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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.64 by jsr166, Mon May 2 18:38:53 2005 UTC vs.
Revision 1.238 by jsr166, Thu Jul 18 18:21:22 2013 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, as explained at
4	<	* http://creativecommons.org/licenses/publicdomain
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.Comparator;
17	>	import java.util.ConcurrentModificationException;
18	>	import java.util.Enumeration;
19	>	import java.util.HashMap;
20	>	import java.util.Hashtable;
21	>	import java.util.Iterator;
22	>	import java.util.Map;
23	>	import java.util.NoSuchElementException;
24	>	import java.util.Set;
25	>	import java.util.Spliterator;
26	>	import java.util.concurrent.ConcurrentMap;
27	>	import java.util.concurrent.ForkJoinPool;
28	>	import java.util.concurrent.atomic.AtomicReference;
29	>	import java.util.concurrent.locks.LockSupport;
30	>	import java.util.concurrent.locks.ReentrantLock;
31	>	import java.util.function.BiConsumer;
32	>	import java.util.function.BiFunction;
33	>	import java.util.function.BinaryOperator;
34	>	import java.util.function.Consumer;
35	>	import java.util.function.DoubleBinaryOperator;
36	>	import java.util.function.Function;
37	>	import java.util.function.IntBinaryOperator;
38	>	import java.util.function.LongBinaryOperator;
39	>	import java.util.function.ToDoubleBiFunction;
40	>	import java.util.function.ToDoubleFunction;
41	>	import java.util.function.ToIntBiFunction;
42	>	import java.util.function.ToIntFunction;
43	>	import java.util.function.ToLongBiFunction;
44	>	import java.util.function.ToLongFunction;
45	>	import java.util.stream.Stream;
46
47		/**
48		* A hash table supporting full concurrency of retrievals and
49	<	* adjustable expected concurrency for updates. This class obeys the
49	>	* high expected concurrency for updates. This class obeys the
50		* same functional specification as {@link java.util.Hashtable}, and
51		* includes versions of methods corresponding to each method of
52	<	* <tt>Hashtable</tt>. However, even though all operations are
52	>	* {@code Hashtable}. However, even though all operations are
53		* thread-safe, retrieval operations do <em>not</em> entail locking,
54		* and there is <em>not</em> any support for locking the entire table
55		* in a way that prevents all access.  This class is fully
56	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
56	>	* interoperable with {@code Hashtable} in programs that rely on its
57		* thread safety but not on its synchronization details.
58		*
59	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
60	<	* block, so may overlap with update operations (including
61	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
62	<	* of the most recently <em>completed</em> update operations holding
63	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
64	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
65	<	* removal of only some entries.  Similarly, Iterators and
66	<	* Enumerations return elements reflecting the state of the hash table
67	<	* at some point at or since the creation of the iterator/enumeration.
68	<	* They do <em>not</em> throw
69	<	* {@link ConcurrentModificationException}.  However, iterators are
70	<	* designed to be used by only one thread at a time.
71	<	*
72	<	* <p> The allowed concurrency among update operations is guided by
73	<	* the optional <tt>concurrencyLevel</tt> constructor argument
74	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
75	<	* table is internally partitioned to try to permit the indicated
76	<	* number of concurrent updates without contention. Because placement
77	<	* in hash tables is essentially random, the actual concurrency will
78	<	* vary.  Ideally, you should choose a value to accommodate as many
79	<	* threads as will ever concurrently modify the table. Using a
80	<	* significantly higher value than you need can waste space and time,
81	<	* and a significantly lower value can lead to thread contention. But
82	<	* overestimates and underestimates within an order of magnitude do
83	<	* not usually have much noticeable impact. A value of one is
84	<	* appropriate when it is known that only one thread will modify and
85	<	* all others will only read. Also, resizing this or any other kind of
86	<	* hash table is a relatively slow operation, so, when possible, it is
87	<	* a good idea to provide estimates of expected table sizes in
88	<	* constructors.
59	>	* <p>Retrieval operations (including {@code get}) generally do not
60	>	* block, so may overlap with update operations (including {@code put}
61	>	* and {@code remove}). Retrievals reflect the results of the most
62	>	* recently <em>completed</em> update operations holding upon their
63	>	* onset. (More formally, an update operation for a given key bears a
64	>	* <em>happens-before</em> relation with any (non-null) retrieval for
65	>	* that key reporting the updated value.)  For aggregate operations
66	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
67	>	* reflect insertion or removal of only some entries.  Similarly,
68	>	* Iterators and Enumerations return elements reflecting the state of
69	>	* the hash table at some point at or since the creation of the
70	>	* iterator/enumeration.  They do <em>not</em> throw {@link
71	>	* ConcurrentModificationException}.  However, iterators are designed
72	>	* to be used by only one thread at a time.  Bear in mind that the
73	>	* results of aggregate status methods including {@code size}, {@code
74	>	* isEmpty}, and {@code containsValue} are typically useful only when
75	>	* a map is not undergoing concurrent updates in other threads.
76	>	* Otherwise the results of these methods reflect transient states
77	>	* that may be adequate for monitoring or estimation purposes, but not
78	>	* for program control.
79	>	*
80	>	* <p>The table is dynamically expanded when there are too many
81	>	* collisions (i.e., keys that have distinct hash codes but fall into
82	>	* the same slot modulo the table size), with the expected average
83	>	* effect of maintaining roughly two bins per mapping (corresponding
84	>	* to a 0.75 load factor threshold for resizing). There may be much
85	>	* variance around this average as mappings are added and removed, but
86	>	* overall, this maintains a commonly accepted time/space tradeoff for
87	>	* hash tables.  However, resizing this or any other kind of hash
88	>	* table may be a relatively slow operation. When possible, it is a
89	>	* good idea to provide a size estimate as an optional {@code
90	>	* initialCapacity} constructor argument. An additional optional
91	>	* {@code loadFactor} constructor argument provides a further means of
92	>	* customizing initial table capacity by specifying the table density
93	>	* to be used in calculating the amount of space to allocate for the
94	>	* given number of elements.  Also, for compatibility with previous
95	>	* versions of this class, constructors may optionally specify an
96	>	* expected {@code concurrencyLevel} as an additional hint for
97	>	* internal sizing.  Note that using many keys with exactly the same
98	>	* {@code hashCode()} is a sure way to slow down performance of any
99	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
100	>	* this class may use comparison order among keys to help break ties.
101	>	*
102	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
103	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
104	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
105	>	* mapped values are (perhaps transiently) not used or all take the
106	>	* same mapping value.
107	>	*
108	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
109	>	* form of histogram or multiset) by using {@link
110	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
111	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
112	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
113	>	* {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();}
114		*
115		* <p>This class and its views and iterators implement all of the
116		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
117		* interfaces.
118		*
119	<	* <p> Like {@link java.util.Hashtable} but unlike {@link
120	<	* java.util.HashMap}, this class does NOT allow <tt>null</tt> to be
121	<	* used as a key or value.
119	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
120	>	* does <em>not</em> allow {@code null} to be used as a key or value.
121	>	*
122	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
123	>	* operations that, unlike most {@link Stream} methods, are designed
124	>	* to be safely, and often sensibly, applied even with maps that are
125	>	* being concurrently updated by other threads; for example, when
126	>	* computing a snapshot summary of the values in a shared registry.
127	>	* There are three kinds of operation, each with four forms, accepting
128	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
129	>	* and/or return values. Because the elements of a ConcurrentHashMap
130	>	* are not ordered in any particular way, and may be processed in
131	>	* different orders in different parallel executions, the correctness
132	>	* of supplied functions should not depend on any ordering, or on any
133	>	* other objects or values that may transiently change while
134	>	* computation is in progress; and except for forEach actions, should
135	>	* ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry}
136	>	* objects do not support method {@code setValue}.
137	>	*
138	>	* <ul>
139	>	* <li> forEach: Perform a given action on each element.
140	>	* A variant form applies a given transformation on each element
141	>	* before performing the action.</li>
142	>	*
143	>	* <li> search: Return the first available non-null result of
144	>	* applying a given function on each element; skipping further
145	>	* search when a result is found.</li>
146	>	*
147	>	* <li> reduce: Accumulate each element.  The supplied reduction
148	>	* function cannot rely on ordering (more formally, it should be
149	>	* both associative and commutative).  There are five variants:
150	>	*
151	>	* <ul>
152	>	*
153	>	* <li> Plain reductions. (There is not a form of this method for
154	>	* (key, value) function arguments since there is no corresponding
155	>	* return type.)</li>
156	>	*
157	>	* <li> Mapped reductions that accumulate the results of a given
158	>	* function applied to each element.</li>
159	>	*
160	>	* <li> Reductions to scalar doubles, longs, and ints, using a
161	>	* given basis value.</li>
162	>	*
163	>	* </ul>
164	>	* </li>
165	>	* </ul>
166	>	*
167	>	* <p>These bulk operations accept a {@code parallelismThreshold}
168	>	* argument. Methods proceed sequentially if the current map size is
169	>	* estimated to be less than the given threshold. Using a value of
170	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
171	>	* of {@code 1} results in maximal parallelism by partitioning into
172	>	* enough subtasks to fully utilize the {@link
173	>	* ForkJoinPool#commonPool()} that is used for all parallel
174	>	* computations. Normally, you would initially choose one of these
175	>	* extreme values, and then measure performance of using in-between
176	>	* values that trade off overhead versus throughput.
177	>	*
178	>	* <p>The concurrency properties of bulk operations follow
179	>	* from those of ConcurrentHashMap: Any non-null result returned
180	>	* from {@code get(key)} and related access methods bears a
181	>	* happens-before relation with the associated insertion or
182	>	* update.  The result of any bulk operation reflects the
183	>	* composition of these per-element relations (but is not
184	>	* necessarily atomic with respect to the map as a whole unless it
185	>	* is somehow known to be quiescent).  Conversely, because keys
186	>	* and values in the map are never null, null serves as a reliable
187	>	* atomic indicator of the current lack of any result.  To
188	>	* maintain this property, null serves as an implicit basis for
189	>	* all non-scalar reduction operations. For the double, long, and
190	>	* int versions, the basis should be one that, when combined with
191	>	* any other value, returns that other value (more formally, it
192	>	* should be the identity element for the reduction). Most common
193	>	* reductions have these properties; for example, computing a sum
194	>	* with basis 0 or a minimum with basis MAX_VALUE.
195	>	*
196	>	* <p>Search and transformation functions provided as arguments
197	>	* should similarly return null to indicate the lack of any result
198	>	* (in which case it is not used). In the case of mapped
199	>	* reductions, this also enables transformations to serve as
200	>	* filters, returning null (or, in the case of primitive
201	>	* specializations, the identity basis) if the element should not
202	>	* be combined. You can create compound transformations and
203	>	* filterings by composing them yourself under this "null means
204	>	* there is nothing there now" rule before using them in search or
205	>	* reduce operations.
206	>	*
207	>	* <p>Methods accepting and/or returning Entry arguments maintain
208	>	* key-value associations. They may be useful for example when
209	>	* finding the key for the greatest value. Note that "plain" Entry
210	>	* arguments can be supplied using {@code new
211	>	* AbstractMap.SimpleEntry(k,v)}.
212	>	*
213	>	* <p>Bulk operations may complete abruptly, throwing an
214	>	* exception encountered in the application of a supplied
215	>	* function. Bear in mind when handling such exceptions that other
216	>	* concurrently executing functions could also have thrown
217	>	* exceptions, or would have done so if the first exception had
218	>	* not occurred.
219	>	*
220	>	* <p>Speedups for parallel compared to sequential forms are common
221	>	* but not guaranteed.  Parallel operations involving brief functions
222	>	* on small maps may execute more slowly than sequential forms if the
223	>	* underlying work to parallelize the computation is more expensive
224	>	* than the computation itself.  Similarly, parallelization may not
225	>	* lead to much actual parallelism if all processors are busy
226	>	* performing unrelated tasks.
227	>	*
228	>	* <p>All arguments to all task methods must be non-null.
229		*
230		* <p>This class is a member of the
231	<	* <a href="{@docRoot}/../guide/collections/index.html">
231	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
232		* Java Collections Framework</a>.
233		*
234		* @since 1.5
#	Line 72 | Line 236 | import java.io.ObjectOutputStream;
236		* @param <K> the type of keys maintained by this map
237		* @param <V> the type of mapped values
238		*/
239	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
76	<	implements ConcurrentMap<K, V>, Serializable {
239	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V> implements ConcurrentMap<K,V>, Serializable {
240		private static final long serialVersionUID = 7249069246763182397L;
241
242		/*
243	<	* The basic strategy is to subdivide the table among Segments,
244	<	* each of which itself is a concurrently readable hash table.
243	>	* Overview:
244	>	*
245	>	* The primary design goal of this hash table is to maintain
246	>	* concurrent readability (typically method get(), but also
247	>	* iterators and related methods) while minimizing update
248	>	* contention. Secondary goals are to keep space consumption about
249	>	* the same or better than java.util.HashMap, and to support high
250	>	* initial insertion rates on an empty table by many threads.
251	>	*
252	>	* This map usually acts as a binned (bucketed) hash table.  Each
253	>	* key-value mapping is held in a Node.  Most nodes are instances
254	>	* of the basic Node class with hash, key, value, and next
255	>	* fields. However, various subclasses exist: TreeNodes are
256	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
257	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
258	>	* of bins during resizing. ReservationNodes are used as
259	>	* placeholders while establishing values in computeIfAbsent and
260	>	* related methods.  The types TreeBin, ForwardingNode, and
261	>	* ReservationNode do not hold normal user keys, values, or
262	>	* hashes, and are readily distinguishable during search etc
263	>	* because they have negative hash fields and null key and value
264	>	* fields. (These special nodes are either uncommon or transient,
265	>	* so the impact of carrying around some unused fields is
266	>	* insignificant.)
267	>	*
268	>	* The table is lazily initialized to a power-of-two size upon the
269	>	* first insertion.  Each bin in the table normally contains a
270	>	* list of Nodes (most often, the list has only zero or one Node).
271	>	* Table accesses require volatile/atomic reads, writes, and
272	>	* CASes.  Because there is no other way to arrange this without
273	>	* adding further indirections, we use intrinsics
274	>	* (sun.misc.Unsafe) operations.
275	>	*
276	>	* We use the top (sign) bit of Node hash fields for control
277	>	* purposes -- it is available anyway because of addressing
278	>	* constraints.  Nodes with negative hash fields are specially
279	>	* handled or ignored in map methods.
280	>	*
281	>	* Insertion (via put or its variants) of the first node in an
282	>	* empty bin is performed by just CASing it to the bin.  This is
283	>	* by far the most common case for put operations under most
284	>	* key/hash distributions.  Other update operations (insert,
285	>	* delete, and replace) require locks.  We do not want to waste
286	>	* the space required to associate a distinct lock object with
287	>	* each bin, so instead use the first node of a bin list itself as
288	>	* a lock. Locking support for these locks relies on builtin
289	>	* "synchronized" monitors.
290	>	*
291	>	* Using the first node of a list as a lock does not by itself
292	>	* suffice though: When a node is locked, any update must first
293	>	* validate that it is still the first node after locking it, and
294	>	* retry if not. Because new nodes are always appended to lists,
295	>	* once a node is first in a bin, it remains first until deleted
296	>	* or the bin becomes invalidated (upon resizing).
297	>	*
298	>	* The main disadvantage of per-bin locks is that other update
299	>	* operations on other nodes in a bin list protected by the same
300	>	* lock can stall, for example when user equals() or mapping
301	>	* functions take a long time.  However, statistically, under
302	>	* random hash codes, this is not a common problem.  Ideally, the
303	>	* frequency of nodes in bins follows a Poisson distribution
304	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
305	>	* parameter of about 0.5 on average, given the resizing threshold
306	>	* of 0.75, although with a large variance because of resizing
307	>	* granularity. Ignoring variance, the expected occurrences of
308	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
309	>	* first values are:
310	>	*
311	>	* 0:    0.60653066
312	>	* 1:    0.30326533
313	>	* 2:    0.07581633
314	>	* 3:    0.01263606
315	>	* 4:    0.00157952
316	>	* 5:    0.00015795
317	>	* 6:    0.00001316
318	>	* 7:    0.00000094
319	>	* 8:    0.00000006
320	>	* more: less than 1 in ten million
321	>	*
322	>	* Lock contention probability for two threads accessing distinct
323	>	* elements is roughly 1 / (8 * #elements) under random hashes.
324	>	*
325	>	* Actual hash code distributions encountered in practice
326	>	* sometimes deviate significantly from uniform randomness.  This
327	>	* includes the case when N > (1<<30), so some keys MUST collide.
328	>	* Similarly for dumb or hostile usages in which multiple keys are
329	>	* designed to have identical hash codes or ones that differs only
330	>	* in masked-out high bits. So we use a secondary strategy that
331	>	* applies when the number of nodes in a bin exceeds a
332	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
333	>	* specialized form of red-black trees), bounding search time to
334	>	* O(log N).  Each search step in a TreeBin is at least twice as
335	>	* slow as in a regular list, but given that N cannot exceed
336	>	* (1<<64) (before running out of addresses) this bounds search
337	>	* steps, lock hold times, etc, to reasonable constants (roughly
338	>	* 100 nodes inspected per operation worst case) so long as keys
339	>	* are Comparable (which is very common -- String, Long, etc).
340	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
341	>	* traversal pointers as regular nodes, so can be traversed in
342	>	* iterators in the same way.
343	>	*
344	>	* The table is resized when occupancy exceeds a percentage
345	>	* threshold (nominally, 0.75, but see below).  Any thread
346	>	* noticing an overfull bin may assist in resizing after the
347	>	* initiating thread allocates and sets up the replacement
348	>	* array. However, rather than stalling, these other threads may
349	>	* proceed with insertions etc.  The use of TreeBins shields us
350	>	* from the worst case effects of overfilling while resizes are in
351	>	* progress.  Resizing proceeds by transferring bins, one by one,
352	>	* from the table to the next table. To enable concurrency, the
353	>	* next table must be (incrementally) prefilled with place-holders
354	>	* serving as reverse forwarders to the old table.  Because we are
355	>	* using power-of-two expansion, the elements from each bin must
356	>	* either stay at same index, or move with a power of two
357	>	* offset. We eliminate unnecessary node creation by catching
358	>	* cases where old nodes can be reused because their next fields
359	>	* won't change.  On average, only about one-sixth of them need
360	>	* cloning when a table doubles. The nodes they replace will be
361	>	* garbage collectable as soon as they are no longer referenced by
362	>	* any reader thread that may be in the midst of concurrently
363	>	* traversing table.  Upon transfer, the old table bin contains
364	>	* only a special forwarding node (with hash field "MOVED") that
365	>	* contains the next table as its key. On encountering a
366	>	* forwarding node, access and update operations restart, using
367	>	* the new table.
368	>	*
369	>	* Each bin transfer requires its bin lock, which can stall
370	>	* waiting for locks while resizing. However, because other
371	>	* threads can join in and help resize rather than contend for
372	>	* locks, average aggregate waits become shorter as resizing
373	>	* progresses.  The transfer operation must also ensure that all
374	>	* accessible bins in both the old and new table are usable by any
375	>	* traversal.  This is arranged by proceeding from the last bin
376	>	* (table.length - 1) up towards the first.  Upon seeing a
377	>	* forwarding node, traversals (see class Traverser) arrange to
378	>	* move to the new table without revisiting nodes.  However, to
379	>	* ensure that no intervening nodes are skipped, bin splitting can
380	>	* only begin after the associated reverse-forwarders are in
381	>	* place.
382	>	*
383	>	* The traversal scheme also applies to partial traversals of
384	>	* ranges of bins (via an alternate Traverser constructor)
385	>	* to support partitioned aggregate operations.  Also, read-only
386	>	* operations give up if ever forwarded to a null table, which
387	>	* provides support for shutdown-style clearing, which is also not
388	>	* currently implemented.
389	>	*
390	>	* Lazy table initialization minimizes footprint until first use,
391	>	* and also avoids resizings when the first operation is from a
392	>	* putAll, constructor with map argument, or deserialization.
393	>	* These cases attempt to override the initial capacity settings,
394	>	* but harmlessly fail to take effect in cases of races.
395	>	*
396	>	* The element count is maintained using a specialization of
397	>	* LongAdder. We need to incorporate a specialization rather than
398	>	* just use a LongAdder in order to access implicit
399	>	* contention-sensing that leads to creation of multiple
400	>	* CounterCells.  The counter mechanics avoid contention on
401	>	* updates but can encounter cache thrashing if read too
402	>	* frequently during concurrent access. To avoid reading so often,
403	>	* resizing under contention is attempted only upon adding to a
404	>	* bin already holding two or more nodes. Under uniform hash
405	>	* distributions, the probability of this occurring at threshold
406	>	* is around 13%, meaning that only about 1 in 8 puts check
407	>	* threshold (and after resizing, many fewer do so).
408	>	*
409	>	* TreeBins use a special form of comparison for search and
410	>	* related operations (which is the main reason we cannot use
411	>	* existing collections such as TreeMaps). TreeBins contain
412	>	* Comparable elements, but may contain others, as well as
413	>	* elements that are Comparable but not necessarily Comparable
414	>	* for the same T, so we cannot invoke compareTo among them. To
415	>	* handle this, the tree is ordered primarily by hash value, then
416	>	* by Comparable.compareTo order if applicable.  On lookup at a
417	>	* node, if elements are not comparable or compare as 0 then both
418	>	* left and right children may need to be searched in the case of
419	>	* tied hash values. (This corresponds to the full list search
420	>	* that would be necessary if all elements were non-Comparable and
421	>	* had tied hashes.)  The red-black balancing code is updated from
422	>	* pre-jdk-collections
423	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
424	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
425	>	* Algorithms" (CLR).
426	>	*
427	>	* TreeBins also require an additional locking mechanism.  While
428	>	* list traversal is always possible by readers even during
429	>	* updates, tree traversal is not, mainly because of tree-rotations
430	>	* that may change the root node and/or its linkages.  TreeBins
431	>	* include a simple read-write lock mechanism parasitic on the
432	>	* main bin-synchronization strategy: Structural adjustments
433	>	* associated with an insertion or removal are already bin-locked
434	>	* (and so cannot conflict with other writers) but must wait for
435	>	* ongoing readers to finish. Since there can be only one such
436	>	* waiter, we use a simple scheme using a single "waiter" field to
437	>	* block writers.  However, readers need never block.  If the root
438	>	* lock is held, they proceed along the slow traversal path (via
439	>	* next-pointers) until the lock becomes available or the list is
440	>	* exhausted, whichever comes first. These cases are not fast, but
441	>	* maximize aggregate expected throughput.
442	>	*
443	>	* Maintaining API and serialization compatibility with previous
444	>	* versions of this class introduces several oddities. Mainly: We
445	>	* leave untouched but unused constructor arguments refering to
446	>	* concurrencyLevel. We accept a loadFactor constructor argument,
447	>	* but apply it only to initial table capacity (which is the only
448	>	* time that we can guarantee to honor it.) We also declare an
449	>	* unused "Segment" class that is instantiated in minimal form
450	>	* only when serializing.
451	>	*
452	>	* This file is organized to make things a little easier to follow
453	>	* while reading than they might otherwise: First the main static
454	>	* declarations and utilities, then fields, then main public
455	>	* methods (with a few factorings of multiple public methods into
456	>	* internal ones), then sizing methods, trees, traversers, and
457	>	* bulk operations.
458		*/
459
460		/* ---------------- Constants -------------- */
461
462		/**
463	<	* The default initial capacity for this table,
464	<	* used when not otherwise specified in a constructor.
463	>	* The largest possible table capacity.  This value must be
464	>	* exactly 1<<30 to stay within Java array allocation and indexing
465	>	* bounds for power of two table sizes, and is further required
466	>	* because the top two bits of 32bit hash fields are used for
467	>	* control purposes.
468		*/
469	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
469	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
470
471		/**
472	<	* The default load factor for this table, used when not
473	<	* otherwise specified in a constructor.
472	>	* The default initial table capacity.  Must be a power of 2
473	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
474		*/
475	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
475	>	private static final int DEFAULT_CAPACITY = 16;
476
477		/**
478	<	* The default concurrency level for this table, used when not
479	<	* otherwise specified in a constructor.
478	>	* The largest possible (non-power of two) array size.
479	>	* Needed by toArray and related methods.
480		*/
481	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
481	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
482
483		/**
484	<	* The maximum capacity, used if a higher value is implicitly
485	<	* specified by either of the constructors with arguments.  MUST
107	<	* be a power of two <= 1<<30 to ensure that entries are indexible
108	<	* using ints.
484	>	* The default concurrency level for this table. Unused but
485	>	* defined for compatibility with previous versions of this class.
486		*/
487	<	static final int MAXIMUM_CAPACITY = 1 << 30;
487	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
488
489		/**
490	<	* The maximum number of segments to allow; used to bound
491	<	* constructor arguments.
490	>	* The load factor for this table. Overrides of this value in
491	>	* constructors affect only the initial table capacity.  The
492	>	* actual floating point value isn't normally used -- it is
493	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
494	>	* the associated resizing threshold.
495		*/
496	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
496	>	private static final float LOAD_FACTOR = 0.75f;
497
498		/**
499	<	* Number of unsynchronized retries in size and containsValue
500	<	* methods before resorting to locking. This is used to avoid
501	<	* unbounded retries if tables undergo continuous modification
502	<	* which would make it impossible to obtain an accurate result.
499	>	* The bin count threshold for using a tree rather than list for a
500	>	* bin.  Bins are converted to trees when adding an element to a
501	>	* bin with at least this many nodes. The value must be greater
502	>	* than 2, and should be at least 8 to mesh with assumptions in
503	>	* tree removal about conversion back to plain bins upon
504	>	* shrinkage.
505		*/
506	<	static final int RETRIES_BEFORE_LOCK = 2;
506	>	static final int TREEIFY_THRESHOLD = 8;
507
508	<	/* ---------------- Fields -------------- */
508	>	/**
509	>	* The bin count threshold for untreeifying a (split) bin during a
510	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
511	>	* most 6 to mesh with shrinkage detection under removal.
512	>	*/
513	>	static final int UNTREEIFY_THRESHOLD = 6;
514
515		/**
516	<	* Mask value for indexing into segments. The upper bits of a
517	<	* key's hash code are used to choose the segment.
516	>	* The smallest table capacity for which bins may be treeified.
517	>	* (Otherwise the table is resized if too many nodes in a bin.)
518	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
519	>	* conflicts between resizing and treeification thresholds.
520		*/
521	<	final int segmentMask;
521	>	static final int MIN_TREEIFY_CAPACITY = 64;
522
523		/**
524	<	* Shift value for indexing within segments.
524	>	* Minimum number of rebinnings per transfer step. Ranges are
525	>	* subdivided to allow multiple resizer threads.  This value
526	>	* serves as a lower bound to avoid resizers encountering
527	>	* excessive memory contention.  The value should be at least
528	>	* DEFAULT_CAPACITY.
529		*/
530	<	final int segmentShift;
530	>	private static final int MIN_TRANSFER_STRIDE = 16;
531	>
532	>	/*
533	>	* Encodings for Node hash fields. See above for explanation.
534	>	*/
535	>	static final int MOVED     = -1; // hash for forwarding nodes
536	>	static final int TREEBIN   = -2; // hash for roots of trees
537	>	static final int RESERVED  = -3; // hash for transient reservations
538	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
539	>
540	>	/** Number of CPUS, to place bounds on some sizings */
541	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
542	>
543	>	/** For serialization compatibility. */
544	>	private static final ObjectStreamField[] serialPersistentFields = {
545	>	new ObjectStreamField("segments", Segment[].class),
546	>	new ObjectStreamField("segmentMask", Integer.TYPE),
547	>	new ObjectStreamField("segmentShift", Integer.TYPE)
548	>	};
549	>
550	>	/* ---------------- Nodes -------------- */
551
552		/**
553	<	* The segments, each of which is a specialized hash table
553	>	* Key-value entry.  This class is never exported out as a
554	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
555	>	* MapEntry below), but can be used for read-only traversals used
556	>	* in bulk tasks.  Subclasses of Node with a negative hash field
557	>	* are special, and contain null keys and values (but are never
558	>	* exported).  Otherwise, keys and vals are never null.
559		*/
560	<	final Segment[] segments;
560	>	static class Node<K,V> implements Map.Entry<K,V> {
561	>	final int hash;
562	>	final K key;
563	>	volatile V val;
564	>	volatile Node<K,V> next;
565	>
566	>	Node(int hash, K key, V val, Node<K,V> next) {
567	>	this.hash = hash;
568	>	this.key = key;
569	>	this.val = val;
570	>	this.next = next;
571	>	}
572
573	<	transient Set<K> keySet;
574	<	transient Set<Map.Entry<K,V>> entrySet;
575	<	transient Collection<V> values;
573	>	public final K getKey()       { return key; }
574	>	public final V getValue()     { return val; }
575	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
576	>	public final String toString(){ return key + "=" + val; }
577	>	public final V setValue(V value) {
578	>	throw new UnsupportedOperationException();
579	>	}
580	>
581	>	public final boolean equals(Object o) {
582	>	Object k, v, u; Map.Entry<?,?> e;
583	>	return ((o instanceof Map.Entry) &&
584	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
585	>	(v = e.getValue()) != null &&
586	>	(k == key || k.equals(key)) &&
587	>	(v == (u = val) || v.equals(u)));
588	>	}
589	>
590	>	/**
591	>	* Virtualized support for map.get(); overridden in subclasses.
592	>	*/
593	>	Node<K,V> find(int h, Object k) {
594	>	Node<K,V> e = this;
595	>	if (k != null) {
596	>	do {
597	>	K ek;
598	>	if (e.hash == h &&
599	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
600	>	return e;
601	>	} while ((e = e.next) != null);
602	>	}
603	>	return null;
604	>	}
605	>	}
606
607	<	/* ---------------- Small Utilities -------------- */
607	>	/* ---------------- Static utilities -------------- */
608
609		/**
610	<	* Returns a hash code for non-null Object x.
611	<	* Uses the same hash code spreader as most other java.util hash tables.
612	<	* @param x the object serving as a key
613	<	* @return the hash code
610	>	* Spreads (XORs) higher bits of hash to lower and also forces top
611	>	* bit to 0. Because the table uses power-of-two masking, sets of
612	>	* hashes that vary only in bits above the current mask will
613	>	* always collide. (Among known examples are sets of Float keys
614	>	* holding consecutive whole numbers in small tables.)  So we
615	>	* apply a transform that spreads the impact of higher bits
616	>	* downward. There is a tradeoff between speed, utility, and
617	>	* quality of bit-spreading. Because many common sets of hashes
618	>	* are already reasonably distributed (so don't benefit from
619	>	* spreading), and because we use trees to handle large sets of
620	>	* collisions in bins, we just XOR some shifted bits in the
621	>	* cheapest possible way to reduce systematic lossage, as well as
622	>	* to incorporate impact of the highest bits that would otherwise
623	>	* never be used in index calculations because of table bounds.
624		*/
625	<	static int hash(Object x) {
626	<	int h = x.hashCode();
158	<	h += ~(h << 9);
159	<	h ^=  (h >>> 14);
160	<	h +=  (h << 4);
161	<	h ^=  (h >>> 10);
162	<	return h;
625	>	static final int spread(int h) {
626	>	return (h ^ (h >>> 16)) & HASH_BITS;
627		}
628
629		/**
630	<	* Returns the segment that should be used for key with given hash
631	<	* @param hash the hash code for the key
168	<	* @return the segment
630	>	* Returns a power of two table size for the given desired capacity.
631	>	* See Hackers Delight, sec 3.2
632		*/
633	<	final Segment<K,V> segmentFor(int hash) {
634	<	return (Segment<K,V>) segments[(hash >>> segmentShift) & segmentMask];
633	>	private static final int tableSizeFor(int c) {
634	>	int n = c - 1;
635	>	n |= n >>> 1;
636	>	n |= n >>> 2;
637	>	n |= n >>> 4;
638	>	n |= n >>> 8;
639	>	n |= n >>> 16;
640	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
641		}
642
643	<	/* ---------------- Inner Classes -------------- */
643	>	/**
644	>	* Returns x's Class if it is of the form "class C implements
645	>	* Comparable<C>", else null.
646	>	*/
647	>	static Class<?> comparableClassFor(Object x) {
648	>	if (x instanceof Comparable) {
649	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
650	>	if ((c = x.getClass()) == String.class) // bypass checks
651	>	return c;
652	>	if ((ts = c.getGenericInterfaces()) != null) {
653	>	for (int i = 0; i < ts.length; ++i) {
654	>	if (((t = ts[i]) instanceof ParameterizedType) &&
655	>	((p = (ParameterizedType)t).getRawType() ==
656	>	Comparable.class) &&
657	>	(as = p.getActualTypeArguments()) != null &&
658	>	as.length == 1 && as[0] == c) // type arg is c
659	>	return c;
660	>	}
661	>	}
662	>	}
663	>	return null;
664	>	}
665
666		/**
667	<	* ConcurrentHashMap list entry. Note that this is never exported
668	<	* out as a user-visible Map.Entry.
179	<	*
180	<	* Because the value field is volatile, not final, it is legal wrt
181	<	* the Java Memory Model for an unsynchronized reader to see null
182	<	* instead of initial value when read via a data race.  Although a
183	<	* reordering leading to this is not likely to ever actually
184	<	* occur, the Segment.readValueUnderLock method is used as a
185	<	* backup in case a null (pre-initialized) value is ever seen in
186	<	* an unsynchronized access method.
