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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.83 by jsr166, Mon Aug 22 03:42:10 2005 UTC vs.
Revision 1.295 by jsr166, Sun Jul 17 04:23:31 2016 UTC

#	Line 1 | Line 1
1		/*
2		* Written by Doug Lea with assistance from members of JCP JSR-166
3		* Expert Group and released to the public domain, 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.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.atomic.AtomicReference;
25	>	import java.util.concurrent.locks.LockSupport;
26	>	import java.util.concurrent.locks.ReentrantLock;
27	>	import java.util.function.BiConsumer;
28	>	import java.util.function.BiFunction;
29	>	import java.util.function.Consumer;
30	>	import java.util.function.DoubleBinaryOperator;
31	>	import java.util.function.Function;
32	>	import java.util.function.IntBinaryOperator;
33	>	import java.util.function.LongBinaryOperator;
34	>	import java.util.function.Predicate;
35	>	import java.util.function.ToDoubleBiFunction;
36	>	import java.util.function.ToDoubleFunction;
37	>	import java.util.function.ToIntBiFunction;
38	>	import java.util.function.ToIntFunction;
39	>	import java.util.function.ToLongBiFunction;
40	>	import java.util.function.ToLongFunction;
41	>	import java.util.stream.Stream;
42	>	import jdk.internal.misc.Unsafe;
43
44		/**
45		* A hash table supporting full concurrency of retrievals and
46	<	* adjustable expected concurrency for updates. This class obeys the
46	>	* high expected concurrency for updates. This class obeys the
47		* same functional specification as {@link java.util.Hashtable}, and
48		* includes versions of methods corresponding to each method of
49	<	* <tt>Hashtable</tt>. However, even though all operations are
49	>	* {@code Hashtable}. However, even though all operations are
50		* thread-safe, retrieval operations do <em>not</em> entail locking,
51		* and there is <em>not</em> any support for locking the entire table
52		* in a way that prevents all access.  This class is fully
53	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
53	>	* interoperable with {@code Hashtable} in programs that rely on its
54		* thread safety but not on its synchronization details.
55		*
56	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
57	<	* block, so may overlap with update operations (including
58	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
59	<	* of the most recently <em>completed</em> update operations holding
60	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
61	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
62	<	* removal of only some entries.  Similarly, Iterators and
63	<	* Enumerations return elements reflecting the state of the hash table
64	<	* at some point at or since the creation of the iterator/enumeration.
65	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
56	>	* <p>Retrieval operations (including {@code get}) generally do not
57	>	* block, so may overlap with update operations (including {@code put}
58	>	* and {@code remove}). Retrievals reflect the results of the most
59	>	* recently <em>completed</em> update operations holding upon their
60	>	* onset. (More formally, an update operation for a given key bears a
61	>	* <em>happens-before</em> relation with any (non-null) retrieval for
62	>	* that key reporting the updated value.)  For aggregate operations
63	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
64	>	* reflect insertion or removal of only some entries.  Similarly,
65	>	* Iterators, Spliterators and Enumerations return elements reflecting the
66	>	* state of the hash table at some point at or since the creation of the
67	>	* iterator/enumeration.  They do <em>not</em> throw {@link
68	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
69		* However, iterators are designed to be used by only one thread at a time.
70	+	* Bear in mind that the results of aggregate status methods including
71	+	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
72	+	* useful only when a map is not undergoing concurrent updates in other threads.
73	+	* Otherwise the results of these methods reflect transient states
74	+	* that may be adequate for monitoring or estimation purposes, but not
75	+	* for program control.
76	+	*
77	+	* <p>The table is dynamically expanded when there are too many
78	+	* collisions (i.e., keys that have distinct hash codes but fall into
79	+	* the same slot modulo the table size), with the expected average
80	+	* effect of maintaining roughly two bins per mapping (corresponding
81	+	* to a 0.75 load factor threshold for resizing). There may be much
82	+	* variance around this average as mappings are added and removed, but
83	+	* overall, this maintains a commonly accepted time/space tradeoff for
84	+	* hash tables.  However, resizing this or any other kind of hash
85	+	* table may be a relatively slow operation. When possible, it is a
86	+	* good idea to provide a size estimate as an optional {@code
87	+	* initialCapacity} constructor argument. An additional optional
88	+	* {@code loadFactor} constructor argument provides a further means of
89	+	* customizing initial table capacity by specifying the table density
90	+	* to be used in calculating the amount of space to allocate for the
91	+	* given number of elements.  Also, for compatibility with previous
92	+	* versions of this class, constructors may optionally specify an
93	+	* expected {@code concurrencyLevel} as an additional hint for
94	+	* internal sizing.  Note that using many keys with exactly the same
95	+	* {@code hashCode()} is a sure way to slow down performance of any
96	+	* hash table. To ameliorate impact, when keys are {@link Comparable},
97	+	* this class may use comparison order among keys to help break ties.
98	+	*
99	+	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
100	+	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
101	+	* (using {@link #keySet(Object)} when only keys are of interest, and the
102	+	* mapped values are (perhaps transiently) not used or all take the
103	+	* same mapping value.
104		*
105	<	* <p> The allowed concurrency among update operations is guided by
106	<	* the optional <tt>concurrencyLevel</tt> constructor argument
107	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
108	<	* table is internally partitioned to try to permit the indicated
109	<	* number of concurrent updates without contention. Because placement
110	<	* in hash tables is essentially random, the actual concurrency will
45	<	* vary.  Ideally, you should choose a value to accommodate as many
46	<	* threads as will ever concurrently modify the table. Using a
47	<	* significantly higher value than you need can waste space and time,
48	<	* and a significantly lower value can lead to thread contention. But
49	<	* overestimates and underestimates within an order of magnitude do
50	<	* not usually have much noticeable impact. A value of one is
51	<	* appropriate when it is known that only one thread will modify and
52	<	* all others will only read. Also, resizing this or any other kind of
53	<	* hash table is a relatively slow operation, so, when possible, it is
54	<	* a good idea to provide estimates of expected table sizes in
55	<	* constructors.
105	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
106	>	* form of histogram or multiset) by using {@link
107	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
108	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
109	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
110	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
111		*
112		* <p>This class and its views and iterators implement all of the
113		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
114		* interfaces.
115		*
116	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
117	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
116	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
117	>	* does <em>not</em> allow {@code null} to be used as a key or value.
118	>	*
119	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
120	>	* operations that, unlike most {@link Stream} methods, are designed
121	>	* to be safely, and often sensibly, applied even with maps that are
122	>	* being concurrently updated by other threads; for example, when
123	>	* computing a snapshot summary of the values in a shared registry.
124	>	* There are three kinds of operation, each with four forms, accepting
125	>	* functions with keys, values, entries, and (key, value) pairs as
126	>	* arguments and/or return values. Because the elements of a
127	>	* ConcurrentHashMap are not ordered in any particular way, and may be
128	>	* processed in different orders in different parallel executions, the
129	>	* correctness of supplied functions should not depend on any
130	>	* ordering, or on any other objects or values that may transiently
131	>	* change while computation is in progress; and except for forEach
132	>	* actions, should ideally be side-effect-free. Bulk operations on
133	>	* {@link java.util.Map.Entry} objects do not support method {@code
134	>	* setValue}.
135	>	*
136	>	* <ul>
137	>	* <li>forEach: Performs a given action on each element.
138	>	* A variant form applies a given transformation on each element
139	>	* before performing the action.
140	>	*
141	>	* <li>search: Returns the first available non-null result of
142	>	* applying a given function on each element; skipping further
143	>	* search when a result is found.
144	>	*
145	>	* <li>reduce: Accumulates each element.  The supplied reduction
146	>	* function cannot rely on ordering (more formally, it should be
147	>	* both associative and commutative).  There are five variants:
148	>	*
149	>	* <ul>
150	>	*
151	>	* <li>Plain reductions. (There is not a form of this method for
152	>	* (key, value) function arguments since there is no corresponding
153	>	* return type.)
154	>	*
155	>	* <li>Mapped reductions that accumulate the results of a given
156	>	* function applied to each element.
157	>	*
158	>	* <li>Reductions to scalar doubles, longs, and ints, using a
159	>	* given basis value.
160	>	*
161	>	* </ul>
162	>	* </ul>
163	>	*
164	>	* <p>These bulk operations accept a {@code parallelismThreshold}
165	>	* argument. Methods proceed sequentially if the current map size is
166	>	* estimated to be less than the given threshold. Using a value of
167	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
168	>	* of {@code 1} results in maximal parallelism by partitioning into
169	>	* enough subtasks to fully utilize the {@link
170	>	* ForkJoinPool#commonPool()} that is used for all parallel
171	>	* computations. Normally, you would initially choose one of these
172	>	* extreme values, and then measure performance of using in-between
173	>	* values that trade off overhead versus throughput.
174	>	*
175	>	* <p>The concurrency properties of bulk operations follow
176	>	* from those of ConcurrentHashMap: Any non-null result returned
177	>	* from {@code get(key)} and related access methods bears a
178	>	* happens-before relation with the associated insertion or
179	>	* update.  The result of any bulk operation reflects the
180	>	* composition of these per-element relations (but is not
181	>	* necessarily atomic with respect to the map as a whole unless it
182	>	* is somehow known to be quiescent).  Conversely, because keys
183	>	* and values in the map are never null, null serves as a reliable
184	>	* atomic indicator of the current lack of any result.  To
185	>	* maintain this property, null serves as an implicit basis for
186	>	* all non-scalar reduction operations. For the double, long, and
187	>	* int versions, the basis should be one that, when combined with
188	>	* any other value, returns that other value (more formally, it
189	>	* should be the identity element for the reduction). Most common
190	>	* reductions have these properties; for example, computing a sum
191	>	* with basis 0 or a minimum with basis MAX_VALUE.
192	>	*
193	>	* <p>Search and transformation functions provided as arguments
194	>	* should similarly return null to indicate the lack of any result
195	>	* (in which case it is not used). In the case of mapped
196	>	* reductions, this also enables transformations to serve as
197	>	* filters, returning null (or, in the case of primitive
198	>	* specializations, the identity basis) if the element should not
199	>	* be combined. You can create compound transformations and
200	>	* filterings by composing them yourself under this "null means
201	>	* there is nothing there now" rule before using them in search or
202	>	* reduce operations.
203	>	*
204	>	* <p>Methods accepting and/or returning Entry arguments maintain
205	>	* key-value associations. They may be useful for example when
206	>	* finding the key for the greatest value. Note that "plain" Entry
207	>	* arguments can be supplied using {@code new
208	>	* AbstractMap.SimpleEntry(k,v)}.
209	>	*
210	>	* <p>Bulk operations may complete abruptly, throwing an
211	>	* exception encountered in the application of a supplied
212	>	* function. Bear in mind when handling such exceptions that other
213	>	* concurrently executing functions could also have thrown
214	>	* exceptions, or would have done so if the first exception had
215	>	* not occurred.
216	>	*
217	>	* <p>Speedups for parallel compared to sequential forms are common
218	>	* but not guaranteed.  Parallel operations involving brief functions
219	>	* on small maps may execute more slowly than sequential forms if the
220	>	* underlying work to parallelize the computation is more expensive
221	>	* than the computation itself.  Similarly, parallelization may not
222	>	* lead to much actual parallelism if all processors are busy
223	>	* performing unrelated tasks.
224	>	*
225	>	* <p>All arguments to all task methods must be non-null.
226		*
227		* <p>This class is a member of the
228	<	* <a href="{@docRoot}/../guide/collections/index.html">
228	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
229		* Java Collections Framework</a>.
230		*
231		* @since 1.5
#	Line 70 | Line 233 | import java.io.ObjectOutputStream;
233		* @param <K> the type of keys maintained by this map
234		* @param <V> the type of mapped values
235		*/
236	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
237	<	implements ConcurrentMap<K, V>, Serializable {
236	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
237	>	implements ConcurrentMap<K,V>, Serializable {
238		private static final long serialVersionUID = 7249069246763182397L;
239
240		/*
241	<	* The basic strategy is to subdivide the table among Segments,
242	<	* each of which itself is a concurrently readable hash table.
241	>	* Overview:
242	>	*
243	>	* The primary design goal of this hash table is to maintain
244	>	* concurrent readability (typically method get(), but also
245	>	* iterators and related methods) while minimizing update
246	>	* contention. Secondary goals are to keep space consumption about
247	>	* the same or better than java.util.HashMap, and to support high
248	>	* initial insertion rates on an empty table by many threads.
249	>	*
250	>	* This map usually acts as a binned (bucketed) hash table.  Each
251	>	* key-value mapping is held in a Node.  Most nodes are instances
252	>	* of the basic Node class with hash, key, value, and next
253	>	* fields. However, various subclasses exist: TreeNodes are
254	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
255	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
256	>	* of bins during resizing. ReservationNodes are used as
257	>	* placeholders while establishing values in computeIfAbsent and
258	>	* related methods.  The types TreeBin, ForwardingNode, and
259	>	* ReservationNode do not hold normal user keys, values, or
260	>	* hashes, and are readily distinguishable during search etc
261	>	* because they have negative hash fields and null key and value
262	>	* fields. (These special nodes are either uncommon or transient,
263	>	* so the impact of carrying around some unused fields is
264	>	* insignificant.)
265	>	*
266	>	* The table is lazily initialized to a power-of-two size upon the
267	>	* first insertion.  Each bin in the table normally contains a
268	>	* list of Nodes (most often, the list has only zero or one Node).
269	>	* Table accesses require volatile/atomic reads, writes, and
270	>	* CASes.  Because there is no other way to arrange this without
271	>	* adding further indirections, we use intrinsics
272	>	* (jdk.internal.misc.Unsafe) operations.
273	>	*
274	>	* We use the top (sign) bit of Node hash fields for control
275	>	* purposes -- it is available anyway because of addressing
276	>	* constraints.  Nodes with negative hash fields are specially
277	>	* handled or ignored in map methods.
278	>	*
279	>	* Insertion (via put or its variants) of the first node in an
280	>	* empty bin is performed by just CASing it to the bin.  This is
281	>	* by far the most common case for put operations under most
282	>	* key/hash distributions.  Other update operations (insert,
283	>	* delete, and replace) require locks.  We do not want to waste
284	>	* the space required to associate a distinct lock object with
285	>	* each bin, so instead use the first node of a bin list itself as
286	>	* a lock. Locking support for these locks relies on builtin
287	>	* "synchronized" monitors.
288	>	*
289	>	* Using the first node of a list as a lock does not by itself
290	>	* suffice though: When a node is locked, any update must first
291	>	* validate that it is still the first node after locking it, and
292	>	* retry if not. Because new nodes are always appended to lists,
293	>	* once a node is first in a bin, it remains first until deleted
294	>	* or the bin becomes invalidated (upon resizing).
295	>	*
296	>	* The main disadvantage of per-bin locks is that other update
297	>	* operations on other nodes in a bin list protected by the same
298	>	* lock can stall, for example when user equals() or mapping
299	>	* functions take a long time.  However, statistically, under
300	>	* random hash codes, this is not a common problem.  Ideally, the
301	>	* frequency of nodes in bins follows a Poisson distribution
302	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
303	>	* parameter of about 0.5 on average, given the resizing threshold
304	>	* of 0.75, although with a large variance because of resizing
305	>	* granularity. Ignoring variance, the expected occurrences of
306	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
307	>	* first values are:
308	>	*
309	>	* 0:    0.60653066
310	>	* 1:    0.30326533
311	>	* 2:    0.07581633
312	>	* 3:    0.01263606
313	>	* 4:    0.00157952
314	>	* 5:    0.00015795
315	>	* 6:    0.00001316
316	>	* 7:    0.00000094
317	>	* 8:    0.00000006
318	>	* more: less than 1 in ten million
319	>	*
320	>	* Lock contention probability for two threads accessing distinct
321	>	* elements is roughly 1 / (8 * #elements) under random hashes.
322	>	*
323	>	* Actual hash code distributions encountered in practice
324	>	* sometimes deviate significantly from uniform randomness.  This
325	>	* includes the case when N > (1<<30), so some keys MUST collide.
326	>	* Similarly for dumb or hostile usages in which multiple keys are
327	>	* designed to have identical hash codes or ones that differs only
328	>	* in masked-out high bits. So we use a secondary strategy that
329	>	* applies when the number of nodes in a bin exceeds a
330	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
331	>	* specialized form of red-black trees), bounding search time to
332	>	* O(log N).  Each search step in a TreeBin is at least twice as
333	>	* slow as in a regular list, but given that N cannot exceed
334	>	* (1<<64) (before running out of addresses) this bounds search
335	>	* steps, lock hold times, etc, to reasonable constants (roughly
336	>	* 100 nodes inspected per operation worst case) so long as keys
337	>	* are Comparable (which is very common -- String, Long, etc).
338	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
339	>	* traversal pointers as regular nodes, so can be traversed in
340	>	* iterators in the same way.
341	>	*
342	>	* The table is resized when occupancy exceeds a percentage
343	>	* threshold (nominally, 0.75, but see below).  Any thread
344	>	* noticing an overfull bin may assist in resizing after the
345	>	* initiating thread allocates and sets up the replacement array.
346	>	* However, rather than stalling, these other threads may proceed
347	>	* with insertions etc.  The use of TreeBins shields us from the
348	>	* worst case effects of overfilling while resizes are in
349	>	* progress.  Resizing proceeds by transferring bins, one by one,
350	>	* from the table to the next table. However, threads claim small
351	>	* blocks of indices to transfer (via field transferIndex) before
352	>	* doing so, reducing contention.  A generation stamp in field
353	>	* sizeCtl ensures that resizings do not overlap. Because we are
354	>	* using power-of-two expansion, the elements from each bin must
355	>	* either stay at same index, or move with a power of two
356	>	* offset. We eliminate unnecessary node creation by catching
357	>	* cases where old nodes can be reused because their next fields
358	>	* won't change.  On average, only about one-sixth of them need
359	>	* cloning when a table doubles. The nodes they replace will be
360	>	* garbage collectable as soon as they are no longer referenced by
361	>	* any reader thread that may be in the midst of concurrently
362	>	* traversing table.  Upon transfer, the old table bin contains
363	>	* only a special forwarding node (with hash field "MOVED") that
364	>	* contains the next table as its key. On encountering a
365	>	* forwarding node, access and update operations restart, using
366	>	* the new table.
367	>	*
368	>	* Each bin transfer requires its bin lock, which can stall
369	>	* waiting for locks while resizing. However, because other
370	>	* threads can join in and help resize rather than contend for
371	>	* locks, average aggregate waits become shorter as resizing
372	>	* progresses.  The transfer operation must also ensure that all
373	>	* accessible bins in both the old and new table are usable by any
374	>	* traversal.  This is arranged in part by proceeding from the
375	>	* last bin (table.length - 1) up towards the first.  Upon seeing
376	>	* a forwarding node, traversals (see class Traverser) arrange to
377	>	* move to the new table without revisiting nodes.  To ensure that
378	>	* no intervening nodes are skipped even when moved out of order,
379	>	* a stack (see class TableStack) is created on first encounter of
380	>	* a forwarding node during a traversal, to maintain its place if
381	>	* later processing the current table. The need for these
382	>	* save/restore mechanics is relatively rare, but when one
383	>	* forwarding node is encountered, typically many more will be.
384	>	* So Traversers use a simple caching scheme to avoid creating so
385	>	* many new TableStack nodes. (Thanks to Peter Levart for
386	>	* suggesting use of a stack here.)
387	>	*
388	>	* The traversal scheme also applies to partial traversals of
389	>	* ranges of bins (via an alternate Traverser constructor)
390	>	* to support partitioned aggregate operations.  Also, read-only
391	>	* operations give up if ever forwarded to a null table, which
392	>	* provides support for shutdown-style clearing, which is also not
393	>	* currently implemented.
394	>	*
395	>	* Lazy table initialization minimizes footprint until first use,
396	>	* and also avoids resizings when the first operation is from a
397	>	* putAll, constructor with map argument, or deserialization.
398	>	* These cases attempt to override the initial capacity settings,
399	>	* but harmlessly fail to take effect in cases of races.
400	>	*
401	>	* The element count is maintained using a specialization of
402	>	* LongAdder. We need to incorporate a specialization rather than
403	>	* just use a LongAdder in order to access implicit
404	>	* contention-sensing that leads to creation of multiple
405	>	* CounterCells.  The counter mechanics avoid contention on
406	>	* updates but can encounter cache thrashing if read too
407	>	* frequently during concurrent access. To avoid reading so often,
408	>	* resizing under contention is attempted only upon adding to a
409	>	* bin already holding two or more nodes. Under uniform hash
410	>	* distributions, the probability of this occurring at threshold
411	>	* is around 13%, meaning that only about 1 in 8 puts check
412	>	* threshold (and after resizing, many fewer do so).
413	>	*
414	>	* TreeBins use a special form of comparison for search and
415	>	* related operations (which is the main reason we cannot use
416	>	* existing collections such as TreeMaps). TreeBins contain
417	>	* Comparable elements, but may contain others, as well as
418	>	* elements that are Comparable but not necessarily Comparable for
419	>	* the same T, so we cannot invoke compareTo among them. To handle
420	>	* this, the tree is ordered primarily by hash value, then by
421	>	* Comparable.compareTo order if applicable.  On lookup at a node,
422	>	* if elements are not comparable or compare as 0 then both left
423	>	* and right children may need to be searched in the case of tied
424	>	* hash values. (This corresponds to the full list search that
425	>	* would be necessary if all elements were non-Comparable and had
426	>	* tied hashes.) On insertion, to keep a total ordering (or as
427	>	* close as is required here) across rebalancings, we compare
428	>	* classes and identityHashCodes as tie-breakers. The red-black
429	>	* balancing code is updated from pre-jdk-collections
430	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
431	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
432	>	* Algorithms" (CLR).
433	>	*
434	>	* TreeBins also require an additional locking mechanism.  While
435	>	* list traversal is always possible by readers even during
436	>	* updates, tree traversal is not, mainly because of tree-rotations
437	>	* that may change the root node and/or its linkages.  TreeBins
438	>	* include a simple read-write lock mechanism parasitic on the
439	>	* main bin-synchronization strategy: Structural adjustments
440	>	* associated with an insertion or removal are already bin-locked
441	>	* (and so cannot conflict with other writers) but must wait for
442	>	* ongoing readers to finish. Since there can be only one such
443	>	* waiter, we use a simple scheme using a single "waiter" field to
444	>	* block writers.  However, readers need never block.  If the root
445	>	* lock is held, they proceed along the slow traversal path (via
446	>	* next-pointers) until the lock becomes available or the list is
447	>	* exhausted, whichever comes first. These cases are not fast, but
448	>	* maximize aggregate expected throughput.
449	>	*
450	>	* Maintaining API and serialization compatibility with previous
451	>	* versions of this class introduces several oddities. Mainly: We
452	>	* leave untouched but unused constructor arguments referring to
453	>	* concurrencyLevel. We accept a loadFactor constructor argument,
454	>	* but apply it only to initial table capacity (which is the only
455	>	* time that we can guarantee to honor it.) We also declare an
456	>	* unused "Segment" class that is instantiated in minimal form
457	>	* only when serializing.
458	>	*
459	>	* Also, solely for compatibility with previous versions of this
460	>	* class, it extends AbstractMap, even though all of its methods
461	>	* are overridden, so it is just useless baggage.
462	>	*
463	>	* This file is organized to make things a little easier to follow
464	>	* while reading than they might otherwise: First the main static
465	>	* declarations and utilities, then fields, then main public
466	>	* methods (with a few factorings of multiple public methods into
467	>	* internal ones), then sizing methods, trees, traversers, and
468	>	* bulk operations.
469		*/
470
471		/* ---------------- Constants -------------- */
472
473		/**
474	<	* The default initial capacity for this table,
475	<	* used when not otherwise specified in a constructor.
474	>	* The largest possible table capacity.  This value must be
475	>	* exactly 1<<30 to stay within Java array allocation and indexing
476	>	* bounds for power of two table sizes, and is further required
477	>	* because the top two bits of 32bit hash fields are used for
478	>	* control purposes.
479		*/
480	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
480	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
481
482		/**
483	<	* The default load factor for this table, used when not
484	<	* otherwise specified in a constructor.
483	>	* The default initial table capacity.  Must be a power of 2
484	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
485		*/
486	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
486	>	private static final int DEFAULT_CAPACITY = 16;
487
488		/**
489	<	* The default concurrency level for this table, used when not
490	<	* otherwise specified in a constructor.
489	>	* The largest possible (non-power of two) array size.
490	>	* Needed by toArray and related methods.
491		*/
492	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
492	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
493
494		/**
495	<	* The maximum capacity, used if a higher value is implicitly
496	<	* specified by either of the constructors with arguments.  MUST
105	<	* be a power of two <= 1<<30 to ensure that entries are indexable
106	<	* using ints.
495	>	* The default concurrency level for this table. Unused but
496	>	* defined for compatibility with previous versions of this class.
497		*/
498	<	static final int MAXIMUM_CAPACITY = 1 << 30;
498	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
499
500		/**
501	<	* The maximum number of segments to allow; used to bound
502	<	* constructor arguments.
501	>	* The load factor for this table. Overrides of this value in
502	>	* constructors affect only the initial table capacity.  The
503	>	* actual floating point value isn't normally used -- it is
504	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
505	>	* the associated resizing threshold.
506		*/
507	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
507	>	private static final float LOAD_FACTOR = 0.75f;
508
509		/**
510	<	* Number of unsynchronized retries in size and containsValue
511	<	* methods before resorting to locking. This is used to avoid
512	<	* unbounded retries if tables undergo continuous modification
513	<	* which would make it impossible to obtain an accurate result.
510	>	* The bin count threshold for using a tree rather than list for a
511	>	* bin.  Bins are converted to trees when adding an element to a
512	>	* bin with at least this many nodes. The value must be greater
513	>	* than 2, and should be at least 8 to mesh with assumptions in
514	>	* tree removal about conversion back to plain bins upon
515	>	* shrinkage.
516		*/
517	<	static final int RETRIES_BEFORE_LOCK = 2;
123	<
124	<	/* ---------------- Fields -------------- */
517	>	static final int TREEIFY_THRESHOLD = 8;
518
519		/**
520	<	* Mask value for indexing into segments. The upper bits of a
521	<	* key's hash code are used to choose the segment.
520	>	* The bin count threshold for untreeifying a (split) bin during a
521	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
522	>	* most 6 to mesh with shrinkage detection under removal.
523		*/
524	<	final int segmentMask;
524	>	static final int UNTREEIFY_THRESHOLD = 6;
525
526		/**
527	<	* Shift value for indexing within segments.
527	>	* The smallest table capacity for which bins may be treeified.
528	>	* (Otherwise the table is resized if too many nodes in a bin.)
529	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
530	>	* conflicts between resizing and treeification thresholds.
531		*/
532	<	final int segmentShift;
532	>	static final int MIN_TREEIFY_CAPACITY = 64;
533
534		/**
535	<	* The segments, each of which is a specialized hash table
535	>	* Minimum number of rebinnings per transfer step. Ranges are
536	>	* subdivided to allow multiple resizer threads.  This value
537	>	* serves as a lower bound to avoid resizers encountering
538	>	* excessive memory contention.  The value should be at least
539	>	* DEFAULT_CAPACITY.
540		*/
541	<	final Segment<K,V>[] segments;
141	<
142	<	transient Set<K> keySet;
143	<	transient Set<Map.Entry<K,V>> entrySet;
144	<	transient Collection<V> values;
541	>	private static final int MIN_TRANSFER_STRIDE = 16;
542
543	<	/* ---------------- Small Utilities -------------- */
543	>	/**
544	>	* The number of bits used for generation stamp in sizeCtl.
545	>	* Must be at least 6 for 32bit arrays.
546	>	*/
547	>	private static final int RESIZE_STAMP_BITS = 16;
548
549		/**
550	<	* Returns a hash code for non-null Object x.
551	<	* Uses the same hash code spreader as most other java.util hash tables.
151	<	* @param x the object serving as a key
152	<	* @return the hash code
550	>	* The maximum number of threads that can help resize.
551	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
552		*/
553	<	static int hash(Object x) {
155	<	int h = x.hashCode();
156	<	h += ~(h << 9);
157	<	h ^=  (h >>> 14);
158	<	h +=  (h << 4);
159	<	h ^=  (h >>> 10);
160	<	return h;
161	<	}
553	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
554
555		/**
556	<	* Returns the segment that should be used for key with given hash
165	<	* @param hash the hash code for the key
166	<	* @return the segment
556	>	* The bit shift for recording size stamp in sizeCtl.
557		*/
558	<	final Segment<K,V> segmentFor(int hash) {
169	<	return segments[(hash >>> segmentShift) & segmentMask];
170	<	}
558	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
559
560	<	/* ---------------- Inner Classes -------------- */
560	>	/*
561	>	* Encodings for Node hash fields. See above for explanation.
562	>	*/
563	>	static final int MOVED     = -1; // hash for forwarding nodes
564	>	static final int TREEBIN   = -2; // hash for roots of trees
565	>	static final int RESERVED  = -3; // hash for transient reservations
566	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
567	>
568	>	/** Number of CPUS, to place bounds on some sizings */
569	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
570
571		/**
572	<	* ConcurrentHashMap list entry. Note that this is never exported
573	<	* out as a user-visible Map.Entry.
574	<	*
575	<	* Because the value field is volatile, not final, it is legal wrt
576	<	* the Java Memory Model for an unsynchronized reader to see null
577	<	* instead of initial value when read via a data race.  Although a
578	<	* reordering leading to this is not likely to ever actually
579	<	* occur, the Segment.readValueUnderLock method is used as a
580	<	* backup in case a null (pre-initialized) value is ever seen in
581	<	* an unsynchronized access method.
572	>	* Serialized pseudo-fields, provided only for jdk7 compatibility.
573	>	* @serialField segments Segment[]
574	>	*   The segments, each of which is a specialized hash table.
575	>	* @serialField segmentMask int
576	>	*   Mask value for indexing into segments. The upper bits of a
577	>	*   key's hash code are used to choose the segment.
578	>	* @serialField segmentShift int
579	>	*   Shift value for indexing within segments.
580	>	*/
581	>	private static final ObjectStreamField[] serialPersistentFields = {
582	>	new ObjectStreamField("segments", Segment[].class),
583	>	new ObjectStreamField("segmentMask", Integer.TYPE),
584	>	new ObjectStreamField("segmentShift", Integer.TYPE),
585	>	};
586	>
587	>	/* ---------------- Nodes -------------- */
588	>
589	>	/**
590	>	* Key-value entry.  This class is never exported out as a
591	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
592	>	* MapEntry below), but can be used for read-only traversals used
593	>	* in bulk tasks.  Subclasses of Node with a negative hash field
594	>	* are special, and contain null keys and values (but are never
595	>	* exported).  Otherwise, keys and vals are never null.
596		*/
597	<	static final class HashEntry<K,V> {
187	<	final K key;
597	>	static class Node<K,V> implements Map.Entry<K,V> {
598		final int hash;
599	<	volatile V value;
600	<	final HashEntry<K,V> next;
599	>	final K key;
600	>	volatile V val;
601	>	volatile Node<K,V> next;
602
603	<	HashEntry(K key, int hash, HashEntry<K,V> next, V value) {
193	<	this.key = key;
603	>	Node(int hash, K key, V val) {
604		this.hash = hash;
605	+	this.key = key;
606	+	this.val = val;
607	+	}
608	+
609	+	Node(int hash, K key, V val, Node<K,V> next) {
610	+	this(hash, key, val);
611		this.next = next;
196	–	this.value = value;
612		}
613
614	<	@SuppressWarnings("unchecked")
615	<	static final <K,V> HashEntry<K,V>[] newArray(int i) {
616	<	return new HashEntry[i];
617	<	}
614	>	public final K getKey()     { return key; }
615	>	public final V getValue()   { return val; }
616	>	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
617	>	public final String toString() {
618	>	return Helpers.mapEntryToString(key, val);
619	>	}
620	>	public final V setValue(V value) {
621	>	throw new UnsupportedOperationException();
622	>	}
623	>
624	>	public final boolean equals(Object o) {
625	>	Object k, v, u; Map.Entry<?,?> e;
626	>	return ((o instanceof Map.Entry) &&
627	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
628	>	(v = e.getValue()) != null &&
629	>	(k == key || k.equals(key)) &&
630	>	(v == (u = val) || v.equals(u)));
631	>	}
632	>
633	>	/**
634	>	* Virtualized support for map.get(); overridden in subclasses.
635	>	*/
636	>	Node<K,V> find(int h, Object k) {
637	>	Node<K,V> e = this;
638	>	if (k != null) {
639	>	do {
640	>	K ek;
641	>	if (e.hash == h &&
642	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
643	>	return e;
644	>	} while ((e = e.next) != null);
645	>	}
646	>	return null;
647	>	}
648		}
649
650	+	/* ---------------- Static utilities -------------- */
651	+
652		/**
653	<	* Segments are specialized versions of hash tables.  This
654	<	* subclasses from ReentrantLock opportunistically, just to
655	<	* simplify some locking and avoid separate construction.
653	>	* Spreads (XORs) higher bits of hash to lower and also forces top
654	>	* bit to 0. Because the table uses power-of-two masking, sets of
655	>	* hashes that vary only in bits above the current mask will
656	>	* always collide. (Among known examples are sets of Float keys
657	>	* holding consecutive whole numbers in small tables.)  So we
658	>	* apply a transform that spreads the impact of higher bits
659	>	* downward. There is a tradeoff between speed, utility, and
660	>	* quality of bit-spreading. Because many common sets of hashes
661	>	* are already reasonably distributed (so don't benefit from
662	>	* spreading), and because we use trees to handle large sets of
663	>	* collisions in bins, we just XOR some shifted bits in the
664	>	* cheapest possible way to reduce systematic lossage, as well as
665	>	* to incorporate impact of the highest bits that would otherwise
666	>	* never be used in index calculations because of table bounds.
