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Revision 1.33 by dl, Sat Dec 6 00:16:20 2003 UTC vs.
Revision 1.276 by jsr166, Sat Sep 12 19:25:31 2015 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
43		/**
44		* A hash table supporting full concurrency of retrievals and
45	<	* adjustable expected concurrency for updates. This class obeys the
45	>	* high expected concurrency for updates. This class obeys the
46		* same functional specification as {@link java.util.Hashtable}, and
47		* includes versions of methods corresponding to each method of
48	<	* <tt>Hashtable</tt>. However, even though all operations are
48	>	* {@code Hashtable}. However, even though all operations are
49		* thread-safe, retrieval operations do <em>not</em> entail locking,
50		* and there is <em>not</em> any support for locking the entire table
51		* in a way that prevents all access.  This class is fully
52	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
52	>	* interoperable with {@code Hashtable} in programs that rely on its
53		* thread safety but not on its synchronization details.
54		*
55	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
56	<	* block, so may overlap with update operations (including
57	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
58	<	* of the most recently <em>completed</em> update operations holding
59	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
60	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
61	<	* removal of only some entries.  Similarly, Iterators and
62	<	* Enumerations return elements reflecting the state of the hash table
63	<	* at some point at or since the creation of the iterator/enumeration.
64	<	* They do <em>not</em> throw
65	<	* {@link ConcurrentModificationException}.  However, iterators are
66	<	* designed to be used by only one thread at a time.
67	<	*
68	<	* <p> The allowed concurrency among update operations is guided by
69	<	* the optional <tt>concurrencyLevel</tt> constructor argument
70	<	* (default 16), which is used as a hint for internal sizing.  The
71	<	* table is internally partitioned to try to permit the indicated
72	<	* number of concurrent updates without contention. Because placement
73	<	* in hash tables is essentially random, the actual concurrency will
74	<	* vary.  Ideally, you should choose a value to accommodate as many
75	<	* threads as will ever concurrently modify the table. Using a
76	<	* significantly higher value than you need can waste space and time,
77	<	* and a significantly lower value can lead to thread contention. But
78	<	* overestimates and underestimates within an order of magnitude do
79	<	* not usually have much noticeable impact. A value of one is
80	<	* appropriate when it is known that only one thread will modify
81	<	* and all others will only read.
82	<	*
83	<	* <p>This class implements all of the <em>optional</em> methods
84	<	* of the {@link Map} and {@link Iterator} interfaces.
85	<	*
86	<	* <p> Like {@link java.util.Hashtable} but unlike {@link
87	<	* java.util.HashMap}, this class does NOT allow <tt>null</tt> to be
88	<	* used as a key or value.
55	>	* <p>Retrieval operations (including {@code get}) generally do not
56	>	* block, so may overlap with update operations (including {@code put}
57	>	* and {@code remove}). Retrievals reflect the results of the most
58	>	* recently <em>completed</em> update operations holding upon their
59	>	* onset. (More formally, an update operation for a given key bears a
60	>	* <em>happens-before</em> relation with any (non-null) retrieval for
61	>	* that key reporting the updated value.)  For aggregate operations
62	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
63	>	* reflect insertion or removal of only some entries.  Similarly,
64	>	* Iterators, Spliterators and Enumerations return elements reflecting the
65	>	* state of the hash table at some point at or since the creation of the
66	>	* iterator/enumeration.  They do <em>not</em> throw {@link
67	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
68	>	* However, iterators are designed to be used by only one thread at a time.
69	>	* Bear in mind that the results of aggregate status methods including
70	>	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
71	>	* useful only when a map is not undergoing concurrent updates in other threads.
72	>	* Otherwise the results of these methods reflect transient states
73	>	* that may be adequate for monitoring or estimation purposes, but not
74	>	* for program control.
75	>	*
76	>	* <p>The table is dynamically expanded when there are too many
77	>	* collisions (i.e., keys that have distinct hash codes but fall into
78	>	* the same slot modulo the table size), with the expected average
79	>	* effect of maintaining roughly two bins per mapping (corresponding
80	>	* to a 0.75 load factor threshold for resizing). There may be much
81	>	* variance around this average as mappings are added and removed, but
82	>	* overall, this maintains a commonly accepted time/space tradeoff for
83	>	* hash tables.  However, resizing this or any other kind of hash
84	>	* table may be a relatively slow operation. When possible, it is a
85	>	* good idea to provide a size estimate as an optional {@code
86	>	* initialCapacity} constructor argument. An additional optional
87	>	* {@code loadFactor} constructor argument provides a further means of
88	>	* customizing initial table capacity by specifying the table density
89	>	* to be used in calculating the amount of space to allocate for the
90	>	* given number of elements.  Also, for compatibility with previous
91	>	* versions of this class, constructors may optionally specify an
92	>	* expected {@code concurrencyLevel} as an additional hint for
93	>	* internal sizing.  Note that using many keys with exactly the same
94	>	* {@code hashCode()} is a sure way to slow down performance of any
95	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
96	>	* this class may use comparison order among keys to help break ties.
97	>	*
98	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
99	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
100	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
101	>	* mapped values are (perhaps transiently) not used or all take the
102	>	* same mapping value.
103	>	*
104	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
105	>	* form of histogram or multiset) by using {@link
106	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
107	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
108	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
109	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
110	>	*
111	>	* <p>This class and its views and iterators implement all of the
112	>	* <em>optional</em> methods of the {@link Map} and {@link Iterator}
113	>	* interfaces.
114	>	*
115	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
116	>	* does <em>not</em> allow {@code null} to be used as a key or value.
117	>	*
118	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
119	>	* operations that, unlike most {@link Stream} methods, are designed
120	>	* to be safely, and often sensibly, applied even with maps that are
121	>	* being concurrently updated by other threads; for example, when
122	>	* computing a snapshot summary of the values in a shared registry.
123	>	* There are three kinds of operation, each with four forms, accepting
124	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
125	>	* and/or return values. Because the elements of a ConcurrentHashMap
126	>	* are not ordered in any particular way, and may be processed in
127	>	* different orders in different parallel executions, the correctness
128	>	* of supplied functions should not depend on any ordering, or on any
129	>	* other objects or values that may transiently change while
130	>	* computation is in progress; and except for forEach actions, should
131	>	* ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry}
132	>	* objects do not support method {@code setValue}.
133	>	*
134	>	* <ul>
135	>	* <li> forEach: Perform a given action on each element.
136	>	* A variant form applies a given transformation on each element
137	>	* before performing the action.</li>
138	>	*
139	>	* <li> search: Return the first available non-null result of
140	>	* applying a given function on each element; skipping further
141	>	* search when a result is found.</li>
142	>	*
143	>	* <li> reduce: Accumulate each element.  The supplied reduction
144	>	* function cannot rely on ordering (more formally, it should be
145	>	* both associative and commutative).  There are five variants:
146	>	*
147	>	* <ul>
148	>	*
149	>	* <li> Plain reductions. (There is not a form of this method for
150	>	* (key, value) function arguments since there is no corresponding
151	>	* return type.)</li>
152	>	*
153	>	* <li> Mapped reductions that accumulate the results of a given
154	>	* function applied to each element.</li>
155	>	*
156	>	* <li> Reductions to scalar doubles, longs, and ints, using a
157	>	* given basis value.</li>
158	>	*
159	>	* </ul>
160	>	* </li>
161	>	* </ul>
162	>	*
163	>	* <p>These bulk operations accept a {@code parallelismThreshold}
164	>	* argument. Methods proceed sequentially if the current map size is
165	>	* estimated to be less than the given threshold. Using a value of
166	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
167	>	* of {@code 1} results in maximal parallelism by partitioning into
168	>	* enough subtasks to fully utilize the {@link
169	>	* ForkJoinPool#commonPool()} that is used for all parallel
170	>	* computations. Normally, you would initially choose one of these
171	>	* extreme values, and then measure performance of using in-between
172	>	* values that trade off overhead versus throughput.
173	>	*
174	>	* <p>The concurrency properties of bulk operations follow
175	>	* from those of ConcurrentHashMap: Any non-null result returned
176	>	* from {@code get(key)} and related access methods bears a
177	>	* happens-before relation with the associated insertion or
178	>	* update.  The result of any bulk operation reflects the
179	>	* composition of these per-element relations (but is not
180	>	* necessarily atomic with respect to the map as a whole unless it
181	>	* is somehow known to be quiescent).  Conversely, because keys
182	>	* and values in the map are never null, null serves as a reliable
183	>	* atomic indicator of the current lack of any result.  To
184	>	* maintain this property, null serves as an implicit basis for
185	>	* all non-scalar reduction operations. For the double, long, and
186	>	* int versions, the basis should be one that, when combined with
187	>	* any other value, returns that other value (more formally, it
188	>	* should be the identity element for the reduction). Most common
189	>	* reductions have these properties; for example, computing a sum
190	>	* with basis 0 or a minimum with basis MAX_VALUE.
191	>	*
192	>	* <p>Search and transformation functions provided as arguments
193	>	* should similarly return null to indicate the lack of any result
194	>	* (in which case it is not used). In the case of mapped
195	>	* reductions, this also enables transformations to serve as
196	>	* filters, returning null (or, in the case of primitive
197	>	* specializations, the identity basis) if the element should not
198	>	* be combined. You can create compound transformations and
199	>	* filterings by composing them yourself under this "null means
200	>	* there is nothing there now" rule before using them in search or
201	>	* reduce operations.
202	>	*
203	>	* <p>Methods accepting and/or returning Entry arguments maintain
204	>	* key-value associations. They may be useful for example when
205	>	* finding the key for the greatest value. Note that "plain" Entry
206	>	* arguments can be supplied using {@code new
207	>	* AbstractMap.SimpleEntry(k,v)}.
208	>	*
209	>	* <p>Bulk operations may complete abruptly, throwing an
210	>	* exception encountered in the application of a supplied
211	>	* function. Bear in mind when handling such exceptions that other
212	>	* concurrently executing functions could also have thrown
213	>	* exceptions, or would have done so if the first exception had
214	>	* not occurred.
215	>	*
216	>	* <p>Speedups for parallel compared to sequential forms are common
217	>	* but not guaranteed.  Parallel operations involving brief functions
218	>	* on small maps may execute more slowly than sequential forms if the
219	>	* underlying work to parallelize the computation is more expensive
220	>	* than the computation itself.  Similarly, parallelization may not
221	>	* lead to much actual parallelism if all processors are busy
222	>	* performing unrelated tasks.
223	>	*
224	>	* <p>All arguments to all task methods must be non-null.
225	>	*
226	>	* <p>This class is a member of the
227	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
228	>	* Java Collections Framework</a>.
229		*
230		* @since 1.5
231		* @author Doug Lea
232		* @param <K> the type of keys maintained by this map
233	<	* @param <V> the type of mapped values
233	>	* @param <V> the type of mapped values
234		*/
235	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
236	<	implements ConcurrentMap<K, V>, Cloneable, Serializable {
235	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
236	>	implements ConcurrentMap<K,V>, Serializable {
237		private static final long serialVersionUID = 7249069246763182397L;
238
239		/*
240	<	* The basic strategy is to subdivide the table among Segments,
241	<	* each of which itself is a concurrently readable hash table.
240	>	* Overview:
241	>	*
242	>	* The primary design goal of this hash table is to maintain
243	>	* concurrent readability (typically method get(), but also
244	>	* iterators and related methods) while minimizing update
245	>	* contention. Secondary goals are to keep space consumption about
246	>	* the same or better than java.util.HashMap, and to support high
247	>	* initial insertion rates on an empty table by many threads.
248	>	*
249	>	* This map usually acts as a binned (bucketed) hash table.  Each
250	>	* key-value mapping is held in a Node.  Most nodes are instances
251	>	* of the basic Node class with hash, key, value, and next
252	>	* fields. However, various subclasses exist: TreeNodes are
253	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
254	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
255	>	* of bins during resizing. ReservationNodes are used as
256	>	* placeholders while establishing values in computeIfAbsent and
257	>	* related methods.  The types TreeBin, ForwardingNode, and
258	>	* ReservationNode do not hold normal user keys, values, or
259	>	* hashes, and are readily distinguishable during search etc
260	>	* because they have negative hash fields and null key and value
261	>	* fields. (These special nodes are either uncommon or transient,
262	>	* so the impact of carrying around some unused fields is
263	>	* insignificant.)
264	>	*
265	>	* The table is lazily initialized to a power-of-two size upon the
266	>	* first insertion.  Each bin in the table normally contains a
267	>	* list of Nodes (most often, the list has only zero or one Node).
268	>	* Table accesses require volatile/atomic reads, writes, and
269	>	* CASes.  Because there is no other way to arrange this without
270	>	* adding further indirections, we use intrinsics
271	>	* (sun.misc.Unsafe) operations.
272	>	*
273	>	* We use the top (sign) bit of Node hash fields for control
274	>	* purposes -- it is available anyway because of addressing
275	>	* constraints.  Nodes with negative hash fields are specially
276	>	* handled or ignored in map methods.
277	>	*
278	>	* Insertion (via put or its variants) of the first node in an
279	>	* empty bin is performed by just CASing it to the bin.  This is
280	>	* by far the most common case for put operations under most
281	>	* key/hash distributions.  Other update operations (insert,
282	>	* delete, and replace) require locks.  We do not want to waste
283	>	* the space required to associate a distinct lock object with
284	>	* each bin, so instead use the first node of a bin list itself as
285	>	* a lock. Locking support for these locks relies on builtin
286	>	* "synchronized" monitors.
287	>	*
288	>	* Using the first node of a list as a lock does not by itself
289	>	* suffice though: When a node is locked, any update must first
290	>	* validate that it is still the first node after locking it, and
291	>	* retry if not. Because new nodes are always appended to lists,
292	>	* once a node is first in a bin, it remains first until deleted
293	>	* or the bin becomes invalidated (upon resizing).
294	>	*
295	>	* The main disadvantage of per-bin locks is that other update
296	>	* operations on other nodes in a bin list protected by the same
297	>	* lock can stall, for example when user equals() or mapping
298	>	* functions take a long time.  However, statistically, under
299	>	* random hash codes, this is not a common problem.  Ideally, the
300	>	* frequency of nodes in bins follows a Poisson distribution
301	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
302	>	* parameter of about 0.5 on average, given the resizing threshold
303	>	* of 0.75, although with a large variance because of resizing
304	>	* granularity. Ignoring variance, the expected occurrences of
305	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
306	>	* first values are:
307	>	*
308	>	* 0:    0.60653066
309	>	* 1:    0.30326533
310	>	* 2:    0.07581633
311	>	* 3:    0.01263606
312	>	* 4:    0.00157952
313	>	* 5:    0.00015795
314	>	* 6:    0.00001316
315	>	* 7:    0.00000094
316	>	* 8:    0.00000006
317	>	* more: less than 1 in ten million
318	>	*
319	>	* Lock contention probability for two threads accessing distinct
320	>	* elements is roughly 1 / (8 * #elements) under random hashes.
321	>	*
322	>	* Actual hash code distributions encountered in practice
323	>	* sometimes deviate significantly from uniform randomness.  This
324	>	* includes the case when N > (1<<30), so some keys MUST collide.
325	>	* Similarly for dumb or hostile usages in which multiple keys are
326	>	* designed to have identical hash codes or ones that differs only
327	>	* in masked-out high bits. So we use a secondary strategy that
328	>	* applies when the number of nodes in a bin exceeds a
329	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
330	>	* specialized form of red-black trees), bounding search time to
331	>	* O(log N).  Each search step in a TreeBin is at least twice as
332	>	* slow as in a regular list, but given that N cannot exceed
333	>	* (1<<64) (before running out of addresses) this bounds search
334	>	* steps, lock hold times, etc, to reasonable constants (roughly
335	>	* 100 nodes inspected per operation worst case) so long as keys
336	>	* are Comparable (which is very common -- String, Long, etc).
337	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
338	>	* traversal pointers as regular nodes, so can be traversed in
339	>	* iterators in the same way.
340	>	*
341	>	* The table is resized when occupancy exceeds a percentage
342	>	* threshold (nominally, 0.75, but see below).  Any thread
343	>	* noticing an overfull bin may assist in resizing after the
344	>	* initiating thread allocates and sets up the replacement array.
345	>	* However, rather than stalling, these other threads may proceed
346	>	* with insertions etc.  The use of TreeBins shields us from the
347	>	* worst case effects of overfilling while resizes are in
348	>	* progress.  Resizing proceeds by transferring bins, one by one,
349	>	* from the table to the next table. However, threads claim small
350	>	* blocks of indices to transfer (via field transferIndex) before
351	>	* doing so, reducing contention.  A generation stamp in field
352	>	* sizeCtl ensures that resizings do not overlap. Because we are
353	>	* using power-of-two expansion, the elements from each bin must
354	>	* either stay at same index, or move with a power of two
355	>	* offset. We eliminate unnecessary node creation by catching
356	>	* cases where old nodes can be reused because their next fields
357	>	* won't change.  On average, only about one-sixth of them need
358	>	* cloning when a table doubles. The nodes they replace will be
359	>	* garbage collectable as soon as they are no longer referenced by
360	>	* any reader thread that may be in the midst of concurrently
361	>	* traversing table.  Upon transfer, the old table bin contains
362	>	* only a special forwarding node (with hash field "MOVED") that
363	>	* contains the next table as its key. On encountering a
364	>	* forwarding node, access and update operations restart, using
365	>	* the new table.
366	>	*
367	>	* Each bin transfer requires its bin lock, which can stall
368	>	* waiting for locks while resizing. However, because other
369	>	* threads can join in and help resize rather than contend for
370	>	* locks, average aggregate waits become shorter as resizing
371	>	* progresses.  The transfer operation must also ensure that all
372	>	* accessible bins in both the old and new table are usable by any
373	>	* traversal.  This is arranged in part by proceeding from the
374	>	* last bin (table.length - 1) up towards the first.  Upon seeing
375	>	* a forwarding node, traversals (see class Traverser) arrange to
376	>	* move to the new table without revisiting nodes.  To ensure that
377	>	* no intervening nodes are skipped even when moved out of order,
378	>	* a stack (see class TableStack) is created on first encounter of
379	>	* a forwarding node during a traversal, to maintain its place if
380	>	* later processing the current table. The need for these
381	>	* save/restore mechanics is relatively rare, but when one
382	>	* forwarding node is encountered, typically many more will be.
383	>	* So Traversers use a simple caching scheme to avoid creating so
384	>	* many new TableStack nodes. (Thanks to Peter Levart for
385	>	* suggesting use of a stack here.)
386	>	*
387	>	* The traversal scheme also applies to partial traversals of
388	>	* ranges of bins (via an alternate Traverser constructor)
389	>	* to support partitioned aggregate operations.  Also, read-only
390	>	* operations give up if ever forwarded to a null table, which
391	>	* provides support for shutdown-style clearing, which is also not
392	>	* currently implemented.
393	>	*
394	>	* Lazy table initialization minimizes footprint until first use,
395	>	* and also avoids resizings when the first operation is from a
396	>	* putAll, constructor with map argument, or deserialization.
397	>	* These cases attempt to override the initial capacity settings,
398	>	* but harmlessly fail to take effect in cases of races.
399	>	*
400	>	* The element count is maintained using a specialization of
401	>	* LongAdder. We need to incorporate a specialization rather than
402	>	* just use a LongAdder in order to access implicit
403	>	* contention-sensing that leads to creation of multiple
404	>	* CounterCells.  The counter mechanics avoid contention on
405	>	* updates but can encounter cache thrashing if read too
406	>	* frequently during concurrent access. To avoid reading so often,
407	>	* resizing under contention is attempted only upon adding to a
408	>	* bin already holding two or more nodes. Under uniform hash
409	>	* distributions, the probability of this occurring at threshold
410	>	* is around 13%, meaning that only about 1 in 8 puts check
411	>	* threshold (and after resizing, many fewer do so).
412	>	*
413	>	* TreeBins use a special form of comparison for search and
414	>	* related operations (which is the main reason we cannot use
415	>	* existing collections such as TreeMaps). TreeBins contain
416	>	* Comparable elements, but may contain others, as well as
417	>	* elements that are Comparable but not necessarily Comparable for
418	>	* the same T, so we cannot invoke compareTo among them. To handle
419	>	* this, the tree is ordered primarily by hash value, then by
420	>	* Comparable.compareTo order if applicable.  On lookup at a node,
421	>	* if elements are not comparable or compare as 0 then both left
422	>	* and right children may need to be searched in the case of tied
423	>	* hash values. (This corresponds to the full list search that
424	>	* would be necessary if all elements were non-Comparable and had
425	>	* tied hashes.) On insertion, to keep a total ordering (or as
426	>	* close as is required here) across rebalancings, we compare
427	>	* classes and identityHashCodes as tie-breakers. The red-black
428	>	* balancing code is updated from pre-jdk-collections
429	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
430	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
431	>	* Algorithms" (CLR).
432	>	*
433	>	* TreeBins also require an additional locking mechanism.  While
434	>	* list traversal is always possible by readers even during
435	>	* updates, tree traversal is not, mainly because of tree-rotations
436	>	* that may change the root node and/or its linkages.  TreeBins
437	>	* include a simple read-write lock mechanism parasitic on the
438	>	* main bin-synchronization strategy: Structural adjustments
439	>	* associated with an insertion or removal are already bin-locked
440	>	* (and so cannot conflict with other writers) but must wait for
441	>	* ongoing readers to finish. Since there can be only one such
442	>	* waiter, we use a simple scheme using a single "waiter" field to
443	>	* block writers.  However, readers need never block.  If the root
444	>	* lock is held, they proceed along the slow traversal path (via
445	>	* next-pointers) until the lock becomes available or the list is
446	>	* exhausted, whichever comes first. These cases are not fast, but
447	>	* maximize aggregate expected throughput.
448	>	*
449	>	* Maintaining API and serialization compatibility with previous
450	>	* versions of this class introduces several oddities. Mainly: We
451	>	* leave untouched but unused constructor arguments referring to
452	>	* concurrencyLevel. We accept a loadFactor constructor argument,
453	>	* but apply it only to initial table capacity (which is the only
454	>	* time that we can guarantee to honor it.) We also declare an
455	>	* unused "Segment" class that is instantiated in minimal form
456	>	* only when serializing.
457	>	*
458	>	* Also, solely for compatibility with previous versions of this
459	>	* class, it extends AbstractMap, even though all of its methods
460	>	* are overridden, so it is just useless baggage.
461	>	*
462	>	* This file is organized to make things a little easier to follow
463	>	* while reading than they might otherwise: First the main static
464	>	* declarations and utilities, then fields, then main public
465	>	* methods (with a few factorings of multiple public methods into
466	>	* internal ones), then sizing methods, trees, traversers, and
467	>	* bulk operations.
468		*/
469
470		/* ---------------- Constants -------------- */
471
472		/**
473	<	* The default initial number of table slots for this table.
474	<	* Used when not otherwise specified in constructor.
473	>	* The largest possible table capacity.  This value must be
474	>	* exactly 1<<30 to stay within Java array allocation and indexing
475	>	* bounds for power of two table sizes, and is further required
476	>	* because the top two bits of 32bit hash fields are used for
477	>	* control purposes.
478		*/
479	<	private static int DEFAULT_INITIAL_CAPACITY = 16;
479	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
480	>
481	>	/**
482	>	* The default initial table capacity.  Must be a power of 2
483	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
484	>	*/
485	>	private static final int DEFAULT_CAPACITY = 16;
486	>
487	>	/**
488	>	* The largest possible (non-power of two) array size.
489	>	* Needed by toArray and related methods.
490	>	*/
491	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
492	>
493	>	/**
494	>	* The default concurrency level for this table. Unused but
495	>	* defined for compatibility with previous versions of this class.
496	>	*/
497	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
498	>
499	>	/**
500	>	* The load factor for this table. Overrides of this value in
501	>	* constructors affect only the initial table capacity.  The
502	>	* actual floating point value isn't normally used -- it is
503	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
504	>	* the associated resizing threshold.
505	>	*/
506	>	private static final float LOAD_FACTOR = 0.75f;
507	>
508	>	/**
509	>	* The bin count threshold for using a tree rather than list for a
510	>	* bin.  Bins are converted to trees when adding an element to a
511	>	* bin with at least this many nodes. The value must be greater
512	>	* than 2, and should be at least 8 to mesh with assumptions in
513	>	* tree removal about conversion back to plain bins upon
514	>	* shrinkage.
515	>	*/
516	>	static final int TREEIFY_THRESHOLD = 8;
517	>
518	>	/**
519	>	* The bin count threshold for untreeifying a (split) bin during a
520	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
521	>	* most 6 to mesh with shrinkage detection under removal.
522	>	*/
523	>	static final int UNTREEIFY_THRESHOLD = 6;
524	>
525	>	/**
526	>	* The smallest table capacity for which bins may be treeified.
527	>	* (Otherwise the table is resized if too many nodes in a bin.)
528	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
529	>	* conflicts between resizing and treeification thresholds.
530	>	*/
531	>	static final int MIN_TREEIFY_CAPACITY = 64;
532	>
533	>	/**
534	>	* Minimum number of rebinnings per transfer step. Ranges are
535	>	* subdivided to allow multiple resizer threads.  This value
536	>	* serves as a lower bound to avoid resizers encountering
537	>	* excessive memory contention.  The value should be at least
538	>	* DEFAULT_CAPACITY.
539	>	*/
540	>	private static final int MIN_TRANSFER_STRIDE = 16;
541	>
542	>	/**
543	>	* The number of bits used for generation stamp in sizeCtl.
544	>	* Must be at least 6 for 32bit arrays.
545	>	*/
546	>	private static int RESIZE_STAMP_BITS = 16;
547	>
548	>	/**
549	>	* The maximum number of threads that can help resize.
550	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
551	>	*/
552	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
553	>
554	>	/**
555	>	* The bit shift for recording size stamp in sizeCtl.
556	>	*/
557	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
558	>
559	>	/*
560	>	* Encodings for Node hash fields. See above for explanation.
561	>	*/
562	>	static final int MOVED     = -1; // hash for forwarding nodes
563	>	static final int TREEBIN   = -2; // hash for roots of trees
564	>	static final int RESERVED  = -3; // hash for transient reservations
565	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
566	>
567	>	/** Number of CPUS, to place bounds on some sizings */
568	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
569	>
570	>	/** For serialization compatibility. */
571	>	private static final ObjectStreamField[] serialPersistentFields = {
572	>	new ObjectStreamField("segments", Segment[].class),
573	>	new ObjectStreamField("segmentMask", Integer.TYPE),
574	>	new ObjectStreamField("segmentShift", Integer.TYPE)
575	>	};
576	>
577	>	/* ---------------- Nodes -------------- */
578	>
579	>	/**
580	>	* Key-value entry.  This class is never exported out as a
581	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
582	>	* MapEntry below), but can be used for read-only traversals used
583	>	* in bulk tasks.  Subclasses of Node with a negative hash field
584	>	* are special, and contain null keys and values (but are never
585	>	* exported).  Otherwise, keys and vals are never null.
586	>	*/
587	>	static class Node<K,V> implements Map.Entry<K,V> {
588	>	final int hash;
589	>	final K key;
590	>	volatile V val;
591	>	volatile Node<K,V> next;
592	>
593	>	Node(int hash, K key, V val, Node<K,V> next) {
594	>	this.hash = hash;
595	>	this.key = key;
596	>	this.val = val;
597	>	this.next = next;
598	>	}
599	>
600	>	public final K getKey()     { return key; }
601	>	public final V getValue()   { return val; }
602	>	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
603	>	public final String toString() {
604	>	return Helpers.mapEntryToString(key, val);
605	>	}
606	>	public final V setValue(V value) {
607	>	throw new UnsupportedOperationException();
608	>	}
609	>
610	>	public final boolean equals(Object o) {
611	>	Object k, v, u; Map.Entry<?,?> e;
612	>	return ((o instanceof Map.Entry) &&
613	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
614	>	(v = e.getValue()) != null &&
615	>	(k == key || k.equals(key)) &&
616	>	(v == (u = val) || v.equals(u)));
617	>	}
618	>
619	>	/**
620	>	* Virtualized support for map.get(); overridden in subclasses.
621	>	*/
622	>	Node<K,V> find(int h, Object k) {
623	>	Node<K,V> e = this;
624	>	if (k != null) {
625	>	do {
626	>	K ek;
627	>	if (e.hash == h &&
628	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
629	>	return e;
630	>	} while ((e = e.next) != null);
631	>	}
632	>	return null;
633	>	}
634	>	}
635	>
636	>	/* ---------------- Static utilities -------------- */
637
638		/**
639	<	* The maximum capacity, used if a higher value is implicitly
640	<	* specified by either of the constructors with arguments.  MUST
641	<	* be a power of two <= 1<<30 to ensure that entries are indexible
642	<	* using ints.
639	>	* Spreads (XORs) higher bits of hash to lower and also forces top
640	>	* bit to 0. Because the table uses power-of-two masking, sets of
641	>	* hashes that vary only in bits above the current mask will
642	>	* always collide. (Among known examples are sets of Float keys
643	>	* holding consecutive whole numbers in small tables.)  So we
644	>	* apply a transform that spreads the impact of higher bits
645	>	* downward. There is a tradeoff between speed, utility, and
646	>	* quality of bit-spreading. Because many common sets of hashes
647	>	* are already reasonably distributed (so don't benefit from
648	>	* spreading), and because we use trees to handle large sets of
649	>	* collisions in bins, we just XOR some shifted bits in the
650	>	* cheapest possible way to reduce systematic lossage, as well as
651	>	* to incorporate impact of the highest bits that would otherwise
652	>	* never be used in index calculations because of table bounds.
653		*/
654	<	static final int MAXIMUM_CAPACITY = 1 << 30;
654	>	static final int spread(int h) {
655	>	return (h ^ (h >>> 16)) & HASH_BITS;
656	>	}
657
658		/**
659	<	* The default load factor for this table.  Used when not
660	<	* otherwise specified in constructor.
659	>	* Returns a power of two table size for the given desired capacity.
660	>	* See Hackers Delight, sec 3.2
661		*/
662	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
662	>	private static final int tableSizeFor(int c) {
663	>	int n = c - 1;
664	>	n |= n >>> 1;
665	>	n |= n >>> 2;
666	>	n |= n >>> 4;
667	>	n |= n >>> 8;
668	>	n |= n >>> 16;
669	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
670	>	}
671
672		/**
673	<	* The default number of concurrency control segments.
674	<	**/
675	<	private static final int DEFAULT_SEGMENTS = 16;
673	>	* Returns x's Class if it is of the form "class C implements
674	>	* Comparable<C>", else null.
675	>	*/
676	>	static Class<?> comparableClassFor(Object x) {
677	>	if (x instanceof Comparable) {
678	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
679	>	if ((c = x.getClass()) == String.class) // bypass checks
680	>	return c;
681	>	if ((ts = c.getGenericInterfaces()) != null) {
682	>	for (int i = 0; i < ts.length; ++i) {
683	>	if (((t = ts[i]) instanceof ParameterizedType) &&
684	>	((p = (ParameterizedType)t).getRawType() ==
685	>	Comparable.class) &&
686	>	(as = p.getActualTypeArguments()) != null &&
687	>	as.length == 1 && as[0] == c) // type arg is c
688	>	return c;
689	>	}
690	>	}
691	>	}
692	>	return null;
693	>	}
694
695		/**
696	<	* The maximum number of segments to allow; used to bound ctor arguments.
696	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
697	>	* class), else 0.
698		*/
699	<	private static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
699	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
700	>	static int compareComparables(Class<?> kc, Object k, Object x) {
701	>	return (x == null || x.getClass() != kc ? 0 :
702	>	((Comparable)k).compareTo(x));
703	>	}
704	>
705	>	/* ---------------- Table element access -------------- */
706	>
707	>	/*
708	>	* Volatile access methods are used for table elements as well as
709	>	* elements of in-progress next table while resizing.  All uses of
710	>	* the tab arguments must be null checked by callers.  All callers
711	>	* also paranoically precheck that tab's length is not zero (or an
712	>	* equivalent check), thus ensuring that any index argument taking
713	>	* the form of a hash value anded with (length - 1) is a valid
714	>	* index.  Note that, to be correct wrt arbitrary concurrency
715	>	* errors by users, these checks must operate on local variables,
716	>	* which accounts for some odd-looking inline assignments below.
717	>	* Note that calls to setTabAt always occur within locked regions,
718	>	* and so in principle require only release ordering, not
719	>	* full volatile semantics, but are currently coded as volatile
720	>	* writes to be conservative.
721	>	*/
722	>
723	>	@SuppressWarnings("unchecked")
724	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
725	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
726	>	}
727	>
728	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
729	>	Node<K,V> c, Node<K,V> v) {
730	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
731	>	}
732	>
733	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
734	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
735	>	}
736
737		/* ---------------- Fields -------------- */
738
739		/**
740	<	* Mask value for indexing into segments. The upper bits of a
741	<	* key's hash code are used to choose the segment.
742	<	**/
743	<	private final int segmentMask;
740	>	* The array of bins. Lazily initialized upon first insertion.
741	>	* Size is always a power of two. Accessed directly by iterators.
742	>	*/
743	>	transient volatile Node<K,V>[] table;
744
745		/**
746	<	* Shift value for indexing within segments.
747	<	**/
748	<	private final int segmentShift;
746	>	* The next table to use; non-null only while resizing.
747	>	*/
748	>	private transient volatile Node<K,V>[] nextTable;
749
750		/**
751	<	* The segments, each of which is a specialized hash table
751	>	* Base counter value, used mainly when there is no contention,
752	>	* but also as a fallback during table initialization
753	>	* races. Updated via CAS.