667	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
668	>	* class), else 0.
669		*/
670	<	static final class HashEntry<K,V> {
671	<	final K key;
672	<	final int hash;
673	<	volatile V value;
674	<	final HashEntry<K,V> next;
670	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
671	>	static int compareComparables(Class<?> kc, Object k, Object x) {
672	>	return (x == null || x.getClass() != kc ? 0 :
673	>	((Comparable)k).compareTo(x));
674	>	}
675
676	<	HashEntry(K key, int hash, HashEntry<K,V> next, V value) {
677	<	this.key = key;
678	<	this.hash = hash;
679	<	this.next = next;
680	<	this.value = value;
681	<	}
676	>	/* ---------------- Table element access -------------- */
677	>
678	>	/*
679	>	* Volatile access methods are used for table elements as well as
680	>	* elements of in-progress next table while resizing.  All uses of
681	>	* the tab arguments must be null checked by callers.  All callers
682	>	* also paranoically precheck that tab's length is not zero (or an
683	>	* equivalent check), thus ensuring that any index argument taking
684	>	* the form of a hash value anded with (length - 1) is a valid
685	>	* index.  Note that, to be correct wrt arbitrary concurrency
686	>	* errors by users, these checks must operate on local variables,
687	>	* which accounts for some odd-looking inline assignments below.
688	>	* Note that calls to setTabAt always occur within locked regions,
689	>	* and so in principle require only release ordering, not need
690	>	* full volatile semantics, but are currently coded as volatile
691	>	* writes to be conservative.
692	>	*/
693	>
694	>	@SuppressWarnings("unchecked")
695	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
696	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
697		}
698
699	+	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
700	+	Node<K,V> c, Node<K,V> v) {
701	+	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
702	+	}
703	+
704	+	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
705	+	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
706	+	}
707	+
708	+	/* ---------------- Fields -------------- */
709	+
710		/**
711	<	* Segments are specialized versions of hash tables.  This
712	<	* subclasses from ReentrantLock opportunistically, just to
205	<	* simplify some locking and avoid separate construction.
711	>	* The array of bins. Lazily initialized upon first insertion.
712	>	* Size is always a power of two. Accessed directly by iterators.
713		*/
714	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
208	<	/*
209	<	* Segments maintain a table of entry lists that are ALWAYS
210	<	* kept in a consistent state, so can be read without locking.
211	<	* Next fields of nodes are immutable (final).  All list
212	<	* additions are performed at the front of each bin. This
213	<	* makes it easy to check changes, and also fast to traverse.
214	<	* When nodes would otherwise be changed, new nodes are
215	<	* created to replace them. This works well for hash tables
216	<	* since the bin lists tend to be short. (The average length
217	<	* is less than two for the default load factor threshold.)
218	<	*
219	<	* Read operations can thus proceed without locking, but rely
220	<	* on selected uses of volatiles to ensure that completed
221	<	* write operations performed by other threads are
222	<	* noticed. For most purposes, the "count" field, tracking the
223	<	* number of elements, serves as that volatile variable
224	<	* ensuring visibility.  This is convenient because this field
225	<	* needs to be read in many read operations anyway:
226	<	*
227	<	*   - All (unsynchronized) read operations must first read the
228	<	*     "count" field, and should not look at table entries if
229	<	*     it is 0.
230	<	*
231	<	*   - All (synchronized) write operations should write to
232	<	*     the "count" field after structurally changing any bin.
233	<	*     The operations must not take any action that could even
234	<	*     momentarily cause a concurrent read operation to see
235	<	*     inconsistent data. This is made easier by the nature of
236	<	*     the read operations in Map. For example, no operation
237	<	*     can reveal that the table has grown but the threshold
238	<	*     has not yet been updated, so there are no atomicity
239	<	*     requirements for this with respect to reads.
240	<	*
241	<	* As a guide, all critical volatile reads and writes to the
242	<	* count field are marked in code comments.
243	<	*/
714	>	transient volatile Node<K,V>[] table;
715
716	<	private static final long serialVersionUID = 2249069246763182397L;
716	>	/**
717	>	* The next table to use; non-null only while resizing.
718	>	*/
719	>	private transient volatile Node<K,V>[] nextTable;
720
721	<	/**
722	<	* The number of elements in this segment's region.
723	<	*/
724	<	transient volatile int count;
721	>	/**
722	>	* Base counter value, used mainly when there is no contention,
723	>	* but also as a fallback during table initialization
724	>	* races. Updated via CAS.
725	>	*/
726	>	private transient volatile long baseCount;
727
728	<	/**
729	<	* Number of updates that alter the size of the table. This is
730	<	* used during bulk-read methods to make sure they see a
731	<	* consistent snapshot: If modCounts change during a traversal
732	<	* of segments computing size or checking containsValue, then
733	<	* we might have an inconsistent view of state so (usually)
734	<	* must retry.
735	<	*/
736	<	transient int modCount;
728	>	/**
729	>	* Table initialization and resizing control.  When negative, the
730	>	* table is being initialized or resized: -1 for initialization,
731	>	* else -(1 + the number of active resizing threads).  Otherwise,
732	>	* when table is null, holds the initial table size to use upon
733	>	* creation, or 0 for default. After initialization, holds the
734	>	* next element count value upon which to resize the table.
735	>	*/
736	>	private transient volatile int sizeCtl;
737
738	<	/**
739	<	* The table is rehashed when its size exceeds this threshold.
740	<	* (The value of this field is always (int)(capacity *
741	<	* loadFactor).)
266	<	*/
267	<	transient int threshold;
738	>	/**
739	>	* The next table index (plus one) to split while resizing.
740	>	*/
741	>	private transient volatile int transferIndex;
742
743	<	/**
744	<	* The per-segment table. Declared as a raw type, casted
745	<	* to HashEntry<K,V> on each use.
746	<	*/
273	<	transient volatile HashEntry[] table;
743	>	/**
744	>	* The least available table index to split while resizing.
745	>	*/
746	>	private transient volatile int transferOrigin;
747
748	<	/**
749	<	* The load factor for the hash table.  Even though this value
750	<	* is same for all segments, it is replicated to avoid needing
751	<	* links to outer object.
279	<	* @serial
280	<	*/
281	<	final float loadFactor;
748	>	/**
749	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
750	>	*/
751	>	private transient volatile int cellsBusy;
752
753	<	Segment(int initialCapacity, float lf) {
754	<	loadFactor = lf;
755	<	setTable(new HashEntry[initialCapacity]);
756	<	}
753	>	/**
754	>	* Table of counter cells. When non-null, size is a power of 2.
755	>	*/
756	>	private transient volatile CounterCell[] counterCells;
757
758	<	/**
759	<	* Sets table to new HashEntry array.
760	<	* Call only while holding lock or in constructor.
761	<	*/
292	<	void setTable(HashEntry[] newTable) {
293	<	threshold = (int)(newTable.length * loadFactor);
294	<	table = newTable;
295	<	}
758	>	// views
759	>	private transient KeySetView<K,V> keySet;
760	>	private transient ValuesView<K,V> values;
761	>	private transient EntrySetView<K,V> entrySet;
762
763	<	/**
764	<	* Returns properly casted first entry of bin for given hash.
765	<	*/
766	<	HashEntry<K,V> getFirst(int hash) {
767	<	HashEntry[] tab = table;
768	<	return (HashEntry<K,V>) tab[hash & (tab.length - 1)];
763	>
764	>	/* ---------------- Public operations -------------- */
765	>
766	>	/**
767	>	* Creates a new, empty map with the default initial table size (16).
768	>	*/
769	>	public ConcurrentHashMap() {
770	>	}
771	>
772	>	/**
773	>	* Creates a new, empty map with an initial table size
774	>	* accommodating the specified number of elements without the need
775	>	* to dynamically resize.
776	>	*
777	>	* @param initialCapacity The implementation performs internal
778	>	* sizing to accommodate this many elements.
779	>	* @throws IllegalArgumentException if the initial capacity of
780	>	* elements is negative
781	>	*/
782	>	public ConcurrentHashMap(int initialCapacity) {
783	>	if (initialCapacity < 0)
784	>	throw new IllegalArgumentException();
785	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
786	>	MAXIMUM_CAPACITY :
787	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
788	>	this.sizeCtl = cap;
789	>	}
790	>
791	>	/**
792	>	* Creates a new map with the same mappings as the given map.
793	>	*
794	>	* @param m the map
795	>	*/
796	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
797	>	this.sizeCtl = DEFAULT_CAPACITY;
798	>	putAll(m);
799	>	}
800	>
801	>	/**
802	>	* Creates a new, empty map with an initial table size based on
803	>	* the given number of elements ({@code initialCapacity}) and
804	>	* initial table density ({@code loadFactor}).
805	>	*
806	>	* @param initialCapacity the initial capacity. The implementation
807	>	* performs internal sizing to accommodate this many elements,
808	>	* given the specified load factor.
809	>	* @param loadFactor the load factor (table density) for
810	>	* establishing the initial table size
811	>	* @throws IllegalArgumentException if the initial capacity of
812	>	* elements is negative or the load factor is nonpositive
813	>	*
814	>	* @since 1.6
815	>	*/
816	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
817	>	this(initialCapacity, loadFactor, 1);
818	>	}
819	>
820	>	/**
821	>	* Creates a new, empty map with an initial table size based on
822	>	* the given number of elements ({@code initialCapacity}), table
823	>	* density ({@code loadFactor}), and number of concurrently
824	>	* updating threads ({@code concurrencyLevel}).
825	>	*
826	>	* @param initialCapacity the initial capacity. The implementation
827	>	* performs internal sizing to accommodate this many elements,
828	>	* given the specified load factor.
829	>	* @param loadFactor the load factor (table density) for
830	>	* establishing the initial table size
831	>	* @param concurrencyLevel the estimated number of concurrently
832	>	* updating threads. The implementation may use this value as
833	>	* a sizing hint.
834	>	* @throws IllegalArgumentException if the initial capacity is
835	>	* negative or the load factor or concurrencyLevel are
836	>	* nonpositive
837	>	*/
838	>	public ConcurrentHashMap(int initialCapacity,
839	>	float loadFactor, int concurrencyLevel) {
840	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
841	>	throw new IllegalArgumentException();
842	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
843	>	initialCapacity = concurrencyLevel;   // as estimated threads
844	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
845	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
846	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
847	>	this.sizeCtl = cap;
848	>	}
849	>
850	>	// Original (since JDK1.2) Map methods
851	>
852	>	/**
853	>	* {@inheritDoc}
854	>	*/
855	>	public int size() {
856	>	long n = sumCount();
857	>	return ((n < 0L) ? 0 :
858	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
859	>	(int)n);
860	>	}
861	>
862	>	/**
863	>	* {@inheritDoc}
864	>	*/
865	>	public boolean isEmpty() {
866	>	return sumCount() <= 0L; // ignore transient negative values
867	>	}
868	>
869	>	/**
870	>	* Returns the value to which the specified key is mapped,
871	>	* or {@code null} if this map contains no mapping for the key.
872	>	*
873	>	* <p>More formally, if this map contains a mapping from a key
874	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
875	>	* then this method returns {@code v}; otherwise it returns
876	>	* {@code null}.  (There can be at most one such mapping.)
877	>	*
878	>	* @throws NullPointerException if the specified key is null
879	>	*/
880	>	public V get(Object key) {
881	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
882	>	int h = spread(key.hashCode());
883	>	if ((tab = table) != null && (n = tab.length) > 0 &&
884	>	(e = tabAt(tab, (n - 1) & h)) != null) {
885	>	if ((eh = e.hash) == h) {
886	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
887	>	return e.val;
888	>	}
889	>	else if (eh < 0)
890	>	return (p = e.find(h, key)) != null ? p.val : null;
891	>	while ((e = e.next) != null) {
892	>	if (e.hash == h &&
893	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
894	>	return e.val;
895	>	}
896		}
897	+	return null;
898	+	}
899
900	<	/**
901	<	* Reads value field of an entry under lock. Called if value
902	<	* field ever appears to be null. This is possible only if a
903	<	* compiler happens to reorder a HashEntry initialization with
904	<	* its table assignment, which is legal under memory model
905	<	* but is not known to ever occur.
906	<	*/
907	<	V readValueUnderLock(HashEntry<K,V> e) {
908	<	lock();
909	<	try {
910	<	return e.value;
911	<	} finally {
912	<	unlock();
900	>	/**
901	>	* Tests if the specified object is a key in this table.
902	>	*
903	>	* @param  key possible key
904	>	* @return {@code true} if and only if the specified object
905	>	*         is a key in this table, as determined by the
906	>	*         {@code equals} method; {@code false} otherwise
907	>	* @throws NullPointerException if the specified key is null
908	>	*/
909	>	public boolean containsKey(Object key) {
910	>	return get(key) != null;
911	>	}
912	>
913	>	/**
914	>	* Returns {@code true} if this map maps one or more keys to the
915	>	* specified value. Note: This method may require a full traversal
916	>	* of the map, and is much slower than method {@code containsKey}.
917	>	*
918	>	* @param value value whose presence in this map is to be tested
919	>	* @return {@code true} if this map maps one or more keys to the
920	>	*         specified value
921	>	* @throws NullPointerException if the specified value is null
922	>	*/
923	>	public boolean containsValue(Object value) {
924	>	if (value == null)
925	>	throw new NullPointerException();
926	>	Node<K,V>[] t;
927	>	if ((t = table) != null) {
928	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
929	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
930	>	V v;
931	>	if ((v = p.val) == value || (v != null && value.equals(v)))
932	>	return true;
933		}
934		}
935	+	return false;
936	+	}
937
938	<	/* Specialized implementations of map methods */
938	>	/**
939	>	* Maps the specified key to the specified value in this table.
940	>	* Neither the key nor the value can be null.
941	>	*
942	>	* <p>The value can be retrieved by calling the {@code get} method
943	>	* with a key that is equal to the original key.
944	>	*
945	>	* @param key key with which the specified value is to be associated
946	>	* @param value value to be associated with the specified key
947	>	* @return the previous value associated with {@code key}, or
948	>	*         {@code null} if there was no mapping for {@code key}
949	>	* @throws NullPointerException if the specified key or value is null
950	>	*/
951	>	public V put(K key, V value) {
952	>	return putVal(key, value, false);
953	>	}
954
955	<	V get(Object key, int hash) {
956	<	if (count != 0) { // read-volatile
957	<	HashEntry<K,V> e = getFirst(hash);
958	<	while (e != null) {
959	<	if (e.hash == hash && key.equals(e.key)) {
960	<	V v = e.value;
961	<	if (v != null)
962	<	return v;
963	<	return readValueUnderLock(e); // recheck
955	>	/** Implementation for put and putIfAbsent */
956	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
957	>	if (key == null || value == null) throw new NullPointerException();
958	>	int hash = spread(key.hashCode());
959	>	int binCount = 0;
960	>	for (Node<K,V>[] tab = table;;) {
961	>	Node<K,V> f; int n, i, fh;
962	>	if (tab == null || (n = tab.length) == 0)
963	>	tab = initTable();
964	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
965	>	if (casTabAt(tab, i, null,
966	>	new Node<K,V>(hash, key, value, null)))
967	>	break;                   // no lock when adding to empty bin
968	>	}
969	>	else if ((fh = f.hash) == MOVED)
970	>	tab = helpTransfer(tab, f);
971	>	else {
972	>	V oldVal = null;
973	>	synchronized (f) {
974	>	if (tabAt(tab, i) == f) {
975	>	if (fh >= 0) {
976	>	binCount = 1;
977	>	for (Node<K,V> e = f;; ++binCount) {
978	>	K ek;
979	>	if (e.hash == hash &&
980	>	((ek = e.key) == key ||
981	>	(ek != null && key.equals(ek)))) {
982	>	oldVal = e.val;
983	>	if (!onlyIfAbsent)
984	>	e.val = value;
985	>	break;
986	>	}
987	>	Node<K,V> pred = e;
988	>	if ((e = e.next) == null) {
989	>	pred.next = new Node<K,V>(hash, key,
990	>	value, null);
991	>	break;
992	>	}
993	>	}
994	>	}
995	>	else if (f instanceof TreeBin) {
996	>	Node<K,V> p;
997	>	binCount = 2;
998	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
999	>	value)) != null) {
1000	>	oldVal = p.val;
1001	>	if (!onlyIfAbsent)
1002	>	p.val = value;
1003	>	}
1004	>	}
1005		}
1006	<	e = e.next;
1006	>	}
1007	>	if (binCount != 0) {
1008	>	if (binCount >= TREEIFY_THRESHOLD)
1009	>	treeifyBin(tab, i);
1010	>	if (oldVal != null)
1011	>	return oldVal;
1012	>	break;
1013		}
1014		}
336	–	return null;
1015		}
1016	+	addCount(1L, binCount);
1017	+	return null;
1018	+	}
1019
1020	<	boolean containsKey(Object key, int hash) {
1021	<	if (count != 0) { // read-volatile
1022	<	HashEntry<K,V> e = getFirst(hash);
1023	<	while (e != null) {
1024	<	if (e.hash == hash && key.equals(e.key))
1025	<	return true;
1026	<	e = e.next;
1020	>	/**
1021	>	* Copies all of the mappings from the specified map to this one.
1022	>	* These mappings replace any mappings that this map had for any of the
1023	>	* keys currently in the specified map.
1024	>	*
1025	>	* @param m mappings to be stored in this map
1026	>	*/
1027	>	public void putAll(Map<? extends K, ? extends V> m) {
1028	>	tryPresize(m.size());
1029	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1030	>	putVal(e.getKey(), e.getValue(), false);
1031	>	}
1032	>
1033	>	/**
1034	>	* Removes the key (and its corresponding value) from this map.
1035	>	* This method does nothing if the key is not in the map.
1036	>	*
1037	>	* @param  key the key that needs to be removed
1038	>	* @return the previous value associated with {@code key}, or
1039	>	*         {@code null} if there was no mapping for {@code key}
1040	>	* @throws NullPointerException if the specified key is null
1041	>	*/
1042	>	public V remove(Object key) {
1043	>	return replaceNode(key, null, null);
1044	>	}
1045	>
1046	>	/**
1047	>	* Implementation for the four public remove/replace methods:
1048	>	* Replaces node value with v, conditional upon match of cv if
1049	>	* non-null.  If resulting value is null, delete.
1050	>	*/
1051	>	final V replaceNode(Object key, V value, Object cv) {
1052	>	int hash = spread(key.hashCode());
1053	>	for (Node<K,V>[] tab = table;;) {
1054	>	Node<K,V> f; int n, i, fh;
1055	>	if (tab == null || (n = tab.length) == 0 ||
1056	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1057	>	break;
1058	>	else if ((fh = f.hash) == MOVED)
1059	>	tab = helpTransfer(tab, f);
1060	>	else {
1061	>	V oldVal = null;
1062	>	boolean validated = false;
1063	>	synchronized (f) {
1064	>	if (tabAt(tab, i) == f) {
1065	>	if (fh >= 0) {
1066	>	validated = true;
1067	>	for (Node<K,V> e = f, pred = null;;) {
1068	>	K ek;
1069	>	if (e.hash == hash &&
1070	>	((ek = e.key) == key ||
1071	>	(ek != null && key.equals(ek)))) {
1072	>	V ev = e.val;
1073	>	if (cv == null || cv == ev ||
1074	>	(ev != null && cv.equals(ev))) {
1075	>	oldVal = ev;
1076	>	if (value != null)
1077	>	e.val = value;
1078	>	else if (pred != null)
1079	>	pred.next = e.next;
1080	>	else
1081	>	setTabAt(tab, i, e.next);
1082	>	}
1083	>	break;
1084	>	}
1085	>	pred = e;
1086	>	if ((e = e.next) == null)
1087	>	break;
1088	>	}
1089	>	}
1090	>	else if (f instanceof TreeBin) {
1091	>	validated = true;
1092	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1093	>	TreeNode<K,V> r, p;
1094	>	if ((r = t.root) != null &&
1095	>	(p = r.findTreeNode(hash, key, null)) != null) {
1096	>	V pv = p.val;
1097	>	if (cv == null || cv == pv ||
1098	>	(pv != null && cv.equals(pv))) {
1099	>	oldVal = pv;
1100	>	if (value != null)
1101	>	p.val = value;
1102	>	else if (t.removeTreeNode(p))
1103	>	setTabAt(tab, i, untreeify(t.first));
1104	>	}
1105	>	}
1106	>	}
1107	>	}
1108	>	}
1109	>	if (validated) {
1110	>	if (oldVal != null) {
1111	>	if (value == null)
1112	>	addCount(-1L, -1);
1113	>	return oldVal;
1114	>	}
1115	>	break;
1116		}
1117		}
348	–	return false;
1118		}
1119	+	return null;
1120	+	}
1121
1122	<	boolean containsValue(Object value) {
1123	<	if (count != 0) { // read-volatile
1124	<	HashEntry[] tab = table;
1125	<	int len = tab.length;
1126	<	for (int i = 0 ; i < len; i++) {
1127	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i];
1128	<	e != null ;
1129	<	e = e.next) {
1130	<	V v = e.value;
1131	<	if (v == null) // recheck
1132	<	v = readValueUnderLock(e);
1133	<	if (value.equals(v))
1134	<	return true;
1122	>	/**
1123	>	* Removes all of the mappings from this map.
1124	>	*/
1125	>	public void clear() {
1126	>	long delta = 0L; // negative number of deletions
1127	>	int i = 0;
1128	>	Node<K,V>[] tab = table;
1129	>	while (tab != null && i < tab.length) {
1130	>	int fh;
1131	>	Node<K,V> f = tabAt(tab, i);
1132	>	if (f == null)
1133	>	++i;
1134	>	else if ((fh = f.hash) == MOVED) {
1135	>	tab = helpTransfer(tab, f);
1136	>	i = 0; // restart
1137	>	}
1138	>	else {
1139	>	synchronized (f) {
1140	>	if (tabAt(tab, i) == f) {
1141	>	Node<K,V> p = (fh >= 0 ? f :
1142	>	(f instanceof TreeBin) ?
1143	>	((TreeBin<K,V>)f).first : null);
1144	>	while (p != null) {
1145	>	--delta;
1146	>	p = p.next;
1147	>	}
1148	>	setTabAt(tab, i++, null);
1149		}
1150		}
1151		}
367	–	return false;
1152		}
1153	+	if (delta != 0L)
1154	+	addCount(delta, -1);
1155	+	}
1156
1157	<	boolean replace(K key, int hash, V oldValue, V newValue) {
1158	<	lock();
1159	<	try {
1160	<	HashEntry<K,V> e = getFirst(hash);
1161	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
1162	<	e = e.next;
1163	<
1164	<	boolean replaced = false;
1165	<	if (e != null && oldValue.equals(e.value)) {
1166	<	replaced = true;
1167	<	e.value = newValue;
1168	<	}
1169	<	return replaced;
1170	<	} finally {
1171	<	unlock();
1157	>	/**
1158	>	* Returns a {@link Set} view of the keys contained in this map.
1159	>	* The set is backed by the map, so changes to the map are
1160	>	* reflected in the set, and vice-versa. The set supports element
1161	>	* removal, which removes the corresponding mapping from this map,
1162	>	* via the {@code Iterator.remove}, {@code Set.remove},
1163	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1164	>	* operations.  It does not support the {@code add} or
1165	>	* {@code addAll} operations.
1166	>	*
1167	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
1168	>	* that will never throw {@link ConcurrentModificationException},
1169	>	* and guarantees to traverse elements as they existed upon
1170	>	* construction of the iterator, and may (but is not guaranteed to)
1171	>	* reflect any modifications subsequent to construction.
1172	>	*
1173	>	* @return the set view
1174	>	*/
1175	>	public KeySetView<K,V> keySet() {
1176	>	KeySetView<K,V> ks;
1177	>	return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1178	>	}
1179	>
1180	>	/**
1181	>	* Returns a {@link Collection} view of the values contained in this map.
1182	>	* The collection is backed by the map, so changes to the map are
1183	>	* reflected in the collection, and vice-versa.  The collection
1184	>	* supports element removal, which removes the corresponding
1185	>	* mapping from this map, via the {@code Iterator.remove},
1186	>	* {@code Collection.remove}, {@code removeAll},
1187	>	* {@code retainAll}, and {@code clear} operations.  It does not
1188	>	* support the {@code add} or {@code addAll} operations.
1189	>	*
1190	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
1191	>	* that will never throw {@link ConcurrentModificationException},
1192	>	* and guarantees to traverse elements as they existed upon
1193	>	* construction of the iterator, and may (but is not guaranteed to)
1194	>	* reflect any modifications subsequent to construction.
1195	>	*
1196	>	* @return the collection view
1197	>	*/
1198	>	public Collection<V> values() {
1199	>	ValuesView<K,V> vs;
1200	>	return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1201	>	}
1202	>
1203	>	/**
1204	>	* Returns a {@link Set} view of the mappings contained in this map.
1205	>	* The set is backed by the map, so changes to the map are
1206	>	* reflected in the set, and vice-versa.  The set supports element
1207	>	* removal, which removes the corresponding mapping from the map,
1208	>	* via the {@code Iterator.remove}, {@code Set.remove},
1209	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1210	>	* operations.
1211	>	*
1212	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
1213	>	* that will never throw {@link ConcurrentModificationException},
1214	>	* and guarantees to traverse elements as they existed upon
1215	>	* construction of the iterator, and may (but is not guaranteed to)
1216	>	* reflect any modifications subsequent to construction.
1217	>	*
1218	>	* @return the set view
1219	>	*/
1220	>	public Set<Map.Entry<K,V>> entrySet() {
1221	>	EntrySetView<K,V> es;
1222	>	return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1223	>	}
1224	>
1225	>	/**
1226	>	* Returns the hash code value for this {@link Map}, i.e.,
1227	>	* the sum of, for each key-value pair in the map,
1228	>	* {@code key.hashCode() ^ value.hashCode()}.
1229	>	*
1230	>	* @return the hash code value for this map
1231	>	*/
1232	>	public int hashCode() {
1233	>	int h = 0;
1234	>	Node<K,V>[] t;
1235	>	if ((t = table) != null) {
1236	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1237	>	for (Node<K,V> p; (p = it.advance()) != null; )
1238	>	h += p.key.hashCode() ^ p.val.hashCode();
1239	>	}
1240	>	return h;
1241	>	}
1242	>
1243	>	/**
1244	>	* Returns a string representation of this map.  The string
1245	>	* representation consists of a list of key-value mappings (in no
1246	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1247	>	* mappings are separated by the characters {@code ", "} (comma
1248	>	* and space).  Each key-value mapping is rendered as the key
1249	>	* followed by an equals sign ("{@code =}") followed by the
1250	>	* associated value.
1251	>	*
1252	>	* @return a string representation of this map
1253	>	*/
1254	>	public String toString() {
1255	>	Node<K,V>[] t;
1256	>	int f = (t = table) == null ? 0 : t.length;
1257	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1258	>	StringBuilder sb = new StringBuilder();
1259	>	sb.append('{');
1260	>	Node<K,V> p;
1261	>	if ((p = it.advance()) != null) {
1262	>	for (;;) {
1263	>	K k = p.key;
1264	>	V v = p.val;
1265	>	sb.append(k == this ? "(this Map)" : k);
1266	>	sb.append('=');
1267	>	sb.append(v == this ? "(this Map)" : v);
1268	>	if ((p = it.advance()) == null)
1269	>	break;
1270	>	sb.append(',').append(' ');
1271		}
1272		}
1273	+	return sb.append('}').toString();
1274	+	}
1275
1276	<	V replace(K key, int hash, V newValue) {
1277	<	lock();
1278	<	try {
1279	<	HashEntry<K,V> e = getFirst(hash);
1280	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
1281	<	e = e.next;
1282	<
1283	<	V oldValue = null;
1284	<	if (e != null) {
1285	<	oldValue = e.value;
1286	<	e.value = newValue;
1287	<	}
1288	<	return oldValue;
1289	<	} finally {
1290	<	unlock();
1276	>	/**
1277	>	* Compares the specified object with this map for equality.
1278	>	* Returns {@code true} if the given object is a map with the same
1279	>	* mappings as this map.  This operation may return misleading
1280	>	* results if either map is concurrently modified during execution
1281	>	* of this method.
1282	>	*
1283	>	* @param o object to be compared for equality with this map
1284	>	* @return {@code true} if the specified object is equal to this map
1285	>	*/
1286	>	public boolean equals(Object o) {
1287	>	if (o != this) {
1288	>	if (!(o instanceof Map))
1289	>	return false;
1290	>	Map<?,?> m = (Map<?,?>) o;
1291	>	Node<K,V>[] t;
1292	>	int f = (t = table) == null ? 0 : t.length;
1293	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1294	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1295	>	V val = p.val;
1296	>	Object v = m.get(p.key);
1297	>	if (v == null || (v != val && !v.equals(val)))
1298	>	return false;
1299	>	}
1300	>	for (Map.Entry<?,?> e : m.entrySet()) {
1301	>	Object mk, mv, v;
1302	>	if ((mk = e.getKey()) == null ||
1303	>	(mv = e.getValue()) == null ||
1304	>	(v = get(mk)) == null ||
1305	>	(mv != v && !mv.equals(v)))
1306	>	return false;
1307		}
1308		}
1309	+	return true;
1310	+	}
1311
1312	+	/**
1313	+	* Stripped-down version of helper class used in previous version,
1314	+	* declared for the sake of serialization compatibility
1315	+	*/
1316	+	static class Segment<K,V> extends ReentrantLock implements Serializable {
1317	+	private static final long serialVersionUID = 2249069246763182397L;
1318	+	final float loadFactor;
1319	+	Segment(float lf) { this.loadFactor = lf; }
1320	+	}
1321
1322	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
1323	<	lock();
1324	<	try {
1325	<	int c = count;
1326	<	if (c++ > threshold) // ensure capacity
1327	<	rehash();
1328	<	HashEntry[] tab = table;
1329	<	int index = hash & (tab.length - 1);
1330	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1331	<	HashEntry<K,V> e = first;
1332	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
1333	<	e = e.next;
1334	<
1335	<	V oldValue;
1336	<	if (e != null) {
1337	<	oldValue = e.value;
1338	<	if (!onlyIfAbsent)
1339	<	e.value = value;
1340	<	}
1322	>	/**
1323	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1324	>	* stream (i.e., serializes it).
1325	>	* @param s the stream
1326	>	* @throws java.io.IOException if an I/O error occurs
1327	>	* @serialData
1328	>	* the key (Object) and value (Object)
1329	>	* for each key-value mapping, followed by a null pair.
1330	>	* The key-value mappings are emitted in no particular order.
1331	>	*/
1332	>	private void writeObject(java.io.ObjectOutputStream s)
1333	>	throws java.io.IOException {
1334	>	// For serialization compatibility
1335	>	// Emulate segment calculation from previous version of this class
1336	>	int sshift = 0;
1337	>	int ssize = 1;
1338	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1339	>	++sshift;
1340	>	ssize <<= 1;
1341	>	}
1342	>	int segmentShift = 32 - sshift;
1343	>	int segmentMask = ssize - 1;
1344	>	@SuppressWarnings("unchecked") Segment<K,V>[] segments = (Segment<K,V>[])
1345	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1346	>	for (int i = 0; i < segments.length; ++i)
1347	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1348	>	s.putFields().put("segments", segments);
1349	>	s.putFields().put("segmentShift", segmentShift);
1350	>	s.putFields().put("segmentMask", segmentMask);
1351	>	s.writeFields();
1352	>
1353	>	Node<K,V>[] t;
1354	>	if ((t = table) != null) {
1355	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1356	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1357	>	s.writeObject(p.key);
1358	>	s.writeObject(p.val);
1359	>	}
1360	>	}
1361	>	s.writeObject(null);
1362	>	s.writeObject(null);
1363	>	segments = null; // throw away
1364	>	}
1365	>
1366	>	/**
1367	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1368	>	* @param s the stream
1369	>	* @throws ClassNotFoundException if the class of a serialized object
1370	>	*         could not be found
1371	>	* @throws java.io.IOException if an I/O error occurs
1372	>	*/
1373	>	private void readObject(java.io.ObjectInputStream s)
1374	>	throws java.io.IOException, ClassNotFoundException {
1375	>	/*
1376	>	* To improve performance in typical cases, we create nodes
1377	>	* while reading, then place in table once size is known.
1378	>	* However, we must also validate uniqueness and deal with
1379	>	* overpopulated bins while doing so, which requires
1380	>	* specialized versions of putVal mechanics.