667		*/
668	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
669	<	/*
670	<	* Segments maintain a table of entry lists that are ALWAYS
213	<	* kept in a consistent state, so can be read without locking.
214	<	* Next fields of nodes are immutable (final).  All list
215	<	* additions are performed at the front of each bin. This
216	<	* makes it easy to check changes, and also fast to traverse.
217	<	* When nodes would otherwise be changed, new nodes are
218	<	* created to replace them. This works well for hash tables
219	<	* since the bin lists tend to be short. (The average length
220	<	* is less than two for the default load factor threshold.)
221	<	*
222	<	* Read operations can thus proceed without locking, but rely
223	<	* on selected uses of volatiles to ensure that completed
224	<	* write operations performed by other threads are
225	<	* noticed. For most purposes, the "count" field, tracking the
226	<	* number of elements, serves as that volatile variable
227	<	* ensuring visibility.  This is convenient because this field
228	<	* needs to be read in many read operations anyway:
229	<	*
230	<	*   - All (unsynchronized) read operations must first read the
231	<	*     "count" field, and should not look at table entries if
232	<	*     it is 0.
233	<	*
234	<	*   - All (synchronized) write operations should write to
235	<	*     the "count" field after structurally changing any bin.
236	<	*     The operations must not take any action that could even
237	<	*     momentarily cause a concurrent read operation to see
238	<	*     inconsistent data. This is made easier by the nature of
239	<	*     the read operations in Map. For example, no operation
240	<	*     can reveal that the table has grown but the threshold
241	<	*     has not yet been updated, so there are no atomicity
242	<	*     requirements for this with respect to reads.
243	<	*
244	<	* As a guide, all critical volatile reads and writes to the
245	<	* count field are marked in code comments.
246	<	*/
668	>	static final int spread(int h) {
669	>	return (h ^ (h >>> 16)) & HASH_BITS;
670	>	}
671
672	<	private static final long serialVersionUID = 2249069246763182397L;
672	>	/**
673	>	* Returns a power of two table size for the given desired capacity.
674	>	* See Hackers Delight, sec 3.2
675	>	*/
676	>	private static final int tableSizeFor(int c) {
677	>	int n = c - 1;
678	>	n |= n >>> 1;
679	>	n |= n >>> 2;
680	>	n |= n >>> 4;
681	>	n |= n >>> 8;
682	>	n |= n >>> 16;
683	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
684	>	}
685
686	<	/**
687	<	* The number of elements in this segment's region.
688	<	*/
689	<	transient volatile int count;
686	>	/**
687	>	* Returns x's Class if it is of the form "class C implements
688	>	* Comparable<C>", else null.
689	>	*/
690	>	static Class<?> comparableClassFor(Object x) {
691	>	if (x instanceof Comparable) {
692	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
693	>	if ((c = x.getClass()) == String.class) // bypass checks
694	>	return c;
695	>	if ((ts = c.getGenericInterfaces()) != null) {
696	>	for (int i = 0; i < ts.length; ++i) {
697	>	if (((t = ts[i]) instanceof ParameterizedType) &&
698	>	((p = (ParameterizedType)t).getRawType() ==
699	>	Comparable.class) &&
700	>	(as = p.getActualTypeArguments()) != null &&
701	>	as.length == 1 && as[0] == c) // type arg is c
702	>	return c;
703	>	}
704	>	}
705	>	}
706	>	return null;
707	>	}
708
709	<	/**
710	<	* Number of updates that alter the size of the table. This is
711	<	* used during bulk-read methods to make sure they see a
712	<	* consistent snapshot: If modCounts change during a traversal
713	<	* of segments computing size or checking containsValue, then
714	<	* we might have an inconsistent view of state so (usually)
715	<	* must retry.
716	<	*/
717	<	transient int modCount;
709	>	/**
710	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
711	>	* class), else 0.
712	>	*/
713	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
714	>	static int compareComparables(Class<?> kc, Object k, Object x) {
715	>	return (x == null || x.getClass() != kc ? 0 :
716	>	((Comparable)k).compareTo(x));
717	>	}
718
719	<	/**
266	<	* The table is rehashed when its size exceeds this threshold.
267	<	* (The value of this field is always <tt>(int)(capacity *
268	<	* loadFactor)</tt>.)
269	<	*/
270	<	transient int threshold;
719	>	/* ---------------- Table element access -------------- */
720
721	<	/**
722	<	* The per-segment table.
723	<	*/
724	<	transient volatile HashEntry<K,V>[] table;
721	>	/*
722	>	* Atomic access methods are used for table elements as well as
723	>	* elements of in-progress next table while resizing.  All uses of
724	>	* the tab arguments must be null checked by callers.  All callers
725	>	* also paranoically precheck that tab's length is not zero (or an
726	>	* equivalent check), thus ensuring that any index argument taking
727	>	* the form of a hash value anded with (length - 1) is a valid
728	>	* index.  Note that, to be correct wrt arbitrary concurrency
729	>	* errors by users, these checks must operate on local variables,
730	>	* which accounts for some odd-looking inline assignments below.
731	>	* Note that calls to setTabAt always occur within locked regions,
732	>	* and so require only release ordering.
733	>	*/
734	>
735	>	@SuppressWarnings("unchecked")
736	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
737	>	return (Node<K,V>)U.getObjectAcquire(tab, ((long)i << ASHIFT) + ABASE);
738	>	}
739
740	<	/**
741	<	* The load factor for the hash table.  Even though this value
742	<	* is same for all segments, it is replicated to avoid needing
743	<	* links to outer object.
281	<	* @serial
282	<	*/
283	<	final float loadFactor;
740	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
741	>	Node<K,V> c, Node<K,V> v) {
742	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
743	>	}
744
745	<	Segment(int initialCapacity, float lf) {
746	<	loadFactor = lf;
747	<	setTable(HashEntry.<K,V>newArray(initialCapacity));
288	<	}
745	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
746	>	U.putObjectRelease(tab, ((long)i << ASHIFT) + ABASE, v);
747	>	}
748
749	<	@SuppressWarnings("unchecked")
291	<	static final <K,V> Segment<K,V>[] newArray(int i) {
292	<	return new Segment[i];
293	<	}
749	>	/* ---------------- Fields -------------- */
750
751	<	/**
752	<	* Sets table to new HashEntry array.
753	<	* Call only while holding lock or in constructor.
754	<	*/
755	<	void setTable(HashEntry<K,V>[] newTable) {
300	<	threshold = (int)(newTable.length * loadFactor);
301	<	table = newTable;
302	<	}
751	>	/**
752	>	* The array of bins. Lazily initialized upon first insertion.
753	>	* Size is always a power of two. Accessed directly by iterators.
754	>	*/
755	>	transient volatile Node<K,V>[] table;
756
757	<	/**
758	<	* Returns properly casted first entry of bin for given hash.
759	<	*/
760	<	HashEntry<K,V> getFirst(int hash) {
308	<	HashEntry<K,V>[] tab = table;
309	<	return tab[hash & (tab.length - 1)];
310	<	}
757	>	/**
758	>	* The next table to use; non-null only while resizing.
759	>	*/
760	>	private transient volatile Node<K,V>[] nextTable;
761
762	<	/**
763	<	* Reads value field of an entry under lock. Called if value
764	<	* field ever appears to be null. This is possible only if a
765	<	* compiler happens to reorder a HashEntry initialization with
766	<	* its table assignment, which is legal under memory model
767	<	* but is not known to ever occur.
318	<	*/
319	<	V readValueUnderLock(HashEntry<K,V> e) {
320	<	lock();
321	<	try {
322	<	return e.value;
323	<	} finally {
324	<	unlock();
325	<	}
326	<	}
762	>	/**
763	>	* Base counter value, used mainly when there is no contention,
764	>	* but also as a fallback during table initialization
765	>	* races. Updated via CAS.
766	>	*/
767	>	private transient volatile long baseCount;
768
769	<	/* Specialized implementations of map methods */
769	>	/**
770	>	* Table initialization and resizing control.  When negative, the
771	>	* table is being initialized or resized: -1 for initialization,
772	>	* else -(1 + the number of active resizing threads).  Otherwise,
773	>	* when table is null, holds the initial table size to use upon
774	>	* creation, or 0 for default. After initialization, holds the
775	>	* next element count value upon which to resize the table.
776	>	*/
777	>	private transient volatile int sizeCtl;
778
779	<	V get(Object key, int hash) {
780	<	if (count != 0) { // read-volatile
781	<	HashEntry<K,V> e = getFirst(hash);
782	<	while (e != null) {
334	<	if (e.hash == hash && key.equals(e.key)) {
335	<	V v = e.value;
336	<	if (v != null)
337	<	return v;
338	<	return readValueUnderLock(e); // recheck
339	<	}
340	<	e = e.next;
341	<	}
342	<	}
343	<	return null;
344	<	}
779	>	/**
780	>	* The next table index (plus one) to split while resizing.
781	>	*/
782	>	private transient volatile int transferIndex;
783
784	<	boolean containsKey(Object key, int hash) {
785	<	if (count != 0) { // read-volatile
786	<	HashEntry<K,V> e = getFirst(hash);
787	<	while (e != null) {
350	<	if (e.hash == hash && key.equals(e.key))
351	<	return true;
352	<	e = e.next;
353	<	}
354	<	}
355	<	return false;
356	<	}
784	>	/**
785	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
786	>	*/
787	>	private transient volatile int cellsBusy;
788
789	<	boolean containsValue(Object value) {
790	<	if (count != 0) { // read-volatile
791	<	HashEntry<K,V>[] tab = table;
792	<	int len = tab.length;
362	<	for (int i = 0 ; i < len; i++) {
363	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
364	<	V v = e.value;
365	<	if (v == null) // recheck
366	<	v = readValueUnderLock(e);
367	<	if (value.equals(v))
368	<	return true;
369	<	}
370	<	}
371	<	}
372	<	return false;
373	<	}
789	>	/**
790	>	* Table of counter cells. When non-null, size is a power of 2.
791	>	*/
792	>	private transient volatile CounterCell[] counterCells;
793
794	<	boolean replace(K key, int hash, V oldValue, V newValue) {
795	<	lock();
796	<	try {
797	<	HashEntry<K,V> e = getFirst(hash);
798	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
799	<	e = e.next;
800	<
801	<	boolean replaced = false;
802	<	if (e != null && oldValue.equals(e.value)) {
803	<	replaced = true;
804	<	e.value = newValue;
805	<	}
806	<	return replaced;
807	<	} finally {
808	<	unlock();
794	>	// views
795	>	private transient KeySetView<K,V> keySet;
796	>	private transient ValuesView<K,V> values;
797	>	private transient EntrySetView<K,V> entrySet;
798	>
799	>
800	>	/* ---------------- Public operations -------------- */
801	>
802	>	/**
803	>	* Creates a new, empty map with the default initial table size (16).
804	>	*/
805	>	public ConcurrentHashMap() {
806	>	}
807	>
808	>	/**
809	>	* Creates a new, empty map with an initial table size
810	>	* accommodating the specified number of elements without the need
811	>	* to dynamically resize.
812	>	*
813	>	* @param initialCapacity The implementation performs internal
814	>	* sizing to accommodate this many elements.
815	>	* @throws IllegalArgumentException if the initial capacity of
816	>	* elements is negative
817	>	*/
818	>	public ConcurrentHashMap(int initialCapacity) {
819	>	if (initialCapacity < 0)
820	>	throw new IllegalArgumentException();
821	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
822	>	MAXIMUM_CAPACITY :
823	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
824	>	this.sizeCtl = cap;
825	>	}
826	>
827	>	/**
828	>	* Creates a new map with the same mappings as the given map.
829	>	*
830	>	* @param m the map
831	>	*/
832	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
833	>	this.sizeCtl = DEFAULT_CAPACITY;
834	>	putAll(m);
835	>	}
836	>
837	>	/**
838	>	* Creates a new, empty map with an initial table size based on
839	>	* the given number of elements ({@code initialCapacity}) and
840	>	* initial table density ({@code loadFactor}).
841	>	*
842	>	* @param initialCapacity the initial capacity. The implementation
843	>	* performs internal sizing to accommodate this many elements,
844	>	* given the specified load factor.
845	>	* @param loadFactor the load factor (table density) for
846	>	* establishing the initial table size
847	>	* @throws IllegalArgumentException if the initial capacity of
848	>	* elements is negative or the load factor is nonpositive
849	>	*
850	>	* @since 1.6
851	>	*/
852	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
853	>	this(initialCapacity, loadFactor, 1);
854	>	}
855	>
856	>	/**
857	>	* Creates a new, empty map with an initial table size based on
858	>	* the given number of elements ({@code initialCapacity}), table
859	>	* density ({@code loadFactor}), and number of concurrently
860	>	* updating threads ({@code concurrencyLevel}).
861	>	*
862	>	* @param initialCapacity the initial capacity. The implementation
863	>	* performs internal sizing to accommodate this many elements,
864	>	* given the specified load factor.
865	>	* @param loadFactor the load factor (table density) for
866	>	* establishing the initial table size
867	>	* @param concurrencyLevel the estimated number of concurrently
868	>	* updating threads. The implementation may use this value as
869	>	* a sizing hint.
870	>	* @throws IllegalArgumentException if the initial capacity is
871	>	* negative or the load factor or concurrencyLevel are
872	>	* nonpositive
873	>	*/
874	>	public ConcurrentHashMap(int initialCapacity,
875	>	float loadFactor, int concurrencyLevel) {
876	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
877	>	throw new IllegalArgumentException();
878	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
879	>	initialCapacity = concurrencyLevel;   // as estimated threads
880	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
881	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
882	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
883	>	this.sizeCtl = cap;
884	>	}
885	>
886	>	// Original (since JDK1.2) Map methods
887	>
888	>	/**
889	>	* {@inheritDoc}
890	>	*/
891	>	public int size() {
892	>	long n = sumCount();
893	>	return ((n < 0L) ? 0 :
894	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
895	>	(int)n);
896	>	}
897	>
898	>	/**
899	>	* {@inheritDoc}
900	>	*/
901	>	public boolean isEmpty() {
902	>	return sumCount() <= 0L; // ignore transient negative values
903	>	}
904	>
905	>	/**
906	>	* Returns the value to which the specified key is mapped,
907	>	* or {@code null} if this map contains no mapping for the key.
908	>	*
909	>	* <p>More formally, if this map contains a mapping from a key
910	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
911	>	* then this method returns {@code v}; otherwise it returns
912	>	* {@code null}.  (There can be at most one such mapping.)
913	>	*
914	>	* @throws NullPointerException if the specified key is null
915	>	*/
916	>	public V get(Object key) {
917	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
918	>	int h = spread(key.hashCode());
919	>	if ((tab = table) != null && (n = tab.length) > 0 &&
920	>	(e = tabAt(tab, (n - 1) & h)) != null) {
921	>	if ((eh = e.hash) == h) {
922	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
923	>	return e.val;
924	>	}
925	>	else if (eh < 0)
926	>	return (p = e.find(h, key)) != null ? p.val : null;
927	>	while ((e = e.next) != null) {
928	>	if (e.hash == h &&
929	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
930	>	return e.val;
931		}
932		}
933	+	return null;
934	+	}
935
936	<	V replace(K key, int hash, V newValue) {
937	<	lock();
938	<	try {
939	<	HashEntry<K,V> e = getFirst(hash);
940	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
941	<	e = e.next;
942	<
943	<	V oldValue = null;
944	<	if (e != null) {
945	<	oldValue = e.value;
946	<	e.value = newValue;
947	<	}
948	<	return oldValue;
949	<	} finally {
950	<	unlock();
936	>	/**
937	>	* Tests if the specified object is a key in this table.
938	>	*
939	>	* @param  key possible key
940	>	* @return {@code true} if and only if the specified object
941	>	*         is a key in this table, as determined by the
942	>	*         {@code equals} method; {@code false} otherwise
943	>	* @throws NullPointerException if the specified key is null
944	>	*/
945	>	public boolean containsKey(Object key) {
946	>	return get(key) != null;
947	>	}
948	>
949	>	/**
950	>	* Returns {@code true} if this map maps one or more keys to the
951	>	* specified value. Note: This method may require a full traversal
952	>	* of the map, and is much slower than method {@code containsKey}.
953	>	*
954	>	* @param value value whose presence in this map is to be tested
955	>	* @return {@code true} if this map maps one or more keys to the
956	>	*         specified value
957	>	* @throws NullPointerException if the specified value is null
958	>	*/
959	>	public boolean containsValue(Object value) {
960	>	if (value == null)
961	>	throw new NullPointerException();
962	>	Node<K,V>[] t;
963	>	if ((t = table) != null) {
964	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
965	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
966	>	V v;
967	>	if ((v = p.val) == value || (v != null && value.equals(v)))
968	>	return true;
969		}
970		}
971	+	return false;
972	+	}
973
974	+	/**
975	+	* Maps the specified key to the specified value in this table.
976	+	* Neither the key nor the value can be null.
977	+	*
978	+	* <p>The value can be retrieved by calling the {@code get} method
979	+	* with a key that is equal to the original key.
980	+	*
981	+	* @param key key with which the specified value is to be associated
982	+	* @param value value to be associated with the specified key
983	+	* @return the previous value associated with {@code key}, or
984	+	*         {@code null} if there was no mapping for {@code key}
985	+	* @throws NullPointerException if the specified key or value is null
986	+	*/
987	+	public V put(K key, V value) {
988	+	return putVal(key, value, false);
989	+	}
990
991	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
992	<	lock();
993	<	try {
994	<	int c = count;
995	<	if (c++ > threshold) // ensure capacity
996	<	rehash();
997	<	HashEntry<K,V>[] tab = table;
998	<	int index = hash & (tab.length - 1);
999	<	HashEntry<K,V> first = tab[index];
1000	<	HashEntry<K,V> e = first;
1001	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
1002	<	e = e.next;
1003	<
1004	<	V oldValue;
1005	<	if (e != null) {
1006	<	oldValue = e.value;
1007	<	if (!onlyIfAbsent)
1008	<	e.value = value;
991	>	/** Implementation for put and putIfAbsent */
992	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
993	>	if (key == null || value == null) throw new NullPointerException();
994	>	int hash = spread(key.hashCode());
995	>	int binCount = 0;
996	>	for (Node<K,V>[] tab = table;;) {
997	>	Node<K,V> f; int n, i, fh;
998	>	if (tab == null || (n = tab.length) == 0)
999	>	tab = initTable();
1000	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
1001	>	if (casTabAt(tab, i, null, new Node<K,V>(hash, key, value)))
1002	>	break;                   // no lock when adding to empty bin
1003	>	}
1004	>	else if ((fh = f.hash) == MOVED)
1005	>	tab = helpTransfer(tab, f);
1006	>	else {
1007	>	V oldVal = null;
1008	>	synchronized (f) {
1009	>	if (tabAt(tab, i) == f) {
1010	>	if (fh >= 0) {
1011	>	binCount = 1;
1012	>	for (Node<K,V> e = f;; ++binCount) {
1013	>	K ek;
1014	>	if (e.hash == hash &&
1015	>	((ek = e.key) == key ||
1016	>	(ek != null && key.equals(ek)))) {
1017	>	oldVal = e.val;
1018	>	if (!onlyIfAbsent)
1019	>	e.val = value;
1020	>	break;
1021	>	}
1022	>	Node<K,V> pred = e;
1023	>	if ((e = e.next) == null) {
1024	>	pred.next = new Node<K,V>(hash, key, value);
1025	>	break;
1026	>	}
1027	>	}
1028	>	}
1029	>	else if (f instanceof TreeBin) {
1030	>	Node<K,V> p;
1031	>	binCount = 2;
1032	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1033	>	value)) != null) {
1034	>	oldVal = p.val;
1035	>	if (!onlyIfAbsent)
1036	>	p.val = value;
1037	>	}
1038	>	}
1039	>	else if (f instanceof ReservationNode)
1040	>	throw new IllegalStateException("Recursive update");
1041	>	}
1042		}
1043	<	else {
1044	<	oldValue = null;
1045	<	++modCount;
1046	<	tab[index] = new HashEntry<K,V>(key, hash, first, value);
1047	<	count = c; // write-volatile
1043	>	if (binCount != 0) {
1044	>	if (binCount >= TREEIFY_THRESHOLD)
1045	>	treeifyBin(tab, i);
1046	>	if (oldVal != null)
1047	>	return oldVal;
1048	>	break;
1049		}
437	–	return oldValue;
438	–	} finally {
439	–	unlock();
1050		}
1051		}
1052	+	addCount(1L, binCount);
1053	+	return null;
1054	+	}
1055
1056	<	void rehash() {
1057	<	HashEntry<K,V>[] oldTable = table;
1058	<	int oldCapacity = oldTable.length;
1059	<	if (oldCapacity >= MAXIMUM_CAPACITY)
1060	<	return;
1056	>	/**
1057	>	* Copies all of the mappings from the specified map to this one.
1058	>	* These mappings replace any mappings that this map had for any of the
1059	>	* keys currently in the specified map.
1060	>	*
1061	>	* @param m mappings to be stored in this map
1062	>	*/
1063	>	public void putAll(Map<? extends K, ? extends V> m) {
1064	>	tryPresize(m.size());
1065	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1066	>	putVal(e.getKey(), e.getValue(), false);
1067	>	}
1068
1069	<	/*
1070	<	* Reclassify nodes in each list to new Map.  Because we are
1071	<	* using power-of-two expansion, the elements from each bin
1072	<	* must either stay at same index, or move with a power of two
1073	<	* offset. We eliminate unnecessary node creation by catching
1074	<	* cases where old nodes can be reused because their next
1075	<	* fields won't change. Statistically, at the default
1076	<	* threshold, only about one-sixth of them need cloning when
1077	<	* a table doubles. The nodes they replace will be garbage
1078	<	* collectable as soon as they are no longer referenced by any
1079	<	* reader thread that may be in the midst of traversing table
1080	<	* right now.
461	<	*/
462	<
463	<	HashEntry<K,V>[] newTable = HashEntry.newArray(oldCapacity<<1);
464	<	threshold = (int)(newTable.length * loadFactor);
465	<	int sizeMask = newTable.length - 1;
466	<	for (int i = 0; i < oldCapacity ; i++) {
467	<	// We need to guarantee that any existing reads of old Map can
468	<	//  proceed. So we cannot yet null out each bin.
469	<	HashEntry<K,V> e = oldTable[i];
470	<
471	<	if (e != null) {
472	<	HashEntry<K,V> next = e.next;
473	<	int idx = e.hash & sizeMask;
474	<
475	<	//  Single node on list
476	<	if (next == null)
477	<	newTable[idx] = e;
1069	>	/**
1070	>	* Removes the key (and its corresponding value) from this map.
1071	>	* This method does nothing if the key is not in the map.
1072	>	*
1073	>	* @param  key the key that needs to be removed
1074	>	* @return the previous value associated with {@code key}, or
1075	>	*         {@code null} if there was no mapping for {@code key}
1076	>	* @throws NullPointerException if the specified key is null
1077	>	*/
1078	>	public V remove(Object key) {
1079	>	return replaceNode(key, null, null);
1080	>	}
1081
1082	<	else {
1083	<	// Reuse trailing consecutive sequence at same slot
1084	<	HashEntry<K,V> lastRun = e;
1085	<	int lastIdx = idx;
1086	<	for (HashEntry<K,V> last = next;
1087	<	last != null;
1088	<	last = last.next) {
1089	<	int k = last.hash & sizeMask;
1090	<	if (k != lastIdx) {
1091	<	lastIdx = k;
1092	<	lastRun = last;
1082	>	/**
1083	>	* Implementation for the four public remove/replace methods:
1084	>	* Replaces node value with v, conditional upon match of cv if
1085	>	* non-null.  If resulting value is null, delete.
1086	>	*/
1087	>	final V replaceNode(Object key, V value, Object cv) {
1088	>	int hash = spread(key.hashCode());
1089	>	for (Node<K,V>[] tab = table;;) {
1090	>	Node<K,V> f; int n, i, fh;
1091	>	if (tab == null || (n = tab.length) == 0 ||
1092	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1093	>	break;
1094	>	else if ((fh = f.hash) == MOVED)
1095	>	tab = helpTransfer(tab, f);
1096	>	else {
1097	>	V oldVal = null;
1098	>	boolean validated = false;
1099	>	synchronized (f) {
1100	>	if (tabAt(tab, i) == f) {
1101	>	if (fh >= 0) {
1102	>	validated = true;
1103	>	for (Node<K,V> e = f, pred = null;;) {
1104	>	K ek;
1105	>	if (e.hash == hash &&
1106	>	((ek = e.key) == key ||
1107	>	(ek != null && key.equals(ek)))) {
1108	>	V ev = e.val;
1109	>	if (cv == null || cv == ev ||
1110	>	(ev != null && cv.equals(ev))) {
1111	>	oldVal = ev;
1112	>	if (value != null)
1113	>	e.val = value;
1114	>	else if (pred != null)
1115	>	pred.next = e.next;
1116	>	else
1117	>	setTabAt(tab, i, e.next);
1118	>	}
1119	>	break;
1120	>	}
1121	>	pred = e;
1122	>	if ((e = e.next) == null)
1123	>	break;
1124		}
1125		}
1126	<	newTable[lastIdx] = lastRun;
1127	<
1128	<	// Clone all remaining nodes
1129	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1130	<	int k = p.hash & sizeMask;
1131	<	HashEntry<K,V> n = newTable[k];
1132	<	newTable[k] = new HashEntry<K,V>(p.key, p.hash,
1133	<	n, p.value);
1126	>	else if (f instanceof TreeBin) {
1127	>	validated = true;
1128	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1129	>	TreeNode<K,V> r, p;
1130	>	if ((r = t.root) != null &&
1131	>	(p = r.findTreeNode(hash, key, null)) != null) {
1132	>	V pv = p.val;
1133	>	if (cv == null || cv == pv ||
1134	>	(pv != null && cv.equals(pv))) {
1135	>	oldVal = pv;
1136	>	if (value != null)
1137	>	p.val = value;
1138	>	else if (t.removeTreeNode(p))
1139	>	setTabAt(tab, i, untreeify(t.first));
1140	>	}
1141	>	}
1142		}
1143	+	else if (f instanceof ReservationNode)
1144	+	throw new IllegalStateException("Recursive update");
1145		}
1146		}
1147	<	}
1148	<	table = newTable;
1149	<	}
1150	<
1151	<	/**
508	<	* Remove; match on key only if value null, else match both.
509	<	*/
510	<	V remove(Object key, int hash, Object value) {
511	<	lock();
512	<	try {
513	<	int c = count - 1;
514	<	HashEntry<K,V>[] tab = table;
515	<	int index = hash & (tab.length - 1);
516	<	HashEntry<K,V> first = tab[index];
517	<	HashEntry<K,V> e = first;
518	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
519	<	e = e.next;
520	<
521	<	V oldValue = null;
522	<	if (e != null) {
523	<	V v = e.value;
524	<	if (value == null || value.equals(v)) {
525	<	oldValue = v;
526	<	// All entries following removed node can stay
527	<	// in list, but all preceding ones need to be
528	<	// cloned.
529	<	++modCount;
530	<	HashEntry<K,V> newFirst = e.next;
531	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
532	<	newFirst = new HashEntry<K,V>(p.key, p.hash,
533	<	newFirst, p.value);
534	<	tab[index] = newFirst;
535	<	count = c; // write-volatile
1147	>	if (validated) {
1148	>	if (oldVal != null) {
1149	>	if (value == null)
1150	>	addCount(-1L, -1);
1151	>	return oldVal;
1152		}
1153	+	break;
1154		}
538	–	return oldValue;
539	–	} finally {
540	–	unlock();
1155		}
1156		}
1157	+	return null;
1158	+	}
1159
1160	<	void clear() {
1161	<	if (count != 0) {
1162	<	lock();
1163	<	try {
1164	<	HashEntry<K,V>[] tab = table;
1165	<	for (int i = 0; i < tab.length ; i++)
1166	<	tab[i] = null;
1167	<	++modCount;
1168	<	count = 0; // write-volatile
1169	<	} finally {
1170	<	unlock();
1160	>	/**
1161	>	* Removes all of the mappings from this map.
1162	>	*/
1163	>	public void clear() {
1164	>	long delta = 0L; // negative number of deletions
1165	>	int i = 0;
1166	>	Node<K,V>[] tab = table;
1167	>	while (tab != null && i < tab.length) {
1168	>	int fh;
1169	>	Node<K,V> f = tabAt(tab, i);
1170	>	if (f == null)
1171	>	++i;
1172	>	else if ((fh = f.hash) == MOVED) {
1173	>	tab = helpTransfer(tab, f);
1174	>	i = 0; // restart
1175	>	}
1176	>	else {
1177	>	synchronized (f) {
1178	>	if (tabAt(tab, i) == f) {
1179	>	Node<K,V> p = (fh >= 0 ? f :
1180	>	(f instanceof TreeBin) ?
1181	>	((TreeBin<K,V>)f).first : null);
1182	>	while (p != null) {
1183	>	--delta;
1184	>	p = p.next;
1185	>	}
1186	>	setTabAt(tab, i++, null);
1187	>	}
1188		}
1189		}
1190		}
1191	+	if (delta != 0L)
1192	+	addCount(delta, -1);
1193		}
1194
1195	+	/**
1196	+	* Returns a {@link Set} view of the keys contained in this map.
1197	+	* The set is backed by the map, so changes to the map are
1198	+	* reflected in the set, and vice-versa. The set supports element
1199	+	* removal, which removes the corresponding mapping from this map,
1200	+	* via the {@code Iterator.remove}, {@code Set.remove},
1201	+	* {@code removeAll}, {@code retainAll}, and {@code clear}
1202	+	* operations.  It does not support the {@code add} or
1203	+	* {@code addAll} operations.
1204	+	*
1205	+	* <p>The view's iterators and spliterators are
1206	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1207	+	*
1208	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1209	+	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1210	+	*
1211	+	* @return the set view
1212	+	*/
1213	+	public KeySetView<K,V> keySet() {
1214	+	KeySetView<K,V> ks;
1215	+	if ((ks = keySet) != null) return ks;
1216	+	return keySet = new KeySetView<K,V>(this, null);
1217	+	}
1218
1219	+	/**
1220	+	* Returns a {@link Collection} view of the values contained in this map.
1221	+	* The collection is backed by the map, so changes to the map are
1222	+	* reflected in the collection, and vice-versa.  The collection
1223	+	* supports element removal, which removes the corresponding
1224	+	* mapping from this map, via the {@code Iterator.remove},
1225	+	* {@code Collection.remove}, {@code removeAll},
1226	+	* {@code retainAll}, and {@code clear} operations.  It does not
1227	+	* support the {@code add} or {@code addAll} operations.
1228	+	*
1229	+	* <p>The view's iterators and spliterators are
1230	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1231	+	*
1232	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1233	+	* and {@link Spliterator#NONNULL}.
1234	+	*
1235	+	* @return the collection view
1236	+	*/
1237	+	public Collection<V> values() {
1238	+	ValuesView<K,V> vs;
1239	+	if ((vs = values) != null) return vs;
1240	+	return values = new ValuesView<K,V>(this);
1241	+	}
1242
1243	<	/* ---------------- Public operations -------------- */
1243	>	/**
1244	>	* Returns a {@link Set} view of the mappings contained in this map.
1245	>	* The set is backed by the map, so changes to the map are
1246	>	* reflected in the set, and vice-versa.  The set supports element
1247	>	* removal, which removes the corresponding mapping from the map,
1248	>	* via the {@code Iterator.remove}, {@code Set.remove},
1249	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1250	>	* operations.
1251	>	*
1252	>	* <p>The view's iterators and spliterators are
1253	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1254	>	*
1255	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1256	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1257	>	*
1258	>	* @return the set view
1259	>	*/
1260	>	public Set<Map.Entry<K,V>> entrySet() {
1261	>	EntrySetView<K,V> es;
1262	>	if ((es = entrySet) != null) return es;
1263	>	return entrySet = new EntrySetView<K,V>(this);
1264	>	}
1265
1266		/**
1267	<	* Creates a new, empty map with the specified initial
1268	<	* capacity, load factor and concurrency level.
1267	>	* Returns the hash code value for this {@link Map}, i.e.,
1268	>	* the sum of, for each key-value pair in the map,
1269	>	* {@code key.hashCode() ^ value.hashCode()}.
1270		*
1271	<	* @param initialCapacity the initial capacity. The implementation
569	<	* performs internal sizing to accommodate this many elements.
570	<	* @param loadFactor  the load factor threshold, used to control resizing.
571	<	* Resizing may be performed when the average number of elements per
572	<	* bin exceeds this threshold.
573	<	* @param concurrencyLevel the estimated number of concurrently
574	<	* updating threads. The implementation performs internal sizing
575	<	* to try to accommodate this many threads.
576	<	* @throws IllegalArgumentException if the initial capacity is
577	<	* negative or the load factor or concurrencyLevel are
578	<	* nonpositive.