754		*/
755	<	private final Segment[] segments;
755	>	private transient volatile long baseCount;
756
757	<	private transient Set<K> keySet;
758	<	private transient Set<Map.Entry<K,V>> entrySet;
759	<	private transient Collection<V> values;
757	>	/**
758	>	* Table initialization and resizing control.  When negative, the
759	>	* table is being initialized or resized: -1 for initialization,
760	>	* else -(1 + the number of active resizing threads).  Otherwise,
761	>	* when table is null, holds the initial table size to use upon
762	>	* creation, or 0 for default. After initialization, holds the
763	>	* next element count value upon which to resize the table.
764	>	*/
765	>	private transient volatile int sizeCtl;
766
767	<	/* ---------------- Small Utilities -------------- */
767	>	/**
768	>	* The next table index (plus one) to split while resizing.
769	>	*/
770	>	private transient volatile int transferIndex;
771
772		/**
773	<	* Return a hash code for non-null Object x.
134	<	* Uses the same hash code spreader as most other j.u hash tables.
135	<	* @param x the object serving as a key
136	<	* @return the hash code
773	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
774		*/
775	<	private static int hash(Object x) {
776	<	int h = x.hashCode();
777	<	h += ~(h << 9);
778	<	h ^=  (h >>> 14);
779	<	h +=  (h << 4);
780	<	h ^=  (h >>> 10);
781	<	return h;
775	>	private transient volatile int cellsBusy;
776	>
777	>	/**
778	>	* Table of counter cells. When non-null, size is a power of 2.
779	>	*/
780	>	private transient volatile CounterCell[] counterCells;
781	>
782	>	// views
783	>	private transient KeySetView<K,V> keySet;
784	>	private transient ValuesView<K,V> values;
785	>	private transient EntrySetView<K,V> entrySet;
786	>
787	>
788	>	/* ---------------- Public operations -------------- */
789	>
790	>	/**
791	>	* Creates a new, empty map with the default initial table size (16).
792	>	*/
793	>	public ConcurrentHashMap() {
794		}
795
796		/**
797	<	* Return the segment that should be used for key with given hash
797	>	* Creates a new, empty map with an initial table size
798	>	* accommodating the specified number of elements without the need
799	>	* to dynamically resize.
800	>	*
801	>	* @param initialCapacity The implementation performs internal
802	>	* sizing to accommodate this many elements.
803	>	* @throws IllegalArgumentException if the initial capacity of
804	>	* elements is negative
805		*/
806	<	private Segment<K,V> segmentFor(int hash) {
807	<	return (Segment<K,V>) segments[(hash >>> segmentShift) & segmentMask];
806	>	public ConcurrentHashMap(int initialCapacity) {
807	>	if (initialCapacity < 0)
808	>	throw new IllegalArgumentException();
809	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
810	>	MAXIMUM_CAPACITY :
811	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
812	>	this.sizeCtl = cap;
813		}
814
815	<	/* ---------------- Inner Classes -------------- */
815	>	/**
816	>	* Creates a new map with the same mappings as the given map.
817	>	*
818	>	* @param m the map
819	>	*/
820	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
821	>	this.sizeCtl = DEFAULT_CAPACITY;
822	>	putAll(m);
823	>	}
824
825		/**
826	<	* Segments are specialized versions of hash tables.  This
827	<	* subclasses from ReentrantLock opportunistically, just to
828	<	* simplify some locking and avoid separate construction.
829	<	**/
830	<	private static final class Segment<K,V> extends ReentrantLock implements Serializable {
831	<	/*
832	<	* Segments maintain a table of entry lists that are ALWAYS
833	<	* kept in a consistent state, so can be read without locking.
834	<	* Next fields of nodes are immutable (final).  All list
835	<	* additions are performed at the front of each bin. This
836	<	* makes it easy to check changes, and also fast to traverse.
837	<	* When nodes would otherwise be changed, new nodes are
838	<	* created to replace them. This works well for hash tables
839	<	* since the bin lists tend to be short. (The average length
840	<	* is less than two for the default load factor threshold.)
841	<	*
842	<	* Read operations can thus proceed without locking, but rely
174	<	* on a memory barrier to ensure that completed write
175	<	* operations performed by other threads are
176	<	* noticed. Conveniently, the "count" field, tracking the
177	<	* number of elements, can also serve as the volatile variable
178	<	* providing proper read/write barriers. This is convenient
179	<	* because this field needs to be read in many read operations
180	<	* anyway.
181	<	*
182	<	* Implementors note. The basic rules for all this are:
183	<	*
184	<	*   - All unsynchronized read operations must first read the
185	<	*     "count" field, and should not look at table entries if
186	<	*     it is 0.
187	<	*
188	<	*   - All synchronized write operations should write to
189	<	*     the "count" field after updating. The operations must not
190	<	*     take any action that could even momentarily cause
191	<	*     a concurrent read operation to see inconsistent
192	<	*     data. This is made easier by the nature of the read
193	<	*     operations in Map. For example, no operation
194	<	*     can reveal that the table has grown but the threshold
195	<	*     has not yet been updated, so there are no atomicity
196	<	*     requirements for this with respect to reads.
197	<	*
198	<	* As a guide, all critical volatile reads and writes are marked
199	<	* in code comments.
200	<	*/
826	>	* Creates a new, empty map with an initial table size based on
827	>	* the given number of elements ({@code initialCapacity}) and
828	>	* initial table density ({@code loadFactor}).
829	>	*
830	>	* @param initialCapacity the initial capacity. The implementation
831	>	* performs internal sizing to accommodate this many elements,
832	>	* given the specified load factor.
833	>	* @param loadFactor the load factor (table density) for
834	>	* establishing the initial table size
835	>	* @throws IllegalArgumentException if the initial capacity of
836	>	* elements is negative or the load factor is nonpositive
837	>	*
838	>	* @since 1.6
839	>	*/
840	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
841	>	this(initialCapacity, loadFactor, 1);
842	>	}
843
844	<	private static final long serialVersionUID = 2249069246763182397L;
844	>	/**
845	>	* Creates a new, empty map with an initial table size based on
846	>	* the given number of elements ({@code initialCapacity}), table
847	>	* density ({@code loadFactor}), and number of concurrently
848	>	* updating threads ({@code concurrencyLevel}).
849	>	*
850	>	* @param initialCapacity the initial capacity. The implementation
851	>	* performs internal sizing to accommodate this many elements,
852	>	* given the specified load factor.
853	>	* @param loadFactor the load factor (table density) for
854	>	* establishing the initial table size
855	>	* @param concurrencyLevel the estimated number of concurrently
856	>	* updating threads. The implementation may use this value as
857	>	* a sizing hint.
858	>	* @throws IllegalArgumentException if the initial capacity is
859	>	* negative or the load factor or concurrencyLevel are
860	>	* nonpositive
861	>	*/
862	>	public ConcurrentHashMap(int initialCapacity,
863	>	float loadFactor, int concurrencyLevel) {
864	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
865	>	throw new IllegalArgumentException();
866	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
867	>	initialCapacity = concurrencyLevel;   // as estimated threads
868	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
869	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
870	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
871	>	this.sizeCtl = cap;
872	>	}
873
874	<	/**
205	<	* The number of elements in this segment's region.
206	<	**/
207	<	transient volatile int count;
874	>	// Original (since JDK1.2) Map methods
875
876	<	/**
877	<	* Number of updates; used for checking lack of modifications
878	<	* in bulk-read methods.
879	<	*/
880	<	transient int modCount;
876	>	/**
877	>	* {@inheritDoc}
878	>	*/
879	>	public int size() {
880	>	long n = sumCount();
881	>	return ((n < 0L) ? 0 :
882	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
883	>	(int)n);
884	>	}
885
886	<	/**
887	<	* The table is rehashed when its size exceeds this threshold.
888	<	* (The value of this field is always (int)(capacity *
889	<	* loadFactor).)
890	<	*/
891	<	private transient int threshold;
886	>	/**
887	>	* {@inheritDoc}
888	>	*/
889	>	public boolean isEmpty() {
890	>	return sumCount() <= 0L; // ignore transient negative values
891	>	}
892
893	<	/**
894	<	* The per-segment table
895	<	*/
896	<	transient HashEntry[] table;
893	>	/**
894	>	* Returns the value to which the specified key is mapped,
895	>	* or {@code null} if this map contains no mapping for the key.
896	>	*
897	>	* <p>More formally, if this map contains a mapping from a key
898	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
899	>	* then this method returns {@code v}; otherwise it returns
900	>	* {@code null}.  (There can be at most one such mapping.)
901	>	*
902	>	* @throws NullPointerException if the specified key is null
903	>	*/
904	>	public V get(Object key) {
905	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
906	>	int h = spread(key.hashCode());
907	>	if ((tab = table) != null && (n = tab.length) > 0 &&
908	>	(e = tabAt(tab, (n - 1) & h)) != null) {
909	>	if ((eh = e.hash) == h) {
910	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
911	>	return e.val;
912	>	}
913	>	else if (eh < 0)
914	>	return (p = e.find(h, key)) != null ? p.val : null;
915	>	while ((e = e.next) != null) {
916	>	if (e.hash == h &&
917	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
918	>	return e.val;
919	>	}
920	>	}
921	>	return null;
922	>	}
923
924	<	/**
925	<	* The load factor for the hash table.  Even though this value
926	<	* is same for all segments, it is replicated to avoid needing
927	<	* links to outer object.
928	<	* @serial
929	<	*/
930	<	private final float loadFactor;
924	>	/**
925	>	* Tests if the specified object is a key in this table.
926	>	*
927	>	* @param  key possible key
928	>	* @return {@code true} if and only if the specified object
929	>	*         is a key in this table, as determined by the
930	>	*         {@code equals} method; {@code false} otherwise
931	>	* @throws NullPointerException if the specified key is null
932	>	*/
933	>	public boolean containsKey(Object key) {
934	>	return get(key) != null;
935	>	}
936
937	<	Segment(int initialCapacity, float lf) {
938	<	loadFactor = lf;
939	<	setTable(new HashEntry[initialCapacity]);
937	>	/**
938	>	* Returns {@code true} if this map maps one or more keys to the
939	>	* specified value. Note: This method may require a full traversal
940	>	* of the map, and is much slower than method {@code containsKey}.
941	>	*
942	>	* @param value value whose presence in this map is to be tested
943	>	* @return {@code true} if this map maps one or more keys to the
944	>	*         specified value
945	>	* @throws NullPointerException if the specified value is null
946	>	*/
947	>	public boolean containsValue(Object value) {
948	>	if (value == null)
949	>	throw new NullPointerException();
950	>	Node<K,V>[] t;
951	>	if ((t = table) != null) {
952	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
953	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
954	>	V v;
955	>	if ((v = p.val) == value || (v != null && value.equals(v)))
956	>	return true;
957	>	}
958		}
959	+	return false;
960	+	}
961
962	<	/**
963	<	* Set table to new HashEntry array.
964	<	* Call only while holding lock or in constructor.
965	<	**/
966	<	private void setTable(HashEntry[] newTable) {
967	<	table = newTable;
968	<	threshold = (int)(newTable.length * loadFactor);
969	<	count = count; // write-volatile
962	>	/**
963	>	* Maps the specified key to the specified value in this table.
964	>	* Neither the key nor the value can be null.
965	>	*
966	>	* <p>The value can be retrieved by calling the {@code get} method
967	>	* with a key that is equal to the original key.
968	>	*
969	>	* @param key key with which the specified value is to be associated
970	>	* @param value value to be associated with the specified key
971	>	* @return the previous value associated with {@code key}, or
972	>	*         {@code null} if there was no mapping for {@code key}
973	>	* @throws NullPointerException if the specified key or value is null
974	>	*/
975	>	public V put(K key, V value) {
976	>	return putVal(key, value, false);
977	>	}
978	>
979	>	/** Implementation for put and putIfAbsent */
980	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
981	>	if (key == null || value == null) throw new NullPointerException();
982	>	int hash = spread(key.hashCode());
983	>	int binCount = 0;
984	>	for (Node<K,V>[] tab = table;;) {
985	>	Node<K,V> f; int n, i, fh;
986	>	if (tab == null || (n = tab.length) == 0)
987	>	tab = initTable();
988	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
989	>	if (casTabAt(tab, i, null,
990	>	new Node<K,V>(hash, key, value, null)))
991	>	break;                   // no lock when adding to empty bin
992	>	}
993	>	else if ((fh = f.hash) == MOVED)
994	>	tab = helpTransfer(tab, f);
995	>	else {
996	>	V oldVal = null;
997	>	synchronized (f) {
998	>	if (tabAt(tab, i) == f) {
999	>	if (fh >= 0) {
1000	>	binCount = 1;
1001	>	for (Node<K,V> e = f;; ++binCount) {
1002	>	K ek;
1003	>	if (e.hash == hash &&
1004	>	((ek = e.key) == key ||
1005	>	(ek != null && key.equals(ek)))) {
1006	>	oldVal = e.val;
1007	>	if (!onlyIfAbsent)
1008	>	e.val = value;
1009	>	break;
1010	>	}
1011	>	Node<K,V> pred = e;
1012	>	if ((e = e.next) == null) {
1013	>	pred.next = new Node<K,V>(hash, key,
1014	>	value, null);
1015	>	break;
1016	>	}
1017	>	}
1018	>	}
1019	>	else if (f instanceof TreeBin) {
1020	>	Node<K,V> p;
1021	>	binCount = 2;
1022	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1023	>	value)) != null) {
1024	>	oldVal = p.val;
1025	>	if (!onlyIfAbsent)
1026	>	p.val = value;
1027	>	}
1028	>	}
1029	>	else if (f instanceof ReservationNode)
1030	>	throw new IllegalStateException("Recursive update");
1031	>	}
1032	>	}
1033	>	if (binCount != 0) {
1034	>	if (binCount >= TREEIFY_THRESHOLD)
1035	>	treeifyBin(tab, i);
1036	>	if (oldVal != null)
1037	>	return oldVal;
1038	>	break;
1039	>	}
1040	>	}
1041		}
1042	+	addCount(1L, binCount);
1043	+	return null;
1044	+	}
1045
1046	<	/* Specialized implementations of map methods */
1046	>	/**
1047	>	* Copies all of the mappings from the specified map to this one.
1048	>	* These mappings replace any mappings that this map had for any of the
1049	>	* keys currently in the specified map.
1050	>	*
1051	>	* @param m mappings to be stored in this map
1052	>	*/
1053	>	public void putAll(Map<? extends K, ? extends V> m) {
1054	>	tryPresize(m.size());
1055	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1056	>	putVal(e.getKey(), e.getValue(), false);
1057	>	}
1058
1059	<	V get(Object key, int hash) {
1060	<	if (count != 0) { // read-volatile
1061	<	HashEntry[] tab = table;
1062	<	int index = hash & (tab.length - 1);
1063	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
1064	<	while (e != null) {
1065	<	if (e.hash == hash && key.equals(e.key))
1066	<	return e.value;
1067	<	e = e.next;
1059	>	/**
1060	>	* Removes the key (and its corresponding value) from this map.
1061	>	* This method does nothing if the key is not in the map.
1062	>	*
1063	>	* @param  key the key that needs to be removed
1064	>	* @return the previous value associated with {@code key}, or
1065	>	*         {@code null} if there was no mapping for {@code key}
1066	>	* @throws NullPointerException if the specified key is null
1067	>	*/
1068	>	public V remove(Object key) {
1069	>	return replaceNode(key, null, null);
1070	>	}
1071	>
1072	>	/**
1073	>	* Implementation for the four public remove/replace methods:
1074	>	* Replaces node value with v, conditional upon match of cv if
1075	>	* non-null.  If resulting value is null, delete.
1076	>	*/
1077	>	final V replaceNode(Object key, V value, Object cv) {
1078	>	int hash = spread(key.hashCode());
1079	>	for (Node<K,V>[] tab = table;;) {
1080	>	Node<K,V> f; int n, i, fh;
1081	>	if (tab == null || (n = tab.length) == 0 ||
1082	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1083	>	break;
1084	>	else if ((fh = f.hash) == MOVED)
1085	>	tab = helpTransfer(tab, f);
1086	>	else {
1087	>	V oldVal = null;
1088	>	boolean validated = false;
1089	>	synchronized (f) {
1090	>	if (tabAt(tab, i) == f) {
1091	>	if (fh >= 0) {
1092	>	validated = true;
1093	>	for (Node<K,V> e = f, pred = null;;) {
1094	>	K ek;
1095	>	if (e.hash == hash &&
1096	>	((ek = e.key) == key ||
1097	>	(ek != null && key.equals(ek)))) {
1098	>	V ev = e.val;
1099	>	if (cv == null || cv == ev ||
1100	>	(ev != null && cv.equals(ev))) {
1101	>	oldVal = ev;
1102	>	if (value != null)
1103	>	e.val = value;
1104	>	else if (pred != null)
1105	>	pred.next = e.next;
1106	>	else
1107	>	setTabAt(tab, i, e.next);
1108	>	}
1109	>	break;
1110	>	}
1111	>	pred = e;
1112	>	if ((e = e.next) == null)
1113	>	break;
1114	>	}
1115	>	}
1116	>	else if (f instanceof TreeBin) {
1117	>	validated = true;
1118	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1119	>	TreeNode<K,V> r, p;
1120	>	if ((r = t.root) != null &&
1121	>	(p = r.findTreeNode(hash, key, null)) != null) {
1122	>	V pv = p.val;
1123	>	if (cv == null || cv == pv ||
1124	>	(pv != null && cv.equals(pv))) {
1125	>	oldVal = pv;
1126	>	if (value != null)
1127	>	p.val = value;
1128	>	else if (t.removeTreeNode(p))
1129	>	setTabAt(tab, i, untreeify(t.first));
1130	>	}
1131	>	}
1132	>	}
1133	>	else if (f instanceof ReservationNode)
1134	>	throw new IllegalStateException("Recursive update");
1135	>	}
1136	>	}
1137	>	if (validated) {
1138	>	if (oldVal != null) {
1139	>	if (value == null)
1140	>	addCount(-1L, -1);
1141	>	return oldVal;
1142	>	}
1143	>	break;
1144		}
1145		}
263	–	return null;
1146		}
1147	+	return null;
1148	+	}
1149
1150	<	boolean containsKey(Object key, int hash) {
1151	<	if (count != 0) { // read-volatile
1152	<	HashEntry[] tab = table;
1153	<	int index = hash & (tab.length - 1);
1154	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
1155	<	while (e != null) {
1156	<	if (e.hash == hash && key.equals(e.key))
1157	<	return true;
1158	<	e = e.next;
1150	>	/**
1151	>	* Removes all of the mappings from this map.
1152	>	*/
1153	>	public void clear() {
1154	>	long delta = 0L; // negative number of deletions
1155	>	int i = 0;
1156	>	Node<K,V>[] tab = table;
1157	>	while (tab != null && i < tab.length) {
1158	>	int fh;
1159	>	Node<K,V> f = tabAt(tab, i);
1160	>	if (f == null)
1161	>	++i;
1162	>	else if ((fh = f.hash) == MOVED) {
1163	>	tab = helpTransfer(tab, f);
1164	>	i = 0; // restart
1165	>	}
1166	>	else {
1167	>	synchronized (f) {
1168	>	if (tabAt(tab, i) == f) {
1169	>	Node<K,V> p = (fh >= 0 ? f :
1170	>	(f instanceof TreeBin) ?
1171	>	((TreeBin<K,V>)f).first : null);
1172	>	while (p != null) {
1173	>	--delta;
1174	>	p = p.next;
1175	>	}
1176	>	setTabAt(tab, i++, null);
1177	>	}
1178		}
1179		}
277	–	return false;
1180		}
1181	+	if (delta != 0L)
1182	+	addCount(delta, -1);
1183	+	}
1184	+
1185	+	/**
1186	+	* Returns a {@link Set} view of the keys contained in this map.
1187	+	* The set is backed by the map, so changes to the map are
1188	+	* reflected in the set, and vice-versa. The set supports element
1189	+	* removal, which removes the corresponding mapping from this map,
1190	+	* via the {@code Iterator.remove}, {@code Set.remove},
1191	+	* {@code removeAll}, {@code retainAll}, and {@code clear}
1192	+	* operations.  It does not support the {@code add} or
1193	+	* {@code addAll} operations.
1194	+	*
1195	+	* <p>The view's iterators and spliterators are
1196	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1197	+	*
1198	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1199	+	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1200	+	*
1201	+	* @return the set view
1202	+	*/
1203	+	public KeySetView<K,V> keySet() {
1204	+	KeySetView<K,V> ks;
1205	+	return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1206	+	}
1207
1208	<	boolean containsValue(Object value) {
1209	<	if (count != 0) { // read-volatile
1210	<	HashEntry[] tab = table;
1211	<	int len = tab.length;
1212	<	for (int i = 0 ; i < len; i++)
1213	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i] ; e != null ; e = e.next)
1214	<	if (value.equals(e.value))
1215	<	return true;
1208	>	/**
1209	>	* Returns a {@link Collection} view of the values contained in this map.
1210	>	* The collection is backed by the map, so changes to the map are
1211	>	* reflected in the collection, and vice-versa.  The collection
1212	>	* supports element removal, which removes the corresponding
1213	>	* mapping from this map, via the {@code Iterator.remove},
1214	>	* {@code Collection.remove}, {@code removeAll},
1215	>	* {@code retainAll}, and {@code clear} operations.  It does not
1216	>	* support the {@code add} or {@code addAll} operations.
1217	>	*
1218	>	* <p>The view's iterators and spliterators are
1219	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1220	>	*
1221	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1222	>	* and {@link Spliterator#NONNULL}.
1223	>	*
1224	>	* @return the collection view
1225	>	*/
1226	>	public Collection<V> values() {
1227	>	ValuesView<K,V> vs;
1228	>	return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1229	>	}
1230	>
1231	>	/**
1232	>	* Returns a {@link Set} view of the mappings contained in this map.
1233	>	* The set is backed by the map, so changes to the map are
1234	>	* reflected in the set, and vice-versa.  The set supports element
1235	>	* removal, which removes the corresponding mapping from the map,
1236	>	* via the {@code Iterator.remove}, {@code Set.remove},
1237	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1238	>	* operations.
1239	>	*
1240	>	* <p>The view's iterators and spliterators are
1241	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1242	>	*
1243	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1244	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1245	>	*
1246	>	* @return the set view
1247	>	*/
1248	>	public Set<Map.Entry<K,V>> entrySet() {
1249	>	EntrySetView<K,V> es;
1250	>	return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1251	>	}
1252	>
1253	>	/**
1254	>	* Returns the hash code value for this {@link Map}, i.e.,
1255	>	* the sum of, for each key-value pair in the map,
1256	>	* {@code key.hashCode() ^ value.hashCode()}.
1257	>	*
1258	>	* @return the hash code value for this map
1259	>	*/
1260	>	public int hashCode() {
1261	>	int h = 0;
1262	>	Node<K,V>[] t;
1263	>	if ((t = table) != null) {
1264	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1265	>	for (Node<K,V> p; (p = it.advance()) != null; )
1266	>	h += p.key.hashCode() ^ p.val.hashCode();
1267	>	}
1268	>	return h;
1269	>	}
1270	>
1271	>	/**
1272	>	* Returns a string representation of this map.  The string
1273	>	* representation consists of a list of key-value mappings (in no
1274	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1275	>	* mappings are separated by the characters {@code ", "} (comma
1276	>	* and space).  Each key-value mapping is rendered as the key
1277	>	* followed by an equals sign ("{@code =}") followed by the
1278	>	* associated value.
1279	>	*
1280	>	* @return a string representation of this map
1281	>	*/
1282	>	public String toString() {
1283	>	Node<K,V>[] t;
1284	>	int f = (t = table) == null ? 0 : t.length;
1285	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1286	>	StringBuilder sb = new StringBuilder();
1287	>	sb.append('{');
1288	>	Node<K,V> p;
1289	>	if ((p = it.advance()) != null) {
1290	>	for (;;) {
1291	>	K k = p.key;
1292	>	V v = p.val;
1293	>	sb.append(k == this ? "(this Map)" : k);
1294	>	sb.append('=');
1295	>	sb.append(v == this ? "(this Map)" : v);
1296	>	if ((p = it.advance()) == null)
1297	>	break;
1298	>	sb.append(',').append(' ');
1299		}
289	–	return false;
1300		}
1301	+	return sb.append('}').toString();
1302	+	}
1303
1304	<	boolean replace(K key, int hash, V oldValue, V newValue) {
1305	<	lock();
1306	<	try {
1307	<	int c = count;
1308	<	HashEntry[] tab = table;
1309	<	int index = hash & (tab.length - 1);
1310	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1311	<	HashEntry<K,V> e = first;
1312	<	for (;;) {
1313	<	if (e == null)
1314	<	return false;
1315	<	if (e.hash == hash && key.equals(e.key))
1316	<	break;
1317	<	e = e.next;
1304	>	/**
1305	>	* Compares the specified object with this map for equality.
1306	>	* Returns {@code true} if the given object is a map with the same
1307	>	* mappings as this map.  This operation may return misleading
1308	>	* results if either map is concurrently modified during execution
1309	>	* of this method.
1310	>	*
1311	>	* @param o object to be compared for equality with this map
1312	>	* @return {@code true} if the specified object is equal to this map
1313	>	*/
1314	>	public boolean equals(Object o) {
1315	>	if (o != this) {
1316	>	if (!(o instanceof Map))
1317	>	return false;
1318	>	Map<?,?> m = (Map<?,?>) o;
1319	>	Node<K,V>[] t;
1320	>	int f = (t = table) == null ? 0 : t.length;
1321	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1322	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1323	>	V val = p.val;
1324	>	Object v = m.get(p.key);
1325	>	if (v == null || (v != val && !v.equals(val)))
1326	>	return false;
1327	>	}
1328	>	for (Map.Entry<?,?> e : m.entrySet()) {
1329	>	Object mk, mv, v;
1330	>	if ((mk = e.getKey()) == null ||
1331	>	(mv = e.getValue()) == null ||
1332	>	(v = get(mk)) == null ||
1333	>	(mv != v && !mv.equals(v)))
1334	>	return false;
1335	>	}
1336	>	}
1337	>	return true;
1338	>	}
1339	>
1340	>	/**
1341	>	* Stripped-down version of helper class used in previous version,
1342	>	* declared for the sake of serialization compatibility
1343	>	*/
1344	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1345	>	private static final long serialVersionUID = 2249069246763182397L;
1346	>	final float loadFactor;
1347	>	Segment(float lf) { this.loadFactor = lf; }
1348	>	}
1349	>
1350	>	/**
1351	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1352	>	* stream (i.e., serializes it).
1353	>	* @param s the stream
1354	>	* @throws java.io.IOException if an I/O error occurs
1355	>	* @serialData
1356	>	* the key (Object) and value (Object)
1357	>	* for each key-value mapping, followed by a null pair.
1358	>	* The key-value mappings are emitted in no particular order.
1359	>	*/
1360	>	private void writeObject(java.io.ObjectOutputStream s)
1361	>	throws java.io.IOException {
1362	>	// For serialization compatibility
1363	>	// Emulate segment calculation from previous version of this class
1364	>	int sshift = 0;
1365	>	int ssize = 1;
1366	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1367	>	++sshift;
1368	>	ssize <<= 1;
1369	>	}
1370	>	int segmentShift = 32 - sshift;
1371	>	int segmentMask = ssize - 1;
1372	>	@SuppressWarnings("unchecked")
1373	>	Segment<K,V>[] segments = (Segment<K,V>[])
1374	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1375	>	for (int i = 0; i < segments.length; ++i)
1376	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1377	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1378	>	streamFields.put("segments", segments);
1379	>	streamFields.put("segmentShift", segmentShift);
1380	>	streamFields.put("segmentMask", segmentMask);
1381	>	s.writeFields();
1382	>
1383	>	Node<K,V>[] t;
1384	>	if ((t = table) != null) {
1385	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1386	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1387	>	s.writeObject(p.key);
1388	>	s.writeObject(p.val);
1389	>	}
1390	>	}
1391	>	s.writeObject(null);
1392	>	s.writeObject(null);
1393	>	segments = null; // throw away
1394	>	}
1395	>
1396	>	/**
1397	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1398	>	* @param s the stream
1399	>	* @throws ClassNotFoundException if the class of a serialized object
1400	>	*         could not be found
1401	>	* @throws java.io.IOException if an I/O error occurs
1402	>	*/
1403	>	private void readObject(java.io.ObjectInputStream s)
1404	>	throws java.io.IOException, ClassNotFoundException {
1405	>	/*
1406	>	* To improve performance in typical cases, we create nodes
1407	>	* while reading, then place in table once size is known.
1408	>	* However, we must also validate uniqueness and deal with
1409	>	* overpopulated bins while doing so, which requires
1410	>	* specialized versions of putVal mechanics.
1411	>	*/
1412	>	sizeCtl = -1; // force exclusion for table construction
1413	>	s.defaultReadObject();
1414	>	long size = 0L;
1415	>	Node<K,V> p = null;
1416	>	for (;;) {
1417	>	@SuppressWarnings("unchecked")
1418	>	K k = (K) s.readObject();
1419	>	@SuppressWarnings("unchecked")
1420	>	V v = (V) s.readObject();
1421	>	if (k != null && v != null) {
1422	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1423	>	++size;
1424	>	}
1425	>	else
1426	>	break;
1427	>	}
1428	>	if (size == 0L)
1429	>	sizeCtl = 0;
1430	>	else {
1431	>	int n;
1432	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1433	>	n = MAXIMUM_CAPACITY;
1434	>	else {
1435	>	int sz = (int)size;
1436	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1437	>	}
1438	>	@SuppressWarnings("unchecked")
1439	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1440	>	int mask = n - 1;
1441	>	long added = 0L;
1442	>	while (p != null) {
1443	>	boolean insertAtFront;
1444	>	Node<K,V> next = p.next, first;
1445	>	int h = p.hash, j = h & mask;
1446	>	if ((first = tabAt(tab, j)) == null)
1447	>	insertAtFront = true;
1448	>	else {
1449	>	K k = p.key;
1450	>	if (first.hash < 0) {
1451	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1452	>	if (t.putTreeVal(h, k, p.val) == null)
1453	>	++added;
1454	>	insertAtFront = false;
1455	>	}
1456	>	else {
1457	>	int binCount = 0;
1458	>	insertAtFront = true;
1459	>	Node<K,V> q; K qk;
1460	>	for (q = first; q != null; q = q.next) {
1461	>	if (q.hash == h &&
1462	>	((qk = q.key) == k ||
1463	>	(qk != null && k.equals(qk)))) {
1464	>	insertAtFront = false;
1465	>	break;
1466	>	}
1467	>	++binCount;
1468	>	}
1469	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1470	>	insertAtFront = false;
1471	>	++added;
1472	>	p.next = first;
1473	>	TreeNode<K,V> hd = null, tl = null;
1474	>	for (q = p; q != null; q = q.next) {
1475	>	TreeNode<K,V> t = new TreeNode<K,V>
1476	>	(q.hash, q.key, q.val, null, null);
1477	>	if ((t.prev = tl) == null)
1478	>	hd = t;
1479	>	else
1480	>	tl.next = t;
1481	>	tl = t;
1482	>	}
1483	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1484	>	}
1485	>	}
1486	>	}
1487	>	if (insertAtFront) {
1488	>	++added;
1489	>	p.next = first;
1490	>	setTabAt(tab, j, p);
1491		}
1492	+	p = next;
1493	+	}
1494	+	table = tab;
1495	+	sizeCtl = n - (n >>> 2);
1496	+	baseCount = added;
1497	+	}
1498	+	}
1499
1500	<	V v = e.value;
309	<	if (v == null || !oldValue.equals(v))
310	<	return false;
1500	>	// ConcurrentMap methods
1501
1502	<	e.value = newValue;
1503	<	count = c; // write-volatile
1504	<	return true;
1505	<
1506	<	} finally {
1507	<	unlock();
1502	>	/**
1503	>	* {@inheritDoc}
1504	>	*
1505	>	* @return the previous value associated with the specified key,
1506	>	*         or {@code null} if there was no mapping for the key
1507	>	* @throws NullPointerException if the specified key or value is null
1508	>	*/
1509	>	public V putIfAbsent(K key, V value) {
1510	>	return putVal(key, value, true);
1511	>	}
1512	>
1513	>	/**
1514	>	* {@inheritDoc}
1515	>	*
1516	>	* @throws NullPointerException if the specified key is null
1517	>	*/
1518	>	public boolean remove(Object key, Object value) {
1519	>	if (key == null)
1520	>	throw new NullPointerException();
1521	>	return value != null && replaceNode(key, null, value) != null;
1522	>	}
1523	>
1524	>	/**
1525	>	* {@inheritDoc}
1526	>	*
1527	>	* @throws NullPointerException if any of the arguments are null
1528	>	*/
1529	>	public boolean replace(K key, V oldValue, V newValue) {
1530	>	if (key == null || oldValue == null || newValue == null)
1531	>	throw new NullPointerException();
1532	>	return replaceNode(key, newValue, oldValue) != null;
1533	>	}
1534	>
1535	>	/**
1536	>	* {@inheritDoc}
1537	>	*
1538	>	* @return the previous value associated with the specified key,
1539	>	*         or {@code null} if there was no mapping for the key
1540	>	* @throws NullPointerException if the specified key or value is null
1541	>	*/
1542	>	public V replace(K key, V value) {
1543	>	if (key == null || value == null)
1544	>	throw new NullPointerException();
1545	>	return replaceNode(key, value, null);
1546	>	}
1547	>
1548	>	// Overrides of JDK8+ Map extension method defaults
1549	>
1550	>	/**
1551	>	* Returns the value to which the specified key is mapped, or the
1552	>	* given default value if this map contains no mapping for the
1553	>	* key.