1381	>	*/
1382	>	sizeCtl = -1; // force exclusion for table construction
1383	>	s.defaultReadObject();
1384	>	long size = 0L;
1385	>	Node<K,V> p = null;
1386	>	for (;;) {
1387	>	@SuppressWarnings("unchecked") K k = (K) s.readObject();
1388	>	@SuppressWarnings("unchecked") V v = (V) s.readObject();
1389	>	if (k != null && v != null) {
1390	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1391	>	++size;
1392	>	}
1393	>	else
1394	>	break;
1395	>	}
1396	>	if (size == 0L)
1397	>	sizeCtl = 0;
1398	>	else {
1399	>	int n;
1400	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1401	>	n = MAXIMUM_CAPACITY;
1402	>	else {
1403	>	int sz = (int)size;
1404	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1405	>	}
1406	>	@SuppressWarnings({"rawtypes","unchecked"})
1407	>	Node<K,V>[] tab = (Node<K,V>[])new Node[n];
1408	>	int mask = n - 1;
1409	>	long added = 0L;
1410	>	while (p != null) {
1411	>	boolean insertAtFront;
1412	>	Node<K,V> next = p.next, first;
1413	>	int h = p.hash, j = h & mask;
1414	>	if ((first = tabAt(tab, j)) == null)
1415	>	insertAtFront = true;
1416		else {
1417	<	oldValue = null;
1418	<	++modCount;
1419	<	tab[index] = new HashEntry<K,V>(key, hash, first, value);
1420	<	count = c; // write-volatile
1417	>	K k = p.key;
1418	>	if (first.hash < 0) {
1419	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1420	>	if (t.putTreeVal(h, k, p.val) == null)
1421	>	++added;
1422	>	insertAtFront = false;
1423	>	}
1424	>	else {
1425	>	int binCount = 0;
1426	>	insertAtFront = true;
1427	>	Node<K,V> q; K qk;
1428	>	for (q = first; q != null; q = q.next) {
1429	>	if (q.hash == h &&
1430	>	((qk = q.key) == k ||
1431	>	(qk != null && k.equals(qk)))) {
1432	>	insertAtFront = false;
1433	>	break;
1434	>	}
1435	>	++binCount;
1436	>	}
1437	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1438	>	insertAtFront = false;
1439	>	++added;
1440	>	p.next = first;
1441	>	TreeNode<K,V> hd = null, tl = null;
1442	>	for (q = p; q != null; q = q.next) {
1443	>	TreeNode<K,V> t = new TreeNode<K,V>
1444	>	(q.hash, q.key, q.val, null, null);
1445	>	if ((t.prev = tl) == null)
1446	>	hd = t;
1447	>	else
1448	>	tl.next = t;
1449	>	tl = t;
1450	>	}
1451	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1452	>	}
1453	>	}
1454		}
1455	<	return oldValue;
1456	<	} finally {
1457	<	unlock();
1455	>	if (insertAtFront) {
1456	>	++added;
1457	>	p.next = first;
1458	>	setTabAt(tab, j, p);
1459	>	}
1460	>	p = next;
1461		}
1462	+	table = tab;
1463	+	sizeCtl = n - (n >>> 2);
1464	+	baseCount = added;
1465		}
1466	+	}
1467
1468	<	void rehash() {
439	<	HashEntry[] oldTable = table;
440	<	int oldCapacity = oldTable.length;
441	<	if (oldCapacity >= MAXIMUM_CAPACITY)
442	<	return;
1468	>	// ConcurrentMap methods
1469
1470	<	/*
1471	<	* Reclassify nodes in each list to new Map.  Because we are
1472	<	* using power-of-two expansion, the elements from each bin
1473	<	* must either stay at same index, or move with a power of two
1474	<	* offset. We eliminate unnecessary node creation by catching
1475	<	* cases where old nodes can be reused because their next
1476	<	* fields won't change. Statistically, at the default
1477	<	* threshold, only about one-sixth of them need cloning when
1478	<	* a table doubles. The nodes they replace will be garbage
1479	<	* collectable as soon as they are no longer referenced by any
454	<	* reader thread that may be in the midst of traversing table
455	<	* right now.
456	<	*/
457	<
458	<	HashEntry[] newTable = new HashEntry[oldCapacity << 1];
459	<	threshold = (int)(newTable.length * loadFactor);
460	<	int sizeMask = newTable.length - 1;
461	<	for (int i = 0; i < oldCapacity ; i++) {
462	<	// We need to guarantee that any existing reads of old Map can
463	<	//  proceed. So we cannot yet null out each bin.
464	<	HashEntry<K,V> e = (HashEntry<K,V>)oldTable[i];
465	<
466	<	if (e != null) {
467	<	HashEntry<K,V> next = e.next;
468	<	int idx = e.hash & sizeMask;
469	<
470	<	//  Single node on list
471	<	if (next == null)
472	<	newTable[idx] = e;
1470	>	/**
1471	>	* {@inheritDoc}
1472	>	*
1473	>	* @return the previous value associated with the specified key,
1474	>	*         or {@code null} if there was no mapping for the key
1475	>	* @throws NullPointerException if the specified key or value is null
1476	>	*/
1477	>	public V putIfAbsent(K key, V value) {
1478	>	return putVal(key, value, true);
1479	>	}
1480
1481	<	else {
1482	<	// Reuse trailing consecutive sequence at same slot
1483	<	HashEntry<K,V> lastRun = e;
1484	<	int lastIdx = idx;
1485	<	for (HashEntry<K,V> last = next;
1486	<	last != null;
1487	<	last = last.next) {
1488	<	int k = last.hash & sizeMask;
1489	<	if (k != lastIdx) {
1490	<	lastIdx = k;
1491	<	lastRun = last;
1481	>	/**
1482	>	* {@inheritDoc}
1483	>	*
1484	>	* @throws NullPointerException if the specified key is null
1485	>	*/
1486	>	public boolean remove(Object key, Object value) {
1487	>	if (key == null)
1488	>	throw new NullPointerException();
1489	>	return value != null && replaceNode(key, null, value) != null;
1490	>	}
1491	>
1492	>	/**
1493	>	* {@inheritDoc}
1494	>	*
1495	>	* @throws NullPointerException if any of the arguments are null
1496	>	*/
1497	>	public boolean replace(K key, V oldValue, V newValue) {
1498	>	if (key == null || oldValue == null || newValue == null)
1499	>	throw new NullPointerException();
1500	>	return replaceNode(key, newValue, oldValue) != null;
1501	>	}
1502	>
1503	>	/**
1504	>	* {@inheritDoc}
1505	>	*
1506	>	* @return the previous value associated with the specified key,
1507	>	*         or {@code null} if there was no mapping for the key
1508	>	* @throws NullPointerException if the specified key or value is null
1509	>	*/
1510	>	public V replace(K key, V value) {
1511	>	if (key == null || value == null)
1512	>	throw new NullPointerException();
1513	>	return replaceNode(key, value, null);
1514	>	}
1515	>
1516	>	// Overrides of JDK8+ Map extension method defaults
1517	>
1518	>	/**
1519	>	* Returns the value to which the specified key is mapped, or the
1520	>	* given default value if this map contains no mapping for the
1521	>	* key.
1522	>	*
1523	>	* @param key the key whose associated value is to be returned
1524	>	* @param defaultValue the value to return if this map contains
1525	>	* no mapping for the given key
1526	>	* @return the mapping for the key, if present; else the default value
1527	>	* @throws NullPointerException if the specified key is null
1528	>	*/
1529	>	public V getOrDefault(Object key, V defaultValue) {
1530	>	V v;
1531	>	return (v = get(key)) == null ? defaultValue : v;
1532	>	}
1533	>
1534	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1535	>	if (action == null) throw new NullPointerException();
1536	>	Node<K,V>[] t;
1537	>	if ((t = table) != null) {
1538	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1539	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1540	>	action.accept(p.key, p.val);
1541	>	}
1542	>	}
1543	>	}
1544	>
1545	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1546	>	if (function == null) throw new NullPointerException();
1547	>	Node<K,V>[] t;
1548	>	if ((t = table) != null) {
1549	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1550	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1551	>	V oldValue = p.val;
1552	>	for (K key = p.key;;) {
1553	>	V newValue = function.apply(key, oldValue);
1554	>	if (newValue == null)
1555	>	throw new NullPointerException();
1556	>	if (replaceNode(key, newValue, oldValue) != null ||
1557	>	(oldValue = get(key)) == null)
1558	>	break;
1559	>	}
1560	>	}
1561	>	}
1562	>	}
1563	>
1564	>	/**
1565	>	* If the specified key is not already associated with a value,
1566	>	* attempts to compute its value using the given mapping function
1567	>	* and enters it into this map unless {@code null}.  The entire
1568	>	* method invocation is performed atomically, so the function is
1569	>	* applied at most once per key.  Some attempted update operations
1570	>	* on this map by other threads may be blocked while computation
1571	>	* is in progress, so the computation should be short and simple,
1572	>	* and must not attempt to update any other mappings of this map.
1573	>	*
1574	>	* @param key key with which the specified value is to be associated
1575	>	* @param mappingFunction the function to compute a value
1576	>	* @return the current (existing or computed) value associated with
1577	>	*         the specified key, or null if the computed value is null
1578	>	* @throws NullPointerException if the specified key or mappingFunction
1579	>	*         is null
1580	>	* @throws IllegalStateException if the computation detectably
1581	>	*         attempts a recursive update to this map that would
1582	>	*         otherwise never complete
1583	>	* @throws RuntimeException or Error if the mappingFunction does so,
1584	>	*         in which case the mapping is left unestablished
1585	>	*/
1586	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1587	>	if (key == null || mappingFunction == null)
1588	>	throw new NullPointerException();
1589	>	int h = spread(key.hashCode());
1590	>	V val = null;
1591	>	int binCount = 0;
1592	>	for (Node<K,V>[] tab = table;;) {
1593	>	Node<K,V> f; int n, i, fh;
1594	>	if (tab == null || (n = tab.length) == 0)
1595	>	tab = initTable();
1596	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1597	>	Node<K,V> r = new ReservationNode<K,V>();
1598	>	synchronized (r) {
1599	>	if (casTabAt(tab, i, null, r)) {
1600	>	binCount = 1;
1601	>	Node<K,V> node = null;
1602	>	try {
1603	>	if ((val = mappingFunction.apply(key)) != null)
1604	>	node = new Node<K,V>(h, key, val, null);
1605	>	} finally {
1606	>	setTabAt(tab, i, node);
1607	>	}
1608	>	}
1609	>	}
1610	>	if (binCount != 0)
1611	>	break;
1612	>	}
1613	>	else if ((fh = f.hash) == MOVED)
1614	>	tab = helpTransfer(tab, f);
1615	>	else {
1616	>	boolean added = false;
1617	>	synchronized (f) {
1618	>	if (tabAt(tab, i) == f) {
1619	>	if (fh >= 0) {
1620	>	binCount = 1;
1621	>	for (Node<K,V> e = f;; ++binCount) {
1622	>	K ek; V ev;
1623	>	if (e.hash == h &&
1624	>	((ek = e.key) == key ||
1625	>	(ek != null && key.equals(ek)))) {
1626	>	val = e.val;
1627	>	break;
1628	>	}
1629	>	Node<K,V> pred = e;
1630	>	if ((e = e.next) == null) {
1631	>	if ((val = mappingFunction.apply(key)) != null) {
1632	>	added = true;
1633	>	pred.next = new Node<K,V>(h, key, val, null);
1634	>	}
1635	>	break;
1636	>	}
1637		}
1638		}
1639	<	newTable[lastIdx] = lastRun;
1639	>	else if (f instanceof TreeBin) {
1640	>	binCount = 2;
1641	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1642	>	TreeNode<K,V> r, p;
1643	>	if ((r = t.root) != null &&
1644	>	(p = r.findTreeNode(h, key, null)) != null)
1645	>	val = p.val;
1646	>	else if ((val = mappingFunction.apply(key)) != null) {
1647	>	added = true;
1648	>	t.putTreeVal(h, key, val);
1649	>	}
1650	>	}
1651	>	}
1652	>	}
1653	>	if (binCount != 0) {
1654	>	if (binCount >= TREEIFY_THRESHOLD)
1655	>	treeifyBin(tab, i);
1656	>	if (!added)
1657	>	return val;
1658	>	break;
1659	>	}
1660	>	}
1661	>	}
1662	>	if (val != null)
1663	>	addCount(1L, binCount);
1664	>	return val;
1665	>	}
1666
1667	<	// Clone all remaining nodes
1668	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1669	<	int k = p.hash & sizeMask;
1670	<	HashEntry<K,V> n = (HashEntry<K,V>)newTable[k];
1671	<	newTable[k] = new HashEntry<K,V>(p.key, p.hash,
1672	<	n, p.value);
1667	>	/**
1668	>	* If the value for the specified key is present, attempts to
1669	>	* compute a new mapping given the key and its current mapped
1670	>	* value.  The entire method invocation is performed atomically.
1671	>	* Some attempted update operations on this map by other threads
1672	>	* may be blocked while computation is in progress, so the
1673	>	* computation should be short and simple, and must not attempt to
1674	>	* update any other mappings of this map.
1675	>	*
1676	>	* @param key key with which a value may be associated
1677	>	* @param remappingFunction the function to compute a value
1678	>	* @return the new value associated with the specified key, or null if none
1679	>	* @throws NullPointerException if the specified key or remappingFunction
1680	>	*         is null
1681	>	* @throws IllegalStateException if the computation detectably
1682	>	*         attempts a recursive update to this map that would
1683	>	*         otherwise never complete
1684	>	* @throws RuntimeException or Error if the remappingFunction does so,
1685	>	*         in which case the mapping is unchanged
1686	>	*/
1687	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1688	>	if (key == null || remappingFunction == null)
1689	>	throw new NullPointerException();
1690	>	int h = spread(key.hashCode());
1691	>	V val = null;
1692	>	int delta = 0;
1693	>	int binCount = 0;
1694	>	for (Node<K,V>[] tab = table;;) {
1695	>	Node<K,V> f; int n, i, fh;
1696	>	if (tab == null || (n = tab.length) == 0)
1697	>	tab = initTable();
1698	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1699	>	break;
1700	>	else if ((fh = f.hash) == MOVED)
1701	>	tab = helpTransfer(tab, f);
1702	>	else {
1703	>	synchronized (f) {
1704	>	if (tabAt(tab, i) == f) {
1705	>	if (fh >= 0) {
1706	>	binCount = 1;
1707	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1708	>	K ek;
1709	>	if (e.hash == h &&
1710	>	((ek = e.key) == key ||
1711	>	(ek != null && key.equals(ek)))) {
1712	>	val = remappingFunction.apply(key, e.val);
1713	>	if (val != null)
1714	>	e.val = val;
1715	>	else {
1716	>	delta = -1;
1717	>	Node<K,V> en = e.next;
1718	>	if (pred != null)
1719	>	pred.next = en;
1720	>	else
1721	>	setTabAt(tab, i, en);
1722	>	}
1723	>	break;
1724	>	}
1725	>	pred = e;
1726	>	if ((e = e.next) == null)
1727	>	break;
1728	>	}
1729	>	}
1730	>	else if (f instanceof TreeBin) {
1731	>	binCount = 2;
1732	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1733	>	TreeNode<K,V> r, p;
1734	>	if ((r = t.root) != null &&
1735	>	(p = r.findTreeNode(h, key, null)) != null) {
1736	>	val = remappingFunction.apply(key, p.val);
1737	>	if (val != null)
1738	>	p.val = val;
1739	>	else {
1740	>	delta = -1;
1741	>	if (t.removeTreeNode(p))
1742	>	setTabAt(tab, i, untreeify(t.first));
1743	>	}
1744	>	}
1745		}
1746		}
1747		}
1748	+	if (binCount != 0)
1749	+	break;
1750		}
499	–	table = newTable;
1751		}
1752	+	if (delta != 0)
1753	+	addCount((long)delta, binCount);
1754	+	return val;
1755	+	}
1756
1757	<	/**
1758	<	* Remove; match on key only if value null, else match both.
1759	<	*/
1760	<	V remove(Object key, int hash, Object value) {
1761	<	lock();
1762	<	try {
1763	<	int c = count - 1;
1764	<	HashEntry[] tab = table;
1765	<	int index = hash & (tab.length - 1);
1766	<	HashEntry<K,V> first = (HashEntry<K,V>)tab[index];
1767	<	HashEntry<K,V> e = first;
1768	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
1769	<	e = e.next;
1770	<
1771	<	V oldValue = null;
1772	<	if (e != null) {
1773	<	V v = e.value;
1774	<	if (value == null || value.equals(v)) {
1775	<	oldValue = v;
1776	<	// All entries following removed node can stay
1777	<	// in list, but all preceding ones need to be
1778	<	// cloned.
1779	<	++modCount;
1780	<	HashEntry<K,V> newFirst = e.next;
1781	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
1782	<	newFirst = new HashEntry<K,V>(p.key, p.hash,
1783	<	newFirst, p.value);
1784	<	tab[index] = newFirst;
1785	<	count = c; // write-volatile
1757	>	/**
1758	>	* Attempts to compute a mapping for the specified key and its
1759	>	* current mapped value (or {@code null} if there is no current
1760	>	* mapping). The entire method invocation is performed atomically.
1761	>	* Some attempted update operations on this map by other threads
1762	>	* may be blocked while computation is in progress, so the
1763	>	* computation should be short and simple, and must not attempt to
1764	>	* update any other mappings of this Map.
1765	>	*
1766	>	* @param key key with which the specified value is to be associated
1767	>	* @param remappingFunction the function to compute a value
1768	>	* @return the new value associated with the specified key, or null if none
1769	>	* @throws NullPointerException if the specified key or remappingFunction
1770	>	*         is null
1771	>	* @throws IllegalStateException if the computation detectably
1772	>	*         attempts a recursive update to this map that would
1773	>	*         otherwise never complete
1774	>	* @throws RuntimeException or Error if the remappingFunction does so,
1775	>	*         in which case the mapping is unchanged
1776	>	*/
1777	>	public V compute(K key,
1778	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1779	>	if (key == null || remappingFunction == null)
1780	>	throw new NullPointerException();
1781	>	int h = spread(key.hashCode());
1782	>	V val = null;
1783	>	int delta = 0;
1784	>	int binCount = 0;
1785	>	for (Node<K,V>[] tab = table;;) {
1786	>	Node<K,V> f; int n, i, fh;
1787	>	if (tab == null || (n = tab.length) == 0)
1788	>	tab = initTable();
1789	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1790	>	Node<K,V> r = new ReservationNode<K,V>();
1791	>	synchronized (r) {
1792	>	if (casTabAt(tab, i, null, r)) {
1793	>	binCount = 1;
1794	>	Node<K,V> node = null;
1795	>	try {
1796	>	if ((val = remappingFunction.apply(key, null)) != null) {
1797	>	delta = 1;
1798	>	node = new Node<K,V>(h, key, val, null);
1799	>	}
1800	>	} finally {
1801	>	setTabAt(tab, i, node);
1802	>	}
1803		}
1804		}
1805	<	return oldValue;
1806	<	} finally {
1807	<	unlock();
1805	>	if (binCount != 0)
1806	>	break;
1807	>	}
1808	>	else if ((fh = f.hash) == MOVED)
1809	>	tab = helpTransfer(tab, f);
1810	>	else {
1811	>	synchronized (f) {
1812	>	if (tabAt(tab, i) == f) {
1813	>	if (fh >= 0) {
1814	>	binCount = 1;
1815	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1816	>	K ek;
1817	>	if (e.hash == h &&
1818	>	((ek = e.key) == key ||
1819	>	(ek != null && key.equals(ek)))) {
1820	>	val = remappingFunction.apply(key, e.val);
1821	>	if (val != null)
1822	>	e.val = val;
1823	>	else {
1824	>	delta = -1;
1825	>	Node<K,V> en = e.next;
1826	>	if (pred != null)
1827	>	pred.next = en;
1828	>	else
1829	>	setTabAt(tab, i, en);
1830	>	}
1831	>	break;
1832	>	}
1833	>	pred = e;
1834	>	if ((e = e.next) == null) {
1835	>	val = remappingFunction.apply(key, null);
1836	>	if (val != null) {
1837	>	delta = 1;
1838	>	pred.next =
1839	>	new Node<K,V>(h, key, val, null);
1840	>	}
1841	>	break;
1842	>	}
1843	>	}
1844	>	}
1845	>	else if (f instanceof TreeBin) {
1846	>	binCount = 1;
1847	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1848	>	TreeNode<K,V> r, p;
1849	>	if ((r = t.root) != null)
1850	>	p = r.findTreeNode(h, key, null);
1851	>	else
1852	>	p = null;
1853	>	V pv = (p == null) ? null : p.val;
1854	>	val = remappingFunction.apply(key, pv);
1855	>	if (val != null) {
1856	>	if (p != null)
1857	>	p.val = val;
1858	>	else {
1859	>	delta = 1;
1860	>	t.putTreeVal(h, key, val);
1861	>	}
1862	>	}
1863	>	else if (p != null) {
1864	>	delta = -1;
1865	>	if (t.removeTreeNode(p))
1866	>	setTabAt(tab, i, untreeify(t.first));
1867	>	}
1868	>	}
1869	>	}
1870	>	}
1871	>	if (binCount != 0) {
1872	>	if (binCount >= TREEIFY_THRESHOLD)
1873	>	treeifyBin(tab, i);
1874	>	break;
1875	>	}
1876		}
1877		}
1878	+	if (delta != 0)
1879	+	addCount((long)delta, binCount);
1880	+	return val;
1881	+	}
1882
1883	<	void clear() {
1884	<	if (count != 0) {
1885	<	lock();
1886	<	try {
1887	<	HashEntry[] tab = table;
1888	<	for (int i = 0; i < tab.length ; i++)
1889	<	tab[i] = null;
1890	<	++modCount;
1891	<	count = 0; // write-volatile
1892	<	} finally {
1893	<	unlock();
1883	>	/**
1884	>	* If the specified key is not already associated with a
1885	>	* (non-null) value, associates it with the given value.
1886	>	* Otherwise, replaces the value with the results of the given
1887	>	* remapping function, or removes if {@code null}. The entire
1888	>	* method invocation is performed atomically.  Some attempted
1889	>	* update operations on this map by other threads may be blocked
1890	>	* while computation is in progress, so the computation should be
1891	>	* short and simple, and must not attempt to update any other
1892	>	* mappings of this Map.
1893	>	*
1894	>	* @param key key with which the specified value is to be associated
1895	>	* @param value the value to use if absent
1896	>	* @param remappingFunction the function to recompute a value if present
1897	>	* @return the new value associated with the specified key, or null if none
1898	>	* @throws NullPointerException if the specified key or the
1899	>	*         remappingFunction is null
1900	>	* @throws RuntimeException or Error if the remappingFunction does so,
1901	>	*         in which case the mapping is unchanged
1902	>	*/
1903	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1904	>	if (key == null || value == null || remappingFunction == null)
1905	>	throw new NullPointerException();
1906	>	int h = spread(key.hashCode());
1907	>	V val = null;
1908	>	int delta = 0;
1909	>	int binCount = 0;
1910	>	for (Node<K,V>[] tab = table;;) {
1911	>	Node<K,V> f; int n, i, fh;
1912	>	if (tab == null || (n = tab.length) == 0)
1913	>	tab = initTable();
1914	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1915	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1916	>	delta = 1;
1917	>	val = value;
1918	>	break;
1919	>	}
1920	>	}
1921	>	else if ((fh = f.hash) == MOVED)
1922	>	tab = helpTransfer(tab, f);
1923	>	else {
1924	>	synchronized (f) {
1925	>	if (tabAt(tab, i) == f) {
1926	>	if (fh >= 0) {
1927	>	binCount = 1;
1928	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1929	>	K ek;
1930	>	if (e.hash == h &&
1931	>	((ek = e.key) == key ||
1932	>	(ek != null && key.equals(ek)))) {
1933	>	val = remappingFunction.apply(e.val, value);
1934	>	if (val != null)
1935	>	e.val = val;
1936	>	else {
1937	>	delta = -1;
1938	>	Node<K,V> en = e.next;
1939	>	if (pred != null)
1940	>	pred.next = en;
1941	>	else
1942	>	setTabAt(tab, i, en);
1943	>	}
1944	>	break;
1945	>	}
1946	>	pred = e;
1947	>	if ((e = e.next) == null) {
1948	>	delta = 1;
1949	>	val = value;
1950	>	pred.next =
1951	>	new Node<K,V>(h, key, val, null);
1952	>	break;
1953	>	}
1954	>	}
1955	>	}
1956	>	else if (f instanceof TreeBin) {
1957	>	binCount = 2;
1958	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1959	>	TreeNode<K,V> r = t.root;
1960	>	TreeNode<K,V> p = (r == null) ? null :
1961	>	r.findTreeNode(h, key, null);
1962	>	val = (p == null) ? value :
1963	>	remappingFunction.apply(p.val, value);
1964	>	if (val != null) {
1965	>	if (p != null)
1966	>	p.val = val;
1967	>	else {
1968	>	delta = 1;
1969	>	t.putTreeVal(h, key, val);
1970	>	}
1971	>	}
1972	>	else if (p != null) {
1973	>	delta = -1;
1974	>	if (t.removeTreeNode(p))
1975	>	setTabAt(tab, i, untreeify(t.first));
1976	>	}
1977	>	}
1978	>	}
1979	>	}
1980	>	if (binCount != 0) {
1981	>	if (binCount >= TREEIFY_THRESHOLD)
1982	>	treeifyBin(tab, i);
1983	>	break;
1984		}
1985		}
1986		}
1987	+	if (delta != 0)
1988	+	addCount((long)delta, binCount);
1989	+	return val;
1990		}
1991
1992	+	// Hashtable legacy methods
1993
1994	+	/**
1995	+	* Legacy method testing if some key maps into the specified value
1996	+	* in this table.  This method is identical in functionality to
1997	+	* {@link #containsValue(Object)}, and exists solely to ensure
1998	+	* full compatibility with class {@link java.util.Hashtable},
1999	+	* which supported this method prior to introduction of the
2000	+	* Java Collections framework.
2001	+	*
2002	+	* @param  value a value to search for
2003	+	* @return {@code true} if and only if some key maps to the
2004	+	*         {@code value} argument in this table as
2005	+	*         determined by the {@code equals} method;
2006	+	*         {@code false} otherwise
2007	+	* @throws NullPointerException if the specified value is null
2008	+	*/
2009	+	@Deprecated public boolean contains(Object value) {
2010	+	return containsValue(value);
2011	+	}
2012
2013	<	/* ---------------- Public operations -------------- */
2013	>	/**
2014	>	* Returns an enumeration of the keys in this table.
2015	>	*
2016	>	* @return an enumeration of the keys in this table
2017	>	* @see #keySet()
2018	>	*/
2019	>	public Enumeration<K> keys() {
2020	>	Node<K,V>[] t;
2021	>	int f = (t = table) == null ? 0 : t.length;
2022	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2023	>	}
2024
2025		/**
2026	<	* Creates a new, empty map with the specified initial
561	<	* capacity, load factor and concurrency level.
2026	>	* Returns an enumeration of the values in this table.
2027		*
2028	<	* @param initialCapacity the initial capacity. The implementation
2029	<	* performs internal sizing to accommodate this many elements.
565	<	* @param loadFactor  the load factor threshold, used to control resizing.
566	<	* Resizing may be performed when the average number of elements per
567	<	* bin exceeds this threshold.
568	<	* @param concurrencyLevel the estimated number of concurrently
569	<	* updating threads. The implementation performs internal sizing
570	<	* to try to accommodate this many threads.
571	<	* @throws IllegalArgumentException if the initial capacity is
572	<	* negative or the load factor or concurrencyLevel are
573	<	* nonpositive.
2028	>	* @return an enumeration of the values in this table
2029	>	* @see #values()
2030		*/
2031	<	public ConcurrentHashMap(int initialCapacity,
2032	<	float loadFactor, int concurrencyLevel) {
2033	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
2034	<	throw new IllegalArgumentException();
2031	>	public Enumeration<V> elements() {
2032	>	Node<K,V>[] t;
2033	>	int f = (t = table) == null ? 0 : t.length;
2034	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2035	>	}
2036
2037	<	if (concurrencyLevel > MAX_SEGMENTS)
581	<	concurrencyLevel = MAX_SEGMENTS;
2037	>	// ConcurrentHashMap-only methods
2038
2039	<	// Find power-of-two sizes best matching arguments
2040	<	int sshift = 0;
2041	<	int ssize = 1;
2042	<	while (ssize < concurrencyLevel) {
2043	<	++sshift;
2044	<	ssize <<= 1;
2045	<	}
2046	<	segmentShift = 32 - sshift;
2047	<	segmentMask = ssize - 1;
2048	<	this.segments = new Segment[ssize];
2049	<
2050	<	if (initialCapacity > MAXIMUM_CAPACITY)
2051	<	initialCapacity = MAXIMUM_CAPACITY;
596	<	int c = initialCapacity / ssize;
597	<	if (c * ssize < initialCapacity)
598	<	++c;
599	<	int cap = 1;
600	<	while (cap < c)
601	<	cap <<= 1;
602	<
603	<	for (int i = 0; i < this.segments.length; ++i)
604	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
2039	>	/**
2040	>	* Returns the number of mappings. This method should be used
2041	>	* instead of {@link #size} because a ConcurrentHashMap may
2042	>	* contain more mappings than can be represented as an int. The
2043	>	* value returned is an estimate; the actual count may differ if
2044	>	* there are concurrent insertions or removals.
2045	>	*
2046	>	* @return the number of mappings
2047	>	* @since 1.8
2048	>	*/
2049	>	public long mappingCount() {
2050	>	long n = sumCount();
2051	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2052		}
2053
2054		/**
2055	<	* Creates a new, empty map with the specified initial capacity
2056	<	* and load factor and with the default concurrencyLevel
2057	<	* (<tt>16</tt>).
2055	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2056	>	* from the given type to {@code Boolean.TRUE}.
2057	>	*
2058	>	* @param <K> the element type of the returned set
2059	>	* @return the new set
2060	>	* @since 1.8
2061	>	*/
2062	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2063	>	return new KeySetView<K,Boolean>
2064	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2065	>	}
2066	>
2067	>	/**
2068	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2069	>	* from the given type to {@code Boolean.TRUE}.
2070		*
2071		* @param initialCapacity The implementation performs internal
2072		* sizing to accommodate this many elements.
2073	<	* @param loadFactor  the load factor threshold, used to control resizing.
2073	>	* @param <K> the element type of the returned set
2074		* @throws IllegalArgumentException if the initial capacity of
2075	<	* elements is negative or the load factor is nonpositive
2076	<	*/
2077	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2078	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2075	>	* elements is negative
2076	>	* @return the new set
2077	>	* @since 1.8
2078	>	*/
2079	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2080	>	return new KeySetView<K,Boolean>
2081	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2082		}
2083
2084		/**
2085	<	* Creates a new, empty map with the specified initial capacity,
2086	<	* and with default load factor (<tt>0.75f</tt>)
2087	<	* and concurrencyLevel (<tt>16</tt>).
2085	>	* Returns a {@link Set} view of the keys in this map, using the
2086	>	* given common mapped value for any additions (i.e., {@link
2087	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2088	>	* This is of course only appropriate if it is acceptable to use
2089	>	* the same value for all additions from this view.
2090		*
2091	<	* @param initialCapacity the initial capacity. The implementation
2092	<	* performs internal sizing to accommodate this many elements.
2093	<	* @throws IllegalArgumentException if the initial capacity of
630	<	* elements is negative.
2091	>	* @param mappedValue the mapped value to use for any additions
2092	>	* @return the set view
2093	>	* @throws NullPointerException if the mappedValue is null
2094		*/
2095	<	public ConcurrentHashMap(int initialCapacity) {
2096	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2095	>	public KeySetView<K,V> keySet(V mappedValue) {
2096	>	if (mappedValue == null)
2097	>	throw new NullPointerException();
2098	>	return new KeySetView<K,V>(this, mappedValue);
2099		}
2100
2101	+	/* ---------------- Special Nodes -------------- */
2102	+
2103		/**
2104	<	* Creates a new, empty map with a default initial capacity
638	<	* (<tt>16</tt>), load factor
639	<	* (<tt>0.75f</tt>), and concurrencyLevel
640	<	* (<tt>16</tt>).
2104	>	* A node inserted at head of bins during transfer operations.
2105		*/
2106	<	public ConcurrentHashMap() {
2107	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2106	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2107	>	final Node<K,V>[] nextTable;
2108	>	ForwardingNode(Node<K,V>[] tab) {
2109	>	super(MOVED, null, null, null);
2110	>	this.nextTable = tab;
2111	>	}
2112	>
2113	>	Node<K,V> find(int h, Object k) {
2114	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2115	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2116	>	Node<K,V> e; int n;
2117	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2118	>	(e = tabAt(tab, (n - 1) & h)) == null)
2119	>	return null;
2120	>	for (;;) {
2121	>	int eh; K ek;
2122	>	if ((eh = e.hash) == h &&
2123	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2124	>	return e;
2125	>	if (eh < 0) {
2126	>	if (e instanceof ForwardingNode) {
2127	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2128	>	continue outer;
2129	>	}
2130	>	else
2131	>	return e.find(h, k);
2132	>	}
2133	>	if ((e = e.next) == null)
2134	>	return null;
2135	>	}
2136	>	}
2137	>	}
2138		}
2139
2140		/**
2141	<	* Creates a new map with the same mappings as the given map.  The
648	<	* map is created with a capacity of 1.5 times the number of
649	<	* mappings in the given map or <tt>16</tt>
650	<	* (whichever is greater), and a default load factor
651	<	* (<tt>0.75f</tt>) and concurrencyLevel
652	<	* (<tt>16</tt>).
653	<	* @param t the map
2141	>	* A place-holder node used in computeIfAbsent and compute
2142		*/
2143	<	public ConcurrentHashMap(Map<? extends K, ? extends V> t) {
2144	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
2145	<	DEFAULT_INITIAL_CAPACITY),
2146	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2147	<	putAll(t);
2143	>	static final class ReservationNode<K,V> extends Node<K,V> {
2144	>	ReservationNode() {
2145	>	super(RESERVED, null, null, null);
2146	>	}
2147	>
2148	>	Node<K,V> find(int h, Object k) {
2149	>	return null;
2150	>	}
2151		}
2152
2153	+	/* ---------------- Table Initialization and Resizing -------------- */
2154	+
2155		/**
2156	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
2156	>	* Initializes table, using the size recorded in sizeCtl.
