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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 1.304 by jsr166, Sun Jan 7 04:59:42 2018 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 Map.Entry} objects do not support method {@code setValue}.
134	>	*
135	>	* <ul>
136	>	* <li>forEach: Performs a given action on each element.
137	>	* A variant form applies a given transformation on each element
138	>	* before performing the action.
139	>	*
140	>	* <li>search: Returns the first available non-null result of
141	>	* applying a given function on each element; skipping further
142	>	* search when a result is found.
143	>	*
144	>	* <li>reduce: Accumulates each element.  The supplied reduction
145	>	* function cannot rely on ordering (more formally, it should be
146	>	* both associative and commutative).  There are five variants:
147	>	*
148	>	* <ul>
149	>	*
150	>	* <li>Plain reductions. (There is not a form of this method for
151	>	* (key, value) function arguments since there is no corresponding
152	>	* return type.)
153	>	*
154	>	* <li>Mapped reductions that accumulate the results of a given
155	>	* function applied to each element.
156	>	*
157	>	* <li>Reductions to scalar doubles, longs, and ints, using a
158	>	* given basis value.
159	>	*
160	>	* </ul>
161	>	* </ul>
162	>	*
163	>	* <p>These bulk operations accept a {@code parallelismThreshold}
164	>	* argument. Methods proceed sequentially if the current map size is
165	>	* estimated to be less than the given threshold. Using a value of
166	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
167	>	* of {@code 1} results in maximal parallelism by partitioning into
168	>	* enough subtasks to fully utilize the {@link
169	>	* ForkJoinPool#commonPool()} that is used for all parallel
170	>	* computations. Normally, you would initially choose one of these
171	>	* extreme values, and then measure performance of using in-between
172	>	* values that trade off overhead versus throughput.
173	>	*
174	>	* <p>The concurrency properties of bulk operations follow
175	>	* from those of ConcurrentHashMap: Any non-null result returned
176	>	* from {@code get(key)} and related access methods bears a
177	>	* happens-before relation with the associated insertion or
178	>	* update.  The result of any bulk operation reflects the
179	>	* composition of these per-element relations (but is not
180	>	* necessarily atomic with respect to the map as a whole unless it
181	>	* is somehow known to be quiescent).  Conversely, because keys
182	>	* and values in the map are never null, null serves as a reliable
183	>	* atomic indicator of the current lack of any result.  To
184	>	* maintain this property, null serves as an implicit basis for
185	>	* all non-scalar reduction operations. For the double, long, and
186	>	* int versions, the basis should be one that, when combined with
187	>	* any other value, returns that other value (more formally, it
188	>	* should be the identity element for the reduction). Most common
189	>	* reductions have these properties; for example, computing a sum
190	>	* with basis 0 or a minimum with basis MAX_VALUE.
191	>	*
192	>	* <p>Search and transformation functions provided as arguments
193	>	* should similarly return null to indicate the lack of any result
194	>	* (in which case it is not used). In the case of mapped
195	>	* reductions, this also enables transformations to serve as
196	>	* filters, returning null (or, in the case of primitive
197	>	* specializations, the identity basis) if the element should not
198	>	* be combined. You can create compound transformations and
199	>	* filterings by composing them yourself under this "null means
200	>	* there is nothing there now" rule before using them in search or
201	>	* reduce operations.
202	>	*
203	>	* <p>Methods accepting and/or returning Entry arguments maintain
204	>	* key-value associations. They may be useful for example when
205	>	* finding the key for the greatest value. Note that "plain" Entry
206	>	* arguments can be supplied using {@code new
207	>	* AbstractMap.SimpleEntry(k,v)}.
208	>	*
209	>	* <p>Bulk operations may complete abruptly, throwing an
210	>	* exception encountered in the application of a supplied
211	>	* function. Bear in mind when handling such exceptions that other
212	>	* concurrently executing functions could also have thrown
213	>	* exceptions, or would have done so if the first exception had
214	>	* not occurred.
215	>	*
216	>	* <p>Speedups for parallel compared to sequential forms are common
217	>	* but not guaranteed.  Parallel operations involving brief functions
218	>	* on small maps may execute more slowly than sequential forms if the
219	>	* underlying work to parallelize the computation is more expensive
220	>	* than the computation itself.  Similarly, parallelization may not
221	>	* lead to much actual parallelism if all processors are busy
222	>	* performing unrelated tasks.
223	>	*
224	>	* <p>All arguments to all task methods must be non-null.
225		*
226		* <p>This class is a member of the
227	<	* <a href="{@docRoot}/../guide/collections/index.html">
227	>	* <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework">
228		* Java Collections Framework</a>.
229		*
230		* @since 1.5
#	Line 70 | Line 232 | import java.io.ObjectOutputStream;
232		* @param <K> the type of keys maintained by this map
233		* @param <V> the type of mapped values
234		*/
235	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
236	<	implements ConcurrentMap<K, V>, Serializable {
235	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
236	>	implements ConcurrentMap<K,V>, Serializable {
237		private static final long serialVersionUID = 7249069246763182397L;
238
239		/*
240	<	* The basic strategy is to subdivide the table among Segments,
241	<	* each of which itself is a concurrently readable hash table.
240	>	* Overview:
241	>	*
242	>	* The primary design goal of this hash table is to maintain
243	>	* concurrent readability (typically method get(), but also
244	>	* iterators and related methods) while minimizing update
245	>	* contention. Secondary goals are to keep space consumption about
246	>	* the same or better than java.util.HashMap, and to support high
247	>	* initial insertion rates on an empty table by many threads.
248	>	*
249	>	* This map usually acts as a binned (bucketed) hash table.  Each
250	>	* key-value mapping is held in a Node.  Most nodes are instances
251	>	* of the basic Node class with hash, key, value, and next
252	>	* fields. However, various subclasses exist: TreeNodes are
253	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
254	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
255	>	* of bins during resizing. ReservationNodes are used as
256	>	* placeholders while establishing values in computeIfAbsent and
257	>	* related methods.  The types TreeBin, ForwardingNode, and
258	>	* ReservationNode do not hold normal user keys, values, or
259	>	* hashes, and are readily distinguishable during search etc
260	>	* because they have negative hash fields and null key and value
261	>	* fields. (These special nodes are either uncommon or transient,
262	>	* so the impact of carrying around some unused fields is
263	>	* insignificant.)
264	>	*
265	>	* The table is lazily initialized to a power-of-two size upon the
266	>	* first insertion.  Each bin in the table normally contains a
267	>	* list of Nodes (most often, the list has only zero or one Node).
268	>	* Table accesses require volatile/atomic reads, writes, and
269	>	* CASes.  Because there is no other way to arrange this without
270	>	* adding further indirections, we use intrinsics
271	>	* (jdk.internal.misc.Unsafe) operations.