1554	>	*
1555	>	* @param key the key whose associated value is to be returned
1556	>	* @param defaultValue the value to return if this map contains
1557	>	* no mapping for the given key
1558	>	* @return the mapping for the key, if present; else the default value
1559	>	* @throws NullPointerException if the specified key is null
1560	>	*/
1561	>	public V getOrDefault(Object key, V defaultValue) {
1562	>	V v;
1563	>	return (v = get(key)) == null ? defaultValue : v;
1564	>	}
1565	>
1566	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1567	>	if (action == null) throw new NullPointerException();
1568	>	Node<K,V>[] t;
1569	>	if ((t = table) != null) {
1570	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1571	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1572	>	action.accept(p.key, p.val);
1573		}
1574		}
1575	+	}
1576
1577	<	V replace(K key, int hash, V newValue) {
1578	<	lock();
1579	<	try {
1580	<	int c = count;
1581	<	HashEntry[] tab = table;
1582	<	int index = hash & (tab.length - 1);
1583	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1584	<	HashEntry<K,V> e = first;
1585	<	for (;;) {
1586	<	if (e == null)
1587	<	return null;
1588	<	if (e.hash == hash && key.equals(e.key))
1577	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1578	>	if (function == null) throw new NullPointerException();
1579	>	Node<K,V>[] t;
1580	>	if ((t = table) != null) {
1581	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1582	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1583	>	V oldValue = p.val;
1584	>	for (K key = p.key;;) {
1585	>	V newValue = function.apply(key, oldValue);
1586	>	if (newValue == null)
1587	>	throw new NullPointerException();
1588	>	if (replaceNode(key, newValue, oldValue) != null ||
1589	>	(oldValue = get(key)) == null)
1590		break;
334	–	e = e.next;
1591		}
1592	+	}
1593	+	}
1594	+	}
1595
1596	<	V v = e.value;
1597	<	e.value = newValue;
1598	<	count = c; // write-volatile
1599	<	return v;
1600	<
1601	<	} finally {
1602	<	unlock();
1596	>	/**
1597	>	* Helper method for EntrySet.removeIf
1598	>	*/
1599	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1600	>	if (function == null) throw new NullPointerException();
1601	>	Node<K,V>[] t;
1602	>	boolean removed = false;
1603	>	if ((t = table) != null) {
1604	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1605	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1606	>	K k = p.key;
1607	>	V v = p.val;
1608	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1609	>	if (function.test(e) && replaceNode(k, null, v) != null)
1610	>	removed = true;
1611		}
1612		}
1613	+	return removed;
1614	+	}
1615
1616	+	/**
1617	+	* Helper method for Values.removeIf
1618	+	*/
1619	+	boolean removeValueIf(Predicate<? super V> function) {
1620	+	if (function == null) throw new NullPointerException();
1621	+	Node<K,V>[] t;
1622	+	boolean removed = false;
1623	+	if ((t = table) != null) {
1624	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1625	+	for (Node<K,V> p; (p = it.advance()) != null; ) {
1626	+	K k = p.key;
1627	+	V v = p.val;
1628	+	if (function.test(v) && replaceNode(k, null, v) != null)
1629	+	removed = true;
1630	+	}
1631	+	}
1632	+	return removed;
1633	+	}
1634
1635	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
1636	<	lock();
1637	<	try {
1638	<	int c = count;
1639	<	HashEntry[] tab = table;
1640	<	int index = hash & (tab.length - 1);
1641	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1642	<
1643	<	for (HashEntry<K,V> e = first; e != null; e = (HashEntry<K,V>) e.next) {
1644	<	if (e.hash == hash && key.equals(e.key)) {
1645	<	V oldValue = e.value;
1646	<	if (!onlyIfAbsent)
1647	<	e.value = value;
1648	<	++modCount;
1649	<	count = c; // write-volatile
1650	<	return oldValue;
1635	>	/**
1636	>	* If the specified key is not already associated with a value,
1637	>	* attempts to compute its value using the given mapping function
1638	>	* and enters it into this map unless {@code null}.  The entire
1639	>	* method invocation is performed atomically, so the function is
1640	>	* applied at most once per key.  Some attempted update operations
1641	>	* on this map by other threads may be blocked while computation
1642	>	* is in progress, so the computation should be short and simple,
1643	>	* and must not attempt to update any other mappings of this map.
1644	>	*
1645	>	* @param key key with which the specified value is to be associated
1646	>	* @param mappingFunction the function to compute a value
1647	>	* @return the current (existing or computed) value associated with
1648	>	*         the specified key, or null if the computed value is null
1649	>	* @throws NullPointerException if the specified key or mappingFunction
1650	>	*         is null
1651	>	* @throws IllegalStateException if the computation detectably
1652	>	*         attempts a recursive update to this map that would
1653	>	*         otherwise never complete
1654	>	* @throws RuntimeException or Error if the mappingFunction does so,
1655	>	*         in which case the mapping is left unestablished
1656	>	*/
1657	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1658	>	if (key == null || mappingFunction == null)
1659	>	throw new NullPointerException();
1660	>	int h = spread(key.hashCode());
1661	>	V val = null;
1662	>	int binCount = 0;
1663	>	for (Node<K,V>[] tab = table;;) {
1664	>	Node<K,V> f; int n, i, fh;
1665	>	if (tab == null || (n = tab.length) == 0)
1666	>	tab = initTable();
1667	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1668	>	Node<K,V> r = new ReservationNode<K,V>();
1669	>	synchronized (r) {
1670	>	if (casTabAt(tab, i, null, r)) {
1671	>	binCount = 1;
1672	>	Node<K,V> node = null;
1673	>	try {
1674	>	if ((val = mappingFunction.apply(key)) != null)
1675	>	node = new Node<K,V>(h, key, val, null);
1676	>	} finally {
1677	>	setTabAt(tab, i, node);
1678	>	}
1679		}
1680		}
1681	<
1682	<	tab[index] = new HashEntry<K,V>(hash, key, value, first);
1683	<	++modCount;
1684	<	++c;
1685	<	count = c; // write-volatile
1686	<	if (c > threshold)
1687	<	setTable(rehash(tab));
1688	<	return null;
1689	<	} finally {
1690	<	unlock();
1681	>	if (binCount != 0)
1682	>	break;
1683	>	}
1684	>	else if ((fh = f.hash) == MOVED)
1685	>	tab = helpTransfer(tab, f);
1686	>	else {
1687	>	boolean added = false;
1688	>	synchronized (f) {
1689	>	if (tabAt(tab, i) == f) {
1690	>	if (fh >= 0) {
1691	>	binCount = 1;
1692	>	for (Node<K,V> e = f;; ++binCount) {
1693	>	K ek;
1694	>	if (e.hash == h &&
1695	>	((ek = e.key) == key ||
1696	>	(ek != null && key.equals(ek)))) {
1697	>	val = e.val;
1698	>	break;
1699	>	}
1700	>	Node<K,V> pred = e;
1701	>	if ((e = e.next) == null) {
1702	>	if ((val = mappingFunction.apply(key)) != null) {
1703	>	if (pred.next != null)
1704	>	throw new IllegalStateException("Recursive update");
1705	>	added = true;
1706	>	pred.next = new Node<K,V>(h, key, val, null);
1707	>	}
1708	>	break;
1709	>	}
1710	>	}
1711	>	}
1712	>	else if (f instanceof TreeBin) {
1713	>	binCount = 2;
1714	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1715	>	TreeNode<K,V> r, p;
1716	>	if ((r = t.root) != null &&
1717	>	(p = r.findTreeNode(h, key, null)) != null)
1718	>	val = p.val;
1719	>	else if ((val = mappingFunction.apply(key)) != null) {
1720	>	added = true;
1721	>	t.putTreeVal(h, key, val);
1722	>	}
1723	>	}
1724	>	else if (f instanceof ReservationNode)
1725	>	throw new IllegalStateException("Recursive update");
1726	>	}
1727	>	}
1728	>	if (binCount != 0) {
1729	>	if (binCount >= TREEIFY_THRESHOLD)
1730	>	treeifyBin(tab, i);
1731	>	if (!added)
1732	>	return val;
1733	>	break;
1734	>	}
1735		}
1736		}
1737	+	if (val != null)
1738	+	addCount(1L, binCount);
1739	+	return val;
1740	+	}
1741
1742	<	private HashEntry[] rehash(HashEntry[] oldTable) {
1743	<	int oldCapacity = oldTable.length;
1744	<	if (oldCapacity >= MAXIMUM_CAPACITY)
1745	<	return oldTable;
1746	<
1747	<	/*
1748	<	* Reclassify nodes in each list to new Map.  Because we are
1749	<	* using power-of-two expansion, the elements from each bin
1750	<	* must either stay at same index, or move with a power of two
1751	<	* offset. We eliminate unnecessary node creation by catching
1752	<	* cases where old nodes can be reused because their next
1753	<	* fields won't change. Statistically, at the default
1754	<	* threshold, only about one-sixth of them need cloning when
1755	<	* a table doubles. The nodes they replace will be garbage
1756	<	* collectable as soon as they are no longer referenced by any
1757	<	* reader thread that may be in the midst of traversing table
1758	<	* right now.
1759	<	*/
1760	<
1761	<	HashEntry[] newTable = new HashEntry[oldCapacity << 1];
1762	<	int sizeMask = newTable.length - 1;
1763	<	for (int i = 0; i < oldCapacity ; i++) {
1764	<	// We need to guarantee that any existing reads of old Map can
1765	<	//  proceed. So we cannot yet null out each bin.
1766	<	HashEntry<K,V> e = (HashEntry<K,V>)oldTable[i];
1767	<
1768	<	if (e != null) {
1769	<	HashEntry<K,V> next = e.next;
1770	<	int idx = e.hash & sizeMask;
1771	<
1772	<	//  Single node on list
1773	<	if (next == null)
1774	<	newTable[idx] = e;
1742	>	/**
1743	>	* If the value for the specified key is present, attempts to
1744	>	* compute a new mapping given the key and its current mapped
1745	>	* value.  The entire method invocation is performed atomically.
1746	>	* Some attempted update operations on this map by other threads
1747	>	* may be blocked while computation is in progress, so the
1748	>	* computation should be short and simple, and must not attempt to
1749	>	* update any other mappings of this map.
1750	>	*
1751	>	* @param key key with which a value may be associated
1752	>	* @param remappingFunction the function to compute a value
1753	>	* @return the new value associated with the specified key, or null if none
1754	>	* @throws NullPointerException if the specified key or remappingFunction
1755	>	*         is null
1756	>	* @throws IllegalStateException if the computation detectably
1757	>	*         attempts a recursive update to this map that would
1758	>	*         otherwise never complete
1759	>	* @throws RuntimeException or Error if the remappingFunction does so,
1760	>	*         in which case the mapping is unchanged
1761	>	*/
1762	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1763	>	if (key == null || remappingFunction == null)
1764	>	throw new NullPointerException();
1765	>	int h = spread(key.hashCode());
1766	>	V val = null;
1767	>	int delta = 0;
1768	>	int binCount = 0;
1769	>	for (Node<K,V>[] tab = table;;) {
1770	>	Node<K,V> f; int n, i, fh;
1771	>	if (tab == null || (n = tab.length) == 0)
1772	>	tab = initTable();
1773	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1774	>	break;
1775	>	else if ((fh = f.hash) == MOVED)
1776	>	tab = helpTransfer(tab, f);
1777	>	else {
1778	>	synchronized (f) {
1779	>	if (tabAt(tab, i) == f) {
1780	>	if (fh >= 0) {
1781	>	binCount = 1;
1782	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1783	>	K ek;
1784	>	if (e.hash == h &&
1785	>	((ek = e.key) == key ||
1786	>	(ek != null && key.equals(ek)))) {
1787	>	val = remappingFunction.apply(key, e.val);
1788	>	if (val != null)
1789	>	e.val = val;
1790	>	else {
1791	>	delta = -1;
1792	>	Node<K,V> en = e.next;
1793	>	if (pred != null)
1794	>	pred.next = en;
1795	>	else
1796	>	setTabAt(tab, i, en);
1797	>	}
1798	>	break;
1799	>	}
1800	>	pred = e;
1801	>	if ((e = e.next) == null)
1802	>	break;
1803	>	}
1804	>	}
1805	>	else if (f instanceof TreeBin) {
1806	>	binCount = 2;
1807	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1808	>	TreeNode<K,V> r, p;
1809	>	if ((r = t.root) != null &&
1810	>	(p = r.findTreeNode(h, key, null)) != null) {
1811	>	val = remappingFunction.apply(key, p.val);
1812	>	if (val != null)
1813	>	p.val = val;
1814	>	else {
1815	>	delta = -1;
1816	>	if (t.removeTreeNode(p))
1817	>	setTabAt(tab, i, untreeify(t.first));
1818	>	}
1819	>	}
1820	>	}
1821	>	else if (f instanceof ReservationNode)
1822	>	throw new IllegalStateException("Recursive update");
1823	>	}
1824	>	}
1825	>	if (binCount != 0)
1826	>	break;
1827	>	}
1828	>	}
1829	>	if (delta != 0)
1830	>	addCount((long)delta, binCount);
1831	>	return val;
1832	>	}
1833
1834	<	else {
1835	<	// Reuse trailing consecutive sequence at same slot
1836	<	HashEntry<K,V> lastRun = e;
1837	<	int lastIdx = idx;
1838	<	for (HashEntry<K,V> last = next;
1839	<	last != null;
1840	<	last = last.next) {
1841	<	int k = last.hash & sizeMask;
1842	<	if (k != lastIdx) {
1843	<	lastIdx = k;
1844	<	lastRun = last;
1834	>	/**
1835	>	* Attempts to compute a mapping for the specified key and its
1836	>	* current mapped value (or {@code null} if there is no current
1837	>	* mapping). The entire method invocation is performed atomically.
1838	>	* Some attempted update operations on this map by other threads
1839	>	* may be blocked while computation is in progress, so the
1840	>	* computation should be short and simple, and must not attempt to
1841	>	* update any other mappings of this Map.
1842	>	*
1843	>	* @param key key with which the specified value is to be associated
1844	>	* @param remappingFunction the function to compute a value
1845	>	* @return the new value associated with the specified key, or null if none
1846	>	* @throws NullPointerException if the specified key or remappingFunction
1847	>	*         is null
1848	>	* @throws IllegalStateException if the computation detectably
1849	>	*         attempts a recursive update to this map that would
1850	>	*         otherwise never complete
1851	>	* @throws RuntimeException or Error if the remappingFunction does so,
1852	>	*         in which case the mapping is unchanged
1853	>	*/
1854	>	public V compute(K key,
1855	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1856	>	if (key == null || remappingFunction == null)
1857	>	throw new NullPointerException();
1858	>	int h = spread(key.hashCode());
1859	>	V val = null;
1860	>	int delta = 0;
1861	>	int binCount = 0;
1862	>	for (Node<K,V>[] tab = table;;) {
1863	>	Node<K,V> f; int n, i, fh;
1864	>	if (tab == null || (n = tab.length) == 0)
1865	>	tab = initTable();
1866	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1867	>	Node<K,V> r = new ReservationNode<K,V>();
1868	>	synchronized (r) {
1869	>	if (casTabAt(tab, i, null, r)) {
1870	>	binCount = 1;
1871	>	Node<K,V> node = null;
1872	>	try {
1873	>	if ((val = remappingFunction.apply(key, null)) != null) {
1874	>	delta = 1;
1875	>	node = new Node<K,V>(h, key, val, null);
1876		}
1877	+	} finally {
1878	+	setTabAt(tab, i, node);
1879		}
1880	<	newTable[lastIdx] = lastRun;
1880	>	}
1881	>	}
1882	>	if (binCount != 0)
1883	>	break;
1884	>	}
1885	>	else if ((fh = f.hash) == MOVED)
1886	>	tab = helpTransfer(tab, f);
1887	>	else {
1888	>	synchronized (f) {
1889	>	if (tabAt(tab, i) == f) {
1890	>	if (fh >= 0) {
1891	>	binCount = 1;
1892	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1893	>	K ek;
1894	>	if (e.hash == h &&
1895	>	((ek = e.key) == key ||
1896	>	(ek != null && key.equals(ek)))) {
1897	>	val = remappingFunction.apply(key, e.val);
1898	>	if (val != null)
1899	>	e.val = val;
1900	>	else {
1901	>	delta = -1;
1902	>	Node<K,V> en = e.next;
1903	>	if (pred != null)
1904	>	pred.next = en;
1905	>	else
1906	>	setTabAt(tab, i, en);
1907	>	}
1908	>	break;
1909	>	}
1910	>	pred = e;
1911	>	if ((e = e.next) == null) {
1912	>	val = remappingFunction.apply(key, null);
1913	>	if (val != null) {
1914	>	if (pred.next != null)
1915	>	throw new IllegalStateException("Recursive update");
1916	>	delta = 1;
1917	>	pred.next =
1918	>	new Node<K,V>(h, key, val, null);
1919	>	}
1920	>	break;
1921	>	}
1922	>	}
1923	>	}
1924	>	else if (f instanceof TreeBin) {
1925	>	binCount = 1;
1926	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1927	>	TreeNode<K,V> r, p;
1928	>	if ((r = t.root) != null)
1929	>	p = r.findTreeNode(h, key, null);
1930	>	else
1931	>	p = null;
1932	>	V pv = (p == null) ? null : p.val;
1933	>	val = remappingFunction.apply(key, pv);
1934	>	if (val != null) {
1935	>	if (p != null)
1936	>	p.val = val;
1937	>	else {
1938	>	delta = 1;
1939	>	t.putTreeVal(h, key, val);
1940	>	}
1941	>	}
1942	>	else if (p != null) {
1943	>	delta = -1;
1944	>	if (t.removeTreeNode(p))
1945	>	setTabAt(tab, i, untreeify(t.first));
1946	>	}
1947	>	}
1948	>	else if (f instanceof ReservationNode)
1949	>	throw new IllegalStateException("Recursive update");
1950	>	}
1951	>	}
1952	>	if (binCount != 0) {
1953	>	if (binCount >= TREEIFY_THRESHOLD)
1954	>	treeifyBin(tab, i);
1955	>	break;
1956	>	}
1957	>	}
1958	>	}
1959	>	if (delta != 0)
1960	>	addCount((long)delta, binCount);
1961	>	return val;
1962	>	}
1963
1964	<	// Clone all remaining nodes
1965	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1966	<	int k = p.hash & sizeMask;
1967	<	newTable[k] = new HashEntry<K,V>(p.hash,
1968	<	p.key,
1969	<	p.value,
1970	<	(HashEntry<K,V>) newTable[k]);
1964	>	/**
1965	>	* If the specified key is not already associated with a
1966	>	* (non-null) value, associates it with the given value.
1967	>	* Otherwise, replaces the value with the results of the given
1968	>	* remapping function, or removes if {@code null}. The entire
1969	>	* method invocation is performed atomically.  Some attempted
1970	>	* update operations on this map by other threads may be blocked
1971	>	* while computation is in progress, so the computation should be
1972	>	* short and simple, and must not attempt to update any other
1973	>	* mappings of this Map.
1974	>	*
1975	>	* @param key key with which the specified value is to be associated
1976	>	* @param value the value to use if absent
1977	>	* @param remappingFunction the function to recompute a value if present
1978	>	* @return the new value associated with the specified key, or null if none
1979	>	* @throws NullPointerException if the specified key or the
1980	>	*         remappingFunction is null
1981	>	* @throws RuntimeException or Error if the remappingFunction does so,
1982	>	*         in which case the mapping is unchanged
1983	>	*/
1984	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1985	>	if (key == null || value == null || remappingFunction == null)
1986	>	throw new NullPointerException();
1987	>	int h = spread(key.hashCode());
1988	>	V val = null;
1989	>	int delta = 0;
1990	>	int binCount = 0;
1991	>	for (Node<K,V>[] tab = table;;) {
1992	>	Node<K,V> f; int n, i, fh;
1993	>	if (tab == null || (n = tab.length) == 0)
1994	>	tab = initTable();
1995	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1996	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1997	>	delta = 1;
1998	>	val = value;
1999	>	break;
2000	>	}
2001	>	}
2002	>	else if ((fh = f.hash) == MOVED)
2003	>	tab = helpTransfer(tab, f);
2004	>	else {
2005	>	synchronized (f) {
2006	>	if (tabAt(tab, i) == f) {
2007	>	if (fh >= 0) {
2008	>	binCount = 1;
2009	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2010	>	K ek;
2011	>	if (e.hash == h &&
2012	>	((ek = e.key) == key ||
2013	>	(ek != null && key.equals(ek)))) {
2014	>	val = remappingFunction.apply(e.val, value);
2015	>	if (val != null)
2016	>	e.val = val;
2017	>	else {
2018	>	delta = -1;
2019	>	Node<K,V> en = e.next;
2020	>	if (pred != null)
2021	>	pred.next = en;
2022	>	else
2023	>	setTabAt(tab, i, en);
2024	>	}
2025	>	break;
2026	>	}
2027	>	pred = e;
2028	>	if ((e = e.next) == null) {
2029	>	delta = 1;
2030	>	val = value;
2031	>	pred.next =
2032	>	new Node<K,V>(h, key, val, null);
2033	>	break;
2034	>	}
2035	>	}
2036		}
2037	+	else if (f instanceof TreeBin) {
2038	+	binCount = 2;
2039	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
2040	+	TreeNode<K,V> r = t.root;
2041	+	TreeNode<K,V> p = (r == null) ? null :
2042	+	r.findTreeNode(h, key, null);
2043	+	val = (p == null) ? value :
2044	+	remappingFunction.apply(p.val, value);
2045	+	if (val != null) {
2046	+	if (p != null)
2047	+	p.val = val;
2048	+	else {
2049	+	delta = 1;
2050	+	t.putTreeVal(h, key, val);
2051	+	}
2052	+	}
2053	+	else if (p != null) {
2054	+	delta = -1;
2055	+	if (t.removeTreeNode(p))
2056	+	setTabAt(tab, i, untreeify(t.first));
2057	+	}
2058	+	}
2059	+	else if (f instanceof ReservationNode)
2060	+	throw new IllegalStateException("Recursive update");
2061		}
2062		}
2063	+	if (binCount != 0) {
2064	+	if (binCount >= TREEIFY_THRESHOLD)
2065	+	treeifyBin(tab, i);
2066	+	break;
2067	+	}
2068		}
439	–	return newTable;
2069		}
2070	+	if (delta != 0)
2071	+	addCount((long)delta, binCount);
2072	+	return val;
2073	+	}
2074
2075	<	/**
2076	<	* Remove; match on key only if value null, else match both.
2077	<	*/
2078	<	V remove(Object key, int hash, Object value) {
2079	<	lock();
2080	<	try {
2081	<	int c = count;
2082	<	HashEntry[] tab = table;
2083	<	int index = hash & (tab.length - 1);
2084	<	HashEntry<K,V> first = (HashEntry<K,V>)tab[index];
2075	>	// Hashtable legacy methods
2076	>
2077	>	/**
2078	>	* Tests if some key maps into the specified value in this table.
2079	>	*
2080	>	* <p>Note that this method is identical in functionality to
2081	>	* {@link #containsValue(Object)}, and exists solely to ensure
2082	>	* full compatibility with class {@link java.util.Hashtable},
2083	>	* which supported this method prior to introduction of the Java
2084	>	* Collections Framework.
2085	>	*
2086	>	* @param  value a value to search for
2087	>	* @return {@code true} if and only if some key maps to the
2088	>	*         {@code value} argument in this table as
2089	>	*         determined by the {@code equals} method;
2090	>	*         {@code false} otherwise
2091	>	* @throws NullPointerException if the specified value is null
2092	>	*/
2093	>	public boolean contains(Object value) {
2094	>	return containsValue(value);
2095	>	}
2096
2097	<	HashEntry<K,V> e = first;
2097	>	/**
2098	>	* Returns an enumeration of the keys in this table.
2099	>	*
2100	>	* @return an enumeration of the keys in this table
2101	>	* @see #keySet()
2102	>	*/
2103	>	public Enumeration<K> keys() {
2104	>	Node<K,V>[] t;
2105	>	int f = (t = table) == null ? 0 : t.length;
2106	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2107	>	}
2108	>
2109	>	/**
2110	>	* Returns an enumeration of the values in this table.
2111	>	*
2112	>	* @return an enumeration of the values in this table
2113	>	* @see #values()
2114	>	*/
2115	>	public Enumeration<V> elements() {
2116	>	Node<K,V>[] t;
2117	>	int f = (t = table) == null ? 0 : t.length;
2118	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2119	>	}
2120	>
2121	>	// ConcurrentHashMap-only methods
2122	>
2123	>	/**
2124	>	* Returns the number of mappings. This method should be used
2125	>	* instead of {@link #size} because a ConcurrentHashMap may
2126	>	* contain more mappings than can be represented as an int. The
2127	>	* value returned is an estimate; the actual count may differ if
2128	>	* there are concurrent insertions or removals.
2129	>	*
2130	>	* @return the number of mappings
2131	>	* @since 1.8
2132	>	*/
2133	>	public long mappingCount() {
2134	>	long n = sumCount();
2135	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2136	>	}
2137	>
2138	>	/**
2139	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2140	>	* from the given type to {@code Boolean.TRUE}.
2141	>	*
2142	>	* @param <K> the element type of the returned set
2143	>	* @return the new set
2144	>	* @since 1.8
2145	>	*/
2146	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2147	>	return new KeySetView<K,Boolean>
2148	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2149	>	}
2150	>
2151	>	/**
2152	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2153	>	* from the given type to {@code Boolean.TRUE}.
2154	>	*
2155	>	* @param initialCapacity The implementation performs internal
2156	>	* sizing to accommodate this many elements.
2157	>	* @param <K> the element type of the returned set
2158	>	* @return the new set
2159	>	* @throws IllegalArgumentException if the initial capacity of
2160	>	* elements is negative
2161	>	* @since 1.8
2162	>	*/
2163	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2164	>	return new KeySetView<K,Boolean>
2165	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2166	>	}
2167	>
2168	>	/**
2169	>	* Returns a {@link Set} view of the keys in this map, using the
2170	>	* given common mapped value for any additions (i.e., {@link
2171	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2172	>	* This is of course only appropriate if it is acceptable to use
2173	>	* the same value for all additions from this view.
2174	>	*
2175	>	* @param mappedValue the mapped value to use for any additions
2176	>	* @return the set view
2177	>	* @throws NullPointerException if the mappedValue is null
2178	>	*/
2179	>	public KeySetView<K,V> keySet(V mappedValue) {
2180	>	if (mappedValue == null)
2181	>	throw new NullPointerException();
2182	>	return new KeySetView<K,V>(this, mappedValue);
2183	>	}
2184	>
2185	>	/* ---------------- Special Nodes -------------- */
2186	>
2187	>	/**
2188	>	* A node inserted at head of bins during transfer operations.
2189	>	*/
2190	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2191	>	final Node<K,V>[] nextTable;
2192	>	ForwardingNode(Node<K,V>[] tab) {
2193	>	super(MOVED, null, null, null);
2194	>	this.nextTable = tab;
2195	>	}
2196	>
2197	>	Node<K,V> find(int h, Object k) {
2198	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2199	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2200	>	Node<K,V> e; int n;
2201	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2202	>	(e = tabAt(tab, (n - 1) & h)) == null)
2203	>	return null;
2204		for (;;) {
2205	<	if (e == null)
2205	>	int eh; K ek;
2206	>	if ((eh = e.hash) == h &&
2207	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2208	>	return e;
2209	>	if (eh < 0) {
2210	>	if (e instanceof ForwardingNode) {
2211	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2212	>	continue outer;
2213	>	}
2214	>	else
2215	>	return e.find(h, k);
2216	>	}
2217	>	if ((e = e.next) == null)
2218		return null;
457	–	if (e.hash == hash && key.equals(e.key))
458	–	break;
459	–	e = e.next;
2219		}
2220	+	}
2221	+	}
2222	+	}
2223
2224	<	V oldValue = e.value;
2225	<	if (value != null && !value.equals(oldValue))
2226	<	return null;
2224	>	/**
2225	>	* A place-holder node used in computeIfAbsent and compute
2226	>	*/
2227	>	static final class ReservationNode<K,V> extends Node<K,V> {
2228	>	ReservationNode() {
2229	>	super(RESERVED, null, null, null);
2230	>	}
2231
2232	<	// All entries following removed node can stay in list, but
2233	<	// all preceding ones need to be cloned.
2234	<	HashEntry<K,V> newFirst = e.next;
2235	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
2236	<	newFirst = new HashEntry<K,V>(p.hash, p.key,
2237	<	p.value, newFirst);
2238	<	tab[index] = newFirst;
2239	<	++modCount;
2240	<	count = c-1; // write-volatile
2241	<	return oldValue;
2242	<	} finally {
2243	<	unlock();
2232	>	Node<K,V> find(int h, Object k) {
2233	>	return null;
2234	>	}
2235	>	}
2236	>
2237	>	/* ---------------- Table Initialization and Resizing -------------- */
2238	>
2239	>	/**
2240	>	* Returns the stamp bits for resizing a table of size n.
2241	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2242	>	*/
2243	>	static final int resizeStamp(int n) {
2244	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2245	>	}
2246	>
2247	>	/**
2248	>	* Initializes table, using the size recorded in sizeCtl.
2249	>	*/
2250	>	private final Node<K,V>[] initTable() {
2251	>	Node<K,V>[] tab; int sc;
2252	>	while ((tab = table) == null || tab.length == 0) {
2253	>	if ((sc = sizeCtl) < 0)
2254	>	Thread.yield(); // lost initialization race; just spin
2255	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2256	>	try {
2257	>	if ((tab = table) == null || tab.length == 0) {
2258	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2259	>	@SuppressWarnings("unchecked")
2260	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2261	>	table = tab = nt;
2262	>	sc = n - (n >>> 2);
2263	>	}
2264	>	} finally {
2265	>	sizeCtl = sc;
2266	>	}
2267	>	break;
2268		}
2269		}
2270	+	return tab;
2271	+	}
2272
2273	<	void clear() {
2274	<	lock();
2275	<	try {
2276	<	HashEntry[] tab = table;
2277	<	for (int i = 0; i < tab.length ; i++)
2278	<	tab[i] = null;
2279	<	++modCount;
2280	<	count = 0; // write-volatile
2281	<	} finally {
2282	<	unlock();
2273	>	/**
2274	>	* Adds to count, and if table is too small and not already
2275	>	* resizing, initiates transfer. If already resizing, helps
2276	>	* perform transfer if work is available.  Rechecks occupancy
2277	>	* after a transfer to see if another resize is already needed
2278	>	* because resizings are lagging additions.
2279	>	*
2280	>	* @param x the count to add
2281	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2282	>	*/
2283	>	private final void addCount(long x, int check) {
2284	>	CounterCell[] as; long b, s;
2285	>	if ((as = counterCells) != null ||
2286	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2287	>	CounterCell a; long v; int m;
2288	>	boolean uncontended = true;
2289	>	if (as == null || (m = as.length - 1) < 0 ||
2290	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2291	>	!(uncontended =
2292	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2293	>	fullAddCount(x, uncontended);
2294	>	return;
2295	>	}
2296	>	if (check <= 1)
2297	>	return;
2298	>	s = sumCount();
2299	>	}
2300	>	if (check >= 0) {
2301	>	Node<K,V>[] tab, nt; int n, sc;
2302	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2303	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2304	>	int rs = resizeStamp(n);
2305	>	if (sc < 0) {
2306	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2307	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2308	>	transferIndex <= 0)
2309	>	break;
2310	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2311	>	transfer(tab, nt);
2312	>	}
2313	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2314	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2315	>	transfer(tab, null);
2316	>	s = sumCount();
2317		}
2318		}
2319		}
2320
2321		/**
2322	<	* ConcurrentHashMap list entry. Note that this is never exported
497	<	* out as a user-visible Map.Entry
2322	>	* Helps transfer if a resize is in progress.
2323		*/
2324	<	private static class HashEntry<K,V> {
2325	<	private final K key;
2326	<	private V value;
2327	<	private final int hash;
2328	<	private final HashEntry<K,V> next;
2324	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2325	>	Node<K,V>[] nextTab; int sc;
2326	>	if (tab != null && (f instanceof ForwardingNode) &&
2327	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2328	>	int rs = resizeStamp(tab.length);
2329	>	while (nextTab == nextTable && table == tab &&
2330	>	(sc = sizeCtl) < 0) {
2331	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2332	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2333	>	break;
2334	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2335	>	transfer(tab, nextTab);
2336	>	break;
2337	>	}
2338	>	}
2339	>	return nextTab;
2340	>	}
2341	>	return table;
2342	>	}
2343
2344	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
2345	<	this.value = value;
2346	<	this.hash = hash;
2347	<	this.key = key;
2348	<	this.next = next;
2344	>	/**
2345	>	* Tries to presize table to accommodate the given number of elements.
