032	>	t.result = reducer.applyAsLong(t.result, s.result);
6033	>	s = t.rights = s.nextRight;
6034		}
6035		}
1100	–	} finally {
1101	–	seg.unlock();
6036		}
6037		}
1104	–	s.writeObject(null);
1105	–	s.writeObject(null);
6038		}
6039
6040	<	/**
6041	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
6042	<	* instance from a stream (i.e.,
6043	<	* deserialize it).
6044	<	* @param s the stream
6045	<	*/
6046	<	private void readObject(java.io.ObjectInputStream s)
6047	<	throws IOException, ClassNotFoundException  {
6048	<	s.defaultReadObject();
6040	>	@SuppressWarnings("serial")
6041	>	static final class MapReduceEntriesToLongTask<K,V>
6042	>	extends BulkTask<K,V,Long> {
6043	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6044	>	final LongBinaryOperator reducer;
6045	>	final long basis;
6046	>	long result;
6047	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6048	>	MapReduceEntriesToLongTask
6049	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6050	>	MapReduceEntriesToLongTask<K,V> nextRight,
6051	>	ToLongFunction<Map.Entry<K,V>> transformer,
6052	>	long basis,
6053	>	LongBinaryOperator reducer) {
6054	>	super(p, b, i, f, t); this.nextRight = nextRight;
6055	>	this.transformer = transformer;
6056	>	this.basis = basis; this.reducer = reducer;
6057	>	}
6058	>	public final Long getRawResult() { return result; }
6059	>	public final void compute() {
6060	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6061	>	final LongBinaryOperator reducer;
6062	>	if ((transformer = this.transformer) != null &&
6063	>	(reducer = this.reducer) != null) {
6064	>	long r = this.basis;
6065	>	for (int i = baseIndex, f, h; batch > 0 &&
6066	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6067	>	addToPendingCount(1);
6068	>	(rights = new MapReduceEntriesToLongTask<K,V>
6069	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6070	>	rights, transformer, r, reducer)).fork();
6071	>	}
6072	>	for (Node<K,V> p; (p = advance()) != null; )
6073	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6074	>	result = r;
6075	>	CountedCompleter<?> c;
6076	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6077	>	@SuppressWarnings("unchecked")
6078	>	MapReduceEntriesToLongTask<K,V>
6079	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6080	>	s = t.rights;
6081	>	while (s != null) {
6082	>	t.result = reducer.applyAsLong(t.result, s.result);
6083	>	s = t.rights = s.nextRight;
6084	>	}
6085	>	}
6086	>	}
6087	>	}
6088	>	}
6089
6090	<	// Initialize each segment to be minimally sized, and let grow.
6091	<	for (int i = 0; i < segments.length; ++i) {
6092	<	segments[i].setTable(new HashEntry[1]);
6090	>	@SuppressWarnings("serial")
6091	>	static final class MapReduceMappingsToLongTask<K,V>
6092	>	extends BulkTask<K,V,Long> {
6093	>	final ToLongBiFunction<? super K, ? super V> transformer;
6094	>	final LongBinaryOperator reducer;
6095	>	final long basis;
6096	>	long result;
6097	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6098	>	MapReduceMappingsToLongTask
6099	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6100	>	MapReduceMappingsToLongTask<K,V> nextRight,
6101	>	ToLongBiFunction<? super K, ? super V> transformer,
6102	>	long basis,
6103	>	LongBinaryOperator reducer) {
6104	>	super(p, b, i, f, t); this.nextRight = nextRight;
6105	>	this.transformer = transformer;
6106	>	this.basis = basis; this.reducer = reducer;
6107	>	}
6108	>	public final Long getRawResult() { return result; }
6109	>	public final void compute() {
6110	>	final ToLongBiFunction<? super K, ? super V> transformer;
6111	>	final LongBinaryOperator reducer;
6112	>	if ((transformer = this.transformer) != null &&
6113	>	(reducer = this.reducer) != null) {
6114	>	long r = this.basis;
6115	>	for (int i = baseIndex, f, h; batch > 0 &&
6116	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6117	>	addToPendingCount(1);
6118	>	(rights = new MapReduceMappingsToLongTask<K,V>
6119	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6120	>	rights, transformer, r, reducer)).fork();
6121	>	}
6122	>	for (Node<K,V> p; (p = advance()) != null; )
6123	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6124	>	result = r;
6125	>	CountedCompleter<?> c;
6126	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6127	>	@SuppressWarnings("unchecked")
6128	>	MapReduceMappingsToLongTask<K,V>
6129	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6130	>	s = t.rights;
6131	>	while (s != null) {
6132	>	t.result = reducer.applyAsLong(t.result, s.result);
6133	>	s = t.rights = s.nextRight;
6134	>	}
6135	>	}
6136	>	}
6137		}
6138	+	}
6139
6140	<	// Read the keys and values, and put the mappings in the table