272	>	*
273	>	* We use the top (sign) bit of Node hash fields for control
274	>	* purposes -- it is available anyway because of addressing
275	>	* constraints.  Nodes with negative hash fields are specially
276	>	* handled or ignored in map methods.
277	>	*
278	>	* Insertion (via put or its variants) of the first node in an
279	>	* empty bin is performed by just CASing it to the bin.  This is
280	>	* by far the most common case for put operations under most
281	>	* key/hash distributions.  Other update operations (insert,
282	>	* delete, and replace) require locks.  We do not want to waste
283	>	* the space required to associate a distinct lock object with
284	>	* each bin, so instead use the first node of a bin list itself as
285	>	* a lock. Locking support for these locks relies on builtin
286	>	* "synchronized" monitors.
287	>	*
288	>	* Using the first node of a list as a lock does not by itself
289	>	* suffice though: When a node is locked, any update must first
290	>	* validate that it is still the first node after locking it, and
291	>	* retry if not. Because new nodes are always appended to lists,
292	>	* once a node is first in a bin, it remains first until deleted
293	>	* or the bin becomes invalidated (upon resizing).
294	>	*
295	>	* The main disadvantage of per-bin locks is that other update
296	>	* operations on other nodes in a bin list protected by the same
297	>	* lock can stall, for example when user equals() or mapping
298	>	* functions take a long time.  However, statistically, under
299	>	* random hash codes, this is not a common problem.  Ideally, the
300	>	* frequency of nodes in bins follows a Poisson distribution
301	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
302	>	* parameter of about 0.5 on average, given the resizing threshold
303	>	* of 0.75, although with a large variance because of resizing
304	>	* granularity. Ignoring variance, the expected occurrences of
305	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
306	>	* first values are:
307	>	*
308	>	* 0:    0.60653066
309	>	* 1:    0.30326533
310	>	* 2:    0.07581633
311	>	* 3:    0.01263606
312	>	* 4:    0.00157952
313	>	* 5:    0.00015795
314	>	* 6:    0.00001316
315	>	* 7:    0.00000094
316	>	* 8:    0.00000006
317	>	* more: less than 1 in ten million
318	>	*
319	>	* Lock contention probability for two threads accessing distinct
320	>	* elements is roughly 1 / (8 * #elements) under random hashes.
321	>	*
322	>	* Actual hash code distributions encountered in practice
323	>	* sometimes deviate significantly from uniform randomness.  This
324	>	* includes the case when N > (1<<30), so some keys MUST collide.
325	>	* Similarly for dumb or hostile usages in which multiple keys are
326	>	* designed to have identical hash codes or ones that differs only
327	>	* in masked-out high bits. So we use a secondary strategy that
328	>	* applies when the number of nodes in a bin exceeds a
329	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
330	>	* specialized form of red-black trees), bounding search time to
331	>	* O(log N).  Each search step in a TreeBin is at least twice as
332	>	* slow as in a regular list, but given that N cannot exceed
333	>	* (1<<64) (before running out of addresses) this bounds search
334	>	* steps, lock hold times, etc, to reasonable constants (roughly
335	>	* 100 nodes inspected per operation worst case) so long as keys
336	>	* are Comparable (which is very common -- String, Long, etc).
337	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
338	>	* traversal pointers as regular nodes, so can be traversed in
339	>	* iterators in the same way.
340	>	*
341	>	* The table is resized when occupancy exceeds a percentage
342	>	* threshold (nominally, 0.75, but see below).  Any thread
343	>	* noticing an overfull bin may assist in resizing after the
344	>	* initiating thread allocates and sets up the replacement array.
345	>	* However, rather than stalling, these other threads may proceed
346	>	* with insertions etc.  The use of TreeBins shields us from the
347	>	* worst case effects of overfilling while resizes are in
348	>	* progress.  Resizing proceeds by transferring bins, one by one,
349	>	* from the table to the next table. However, threads claim small
350	>	* blocks of indices to transfer (via field transferIndex) before
351	>	* doing so, reducing contention.  A generation stamp in field
352	>	* sizeCtl ensures that resizings do not overlap. Because we are
353	>	* using power-of-two expansion, the elements from each bin must
354	>	* either stay at same index, or move with a power of two
355	>	* offset. We eliminate unnecessary node creation by catching
356	>	* cases where old nodes can be reused because their next fields
357	>	* won't change.  On average, only about one-sixth of them need
358	>	* cloning when a table doubles. The nodes they replace will be
359	>	* garbage collectable as soon as they are no longer referenced by
360	>	* any reader thread that may be in the midst of concurrently
361	>	* traversing table.  Upon transfer, the old table bin contains
362	>	* only a special forwarding node (with hash field "MOVED") that
363	>	* contains the next table as its key. On encountering a
364	>	* forwarding node, access and update operations restart, using
365	>	* the new table.
366	>	*
367	>	* Each bin transfer requires its bin lock, which can stall
368	>	* waiting for locks while resizing. However, because other
369	>	* threads can join in and help resize rather than contend for
370	>	* locks, average aggregate waits become shorter as resizing
371	>	* progresses.  The transfer operation must also ensure that all
372	>	* accessible bins in both the old and new table are usable by any
373	>	* traversal.  This is arranged in part by proceeding from the
374	>	* last bin (table.length - 1) up towards the first.  Upon seeing
375	>	* a forwarding node, traversals (see class Traverser) arrange to
376	>	* move to the new table without revisiting nodes.  To ensure that
377	>	* no intervening nodes are skipped even when moved out of order,
378	>	* a stack (see class TableStack) is created on first encounter of
379	>	* a forwarding node during a traversal, to maintain its place if
380	>	* later processing the current table. The need for these
381	>	* save/restore mechanics is relatively rare, but when one
382	>	* forwarding node is encountered, typically many more will be.
383	>	* So Traversers use a simple caching scheme to avoid creating so
384	>	* many new TableStack nodes. (Thanks to Peter Levart for
385	>	* suggesting use of a stack here.)
386	>	*
387	>	* The traversal scheme also applies to partial traversals of
388	>	* ranges of bins (via an alternate Traverser constructor)
389	>	* to support partitioned aggregate operations.  Also, read-only
390	>	* operations give up if ever forwarded to a null table, which
391	>	* provides support for shutdown-style clearing, which is also not
392	>	* currently implemented.
393	>	*
394	>	* Lazy table initialization minimizes footprint until first use,
395	>	* and also avoids resizings when the first operation is from a
396	>	* putAll, constructor with map argument, or deserialization.
397	>	* These cases attempt to override the initial capacity settings,
398	>	* but harmlessly fail to take effect in cases of races.