1271	>	* @return the hash code value for this map
1272		*/
1273	<	public ConcurrentHashMap(int initialCapacity,
1274	<	float loadFactor, int concurrencyLevel) {
1275	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
1276	<	throw new IllegalArgumentException();
1273	>	public int hashCode() {
1274	>	int h = 0;
1275	>	Node<K,V>[] t;
1276	>	if ((t = table) != null) {
1277	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1278	>	for (Node<K,V> p; (p = it.advance()) != null; )
1279	>	h += p.key.hashCode() ^ p.val.hashCode();
1280	>	}
1281	>	return h;
1282	>	}
1283
1284	<	if (concurrencyLevel > MAX_SEGMENTS)
1285	<	concurrencyLevel = MAX_SEGMENTS;
1284	>	/**
1285	>	* Returns a string representation of this map.  The string
1286	>	* representation consists of a list of key-value mappings (in no
1287	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1288	>	* mappings are separated by the characters {@code ", "} (comma
1289	>	* and space).  Each key-value mapping is rendered as the key
1290	>	* followed by an equals sign ("{@code =}") followed by the
1291	>	* associated value.
1292	>	*
1293	>	* @return a string representation of this map
1294	>	*/
1295	>	public String toString() {
1296	>	Node<K,V>[] t;
1297	>	int f = (t = table) == null ? 0 : t.length;
1298	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1299	>	StringBuilder sb = new StringBuilder();
1300	>	sb.append('{');
1301	>	Node<K,V> p;
1302	>	if ((p = it.advance()) != null) {
1303	>	for (;;) {
1304	>	K k = p.key;
1305	>	V v = p.val;
1306	>	sb.append(k == this ? "(this Map)" : k);
1307	>	sb.append('=');
1308	>	sb.append(v == this ? "(this Map)" : v);
1309	>	if ((p = it.advance()) == null)
1310	>	break;
1311	>	sb.append(',').append(' ');
1312	>	}
1313	>	}
1314	>	return sb.append('}').toString();
1315	>	}
1316
1317	<	// Find power-of-two sizes best matching arguments
1317	>	/**
1318	>	* Compares the specified object with this map for equality.
1319	>	* Returns {@code true} if the given object is a map with the same
1320	>	* mappings as this map.  This operation may return misleading
1321	>	* results if either map is concurrently modified during execution
1322	>	* of this method.
1323	>	*
1324	>	* @param o object to be compared for equality with this map
1325	>	* @return {@code true} if the specified object is equal to this map
1326	>	*/
1327	>	public boolean equals(Object o) {
1328	>	if (o != this) {
1329	>	if (!(o instanceof Map))
1330	>	return false;
1331	>	Map<?,?> m = (Map<?,?>) o;
1332	>	Node<K,V>[] t;
1333	>	int f = (t = table) == null ? 0 : t.length;
1334	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1335	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1336	>	V val = p.val;
1337	>	Object v = m.get(p.key);
1338	>	if (v == null || (v != val && !v.equals(val)))
1339	>	return false;
1340	>	}
1341	>	for (Map.Entry<?,?> e : m.entrySet()) {
1342	>	Object mk, mv, v;
1343	>	if ((mk = e.getKey()) == null ||
1344	>	(mv = e.getValue()) == null ||
1345	>	(v = get(mk)) == null ||
1346	>	(mv != v && !mv.equals(v)))
1347	>	return false;
1348	>	}
1349	>	}
1350	>	return true;
1351	>	}
1352	>
1353	>	/**
1354	>	* Stripped-down version of helper class used in previous version,
1355	>	* declared for the sake of serialization compatibility.
1356	>	*/
1357	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1358	>	private static final long serialVersionUID = 2249069246763182397L;
1359	>	final float loadFactor;
1360	>	Segment(float lf) { this.loadFactor = lf; }
1361	>	}
1362	>
1363	>	/**
1364	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1365	>	* stream (i.e., serializes it).
1366	>	* @param s the stream
1367	>	* @throws java.io.IOException if an I/O error occurs
1368	>	* @serialData
1369	>	* the serialized fields, followed by the key (Object) and value
1370	>	* (Object) for each key-value mapping, followed by a null pair.
1371	>	* The key-value mappings are emitted in no particular order.
1372	>	*/
1373	>	private void writeObject(java.io.ObjectOutputStream s)
1374	>	throws java.io.IOException {
1375	>	// For serialization compatibility
1376	>	// Emulate segment calculation from previous version of this class
1377		int sshift = 0;
1378		int ssize = 1;
1379	<	while (ssize < concurrencyLevel) {
1379	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1380		++sshift;
1381		ssize <<= 1;
1382		}
1383	<	segmentShift = 32 - sshift;
1384	<	segmentMask = ssize - 1;
1385	<	this.segments = Segment.newArray(ssize);
1386	<
1387	<	if (initialCapacity > MAXIMUM_CAPACITY)
1388	<	initialCapacity = MAXIMUM_CAPACITY;
1389	<	int c = initialCapacity / ssize;
1390	<	if (c * ssize < initialCapacity)
1391	<	++c;
1392	<	int cap = 1;
1393	<	while (cap < c)
1394	<	cap <<= 1;
1383	>	int segmentShift = 32 - sshift;
1384	>	int segmentMask = ssize - 1;
1385	>	@SuppressWarnings("unchecked")
1386	>	Segment<K,V>[] segments = (Segment<K,V>[])
1387	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1388	>	for (int i = 0; i < segments.length; ++i)
1389	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1390	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1391	>	streamFields.put("segments", segments);
1392	>	streamFields.put("segmentShift", segmentShift);
1393	>	streamFields.put("segmentMask", segmentMask);
1394	>	s.writeFields();
1395	>
1396	>	Node<K,V>[] t;
1397	>	if ((t = table) != null) {
1398	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1399	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1400	>	s.writeObject(p.key);
1401	>	s.writeObject(p.val);
1402	>	}
1403	>	}
1404	>	s.writeObject(null);
1405	>	s.writeObject(null);
1406	>	}
1407
1408	<	for (int i = 0; i < this.segments.length; ++i)
1409	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
1408	>	/**
1409	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1410	>	* @param s the stream
1411	>	* @throws ClassNotFoundException if the class of a serialized object
1412	>	*         could not be found
1413	>	* @throws java.io.IOException if an I/O error occurs
1414	>	*/
1415	>	private void readObject(java.io.ObjectInputStream s)
1416	>	throws java.io.IOException, ClassNotFoundException {
1417	>	/*
1418	>	* To improve performance in typical cases, we create nodes
1419	>	* while reading, then place in table once size is known.
1420	>	* However, we must also validate uniqueness and deal with
1421	>	* overpopulated bins while doing so, which requires
1422	>	* specialized versions of putVal mechanics.
1423	>	*/
1424	>	sizeCtl = -1; // force exclusion for table construction
1425	>	s.defaultReadObject();
1426	>	long size = 0L;
1427	>	Node<K,V> p = null;
1428	>	for (;;) {
1429	>	@SuppressWarnings("unchecked")
1430	>	K k = (K) s.readObject();
1431	>	@SuppressWarnings("unchecked")
1432	>	V v = (V) s.readObject();
1433	>	if (k != null && v != null) {
1434	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1435	>	++size;
1436	>	}
1437	>	else
1438	>	break;
1439	>	}
1440	>	if (size == 0L)
1441	>	sizeCtl = 0;
1442	>	else {
1443	>	int n;
1444	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1445	>	n = MAXIMUM_CAPACITY;
1446	>	else {
1447	>	int sz = (int)size;
1448	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1449	>	}
1450	>	@SuppressWarnings("unchecked")
1451	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1452	>	int mask = n - 1;
1453	>	long added = 0L;
1454	>	while (p != null) {
1455	>	boolean insertAtFront;
1456	>	Node<K,V> next = p.next, first;
1457	>	int h = p.hash, j = h & mask;
1458	>	if ((first = tabAt(tab, j)) == null)
1459	>	insertAtFront = true;
1460	>	else {
1461	>	K k = p.key;
1462	>	if (first.hash < 0) {
1463	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1464	>	if (t.putTreeVal(h, k, p.val) == null)
1465	>	++added;
1466	>	insertAtFront = false;
1467	>	}
1468	>	else {
1469	>	int binCount = 0;
1470	>	insertAtFront = true;
1471	>	Node<K,V> q; K qk;
1472	>	for (q = first; q != null; q = q.next) {
1473	>	if (q.hash == h &&
1474	>	((qk = q.key) == k ||
1475	>	(qk != null && k.equals(qk)))) {
1476	>	insertAtFront = false;
1477	>	break;
1478	>	}
1479	>	++binCount;
1480	>	}
1481	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1482	>	insertAtFront = false;
1483	>	++added;
1484	>	p.next = first;
1485	>	TreeNode<K,V> hd = null, tl = null;
1486	>	for (q = p; q != null; q = q.next) {
1487	>	TreeNode<K,V> t = new TreeNode<K,V>
1488	>	(q.hash, q.key, q.val, null, null);
1489	>	if ((t.prev = tl) == null)
1490	>	hd = t;
1491	>	else
1492	>	tl.next = t;
1493	>	tl = t;
1494	>	}
1495	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1496	>	}
1497	>	}
1498	>	}
1499	>	if (insertAtFront) {
1500	>	++added;
1501	>	p.next = first;
1502	>	setTabAt(tab, j, p);
1503	>	}
1504	>	p = next;
1505	>	}
1506	>	table = tab;
1507	>	sizeCtl = n - (n >>> 2);
1508	>	baseCount = added;
1509	>	}
1510		}
1511
1512	+	// ConcurrentMap methods
1513	+
1514		/**
1515	<	* Creates a new, empty map with the specified initial capacity
614	<	* and load factor and with the default concurrencyLevel (16).
615	<	*
616	<	* @param initialCapacity The implementation performs internal
617	<	* sizing to accommodate this many elements.
618	<	* @param loadFactor  the load factor threshold, used to control resizing.
619	<	* Resizing may be performed when the average number of elements per
620	<	* bin exceeds this threshold.
621	<	* @throws IllegalArgumentException if the initial capacity of
622	<	* elements is negative or the load factor is nonpositive
1515	>	* {@inheritDoc}
1516		*
1517	<	* @since 1.6
1517	>	* @return the previous value associated with the specified key,
1518	>	*         or {@code null} if there was no mapping for the key
1519	>	* @throws NullPointerException if the specified key or value is null
1520		*/
1521	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
1522	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1521	>	public V putIfAbsent(K key, V value) {
1522	>	return putVal(key, value, true);
1523		}
1524
1525		/**
1526	<	* Creates a new, empty map with the specified initial capacity,
632	<	* and with default load factor (0.75) and concurrencyLevel (16).
1526	>	* {@inheritDoc}
1527		*
1528	<	* @param initialCapacity the initial capacity. The implementation
635	<	* performs internal sizing to accommodate this many elements.
636	<	* @throws IllegalArgumentException if the initial capacity of
637	<	* elements is negative.
1528	>	* @throws NullPointerException if the specified key is null
1529		*/
1530	<	public ConcurrentHashMap(int initialCapacity) {
1531	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1530	>	public boolean remove(Object key, Object value) {
1531	>	if (key == null)
1532	>	throw new NullPointerException();
1533	>	return value != null && replaceNode(key, null, value) != null;
1534		}
1535
1536		/**
1537	<	* Creates a new, empty map with a default initial capacity (16),
1538	<	* load factor (0.75) and concurrencyLevel (16).
1537	>	* {@inheritDoc}
1538	>	*
1539	>	* @throws NullPointerException if any of the arguments are null
1540		*/
1541	<	public ConcurrentHashMap() {
1542	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1541	>	public boolean replace(K key, V oldValue, V newValue) {
1542	>	if (key == null || oldValue == null || newValue == null)
1543	>	throw new NullPointerException();
1544	>	return replaceNode(key, newValue, oldValue) != null;
1545		}
1546
1547		/**
1548	<	* Creates a new map with the same mappings as the given map.
653	<	* The map is created with a capacity of 1.5 times the number
654	<	* of mappings in the given map or 16 (whichever is greater),
655	<	* and a default load factor (0.75) and concurrencyLevel (16).
1548	>	* {@inheritDoc}
1549		*
1550	<	* @param m the map
1550	>	* @return the previous value associated with the specified key,
1551	>	*         or {@code null} if there was no mapping for the key
1552	>	* @throws NullPointerException if the specified key or value is null
1553		*/
1554	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
1555	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
1556	<	DEFAULT_INITIAL_CAPACITY),
1557	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
663	<	putAll(m);
1554	>	public V replace(K key, V value) {
1555	>	if (key == null || value == null)
1556	>	throw new NullPointerException();
1557	>	return replaceNode(key, value, null);
1558		}
1559
1560	+	// Overrides of JDK8+ Map extension method defaults
1561	+
1562		/**
1563	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
1563	>	* Returns the value to which the specified key is mapped, or the
1564	>	* given default value if this map contains no mapping for the
1565	>	* key.
1566		*
1567	<	* @return <tt>true</tt> if this map contains no key-value mappings
1567	>	* @param key the key whose associated value is to be returned
1568	>	* @param defaultValue the value to return if this map contains
1569	>	* no mapping for the given key
1570	>	* @return the mapping for the key, if present; else the default value
1571	>	* @throws NullPointerException if the specified key is null
1572		*/
1573	<	public boolean isEmpty() {
1574	<	final Segment<K,V>[] segments = this.segments;
1575	<	/*
1576	<	* We keep track of per-segment modCounts to avoid ABA
1577	<	* problems in which an element in one segment was added and
1578	<	* in another removed during traversal, in which case the
1579	<	* table was never actually empty at any point. Note the
1580	<	* similar use of modCounts in the size() and containsValue()
1581	<	* methods, which are the only other methods also susceptible
1582	<	* to ABA problems.
1583	<	*/
1584	<	int[] mc = new int[segments.length];
1585	<	int mcsum = 0;
684	<	for (int i = 0; i < segments.length; ++i) {
685	<	if (segments[i].count != 0)
686	<	return false;
687	<	else
688	<	mcsum += mc[i] = segments[i].modCount;
1573	>	public V getOrDefault(Object key, V defaultValue) {
1574	>	V v;
1575	>	return (v = get(key)) == null ? defaultValue : v;
1576	>	}
1577	>
1578	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1579	>	if (action == null) throw new NullPointerException();
1580	>	Node<K,V>[] t;
1581	>	if ((t = table) != null) {
1582	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1583	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1584	>	action.accept(p.key, p.val);
1585	>	}
1586		}
1587	<	// If mcsum happens to be zero, then we know we got a snapshot
1588	<	// before any modifications at all were made.  This is
1589	<	// probably common enough to bother tracking.
1590	<	if (mcsum != 0) {
1591	<	for (int i = 0; i < segments.length; ++i) {
1592	<	if (segments[i].count != 0 ||
1593	<	mc[i] != segments[i].modCount)
1594	<	return false;
1587	>	}
1588	>
1589	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1590	>	if (function == null) throw new NullPointerException();
1591	>	Node<K,V>[] t;
1592	>	if ((t = table) != null) {
1593	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1594	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1595	>	V oldValue = p.val;
1596	>	for (K key = p.key;;) {
1597	>	V newValue = function.apply(key, oldValue);
1598	>	if (newValue == null)
1599	>	throw new NullPointerException();
1600	>	if (replaceNode(key, newValue, oldValue) != null ||
1601	>	(oldValue = get(key)) == null)
1602	>	break;
1603	>	}
1604		}
1605		}
700	–	return true;
1606		}
1607
1608		/**
1609	<	* Returns the number of key-value mappings in this map.  If the
705	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
706	<	* <tt>Integer.MAX_VALUE</tt>.
707	<	*
708	<	* @return the number of key-value mappings in this map
1609	>	* Helper method for EntrySetView.removeIf.
1610		*/
1611	<	public int size() {
1612	<	final Segment<K,V>[] segments = this.segments;
1613	<	long sum = 0;
1614	<	long check = 0;
1615	<	int[] mc = new int[segments.length];
1616	<	// Try a few times to get accurate count. On failure due to
1617	<	// continuous async changes in table, resort to locking.
1618	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1619	<	check = 0;
1620	<	sum = 0;
1621	<	int mcsum = 0;
1622	<	for (int i = 0; i < segments.length; ++i) {
722	<	sum += segments[i].count;
723	<	mcsum += mc[i] = segments[i].modCount;
724	<	}
725	<	if (mcsum != 0) {
726	<	for (int i = 0; i < segments.length; ++i) {
727	<	check += segments[i].count;
728	<	if (mc[i] != segments[i].modCount) {
729	<	check = -1; // force retry
730	<	break;
731	<	}
732	<	}
1611	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1612	>	if (function == null) throw new NullPointerException();
1613	>	Node<K,V>[] t;
1614	>	boolean removed = false;
1615	>	if ((t = table) != null) {
1616	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1617	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1618	>	K k = p.key;
1619	>	V v = p.val;
1620	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1621	>	if (function.test(e) && replaceNode(k, null, v) != null)
1622	>	removed = true;
1623		}
734	–	if (check == sum)
735	–	break;
1624		}
1625	<	if (check != sum) { // Resort to locking all segments
738	<	sum = 0;
739	<	for (int i = 0; i < segments.length; ++i)
740	<	segments[i].lock();
741	<	for (int i = 0; i < segments.length; ++i)
742	<	sum += segments[i].count;
743	<	for (int i = 0; i < segments.length; ++i)
744	<	segments[i].unlock();
745	<	}
746	<	if (sum > Integer.MAX_VALUE)
747	<	return Integer.MAX_VALUE;
748	<	else
749	<	return (int)sum;
1625	>	return removed;
1626		}
1627
1628		/**
1629	<	* Returns the value to which this map maps the specified key, or
754	<	* <tt>null</tt> if the map contains no mapping for the key.
755	<	*
756	<	* @param key key whose associated value is to be returned
757	<	* @return the value to which this map maps the specified key, or
758	<	*         <tt>null</tt> if the map contains no mapping for the key
759	<	* @throws NullPointerException if the specified key is null
1629	>	* Helper method for ValuesView.removeIf.
1630		*/
1631	<	public V get(Object key) {
1632	<	int hash = hash(key); // throws NullPointerException if key null
1633	<	return segmentFor(hash).get(key, hash);
1631	>	boolean removeValueIf(Predicate<? super V> function) {
1632	>	if (function == null) throw new NullPointerException();
1633	>	Node<K,V>[] t;
1634	>	boolean removed = false;
1635	>	if ((t = table) != null) {
1636	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1637	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1638	>	K k = p.key;
1639	>	V v = p.val;
1640	>	if (function.test(v) && replaceNode(k, null, v) != null)
1641	>	removed = true;
1642	>	}
1643	>	}
1644	>	return removed;
1645		}
1646
1647		/**
1648	<	* Tests if the specified object is a key in this table.
1648	>	* If the specified key is not already associated with a value,
1649	>	* attempts to compute its value using the given mapping function
1650	>	* and enters it into this map unless {@code null}.  The entire
1651	>	* method invocation is performed atomically, so the function is
1652	>	* applied at most once per key.  Some attempted update operations
1653	>	* on this map by other threads may be blocked while computation
1654	>	* is in progress, so the computation should be short and simple,
1655	>	* and must not attempt to update any other mappings of this map.
1656		*
1657	<	* @param  key   possible key
1658	<	* @return <tt>true</tt> if and only if the specified object
1659	<	*         is a key in this table, as determined by the
1660	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
1661	<	* @throws NullPointerException if the specified key is null
1657	>	* @param key key with which the specified value is to be associated
1658	>	* @param mappingFunction the function to compute a value
1659	>	* @return the current (existing or computed) value associated with
1660	>	*         the specified key, or null if the computed value is null
1661	>	* @throws NullPointerException if the specified key or mappingFunction
1662	>	*         is null
1663	>	* @throws IllegalStateException if the computation detectably
1664	>	*         attempts a recursive update to this map that would
1665	>	*         otherwise never complete
1666	>	* @throws RuntimeException or Error if the mappingFunction does so,
1667	>	*         in which case the mapping is left unestablished
1668		*/
1669	<	public boolean containsKey(Object key) {
1670	<	int hash = hash(key); // throws NullPointerException if key null
1671	<	return segmentFor(hash).containsKey(key, hash);
1669	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1670	>	if (key == null || mappingFunction == null)
1671	>	throw new NullPointerException();
1672	>	int h = spread(key.hashCode());
1673	>	V val = null;
1674	>	int binCount = 0;
1675	>	for (Node<K,V>[] tab = table;;) {
1676	>	Node<K,V> f; int n, i, fh;
1677	>	if (tab == null || (n = tab.length) == 0)
1678	>	tab = initTable();
1679	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1680	>	Node<K,V> r = new ReservationNode<K,V>();
1681	>	synchronized (r) {
1682	>	if (casTabAt(tab, i, null, r)) {
1683	>	binCount = 1;
1684	>	Node<K,V> node = null;
1685	>	try {
1686	>	if ((val = mappingFunction.apply(key)) != null)
1687	>	node = new Node<K,V>(h, key, val);
1688	>	} finally {
1689	>	setTabAt(tab, i, node);
1690	>	}
1691	>	}
1692	>	}
1693	>	if (binCount != 0)
1694	>	break;
1695	>	}
1696	>	else if ((fh = f.hash) == MOVED)
1697	>	tab = helpTransfer(tab, f);
1698	>	else {
1699	>	boolean added = false;
1700	>	synchronized (f) {
1701	>	if (tabAt(tab, i) == f) {
1702	>	if (fh >= 0) {
1703	>	binCount = 1;
1704	>	for (Node<K,V> e = f;; ++binCount) {
1705	>	K ek;
1706	>	if (e.hash == h &&
1707	>	((ek = e.key) == key ||
1708	>	(ek != null && key.equals(ek)))) {
1709	>	val = e.val;
1710	>	break;
1711	>	}
1712	>	Node<K,V> pred = e;
1713	>	if ((e = e.next) == null) {
1714	>	if ((val = mappingFunction.apply(key)) != null) {
1715	>	if (pred.next != null)
1716	>	throw new IllegalStateException("Recursive update");
1717	>	added = true;
1718	>	pred.next = new Node<K,V>(h, key, val);
1719	>	}
1720	>	break;
1721	>	}
1722	>	}
1723	>	}
1724	>	else if (f instanceof TreeBin) {
1725	>	binCount = 2;
1726	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1727	>	TreeNode<K,V> r, p;
1728	>	if ((r = t.root) != null &&
1729	>	(p = r.findTreeNode(h, key, null)) != null)
1730	>	val = p.val;
1731	>	else if ((val = mappingFunction.apply(key)) != null) {
1732	>	added = true;
1733	>	t.putTreeVal(h, key, val);
1734	>	}
1735	>	}
1736	>	else if (f instanceof ReservationNode)
1737	>	throw new IllegalStateException("Recursive update");
1738	>	}
1739	>	}
1740	>	if (binCount != 0) {
1741	>	if (binCount >= TREEIFY_THRESHOLD)
1742	>	treeifyBin(tab, i);
1743	>	if (!added)
1744	>	return val;
1745	>	break;
1746	>	}
1747	>	}
1748	>	}
1749	>	if (val != null)
1750	>	addCount(1L, binCount);
1751	>	return val;
1752		}
1753
1754		/**
1755	<	* Returns <tt>true</tt> if this map maps one or more keys to the
1756	<	* specified value. Note: This method requires a full internal
1757	<	* traversal of the hash table, and so is much slower than
1758	<	* method <tt>containsKey</tt>.
1755	>	* If the value for the specified key is present, attempts to
1756	>	* compute a new mapping given the key and its current mapped
1757	>	* value.  The entire method invocation is performed atomically.
1758	>	* Some attempted update operations on this map by other threads
1759	>	* may be blocked while computation is in progress, so the
1760	>	* computation should be short and simple, and must not attempt to
1761	>	* update any other mappings of this map.
1762		*
1763	<	* @param value value whose presence in this map is to be tested
1764	<	* @return <tt>true</tt> if this map maps one or more keys to the
1765	<	*         specified value
1766	<	* @throws NullPointerException if the specified value is null
1763	>	* @param key key with which a value may be associated
1764	>	* @param remappingFunction the function to compute a value
1765	>	* @return the new value associated with the specified key, or null if none
1766	>	* @throws NullPointerException if the specified key or remappingFunction
1767	>	*         is null
1768	>	* @throws IllegalStateException if the computation detectably
1769	>	*         attempts a recursive update to this map that would
1770	>	*         otherwise never complete
1771	>	* @throws RuntimeException or Error if the remappingFunction does so,
1772	>	*         in which case the mapping is unchanged
1773		*/
1774	<	public boolean containsValue(Object value) {
1775	<	if (value == null)
1774	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1775	>	if (key == null || remappingFunction == null)
1776		throw new NullPointerException();
1777	+	int h = spread(key.hashCode());
1778	+	V val = null;
1779	+	int delta = 0;
1780	+	int binCount = 0;
1781	+	for (Node<K,V>[] tab = table;;) {
1782	+	Node<K,V> f; int n, i, fh;
1783	+	if (tab == null || (n = tab.length) == 0)
1784	+	tab = initTable();
1785	+	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1786	+	break;
1787	+	else if ((fh = f.hash) == MOVED)
1788	+	tab = helpTransfer(tab, f);
1789	+	else {
1790	+	synchronized (f) {
1791	+	if (tabAt(tab, i) == f) {
1792	+	if (fh >= 0) {
1793	+	binCount = 1;
1794	+	for (Node<K,V> e = f, pred = null;; ++binCount) {
1795	+	K ek;
1796	+	if (e.hash == h &&
1797	+	((ek = e.key) == key ||
1798	+	(ek != null && key.equals(ek)))) {
1799	+	val = remappingFunction.apply(key, e.val);
1800	+	if (val != null)
1801	+	e.val = val;
1802	+	else {
1803	+	delta = -1;
1804	+	Node<K,V> en = e.next;
1805	+	if (pred != null)
1806	+	pred.next = en;
1807	+	else
1808	+	setTabAt(tab, i, en);
1809	+	}
1810	+	break;
1811	+	}
1812	+	pred = e;
1813	+	if ((e = e.next) == null)
1814	+	break;
1815	+	}
1816	+	}
1817	+	else if (f instanceof TreeBin) {
1818	+	binCount = 2;
1819	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
1820	+	TreeNode<K,V> r, p;
1821	+	if ((r = t.root) != null &&
1822	+	(p = r.findTreeNode(h, key, null)) != null) {
1823	+	val = remappingFunction.apply(key, p.val);
1824	+	if (val != null)
1825	+	p.val = val;
1826	+	else {
1827	+	delta = -1;
1828	+	if (t.removeTreeNode(p))
1829	+	setTabAt(tab, i, untreeify(t.first));
1830	+	}
1831	+	}
1832	+	}
1833	+	else if (f instanceof ReservationNode)
1834	+	throw new IllegalStateException("Recursive update");
1835	+	}
1836	+	}
1837	+	if (binCount != 0)
1838	+	break;
1839	+	}
1840	+	}
1841	+	if (delta != 0)
1842	+	addCount((long)delta, binCount);
1843	+	return val;
1844	+	}
1845
1846	<	// See explanation of modCount use above
1847	<
1848	<	final Segment<K,V>[] segments = this.segments;
1849	<	int[] mc = new int[segments.length];
1850	<
1851	<	// Try a few times without locking
1852	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1853	<	int sum = 0;
1854	<	int mcsum = 0;
1855	<	for (int i = 0; i < segments.length; ++i) {
1856	<	int c = segments[i].count;
1857	<	mcsum += mc[i] = segments[i].modCount;
1858	<	if (segments[i].containsValue(value))
1859	<	return true;
1846	>	/**
1847	>	* Attempts to compute a mapping for the specified key and its
1848	>	* current mapped value (or {@code null} if there is no current
1849	>	* mapping). The entire method invocation is performed atomically.
1850	>	* Some attempted update operations on this map by other threads
1851	>	* may be blocked while computation is in progress, so the
1852	>	* computation should be short and simple, and must not attempt to
1853	>	* update any other mappings of this Map.
1854	>	*
1855	>	* @param key key with which the specified value is to be associated
1856	>	* @param remappingFunction the function to compute a value
1857	>	* @return the new value associated with the specified key, or null if none
1858	>	* @throws NullPointerException if the specified key or remappingFunction
1859	>	*         is null
1860	>	* @throws IllegalStateException if the computation detectably
1861	>	*         attempts a recursive update to this map that would
1862	>	*         otherwise never complete
1863	>	* @throws RuntimeException or Error if the remappingFunction does so,
1864	>	*         in which case the mapping is unchanged
1865	>	*/
1866	>	public V compute(K key,
1867	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1868	>	if (key == null || remappingFunction == null)
1869	>	throw new NullPointerException();
1870	>	int h = spread(key.hashCode());
1871	>	V val = null;
1872	>	int delta = 0;
1873	>	int binCount = 0;
1874	>	for (Node<K,V>[] tab = table;;) {
1875	>	Node<K,V> f; int n, i, fh;
1876	>	if (tab == null || (n = tab.length) == 0)
1877	>	tab = initTable();
1878	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1879	>	Node<K,V> r = new ReservationNode<K,V>();
1880	>	synchronized (r) {
1881	>	if (casTabAt(tab, i, null, r)) {
1882	>	binCount = 1;
1883	>	Node<K,V> node = null;
1884	>	try {
1885	>	if ((val = remappingFunction.apply(key, null)) != null) {
1886	>	delta = 1;
1887	>	node = new Node<K,V>(h, key, val);
1888	>	}
1889	>	} finally {
1890	>	setTabAt(tab, i, node);
1891	>	}
1892	>	}
1893	>	}
1894	>	if (binCount != 0)
1895	>	break;
1896		}
1897	<	boolean cleanSweep = true;
1898	<	if (mcsum != 0) {
1899	<	for (int i = 0; i < segments.length; ++i) {
1900	<	int c = segments[i].count;
1901	<	if (mc[i] != segments[i].modCount) {
1902	<	cleanSweep = false;
1903	<	break;
1897	>	else if ((fh = f.hash) == MOVED)
1898	>	tab = helpTransfer(tab, f);
1899	>	else {
1900	>	synchronized (f) {
1901	>	if (tabAt(tab, i) == f) {
1902	>	if (fh >= 0) {
1903	>	binCount = 1;
1904	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1905	>	K ek;
1906	>	if (e.hash == h &&
1907	>	((ek = e.key) == key ||
1908	>	(ek != null && key.equals(ek)))) {
1909	>	val = remappingFunction.apply(key, e.val);
1910	>	if (val != null)
1911	>	e.val = val;
1912	>	else {
1913	>	delta = -1;
1914	>	Node<K,V> en = e.next;
1915	>	if (pred != null)
1916	>	pred.next = en;
1917	>	else
1918	>	setTabAt(tab, i, en);
1919	>	}
1920	>	break;
1921	>	}
1922	>	pred = e;
1923	>	if ((e = e.next) == null) {
1924	>	val = remappingFunction.apply(key, null);
1925	>	if (val != null) {
1926	>	if (pred.next != null)
1927	>	throw new IllegalStateException("Recursive update");
1928	>	delta = 1;
1929	>	pred.next = new Node<K,V>(h, key, val);
1930	>	}
1931	>	break;
1932	>	}
1933	>	}
1934	>	}
1935	>	else if (f instanceof TreeBin) {
1936	>	binCount = 1;
1937	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1938	>	TreeNode<K,V> r, p;
1939	>	if ((r = t.root) != null)
1940	>	p = r.findTreeNode(h, key, null);
1941	>	else
1942	>	p = null;
1943	>	V pv = (p == null) ? null : p.val;
1944	>	val = remappingFunction.apply(key, pv);
1945	>	if (val != null) {
1946	>	if (p != null)
1947	>	p.val = val;
1948	>	else {
1949	>	delta = 1;
1950	>	t.putTreeVal(h, key, val);
1951	>	}
1952	>	}
1953	>	else if (p != null) {
1954	>	delta = -1;
1955	>	if (t.removeTreeNode(p))
1956	>	setTabAt(tab, i, untreeify(t.first));
1957	>	}
1958	>	}
1959	>	else if (f instanceof ReservationNode)
1960	>	throw new IllegalStateException("Recursive update");
1961		}
1962		}
1963	+	if (binCount != 0) {
1964	+	if (binCount >= TREEIFY_THRESHOLD)
1965	+	treeifyBin(tab, i);
1966	+	break;
1967	+	}
1968		}
820	–	if (cleanSweep)
821	–	return false;
1969		}
1970	<	// Resort to locking all segments
1971	<	for (int i = 0; i < segments.length; ++i)
1972	<	segments[i].lock();
1973	<	boolean found = false;
1974	<	try {
1975	<	for (int i = 0; i < segments.length; ++i) {
1976	<	if (segments[i].containsValue(value)) {
1977	<	found = true;
1970	>	if (delta != 0)
1971	>	addCount((long)delta, binCount);
1972	>	return val;
1973	>	}
1974	>
1975	>	/**
1976	>	* If the specified key is not already associated with a
1977	>	* (non-null) value, associates it with the given value.
1978	>	* Otherwise, replaces the value with the results of the given
1979	>	* remapping function, or removes if {@code null}. The entire
1980	>	* method invocation is performed atomically.  Some attempted
1981	>	* update operations on this map by other threads may be blocked
1982	>	* while computation is in progress, so the computation should be
1983	>	* short and simple, and must not attempt to update any other
1984	>	* mappings of this Map.