2346	>	*
2347	>	* @param size number of elements (doesn't need to be perfectly accurate)
2348	>	*/
2349	>	private final void tryPresize(int size) {
2350	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2351	>	tableSizeFor(size + (size >>> 1) + 1);
2352	>	int sc;
2353	>	while ((sc = sizeCtl) >= 0) {
2354	>	Node<K,V>[] tab = table; int n;
2355	>	if (tab == null || (n = tab.length) == 0) {
2356	>	n = (sc > c) ? sc : c;
2357	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2358	>	try {
2359	>	if (table == tab) {
2360	>	@SuppressWarnings("unchecked")
2361	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2362	>	table = nt;
2363	>	sc = n - (n >>> 2);
2364	>	}
2365	>	} finally {
2366	>	sizeCtl = sc;
2367	>	}
2368	>	}
2369	>	}
2370	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2371	>	break;
2372	>	else if (tab == table) {
2373	>	int rs = resizeStamp(n);
2374	>	if (U.compareAndSwapInt(this, SIZECTL, sc,
2375	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2376	>	transfer(tab, null);
2377	>	}
2378		}
2379		}
2380
2381	+	/**
2382	+	* Moves and/or copies the nodes in each bin to new table. See
2383	+	* above for explanation.
2384	+	*/
2385	+	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2386	+	int n = tab.length, stride;
2387	+	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2388	+	stride = MIN_TRANSFER_STRIDE; // subdivide range
2389	+	if (nextTab == null) {            // initiating
2390	+	try {
2391	+	@SuppressWarnings("unchecked")
2392	+	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2393	+	nextTab = nt;
2394	+	} catch (Throwable ex) {      // try to cope with OOME
2395	+	sizeCtl = Integer.MAX_VALUE;
2396	+	return;
2397	+	}
2398	+	nextTable = nextTab;
2399	+	transferIndex = n;
2400	+	}
2401	+	int nextn = nextTab.length;
2402	+	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2403	+	boolean advance = true;
2404	+	boolean finishing = false; // to ensure sweep before committing nextTab
2405	+	for (int i = 0, bound = 0;;) {
2406	+	Node<K,V> f; int fh;
2407	+	while (advance) {
2408	+	int nextIndex, nextBound;
2409	+	if (--i >= bound || finishing)
2410	+	advance = false;
2411	+	else if ((nextIndex = transferIndex) <= 0) {
2412	+	i = -1;
2413	+	advance = false;
2414	+	}
2415	+	else if (U.compareAndSwapInt
2416	+	(this, TRANSFERINDEX, nextIndex,
2417	+	nextBound = (nextIndex > stride ?
2418	+	nextIndex - stride : 0))) {
2419	+	bound = nextBound;
2420	+	i = nextIndex - 1;
2421	+	advance = false;
2422	+	}
2423	+	}
2424	+	if (i < 0 || i >= n || i + n >= nextn) {
2425	+	int sc;
2426	+	if (finishing) {
2427	+	nextTable = null;
2428	+	table = nextTab;
2429	+	sizeCtl = (n << 1) - (n >>> 1);
2430	+	return;
2431	+	}
2432	+	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2433	+	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2434	+	return;
2435	+	finishing = advance = true;
2436	+	i = n; // recheck before commit
2437	+	}
2438	+	}
2439	+	else if ((f = tabAt(tab, i)) == null)
2440	+	advance = casTabAt(tab, i, null, fwd);
2441	+	else if ((fh = f.hash) == MOVED)
2442	+	advance = true; // already processed
2443	+	else {
2444	+	synchronized (f) {
2445	+	if (tabAt(tab, i) == f) {
2446	+	Node<K,V> ln, hn;
2447	+	if (fh >= 0) {
2448	+	int runBit = fh & n;
2449	+	Node<K,V> lastRun = f;
2450	+	for (Node<K,V> p = f.next; p != null; p = p.next) {
2451	+	int b = p.hash & n;
2452	+	if (b != runBit) {
2453	+	runBit = b;
2454	+	lastRun = p;
2455	+	}
2456	+	}
2457	+	if (runBit == 0) {
2458	+	ln = lastRun;
2459	+	hn = null;
2460	+	}
2461	+	else {
2462	+	hn = lastRun;
2463	+	ln = null;
2464	+	}
2465	+	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2466	+	int ph = p.hash; K pk = p.key; V pv = p.val;
2467	+	if ((ph & n) == 0)
2468	+	ln = new Node<K,V>(ph, pk, pv, ln);
2469	+	else
2470	+	hn = new Node<K,V>(ph, pk, pv, hn);
2471	+	}
2472	+	setTabAt(nextTab, i, ln);
2473	+	setTabAt(nextTab, i + n, hn);
2474	+	setTabAt(tab, i, fwd);
2475	+	advance = true;
2476	+	}
2477	+	else if (f instanceof TreeBin) {
2478	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
2479	+	TreeNode<K,V> lo = null, loTail = null;
2480	+	TreeNode<K,V> hi = null, hiTail = null;
2481	+	int lc = 0, hc = 0;
2482	+	for (Node<K,V> e = t.first; e != null; e = e.next) {
2483	+	int h = e.hash;
2484	+	TreeNode<K,V> p = new TreeNode<K,V>
2485	+	(h, e.key, e.val, null, null);
2486	+	if ((h & n) == 0) {
2487	+	if ((p.prev = loTail) == null)
2488	+	lo = p;
2489	+	else
2490	+	loTail.next = p;
2491	+	loTail = p;
2492	+	++lc;
2493	+	}
2494	+	else {
2495	+	if ((p.prev = hiTail) == null)
2496	+	hi = p;
2497	+	else
2498	+	hiTail.next = p;
2499	+	hiTail = p;
2500	+	++hc;
2501	+	}
2502	+	}
2503	+	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2504	+	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2505	+	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2506	+	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2507	+	setTabAt(nextTab, i, ln);
2508	+	setTabAt(nextTab, i + n, hn);
2509	+	setTabAt(tab, i, fwd);
2510	+	advance = true;
2511	+	}
2512	+	}
2513	+	}
2514	+	}
2515	+	}
2516	+	}
2517
2518	<	/* ---------------- Public operations -------------- */
2518	>	/* ---------------- Counter support -------------- */
2519
2520		/**
2521	<	* Constructs a new, empty map with the specified initial
2522	<	* capacity and the specified load factor.
519	<	*
520	<	* @param initialCapacity the initial capacity. The implementation
521	<	* performs internal sizing to accommodate this many elements.
522	<	* @param loadFactor  the load factor threshold, used to control resizing.
523	<	* @param concurrencyLevel the estimated number of concurrently
524	<	* updating threads. The implementation performs internal sizing
525	<	* to try to accommodate this many threads.
526	<	* @throws IllegalArgumentException if the initial capacity is
527	<	* negative or the load factor or concurrencyLevel are
528	<	* nonpositive.
2521	>	* A padded cell for distributing counts.  Adapted from LongAdder
2522	>	* and Striped64.  See their internal docs for explanation.
2523		*/
2524	<	public ConcurrentHashMap(int initialCapacity,
2525	<	float loadFactor, int concurrencyLevel) {
2526	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
2527	<	throw new IllegalArgumentException();
534	<
535	<	if (concurrencyLevel > MAX_SEGMENTS)
536	<	concurrencyLevel = MAX_SEGMENTS;
2524	>	@sun.misc.Contended static final class CounterCell {
2525	>	volatile long value;
2526	>	CounterCell(long x) { value = x; }
2527	>	}
2528
2529	<	// Find power-of-two sizes best matching arguments
2530	<	int sshift = 0;
2531	<	int ssize = 1;
2532	<	while (ssize < concurrencyLevel) {
2533	<	++sshift;
2534	<	ssize <<= 1;
2529	>	final long sumCount() {
2530	>	CounterCell[] as = counterCells; CounterCell a;
2531	>	long sum = baseCount;
2532	>	if (as != null) {
2533	>	for (int i = 0; i < as.length; ++i) {
2534	>	if ((a = as[i]) != null)
2535	>	sum += a.value;
2536	>	}
2537		}
2538	<	segmentShift = 32 - sshift;
2539	<	segmentMask = ssize - 1;
547	<	this.segments = new Segment[ssize];
548	<
549	<	if (initialCapacity > MAXIMUM_CAPACITY)
550	<	initialCapacity = MAXIMUM_CAPACITY;
551	<	int c = initialCapacity / ssize;
552	<	if (c * ssize < initialCapacity)
553	<	++c;
554	<	int cap = 1;
555	<	while (cap < c)
556	<	cap <<= 1;
2538	>	return sum;
2539	>	}
2540
2541	<	for (int i = 0; i < this.segments.length; ++i)
2542	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
2541	>	// See LongAdder version for explanation
2542	>	private final void fullAddCount(long x, boolean wasUncontended) {
2543	>	int h;
2544	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2545	>	ThreadLocalRandom.localInit();      // force initialization
2546	>	h = ThreadLocalRandom.getProbe();
2547	>	wasUncontended = true;
2548	>	}
2549	>	boolean collide = false;                // True if last slot nonempty
2550	>	for (;;) {
2551	>	CounterCell[] as; CounterCell a; int n; long v;
2552	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2553	>	if ((a = as[(n - 1) & h]) == null) {
2554	>	if (cellsBusy == 0) {            // Try to attach new Cell
2555	>	CounterCell r = new CounterCell(x); // Optimistic create
2556	>	if (cellsBusy == 0 &&
2557	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2558	>	boolean created = false;
2559	>	try {               // Recheck under lock
2560	>	CounterCell[] rs; int m, j;
2561	>	if ((rs = counterCells) != null &&
2562	>	(m = rs.length) > 0 &&
2563	>	rs[j = (m - 1) & h] == null) {
2564	>	rs[j] = r;
2565	>	created = true;
2566	>	}
2567	>	} finally {
2568	>	cellsBusy = 0;
2569	>	}
2570	>	if (created)
2571	>	break;
2572	>	continue;           // Slot is now non-empty
2573	>	}
2574	>	}
2575	>	collide = false;
2576	>	}
2577	>	else if (!wasUncontended)       // CAS already known to fail
2578	>	wasUncontended = true;      // Continue after rehash
2579	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2580	>	break;
2581	>	else if (counterCells != as || n >= NCPU)
2582	>	collide = false;            // At max size or stale
2583	>	else if (!collide)
2584	>	collide = true;
2585	>	else if (cellsBusy == 0 &&
2586	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2587	>	try {
2588	>	if (counterCells == as) {// Expand table unless stale
2589	>	CounterCell[] rs = new CounterCell[n << 1];
2590	>	for (int i = 0; i < n; ++i)
2591	>	rs[i] = as[i];
2592	>	counterCells = rs;
2593	>	}
2594	>	} finally {
2595	>	cellsBusy = 0;
2596	>	}
2597	>	collide = false;
2598	>	continue;                   // Retry with expanded table
2599	>	}
2600	>	h = ThreadLocalRandom.advanceProbe(h);
2601	>	}
2602	>	else if (cellsBusy == 0 && counterCells == as &&
2603	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2604	>	boolean init = false;
2605	>	try {                           // Initialize table
2606	>	if (counterCells == as) {
2607	>	CounterCell[] rs = new CounterCell[2];
2608	>	rs[h & 1] = new CounterCell(x);
2609	>	counterCells = rs;
2610	>	init = true;
2611	>	}
2612	>	} finally {
2613	>	cellsBusy = 0;
2614	>	}
2615	>	if (init)
2616	>	break;
2617	>	}
2618	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2619	>	break;                          // Fall back on using base
2620	>	}
2621		}
2622
2623	+	/* ---------------- Conversion from/to TreeBins -------------- */
2624	+
2625		/**
2626	<	* Constructs a new, empty map with the specified initial
2627	<	* capacity,  and with default load factor and concurrencyLevel.
565	<	*
566	<	* @param initialCapacity The implementation performs internal
567	<	* sizing to accommodate this many elements.
568	<	* @throws IllegalArgumentException if the initial capacity of
569	<	* elements is negative.
2626	>	* Replaces all linked nodes in bin at given index unless table is
2627	>	* too small, in which case resizes instead.
2628		*/
2629	<	public ConcurrentHashMap(int initialCapacity) {
2630	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2629	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2630	>	Node<K,V> b; int n;
2631	>	if (tab != null) {
2632	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2633	>	tryPresize(n << 1);
2634	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2635	>	synchronized (b) {
2636	>	if (tabAt(tab, index) == b) {
2637	>	TreeNode<K,V> hd = null, tl = null;
2638	>	for (Node<K,V> e = b; e != null; e = e.next) {
2639	>	TreeNode<K,V> p =
2640	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2641	>	null, null);
2642	>	if ((p.prev = tl) == null)
2643	>	hd = p;
2644	>	else
2645	>	tl.next = p;
2646	>	tl = p;
2647	>	}
2648	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2649	>	}
2650	>	}
2651	>	}
2652	>	}
2653		}
2654
2655		/**
2656	<	* Constructs a new, empty map with a default initial capacity,
577	<	* load factor, and concurrencyLevel.
2656	>	* Returns a list on non-TreeNodes replacing those in given list.
2657		*/
2658	<	public ConcurrentHashMap() {
2659	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2658	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2659	>	Node<K,V> hd = null, tl = null;
2660	>	for (Node<K,V> q = b; q != null; q = q.next) {
2661	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2662	>	if (tl == null)
2663	>	hd = p;
2664	>	else
2665	>	tl.next = p;
2666	>	tl = p;
2667	>	}
2668	>	return hd;
2669		}
2670
2671	+	/* ---------------- TreeNodes -------------- */
2672	+
2673		/**
2674	<	* Constructs a new map with the same mappings as the given map.  The
585	<	* map is created with a capacity of twice the number of mappings in
586	<	* the given map or 11 (whichever is greater), and a default load factor.
2674	>	* Nodes for use in TreeBins
2675		*/
2676	<	public <A extends K, B extends V> ConcurrentHashMap(Map<A,B> t) {
2677	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
2678	<	11),
2679	<	DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2680	<	putAll(t);
2681	<	}
2676	>	static final class TreeNode<K,V> extends Node<K,V> {
2677	>	TreeNode<K,V> parent;  // red-black tree links
2678	>	TreeNode<K,V> left;
2679	>	TreeNode<K,V> right;
2680	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2681	>	boolean red;
2682	>
2683	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2684	>	TreeNode<K,V> parent) {
2685	>	super(hash, key, val, next);
2686	>	this.parent = parent;
2687	>	}
2688
2689	<	// inherit Map javadoc
2690	<	public boolean isEmpty() {
597	<	/*
598	<	* We need to keep track of per-segment modCounts to avoid ABA
599	<	* problems in which an element in one segment was added and
600	<	* in another removed during traversal, in which case the
601	<	* table was never actually empty at any point. Note the
602	<	* similar use of modCounts in the size() and containsValue()
603	<	* methods, which are the only other methods also susceptible
604	<	* to ABA problems.
605	<	*/
606	<	int[] mc = new int[segments.length];
607	<	int mcsum = 0;
608	<	for (int i = 0; i < segments.length; ++i) {
609	<	if (segments[i].count != 0)
610	<	return false;
611	<	else
612	<	mcsum += mc[i] = segments[i].modCount;
2689	>	Node<K,V> find(int h, Object k) {
2690	>	return findTreeNode(h, k, null);
2691		}
2692	<	// If mcsum happens to be zero, then we know we got a snapshot
2693	<	// before any modifications at all were made.  This is
2694	<	// probably common enough to bother tracking.
2695	<	if (mcsum != 0) {
2696	<	for (int i = 0; i < segments.length; ++i) {
2697	<	if (segments[i].count != 0 ||
2698	<	mc[i] != segments[i].modCount)
2699	<	return false;
2692	>
2693	>	/**
2694	>	* Returns the TreeNode (or null if not found) for the given key
2695	>	* starting at given root.
2696	>	*/
2697	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2698	>	if (k != null) {
2699	>	TreeNode<K,V> p = this;
2700	>	do {
2701	>	int ph, dir; K pk; TreeNode<K,V> q;
2702	>	TreeNode<K,V> pl = p.left, pr = p.right;
2703	>	if ((ph = p.hash) > h)
2704	>	p = pl;
2705	>	else if (ph < h)
2706	>	p = pr;
2707	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2708	>	return p;
2709	>	else if (pl == null)
2710	>	p = pr;
2711	>	else if (pr == null)
2712	>	p = pl;
2713	>	else if ((kc != null ||
2714	>	(kc = comparableClassFor(k)) != null) &&
2715	>	(dir = compareComparables(kc, k, pk)) != 0)
2716	>	p = (dir < 0) ? pl : pr;
2717	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2718	>	return q;
2719	>	else
2720	>	p = pl;
2721	>	} while (p != null);
2722		}
2723	+	return null;
2724		}
624	–	return true;
2725		}
2726
2727	<	// inherit Map javadoc
2728	<	public int size() {
2729	<	int[] mc = new int[segments.length];
2730	<	for (;;) {
2731	<	long sum = 0;
2732	<	int mcsum = 0;
2733	<	for (int i = 0; i < segments.length; ++i) {
2734	<	sum += segments[i].count;
2735	<	mcsum += mc[i] = segments[i].modCount;
2736	<	}
2737	<	int check = 0;
2738	<	if (mcsum != 0) {
2739	<	for (int i = 0; i < segments.length; ++i) {
2740	<	check += segments[i].count;
2741	<	if (mc[i] != segments[i].modCount) {
2742	<	check = -1; // force retry
2743	<	break;
2727	>	/* ---------------- TreeBins -------------- */
2728	>
2729	>	/**
2730	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2731	>	* keys or values, but instead point to list of TreeNodes and
2732	>	* their root. They also maintain a parasitic read-write lock
2733	>	* forcing writers (who hold bin lock) to wait for readers (who do
2734	>	* not) to complete before tree restructuring operations.
2735	>	*/
2736	>	static final class TreeBin<K,V> extends Node<K,V> {
2737	>	TreeNode<K,V> root;
2738	>	volatile TreeNode<K,V> first;
2739	>	volatile Thread waiter;
2740	>	volatile int lockState;
2741	>	// values for lockState
2742	>	static final int WRITER = 1; // set while holding write lock
2743	>	static final int WAITER = 2; // set when waiting for write lock
2744	>	static final int READER = 4; // increment value for setting read lock
2745	>
2746	>	/**
2747	>	* Tie-breaking utility for ordering insertions when equal
2748	>	* hashCodes and non-comparable. We don't require a total
2749	>	* order, just a consistent insertion rule to maintain
2750	>	* equivalence across rebalancings. Tie-breaking further than
2751	>	* necessary simplifies testing a bit.
2752	>	*/
2753	>	static int tieBreakOrder(Object a, Object b) {
2754	>	int d;
2755	>	if (a == null || b == null ||
2756	>	(d = a.getClass().getName().
2757	>	compareTo(b.getClass().getName())) == 0)
2758	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2759	>	-1 : 1);
2760	>	return d;
2761	>	}
2762	>
2763	>	/**
2764	>	* Creates bin with initial set of nodes headed by b.
2765	>	*/
2766	>	TreeBin(TreeNode<K,V> b) {
2767	>	super(TREEBIN, null, null, null);
2768	>	this.first = b;
2769	>	TreeNode<K,V> r = null;
2770	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2771	>	next = (TreeNode<K,V>)x.next;
2772	>	x.left = x.right = null;
2773	>	if (r == null) {
2774	>	x.parent = null;
2775	>	x.red = false;
2776	>	r = x;
2777	>	}
2778	>	else {
2779	>	K k = x.key;
2780	>	int h = x.hash;
2781	>	Class<?> kc = null;
2782	>	for (TreeNode<K,V> p = r;;) {
2783	>	int dir, ph;
2784	>	K pk = p.key;
2785	>	if ((ph = p.hash) > h)
2786	>	dir = -1;
2787	>	else if (ph < h)
2788	>	dir = 1;
2789	>	else if ((kc == null &&
2790	>	(kc = comparableClassFor(k)) == null) ||
2791	>	(dir = compareComparables(kc, k, pk)) == 0)
2792	>	dir = tieBreakOrder(k, pk);
2793	>	TreeNode<K,V> xp = p;
2794	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2795	>	x.parent = xp;
2796	>	if (dir <= 0)
2797	>	xp.left = x;
2798	>	else
2799	>	xp.right = x;
2800	>	r = balanceInsertion(r, x);
2801	>	break;
2802	>	}
2803		}
2804		}
2805		}
2806	<	if (check == sum) {
2807	<	if (sum > Integer.MAX_VALUE)
2808	<	return Integer.MAX_VALUE;
2806	>	this.root = r;
2807	>	assert checkInvariants(root);
2808	>	}
2809	>
2810	>	/**
2811	>	* Acquires write lock for tree restructuring.
2812	>	*/
2813	>	private final void lockRoot() {
2814	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2815	>	contendedLock(); // offload to separate method
2816	>	}
2817	>
2818	>	/**
2819	>	* Releases write lock for tree restructuring.
2820	>	*/
2821	>	private final void unlockRoot() {
2822	>	lockState = 0;
2823	>	}
2824	>
2825	>	/**
2826	>	* Possibly blocks awaiting root lock.
2827	>	*/
2828	>	private final void contendedLock() {
2829	>	boolean waiting = false;
2830	>	for (int s;;) {
2831	>	if (((s = lockState) & ~WAITER) == 0) {
2832	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2833	>	if (waiting)
2834	>	waiter = null;
2835	>	return;
2836	>	}
2837	>	}
2838	>	else if ((s & WAITER) == 0) {
2839	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2840	>	waiting = true;
2841	>	waiter = Thread.currentThread();
2842	>	}
2843	>	}
2844	>	else if (waiting)
2845	>	LockSupport.park(this);
2846	>	}
2847	>	}
2848	>
2849	>	/**
2850	>	* Returns matching node or null if none. Tries to search
2851	>	* using tree comparisons from root, but continues linear
2852	>	* search when lock not available.
2853	>	*/
2854	>	final Node<K,V> find(int h, Object k) {
2855	>	if (k != null) {
2856	>	for (Node<K,V> e = first; e != null; ) {
2857	>	int s; K ek;
2858	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2859	>	if (e.hash == h &&
2860	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2861	>	return e;
2862	>	e = e.next;
2863	>	}
2864	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2865	>	s + READER)) {
2866	>	TreeNode<K,V> r, p;
2867	>	try {
2868	>	p = ((r = root) == null ? null :
2869	>	r.findTreeNode(h, k, null));
2870	>	} finally {
2871	>	Thread w;
2872	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2873	>	(READER|WAITER) && (w = waiter) != null)
2874	>	LockSupport.unpark(w);
2875	>	}
2876	>	return p;
2877	>	}
2878	>	}
2879	>	}
2880	>	return null;
2881	>	}
2882	>
2883	>	/**
2884	>	* Finds or adds a node.
2885	>	* @return null if added
2886	>	*/
2887	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2888	>	Class<?> kc = null;
2889	>	boolean searched = false;
2890	>	for (TreeNode<K,V> p = root;;) {
2891	>	int dir, ph; K pk;
2892	>	if (p == null) {
2893	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2894	>	break;
2895	>	}
2896	>	else if ((ph = p.hash) > h)
2897	>	dir = -1;
2898	>	else if (ph < h)
2899	>	dir = 1;
2900	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2901	>	return p;
2902	>	else if ((kc == null &&
2903	>	(kc = comparableClassFor(k)) == null) ||
2904	>	(dir = compareComparables(kc, k, pk)) == 0) {
2905	>	if (!searched) {
2906	>	TreeNode<K,V> q, ch;
2907	>	searched = true;
2908	>	if (((ch = p.left) != null &&
2909	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2910	>	((ch = p.right) != null &&
2911	>	(q = ch.findTreeNode(h, k, kc)) != null))
2912	>	return q;
2913	>	}
2914	>	dir = tieBreakOrder(k, pk);
2915	>	}
2916	>
2917	>	TreeNode<K,V> xp = p;
2918	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2919	>	TreeNode<K,V> x, f = first;
2920	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2921	>	if (f != null)
2922	>	f.prev = x;
2923	>	if (dir <= 0)
2924	>	xp.left = x;
2925	>	else
2926	>	xp.right = x;
2927	>	if (!xp.red)
2928	>	x.red = true;
2929	>	else {
2930	>	lockRoot();
2931	>	try {
2932	>	root = balanceInsertion(root, x);
2933	>	} finally {
2934	>	unlockRoot();
2935	>	}
2936	>	}
2937	>	break;
2938	>	}
2939	>	}
2940	>	assert checkInvariants(root);
2941	>	return null;
2942	>	}
2943	>
2944	>	/**
2945	>	* Removes the given node, that must be present before this
2946	>	* call.  This is messier than typical red-black deletion code
2947	>	* because we cannot swap the contents of an interior node
2948	>	* with a leaf successor that is pinned by "next" pointers
2949	>	* that are accessible independently of lock. So instead we
2950	>	* swap the tree linkages.
2951	>	*
2952	>	* @return true if now too small, so should be untreeified
2953	>	*/
2954	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2955	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2956	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2957	>	TreeNode<K,V> r, rl;
2958	>	if (pred == null)
2959	>	first = next;
2960	>	else
2961	>	pred.next = next;
2962	>	if (next != null)
2963	>	next.prev = pred;
2964	>	if (first == null) {
2965	>	root = null;
2966	>	return true;
2967	>	}
2968	>	if ((r = root) == null || r.right == null || // too small
2969	>	(rl = r.left) == null || rl.left == null)
2970	>	return true;
2971	>	lockRoot();
2972	>	try {
2973	>	TreeNode<K,V> replacement;
2974	>	TreeNode<K,V> pl = p.left;
2975	>	TreeNode<K,V> pr = p.right;
2976	>	if (pl != null && pr != null) {
2977	>	TreeNode<K,V> s = pr, sl;
2978	>	while ((sl = s.left) != null) // find successor
2979	>	s = sl;
2980	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2981	>	TreeNode<K,V> sr = s.right;
2982	>	TreeNode<K,V> pp = p.parent;
2983	>	if (s == pr) { // p was s's direct parent
2984	>	p.parent = s;
2985	>	s.right = p;
2986	>	}
2987	>	else {
2988	>	TreeNode<K,V> sp = s.parent;
2989	>	if ((p.parent = sp) != null) {
2990	>	if (s == sp.left)
2991	>	sp.left = p;
2992	>	else
2993	>	sp.right = p;
2994	>	}
2995	>	if ((s.right = pr) != null)
2996	>	pr.parent = s;
2997	>	}
2998	>	p.left = null;
2999	>	if ((p.right = sr) != null)
3000	>	sr.parent = p;
3001	>	if ((s.left = pl) != null)
3002	>	pl.parent = s;
3003	>	if ((s.parent = pp) == null)
3004	>	r = s;
3005	>	else if (p == pp.left)
3006	>	pp.left = s;
3007	>	else
3008	>	pp.right = s;
3009	>	if (sr != null)
3010	>	replacement = sr;
3011	>	else
3012	>	replacement = p;
3013	>	}
3014	>	else if (pl != null)
3015	>	replacement = pl;
3016	>	else if (pr != null)
3017	>	replacement = pr;
3018	>	else
3019	>	replacement = p;
3020	>	if (replacement != p) {
3021	>	TreeNode<K,V> pp = replacement.parent = p.parent;
3022	>	if (pp == null)
3023	>	r = replacement;
3024	>	else if (p == pp.left)
3025	>	pp.left = replacement;
3026	>	else
3027	>	pp.right = replacement;
3028	>	p.left = p.right = p.parent = null;
3029	>	}
3030	>
3031	>	root = (p.red) ? r : balanceDeletion(r, replacement);
3032	>
3033	>	if (p == replacement) {  // detach pointers
3034	>	TreeNode<K,V> pp;
3035	>	if ((pp = p.parent) != null) {
3036	>	if (p == pp.left)
3037	>	pp.left = null;
3038	>	else if (p == pp.right)
3039	>	pp.right = null;
3040	>	p.parent = null;
3041	>	}
3042	>	}
3043	>	} finally {
3044	>	unlockRoot();
3045	>	}
3046	>	assert checkInvariants(root);
3047	>	return false;
3048	>	}
3049	>
3050	>	/* ------------------------------------------------------------ */
3051	>	// Red-black tree methods, all adapted from CLR
3052	>
3053	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3054	>	TreeNode<K,V> p) {
3055	>	TreeNode<K,V> r, pp, rl;
3056	>	if (p != null && (r = p.right) != null) {
3057	>	if ((rl = p.right = r.left) != null)
3058	>	rl.parent = p;
3059	>	if ((pp = r.parent = p.parent) == null)
3060	>	(root = r).red = false;
3061	>	else if (pp.left == p)
3062	>	pp.left = r;
3063	>	else
3064	>	pp.right = r;
3065	>	r.left = p;
3066	>	p.parent = r;
3067	>	}
3068	>	return root;
3069	>	}
3070	>
3071	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3072	>	TreeNode<K,V> p) {
3073	>	TreeNode<K,V> l, pp, lr;
3074	>	if (p != null && (l = p.left) != null) {
3075	>	if ((lr = p.left = l.right) != null)
3076	>	lr.parent = p;
3077	>	if ((pp = l.parent = p.parent) == null)
3078	>	(root = l).red = false;
3079	>	else if (pp.right == p)
3080	>	pp.right = l;
3081		else
3082	<	return (int)sum;
3082	>	pp.left = l;
3083	>	l.right = p;
3084	>	p.parent = l;
3085	>	}
3086	>	return root;
3087	>	}
3088	>
3089	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3090	>	TreeNode<K,V> x) {
3091	>	x.red = true;
3092	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3093	>	if ((xp = x.parent) == null) {
3094	>	x.red = false;
3095	>	return x;
3096	>	}
3097	>	else if (!xp.red || (xpp = xp.parent) == null)
3098	>	return root;
3099	>	if (xp == (xppl = xpp.left)) {
3100	>	if ((xppr = xpp.right) != null && xppr.red) {
3101	>	xppr.red = false;
3102	>	xp.red = false;
3103	>	xpp.red = true;
3104	>	x = xpp;
3105	>	}
3106	>	else {
3107	>	if (x == xp.right) {
3108	>	root = rotateLeft(root, x = xp);
3109	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3110	>	}
3111	>	if (xp != null) {
3112	>	xp.red = false;
3113	>	if (xpp != null) {
3114	>	xpp.red = true;
3115	>	root = rotateRight(root, xpp);
3116	>	}
3117	>	}
3118	>	}
3119	>	}
3120	>	else {
3121	>	if (xppl != null && xppl.red) {
3122	>	xppl.red = false;
3123	>	xp.red = false;
3124	>	xpp.red = true;
3125	>	x = xpp;
3126	>	}
3127	>	else {
3128	>	if (x == xp.left) {
3129	>	root = rotateRight(root, x = xp);
3130	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3131	>	}
3132	>	if (xp != null) {
3133	>	xp.red = false;
3134	>	if (xpp != null) {
3135	>	xpp.red = true;
3136	>	root = rotateLeft(root, xpp);
3137	>	}
3138	>	}
3139	>	}
3140	>	}
3141	>	}
3142	>	}
3143	>
3144	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3145	>	TreeNode<K,V> x) {
3146	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3147	>	if (x == null || x == root)
3148	>	return root;
3149	>	else if ((xp = x.parent) == null) {
3150	>	x.red = false;
3151	>	return x;
3152	>	}
3153	>	else if (x.red) {
3154	>	x.red = false;
3155	>	return root;
3156	>	}
3157	>	else if ((xpl = xp.left) == x) {
3158	>	if ((xpr = xp.right) != null && xpr.red) {
3159	>	xpr.red = false;
3160	>	xp.red = true;
3161	>	root = rotateLeft(root, xp);
3162	>	xpr = (xp = x.parent) == null ? null : xp.right;
3163	>	}
3164	>	if (xpr == null)
3165	>	x = xp;
3166	>	else {
3167	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3168	>	if ((sr == null || !sr.red) &&
3169	>	(sl == null || !sl.red)) {
3170	>	xpr.red = true;
3171	>	x = xp;
3172	>	}
3173	>	else {
3174	>	if (sr == null || !sr.red) {
3175	>	if (sl != null)
3176	>	sl.red = false;
3177	>	xpr.red = true;
3178	>	root = rotateRight(root, xpr);
3179	>	xpr = (xp = x.parent) == null ?
3180	>	null : xp.right;
3181	>	}
3182	>	if (xpr != null) {
3183	>	xpr.red = (xp == null) ? false : xp.red;
3184	>	if ((sr = xpr.right) != null)
3185	>	sr.red = false;
3186	>	}
3187	>	if (xp != null) {
3188	>	xp.red = false;
3189	>	root = rotateLeft(root, xp);
3190	>	}
3191	>	x = root;
3192	>	}
3193	>	}
3194	>	}
3195	>	else { // symmetric
3196	>	if (xpl != null && xpl.red) {
3197	>	xpl.red = false;
3198	>	xp.red = true;
3199	>	root = rotateRight(root, xp);
3200	>	xpl = (xp = x.parent) == null ? null : xp.left;
3201	>	}
3202	>	if (xpl == null)
3203	>	x = xp;
3204	>	else {
3205	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3206	>	if ((sl == null || !sl.red) &&
3207	>	(sr == null || !sr.red)) {
3208	>	xpl.red = true;
3209	>	x = xp;
3210	>	}
3211	>	else {
3212	>	if (sl == null || !sl.red) {
3213	>	if (sr != null)
3214	>	sr.red = false;
3215	>	xpl.red = true;
3216	>	root = rotateLeft(root, xpl);
3217	>	xpl = (xp = x.parent) == null ?