399	>	*
400	>	* The element count is maintained using a specialization of
401	>	* LongAdder. We need to incorporate a specialization rather than
402	>	* just use a LongAdder in order to access implicit
403	>	* contention-sensing that leads to creation of multiple
404	>	* CounterCells.  The counter mechanics avoid contention on
405	>	* updates but can encounter cache thrashing if read too
406	>	* frequently during concurrent access. To avoid reading so often,
407	>	* resizing under contention is attempted only upon adding to a
408	>	* bin already holding two or more nodes. Under uniform hash
409	>	* distributions, the probability of this occurring at threshold
410	>	* is around 13%, meaning that only about 1 in 8 puts check
411	>	* threshold (and after resizing, many fewer do so).
412	>	*
413	>	* TreeBins use a special form of comparison for search and
414	>	* related operations (which is the main reason we cannot use
415	>	* existing collections such as TreeMaps). TreeBins contain
416	>	* Comparable elements, but may contain others, as well as
417	>	* elements that are Comparable but not necessarily Comparable for
418	>	* the same T, so we cannot invoke compareTo among them. To handle
419	>	* this, the tree is ordered primarily by hash value, then by
420	>	* Comparable.compareTo order if applicable.  On lookup at a node,
421	>	* if elements are not comparable or compare as 0 then both left
422	>	* and right children may need to be searched in the case of tied
423	>	* hash values. (This corresponds to the full list search that
424	>	* would be necessary if all elements were non-Comparable and had
425	>	* tied hashes.) On insertion, to keep a total ordering (or as
426	>	* close as is required here) across rebalancings, we compare
427	>	* classes and identityHashCodes as tie-breakers. The red-black
428	>	* balancing code is updated from pre-jdk-collections
429	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
430	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
431	>	* Algorithms" (CLR).
432	>	*
433	>	* TreeBins also require an additional locking mechanism.  While
434	>	* list traversal is always possible by readers even during
435	>	* updates, tree traversal is not, mainly because of tree-rotations
436	>	* that may change the root node and/or its linkages.  TreeBins
437	>	* include a simple read-write lock mechanism parasitic on the
438	>	* main bin-synchronization strategy: Structural adjustments
439	>	* associated with an insertion or removal are already bin-locked
440	>	* (and so cannot conflict with other writers) but must wait for
441	>	* ongoing readers to finish. Since there can be only one such
442	>	* waiter, we use a simple scheme using a single "waiter" field to
443	>	* block writers.  However, readers need never block.  If the root
444	>	* lock is held, they proceed along the slow traversal path (via
445	>	* next-pointers) until the lock becomes available or the list is
446	>	* exhausted, whichever comes first. These cases are not fast, but
447	>	* maximize aggregate expected throughput.
448	>	*
449	>	* Maintaining API and serialization compatibility with previous
450	>	* versions of this class introduces several oddities. Mainly: We
451	>	* leave untouched but unused constructor arguments referring to
452	>	* concurrencyLevel. We accept a loadFactor constructor argument,
453	>	* but apply it only to initial table capacity (which is the only
454	>	* time that we can guarantee to honor it.) We also declare an
455	>	* unused "Segment" class that is instantiated in minimal form
456	>	* only when serializing.
457	>	*
458	>	* Also, solely for compatibility with previous versions of this
459	>	* class, it extends AbstractMap, even though all of its methods
460	>	* are overridden, so it is just useless baggage.
461	>	*
462	>	* This file is organized to make things a little easier to follow
463	>	* while reading than they might otherwise: First the main static
464	>	* declarations and utilities, then fields, then main public
465	>	* methods (with a few factorings of multiple public methods into
466	>	* internal ones), then sizing methods, trees, traversers, and
467	>	* bulk operations.
468		*/
469
470		/* ---------------- Constants -------------- */
471
472		/**
473	<	* The default initial capacity for this table,
474	<	* used when not otherwise specified in a constructor.
473	>	* The largest possible table capacity.  This value must be
474	>	* exactly 1<<30 to stay within Java array allocation and indexing
475	>	* bounds for power of two table sizes, and is further required
476	>	* because the top two bits of 32bit hash fields are used for
477	>	* control purposes.
478		*/
479	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
479	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
480
481		/**
482	<	* The default load factor for this table, used when not
483	<	* otherwise specified in a constructor.
482	>	* The default initial table capacity.  Must be a power of 2
483	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
484		*/
485	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
485	>	private static final int DEFAULT_CAPACITY = 16;
486
487		/**
488	<	* The default concurrency level for this table, used when not
489	<	* otherwise specified in a constructor.
488	>	* The largest possible (non-power of two) array size.
489	>	* Needed by toArray and related methods.
490		*/
491	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
491	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
492
493		/**
494	<	* The maximum capacity, used if a higher value is implicitly
495	<	* 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.
494	>	* The default concurrency level for this table. Unused but
495	>	* defined for compatibility with previous versions of this class.
496		*/
497	<	static final int MAXIMUM_CAPACITY = 1 << 30;
497	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
498
499		/**
500	<	* The maximum number of segments to allow; used to bound
501	<	* constructor arguments.
500	>	* The load factor for this table. Overrides of this value in
501	>	* constructors affect only the initial table capacity.  The
502	>	* actual floating point value isn't normally used -- it is
503	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
504	>	* the associated resizing threshold.
505		*/
506	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
506	>	private static final float LOAD_FACTOR = 0.75f;
507
508		/**
509	<	* Number of unsynchronized retries in size and containsValue
510	<	* methods before resorting to locking. This is used to avoid
511	<	* unbounded retries if tables undergo continuous modification
512	<	* which would make it impossible to obtain an accurate result.
509	>	* The bin count threshold for using a tree rather than list for a
510	>	* bin.  Bins are converted to trees when adding an element to a
511	>	* bin with at least this many nodes. The value must be greater
512	>	* than 2, and should be at least 8 to mesh with assumptions in
513	>	* tree removal about conversion back to plain bins upon
514	>	* shrinkage.
515		*/
516	<	static final int RETRIES_BEFORE_LOCK = 2;
123	<
124	<	/* ---------------- Fields -------------- */
516	>	static final int TREEIFY_THRESHOLD = 8;
517
518		/**
519	<	* Mask value for indexing into segments. The upper bits of a
520	<	* key's hash code are used to choose the segment.
519	>	* The bin count threshold for untreeifying a (split) bin during a
520	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
521	>	* most 6 to mesh with shrinkage detection under removal.
522		*/
523	<	final int segmentMask;
523	>	static final int UNTREEIFY_THRESHOLD = 6;
524
525		/**
526	<	* Shift value for indexing within segments.
526	>	* The smallest table capacity for which bins may be treeified.
527	>	* (Otherwise the table is resized if too many nodes in a bin.)
528	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
529	>	* conflicts between resizing and treeification thresholds.
530		*/
531	<	final int segmentShift;
531	>	static final int MIN_TREEIFY_CAPACITY = 64;
532
533		/**
534	<	* The segments, each of which is a specialized hash table
534	>	* Minimum number of rebinnings per transfer step. Ranges are
535	>	* subdivided to allow multiple resizer threads.  This value
536	>	* serves as a lower bound to avoid resizers encountering
537	>	* excessive memory contention.  The value should be at least
538	>	* DEFAULT_CAPACITY.