1985	>	*
1986	>	* @param key key with which the specified value is to be associated
1987	>	* @param value the value to use if absent
1988	>	* @param remappingFunction the function to recompute a value if present
1989	>	* @return the new value associated with the specified key, or null if none
1990	>	* @throws NullPointerException if the specified key or the
1991	>	*         remappingFunction is null
1992	>	* @throws RuntimeException or Error if the remappingFunction does so,
1993	>	*         in which case the mapping is unchanged
1994	>	*/
1995	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1996	>	if (key == null || value == null || remappingFunction == null)
1997	>	throw new NullPointerException();
1998	>	int h = spread(key.hashCode());
1999	>	V val = null;
2000	>	int delta = 0;
2001	>	int binCount = 0;
2002	>	for (Node<K,V>[] tab = table;;) {
2003	>	Node<K,V> f; int n, i, fh;
2004	>	if (tab == null || (n = tab.length) == 0)
2005	>	tab = initTable();
2006	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
2007	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value))) {
2008	>	delta = 1;
2009	>	val = value;
2010	>	break;
2011	>	}
2012	>	}
2013	>	else if ((fh = f.hash) == MOVED)
2014	>	tab = helpTransfer(tab, f);
2015	>	else {
2016	>	synchronized (f) {
2017	>	if (tabAt(tab, i) == f) {
2018	>	if (fh >= 0) {
2019	>	binCount = 1;
2020	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2021	>	K ek;
2022	>	if (e.hash == h &&
2023	>	((ek = e.key) == key ||
2024	>	(ek != null && key.equals(ek)))) {
2025	>	val = remappingFunction.apply(e.val, value);
2026	>	if (val != null)
2027	>	e.val = val;
2028	>	else {
2029	>	delta = -1;
2030	>	Node<K,V> en = e.next;
2031	>	if (pred != null)
2032	>	pred.next = en;
2033	>	else
2034	>	setTabAt(tab, i, en);
2035	>	}
2036	>	break;
2037	>	}
2038	>	pred = e;
2039	>	if ((e = e.next) == null) {
2040	>	delta = 1;
2041	>	val = value;
2042	>	pred.next = new Node<K,V>(h, key, val);
2043	>	break;
2044	>	}
2045	>	}
2046	>	}
2047	>	else if (f instanceof TreeBin) {
2048	>	binCount = 2;
2049	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2050	>	TreeNode<K,V> r = t.root;
2051	>	TreeNode<K,V> p = (r == null) ? null :
2052	>	r.findTreeNode(h, key, null);
2053	>	val = (p == null) ? value :
2054	>	remappingFunction.apply(p.val, value);
2055	>	if (val != null) {
2056	>	if (p != null)
2057	>	p.val = val;
2058	>	else {
2059	>	delta = 1;
2060	>	t.putTreeVal(h, key, val);
2061	>	}
2062	>	}
2063	>	else if (p != null) {
2064	>	delta = -1;
2065	>	if (t.removeTreeNode(p))
2066	>	setTabAt(tab, i, untreeify(t.first));
2067	>	}
2068	>	}
2069	>	else if (f instanceof ReservationNode)
2070	>	throw new IllegalStateException("Recursive update");
2071	>	}
2072	>	}
2073	>	if (binCount != 0) {
2074	>	if (binCount >= TREEIFY_THRESHOLD)
2075	>	treeifyBin(tab, i);
2076		break;
2077		}
2078		}
834	–	} finally {
835	–	for (int i = 0; i < segments.length; ++i)
836	–	segments[i].unlock();
2079		}
2080	<	return found;
2080	>	if (delta != 0)
2081	>	addCount((long)delta, binCount);
2082	>	return val;
2083		}
2084
2085	+	// Hashtable legacy methods
2086	+
2087		/**
2088	<	* Legacy method testing if some key maps into the specified value
2089	<	* in this table.  This method is identical in functionality to
2090	<	* {@link #containsValue}, and exists solely to ensure
2088	>	* Tests if some key maps into the specified value in this table.
2089	>	*
2090	>	* <p>Note that this method is identical in functionality to
2091	>	* {@link #containsValue(Object)}, and exists solely to ensure
2092		* full compatibility with class {@link java.util.Hashtable},
2093		* which supported this method prior to introduction of the
2094	<	* Java Collections framework.
2095	<
2094	>	* Java Collections Framework.
2095	>	*
2096		* @param  value a value to search for
2097	<	* @return <tt>true</tt> if and only if some key maps to the
2098	<	*         <tt>value</tt> argument in this table as
2099	<	*         determined by the <tt>equals</tt> method;
2100	<	*         <tt>false</tt> otherwise
2097	>	* @return {@code true} if and only if some key maps to the
2098	>	*         {@code value} argument in this table as
2099	>	*         determined by the {@code equals} method;
2100	>	*         {@code false} otherwise
2101		* @throws NullPointerException if the specified value is null
2102		*/
2103		public boolean contains(Object value) {
#	Line 858 | Line 2105 | public class ConcurrentHashMap<K, V> ext
2105		}
2106
2107		/**
2108	<	* Maps the specified key to the specified value in this table.
862	<	* Neither the key nor the value can be null.
863	<	*
864	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
865	<	* with a key that is equal to the original key.
2108	>	* Returns an enumeration of the keys in this table.
2109		*
2110	<	* @param key key with which the specified value is to be associated
2111	<	* @param value value to be associated with the specified key
869	<	* @return the previous value associated with <tt>key</tt>, or
870	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
871	<	* @throws NullPointerException if the specified key or value is null
2110	>	* @return an enumeration of the keys in this table
2111	>	* @see #keySet()
2112		*/
2113	<	public V put(K key, V value) {
2114	<	if (value == null)
2115	<	throw new NullPointerException();
2116	<	int hash = hash(key);
877	<	return segmentFor(hash).put(key, hash, value, false);
2113	>	public Enumeration<K> keys() {
2114	>	Node<K,V>[] t;
2115	>	int f = (t = table) == null ? 0 : t.length;
2116	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2117		}
2118
2119		/**
2120	<	* {@inheritDoc}
2120	>	* Returns an enumeration of the values in this table.
2121		*
2122	<	* @return the previous value associated with the specified key,
2123	<	*         or <tt>null</tt> if there was no mapping for the key
885	<	* @throws NullPointerException if the specified key or value is null
2122	>	* @return an enumeration of the values in this table
2123	>	* @see #values()
2124		*/
2125	<	public V putIfAbsent(K key, V value) {
2126	<	if (value == null)
2127	<	throw new NullPointerException();
2128	<	int hash = hash(key);
891	<	return segmentFor(hash).put(key, hash, value, true);
2125	>	public Enumeration<V> elements() {
2126	>	Node<K,V>[] t;
2127	>	int f = (t = table) == null ? 0 : t.length;
2128	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2129		}
2130
2131	+	// ConcurrentHashMap-only methods
2132	+
2133		/**
2134	<	* Copies all of the mappings from the specified map to this one.
2135	<	* These mappings replace any mappings that this map had for any of the
2136	<	* keys currently in the specified map.
2134	>	* Returns the number of mappings. This method should be used
2135	>	* instead of {@link #size} because a ConcurrentHashMap may
2136	>	* contain more mappings than can be represented as an int. The
2137	>	* value returned is an estimate; the actual count may differ if
2138	>	* there are concurrent insertions or removals.
2139		*
2140	<	* @param m mappings to be stored in this map
2140	>	* @return the number of mappings
2141	>	* @since 1.8
2142		*/
2143	<	public void putAll(Map<? extends K, ? extends V> m) {
2144	<	for (Iterator<? extends Map.Entry<? extends K, ? extends V>> it = (Iterator<? extends Map.Entry<? extends K, ? extends V>>) m.entrySet().iterator(); it.hasNext(); ) {
2145	<	Entry<? extends K, ? extends V> e = it.next();
904	<	put(e.getKey(), e.getValue());
905	<	}
2143	>	public long mappingCount() {
2144	>	long n = sumCount();
2145	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2146		}
2147
2148		/**
2149	<	* Removes the key (and its corresponding value) from this map.
2150	<	* This method does nothing if the key is not in the map.
2149	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2150	>	* from the given type to {@code Boolean.TRUE}.
2151		*
2152	<	* @param  key the key that needs to be removed
2153	<	* @return the previous value associated with <tt>key</tt>, or
2154	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>.
2155	<	* @throws NullPointerException if the specified key is null
2156	<	*/
2157	<	public V remove(Object key) {
2158	<	int hash = hash(key);
919	<	return segmentFor(hash).remove(key, hash, null);
2152	>	* @param <K> the element type of the returned set
2153	>	* @return the new set
2154	>	* @since 1.8
2155	>	*/
2156	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2157	>	return new KeySetView<K,Boolean>
2158	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2159		}
2160
2161		/**
2162	<	* {@inheritDoc}
2162	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2163	>	* from the given type to {@code Boolean.TRUE}.
2164		*
2165	<	* @throws NullPointerException if the specified key is null
2165	>	* @param initialCapacity The implementation performs internal
2166	>	* sizing to accommodate this many elements.
2167	>	* @param <K> the element type of the returned set
2168	>	* @return the new set
2169	>	* @throws IllegalArgumentException if the initial capacity of
2170	>	* elements is negative
2171	>	* @since 1.8
2172		*/
2173	<	public boolean remove(Object key, Object value) {
2174	<	if (value == null)
2175	<	return false;
930	<	int hash = hash(key);
931	<	return segmentFor(hash).remove(key, hash, value) != null;
2173	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2174	>	return new KeySetView<K,Boolean>
2175	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2176		}
2177
2178		/**
2179	<	* {@inheritDoc}
2179	>	* Returns a {@link Set} view of the keys in this map, using the
2180	>	* given common mapped value for any additions (i.e., {@link
2181	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2182	>	* This is of course only appropriate if it is acceptable to use
2183	>	* the same value for all additions from this view.
2184		*
2185	<	* @throws NullPointerException if any of the arguments are null
2185	>	* @param mappedValue the mapped value to use for any additions
2186	>	* @return the set view
2187	>	* @throws NullPointerException if the mappedValue is null
2188		*/
2189	<	public boolean replace(K key, V oldValue, V newValue) {
2190	<	if (oldValue == null || newValue == null)
2189	>	public KeySetView<K,V> keySet(V mappedValue) {
2190	>	if (mappedValue == null)
2191		throw new NullPointerException();
2192	<	int hash = hash(key);
943	<	return segmentFor(hash).replace(key, hash, oldValue, newValue);
2192	>	return new KeySetView<K,V>(this, mappedValue);
2193		}
2194
2195	+	/* ---------------- Special Nodes -------------- */
2196	+
2197		/**
2198	<	* {@inheritDoc}
948	<	*
949	<	* @return the previous value associated with the specified key,
950	<	*         or <tt>null</tt> if there was no mapping for the key
951	<	* @throws NullPointerException if the specified key or value is null
2198	>	* A node inserted at head of bins during transfer operations.
2199		*/
2200	<	public V replace(K key, V value) {
2201	<	if (value == null)
2202	<	throw new NullPointerException();
2203	<	int hash = hash(key);
2204	<	return segmentFor(hash).replace(key, hash, value);
2200	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2201	>	final Node<K,V>[] nextTable;
2202	>	ForwardingNode(Node<K,V>[] tab) {
2203	>	super(MOVED, null, null);
2204	>	this.nextTable = tab;
2205	>	}
2206	>
2207	>	Node<K,V> find(int h, Object k) {
2208	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2209	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2210	>	Node<K,V> e; int n;
2211	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2212	>	(e = tabAt(tab, (n - 1) & h)) == null)
2213	>	return null;
2214	>	for (;;) {
2215	>	int eh; K ek;
2216	>	if ((eh = e.hash) == h &&
2217	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2218	>	return e;
2219	>	if (eh < 0) {
2220	>	if (e instanceof ForwardingNode) {
2221	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2222	>	continue outer;
2223	>	}
2224	>	else
2225	>	return e.find(h, k);
2226	>	}
2227	>	if ((e = e.next) == null)
2228	>	return null;
2229	>	}
2230	>	}
2231	>	}
2232		}
2233
2234		/**
2235	<	* Removes all of the mappings from this map.
2235	>	* A place-holder node used in computeIfAbsent and compute.
2236		*/
2237	<	public void clear() {
2238	<	for (int i = 0; i < segments.length; ++i)
2239	<	segments[i].clear();
2237	>	static final class ReservationNode<K,V> extends Node<K,V> {
2238	>	ReservationNode() {
2239	>	super(RESERVED, null, null);
2240	>	}
2241	>
2242	>	Node<K,V> find(int h, Object k) {
2243	>	return null;
2244	>	}
2245		}
2246
2247	+	/* ---------------- Table Initialization and Resizing -------------- */
2248	+
2249		/**
2250	<	* Returns a {@link Set} view of the keys contained in this map.
2251	<	* The set is backed by the map, so changes to the map are
2252	<	* reflected in the set, and vice-versa.  The set supports element
2253	<	* removal, which removes the corresponding mapping from this map,
2254	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
974	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
975	<	* operations.  It does not support the <tt>add</tt> or
976	<	* <tt>addAll</tt> operations.
977	<	*
978	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
979	<	* that will never throw {@link ConcurrentModificationException},
980	<	* and guarantees to traverse elements as they existed upon
981	<	* construction of the iterator, and may (but is not guaranteed to)
982	<	* reflect any modifications subsequent to construction.
983	<	*/
984	<	public Set<K> keySet() {
985	<	Set<K> ks = keySet;
986	<	return (ks != null) ? ks : (keySet = new KeySet());
2250	>	* Returns the stamp bits for resizing a table of size n.
2251	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2252	>	*/
2253	>	static final int resizeStamp(int n) {
2254	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2255		}
2256
2257		/**
2258	<	* Returns a {@link Collection} view of the values contained in this map.
991	<	* The collection is backed by the map, so changes to the map are
992	<	* reflected in the collection, and vice-versa.  The collection
993	<	* supports element removal, which removes the corresponding
994	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
995	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
996	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
997	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
998	<	*
999	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1000	<	* that will never throw {@link ConcurrentModificationException},
1001	<	* and guarantees to traverse elements as they existed upon
1002	<	* construction of the iterator, and may (but is not guaranteed to)
1003	<	* reflect any modifications subsequent to construction.
2258	>	* Initializes table, using the size recorded in sizeCtl.
2259		*/
2260	<	public Collection<V> values() {
2261	<	Collection<V> vs = values;
2262	<	return (vs != null) ? vs : (values = new Values());
2260	>	private final Node<K,V>[] initTable() {
2261	>	Node<K,V>[] tab; int sc;
2262	>	while ((tab = table) == null || tab.length == 0) {
2263	>	if ((sc = sizeCtl) < 0)
2264	>	Thread.yield(); // lost initialization race; just spin
2265	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2266	>	try {
2267	>	if ((tab = table) == null || tab.length == 0) {
2268	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2269	>	@SuppressWarnings("unchecked")
2270	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2271	>	table = tab = nt;
2272	>	sc = n - (n >>> 2);
2273	>	}
2274	>	} finally {
2275	>	sizeCtl = sc;
2276	>	}
2277	>	break;
2278	>	}
2279	>	}
2280	>	return tab;
2281		}
2282
2283		/**
2284	<	* Returns a {@link Set} view of the mappings contained in this map.
2285	<	* The set is backed by the map, so changes to the map are
2286	<	* reflected in the set, and vice-versa.  The set supports element
2287	<	* removal, which removes the corresponding mapping from the map,
2288	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2289	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2290	<	* operations.  It does not support the <tt>add</tt> or
2291	<	* <tt>addAll</tt> operations.
1019	<	*
1020	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1021	<	* that will never throw {@link ConcurrentModificationException},
1022	<	* and guarantees to traverse elements as they existed upon
1023	<	* construction of the iterator, and may (but is not guaranteed to)
1024	<	* reflect any modifications subsequent to construction.
2284	>	* Adds to count, and if table is too small and not already
2285	>	* resizing, initiates transfer. If already resizing, helps
2286	>	* perform transfer if work is available.  Rechecks occupancy
2287	>	* after a transfer to see if another resize is already needed
2288	>	* because resizings are lagging additions.
2289	>	*
2290	>	* @param x the count to add
2291	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2292		*/
2293	<	public Set<Map.Entry<K,V>> entrySet() {
2294	<	Set<Map.Entry<K,V>> es = entrySet;
2295	<	return (es != null) ? es : (entrySet = new EntrySet());
2293	>	private final void addCount(long x, int check) {
2294	>	CounterCell[] as; long b, s;
2295	>	if ((as = counterCells) != null ||
2296	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2297	>	CounterCell a; long v; int m;
2298	>	boolean uncontended = true;
2299	>	if (as == null || (m = as.length - 1) < 0 ||
2300	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2301	>	!(uncontended =
2302	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2303	>	fullAddCount(x, uncontended);
2304	>	return;
2305	>	}
2306	>	if (check <= 1)
2307	>	return;
2308	>	s = sumCount();
2309	>	}
2310	>	if (check >= 0) {
2311	>	Node<K,V>[] tab, nt; int n, sc;
2312	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2313	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2314	>	int rs = resizeStamp(n);
2315	>	if (sc < 0) {
2316	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2317	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2318	>	transferIndex <= 0)
2319	>	break;
2320	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2321	>	transfer(tab, nt);
2322	>	}
2323	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2324	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2325	>	transfer(tab, null);
2326	>	s = sumCount();
2327	>	}
2328	>	}
2329		}
2330
2331		/**
2332	<	* Returns an enumeration of the keys in this table.
1033	<	*
1034	<	* @return an enumeration of the keys in this table
1035	<	* @see #keySet
2332	>	* Helps transfer if a resize is in progress.
2333		*/
2334	<	public Enumeration<K> keys() {
2335	<	return new KeyIterator();
2334	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2335	>	Node<K,V>[] nextTab; int sc;
2336	>	if (tab != null && (f instanceof ForwardingNode) &&
2337	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2338	>	int rs = resizeStamp(tab.length);
2339	>	while (nextTab == nextTable && table == tab &&
2340	>	(sc = sizeCtl) < 0) {
2341	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2342	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2343	>	break;
2344	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2345	>	transfer(tab, nextTab);
2346	>	break;
2347	>	}
2348	>	}
2349	>	return nextTab;
2350	>	}
2351	>	return table;
2352		}
2353
2354		/**
2355	<	* Returns an enumeration of the values in this table.
2355	>	* Tries to presize table to accommodate the given number of elements.
2356		*
2357	<	* @return an enumeration of the values in this table
1045	<	* @see #values
2357	>	* @param size number of elements (doesn't need to be perfectly accurate)
2358		*/
2359	<	public Enumeration<V> elements() {
2360	<	return new ValueIterator();
2359	>	private final void tryPresize(int size) {
2360	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2361	>	tableSizeFor(size + (size >>> 1) + 1);
2362	>	int sc;
2363	>	while ((sc = sizeCtl) >= 0) {
2364	>	Node<K,V>[] tab = table; int n;
2365	>	if (tab == null || (n = tab.length) == 0) {
2366	>	n = (sc > c) ? sc : c;
2367	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2368	>	try {
2369	>	if (table == tab) {
2370	>	@SuppressWarnings("unchecked")
2371	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2372	>	table = nt;
2373	>	sc = n - (n >>> 2);
2374	>	}
2375	>	} finally {
2376	>	sizeCtl = sc;
2377	>	}
2378	>	}
2379	>	}
2380	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2381	>	break;
2382	>	else if (tab == table) {
2383	>	int rs = resizeStamp(n);
2384	>	if (U.compareAndSwapInt(this, SIZECTL, sc,
2385	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2386	>	transfer(tab, null);
2387	>	}
2388	>	}
2389	>	}
2390	>
2391	>	/**
2392	>	* Moves and/or copies the nodes in each bin to new table. See
2393	>	* above for explanation.
2394	>	*/
2395	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2396	>	int n = tab.length, stride;
2397	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2398	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2399	>	if (nextTab == null) {            // initiating
2400	>	try {
2401	>	@SuppressWarnings("unchecked")
2402	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2403	>	nextTab = nt;
2404	>	} catch (Throwable ex) {      // try to cope with OOME
2405	>	sizeCtl = Integer.MAX_VALUE;
2406	>	return;
2407	>	}
2408	>	nextTable = nextTab;
2409	>	transferIndex = n;
2410	>	}
2411	>	int nextn = nextTab.length;
2412	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2413	>	boolean advance = true;
2414	>	boolean finishing = false; // to ensure sweep before committing nextTab
2415	>	for (int i = 0, bound = 0;;) {
2416	>	Node<K,V> f; int fh;
2417	>	while (advance) {
2418	>	int nextIndex, nextBound;
2419	>	if (--i >= bound || finishing)
2420	>	advance = false;
2421	>	else if ((nextIndex = transferIndex) <= 0) {
2422	>	i = -1;
2423	>	advance = false;
2424	>	}
2425	>	else if (U.compareAndSwapInt
2426	>	(this, TRANSFERINDEX, nextIndex,
2427	>	nextBound = (nextIndex > stride ?
2428	>	nextIndex - stride : 0))) {
2429	>	bound = nextBound;
2430	>	i = nextIndex - 1;
2431	>	advance = false;
2432	>	}
2433	>	}
2434	>	if (i < 0 || i >= n || i + n >= nextn) {
2435	>	int sc;
2436	>	if (finishing) {
2437	>	nextTable = null;
2438	>	table = nextTab;
2439	>	sizeCtl = (n << 1) - (n >>> 1);
2440	>	return;
2441	>	}
2442	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2443	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2444	>	return;
2445	>	finishing = advance = true;
2446	>	i = n; // recheck before commit
2447	>	}
2448	>	}
2449	>	else if ((f = tabAt(tab, i)) == null)
2450	>	advance = casTabAt(tab, i, null, fwd);
2451	>	else if ((fh = f.hash) == MOVED)
2452	>	advance = true; // already processed
2453	>	else {
2454	>	synchronized (f) {
2455	>	if (tabAt(tab, i) == f) {
2456	>	Node<K,V> ln, hn;
2457	>	if (fh >= 0) {
2458	>	int runBit = fh & n;
2459	>	Node<K,V> lastRun = f;
2460	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2461	>	int b = p.hash & n;
2462	>	if (b != runBit) {
2463	>	runBit = b;
2464	>	lastRun = p;
2465	>	}
2466	>	}
2467	>	if (runBit == 0) {
2468	>	ln = lastRun;
2469	>	hn = null;
2470	>	}
2471	>	else {
2472	>	hn = lastRun;
2473	>	ln = null;
2474	>	}
2475	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2476	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2477	>	if ((ph & n) == 0)
2478	>	ln = new Node<K,V>(ph, pk, pv, ln);
2479	>	else
2480	>	hn = new Node<K,V>(ph, pk, pv, hn);
2481	>	}
2482	>	setTabAt(nextTab, i, ln);
2483	>	setTabAt(nextTab, i + n, hn);
2484	>	setTabAt(tab, i, fwd);
2485	>	advance = true;
2486	>	}
2487	>	else if (f instanceof TreeBin) {
2488	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2489	>	TreeNode<K,V> lo = null, loTail = null;
2490	>	TreeNode<K,V> hi = null, hiTail = null;
2491	>	int lc = 0, hc = 0;
2492	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2493	>	int h = e.hash;
2494	>	TreeNode<K,V> p = new TreeNode<K,V>
2495	>	(h, e.key, e.val, null, null);
2496	>	if ((h & n) == 0) {
2497	>	if ((p.prev = loTail) == null)
2498	>	lo = p;
2499	>	else
2500	>	loTail.next = p;
2501	>	loTail = p;
2502	>	++lc;
2503	>	}
2504	>	else {
2505	>	if ((p.prev = hiTail) == null)
2506	>	hi = p;
2507	>	else
2508	>	hiTail.next = p;
2509	>	hiTail = p;
2510	>	++hc;
2511	>	}
2512	>	}
2513	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2514	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2515	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2516	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2517	>	setTabAt(nextTab, i, ln);
2518	>	setTabAt(nextTab, i + n, hn);
2519	>	setTabAt(tab, i, fwd);
2520	>	advance = true;
2521	>	}
2522	>	}
2523	>	}
2524	>	}
2525	>	}
2526		}
2527
2528	<	/* ---------------- Iterator Support -------------- */
2528	>	/* ---------------- Counter support -------------- */
2529
2530	<	abstract class HashIterator {
2531	<	int nextSegmentIndex;
2532	<	int nextTableIndex;
2533	<	HashEntry<K,V>[] currentTable;
2534	<	HashEntry<K, V> nextEntry;
2535	<	HashEntry<K, V> lastReturned;
2530	>	/**
2531	>	* A padded cell for distributing counts.  Adapted from LongAdder
2532	>	* and Striped64.  See their internal docs for explanation.
2533	>	*/
2534	>	@jdk.internal.vm.annotation.Contended static final class CounterCell {
2535	>	volatile long value;
2536	>	CounterCell(long x) { value = x; }
2537	>	}
2538
2539	<	HashIterator() {
2540	<	nextSegmentIndex = segments.length - 1;
2541	<	nextTableIndex = -1;
2542	<	advance();
2539	>	final long sumCount() {
2540	>	CounterCell[] as = counterCells; CounterCell a;
2541	>	long sum = baseCount;
2542	>	if (as != null) {
2543	>	for (int i = 0; i < as.length; ++i) {
2544	>	if ((a = as[i]) != null)
2545	>	sum += a.value;
2546	>	}
2547	>	}
2548	>	return sum;
2549	>	}
2550	>
2551	>	// See LongAdder version for explanation
2552	>	private final void fullAddCount(long x, boolean wasUncontended) {
2553	>	int h;
2554	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2555	>	ThreadLocalRandom.localInit();      // force initialization
2556	>	h = ThreadLocalRandom.getProbe();
2557	>	wasUncontended = true;
2558	>	}
2559	>	boolean collide = false;                // True if last slot nonempty
2560	>	for (;;) {
2561	>	CounterCell[] as; CounterCell a; int n; long v;
2562	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2563	>	if ((a = as[(n - 1) & h]) == null) {
2564	>	if (cellsBusy == 0) {            // Try to attach new Cell
2565	>	CounterCell r = new CounterCell(x); // Optimistic create
2566	>	if (cellsBusy == 0 &&
2567	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2568	>	boolean created = false;
2569	>	try {               // Recheck under lock
2570	>	CounterCell[] rs; int m, j;
2571	>	if ((rs = counterCells) != null &&
2572	>	(m = rs.length) > 0 &&
2573	>	rs[j = (m - 1) & h] == null) {
2574	>	rs[j] = r;
2575	>	created = true;
2576	>	}
2577	>	} finally {
2578	>	cellsBusy = 0;
2579	>	}
2580	>	if (created)
2581	>	break;
2582	>	continue;           // Slot is now non-empty
2583	>	}
2584	>	}
2585	>	collide = false;
2586	>	}
2587	>	else if (!wasUncontended)       // CAS already known to fail
2588	>	wasUncontended = true;      // Continue after rehash
2589	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2590	>	break;
2591	>	else if (counterCells != as || n >= NCPU)
2592	>	collide = false;            // At max size or stale
2593	>	else if (!collide)
2594	>	collide = true;
2595	>	else if (cellsBusy == 0 &&
2596	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2597	>	try {
2598	>	if (counterCells == as) {// Expand table unless stale
2599	>	CounterCell[] rs = new CounterCell[n << 1];
2600	>	for (int i = 0; i < n; ++i)
2601	>	rs[i] = as[i];
2602	>	counterCells = rs;
2603	>	}
2604	>	} finally {
2605	>	cellsBusy = 0;
2606	>	}
2607	>	collide = false;
2608	>	continue;                   // Retry with expanded table
2609	>	}
2610	>	h = ThreadLocalRandom.advanceProbe(h);
2611	>	}
2612	>	else if (cellsBusy == 0 && counterCells == as &&
2613	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2614	>	boolean init = false;
2615	>	try {                           // Initialize table
2616	>	if (counterCells == as) {
2617	>	CounterCell[] rs = new CounterCell[2];
2618	>	rs[h & 1] = new CounterCell(x);
2619	>	counterCells = rs;
2620	>	init = true;
2621	>	}
2622	>	} finally {
2623	>	cellsBusy = 0;
2624	>	}
2625	>	if (init)
2626	>	break;
2627	>	}
2628	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2629	>	break;                          // Fall back on using base
2630		}
2631	+	}
2632
2633	<	public boolean hasMoreElements() { return hasNext(); }
2633	>	/* ---------------- Conversion from/to TreeBins -------------- */
2634
2635	<	final void advance() {
2636	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
2637	<	return;
2635	>	/**
2636	>	* Replaces all linked nodes in bin at given index unless table is
2637	>	* too small, in which case resizes instead.
2638	>	*/
2639	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2640	>	Node<K,V> b; int n;
2641	>	if (tab != null) {
2642	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2643	>	tryPresize(n << 1);
2644	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2645	>	synchronized (b) {
2646	>	if (tabAt(tab, index) == b) {
2647	>	TreeNode<K,V> hd = null, tl = null;
2648	>	for (Node<K,V> e = b; e != null; e = e.next) {
2649	>	TreeNode<K,V> p =
2650	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2651	>	null, null);
2652	>	if ((p.prev = tl) == null)
2653	>	hd = p;
2654	>	else
2655	>	tl.next = p;
2656	>	tl = p;
2657	>	}
2658	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2659	>	}
2660	>	}
2661	>	}
2662	>	}
2663	>	}
2664
2665	<	while (nextTableIndex >= 0) {
2666	<	if ( (nextEntry = currentTable[nextTableIndex--]) != null)
2667	<	return;
2665	>	/**
2666	>	* Returns a list of non-TreeNodes replacing those in given list.
2667	>	*/
2668	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2669	>	Node<K,V> hd = null, tl = null;
2670	>	for (Node<K,V> q = b; q != null; q = q.next) {
2671	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val);
2672	>	if (tl == null)
2673	>	hd = p;
2674	>	else
2675	>	tl.next = p;
2676	>	tl = p;
2677	>	}
2678	>	return hd;
2679	>	}
2680	>
2681	>	/* ---------------- TreeNodes -------------- */
2682	>
2683	>	/**
2684	>	* Nodes for use in TreeBins.
2685	>	*/
2686	>	static final class TreeNode<K,V> extends Node<K,V> {
2687	>	TreeNode<K,V> parent;  // red-black tree links
2688	>	TreeNode<K,V> left;
2689	>	TreeNode<K,V> right;
2690	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2691	>	boolean red;
2692	>
2693	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2694	>	TreeNode<K,V> parent) {
2695	>	super(hash, key, val, next);
2696	>	this.parent = parent;
2697	>	}
2698	>
2699	>	Node<K,V> find(int h, Object k) {
2700	>	return findTreeNode(h, k, null);
2701	>	}
2702	>
2703	>	/**
2704	>	* Returns the TreeNode (or null if not found) for the given key
2705	>	* starting at given root.
2706	>	*/
2707	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2708	>	if (k != null) {
2709	>	TreeNode<K,V> p = this;
2710	>	do {
2711	>	int ph, dir; K pk; TreeNode<K,V> q;
2712	>	TreeNode<K,V> pl = p.left, pr = p.right;
2713	>	if ((ph = p.hash) > h)
2714	>	p = pl;
2715	>	else if (ph < h)
2716	>	p = pr;
2717	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2718	>	return p;
2719	>	else if (pl == null)
2720	>	p = pr;
2721	>	else if (pr == null)
2722	>	p = pl;
2723	>	else if ((kc != null ||
2724	>	(kc = comparableClassFor(k)) != null) &&
2725	>	(dir = compareComparables(kc, k, pk)) != 0)
2726	>	p = (dir < 0) ? pl : pr;
2727	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2728	>	return q;
2729	>	else
2730	>	p = pl;
2731	>	} while (p != null);
2732		}
2733	+	return null;
2734	+	}
2735	+	}
2736	+
2737	+	/* ---------------- TreeBins -------------- */
2738	+
2739	+	/**
2740	+	* TreeNodes used at the heads of bins. TreeBins do not hold user
2741	+	* keys or values, but instead point to list of TreeNodes and
2742	+	* their root. They also maintain a parasitic read-write lock
2743	+	* forcing writers (who hold bin lock) to wait for readers (who do
2744	+	* not) to complete before tree restructuring operations.
2745	+	*/
2746	+	static final class TreeBin<K,V> extends Node<K,V> {
2747	+	TreeNode<K,V> root;
2748	+	volatile TreeNode<K,V> first;
2749	+	volatile Thread waiter;
2750	+	volatile int lockState;
2751	+	// values for lockState
2752	+	static final int WRITER = 1; // set while holding write lock
2753	+	static final int WAITER = 2; // set when waiting for write lock
2754	+	static final int READER = 4; // increment value for setting read lock
2755	+
2756	+	/**
2757	+	* Tie-breaking utility for ordering insertions when equal
2758	+	* hashCodes and non-comparable. We don't require a total
2759	+	* order, just a consistent insertion rule to maintain
2760	+	* equivalence across rebalancings. Tie-breaking further than
2761	+	* necessary simplifies testing a bit.
2762	+	*/
2763	+	static int tieBreakOrder(Object a, Object b) {
2764	+	int d;
2765	+	if (a == null || b == null ||
2766	+	(d = a.getClass().getName().
2767	+	compareTo(b.getClass().getName())) == 0)
2768	+	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2769	+	-1 : 1);
2770	+	return d;
2771	+	}
2772
2773	<	while (nextSegmentIndex >= 0) {
2774	<	Segment<K,V> seg = segments[nextSegmentIndex--];
2775	<	if (seg.count != 0) {
2776	<	currentTable = seg.table;
2777	<	for (int j = currentTable.length - 1; j >= 0; --j) {
2778	<	if ( (nextEntry = currentTable[j]) != null) {
2779	<	nextTableIndex = j - 1;
2780	<	return;
2773	>	/**
2774	>	* Creates bin with initial set of nodes headed by b.