3218	>	null : xp.left;
3219	>	}
3220	>	if (xpl != null) {
3221	>	xpl.red = (xp == null) ? false : xp.red;
3222	>	if ((sl = xpl.left) != null)
3223	>	sl.red = false;
3224	>	}
3225	>	if (xp != null) {
3226	>	xp.red = false;
3227	>	root = rotateRight(root, xp);
3228	>	}
3229	>	x = root;
3230	>	}
3231	>	}
3232	>	}
3233	>	}
3234	>	}
3235	>
3236	>	/**
3237	>	* Recursive invariant check
3238	>	*/
3239	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3240	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3241	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3242	>	if (tb != null && tb.next != t)
3243	>	return false;
3244	>	if (tn != null && tn.prev != t)
3245	>	return false;
3246	>	if (tp != null && t != tp.left && t != tp.right)
3247	>	return false;
3248	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3249	>	return false;
3250	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3251	>	return false;
3252	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3253	>	return false;
3254	>	if (tl != null && !checkInvariants(tl))
3255	>	return false;
3256	>	if (tr != null && !checkInvariants(tr))
3257	>	return false;
3258	>	return true;
3259	>	}
3260	>
3261	>	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
3262	>	private static final long LOCKSTATE;
3263	>	static {
3264	>	try {
3265	>	LOCKSTATE = U.objectFieldOffset
3266	>	(TreeBin.class.getDeclaredField("lockState"));
3267	>	} catch (ReflectiveOperationException e) {
3268	>	throw new Error(e);
3269		}
3270		}
3271		}
3272
3273	+	/* ----------------Table Traversal -------------- */
3274	+
3275	+	/**
3276	+	* Records the table, its length, and current traversal index for a
3277	+	* traverser that must process a region of a forwarded table before
3278	+	* proceeding with current table.
3279	+	*/
3280	+	static final class TableStack<K,V> {
3281	+	int length;
3282	+	int index;
3283	+	Node<K,V>[] tab;
3284	+	TableStack<K,V> next;
3285	+	}
3286
3287		/**
3288	<	* Returns the value to which the specified key is mapped in this table.
3288	>	* Encapsulates traversal for methods such as containsValue; also
3289	>	* serves as a base class for other iterators and spliterators.
3290	>	*
3291	>	* Method advance visits once each still-valid node that was
3292	>	* reachable upon iterator construction. It might miss some that
3293	>	* were added to a bin after the bin was visited, which is OK wrt
3294	>	* consistency guarantees. Maintaining this property in the face
3295	>	* of possible ongoing resizes requires a fair amount of
3296	>	* bookkeeping state that is difficult to optimize away amidst
3297	>	* volatile accesses.  Even so, traversal maintains reasonable
3298	>	* throughput.
3299		*
3300	<	* @param   key   a key in the table.
3301	<	* @return  the value to which the key is mapped in this table;
3302	<	*          <tt>null</tt> if the key is not mapped to any value in
3303	<	*          this table.
3304	<	* @throws  NullPointerException  if the key is
3305	<	*               <tt>null</tt>.
3300	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3301	>	* However, if the table has been resized, then all future steps
3302	>	* must traverse both the bin at the current index as well as at
3303	>	* (index + baseSize); and so on for further resizings. To
3304	>	* paranoically cope with potential sharing by users of iterators
3305	>	* across threads, iteration terminates if a bounds checks fails
3306	>	* for a table read.
3307		*/
3308	<	public V get(Object key) {
3309	<	int hash = hash(key); // throws NullPointerException if key null
3310	<	return segmentFor(hash).get(key, hash);
3308	>	static class Traverser<K,V> {
3309	>	Node<K,V>[] tab;        // current table; updated if resized
3310	>	Node<K,V> next;         // the next entry to use
3311	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3312	>	int index;              // index of bin to use next
3313	>	int baseIndex;          // current index of initial table
3314	>	int baseLimit;          // index bound for initial table
3315	>	final int baseSize;     // initial table size
3316	>
3317	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3318	>	this.tab = tab;
3319	>	this.baseSize = size;
3320	>	this.baseIndex = this.index = index;
3321	>	this.baseLimit = limit;
3322	>	this.next = null;
3323	>	}
3324	>
3325	>	/**
3326	>	* Advances if possible, returning next valid node, or null if none.
3327	>	*/
3328	>	final Node<K,V> advance() {
3329	>	Node<K,V> e;
3330	>	if ((e = next) != null)
3331	>	e = e.next;
3332	>	for (;;) {
3333	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3334	>	if (e != null)
3335	>	return next = e;
3336	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3337	>	(n = t.length) <= (i = index) || i < 0)
3338	>	return next = null;
3339	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3340	>	if (e instanceof ForwardingNode) {
3341	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3342	>	e = null;
3343	>	pushState(t, i, n);
3344	>	continue;
3345	>	}
3346	>	else if (e instanceof TreeBin)
3347	>	e = ((TreeBin<K,V>)e).first;
3348	>	else
3349	>	e = null;
3350	>	}
3351	>	if (stack != null)
3352	>	recoverState(n);
3353	>	else if ((index = i + baseSize) >= n)
3354	>	index = ++baseIndex; // visit upper slots if present
3355	>	}
3356	>	}
3357	>
3358	>	/**
3359	>	* Saves traversal state upon encountering a forwarding node.
3360	>	*/
3361	>	private void pushState(Node<K,V>[] t, int i, int n) {
3362	>	TableStack<K,V> s = spare;  // reuse if possible
3363	>	if (s != null)
3364	>	spare = s.next;
3365	>	else
3366	>	s = new TableStack<K,V>();
3367	>	s.tab = t;
3368	>	s.length = n;
3369	>	s.index = i;
3370	>	s.next = stack;
3371	>	stack = s;
3372	>	}
3373	>
3374	>	/**
3375	>	* Possibly pops traversal state.
3376	>	*
3377	>	* @param n length of current table
3378	>	*/
3379	>	private void recoverState(int n) {
3380	>	TableStack<K,V> s; int len;
3381	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3382	>	n = len;
3383	>	index = s.index;
3384	>	tab = s.tab;
3385	>	s.tab = null;
3386	>	TableStack<K,V> next = s.next;
3387	>	s.next = spare; // save for reuse
3388	>	stack = next;
3389	>	spare = s;
3390	>	}
3391	>	if (s == null && (index += baseSize) >= n)
3392	>	index = ++baseIndex;
3393	>	}
3394		}
3395
3396		/**
3397	<	* Tests if the specified object is a key in this table.
3397	>	* Base of key, value, and entry Iterators. Adds fields to
3398	>	* Traverser to support iterator.remove.
3399	>	*/
3400	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3401	>	final ConcurrentHashMap<K,V> map;
3402	>	Node<K,V> lastReturned;
3403	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3404	>	ConcurrentHashMap<K,V> map) {
3405	>	super(tab, size, index, limit);
3406	>	this.map = map;
3407	>	advance();
3408	>	}
3409	>
3410	>	public final boolean hasNext() { return next != null; }
3411	>	public final boolean hasMoreElements() { return next != null; }
3412	>
3413	>	public final void remove() {
3414	>	Node<K,V> p;
3415	>	if ((p = lastReturned) == null)
3416	>	throw new IllegalStateException();
3417	>	lastReturned = null;
3418	>	map.replaceNode(p.key, null, null);
3419	>	}
3420	>	}
3421	>
3422	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3423	>	implements Iterator<K>, Enumeration<K> {
3424	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3425	>	ConcurrentHashMap<K,V> map) {
3426	>	super(tab, index, size, limit, map);
3427	>	}
3428	>
3429	>	public final K next() {
3430	>	Node<K,V> p;
3431	>	if ((p = next) == null)
3432	>	throw new NoSuchElementException();
3433	>	K k = p.key;
3434	>	lastReturned = p;
3435	>	advance();
3436	>	return k;
3437	>	}
3438	>
3439	>	public final K nextElement() { return next(); }
3440	>	}
3441	>
3442	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3443	>	implements Iterator<V>, Enumeration<V> {
3444	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3445	>	ConcurrentHashMap<K,V> map) {
3446	>	super(tab, index, size, limit, map);
3447	>	}
3448	>
3449	>	public final V next() {
3450	>	Node<K,V> p;
3451	>	if ((p = next) == null)
3452	>	throw new NoSuchElementException();
3453	>	V v = p.val;
3454	>	lastReturned = p;
3455	>	advance();
3456	>	return v;
3457	>	}
3458	>
3459	>	public final V nextElement() { return next(); }
3460	>	}
3461	>
3462	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3463	>	implements Iterator<Map.Entry<K,V>> {
3464	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3465	>	ConcurrentHashMap<K,V> map) {
3466	>	super(tab, index, size, limit, map);
3467	>	}
3468	>
3469	>	public final Map.Entry<K,V> next() {
3470	>	Node<K,V> p;
3471	>	if ((p = next) == null)
3472	>	throw new NoSuchElementException();
3473	>	K k = p.key;
3474	>	V v = p.val;
3475	>	lastReturned = p;
3476	>	advance();
3477	>	return new MapEntry<K,V>(k, v, map);
3478	>	}
3479	>	}
3480	>
3481	>	/**
3482	>	* Exported Entry for EntryIterator
3483	>	*/
3484	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3485	>	final K key; // non-null
3486	>	V val;       // non-null
3487	>	final ConcurrentHashMap<K,V> map;
3488	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3489	>	this.key = key;
3490	>	this.val = val;
3491	>	this.map = map;
3492	>	}
3493	>	public K getKey()        { return key; }
3494	>	public V getValue()      { return val; }
3495	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3496	>	public String toString() {
3497	>	return Helpers.mapEntryToString(key, val);
3498	>	}
3499	>
3500	>	public boolean equals(Object o) {
3501	>	Object k, v; Map.Entry<?,?> e;
3502	>	return ((o instanceof Map.Entry) &&
3503	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3504	>	(v = e.getValue()) != null &&
3505	>	(k == key || k.equals(key)) &&
3506	>	(v == val || v.equals(val)));
3507	>	}
3508	>
3509	>	/**
3510	>	* Sets our entry's value and writes through to the map. The
3511	>	* value to return is somewhat arbitrary here. Since we do not
3512	>	* necessarily track asynchronous changes, the most recent
3513	>	* "previous" value could be different from what we return (or
3514	>	* could even have been removed, in which case the put will
3515	>	* re-establish). We do not and cannot guarantee more.
3516	>	*/
3517	>	public V setValue(V value) {
3518	>	if (value == null) throw new NullPointerException();
3519	>	V v = val;
3520	>	val = value;
3521	>	map.put(key, value);
3522	>	return v;
3523	>	}
3524	>	}
3525	>
3526	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3527	>	implements Spliterator<K> {
3528	>	long est;               // size estimate
3529	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3530	>	long est) {
3531	>	super(tab, size, index, limit);
3532	>	this.est = est;
3533	>	}
3534	>
3535	>	public Spliterator<K> trySplit() {
3536	>	int i, f, h;
3537	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3538	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3539	>	f, est >>>= 1);
3540	>	}
3541	>
3542	>	public void forEachRemaining(Consumer<? super K> action) {
3543	>	if (action == null) throw new NullPointerException();
3544	>	for (Node<K,V> p; (p = advance()) != null;)
3545	>	action.accept(p.key);
3546	>	}
3547	>
3548	>	public boolean tryAdvance(Consumer<? super K> action) {
3549	>	if (action == null) throw new NullPointerException();
3550	>	Node<K,V> p;
3551	>	if ((p = advance()) == null)
3552	>	return false;
3553	>	action.accept(p.key);
3554	>	return true;
3555	>	}
3556	>
3557	>	public long estimateSize() { return est; }
3558	>
3559	>	public int characteristics() {
3560	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3561	>	Spliterator.NONNULL;
3562	>	}
3563	>	}
3564	>
3565	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3566	>	implements Spliterator<V> {
3567	>	long est;               // size estimate
3568	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3569	>	long est) {
3570	>	super(tab, size, index, limit);
3571	>	this.est = est;
3572	>	}
3573	>
3574	>	public Spliterator<V> trySplit() {
3575	>	int i, f, h;
3576	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3577	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3578	>	f, est >>>= 1);
3579	>	}
3580	>
3581	>	public void forEachRemaining(Consumer<? super V> action) {
3582	>	if (action == null) throw new NullPointerException();
3583	>	for (Node<K,V> p; (p = advance()) != null;)
3584	>	action.accept(p.val);
3585	>	}
3586	>
3587	>	public boolean tryAdvance(Consumer<? super V> action) {
3588	>	if (action == null) throw new NullPointerException();
3589	>	Node<K,V> p;
3590	>	if ((p = advance()) == null)
3591	>	return false;
3592	>	action.accept(p.val);
3593	>	return true;
3594	>	}
3595	>
3596	>	public long estimateSize() { return est; }
3597	>
3598	>	public int characteristics() {
3599	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3600	>	}
3601	>	}
3602	>
3603	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3604	>	implements Spliterator<Map.Entry<K,V>> {
3605	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3606	>	long est;               // size estimate
3607	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3608	>	long est, ConcurrentHashMap<K,V> map) {
3609	>	super(tab, size, index, limit);
3610	>	this.map = map;
3611	>	this.est = est;
3612	>	}
3613	>
3614	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3615	>	int i, f, h;
3616	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3617	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3618	>	f, est >>>= 1, map);
3619	>	}
3620	>
3621	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3622	>	if (action == null) throw new NullPointerException();
3623	>	for (Node<K,V> p; (p = advance()) != null; )
3624	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3625	>	}
3626	>
3627	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3628	>	if (action == null) throw new NullPointerException();
3629	>	Node<K,V> p;
3630	>	if ((p = advance()) == null)
3631	>	return false;
3632	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3633	>	return true;
3634	>	}
3635	>
3636	>	public long estimateSize() { return est; }
3637	>
3638	>	public int characteristics() {
3639	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3640	>	Spliterator.NONNULL;
3641	>	}
3642	>	}
3643	>
3644	>	// Parallel bulk operations
3645	>
3646	>	/**
3647	>	* Computes initial batch value for bulk tasks. The returned value
3648	>	* is approximately exp2 of the number of times (minus one) to
3649	>	* split task by two before executing leaf action. This value is
3650	>	* faster to compute and more convenient to use as a guide to
3651	>	* splitting than is the depth, since it is used while dividing by
3652	>	* two anyway.
3653	>	*/
3654	>	final int batchFor(long b) {
3655	>	long n;
3656	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3657	>	return 0;
3658	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3659	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3660	>	}
3661	>
3662	>	/**
3663	>	* Performs the given action for each (key, value).
3664		*
3665	<	* @param   key   possible key.
3666	<	* @return  <tt>true</tt> if and only if the specified object
3667	<	*          is a key in this table, as determined by the
3668	<	*          <tt>equals</tt> method; <tt>false</tt> otherwise.
679	<	* @throws  NullPointerException  if the key is
680	<	*               <tt>null</tt>.
3665	>	* @param parallelismThreshold the (estimated) number of elements
3666	>	* needed for this operation to be executed in parallel
3667	>	* @param action the action
3668	>	* @since 1.8
3669		*/
3670	<	public boolean containsKey(Object key) {
3671	<	int hash = hash(key); // throws NullPointerException if key null
3672	<	return segmentFor(hash).containsKey(key, hash);
3670	>	public void forEach(long parallelismThreshold,
3671	>	BiConsumer<? super K,? super V> action) {
3672	>	if (action == null) throw new NullPointerException();
3673	>	new ForEachMappingTask<K,V>
3674	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3675	>	action).invoke();
3676		}
3677
3678		/**
3679	<	* Returns <tt>true</tt> if this map maps one or more keys to the
3680	<	* specified value. Note: This method requires a full internal
690	<	* traversal of the hash table, and so is much slower than
691	<	* method <tt>containsKey</tt>.
3679	>	* Performs the given action for each non-null transformation
3680	>	* of each (key, value).
3681		*
3682	<	* @param value value whose presence in this map is to be tested.
3683	<	* @return <tt>true</tt> if this map maps one or more keys to the
3684	<	* specified value.
3685	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3682	>	* @param parallelismThreshold the (estimated) number of elements
3683	>	* needed for this operation to be executed in parallel
3684	>	* @param transformer a function returning the transformation
3685	>	* for an element, or null if there is no transformation (in
3686	>	* which case the action is not applied)
3687	>	* @param action the action
3688	>	* @param <U> the return type of the transformer
3689	>	* @since 1.8
3690		*/
3691	<	public boolean containsValue(Object value) {
3692	<	if (value == null)
3691	>	public <U> void forEach(long parallelismThreshold,
3692	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3693	>	Consumer<? super U> action) {
3694	>	if (transformer == null || action == null)
3695		throw new NullPointerException();
3696	+	new ForEachTransformedMappingTask<K,V,U>
3697	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3698	+	transformer, action).invoke();
3699	+	}
3700
3701	<	int[] mc = new int[segments.length];
3702	<	for (;;) {
3703	<	int sum = 0;
3704	<	int mcsum = 0;
3705	<	for (int i = 0; i < segments.length; ++i) {
3706	<	int c = segments[i].count;
3707	<	mcsum += mc[i] = segments[i].modCount;
3708	<	if (segments[i].containsValue(value))
3709	<	return true;
3710	<	}
3711	<	boolean cleanSweep = true;
3712	<	if (mcsum != 0) {
3713	<	for (int i = 0; i < segments.length; ++i) {
3714	<	int c = segments[i].count;
3715	<	if (mc[i] != segments[i].modCount) {
3716	<	cleanSweep = false;
3717	<	break;
3718	<	}
3719	<	}
3720	<	}
3721	<	if (cleanSweep)
3722	<	return false;
724	<	}
3701	>	/**
3702	>	* Returns a non-null result from applying the given search
3703	>	* function on each (key, value), or null if none.  Upon
3704	>	* success, further element processing is suppressed and the
3705	>	* results of any other parallel invocations of the search
3706	>	* function are ignored.
3707	>	*
3708	>	* @param parallelismThreshold the (estimated) number of elements
3709	>	* needed for this operation to be executed in parallel
3710	>	* @param searchFunction a function returning a non-null
3711	>	* result on success, else null
3712	>	* @param <U> the return type of the search function
3713	>	* @return a non-null result from applying the given search
3714	>	* function on each (key, value), or null if none
3715	>	* @since 1.8
3716	>	*/
3717	>	public <U> U search(long parallelismThreshold,
3718	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3719	>	if (searchFunction == null) throw new NullPointerException();
3720	>	return new SearchMappingsTask<K,V,U>
3721	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3722	>	searchFunction, new AtomicReference<U>()).invoke();
3723		}
3724
3725		/**
3726	<	* Legacy method testing if some key maps into the specified value
3727	<	* in this table.  This method is identical in functionality to
3728	<	* {@link #containsValue}, and  exists solely to ensure
3729	<	* full compatibility with class {@link java.util.Hashtable},
3730	<	* which supported this method prior to introduction of the
3731	<	* Java Collections framework.
3726	>	* Returns the result of accumulating the given transformation
3727	>	* of all (key, value) pairs using the given reducer to
3728	>	* combine values, or null if none.
3729	>	*
3730	>	* @param parallelismThreshold the (estimated) number of elements
3731	>	* needed for this operation to be executed in parallel
3732	>	* @param transformer a function returning the transformation
3733	>	* for an element, or null if there is no transformation (in
3734	>	* which case it is not combined)
3735	>	* @param reducer a commutative associative combining function
3736	>	* @param <U> the return type of the transformer
3737	>	* @return the result of accumulating the given transformation
3738	>	* of all (key, value) pairs
3739	>	* @since 1.8
3740	>	*/
3741	>	public <U> U reduce(long parallelismThreshold,
3742	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3743	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3744	>	if (transformer == null || reducer == null)
3745	>	throw new NullPointerException();
3746	>	return new MapReduceMappingsTask<K,V,U>
3747	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3748	>	null, transformer, reducer).invoke();
3749	>	}
3750
3751	<	* @param      value   a value to search for.
3752	<	* @return     <tt>true</tt> if and only if some key maps to the
3753	<	*             <tt>value</tt> argument in this table as
3754	<	*             determined by the <tt>equals</tt> method;
3755	<	*             <tt>false</tt> otherwise.
3756	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3751	>	/**
3752	>	* Returns the result of accumulating the given transformation
3753	>	* of all (key, value) pairs using the given reducer to
3754	>	* combine values, and the given basis as an identity value.
3755	>	*
3756	>	* @param parallelismThreshold the (estimated) number of elements
3757	>	* needed for this operation to be executed in parallel
3758	>	* @param transformer a function returning the transformation
3759	>	* for an element
3760	>	* @param basis the identity (initial default value) for the reduction
3761	>	* @param reducer a commutative associative combining function
3762	>	* @return the result of accumulating the given transformation
3763	>	* of all (key, value) pairs
3764	>	* @since 1.8
3765		*/
3766	<	public boolean contains(Object value) {
3767	<	return containsValue(value);
3766	>	public double reduceToDouble(long parallelismThreshold,
3767	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3768	>	double basis,
3769	>	DoubleBinaryOperator reducer) {
3770	>	if (transformer == null || reducer == null)
3771	>	throw new NullPointerException();
3772	>	return new MapReduceMappingsToDoubleTask<K,V>
3773	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3774	>	null, transformer, basis, reducer).invoke();
3775		}
3776
3777		/**
3778	<	* Maps the specified <tt>key</tt> to the specified
3779	<	* <tt>value</tt> in this table. Neither the key nor the
3780	<	* value can be <tt>null</tt>. <p>
3778	>	* Returns the result of accumulating the given transformation
3779	>	* of all (key, value) pairs using the given reducer to
3780	>	* combine values, and the given basis as an identity value.
3781		*
3782	<	* The value can be retrieved by calling the <tt>get</tt> method
3783	<	* with a key that is equal to the original key.
3782	>	* @param parallelismThreshold the (estimated) number of elements
3783	>	* needed for this operation to be executed in parallel
3784	>	* @param transformer a function returning the transformation
3785	>	* for an element
3786	>	* @param basis the identity (initial default value) for the reduction
3787	>	* @param reducer a commutative associative combining function
3788	>	* @return the result of accumulating the given transformation
3789	>	* of all (key, value) pairs
3790	>	* @since 1.8
3791	>	*/
3792	>	public long reduceToLong(long parallelismThreshold,
3793	>	ToLongBiFunction<? super K, ? super V> transformer,
3794	>	long basis,
3795	>	LongBinaryOperator reducer) {
3796	>	if (transformer == null || reducer == null)
3797	>	throw new NullPointerException();
3798	>	return new MapReduceMappingsToLongTask<K,V>
3799	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3800	>	null, transformer, basis, reducer).invoke();
3801	>	}
3802	>
3803	>	/**
3804	>	* Returns the result of accumulating the given transformation
3805	>	* of all (key, value) pairs using the given reducer to
3806	>	* combine values, and the given basis as an identity value.
3807		*
3808	<	* @param      key     the table key.
3809	<	* @param      value   the value.
3810	<	* @return     the previous value of the specified key in this table,
3811	<	*             or <tt>null</tt> if it did not have one.
3812	<	* @throws  NullPointerException  if the key or value is
3813	<	*               <tt>null</tt>.
3808	>	* @param parallelismThreshold the (estimated) number of elements
3809	>	* needed for this operation to be executed in parallel
3810	>	* @param transformer a function returning the transformation
3811	>	* for an element
3812	>	* @param basis the identity (initial default value) for the reduction
3813	>	* @param reducer a commutative associative combining function
3814	>	* @return the result of accumulating the given transformation
3815	>	* of all (key, value) pairs
3816	>	* @since 1.8
3817		*/
3818	<	public V put(K key, V value) {
3819	<	if (value == null)
3818	>	public int reduceToInt(long parallelismThreshold,
3819	>	ToIntBiFunction<? super K, ? super V> transformer,
3820	>	int basis,
3821	>	IntBinaryOperator reducer) {
3822	>	if (transformer == null || reducer == null)
3823		throw new NullPointerException();
3824	<	int hash = hash(key);
3825	<	return segmentFor(hash).put(key, hash, value, false);
3824	>	return new MapReduceMappingsToIntTask<K,V>
3825	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3826	>	null, transformer, basis, reducer).invoke();
3827		}
3828
3829		/**
3830	<	* If the specified key is not already associated
770	<	* with a value, associate it with the given value.
771	<	* This is equivalent to
772	<	* <pre>
773	<	*   if (!map.containsKey(key))
774	<	*      return map.put(key, value);
775	<	*   else
776	<	*      return map.get(key);
777	<	* </pre>
778	<	* Except that the action is performed atomically.
779	<	* @param key key with which the specified value is to be associated.
780	<	* @param value value to be associated with the specified key.
781	<	* @return previous value associated with specified key, or <tt>null</tt>
782	<	*         if there was no mapping for key.  A <tt>null</tt> return can
783	<	*         also indicate that the map previously associated <tt>null</tt>
784	<	*         with the specified key, if the implementation supports
785	<	*         <tt>null</tt> values.
786	<	*
787	<	* @throws UnsupportedOperationException if the <tt>put</tt> operation is
788	<	*            not supported by this map.
789	<	* @throws ClassCastException if the class of the specified key or value
790	<	*            prevents it from being stored in this map.
791	<	* @throws NullPointerException if the specified key or value is
792	<	*            <tt>null</tt>.
3830	>	* Performs the given action for each key.
3831		*
3832	<	**/
3833	<	public V putIfAbsent(K key, V value) {
3834	<	if (value == null)
3832	>	* @param parallelismThreshold the (estimated) number of elements
3833	>	* needed for this operation to be executed in parallel
3834	>	* @param action the action
3835	>	* @since 1.8
3836	>	*/
3837	>	public void forEachKey(long parallelismThreshold,
3838	>	Consumer<? super K> action) {
3839	>	if (action == null) throw new NullPointerException();
3840	>	new ForEachKeyTask<K,V>
3841	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3842	>	action).invoke();
3843	>	}
3844	>
3845	>	/**
3846	>	* Performs the given action for each non-null transformation
3847	>	* of each key.
3848	>	*
3849	>	* @param parallelismThreshold the (estimated) number of elements
3850	>	* needed for this operation to be executed in parallel
3851	>	* @param transformer a function returning the transformation
3852	>	* for an element, or null if there is no transformation (in
3853	>	* which case the action is not applied)
3854	>	* @param action the action
3855	>	* @param <U> the return type of the transformer
3856	>	* @since 1.8
3857	>	*/
3858	>	public <U> void forEachKey(long parallelismThreshold,
3859	>	Function<? super K, ? extends U> transformer,
3860	>	Consumer<? super U> action) {
3861	>	if (transformer == null || action == null)
3862		throw new NullPointerException();
3863	<	int hash = hash(key);
3864	<	return segmentFor(hash).put(key, hash, value, true);
3863	>	new ForEachTransformedKeyTask<K,V,U>
3864	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3865	>	transformer, action).invoke();
3866		}
3867
3868	+	/**
3869	+	* Returns a non-null result from applying the given search
3870	+	* function on each key, or null if none. Upon success,
3871	+	* further element processing is suppressed and the results of
3872	+	* any other parallel invocations of the search function are
3873	+	* ignored.
3874	+	*
3875	+	* @param parallelismThreshold the (estimated) number of elements
3876	+	* needed for this operation to be executed in parallel
3877	+	* @param searchFunction a function returning a non-null
3878	+	* result on success, else null
3879	+	* @param <U> the return type of the search function
3880	+	* @return a non-null result from applying the given search
3881	+	* function on each key, or null if none
3882	+	* @since 1.8
3883	+	*/
3884	+	public <U> U searchKeys(long parallelismThreshold,
3885	+	Function<? super K, ? extends U> searchFunction) {
3886	+	if (searchFunction == null) throw new NullPointerException();
3887	+	return new SearchKeysTask<K,V,U>
3888	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3889	+	searchFunction, new AtomicReference<U>()).invoke();
3890	+	}
3891
3892		/**
3893	<	* Copies all of the mappings from the specified map to this one.
3893	>	* Returns the result of accumulating all keys using the given
3894	>	* reducer to combine values, or null if none.
3895		*
3896	<	* These mappings replace any mappings that this map had for any of the
3897	<	* keys currently in the specified Map.
3896	>	* @param parallelismThreshold the (estimated) number of elements
3897	>	* needed for this operation to be executed in parallel
3898	>	* @param reducer a commutative associative combining function
3899	>	* @return the result of accumulating all keys using the given
3900	>	* reducer to combine values, or null if none
3901	>	* @since 1.8
3902	>	*/
3903	>	public K reduceKeys(long parallelismThreshold,
3904	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3905	>	if (reducer == null) throw new NullPointerException();
3906	>	return new ReduceKeysTask<K,V>
3907	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3908	>	null, reducer).invoke();
3909	>	}
3910	>
3911	>	/**
3912	>	* Returns the result of accumulating the given transformation
3913	>	* of all keys using the given reducer to combine values, or
3914	>	* null if none.
3915		*
3916	<	* @param t Mappings to be stored in this map.
3916	>	* @param parallelismThreshold the (estimated) number of elements
3917	>	* needed for this operation to be executed in parallel
3918	>	* @param transformer a function returning the transformation
3919	>	* for an element, or null if there is no transformation (in
3920	>	* which case it is not combined)
3921	>	* @param reducer a commutative associative combining function
3922	>	* @param <U> the return type of the transformer
3923	>	* @return the result of accumulating the given transformation
3924	>	* of all keys
3925	>	* @since 1.8
3926		*/
3927	<	public void putAll(Map<? extends K, ? extends V> t) {
3928	<	for (Iterator<Map.Entry<? extends K, ? extends V>> it = (Iterator<Map.Entry<? extends K, ? extends V>>) t.entrySet().iterator(); it.hasNext(); ) {
3929	<	Entry<? extends K, ? extends V> e = it.next();
3930	<	put(e.getKey(), e.getValue());
3931	<	}
3927	>	public <U> U reduceKeys(long parallelismThreshold,
3928	>	Function<? super K, ? extends U> transformer,
3929	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3930	>	if (transformer == null || reducer == null)
3931	>	throw new NullPointerException();
3932	>	return new MapReduceKeysTask<K,V,U>
3933	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3934	>	null, transformer, reducer).invoke();
3935		}
3936
3937		/**
3938	<	* Removes the key (and its corresponding value) from this
3939	<	* table. This method does nothing if the key is not in the table.
3938	>	* Returns the result of accumulating the given transformation
3939	>	* of all keys using the given reducer to combine values, and
3940	>	* the given basis as an identity value.
3941		*
3942	<	* @param   key   the key that needs to be removed.
3943	<	* @return  the value to which the key had been mapped in this table,
3944	<	*          or <tt>null</tt> if the key did not have a mapping.
3945	<	* @throws  NullPointerException  if the key is
3946	<	*               <tt>null</tt>.
3942	>	* @param parallelismThreshold the (estimated) number of elements
3943	>	* needed for this operation to be executed in parallel
3944	>	* @param transformer a function returning the transformation
3945	>	* for an element
3946	>	* @param basis the identity (initial default value) for the reduction
3947	>	* @param reducer a commutative associative combining function
3948	>	* @return the result of accumulating the given transformation
3949	>	* of all keys
3950	>	* @since 1.8
3951		*/
3952	<	public V remove(Object key) {
3953	<	int hash = hash(key);
3954	<	return segmentFor(hash).remove(key, hash, null);
3952	>	public double reduceKeysToDouble(long parallelismThreshold,
3953	>	ToDoubleFunction<? super K> transformer,
3954	>	double basis,
3955	>	DoubleBinaryOperator reducer) {
3956	>	if (transformer == null || reducer == null)
3957	>	throw new NullPointerException();
3958	>	return new MapReduceKeysToDoubleTask<K,V>
3959	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3960	>	null, transformer, basis, reducer).invoke();
3961		}
3962
3963		/**
3964	<	* Remove entry for key only if currently mapped to given value.
3965	<	* Acts as
3966	<	* <pre>
3967	<	*  if (map.get(key).equals(value)) {
3968	<	*     map.remove(key);
3969	<	*     return true;
3970	<	* } else return false;
3971	<	* </pre>
3972	<	* except that the action is performed atomically.
3973	<	* @param key key with which the specified value is associated.
3974	<	* @param value value associated with the specified key.
3975	<	* @return true if the value was removed
3976	<	* @throws NullPointerException if the specified key is
847	<	*            <tt>null</tt>.
3964	>	* Returns the result of accumulating the given transformation
3965	>	* of all keys using the given reducer to combine values, and
3966	>	* the given basis as an identity value.
3967	>	*
3968	>	* @param parallelismThreshold the (estimated) number of elements
3969	>	* needed for this operation to be executed in parallel
3970	>	* @param transformer a function returning the transformation
3971	>	* for an element
3972	>	* @param basis the identity (initial default value) for the reduction
3973	>	* @param reducer a commutative associative combining function
3974	>	* @return the result of accumulating the given transformation
3975	>	* of all keys
3976	>	* @since 1.8
3977		*/
3978	<	public boolean remove(Object key, Object value) {
3979	<	int hash = hash(key);
3980	<	return segmentFor(hash).remove(key, hash, value) != null;
3978	>	public long reduceKeysToLong(long parallelismThreshold,
3979	>	ToLongFunction<? super K> transformer,
3980	>	long basis,
3981	>	LongBinaryOperator reducer) {
3982	>	if (transformer == null || reducer == null)
3983	>	throw new NullPointerException();
3984	>	return new MapReduceKeysToLongTask<K,V>
3985	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3986	>	null, transformer, basis, reducer).invoke();
3987		}
3988
3989	+	/**
3990	+	* Returns the result of accumulating the given transformation
3991	+	* of all keys using the given reducer to combine values, and
3992	+	* the given basis as an identity value.