539		*/
540	<	final Segment<K,V>[] segments;
141	<
142	<	transient Set<K> keySet;
143	<	transient Set<Map.Entry<K,V>> entrySet;
144	<	transient Collection<V> values;
540	>	private static final int MIN_TRANSFER_STRIDE = 16;
541
542	<	/* ---------------- Small Utilities -------------- */
542	>	/**
543	>	* The number of bits used for generation stamp in sizeCtl.
544	>	* Must be at least 6 for 32bit arrays.
545	>	*/
546	>	private static final int RESIZE_STAMP_BITS = 16;
547
548		/**
549	<	* Returns a hash code for non-null Object x.
550	<	* 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
549	>	* The maximum number of threads that can help resize.
550	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
551		*/
552	<	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	<	}
552	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
553
554		/**
555	<	* 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
555	>	* The bit shift for recording size stamp in sizeCtl.
556		*/
557	<	final Segment<K,V> segmentFor(int hash) {
169	<	return segments[(hash >>> segmentShift) & segmentMask];
170	<	}
557	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
558
559	<	/* ---------------- Inner Classes -------------- */
559	>	/*
560	>	* Encodings for Node hash fields. See above for explanation.
561	>	*/
562	>	static final int MOVED     = -1; // hash for forwarding nodes
563	>	static final int TREEBIN   = -2; // hash for roots of trees
564	>	static final int RESERVED  = -3; // hash for transient reservations
565	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
566	>
567	>	/** Number of CPUS, to place bounds on some sizings */
568	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
569
570		/**
571	<	* ConcurrentHashMap list entry. Note that this is never exported
572	<	* out as a user-visible Map.Entry.
573	<	*
574	<	* Because the value field is volatile, not final, it is legal wrt
575	<	* the Java Memory Model for an unsynchronized reader to see null
576	<	* instead of initial value when read via a data race.  Although a
577	<	* reordering leading to this is not likely to ever actually
578	<	* occur, the Segment.readValueUnderLock method is used as a
579	<	* backup in case a null (pre-initialized) value is ever seen in
580	<	* an unsynchronized access method.
571	>	* Serialized pseudo-fields, provided only for jdk7 compatibility.
572	>	* @serialField segments Segment[]
573	>	*   The segments, each of which is a specialized hash table.
574	>	* @serialField segmentMask int
575	>	*   Mask value for indexing into segments. The upper bits of a
576	>	*   key's hash code are used to choose the segment.
577	>	* @serialField segmentShift int
578	>	*   Shift value for indexing within segments.
579	>	*/
580	>	private static final ObjectStreamField[] serialPersistentFields = {
581	>	new ObjectStreamField("segments", Segment[].class),
582	>	new ObjectStreamField("segmentMask", Integer.TYPE),
583	>	new ObjectStreamField("segmentShift", Integer.TYPE),
584	>	};
585	>
586	>	/* ---------------- Nodes -------------- */
587	>
588	>	/**
589	>	* Key-value entry.  This class is never exported out as a
590	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
591	>	* MapEntry below), but can be used for read-only traversals used
592	>	* in bulk tasks.  Subclasses of Node with a negative hash field
593	>	* are special, and contain null keys and values (but are never
594	>	* exported).  Otherwise, keys and vals are never null.
595		*/
596	<	static final class HashEntry<K,V> {
187	<	final K key;
596	>	static class Node<K,V> implements Map.Entry<K,V> {
597		final int hash;
598	<	volatile V value;
599	<	final HashEntry<K,V> next;
598	>	final K key;
599	>	volatile V val;
600	>	volatile Node<K,V> next;
601
602	<	HashEntry(K key, int hash, HashEntry<K,V> next, V value) {
193	<	this.key = key;
602	>	Node(int hash, K key, V val) {
603		this.hash = hash;
604	+	this.key = key;
605	+	this.val = val;
606	+	}
607	+
608	+	Node(int hash, K key, V val, Node<K,V> next) {
609	+	this(hash, key, val);
610		this.next = next;
196	–	this.value = value;
611		}
612
613	<	@SuppressWarnings("unchecked")
614	<	static final <K,V> HashEntry<K,V>[] newArray(int i) {
615	<	return new HashEntry[i];
616	<	}
613	>	public final K getKey()     { return key; }
614	>	public final V getValue()   { return val; }
615	>	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
616	>	public final String toString() {
617	>	return Helpers.mapEntryToString(key, val);
618	>	}
619	>	public final V setValue(V value) {
620	>	throw new UnsupportedOperationException();
621	>	}
622	>
623	>	public final boolean equals(Object o) {
624	>	Object k, v, u; Map.Entry<?,?> e;
625	>	return ((o instanceof Map.Entry) &&
626	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
627	>	(v = e.getValue()) != null &&
628	>	(k == key || k.equals(key)) &&
629	>	(v == (u = val) || v.equals(u)));
630	>	}
631	>
632	>	/**
633	>	* Virtualized support for map.get(); overridden in subclasses.
634	>	*/
635	>	Node<K,V> find(int h, Object k) {
636	>	Node<K,V> e = this;
637	>	if (k != null) {
638	>	do {
639	>	K ek;
640	>	if (e.hash == h &&
641	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
642	>	return e;
643	>	} while ((e = e.next) != null);
644	>	}
645	>	return null;
646	>	}
647		}
648
649	+	/* ---------------- Static utilities -------------- */
650	+
651		/**
652	<	* Segments are specialized versions of hash tables.  This
653	<	* subclasses from ReentrantLock opportunistically, just to
654	<	* simplify some locking and avoid separate construction.
652	>	* Spreads (XORs) higher bits of hash to lower and also forces top
653	>	* bit to 0. Because the table uses power-of-two masking, sets of
654	>	* hashes that vary only in bits above the current mask will
655	>	* always collide. (Among known examples are sets of Float keys
656	>	* holding consecutive whole numbers in small tables.)  So we
657	>	* apply a transform that spreads the impact of higher bits
658	>	* downward. There is a tradeoff between speed, utility, and
659	>	* quality of bit-spreading. Because many common sets of hashes
660	>	* are already reasonably distributed (so don't benefit from
661	>	* spreading), and because we use trees to handle large sets of
662	>	* collisions in bins, we just XOR some shifted bits in the
663	>	* cheapest possible way to reduce systematic lossage, as well as
664	>	* to incorporate impact of the highest bits that would otherwise
665	>	* never be used in index calculations because of table bounds.
666		*/
667	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
668	<	/*
669	<	* 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	<	*/
667	>	static final int spread(int h) {
668	>	return (h ^ (h >>> 16)) & HASH_BITS;
669	>	}
670
671	<	private static final long serialVersionUID = 2249069246763182397L;
671	>	/**
672	>	* Returns a power of two table size for the given desired capacity.