2157	>	*/
2158	>	private final Node<K,V>[] initTable() {
2159	>	Node<K,V>[] tab; int sc;
2160	>	while ((tab = table) == null || tab.length == 0) {
2161	>	if ((sc = sizeCtl) < 0)
2162	>	Thread.yield(); // lost initialization race; just spin
2163	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2164	>	try {
2165	>	if ((tab = table) == null || tab.length == 0) {
2166	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2167	>	@SuppressWarnings({"rawtypes","unchecked"})
2168	>	Node<K,V>[] nt = (Node<K,V>[])new Node[n];
2169	>	table = tab = nt;
2170	>	sc = n - (n >>> 2);
2171	>	}
2172	>	} finally {
2173	>	sizeCtl = sc;
2174	>	}
2175	>	break;
2176	>	}
2177	>	}
2178	>	return tab;
2179	>	}
2180	>
2181	>	/**
2182	>	* Adds to count, and if table is too small and not already
2183	>	* resizing, initiates transfer. If already resizing, helps
2184	>	* perform transfer if work is available.  Rechecks occupancy
2185	>	* after a transfer to see if another resize is already needed
2186	>	* because resizings are lagging additions.
2187		*
2188	<	* @return <tt>true</tt> if this map contains no key-value mappings.
2188	>	* @param x the count to add
2189	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2190		*/
2191	<	public boolean isEmpty() {
2192	<	final Segment[] segments = this.segments;
2193	<	/*
2194	<	* We keep track of per-segment modCounts to avoid ABA
2195	<	* problems in which an element in one segment was added and
2196	<	* in another removed during traversal, in which case the
2197	<	* table was never actually empty at any point. Note the
2198	<	* similar use of modCounts in the size() and containsValue()
2199	<	* methods, which are the only other methods also susceptible
2200	<	* to ABA problems.
2201	<	*/
2202	<	int[] mc = new int[segments.length];
2203	<	int mcsum = 0;
2204	<	for (int i = 0; i < segments.length; ++i) {
2205	<	if (segments[i].count != 0)
2206	<	return false;
683	<	else
684	<	mcsum += mc[i] = segments[i].modCount;
2191	>	private final void addCount(long x, int check) {
2192	>	CounterCell[] as; long b, s;
2193	>	if ((as = counterCells) != null ||
2194	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2195	>	CounterCell a; long v; int m;
2196	>	boolean uncontended = true;
2197	>	if (as == null || (m = as.length - 1) < 0 ||
2198	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2199	>	!(uncontended =
2200	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2201	>	fullAddCount(x, uncontended);
2202	>	return;
2203	>	}
2204	>	if (check <= 1)
2205	>	return;
2206	>	s = sumCount();
2207		}
2208	<	// If mcsum happens to be zero, then we know we got a snapshot
2209	<	// before any modifications at all were made.  This is
2210	<	// probably common enough to bother tracking.
2211	<	if (mcsum != 0) {
2212	<	for (int i = 0; i < segments.length; ++i) {
2213	<	if (segments[i].count != 0 ||
2214	<	mc[i] != segments[i].modCount)
2215	<	return false;
2208	>	if (check >= 0) {
2209	>	Node<K,V>[] tab, nt; int sc;
2210	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2211	>	tab.length < MAXIMUM_CAPACITY) {
2212	>	if (sc < 0) {
2213	>	if (sc == -1 || transferIndex <= transferOrigin ||
2214	>	(nt = nextTable) == null)
2215	>	break;
2216	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
2217	>	transfer(tab, nt);
2218	>	}
2219	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
2220	>	transfer(tab, null);
2221	>	s = sumCount();
2222		}
2223		}
696	–	return true;
2224		}
2225
2226		/**
2227	<	* Returns the number of key-value mappings in this map.  If the
2228	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
2229	<	* <tt>Integer.MAX_VALUE</tt>.
2227	>	* Helps transfer if a resize is in progress.
2228	>	*/
2229	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2230	>	Node<K,V>[] nextTab; int sc;
2231	>	if ((f instanceof ForwardingNode) &&
2232	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2233	>	if (nextTab == nextTable && tab == table &&
2234	>	transferIndex > transferOrigin && (sc = sizeCtl) < -1 &&
2235	>	U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
2236	>	transfer(tab, nextTab);
2237	>	return nextTab;
2238	>	}
2239	>	return table;
2240	>	}
2241	>
2242	>	/**
2243	>	* Tries to presize table to accommodate the given number of elements.
2244		*
2245	<	* @return the number of key-value mappings in this map.
2245	>	* @param size number of elements (doesn't need to be perfectly accurate)
2246		*/
2247	<	public int size() {
2248	<	final Segment[] segments = this.segments;
2249	<	long sum = 0;
2250	<	long check = 0;
2251	<	int[] mc = new int[segments.length];
2252	<	// Try a few times to get accurate count. On failure due to
2253	<	// continuous async changes in table, resort to locking.
2254	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
2255	<	check = 0;
2256	<	sum = 0;
2257	<	int mcsum = 0;
2258	<	for (int i = 0; i < segments.length; ++i) {
2259	<	sum += segments[i].count;
2260	<	mcsum += mc[i] = segments[i].modCount;
2261	<	}
2262	<	if (mcsum != 0) {
2263	<	for (int i = 0; i < segments.length; ++i) {
2264	<	check += segments[i].count;
724	<	if (mc[i] != segments[i].modCount) {
725	<	check = -1; // force retry
726	<	break;
2247	>	private final void tryPresize(int size) {
2248	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2249	>	tableSizeFor(size + (size >>> 1) + 1);
2250	>	int sc;
2251	>	while ((sc = sizeCtl) >= 0) {
2252	>	Node<K,V>[] tab = table; int n;
2253	>	if (tab == null || (n = tab.length) == 0) {
2254	>	n = (sc > c) ? sc : c;
2255	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2256	>	try {
2257	>	if (table == tab) {
2258	>	@SuppressWarnings({"rawtypes","unchecked"})
2259	>	Node<K,V>[] nt = (Node<K,V>[])new Node[n];
2260	>	table = nt;
2261	>	sc = n - (n >>> 2);
2262	>	}
2263	>	} finally {
2264	>	sizeCtl = sc;
2265		}
2266		}
2267		}
2268	<	if (check == sum)
2268	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2269		break;
2270	+	else if (tab == table &&
2271	+	U.compareAndSwapInt(this, SIZECTL, sc, -2))
2272	+	transfer(tab, null);
2273	+	}
2274	+	}
2275	+
2276	+	/**
2277	+	* Moves and/or copies the nodes in each bin to new table. See
2278	+	* above for explanation.
2279	+	*/
2280	+	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2281	+	int n = tab.length, stride;
2282	+	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2283	+	stride = MIN_TRANSFER_STRIDE; // subdivide range
2284	+	if (nextTab == null) {            // initiating
2285	+	try {
2286	+	@SuppressWarnings({"rawtypes","unchecked"})
2287	+	Node<K,V>[] nt = (Node<K,V>[])new Node[n << 1];
2288	+	nextTab = nt;
2289	+	} catch (Throwable ex) {      // try to cope with OOME
2290	+	sizeCtl = Integer.MAX_VALUE;
2291	+	return;
2292	+	}
2293	+	nextTable = nextTab;
2294	+	transferOrigin = n;
2295	+	transferIndex = n;
2296	+	ForwardingNode<K,V> rev = new ForwardingNode<K,V>(tab);
2297	+	for (int k = n; k > 0;) {    // progressively reveal ready slots
2298	+	int nextk = (k > stride) ? k - stride : 0;
2299	+	for (int m = nextk; m < k; ++m)
2300	+	nextTab[m] = rev;
2301	+	for (int m = n + nextk; m < n + k; ++m)
2302	+	nextTab[m] = rev;
2303	+	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
2304	+	}
2305	+	}
2306	+	int nextn = nextTab.length;
2307	+	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2308	+	boolean advance = true;
2309	+	boolean finishing = false; // to ensure sweep before committing nextTab
2310	+	for (int i = 0, bound = 0;;) {
2311	+	int nextIndex, nextBound, fh; Node<K,V> f;
2312	+	while (advance) {
2313	+	if (--i >= bound || finishing)
2314	+	advance = false;
2315	+	else if ((nextIndex = transferIndex) <= transferOrigin) {
2316	+	i = -1;
2317	+	advance = false;
2318	+	}
2319	+	else if (U.compareAndSwapInt
2320	+	(this, TRANSFERINDEX, nextIndex,
2321	+	nextBound = (nextIndex > stride ?
2322	+	nextIndex - stride : 0))) {
2323	+	bound = nextBound;
2324	+	i = nextIndex - 1;
2325	+	advance = false;
2326	+	}
2327	+	}
2328	+	if (i < 0 || i >= n || i + n >= nextn) {
2329	+	if (finishing) {
2330	+	nextTable = null;
2331	+	table = nextTab;
2332	+	sizeCtl = (n << 1) - (n >>> 1);
2333	+	return;
2334	+	}
2335	+	for (int sc;;) {
2336	+	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
2337	+	if (sc != -1)
2338	+	return;
2339	+	finishing = advance = true;
2340	+	i = n; // recheck before commit
2341	+	break;
2342	+	}
2343	+	}
2344	+	}
2345	+	else if ((f = tabAt(tab, i)) == null) {
2346	+	if (casTabAt(tab, i, null, fwd)) {
2347	+	setTabAt(nextTab, i, null);
2348	+	setTabAt(nextTab, i + n, null);
2349	+	advance = true;
2350	+	}
2351	+	}
2352	+	else if ((fh = f.hash) == MOVED)
2353	+	advance = true; // already processed
2354	+	else {
2355	+	synchronized (f) {
2356	+	if (tabAt(tab, i) == f) {
2357	+	Node<K,V> ln, hn;
2358	+	if (fh >= 0) {
2359	+	int runBit = fh & n;
2360	+	Node<K,V> lastRun = f;
2361	+	for (Node<K,V> p = f.next; p != null; p = p.next) {
2362	+	int b = p.hash & n;
2363	+	if (b != runBit) {
2364	+	runBit = b;
2365	+	lastRun = p;
2366	+	}
2367	+	}
2368	+	if (runBit == 0) {
2369	+	ln = lastRun;
2370	+	hn = null;
2371	+	}
2372	+	else {
2373	+	hn = lastRun;
2374	+	ln = null;
2375	+	}
2376	+	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2377	+	int ph = p.hash; K pk = p.key; V pv = p.val;
2378	+	if ((ph & n) == 0)
2379	+	ln = new Node<K,V>(ph, pk, pv, ln);
2380	+	else
2381	+	hn = new Node<K,V>(ph, pk, pv, hn);
2382	+	}
2383	+	setTabAt(nextTab, i, ln);
2384	+	setTabAt(nextTab, i + n, hn);
2385	+	setTabAt(tab, i, fwd);
2386	+	advance = true;
2387	+	}
2388	+	else if (f instanceof TreeBin) {
2389	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
2390	+	TreeNode<K,V> lo = null, loTail = null;
2391	+	TreeNode<K,V> hi = null, hiTail = null;
2392	+	int lc = 0, hc = 0;
2393	+	for (Node<K,V> e = t.first; e != null; e = e.next) {
2394	+	int h = e.hash;
2395	+	TreeNode<K,V> p = new TreeNode<K,V>
2396	+	(h, e.key, e.val, null, null);
2397	+	if ((h & n) == 0) {
2398	+	if ((p.prev = loTail) == null)
2399	+	lo = p;
2400	+	else
2401	+	loTail.next = p;
2402	+	loTail = p;
2403	+	++lc;
2404	+	}
2405	+	else {
2406	+	if ((p.prev = hiTail) == null)
2407	+	hi = p;
2408	+	else
2409	+	hiTail.next = p;
2410	+	hiTail = p;
2411	+	++hc;
2412	+	}
2413	+	}
2414	+	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2415	+	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2416	+	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2417	+	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2418	+	setTabAt(nextTab, i, ln);
2419	+	setTabAt(nextTab, i + n, hn);
2420	+	setTabAt(tab, i, fwd);
2421	+	advance = true;
2422	+	}
2423	+	}
2424	+	}
2425	+	}
2426		}
733	–	if (check != sum) { // Resort to locking all segments
734	–	sum = 0;
735	–	for (int i = 0; i < segments.length; ++i)
736	–	segments[i].lock();
737	–	for (int i = 0; i < segments.length; ++i)
738	–	sum += segments[i].count;
739	–	for (int i = 0; i < segments.length; ++i)
740	–	segments[i].unlock();
741	–	}
742	–	if (sum > Integer.MAX_VALUE)
743	–	return Integer.MAX_VALUE;
744	–	else
745	–	return (int)sum;
2427		}
2428
2429	+	/* ---------------- Counter support -------------- */
2430
2431		/**
2432	<	* Returns the value to which the specified key is mapped in this table.
2433	<	*
752	<	* @param   key   a key in the table.
753	<	* @return  the value to which the key is mapped in this table;
754	<	*          <tt>null</tt> if the key is not mapped to any value in
755	<	*          this table.
756	<	* @throws  NullPointerException  if the key is
757	<	*               <tt>null</tt>.
2432	>	* A padded cell for distributing counts.  Adapted from LongAdder
2433	>	* and Striped64.  See their internal docs for explanation.
2434		*/
2435	<	public V get(Object key) {
2436	<	int hash = hash(key); // throws NullPointerException if key null
2437	<	return segmentFor(hash).get(key, hash);
2435	>	@sun.misc.Contended static final class CounterCell {
2436	>	volatile long value;
2437	>	CounterCell(long x) { value = x; }
2438	>	}
2439	>
2440	>	final long sumCount() {
2441	>	CounterCell[] as = counterCells; CounterCell a;
2442	>	long sum = baseCount;
2443	>	if (as != null) {
2444	>	for (int i = 0; i < as.length; ++i) {
2445	>	if ((a = as[i]) != null)
2446	>	sum += a.value;
2447	>	}
2448	>	}
2449	>	return sum;
2450	>	}
2451	>
2452	>	// See LongAdder version for explanation
2453	>	private final void fullAddCount(long x, boolean wasUncontended) {
2454	>	int h;
2455	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2456	>	ThreadLocalRandom.localInit();      // force initialization
2457	>	h = ThreadLocalRandom.getProbe();
2458	>	wasUncontended = true;
2459	>	}
2460	>	boolean collide = false;                // True if last slot nonempty
2461	>	for (;;) {
2462	>	CounterCell[] as; CounterCell a; int n; long v;
2463	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2464	>	if ((a = as[(n - 1) & h]) == null) {
2465	>	if (cellsBusy == 0) {            // Try to attach new Cell
2466	>	CounterCell r = new CounterCell(x); // Optimistic create
2467	>	if (cellsBusy == 0 &&
2468	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2469	>	boolean created = false;
2470	>	try {               // Recheck under lock
2471	>	CounterCell[] rs; int m, j;
2472	>	if ((rs = counterCells) != null &&
2473	>	(m = rs.length) > 0 &&
2474	>	rs[j = (m - 1) & h] == null) {
2475	>	rs[j] = r;
2476	>	created = true;
2477	>	}
2478	>	} finally {
2479	>	cellsBusy = 0;
2480	>	}
2481	>	if (created)
2482	>	break;
2483	>	continue;           // Slot is now non-empty
2484	>	}
2485	>	}
2486	>	collide = false;
2487	>	}
2488	>	else if (!wasUncontended)       // CAS already known to fail
2489	>	wasUncontended = true;      // Continue after rehash
2490	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2491	>	break;
2492	>	else if (counterCells != as || n >= NCPU)
2493	>	collide = false;            // At max size or stale
2494	>	else if (!collide)
2495	>	collide = true;
2496	>	else if (cellsBusy == 0 &&
2497	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2498	>	try {
2499	>	if (counterCells == as) {// Expand table unless stale
2500	>	CounterCell[] rs = new CounterCell[n << 1];
2501	>	for (int i = 0; i < n; ++i)
2502	>	rs[i] = as[i];
2503	>	counterCells = rs;
2504	>	}
2505	>	} finally {
2506	>	cellsBusy = 0;
2507	>	}
2508	>	collide = false;
2509	>	continue;                   // Retry with expanded table
2510	>	}
2511	>	h = ThreadLocalRandom.advanceProbe(h);
2512	>	}
2513	>	else if (cellsBusy == 0 && counterCells == as &&
2514	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2515	>	boolean init = false;
2516	>	try {                           // Initialize table
2517	>	if (counterCells == as) {
2518	>	CounterCell[] rs = new CounterCell[2];
2519	>	rs[h & 1] = new CounterCell(x);
2520	>	counterCells = rs;
2521	>	init = true;
2522	>	}
2523	>	} finally {
2524	>	cellsBusy = 0;
2525	>	}
2526	>	if (init)
2527	>	break;
2528	>	}
2529	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2530	>	break;                          // Fall back on using base
2531	>	}
2532		}
2533
2534	+	/* ---------------- Conversion from/to TreeBins -------------- */
2535	+
2536		/**
2537	<	* Tests if the specified object is a key in this table.
2538	<	*
767	<	* @param   key   possible key.
768	<	* @return  <tt>true</tt> if and only if the specified object
769	<	*          is a key in this table, as determined by the
770	<	*          <tt>equals</tt> method; <tt>false</tt> otherwise.
771	<	* @throws  NullPointerException  if the key is
772	<	*               <tt>null</tt>.
2537	>	* Replaces all linked nodes in bin at given index unless table is
2538	>	* too small, in which case resizes instead.
2539		*/
2540	<	public boolean containsKey(Object key) {
2541	<	int hash = hash(key); // throws NullPointerException if key null
2542	<	return segmentFor(hash).containsKey(key, hash);
2540	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2541	>	Node<K,V> b; int n, sc;
2542	>	if (tab != null) {
2543	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY) {
2544	>	if (tab == table && (sc = sizeCtl) >= 0 &&
2545	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
2546	>	transfer(tab, null);
2547	>	}
2548	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2549	>	synchronized (b) {
2550	>	if (tabAt(tab, index) == b) {
2551	>	TreeNode<K,V> hd = null, tl = null;
2552	>	for (Node<K,V> e = b; e != null; e = e.next) {
2553	>	TreeNode<K,V> p =
2554	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2555	>	null, null);
2556	>	if ((p.prev = tl) == null)
2557	>	hd = p;
2558	>	else
2559	>	tl.next = p;
2560	>	tl = p;
2561	>	}
2562	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2563	>	}
2564	>	}
2565	>	}
2566	>	}
2567		}
2568
2569		/**
2570	<	* Returns <tt>true</tt> if this map maps one or more keys to the
781	<	* specified value. Note: This method requires a full internal
782	<	* traversal of the hash table, and so is much slower than
783	<	* method <tt>containsKey</tt>.
784	<	*
785	<	* @param value value whose presence in this map is to be tested.
786	<	* @return <tt>true</tt> if this map maps one or more keys to the
787	<	* specified value.
788	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
2570	>	* Returns a list on non-TreeNodes replacing those in given list.
2571		*/
2572	<	public boolean containsValue(Object value) {
2573	<	if (value == null)
2574	<	throw new NullPointerException();
2572	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2573	>	Node<K,V> hd = null, tl = null;
2574	>	for (Node<K,V> q = b; q != null; q = q.next) {
2575	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2576	>	if (tl == null)
2577	>	hd = p;
2578	>	else
2579	>	tl.next = p;
2580	>	tl = p;
2581	>	}
2582	>	return hd;
2583	>	}
2584
2585	<	// See explanation of modCount use above
2585	>	/* ---------------- TreeNodes -------------- */
2586
2587	<	final Segment[] segments = this.segments;
2588	<	int[] mc = new int[segments.length];
2587	>	/**
2588	>	* Nodes for use in TreeBins
2589	>	*/
2590	>	static final class TreeNode<K,V> extends Node<K,V> {
2591	>	TreeNode<K,V> parent;  // red-black tree links
2592	>	TreeNode<K,V> left;
2593	>	TreeNode<K,V> right;
2594	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2595	>	boolean red;
2596	>
2597	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2598	>	TreeNode<K,V> parent) {
2599	>	super(hash, key, val, next);
2600	>	this.parent = parent;
2601	>	}
2602
2603	<	// Try a few times without locking
2604	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
2605	<	int sum = 0;
2606	<	int mcsum = 0;
2607	<	for (int i = 0; i < segments.length; ++i) {
2608	<	int c = segments[i].count;
2609	<	mcsum += mc[i] = segments[i].modCount;
2610	<	if (segments[i].containsValue(value))
2611	<	return true;
2612	<	}
2613	<	boolean cleanSweep = true;
2614	<	if (mcsum != 0) {
2615	<	for (int i = 0; i < segments.length; ++i) {
2616	<	int c = segments[i].count;
2617	<	if (mc[i] != segments[i].modCount) {
2618	<	cleanSweep = false;
2603	>	Node<K,V> find(int h, Object k) {
2604	>	return findTreeNode(h, k, null);
2605	>	}
2606	>
2607	>	/**
2608	>	* Returns the TreeNode (or null if not found) for the given key
2609	>	* starting at given root.
2610	>	*/
2611	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2612	>	if (k != null) {
2613	>	TreeNode<K,V> p = this;
2614	>	do  {
2615	>	int ph, dir; K pk; TreeNode<K,V> q;
2616	>	TreeNode<K,V> pl = p.left, pr = p.right;
2617	>	if ((ph = p.hash) > h)
2618	>	p = pl;
2619	>	else if (ph < h)
2620	>	p = pr;
2621	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2622	>	return p;
2623	>	else if (pl == null && pr == null)
2624		break;
2625	+	else if ((kc != null ||
2626	+	(kc = comparableClassFor(k)) != null) &&
2627	+	(dir = compareComparables(kc, k, pk)) != 0)
2628	+	p = (dir < 0) ? pl : pr;
2629	+	else if (pl == null)
2630	+	p = pr;
2631	+	else if (pr == null ||
2632	+	(q = pr.findTreeNode(h, k, kc)) == null)
2633	+	p = pl;
2634	+	else
2635	+	return q;
2636	+	} while (p != null);
2637	+	}
2638	+	return null;
2639	+	}
2640	+	}
2641	+
2642	+	/* ---------------- TreeBins -------------- */
2643	+
2644	+	/**
2645	+	* TreeNodes used at the heads of bins. TreeBins do not hold user
2646	+	* keys or values, but instead point to list of TreeNodes and
2647	+	* their root. They also maintain a parasitic read-write lock
2648	+	* forcing writers (who hold bin lock) to wait for readers (who do
2649	+	* not) to complete before tree restructuring operations.
2650	+	*/
2651	+	static final class TreeBin<K,V> extends Node<K,V> {
2652	+	TreeNode<K,V> root;
2653	+	volatile TreeNode<K,V> first;
2654	+	volatile Thread waiter;
2655	+	volatile int lockState;
2656	+	// values for lockState
2657	+	static final int WRITER = 1; // set while holding write lock
2658	+	static final int WAITER = 2; // set when waiting for write lock
2659	+	static final int READER = 4; // increment value for setting read lock
2660	+
2661	+	/**
2662	+	* Creates bin with initial set of nodes headed by b.
2663	+	*/
2664	+	TreeBin(TreeNode<K,V> b) {
2665	+	super(TREEBIN, null, null, null);
2666	+	this.first = b;
2667	+	TreeNode<K,V> r = null;
2668	+	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2669	+	next = (TreeNode<K,V>)x.next;
2670	+	x.left = x.right = null;
2671	+	if (r == null) {
2672	+	x.parent = null;
2673	+	x.red = false;
2674	+	r = x;
2675	+	}
2676	+	else {
2677	+	Object key = x.key;
2678	+	int hash = x.hash;
2679	+	Class<?> kc = null;
2680	+	for (TreeNode<K,V> p = r;;) {
2681	+	int dir, ph;
2682	+	if ((ph = p.hash) > hash)
2683	+	dir = -1;
2684	+	else if (ph < hash)
2685	+	dir = 1;
2686	+	else if ((kc != null ||
2687	+	(kc = comparableClassFor(key)) != null))
2688	+	dir = compareComparables(kc, key, p.key);
2689	+	else
2690	+	dir = 0;
2691	+	TreeNode<K,V> xp = p;
2692	+	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2693	+	x.parent = xp;
2694	+	if (dir <= 0)
2695	+	xp.left = x;
2696	+	else
2697	+	xp.right = x;
2698	+	r = balanceInsertion(r, x);
2699	+	break;
2700	+	}
2701		}
2702		}
2703		}
2704	<	if (cleanSweep)
820	<	return false;
2704	>	this.root = r;
2705		}
2706	<	// Resort to locking all segments
2707	<	for (int i = 0; i < segments.length; ++i)
2708	<	segments[i].lock();
2709	<	boolean found = false;
2710	<	try {
2711	<	for (int i = 0; i < segments.length; ++i) {
2712	<	if (segments[i].containsValue(value)) {
2713	<	found = true;
2706	>
2707	>	/**
2708	>	* Acquires write lock for tree restructuring.
2709	>	*/
2710	>	private final void lockRoot() {
2711	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2712	>	contendedLock(); // offload to separate method
2713	>	}
2714	>
2715	>	/**
2716	>	* Releases write lock for tree restructuring.
2717	>	*/
2718	>	private final void unlockRoot() {
2719	>	lockState = 0;
2720	>	}
2721	>
2722	>	/**
2723	>	* Possibly blocks awaiting root lock.
2724	>	*/
2725	>	private final void contendedLock() {
2726	>	boolean waiting = false;
2727	>	for (int s;;) {
2728	>	if (((s = lockState) & WRITER) == 0) {
2729	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2730	>	if (waiting)
2731	>	waiter = null;
2732	>	return;
2733	>	}
2734	>	}
2735	>	else if ((s | WAITER) == 0) {
2736	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2737	>	waiting = true;
2738	>	waiter = Thread.currentThread();
2739	>	}
2740	>	}
2741	>	else if (waiting)
2742	>	LockSupport.park(this);
2743	>	}
2744	>	}
2745	>
2746	>	/**
2747	>	* Returns matching node or null if none. Tries to search
2748	>	* using tree comparisons from root, but continues linear
2749	>	* search when lock not available.
2750	>	*/
2751	>	final Node<K,V> find(int h, Object k) {
2752	>	if (k != null) {
2753	>	for (Node<K,V> e = first; e != null; e = e.next) {
2754	>	int s; K ek;
2755	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2756	>	if (e.hash == h &&
2757	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2758	>	return e;
2759	>	}
2760	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2761	>	s + READER)) {
2762	>	TreeNode<K,V> r, p;
2763	>	try {
2764	>	p = ((r = root) == null ? null :
2765	>	r.findTreeNode(h, k, null));
2766	>	} finally {
2767	>	Thread w;
2768	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2769	>	(READER|WAITER) && (w = waiter) != null)
2770	>	LockSupport.unpark(w);
2771	>	}
2772	>	return p;
2773	>	}
2774	>	}
2775	>	}
2776	>	return null;
2777	>	}
2778	>
2779	>	/**
2780	>	* Finds or adds a node.
2781	>	* @return null if added
2782	>	*/
2783	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2784	>	Class<?> kc = null;
2785	>	for (TreeNode<K,V> p = root;;) {
2786	>	int dir, ph; K pk; TreeNode<K,V> q, pr;
2787	>	if (p == null) {
2788	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2789		break;
2790		}
2791	+	else if ((ph = p.hash) > h)
2792	+	dir = -1;
2793	+	else if (ph < h)
2794	+	dir = 1;
2795	+	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2796	+	return p;
2797	+	else if ((kc == null &&
2798	+	(kc = comparableClassFor(k)) == null) ||
2799	+	(dir = compareComparables(kc, k, pk)) == 0) {
2800	+	if (p.left == null)
2801	+	dir = 1;
2802	+	else if ((pr = p.right) == null ||
2803	+	(q = pr.findTreeNode(h, k, kc)) == null)
2804	+	dir = -1;
2805	+	else
2806	+	return q;
2807	+	}
2808	+	TreeNode<K,V> xp = p;
2809	+	if ((p = (dir < 0) ? p.left : p.right) == null) {
2810	+	TreeNode<K,V> x, f = first;
2811	+	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2812	+	if (f != null)
2813	+	f.prev = x;
2814	+	if (dir < 0)
2815	+	xp.left = x;
2816	+	else
2817	+	xp.right = x;
2818	+	if (!xp.red)
2819	+	x.red = true;
2820	+	else {
2821	+	lockRoot();
2822	+	try {
2823	+	root = balanceInsertion(root, x);
2824	+	} finally {
2825	+	unlockRoot();
2826	+	}
2827	+	}
2828	+	break;
2829	+	}
2830	+	}
2831	+	assert checkInvariants(root);
2832	+	return null;
2833	+	}
2834	+
2835	+	/**
2836	+	* Removes the given node, that must be present before this
2837	+	* call.  This is messier than typical red-black deletion code
2838	+	* because we cannot swap the contents of an interior node
2839	+	* with a leaf successor that is pinned by "next" pointers
2840	+	* that are accessible independently of lock. So instead we
2841	+	* swap the tree linkages.
2842	+	*
2843	+	* @return true if now too small, so should be untreeified
2844	+	*/
2845	+	final boolean removeTreeNode(TreeNode<K,V> p) {
2846	+	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2847	+	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2848	+	TreeNode<K,V> r, rl;
2849	+	if (pred == null)
2850	+	first = next;
2851	+	else
2852	+	pred.next = next;
2853	+	if (next != null)
2854	+	next.prev = pred;
2855	+	if (first == null) {
2856	+	root = null;
2857	+	return true;
2858	+	}
2859	+	if ((r = root) == null || r.right == null || // too small
2860	+	(rl = r.left) == null || rl.left == null)
2861	+	return true;
2862	+	lockRoot();
2863	+	try {
2864	+	TreeNode<K,V> replacement;
2865	+	TreeNode<K,V> pl = p.left;
2866	+	TreeNode<K,V> pr = p.right;
2867	+	if (pl != null && pr != null) {
2868	+	TreeNode<K,V> s = pr, sl;
2869	+	while ((sl = s.left) != null) // find successor
2870	+	s = sl;
2871	+	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2872	+	TreeNode<K,V> sr = s.right;
2873	+	TreeNode<K,V> pp = p.parent;
2874	+	if (s == pr) { // p was s's direct parent
2875	+	p.parent = s;
2876	+	s.right = p;
2877	+	}
2878	+	else {
2879	+	TreeNode<K,V> sp = s.parent;
2880	+	if ((p.parent = sp) != null) {
2881	+	if (s == sp.left)
2882	+	sp.left = p;
2883	+	else
2884	+	sp.right = p;
2885	+	}
2886	+	if ((s.right = pr) != null)
2887	+	pr.parent = s;
2888	+	}
2889	+	p.left = null;
2890	+	if ((p.right = sr) != null)
2891	+	sr.parent = p;
2892	+	if ((s.left = pl) != null)
2893	+	pl.parent = s;
2894	+	if ((s.parent = pp) == null)
2895	+	r = s;
2896	+	else if (p == pp.left)
2897	+	pp.left = s;
2898	+	else
2899	+	pp.right = s;
2900	+	if (sr != null)
2901	+	replacement = sr;
2902	+	else
2903	+	replacement = p;
2904	+	}
2905	+	else if (pl != null)
2906	+	replacement = pl;
2907	+	else if (pr != null)
2908	+	replacement = pr;
2909	+	else
2910	+	replacement = p;
2911	+	if (replacement != p) {
2912	+	TreeNode<K,V> pp = replacement.parent = p.parent;
2913	+	if (pp == null)
2914	+	r = replacement;
2915	+	else if (p == pp.left)
2916	+	pp.left = replacement;
2917	+	else
2918	+	pp.right = replacement;
2919	+	p.left = p.right = p.parent = null;
2920	+	}
2921	+
2922	+	root = (p.red) ? r : balanceDeletion(r, replacement);
2923	+
2924	+	if (p == replacement) {  // detach pointers
2925	+	TreeNode<K,V> pp;
2926	+	if ((pp = p.parent) != null) {
2927	+	if (p == pp.left)
2928	+	pp.left = null;
2929	+	else if (p == pp.right)
2930	+	pp.right = null;
2931	+	p.parent = null;
2932	+	}
2933	+	}
2934	+	} finally {
2935	+	unlockRoot();
2936	+	}
2937	+	assert checkInvariants(root);
2938	+	return false;
2939	+	}
2940	+
2941	+	/* ------------------------------------------------------------ */
2942	+	// Red-black tree methods, all adapted from CLR
2943	+
2944	+	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2945	+	TreeNode<K,V> p) {
2946	+	TreeNode<K,V> r, pp, rl;
2947	+	if (p != null && (r = p.right) != null) {
2948	+	if ((rl = p.right = r.left) != null)
2949	+	rl.parent = p;
2950	+	if ((pp = r.parent = p.parent) == null)
2951	+	(root = r).red = false;
2952	+	else if (pp.left == p)
2953	+	pp.left = r;
2954	+	else
2955	+	pp.right = r;
2956	+	r.left = p;
2957	+	p.parent = r;
2958	+	}
2959	+	return root;
2960	+	}
2961	+
2962	+	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2963	+	TreeNode<K,V> p) {
2964	+	TreeNode<K,V> l, pp, lr;
2965	+	if (p != null && (l = p.left) != null) {
2966	+	if ((lr = p.left = l.right) != null)
2967	+	lr.parent = p;
2968	+	if ((pp = l.parent = p.parent) == null)
2969	+	(root = l).red = false;
2970	+	else if (pp.right == p)
2971	+	pp.right = l;
2972	+	else
2973	+	pp.left = l;
2974	+	l.right = p;
2975	+	p.parent = l;
2976	+	}
2977	+	return root;
2978	+	}
2979	+
2980	+	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
2981	+	TreeNode<K,V> x) {
2982	+	x.red = true;
2983	+	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
2984	+	if ((xp = x.parent) == null) {
2985	+	x.red = false;
2986	+	return x;
2987	+	}
2988	+	else if (!xp.red || (xpp = xp.parent) == null)
2989	+	return root;
2990	+	if (xp == (xppl = xpp.left)) {
2991	+	if ((xppr = xpp.right) != null && xppr.red) {
2992	+	xppr.red = false;
2993	+	xp.red = false;
2994	+	xpp.red = true;
2995	+	x = xpp;
2996	+	}
2997	+	else {
2998	+	if (x == xp.right) {
2999	+	root = rotateLeft(root, x = xp);
3000	+	xpp = (xp = x.parent) == null ? null : xp.parent;
3001	+	}
3002	+	if (xp != null) {
3003	+	xp.red = false;
3004	+	if (xpp != null) {
3005	+	xpp.red = true;
3006	+	root = rotateRight(root, xpp);
3007	+	}
3008	+	}
3009	+	}
3010	+	}
3011	+	else {
3012	+	if (xppl != null && xppl.red) {
3013	+	xppl.red = false;
3014	+	xp.red = false;
3015	+	xpp.red = true;
3016	+	x = xpp;
3017	+	}
3018	+	else {
3019	+	if (x == xp.left) {
3020	+	root = rotateRight(root, x = xp);
3021	+	xpp = (xp = x.parent) == null ? null : xp.parent;
3022	+	}
3023	+	if (xp != null) {
3024	+	xp.red = false;
3025	+	if (xpp != null) {
3026	+	xpp.red = true;
3027	+	root = rotateLeft(root, xpp);
3028	+	}
3029	+	}
3030	+	}
3031	+	}
3032	+	}
3033	+	}
3034	+
3035	+	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3036	+	TreeNode<K,V> x) {
3037	+	for (TreeNode<K,V> xp, xpl, xpr;;)  {
3038	+	if (x == null || x == root)
3039	+	return root;
3040	+	else if ((xp = x.parent) == null) {
3041	+	x.red = false;
3042	+	return x;
3043	+	}
3044	+	else if (x.red) {
3045	+	x.red = false;
3046	+	return root;
3047	+	}
3048	+	else if ((xpl = xp.left) == x) {
3049	+	if ((xpr = xp.right) != null && xpr.red) {
3050	+	xpr.red = false;
3051	+	xp.red = true;
3052	+	root = rotateLeft(root, xp);
3053	+	xpr = (xp = x.parent) == null ? null : xp.right;
3054	+	}
3055	+	if (xpr == null)
3056	+	x = xp;
3057	+	else {
3058	+	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3059	+	if ((sr == null || !sr.red) &&
3060	+	(sl == null || !sl.red)) {
3061	+	xpr.red = true;
3062	+	x = xp;
3063	+	}
3064	+	else {
3065	+	if (sr == null || !sr.red) {
3066	+	if (sl != null)
3067	+	sl.red = false;
3068	+	xpr.red = true;
3069	+	root = rotateRight(root, xpr);
3070	+	xpr = (xp = x.parent) == null ?