3993	+	*
3994	+	* @param parallelismThreshold the (estimated) number of elements
3995	+	* needed for this operation to be executed in parallel
3996	+	* @param transformer a function returning the transformation
3997	+	* for an element
3998	+	* @param basis the identity (initial default value) for the reduction
3999	+	* @param reducer a commutative associative combining function
4000	+	* @return the result of accumulating the given transformation
4001	+	* of all keys
4002	+	* @since 1.8
4003	+	*/
4004	+	public int reduceKeysToInt(long parallelismThreshold,
4005	+	ToIntFunction<? super K> transformer,
4006	+	int basis,
4007	+	IntBinaryOperator reducer) {
4008	+	if (transformer == null || reducer == null)
4009	+	throw new NullPointerException();
4010	+	return new MapReduceKeysToIntTask<K,V>
4011	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4012	+	null, transformer, basis, reducer).invoke();
4013	+	}
4014
4015		/**
4016	<	* Replace entry for key only if currently mapped to given value.
4017	<	* Acts as
4018	<	* <pre>
4019	<	*  if (map.get(key).equals(oldValue)) {
4020	<	*     map.put(key, newValue);
4021	<	*     return true;
862	<	* } else return false;
863	<	* </pre>
864	<	* except that the action is performed atomically.
865	<	* @param key key with which the specified value is associated.
866	<	* @param oldValue value expected to be associated with the specified key.
867	<	* @param newValue value to be associated with the specified key.
868	<	* @return true if the value was replaced
869	<	* @throws NullPointerException if the specified key or values are
870	<	* <tt>null</tt>.
4016	>	* Performs the given action for each value.
4017	>	*
4018	>	* @param parallelismThreshold the (estimated) number of elements
4019	>	* needed for this operation to be executed in parallel
4020	>	* @param action the action
4021	>	* @since 1.8
4022		*/
4023	<	public boolean replace(K key, V oldValue, V newValue) {
4024	<	if (oldValue == null || newValue == null)
4023	>	public void forEachValue(long parallelismThreshold,
4024	>	Consumer<? super V> action) {
4025	>	if (action == null)
4026		throw new NullPointerException();
4027	<	int hash = hash(key);
4028	<	return segmentFor(hash).replace(key, hash, oldValue, newValue);
4027	>	new ForEachValueTask<K,V>
4028	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4029	>	action).invoke();
4030		}
4031
4032		/**
4033	<	* Replace entry for key only if currently mapped to some value.
4034	<	* Acts as
4035	<	* <pre>
4036	<	*  if ((map.containsKey(key)) {
4037	<	*     return map.put(key, value);
4038	<	* } else return null;
4039	<	* </pre>
4040	<	* except that the action is performed atomically.
4041	<	* @param key key with which the specified value is associated.
4042	<	* @param value value to be associated with the specified key.
4043	<	* @return previous value associated with specified key, or <tt>null</tt>
891	<	*         if there was no mapping for key.
892	<	* @throws NullPointerException if the specified key or value is
893	<	*            <tt>null</tt>.
4033	>	* Performs the given action for each non-null transformation
4034	>	* of each value.
4035	>	*
4036	>	* @param parallelismThreshold the (estimated) number of elements
4037	>	* needed for this operation to be executed in parallel
4038	>	* @param transformer a function returning the transformation
4039	>	* for an element, or null if there is no transformation (in
4040	>	* which case the action is not applied)
4041	>	* @param action the action
4042	>	* @param <U> the return type of the transformer
4043	>	* @since 1.8
4044		*/
4045	<	public V replace(K key, V value) {
4046	<	if (value == null)
4045	>	public <U> void forEachValue(long parallelismThreshold,
4046	>	Function<? super V, ? extends U> transformer,
4047	>	Consumer<? super U> action) {
4048	>	if (transformer == null || action == null)
4049		throw new NullPointerException();
4050	<	int hash = hash(key);
4051	<	return segmentFor(hash).replace(key, hash, value);
4050	>	new ForEachTransformedValueTask<K,V,U>
4051	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4052	>	transformer, action).invoke();
4053		}
4054
4055	+	/**
4056	+	* Returns a non-null result from applying the given search
4057	+	* function on each value, or null if none.  Upon success,
4058	+	* further element processing is suppressed and the results of
4059	+	* any other parallel invocations of the search function are
4060	+	* ignored.
4061	+	*
4062	+	* @param parallelismThreshold the (estimated) number of elements
4063	+	* needed for this operation to be executed in parallel
4064	+	* @param searchFunction a function returning a non-null
4065	+	* result on success, else null
4066	+	* @param <U> the return type of the search function
4067	+	* @return a non-null result from applying the given search
4068	+	* function on each value, or null if none
4069	+	* @since 1.8
4070	+	*/
4071	+	public <U> U searchValues(long parallelismThreshold,
4072	+	Function<? super V, ? extends U> searchFunction) {
4073	+	if (searchFunction == null) throw new NullPointerException();
4074	+	return new SearchValuesTask<K,V,U>
4075	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4076	+	searchFunction, new AtomicReference<U>()).invoke();
4077	+	}
4078
4079		/**
4080	<	* Removes all mappings from this map.
4080	>	* Returns the result of accumulating all values using the
4081	>	* given reducer to combine values, or null if none.
4082	>	*
4083	>	* @param parallelismThreshold the (estimated) number of elements
4084	>	* needed for this operation to be executed in parallel
4085	>	* @param reducer a commutative associative combining function
4086	>	* @return the result of accumulating all values
4087	>	* @since 1.8
4088		*/
4089	<	public void clear() {
4090	<	for (int i = 0; i < segments.length; ++i)
4091	<	segments[i].clear();
4089	>	public V reduceValues(long parallelismThreshold,
4090	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4091	>	if (reducer == null) throw new NullPointerException();
4092	>	return new ReduceValuesTask<K,V>
4093	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4094	>	null, reducer).invoke();
4095		}
4096
4097	+	/**
4098	+	* Returns the result of accumulating the given transformation
4099	+	* of all values using the given reducer to combine values, or
4100	+	* null if none.
4101	+	*
4102	+	* @param parallelismThreshold the (estimated) number of elements
4103	+	* needed for this operation to be executed in parallel
4104	+	* @param transformer a function returning the transformation
4105	+	* for an element, or null if there is no transformation (in
4106	+	* which case it is not combined)
4107	+	* @param reducer a commutative associative combining function
4108	+	* @param <U> the return type of the transformer
4109	+	* @return the result of accumulating the given transformation
4110	+	* of all values
4111	+	* @since 1.8
4112	+	*/
4113	+	public <U> U reduceValues(long parallelismThreshold,
4114	+	Function<? super V, ? extends U> transformer,
4115	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4116	+	if (transformer == null || reducer == null)
4117	+	throw new NullPointerException();
4118	+	return new MapReduceValuesTask<K,V,U>
4119	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4120	+	null, transformer, reducer).invoke();
4121	+	}
4122
4123		/**
4124	<	* Returns a shallow copy of this
4125	<	* <tt>ConcurrentHashMap</tt> instance: the keys and
4126	<	* values themselves are not cloned.
4124	>	* Returns the result of accumulating the given transformation
4125	>	* of all values using the given reducer to combine values,
4126	>	* and the given basis as an identity value.
4127		*
4128	<	* @return a shallow copy of this map.
4128	>	* @param parallelismThreshold the (estimated) number of elements
4129	>	* needed for this operation to be executed in parallel
4130	>	* @param transformer a function returning the transformation
4131	>	* for an element
4132	>	* @param basis the identity (initial default value) for the reduction
4133	>	* @param reducer a commutative associative combining function
4134	>	* @return the result of accumulating the given transformation
4135	>	* of all values
4136	>	* @since 1.8
4137		*/
4138	<	public Object clone() {
4139	<	// We cannot call super.clone, since it would share final
4140	<	// segments array, and there's no way to reassign finals.
4138	>	public double reduceValuesToDouble(long parallelismThreshold,
4139	>	ToDoubleFunction<? super V> transformer,
4140	>	double basis,
4141	>	DoubleBinaryOperator reducer) {
4142	>	if (transformer == null || reducer == null)
4143	>	throw new NullPointerException();
4144	>	return new MapReduceValuesToDoubleTask<K,V>
4145	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4146	>	null, transformer, basis, reducer).invoke();
4147	>	}
4148
4149	<	float lf = segments[0].loadFactor;
4150	<	int segs = segments.length;
4151	<	int cap = (int)(size() / lf);
4152	<	if (cap < segs) cap = segs;
4153	<	ConcurrentHashMap<K,V> t = new ConcurrentHashMap<K,V>(cap, lf, segs);
4154	<	t.putAll(this);
4155	<	return t;
4149	>	/**
4150	>	* Returns the result of accumulating the given transformation
4151	>	* of all values using the given reducer to combine values,
4152	>	* and the given basis as an identity value.
4153	>	*
4154	>	* @param parallelismThreshold the (estimated) number of elements
4155	>	* needed for this operation to be executed in parallel
4156	>	* @param transformer a function returning the transformation
4157	>	* for an element
4158	>	* @param basis the identity (initial default value) for the reduction
4159	>	* @param reducer a commutative associative combining function
4160	>	* @return the result of accumulating the given transformation
4161	>	* of all values
4162	>	* @since 1.8
4163	>	*/
4164	>	public long reduceValuesToLong(long parallelismThreshold,
4165	>	ToLongFunction<? super V> transformer,
4166	>	long basis,
4167	>	LongBinaryOperator reducer) {
4168	>	if (transformer == null || reducer == null)
4169	>	throw new NullPointerException();
4170	>	return new MapReduceValuesToLongTask<K,V>
4171	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4172	>	null, transformer, basis, reducer).invoke();
4173		}
4174
4175		/**
4176	<	* Returns a set view of the keys contained in this map.  The set is
4177	<	* backed by the map, so changes to the map are reflected in the set, and
4178	<	* vice-versa.  The set supports element removal, which removes the
936	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
937	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
938	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
939	<	* <tt>addAll</tt> operations.
940	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
941	<	* will never throw {@link java.util.ConcurrentModificationException},
942	<	* and guarantees to traverse elements as they existed upon
943	<	* construction of the iterator, and may (but is not guaranteed to)
944	<	* reflect any modifications subsequent to construction.
4176	>	* Returns the result of accumulating the given transformation
4177	>	* of all values using the given reducer to combine values,
4178	>	* and the given basis as an identity value.
4179		*
4180	<	* @return a set view of the keys contained in this map.
4180	>	* @param parallelismThreshold the (estimated) number of elements
4181	>	* needed for this operation to be executed in parallel
4182	>	* @param transformer a function returning the transformation
4183	>	* for an element
4184	>	* @param basis the identity (initial default value) for the reduction
4185	>	* @param reducer a commutative associative combining function
4186	>	* @return the result of accumulating the given transformation
4187	>	* of all values
4188	>	* @since 1.8
4189		*/
4190	<	public Set<K> keySet() {
4191	<	Set<K> ks = keySet;
4192	<	return (ks != null) ? ks : (keySet = new KeySet());
4190	>	public int reduceValuesToInt(long parallelismThreshold,
4191	>	ToIntFunction<? super V> transformer,
4192	>	int basis,
4193	>	IntBinaryOperator reducer) {
4194	>	if (transformer == null || reducer == null)
4195	>	throw new NullPointerException();
4196	>	return new MapReduceValuesToIntTask<K,V>
4197	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4198	>	null, transformer, basis, reducer).invoke();
4199		}
4200
4201	+	/**
4202	+	* Performs the given action for each entry.
4203	+	*
4204	+	* @param parallelismThreshold the (estimated) number of elements
4205	+	* needed for this operation to be executed in parallel
4206	+	* @param action the action
4207	+	* @since 1.8
4208	+	*/
4209	+	public void forEachEntry(long parallelismThreshold,
4210	+	Consumer<? super Map.Entry<K,V>> action) {
4211	+	if (action == null) throw new NullPointerException();
4212	+	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4213	+	action).invoke();
4214	+	}
4215
4216		/**
4217	<	* Returns a collection view of the values contained in this map.  The
4218	<	* collection is backed by the map, so changes to the map are reflected in
957	<	* the collection, and vice-versa.  The collection supports element
958	<	* removal, which removes the corresponding mapping from this map, via the
959	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
960	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
961	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
962	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
963	<	* will never throw {@link java.util.ConcurrentModificationException},
964	<	* and guarantees to traverse elements as they existed upon
965	<	* construction of the iterator, and may (but is not guaranteed to)
966	<	* reflect any modifications subsequent to construction.
4217	>	* Performs the given action for each non-null transformation
4218	>	* of each entry.
4219		*
4220	<	* @return a collection view of the values contained in this map.
4220	>	* @param parallelismThreshold the (estimated) number of elements
4221	>	* needed for this operation to be executed in parallel
4222	>	* @param transformer a function returning the transformation
4223	>	* for an element, or null if there is no transformation (in
4224	>	* which case the action is not applied)
4225	>	* @param action the action
4226	>	* @param <U> the return type of the transformer
4227	>	* @since 1.8
4228		*/
4229	<	public Collection<V> values() {
4230	<	Collection<V> vs = values;
4231	<	return (vs != null) ? vs : (values = new Values());
4229	>	public <U> void forEachEntry(long parallelismThreshold,
4230	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4231	>	Consumer<? super U> action) {
4232	>	if (transformer == null || action == null)
4233	>	throw new NullPointerException();
4234	>	new ForEachTransformedEntryTask<K,V,U>
4235	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4236	>	transformer, action).invoke();
4237		}
4238
4239	+	/**
4240	+	* Returns a non-null result from applying the given search
4241	+	* function on each entry, or null if none.  Upon success,
4242	+	* further element processing is suppressed and the results of
4243	+	* any other parallel invocations of the search function are
4244	+	* ignored.
4245	+	*
4246	+	* @param parallelismThreshold the (estimated) number of elements
4247	+	* needed for this operation to be executed in parallel
4248	+	* @param searchFunction a function returning a non-null
4249	+	* result on success, else null
4250	+	* @param <U> the return type of the search function
4251	+	* @return a non-null result from applying the given search
4252	+	* function on each entry, or null if none
4253	+	* @since 1.8
4254	+	*/
4255	+	public <U> U searchEntries(long parallelismThreshold,
4256	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4257	+	if (searchFunction == null) throw new NullPointerException();
4258	+	return new SearchEntriesTask<K,V,U>
4259	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4260	+	searchFunction, new AtomicReference<U>()).invoke();
4261	+	}
4262
4263		/**
4264	<	* Returns a collection view of the mappings contained in this map.  Each
4265	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
979	<	* collection is backed by the map, so changes to the map are reflected in
980	<	* the collection, and vice-versa.  The collection supports element
981	<	* removal, which removes the corresponding mapping from the map, via the
982	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
983	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
984	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
985	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
986	<	* will never throw {@link java.util.ConcurrentModificationException},
987	<	* and guarantees to traverse elements as they existed upon
988	<	* construction of the iterator, and may (but is not guaranteed to)
989	<	* reflect any modifications subsequent to construction.
4264	>	* Returns the result of accumulating all entries using the
4265	>	* given reducer to combine values, or null if none.
4266		*
4267	<	* @return a collection view of the mappings contained in this map.
4267	>	* @param parallelismThreshold the (estimated) number of elements
4268	>	* needed for this operation to be executed in parallel
4269	>	* @param reducer a commutative associative combining function
4270	>	* @return the result of accumulating all entries
4271	>	* @since 1.8
4272		*/
4273	<	public Set<Map.Entry<K,V>> entrySet() {
4274	<	Set<Map.Entry<K,V>> es = entrySet;
4275	<	return (es != null) ? es : (entrySet = (Set<Map.Entry<K,V>>) (Set) new EntrySet());
4273	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4274	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4275	>	if (reducer == null) throw new NullPointerException();
4276	>	return new ReduceEntriesTask<K,V>
4277	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4278	>	null, reducer).invoke();
4279		}
4280
4281	+	/**
4282	+	* Returns the result of accumulating the given transformation
4283	+	* of all entries using the given reducer to combine values,
4284	+	* or null if none.
4285	+	*
4286	+	* @param parallelismThreshold the (estimated) number of elements
4287	+	* needed for this operation to be executed in parallel
4288	+	* @param transformer a function returning the transformation
4289	+	* for an element, or null if there is no transformation (in
4290	+	* which case it is not combined)
4291	+	* @param reducer a commutative associative combining function
4292	+	* @param <U> the return type of the transformer
4293	+	* @return the result of accumulating the given transformation
4294	+	* of all entries
4295	+	* @since 1.8
4296	+	*/
4297	+	public <U> U reduceEntries(long parallelismThreshold,
4298	+	Function<Map.Entry<K,V>, ? extends U> transformer,
4299	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4300	+	if (transformer == null || reducer == null)
4301	+	throw new NullPointerException();
4302	+	return new MapReduceEntriesTask<K,V,U>
4303	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4304	+	null, transformer, reducer).invoke();
4305	+	}
4306
4307		/**
4308	<	* Returns an enumeration of the keys in this table.
4308	>	* Returns the result of accumulating the given transformation
4309	>	* of all entries using the given reducer to combine values,
4310	>	* and the given basis as an identity value.
4311		*
4312	<	* @return  an enumeration of the keys in this table.
4313	<	* @see     #keySet
4312	>	* @param parallelismThreshold the (estimated) number of elements
4313	>	* needed for this operation to be executed in parallel
4314	>	* @param transformer a function returning the transformation
4315	>	* for an element
4316	>	* @param basis the identity (initial default value) for the reduction
4317	>	* @param reducer a commutative associative combining function
4318	>	* @return the result of accumulating the given transformation
4319	>	* of all entries
4320	>	* @since 1.8
4321		*/
4322	<	public Enumeration<K> keys() {
4323	<	return new KeyIterator();
4322	>	public double reduceEntriesToDouble(long parallelismThreshold,
4323	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4324	>	double basis,
4325	>	DoubleBinaryOperator reducer) {
4326	>	if (transformer == null || reducer == null)
4327	>	throw new NullPointerException();
4328	>	return new MapReduceEntriesToDoubleTask<K,V>
4329	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4330	>	null, transformer, basis, reducer).invoke();
4331		}
4332
4333		/**
4334	<	* Returns an enumeration of the values in this table.
4335	<	* Use the Enumeration methods on the returned object to fetch the elements
4336	<	* sequentially.
4334	>	* Returns the result of accumulating the given transformation
4335	>	* of all entries using the given reducer to combine values,
4336	>	* and the given basis as an identity value.
4337		*
4338	<	* @return  an enumeration of the values in this table.
4339	<	* @see     #values
4338	>	* @param parallelismThreshold the (estimated) number of elements
4339	>	* needed for this operation to be executed in parallel
4340	>	* @param transformer a function returning the transformation
4341	>	* for an element
4342	>	* @param basis the identity (initial default value) for the reduction
4343	>	* @param reducer a commutative associative combining function
4344	>	* @return the result of accumulating the given transformation
4345	>	* of all entries
4346	>	* @since 1.8
4347		*/
4348	<	public Enumeration<V> elements() {
4349	<	return new ValueIterator();
4348	>	public long reduceEntriesToLong(long parallelismThreshold,
4349	>	ToLongFunction<Map.Entry<K,V>> transformer,
4350	>	long basis,
4351	>	LongBinaryOperator reducer) {
4352	>	if (transformer == null || reducer == null)
4353	>	throw new NullPointerException();
4354	>	return new MapReduceEntriesToLongTask<K,V>
4355	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4356	>	null, transformer, basis, reducer).invoke();
4357		}
4358
4359	<	/* ---------------- Iterator Support -------------- */
4359	>	/**
4360	>	* Returns the result of accumulating the given transformation
4361	>	* of all entries using the given reducer to combine values,
4362	>	* and the given basis as an identity value.
4363	>	*
4364	>	* @param parallelismThreshold the (estimated) number of elements
4365	>	* needed for this operation to be executed in parallel
4366	>	* @param transformer a function returning the transformation
4367	>	* for an element
4368	>	* @param basis the identity (initial default value) for the reduction
4369	>	* @param reducer a commutative associative combining function
4370	>	* @return the result of accumulating the given transformation
4371	>	* of all entries
4372	>	* @since 1.8
4373	>	*/
4374	>	public int reduceEntriesToInt(long parallelismThreshold,
4375	>	ToIntFunction<Map.Entry<K,V>> transformer,
4376	>	int basis,
4377	>	IntBinaryOperator reducer) {
4378	>	if (transformer == null || reducer == null)
4379	>	throw new NullPointerException();
4380	>	return new MapReduceEntriesToIntTask<K,V>
4381	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4382	>	null, transformer, basis, reducer).invoke();
4383	>	}
4384
1023	–	private abstract class HashIterator {
1024	–	private int nextSegmentIndex;
1025	–	private int nextTableIndex;
1026	–	private HashEntry[] currentTable;
1027	–	private HashEntry<K, V> nextEntry;
1028	–	HashEntry<K, V> lastReturned;
4385
4386	<	private HashIterator() {
1031	<	nextSegmentIndex = segments.length - 1;
1032	<	nextTableIndex = -1;
1033	<	advance();
1034	<	}
4386	>	/* ----------------Views -------------- */
4387
4388	<	public boolean hasMoreElements() { return hasNext(); }
4388	>	/**
4389	>	* Base class for views.
4390	>	*/
4391	>	abstract static class CollectionView<K,V,E>
4392	>	implements Collection<E>, java.io.Serializable {
4393	>	private static final long serialVersionUID = 7249069246763182397L;
4394	>	final ConcurrentHashMap<K,V> map;
4395	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4396
4397	<	private void advance() {
4398	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
4399	<	return;
4397	>	/**
4398	>	* Returns the map backing this view.
4399	>	*
4400	>	* @return the map backing this view
4401	>	*/
4402	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4403
4404	<	while (nextTableIndex >= 0) {
4405	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[nextTableIndex--]) != null)
4406	<	return;
4404	>	/**
4405	>	* Removes all of the elements from this view, by removing all
4406	>	* the mappings from the map backing this view.
4407	>	*/
4408	>	public final void clear()      { map.clear(); }
4409	>	public final int size()        { return map.size(); }
4410	>	public final boolean isEmpty() { return map.isEmpty(); }
4411	>
4412	>	// implementations below rely on concrete classes supplying these
4413	>	// abstract methods
4414	>	/**
4415	>	* Returns an iterator over the elements in this collection.
4416	>	*
4417	>	* <p>The returned iterator is
4418	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4419	>	*
4420	>	* @return an iterator over the elements in this collection
4421	>	*/
4422	>	public abstract Iterator<E> iterator();
4423	>	public abstract boolean contains(Object o);
4424	>	public abstract boolean remove(Object o);
4425	>
4426	>	private static final String oomeMsg = "Required array size too large";
4427	>
4428	>	public final Object[] toArray() {
4429	>	long sz = map.mappingCount();
4430	>	if (sz > MAX_ARRAY_SIZE)
4431	>	throw new OutOfMemoryError(oomeMsg);
4432	>	int n = (int)sz;
4433	>	Object[] r = new Object[n];
4434	>	int i = 0;
4435	>	for (E e : this) {
4436	>	if (i == n) {
4437	>	if (n >= MAX_ARRAY_SIZE)
4438	>	throw new OutOfMemoryError(oomeMsg);
4439	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4440	>	n = MAX_ARRAY_SIZE;
4441	>	else
4442	>	n += (n >>> 1) + 1;
4443	>	r = Arrays.copyOf(r, n);
4444	>	}
4445	>	r[i++] = e;
4446		}
4447	+	return (i == n) ? r : Arrays.copyOf(r, i);
4448	+	}
4449
4450	<	while (nextSegmentIndex >= 0) {
4451	<	Segment<K,V> seg = (Segment<K,V>)segments[nextSegmentIndex--];
4452	<	if (seg.count != 0) {
4453	<	currentTable = seg.table;
4454	<	for (int j = currentTable.length - 1; j >= 0; --j) {
4455	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[j]) != null) {
4456	<	nextTableIndex = j - 1;
4457	<	return;
4458	<	}
4459	<	}
4450	>	@SuppressWarnings("unchecked")
4451	>	public final <T> T[] toArray(T[] a) {
4452	>	long sz = map.mappingCount();
4453	>	if (sz > MAX_ARRAY_SIZE)
4454	>	throw new OutOfMemoryError(oomeMsg);
4455	>	int m = (int)sz;
4456	>	T[] r = (a.length >= m) ? a :
4457	>	(T[])java.lang.reflect.Array
4458	>	.newInstance(a.getClass().getComponentType(), m);
4459	>	int n = r.length;
4460	>	int i = 0;
4461	>	for (E e : this) {
4462	>	if (i == n) {
4463	>	if (n >= MAX_ARRAY_SIZE)
4464	>	throw new OutOfMemoryError(oomeMsg);
4465	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4466	>	n = MAX_ARRAY_SIZE;
4467	>	else
4468	>	n += (n >>> 1) + 1;
4469	>	r = Arrays.copyOf(r, n);
4470		}
4471	+	r[i++] = (T)e;
4472	+	}
4473	+	if (a == r && i < n) {
4474	+	r[i] = null; // null-terminate
4475	+	return r;
4476		}
4477	+	return (i == n) ? r : Arrays.copyOf(r, i);
4478		}
4479
4480	<	public boolean hasNext() { return nextEntry != null; }
4480	>	/**
4481	>	* Returns a string representation of this collection.
4482	>	* The string representation consists of the string representations
4483	>	* of the collection's elements in the order they are returned by
4484	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4485	>	* Adjacent elements are separated by the characters {@code ", "}
4486	>	* (comma and space).  Elements are converted to strings as by
4487	>	* {@link String#valueOf(Object)}.
4488	>	*
4489	>	* @return a string representation of this collection
4490	>	*/
4491	>	public final String toString() {
4492	>	StringBuilder sb = new StringBuilder();
4493	>	sb.append('[');
4494	>	Iterator<E> it = iterator();
4495	>	if (it.hasNext()) {
4496	>	for (;;) {
4497	>	Object e = it.next();
4498	>	sb.append(e == this ? "(this Collection)" : e);
4499	>	if (!it.hasNext())
4500	>	break;
4501	>	sb.append(',').append(' ');
4502	>	}
4503	>	}
4504	>	return sb.append(']').toString();
4505	>	}
4506
4507	<	HashEntry<K,V> nextEntry() {
4508	<	if (nextEntry == null)
4509	<	throw new NoSuchElementException();
4510	<	lastReturned = nextEntry;
4511	<	advance();
4512	<	return lastReturned;
4507	>	public final boolean containsAll(Collection<?> c) {
4508	>	if (c != this) {
4509	>	for (Object e : c) {
4510	>	if (e == null || !contains(e))
4511	>	return false;
4512	>	}
4513	>	}
4514	>	return true;
4515		}
4516
4517	<	public void remove() {
4518	<	if (lastReturned == null)
4519	<	throw new IllegalStateException();
4520	<	ConcurrentHashMap.this.remove(lastReturned.key);
4521	<	lastReturned = null;
4517	>	public final boolean removeAll(Collection<?> c) {
4518	>	if (c == null) throw new NullPointerException();
4519	>	boolean modified = false;
4520	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4521	>	if (c.contains(it.next())) {
4522	>	it.remove();
4523	>	modified = true;
4524	>	}
4525	>	}
4526	>	return modified;
4527		}
1077	–	}
4528
4529	<	private class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
4530	<	public K next() { return super.nextEntry().key; }
4531	<	public K nextElement() { return super.nextEntry().key; }
4532	<	}
4529	>	public final boolean retainAll(Collection<?> c) {
4530	>	if (c == null) throw new NullPointerException();
4531	>	boolean modified = false;
4532	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4533	>	if (!c.contains(it.next())) {
4534	>	it.remove();
4535	>	modified = true;
4536	>	}
4537	>	}
4538	>	return modified;
4539	>	}
4540
1084	–	private class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
1085	–	public V next() { return super.nextEntry().value; }
1086	–	public V nextElement() { return super.nextEntry().value; }
4541		}
4542
1089	–
1090	–
4543		/**
4544	<	* Exported Entry objects must write-through changes in setValue,
4545	<	* even if the nodes have been cloned. So we cannot return
4546	<	* internal HashEntry objects. Instead, the iterator itself acts
4547	<	* as a forwarding pseudo-entry.
4544	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4545	>	* which additions may optionally be enabled by mapping to a
4546	>	* common value.  This class cannot be directly instantiated.
4547	>	* See {@link #keySet() keySet()},
4548	>	* {@link #keySet(Object) keySet(V)},
4549	>	* {@link #newKeySet() newKeySet()},
4550	>	* {@link #newKeySet(int) newKeySet(int)}.
4551	>	*
4552	>	* @since 1.8
4553		*/
4554	<	private class EntryIterator extends HashIterator implements Map.Entry<K,V>, Iterator<Entry<K,V>> {
4555	<	public Map.Entry<K,V> next() {
4556	<	nextEntry();
4557	<	return this;
4554	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4555	>	implements Set<K>, java.io.Serializable {
4556	>	private static final long serialVersionUID = 7249069246763182397L;
4557	>	private final V value;
4558	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4559	>	super(map);
4560	>	this.value = value;
4561	>	}
4562	>
4563	>	/**
4564	>	* Returns the default mapped value for additions,
4565	>	* or {@code null} if additions are not supported.
4566	>	*
4567	>	* @return the default mapped value for additions, or {@code null}
4568	>	* if not supported
4569	>	*/
4570	>	public V getMappedValue() { return value; }
4571	>
4572	>	/**
4573	>	* {@inheritDoc}
4574	>	* @throws NullPointerException if the specified key is null
4575	>	*/
4576	>	public boolean contains(Object o) { return map.containsKey(o); }
4577	>
4578	>	/**
4579	>	* Removes the key from this map view, by removing the key (and its
4580	>	* corresponding value) from the backing map.  This method does
4581	>	* nothing if the key is not in the map.
4582	>	*
4583	>	* @param  o the key to be removed from the backing map
4584	>	* @return {@code true} if the backing map contained the specified key
4585	>	* @throws NullPointerException if the specified key is null
4586	>	*/
4587	>	public boolean remove(Object o) { return map.remove(o) != null; }
4588	>
4589	>	/**
4590	>	* @return an iterator over the keys of the backing map
4591	>	*/
4592	>	public Iterator<K> iterator() {
4593	>	Node<K,V>[] t;
4594	>	ConcurrentHashMap<K,V> m = map;
4595	>	int f = (t = m.table) == null ? 0 : t.length;
4596	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4597		}
4598
4599	<	public K getKey() {
4600	<	if (lastReturned == null)
4601	<	throw new IllegalStateException("Entry was removed");
4602	<	return lastReturned.key;
4599	>	/**
4600	>	* Adds the specified key to this set view by mapping the key to
4601	>	* the default mapped value in the backing map, if defined.
4602	>	*
4603	>	* @param e key to be added
4604	>	* @return {@code true} if this set changed as a result of the call
4605	>	* @throws NullPointerException if the specified key is null
4606	>	* @throws UnsupportedOperationException if no default mapped value
4607	>	* for additions was provided
4608	>	*/
4609	>	public boolean add(K e) {
4610	>	V v;
4611	>	if ((v = value) == null)
4612	>	throw new UnsupportedOperationException();
4613	>	return map.putVal(e, v, true) == null;
4614		}
4615
4616	<	public V getValue() {
4617	<	if (lastReturned == null)
4618	<	throw new IllegalStateException("Entry was removed");
4619	<	return ConcurrentHashMap.this.get(lastReturned.key);
4616	>	/**
4617	>	* Adds all of the elements in the specified collection to this set,
4618	>	* as if by calling {@link #add} on each one.
4619	>	*
4620	>	* @param c the elements to be inserted into this set
4621	>	* @return {@code true} if this set changed as a result of the call
4622	>	* @throws NullPointerException if the collection or any of its
4623	>	* elements are {@code null}
4624	>	* @throws UnsupportedOperationException if no default mapped value
4625	>	* for additions was provided
4626	>	*/
4627	>	public boolean addAll(Collection<? extends K> c) {
4628	>	boolean added = false;
4629	>	V v;
4630	>	if ((v = value) == null)
4631	>	throw new UnsupportedOperationException();
4632	>	for (K e : c) {
4633	>	if (map.putVal(e, v, true) == null)
4634	>	added = true;
4635	>	}
4636	>	return added;
4637		}
4638
4639	<	public V setValue(V value) {
4640	<	if (lastReturned == null)
4641	<	throw new IllegalStateException("Entry was removed");
4642	<	return ConcurrentHashMap.this.put(lastReturned.key, value);
4639	>	public int hashCode() {
4640	>	int h = 0;
4641	>	for (K e : this)
4642	>	h += e.hashCode();
4643	>	return h;
4644		}
4645
4646		public boolean equals(Object o) {
4647	<	if (!(o instanceof Map.Entry))
4648	<	return false;
4649	<	Map.Entry e = (Map.Entry)o;
4650	<	return eq(getKey(), e.getKey()) && eq(getValue(), e.getValue());
4651	<	}
4647	>	Set<?> c;
4648	>	return ((o instanceof Set) &&
4649	>	((c = (Set<?>)o) == this ||
4650	>	(containsAll(c) && c.containsAll(this))));
4651	>	}
4652	>
4653	>	public Spliterator<K> spliterator() {
4654	>	Node<K,V>[] t;
4655	>	ConcurrentHashMap<K,V> m = map;
4656	>	long n = m.sumCount();
4657	>	int f = (t = m.table) == null ? 0 : t.length;
4658	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4659	>	}
4660	>
4661	>	public void forEach(Consumer<? super K> action) {
4662	>	if (action == null) throw new NullPointerException();
4663	>	Node<K,V>[] t;
4664	>	if ((t = map.table) != null) {
4665	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4666	>	for (Node<K,V> p; (p = it.advance()) != null; )
4667	>	action.accept(p.key);
4668	>	}
4669	>	}
4670	>	}
4671
4672	<	public int hashCode() {
4673	<	Object k = getKey();
4674	<	Object v = getValue();
4675	<	return ((k == null) ? 0 : k.hashCode()) ^
4676	<	((v == null) ? 0 : v.hashCode());
4672	>	/**
4673	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4674	>	* values, in which additions are disabled. This class cannot be
4675	>	* directly instantiated. See {@link #values()}.