673	>	* See Hackers Delight, sec 3.2
674	>	*/
675	>	private static final int tableSizeFor(int c) {
676	>	int n = c - 1;
677	>	n |= n >>> 1;
678	>	n |= n >>> 2;
679	>	n |= n >>> 4;
680	>	n |= n >>> 8;
681	>	n |= n >>> 16;
682	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
683	>	}
684
685	<	/**
686	<	* The number of elements in this segment's region.
687	<	*/
688	<	transient volatile int count;
685	>	/**
686	>	* Returns x's Class if it is of the form "class C implements
687	>	* Comparable<C>", else null.
688	>	*/
689	>	static Class<?> comparableClassFor(Object x) {
690	>	if (x instanceof Comparable) {
691	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
692	>	if ((c = x.getClass()) == String.class) // bypass checks
693	>	return c;
694	>	if ((ts = c.getGenericInterfaces()) != null) {
695	>	for (int i = 0; i < ts.length; ++i) {
696	>	if (((t = ts[i]) instanceof ParameterizedType) &&
697	>	((p = (ParameterizedType)t).getRawType() ==
698	>	Comparable.class) &&
699	>	(as = p.getActualTypeArguments()) != null &&
700	>	as.length == 1 && as[0] == c) // type arg is c
701	>	return c;
702	>	}
703	>	}
704	>	}
705	>	return null;
706	>	}
707
708	<	/**
709	<	* Number of updates that alter the size of the table. This is
710	<	* used during bulk-read methods to make sure they see a
711	<	* consistent snapshot: If modCounts change during a traversal
712	<	* of segments computing size or checking containsValue, then
713	<	* we might have an inconsistent view of state so (usually)
714	<	* must retry.
715	<	*/
716	<	transient int modCount;
708	>	/**
709	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
710	>	* class), else 0.
711	>	*/
712	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
713	>	static int compareComparables(Class<?> kc, Object k, Object x) {
714	>	return (x == null || x.getClass() != kc ? 0 :
715	>	((Comparable)k).compareTo(x));
716	>	}
717
718	<	/**
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;
718	>	/* ---------------- Table element access -------------- */
719
720	<	/**
721	<	* The per-segment table.
722	<	*/
723	<	transient volatile HashEntry<K,V>[] table;
720	>	/*
721	>	* Atomic access methods are used for table elements as well as
722	>	* elements of in-progress next table while resizing.  All uses of
723	>	* the tab arguments must be null checked by callers.  All callers
724	>	* also paranoically precheck that tab's length is not zero (or an
725	>	* equivalent check), thus ensuring that any index argument taking
726	>	* the form of a hash value anded with (length - 1) is a valid
727	>	* index.  Note that, to be correct wrt arbitrary concurrency
728	>	* errors by users, these checks must operate on local variables,
729	>	* which accounts for some odd-looking inline assignments below.
730	>	* Note that calls to setTabAt always occur within locked regions,
731	>	* and so require only release ordering.
732	>	*/
733	>
734	>	@SuppressWarnings("unchecked")
735	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
736	>	return (Node<K,V>)U.getObjectAcquire(tab, ((long)i << ASHIFT) + ABASE);
737	>	}
738
739	<	/**
740	<	* The load factor for the hash table.  Even though this value
741	<	* is same for all segments, it is replicated to avoid needing
742	<	* links to outer object.
281	<	* @serial
282	<	*/
283	<	final float loadFactor;
739	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
740	>	Node<K,V> c, Node<K,V> v) {
741	>	return U.compareAndSetObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
742	>	}
743
744	<	Segment(int initialCapacity, float lf) {
745	<	loadFactor = lf;
746	<	setTable(HashEntry.<K,V>newArray(initialCapacity));
288	<	}
744	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
745	>	U.putObjectRelease(tab, ((long)i << ASHIFT) + ABASE, v);
746	>	}
747
748	<	@SuppressWarnings("unchecked")
291	<	static final <K,V> Segment<K,V>[] newArray(int i) {
292	<	return new Segment[i];
293	<	}
748	>	/* ---------------- Fields -------------- */
749
750	<	/**
751	<	* Sets table to new HashEntry array.
752	<	* Call only while holding lock or in constructor.
753	<	*/
754	<	void setTable(HashEntry<K,V>[] newTable) {
300	<	threshold = (int)(newTable.length * loadFactor);
301	<	table = newTable;
302	<	}
750	>	/**
751	>	* The array of bins. Lazily initialized upon first insertion.
752	>	* Size is always a power of two. Accessed directly by iterators.
753	>	*/
754	>	transient volatile Node<K,V>[] table;
755
756	<	/**
757	<	* Returns properly casted first entry of bin for given hash.
758	<	*/
759	<	HashEntry<K,V> getFirst(int hash) {
308	<	HashEntry<K,V>[] tab = table;
309	<	return tab[hash & (tab.length - 1)];
310	<	}
756	>	/**
757	>	* The next table to use; non-null only while resizing.
758	>	*/
759	>	private transient volatile Node<K,V>[] nextTable;
760
761	<	/**
762	<	* Reads value field of an entry under lock. Called if value
763	<	* field ever appears to be null. This is possible only if a
764	<	* compiler happens to reorder a HashEntry initialization with
765	<	* its table assignment, which is legal under memory model
766	<	* 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	<	}
761	>	/**
762	>	* Base counter value, used mainly when there is no contention,
763	>	* but also as a fallback during table initialization
764	>	* races. Updated via CAS.
765	>	*/
766	>	private transient volatile long baseCount;
767
768	<	/* Specialized implementations of map methods */
768	>	/**
769	>	* Table initialization and resizing control.  When negative, the
770	>	* table is being initialized or resized: -1 for initialization,
771	>	* else -(1 + the number of active resizing threads).  Otherwise,
772	>	* when table is null, holds the initial table size to use upon
773	>	* creation, or 0 for default. After initialization, holds the
774	>	* next element count value upon which to resize the table.
775	>	*/
776	>	private transient volatile int sizeCtl;
777
778	<	V get(Object key, int hash) {
779	<	if (count != 0) { // read-volatile
780	<	HashEntry<K,V> e = getFirst(hash);
781	<	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	<	}
778	>	/**
779	>	* The next table index (plus one) to split while resizing.
780	>	*/
781	>	private transient volatile int transferIndex;
782
783	<	boolean containsKey(Object key, int hash) {
784	<	if (count != 0) { // read-volatile
785	<	HashEntry<K,V> e = getFirst(hash);
786	<	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	<	}
783	>	/**
784	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
785	>	*/
786	>	private transient volatile int cellsBusy;
787
788	<	boolean containsValue(Object value) {
789	<	if (count != 0) { // read-volatile
790	<	HashEntry<K,V>[] tab = table;
791	<	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	<	}
788	>	/**
789	>	* Table of counter cells. When non-null, size is a power of 2.