2775	>	*/
2776	>	TreeBin(TreeNode<K,V> b) {
2777	>	super(TREEBIN, null, null);
2778	>	this.first = b;
2779	>	TreeNode<K,V> r = null;
2780	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2781	>	next = (TreeNode<K,V>)x.next;
2782	>	x.left = x.right = null;
2783	>	if (r == null) {
2784	>	x.parent = null;
2785	>	x.red = false;
2786	>	r = x;
2787	>	}
2788	>	else {
2789	>	K k = x.key;
2790	>	int h = x.hash;
2791	>	Class<?> kc = null;
2792	>	for (TreeNode<K,V> p = r;;) {
2793	>	int dir, ph;
2794	>	K pk = p.key;
2795	>	if ((ph = p.hash) > h)
2796	>	dir = -1;
2797	>	else if (ph < h)
2798	>	dir = 1;
2799	>	else if ((kc == null &&
2800	>	(kc = comparableClassFor(k)) == null) ||
2801	>	(dir = compareComparables(kc, k, pk)) == 0)
2802	>	dir = tieBreakOrder(k, pk);
2803	>	TreeNode<K,V> xp = p;
2804	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2805	>	x.parent = xp;
2806	>	if (dir <= 0)
2807	>	xp.left = x;
2808	>	else
2809	>	xp.right = x;
2810	>	r = balanceInsertion(r, x);
2811	>	break;
2812		}
2813		}
2814		}
2815		}
2816	+	this.root = r;
2817	+	assert checkInvariants(root);
2818		}
2819
2820	<	public boolean hasNext() { return nextEntry != null; }
2820	>	/**
2821	>	* Acquires write lock for tree restructuring.
2822	>	*/
2823	>	private final void lockRoot() {
2824	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2825	>	contendedLock(); // offload to separate method
2826	>	}
2827
2828	<	HashEntry<K,V> nextEntry() {
2829	<	if (nextEntry == null)
2830	<	throw new NoSuchElementException();
2831	<	lastReturned = nextEntry;
2828	>	/**
2829	>	* Releases write lock for tree restructuring.
2830	>	*/
2831	>	private final void unlockRoot() {
2832	>	lockState = 0;
2833	>	}
2834	>
2835	>	/**
2836	>	* Possibly blocks awaiting root lock.
2837	>	*/
2838	>	private final void contendedLock() {
2839	>	boolean waiting = false;
2840	>	for (int s;;) {
2841	>	if (((s = lockState) & ~WAITER) == 0) {
2842	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2843	>	if (waiting)
2844	>	waiter = null;
2845	>	return;
2846	>	}
2847	>	}
2848	>	else if ((s & WAITER) == 0) {
2849	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2850	>	waiting = true;
2851	>	waiter = Thread.currentThread();
2852	>	}
2853	>	}
2854	>	else if (waiting)
2855	>	LockSupport.park(this);
2856	>	}
2857	>	}
2858	>
2859	>	/**
2860	>	* Returns matching node or null if none. Tries to search
2861	>	* using tree comparisons from root, but continues linear
2862	>	* search when lock not available.
2863	>	*/
2864	>	final Node<K,V> find(int h, Object k) {
2865	>	if (k != null) {
2866	>	for (Node<K,V> e = first; e != null; ) {
2867	>	int s; K ek;
2868	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2869	>	if (e.hash == h &&
2870	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2871	>	return e;
2872	>	e = e.next;
2873	>	}
2874	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2875	>	s + READER)) {
2876	>	TreeNode<K,V> r, p;
2877	>	try {
2878	>	p = ((r = root) == null ? null :
2879	>	r.findTreeNode(h, k, null));
2880	>	} finally {
2881	>	Thread w;
2882	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2883	>	(READER|WAITER) && (w = waiter) != null)
2884	>	LockSupport.unpark(w);
2885	>	}
2886	>	return p;
2887	>	}
2888	>	}
2889	>	}
2890	>	return null;
2891	>	}
2892	>
2893	>	/**
2894	>	* Finds or adds a node.
2895	>	* @return null if added
2896	>	*/
2897	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2898	>	Class<?> kc = null;
2899	>	boolean searched = false;
2900	>	for (TreeNode<K,V> p = root;;) {
2901	>	int dir, ph; K pk;
2902	>	if (p == null) {
2903	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2904	>	break;
2905	>	}
2906	>	else if ((ph = p.hash) > h)
2907	>	dir = -1;
2908	>	else if (ph < h)
2909	>	dir = 1;
2910	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2911	>	return p;
2912	>	else if ((kc == null &&
2913	>	(kc = comparableClassFor(k)) == null) ||
2914	>	(dir = compareComparables(kc, k, pk)) == 0) {
2915	>	if (!searched) {
2916	>	TreeNode<K,V> q, ch;
2917	>	searched = true;
2918	>	if (((ch = p.left) != null &&
2919	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2920	>	((ch = p.right) != null &&
2921	>	(q = ch.findTreeNode(h, k, kc)) != null))
2922	>	return q;
2923	>	}
2924	>	dir = tieBreakOrder(k, pk);
2925	>	}
2926	>
2927	>	TreeNode<K,V> xp = p;
2928	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2929	>	TreeNode<K,V> x, f = first;
2930	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2931	>	if (f != null)
2932	>	f.prev = x;
2933	>	if (dir <= 0)
2934	>	xp.left = x;
2935	>	else
2936	>	xp.right = x;
2937	>	if (!xp.red)
2938	>	x.red = true;
2939	>	else {
2940	>	lockRoot();
2941	>	try {
2942	>	root = balanceInsertion(root, x);
2943	>	} finally {
2944	>	unlockRoot();
2945	>	}
2946	>	}
2947	>	break;
2948	>	}
2949	>	}
2950	>	assert checkInvariants(root);
2951	>	return null;
2952	>	}
2953	>
2954	>	/**
2955	>	* Removes the given node, that must be present before this
2956	>	* call.  This is messier than typical red-black deletion code
2957	>	* because we cannot swap the contents of an interior node
2958	>	* with a leaf successor that is pinned by "next" pointers
2959	>	* that are accessible independently of lock. So instead we
2960	>	* swap the tree linkages.
2961	>	*
2962	>	* @return true if now too small, so should be untreeified
2963	>	*/
2964	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2965	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2966	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2967	>	TreeNode<K,V> r, rl;
2968	>	if (pred == null)
2969	>	first = next;
2970	>	else
2971	>	pred.next = next;
2972	>	if (next != null)
2973	>	next.prev = pred;
2974	>	if (first == null) {
2975	>	root = null;
2976	>	return true;
2977	>	}
2978	>	if ((r = root) == null || r.right == null || // too small
2979	>	(rl = r.left) == null || rl.left == null)
2980	>	return true;
2981	>	lockRoot();
2982	>	try {
2983	>	TreeNode<K,V> replacement;
2984	>	TreeNode<K,V> pl = p.left;
2985	>	TreeNode<K,V> pr = p.right;
2986	>	if (pl != null && pr != null) {
2987	>	TreeNode<K,V> s = pr, sl;
2988	>	while ((sl = s.left) != null) // find successor
2989	>	s = sl;
2990	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2991	>	TreeNode<K,V> sr = s.right;
2992	>	TreeNode<K,V> pp = p.parent;
2993	>	if (s == pr) { // p was s's direct parent
2994	>	p.parent = s;
2995	>	s.right = p;
2996	>	}
2997	>	else {
2998	>	TreeNode<K,V> sp = s.parent;
2999	>	if ((p.parent = sp) != null) {
3000	>	if (s == sp.left)
3001	>	sp.left = p;
3002	>	else
3003	>	sp.right = p;
3004	>	}
3005	>	if ((s.right = pr) != null)
3006	>	pr.parent = s;
3007	>	}
3008	>	p.left = null;
3009	>	if ((p.right = sr) != null)
3010	>	sr.parent = p;
3011	>	if ((s.left = pl) != null)
3012	>	pl.parent = s;
3013	>	if ((s.parent = pp) == null)
3014	>	r = s;
3015	>	else if (p == pp.left)
3016	>	pp.left = s;
3017	>	else
3018	>	pp.right = s;
3019	>	if (sr != null)
3020	>	replacement = sr;
3021	>	else
3022	>	replacement = p;
3023	>	}
3024	>	else if (pl != null)
3025	>	replacement = pl;
3026	>	else if (pr != null)
3027	>	replacement = pr;
3028	>	else
3029	>	replacement = p;
3030	>	if (replacement != p) {
3031	>	TreeNode<K,V> pp = replacement.parent = p.parent;
3032	>	if (pp == null)
3033	>	r = replacement;
3034	>	else if (p == pp.left)
3035	>	pp.left = replacement;
3036	>	else
3037	>	pp.right = replacement;
3038	>	p.left = p.right = p.parent = null;
3039	>	}
3040	>
3041	>	root = (p.red) ? r : balanceDeletion(r, replacement);
3042	>
3043	>	if (p == replacement) {  // detach pointers
3044	>	TreeNode<K,V> pp;
3045	>	if ((pp = p.parent) != null) {
3046	>	if (p == pp.left)
3047	>	pp.left = null;
3048	>	else if (p == pp.right)
3049	>	pp.right = null;
3050	>	p.parent = null;
3051	>	}
3052	>	}
3053	>	} finally {
3054	>	unlockRoot();
3055	>	}
3056	>	assert checkInvariants(root);
3057	>	return false;
3058	>	}
3059	>
3060	>	/* ------------------------------------------------------------ */
3061	>	// Red-black tree methods, all adapted from CLR
3062	>
3063	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3064	>	TreeNode<K,V> p) {
3065	>	TreeNode<K,V> r, pp, rl;
3066	>	if (p != null && (r = p.right) != null) {
3067	>	if ((rl = p.right = r.left) != null)
3068	>	rl.parent = p;
3069	>	if ((pp = r.parent = p.parent) == null)
3070	>	(root = r).red = false;
3071	>	else if (pp.left == p)
3072	>	pp.left = r;
3073	>	else
3074	>	pp.right = r;
3075	>	r.left = p;
3076	>	p.parent = r;
3077	>	}
3078	>	return root;
3079	>	}
3080	>
3081	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3082	>	TreeNode<K,V> p) {
3083	>	TreeNode<K,V> l, pp, lr;
3084	>	if (p != null && (l = p.left) != null) {
3085	>	if ((lr = p.left = l.right) != null)
3086	>	lr.parent = p;
3087	>	if ((pp = l.parent = p.parent) == null)
3088	>	(root = l).red = false;
3089	>	else if (pp.right == p)
3090	>	pp.right = l;
3091	>	else
3092	>	pp.left = l;
3093	>	l.right = p;
3094	>	p.parent = l;
3095	>	}
3096	>	return root;
3097	>	}
3098	>
3099	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3100	>	TreeNode<K,V> x) {
3101	>	x.red = true;
3102	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3103	>	if ((xp = x.parent) == null) {
3104	>	x.red = false;
3105	>	return x;
3106	>	}
3107	>	else if (!xp.red || (xpp = xp.parent) == null)
3108	>	return root;
3109	>	if (xp == (xppl = xpp.left)) {
3110	>	if ((xppr = xpp.right) != null && xppr.red) {
3111	>	xppr.red = false;
3112	>	xp.red = false;
3113	>	xpp.red = true;
3114	>	x = xpp;
3115	>	}
3116	>	else {
3117	>	if (x == xp.right) {
3118	>	root = rotateLeft(root, x = xp);
3119	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3120	>	}
3121	>	if (xp != null) {
3122	>	xp.red = false;
3123	>	if (xpp != null) {
3124	>	xpp.red = true;
3125	>	root = rotateRight(root, xpp);
3126	>	}
3127	>	}
3128	>	}
3129	>	}
3130	>	else {
3131	>	if (xppl != null && xppl.red) {
3132	>	xppl.red = false;
3133	>	xp.red = false;
3134	>	xpp.red = true;
3135	>	x = xpp;
3136	>	}
3137	>	else {
3138	>	if (x == xp.left) {
3139	>	root = rotateRight(root, x = xp);
3140	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3141	>	}
3142	>	if (xp != null) {
3143	>	xp.red = false;
3144	>	if (xpp != null) {
3145	>	xpp.red = true;
3146	>	root = rotateLeft(root, xpp);
3147	>	}
3148	>	}
3149	>	}
3150	>	}
3151	>	}
3152	>	}
3153	>
3154	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3155	>	TreeNode<K,V> x) {
3156	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3157	>	if (x == null || x == root)
3158	>	return root;
3159	>	else if ((xp = x.parent) == null) {
3160	>	x.red = false;
3161	>	return x;
3162	>	}
3163	>	else if (x.red) {
3164	>	x.red = false;
3165	>	return root;
3166	>	}
3167	>	else if ((xpl = xp.left) == x) {
3168	>	if ((xpr = xp.right) != null && xpr.red) {
3169	>	xpr.red = false;
3170	>	xp.red = true;
3171	>	root = rotateLeft(root, xp);
3172	>	xpr = (xp = x.parent) == null ? null : xp.right;
3173	>	}
3174	>	if (xpr == null)
3175	>	x = xp;
3176	>	else {
3177	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3178	>	if ((sr == null || !sr.red) &&
3179	>	(sl == null || !sl.red)) {
3180	>	xpr.red = true;
3181	>	x = xp;
3182	>	}
3183	>	else {
3184	>	if (sr == null || !sr.red) {
3185	>	if (sl != null)
3186	>	sl.red = false;
3187	>	xpr.red = true;
3188	>	root = rotateRight(root, xpr);
3189	>	xpr = (xp = x.parent) == null ?
3190	>	null : xp.right;
3191	>	}
3192	>	if (xpr != null) {
3193	>	xpr.red = (xp == null) ? false : xp.red;
3194	>	if ((sr = xpr.right) != null)
3195	>	sr.red = false;
3196	>	}
3197	>	if (xp != null) {
3198	>	xp.red = false;
3199	>	root = rotateLeft(root, xp);
3200	>	}
3201	>	x = root;
3202	>	}
3203	>	}
3204	>	}
3205	>	else { // symmetric
3206	>	if (xpl != null && xpl.red) {
3207	>	xpl.red = false;
3208	>	xp.red = true;
3209	>	root = rotateRight(root, xp);
3210	>	xpl = (xp = x.parent) == null ? null : xp.left;
3211	>	}
3212	>	if (xpl == null)
3213	>	x = xp;
3214	>	else {
3215	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3216	>	if ((sl == null || !sl.red) &&
3217	>	(sr == null || !sr.red)) {
3218	>	xpl.red = true;
3219	>	x = xp;
3220	>	}
3221	>	else {
3222	>	if (sl == null || !sl.red) {
3223	>	if (sr != null)
3224	>	sr.red = false;
3225	>	xpl.red = true;
3226	>	root = rotateLeft(root, xpl);
3227	>	xpl = (xp = x.parent) == null ?
3228	>	null : xp.left;
3229	>	}
3230	>	if (xpl != null) {
3231	>	xpl.red = (xp == null) ? false : xp.red;
3232	>	if ((sl = xpl.left) != null)
3233	>	sl.red = false;
3234	>	}
3235	>	if (xp != null) {
3236	>	xp.red = false;
3237	>	root = rotateRight(root, xp);
3238	>	}
3239	>	x = root;
3240	>	}
3241	>	}
3242	>	}
3243	>	}
3244	>	}
3245	>
3246	>	/**
3247	>	* Checks invariants recursively for the tree of Nodes rooted at t.
3248	>	*/
3249	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3250	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3251	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3252	>	if (tb != null && tb.next != t)
3253	>	return false;
3254	>	if (tn != null && tn.prev != t)
3255	>	return false;
3256	>	if (tp != null && t != tp.left && t != tp.right)
3257	>	return false;
3258	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3259	>	return false;
3260	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3261	>	return false;
3262	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3263	>	return false;
3264	>	if (tl != null && !checkInvariants(tl))
3265	>	return false;
3266	>	if (tr != null && !checkInvariants(tr))
3267	>	return false;
3268	>	return true;
3269	>	}
3270	>
3271	>	private static final Unsafe U = Unsafe.getUnsafe();
3272	>	private static final long LOCKSTATE;
3273	>	static {
3274	>	try {
3275	>	LOCKSTATE = U.objectFieldOffset
3276	>	(TreeBin.class.getDeclaredField("lockState"));
3277	>	} catch (ReflectiveOperationException e) {
3278	>	throw new Error(e);
3279	>	}
3280	>	}
3281	>	}
3282	>
3283	>	/* ----------------Table Traversal -------------- */
3284	>
3285	>	/**
3286	>	* Records the table, its length, and current traversal index for a
3287	>	* traverser that must process a region of a forwarded table before
3288	>	* proceeding with current table.
3289	>	*/
3290	>	static final class TableStack<K,V> {
3291	>	int length;
3292	>	int index;
3293	>	Node<K,V>[] tab;
3294	>	TableStack<K,V> next;
3295	>	}
3296	>
3297	>	/**
3298	>	* Encapsulates traversal for methods such as containsValue; also
3299	>	* serves as a base class for other iterators and spliterators.
3300	>	*
3301	>	* Method advance visits once each still-valid node that was
3302	>	* reachable upon iterator construction. It might miss some that
3303	>	* were added to a bin after the bin was visited, which is OK wrt
3304	>	* consistency guarantees. Maintaining this property in the face
3305	>	* of possible ongoing resizes requires a fair amount of
3306	>	* bookkeeping state that is difficult to optimize away amidst
3307	>	* volatile accesses.  Even so, traversal maintains reasonable
3308	>	* throughput.
3309	>	*
3310	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3311	>	* However, if the table has been resized, then all future steps
3312	>	* must traverse both the bin at the current index as well as at
3313	>	* (index + baseSize); and so on for further resizings. To
3314	>	* paranoically cope with potential sharing by users of iterators
3315	>	* across threads, iteration terminates if a bounds checks fails
3316	>	* for a table read.
3317	>	*/
3318	>	static class Traverser<K,V> {
3319	>	Node<K,V>[] tab;        // current table; updated if resized
3320	>	Node<K,V> next;         // the next entry to use
3321	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3322	>	int index;              // index of bin to use next
3323	>	int baseIndex;          // current index of initial table
3324	>	int baseLimit;          // index bound for initial table
3325	>	final int baseSize;     // initial table size
3326	>
3327	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3328	>	this.tab = tab;
3329	>	this.baseSize = size;
3330	>	this.baseIndex = this.index = index;
3331	>	this.baseLimit = limit;
3332	>	this.next = null;
3333	>	}
3334	>
3335	>	/**
3336	>	* Advances if possible, returning next valid node, or null if none.
3337	>	*/
3338	>	final Node<K,V> advance() {
3339	>	Node<K,V> e;
3340	>	if ((e = next) != null)
3341	>	e = e.next;
3342	>	for (;;) {
3343	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3344	>	if (e != null)
3345	>	return next = e;
3346	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3347	>	(n = t.length) <= (i = index) || i < 0)
3348	>	return next = null;
3349	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3350	>	if (e instanceof ForwardingNode) {
3351	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3352	>	e = null;
3353	>	pushState(t, i, n);
3354	>	continue;
3355	>	}
3356	>	else if (e instanceof TreeBin)
3357	>	e = ((TreeBin<K,V>)e).first;
3358	>	else
3359	>	e = null;
3360	>	}
3361	>	if (stack != null)
3362	>	recoverState(n);
3363	>	else if ((index = i + baseSize) >= n)
3364	>	index = ++baseIndex; // visit upper slots if present
3365	>	}
3366	>	}
3367	>
3368	>	/**
3369	>	* Saves traversal state upon encountering a forwarding node.
3370	>	*/
3371	>	private void pushState(Node<K,V>[] t, int i, int n) {
3372	>	TableStack<K,V> s = spare;  // reuse if possible
3373	>	if (s != null)
3374	>	spare = s.next;
3375	>	else
3376	>	s = new TableStack<K,V>();
3377	>	s.tab = t;
3378	>	s.length = n;
3379	>	s.index = i;
3380	>	s.next = stack;
3381	>	stack = s;
3382	>	}
3383	>
3384	>	/**
3385	>	* Possibly pops traversal state.
3386	>	*
3387	>	* @param n length of current table
3388	>	*/
3389	>	private void recoverState(int n) {
3390	>	TableStack<K,V> s; int len;
3391	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3392	>	n = len;
3393	>	index = s.index;
3394	>	tab = s.tab;
3395	>	s.tab = null;
3396	>	TableStack<K,V> next = s.next;
3397	>	s.next = spare; // save for reuse
3398	>	stack = next;
3399	>	spare = s;
3400	>	}
3401	>	if (s == null && (index += baseSize) >= n)
3402	>	index = ++baseIndex;
3403	>	}
3404	>	}
3405	>
3406	>	/**
3407	>	* Base of key, value, and entry Iterators. Adds fields to
3408	>	* Traverser to support iterator.remove.
3409	>	*/
3410	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3411	>	final ConcurrentHashMap<K,V> map;
3412	>	Node<K,V> lastReturned;
3413	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3414	>	ConcurrentHashMap<K,V> map) {
3415	>	super(tab, size, index, limit);
3416	>	this.map = map;
3417		advance();
1098	–	return lastReturned;
3418		}
3419
3420	<	public void remove() {
3421	<	if (lastReturned == null)
3420	>	public final boolean hasNext() { return next != null; }
3421	>	public final boolean hasMoreElements() { return next != null; }
3422	>
3423	>	public final void remove() {
3424	>	Node<K,V> p;
3425	>	if ((p = lastReturned) == null)
3426		throw new IllegalStateException();
1104	–	ConcurrentHashMap.this.remove(lastReturned.key);
3427		lastReturned = null;
3428	+	map.replaceNode(p.key, null, null);
3429		}
3430		}
3431
3432	<	final class KeyIterator
3433	<	extends HashIterator
3434	<	implements Iterator<K>, Enumeration<K>
3435	<	{
3436	<	public K next()        { return super.nextEntry().key; }
3437	<	public K nextElement() { return super.nextEntry().key; }
3432	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3433	>	implements Iterator<K>, Enumeration<K> {
3434	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3435	>	ConcurrentHashMap<K,V> map) {
3436	>	super(tab, index, size, limit, map);
3437	>	}
3438	>
3439	>	public final K next() {
3440	>	Node<K,V> p;
3441	>	if ((p = next) == null)
3442	>	throw new NoSuchElementException();
3443	>	K k = p.key;
3444	>	lastReturned = p;
3445	>	advance();
3446	>	return k;
3447	>	}
3448	>
3449	>	public final K nextElement() { return next(); }
3450		}
3451
3452	<	final class ValueIterator
3453	<	extends HashIterator
3454	<	implements Iterator<V>, Enumeration<V>
3455	<	{
3456	<	public V next()        { return super.nextEntry().value; }
3457	<	public V nextElement() { return super.nextEntry().value; }
3452	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3453	>	implements Iterator<V>, Enumeration<V> {
3454	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3455	>	ConcurrentHashMap<K,V> map) {
3456	>	super(tab, index, size, limit, map);
3457	>	}
3458	>
3459	>	public final V next() {
3460	>	Node<K,V> p;
3461	>	if ((p = next) == null)
3462	>	throw new NoSuchElementException();
3463	>	V v = p.val;
3464	>	lastReturned = p;
3465	>	advance();
3466	>	return v;
3467	>	}
3468	>
3469	>	public final V nextElement() { return next(); }
3470	>	}
3471	>
3472	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3473	>	implements Iterator<Map.Entry<K,V>> {
3474	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3475	>	ConcurrentHashMap<K,V> map) {
3476	>	super(tab, index, size, limit, map);
3477	>	}
3478	>
3479	>	public final Map.Entry<K,V> next() {
3480	>	Node<K,V> p;
3481	>	if ((p = next) == null)
3482	>	throw new NoSuchElementException();
3483	>	K k = p.key;
3484	>	V v = p.val;
3485	>	lastReturned = p;
3486	>	advance();
3487	>	return new MapEntry<K,V>(k, v, map);
3488	>	}
3489		}
3490
3491		/**
3492	<	* Custom Entry class used by EntryIterator.next(), that relays
1127	<	* setValue changes to the underlying map.
3492	>	* Exported Entry for EntryIterator.
3493		*/
3494	<	final class WriteThroughEntry
3495	<	extends AbstractMap.SimpleEntry<K,V>
3496	<	{
3497	<	WriteThroughEntry(K k, V v) {
3498	<	super(k,v);
3494	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3495	>	final K key; // non-null
3496	>	V val;       // non-null
3497	>	final ConcurrentHashMap<K,V> map;
3498	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3499	>	this.key = key;
3500	>	this.val = val;
3501	>	this.map = map;
3502	>	}
3503	>	public K getKey()        { return key; }
3504	>	public V getValue()      { return val; }
3505	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3506	>	public String toString() {
3507	>	return Helpers.mapEntryToString(key, val);
3508	>	}
3509	>
3510	>	public boolean equals(Object o) {
3511	>	Object k, v; Map.Entry<?,?> e;
3512	>	return ((o instanceof Map.Entry) &&
3513	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3514	>	(v = e.getValue()) != null &&
3515	>	(k == key || k.equals(key)) &&
3516	>	(v == val || v.equals(val)));
3517		}
3518
3519		/**
3520	<	* Set our entry's value and write through to the map. The
3521	<	* value to return is somewhat arbitrary here. Since a
3522	<	* WriteThroughEntry does not necessarily track asynchronous
3523	<	* changes, the most recent "previous" value could be
3524	<	* different from what we return (or could even have been
3525	<	* removed in which case the put will re-establish). We do not
1143	<	* and cannot guarantee more.
3520	>	* Sets our entry's value and writes through to the map. The
3521	>	* value to return is somewhat arbitrary here. Since we do not
3522	>	* necessarily track asynchronous changes, the most recent
3523	>	* "previous" value could be different from what we return (or
3524	>	* could even have been removed, in which case the put will
3525	>	* re-establish). We do not and cannot guarantee more.
3526		*/
3527	<	public V setValue(V value) {
3527	>	public V setValue(V value) {
3528		if (value == null) throw new NullPointerException();
3529	<	V v = super.setValue(value);
3530	<	ConcurrentHashMap.this.put(getKey(), value);
3529	>	V v = val;
3530	>	val = value;
3531	>	map.put(key, value);
3532		return v;
3533		}
3534		}
3535
3536	<	final class EntryIterator
3537	<	extends HashIterator
3538	<	implements Iterator<Entry<K,V>>
3539	<	{
3540	<	public Map.Entry<K,V> next() {
3541	<	HashEntry<K,V> e = super.nextEntry();
3542	<	return new WriteThroughEntry(e.key, e.value);
3536	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3537	>	implements Spliterator<K> {
3538	>	long est;               // size estimate
3539	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3540	>	long est) {
3541	>	super(tab, size, index, limit);
3542	>	this.est = est;
3543	>	}
3544	>
3545	>	public KeySpliterator<K,V> trySplit() {
3546	>	int i, f, h;
3547	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3548	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3549	>	f, est >>>= 1);
3550	>	}
3551	>
3552	>	public void forEachRemaining(Consumer<? super K> action) {
3553	>	if (action == null) throw new NullPointerException();
3554	>	for (Node<K,V> p; (p = advance()) != null;)
3555	>	action.accept(p.key);
3556	>	}
3557	>
3558	>	public boolean tryAdvance(Consumer<? super K> action) {
3559	>	if (action == null) throw new NullPointerException();
3560	>	Node<K,V> p;
3561	>	if ((p = advance()) == null)
3562	>	return false;
3563	>	action.accept(p.key);
3564	>	return true;
3565	>	}
3566	>
3567	>	public long estimateSize() { return est; }
3568	>
3569	>	public int characteristics() {
3570	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3571	>	Spliterator.NONNULL;
3572		}
3573		}
3574
3575	<	final class KeySet extends AbstractSet<K> {
3576	<	public Iterator<K> iterator() {
3577	<	return new KeyIterator();
3575	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3576	>	implements Spliterator<V> {
3577	>	long est;               // size estimate
3578	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3579	>	long est) {
3580	>	super(tab, size, index, limit);
3581	>	this.est = est;
3582	>	}
3583	>
3584	>	public ValueSpliterator<K,V> trySplit() {
3585	>	int i, f, h;
3586	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3587	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3588	>	f, est >>>= 1);
3589	>	}
3590	>
3591	>	public void forEachRemaining(Consumer<? super V> action) {
3592	>	if (action == null) throw new NullPointerException();
3593	>	for (Node<K,V> p; (p = advance()) != null;)
3594	>	action.accept(p.val);
3595	>	}
3596	>
3597	>	public boolean tryAdvance(Consumer<? super V> action) {
3598	>	if (action == null) throw new NullPointerException();
3599	>	Node<K,V> p;
3600	>	if ((p = advance()) == null)
3601	>	return false;
3602	>	action.accept(p.val);
3603	>	return true;
3604		}
3605	<	public int size() {
3606	<	return ConcurrentHashMap.this.size();
3605	>
3606	>	public long estimateSize() { return est; }
3607	>
3608	>	public int characteristics() {
3609	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3610		}
3611	<	public boolean contains(Object o) {
3612	<	return ConcurrentHashMap.this.containsKey(o);
3611	>	}
3612	>
3613	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3614	>	implements Spliterator<Map.Entry<K,V>> {
3615	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3616	>	long est;               // size estimate
3617	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3618	>	long est, ConcurrentHashMap<K,V> map) {
3619	>	super(tab, size, index, limit);
3620	>	this.map = map;
3621	>	this.est = est;
3622	>	}
3623	>
3624	>	public EntrySpliterator<K,V> trySplit() {
3625	>	int i, f, h;
3626	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3627	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3628	>	f, est >>>= 1, map);
3629	>	}
3630	>
3631	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3632	>	if (action == null) throw new NullPointerException();
3633	>	for (Node<K,V> p; (p = advance()) != null; )
3634	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3635	>	}
3636	>
3637	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3638	>	if (action == null) throw new NullPointerException();
3639	>	Node<K,V> p;
3640	>	if ((p = advance()) == null)
3641	>	return false;
3642	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3643	>	return true;
3644		}
3645	<	public boolean remove(Object o) {
3646	<	return ConcurrentHashMap.this.remove(o) != null;
3645	>
3646	>	public long estimateSize() { return est; }
3647	>
3648	>	public int characteristics() {
3649	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3650	>	Spliterator.NONNULL;
3651		}
3652	<	public void clear() {
3653	<	ConcurrentHashMap.this.clear();
3652	>	}
3653	>
3654	>	// Parallel bulk operations
3655	>
3656	>	/**
3657	>	* Computes initial batch value for bulk tasks. The returned value
3658	>	* is approximately exp2 of the number of times (minus one) to
3659	>	* split task by two before executing leaf action. This value is
3660	>	* faster to compute and more convenient to use as a guide to
3661	>	* splitting than is the depth, since it is used while dividing by
3662	>	* two anyway.
3663	>	*/
3664	>	final int batchFor(long b) {
3665	>	long n;
3666	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3667	>	return 0;
3668	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3669	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3670	>	}
3671	>
3672	>	/**
3673	>	* Performs the given action for each (key, value).
3674	>	*
3675	>	* @param parallelismThreshold the (estimated) number of elements
3676	>	* needed for this operation to be executed in parallel
3677	>	* @param action the action
3678	>	* @since 1.8
3679	>	*/
3680	>	public void forEach(long parallelismThreshold,
3681	>	BiConsumer<? super K,? super V> action) {
3682	>	if (action == null) throw new NullPointerException();
3683	>	new ForEachMappingTask<K,V>
3684	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3685	>	action).invoke();
3686	>	}
3687	>
3688	>	/**
3689	>	* Performs the given action for each non-null transformation
3690	>	* of each (key, value).
3691	>	*
3692	>	* @param parallelismThreshold the (estimated) number of elements
3693	>	* needed for this operation to be executed in parallel
3694	>	* @param transformer a function returning the transformation
3695	>	* for an element, or null if there is no transformation (in
3696	>	* which case the action is not applied)
3697	>	* @param action the action
3698	>	* @param <U> the return type of the transformer
3699	>	* @since 1.8
3700	>	*/
3701	>	public <U> void forEach(long parallelismThreshold,
3702	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3703	>	Consumer<? super U> action) {
3704	>	if (transformer == null || action == null)
3705	>	throw new NullPointerException();
3706	>	new ForEachTransformedMappingTask<K,V,U>
3707	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3708	>	transformer, action).invoke();
3709	>	}
3710	>
3711	>	/**
3712	>	* Returns a non-null result from applying the given search
3713	>	* function on each (key, value), or null if none.  Upon
3714	>	* success, further element processing is suppressed and the
3715	>	* results of any other parallel invocations of the search
3716	>	* function are ignored.
3717	>	*
3718	>	* @param parallelismThreshold the (estimated) number of elements
3719	>	* needed for this operation to be executed in parallel
3720	>	* @param searchFunction a function returning a non-null
3721	>	* result on success, else null
3722	>	* @param <U> the return type of the search function
3723	>	* @return a non-null result from applying the given search
3724	>	* function on each (key, value), or null if none
3725	>	* @since 1.8
3726	>	*/
3727	>	public <U> U search(long parallelismThreshold,
3728	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3729	>	if (searchFunction == null) throw new NullPointerException();
3730	>	return new SearchMappingsTask<K,V,U>
3731	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3732	>	searchFunction, new AtomicReference<U>()).invoke();
3733	>	}
3734	>
3735	>	/**
3736	>	* Returns the result of accumulating the given transformation
3737	>	* of all (key, value) pairs using the given reducer to
3738	>	* combine values, or null if none.