4676	>	*/
4677	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4678	>	implements Collection<V>, java.io.Serializable {
4679	>	private static final long serialVersionUID = 2249069246763182397L;
4680	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4681	>	public final boolean contains(Object o) {
4682	>	return map.containsValue(o);
4683		}
4684
4685	<	public String toString() {
4686	<	return getKey() + "=" + getValue();
4685	>	public final boolean remove(Object o) {
4686	>	if (o != null) {
4687	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4688	>	if (o.equals(it.next())) {
4689	>	it.remove();
4690	>	return true;
4691	>	}
4692	>	}
4693	>	}
4694	>	return false;
4695		}
4696
4697	<	private boolean eq(Object o1, Object o2) {
4698	<	return (o1 == null ? o2 == null : o1.equals(o2));
4697	>	public final Iterator<V> iterator() {
4698	>	ConcurrentHashMap<K,V> m = map;
4699	>	Node<K,V>[] t;
4700	>	int f = (t = m.table) == null ? 0 : t.length;
4701	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4702		}
4703
4704	<	}
4704	>	public final boolean add(V e) {
4705	>	throw new UnsupportedOperationException();
4706	>	}
4707	>	public final boolean addAll(Collection<? extends V> c) {
4708	>	throw new UnsupportedOperationException();
4709	>	}
4710
4711	<	private class KeySet extends AbstractSet<K> {
4712	<	public Iterator<K> iterator() {
4713	<	return new KeyIterator();
4711	>	public boolean removeIf(Predicate<? super V> filter) {
4712	>	return map.removeValueIf(filter);
4713	>	}
4714	>
4715	>	public Spliterator<V> spliterator() {
4716	>	Node<K,V>[] t;
4717	>	ConcurrentHashMap<K,V> m = map;
4718	>	long n = m.sumCount();
4719	>	int f = (t = m.table) == null ? 0 : t.length;
4720	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4721		}
4722	<	public int size() {
4723	<	return ConcurrentHashMap.this.size();
4722	>
4723	>	public void forEach(Consumer<? super V> action) {
4724	>	if (action == null) throw new NullPointerException();
4725	>	Node<K,V>[] t;
4726	>	if ((t = map.table) != null) {
4727	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4728	>	for (Node<K,V> p; (p = it.advance()) != null; )
4729	>	action.accept(p.val);
4730	>	}
4731		}
4732	+	}
4733	+
4734	+	/**
4735	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4736	+	* entries.  This class cannot be directly instantiated. See
4737	+	* {@link #entrySet()}.
4738	+	*/
4739	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4740	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4741	+	private static final long serialVersionUID = 2249069246763182397L;
4742	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4743	+
4744		public boolean contains(Object o) {
4745	<	return ConcurrentHashMap.this.containsKey(o);
4745	>	Object k, v, r; Map.Entry<?,?> e;
4746	>	return ((o instanceof Map.Entry) &&
4747	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4748	>	(r = map.get(k)) != null &&
4749	>	(v = e.getValue()) != null &&
4750	>	(v == r || v.equals(r)));
4751		}
4752	+
4753		public boolean remove(Object o) {
4754	<	return ConcurrentHashMap.this.remove(o) != null;
4754	>	Object k, v; Map.Entry<?,?> e;
4755	>	return ((o instanceof Map.Entry) &&
4756	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4757	>	(v = e.getValue()) != null &&
4758	>	map.remove(k, v));
4759	>	}
4760	>
4761	>	/**
4762	>	* @return an iterator over the entries of the backing map
4763	>	*/
4764	>	public Iterator<Map.Entry<K,V>> iterator() {
4765	>	ConcurrentHashMap<K,V> m = map;
4766	>	Node<K,V>[] t;
4767	>	int f = (t = m.table) == null ? 0 : t.length;
4768	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4769		}
4770	<	public void clear() {
4771	<	ConcurrentHashMap.this.clear();
4770	>
4771	>	public boolean add(Entry<K,V> e) {
4772	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4773		}
4774	+
4775	+	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4776	+	boolean added = false;
4777	+	for (Entry<K,V> e : c) {
4778	+	if (add(e))
4779	+	added = true;
4780	+	}
4781	+	return added;
4782	+	}
4783	+
4784	+	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4785	+	return map.removeEntryIf(filter);
4786	+	}
4787	+
4788	+	public final int hashCode() {
4789	+	int h = 0;
4790	+	Node<K,V>[] t;
4791	+	if ((t = map.table) != null) {
4792	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4793	+	for (Node<K,V> p; (p = it.advance()) != null; ) {
4794	+	h += p.hashCode();
4795	+	}
4796	+	}
4797	+	return h;
4798	+	}
4799	+
4800	+	public final boolean equals(Object o) {
4801	+	Set<?> c;
4802	+	return ((o instanceof Set) &&
4803	+	((c = (Set<?>)o) == this ||
4804	+	(containsAll(c) && c.containsAll(this))));
4805	+	}
4806	+
4807	+	public Spliterator<Map.Entry<K,V>> spliterator() {
4808	+	Node<K,V>[] t;
4809	+	ConcurrentHashMap<K,V> m = map;
4810	+	long n = m.sumCount();
4811	+	int f = (t = m.table) == null ? 0 : t.length;
4812	+	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4813	+	}
4814	+
4815	+	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4816	+	if (action == null) throw new NullPointerException();
4817	+	Node<K,V>[] t;
4818	+	if ((t = map.table) != null) {
4819	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4820	+	for (Node<K,V> p; (p = it.advance()) != null; )
4821	+	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4822	+	}
4823	+	}
4824	+
4825		}
4826
4827	<	private class Values extends AbstractCollection<V> {
4828	<	public Iterator<V> iterator() {
4829	<	return new ValueIterator();
4827	>	// -------------------------------------------------------
4828	>
4829	>	/**
4830	>	* Base class for bulk tasks. Repeats some fields and code from
4831	>	* class Traverser, because we need to subclass CountedCompleter.
4832	>	*/
4833	>	@SuppressWarnings("serial")
4834	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4835	>	Node<K,V>[] tab;        // same as Traverser
4836	>	Node<K,V> next;
4837	>	TableStack<K,V> stack, spare;
4838	>	int index;
4839	>	int baseIndex;
4840	>	int baseLimit;
4841	>	final int baseSize;
4842	>	int batch;              // split control
4843	>
4844	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4845	>	super(par);
4846	>	this.batch = b;
4847	>	this.index = this.baseIndex = i;
4848	>	if ((this.tab = t) == null)
4849	>	this.baseSize = this.baseLimit = 0;
4850	>	else if (par == null)
4851	>	this.baseSize = this.baseLimit = t.length;
4852	>	else {
4853	>	this.baseLimit = f;
4854	>	this.baseSize = par.baseSize;
4855	>	}
4856		}
4857	<	public int size() {
4858	<	return ConcurrentHashMap.this.size();
4857	>
4858	>	/**
4859	>	* Same as Traverser version
4860	>	*/
4861	>	final Node<K,V> advance() {
4862	>	Node<K,V> e;
4863	>	if ((e = next) != null)
4864	>	e = e.next;
4865	>	for (;;) {
4866	>	Node<K,V>[] t; int i, n;
4867	>	if (e != null)
4868	>	return next = e;
4869	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4870	>	(n = t.length) <= (i = index) || i < 0)
4871	>	return next = null;
4872	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4873	>	if (e instanceof ForwardingNode) {
4874	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4875	>	e = null;
4876	>	pushState(t, i, n);
4877	>	continue;
4878	>	}
4879	>	else if (e instanceof TreeBin)
4880	>	e = ((TreeBin<K,V>)e).first;
4881	>	else
4882	>	e = null;
4883	>	}
4884	>	if (stack != null)
4885	>	recoverState(n);
4886	>	else if ((index = i + baseSize) >= n)
4887	>	index = ++baseIndex;
4888	>	}
4889		}
4890	<	public boolean contains(Object o) {
4891	<	return ConcurrentHashMap.this.containsValue(o);
4890	>
4891	>	private void pushState(Node<K,V>[] t, int i, int n) {
4892	>	TableStack<K,V> s = spare;
4893	>	if (s != null)
4894	>	spare = s.next;
4895	>	else
4896	>	s = new TableStack<K,V>();
4897	>	s.tab = t;
4898	>	s.length = n;
4899	>	s.index = i;
4900	>	s.next = stack;
4901	>	stack = s;
4902	>	}
4903	>
4904	>	private void recoverState(int n) {
4905	>	TableStack<K,V> s; int len;
4906	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4907	>	n = len;
4908	>	index = s.index;
4909	>	tab = s.tab;
4910	>	s.tab = null;
4911	>	TableStack<K,V> next = s.next;
4912	>	s.next = spare; // save for reuse
4913	>	stack = next;
4914	>	spare = s;
4915	>	}
4916	>	if (s == null && (index += baseSize) >= n)
4917	>	index = ++baseIndex;
4918		}
4919	<	public void clear() {
4920	<	ConcurrentHashMap.this.clear();
4919	>	}
4920	>
4921	>	/*
4922	>	* Task classes. Coded in a regular but ugly format/style to
4923	>	* simplify checks that each variant differs in the right way from
4924	>	* others. The null screenings exist because compilers cannot tell
4925	>	* that we've already null-checked task arguments, so we force
4926	>	* simplest hoisted bypass to help avoid convoluted traps.
4927	>	*/
4928	>	@SuppressWarnings("serial")
4929	>	static final class ForEachKeyTask<K,V>
4930	>	extends BulkTask<K,V,Void> {
4931	>	final Consumer<? super K> action;
4932	>	ForEachKeyTask
4933	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4934	>	Consumer<? super K> action) {
4935	>	super(p, b, i, f, t);
4936	>	this.action = action;
4937	>	}
4938	>	public final void compute() {
4939	>	final Consumer<? super K> action;
4940	>	if ((action = this.action) != null) {
4941	>	for (int i = baseIndex, f, h; batch > 0 &&
4942	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4943	>	addToPendingCount(1);
4944	>	new ForEachKeyTask<K,V>
4945	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4946	>	action).fork();
4947	>	}
4948	>	for (Node<K,V> p; (p = advance()) != null;)
4949	>	action.accept(p.key);
4950	>	propagateCompletion();
4951	>	}
4952		}
4953		}
4954
4955	<	private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4956	<	public Iterator<Map.Entry<K,V>> iterator() {
4957	<	return new EntryIterator();
4955	>	@SuppressWarnings("serial")
4956	>	static final class ForEachValueTask<K,V>
4957	>	extends BulkTask<K,V,Void> {
4958	>	final Consumer<? super V> action;
4959	>	ForEachValueTask
4960	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4961	>	Consumer<? super V> action) {
4962	>	super(p, b, i, f, t);
4963	>	this.action = action;
4964	>	}
4965	>	public final void compute() {
4966	>	final Consumer<? super V> action;
4967	>	if ((action = this.action) != null) {
4968	>	for (int i = baseIndex, f, h; batch > 0 &&
4969	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4970	>	addToPendingCount(1);
4971	>	new ForEachValueTask<K,V>
4972	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4973	>	action).fork();
4974	>	}
4975	>	for (Node<K,V> p; (p = advance()) != null;)
4976	>	action.accept(p.val);
4977	>	propagateCompletion();
4978	>	}
4979		}
4980	<	public boolean contains(Object o) {
4981	<	if (!(o instanceof Map.Entry))
4982	<	return false;
4983	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
4984	<	V v = ConcurrentHashMap.this.get(e.getKey());
4985	<	return v != null && v.equals(e.getValue());
4980	>	}
4981	>
4982	>	@SuppressWarnings("serial")
4983	>	static final class ForEachEntryTask<K,V>
4984	>	extends BulkTask<K,V,Void> {
4985	>	final Consumer<? super Entry<K,V>> action;
4986	>	ForEachEntryTask
4987	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4988	>	Consumer<? super Entry<K,V>> action) {
4989	>	super(p, b, i, f, t);
4990	>	this.action = action;
4991	>	}
4992	>	public final void compute() {
4993	>	final Consumer<? super Entry<K,V>> action;
4994	>	if ((action = this.action) != null) {
4995	>	for (int i = baseIndex, f, h; batch > 0 &&
4996	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4997	>	addToPendingCount(1);
4998	>	new ForEachEntryTask<K,V>
4999	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5000	>	action).fork();
5001	>	}
5002	>	for (Node<K,V> p; (p = advance()) != null; )
5003	>	action.accept(p);
5004	>	propagateCompletion();
5005	>	}
5006		}
5007	<	public boolean remove(Object o) {
5008	<	if (!(o instanceof Map.Entry))
5009	<	return false;
5010	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5011	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
5007	>	}
5008	>
5009	>	@SuppressWarnings("serial")
5010	>	static final class ForEachMappingTask<K,V>
5011	>	extends BulkTask<K,V,Void> {
5012	>	final BiConsumer<? super K, ? super V> action;
5013	>	ForEachMappingTask
5014	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5015	>	BiConsumer<? super K,? super V> action) {
5016	>	super(p, b, i, f, t);
5017	>	this.action = action;
5018	>	}
5019	>	public final void compute() {
5020	>	final BiConsumer<? super K, ? super V> action;
5021	>	if ((action = this.action) != null) {
5022	>	for (int i = baseIndex, f, h; batch > 0 &&
5023	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5024	>	addToPendingCount(1);
5025	>	new ForEachMappingTask<K,V>
5026	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5027	>	action).fork();
5028	>	}
5029	>	for (Node<K,V> p; (p = advance()) != null; )
5030	>	action.accept(p.key, p.val);
5031	>	propagateCompletion();
5032	>	}
5033		}
5034	<	public int size() {
5035	<	return ConcurrentHashMap.this.size();
5034	>	}
5035	>
5036	>	@SuppressWarnings("serial")
5037	>	static final class ForEachTransformedKeyTask<K,V,U>
5038	>	extends BulkTask<K,V,Void> {
5039	>	final Function<? super K, ? extends U> transformer;
5040	>	final Consumer<? super U> action;
5041	>	ForEachTransformedKeyTask
5042	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5043	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5044	>	super(p, b, i, f, t);
5045	>	this.transformer = transformer; this.action = action;
5046	>	}
5047	>	public final void compute() {
5048	>	final Function<? super K, ? extends U> transformer;
5049	>	final Consumer<? super U> action;
5050	>	if ((transformer = this.transformer) != null &&
5051	>	(action = this.action) != null) {
5052	>	for (int i = baseIndex, f, h; batch > 0 &&
5053	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5054	>	addToPendingCount(1);
5055	>	new ForEachTransformedKeyTask<K,V,U>
5056	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5057	>	transformer, action).fork();
5058	>	}
5059	>	for (Node<K,V> p; (p = advance()) != null; ) {
5060	>	U u;
5061	>	if ((u = transformer.apply(p.key)) != null)
5062	>	action.accept(u);
5063	>	}
5064	>	propagateCompletion();
5065	>	}
5066		}
5067	<	public void clear() {
5068	<	ConcurrentHashMap.this.clear();
5067	>	}
5068	>
5069	>	@SuppressWarnings("serial")
5070	>	static final class ForEachTransformedValueTask<K,V,U>
5071	>	extends BulkTask<K,V,Void> {
5072	>	final Function<? super V, ? extends U> transformer;
5073	>	final Consumer<? super U> action;
5074	>	ForEachTransformedValueTask
5075	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5076	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5077	>	super(p, b, i, f, t);
5078	>	this.transformer = transformer; this.action = action;
5079	>	}
5080	>	public final void compute() {
5081	>	final Function<? super V, ? extends U> transformer;
5082	>	final Consumer<? super U> action;
5083	>	if ((transformer = this.transformer) != null &&
5084	>	(action = this.action) != null) {
5085	>	for (int i = baseIndex, f, h; batch > 0 &&
5086	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5087	>	addToPendingCount(1);
5088	>	new ForEachTransformedValueTask<K,V,U>
5089	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5090	>	transformer, action).fork();
5091	>	}
5092	>	for (Node<K,V> p; (p = advance()) != null; ) {
5093	>	U u;
5094	>	if ((u = transformer.apply(p.val)) != null)
5095	>	action.accept(u);
5096	>	}
5097	>	propagateCompletion();
5098	>	}
5099		}
5100	<	public Object[] toArray() {
5101	<	// Since we don't ordinarily have distinct Entry objects, we
5102	<	// must pack elements using exportable SimpleEntry
5103	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
5104	<	for (Iterator<Map.Entry<K,V>> i = iterator(); i.hasNext(); )
5105	<	c.add(new SimpleEntry<K,V>(i.next()));
5106	<	return c.toArray();
5100	>	}
5101	>
5102	>	@SuppressWarnings("serial")
5103	>	static final class ForEachTransformedEntryTask<K,V,U>
5104	>	extends BulkTask<K,V,Void> {
5105	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5106	>	final Consumer<? super U> action;
5107	>	ForEachTransformedEntryTask
5108	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5109	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5110	>	super(p, b, i, f, t);
5111	>	this.transformer = transformer; this.action = action;
5112	>	}
5113	>	public final void compute() {
5114	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5115	>	final Consumer<? super U> action;
5116	>	if ((transformer = this.transformer) != null &&
5117	>	(action = this.action) != null) {
5118	>	for (int i = baseIndex, f, h; batch > 0 &&
5119	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5120	>	addToPendingCount(1);
5121	>	new ForEachTransformedEntryTask<K,V,U>
5122	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5123	>	transformer, action).fork();
5124	>	}
5125	>	for (Node<K,V> p; (p = advance()) != null; ) {
5126	>	U u;
5127	>	if ((u = transformer.apply(p)) != null)
5128	>	action.accept(u);
5129	>	}
5130	>	propagateCompletion();
5131	>	}
5132		}
5133	<	public <T> T[] toArray(T[] a) {
5134	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
5135	<	for (Iterator<Map.Entry<K,V>> i = iterator(); i.hasNext(); )
5136	<	c.add(new SimpleEntry<K,V>(i.next()));
5137	<	return c.toArray(a);
5133	>	}
5134	>
5135	>	@SuppressWarnings("serial")
5136	>	static final class ForEachTransformedMappingTask<K,V,U>
5137	>	extends BulkTask<K,V,Void> {
5138	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5139	>	final Consumer<? super U> action;
5140	>	ForEachTransformedMappingTask
5141	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5142	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5143	>	Consumer<? super U> action) {
5144	>	super(p, b, i, f, t);
5145	>	this.transformer = transformer; this.action = action;
5146	>	}
5147	>	public final void compute() {
5148	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5149	>	final Consumer<? super U> action;
5150	>	if ((transformer = this.transformer) != null &&
5151	>	(action = this.action) != null) {
5152	>	for (int i = baseIndex, f, h; batch > 0 &&
5153	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5154	>	addToPendingCount(1);
5155	>	new ForEachTransformedMappingTask<K,V,U>
5156	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5157	>	transformer, action).fork();
5158	>	}
5159	>	for (Node<K,V> p; (p = advance()) != null; ) {
5160	>	U u;
5161	>	if ((u = transformer.apply(p.key, p.val)) != null)
5162	>	action.accept(u);
5163	>	}
5164	>	propagateCompletion();
5165	>	}
5166		}
5167	+	}
5168
5169	+	@SuppressWarnings("serial")
5170	+	static final class SearchKeysTask<K,V,U>
5171	+	extends BulkTask<K,V,U> {
5172	+	final Function<? super K, ? extends U> searchFunction;
5173	+	final AtomicReference<U> result;
5174	+	SearchKeysTask
5175	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5176	+	Function<? super K, ? extends U> searchFunction,
5177	+	AtomicReference<U> result) {
5178	+	super(p, b, i, f, t);
5179	+	this.searchFunction = searchFunction; this.result = result;
5180	+	}
5181	+	public final U getRawResult() { return result.get(); }
5182	+	public final void compute() {
5183	+	final Function<? super K, ? extends U> searchFunction;
5184	+	final AtomicReference<U> result;
5185	+	if ((searchFunction = this.searchFunction) != null &&
5186	+	(result = this.result) != null) {
5187	+	for (int i = baseIndex, f, h; batch > 0 &&
5188	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5189	+	if (result.get() != null)
5190	+	return;
5191	+	addToPendingCount(1);
5192	+	new SearchKeysTask<K,V,U>
5193	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5194	+	searchFunction, result).fork();
5195	+	}
5196	+	while (result.get() == null) {
5197	+	U u;
5198	+	Node<K,V> p;
5199	+	if ((p = advance()) == null) {
5200	+	propagateCompletion();
5201	+	break;
5202	+	}
5203	+	if ((u = searchFunction.apply(p.key)) != null) {
5204	+	if (result.compareAndSet(null, u))
5205	+	quietlyCompleteRoot();
5206	+	break;
5207	+	}
5208	+	}
5209	+	}
5210	+	}
5211		}
5212
5213	<	/**
5214	<	* This duplicates java.util.AbstractMap.SimpleEntry until this class
5215	<	* is made accessible.
5216	<	*/
5217	<	static class SimpleEntry<K,V> implements Entry<K,V> {
5218	<	K key;
5219	<	V value;
5213	>	@SuppressWarnings("serial")
5214	>	static final class SearchValuesTask<K,V,U>
5215	>	extends BulkTask<K,V,U> {
5216	>	final Function<? super V, ? extends U> searchFunction;
5217	>	final AtomicReference<U> result;
5218	>	SearchValuesTask
5219	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5220	>	Function<? super V, ? extends U> searchFunction,
5221	>	AtomicReference<U> result) {
5222	>	super(p, b, i, f, t);
5223	>	this.searchFunction = searchFunction; this.result = result;
5224	>	}
5225	>	public final U getRawResult() { return result.get(); }
5226	>	public final void compute() {
5227	>	final Function<? super V, ? extends U> searchFunction;
5228	>	final AtomicReference<U> result;
5229	>	if ((searchFunction = this.searchFunction) != null &&
5230	>	(result = this.result) != null) {
5231	>	for (int i = baseIndex, f, h; batch > 0 &&
5232	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5233	>	if (result.get() != null)
5234	>	return;
5235	>	addToPendingCount(1);
5236	>	new SearchValuesTask<K,V,U>
5237	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5238	>	searchFunction, result).fork();
5239	>	}
5240	>	while (result.get() == null) {
5241	>	U u;
5242	>	Node<K,V> p;
5243	>	if ((p = advance()) == null) {
5244	>	propagateCompletion();
5245	>	break;
5246	>	}
5247	>	if ((u = searchFunction.apply(p.val)) != null) {
5248	>	if (result.compareAndSet(null, u))
5249	>	quietlyCompleteRoot();
5250	>	break;
5251	>	}
5252	>	}
5253	>	}
5254	>	}
5255	>	}
5256
5257	<	public SimpleEntry(K key, V value) {
5258	<	this.key   = key;
5259	<	this.value = value;
5260	<	}
5257	>	@SuppressWarnings("serial")
5258	>	static final class SearchEntriesTask<K,V,U>
5259	>	extends BulkTask<K,V,U> {
5260	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5261	>	final AtomicReference<U> result;
5262	>	SearchEntriesTask
5263	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5264	>	Function<Entry<K,V>, ? extends U> searchFunction,
5265	>	AtomicReference<U> result) {
5266	>	super(p, b, i, f, t);
5267	>	this.searchFunction = searchFunction; this.result = result;
5268	>	}
5269	>	public final U getRawResult() { return result.get(); }
5270	>	public final void compute() {
5271	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5272	>	final AtomicReference<U> result;
5273	>	if ((searchFunction = this.searchFunction) != null &&
5274	>	(result = this.result) != null) {
5275	>	for (int i = baseIndex, f, h; batch > 0 &&
5276	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5277	>	if (result.get() != null)
5278	>	return;
5279	>	addToPendingCount(1);
5280	>	new SearchEntriesTask<K,V,U>
5281	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5282	>	searchFunction, result).fork();
5283	>	}
5284	>	while (result.get() == null) {
5285	>	U u;
5286	>	Node<K,V> p;
5287	>	if ((p = advance()) == null) {
5288	>	propagateCompletion();
5289	>	break;
5290	>	}
5291	>	if ((u = searchFunction.apply(p)) != null) {
5292	>	if (result.compareAndSet(null, u))
5293	>	quietlyCompleteRoot();
5294	>	return;
5295	>	}
5296	>	}
5297	>	}
5298	>	}
5299	>	}
5300
5301	<	public SimpleEntry(Entry<K,V> e) {
5302	<	this.key   = e.getKey();
5303	<	this.value = e.getValue();
5304	<	}
5301	>	@SuppressWarnings("serial")
5302	>	static final class SearchMappingsTask<K,V,U>
5303	>	extends BulkTask<K,V,U> {
5304	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5305	>	final AtomicReference<U> result;
5306	>	SearchMappingsTask
5307	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5308	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5309	>	AtomicReference<U> result) {
5310	>	super(p, b, i, f, t);
5311	>	this.searchFunction = searchFunction; this.result = result;
5312	>	}
5313	>	public final U getRawResult() { return result.get(); }
5314	>	public final void compute() {
5315	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5316	>	final AtomicReference<U> result;
5317	>	if ((searchFunction = this.searchFunction) != null &&
5318	>	(result = this.result) != null) {
5319	>	for (int i = baseIndex, f, h; batch > 0 &&
5320	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5321	>	if (result.get() != null)
5322	>	return;
5323	>	addToPendingCount(1);
5324	>	new SearchMappingsTask<K,V,U>
5325	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5326	>	searchFunction, result).fork();
5327	>	}
5328	>	while (result.get() == null) {
5329	>	U u;
5330	>	Node<K,V> p;
5331	>	if ((p = advance()) == null) {
5332	>	propagateCompletion();
5333	>	break;
5334	>	}
5335	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5336	>	if (result.compareAndSet(null, u))
5337	>	quietlyCompleteRoot();
5338	>	break;
5339	>	}
5340	>	}
5341	>	}
5342	>	}
5343	>	}
5344
5345	<	public K getKey() {
5346	<	return key;
5347	<	}
5345	>	@SuppressWarnings("serial")
5346	>	static final class ReduceKeysTask<K,V>
5347	>	extends BulkTask<K,V,K> {
5348	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5349	>	K result;
5350	>	ReduceKeysTask<K,V> rights, nextRight;
5351	>	ReduceKeysTask
5352	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5353	>	ReduceKeysTask<K,V> nextRight,
5354	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5355	>	super(p, b, i, f, t); this.nextRight = nextRight;
5356	>	this.reducer = reducer;
5357	>	}
5358	>	public final K getRawResult() { return result; }
5359	>	public final void compute() {
5360	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5361	>	if ((reducer = this.reducer) != null) {
5362	>	for (int i = baseIndex, f, h; batch > 0 &&
5363	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5364	>	addToPendingCount(1);
5365	>	(rights = new ReduceKeysTask<K,V>
5366	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5367	>	rights, reducer)).fork();
5368	>	}
5369	>	K r = null;
5370	>	for (Node<K,V> p; (p = advance()) != null; ) {
5371	>	K u = p.key;
5372	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5373	>	}
5374	>	result = r;
5375	>	CountedCompleter<?> c;
5376	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5377	>	@SuppressWarnings("unchecked")
5378	>	ReduceKeysTask<K,V>
5379	>	t = (ReduceKeysTask<K,V>)c,
5380	>	s = t.rights;
5381	>	while (s != null) {
5382	>	K tr, sr;
5383	>	if ((sr = s.result) != null)
5384	>	t.result = (((tr = t.result) == null) ? sr :
5385	>	reducer.apply(tr, sr));
5386	>	s = t.rights = s.nextRight;
5387	>	}
5388	>	}
5389	>	}
5390	>	}
5391	>	}
5392
5393	<	public V getValue() {
5394	<	return value;
5395	<	}
5393	>	@SuppressWarnings("serial")
5394	>	static final class ReduceValuesTask<K,V>
5395	>	extends BulkTask<K,V,V> {
5396	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5397	>	V result;
5398	>	ReduceValuesTask<K,V> rights, nextRight;
5399	>	ReduceValuesTask
5400	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5401	>	ReduceValuesTask<K,V> nextRight,
5402	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5403	>	super(p, b, i, f, t); this.nextRight = nextRight;
5404	>	this.reducer = reducer;
5405	>	}
5406	>	public final V getRawResult() { return result; }
5407	>	public final void compute() {
5408	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5409	>	if ((reducer = this.reducer) != null) {
5410	>	for (int i = baseIndex, f, h; batch > 0 &&
5411	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5412	>	addToPendingCount(1);
5413	>	(rights = new ReduceValuesTask<K,V>
5414	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5415	>	rights, reducer)).fork();
5416	>	}
5417	>	V r = null;
5418	>	for (Node<K,V> p; (p = advance()) != null; ) {
5419	>	V v = p.val;
5420	>	r = (r == null) ? v : reducer.apply(r, v);
5421	>	}
5422	>	result = r;
5423	>	CountedCompleter<?> c;
5424	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5425	>	@SuppressWarnings("unchecked")
5426	>	ReduceValuesTask<K,V>
5427	>	t = (ReduceValuesTask<K,V>)c,
5428	>	s = t.rights;
5429	>	while (s != null) {
5430	>	V tr, sr;
5431	>	if ((sr = s.result) != null)
5432	>	t.result = (((tr = t.result) == null) ? sr :
5433	>	reducer.apply(tr, sr));
5434	>	s = t.rights = s.nextRight;
5435	>	}
5436	>	}
5437	>	}
5438	>	}
5439	>	}
5440
5441	<	public V setValue(V value) {
5442	<	V oldValue = this.value;
5443	<	this.value = value;
5444	<	return oldValue;
5445	<	}
5441	>	@SuppressWarnings("serial")
5442	>	static final class ReduceEntriesTask<K,V>
5443	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5444	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5445	>	Map.Entry<K,V> result;
5446	>	ReduceEntriesTask<K,V> rights, nextRight;
5447	>	ReduceEntriesTask
5448	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5449	>	ReduceEntriesTask<K,V> nextRight,
5450	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5451	>	super(p, b, i, f, t); this.nextRight = nextRight;
5452	>	this.reducer = reducer;
5453	>	}
5454	>	public final Map.Entry<K,V> getRawResult() { return result; }
5455	>	public final void compute() {
5456	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5457	>	if ((reducer = this.reducer) != null) {
5458	>	for (int i = baseIndex, f, h; batch > 0 &&
5459	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5460	>	addToPendingCount(1);
5461	>	(rights = new ReduceEntriesTask<K,V>
5462	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5463	>	rights, reducer)).fork();
5464	>	}
5465	>	Map.Entry<K,V> r = null;
5466	>	for (Node<K,V> p; (p = advance()) != null; )
5467	>	r = (r == null) ? p : reducer.apply(r, p);
5468	>	result = r;
5469	>	CountedCompleter<?> c;
5470	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5471	>	@SuppressWarnings("unchecked")
5472	>	ReduceEntriesTask<K,V>
5473	>	t = (ReduceEntriesTask<K,V>)c,
5474	>	s = t.rights;
5475	>	while (s != null) {
5476	>	Map.Entry<K,V> tr, sr;
5477	>	if ((sr = s.result) != null)
5478	>	t.result = (((tr = t.result) == null) ? sr :
5479	>	reducer.apply(tr, sr));
5480	>	s = t.rights = s.nextRight;
5481	>	}
5482	>	}
5483	>	}
5484	>	}
5485	>	}
5486
5487	<	public boolean equals(Object o) {
5488	<	if (!(o instanceof Map.Entry))
5489	<	return false;
5490	<	Map.Entry e = (Map.Entry)o;
5491	<	return eq(key, e.getKey()) && eq(value, e.getValue());
5492	<	}
5487	>	@SuppressWarnings("serial")
5488	>	static final class MapReduceKeysTask<K,V,U>
5489	>	extends BulkTask<K,V,U> {
5490	>	final Function<? super K, ? extends U> transformer;
5491	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5492	>	U result;
5493	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5494	>	MapReduceKeysTask
5495	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5496	>	MapReduceKeysTask<K,V,U> nextRight,
5497	>	Function<? super K, ? extends U> transformer,
5498	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5499	>	super(p, b, i, f, t); this.nextRight = nextRight;
5500	>	this.transformer = transformer;
5501	>	this.reducer = reducer;
5502	>	}
5503	>	public final U getRawResult() { return result; }
5504	>	public final void compute() {
5505	>	final Function<? super K, ? extends U> transformer;
5506	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5507	>	if ((transformer = this.transformer) != null &&
5508	>	(reducer = this.reducer) != null) {
5509	>	for (int i = baseIndex, f, h; batch > 0 &&
5510	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5511	>	addToPendingCount(1);
5512	>	(rights = new MapReduceKeysTask<K,V,U>
5513	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5514	>	rights, transformer, reducer)).fork();
5515	>	}
5516	>	U r = null;
5517	>	for (Node<K,V> p; (p = advance()) != null; ) {
5518	>	U u;
5519	>	if ((u = transformer.apply(p.key)) != null)
5520	>	r = (r == null) ? u : reducer.apply(r, u);
5521	>	}
5522	>	result = r;
5523	>	CountedCompleter<?> c;
5524	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5525	>	@SuppressWarnings("unchecked")
5526	>	MapReduceKeysTask<K,V,U>
5527	>	t = (MapReduceKeysTask<K,V,U>)c,
5528	>	s = t.rights;
5529	>	while (s != null) {
5530	>	U tr, sr;
5531	>	if ((sr = s.result) != null)
5532	>	t.result = (((tr = t.result) == null) ? sr :
5533	>	reducer.apply(tr, sr));
5534	>	s = t.rights = s.nextRight;
5535	>	}
5536	>	}
5537	>	}
5538	>	}
5539	>	}
5540
5541	<	public int hashCode() {
5542	<	return ((key   == null)   ? 0 :   key.hashCode()) ^
5543	<	((value == null)   ? 0 : value.hashCode());
5544	<	}
5541	>	@SuppressWarnings("serial")
5542	>	static final class MapReduceValuesTask<K,V,U>
5543	>	extends BulkTask<K,V,U> {
5544	>	final Function<? super V, ? extends U> transformer;
5545	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5546	>	U result;
5547	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5548	>	MapReduceValuesTask
5549	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5550	>	MapReduceValuesTask<K,V,U> nextRight,
5551	>	Function<? super V, ? extends U> transformer,
5552	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5553	>	super(p, b, i, f, t); this.nextRight = nextRight;
5554	>	this.transformer = transformer;
5555	>	this.reducer = reducer;
5556	>	}
5557	>	public final U getRawResult() { return result; }
5558	>	public final void compute() {
5559	>	final Function<? super V, ? extends U> transformer;
5560	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5561	>	if ((transformer = this.transformer) != null &&
5562	>	(reducer = this.reducer) != null) {
5563	>	for (int i = baseIndex, f, h; batch > 0 &&
5564	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5565	>	addToPendingCount(1);
5566	>	(rights = new MapReduceValuesTask<K,V,U>
5567	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5568	>	rights, transformer, reducer)).fork();
5569	>	}
5570	>	U r = null;
5571	>	for (Node<K,V> p; (p = advance()) != null; ) {
5572	>	U u;
5573	>	if ((u = transformer.apply(p.val)) != null)
5574	>	r = (r == null) ? u : reducer.apply(r, u);
5575	>	}
5576	>	result = r;
5577	>	CountedCompleter<?> c;
5578	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5579	>	@SuppressWarnings("unchecked")
5580	>	MapReduceValuesTask<K,V,U>
5581	>	t = (MapReduceValuesTask<K,V,U>)c,
5582	>	s = t.rights;
5583	>	while (s != null) {
5584	>	U tr, sr;
5585	>	if ((sr = s.result) != null)
5586	>	t.result = (((tr = t.result) == null) ? sr :
5587	>	reducer.apply(tr, sr));
5588	>	s = t.rights = s.nextRight;
5589	>	}
5590	>	}
5591	>	}
5592	>	}
5593	>	}
5594
5595	<	public String toString() {
5596	<	return key + "=" + value;
5597	<	}
5595	>	@SuppressWarnings("serial")
5596	>	static final class MapReduceEntriesTask<K,V,U>
5597	>	extends BulkTask<K,V,U> {
5598	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5599	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5600	>	U result;
5601	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5602	>	MapReduceEntriesTask
5603	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5604	>	MapReduceEntriesTask<K,V,U> nextRight,
5605	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5606	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5607	>	super(p, b, i, f, t); this.nextRight = nextRight;
5608	>	this.transformer = transformer;
5609	>	this.reducer = reducer;
5610	>	}
5611	>	public final U getRawResult() { return result; }
5612	>	public final void compute() {
5613	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5614	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5615	>	if ((transformer = this.transformer) != null &&
5616	>	(reducer = this.reducer) != null) {
5617	>	for (int i = baseIndex, f, h; batch > 0 &&
5618	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5619	>	addToPendingCount(1);
5620	>	(rights = new MapReduceEntriesTask<K,V,U>
5621	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5622	>	rights, transformer, reducer)).fork();
5623	>	}
5624	>	U r = null;
5625	>	for (Node<K,V> p; (p = advance()) != null; ) {
5626	>	U u;
5627	>	if ((u = transformer.apply(p)) != null)
5628	>	r = (r == null) ? u : reducer.apply(r, u);
5629	>	}
5630	>	result = r;
5631	>	CountedCompleter<?> c;
5632	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5633	>	@SuppressWarnings("unchecked")
5634	>	MapReduceEntriesTask<K,V,U>
5635	>	t = (MapReduceEntriesTask<K,V,U>)c,
5636	>	s = t.rights;
5637	>	while (s != null) {
5638	>	U tr, sr;
5639	>	if ((sr = s.result) != null)
5640	>	t.result = (((tr = t.result) == null) ? sr :
5641	>	reducer.apply(tr, sr));
5642	>	s = t.rights = s.nextRight;
5643	>	}
5644	>	}
5645	>	}
5646	>	}
5647	>	}
5648
5649	<	private static boolean eq(Object o1, Object o2) {
5650	<	return (o1 == null ? o2 == null : o1.equals(o2));
5649	>	@SuppressWarnings("serial")
5650	>	static final class MapReduceMappingsTask<K,V,U>
5651	>	extends BulkTask<K,V,U> {
5652	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5653	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5654	>	U result;
5655	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5656	>	MapReduceMappingsTask
5657	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5658	>	MapReduceMappingsTask<K,V,U> nextRight,
5659	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5660	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5661	>	super(p, b, i, f, t); this.nextRight = nextRight;
5662	>	this.transformer = transformer;
5663	>	this.reducer = reducer;
5664	>	}
5665	>	public final U getRawResult() { return result; }
5666	>	public final void compute() {
5667	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5668	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5669	>	if ((transformer = this.transformer) != null &&
5670	>	(reducer = this.reducer) != null) {
5671	>	for (int i = baseIndex, f, h; batch > 0 &&
5672	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5673	>	addToPendingCount(1);
5674	>	(rights = new MapReduceMappingsTask<K,V,U>
5675	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5676	>	rights, transformer, reducer)).fork();
5677	>	}
5678	>	U r = null;
5679	>	for (Node<K,V> p; (p = advance()) != null; ) {
5680	>	U u;
5681	>	if ((u = transformer.apply(p.key, p.val)) != null)
5682	>	r = (r == null) ? u : reducer.apply(r, u);
5683	>	}
5684	>	result = r;
5685	>	CountedCompleter<?> c;
5686	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5687	>	@SuppressWarnings("unchecked")
5688	>	MapReduceMappingsTask<K,V,U>
5689	>	t = (MapReduceMappingsTask<K,V,U>)c,
5690	>	s = t.rights;
5691	>	while (s != null) {
5692	>	U tr, sr;
5693	>	if ((sr = s.result) != null)
5694	>	t.result = (((tr = t.result) == null) ? sr :
5695	>	reducer.apply(tr, sr));
5696	>	s = t.rights = s.nextRight;
5697	>	}
5698	>	}
5699	>	}
5700		}
5701		}
5702
5703	<	/* ---------------- Serialization Support -------------- */
5703	>	@SuppressWarnings("serial")
5704	>	static final class MapReduceKeysToDoubleTask<K,V>
5705	>	extends BulkTask<K,V,Double> {
5706	>	final ToDoubleFunction<? super K> transformer;
5707	>	final DoubleBinaryOperator reducer;
5708	>	final double basis;
5709	>	double result;
5710	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5711	>	MapReduceKeysToDoubleTask
5712	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5713	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5714	>	ToDoubleFunction<? super K> transformer,
5715	>	double basis,
5716	>	DoubleBinaryOperator reducer) {
5717	>	super(p, b, i, f, t); this.nextRight = nextRight;
5718	>	this.transformer = transformer;
5719	>	this.basis = basis; this.reducer = reducer;
5720	>	}
5721	>	public final Double getRawResult() { return result; }
5722	>	public final void compute() {
5723	>	final ToDoubleFunction<? super K> transformer;
5724	>	final DoubleBinaryOperator reducer;
5725	>	if ((transformer = this.transformer) != null &&
5726	>	(reducer = this.reducer) != null) {
5727	>	double r = this.basis;
5728	>	for (int i = baseIndex, f, h; batch > 0 &&
5729	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5730	>	addToPendingCount(1);
5731	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5732	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5733	>	rights, transformer, r, reducer)).fork();
5734	>	}
5735	>	for (Node<K,V> p; (p = advance()) != null; )
5736	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5737	>	result = r;
5738	>	CountedCompleter<?> c;
5739	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5740	>	@SuppressWarnings("unchecked")
5741	>	MapReduceKeysToDoubleTask<K,V>
5742	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5743	>	s = t.rights;
5744	>	while (s != null) {
5745	>	t.result = reducer.applyAsDouble(t.result, s.result);
5746	>	s = t.rights = s.nextRight;
5747	>	}
5748	>	}
5749	>	}
5750	>	}
5751	>	}
5752
5753	<	/**
5754	<	* Save the state of the <tt>ConcurrentHashMap</tt>
5755	<	* instance to a stream (i.e.,
5756	<	* serialize it).