790	>	*/
791	>	private transient volatile CounterCell[] counterCells;
792
793	<	boolean replace(K key, int hash, V oldValue, V newValue) {
794	<	lock();
795	<	try {
796	<	HashEntry<K,V> e = getFirst(hash);
797	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
798	<	e = e.next;
799	<
800	<	boolean replaced = false;
801	<	if (e != null && oldValue.equals(e.value)) {
802	<	replaced = true;
803	<	e.value = newValue;
804	<	}
805	<	return replaced;
806	<	} finally {
807	<	unlock();
793	>	// views
794	>	private transient KeySetView<K,V> keySet;
795	>	private transient ValuesView<K,V> values;
796	>	private transient EntrySetView<K,V> entrySet;
797	>
798	>
799	>	/* ---------------- Public operations -------------- */
800	>
801	>	/**
802	>	* Creates a new, empty map with the default initial table size (16).
803	>	*/
804	>	public ConcurrentHashMap() {
805	>	}
806	>
807	>	/**
808	>	* Creates a new, empty map with an initial table size
809	>	* accommodating the specified number of elements without the need
810	>	* to dynamically resize.
811	>	*
812	>	* @param initialCapacity The implementation performs internal
813	>	* sizing to accommodate this many elements.
814	>	* @throws IllegalArgumentException if the initial capacity of
815	>	* elements is negative
816	>	*/
817	>	public ConcurrentHashMap(int initialCapacity) {
818	>	if (initialCapacity < 0)
819	>	throw new IllegalArgumentException();
820	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
821	>	MAXIMUM_CAPACITY :
822	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
823	>	this.sizeCtl = cap;
824	>	}
825	>
826	>	/**
827	>	* Creates a new map with the same mappings as the given map.
828	>	*
829	>	* @param m the map
830	>	*/
831	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
832	>	this.sizeCtl = DEFAULT_CAPACITY;
833	>	putAll(m);
834	>	}
835	>
836	>	/**
837	>	* Creates a new, empty map with an initial table size based on
838	>	* the given number of elements ({@code initialCapacity}) and
839	>	* initial table density ({@code loadFactor}).
840	>	*
841	>	* @param initialCapacity the initial capacity. The implementation
842	>	* performs internal sizing to accommodate this many elements,
843	>	* given the specified load factor.
844	>	* @param loadFactor the load factor (table density) for
845	>	* establishing the initial table size
846	>	* @throws IllegalArgumentException if the initial capacity of
847	>	* elements is negative or the load factor is nonpositive
848	>	*
849	>	* @since 1.6
850	>	*/
851	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
852	>	this(initialCapacity, loadFactor, 1);
853	>	}
854	>
855	>	/**
856	>	* Creates a new, empty map with an initial table size based on
857	>	* the given number of elements ({@code initialCapacity}), table
858	>	* density ({@code loadFactor}), and number of concurrently
859	>	* updating threads ({@code concurrencyLevel}).
860	>	*
861	>	* @param initialCapacity the initial capacity. The implementation
862	>	* performs internal sizing to accommodate this many elements,
863	>	* given the specified load factor.
864	>	* @param loadFactor the load factor (table density) for
865	>	* establishing the initial table size
866	>	* @param concurrencyLevel the estimated number of concurrently
867	>	* updating threads. The implementation may use this value as
868	>	* a sizing hint.
869	>	* @throws IllegalArgumentException if the initial capacity is
870	>	* negative or the load factor or concurrencyLevel are
871	>	* nonpositive
872	>	*/
873	>	public ConcurrentHashMap(int initialCapacity,
874	>	float loadFactor, int concurrencyLevel) {
875	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
876	>	throw new IllegalArgumentException();
877	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
878	>	initialCapacity = concurrencyLevel;   // as estimated threads
879	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
880	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
881	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
882	>	this.sizeCtl = cap;
883	>	}
884	>
885	>	// Original (since JDK1.2) Map methods
886	>
887	>	/**
888	>	* {@inheritDoc}
889	>	*/
890	>	public int size() {
891	>	long n = sumCount();
892	>	return ((n < 0L) ? 0 :
893	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
894	>	(int)n);
895	>	}
896	>
897	>	/**
898	>	* {@inheritDoc}
899	>	*/
900	>	public boolean isEmpty() {
901	>	return sumCount() <= 0L; // ignore transient negative values
902	>	}
903	>
904	>	/**
905	>	* Returns the value to which the specified key is mapped,
906	>	* or {@code null} if this map contains no mapping for the key.
907	>	*
908	>	* <p>More formally, if this map contains a mapping from a key
909	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
910	>	* then this method returns {@code v}; otherwise it returns
911	>	* {@code null}.  (There can be at most one such mapping.)
912	>	*
913	>	* @throws NullPointerException if the specified key is null
914	>	*/
915	>	public V get(Object key) {
916	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
917	>	int h = spread(key.hashCode());
918	>	if ((tab = table) != null && (n = tab.length) > 0 &&
919	>	(e = tabAt(tab, (n - 1) & h)) != null) {
920	>	if ((eh = e.hash) == h) {
921	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
922	>	return e.val;
923	>	}
924	>	else if (eh < 0)
925	>	return (p = e.find(h, key)) != null ? p.val : null;
926	>	while ((e = e.next) != null) {
927	>	if (e.hash == h &&
928	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
929	>	return e.val;
930		}
931		}
932	+	return null;
933	+	}
934
935	<	V replace(K key, int hash, V newValue) {
936	<	lock();
937	<	try {
938	<	HashEntry<K,V> e = getFirst(hash);
939	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
940	<	e = e.next;
941	<
942	<	V oldValue = null;
943	<	if (e != null) {
944	<	oldValue = e.value;
945	<	e.value = newValue;
946	<	}
947	<	return oldValue;
948	<	} finally {
949	<	unlock();
935	>	/**
936	>	* Tests if the specified object is a key in this table.
937	>	*
938	>	* @param  key possible key
939	>	* @return {@code true} if and only if the specified object
940	>	*         is a key in this table, as determined by the
941	>	*         {@code equals} method; {@code false} otherwise
942	>	* @throws NullPointerException if the specified key is null
943	>	*/
944	>	public boolean containsKey(Object key) {
945	>	return get(key) != null;
946	>	}
947	>
948	>	/**
949	>	* Returns {@code true} if this map maps one or more keys to the
950	>	* specified value. Note: This method may require a full traversal
951	>	* of the map, and is much slower than method {@code containsKey}.