3739	>	*
3740	>	* @param parallelismThreshold the (estimated) number of elements
3741	>	* needed for this operation to be executed in parallel
3742	>	* @param transformer a function returning the transformation
3743	>	* for an element, or null if there is no transformation (in
3744	>	* which case it is not combined)
3745	>	* @param reducer a commutative associative combining function
3746	>	* @param <U> the return type of the transformer
3747	>	* @return the result of accumulating the given transformation
3748	>	* of all (key, value) pairs
3749	>	* @since 1.8
3750	>	*/
3751	>	public <U> U reduce(long parallelismThreshold,
3752	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3753	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3754	>	if (transformer == null || reducer == null)
3755	>	throw new NullPointerException();
3756	>	return new MapReduceMappingsTask<K,V,U>
3757	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3758	>	null, transformer, reducer).invoke();
3759	>	}
3760	>
3761	>	/**
3762	>	* Returns the result of accumulating the given transformation
3763	>	* of all (key, value) pairs using the given reducer to
3764	>	* combine values, and the given basis as an identity value.
3765	>	*
3766	>	* @param parallelismThreshold the (estimated) number of elements
3767	>	* needed for this operation to be executed in parallel
3768	>	* @param transformer a function returning the transformation
3769	>	* for an element
3770	>	* @param basis the identity (initial default value) for the reduction
3771	>	* @param reducer a commutative associative combining function
3772	>	* @return the result of accumulating the given transformation
3773	>	* of all (key, value) pairs
3774	>	* @since 1.8
3775	>	*/
3776	>	public double reduceToDouble(long parallelismThreshold,
3777	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3778	>	double basis,
3779	>	DoubleBinaryOperator reducer) {
3780	>	if (transformer == null || reducer == null)
3781	>	throw new NullPointerException();
3782	>	return new MapReduceMappingsToDoubleTask<K,V>
3783	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3784	>	null, transformer, basis, reducer).invoke();
3785	>	}
3786	>
3787	>	/**
3788	>	* Returns the result of accumulating the given transformation
3789	>	* of all (key, value) pairs using the given reducer to
3790	>	* combine values, and the given basis as an identity value.
3791	>	*
3792	>	* @param parallelismThreshold the (estimated) number of elements
3793	>	* needed for this operation to be executed in parallel
3794	>	* @param transformer a function returning the transformation
3795	>	* for an element
3796	>	* @param basis the identity (initial default value) for the reduction
3797	>	* @param reducer a commutative associative combining function
3798	>	* @return the result of accumulating the given transformation
3799	>	* of all (key, value) pairs
3800	>	* @since 1.8
3801	>	*/
3802	>	public long reduceToLong(long parallelismThreshold,
3803	>	ToLongBiFunction<? super K, ? super V> transformer,
3804	>	long basis,
3805	>	LongBinaryOperator reducer) {
3806	>	if (transformer == null || reducer == null)
3807	>	throw new NullPointerException();
3808	>	return new MapReduceMappingsToLongTask<K,V>
3809	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3810	>	null, transformer, basis, reducer).invoke();
3811	>	}
3812	>
3813	>	/**
3814	>	* Returns the result of accumulating the given transformation
3815	>	* of all (key, value) pairs using the given reducer to
3816	>	* combine values, and the given basis as an identity value.
3817	>	*
3818	>	* @param parallelismThreshold the (estimated) number of elements
3819	>	* needed for this operation to be executed in parallel
3820	>	* @param transformer a function returning the transformation
3821	>	* for an element
3822	>	* @param basis the identity (initial default value) for the reduction
3823	>	* @param reducer a commutative associative combining function
3824	>	* @return the result of accumulating the given transformation
3825	>	* of all (key, value) pairs
3826	>	* @since 1.8
3827	>	*/
3828	>	public int reduceToInt(long parallelismThreshold,
3829	>	ToIntBiFunction<? super K, ? super V> transformer,
3830	>	int basis,
3831	>	IntBinaryOperator reducer) {
3832	>	if (transformer == null || reducer == null)
3833	>	throw new NullPointerException();
3834	>	return new MapReduceMappingsToIntTask<K,V>
3835	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3836	>	null, transformer, basis, reducer).invoke();
3837	>	}
3838	>
3839	>	/**
3840	>	* Performs the given action for each key.
3841	>	*
3842	>	* @param parallelismThreshold the (estimated) number of elements
3843	>	* needed for this operation to be executed in parallel
3844	>	* @param action the action
3845	>	* @since 1.8
3846	>	*/
3847	>	public void forEachKey(long parallelismThreshold,
3848	>	Consumer<? super K> action) {
3849	>	if (action == null) throw new NullPointerException();
3850	>	new ForEachKeyTask<K,V>
3851	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3852	>	action).invoke();
3853	>	}
3854	>
3855	>	/**
3856	>	* Performs the given action for each non-null transformation
3857	>	* of each key.
3858	>	*
3859	>	* @param parallelismThreshold the (estimated) number of elements
3860	>	* needed for this operation to be executed in parallel
3861	>	* @param transformer a function returning the transformation
3862	>	* for an element, or null if there is no transformation (in
3863	>	* which case the action is not applied)
3864	>	* @param action the action
3865	>	* @param <U> the return type of the transformer
3866	>	* @since 1.8
3867	>	*/
3868	>	public <U> void forEachKey(long parallelismThreshold,
3869	>	Function<? super K, ? extends U> transformer,
3870	>	Consumer<? super U> action) {
3871	>	if (transformer == null || action == null)
3872	>	throw new NullPointerException();
3873	>	new ForEachTransformedKeyTask<K,V,U>
3874	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3875	>	transformer, action).invoke();
3876	>	}
3877	>
3878	>	/**
3879	>	* Returns a non-null result from applying the given search
3880	>	* function on each key, or null if none. Upon success,
3881	>	* further element processing is suppressed and the results of
3882	>	* any other parallel invocations of the search function are
3883	>	* ignored.
3884	>	*
3885	>	* @param parallelismThreshold the (estimated) number of elements
3886	>	* needed for this operation to be executed in parallel
3887	>	* @param searchFunction a function returning a non-null
3888	>	* result on success, else null
3889	>	* @param <U> the return type of the search function
3890	>	* @return a non-null result from applying the given search
3891	>	* function on each key, or null if none
3892	>	* @since 1.8
3893	>	*/
3894	>	public <U> U searchKeys(long parallelismThreshold,
3895	>	Function<? super K, ? extends U> searchFunction) {
3896	>	if (searchFunction == null) throw new NullPointerException();
3897	>	return new SearchKeysTask<K,V,U>
3898	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3899	>	searchFunction, new AtomicReference<U>()).invoke();
3900	>	}
3901	>
3902	>	/**
3903	>	* Returns the result of accumulating all keys using the given
3904	>	* reducer to combine values, or null if none.
3905	>	*
3906	>	* @param parallelismThreshold the (estimated) number of elements
3907	>	* needed for this operation to be executed in parallel
3908	>	* @param reducer a commutative associative combining function
3909	>	* @return the result of accumulating all keys using the given
3910	>	* reducer to combine values, or null if none
3911	>	* @since 1.8
3912	>	*/
3913	>	public K reduceKeys(long parallelismThreshold,
3914	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3915	>	if (reducer == null) throw new NullPointerException();
3916	>	return new ReduceKeysTask<K,V>
3917	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3918	>	null, reducer).invoke();
3919	>	}
3920	>
3921	>	/**
3922	>	* Returns the result of accumulating the given transformation
3923	>	* of all keys using the given reducer to combine values, or
3924	>	* null if none.
3925	>	*
3926	>	* @param parallelismThreshold the (estimated) number of elements
3927	>	* needed for this operation to be executed in parallel
3928	>	* @param transformer a function returning the transformation
3929	>	* for an element, or null if there is no transformation (in
3930	>	* which case it is not combined)
3931	>	* @param reducer a commutative associative combining function
3932	>	* @param <U> the return type of the transformer
3933	>	* @return the result of accumulating the given transformation
3934	>	* of all keys
3935	>	* @since 1.8
3936	>	*/
3937	>	public <U> U reduceKeys(long parallelismThreshold,
3938	>	Function<? super K, ? extends U> transformer,
3939	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3940	>	if (transformer == null || reducer == null)
3941	>	throw new NullPointerException();
3942	>	return new MapReduceKeysTask<K,V,U>
3943	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3944	>	null, transformer, reducer).invoke();
3945	>	}
3946	>
3947	>	/**
3948	>	* Returns the result of accumulating the given transformation
3949	>	* of all keys using the given reducer to combine values, and
3950	>	* the given basis as an identity value.
3951	>	*
3952	>	* @param parallelismThreshold the (estimated) number of elements
3953	>	* needed for this operation to be executed in parallel
3954	>	* @param transformer a function returning the transformation
3955	>	* for an element
3956	>	* @param basis the identity (initial default value) for the reduction
3957	>	* @param reducer a commutative associative combining function
3958	>	* @return the result of accumulating the given transformation
3959	>	* of all keys
3960	>	* @since 1.8
3961	>	*/
3962	>	public double reduceKeysToDouble(long parallelismThreshold,
3963	>	ToDoubleFunction<? super K> transformer,
3964	>	double basis,
3965	>	DoubleBinaryOperator reducer) {
3966	>	if (transformer == null || reducer == null)
3967	>	throw new NullPointerException();
3968	>	return new MapReduceKeysToDoubleTask<K,V>
3969	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3970	>	null, transformer, basis, reducer).invoke();
3971	>	}
3972	>
3973	>	/**
3974	>	* Returns the result of accumulating the given transformation
3975	>	* of all keys using the given reducer to combine values, and
3976	>	* the given basis as an identity value.
3977	>	*
3978	>	* @param parallelismThreshold the (estimated) number of elements
3979	>	* needed for this operation to be executed in parallel
3980	>	* @param transformer a function returning the transformation
3981	>	* for an element
3982	>	* @param basis the identity (initial default value) for the reduction
3983	>	* @param reducer a commutative associative combining function
3984	>	* @return the result of accumulating the given transformation
3985	>	* of all keys
3986	>	* @since 1.8
3987	>	*/
3988	>	public long reduceKeysToLong(long parallelismThreshold,
3989	>	ToLongFunction<? super K> transformer,
3990	>	long basis,
3991	>	LongBinaryOperator reducer) {
3992	>	if (transformer == null || reducer == null)
3993	>	throw new NullPointerException();
3994	>	return new MapReduceKeysToLongTask<K,V>
3995	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3996	>	null, transformer, basis, reducer).invoke();
3997	>	}
3998	>
3999	>	/**
4000	>	* Returns the result of accumulating the given transformation
4001	>	* of all keys using the given reducer to combine values, and
4002	>	* the given basis as an identity value.
4003	>	*
4004	>	* @param parallelismThreshold the (estimated) number of elements
4005	>	* needed for this operation to be executed in parallel
4006	>	* @param transformer a function returning the transformation
4007	>	* for an element
4008	>	* @param basis the identity (initial default value) for the reduction
4009	>	* @param reducer a commutative associative combining function
4010	>	* @return the result of accumulating the given transformation
4011	>	* of all keys
4012	>	* @since 1.8
4013	>	*/
4014	>	public int reduceKeysToInt(long parallelismThreshold,
4015	>	ToIntFunction<? super K> transformer,
4016	>	int basis,
4017	>	IntBinaryOperator reducer) {
4018	>	if (transformer == null || reducer == null)
4019	>	throw new NullPointerException();
4020	>	return new MapReduceKeysToIntTask<K,V>
4021	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4022	>	null, transformer, basis, reducer).invoke();
4023	>	}
4024	>
4025	>	/**
4026	>	* Performs the given action for each value.
4027	>	*
4028	>	* @param parallelismThreshold the (estimated) number of elements
4029	>	* needed for this operation to be executed in parallel
4030	>	* @param action the action
4031	>	* @since 1.8
4032	>	*/
4033	>	public void forEachValue(long parallelismThreshold,
4034	>	Consumer<? super V> action) {
4035	>	if (action == null)
4036	>	throw new NullPointerException();
4037	>	new ForEachValueTask<K,V>
4038	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4039	>	action).invoke();
4040	>	}
4041	>
4042	>	/**
4043	>	* Performs the given action for each non-null transformation
4044	>	* of each value.
4045	>	*
4046	>	* @param parallelismThreshold the (estimated) number of elements
4047	>	* needed for this operation to be executed in parallel
4048	>	* @param transformer a function returning the transformation
4049	>	* for an element, or null if there is no transformation (in
4050	>	* which case the action is not applied)
4051	>	* @param action the action
4052	>	* @param <U> the return type of the transformer
4053	>	* @since 1.8
4054	>	*/
4055	>	public <U> void forEachValue(long parallelismThreshold,
4056	>	Function<? super V, ? extends U> transformer,
4057	>	Consumer<? super U> action) {
4058	>	if (transformer == null || action == null)
4059	>	throw new NullPointerException();
4060	>	new ForEachTransformedValueTask<K,V,U>
4061	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4062	>	transformer, action).invoke();
4063	>	}
4064	>
4065	>	/**
4066	>	* Returns a non-null result from applying the given search
4067	>	* function on each value, or null if none.  Upon success,
4068	>	* further element processing is suppressed and the results of
4069	>	* any other parallel invocations of the search function are
4070	>	* ignored.
4071	>	*
4072	>	* @param parallelismThreshold the (estimated) number of elements
4073	>	* needed for this operation to be executed in parallel
4074	>	* @param searchFunction a function returning a non-null
4075	>	* result on success, else null
4076	>	* @param <U> the return type of the search function
4077	>	* @return a non-null result from applying the given search
4078	>	* function on each value, or null if none
4079	>	* @since 1.8
4080	>	*/
4081	>	public <U> U searchValues(long parallelismThreshold,
4082	>	Function<? super V, ? extends U> searchFunction) {
4083	>	if (searchFunction == null) throw new NullPointerException();
4084	>	return new SearchValuesTask<K,V,U>
4085	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4086	>	searchFunction, new AtomicReference<U>()).invoke();
4087	>	}
4088	>
4089	>	/**
4090	>	* Returns the result of accumulating all values using the
4091	>	* given reducer to combine values, or null if none.
4092	>	*
4093	>	* @param parallelismThreshold the (estimated) number of elements
4094	>	* needed for this operation to be executed in parallel
4095	>	* @param reducer a commutative associative combining function
4096	>	* @return the result of accumulating all values
4097	>	* @since 1.8
4098	>	*/
4099	>	public V reduceValues(long parallelismThreshold,
4100	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4101	>	if (reducer == null) throw new NullPointerException();
4102	>	return new ReduceValuesTask<K,V>
4103	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4104	>	null, reducer).invoke();
4105	>	}
4106	>
4107	>	/**
4108	>	* Returns the result of accumulating the given transformation
4109	>	* of all values using the given reducer to combine values, or
4110	>	* null if none.
4111	>	*
4112	>	* @param parallelismThreshold the (estimated) number of elements
4113	>	* needed for this operation to be executed in parallel
4114	>	* @param transformer a function returning the transformation
4115	>	* for an element, or null if there is no transformation (in
4116	>	* which case it is not combined)
4117	>	* @param reducer a commutative associative combining function
4118	>	* @param <U> the return type of the transformer
4119	>	* @return the result of accumulating the given transformation
4120	>	* of all values
4121	>	* @since 1.8
4122	>	*/
4123	>	public <U> U reduceValues(long parallelismThreshold,
4124	>	Function<? super V, ? extends U> transformer,
4125	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4126	>	if (transformer == null || reducer == null)
4127	>	throw new NullPointerException();
4128	>	return new MapReduceValuesTask<K,V,U>
4129	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4130	>	null, transformer, reducer).invoke();
4131	>	}
4132	>
4133	>	/**
4134	>	* Returns the result of accumulating the given transformation
4135	>	* of all values using the given reducer to combine values,
4136	>	* and the given basis as an identity value.
4137	>	*
4138	>	* @param parallelismThreshold the (estimated) number of elements
4139	>	* needed for this operation to be executed in parallel
4140	>	* @param transformer a function returning the transformation
4141	>	* for an element
4142	>	* @param basis the identity (initial default value) for the reduction
4143	>	* @param reducer a commutative associative combining function
4144	>	* @return the result of accumulating the given transformation
4145	>	* of all values
4146	>	* @since 1.8
4147	>	*/
4148	>	public double reduceValuesToDouble(long parallelismThreshold,
4149	>	ToDoubleFunction<? super V> transformer,
4150	>	double basis,
4151	>	DoubleBinaryOperator reducer) {
4152	>	if (transformer == null || reducer == null)
4153	>	throw new NullPointerException();
4154	>	return new MapReduceValuesToDoubleTask<K,V>
4155	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4156	>	null, transformer, basis, reducer).invoke();
4157	>	}
4158	>
4159	>	/**
4160	>	* Returns the result of accumulating the given transformation
4161	>	* of all values using the given reducer to combine values,
4162	>	* and the given basis as an identity value.
4163	>	*
4164	>	* @param parallelismThreshold the (estimated) number of elements
4165	>	* needed for this operation to be executed in parallel
4166	>	* @param transformer a function returning the transformation
4167	>	* for an element
4168	>	* @param basis the identity (initial default value) for the reduction
4169	>	* @param reducer a commutative associative combining function
4170	>	* @return the result of accumulating the given transformation
4171	>	* of all values
4172	>	* @since 1.8
4173	>	*/
4174	>	public long reduceValuesToLong(long parallelismThreshold,
4175	>	ToLongFunction<? super V> transformer,
4176	>	long basis,
4177	>	LongBinaryOperator reducer) {
4178	>	if (transformer == null || reducer == null)
4179	>	throw new NullPointerException();
4180	>	return new MapReduceValuesToLongTask<K,V>
4181	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4182	>	null, transformer, basis, reducer).invoke();
4183	>	}
4184	>
4185	>	/**
4186	>	* Returns the result of accumulating the given transformation
4187	>	* of all values using the given reducer to combine values,
4188	>	* and the given basis as an identity value.
4189	>	*
4190	>	* @param parallelismThreshold the (estimated) number of elements
4191	>	* needed for this operation to be executed in parallel
4192	>	* @param transformer a function returning the transformation
4193	>	* for an element
4194	>	* @param basis the identity (initial default value) for the reduction
4195	>	* @param reducer a commutative associative combining function
4196	>	* @return the result of accumulating the given transformation
4197	>	* of all values
4198	>	* @since 1.8
4199	>	*/
4200	>	public int reduceValuesToInt(long parallelismThreshold,
4201	>	ToIntFunction<? super V> transformer,
4202	>	int basis,
4203	>	IntBinaryOperator reducer) {
4204	>	if (transformer == null || reducer == null)
4205	>	throw new NullPointerException();
4206	>	return new MapReduceValuesToIntTask<K,V>
4207	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4208	>	null, transformer, basis, reducer).invoke();
4209	>	}
4210	>
4211	>	/**
4212	>	* Performs the given action for each entry.
4213	>	*
4214	>	* @param parallelismThreshold the (estimated) number of elements
4215	>	* needed for this operation to be executed in parallel
4216	>	* @param action the action
4217	>	* @since 1.8
4218	>	*/
4219	>	public void forEachEntry(long parallelismThreshold,
4220	>	Consumer<? super Map.Entry<K,V>> action) {
4221	>	if (action == null) throw new NullPointerException();
4222	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4223	>	action).invoke();
4224	>	}
4225	>
4226	>	/**
4227	>	* Performs the given action for each non-null transformation
4228	>	* of each entry.
4229	>	*
4230	>	* @param parallelismThreshold the (estimated) number of elements
4231	>	* needed for this operation to be executed in parallel
4232	>	* @param transformer a function returning the transformation
4233	>	* for an element, or null if there is no transformation (in
4234	>	* which case the action is not applied)
4235	>	* @param action the action
4236	>	* @param <U> the return type of the transformer
4237	>	* @since 1.8
4238	>	*/
4239	>	public <U> void forEachEntry(long parallelismThreshold,
4240	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4241	>	Consumer<? super U> action) {
4242	>	if (transformer == null || action == null)
4243	>	throw new NullPointerException();
4244	>	new ForEachTransformedEntryTask<K,V,U>
4245	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4246	>	transformer, action).invoke();
4247	>	}
4248	>
4249	>	/**
4250	>	* Returns a non-null result from applying the given search
4251	>	* function on each entry, or null if none.  Upon success,
4252	>	* further element processing is suppressed and the results of
4253	>	* any other parallel invocations of the search function are
4254	>	* ignored.
4255	>	*
4256	>	* @param parallelismThreshold the (estimated) number of elements
4257	>	* needed for this operation to be executed in parallel
4258	>	* @param searchFunction a function returning a non-null
4259	>	* result on success, else null
4260	>	* @param <U> the return type of the search function
4261	>	* @return a non-null result from applying the given search
4262	>	* function on each entry, or null if none
4263	>	* @since 1.8
4264	>	*/
4265	>	public <U> U searchEntries(long parallelismThreshold,
4266	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4267	>	if (searchFunction == null) throw new NullPointerException();
4268	>	return new SearchEntriesTask<K,V,U>
4269	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4270	>	searchFunction, new AtomicReference<U>()).invoke();
4271	>	}
4272	>
4273	>	/**
4274	>	* Returns the result of accumulating all entries using the
4275	>	* given reducer to combine values, or null if none.
4276	>	*
4277	>	* @param parallelismThreshold the (estimated) number of elements
4278	>	* needed for this operation to be executed in parallel
4279	>	* @param reducer a commutative associative combining function
4280	>	* @return the result of accumulating all entries
4281	>	* @since 1.8
4282	>	*/
4283	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4284	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4285	>	if (reducer == null) throw new NullPointerException();
4286	>	return new ReduceEntriesTask<K,V>
4287	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4288	>	null, reducer).invoke();
4289	>	}
4290	>
4291	>	/**
4292	>	* Returns the result of accumulating the given transformation
4293	>	* of all entries using the given reducer to combine values,
4294	>	* or null if none.
4295	>	*
4296	>	* @param parallelismThreshold the (estimated) number of elements
4297	>	* needed for this operation to be executed in parallel
4298	>	* @param transformer a function returning the transformation
4299	>	* for an element, or null if there is no transformation (in
4300	>	* which case it is not combined)
4301	>	* @param reducer a commutative associative combining function
4302	>	* @param <U> the return type of the transformer
4303	>	* @return the result of accumulating the given transformation
4304	>	* of all entries
4305	>	* @since 1.8
4306	>	*/
4307	>	public <U> U reduceEntries(long parallelismThreshold,
4308	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4309	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4310	>	if (transformer == null || reducer == null)
4311	>	throw new NullPointerException();
4312	>	return new MapReduceEntriesTask<K,V,U>
4313	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4314	>	null, transformer, reducer).invoke();
4315	>	}
4316	>
4317	>	/**
4318	>	* Returns the result of accumulating the given transformation
4319	>	* of all entries using the given reducer to combine values,
4320	>	* and the given basis as an identity value.
4321	>	*
4322	>	* @param parallelismThreshold the (estimated) number of elements
4323	>	* needed for this operation to be executed in parallel
4324	>	* @param transformer a function returning the transformation
4325	>	* for an element
4326	>	* @param basis the identity (initial default value) for the reduction
4327	>	* @param reducer a commutative associative combining function
4328	>	* @return the result of accumulating the given transformation
4329	>	* of all entries
4330	>	* @since 1.8
4331	>	*/
4332	>	public double reduceEntriesToDouble(long parallelismThreshold,
4333	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4334	>	double basis,
4335	>	DoubleBinaryOperator reducer) {
4336	>	if (transformer == null || reducer == null)
4337	>	throw new NullPointerException();
4338	>	return new MapReduceEntriesToDoubleTask<K,V>
4339	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4340	>	null, transformer, basis, reducer).invoke();
4341	>	}
4342	>
4343	>	/**
4344	>	* Returns the result of accumulating the given transformation
4345	>	* of all entries using the given reducer to combine values,
4346	>	* and the given basis as an identity value.
4347	>	*
4348	>	* @param parallelismThreshold the (estimated) number of elements
4349	>	* needed for this operation to be executed in parallel
4350	>	* @param transformer a function returning the transformation
4351	>	* for an element
4352	>	* @param basis the identity (initial default value) for the reduction
4353	>	* @param reducer a commutative associative combining function
4354	>	* @return the result of accumulating the given transformation
4355	>	* of all entries
4356	>	* @since 1.8
4357	>	*/
4358	>	public long reduceEntriesToLong(long parallelismThreshold,
4359	>	ToLongFunction<Map.Entry<K,V>> transformer,
4360	>	long basis,
4361	>	LongBinaryOperator reducer) {
4362	>	if (transformer == null || reducer == null)
4363	>	throw new NullPointerException();
4364	>	return new MapReduceEntriesToLongTask<K,V>
4365	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4366	>	null, transformer, basis, reducer).invoke();
4367	>	}
4368	>
4369	>	/**
4370	>	* Returns the result of accumulating the given transformation
4371	>	* of all entries using the given reducer to combine values,
4372	>	* and the given basis as an identity value.
4373	>	*
4374	>	* @param parallelismThreshold the (estimated) number of elements
4375	>	* needed for this operation to be executed in parallel
4376	>	* @param transformer a function returning the transformation
4377	>	* for an element
4378	>	* @param basis the identity (initial default value) for the reduction
4379	>	* @param reducer a commutative associative combining function
4380	>	* @return the result of accumulating the given transformation
4381	>	* of all entries
4382	>	* @since 1.8
4383	>	*/
4384	>	public int reduceEntriesToInt(long parallelismThreshold,
4385	>	ToIntFunction<Map.Entry<K,V>> transformer,
4386	>	int basis,
4387	>	IntBinaryOperator reducer) {
4388	>	if (transformer == null || reducer == null)
4389	>	throw new NullPointerException();
4390	>	return new MapReduceEntriesToIntTask<K,V>
4391	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4392	>	null, transformer, basis, reducer).invoke();
4393	>	}
4394	>
4395	>
4396	>	/* ----------------Views -------------- */
4397	>
4398	>	/**
4399	>	* Base class for views.
4400	>	*/
4401	>	abstract static class CollectionView<K,V,E>
4402	>	implements Collection<E>, java.io.Serializable {
4403	>	private static final long serialVersionUID = 7249069246763182397L;
4404	>	final ConcurrentHashMap<K,V> map;
4405	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4406	>
4407	>	/**
4408	>	* Returns the map backing this view.
4409	>	*
4410	>	* @return the map backing this view
4411	>	*/
4412	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4413	>
4414	>	/**
4415	>	* Removes all of the elements from this view, by removing all
4416	>	* the mappings from the map backing this view.
4417	>	*/
4418	>	public final void clear()      { map.clear(); }
4419	>	public final int size()        { return map.size(); }
4420	>	public final boolean isEmpty() { return map.isEmpty(); }
4421	>
4422	>	// implementations below rely on concrete classes supplying these
4423	>	// abstract methods
4424	>	/**
4425	>	* Returns an iterator over the elements in this collection.
4426	>	*
4427	>	* <p>The returned iterator is
4428	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4429	>	*
4430	>	* @return an iterator over the elements in this collection
4431	>	*/
4432	>	public abstract Iterator<E> iterator();
4433	>	public abstract boolean contains(Object o);
4434	>	public abstract boolean remove(Object o);
4435	>
4436	>	private static final String OOME_MSG = "Required array size too large";
4437	>
4438	>	public final Object[] toArray() {
4439	>	long sz = map.mappingCount();
4440	>	if (sz > MAX_ARRAY_SIZE)
4441	>	throw new OutOfMemoryError(OOME_MSG);
4442	>	int n = (int)sz;
4443	>	Object[] r = new Object[n];
4444	>	int i = 0;
4445	>	for (E e : this) {
4446	>	if (i == n) {
4447	>	if (n >= MAX_ARRAY_SIZE)
4448	>	throw new OutOfMemoryError(OOME_MSG);
4449	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4450	>	n = MAX_ARRAY_SIZE;
4451	>	else
4452	>	n += (n >>> 1) + 1;
4453	>	r = Arrays.copyOf(r, n);
4454	>	}
4455	>	r[i++] = e;
4456	>	}
4457	>	return (i == n) ? r : Arrays.copyOf(r, i);
4458	>	}
4459	>
4460	>	@SuppressWarnings("unchecked")
4461	>	public final <T> T[] toArray(T[] a) {
4462	>	long sz = map.mappingCount();
4463	>	if (sz > MAX_ARRAY_SIZE)
4464	>	throw new OutOfMemoryError(OOME_MSG);
4465	>	int m = (int)sz;
4466	>	T[] r = (a.length >= m) ? a :
4467	>	(T[])java.lang.reflect.Array
4468	>	.newInstance(a.getClass().getComponentType(), m);
4469	>	int n = r.length;
4470	>	int i = 0;
4471	>	for (E e : this) {
4472	>	if (i == n) {
4473	>	if (n >= MAX_ARRAY_SIZE)
4474	>	throw new OutOfMemoryError(OOME_MSG);
4475	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4476	>	n = MAX_ARRAY_SIZE;
4477	>	else
4478	>	n += (n >>> 1) + 1;
4479	>	r = Arrays.copyOf(r, n);
4480	>	}
4481	>	r[i++] = (T)e;
4482	>	}
4483	>	if (a == r && i < n) {
4484	>	r[i] = null; // null-terminate
4485	>	return r;
4486	>	}
4487	>	return (i == n) ? r : Arrays.copyOf(r, i);
4488		}
4489	<	public Object[] toArray() {
4490	<	Collection<K> c = new ArrayList<K>(size());
4491	<	for (K k : this)
4492	<	c.add(k);
4493	<	return c.toArray();
4489	>
4490	>	/**
4491	>	* Returns a string representation of this collection.
4492	>	* The string representation consists of the string representations
4493	>	* of the collection's elements in the order they are returned by
4494	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4495	>	* Adjacent elements are separated by the characters {@code ", "}
4496	>	* (comma and space).  Elements are converted to strings as by
4497	>	* {@link String#valueOf(Object)}.
4498	>	*
4499	>	* @return a string representation of this collection
4500	>	*/
4501	>	public final String toString() {
4502	>	StringBuilder sb = new StringBuilder();
4503	>	sb.append('[');
4504	>	Iterator<E> it = iterator();
4505	>	if (it.hasNext()) {
4506	>	for (;;) {
4507	>	Object e = it.next();
4508	>	sb.append(e == this ? "(this Collection)" : e);
4509	>	if (!it.hasNext())
4510	>	break;
4511	>	sb.append(',').append(' ');
4512	>	}
4513	>	}
4514	>	return sb.append(']').toString();
4515		}
4516	<	public <T> T[] toArray(T[] a) {
4517	<	Collection<K> c = new ArrayList<K>();
4518	<	for (K k : this)
4519	<	c.add(k);
4520	<	return c.toArray(a);
4516	>
4517	>	public final boolean containsAll(Collection<?> c) {
4518	>	if (c != this) {
4519	>	for (Object e : c) {
4520	>	if (e == null || !contains(e))
4521	>	return false;
4522	>	}
4523	>	}
4524	>	return true;
4525		}
1191	–	}
4526
4527	<	final class Values extends AbstractCollection<V> {
4528	<	public Iterator<V> iterator() {
4529	<	return new ValueIterator();
4527	>	public boolean removeAll(Collection<?> c) {
4528	>	if (c == null) throw new NullPointerException();
4529	>	boolean modified = false;
4530	>	// Use (c instanceof Set) as a hint that lookup in c is as
4531	>	// efficient as this view
4532	>	if (c instanceof Set<?> && c.size() > map.table.length) {
4533	>	for (Iterator<?> it = iterator(); it.hasNext(); ) {
4534	>	if (c.contains(it.next())) {
4535	>	it.remove();
4536	>	modified = true;
4537	>	}
4538	>	}
4539	>	} else {
4540	>	for (Object e : c)
4541	>	modified |= remove(e);
4542	>	}
4543	>	return modified;
4544		}
4545	<	public int size() {
4546	<	return ConcurrentHashMap.this.size();
4545	>
4546	>	public final boolean retainAll(Collection<?> c) {
4547	>	if (c == null) throw new NullPointerException();
4548	>	boolean modified = false;
4549	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4550	>	if (!c.contains(it.next())) {
4551	>	it.remove();
4552	>	modified = true;
4553	>	}
4554	>	}
4555	>	return modified;
4556		}
4557	<	public boolean contains(Object o) {
4558	<	return ConcurrentHashMap.this.containsValue(o);
4557	>
4558	>	}
4559	>
4560	>	/**
4561	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4562	>	* which additions may optionally be enabled by mapping to a
4563	>	* common value.  This class cannot be directly instantiated.
4564	>	* See {@link #keySet() keySet()},
4565	>	* {@link #keySet(Object) keySet(V)},
4566	>	* {@link #newKeySet() newKeySet()},
4567	>	* {@link #newKeySet(int) newKeySet(int)}.
4568	>	*
4569	>	* @since 1.8
4570	>	*/
4571	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4572	>	implements Set<K>, java.io.Serializable {
4573	>	private static final long serialVersionUID = 7249069246763182397L;
4574	>	private final V value;
4575	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4576	>	super(map);
4577	>	this.value = value;
4578		}
4579	<	public void clear() {
4580	<	ConcurrentHashMap.this.clear();
4579	>
4580	>	/**
4581	>	* Returns the default mapped value for additions,
4582	>	* or {@code null} if additions are not supported.
4583	>	*
4584	>	* @return the default mapped value for additions, or {@code null}
4585	>	* if not supported
4586	>	*/
4587	>	public V getMappedValue() { return value; }
4588	>
4589	>	/**
4590	>	* {@inheritDoc}
4591	>	* @throws NullPointerException if the specified key is null
4592	>	*/
4593	>	public boolean contains(Object o) { return map.containsKey(o); }
4594	>
4595	>	/**
4596	>	* Removes the key from this map view, by removing the key (and its
4597	>	* corresponding value) from the backing map.  This method does
4598	>	* nothing if the key is not in the map.