6141	<	for (;;) {
6142	<	K key = (K) s.readObject();
6143	<	V value = (V) s.readObject();
6144	<	if (key == null)
6145	<	break;
6146	<	put(key, value);
6140	>	@SuppressWarnings("serial")
6141	>	static final class MapReduceKeysToIntTask<K,V>
6142	>	extends BulkTask<K,V,Integer> {
6143	>	final ToIntFunction<? super K> transformer;
6144	>	final IntBinaryOperator reducer;
6145	>	final int basis;
6146	>	int result;
6147	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6148	>	MapReduceKeysToIntTask
6149	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6150	>	MapReduceKeysToIntTask<K,V> nextRight,
6151	>	ToIntFunction<? super K> transformer,
6152	>	int basis,
6153	>	IntBinaryOperator reducer) {
6154	>	super(p, b, i, f, t); this.nextRight = nextRight;
6155	>	this.transformer = transformer;
6156	>	this.basis = basis; this.reducer = reducer;
6157	>	}
6158	>	public final Integer getRawResult() { return result; }
6159	>	public final void compute() {
6160	>	final ToIntFunction<? super K> transformer;
6161	>	final IntBinaryOperator reducer;
6162	>	if ((transformer = this.transformer) != null &&
6163	>	(reducer = this.reducer) != null) {
6164	>	int r = this.basis;
6165	>	for (int i = baseIndex, f, h; batch > 0 &&
6166	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6167	>	addToPendingCount(1);
6168	>	(rights = new MapReduceKeysToIntTask<K,V>
6169	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6170	>	rights, transformer, r, reducer)).fork();
6171	>	}
6172	>	for (Node<K,V> p; (p = advance()) != null; )
6173	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6174	>	result = r;
6175	>	CountedCompleter<?> c;
6176	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6177	>	@SuppressWarnings("unchecked")
6178	>	MapReduceKeysToIntTask<K,V>
6179	>	t = (MapReduceKeysToIntTask<K,V>)c,
6180	>	s = t.rights;
6181	>	while (s != null) {
6182	>	t.result = reducer.applyAsInt(t.result, s.result);
6183	>	s = t.rights = s.nextRight;
6184	>	}
6185	>	}
6186	>	}
6187		}
6188		}
1132	–	}
6189
6190	+	@SuppressWarnings("serial")
6191	+	static final class MapReduceValuesToIntTask<K,V>
6192	+	extends BulkTask<K,V,Integer> {
6193	+	final ToIntFunction<? super V> transformer;
6194	+	final IntBinaryOperator reducer;
6195	+	final int basis;
6196	+	int result;
6197	+	MapReduceValuesToIntTask<K,V> rights, nextRight;
6198	+	MapReduceValuesToIntTask
6199	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6200	+	MapReduceValuesToIntTask<K,V> nextRight,
6201	+	ToIntFunction<? super V> transformer,
6202	+	int basis,
6203	+	IntBinaryOperator reducer) {
6204	+	super(p, b, i, f, t); this.nextRight = nextRight;
6205	+	this.transformer = transformer;
6206	+	this.basis = basis; this.reducer = reducer;
6207	+	}
6208	+	public final Integer getRawResult() { return result; }
6209	+	public final void compute() {
6210	+	final ToIntFunction<? super V> transformer;
6211	+	final IntBinaryOperator reducer;
6212	+	if ((transformer = this.transformer) != null &&
6213	+	(reducer = this.reducer) != null) {
6214	+	int r = this.basis;
6215	+	for (int i = baseIndex, f, h; batch > 0 &&
6216	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6217	+	addToPendingCount(1);
6218	+	(rights = new MapReduceValuesToIntTask<K,V>
6219	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6220	+	rights, transformer, r, reducer)).fork();
6221	+	}
6222	+	for (Node<K,V> p; (p = advance()) != null; )
6223	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6224	+	result = r;
6225	+	CountedCompleter<?> c;
6226	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6227	+	@SuppressWarnings("unchecked")
6228	+	MapReduceValuesToIntTask<K,V>
6229	+	t = (MapReduceValuesToIntTask<K,V>)c,
6230	+	s = t.rights;
6231	+	while (s != null) {
6232	+	t.result = reducer.applyAsInt(t.result, s.result);
6233	+	s = t.rights = s.nextRight;
6234	+	}
6235	+	}
6236	+	}
6237	+	}
6238	+	}
6239	+
6240	+	@SuppressWarnings("serial")
6241	+	static final class MapReduceEntriesToIntTask<K,V>
6242	+	extends BulkTask<K,V,Integer> {
6243	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6244	+	final IntBinaryOperator reducer;
6245	+	final int basis;
6246	+	int result;
6247	+	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6248	+	MapReduceEntriesToIntTask
6249	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6250	+	MapReduceEntriesToIntTask<K,V> nextRight,
6251	+	ToIntFunction<Map.Entry<K,V>> transformer,
6252	+	int basis,
6253	+	IntBinaryOperator reducer) {
6254	+	super(p, b, i, f, t); this.nextRight = nextRight;
6255	+	this.transformer = transformer;
6256	+	this.basis = basis; this.reducer = reducer;
6257	+	}