952	>	*
953	>	* @param value value whose presence in this map is to be tested
954	>	* @return {@code true} if this map maps one or more keys to the
955	>	*         specified value
956	>	* @throws NullPointerException if the specified value is null
957	>	*/
958	>	public boolean containsValue(Object value) {
959	>	if (value == null)
960	>	throw new NullPointerException();
961	>	Node<K,V>[] t;
962	>	if ((t = table) != null) {
963	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
964	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
965	>	V v;
966	>	if ((v = p.val) == value || (v != null && value.equals(v)))
967	>	return true;
968		}
969		}
970	+	return false;
971	+	}
972
973	+	/**
974	+	* Maps the specified key to the specified value in this table.
975	+	* Neither the key nor the value can be null.
976	+	*
977	+	* <p>The value can be retrieved by calling the {@code get} method
978	+	* with a key that is equal to the original key.
979	+	*
980	+	* @param key key with which the specified value is to be associated
981	+	* @param value value to be associated with the specified key
982	+	* @return the previous value associated with {@code key}, or
983	+	*         {@code null} if there was no mapping for {@code key}
984	+	* @throws NullPointerException if the specified key or value is null
985	+	*/
986	+	public V put(K key, V value) {
987	+	return putVal(key, value, false);
988	+	}
989
990	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
991	<	lock();
992	<	try {
993	<	int c = count;
994	<	if (c++ > threshold) // ensure capacity
995	<	rehash();
996	<	HashEntry<K,V>[] tab = table;
997	<	int index = hash & (tab.length - 1);
998	<	HashEntry<K,V> first = tab[index];
999	<	HashEntry<K,V> e = first;
1000	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
1001	<	e = e.next;
1002	<
1003	<	V oldValue;
1004	<	if (e != null) {
1005	<	oldValue = e.value;
1006	<	if (!onlyIfAbsent)
1007	<	e.value = value;
990	>	/** Implementation for put and putIfAbsent */
991	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
992	>	if (key == null || value == null) throw new NullPointerException();
993	>	int hash = spread(key.hashCode());
994	>	int binCount = 0;
995	>	for (Node<K,V>[] tab = table;;) {
996	>	Node<K,V> f; int n, i, fh; K fk; V fv;
997	>	if (tab == null || (n = tab.length) == 0)
998	>	tab = initTable();
999	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
1000	>	if (casTabAt(tab, i, null, new Node<K,V>(hash, key, value)))
1001	>	break;                   // no lock when adding to empty bin
1002	>	}
1003	>	else if ((fh = f.hash) == MOVED)
1004	>	tab = helpTransfer(tab, f);
1005	>	else if (onlyIfAbsent // check first node without acquiring lock
1006	>	&& fh == hash
1007	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
1008	>	&& (fv = f.val) != null)
1009	>	return fv;
1010	>	else {
1011	>	V oldVal = null;
1012	>	synchronized (f) {
1013	>	if (tabAt(tab, i) == f) {
1014	>	if (fh >= 0) {
1015	>	binCount = 1;
1016	>	for (Node<K,V> e = f;; ++binCount) {
1017	>	K ek;
1018	>	if (e.hash == hash &&
1019	>	((ek = e.key) == key ||
1020	>	(ek != null && key.equals(ek)))) {
1021	>	oldVal = e.val;
1022	>	if (!onlyIfAbsent)
1023	>	e.val = value;
1024	>	break;
1025	>	}
1026	>	Node<K,V> pred = e;
1027	>	if ((e = e.next) == null) {
1028	>	pred.next = new Node<K,V>(hash, key, value);
1029	>	break;
1030	>	}
1031	>	}
1032	>	}
1033	>	else if (f instanceof TreeBin) {
1034	>	Node<K,V> p;
1035	>	binCount = 2;
1036	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1037	>	value)) != null) {
1038	>	oldVal = p.val;
1039	>	if (!onlyIfAbsent)
1040	>	p.val = value;
1041	>	}
1042	>	}
1043	>	else if (f instanceof ReservationNode)
1044	>	throw new IllegalStateException("Recursive update");
1045	>	}
1046		}
1047	<	else {
1048	<	oldValue = null;
1049	<	++modCount;
1050	<	tab[index] = new HashEntry<K,V>(key, hash, first, value);
1051	<	count = c; // write-volatile
1047	>	if (binCount != 0) {
1048	>	if (binCount >= TREEIFY_THRESHOLD)
1049	>	treeifyBin(tab, i);
1050	>	if (oldVal != null)
1051	>	return oldVal;
1052	>	break;
1053		}
437	–	return oldValue;
438	–	} finally {
439	–	unlock();
1054		}
1055		}
1056	+	addCount(1L, binCount);
1057	+	return null;
1058	+	}
1059
1060	<	void rehash() {
1061	<	HashEntry<K,V>[] oldTable = table;
1062	<	int oldCapacity = oldTable.length;
1063	<	if (oldCapacity >= MAXIMUM_CAPACITY)
1064	<	return;
1060	>	/**
1061	>	* Copies all of the mappings from the specified map to this one.
1062	>	* These mappings replace any mappings that this map had for any of the
1063	>	* keys currently in the specified map.
1064	>	*
1065	>	* @param m mappings to be stored in this map
1066	>	*/
1067	>	public void putAll(Map<? extends K, ? extends V> m) {
1068	>	tryPresize(m.size());
1069	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1070	>	putVal(e.getKey(), e.getValue(), false);
1071	>	}
1072
1073	<	/*
1074	<	* Reclassify nodes in each list to new Map.  Because we are
1075	<	* using power-of-two expansion, the elements from each bin
1076	<	* must either stay at same index, or move with a power of two
1077	<	* offset. We eliminate unnecessary node creation by catching
1078	<	* cases where old nodes can be reused because their next
1079	<	* fields won't change. Statistically, at the default
1080	<	* threshold, only about one-sixth of them need cloning when
1081	<	* a table doubles. The nodes they replace will be garbage
1082	<	* collectable as soon as they are no longer referenced by any
1083	<	* reader thread that may be in the midst of traversing table
1084	<	* 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;
1073	>	/**
1074	>	* Removes the key (and its corresponding value) from this map.
1075	>	* This method does nothing if the key is not in the map.
1076	>	*
1077	>	* @param  key the key that needs to be removed
1078	>	* @return the previous value associated with {@code key}, or
1079	>	*         {@code null} if there was no mapping for {@code key}
1080	>	* @throws NullPointerException if the specified key is null
1081	>	*/
1082	>	public V remove(Object key) {
1083	>	return replaceNode(key, null, null);
1084	>	}
1085
1086	<	else {
1087	<	// Reuse trailing consecutive sequence at same slot
1088	<	HashEntry<K,V> lastRun = e;
1089	<	int lastIdx = idx;
1090	<	for (HashEntry<K,V> last = next;
1091	<	last != null;
1092	<	last = last.next) {
1093	<	int k = last.hash & sizeMask;
1094	<	if (k != lastIdx) {
1095	<	lastIdx = k;
1096	<	lastRun = last;
1086	>	/**
1087	>	* Implementation for the four public remove/replace methods:
1088	>	* Replaces node value with v, conditional upon match of cv if
1089	>	* non-null.  If resulting value is null, delete.