4599	>	*
4600	>	* @param  o the key to be removed from the backing map
4601	>	* @return {@code true} if the backing map contained the specified key
4602	>	* @throws NullPointerException if the specified key is null
4603	>	*/
4604	>	public boolean remove(Object o) { return map.remove(o) != null; }
4605	>
4606	>	/**
4607	>	* @return an iterator over the keys of the backing map
4608	>	*/
4609	>	public Iterator<K> iterator() {
4610	>	Node<K,V>[] t;
4611	>	ConcurrentHashMap<K,V> m = map;
4612	>	int f = (t = m.table) == null ? 0 : t.length;
4613	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4614	>	}
4615	>
4616	>	/**
4617	>	* Adds the specified key to this set view by mapping the key to
4618	>	* the default mapped value in the backing map, if defined.
4619	>	*
4620	>	* @param e key to be added
4621	>	* @return {@code true} if this set changed as a result of the call
4622	>	* @throws NullPointerException if the specified key is null
4623	>	* @throws UnsupportedOperationException if no default mapped value
4624	>	* for additions was provided
4625	>	*/
4626	>	public boolean add(K e) {
4627	>	V v;
4628	>	if ((v = value) == null)
4629	>	throw new UnsupportedOperationException();
4630	>	return map.putVal(e, v, true) == null;
4631		}
4632	<	public Object[] toArray() {
4633	<	Collection<V> c = new ArrayList<V>(size());
4634	<	for (V v : this)
4635	<	c.add(v);
4636	<	return c.toArray();
4632	>
4633	>	/**
4634	>	* Adds all of the elements in the specified collection to this set,
4635	>	* as if by calling {@link #add} on each one.
4636	>	*
4637	>	* @param c the elements to be inserted into this set
4638	>	* @return {@code true} if this set changed as a result of the call
4639	>	* @throws NullPointerException if the collection or any of its
4640	>	* elements are {@code null}
4641	>	* @throws UnsupportedOperationException if no default mapped value
4642	>	* for additions was provided
4643	>	*/
4644	>	public boolean addAll(Collection<? extends K> c) {
4645	>	boolean added = false;
4646	>	V v;
4647	>	if ((v = value) == null)
4648	>	throw new UnsupportedOperationException();
4649	>	for (K e : c) {
4650	>	if (map.putVal(e, v, true) == null)
4651	>	added = true;
4652	>	}
4653	>	return added;
4654		}
4655	<	public <T> T[] toArray(T[] a) {
4656	<	Collection<V> c = new ArrayList<V>(size());
4657	<	for (V v : this)
4658	<	c.add(v);
4659	<	return c.toArray(a);
4655	>
4656	>	public int hashCode() {
4657	>	int h = 0;
4658	>	for (K e : this)
4659	>	h += e.hashCode();
4660	>	return h;
4661	>	}
4662	>
4663	>	public boolean equals(Object o) {
4664	>	Set<?> c;
4665	>	return ((o instanceof Set) &&
4666	>	((c = (Set<?>)o) == this ||
4667	>	(containsAll(c) && c.containsAll(this))));
4668	>	}
4669	>
4670	>	public Spliterator<K> spliterator() {
4671	>	Node<K,V>[] t;
4672	>	ConcurrentHashMap<K,V> m = map;
4673	>	long n = m.sumCount();
4674	>	int f = (t = m.table) == null ? 0 : t.length;
4675	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4676	>	}
4677	>
4678	>	public void forEach(Consumer<? super K> action) {
4679	>	if (action == null) throw new NullPointerException();
4680	>	Node<K,V>[] t;
4681	>	if ((t = map.table) != null) {
4682	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4683	>	for (Node<K,V> p; (p = it.advance()) != null; )
4684	>	action.accept(p.key);
4685	>	}
4686		}
4687		}
4688
4689	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4690	<	public Iterator<Map.Entry<K,V>> iterator() {
4691	<	return new EntryIterator();
4689	>	/**
4690	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4691	>	* values, in which additions are disabled. This class cannot be
4692	>	* directly instantiated. See {@link #values()}.
4693	>	*/
4694	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4695	>	implements Collection<V>, java.io.Serializable {
4696	>	private static final long serialVersionUID = 2249069246763182397L;
4697	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4698	>	public final boolean contains(Object o) {
4699	>	return map.containsValue(o);
4700	>	}
4701	>
4702	>	public final boolean remove(Object o) {
4703	>	if (o != null) {
4704	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4705	>	if (o.equals(it.next())) {
4706	>	it.remove();
4707	>	return true;
4708	>	}
4709	>	}
4710	>	}
4711	>	return false;
4712	>	}
4713	>
4714	>	public final Iterator<V> iterator() {
4715	>	ConcurrentHashMap<K,V> m = map;
4716	>	Node<K,V>[] t;
4717	>	int f = (t = m.table) == null ? 0 : t.length;
4718	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4719	>	}
4720	>
4721	>	public final boolean add(V e) {
4722	>	throw new UnsupportedOperationException();
4723	>	}
4724	>	public final boolean addAll(Collection<? extends V> c) {
4725	>	throw new UnsupportedOperationException();
4726	>	}
4727	>
4728	>	@Override public boolean removeAll(Collection<?> c) {
4729	>	if (c == null) throw new NullPointerException();
4730	>	boolean modified = false;
4731	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4732	>	if (c.contains(it.next())) {
4733	>	it.remove();
4734	>	modified = true;
4735	>	}
4736	>	}
4737	>	return modified;
4738	>	}
4739	>
4740	>	public boolean removeIf(Predicate<? super V> filter) {
4741	>	return map.removeValueIf(filter);
4742	>	}
4743	>
4744	>	public Spliterator<V> spliterator() {
4745	>	Node<K,V>[] t;
4746	>	ConcurrentHashMap<K,V> m = map;
4747	>	long n = m.sumCount();
4748	>	int f = (t = m.table) == null ? 0 : t.length;
4749	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4750		}
4751	+
4752	+	public void forEach(Consumer<? super V> action) {
4753	+	if (action == null) throw new NullPointerException();
4754	+	Node<K,V>[] t;
4755	+	if ((t = map.table) != null) {
4756	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4757	+	for (Node<K,V> p; (p = it.advance()) != null; )
4758	+	action.accept(p.val);
4759	+	}
4760	+	}
4761	+	}
4762	+
4763	+	/**
4764	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4765	+	* entries.  This class cannot be directly instantiated. See
4766	+	* {@link #entrySet()}.
4767	+	*/
4768	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4769	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4770	+	private static final long serialVersionUID = 2249069246763182397L;
4771	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4772	+
4773		public boolean contains(Object o) {
4774	<	if (!(o instanceof Map.Entry))
4775	<	return false;
4776	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4777	<	V v = ConcurrentHashMap.this.get(e.getKey());
4778	<	return v != null && v.equals(e.getValue());
4774	>	Object k, v, r; Map.Entry<?,?> e;
4775	>	return ((o instanceof Map.Entry) &&
4776	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4777	>	(r = map.get(k)) != null &&
4778	>	(v = e.getValue()) != null &&
4779	>	(v == r || v.equals(r)));
4780		}
4781	+
4782		public boolean remove(Object o) {
4783	<	if (!(o instanceof Map.Entry))
4784	<	return false;
4785	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4786	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4783	>	Object k, v; Map.Entry<?,?> e;
4784	>	return ((o instanceof Map.Entry) &&
4785	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4786	>	(v = e.getValue()) != null &&
4787	>	map.remove(k, v));
4788	>	}
4789	>
4790	>	/**
4791	>	* @return an iterator over the entries of the backing map
4792	>	*/
4793	>	public Iterator<Map.Entry<K,V>> iterator() {
4794	>	ConcurrentHashMap<K,V> m = map;
4795	>	Node<K,V>[] t;
4796	>	int f = (t = m.table) == null ? 0 : t.length;
4797	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4798		}
4799	<	public int size() {
4800	<	return ConcurrentHashMap.this.size();
4799	>
4800	>	public boolean add(Entry<K,V> e) {
4801	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4802	>	}
4803	>
4804	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4805	>	boolean added = false;
4806	>	for (Entry<K,V> e : c) {
4807	>	if (add(e))
4808	>	added = true;
4809	>	}
4810	>	return added;
4811		}
4812	<	public void clear() {
4813	<	ConcurrentHashMap.this.clear();
4812	>
4813	>	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4814	>	return map.removeEntryIf(filter);
4815		}
4816	<	public Object[] toArray() {
4817	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
4818	<	for (Map.Entry<K,V> e : this)
4819	<	c.add(e);
4820	<	return c.toArray();
4816	>
4817	>	public final int hashCode() {
4818	>	int h = 0;
4819	>	Node<K,V>[] t;
4820	>	if ((t = map.table) != null) {
4821	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4822	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4823	>	h += p.hashCode();
4824	>	}
4825	>	}
4826	>	return h;
4827		}
4828	<	public <T> T[] toArray(T[] a) {
4829	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
4830	<	for (Map.Entry<K,V> e : this)
4831	<	c.add(e);
4832	<	return c.toArray(a);
4828	>
4829	>	public final boolean equals(Object o) {
4830	>	Set<?> c;
4831	>	return ((o instanceof Set) &&
4832	>	((c = (Set<?>)o) == this ||
4833	>	(containsAll(c) && c.containsAll(this))));
4834	>	}
4835	>
4836	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4837	>	Node<K,V>[] t;
4838	>	ConcurrentHashMap<K,V> m = map;
4839	>	long n = m.sumCount();
4840	>	int f = (t = m.table) == null ? 0 : t.length;
4841	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4842	>	}
4843	>
4844	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4845	>	if (action == null) throw new NullPointerException();
4846	>	Node<K,V>[] t;
4847	>	if ((t = map.table) != null) {
4848	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4849	>	for (Node<K,V> p; (p = it.advance()) != null; )
4850	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4851	>	}
4852		}
4853
4854		}
4855
4856	<	/* ---------------- Serialization Support -------------- */
4856	>	// -------------------------------------------------------
4857
4858		/**
4859	<	* Save the state of the <tt>ConcurrentHashMap</tt> instance to a
4860	<	* stream (i.e., serialize it).
1263	<	* @param s the stream
1264	<	* @serialData
1265	<	* the key (Object) and value (Object)
1266	<	* for each key-value mapping, followed by a null pair.
1267	<	* The key-value mappings are emitted in no particular order.
4859	>	* Base class for bulk tasks. Repeats some fields and code from
4860	>	* class Traverser, because we need to subclass CountedCompleter.
4861		*/
4862	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
4863	<	s.defaultWriteObject();
4862	>	@SuppressWarnings("serial")
4863	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4864	>	Node<K,V>[] tab;        // same as Traverser
4865	>	Node<K,V> next;
4866	>	TableStack<K,V> stack, spare;
4867	>	int index;
4868	>	int baseIndex;
4869	>	int baseLimit;
4870	>	final int baseSize;
4871	>	int batch;              // split control
4872	>
4873	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4874	>	super(par);
4875	>	this.batch = b;
4876	>	this.index = this.baseIndex = i;
4877	>	if ((this.tab = t) == null)
4878	>	this.baseSize = this.baseLimit = 0;
4879	>	else if (par == null)
4880	>	this.baseSize = this.baseLimit = t.length;
4881	>	else {
4882	>	this.baseLimit = f;
4883	>	this.baseSize = par.baseSize;
4884	>	}
4885	>	}
4886
4887	<	for (int k = 0; k < segments.length; ++k) {
4888	<	Segment<K,V> seg = segments[k];
4889	<	seg.lock();
4890	<	try {
4891	<	HashEntry<K,V>[] tab = seg.table;
4892	<	for (int i = 0; i < tab.length; ++i) {
4893	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
4894	<	s.writeObject(e.key);
4895	<	s.writeObject(e.value);
4887	>	/**
4888	>	* Same as Traverser version.
4889	>	*/
4890	>	final Node<K,V> advance() {
4891	>	Node<K,V> e;
4892	>	if ((e = next) != null)
4893	>	e = e.next;
4894	>	for (;;) {
4895	>	Node<K,V>[] t; int i, n;
4896	>	if (e != null)
4897	>	return next = e;
4898	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4899	>	(n = t.length) <= (i = index) || i < 0)
4900	>	return next = null;
4901	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4902	>	if (e instanceof ForwardingNode) {
4903	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4904	>	e = null;
4905	>	pushState(t, i, n);
4906	>	continue;
4907		}
4908	+	else if (e instanceof TreeBin)
4909	+	e = ((TreeBin<K,V>)e).first;
4910	+	else
4911	+	e = null;
4912		}
4913	<	} finally {
4914	<	seg.unlock();
4913	>	if (stack != null)
4914	>	recoverState(n);
4915	>	else if ((index = i + baseSize) >= n)
4916	>	index = ++baseIndex;
4917		}
4918		}
4919	<	s.writeObject(null);
4920	<	s.writeObject(null);
4919	>
4920	>	private void pushState(Node<K,V>[] t, int i, int n) {
4921	>	TableStack<K,V> s = spare;
4922	>	if (s != null)
4923	>	spare = s.next;
4924	>	else
4925	>	s = new TableStack<K,V>();
4926	>	s.tab = t;
4927	>	s.length = n;
4928	>	s.index = i;
4929	>	s.next = stack;
4930	>	stack = s;
4931	>	}
4932	>
4933	>	private void recoverState(int n) {
4934	>	TableStack<K,V> s; int len;
4935	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4936	>	n = len;
4937	>	index = s.index;
4938	>	tab = s.tab;
4939	>	s.tab = null;
4940	>	TableStack<K,V> next = s.next;
4941	>	s.next = spare; // save for reuse
4942	>	stack = next;
4943	>	spare = s;
4944	>	}
4945	>	if (s == null && (index += baseSize) >= n)
4946	>	index = ++baseIndex;
4947	>	}
4948		}
4949
4950	<	/**
4951	<	* Reconstitute the <tt>ConcurrentHashMap</tt> instance from a
4952	<	* stream (i.e., deserialize it).
4953	<	* @param s the stream
4954	<	*/
4955	<	private void readObject(java.io.ObjectInputStream s)
4956	<	throws IOException, ClassNotFoundException  {
4957	<	s.defaultReadObject();
4950	>	/*
4951	>	* Task classes. Coded in a regular but ugly format/style to
4952	>	* simplify checks that each variant differs in the right way from
4953	>	* others. The null screenings exist because compilers cannot tell
4954	>	* that we've already null-checked task arguments, so we force
4955	>	* simplest hoisted bypass to help avoid convoluted traps.
4956	>	*/
4957	>	@SuppressWarnings("serial")
4958	>	static final class ForEachKeyTask<K,V>
4959	>	extends BulkTask<K,V,Void> {
4960	>	final Consumer<? super K> action;
4961	>	ForEachKeyTask
4962	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4963	>	Consumer<? super K> action) {
4964	>	super(p, b, i, f, t);
4965	>	this.action = action;
4966	>	}
4967	>	public final void compute() {
4968	>	final Consumer<? super K> action;
4969	>	if ((action = this.action) != null) {
4970	>	for (int i = baseIndex, f, h; batch > 0 &&
4971	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4972	>	addToPendingCount(1);
4973	>	new ForEachKeyTask<K,V>
4974	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4975	>	action).fork();
4976	>	}
4977	>	for (Node<K,V> p; (p = advance()) != null;)
4978	>	action.accept(p.key);
4979	>	propagateCompletion();
4980	>	}
4981	>	}
4982	>	}
4983
4984	<	// Initialize each segment to be minimally sized, and let grow.
4985	<	for (int i = 0; i < segments.length; ++i) {
4986	<	segments[i].setTable(new HashEntry[1]);
4984	>	@SuppressWarnings("serial")
4985	>	static final class ForEachValueTask<K,V>
4986	>	extends BulkTask<K,V,Void> {
4987	>	final Consumer<? super V> action;
4988	>	ForEachValueTask
4989	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4990	>	Consumer<? super V> action) {
4991	>	super(p, b, i, f, t);
4992	>	this.action = action;
4993	>	}
4994	>	public final void compute() {
4995	>	final Consumer<? super V> action;
4996	>	if ((action = this.action) != null) {
4997	>	for (int i = baseIndex, f, h; batch > 0 &&
4998	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4999	>	addToPendingCount(1);
5000	>	new ForEachValueTask<K,V>
5001	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5002	>	action).fork();
5003	>	}
5004	>	for (Node<K,V> p; (p = advance()) != null;)
5005	>	action.accept(p.val);
5006	>	propagateCompletion();
5007	>	}
5008		}
5009	+	}
5010
5011	<	// Read the keys and values, and put the mappings in the table
5012	<	for (;;) {
5013	<	K key = (K) s.readObject();
5014	<	V value = (V) s.readObject();
5015	<	if (key == null)
5016	<	break;
5017	<	put(key, value);
5011	>	@SuppressWarnings("serial")
5012	>	static final class ForEachEntryTask<K,V>
5013	>	extends BulkTask<K,V,Void> {
5014	>	final Consumer<? super Entry<K,V>> action;
5015	>	ForEachEntryTask
5016	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5017	>	Consumer<? super Entry<K,V>> action) {
5018	>	super(p, b, i, f, t);
5019	>	this.action = action;
5020	>	}
5021	>	public final void compute() {
5022	>	final Consumer<? super Entry<K,V>> action;
5023	>	if ((action = this.action) != null) {
5024	>	for (int i = baseIndex, f, h; batch > 0 &&
5025	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5026	>	addToPendingCount(1);
5027	>	new ForEachEntryTask<K,V>
5028	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5029	>	action).fork();
5030	>	}
5031	>	for (Node<K,V> p; (p = advance()) != null; )
5032	>	action.accept(p);
5033	>	propagateCompletion();
5034	>	}
5035	>	}
5036	>	}
5037	>
5038	>	@SuppressWarnings("serial")
5039	>	static final class ForEachMappingTask<K,V>
5040	>	extends BulkTask<K,V,Void> {
5041	>	final BiConsumer<? super K, ? super V> action;
5042	>	ForEachMappingTask
5043	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5044	>	BiConsumer<? super K,? super V> action) {
5045	>	super(p, b, i, f, t);
5046	>	this.action = action;
5047	>	}
5048	>	public final void compute() {
5049	>	final BiConsumer<? super K, ? super V> action;
5050	>	if ((action = this.action) != null) {
5051	>	for (int i = baseIndex, f, h; batch > 0 &&
5052	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5053	>	addToPendingCount(1);
5054	>	new ForEachMappingTask<K,V>
5055	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5056	>	action).fork();
5057	>	}
5058	>	for (Node<K,V> p; (p = advance()) != null; )
5059	>	action.accept(p.key, p.val);
5060	>	propagateCompletion();
5061	>	}
5062	>	}
5063	>	}
5064	>
5065	>	@SuppressWarnings("serial")
5066	>	static final class ForEachTransformedKeyTask<K,V,U>
5067	>	extends BulkTask<K,V,Void> {
5068	>	final Function<? super K, ? extends U> transformer;
5069	>	final Consumer<? super U> action;
5070	>	ForEachTransformedKeyTask
5071	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5072	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5073	>	super(p, b, i, f, t);
5074	>	this.transformer = transformer; this.action = action;
5075	>	}
5076	>	public final void compute() {
5077	>	final Function<? super K, ? extends U> transformer;
5078	>	final Consumer<? super U> action;
5079	>	if ((transformer = this.transformer) != null &&
5080	>	(action = this.action) != null) {
5081	>	for (int i = baseIndex, f, h; batch > 0 &&
5082	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5083	>	addToPendingCount(1);
5084	>	new ForEachTransformedKeyTask<K,V,U>
5085	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5086	>	transformer, action).fork();
5087	>	}
5088	>	for (Node<K,V> p; (p = advance()) != null; ) {
5089	>	U u;
5090	>	if ((u = transformer.apply(p.key)) != null)
5091	>	action.accept(u);
5092	>	}
5093	>	propagateCompletion();
5094	>	}
5095	>	}
5096	>	}
5097	>
5098	>	@SuppressWarnings("serial")
5099	>	static final class ForEachTransformedValueTask<K,V,U>
5100	>	extends BulkTask<K,V,Void> {
5101	>	final Function<? super V, ? extends U> transformer;
5102	>	final Consumer<? super U> action;
5103	>	ForEachTransformedValueTask
5104	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5105	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5106	>	super(p, b, i, f, t);
5107	>	this.transformer = transformer; this.action = action;
5108	>	}
5109	>	public final void compute() {
5110	>	final Function<? super V, ? extends U> transformer;
5111	>	final Consumer<? super U> action;
5112	>	if ((transformer = this.transformer) != null &&
5113	>	(action = this.action) != null) {
5114	>	for (int i = baseIndex, f, h; batch > 0 &&
5115	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5116	>	addToPendingCount(1);
5117	>	new ForEachTransformedValueTask<K,V,U>
5118	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5119	>	transformer, action).fork();
5120	>	}
5121	>	for (Node<K,V> p; (p = advance()) != null; ) {
5122	>	U u;
5123	>	if ((u = transformer.apply(p.val)) != null)
5124	>	action.accept(u);
5125	>	}
5126	>	propagateCompletion();
5127	>	}
5128	>	}
5129	>	}
5130	>
5131	>	@SuppressWarnings("serial")
5132	>	static final class ForEachTransformedEntryTask<K,V,U>
5133	>	extends BulkTask<K,V,Void> {
5134	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5135	>	final Consumer<? super U> action;
5136	>	ForEachTransformedEntryTask
5137	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5138	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5139	>	super(p, b, i, f, t);
5140	>	this.transformer = transformer; this.action = action;
5141	>	}
5142	>	public final void compute() {
5143	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5144	>	final Consumer<? super U> action;
5145	>	if ((transformer = this.transformer) != null &&
5146	>	(action = this.action) != null) {
5147	>	for (int i = baseIndex, f, h; batch > 0 &&
5148	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5149	>	addToPendingCount(1);
5150	>	new ForEachTransformedEntryTask<K,V,U>
5151	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5152	>	transformer, action).fork();
5153	>	}
5154	>	for (Node<K,V> p; (p = advance()) != null; ) {
5155	>	U u;
5156	>	if ((u = transformer.apply(p)) != null)
5157	>	action.accept(u);
5158	>	}
5159	>	propagateCompletion();
5160	>	}
5161	>	}
5162	>	}
5163	>
5164	>	@SuppressWarnings("serial")
5165	>	static final class ForEachTransformedMappingTask<K,V,U>
5166	>	extends BulkTask<K,V,Void> {
5167	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5168	>	final Consumer<? super U> action;
5169	>	ForEachTransformedMappingTask
5170	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5171	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5172	>	Consumer<? super U> action) {
5173	>	super(p, b, i, f, t);
5174	>	this.transformer = transformer; this.action = action;
5175	>	}
5176	>	public final void compute() {
5177	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5178	>	final Consumer<? super U> action;
5179	>	if ((transformer = this.transformer) != null &&
5180	>	(action = this.action) != null) {
5181	>	for (int i = baseIndex, f, h; batch > 0 &&
5182	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5183	>	addToPendingCount(1);
5184	>	new ForEachTransformedMappingTask<K,V,U>
5185	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5186	>	transformer, action).fork();
5187	>	}
5188	>	for (Node<K,V> p; (p = advance()) != null; ) {
5189	>	U u;
5190	>	if ((u = transformer.apply(p.key, p.val)) != null)
5191	>	action.accept(u);
5192	>	}
5193	>	propagateCompletion();
5194	>	}
5195	>	}
5196	>	}
5197	>
5198	>	@SuppressWarnings("serial")
5199	>	static final class SearchKeysTask<K,V,U>
5200	>	extends BulkTask<K,V,U> {
5201	>	final Function<? super K, ? extends U> searchFunction;
5202	>	final AtomicReference<U> result;
5203	>	SearchKeysTask
5204	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5205	>	Function<? super K, ? extends U> searchFunction,
5206	>	AtomicReference<U> result) {
5207	>	super(p, b, i, f, t);
5208	>	this.searchFunction = searchFunction; this.result = result;
5209	>	}
5210	>	public final U getRawResult() { return result.get(); }
5211	>	public final void compute() {
5212	>	final Function<? super K, ? extends U> searchFunction;
5213	>	final AtomicReference<U> result;
5214	>	if ((searchFunction = this.searchFunction) != null &&
5215	>	(result = this.result) != null) {
5216	>	for (int i = baseIndex, f, h; batch > 0 &&
5217	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5218	>	if (result.get() != null)
5219	>	return;
5220	>	addToPendingCount(1);
5221	>	new SearchKeysTask<K,V,U>
5222	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5223	>	searchFunction, result).fork();
5224	>	}
5225	>	while (result.get() == null) {
5226	>	U u;
5227	>	Node<K,V> p;
5228	>	if ((p = advance()) == null) {
5229	>	propagateCompletion();
5230	>	break;
5231	>	}
5232	>	if ((u = searchFunction.apply(p.key)) != null) {
5233	>	if (result.compareAndSet(null, u))
5234	>	quietlyCompleteRoot();
5235	>	break;
5236	>	}
5237	>	}
5238	>	}
5239	>	}
5240	>	}
5241	>
5242	>	@SuppressWarnings("serial")
5243	>	static final class SearchValuesTask<K,V,U>
5244	>	extends BulkTask<K,V,U> {
5245	>	final Function<? super V, ? extends U> searchFunction;
5246	>	final AtomicReference<U> result;
5247	>	SearchValuesTask
5248	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5249	>	Function<? super V, ? extends U> searchFunction,
5250	>	AtomicReference<U> result) {
5251	>	super(p, b, i, f, t);
5252	>	this.searchFunction = searchFunction; this.result = result;
5253	>	}
5254	>	public final U getRawResult() { return result.get(); }
5255	>	public final void compute() {
5256	>	final Function<? super V, ? extends U> searchFunction;
5257	>	final AtomicReference<U> result;
5258	>	if ((searchFunction = this.searchFunction) != null &&
5259	>	(result = this.result) != null) {
5260	>	for (int i = baseIndex, f, h; batch > 0 &&
5261	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5262	>	if (result.get() != null)
5263	>	return;
5264	>	addToPendingCount(1);
5265	>	new SearchValuesTask<K,V,U>
5266	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5267	>	searchFunction, result).fork();
5268	>	}
5269	>	while (result.get() == null) {
5270	>	U u;
5271	>	Node<K,V> p;
5272	>	if ((p = advance()) == null) {
5273	>	propagateCompletion();
5274	>	break;
5275	>	}
5276	>	if ((u = searchFunction.apply(p.val)) != null) {
5277	>	if (result.compareAndSet(null, u))
5278	>	quietlyCompleteRoot();
5279	>	break;
5280	>	}
5281	>	}
5282	>	}
5283	>	}
5284	>	}
5285	>
5286	>	@SuppressWarnings("serial")
5287	>	static final class SearchEntriesTask<K,V,U>
5288	>	extends BulkTask<K,V,U> {
5289	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5290	>	final AtomicReference<U> result;
5291	>	SearchEntriesTask
5292	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5293	>	Function<Entry<K,V>, ? extends U> searchFunction,
5294	>	AtomicReference<U> result) {
5295	>	super(p, b, i, f, t);
5296	>	this.searchFunction = searchFunction; this.result = result;
5297	>	}
5298	>	public final U getRawResult() { return result.get(); }
5299	>	public final void compute() {
5300	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5301	>	final AtomicReference<U> result;
5302	>	if ((searchFunction = this.searchFunction) != null &&
5303	>	(result = this.result) != null) {
5304	>	for (int i = baseIndex, f, h; batch > 0 &&
5305	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5306	>	if (result.get() != null)
5307	>	return;
5308	>	addToPendingCount(1);
5309	>	new SearchEntriesTask<K,V,U>
5310	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5311	>	searchFunction, result).fork();
5312	>	}
5313	>	while (result.get() == null) {
5314	>	U u;
5315	>	Node<K,V> p;
5316	>	if ((p = advance()) == null) {
5317	>	propagateCompletion();
5318	>	break;
5319	>	}
5320	>	if ((u = searchFunction.apply(p)) != null) {
5321	>	if (result.compareAndSet(null, u))
5322	>	quietlyCompleteRoot();
5323	>	return;
5324	>	}
5325	>	}
5326	>	}
5327	>	}
5328	>	}
5329	>
5330	>	@SuppressWarnings("serial")
5331	>	static final class SearchMappingsTask<K,V,U>
5332	>	extends BulkTask<K,V,U> {
5333	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5334	>	final AtomicReference<U> result;
5335	>	SearchMappingsTask
5336	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5337	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5338	>	AtomicReference<U> result) {
5339	>	super(p, b, i, f, t);
5340	>	this.searchFunction = searchFunction; this.result = result;
5341	>	}
5342	>	public final U getRawResult() { return result.get(); }
5343	>	public final void compute() {
5344	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5345	>	final AtomicReference<U> result;
5346	>	if ((searchFunction = this.searchFunction) != null &&
5347	>	(result = this.result) != null) {
5348	>	for (int i = baseIndex, f, h; batch > 0 &&
5349	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5350	>	if (result.get() != null)
5351	>	return;
5352	>	addToPendingCount(1);
5353	>	new SearchMappingsTask<K,V,U>
5354	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5355	>	searchFunction, result).fork();
5356	>	}
5357	>	while (result.get() == null) {
5358	>	U u;
5359	>	Node<K,V> p;
5360	>	if ((p = advance()) == null) {
5361	>	propagateCompletion();
5362	>	break;
5363	>	}
5364	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5365	>	if (result.compareAndSet(null, u))
5366	>	quietlyCompleteRoot();
5367	>	break;
5368	>	}
5369	>	}
5370	>	}
5371	>	}
5372	>	}
5373	>
5374	>	@SuppressWarnings("serial")
5375	>	static final class ReduceKeysTask<K,V>
5376	>	extends BulkTask<K,V,K> {
5377	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5378	>	K result;
5379	>	ReduceKeysTask<K,V> rights, nextRight;
5380	>	ReduceKeysTask
5381	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5382	>	ReduceKeysTask<K,V> nextRight,
5383	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5384	>	super(p, b, i, f, t); this.nextRight = nextRight;
5385	>	this.reducer = reducer;
5386	>	}
5387	>	public final K getRawResult() { return result; }
5388	>	public final void compute() {
5389	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5390	>	if ((reducer = this.reducer) != null) {
5391	>	for (int i = baseIndex, f, h; batch > 0 &&
5392	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5393	>	addToPendingCount(1);
5394	>	(rights = new ReduceKeysTask<K,V>
5395	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5396	>	rights, reducer)).fork();
5397	>	}
5398	>	K r = null;
5399	>	for (Node<K,V> p; (p = advance()) != null; ) {
5400	>	K u = p.key;
5401	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5402	>	}
5403	>	result = r;
5404	>	CountedCompleter<?> c;
5405	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5406	>	@SuppressWarnings("unchecked")
5407	>	ReduceKeysTask<K,V>
5408	>	t = (ReduceKeysTask<K,V>)c,
5409	>	s = t.rights;
5410	>	while (s != null) {
5411	>	K tr, sr;
5412	>	if ((sr = s.result) != null)
5413	>	t.result = (((tr = t.result) == null) ? sr :
5414	>	reducer.apply(tr, sr));
5415	>	s = t.rights = s.nextRight;
5416	>	}
5417	>	}
5418	>	}
5419	>	}
5420	>	}
5421	>
5422	>	@SuppressWarnings("serial")
5423	>	static final class ReduceValuesTask<K,V>
5424	>	extends BulkTask<K,V,V> {
5425	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5426	>	V result;
5427	>	ReduceValuesTask<K,V> rights, nextRight;
5428	>	ReduceValuesTask
5429	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5430	>	ReduceValuesTask<K,V> nextRight,
5431	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5432	>	super(p, b, i, f, t); this.nextRight = nextRight;
5433	>	this.reducer = reducer;
5434	>	}
5435	>	public final V getRawResult() { return result; }
5436	>	public final void compute() {
5437	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5438	>	if ((reducer = this.reducer) != null) {
5439	>	for (int i = baseIndex, f, h; batch > 0 &&
5440	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5441	>	addToPendingCount(1);
5442	>	(rights = new ReduceValuesTask<K,V>
5443	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5444	>	rights, reducer)).fork();
5445	>	}
5446	>	V r = null;
5447	>	for (Node<K,V> p; (p = advance()) != null; ) {
5448	>	V v = p.val;
5449	>	r = (r == null) ? v : reducer.apply(r, v);
5450	>	}
5451	>	result = r;
5452	>	CountedCompleter<?> c;
5453	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5454	>	@SuppressWarnings("unchecked")
5455	>	ReduceValuesTask<K,V>
5456	>	t = (ReduceValuesTask<K,V>)c,
5457	>	s = t.rights;
5458	>	while (s != null) {
5459	>	V tr, sr;
5460	>	if ((sr = s.result) != null)
5461	>	t.result = (((tr = t.result) == null) ? sr :
5462	>	reducer.apply(tr, sr));
5463	>	s = t.rights = s.nextRight;
5464	>	}
5465	>	}
5466	>	}
5467	>	}
5468	>	}
5469	>
5470	>	@SuppressWarnings("serial")
5471	>	static final class ReduceEntriesTask<K,V>
5472	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5473	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5474	>	Map.Entry<K,V> result;
5475	>	ReduceEntriesTask<K,V> rights, nextRight;
5476	>	ReduceEntriesTask
5477	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5478	>	ReduceEntriesTask<K,V> nextRight,
5479	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5480	>	super(p, b, i, f, t); this.nextRight = nextRight;
5481	>	this.reducer = reducer;
5482	>	}
5483	>	public final Map.Entry<K,V> getRawResult() { return result; }
5484	>	public final void compute() {
5485	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5486	>	if ((reducer = this.reducer) != null) {
5487	>	for (int i = baseIndex, f, h; batch > 0 &&
5488	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5489	>	addToPendingCount(1);