6258	+	public final Integer getRawResult() { return result; }
6259	+	public final void compute() {
6260	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6261	+	final IntBinaryOperator reducer;
6262	+	if ((transformer = this.transformer) != null &&
6263	+	(reducer = this.reducer) != null) {
6264	+	int r = this.basis;
6265	+	for (int i = baseIndex, f, h; batch > 0 &&
6266	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6267	+	addToPendingCount(1);
6268	+	(rights = new MapReduceEntriesToIntTask<K,V>
6269	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6270	+	rights, transformer, r, reducer)).fork();
6271	+	}
6272	+	for (Node<K,V> p; (p = advance()) != null; )
6273	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6274	+	result = r;
6275	+	CountedCompleter<?> c;
6276	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6277	+	@SuppressWarnings("unchecked")
6278	+	MapReduceEntriesToIntTask<K,V>
6279	+	t = (MapReduceEntriesToIntTask<K,V>)c,
6280	+	s = t.rights;
6281	+	while (s != null) {
6282	+	t.result = reducer.applyAsInt(t.result, s.result);
6283	+	s = t.rights = s.nextRight;
6284	+	}
6285	+	}
6286	+	}
6287	+	}
6288	+	}
6289	+
6290	+	@SuppressWarnings("serial")
6291	+	static final class MapReduceMappingsToIntTask<K,V>
6292	+	extends BulkTask<K,V,Integer> {
6293	+	final ToIntBiFunction<? super K, ? super V> transformer;
6294	+	final IntBinaryOperator reducer;
6295	+	final int basis;
6296	+	int result;
6297	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6298	+	MapReduceMappingsToIntTask
6299	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6300	+	MapReduceMappingsToIntTask<K,V> nextRight,
6301	+	ToIntBiFunction<? super K, ? super V> transformer,
6302	+	int basis,
6303	+	IntBinaryOperator reducer) {
6304	+	super(p, b, i, f, t); this.nextRight = nextRight;
6305	+	this.transformer = transformer;
6306	+	this.basis = basis; this.reducer = reducer;
6307	+	}
6308	+	public final Integer getRawResult() { return result; }
6309	+	public final void compute() {
6310	+	final ToIntBiFunction<? super K, ? super V> transformer;
6311	+	final IntBinaryOperator reducer;
6312	+	if ((transformer = this.transformer) != null &&
6313	+	(reducer = this.reducer) != null) {
6314	+	int r = this.basis;
6315	+	for (int i = baseIndex, f, h; batch > 0 &&
6316	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6317	+	addToPendingCount(1);
6318	+	(rights = new MapReduceMappingsToIntTask<K,V>
6319	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6320	+	rights, transformer, r, reducer)).fork();
6321	+	}
6322	+	for (Node<K,V> p; (p = advance()) != null; )
6323	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6324	+	result = r;
6325	+	CountedCompleter<?> c;
6326	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6327	+	@SuppressWarnings("unchecked")
6328	+	MapReduceMappingsToIntTask<K,V>
6329	+	t = (MapReduceMappingsToIntTask<K,V>)c,
6330	+	s = t.rights;
6331	+	while (s != null) {
6332	+	t.result = reducer.applyAsInt(t.result, s.result);
6333	+	s = t.rights = s.nextRight;
6334	+	}
6335	+	}
6336	+	}
6337	+	}
6338	+	}
6339	+
6340	+	// Unsafe mechanics
6341	+	private static final Unsafe U = Unsafe.getUnsafe();
6342	+	private static final long SIZECTL;
6343	+	private static final long TRANSFERINDEX;
6344	+	private static final long BASECOUNT;
6345	+	private static final long CELLSBUSY;
6346	+	private static final long CELLVALUE;
6347	+	private static final int ABASE;
6348	+	private static final int ASHIFT;
6349	+
6350	+	static {
6351	+	try {
6352	+	SIZECTL = U.objectFieldOffset
6353	+	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6354	+	TRANSFERINDEX = U.objectFieldOffset
6355	+	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6356	+	BASECOUNT = U.objectFieldOffset
6357	+	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6358	+	CELLSBUSY = U.objectFieldOffset
6359	+	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6360	+
6361	+	CELLVALUE = U.objectFieldOffset
6362	+	(CounterCell.class.getDeclaredField("value"));
6363	+
6364	+	ABASE = U.arrayBaseOffset(Node[].class);
6365	+	int scale = U.arrayIndexScale(Node[].class);
6366	+	if ((scale & (scale - 1)) != 0)
6367	+	throw new Error("array index scale not a power of two");
6368	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6369	+	} catch (ReflectiveOperationException e) {
6370	+	throw new Error(e);
6371	+	}
6372	+
6373	+	// Reduce the risk of rare disastrous classloading in first call to
6374	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6375	+	Class<?> ensureLoaded = LockSupport.class;
6376	+	}
6377	+	}

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