3071	+	null : xp.right;
3072	+	}
3073	+	if (xpr != null) {
3074	+	xpr.red = (xp == null) ? false : xp.red;
3075	+	if ((sr = xpr.right) != null)
3076	+	sr.red = false;
3077	+	}
3078	+	if (xp != null) {
3079	+	xp.red = false;
3080	+	root = rotateLeft(root, xp);
3081	+	}
3082	+	x = root;
3083	+	}
3084	+	}
3085	+	}
3086	+	else { // symmetric
3087	+	if (xpl != null && xpl.red) {
3088	+	xpl.red = false;
3089	+	xp.red = true;
3090	+	root = rotateRight(root, xp);
3091	+	xpl = (xp = x.parent) == null ? null : xp.left;
3092	+	}
3093	+	if (xpl == null)
3094	+	x = xp;
3095	+	else {
3096	+	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3097	+	if ((sl == null || !sl.red) &&
3098	+	(sr == null || !sr.red)) {
3099	+	xpl.red = true;
3100	+	x = xp;
3101	+	}
3102	+	else {
3103	+	if (sl == null || !sl.red) {
3104	+	if (sr != null)
3105	+	sr.red = false;
3106	+	xpl.red = true;
3107	+	root = rotateLeft(root, xpl);
3108	+	xpl = (xp = x.parent) == null ?
3109	+	null : xp.left;
3110	+	}
3111	+	if (xpl != null) {
3112	+	xpl.red = (xp == null) ? false : xp.red;
3113	+	if ((sl = xpl.left) != null)
3114	+	sl.red = false;
3115	+	}
3116	+	if (xp != null) {
3117	+	xp.red = false;
3118	+	root = rotateRight(root, xp);
3119	+	}
3120	+	x = root;
3121	+	}
3122	+	}
3123	+	}
3124	+	}
3125	+	}
3126	+
3127	+	/**
3128	+	* Recursive invariant check
3129	+	*/
3130	+	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3131	+	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3132	+	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3133	+	if (tb != null && tb.next != t)
3134	+	return false;
3135	+	if (tn != null && tn.prev != t)
3136	+	return false;
3137	+	if (tp != null && t != tp.left && t != tp.right)
3138	+	return false;
3139	+	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3140	+	return false;
3141	+	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3142	+	return false;
3143	+	if (t.red && tl != null && tl.red && tr != null && tr.red)
3144	+	return false;
3145	+	if (tl != null && !checkInvariants(tl))
3146	+	return false;
3147	+	if (tr != null && !checkInvariants(tr))
3148	+	return false;
3149	+	return true;
3150	+	}
3151	+
3152	+	private static final sun.misc.Unsafe U;
3153	+	private static final long LOCKSTATE;
3154	+	static {
3155	+	try {
3156	+	U = sun.misc.Unsafe.getUnsafe();
3157	+	Class<?> k = TreeBin.class;
3158	+	LOCKSTATE = U.objectFieldOffset
3159	+	(k.getDeclaredField("lockState"));
3160	+	} catch (Exception e) {
3161	+	throw new Error(e);
3162		}
833	–	} finally {
834	–	for (int i = 0; i < segments.length; ++i)
835	–	segments[i].unlock();
3163		}
837	–	return found;
3164		}
3165
3166	+	/* ----------------Table Traversal -------------- */
3167	+
3168		/**
3169	<	* Legacy method testing if some key maps into the specified value
3170	<	* in this table.  This method is identical in functionality to
3171	<	* {@link #containsValue}, and  exists solely to ensure
3172	<	* full compatibility with class {@link java.util.Hashtable},
3173	<	* which supported this method prior to introduction of the
3174	<	* Java Collections framework.
3169	>	* Encapsulates traversal for methods such as containsValue; also
3170	>	* serves as a base class for other iterators and spliterators.
3171	>	*
3172	>	* Method advance visits once each still-valid node that was
3173	>	* reachable upon iterator construction. It might miss some that
3174	>	* were added to a bin after the bin was visited, which is OK wrt
3175	>	* consistency guarantees. Maintaining this property in the face
3176	>	* of possible ongoing resizes requires a fair amount of
3177	>	* bookkeeping state that is difficult to optimize away amidst
3178	>	* volatile accesses.  Even so, traversal maintains reasonable
3179	>	* throughput.
3180	>	*
3181	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3182	>	* However, if the table has been resized, then all future steps
3183	>	* must traverse both the bin at the current index as well as at
3184	>	* (index + baseSize); and so on for further resizings. To
3185	>	* paranoically cope with potential sharing by users of iterators
3186	>	* across threads, iteration terminates if a bounds checks fails
3187	>	* for a table read.
3188	>	*/
3189	>	static class Traverser<K,V> {
3190	>	Node<K,V>[] tab;        // current table; updated if resized
3191	>	Node<K,V> next;         // the next entry to use
3192	>	int index;              // index of bin to use next
3193	>	int baseIndex;          // current index of initial table
3194	>	int baseLimit;          // index bound for initial table
3195	>	final int baseSize;     // initial table size
3196	>
3197	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3198	>	this.tab = tab;
3199	>	this.baseSize = size;
3200	>	this.baseIndex = this.index = index;
3201	>	this.baseLimit = limit;
3202	>	this.next = null;
3203	>	}
3204
3205	<	* @param      value   a value to search for.
3206	<	* @return     <tt>true</tt> if and only if some key maps to the
3207	<	*             <tt>value</tt> argument in this table as
3208	<	*             determined by the <tt>equals</tt> method;
3209	<	*             <tt>false</tt> otherwise.
3210	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3205	>	/**
3206	>	* Advances if possible, returning next valid node, or null if none.
3207	>	*/
3208	>	final Node<K,V> advance() {
3209	>	Node<K,V> e;
3210	>	if ((e = next) != null)
3211	>	e = e.next;
3212	>	for (;;) {
3213	>	Node<K,V>[] t; int i, n; K ek;  // must use locals in checks
3214	>	if (e != null)
3215	>	return next = e;
3216	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3217	>	(n = t.length) <= (i = index) || i < 0)
3218	>	return next = null;
3219	>	if ((e = tabAt(t, index)) != null && e.hash < 0) {
3220	>	if (e instanceof ForwardingNode) {
3221	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3222	>	e = null;
3223	>	continue;
3224	>	}
3225	>	else if (e instanceof TreeBin)
3226	>	e = ((TreeBin<K,V>)e).first;
3227	>	else
3228	>	e = null;
3229	>	}
3230	>	if ((index += baseSize) >= n)
3231	>	index = ++baseIndex;    // visit upper slots if present
3232	>	}
3233	>	}
3234	>	}
3235	>
3236	>	/**
3237	>	* Base of key, value, and entry Iterators. Adds fields to
3238	>	* Traverser to support iterator.remove.
3239		*/
3240	<	public boolean contains(Object value) {
3241	<	return containsValue(value);
3240	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3241	>	final ConcurrentHashMap<K,V> map;
3242	>	Node<K,V> lastReturned;
3243	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3244	>	ConcurrentHashMap<K,V> map) {
3245	>	super(tab, size, index, limit);
3246	>	this.map = map;
3247	>	advance();
3248	>	}
3249	>
3250	>	public final boolean hasNext() { return next != null; }
3251	>	public final boolean hasMoreElements() { return next != null; }
3252	>
3253	>	public final void remove() {
3254	>	Node<K,V> p;
3255	>	if ((p = lastReturned) == null)
3256	>	throw new IllegalStateException();
3257	>	lastReturned = null;
3258	>	map.replaceNode(p.key, null, null);
3259	>	}
3260	>	}
3261	>
3262	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3263	>	implements Iterator<K>, Enumeration<K> {
3264	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3265	>	ConcurrentHashMap<K,V> map) {
3266	>	super(tab, index, size, limit, map);
3267	>	}
3268	>
3269	>	public final K next() {
3270	>	Node<K,V> p;
3271	>	if ((p = next) == null)
3272	>	throw new NoSuchElementException();
3273	>	K k = p.key;
3274	>	lastReturned = p;
3275	>	advance();
3276	>	return k;
3277	>	}
3278	>
3279	>	public final K nextElement() { return next(); }
3280	>	}
3281	>
3282	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3283	>	implements Iterator<V>, Enumeration<V> {
3284	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3285	>	ConcurrentHashMap<K,V> map) {
3286	>	super(tab, index, size, limit, map);
3287	>	}
3288	>
3289	>	public final V next() {
3290	>	Node<K,V> p;
3291	>	if ((p = next) == null)
3292	>	throw new NoSuchElementException();
3293	>	V v = p.val;
3294	>	lastReturned = p;
3295	>	advance();
3296	>	return v;
3297	>	}
3298	>
3299	>	public final V nextElement() { return next(); }
3300	>	}
3301	>
3302	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3303	>	implements Iterator<Map.Entry<K,V>> {
3304	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3305	>	ConcurrentHashMap<K,V> map) {
3306	>	super(tab, index, size, limit, map);
3307	>	}
3308	>
3309	>	public final Map.Entry<K,V> next() {
3310	>	Node<K,V> p;
3311	>	if ((p = next) == null)
3312	>	throw new NoSuchElementException();
3313	>	K k = p.key;
3314	>	V v = p.val;
3315	>	lastReturned = p;
3316	>	advance();
3317	>	return new MapEntry<K,V>(k, v, map);
3318	>	}
3319		}
3320
3321		/**
3322	<	* Maps the specified <tt>key</tt> to the specified
3323	<	* <tt>value</tt> in this table. Neither the key nor the
3324	<	* value can be <tt>null</tt>.
3322	>	* Exported Entry for EntryIterator
3323	>	*/
3324	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3325	>	final K key; // non-null
3326	>	V val;       // non-null
3327	>	final ConcurrentHashMap<K,V> map;
3328	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3329	>	this.key = key;
3330	>	this.val = val;
3331	>	this.map = map;
3332	>	}
3333	>	public K getKey()        { return key; }
3334	>	public V getValue()      { return val; }
3335	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3336	>	public String toString() { return key + "=" + val; }
3337	>
3338	>	public boolean equals(Object o) {
3339	>	Object k, v; Map.Entry<?,?> e;
3340	>	return ((o instanceof Map.Entry) &&
3341	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3342	>	(v = e.getValue()) != null &&
3343	>	(k == key || k.equals(key)) &&
3344	>	(v == val || v.equals(val)));
3345	>	}
3346	>
3347	>	/**
3348	>	* Sets our entry's value and writes through to the map. The
3349	>	* value to return is somewhat arbitrary here. Since we do not
3350	>	* necessarily track asynchronous changes, the most recent
3351	>	* "previous" value could be different from what we return (or
3352	>	* could even have been removed, in which case the put will
3353	>	* re-establish). We do not and cannot guarantee more.
3354	>	*/
3355	>	public V setValue(V value) {
3356	>	if (value == null) throw new NullPointerException();
3357	>	V v = val;
3358	>	val = value;
3359	>	map.put(key, value);
3360	>	return v;
3361	>	}
3362	>	}
3363	>
3364	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3365	>	implements Spliterator<K> {
3366	>	long est;               // size estimate
3367	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3368	>	long est) {
3369	>	super(tab, size, index, limit);
3370	>	this.est = est;
3371	>	}
3372	>
3373	>	public Spliterator<K> trySplit() {
3374	>	int i, f, h;
3375	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3376	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3377	>	f, est >>>= 1);
3378	>	}
3379	>
3380	>	public void forEachRemaining(Consumer<? super K> action) {
3381	>	if (action == null) throw new NullPointerException();
3382	>	for (Node<K,V> p; (p = advance()) != null;)
3383	>	action.accept(p.key);
3384	>	}
3385	>
3386	>	public boolean tryAdvance(Consumer<? super K> action) {
3387	>	if (action == null) throw new NullPointerException();
3388	>	Node<K,V> p;
3389	>	if ((p = advance()) == null)
3390	>	return false;
3391	>	action.accept(p.key);
3392	>	return true;
3393	>	}
3394	>
3395	>	public long estimateSize() { return est; }
3396	>
3397	>	public int characteristics() {
3398	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3399	>	Spliterator.NONNULL;
3400	>	}
3401	>	}
3402	>
3403	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3404	>	implements Spliterator<V> {
3405	>	long est;               // size estimate
3406	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3407	>	long est) {
3408	>	super(tab, size, index, limit);
3409	>	this.est = est;
3410	>	}
3411	>
3412	>	public Spliterator<V> trySplit() {
3413	>	int i, f, h;
3414	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3415	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3416	>	f, est >>>= 1);
3417	>	}
3418	>
3419	>	public void forEachRemaining(Consumer<? super V> action) {
3420	>	if (action == null) throw new NullPointerException();
3421	>	for (Node<K,V> p; (p = advance()) != null;)
3422	>	action.accept(p.val);
3423	>	}
3424	>
3425	>	public boolean tryAdvance(Consumer<? super V> action) {
3426	>	if (action == null) throw new NullPointerException();
3427	>	Node<K,V> p;
3428	>	if ((p = advance()) == null)
3429	>	return false;
3430	>	action.accept(p.val);
3431	>	return true;
3432	>	}
3433	>
3434	>	public long estimateSize() { return est; }
3435	>
3436	>	public int characteristics() {
3437	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3438	>	}
3439	>	}
3440	>
3441	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3442	>	implements Spliterator<Map.Entry<K,V>> {
3443	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3444	>	long est;               // size estimate
3445	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3446	>	long est, ConcurrentHashMap<K,V> map) {
3447	>	super(tab, size, index, limit);
3448	>	this.map = map;
3449	>	this.est = est;
3450	>	}
3451	>
3452	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3453	>	int i, f, h;
3454	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3455	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3456	>	f, est >>>= 1, map);
3457	>	}
3458	>
3459	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3460	>	if (action == null) throw new NullPointerException();
3461	>	for (Node<K,V> p; (p = advance()) != null; )
3462	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3463	>	}
3464	>
3465	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3466	>	if (action == null) throw new NullPointerException();
3467	>	Node<K,V> p;
3468	>	if ((p = advance()) == null)
3469	>	return false;
3470	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3471	>	return true;
3472	>	}
3473	>
3474	>	public long estimateSize() { return est; }
3475	>
3476	>	public int characteristics() {
3477	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3478	>	Spliterator.NONNULL;
3479	>	}
3480	>	}
3481	>
3482	>	// Parallel bulk operations
3483	>
3484	>	/**
3485	>	* Computes initial batch value for bulk tasks. The returned value
3486	>	* is approximately exp2 of the number of times (minus one) to
3487	>	* split task by two before executing leaf action. This value is
3488	>	* faster to compute and more convenient to use as a guide to
3489	>	* splitting than is the depth, since it is used while dividing by
3490	>	* two anyway.
3491	>	*/
3492	>	final int batchFor(long b) {
3493	>	long n;
3494	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3495	>	return 0;
3496	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3497	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3498	>	}
3499	>
3500	>	/**
3501	>	* Performs the given action for each (key, value).
3502		*
3503	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
3504	<	* with a key that is equal to the original key.
3503	>	* @param parallelismThreshold the (estimated) number of elements
3504	>	* needed for this operation to be executed in parallel
3505	>	* @param action the action
3506	>	* @since 1.8
3507	>	*/
3508	>	public void forEach(long parallelismThreshold,
3509	>	BiConsumer<? super K,? super V> action) {
3510	>	if (action == null) throw new NullPointerException();
3511	>	new ForEachMappingTask<K,V>
3512	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3513	>	action).invoke();
3514	>	}
3515	>
3516	>	/**
3517	>	* Performs the given action for each non-null transformation
3518	>	* of each (key, value).
3519		*
3520	<	* @param      key     the table key.
3521	<	* @param      value   the value.
3522	<	* @return     the previous value of the specified key in this table,
3523	<	*             or <tt>null</tt> if it did not have one.
3524	<	* @throws  NullPointerException  if the key or value is
3525	<	*               <tt>null</tt>.
3526	<	*/
3527	<	public V put(K key, V value) {
3528	<	if (value == null)
3520	>	* @param parallelismThreshold the (estimated) number of elements
3521	>	* needed for this operation to be executed in parallel
3522	>	* @param transformer a function returning the transformation
3523	>	* for an element, or null if there is no transformation (in
3524	>	* which case the action is not applied)
3525	>	* @param action the action
3526	>	* @param <U> the return type of the transformer
3527	>	* @since 1.8
3528	>	*/
3529	>	public <U> void forEach(long parallelismThreshold,
3530	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3531	>	Consumer<? super U> action) {
3532	>	if (transformer == null || action == null)
3533		throw new NullPointerException();
3534	<	int hash = hash(key);
3535	<	return segmentFor(hash).put(key, hash, value, false);
3534	>	new ForEachTransformedMappingTask<K,V,U>
3535	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3536	>	transformer, action).invoke();
3537		}
3538
3539		/**
3540	<	* If the specified key is not already associated
3541	<	* with a value, associate it with the given value.
3542	<	* This is equivalent to
3543	<	* <pre>
3544	<	*   if (!map.containsKey(key))
3545	<	*      return map.put(key, value);
3546	<	*   else
3547	<	*      return map.get(key);</pre>
3548	<	* except that the action is performed atomically.
3549	<	* @param key key with which the specified value is to be associated.
3550	<	* @param value value to be associated with the specified key.
3551	<	* @return previous value associated with specified key, or <tt>null</tt>
3552	<	*         if there was no mapping for key.
3553	<	* @throws NullPointerException if the specified key or value is
3554	<	*            <tt>null</tt>.
3555	<	*/
3556	<	public V putIfAbsent(K key, V value) {
3557	<	if (value == null)
3540	>	* Returns a non-null result from applying the given search
3541	>	* function on each (key, value), or null if none.  Upon
3542	>	* success, further element processing is suppressed and the
3543	>	* results of any other parallel invocations of the search
3544	>	* function are ignored.
3545	>	*
3546	>	* @param parallelismThreshold the (estimated) number of elements
3547	>	* needed for this operation to be executed in parallel
3548	>	* @param searchFunction a function returning a non-null
3549	>	* result on success, else null
3550	>	* @param <U> the return type of the search function
3551	>	* @return a non-null result from applying the given search
3552	>	* function on each (key, value), or null if none
3553	>	* @since 1.8
3554	>	*/
3555	>	public <U> U search(long parallelismThreshold,
3556	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3557	>	if (searchFunction == null) throw new NullPointerException();
3558	>	return new SearchMappingsTask<K,V,U>
3559	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3560	>	searchFunction, new AtomicReference<U>()).invoke();
3561	>	}
3562	>
3563	>	/**
3564	>	* Returns the result of accumulating the given transformation
3565	>	* of all (key, value) pairs using the given reducer to
3566	>	* combine values, or null if none.
3567	>	*
3568	>	* @param parallelismThreshold the (estimated) number of elements
3569	>	* needed for this operation to be executed in parallel
3570	>	* @param transformer a function returning the transformation
3571	>	* for an element, or null if there is no transformation (in
3572	>	* which case it is not combined)
3573	>	* @param reducer a commutative associative combining function
3574	>	* @param <U> the return type of the transformer
3575	>	* @return the result of accumulating the given transformation
3576	>	* of all (key, value) pairs
3577	>	* @since 1.8
3578	>	*/
3579	>	public <U> U reduce(long parallelismThreshold,
3580	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3581	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3582	>	if (transformer == null || reducer == null)
3583		throw new NullPointerException();
3584	<	int hash = hash(key);
3585	<	return segmentFor(hash).put(key, hash, value, true);
3584	>	return new MapReduceMappingsTask<K,V,U>
3585	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3586	>	null, transformer, reducer).invoke();
3587		}
3588
3589	+	/**
3590	+	* Returns the result of accumulating the given transformation
3591	+	* of all (key, value) pairs using the given reducer to
3592	+	* combine values, and the given basis as an identity value.
3593	+	*
3594	+	* @param parallelismThreshold the (estimated) number of elements
3595	+	* needed for this operation to be executed in parallel
3596	+	* @param transformer a function returning the transformation
3597	+	* for an element
3598	+	* @param basis the identity (initial default value) for the reduction
3599	+	* @param reducer a commutative associative combining function
3600	+	* @return the result of accumulating the given transformation
3601	+	* of all (key, value) pairs
3602	+	* @since 1.8
3603	+	*/
3604	+	public double reduceToDouble(long parallelismThreshold,
3605	+	ToDoubleBiFunction<? super K, ? super V> transformer,
3606	+	double basis,
3607	+	DoubleBinaryOperator reducer) {
3608	+	if (transformer == null || reducer == null)
3609	+	throw new NullPointerException();
3610	+	return new MapReduceMappingsToDoubleTask<K,V>
3611	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3612	+	null, transformer, basis, reducer).invoke();
3613	+	}
3614
3615		/**
3616	<	* Copies all of the mappings from the specified map to this one.
3616	>	* Returns the result of accumulating the given transformation
3617	>	* of all (key, value) pairs using the given reducer to
3618	>	* combine values, and the given basis as an identity value.
3619		*
3620	<	* These mappings replace any mappings that this map had for any of the
3621	<	* keys currently in the specified Map.
3620	>	* @param parallelismThreshold the (estimated) number of elements
3621	>	* needed for this operation to be executed in parallel
3622	>	* @param transformer a function returning the transformation
3623	>	* for an element
3624	>	* @param basis the identity (initial default value) for the reduction
3625	>	* @param reducer a commutative associative combining function
3626	>	* @return the result of accumulating the given transformation
3627	>	* of all (key, value) pairs
3628	>	* @since 1.8
3629	>	*/
3630	>	public long reduceToLong(long parallelismThreshold,
3631	>	ToLongBiFunction<? super K, ? super V> transformer,
3632	>	long basis,
3633	>	LongBinaryOperator reducer) {
3634	>	if (transformer == null || reducer == null)
3635	>	throw new NullPointerException();
3636	>	return new MapReduceMappingsToLongTask<K,V>
3637	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3638	>	null, transformer, basis, reducer).invoke();
3639	>	}
3640	>
3641	>	/**
3642	>	* Returns the result of accumulating the given transformation
3643	>	* of all (key, value) pairs using the given reducer to
3644	>	* combine values, and the given basis as an identity value.
3645		*
3646	<	* @param t Mappings to be stored in this map.
3647	<	*/
3648	<	public void putAll(Map<? extends K, ? extends V> t) {
3649	<	for (Iterator<? extends Map.Entry<? extends K, ? extends V>> it = (Iterator<? extends Map.Entry<? extends K, ? extends V>>) t.entrySet().iterator(); it.hasNext(); ) {
3650	<	Entry<? extends K, ? extends V> e = it.next();
3651	<	put(e.getKey(), e.getValue());
3652	<	}
3646	>	* @param parallelismThreshold the (estimated) number of elements
3647	>	* needed for this operation to be executed in parallel
3648	>	* @param transformer a function returning the transformation
3649	>	* for an element
3650	>	* @param basis the identity (initial default value) for the reduction
3651	>	* @param reducer a commutative associative combining function
3652	>	* @return the result of accumulating the given transformation
3653	>	* of all (key, value) pairs
3654	>	* @since 1.8
3655	>	*/
3656	>	public int reduceToInt(long parallelismThreshold,
3657	>	ToIntBiFunction<? super K, ? super V> transformer,
3658	>	int basis,
3659	>	IntBinaryOperator reducer) {
3660	>	if (transformer == null || reducer == null)
3661	>	throw new NullPointerException();
3662	>	return new MapReduceMappingsToIntTask<K,V>
3663	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3664	>	null, transformer, basis, reducer).invoke();
3665		}
3666
3667		/**
3668	<	* Removes the key (and its corresponding value) from this
923	<	* table. This method does nothing if the key is not in the table.
3668	>	* Performs the given action for each key.
3669		*
3670	<	* @param   key   the key that needs to be removed.
3671	<	* @return  the value to which the key had been mapped in this table,
3672	<	*          or <tt>null</tt> if the key did not have a mapping.
3673	<	* @throws  NullPointerException  if the key is
3674	<	*               <tt>null</tt>.
3675	<	*/
3676	<	public V remove(Object key) {
3677	<	int hash = hash(key);
3678	<	return segmentFor(hash).remove(key, hash, null);
3670	>	* @param parallelismThreshold the (estimated) number of elements
3671	>	* needed for this operation to be executed in parallel
3672	>	* @param action the action
3673	>	* @since 1.8
3674	>	*/
3675	>	public void forEachKey(long parallelismThreshold,
3676	>	Consumer<? super K> action) {
3677	>	if (action == null) throw new NullPointerException();
3678	>	new ForEachKeyTask<K,V>
3679	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3680	>	action).invoke();
3681		}
3682
3683		/**
3684	<	* Remove entry for key only if currently mapped to given value.
3685	<	* Acts as
3686	<	* <pre>
3687	<	*  if (map.get(key).equals(value)) {
3688	<	*     map.remove(key);
3689	<	*     return true;
3690	<	* } else return false;</pre>
3691	<	* except that the action is performed atomically.
3692	<	* @param key key with which the specified value is associated.
3693	<	* @param value value associated with the specified key.
3694	<	* @return true if the value was removed
3695	<	* @throws NullPointerException if the specified key is
3696	<	*            <tt>null</tt>.
3697	<	*/
3698	<	public boolean remove(Object key, Object value) {
3699	<	int hash = hash(key);
3700	<	return segmentFor(hash).remove(key, hash, value) != null;
3684	>	* Performs the given action for each non-null transformation
3685	>	* of each key.
3686	>	*
3687	>	* @param parallelismThreshold the (estimated) number of elements
3688	>	* needed for this operation to be executed in parallel
3689	>	* @param transformer a function returning the transformation
3690	>	* for an element, or null if there is no transformation (in
3691	>	* which case the action is not applied)
3692	>	* @param action the action
3693	>	* @param <U> the return type of the transformer
3694	>	* @since 1.8
3695	>	*/
3696	>	public <U> void forEachKey(long parallelismThreshold,
3697	>	Function<? super K, ? extends U> transformer,
3698	>	Consumer<? super U> action) {
3699	>	if (transformer == null || action == null)
3700	>	throw new NullPointerException();
3701	>	new ForEachTransformedKeyTask<K,V,U>
3702	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3703	>	transformer, action).invoke();
3704		}
3705
3706	+	/**
3707	+	* Returns a non-null result from applying the given search
3708	+	* function on each key, or null if none. Upon success,
3709	+	* further element processing is suppressed and the results of
3710	+	* any other parallel invocations of the search function are
3711	+	* ignored.
3712	+	*
3713	+	* @param parallelismThreshold the (estimated) number of elements
3714	+	* needed for this operation to be executed in parallel
3715	+	* @param searchFunction a function returning a non-null
3716	+	* result on success, else null
3717	+	* @param <U> the return type of the search function
3718	+	* @return a non-null result from applying the given search
3719	+	* function on each key, or null if none
3720	+	* @since 1.8
3721	+	*/
3722	+	public <U> U searchKeys(long parallelismThreshold,
3723	+	Function<? super K, ? extends U> searchFunction) {
3724	+	if (searchFunction == null) throw new NullPointerException();
3725	+	return new SearchKeysTask<K,V,U>
3726	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3727	+	searchFunction, new AtomicReference<U>()).invoke();
3728	+	}
3729
3730		/**
3731	<	* Replaces entry for key only if currently mapped to given value.
3732	<	* Acts as
3733	<	* <pre>
3734	<	*  if (map.get(key).equals(oldValue)) {
3735	<	*     map.put(key, newValue);
3736	<	*     return true;
3737	<	* } else return false;</pre>
3738	<	* except that the action is performed atomically.
3739	<	* @param key key with which the specified value is associated.
3740	<	* @param oldValue value expected to be associated with the specified key.
3741	<	* @param newValue value to be associated with the specified key.
3742	<	* @return true if the value was replaced
3743	<	* @throws NullPointerException if the specified key or values are
3744	<	* <tt>null</tt>.
3745	<	*/
3746	<	public boolean replace(K key, V oldValue, V newValue) {
3747	<	if (oldValue == null || newValue == null)
3731	>	* Returns the result of accumulating all keys using the given
3732	>	* reducer to combine values, or null if none.
3733	>	*
3734	>	* @param parallelismThreshold the (estimated) number of elements
3735	>	* needed for this operation to be executed in parallel
3736	>	* @param reducer a commutative associative combining function
3737	>	* @return the result of accumulating all keys using the given
3738	>	* reducer to combine values, or null if none
3739	>	* @since 1.8
3740	>	*/
3741	>	public K reduceKeys(long parallelismThreshold,
3742	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3743	>	if (reducer == null) throw new NullPointerException();
3744	>	return new ReduceKeysTask<K,V>
3745	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3746	>	null, reducer).invoke();
3747	>	}
3748	>
3749	>	/**
3750	>	* Returns the result of accumulating the given transformation
3751	>	* of all keys using the given reducer to combine values, or
3752	>	* null if none.
3753	>	*
3754	>	* @param parallelismThreshold the (estimated) number of elements
3755	>	* needed for this operation to be executed in parallel
3756	>	* @param transformer a function returning the transformation
3757	>	* for an element, or null if there is no transformation (in
3758	>	* which case it is not combined)
3759	>	* @param reducer a commutative associative combining function
3760	>	* @param <U> the return type of the transformer
3761	>	* @return the result of accumulating the given transformation
3762	>	* of all keys
3763	>	* @since 1.8
3764	>	*/
3765	>	public <U> U reduceKeys(long parallelismThreshold,
3766	>	Function<? super K, ? extends U> transformer,
3767	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3768	>	if (transformer == null || reducer == null)
3769		throw new NullPointerException();
3770	<	int hash = hash(key);
3771	<	return segmentFor(hash).replace(key, hash, oldValue, newValue);
3770	>	return new MapReduceKeysTask<K,V,U>
3771	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3772	>	null, transformer, reducer).invoke();
3773		}
3774
3775		/**
3776	<	* Replaces entry for key only if currently mapped to some value.
3777	<	* Acts as
3778	<	* <pre>
3779	<	*  if (map.containsKey(key)) {
3780	<	*     return map.put(key, value);
3781	<	* } else return null;</pre>
3782	<	* except that the action is performed atomically.