5757	<	* @param s the stream
5758	<	* @serialData
5759	<	* the key (Object) and value (Object)
5760	<	* for each key-value mapping, followed by a null pair.
5761	<	* The key-value mappings are emitted in no particular order.
5762	<	*/
5763	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
5764	<	s.defaultWriteObject();
5753	>	@SuppressWarnings("serial")
5754	>	static final class MapReduceValuesToDoubleTask<K,V>
5755	>	extends BulkTask<K,V,Double> {
5756	>	final ToDoubleFunction<? super V> transformer;
5757	>	final DoubleBinaryOperator reducer;
5758	>	final double basis;
5759	>	double result;
5760	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5761	>	MapReduceValuesToDoubleTask
5762	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5763	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5764	>	ToDoubleFunction<? super V> transformer,
5765	>	double basis,
5766	>	DoubleBinaryOperator reducer) {
5767	>	super(p, b, i, f, t); this.nextRight = nextRight;
5768	>	this.transformer = transformer;
5769	>	this.basis = basis; this.reducer = reducer;
5770	>	}
5771	>	public final Double getRawResult() { return result; }
5772	>	public final void compute() {
5773	>	final ToDoubleFunction<? super V> transformer;
5774	>	final DoubleBinaryOperator reducer;
5775	>	if ((transformer = this.transformer) != null &&
5776	>	(reducer = this.reducer) != null) {
5777	>	double r = this.basis;
5778	>	for (int i = baseIndex, f, h; batch > 0 &&
5779	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5780	>	addToPendingCount(1);
5781	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5782	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5783	>	rights, transformer, r, reducer)).fork();
5784	>	}
5785	>	for (Node<K,V> p; (p = advance()) != null; )
5786	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5787	>	result = r;
5788	>	CountedCompleter<?> c;
5789	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5790	>	@SuppressWarnings("unchecked")
5791	>	MapReduceValuesToDoubleTask<K,V>
5792	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5793	>	s = t.rights;
5794	>	while (s != null) {
5795	>	t.result = reducer.applyAsDouble(t.result, s.result);
5796	>	s = t.rights = s.nextRight;
5797	>	}
5798	>	}
5799	>	}
5800	>	}
5801	>	}
5802
5803	<	for (int k = 0; k < segments.length; ++k) {
5804	<	Segment<K,V> seg = (Segment<K,V>)segments[k];
5805	<	seg.lock();
5806	<	try {
5807	<	HashEntry[] tab = seg.table;
5808	<	for (int i = 0; i < tab.length; ++i) {
5809	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i]; e != null; e = e.next) {
5810	<	s.writeObject(e.key);
5811	<	s.writeObject(e.value);
5803	>	@SuppressWarnings("serial")
5804	>	static final class MapReduceEntriesToDoubleTask<K,V>
5805	>	extends BulkTask<K,V,Double> {
5806	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5807	>	final DoubleBinaryOperator reducer;
5808	>	final double basis;
5809	>	double result;
5810	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5811	>	MapReduceEntriesToDoubleTask
5812	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5813	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5814	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5815	>	double basis,
5816	>	DoubleBinaryOperator reducer) {
5817	>	super(p, b, i, f, t); this.nextRight = nextRight;
5818	>	this.transformer = transformer;
5819	>	this.basis = basis; this.reducer = reducer;
5820	>	}
5821	>	public final Double getRawResult() { return result; }
5822	>	public final void compute() {
5823	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5824	>	final DoubleBinaryOperator reducer;
5825	>	if ((transformer = this.transformer) != null &&
5826	>	(reducer = this.reducer) != null) {
5827	>	double r = this.basis;
5828	>	for (int i = baseIndex, f, h; batch > 0 &&
5829	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5830	>	addToPendingCount(1);
5831	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5832	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5833	>	rights, transformer, r, reducer)).fork();
5834	>	}
5835	>	for (Node<K,V> p; (p = advance()) != null; )
5836	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5837	>	result = r;
5838	>	CountedCompleter<?> c;
5839	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5840	>	@SuppressWarnings("unchecked")
5841	>	MapReduceEntriesToDoubleTask<K,V>
5842	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5843	>	s = t.rights;
5844	>	while (s != null) {
5845	>	t.result = reducer.applyAsDouble(t.result, s.result);
5846	>	s = t.rights = s.nextRight;
5847		}
5848		}
1297	–	} finally {
1298	–	seg.unlock();
5849		}
5850		}
1301	–	s.writeObject(null);
1302	–	s.writeObject(null);
5851		}
5852
5853	<	/**
5854	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
5855	<	* instance from a stream (i.e.,
5856	<	* deserialize it).
5857	<	* @param s the stream
5858	<	*/
5859	<	private void readObject(java.io.ObjectInputStream s)
5860	<	throws IOException, ClassNotFoundException  {
5861	<	s.defaultReadObject();
5853	>	@SuppressWarnings("serial")
5854	>	static final class MapReduceMappingsToDoubleTask<K,V>
5855	>	extends BulkTask<K,V,Double> {
5856	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5857	>	final DoubleBinaryOperator reducer;
5858	>	final double basis;
5859	>	double result;
5860	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5861	>	MapReduceMappingsToDoubleTask
5862	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5863	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5864	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5865	>	double basis,
5866	>	DoubleBinaryOperator reducer) {
5867	>	super(p, b, i, f, t); this.nextRight = nextRight;
5868	>	this.transformer = transformer;
5869	>	this.basis = basis; this.reducer = reducer;
5870	>	}
5871	>	public final Double getRawResult() { return result; }
5872	>	public final void compute() {
5873	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5874	>	final DoubleBinaryOperator reducer;
5875	>	if ((transformer = this.transformer) != null &&
5876	>	(reducer = this.reducer) != null) {
5877	>	double r = this.basis;
5878	>	for (int i = baseIndex, f, h; batch > 0 &&
5879	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5880	>	addToPendingCount(1);
5881	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5882	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5883	>	rights, transformer, r, reducer)).fork();
5884	>	}
5885	>	for (Node<K,V> p; (p = advance()) != null; )
5886	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5887	>	result = r;
5888	>	CountedCompleter<?> c;
5889	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5890	>	@SuppressWarnings("unchecked")
5891	>	MapReduceMappingsToDoubleTask<K,V>
5892	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5893	>	s = t.rights;
5894	>	while (s != null) {
5895	>	t.result = reducer.applyAsDouble(t.result, s.result);
5896	>	s = t.rights = s.nextRight;
5897	>	}
5898	>	}
5899	>	}
5900	>	}
5901	>	}
5902
5903	<	// Initialize each segment to be minimally sized, and let grow.
5904	<	for (int i = 0; i < segments.length; ++i) {
5905	<	segments[i].setTable(new HashEntry[1]);
5903	>	@SuppressWarnings("serial")
5904	>	static final class MapReduceKeysToLongTask<K,V>
5905	>	extends BulkTask<K,V,Long> {
5906	>	final ToLongFunction<? super K> transformer;
5907	>	final LongBinaryOperator reducer;
5908	>	final long basis;
5909	>	long result;
5910	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5911	>	MapReduceKeysToLongTask
5912	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5913	>	MapReduceKeysToLongTask<K,V> nextRight,
5914	>	ToLongFunction<? super K> transformer,
5915	>	long basis,
5916	>	LongBinaryOperator reducer) {
5917	>	super(p, b, i, f, t); this.nextRight = nextRight;
5918	>	this.transformer = transformer;
5919	>	this.basis = basis; this.reducer = reducer;
5920	>	}
5921	>	public final Long getRawResult() { return result; }
5922	>	public final void compute() {
5923	>	final ToLongFunction<? super K> transformer;
5924	>	final LongBinaryOperator reducer;
5925	>	if ((transformer = this.transformer) != null &&
5926	>	(reducer = this.reducer) != null) {
5927	>	long r = this.basis;
5928	>	for (int i = baseIndex, f, h; batch > 0 &&
5929	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5930	>	addToPendingCount(1);
5931	>	(rights = new MapReduceKeysToLongTask<K,V>
5932	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5933	>	rights, transformer, r, reducer)).fork();
5934	>	}
5935	>	for (Node<K,V> p; (p = advance()) != null; )
5936	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5937	>	result = r;
5938	>	CountedCompleter<?> c;
5939	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5940	>	@SuppressWarnings("unchecked")
5941	>	MapReduceKeysToLongTask<K,V>
5942	>	t = (MapReduceKeysToLongTask<K,V>)c,
5943	>	s = t.rights;
5944	>	while (s != null) {
5945	>	t.result = reducer.applyAsLong(t.result, s.result);
5946	>	s = t.rights = s.nextRight;
5947	>	}
5948	>	}
5949	>	}
5950		}
5951	+	}
5952
5953	<	// Read the keys and values, and put the mappings in the table
5954	<	for (;;) {
5955	<	K key = (K) s.readObject();
5956	<	V value = (V) s.readObject();
5957	<	if (key == null)
5958	<	break;
5959	<	put(key, value);
5953	>	@SuppressWarnings("serial")
5954	>	static final class MapReduceValuesToLongTask<K,V>
5955	>	extends BulkTask<K,V,Long> {
5956	>	final ToLongFunction<? super V> transformer;
5957	>	final LongBinaryOperator reducer;
5958	>	final long basis;
5959	>	long result;
5960	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5961	>	MapReduceValuesToLongTask
5962	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5963	>	MapReduceValuesToLongTask<K,V> nextRight,
5964	>	ToLongFunction<? super V> transformer,
5965	>	long basis,
5966	>	LongBinaryOperator reducer) {
5967	>	super(p, b, i, f, t); this.nextRight = nextRight;
5968	>	this.transformer = transformer;
5969	>	this.basis = basis; this.reducer = reducer;
5970	>	}
5971	>	public final Long getRawResult() { return result; }
5972	>	public final void compute() {
5973	>	final ToLongFunction<? super V> transformer;
5974	>	final LongBinaryOperator reducer;
5975	>	if ((transformer = this.transformer) != null &&
5976	>	(reducer = this.reducer) != null) {
5977	>	long r = this.basis;
5978	>	for (int i = baseIndex, f, h; batch > 0 &&
5979	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5980	>	addToPendingCount(1);
5981	>	(rights = new MapReduceValuesToLongTask<K,V>
5982	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5983	>	rights, transformer, r, reducer)).fork();
5984	>	}
5985	>	for (Node<K,V> p; (p = advance()) != null; )
5986	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5987	>	result = r;
5988	>	CountedCompleter<?> c;
5989	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5990	>	@SuppressWarnings("unchecked")
5991	>	MapReduceValuesToLongTask<K,V>
5992	>	t = (MapReduceValuesToLongTask<K,V>)c,
5993	>	s = t.rights;
5994	>	while (s != null) {
5995	>	t.result = reducer.applyAsLong(t.result, s.result);
5996	>	s = t.rights = s.nextRight;
5997	>	}
5998	>	}
5999	>	}
6000		}
6001		}
1329	–	}
6002
6003	+	@SuppressWarnings("serial")
6004	+	static final class MapReduceEntriesToLongTask<K,V>
6005	+	extends BulkTask<K,V,Long> {
6006	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6007	+	final LongBinaryOperator reducer;
6008	+	final long basis;
6009	+	long result;
6010	+	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6011	+	MapReduceEntriesToLongTask
6012	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6013	+	MapReduceEntriesToLongTask<K,V> nextRight,
6014	+	ToLongFunction<Map.Entry<K,V>> transformer,
6015	+	long basis,
6016	+	LongBinaryOperator reducer) {
6017	+	super(p, b, i, f, t); this.nextRight = nextRight;
6018	+	this.transformer = transformer;
6019	+	this.basis = basis; this.reducer = reducer;
6020	+	}
6021	+	public final Long getRawResult() { return result; }
6022	+	public final void compute() {
6023	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6024	+	final LongBinaryOperator reducer;
6025	+	if ((transformer = this.transformer) != null &&
6026	+	(reducer = this.reducer) != null) {
6027	+	long r = this.basis;
6028	+	for (int i = baseIndex, f, h; batch > 0 &&
6029	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6030	+	addToPendingCount(1);
6031	+	(rights = new MapReduceEntriesToLongTask<K,V>
6032	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6033	+	rights, transformer, r, reducer)).fork();
6034	+	}
6035	+	for (Node<K,V> p; (p = advance()) != null; )
6036	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6037	+	result = r;
6038	+	CountedCompleter<?> c;
6039	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6040	+	@SuppressWarnings("unchecked")
6041	+	MapReduceEntriesToLongTask<K,V>
6042	+	t = (MapReduceEntriesToLongTask<K,V>)c,
6043	+	s = t.rights;
6044	+	while (s != null) {
6045	+	t.result = reducer.applyAsLong(t.result, s.result);
6046	+	s = t.rights = s.nextRight;
6047	+	}
6048	+	}
6049	+	}
6050	+	}
6051	+	}
6052	+
6053	+	@SuppressWarnings("serial")
6054	+	static final class MapReduceMappingsToLongTask<K,V>
6055	+	extends BulkTask<K,V,Long> {
6056	+	final ToLongBiFunction<? super K, ? super V> transformer;
6057	+	final LongBinaryOperator reducer;
6058	+	final long basis;
6059	+	long result;
6060	+	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6061	+	MapReduceMappingsToLongTask
6062	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6063	+	MapReduceMappingsToLongTask<K,V> nextRight,
6064	+	ToLongBiFunction<? super K, ? super V> transformer,
6065	+	long basis,
6066	+	LongBinaryOperator reducer) {
6067	+	super(p, b, i, f, t); this.nextRight = nextRight;
6068	+	this.transformer = transformer;
6069	+	this.basis = basis; this.reducer = reducer;
6070	+	}
6071	+	public final Long getRawResult() { return result; }
6072	+	public final void compute() {
6073	+	final ToLongBiFunction<? super K, ? super V> transformer;
6074	+	final LongBinaryOperator reducer;
6075	+	if ((transformer = this.transformer) != null &&
6076	+	(reducer = this.reducer) != null) {
6077	+	long r = this.basis;
6078	+	for (int i = baseIndex, f, h; batch > 0 &&
6079	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6080	+	addToPendingCount(1);
6081	+	(rights = new MapReduceMappingsToLongTask<K,V>
6082	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6083	+	rights, transformer, r, reducer)).fork();
6084	+	}
6085	+	for (Node<K,V> p; (p = advance()) != null; )
6086	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6087	+	result = r;
6088	+	CountedCompleter<?> c;
6089	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6090	+	@SuppressWarnings("unchecked")
6091	+	MapReduceMappingsToLongTask<K,V>
6092	+	t = (MapReduceMappingsToLongTask<K,V>)c,
6093	+	s = t.rights;
6094	+	while (s != null) {
6095	+	t.result = reducer.applyAsLong(t.result, s.result);
6096	+	s = t.rights = s.nextRight;
6097	+	}
6098	+	}
6099	+	}
6100	+	}
6101	+	}
6102	+
6103	+	@SuppressWarnings("serial")
6104	+	static final class MapReduceKeysToIntTask<K,V>
6105	+	extends BulkTask<K,V,Integer> {
6106	+	final ToIntFunction<? super K> transformer;
6107	+	final IntBinaryOperator reducer;
6108	+	final int basis;
6109	+	int result;
6110	+	MapReduceKeysToIntTask<K,V> rights, nextRight;
6111	+	MapReduceKeysToIntTask
6112	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6113	+	MapReduceKeysToIntTask<K,V> nextRight,
6114	+	ToIntFunction<? super K> transformer,
6115	+	int basis,
6116	+	IntBinaryOperator reducer) {
6117	+	super(p, b, i, f, t); this.nextRight = nextRight;
6118	+	this.transformer = transformer;
6119	+	this.basis = basis; this.reducer = reducer;
6120	+	}
6121	+	public final Integer getRawResult() { return result; }
6122	+	public final void compute() {
6123	+	final ToIntFunction<? super K> transformer;
6124	+	final IntBinaryOperator reducer;
6125	+	if ((transformer = this.transformer) != null &&
6126	+	(reducer = this.reducer) != null) {
6127	+	int r = this.basis;
6128	+	for (int i = baseIndex, f, h; batch > 0 &&
6129	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6130	+	addToPendingCount(1);
6131	+	(rights = new MapReduceKeysToIntTask<K,V>
6132	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6133	+	rights, transformer, r, reducer)).fork();
6134	+	}
6135	+	for (Node<K,V> p; (p = advance()) != null; )
6136	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6137	+	result = r;
6138	+	CountedCompleter<?> c;
6139	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6140	+	@SuppressWarnings("unchecked")
6141	+	MapReduceKeysToIntTask<K,V>
6142	+	t = (MapReduceKeysToIntTask<K,V>)c,
6143	+	s = t.rights;
6144	+	while (s != null) {
6145	+	t.result = reducer.applyAsInt(t.result, s.result);
6146	+	s = t.rights = s.nextRight;
6147	+	}
6148	+	}
6149	+	}
6150	+	}
6151	+	}
6152	+
6153	+	@SuppressWarnings("serial")
6154	+	static final class MapReduceValuesToIntTask<K,V>
6155	+	extends BulkTask<K,V,Integer> {
6156	+	final ToIntFunction<? super V> transformer;
6157	+	final IntBinaryOperator reducer;
6158	+	final int basis;
6159	+	int result;
6160	+	MapReduceValuesToIntTask<K,V> rights, nextRight;
6161	+	MapReduceValuesToIntTask
6162	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6163	+	MapReduceValuesToIntTask<K,V> nextRight,
6164	+	ToIntFunction<? super V> transformer,
6165	+	int basis,
6166	+	IntBinaryOperator reducer) {
6167	+	super(p, b, i, f, t); this.nextRight = nextRight;
6168	+	this.transformer = transformer;
6169	+	this.basis = basis; this.reducer = reducer;
6170	+	}
6171	+	public final Integer getRawResult() { return result; }
6172	+	public final void compute() {
6173	+	final ToIntFunction<? super V> transformer;
6174	+	final IntBinaryOperator reducer;
6175	+	if ((transformer = this.transformer) != null &&
6176	+	(reducer = this.reducer) != null) {
6177	+	int r = this.basis;
6178	+	for (int i = baseIndex, f, h; batch > 0 &&
6179	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6180	+	addToPendingCount(1);
6181	+	(rights = new MapReduceValuesToIntTask<K,V>
6182	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6183	+	rights, transformer, r, reducer)).fork();
6184	+	}
6185	+	for (Node<K,V> p; (p = advance()) != null; )
6186	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6187	+	result = r;
6188	+	CountedCompleter<?> c;
6189	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6190	+	@SuppressWarnings("unchecked")
6191	+	MapReduceValuesToIntTask<K,V>
6192	+	t = (MapReduceValuesToIntTask<K,V>)c,
6193	+	s = t.rights;
6194	+	while (s != null) {
6195	+	t.result = reducer.applyAsInt(t.result, s.result);
6196	+	s = t.rights = s.nextRight;
6197	+	}
6198	+	}
6199	+	}
6200	+	}
6201	+	}
6202	+
6203	+	@SuppressWarnings("serial")
6204	+	static final class MapReduceEntriesToIntTask<K,V>
6205	+	extends BulkTask<K,V,Integer> {
6206	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6207	+	final IntBinaryOperator reducer;
6208	+	final int basis;
6209	+	int result;
6210	+	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6211	+	MapReduceEntriesToIntTask
6212	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6213	+	MapReduceEntriesToIntTask<K,V> nextRight,
6214	+	ToIntFunction<Map.Entry<K,V>> transformer,
6215	+	int basis,
6216	+	IntBinaryOperator reducer) {
6217	+	super(p, b, i, f, t); this.nextRight = nextRight;
6218	+	this.transformer = transformer;
6219	+	this.basis = basis; this.reducer = reducer;
6220	+	}
6221	+	public final Integer getRawResult() { return result; }
6222	+	public final void compute() {
6223	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6224	+	final IntBinaryOperator reducer;
6225	+	if ((transformer = this.transformer) != null &&
6226	+	(reducer = this.reducer) != null) {
6227	+	int r = this.basis;
6228	+	for (int i = baseIndex, f, h; batch > 0 &&
6229	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6230	+	addToPendingCount(1);
6231	+	(rights = new MapReduceEntriesToIntTask<K,V>
6232	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6233	+	rights, transformer, r, reducer)).fork();
6234	+	}
6235	+	for (Node<K,V> p; (p = advance()) != null; )
6236	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6237	+	result = r;
6238	+	CountedCompleter<?> c;
6239	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6240	+	@SuppressWarnings("unchecked")
6241	+	MapReduceEntriesToIntTask<K,V>
6242	+	t = (MapReduceEntriesToIntTask<K,V>)c,
6243	+	s = t.rights;
6244	+	while (s != null) {
6245	+	t.result = reducer.applyAsInt(t.result, s.result);
6246	+	s = t.rights = s.nextRight;
6247	+	}
6248	+	}
6249	+	}
6250	+	}
6251	+	}
6252	+
6253	+	@SuppressWarnings("serial")
6254	+	static final class MapReduceMappingsToIntTask<K,V>
6255	+	extends BulkTask<K,V,Integer> {
6256	+	final ToIntBiFunction<? super K, ? super V> transformer;
6257	+	final IntBinaryOperator reducer;
6258	+	final int basis;
6259	+	int result;
6260	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6261	+	MapReduceMappingsToIntTask
6262	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6263	+	MapReduceMappingsToIntTask<K,V> nextRight,
6264	+	ToIntBiFunction<? super K, ? super V> transformer,
6265	+	int basis,
6266	+	IntBinaryOperator reducer) {
6267	+	super(p, b, i, f, t); this.nextRight = nextRight;
6268	+	this.transformer = transformer;
6269	+	this.basis = basis; this.reducer = reducer;
6270	+	}
6271	+	public final Integer getRawResult() { return result; }
6272	+	public final void compute() {
6273	+	final ToIntBiFunction<? super K, ? super V> transformer;
6274	+	final IntBinaryOperator reducer;
6275	+	if ((transformer = this.transformer) != null &&
6276	+	(reducer = this.reducer) != null) {
6277	+	int r = this.basis;
6278	+	for (int i = baseIndex, f, h; batch > 0 &&
6279	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6280	+	addToPendingCount(1);
6281	+	(rights = new MapReduceMappingsToIntTask<K,V>
6282	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6283	+	rights, transformer, r, reducer)).fork();
6284	+	}
6285	+	for (Node<K,V> p; (p = advance()) != null; )
6286	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6287	+	result = r;
6288	+	CountedCompleter<?> c;
6289	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6290	+	@SuppressWarnings("unchecked")
6291	+	MapReduceMappingsToIntTask<K,V>
6292	+	t = (MapReduceMappingsToIntTask<K,V>)c,
6293	+	s = t.rights;
6294	+	while (s != null) {
6295	+	t.result = reducer.applyAsInt(t.result, s.result);
6296	+	s = t.rights = s.nextRight;
6297	+	}
6298	+	}
6299	+	}
6300	+	}
6301	+	}
6302	+
6303	+	// Unsafe mechanics
6304	+	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
6305	+	private static final long SIZECTL;
6306	+	private static final long TRANSFERINDEX;
6307	+	private static final long BASECOUNT;
6308	+	private static final long CELLSBUSY;
6309	+	private static final long CELLVALUE;
6310	+	private static final int ABASE;
6311	+	private static final int ASHIFT;
6312	+
6313	+	static {
6314	+	try {
6315	+	SIZECTL = U.objectFieldOffset
6316	+	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6317	+	TRANSFERINDEX = U.objectFieldOffset
6318	+	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6319	+	BASECOUNT = U.objectFieldOffset
6320	+	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6321	+	CELLSBUSY = U.objectFieldOffset
6322	+	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6323	+
6324	+	CELLVALUE = U.objectFieldOffset
6325	+	(CounterCell.class.getDeclaredField("value"));
6326	+
6327	+	ABASE = U.arrayBaseOffset(Node[].class);
6328	+	int scale = U.arrayIndexScale(Node[].class);
6329	+	if ((scale & (scale - 1)) != 0)
6330	+	throw new Error("array index scale not a power of two");
6331	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6332	+	} catch (ReflectiveOperationException e) {
6333	+	throw new Error(e);
6334	+	}
6335	+
6336	+	// Reduce the risk of rare disastrous classloading in first call to
6337	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6338	+	Class<?> ensureLoaded = LockSupport.class;
6339	+	}
6340	+	}

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