5490	>	(rights = new ReduceEntriesTask<K,V>
5491	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5492	>	rights, reducer)).fork();
5493	>	}
5494	>	Map.Entry<K,V> r = null;
5495	>	for (Node<K,V> p; (p = advance()) != null; )
5496	>	r = (r == null) ? p : reducer.apply(r, p);
5497	>	result = r;
5498	>	CountedCompleter<?> c;
5499	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5500	>	@SuppressWarnings("unchecked")
5501	>	ReduceEntriesTask<K,V>
5502	>	t = (ReduceEntriesTask<K,V>)c,
5503	>	s = t.rights;
5504	>	while (s != null) {
5505	>	Map.Entry<K,V> tr, sr;
5506	>	if ((sr = s.result) != null)
5507	>	t.result = (((tr = t.result) == null) ? sr :
5508	>	reducer.apply(tr, sr));
5509	>	s = t.rights = s.nextRight;
5510	>	}
5511	>	}
5512	>	}
5513	>	}
5514	>	}
5515	>
5516	>	@SuppressWarnings("serial")
5517	>	static final class MapReduceKeysTask<K,V,U>
5518	>	extends BulkTask<K,V,U> {
5519	>	final Function<? super K, ? extends U> transformer;
5520	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5521	>	U result;
5522	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5523	>	MapReduceKeysTask
5524	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5525	>	MapReduceKeysTask<K,V,U> nextRight,
5526	>	Function<? super K, ? extends U> transformer,
5527	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5528	>	super(p, b, i, f, t); this.nextRight = nextRight;
5529	>	this.transformer = transformer;
5530	>	this.reducer = reducer;
5531	>	}
5532	>	public final U getRawResult() { return result; }
5533	>	public final void compute() {
5534	>	final Function<? super K, ? extends U> transformer;
5535	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5536	>	if ((transformer = this.transformer) != null &&
5537	>	(reducer = this.reducer) != null) {
5538	>	for (int i = baseIndex, f, h; batch > 0 &&
5539	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5540	>	addToPendingCount(1);
5541	>	(rights = new MapReduceKeysTask<K,V,U>
5542	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5543	>	rights, transformer, reducer)).fork();
5544	>	}
5545	>	U r = null;
5546	>	for (Node<K,V> p; (p = advance()) != null; ) {
5547	>	U u;
5548	>	if ((u = transformer.apply(p.key)) != null)
5549	>	r = (r == null) ? u : reducer.apply(r, u);
5550	>	}
5551	>	result = r;
5552	>	CountedCompleter<?> c;
5553	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5554	>	@SuppressWarnings("unchecked")
5555	>	MapReduceKeysTask<K,V,U>
5556	>	t = (MapReduceKeysTask<K,V,U>)c,
5557	>	s = t.rights;
5558	>	while (s != null) {
5559	>	U tr, sr;
5560	>	if ((sr = s.result) != null)
5561	>	t.result = (((tr = t.result) == null) ? sr :
5562	>	reducer.apply(tr, sr));
5563	>	s = t.rights = s.nextRight;
5564	>	}
5565	>	}
5566	>	}
5567	>	}
5568	>	}
5569	>
5570	>	@SuppressWarnings("serial")
5571	>	static final class MapReduceValuesTask<K,V,U>
5572	>	extends BulkTask<K,V,U> {
5573	>	final Function<? super V, ? extends U> transformer;
5574	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5575	>	U result;
5576	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5577	>	MapReduceValuesTask
5578	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5579	>	MapReduceValuesTask<K,V,U> nextRight,
5580	>	Function<? super V, ? extends U> transformer,
5581	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5582	>	super(p, b, i, f, t); this.nextRight = nextRight;
5583	>	this.transformer = transformer;
5584	>	this.reducer = reducer;
5585	>	}
5586	>	public final U getRawResult() { return result; }
5587	>	public final void compute() {
5588	>	final Function<? super V, ? extends U> transformer;
5589	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5590	>	if ((transformer = this.transformer) != null &&
5591	>	(reducer = this.reducer) != null) {
5592	>	for (int i = baseIndex, f, h; batch > 0 &&
5593	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5594	>	addToPendingCount(1);
5595	>	(rights = new MapReduceValuesTask<K,V,U>
5596	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5597	>	rights, transformer, reducer)).fork();
5598	>	}
5599	>	U r = null;
5600	>	for (Node<K,V> p; (p = advance()) != null; ) {
5601	>	U u;
5602	>	if ((u = transformer.apply(p.val)) != null)
5603	>	r = (r == null) ? u : reducer.apply(r, u);
5604	>	}
5605	>	result = r;
5606	>	CountedCompleter<?> c;
5607	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5608	>	@SuppressWarnings("unchecked")
5609	>	MapReduceValuesTask<K,V,U>
5610	>	t = (MapReduceValuesTask<K,V,U>)c,
5611	>	s = t.rights;
5612	>	while (s != null) {
5613	>	U tr, sr;
5614	>	if ((sr = s.result) != null)
5615	>	t.result = (((tr = t.result) == null) ? sr :
5616	>	reducer.apply(tr, sr));
5617	>	s = t.rights = s.nextRight;
5618	>	}
5619	>	}
5620	>	}
5621	>	}
5622	>	}
5623	>
5624	>	@SuppressWarnings("serial")
5625	>	static final class MapReduceEntriesTask<K,V,U>
5626	>	extends BulkTask<K,V,U> {
5627	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5628	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5629	>	U result;
5630	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5631	>	MapReduceEntriesTask
5632	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5633	>	MapReduceEntriesTask<K,V,U> nextRight,
5634	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5635	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5636	>	super(p, b, i, f, t); this.nextRight = nextRight;
5637	>	this.transformer = transformer;
5638	>	this.reducer = reducer;
5639	>	}
5640	>	public final U getRawResult() { return result; }
5641	>	public final void compute() {
5642	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5643	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5644	>	if ((transformer = this.transformer) != null &&
5645	>	(reducer = this.reducer) != null) {
5646	>	for (int i = baseIndex, f, h; batch > 0 &&
5647	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5648	>	addToPendingCount(1);
5649	>	(rights = new MapReduceEntriesTask<K,V,U>
5650	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5651	>	rights, transformer, reducer)).fork();
5652	>	}
5653	>	U r = null;
5654	>	for (Node<K,V> p; (p = advance()) != null; ) {
5655	>	U u;
5656	>	if ((u = transformer.apply(p)) != null)
5657	>	r = (r == null) ? u : reducer.apply(r, u);
5658	>	}
5659	>	result = r;
5660	>	CountedCompleter<?> c;
5661	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5662	>	@SuppressWarnings("unchecked")
5663	>	MapReduceEntriesTask<K,V,U>
5664	>	t = (MapReduceEntriesTask<K,V,U>)c,
5665	>	s = t.rights;
5666	>	while (s != null) {
5667	>	U tr, sr;
5668	>	if ((sr = s.result) != null)
5669	>	t.result = (((tr = t.result) == null) ? sr :
5670	>	reducer.apply(tr, sr));
5671	>	s = t.rights = s.nextRight;
5672	>	}
5673	>	}
5674	>	}
5675	>	}
5676	>	}
5677	>
5678	>	@SuppressWarnings("serial")
5679	>	static final class MapReduceMappingsTask<K,V,U>
5680	>	extends BulkTask<K,V,U> {
5681	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5682	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5683	>	U result;
5684	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5685	>	MapReduceMappingsTask
5686	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5687	>	MapReduceMappingsTask<K,V,U> nextRight,
5688	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5689	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5690	>	super(p, b, i, f, t); this.nextRight = nextRight;
5691	>	this.transformer = transformer;
5692	>	this.reducer = reducer;
5693	>	}
5694	>	public final U getRawResult() { return result; }
5695	>	public final void compute() {
5696	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5697	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5698	>	if ((transformer = this.transformer) != null &&
5699	>	(reducer = this.reducer) != null) {
5700	>	for (int i = baseIndex, f, h; batch > 0 &&
5701	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5702	>	addToPendingCount(1);
5703	>	(rights = new MapReduceMappingsTask<K,V,U>
5704	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5705	>	rights, transformer, reducer)).fork();
5706	>	}
5707	>	U r = null;
5708	>	for (Node<K,V> p; (p = advance()) != null; ) {
5709	>	U u;
5710	>	if ((u = transformer.apply(p.key, p.val)) != null)
5711	>	r = (r == null) ? u : reducer.apply(r, u);
5712	>	}
5713	>	result = r;
5714	>	CountedCompleter<?> c;
5715	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5716	>	@SuppressWarnings("unchecked")
5717	>	MapReduceMappingsTask<K,V,U>
5718	>	t = (MapReduceMappingsTask<K,V,U>)c,
5719	>	s = t.rights;
5720	>	while (s != null) {
5721	>	U tr, sr;
5722	>	if ((sr = s.result) != null)
5723	>	t.result = (((tr = t.result) == null) ? sr :
5724	>	reducer.apply(tr, sr));
5725	>	s = t.rights = s.nextRight;
5726	>	}
5727	>	}
5728	>	}
5729	>	}
5730	>	}
5731	>
5732	>	@SuppressWarnings("serial")
5733	>	static final class MapReduceKeysToDoubleTask<K,V>
5734	>	extends BulkTask<K,V,Double> {
5735	>	final ToDoubleFunction<? super K> transformer;
5736	>	final DoubleBinaryOperator reducer;
5737	>	final double basis;
5738	>	double result;
5739	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5740	>	MapReduceKeysToDoubleTask
5741	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5742	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5743	>	ToDoubleFunction<? super K> transformer,
5744	>	double basis,
5745	>	DoubleBinaryOperator reducer) {
5746	>	super(p, b, i, f, t); this.nextRight = nextRight;
5747	>	this.transformer = transformer;
5748	>	this.basis = basis; this.reducer = reducer;
5749	>	}
5750	>	public final Double getRawResult() { return result; }
5751	>	public final void compute() {
5752	>	final ToDoubleFunction<? super K> transformer;
5753	>	final DoubleBinaryOperator reducer;
5754	>	if ((transformer = this.transformer) != null &&
5755	>	(reducer = this.reducer) != null) {
5756	>	double r = this.basis;
5757	>	for (int i = baseIndex, f, h; batch > 0 &&
5758	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5759	>	addToPendingCount(1);
5760	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5761	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5762	>	rights, transformer, r, reducer)).fork();
5763	>	}
5764	>	for (Node<K,V> p; (p = advance()) != null; )
5765	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5766	>	result = r;
5767	>	CountedCompleter<?> c;
5768	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5769	>	@SuppressWarnings("unchecked")
5770	>	MapReduceKeysToDoubleTask<K,V>
5771	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5772	>	s = t.rights;
5773	>	while (s != null) {
5774	>	t.result = reducer.applyAsDouble(t.result, s.result);
5775	>	s = t.rights = s.nextRight;
5776	>	}
5777	>	}
5778	>	}
5779	>	}
5780	>	}
5781	>
5782	>	@SuppressWarnings("serial")
5783	>	static final class MapReduceValuesToDoubleTask<K,V>
5784	>	extends BulkTask<K,V,Double> {
5785	>	final ToDoubleFunction<? super V> transformer;
5786	>	final DoubleBinaryOperator reducer;
5787	>	final double basis;
5788	>	double result;
5789	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5790	>	MapReduceValuesToDoubleTask
5791	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5792	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5793	>	ToDoubleFunction<? super V> transformer,
5794	>	double basis,
5795	>	DoubleBinaryOperator reducer) {
5796	>	super(p, b, i, f, t); this.nextRight = nextRight;
5797	>	this.transformer = transformer;
5798	>	this.basis = basis; this.reducer = reducer;
5799	>	}
5800	>	public final Double getRawResult() { return result; }
5801	>	public final void compute() {
5802	>	final ToDoubleFunction<? super V> transformer;
5803	>	final DoubleBinaryOperator reducer;
5804	>	if ((transformer = this.transformer) != null &&
5805	>	(reducer = this.reducer) != null) {
5806	>	double r = this.basis;
5807	>	for (int i = baseIndex, f, h; batch > 0 &&
5808	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5809	>	addToPendingCount(1);
5810	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5811	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5812	>	rights, transformer, r, reducer)).fork();
5813	>	}
5814	>	for (Node<K,V> p; (p = advance()) != null; )
5815	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5816	>	result = r;
5817	>	CountedCompleter<?> c;
5818	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5819	>	@SuppressWarnings("unchecked")
5820	>	MapReduceValuesToDoubleTask<K,V>
5821	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5822	>	s = t.rights;
5823	>	while (s != null) {
5824	>	t.result = reducer.applyAsDouble(t.result, s.result);
5825	>	s = t.rights = s.nextRight;
5826	>	}
5827	>	}
5828	>	}
5829	>	}
5830	>	}
5831	>
5832	>	@SuppressWarnings("serial")
5833	>	static final class MapReduceEntriesToDoubleTask<K,V>
5834	>	extends BulkTask<K,V,Double> {
5835	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5836	>	final DoubleBinaryOperator reducer;
5837	>	final double basis;
5838	>	double result;
5839	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5840	>	MapReduceEntriesToDoubleTask
5841	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5842	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5843	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5844	>	double basis,
5845	>	DoubleBinaryOperator reducer) {
5846	>	super(p, b, i, f, t); this.nextRight = nextRight;
5847	>	this.transformer = transformer;
5848	>	this.basis = basis; this.reducer = reducer;
5849	>	}
5850	>	public final Double getRawResult() { return result; }
5851	>	public final void compute() {
5852	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5853	>	final DoubleBinaryOperator reducer;
5854	>	if ((transformer = this.transformer) != null &&
5855	>	(reducer = this.reducer) != null) {
5856	>	double r = this.basis;
5857	>	for (int i = baseIndex, f, h; batch > 0 &&
5858	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5859	>	addToPendingCount(1);
5860	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5861	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5862	>	rights, transformer, r, reducer)).fork();
5863	>	}
5864	>	for (Node<K,V> p; (p = advance()) != null; )
5865	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5866	>	result = r;
5867	>	CountedCompleter<?> c;
5868	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5869	>	@SuppressWarnings("unchecked")
5870	>	MapReduceEntriesToDoubleTask<K,V>
5871	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5872	>	s = t.rights;
5873	>	while (s != null) {
5874	>	t.result = reducer.applyAsDouble(t.result, s.result);
5875	>	s = t.rights = s.nextRight;
5876	>	}
5877	>	}
5878	>	}
5879	>	}
5880	>	}
5881	>
5882	>	@SuppressWarnings("serial")
5883	>	static final class MapReduceMappingsToDoubleTask<K,V>
5884	>	extends BulkTask<K,V,Double> {
5885	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5886	>	final DoubleBinaryOperator reducer;
5887	>	final double basis;
5888	>	double result;
5889	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5890	>	MapReduceMappingsToDoubleTask
5891	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5892	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5893	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5894	>	double basis,
5895	>	DoubleBinaryOperator 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 Double getRawResult() { return result; }
5901	>	public final void compute() {
5902	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5903	>	final DoubleBinaryOperator reducer;
5904	>	if ((transformer = this.transformer) != null &&
5905	>	(reducer = this.reducer) != null) {
5906	>	double 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 MapReduceMappingsToDoubleTask<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.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5916	>	result = r;
5917	>	CountedCompleter<?> c;
5918	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5919	>	@SuppressWarnings("unchecked")
5920	>	MapReduceMappingsToDoubleTask<K,V>
5921	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5922	>	s = t.rights;
5923	>	while (s != null) {
5924	>	t.result = reducer.applyAsDouble(t.result, s.result);
5925	>	s = t.rights = s.nextRight;
5926	>	}
5927	>	}
5928	>	}
5929	>	}
5930	>	}
5931	>
5932	>	@SuppressWarnings("serial")
5933	>	static final class MapReduceKeysToLongTask<K,V>
5934	>	extends BulkTask<K,V,Long> {
5935	>	final ToLongFunction<? super K> transformer;
5936	>	final LongBinaryOperator reducer;
5937	>	final long basis;
5938	>	long result;
5939	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5940	>	MapReduceKeysToLongTask
5941	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5942	>	MapReduceKeysToLongTask<K,V> nextRight,
5943	>	ToLongFunction<? super K> transformer,
5944	>	long basis,
5945	>	LongBinaryOperator reducer) {
5946	>	super(p, b, i, f, t); this.nextRight = nextRight;
5947	>	this.transformer = transformer;
5948	>	this.basis = basis; this.reducer = reducer;
5949	>	}
5950	>	public final Long getRawResult() { return result; }
5951	>	public final void compute() {
5952	>	final ToLongFunction<? super K> transformer;
5953	>	final LongBinaryOperator reducer;
5954	>	if ((transformer = this.transformer) != null &&
5955	>	(reducer = this.reducer) != null) {
5956	>	long r = this.basis;
5957	>	for (int i = baseIndex, f, h; batch > 0 &&
5958	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5959	>	addToPendingCount(1);
5960	>	(rights = new MapReduceKeysToLongTask<K,V>
5961	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5962	>	rights, transformer, r, reducer)).fork();
5963	>	}
5964	>	for (Node<K,V> p; (p = advance()) != null; )
5965	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5966	>	result = r;
5967	>	CountedCompleter<?> c;
5968	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5969	>	@SuppressWarnings("unchecked")
5970	>	MapReduceKeysToLongTask<K,V>
5971	>	t = (MapReduceKeysToLongTask<K,V>)c,
5972	>	s = t.rights;
5973	>	while (s != null) {
5974	>	t.result = reducer.applyAsLong(t.result, s.result);
5975	>	s = t.rights = s.nextRight;
5976	>	}
5977	>	}
5978	>	}
5979	>	}
5980	>	}
5981	>
5982	>	@SuppressWarnings("serial")
5983	>	static final class MapReduceValuesToLongTask<K,V>
5984	>	extends BulkTask<K,V,Long> {
5985	>	final ToLongFunction<? super V> transformer;
5986	>	final LongBinaryOperator reducer;
5987	>	final long basis;
5988	>	long result;
5989	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5990	>	MapReduceValuesToLongTask
5991	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5992	>	MapReduceValuesToLongTask<K,V> nextRight,
5993	>	ToLongFunction<? super V> transformer,
5994	>	long basis,
5995	>	LongBinaryOperator reducer) {
5996	>	super(p, b, i, f, t); this.nextRight = nextRight;
5997	>	this.transformer = transformer;
5998	>	this.basis = basis; this.reducer = reducer;
5999	>	}
6000	>	public final Long getRawResult() { return result; }
6001	>	public final void compute() {
6002	>	final ToLongFunction<? super V> transformer;
6003	>	final LongBinaryOperator reducer;
6004	>	if ((transformer = this.transformer) != null &&
6005	>	(reducer = this.reducer) != null) {
6006	>	long r = this.basis;
6007	>	for (int i = baseIndex, f, h; batch > 0 &&
6008	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6009	>	addToPendingCount(1);
6010	>	(rights = new MapReduceValuesToLongTask<K,V>
6011	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6012	>	rights, transformer, r, reducer)).fork();
6013	>	}
6014	>	for (Node<K,V> p; (p = advance()) != null; )
6015	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
6016	>	result = r;
6017	>	CountedCompleter<?> c;
6018	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6019	>	@SuppressWarnings("unchecked")
6020	>	MapReduceValuesToLongTask<K,V>
6021	>	t = (MapReduceValuesToLongTask<K,V>)c,
6022	>	s = t.rights;
6023	>	while (s != null) {
6024	>	t.result = reducer.applyAsLong(t.result, s.result);
6025	>	s = t.rights = s.nextRight;
6026	>	}
6027	>	}
6028	>	}
6029		}
6030		}
6031	+
6032	+	@SuppressWarnings("serial")
6033	+	static final class MapReduceEntriesToLongTask<K,V>
6034	+	extends BulkTask<K,V,Long> {
6035	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6036	+	final LongBinaryOperator reducer;
6037	+	final long basis;
6038	+	long result;
6039	+	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6040	+	MapReduceEntriesToLongTask
6041	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6042	+	MapReduceEntriesToLongTask<K,V> nextRight,
6043	+	ToLongFunction<Map.Entry<K,V>> transformer,
6044	+	long basis,
6045	+	LongBinaryOperator reducer) {
6046	+	super(p, b, i, f, t); this.nextRight = nextRight;
6047	+	this.transformer = transformer;
6048	+	this.basis = basis; this.reducer = reducer;
6049	+	}
6050	+	public final Long getRawResult() { return result; }
6051	+	public final void compute() {
6052	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6053	+	final LongBinaryOperator reducer;
6054	+	if ((transformer = this.transformer) != null &&
6055	+	(reducer = this.reducer) != null) {
6056	+	long r = this.basis;
6057	+	for (int i = baseIndex, f, h; batch > 0 &&
6058	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6059	+	addToPendingCount(1);
6060	+	(rights = new MapReduceEntriesToLongTask<K,V>
6061	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6062	+	rights, transformer, r, reducer)).fork();
6063	+	}
6064	+	for (Node<K,V> p; (p = advance()) != null; )
6065	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6066	+	result = r;
6067	+	CountedCompleter<?> c;
6068	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6069	+	@SuppressWarnings("unchecked")
6070	+	MapReduceEntriesToLongTask<K,V>
6071	+	t = (MapReduceEntriesToLongTask<K,V>)c,
6072	+	s = t.rights;
6073	+	while (s != null) {
6074	+	t.result = reducer.applyAsLong(t.result, s.result);
6075	+	s = t.rights = s.nextRight;
6076	+	}
6077	+	}
6078	+	}
6079	+	}
6080	+	}
6081	+
6082	+	@SuppressWarnings("serial")
6083	+	static final class MapReduceMappingsToLongTask<K,V>
6084	+	extends BulkTask<K,V,Long> {
6085	+	final ToLongBiFunction<? super K, ? super V> transformer;
6086	+	final LongBinaryOperator reducer;
6087	+	final long basis;
6088	+	long result;
6089	+	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6090	+	MapReduceMappingsToLongTask
6091	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6092	+	MapReduceMappingsToLongTask<K,V> nextRight,
6093	+	ToLongBiFunction<? super K, ? super V> transformer,
6094	+	long basis,
6095	+	LongBinaryOperator reducer) {
6096	+	super(p, b, i, f, t); this.nextRight = nextRight;
6097	+	this.transformer = transformer;
6098	+	this.basis = basis; this.reducer = reducer;
6099	+	}
6100	+	public final Long getRawResult() { return result; }
6101	+	public final void compute() {
6102	+	final ToLongBiFunction<? super K, ? super V> transformer;
6103	+	final LongBinaryOperator reducer;
6104	+	if ((transformer = this.transformer) != null &&
6105	+	(reducer = this.reducer) != null) {
6106	+	long r = this.basis;
6107	+	for (int i = baseIndex, f, h; batch > 0 &&
6108	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6109	+	addToPendingCount(1);
6110	+	(rights = new MapReduceMappingsToLongTask<K,V>
6111	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6112	+	rights, transformer, r, reducer)).fork();
6113	+	}
6114	+	for (Node<K,V> p; (p = advance()) != null; )
6115	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6116	+	result = r;
6117	+	CountedCompleter<?> c;
6118	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6119	+	@SuppressWarnings("unchecked")
6120	+	MapReduceMappingsToLongTask<K,V>
6121	+	t = (MapReduceMappingsToLongTask<K,V>)c,
6122	+	s = t.rights;
6123	+	while (s != null) {
6124	+	t.result = reducer.applyAsLong(t.result, s.result);
6125	+	s = t.rights = s.nextRight;
6126	+	}
6127	+	}
6128	+	}
6129	+	}
6130	+	}
6131	+
6132	+	@SuppressWarnings("serial")
6133	+	static final class MapReduceKeysToIntTask<K,V>
6134	+	extends BulkTask<K,V,Integer> {
6135	+	final ToIntFunction<? super K> transformer;
6136	+	final IntBinaryOperator reducer;
6137	+	final int basis;
6138	+	int result;
6139	+	MapReduceKeysToIntTask<K,V> rights, nextRight;
6140	+	MapReduceKeysToIntTask
6141	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6142	+	MapReduceKeysToIntTask<K,V> nextRight,
6143	+	ToIntFunction<? super K> transformer,
6144	+	int basis,
6145	+	IntBinaryOperator reducer) {
6146	+	super(p, b, i, f, t); this.nextRight = nextRight;
6147	+	this.transformer = transformer;
6148	+	this.basis = basis; this.reducer = reducer;
6149	+	}
6150	+	public final Integer getRawResult() { return result; }
6151	+	public final void compute() {
6152	+	final ToIntFunction<? super K> transformer;
6153	+	final IntBinaryOperator reducer;
6154	+	if ((transformer = this.transformer) != null &&
6155	+	(reducer = this.reducer) != null) {
6156	+	int r = this.basis;
6157	+	for (int i = baseIndex, f, h; batch > 0 &&
6158	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6159	+	addToPendingCount(1);
6160	+	(rights = new MapReduceKeysToIntTask<K,V>
6161	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6162	+	rights, transformer, r, reducer)).fork();
6163	+	}
6164	+	for (Node<K,V> p; (p = advance()) != null; )
6165	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6166	+	result = r;
6167	+	CountedCompleter<?> c;
6168	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6169	+	@SuppressWarnings("unchecked")
6170	+	MapReduceKeysToIntTask<K,V>
6171	+	t = (MapReduceKeysToIntTask<K,V>)c,
6172	+	s = t.rights;
6173	+	while (s != null) {
6174	+	t.result = reducer.applyAsInt(t.result, s.result);
6175	+	s = t.rights = s.nextRight;
6176	+	}
6177	+	}
6178	+	}
6179	+	}
6180	+	}
6181	+
6182	+	@SuppressWarnings("serial")
6183	+	static final class MapReduceValuesToIntTask<K,V>
6184	+	extends BulkTask<K,V,Integer> {
6185	+	final ToIntFunction<? super V> transformer;
6186	+	final IntBinaryOperator reducer;
6187	+	final int basis;
6188	+	int result;
6189	+	MapReduceValuesToIntTask<K,V> rights, nextRight;
6190	+	MapReduceValuesToIntTask
6191	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6192	+	MapReduceValuesToIntTask<K,V> nextRight,
6193	+	ToIntFunction<? super V> transformer,
6194	+	int basis,
6195	+	IntBinaryOperator reducer) {
6196	+	super(p, b, i, f, t); this.nextRight = nextRight;
6197	+	this.transformer = transformer;
6198	+	this.basis = basis; this.reducer = reducer;
6199	+	}
6200	+	public final Integer getRawResult() { return result; }
6201	+	public final void compute() {
6202	+	final ToIntFunction<? super V> transformer;
6203	+	final IntBinaryOperator reducer;
6204	+	if ((transformer = this.transformer) != null &&
6205	+	(reducer = this.reducer) != null) {
6206	+	int r = this.basis;
6207	+	for (int i = baseIndex, f, h; batch > 0 &&
6208	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6209	+	addToPendingCount(1);
6210	+	(rights = new MapReduceValuesToIntTask<K,V>
6211	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6212	+	rights, transformer, r, reducer)).fork();
6213	+	}
6214	+	for (Node<K,V> p; (p = advance()) != null; )
6215	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6216	+	result = r;
6217	+	CountedCompleter<?> c;
6218	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6219	+	@SuppressWarnings("unchecked")
6220	+	MapReduceValuesToIntTask<K,V>
6221	+	t = (MapReduceValuesToIntTask<K,V>)c,
6222	+	s = t.rights;
6223	+	while (s != null) {
6224	+	t.result = reducer.applyAsInt(t.result, s.result);
6225	+	s = t.rights = s.nextRight;
6226	+	}
6227	+	}
6228	+	}
6229	+	}
6230	+	}
6231	+
6232	+	@SuppressWarnings("serial")
6233	+	static final class MapReduceEntriesToIntTask<K,V>
6234	+	extends BulkTask<K,V,Integer> {
6235	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6236	+	final IntBinaryOperator reducer;
6237	+	final int basis;
6238	+	int result;
6239	+	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6240	+	MapReduceEntriesToIntTask
6241	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6242	+	MapReduceEntriesToIntTask<K,V> nextRight,
6243	+	ToIntFunction<Map.Entry<K,V>> transformer,
6244	+	int basis,
6245	+	IntBinaryOperator reducer) {
6246	+	super(p, b, i, f, t); this.nextRight = nextRight;
6247	+	this.transformer = transformer;
6248	+	this.basis = basis; this.reducer = reducer;
6249	+	}
6250	+	public final Integer getRawResult() { return result; }
6251	+	public final void compute() {
6252	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6253	+	final IntBinaryOperator reducer;
6254	+	if ((transformer = this.transformer) != null &&
6255	+	(reducer = this.reducer) != null) {
6256	+	int r = this.basis;
6257	+	for (int i = baseIndex, f, h; batch > 0 &&
6258	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6259	+	addToPendingCount(1);
6260	+	(rights = new MapReduceEntriesToIntTask<K,V>
6261	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6262	+	rights, transformer, r, reducer)).fork();
6263	+	}
6264	+	for (Node<K,V> p; (p = advance()) != null; )
6265	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6266	+	result = r;
6267	+	CountedCompleter<?> c;
6268	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6269	+	@SuppressWarnings("unchecked")
6270	+	MapReduceEntriesToIntTask<K,V>
6271	+	t = (MapReduceEntriesToIntTask<K,V>)c,
6272	+	s = t.rights;
6273	+	while (s != null) {
6274	+	t.result = reducer.applyAsInt(t.result, s.result);
6275	+	s = t.rights = s.nextRight;
6276	+	}
6277	+	}
6278	+	}
6279	+	}
6280	+	}
6281	+
6282	+	@SuppressWarnings("serial")
6283	+	static final class MapReduceMappingsToIntTask<K,V>
6284	+	extends BulkTask<K,V,Integer> {
6285	+	final ToIntBiFunction<? super K, ? super V> transformer;
6286	+	final IntBinaryOperator reducer;
6287	+	final int basis;
6288	+	int result;
6289	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6290	+	MapReduceMappingsToIntTask
6291	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6292	+	MapReduceMappingsToIntTask<K,V> nextRight,
6293	+	ToIntBiFunction<? super K, ? super V> transformer,
6294	+	int basis,
6295	+	IntBinaryOperator reducer) {
6296	+	super(p, b, i, f, t); this.nextRight = nextRight;
6297	+	this.transformer = transformer;
6298	+	this.basis = basis; this.reducer = reducer;
6299	+	}
6300	+	public final Integer getRawResult() { return result; }
6301	+	public final void compute() {
6302	+	final ToIntBiFunction<? super K, ? super V> transformer;
6303	+	final IntBinaryOperator reducer;
6304	+	if ((transformer = this.transformer) != null &&
6305	+	(reducer = this.reducer) != null) {
6306	+	int r = this.basis;
6307	+	for (int i = baseIndex, f, h; batch > 0 &&
6308	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6309	+	addToPendingCount(1);
6310	+	(rights = new MapReduceMappingsToIntTask<K,V>
6311	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6312	+	rights, transformer, r, reducer)).fork();
6313	+	}
6314	+	for (Node<K,V> p; (p = advance()) != null; )
6315	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6316	+	result = r;
6317	+	CountedCompleter<?> c;
6318	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6319	+	@SuppressWarnings("unchecked")
6320	+	MapReduceMappingsToIntTask<K,V>
6321	+	t = (MapReduceMappingsToIntTask<K,V>)c,
6322	+	s = t.rights;
6323	+	while (s != null) {
6324	+	t.result = reducer.applyAsInt(t.result, s.result);
6325	+	s = t.rights = s.nextRight;
6326	+	}
6327	+	}
6328	+	}
6329	+	}
6330	+	}
6331	+
6332	+	// Unsafe mechanics
6333	+	private static final Unsafe U = Unsafe.getUnsafe();
6334	+	private static final long SIZECTL;
6335	+	private static final long TRANSFERINDEX;
6336	+	private static final long BASECOUNT;
6337	+	private static final long CELLSBUSY;
6338	+	private static final long CELLVALUE;
6339	+	private static final int ABASE;
6340	+	private static final int ASHIFT;
6341	+
6342	+	static {
6343	+	try {
6344	+	SIZECTL = U.objectFieldOffset
6345	+	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6346	+	TRANSFERINDEX = U.objectFieldOffset
6347	+	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6348	+	BASECOUNT = U.objectFieldOffset
6349	+	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6350	+	CELLSBUSY = U.objectFieldOffset
6351	+	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6352	+
6353	+	CELLVALUE = U.objectFieldOffset
6354	+	(CounterCell.class.getDeclaredField("value"));
6355	+
6356	+	ABASE = U.arrayBaseOffset(Node[].class);
6357	+	int scale = U.arrayIndexScale(Node[].class);
6358	+	if ((scale & (scale - 1)) != 0)
6359	+	throw new Error("array index scale not a power of two");
6360	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6361	+	} catch (ReflectiveOperationException e) {
6362	+	throw new Error(e);
6363	+	}
6364	+
6365	+	// Reduce the risk of rare disastrous classloading in first call to
6366	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6367	+	Class<?> ensureLoaded = LockSupport.class;
6368	+	}
6369		}

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