3783	<	* @param key key with which the specified value is associated.
3784	<	* @param value value to be associated with the specified key.
3785	<	* @return previous value associated with specified key, or <tt>null</tt>
3786	<	*         if there was no mapping for key.
3787	<	* @throws NullPointerException if the specified key or value is
3788	<	*            <tt>null</tt>.
3789	<	*/
3790	<	public V replace(K key, V value) {
3791	<	if (value == null)
3776	>	* Returns the result of accumulating the given transformation
3777	>	* of all keys using the given reducer to combine values, and
3778	>	* the given basis as an identity value.
3779	>	*
3780	>	* @param parallelismThreshold the (estimated) number of elements
3781	>	* needed for this operation to be executed in parallel
3782	>	* @param transformer a function returning the transformation
3783	>	* for an element
3784	>	* @param basis the identity (initial default value) for the reduction
3785	>	* @param reducer a commutative associative combining function
3786	>	* @return the result of accumulating the given transformation
3787	>	* of all keys
3788	>	* @since 1.8
3789	>	*/
3790	>	public double reduceKeysToDouble(long parallelismThreshold,
3791	>	ToDoubleFunction<? super K> transformer,
3792	>	double basis,
3793	>	DoubleBinaryOperator reducer) {
3794	>	if (transformer == null || reducer == null)
3795		throw new NullPointerException();
3796	<	int hash = hash(key);
3797	<	return segmentFor(hash).replace(key, hash, value);
3796	>	return new MapReduceKeysToDoubleTask<K,V>
3797	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3798	>	null, transformer, basis, reducer).invoke();
3799		}
3800
3801	+	/**
3802	+	* Returns the result of accumulating the given transformation
3803	+	* of all keys using the given reducer to combine values, and
3804	+	* the given basis as an identity value.
3805	+	*
3806	+	* @param parallelismThreshold the (estimated) number of elements
3807	+	* needed for this operation to be executed in parallel
3808	+	* @param transformer a function returning the transformation
3809	+	* for an element
3810	+	* @param basis the identity (initial default value) for the reduction
3811	+	* @param reducer a commutative associative combining function
3812	+	* @return the result of accumulating the given transformation
3813	+	* of all keys
3814	+	* @since 1.8
3815	+	*/
3816	+	public long reduceKeysToLong(long parallelismThreshold,
3817	+	ToLongFunction<? super K> transformer,
3818	+	long basis,
3819	+	LongBinaryOperator reducer) {
3820	+	if (transformer == null || reducer == null)
3821	+	throw new NullPointerException();
3822	+	return new MapReduceKeysToLongTask<K,V>
3823	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3824	+	null, transformer, basis, reducer).invoke();
3825	+	}
3826
3827		/**
3828	<	* Removes all mappings from this map.
3829	<	*/
3830	<	public void clear() {
3831	<	for (int i = 0; i < segments.length; ++i)
3832	<	segments[i].clear();
3828	>	* Returns the result of accumulating the given transformation
3829	>	* of all keys using the given reducer to combine values, and
3830	>	* the given basis as an identity value.
3831	>	*
3832	>	* @param parallelismThreshold the (estimated) number of elements
3833	>	* needed for this operation to be executed in parallel
3834	>	* @param transformer a function returning the transformation
3835	>	* for an element
3836	>	* @param basis the identity (initial default value) for the reduction
3837	>	* @param reducer a commutative associative combining function
3838	>	* @return the result of accumulating the given transformation
3839	>	* of all keys
3840	>	* @since 1.8
3841	>	*/
3842	>	public int reduceKeysToInt(long parallelismThreshold,
3843	>	ToIntFunction<? super K> transformer,
3844	>	int basis,
3845	>	IntBinaryOperator reducer) {
3846	>	if (transformer == null || reducer == null)
3847	>	throw new NullPointerException();
3848	>	return new MapReduceKeysToIntTask<K,V>
3849	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3850	>	null, transformer, basis, reducer).invoke();
3851		}
3852
3853		/**
3854	<	* Returns a set view of the keys contained in this map.  The set is
1013	<	* backed by the map, so changes to the map are reflected in the set, and
1014	<	* vice-versa.  The set supports element removal, which removes the
1015	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
1016	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
1017	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
1018	<	* <tt>addAll</tt> operations.
1019	<	* The view's returned <tt>iterator</tt> is a "weakly consistent" iterator that
1020	<	* will never throw {@link java.util.ConcurrentModificationException},
1021	<	* and guarantees to traverse elements as they existed upon
1022	<	* construction of the iterator, and may (but is not guaranteed to)
1023	<	* reflect any modifications subsequent to construction.
3854	>	* Performs the given action for each value.
3855		*
3856	<	* @return a set view of the keys contained in this map.
3857	<	*/
3858	<	public Set<K> keySet() {
3859	<	Set<K> ks = keySet;
3860	<	return (ks != null) ? ks : (keySet = new KeySet());
3856	>	* @param parallelismThreshold the (estimated) number of elements
3857	>	* needed for this operation to be executed in parallel
3858	>	* @param action the action
3859	>	* @since 1.8
3860	>	*/
3861	>	public void forEachValue(long parallelismThreshold,
3862	>	Consumer<? super V> action) {
3863	>	if (action == null)
3864	>	throw new NullPointerException();
3865	>	new ForEachValueTask<K,V>
3866	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3867	>	action).invoke();
3868		}
3869
3870	+	/**
3871	+	* Performs the given action for each non-null transformation
3872	+	* of each value.
3873	+	*
3874	+	* @param parallelismThreshold the (estimated) number of elements
3875	+	* needed for this operation to be executed in parallel
3876	+	* @param transformer a function returning the transformation
3877	+	* for an element, or null if there is no transformation (in
3878	+	* which case the action is not applied)
3879	+	* @param action the action
3880	+	* @param <U> the return type of the transformer
3881	+	* @since 1.8
3882	+	*/
3883	+	public <U> void forEachValue(long parallelismThreshold,
3884	+	Function<? super V, ? extends U> transformer,
3885	+	Consumer<? super U> action) {
3886	+	if (transformer == null || action == null)
3887	+	throw new NullPointerException();
3888	+	new ForEachTransformedValueTask<K,V,U>
3889	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3890	+	transformer, action).invoke();
3891	+	}
3892
3893		/**
3894	<	* Returns a collection view of the values contained in this map.  The
3895	<	* collection is backed by the map, so changes to the map are reflected in
3896	<	* the collection, and vice-versa.  The collection supports element
3897	<	* removal, which removes the corresponding mapping from this map, via the
3898	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
1039	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
1040	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
1041	<	* The view's returned <tt>iterator</tt> is a "weakly consistent" iterator that
1042	<	* will never throw {@link java.util.ConcurrentModificationException},
1043	<	* and guarantees to traverse elements as they existed upon
1044	<	* construction of the iterator, and may (but is not guaranteed to)
1045	<	* reflect any modifications subsequent to construction.
3894	>	* Returns a non-null result from applying the given search
3895	>	* function on each value, or null if none.  Upon success,
3896	>	* further element processing is suppressed and the results of
3897	>	* any other parallel invocations of the search function are
3898	>	* ignored.
3899		*
3900	<	* @return a collection view of the values contained in this map.
3901	<	*/
3902	<	public Collection<V> values() {
3903	<	Collection<V> vs = values;
3904	<	return (vs != null) ? vs : (values = new Values());
3900	>	* @param parallelismThreshold the (estimated) number of elements
3901	>	* needed for this operation to be executed in parallel
3902	>	* @param searchFunction a function returning a non-null
3903	>	* result on success, else null
3904	>	* @param <U> the return type of the search function
3905	>	* @return a non-null result from applying the given search
3906	>	* function on each value, or null if none
3907	>	* @since 1.8
3908	>	*/
3909	>	public <U> U searchValues(long parallelismThreshold,
3910	>	Function<? super V, ? extends U> searchFunction) {
3911	>	if (searchFunction == null) throw new NullPointerException();
3912	>	return new SearchValuesTask<K,V,U>
3913	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3914	>	searchFunction, new AtomicReference<U>()).invoke();
3915		}
3916
3917	+	/**
3918	+	* Returns the result of accumulating all values using the
3919	+	* given reducer to combine values, or null if none.
3920	+	*
3921	+	* @param parallelismThreshold the (estimated) number of elements
3922	+	* needed for this operation to be executed in parallel
3923	+	* @param reducer a commutative associative combining function
3924	+	* @return the result of accumulating all values
3925	+	* @since 1.8
3926	+	*/
3927	+	public V reduceValues(long parallelismThreshold,
3928	+	BiFunction<? super V, ? super V, ? extends V> reducer) {
3929	+	if (reducer == null) throw new NullPointerException();
3930	+	return new ReduceValuesTask<K,V>
3931	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3932	+	null, reducer).invoke();
3933	+	}
3934
3935		/**
3936	<	* Returns a collection view of the mappings contained in this map.  Each
3937	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
3938	<	* collection is backed by the map, so changes to the map are reflected in
1059	<	* the collection, and vice-versa.  The collection supports element
1060	<	* removal, which removes the corresponding mapping from the map, via the
1061	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
1062	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
1063	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
1064	<	* The view's returned <tt>iterator</tt> is a "weakly consistent" iterator that
1065	<	* will never throw {@link java.util.ConcurrentModificationException},
1066	<	* and guarantees to traverse elements as they existed upon
1067	<	* construction of the iterator, and may (but is not guaranteed to)
1068	<	* reflect any modifications subsequent to construction.
3936	>	* Returns the result of accumulating the given transformation
3937	>	* of all values using the given reducer to combine values, or
3938	>	* null if none.
3939		*
3940	<	* @return a collection view of the mappings contained in this map.
3941	<	*/
3942	<	public Set<Map.Entry<K,V>> entrySet() {
3943	<	Set<Map.Entry<K,V>> es = entrySet;
3944	<	return (es != null) ? es : (entrySet = (Set<Map.Entry<K,V>>) (Set) new EntrySet());
3940	>	* @param parallelismThreshold the (estimated) number of elements
3941	>	* needed for this operation to be executed in parallel
3942	>	* @param transformer a function returning the transformation
3943	>	* for an element, or null if there is no transformation (in
3944	>	* which case it is not combined)
3945	>	* @param reducer a commutative associative combining function
3946	>	* @param <U> the return type of the transformer
3947	>	* @return the result of accumulating the given transformation
3948	>	* of all values
3949	>	* @since 1.8
3950	>	*/
3951	>	public <U> U reduceValues(long parallelismThreshold,
3952	>	Function<? super V, ? extends U> transformer,
3953	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3954	>	if (transformer == null || reducer == null)
3955	>	throw new NullPointerException();
3956	>	return new MapReduceValuesTask<K,V,U>
3957	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3958	>	null, transformer, reducer).invoke();
3959		}
3960
3961	+	/**
3962	+	* Returns the result of accumulating the given transformation
3963	+	* of all values using the given reducer to combine values,
3964	+	* and the given basis as an identity value.
3965	+	*
3966	+	* @param parallelismThreshold the (estimated) number of elements
3967	+	* needed for this operation to be executed in parallel
3968	+	* @param transformer a function returning the transformation
3969	+	* for an element
3970	+	* @param basis the identity (initial default value) for the reduction
3971	+	* @param reducer a commutative associative combining function
3972	+	* @return the result of accumulating the given transformation
3973	+	* of all values
3974	+	* @since 1.8
3975	+	*/
3976	+	public double reduceValuesToDouble(long parallelismThreshold,
3977	+	ToDoubleFunction<? super V> transformer,
3978	+	double basis,
3979	+	DoubleBinaryOperator reducer) {
3980	+	if (transformer == null || reducer == null)
3981	+	throw new NullPointerException();
3982	+	return new MapReduceValuesToDoubleTask<K,V>
3983	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3984	+	null, transformer, basis, reducer).invoke();
3985	+	}
3986
3987		/**
3988	<	* Returns an enumeration of the keys in this table.
3988	>	* Returns the result of accumulating the given transformation
3989	>	* of all values using the given reducer to combine values,
3990	>	* and the given basis as an identity value.
3991		*
3992	<	* @return  an enumeration of the keys in this table.
3993	<	* @see     #keySet
3994	<	*/
3995	<	public Enumeration<K> keys() {
3996	<	return new KeyIterator();
3992	>	* @param parallelismThreshold the (estimated) number of elements
3993	>	* needed for this operation to be executed in parallel
3994	>	* @param transformer a function returning the transformation
3995	>	* for an element
3996	>	* @param basis the identity (initial default value) for the reduction
3997	>	* @param reducer a commutative associative combining function
3998	>	* @return the result of accumulating the given transformation
3999	>	* of all values
4000	>	* @since 1.8
4001	>	*/
4002	>	public long reduceValuesToLong(long parallelismThreshold,
4003	>	ToLongFunction<? super V> transformer,
4004	>	long basis,
4005	>	LongBinaryOperator reducer) {
4006	>	if (transformer == null || reducer == null)
4007	>	throw new NullPointerException();
4008	>	return new MapReduceValuesToLongTask<K,V>
4009	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4010	>	null, transformer, basis, reducer).invoke();
4011		}
4012
4013		/**
4014	<	* Returns an enumeration of the values in this table.
4014	>	* Returns the result of accumulating the given transformation
4015	>	* of all values using the given reducer to combine values,
4016	>	* and the given basis as an identity value.
4017		*
4018	<	* @return  an enumeration of the values in this table.
4019	<	* @see     #values
4020	<	*/
4021	<	public Enumeration<V> elements() {
4022	<	return new ValueIterator();
4018	>	* @param parallelismThreshold the (estimated) number of elements
4019	>	* needed for this operation to be executed in parallel
4020	>	* @param transformer a function returning the transformation
4021	>	* for an element
4022	>	* @param basis the identity (initial default value) for the reduction
4023	>	* @param reducer a commutative associative combining function
4024	>	* @return the result of accumulating the given transformation
4025	>	* of all values
4026	>	* @since 1.8
4027	>	*/
4028	>	public int reduceValuesToInt(long parallelismThreshold,
4029	>	ToIntFunction<? super V> transformer,
4030	>	int basis,
4031	>	IntBinaryOperator reducer) {
4032	>	if (transformer == null || reducer == null)
4033	>	throw new NullPointerException();
4034	>	return new MapReduceValuesToIntTask<K,V>
4035	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4036	>	null, transformer, basis, reducer).invoke();
4037		}
4038
4039	<	/* ---------------- Iterator Support -------------- */
4039	>	/**
4040	>	* Performs the given action for each entry.
4041	>	*
4042	>	* @param parallelismThreshold the (estimated) number of elements
4043	>	* needed for this operation to be executed in parallel
4044	>	* @param action the action
4045	>	* @since 1.8
4046	>	*/
4047	>	public void forEachEntry(long parallelismThreshold,
4048	>	Consumer<? super Map.Entry<K,V>> action) {
4049	>	if (action == null) throw new NullPointerException();
4050	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4051	>	action).invoke();
4052	>	}
4053
4054	<	abstract class HashIterator {
4055	<	int nextSegmentIndex;
4056	<	int nextTableIndex;
4057	<	HashEntry[] currentTable;
4058	<	HashEntry<K, V> nextEntry;
4059	<	HashEntry<K, V> lastReturned;
4054	>	/**
4055	>	* Performs the given action for each non-null transformation
4056	>	* of each entry.
4057	>	*
4058	>	* @param parallelismThreshold the (estimated) number of elements
4059	>	* needed for this operation to be executed in parallel
4060	>	* @param transformer a function returning the transformation
4061	>	* for an element, or null if there is no transformation (in
4062	>	* which case the action is not applied)
4063	>	* @param action the action
4064	>	* @param <U> the return type of the transformer
4065	>	* @since 1.8
4066	>	*/
4067	>	public <U> void forEachEntry(long parallelismThreshold,
4068	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4069	>	Consumer<? super U> action) {
4070	>	if (transformer == null || action == null)
4071	>	throw new NullPointerException();
4072	>	new ForEachTransformedEntryTask<K,V,U>
4073	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4074	>	transformer, action).invoke();
4075	>	}
4076
4077	<	HashIterator() {
4078	<	nextSegmentIndex = segments.length - 1;
4079	<	nextTableIndex = -1;
4080	<	advance();
4081	<	}
4077	>	/**
4078	>	* Returns a non-null result from applying the given search
4079	>	* function on each entry, or null if none.  Upon success,
4080	>	* further element processing is suppressed and the results of
4081	>	* any other parallel invocations of the search function are
4082	>	* ignored.
4083	>	*
4084	>	* @param parallelismThreshold the (estimated) number of elements
4085	>	* needed for this operation to be executed in parallel
4086	>	* @param searchFunction a function returning a non-null
4087	>	* result on success, else null
4088	>	* @param <U> the return type of the search function
4089	>	* @return a non-null result from applying the given search
4090	>	* function on each entry, or null if none
4091	>	* @since 1.8
4092	>	*/
4093	>	public <U> U searchEntries(long parallelismThreshold,
4094	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4095	>	if (searchFunction == null) throw new NullPointerException();
4096	>	return new SearchEntriesTask<K,V,U>
4097	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4098	>	searchFunction, new AtomicReference<U>()).invoke();
4099	>	}
4100
4101	<	public boolean hasMoreElements() { return hasNext(); }
4101	>	/**
4102	>	* Returns the result of accumulating all entries using the
4103	>	* given reducer to combine values, or null if none.
4104	>	*
4105	>	* @param parallelismThreshold the (estimated) number of elements
4106	>	* needed for this operation to be executed in parallel
4107	>	* @param reducer a commutative associative combining function
4108	>	* @return the result of accumulating all entries
4109	>	* @since 1.8
4110	>	*/
4111	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4112	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4113	>	if (reducer == null) throw new NullPointerException();
4114	>	return new ReduceEntriesTask<K,V>
4115	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4116	>	null, reducer).invoke();
4117	>	}
4118
4119	<	final void advance() {
4120	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
4121	<	return;
4119	>	/**
4120	>	* Returns the result of accumulating the given transformation
4121	>	* of all entries using the given reducer to combine values,
4122	>	* or null if none.
4123	>	*
4124	>	* @param parallelismThreshold the (estimated) number of elements
4125	>	* needed for this operation to be executed in parallel
4126	>	* @param transformer a function returning the transformation
4127	>	* for an element, or null if there is no transformation (in
4128	>	* which case it is not combined)
4129	>	* @param reducer a commutative associative combining function
4130	>	* @param <U> the return type of the transformer
4131	>	* @return the result of accumulating the given transformation
4132	>	* of all entries
4133	>	* @since 1.8
4134	>	*/
4135	>	public <U> U reduceEntries(long parallelismThreshold,
4136	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4137	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4138	>	if (transformer == null || reducer == null)
4139	>	throw new NullPointerException();
4140	>	return new MapReduceEntriesTask<K,V,U>
4141	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4142	>	null, transformer, reducer).invoke();
4143	>	}
4144
4145	<	while (nextTableIndex >= 0) {
4146	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[nextTableIndex--]) != null)
4147	<	return;
4145	>	/**
4146	>	* Returns the result of accumulating the given transformation
4147	>	* of all entries using the given reducer to combine values,
4148	>	* and the given basis as an identity value.
4149	>	*
4150	>	* @param parallelismThreshold the (estimated) number of elements
4151	>	* needed for this operation to be executed in parallel
4152	>	* @param transformer a function returning the transformation
4153	>	* for an element
4154	>	* @param basis the identity (initial default value) for the reduction
4155	>	* @param reducer a commutative associative combining function
4156	>	* @return the result of accumulating the given transformation
4157	>	* of all entries
4158	>	* @since 1.8
4159	>	*/
4160	>	public double reduceEntriesToDouble(long parallelismThreshold,
4161	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4162	>	double basis,
4163	>	DoubleBinaryOperator reducer) {
4164	>	if (transformer == null || reducer == null)
4165	>	throw new NullPointerException();
4166	>	return new MapReduceEntriesToDoubleTask<K,V>
4167	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4168	>	null, transformer, basis, reducer).invoke();
4169	>	}
4170	>
4171	>	/**
4172	>	* Returns the result of accumulating the given transformation
4173	>	* of all entries using the given reducer to combine values,
4174	>	* and the given basis as an identity value.
4175	>	*
4176	>	* @param parallelismThreshold the (estimated) number of elements
4177	>	* needed for this operation to be executed in parallel
4178	>	* @param transformer a function returning the transformation
4179	>	* for an element
4180	>	* @param basis the identity (initial default value) for the reduction
4181	>	* @param reducer a commutative associative combining function
4182	>	* @return the result of accumulating the given transformation
4183	>	* of all entries
4184	>	* @since 1.8
4185	>	*/
4186	>	public long reduceEntriesToLong(long parallelismThreshold,
4187	>	ToLongFunction<Map.Entry<K,V>> transformer,
4188	>	long basis,
4189	>	LongBinaryOperator reducer) {
4190	>	if (transformer == null || reducer == null)
4191	>	throw new NullPointerException();
4192	>	return new MapReduceEntriesToLongTask<K,V>
4193	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4194	>	null, transformer, basis, reducer).invoke();
4195	>	}
4196	>
4197	>	/**
4198	>	* Returns the result of accumulating the given transformation
4199	>	* of all entries using the given reducer to combine values,
4200	>	* and the given basis as an identity value.
4201	>	*
4202	>	* @param parallelismThreshold the (estimated) number of elements
4203	>	* needed for this operation to be executed in parallel
4204	>	* @param transformer a function returning the transformation
4205	>	* for an element
4206	>	* @param basis the identity (initial default value) for the reduction
4207	>	* @param reducer a commutative associative combining function
4208	>	* @return the result of accumulating the given transformation
4209	>	* of all entries
4210	>	* @since 1.8
4211	>	*/
4212	>	public int reduceEntriesToInt(long parallelismThreshold,
4213	>	ToIntFunction<Map.Entry<K,V>> transformer,
4214	>	int basis,
4215	>	IntBinaryOperator reducer) {
4216	>	if (transformer == null || reducer == null)
4217	>	throw new NullPointerException();
4218	>	return new MapReduceEntriesToIntTask<K,V>
4219	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4220	>	null, transformer, basis, reducer).invoke();
4221	>	}
4222	>
4223	>
4224	>	/* ----------------Views -------------- */
4225	>
4226	>	/**
4227	>	* Base class for views.
4228	>	*/
4229	>	abstract static class CollectionView<K,V,E>
4230	>	implements Collection<E>, java.io.Serializable {
4231	>	private static final long serialVersionUID = 7249069246763182397L;
4232	>	final ConcurrentHashMap<K,V> map;
4233	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4234	>
4235	>	/**
4236	>	* Returns the map backing this view.
4237	>	*
4238	>	* @return the map backing this view
4239	>	*/
4240	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4241	>
4242	>	/**
4243	>	* Removes all of the elements from this view, by removing all
4244	>	* the mappings from the map backing this view.
4245	>	*/
4246	>	public final void clear()      { map.clear(); }
4247	>	public final int size()        { return map.size(); }
4248	>	public final boolean isEmpty() { return map.isEmpty(); }
4249	>
4250	>	// implementations below rely on concrete classes supplying these
4251	>	// abstract methods
4252	>	/**
4253	>	* Returns a "weakly consistent" iterator that will never
4254	>	* throw {@link ConcurrentModificationException}, and
4255	>	* guarantees to traverse elements as they existed upon
4256	>	* construction of the iterator, and may (but is not
4257	>	* guaranteed to) reflect any modifications subsequent to
4258	>	* construction.
4259	>	*/
4260	>	public abstract Iterator<E> iterator();
4261	>	public abstract boolean contains(Object o);
4262	>	public abstract boolean remove(Object o);
4263	>
4264	>	private static final String oomeMsg = "Required array size too large";
4265	>
4266	>	public final Object[] toArray() {
4267	>	long sz = map.mappingCount();
4268	>	if (sz > MAX_ARRAY_SIZE)
4269	>	throw new OutOfMemoryError(oomeMsg);
4270	>	int n = (int)sz;
4271	>	Object[] r = new Object[n];
4272	>	int i = 0;
4273	>	for (E e : this) {
4274	>	if (i == n) {
4275	>	if (n >= MAX_ARRAY_SIZE)
4276	>	throw new OutOfMemoryError(oomeMsg);
4277	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4278	>	n = MAX_ARRAY_SIZE;
4279	>	else
4280	>	n += (n >>> 1) + 1;
4281	>	r = Arrays.copyOf(r, n);
4282	>	}
4283	>	r[i++] = e;
4284		}
4285	+	return (i == n) ? r : Arrays.copyOf(r, i);
4286	+	}
4287
4288	<	while (nextSegmentIndex >= 0) {
4289	<	Segment<K,V> seg = (Segment<K,V>)segments[nextSegmentIndex--];
4290	<	if (seg.count != 0) {
4291	<	currentTable = seg.table;
4292	<	for (int j = currentTable.length - 1; j >= 0; --j) {
4293	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[j]) != null) {
4294	<	nextTableIndex = j - 1;
4295	<	return;
4296	<	}
4297	<	}
4288	>	@SuppressWarnings("unchecked")
4289	>	public final <T> T[] toArray(T[] a) {
4290	>	long sz = map.mappingCount();
4291	>	if (sz > MAX_ARRAY_SIZE)
4292	>	throw new OutOfMemoryError(oomeMsg);
4293	>	int m = (int)sz;
4294	>	T[] r = (a.length >= m) ? a :
4295	>	(T[])java.lang.reflect.Array
4296	>	.newInstance(a.getClass().getComponentType(), m);
4297	>	int n = r.length;
4298	>	int i = 0;
4299	>	for (E e : this) {
4300	>	if (i == n) {
4301	>	if (n >= MAX_ARRAY_SIZE)
4302	>	throw new OutOfMemoryError(oomeMsg);
4303	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4304	>	n = MAX_ARRAY_SIZE;
4305	>	else
4306	>	n += (n >>> 1) + 1;
4307	>	r = Arrays.copyOf(r, n);
4308	>	}
4309	>	r[i++] = (T)e;
4310	>	}
4311	>	if (a == r && i < n) {
4312	>	r[i] = null; // null-terminate
4313	>	return r;
4314	>	}
4315	>	return (i == n) ? r : Arrays.copyOf(r, i);
4316	>	}
4317	>
4318	>	/**
4319	>	* Returns a string representation of this collection.
4320	>	* The string representation consists of the string representations
4321	>	* of the collection's elements in the order they are returned by
4322	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4323	>	* Adjacent elements are separated by the characters {@code ", "}
4324	>	* (comma and space).  Elements are converted to strings as by
4325	>	* {@link String#valueOf(Object)}.
4326	>	*
4327	>	* @return a string representation of this collection
4328	>	*/
4329	>	public final String toString() {
4330	>	StringBuilder sb = new StringBuilder();
4331	>	sb.append('[');
4332	>	Iterator<E> it = iterator();
4333	>	if (it.hasNext()) {
4334	>	for (;;) {
4335	>	Object e = it.next();
4336	>	sb.append(e == this ? "(this Collection)" : e);
4337	>	if (!it.hasNext())
4338	>	break;
4339	>	sb.append(',').append(' ');
4340		}
4341		}
4342	+	return sb.append(']').toString();
4343		}
4344
4345	<	public boolean hasNext() { return nextEntry != null; }
4345	>	public final boolean containsAll(Collection<?> c) {
4346	>	if (c != this) {
4347	>	for (Object e : c) {
4348	>	if (e == null || !contains(e))
4349	>	return false;
4350	>	}
4351	>	}
4352	>	return true;
4353	>	}
4354
4355	<	HashEntry<K,V> nextEntry() {
4356	<	if (nextEntry == null)
4357	<	throw new NoSuchElementException();
4358	<	lastReturned = nextEntry;
4359	<	advance();
4360	<	return lastReturned;
4355	>	public final boolean removeAll(Collection<?> c) {
4356	>	boolean modified = false;
4357	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4358	>	if (c.contains(it.next())) {
4359	>	it.remove();
4360	>	modified = true;
4361	>	}
4362	>	}
4363	>	return modified;
4364		}
4365
4366	<	public void remove() {
4367	<	if (lastReturned == null)
4368	<	throw new IllegalStateException();
4369	<	ConcurrentHashMap.this.remove(lastReturned.key);
4370	<	lastReturned = null;
4366	>	public final boolean retainAll(Collection<?> c) {
4367	>	boolean modified = false;
4368	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4369	>	if (!c.contains(it.next())) {
4370	>	it.remove();
4371	>	modified = true;
4372	>	}
4373	>	}
4374	>	return modified;
4375		}
1154	–	}
4376
1156	–	final class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
1157	–	public K next() { return super.nextEntry().key; }
1158	–	public K nextElement() { return super.nextEntry().key; }
4377		}
4378
4379	<	final class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
4380	<	public V next() { return super.nextEntry().value; }
4381	<	public V nextElement() { return super.nextEntry().value; }
4379	>	/**
4380	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4381	>	* which additions may optionally be enabled by mapping to a
4382	>	* common value.  This class cannot be directly instantiated.
4383	>	* See {@link #keySet() keySet()},
4384	>	* {@link #keySet(Object) keySet(V)},
4385	>	* {@link #newKeySet() newKeySet()},
4386	>	* {@link #newKeySet(int) newKeySet(int)}.
4387	>	*
4388	>	* @since 1.8
4389	>	*/
4390	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4391	>	implements Set<K>, java.io.Serializable {
4392	>	private static final long serialVersionUID = 7249069246763182397L;
4393	>	private final V value;
4394	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4395	>	super(map);
4396	>	this.value = value;
4397	>	}
4398	>
4399	>	/**
4400	>	* Returns the default mapped value for additions,
4401	>	* or {@code null} if additions are not supported.
4402	>	*
4403	>	* @return the default mapped value for additions, or {@code null}
4404	>	* if not supported
4405	>	*/
4406	>	public V getMappedValue() { return value; }
4407	>
4408	>	/**
4409	>	* {@inheritDoc}
4410	>	* @throws NullPointerException if the specified key is null
4411	>	*/
4412	>	public boolean contains(Object o) { return map.containsKey(o); }
4413	>
4414	>	/**
4415	>	* Removes the key from this map view, by removing the key (and its
4416	>	* corresponding value) from the backing map.  This method does
4417	>	* nothing if the key is not in the map.
4418	>	*
4419	>	* @param  o the key to be removed from the backing map
4420	>	* @return {@code true} if the backing map contained the specified key
4421	>	* @throws NullPointerException if the specified key is null
4422	>	*/
4423	>	public boolean remove(Object o) { return map.remove(o) != null; }
4424	>
4425	>	/**
4426	>	* @return an iterator over the keys of the backing map
4427	>	*/
4428	>	public Iterator<K> iterator() {
4429	>	Node<K,V>[] t;
4430	>	ConcurrentHashMap<K,V> m = map;
4431	>	int f = (t = m.table) == null ? 0 : t.length;
4432	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4433	>	}
4434	>
4435	>	/**
4436	>	* Adds the specified key to this set view by mapping the key to
4437	>	* the default mapped value in the backing map, if defined.
4438	>	*
4439	>	* @param e key to be added
4440	>	* @return {@code true} if this set changed as a result of the call
4441	>	* @throws NullPointerException if the specified key is null
4442	>	* @throws UnsupportedOperationException if no default mapped value
4443	>	* for additions was provided
4444	>	*/
4445	>	public boolean add(K e) {
4446	>	V v;
4447	>	if ((v = value) == null)
4448	>	throw new UnsupportedOperationException();
4449	>	return map.putVal(e, v, true) == null;
4450	>	}
4451	>
4452	>	/**
4453	>	* Adds all of the elements in the specified collection to this set,
4454	>	* as if by calling {@link #add} on each one.
4455	>	*
4456	>	* @param c the elements to be inserted into this set
4457	>	* @return {@code true} if this set changed as a result of the call
4458	>	* @throws NullPointerException if the collection or any of its
4459	>	* elements are {@code null}
4460	>	* @throws UnsupportedOperationException if no default mapped value
4461	>	* for additions was provided
4462	>	*/
4463	>	public boolean addAll(Collection<? extends K> c) {
4464	>	boolean added = false;
4465	>	V v;
4466	>	if ((v = value) == null)
4467	>	throw new UnsupportedOperationException();
4468	>	for (K e : c) {
4469	>	if (map.putVal(e, v, true) == null)
4470	>	added = true;
4471	>	}
4472	>	return added;
4473	>	}
4474	>
4475	>	public int hashCode() {
4476	>	int h = 0;
4477	>	for (K e : this)
4478	>	h += e.hashCode();
4479	>	return h;
4480	>	}
4481	>
4482	>	public boolean equals(Object o) {
4483	>	Set<?> c;
4484	>	return ((o instanceof Set) &&
4485	>	((c = (Set<?>)o) == this ||
4486	>	(containsAll(c) && c.containsAll(this))));
4487	>	}
4488	>
4489	>	public Spliterator<K> spliterator() {
4490	>	Node<K,V>[] t;
4491	>	ConcurrentHashMap<K,V> m = map;
4492	>	long n = m.sumCount();
4493	>	int f = (t = m.table) == null ? 0 : t.length;
4494	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4495	>	}
4496	>
4497	>	public void forEach(Consumer<? super K> action) {
4498	>	if (action == null) throw new NullPointerException();
4499	>	Node<K,V>[] t;
4500	>	if ((t = map.table) != null) {
4501	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4502	>	for (Node<K,V> p; (p = it.advance()) != null; )
4503	>	action.accept(p.key);
4504	>	}
4505	>	}
4506		}
4507
4508	+	/**
4509	+	* A view of a ConcurrentHashMap as a {@link Collection} of
4510	+	* values, in which additions are disabled. This class cannot be
4511	+	* directly instantiated. See {@link #values()}.
4512	+	*/
4513	+	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4514	+	implements Collection<V>, java.io.Serializable {
4515	+	private static final long serialVersionUID = 2249069246763182397L;
4516	+	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4517	+	public final boolean contains(Object o) {
4518	+	return map.containsValue(o);
4519	+	}
4520
4521	+	public final boolean remove(Object o) {
4522	+	if (o != null) {
4523	+	for (Iterator<V> it = iterator(); it.hasNext();) {
4524	+	if (o.equals(it.next())) {
4525	+	it.remove();
4526	+	return true;
4527	+	}
4528	+	}
4529	+	}
4530	+	return false;
4531	+	}
4532	+
4533	+	public final Iterator<V> iterator() {
4534	+	ConcurrentHashMap<K,V> m = map;
4535	+	Node<K,V>[] t;
4536	+	int f = (t = m.table) == null ? 0 : t.length;
4537	+	return new ValueIterator<K,V>(t, f, 0, f, m);
4538	+	}
4539	+
4540	+	public final boolean add(V e) {
4541	+	throw new UnsupportedOperationException();
4542	+	}
4543	+	public final boolean addAll(Collection<? extends V> c) {
4544	+	throw new UnsupportedOperationException();
4545	+	}
4546	+
4547	+	public Spliterator<V> spliterator() {
4548	+	Node<K,V>[] t;
4549	+	ConcurrentHashMap<K,V> m = map;
4550	+	long n = m.sumCount();
4551	+	int f = (t = m.table) == null ? 0 : t.length;
4552	+	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4553	+	}
4554	+
4555	+	public void forEach(Consumer<? super V> action) {
4556	+	if (action == null) throw new NullPointerException();
4557	+	Node<K,V>[] t;
4558	+	if ((t = map.table) != null) {
4559	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4560	+	for (Node<K,V> p; (p = it.advance()) != null; )
4561	+	action.accept(p.val);
4562	+	}
4563	+	}
4564	+	}
4565
4566		/**
4567	<	* Entry iterator. Exported Entry objects must write-through
4568	<	* changes in setValue, even if the nodes have been cloned. So we
4569	<	* cannot return internal HashEntry objects. Instead, the iterator
1172	<	* itself acts as a forwarding pseudo-entry.
4567	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4568	>	* entries.  This class cannot be directly instantiated. See
4569	>	* {@link #entrySet()}.
4570		*/
4571	<	final class EntryIterator extends HashIterator implements Map.Entry<K,V>, Iterator<Entry<K,V>> {
4572	<	public Map.Entry<K,V> next() {
4573	<	nextEntry();
4574	<	return this;
4571	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4572	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4573	>	private static final long serialVersionUID = 2249069246763182397L;
4574	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4575	>
4576	>	public boolean contains(Object o) {
4577	>	Object k, v, r; Map.Entry<?,?> e;
4578	>	return ((o instanceof Map.Entry) &&
4579	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4580	>	(r = map.get(k)) != null &&
4581	>	(v = e.getValue()) != null &&
4582	>	(v == r || v.equals(r)));
4583		}
4584
4585	<	public K getKey() {
4586	<	if (lastReturned == null)
4587	<	throw new IllegalStateException("Entry was removed");
4588	<	return lastReturned.key;
4585	>	public boolean remove(Object o) {
4586	>	Object k, v; Map.Entry<?,?> e;
4587	>	return ((o instanceof Map.Entry) &&
4588	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4589	>	(v = e.getValue()) != null &&
4590	>	map.remove(k, v));
4591		}
4592
4593	<	public V getValue() {
4594	<	if (lastReturned == null)
4595	<	throw new IllegalStateException("Entry was removed");
4596	<	return ConcurrentHashMap.this.get(lastReturned.key);
4593	>	/**
4594	>	* @return an iterator over the entries of the backing map
4595	>	*/
4596	>	public Iterator<Map.Entry<K,V>> iterator() {
4597	>	ConcurrentHashMap<K,V> m = map;
4598	>	Node<K,V>[] t;
4599	>	int f = (t = m.table) == null ? 0 : t.length;
4600	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4601		}
4602
4603	<	public V setValue(V value) {
4604	<	if (lastReturned == null)
1194	<	throw new IllegalStateException("Entry was removed");
1195	<	return ConcurrentHashMap.this.put(lastReturned.key, value);
4603	>	public boolean add(Entry<K,V> e) {
4604	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4605		}
4606
4607	<	public boolean equals(Object o) {
4608	<	// If not acting as entry, just use default.
4609	<	if (lastReturned == null)
4610	<	return super.equals(o);
4611	<	if (!(o instanceof Map.Entry))
4612	<	return false;
4613	<	Map.Entry e = (Map.Entry)o;
1205	<	return eq(getKey(), e.getKey()) && eq(getValue(), e.getValue());
4607	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4608	>	boolean added = false;
4609	>	for (Entry<K,V> e : c) {
4610	>	if (add(e))
4611	>	added = true;
4612	>	}
4613	>	return added;
4614		}
4615
4616	<	public int hashCode() {
4617	<	// If not acting as entry, just use default.
4618	<	if (lastReturned == null)
4619	<	return super.hashCode();
4620	<
4621	<	Object k = getKey();
4622	<	Object v = getValue();
4623	<	return ((k == null) ? 0 : k.hashCode()) ^
4624	<	((v == null) ? 0 : v.hashCode());
4616	>	public final int hashCode() {
4617	>	int h = 0;
4618	>	Node<K,V>[] t;
4619	>	if ((t = map.table) != null) {
4620	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4621	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4622	>	h += p.hashCode();
4623	>	}
4624	>	}
4625	>	return h;
4626		}
4627
4628	<	public String toString() {
4629	<	// If not acting as entry, just use default.
4630	<	if (lastReturned == null)
4631	<	return super.toString();
4632	<	else
4633	<	return getKey() + "=" + getValue();
4628	>	public final boolean equals(Object o) {
4629	>	Set<?> c;
4630	>	return ((o instanceof Set) &&
4631	>	((c = (Set<?>)o) == this ||
4632	>	(containsAll(c) && c.containsAll(this))));
4633	>	}
4634	>
4635	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4636	>	Node<K,V>[] t;
4637	>	ConcurrentHashMap<K,V> m = map;
4638	>	long n = m.sumCount();
4639	>	int f = (t = m.table) == null ? 0 : t.length;
4640	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4641	>	}
4642	>
4643	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4644	>	if (action == null) throw new NullPointerException();
4645	>	Node<K,V>[] t;
4646	>	if ((t = map.table) != null) {
4647	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4648	>	for (Node<K,V> p; (p = it.advance()) != null; )
4649	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4650	>	}
4651		}
4652
4653	<	boolean eq(Object o1, Object o2) {
4654	<	return (o1 == null ? o2 == null : o1.equals(o2));
4653	>	}
4654	>
4655	>	// -------------------------------------------------------
4656	>
4657	>	/**
4658	>	* Base class for bulk tasks. Repeats some fields and code from
4659	>	* class Traverser, because we need to subclass CountedCompleter.
4660	>	*/
4661	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4662	>	Node<K,V>[] tab;        // same as Traverser
4663	>	Node<K,V> next;
4664	>	int index;
4665	>	int baseIndex;
4666	>	int baseLimit;
4667	>	final int baseSize;
4668	>	int batch;              // split control
4669	>
4670	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4671	>	super(par);
4672	>	this.batch = b;
4673	>	this.index = this.baseIndex = i;
4674	>	if ((this.tab = t) == null)
4675	>	this.baseSize = this.baseLimit = 0;
4676	>	else if (par == null)
4677	>	this.baseSize = this.baseLimit = t.length;
4678	>	else {
4679	>	this.baseLimit = f;
4680	>	this.baseSize = par.baseSize;
4681	>	}
4682		}
4683
4684	+	/**
4685	+	* Same as Traverser version
4686	+	*/
4687	+	final Node<K,V> advance() {
4688	+	Node<K,V> e;
4689	+	if ((e = next) != null)
4690	+	e = e.next;
4691	+	for (;;) {
4692	+	Node<K,V>[] t; int i, n; K ek;  // must use locals in checks
4693	+	if (e != null)
4694	+	return next = e;
4695	+	if (baseIndex >= baseLimit || (t = tab) == null ||
4696	+	(n = t.length) <= (i = index) || i < 0)
4697	+	return next = null;
4698	+	if ((e = tabAt(t, index)) != null && e.hash < 0) {
4699	+	if (e instanceof ForwardingNode) {
4700	+	tab = ((ForwardingNode<K,V>)e).nextTable;
4701	+	e = null;
4702	+	continue;
4703	+	}
4704	+	else if (e instanceof TreeBin)
4705	+	e = ((TreeBin<K,V>)e).first;
4706	+	else
4707	+	e = null;
4708	+	}
4709	+	if ((index += baseSize) >= n)
4710	+	index = ++baseIndex;    // visit upper slots if present
4711	+	}
4712	+	}
4713		}
4714
4715	<	final class KeySet extends AbstractSet<K> {
4716	<	public Iterator<K> iterator() {
4717	<	return new KeyIterator();
4715	>	/*
4716	>	* Task classes. Coded in a regular but ugly format/style to
4717	>	* simplify checks that each variant differs in the right way from
4718	>	* others. The null screenings exist because compilers cannot tell
4719	>	* that we've already null-checked task arguments, so we force
4720	>	* simplest hoisted bypass to help avoid convoluted traps.
4721	>	*/
4722	>	@SuppressWarnings("serial")
4723	>	static final class ForEachKeyTask<K,V>
4724	>	extends BulkTask<K,V,Void> {
4725	>	final Consumer<? super K> action;
4726	>	ForEachKeyTask
4727	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4728	>	Consumer<? super K> action) {
4729	>	super(p, b, i, f, t);
4730	>	this.action = action;
4731	>	}
4732	>	public final void compute() {
4733	>	final Consumer<? super K> action;
4734	>	if ((action = this.action) != null) {
4735	>	for (int i = baseIndex, f, h; batch > 0 &&
4736	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4737	>	addToPendingCount(1);
4738	>	new ForEachKeyTask<K,V>
4739	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4740	>	action).fork();
4741	>	}
4742	>	for (Node<K,V> p; (p = advance()) != null;)
4743	>	action.accept(p.key);
4744	>	propagateCompletion();
4745	>	}
4746		}
4747	<	public int size() {
4748	<	return ConcurrentHashMap.this.size();
4747	>	}
4748	>
4749	>	@SuppressWarnings("serial")
4750	>	static final class ForEachValueTask<K,V>
4751	>	extends BulkTask<K,V,Void> {
4752	>	final Consumer<? super V> action;
4753	>	ForEachValueTask
4754	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4755	>	Consumer<? super V> action) {
4756	>	super(p, b, i, f, t);
4757	>	this.action = action;
4758	>	}
4759	>	public final void compute() {
4760	>	final Consumer<? super V> action;
4761	>	if ((action = this.action) != null) {
4762	>	for (int i = baseIndex, f, h; batch > 0 &&
4763	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4764	>	addToPendingCount(1);
4765	>	new ForEachValueTask<K,V>
4766	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4767	>	action).fork();
4768	>	}
4769	>	for (Node<K,V> p; (p = advance()) != null;)
4770	>	action.accept(p.val);
4771	>	propagateCompletion();
4772	>	}
4773		}
4774	<	public boolean contains(Object o) {
4775	<	return ConcurrentHashMap.this.containsKey(o);
4774	>	}
4775	>
4776	>	@SuppressWarnings("serial")
4777	>	static final class ForEachEntryTask<K,V>
4778	>	extends BulkTask<K,V,Void> {
4779	>	final Consumer<? super Entry<K,V>> action;
4780	>	ForEachEntryTask
4781	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4782	>	Consumer<? super Entry<K,V>> action) {
4783	>	super(p, b, i, f, t);
4784	>	this.action = action;
4785	>	}
4786	>	public final void compute() {
4787	>	final Consumer<? super Entry<K,V>> action;
4788	>	if ((action = this.action) != null) {
4789	>	for (int i = baseIndex, f, h; batch > 0 &&
4790	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4791	>	addToPendingCount(1);
4792	>	new ForEachEntryTask<K,V>
4793	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4794	>	action).fork();
4795	>	}
4796	>	for (Node<K,V> p; (p = advance()) != null; )
4797	>	action.accept(p);
4798	>	propagateCompletion();
4799	>	}
4800		}
4801	<	public boolean remove(Object o) {
4802	<	return ConcurrentHashMap.this.remove(o) != null;
4801	>	}
4802	>
4803	>	@SuppressWarnings("serial")
4804	>	static final class ForEachMappingTask<K,V>
4805	>	extends BulkTask<K,V,Void> {
4806	>	final BiConsumer<? super K, ? super V> action;
4807	>	ForEachMappingTask
4808	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4809	>	BiConsumer<? super K,? super V> action) {
4810	>	super(p, b, i, f, t);
4811	>	this.action = action;
4812	>	}
4813	>	public final void compute() {
4814	>	final BiConsumer<? super K, ? super V> action;
4815	>	if ((action = this.action) != null) {
4816	>	for (int i = baseIndex, f, h; batch > 0 &&
4817	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4818	>	addToPendingCount(1);
4819	>	new ForEachMappingTask<K,V>
4820	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4821	>	action).fork();
4822	>	}
4823	>	for (Node<K,V> p; (p = advance()) != null; )
4824	>	action.accept(p.key, p.val);
4825	>	propagateCompletion();
4826	>	}
4827		}
4828	<	public void clear() {
4829	<	ConcurrentHashMap.this.clear();
4828	>	}
4829	>
4830	>	@SuppressWarnings("serial")
4831	>	static final class ForEachTransformedKeyTask<K,V,U>
4832	>	extends BulkTask<K,V,Void> {
4833	>	final Function<? super K, ? extends U> transformer;
4834	>	final Consumer<? super U> action;
4835	>	ForEachTransformedKeyTask
4836	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4837	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4838	>	super(p, b, i, f, t);
4839	>	this.transformer = transformer; this.action = action;
4840	>	}
4841	>	public final void compute() {
4842	>	final Function<? super K, ? extends U> transformer;
4843	>	final Consumer<? super U> action;
4844	>	if ((transformer = this.transformer) != null &&
4845	>	(action = this.action) != null) {
4846	>	for (int i = baseIndex, f, h; batch > 0 &&
4847	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4848	>	addToPendingCount(1);
4849	>	new ForEachTransformedKeyTask<K,V,U>
4850	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4851	>	transformer, action).fork();
4852	>	}
4853	>	for (Node<K,V> p; (p = advance()) != null; ) {
4854	>	U u;
4855	>	if ((u = transformer.apply(p.key)) != null)
4856	>	action.accept(u);
4857	>	}
4858	>	propagateCompletion();
4859	>	}
4860		}
4861	<	public Object[] toArray() {
4862	<	Collection<K> c = new ArrayList<K>();
4863	<	for (Iterator<K> i = iterator(); i.hasNext(); )
4864	<	c.add(i.next());
4865	<	return c.toArray();
4861	>	}
4862	>
4863	>	@SuppressWarnings("serial")
4864	>	static final class ForEachTransformedValueTask<K,V,U>
4865	>	extends BulkTask<K,V,Void> {
4866	>	final Function<? super V, ? extends U> transformer;
4867	>	final Consumer<? super U> action;
4868	>	ForEachTransformedValueTask
4869	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4870	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
4871	>	super(p, b, i, f, t);
4872	>	this.transformer = transformer; this.action = action;
4873	>	}
4874	>	public final void compute() {
4875	>	final Function<? super V, ? extends U> transformer;
4876	>	final Consumer<? super U> action;
4877	>	if ((transformer = this.transformer) != null &&
4878	>	(action = this.action) != null) {
4879	>	for (int i = baseIndex, f, h; batch > 0 &&
4880	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4881	>	addToPendingCount(1);
4882	>	new ForEachTransformedValueTask<K,V,U>
4883	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4884	>	transformer, action).fork();
4885	>	}
4886	>	for (Node<K,V> p; (p = advance()) != null; ) {
4887	>	U u;
4888	>	if ((u = transformer.apply(p.val)) != null)
4889	>	action.accept(u);
4890	>	}
4891	>	propagateCompletion();
4892	>	}
4893		}
4894	<	public <T> T[] toArray(T[] a) {
4895	<	Collection<K> c = new ArrayList<K>();
4896	<	for (Iterator<K> i = iterator(); i.hasNext(); )
4897	<	c.add(i.next());
4898	<	return c.toArray(a);
4894	>	}
4895	>
4896	>	@SuppressWarnings("serial")
4897	>	static final class ForEachTransformedEntryTask<K,V,U>
4898	>	extends BulkTask<K,V,Void> {
4899	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
4900	>	final Consumer<? super U> action;
4901	>	ForEachTransformedEntryTask
4902	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4903	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
4904	>	super(p, b, i, f, t);
4905	>	this.transformer = transformer; this.action = action;
4906	>	}
4907	>	public final void compute() {
4908	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
4909	>	final Consumer<? super U> action;
4910	>	if ((transformer = this.transformer) != null &&
4911	>	(action = this.action) != null) {
4912	>	for (int i = baseIndex, f, h; batch > 0 &&
4913	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4914	>	addToPendingCount(1);
4915	>	new ForEachTransformedEntryTask<K,V,U>
4916	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4917	>	transformer, action).fork();
4918	>	}
4919	>	for (Node<K,V> p; (p = advance()) != null; ) {
4920	>	U u;
4921	>	if ((u = transformer.apply(p)) != null)
4922	>	action.accept(u);
4923	>	}
4924	>	propagateCompletion();
4925	>	}
4926		}
4927		}
4928
4929	<	final class Values extends AbstractCollection<V> {
4930	<	public Iterator<V> iterator() {
4931	<	return new ValueIterator();
4929	>	@SuppressWarnings("serial")
4930	>	static final class ForEachTransformedMappingTask<K,V,U>
4931	>	extends BulkTask<K,V,Void> {
4932	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
4933	>	final Consumer<? super U> action;
4934	>	ForEachTransformedMappingTask
4935	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4936	>	BiFunction<? super K, ? super V, ? extends U> transformer,
4937	>	Consumer<? super U> action) {
4938	>	super(p, b, i, f, t);
4939	>	this.transformer = transformer; this.action = action;
4940	>	}
4941	>	public final void compute() {
4942	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
4943	>	final Consumer<? super U> action;
4944	>	if ((transformer = this.transformer) != null &&
4945	>	(action = this.action) != null) {
4946	>	for (int i = baseIndex, f, h; batch > 0 &&
4947	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4948	>	addToPendingCount(1);
4949	>	new ForEachTransformedMappingTask<K,V,U>
4950	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4951	>	transformer, action).fork();
4952	>	}
4953	>	for (Node<K,V> p; (p = advance()) != null; ) {
4954	>	U u;
4955	>	if ((u = transformer.apply(p.key, p.val)) != null)
4956	>	action.accept(u);
4957	>	}
4958	>	propagateCompletion();
4959	>	}
4960		}
4961	<	public int size() {
4962	<	return ConcurrentHashMap.this.size();
4961	>	}
4962	>
4963	>	@SuppressWarnings("serial")
4964	>	static final class SearchKeysTask<K,V,U>
4965	>	extends BulkTask<K,V,U> {
4966	>	final Function<? super K, ? extends U> searchFunction;
4967	>	final AtomicReference<U> result;
4968	>	SearchKeysTask
4969	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4970	>	Function<? super K, ? extends U> searchFunction,
4971	>	AtomicReference<U> result) {
4972	>	super(p, b, i, f, t);
4973	>	this.searchFunction = searchFunction; this.result = result;
4974	>	}
4975	>	public final U getRawResult() { return result.get(); }
4976	>	public final void compute() {
4977	>	final Function<? super K, ? extends U> searchFunction;
4978	>	final AtomicReference<U> result;
4979	>	if ((searchFunction = this.searchFunction) != null &&
4980	>	(result = this.result) != null) {
4981	>	for (int i = baseIndex, f, h; batch > 0 &&
4982	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4983	>	if (result.get() != null)
4984	>	return;
4985	>	addToPendingCount(1);
4986	>	new SearchKeysTask<K,V,U>
4987	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4988	>	searchFunction, result).fork();
4989	>	}
4990	>	while (result.get() == null) {
4991	>	U u;
4992	>	Node<K,V> p;
4993	>	if ((p = advance()) == null) {
4994	>	propagateCompletion();
4995	>	break;
4996	>	}
4997	>	if ((u = searchFunction.apply(p.key)) != null) {
4998	>	if (result.compareAndSet(null, u))
4999	>	quietlyCompleteRoot();
5000	>	break;
5001	>	}
5002	>	}
5003	>	}
5004		}
5005	<	public boolean contains(Object o) {
5006	<	return ConcurrentHashMap.this.containsValue(o);
5005	>	}
5006	>
5007	>	@SuppressWarnings("serial")
5008	>	static final class SearchValuesTask<K,V,U>
5009	>	extends BulkTask<K,V,U> {
5010	>	final Function<? super V, ? extends U> searchFunction;
5011	>	final AtomicReference<U> result;
5012	>	SearchValuesTask
5013	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5014	>	Function<? super V, ? extends U> searchFunction,
5015	>	AtomicReference<U> result) {
5016	>	super(p, b, i, f, t);
5017	>	this.searchFunction = searchFunction; this.result = result;
5018	>	}
5019	>	public final U getRawResult() { return result.get(); }
5020	>	public final void compute() {
5021	>	final Function<? super V, ? extends U> searchFunction;
5022	>	final AtomicReference<U> result;
5023	>	if ((searchFunction = this.searchFunction) != null &&
5024	>	(result = this.result) != null) {
5025	>	for (int i = baseIndex, f, h; batch > 0 &&
5026	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5027	>	if (result.get() != null)
5028	>	return;
5029	>	addToPendingCount(1);
5030	>	new SearchValuesTask<K,V,U>
5031	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5032	>	searchFunction, result).fork();
5033	>	}
5034	>	while (result.get() == null) {
5035	>	U u;
5036	>	Node<K,V> p;
5037	>	if ((p = advance()) == null) {
5038	>	propagateCompletion();
5039	>	break;
5040	>	}
5041	>	if ((u = searchFunction.apply(p.val)) != null) {
5042	>	if (result.compareAndSet(null, u))
5043	>	quietlyCompleteRoot();
5044	>	break;
5045	>	}
5046	>	}
5047	>	}
5048		}
5049	<	public void clear() {
5050	<	ConcurrentHashMap.this.clear();
5049	>	}
5050	>
5051	>	@SuppressWarnings("serial")
5052	>	static final class SearchEntriesTask<K,V,U>
5053	>	extends BulkTask<K,V,U> {
5054	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5055	>	final AtomicReference<U> result;
5056	>	SearchEntriesTask
5057	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5058	>	Function<Entry<K,V>, ? extends U> searchFunction,
5059	>	AtomicReference<U> result) {
5060	>	super(p, b, i, f, t);
5061	>	this.searchFunction = searchFunction; this.result = result;
5062	>	}
5063	>	public final U getRawResult() { return result.get(); }
5064	>	public final void compute() {
5065	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5066	>	final AtomicReference<U> result;
5067	>	if ((searchFunction = this.searchFunction) != null &&
5068	>	(result = this.result) != null) {
5069	>	for (int i = baseIndex, f, h; batch > 0 &&
5070	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5071	>	if (result.get() != null)
5072	>	return;
5073	>	addToPendingCount(1);
5074	>	new SearchEntriesTask<K,V,U>
5075	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5076	>	searchFunction, result).fork();
5077	>	}
5078	>	while (result.get() == null) {
5079	>	U u;
5080	>	Node<K,V> p;
5081	>	if ((p = advance()) == null) {
5082	>	propagateCompletion();
5083	>	break;
5084	>	}
5085	>	if ((u = searchFunction.apply(p)) != null) {
5086	>	if (result.compareAndSet(null, u))
5087	>	quietlyCompleteRoot();
5088	>	return;
5089	>	}
5090	>	}
5091	>	}
5092		}
5093	<	public Object[] toArray() {
5094	<	Collection<V> c = new ArrayList<V>();
5095	<	for (Iterator<V> i = iterator(); i.hasNext(); )
5096	<	c.add(i.next());
5097	<	return c.toArray();
5093	>	}
5094	>
5095	>	@SuppressWarnings("serial")
5096	>	static final class SearchMappingsTask<K,V,U>
5097	>	extends BulkTask<K,V,U> {
5098	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5099	>	final AtomicReference<U> result;
5100	>	SearchMappingsTask
5101	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5102	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5103	>	AtomicReference<U> result) {
5104	>	super(p, b, i, f, t);
5105	>	this.searchFunction = searchFunction; this.result = result;
5106	>	}
5107	>	public final U getRawResult() { return result.get(); }
5108	>	public final void compute() {
5109	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5110	>	final AtomicReference<U> result;
5111	>	if ((searchFunction = this.searchFunction) != null &&
5112	>	(result = this.result) != null) {
5113	>	for (int i = baseIndex, f, h; batch > 0 &&
5114	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5115	>	if (result.get() != null)
5116	>	return;
5117	>	addToPendingCount(1);
5118	>	new SearchMappingsTask<K,V,U>
5119	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5120	>	searchFunction, result).fork();
5121	>	}
5122	>	while (result.get() == null) {
5123	>	U u;
5124	>	Node<K,V> p;
5125	>	if ((p = advance()) == null) {
5126	>	propagateCompletion();
5127	>	break;
5128	>	}
5129	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5130	>	if (result.compareAndSet(null, u))
5131	>	quietlyCompleteRoot();
5132	>	break;
5133	>	}
5134	>	}
5135	>	}
5136		}
5137	<	public <T> T[] toArray(T[] a) {
5138	<	Collection<V> c = new ArrayList<V>();
5139	<	for (Iterator<V> i = iterator(); i.hasNext(); )
5140	<	c.add(i.next());
5141	<	return c.toArray(a);
5137	>	}
5138	>
5139	>	@SuppressWarnings("serial")
5140	>	static final class ReduceKeysTask<K,V>
5141	>	extends BulkTask<K,V,K> {
5142	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5143	>	K result;
5144	>	ReduceKeysTask<K,V> rights, nextRight;
5145	>	ReduceKeysTask
5146	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5147	>	ReduceKeysTask<K,V> nextRight,
5148	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5149	>	super(p, b, i, f, t); this.nextRight = nextRight;
5150	>	this.reducer = reducer;
5151	>	}
5152	>	public final K getRawResult() { return result; }
5153	>	public final void compute() {
5154	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5155	>	if ((reducer = this.reducer) != null) {
5156	>	for (int i = baseIndex, f, h; batch > 0 &&
5157	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5158	>	addToPendingCount(1);
5159	>	(rights = new ReduceKeysTask<K,V>
5160	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5161	>	rights, reducer)).fork();
5162	>	}
5163	>	K r = null;
5164	>	for (Node<K,V> p; (p = advance()) != null; ) {
5165	>	K u = p.key;
5166	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5167	>	}
5168	>	result = r;
5169	>	CountedCompleter<?> c;
5170	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5171	>	@SuppressWarnings("unchecked") ReduceKeysTask<K,V>
5172	>	t = (ReduceKeysTask<K,V>)c,
5173	>	s = t.rights;
5174	>	while (s != null) {
5175	>	K tr, sr;
5176	>	if ((sr = s.result) != null)
5177	>	t.result = (((tr = t.result) == null) ? sr :
5178	>	reducer.apply(tr, sr));
5179	>	s = t.rights = s.nextRight;
5180	>	}
5181	>	}
5182	>	}
5183		}
5184		}
5185
5186	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
5187	<	public Iterator<Map.Entry<K,V>> iterator() {
5188	<	return new EntryIterator();
5186	>	@SuppressWarnings("serial")
5187	>	static final class ReduceValuesTask<K,V>
5188	>	extends BulkTask<K,V,V> {
5189	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5190	>	V result;
5191	>	ReduceValuesTask<K,V> rights, nextRight;
5192	>	ReduceValuesTask
5193	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5194	>	ReduceValuesTask<K,V> nextRight,
5195	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5196	>	super(p, b, i, f, t); this.nextRight = nextRight;
5197	>	this.reducer = reducer;
5198	>	}
5199	>	public final V getRawResult() { return result; }
5200	>	public final void compute() {
5201	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5202	>	if ((reducer = this.reducer) != null) {
5203	>	for (int i = baseIndex, f, h; batch > 0 &&
5204	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5205	>	addToPendingCount(1);
5206	>	(rights = new ReduceValuesTask<K,V>
5207	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5208	>	rights, reducer)).fork();
5209	>	}
5210	>	V r = null;
5211	>	for (Node<K,V> p; (p = advance()) != null; ) {
5212	>	V v = p.val;
5213	>	r = (r == null) ? v : reducer.apply(r, v);
5214	>	}
5215	>	result = r;
5216	>	CountedCompleter<?> c;
5217	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5218	>	@SuppressWarnings("unchecked") ReduceValuesTask<K,V>
5219	>	t = (ReduceValuesTask<K,V>)c,
5220	>	s = t.rights;
5221	>	while (s != null) {
5222	>	V tr, sr;
5223	>	if ((sr = s.result) != null)
5224	>	t.result = (((tr = t.result) == null) ? sr :
5225	>	reducer.apply(tr, sr));
5226	>	s = t.rights = s.nextRight;
5227	>	}
5228	>	}
5229	>	}
5230		}
5231	<	public boolean contains(Object o) {
5232	<	if (!(o instanceof Map.Entry))
5233	<	return false;
5234	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5235	<	V v = ConcurrentHashMap.this.get(e.getKey());
5236	<	return v != null && v.equals(e.getValue());
5231	>	}
5232	>
5233	>	@SuppressWarnings("serial")
5234	>	static final class ReduceEntriesTask<K,V>
5235	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5236	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5237	>	Map.Entry<K,V> result;
5238	>	ReduceEntriesTask<K,V> rights, nextRight;
5239	>	ReduceEntriesTask
5240	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5241	>	ReduceEntriesTask<K,V> nextRight,
5242	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5243	>	super(p, b, i, f, t); this.nextRight = nextRight;
5244	>	this.reducer = reducer;
5245	>	}
5246	>	public final Map.Entry<K,V> getRawResult() { return result; }
5247	>	public final void compute() {
5248	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5249	>	if ((reducer = this.reducer) != null) {
5250	>	for (int i = baseIndex, f, h; batch > 0 &&
5251	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5252	>	addToPendingCount(1);
5253	>	(rights = new ReduceEntriesTask<K,V>
5254	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5255	>	rights, reducer)).fork();
5256	>	}
5257	>	Map.Entry<K,V> r = null;
5258	>	for (Node<K,V> p; (p = advance()) != null; )
5259	>	r = (r == null) ? p : reducer.apply(r, p);
5260	>	result = r;
5261	>	CountedCompleter<?> c;
5262	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5263	>	@SuppressWarnings("unchecked") ReduceEntriesTask<K,V>
5264	>	t = (ReduceEntriesTask<K,V>)c,
5265	>	s = t.rights;
5266	>	while (s != null) {
5267	>	Map.Entry<K,V> tr, sr;
5268	>	if ((sr = s.result) != null)
5269	>	t.result = (((tr = t.result) == null) ? sr :
5270	>	reducer.apply(tr, sr));
5271	>	s = t.rights = s.nextRight;
5272	>	}
5273	>	}
5274	>	}
5275		}
5276	<	public boolean remove(Object o) {
5277	<	if (!(o instanceof Map.Entry))
5278	<	return false;
5279	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5280	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
5276	>	}
5277	>
5278	>	@SuppressWarnings("serial")
5279	>	static final class MapReduceKeysTask<K,V,U>
5280	>	extends BulkTask<K,V,U> {
5281	>	final Function<? super K, ? extends U> transformer;
5282	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5283	>	U result;
5284	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5285	>	MapReduceKeysTask
5286	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5287	>	MapReduceKeysTask<K,V,U> nextRight,
5288	>	Function<? super K, ? extends U> transformer,
5289	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5290	>	super(p, b, i, f, t); this.nextRight = nextRight;
5291	>	this.transformer = transformer;
5292	>	this.reducer = reducer;
5293	>	}
5294	>	public final U getRawResult() { return result; }
5295	>	public final void compute() {
5296	>	final Function<? super K, ? extends U> transformer;
5297	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5298	>	if ((transformer = this.transformer) != null &&
5299	>	(reducer = this.reducer) != null) {
5300	>	for (int i = baseIndex, f, h; batch > 0 &&
5301	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5302	>	addToPendingCount(1);
5303	>	(rights = new MapReduceKeysTask<K,V,U>
5304	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5305	>	rights, transformer, reducer)).fork();
5306	>	}
5307	>	U r = null;
5308	>	for (Node<K,V> p; (p = advance()) != null; ) {
5309	>	U u;
5310	>	if ((u = transformer.apply(p.key)) != null)
5311	>	r = (r == null) ? u : reducer.apply(r, u);
5312	>	}
5313	>	result = r;
5314	>	CountedCompleter<?> c;
5315	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5316	>	@SuppressWarnings("unchecked") MapReduceKeysTask<K,V,U>
5317	>	t = (MapReduceKeysTask<K,V,U>)c,
5318	>	s = t.rights;
5319	>	while (s != null) {
5320	>	U tr, sr;
5321	>	if ((sr = s.result) != null)
5322	>	t.result = (((tr = t.result) == null) ? sr :
5323	>	reducer.apply(tr, sr));
5324	>	s = t.rights = s.nextRight;
5325	>	}
5326	>	}
5327	>	}
5328	>	}
5329	>	}
5330	>
5331	>	@SuppressWarnings("serial")
5332	>	static final class MapReduceValuesTask<K,V,U>
5333	>	extends BulkTask<K,V,U> {
5334	>	final Function<? super V, ? extends U> transformer;
5335	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5336	>	U result;
5337	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5338	>	MapReduceValuesTask
5339	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5340	>	MapReduceValuesTask<K,V,U> nextRight,
5341	>	Function<? super V, ? extends U> transformer,
5342	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5343	>	super(p, b, i, f, t); this.nextRight = nextRight;
5344	>	this.transformer = transformer;
5345	>	this.reducer = reducer;
5346	>	}
5347	>	public final U getRawResult() { return result; }
5348	>	public final void compute() {
5349	>	final Function<? super V, ? extends U> transformer;
5350	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5351	>	if ((transformer = this.transformer) != null &&
5352	>	(reducer = this.reducer) != null) {
5353	>	for (int i = baseIndex, f, h; batch > 0 &&
5354	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5355	>	addToPendingCount(1);
5356	>	(rights = new MapReduceValuesTask<K,V,U>
5357	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5358	>	rights, transformer, reducer)).fork();
5359	>	}
5360	>	U r = null;
5361	>	for (Node<K,V> p; (p = advance()) != null; ) {
5362	>	U u;
5363	>	if ((u = transformer.apply(p.val)) != null)
5364	>	r = (r == null) ? u : reducer.apply(r, u);
5365	>	}
5366	>	result = r;
5367	>	CountedCompleter<?> c;
5368	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5369	>	@SuppressWarnings("unchecked") MapReduceValuesTask<K,V,U>
5370	>	t = (MapReduceValuesTask<K,V,U>)c,
5371	>	s = t.rights;
5372	>	while (s != null) {
5373	>	U tr, sr;
5374	>	if ((sr = s.result) != null)
5375	>	t.result = (((tr = t.result) == null) ? sr :
5376	>	reducer.apply(tr, sr));
5377	>	s = t.rights = s.nextRight;
5378	>	}
5379	>	}
5380	>	}
5381	>	}
5382	>	}
5383	>
5384	>	@SuppressWarnings("serial")
5385	>	static final class MapReduceEntriesTask<K,V,U>
5386	>	extends BulkTask<K,V,U> {
5387	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5388	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5389	>	U result;
5390	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5391	>	MapReduceEntriesTask
5392	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5393	>	MapReduceEntriesTask<K,V,U> nextRight,
5394	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5395	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5396	>	super(p, b, i, f, t); this.nextRight = nextRight;
5397	>	this.transformer = transformer;
5398	>	this.reducer = reducer;
5399	>	}
5400	>	public final U getRawResult() { return result; }
5401	>	public final void compute() {
5402	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5403	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5404	>	if ((transformer = this.transformer) != null &&
5405	>	(reducer = this.reducer) != null) {
5406	>	for (int i = baseIndex, f, h; batch > 0 &&
5407	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5408	>	addToPendingCount(1);
5409	>	(rights = new MapReduceEntriesTask<K,V,U>
5410	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5411	>	rights, transformer, reducer)).fork();
5412	>	}
5413	>	U r = null;
5414	>	for (Node<K,V> p; (p = advance()) != null; ) {
5415	>	U u;
5416	>	if ((u = transformer.apply(p)) != null)
5417	>	r = (r == null) ? u : reducer.apply(r, u);
5418	>	}
5419	>	result = r;
5420	>	CountedCompleter<?> c;
5421	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5422	>	@SuppressWarnings("unchecked") MapReduceEntriesTask<K,V,U>
5423	>	t = (MapReduceEntriesTask<K,V,U>)c,
5424	>	s = t.rights;
5425	>	while (s != null) {
5426	>	U tr, sr;
5427	>	if ((sr = s.result) != null)
5428	>	t.result = (((tr = t.result) == null) ? sr :
5429	>	reducer.apply(tr, sr));
5430	>	s = t.rights = s.nextRight;
5431	>	}
5432	>	}
5433	>	}
5434	>	}
5435	>	}
5436	>
5437	>	@SuppressWarnings("serial")
5438	>	static final class MapReduceMappingsTask<K,V,U>
5439	>	extends BulkTask<K,V,U> {
5440	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5441	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5442	>	U result;
5443	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5444	>	MapReduceMappingsTask
5445	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5446	>	MapReduceMappingsTask<K,V,U> nextRight,
5447	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5448	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5449	>	super(p, b, i, f, t); this.nextRight = nextRight;
5450	>	this.transformer = transformer;
5451	>	this.reducer = reducer;
5452	>	}
5453	>	public final U getRawResult() { return result; }
5454	>	public final void compute() {
5455	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5456	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5457	>	if ((transformer = this.transformer) != null &&
5458	>	(reducer = this.reducer) != null) {
5459	>	for (int i = baseIndex, f, h; batch > 0 &&
5460	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5461	>	addToPendingCount(1);
5462	>	(rights = new MapReduceMappingsTask<K,V,U>
5463	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5464	>	rights, transformer, reducer)).fork();
5465	>	}
5466	>	U r = null;
5467	>	for (Node<K,V> p; (p = advance()) != null; ) {
5468	>	U u;
5469	>	if ((u = transformer.apply(p.key, p.val)) != null)
5470	>	r = (r == null) ? u : reducer.apply(r, u);
5471	>	}
5472	>	result = r;
5473	>	CountedCompleter<?> c;
5474	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5475	>	@SuppressWarnings("unchecked") MapReduceMappingsTask<K,V,U>
5476	>	t = (MapReduceMappingsTask<K,V,U>)c,
5477	>	s = t.rights;
5478	>	while (s != null) {
5479	>	U tr, sr;
5480	>	if ((sr = s.result) != null)
5481	>	t.result = (((tr = t.result) == null) ? sr :
5482	>	reducer.apply(tr, sr));
5483	>	s = t.rights = s.nextRight;
5484	>	}
5485	>	}
5486	>	}
5487	>	}
5488	>	}
5489	>
5490	>	@SuppressWarnings("serial")
5491	>	static final class MapReduceKeysToDoubleTask<K,V>
5492	>	extends BulkTask<K,V,Double> {
5493	>	final ToDoubleFunction<? super K> transformer;
5494	>	final DoubleBinaryOperator reducer;
5495	>	final double basis;
5496	>	double result;
5497	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5498	>	MapReduceKeysToDoubleTask
5499	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5500	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5501	>	ToDoubleFunction<? super K> transformer,
5502	>	double basis,
5503	>	DoubleBinaryOperator reducer) {
5504	>	super(p, b, i, f, t); this.nextRight = nextRight;
5505	>	this.transformer = transformer;
5506	>	this.basis = basis; this.reducer = reducer;
5507	>	}
5508	>	public final Double getRawResult() { return result; }
5509	>	public final void compute() {
5510	>	final ToDoubleFunction<? super K> transformer;
5511	>	final DoubleBinaryOperator reducer;
5512	>	if ((transformer = this.transformer) != null &&
5513	>	(reducer = this.reducer) != null) {
5514	>	double r = this.basis;
5515	>	for (int i = baseIndex, f, h; batch > 0 &&
5516	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5517	>	addToPendingCount(1);
5518	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5519	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5520	>	rights, transformer, r, reducer)).fork();
5521	>	}
5522	>	for (Node<K,V> p; (p = advance()) != null; )
5523	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5524	>	result = r;
5525	>	CountedCompleter<?> c;
5526	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5527	>	@SuppressWarnings("unchecked") MapReduceKeysToDoubleTask<K,V>
5528	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5529	>	s = t.rights;
5530	>	while (s != null) {
5531	>	t.result = reducer.applyAsDouble(t.result, s.result);
5532	>	s = t.rights = s.nextRight;
5533	>	}
5534	>	}
5535	>	}
5536		}
5537	<	public int size() {
5538	<	return ConcurrentHashMap.this.size();
5537	>	}
5538	>
5539	>	@SuppressWarnings("serial")
5540	>	static final class MapReduceValuesToDoubleTask<K,V>
5541	>	extends BulkTask<K,V,Double> {
5542	>	final ToDoubleFunction<? super V> transformer;
5543	>	final DoubleBinaryOperator reducer;
5544	>	final double basis;
5545	>	double result;
5546	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5547	>	MapReduceValuesToDoubleTask
5548	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5549	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5550	>	ToDoubleFunction<? super V> transformer,
5551	>	double basis,
5552	>	DoubleBinaryOperator reducer) {
5553	>	super(p, b, i, f, t); this.nextRight = nextRight;
5554	>	this.transformer = transformer;
5555	>	this.basis = basis; this.reducer = reducer;
5556	>	}
5557	>	public final Double getRawResult() { return result; }
5558	>	public final void compute() {
5559	>	final ToDoubleFunction<? super V> transformer;
5560	>	final DoubleBinaryOperator reducer;
5561	>	if ((transformer = this.transformer) != null &&
5562	>	(reducer = this.reducer) != null) {
5563	>	double r = this.basis;
5564	>	for (int i = baseIndex, f, h; batch > 0 &&
5565	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5566	>	addToPendingCount(1);
5567	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5568	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5569	>	rights, transformer, r, reducer)).fork();
5570	>	}
5571	>	for (Node<K,V> p; (p = advance()) != null; )
5572	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5573	>	result = r;
5574	>	CountedCompleter<?> c;
5575	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5576	>	@SuppressWarnings("unchecked") MapReduceValuesToDoubleTask<K,V>
5577	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5578	>	s = t.rights;
5579	>	while (s != null) {
5580	>	t.result = reducer.applyAsDouble(t.result, s.result);
5581	>	s = t.rights = s.nextRight;
5582	>	}
5583	>	}
5584	>	}
5585		}
5586	<	public void clear() {
5587	<	ConcurrentHashMap.this.clear();
5586	>	}
5587	>
5588	>	@SuppressWarnings("serial")
5589	>	static final class MapReduceEntriesToDoubleTask<K,V>
5590	>	extends BulkTask<K,V,Double> {
5591	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5592	>	final DoubleBinaryOperator reducer;
5593	>	final double basis;
5594	>	double result;
5595	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5596	>	MapReduceEntriesToDoubleTask
5597	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5598	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5599	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5600	>	double basis,
5601	>	DoubleBinaryOperator reducer) {
5602	>	super(p, b, i, f, t); this.nextRight = nextRight;
5603	>	this.transformer = transformer;
5604	>	this.basis = basis; this.reducer = reducer;
5605	>	}
5606	>	public final Double getRawResult() { return result; }
5607	>	public final void compute() {
5608	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5609	>	final DoubleBinaryOperator reducer;
5610	>	if ((transformer = this.transformer) != null &&
5611	>	(reducer = this.reducer) != null) {
5612	>	double r = this.basis;
5613	>	for (int i = baseIndex, f, h; batch > 0 &&
5614	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5615	>	addToPendingCount(1);
5616	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5617	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5618	>	rights, transformer, r, reducer)).fork();
5619	>	}
5620	>	for (Node<K,V> p; (p = advance()) != null; )
5621	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5622	>	result = r;
5623	>	CountedCompleter<?> c;
5624	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5625	>	@SuppressWarnings("unchecked") MapReduceEntriesToDoubleTask<K,V>
5626	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5627	>	s = t.rights;
5628	>	while (s != null) {
5629	>	t.result = reducer.applyAsDouble(t.result, s.result);
5630	>	s = t.rights = s.nextRight;
5631	>	}
5632	>	}
5633	>	}
5634		}
5635	<	public Object[] toArray() {
5636	<	// Since we don't ordinarily have distinct Entry objects, we
5637	<	// must pack elements using exportable SimpleEntry
5638	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
5639	<	for (Iterator<Map.Entry<K,V>> i = iterator(); i.hasNext(); )
5640	<	c.add(new AbstractMap.SimpleEntry<K,V>(i.next()));
5641	<	return c.toArray();
5635	>	}
5636	>
5637	>	@SuppressWarnings("serial")
5638	>	static final class MapReduceMappingsToDoubleTask<K,V>
5639	>	extends BulkTask<K,V,Double> {
5640	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5641	>	final DoubleBinaryOperator reducer;
5642	>	final double basis;
5643	>	double result;
5644	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5645	>	MapReduceMappingsToDoubleTask
5646	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5647	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5648	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5649	>	double basis,
5650	>	DoubleBinaryOperator reducer) {
5651	>	super(p, b, i, f, t); this.nextRight = nextRight;
5652	>	this.transformer = transformer;
5653	>	this.basis = basis; this.reducer = reducer;
5654	>	}
5655	>	public final Double getRawResult() { return result; }
5656	>	public final void compute() {
5657	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5658	>	final DoubleBinaryOperator reducer;
5659	>	if ((transformer = this.transformer) != null &&
5660	>	(reducer = this.reducer) != null) {
5661	>	double r = this.basis;
5662	>	for (int i = baseIndex, f, h; batch > 0 &&
5663	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5664	>	addToPendingCount(1);
5665	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5666	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5667	>	rights, transformer, r, reducer)).fork();
5668	>	}
5669	>	for (Node<K,V> p; (p = advance()) != null; )
5670	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5671	>	result = r;
5672	>	CountedCompleter<?> c;
5673	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5674	>	@SuppressWarnings("unchecked") MapReduceMappingsToDoubleTask<K,V>
5675	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5676	>	s = t.rights;
5677	>	while (s != null) {
5678	>	t.result = reducer.applyAsDouble(t.result, s.result);
5679	>	s = t.rights = s.nextRight;
5680	>	}
5681	>	}
5682	>	}
5683		}
5684	<	public <T> T[] toArray(T[] a) {
5685	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
5686	<	for (Iterator<Map.Entry<K,V>> i = iterator(); i.hasNext(); )
5687	<	c.add(new AbstractMap.SimpleEntry<K,V>(i.next()));
5688	<	return c.toArray(a);
5684	>	}
5685	>
5686	>	@SuppressWarnings("serial")
5687	>	static final class MapReduceKeysToLongTask<K,V>
5688	>	extends BulkTask<K,V,Long> {
5689	>	final ToLongFunction<? super K> transformer;
5690	>	final LongBinaryOperator reducer;
5691	>	final long basis;
5692	>	long result;
5693	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5694	>	MapReduceKeysToLongTask
5695	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5696	>	MapReduceKeysToLongTask<K,V> nextRight,
5697	>	ToLongFunction<? super K> transformer,
5698	>	long basis,
5699	>	LongBinaryOperator reducer) {
5700	>	super(p, b, i, f, t); this.nextRight = nextRight;
5701	>	this.transformer = transformer;
5702	>	this.basis = basis; this.reducer = reducer;
5703	>	}
5704	>	public final Long getRawResult() { return result; }
5705	>	public final void compute() {
5706	>	final ToLongFunction<? super K> transformer;
5707	>	final LongBinaryOperator reducer;
5708	>	if ((transformer = this.transformer) != null &&
5709	>	(reducer = this.reducer) != null) {
5710	>	long r = this.basis;
5711	>	for (int i = baseIndex, f, h; batch > 0 &&
5712	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5713	>	addToPendingCount(1);
5714	>	(rights = new MapReduceKeysToLongTask<K,V>
5715	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5716	>	rights, transformer, r, reducer)).fork();
5717	>	}
5718	>	for (Node<K,V> p; (p = advance()) != null; )
5719	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5720	>	result = r;
5721	>	CountedCompleter<?> c;
5722	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5723	>	@SuppressWarnings("unchecked") MapReduceKeysToLongTask<K,V>
5724	>	t = (MapReduceKeysToLongTask<K,V>)c,
5725	>	s = t.rights;
5726	>	while (s != null) {
5727	>	t.result = reducer.applyAsLong(t.result, s.result);
5728	>	s = t.rights = s.nextRight;
5729	>	}
5730	>	}
5731	>	}
5732		}
5733	+	}
5734
5735	+	@SuppressWarnings("serial")
5736	+	static final class MapReduceValuesToLongTask<K,V>
5737	+	extends BulkTask<K,V,Long> {
5738	+	final ToLongFunction<? super V> transformer;
5739	+	final LongBinaryOperator reducer;
5740	+	final long basis;
5741	+	long result;
5742	+	MapReduceValuesToLongTask<K,V> rights, nextRight;
5743	+	MapReduceValuesToLongTask
5744	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5745	+	MapReduceValuesToLongTask<K,V> nextRight,
5746	+	ToLongFunction<? super V> transformer,
5747	+	long basis,
5748	+	LongBinaryOperator reducer) {
5749	+	super(p, b, i, f, t); this.nextRight = nextRight;
5750	+	this.transformer = transformer;
5751	+	this.basis = basis; this.reducer = reducer;
5752	+	}
5753	+	public final Long getRawResult() { return result; }
5754	+	public final void compute() {
5755	+	final ToLongFunction<? super V> transformer;
5756	+	final LongBinaryOperator reducer;
5757	+	if ((transformer = this.transformer) != null &&
5758	+	(reducer = this.reducer) != null) {
5759	+	long r = this.basis;
5760	+	for (int i = baseIndex, f, h; batch > 0 &&
5761	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5762	+	addToPendingCount(1);
5763	+	(rights = new MapReduceValuesToLongTask<K,V>
5764	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5765	+	rights, transformer, r, reducer)).fork();
5766	+	}
5767	+	for (Node<K,V> p; (p = advance()) != null; )
5768	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5769	+	result = r;
5770	+	CountedCompleter<?> c;
5771	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5772	+	@SuppressWarnings("unchecked") MapReduceValuesToLongTask<K,V>
5773	+	t = (MapReduceValuesToLongTask<K,V>)c,
5774	+	s = t.rights;
5775	+	while (s != null) {
5776	+	t.result = reducer.applyAsLong(t.result, s.result);
5777	+	s = t.rights = s.nextRight;
5778	+	}
5779	+	}
5780	+	}
5781	+	}
5782		}
5783
5784	<	/* ---------------- Serialization Support -------------- */
5784	>	@SuppressWarnings("serial")
5785	>	static final class MapReduceEntriesToLongTask<K,V>
5786	>	extends BulkTask<K,V,Long> {
5787	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5788	>	final LongBinaryOperator reducer;
5789	>	final long basis;
5790	>	long result;
5791	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5792	>	MapReduceEntriesToLongTask
5793	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5794	>	MapReduceEntriesToLongTask<K,V> nextRight,
5795	>	ToLongFunction<Map.Entry<K,V>> transformer,
5796	>	long basis,
5797	>	LongBinaryOperator reducer) {
5798	>	super(p, b, i, f, t); this.nextRight = nextRight;
5799	>	this.transformer = transformer;
5800	>	this.basis = basis; this.reducer = reducer;
5801	>	}
5802	>	public final Long getRawResult() { return result; }
5803	>	public final void compute() {
5804	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5805	>	final LongBinaryOperator reducer;
5806	>	if ((transformer = this.transformer) != null &&
5807	>	(reducer = this.reducer) != null) {
5808	>	long r = this.basis;
5809	>	for (int i = baseIndex, f, h; batch > 0 &&
5810	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5811	>	addToPendingCount(1);
5812	>	(rights = new MapReduceEntriesToLongTask<K,V>
5813	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5814	>	rights, transformer, r, reducer)).fork();
5815	>	}
5816	>	for (Node<K,V> p; (p = advance()) != null; )
5817	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
5818	>	result = r;
5819	>	CountedCompleter<?> c;
5820	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5821	>	@SuppressWarnings("unchecked") MapReduceEntriesToLongTask<K,V>
5822	>	t = (MapReduceEntriesToLongTask<K,V>)c,
5823	>	s = t.rights;
5824	>	while (s != null) {
5825	>	t.result = reducer.applyAsLong(t.result, s.result);
5826	>	s = t.rights = s.nextRight;
5827	>	}
5828	>	}
5829	>	}
5830	>	}
5831	>	}
5832
5833	<	/**
5834	<	* Save the state of the <tt>ConcurrentHashMap</tt>
5835	<	* instance to a stream (i.e.,
5836	<	* serialize it).
5837	<	* @param s the stream
5838	<	* @serialData
5839	<	* the key (Object) and value (Object)
5840	<	* for each key-value mapping, followed by a null pair.
5841	<	* The key-value mappings are emitted in no particular order.
5842	<	*/
5843	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
5844	<	s.defaultWriteObject();
5833	>	@SuppressWarnings("serial")
5834	>	static final class MapReduceMappingsToLongTask<K,V>
5835	>	extends BulkTask<K,V,Long> {
5836	>	final ToLongBiFunction<? super K, ? super V> transformer;
5837	>	final LongBinaryOperator reducer;
5838	>	final long basis;
5839	>	long result;
5840	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
5841	>	MapReduceMappingsToLongTask
5842	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5843	>	MapReduceMappingsToLongTask<K,V> nextRight,
5844	>	ToLongBiFunction<? super K, ? super V> transformer,
5845	>	long basis,
5846	>	LongBinaryOperator reducer) {
5847	>	super(p, b, i, f, t); this.nextRight = nextRight;
5848	>	this.transformer = transformer;
5849	>	this.basis = basis; this.reducer = reducer;
5850	>	}
5851	>	public final Long getRawResult() { return result; }
5852	>	public final void compute() {
5853	>	final ToLongBiFunction<? super K, ? super V> transformer;
5854	>	final LongBinaryOperator reducer;
5855	>	if ((transformer = this.transformer) != null &&
5856	>	(reducer = this.reducer) != null) {
5857	>	long r = this.basis;
5858	>	for (int i = baseIndex, f, h; batch > 0 &&
5859	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5860	>	addToPendingCount(1);
5861	>	(rights = new MapReduceMappingsToLongTask<K,V>
5862	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5863	>	rights, transformer, r, reducer)).fork();
5864	>	}
5865	>	for (Node<K,V> p; (p = advance()) != null; )
5866	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
5867	>	result = r;
5868	>	CountedCompleter<?> c;
5869	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5870	>	@SuppressWarnings("unchecked") MapReduceMappingsToLongTask<K,V>
5871	>	t = (MapReduceMappingsToLongTask<K,V>)c,
5872	>	s = t.rights;
5873	>	while (s != null) {
5874	>	t.result = reducer.applyAsLong(t.result, s.result);
5875	>	s = t.rights = s.nextRight;
5876	>	}
5877	>	}
5878	>	}
5879	>	}
5880	>	}
5881
5882	<	for (int k = 0; k < segments.length; ++k) {
5883	<	Segment<K,V> seg = (Segment<K,V>)segments[k];
5884	<	seg.lock();
5885	<	try {
5886	<	HashEntry[] tab = seg.table;
5887	<	for (int i = 0; i < tab.length; ++i) {
5888	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i]; e != null; e = e.next) {
5889	<	s.writeObject(e.key);
5890	<	s.writeObject(e.value);
5882	>	@SuppressWarnings("serial")
5883	>	static final class MapReduceKeysToIntTask<K,V>
5884	>	extends BulkTask<K,V,Integer> {
5885	>	final ToIntFunction<? super K> transformer;
5886	>	final IntBinaryOperator reducer;
5887	>	final int basis;
5888	>	int result;
5889	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
5890	>	MapReduceKeysToIntTask
5891	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5892	>	MapReduceKeysToIntTask<K,V> nextRight,
5893	>	ToIntFunction<? super K> transformer,
5894	>	int basis,
5895	>	IntBinaryOperator reducer) {
5896	>	super(p, b, i, f, t); this.nextRight = nextRight;
5897	>	this.transformer = transformer;
5898	>	this.basis = basis; this.reducer = reducer;
5899	>	}
5900	>	public final Integer getRawResult() { return result; }
5901	>	public final void compute() {
5902	>	final ToIntFunction<? super K> transformer;
5903	>	final IntBinaryOperator reducer;
5904	>	if ((transformer = this.transformer) != null &&
5905	>	(reducer = this.reducer) != null) {
5906	>	int r = this.basis;
5907	>	for (int i = baseIndex, f, h; batch > 0 &&
5908	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5909	>	addToPendingCount(1);
5910	>	(rights = new MapReduceKeysToIntTask<K,V>
5911	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5912	>	rights, transformer, r, reducer)).fork();
5913	>	}
5914	>	for (Node<K,V> p; (p = advance()) != null; )
5915	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
5916	>	result = r;
5917	>	CountedCompleter<?> c;
5918	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5919	>	@SuppressWarnings("unchecked") MapReduceKeysToIntTask<K,V>
5920	>	t = (MapReduceKeysToIntTask<K,V>)c,
5921	>	s = t.rights;
5922	>	while (s != null) {
5923	>	t.result = reducer.applyAsInt(t.result, s.result);
5924	>	s = t.rights = s.nextRight;
5925		}
5926		}
1356	–	} finally {
1357	–	seg.unlock();
5927		}
5928		}
1360	–	s.writeObject(null);
1361	–	s.writeObject(null);
5929		}
5930
5931	<	/**
5932	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
5933	<	* instance from a stream (i.e.,
5934	<	* deserialize it).
5935	<	* @param s the stream
5936	<	*/
5937	<	private void readObject(java.io.ObjectInputStream s)
5938	<	throws IOException, ClassNotFoundException  {
5939	<	s.defaultReadObject();
5931	>	@SuppressWarnings("serial")
5932	>	static final class MapReduceValuesToIntTask<K,V>
5933	>	extends BulkTask<K,V,Integer> {
5934	>	final ToIntFunction<? super V> transformer;
5935	>	final IntBinaryOperator reducer;
5936	>	final int basis;
5937	>	int result;
5938	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
5939	>	MapReduceValuesToIntTask
5940	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5941	>	MapReduceValuesToIntTask<K,V> nextRight,
5942	>	ToIntFunction<? super V> transformer,
5943	>	int basis,
5944	>	IntBinaryOperator reducer) {
5945	>	super(p, b, i, f, t); this.nextRight = nextRight;
5946	>	this.transformer = transformer;
5947	>	this.basis = basis; this.reducer = reducer;
5948	>	}
5949	>	public final Integer getRawResult() { return result; }
5950	>	public final void compute() {
5951	>	final ToIntFunction<? super V> transformer;
5952	>	final IntBinaryOperator reducer;
5953	>	if ((transformer = this.transformer) != null &&
5954	>	(reducer = this.reducer) != null) {
5955	>	int r = this.basis;
5956	>	for (int i = baseIndex, f, h; batch > 0 &&
5957	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5958	>	addToPendingCount(1);
5959	>	(rights = new MapReduceValuesToIntTask<K,V>
5960	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5961	>	rights, transformer, r, reducer)).fork();
5962	>	}
5963	>	for (Node<K,V> p; (p = advance()) != null; )
5964	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
5965	>	result = r;
5966	>	CountedCompleter<?> c;
5967	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5968	>	@SuppressWarnings("unchecked") MapReduceValuesToIntTask<K,V>
5969	>	t = (MapReduceValuesToIntTask<K,V>)c,
5970	>	s = t.rights;
5971	>	while (s != null) {
5972	>	t.result = reducer.applyAsInt(t.result, s.result);
5973	>	s = t.rights = s.nextRight;
5974	>	}
5975	>	}
5976	>	}
5977	>	}
5978	>	}
5979
5980	<	// Initialize each segment to be minimally sized, and let grow.
5981	<	for (int i = 0; i < segments.length; ++i) {
5982	<	segments[i].setTable(new HashEntry[1]);
5980	>	@SuppressWarnings("serial")
5981	>	static final class MapReduceEntriesToIntTask<K,V>
5982	>	extends BulkTask<K,V,Integer> {
5983	>	final ToIntFunction<Map.Entry<K,V>> transformer;
5984	>	final IntBinaryOperator reducer;
5985	>	final int basis;
5986	>	int result;
5987	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
5988	>	MapReduceEntriesToIntTask
5989	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5990	>	MapReduceEntriesToIntTask<K,V> nextRight,
5991	>	ToIntFunction<Map.Entry<K,V>> transformer,
5992	>	int basis,
5993	>	IntBinaryOperator reducer) {
5994	>	super(p, b, i, f, t); this.nextRight = nextRight;
5995	>	this.transformer = transformer;
5996	>	this.basis = basis; this.reducer = reducer;
5997	>	}
5998	>	public final Integer getRawResult() { return result; }
5999	>	public final void compute() {
6000	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6001	>	final IntBinaryOperator reducer;
6002	>	if ((transformer = this.transformer) != null &&
6003	>	(reducer = this.reducer) != null) {
6004	>	int r = this.basis;
6005	>	for (int i = baseIndex, f, h; batch > 0 &&
6006	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6007	>	addToPendingCount(1);
6008	>	(rights = new MapReduceEntriesToIntTask<K,V>
6009	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6010	>	rights, transformer, r, reducer)).fork();
6011	>	}
6012	>	for (Node<K,V> p; (p = advance()) != null; )
6013	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6014	>	result = r;
6015	>	CountedCompleter<?> c;
6016	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6017	>	@SuppressWarnings("unchecked") MapReduceEntriesToIntTask<K,V>
6018	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6019	>	s = t.rights;
6020	>	while (s != null) {
6021	>	t.result = reducer.applyAsInt(t.result, s.result);
6022	>	s = t.rights = s.nextRight;
6023	>	}
6024	>	}
6025	>	}
6026		}
6027	+	}
6028
6029	<	// Read the keys and values, and put the mappings in the table
6030	<	for (;;) {
6031	<	K key = (K) s.readObject();
6032	<	V value = (V) s.readObject();
6033	<	if (key == null)
6034	<	break;
6035	<	put(key, value);
6029	>	@SuppressWarnings("serial")
6030	>	static final class MapReduceMappingsToIntTask<K,V>
6031	>	extends BulkTask<K,V,Integer> {
6032	>	final ToIntBiFunction<? super K, ? super V> transformer;
6033	>	final IntBinaryOperator reducer;
6034	>	final int basis;
6035	>	int result;
6036	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6037	>	MapReduceMappingsToIntTask
6038	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6039	>	MapReduceMappingsToIntTask<K,V> nextRight,
6040	>	ToIntBiFunction<? super K, ? super V> transformer,
6041	>	int basis,
6042	>	IntBinaryOperator reducer) {
6043	>	super(p, b, i, f, t); this.nextRight = nextRight;
6044	>	this.transformer = transformer;
6045	>	this.basis = basis; this.reducer = reducer;
6046	>	}
6047	>	public final Integer getRawResult() { return result; }
6048	>	public final void compute() {
6049	>	final ToIntBiFunction<? super K, ? super V> transformer;
6050	>	final IntBinaryOperator reducer;
6051	>	if ((transformer = this.transformer) != null &&
6052	>	(reducer = this.reducer) != null) {
6053	>	int r = this.basis;
6054	>	for (int i = baseIndex, f, h; batch > 0 &&
6055	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6056	>	addToPendingCount(1);
6057	>	(rights = new MapReduceMappingsToIntTask<K,V>
6058	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6059	>	rights, transformer, r, reducer)).fork();
6060	>	}
6061	>	for (Node<K,V> p; (p = advance()) != null; )
6062	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6063	>	result = r;
6064	>	CountedCompleter<?> c;
6065	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6066	>	@SuppressWarnings("unchecked") MapReduceMappingsToIntTask<K,V>
6067	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6068	>	s = t.rights;
6069	>	while (s != null) {
6070	>	t.result = reducer.applyAsInt(t.result, s.result);
6071	>	s = t.rights = s.nextRight;
6072	>	}
6073	>	}
6074	>	}
6075		}
6076		}
1388	–	}
6077
6078	+	// Unsafe mechanics
6079	+	private static final sun.misc.Unsafe U;
6080	+	private static final long SIZECTL;
6081	+	private static final long TRANSFERINDEX;
6082	+	private static final long TRANSFERORIGIN;
6083	+	private static final long BASECOUNT;
6084	+	private static final long CELLSBUSY;
6085	+	private static final long CELLVALUE;
6086	+	private static final long ABASE;
6087	+	private static final int ASHIFT;
6088	+
6089	+	static {
6090	+	try {
6091	+	U = sun.misc.Unsafe.getUnsafe();
6092	+	Class<?> k = ConcurrentHashMap.class;
6093	+	SIZECTL = U.objectFieldOffset
6094	+	(k.getDeclaredField("sizeCtl"));
6095	+	TRANSFERINDEX = U.objectFieldOffset
6096	+	(k.getDeclaredField("transferIndex"));
6097	+	TRANSFERORIGIN = U.objectFieldOffset
6098	+	(k.getDeclaredField("transferOrigin"));
6099	+	BASECOUNT = U.objectFieldOffset
6100	+	(k.getDeclaredField("baseCount"));
6101	+	CELLSBUSY = U.objectFieldOffset
6102	+	(k.getDeclaredField("cellsBusy"));
6103	+	Class<?> ck = CounterCell.class;
6104	+	CELLVALUE = U.objectFieldOffset
6105	+	(ck.getDeclaredField("value"));
6106	+	Class<?> ak = Node[].class;
6107	+	ABASE = U.arrayBaseOffset(ak);
6108	+	int scale = U.arrayIndexScale(ak);
6109	+	if ((scale & (scale - 1)) != 0)
6110	+	throw new Error("data type scale not a power of two");
6111	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6112	+	} catch (Exception e) {
6113	+	throw new Error(e);
6114	+	}
6115	+	}
6116	+	}

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