1090	>	*/
1091	>	final V replaceNode(Object key, V value, Object cv) {
1092	>	int hash = spread(key.hashCode());
1093	>	for (Node<K,V>[] tab = table;;) {
1094	>	Node<K,V> f; int n, i, fh;
1095	>	if (tab == null || (n = tab.length) == 0 ||
1096	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1097	>	break;
1098	>	else if ((fh = f.hash) == MOVED)
1099	>	tab = helpTransfer(tab, f);
1100	>	else {
1101	>	V oldVal = null;
1102	>	boolean validated = false;
1103	>	synchronized (f) {
1104	>	if (tabAt(tab, i) == f) {
1105	>	if (fh >= 0) {
1106	>	validated = true;
1107	>	for (Node<K,V> e = f, pred = null;;) {
1108	>	K ek;
1109	>	if (e.hash == hash &&
1110	>	((ek = e.key) == key ||
1111	>	(ek != null && key.equals(ek)))) {
1112	>	V ev = e.val;
1113	>	if (cv == null || cv == ev ||
1114	>	(ev != null && cv.equals(ev))) {
1115	>	oldVal = ev;
1116	>	if (value != null)
1117	>	e.val = value;
1118	>	else if (pred != null)
1119	>	pred.next = e.next;
1120	>	else
1121	>	setTabAt(tab, i, e.next);
1122	>	}
1123	>	break;
1124	>	}
1125	>	pred = e;
1126	>	if ((e = e.next) == null)
1127	>	break;
1128		}
1129		}
1130	<	newTable[lastIdx] = lastRun;
1131	<
1132	<	// Clone all remaining nodes
1133	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1134	<	int k = p.hash & sizeMask;
1135	<	HashEntry<K,V> n = newTable[k];
1136	<	newTable[k] = new HashEntry<K,V>(p.key, p.hash,
1137	<	n, p.value);
1130	>	else if (f instanceof TreeBin) {
1131	>	validated = true;
1132	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1133	>	TreeNode<K,V> r, p;
1134	>	if ((r = t.root) != null &&
1135	>	(p = r.findTreeNode(hash, key, null)) != null) {
1136	>	V pv = p.val;
1137	>	if (cv == null || cv == pv ||
1138	>	(pv != null && cv.equals(pv))) {
1139	>	oldVal = pv;
1140	>	if (value != null)
1141	>	p.val = value;
1142	>	else if (t.removeTreeNode(p))
1143	>	setTabAt(tab, i, untreeify(t.first));
1144	>	}
1145	>	}
1146		}
1147	+	else if (f instanceof ReservationNode)
1148	+	throw new IllegalStateException("Recursive update");
1149		}
1150		}
1151	<	}
1152	<	table = newTable;
1153	<	}
1154	<
1155	<	/**
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
1151	>	if (validated) {
1152	>	if (oldVal != null) {
1153	>	if (value == null)
1154	>	addCount(-1L, -1);
1155	>	return oldVal;
1156		}
1157	+	break;
1158		}
538	–	return oldValue;
539	–	} finally {
540	–	unlock();
1159		}
1160		}
1161	+	return null;
1162	+	}
1163
1164	<	void clear() {
1165	<	if (count != 0) {
1166	<	lock();
1167	<	try {
1168	<	HashEntry<K,V>[] tab = table;
1169	<	for (int i = 0; i < tab.length ; i++)
1170	<	tab[i] = null;
1171	<	++modCount;
1172	<	count = 0; // write-volatile
1173	<	} finally {
1174	<	unlock();
1164	>	/**
1165	>	* Removes all of the mappings from this map.
1166	>	*/
1167	>	public void clear() {
1168	>	long delta = 0L; // negative number of deletions
1169	>	int i = 0;
1170	>	Node<K,V>[] tab = table;
1171	>	while (tab != null && i < tab.length) {
1172	>	int fh;
1173	>	Node<K,V> f = tabAt(tab, i);
1174	>	if (f == null)
1175	>	++i;
1176	>	else if ((fh = f.hash) == MOVED) {
1177	>	tab = helpTransfer(tab, f);
1178	>	i = 0; // restart
1179	>	}
1180	>	else {
1181	>	synchronized (f) {
1182	>	if (tabAt(tab, i) == f) {
1183	>	Node<K,V> p = (fh >= 0 ? f :
1184	>	(f instanceof TreeBin) ?
1185	>	((TreeBin<K,V>)f).first : null);
1186	>	while (p != null) {
1187	>	--delta;
1188	>	p = p.next;
1189	>	}
1190	>	setTabAt(tab, i++, null);
1191	>	}
1192		}
1193		}
1194		}
1195	+	if (delta != 0L)
1196	+	addCount(delta, -1);
1197	+	}
1198	+
1199	+	/**
1200	+	* Returns a {@link Set} view of the keys contained in this map.
1201	+	* The set is backed by the map, so changes to the map are
1202	+	* reflected in the set, and vice-versa. The set supports element
1203	+	* removal, which removes the corresponding mapping from this map,
1204	+	* via the {@code Iterator.remove}, {@code Set.remove},
1205	+	* {@code removeAll}, {@code retainAll}, and {@code clear}
1206	+	* operations.  It does not support the {@code add} or
1207	+	* {@code addAll} operations.
1208	+	*
1209	+	* <p>The view's iterators and spliterators are
1210	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1211	+	*
1212	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1213	+	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1214	+	*
1215	+	* @return the set view
1216	+	*/
1217	+	public KeySetView<K,V> keySet() {
1218	+	KeySetView<K,V> ks;
1219	+	if ((ks = keySet) != null) return ks;
1220	+	return keySet = new KeySetView<K,V>(this, null);
1221	+	}
1222	+
1223	+	/**
1224	+	* Returns a {@link Collection} view of the values contained in this map.
1225	+	* The collection is backed by the map, so changes to the map are
1226	+	* reflected in the collection, and vice-versa.  The collection
1227	+	* supports element removal, which removes the corresponding
1228	+	* mapping from this map, via the {@code Iterator.remove},
1229	+	* {@code Collection.remove}, {@code removeAll},
1230	+	* {@code retainAll}, and {@code clear} operations.  It does not
1231	+	* support the {@code add} or {@code addAll} operations.
1232	+	*
1233	+	* <p>The view's iterators and spliterators are
1234	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1235	+	*
1236	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1237	+	* and {@link Spliterator#NONNULL}.
1238	+	*
1239	+	* @return the collection view
1240	+	*/
1241	+	public Collection<V> values() {
1242	+	ValuesView<K,V> vs;
1243	+	if ((vs = values) != null) return vs;
1244	+	return values = new ValuesView<K,V>(this);
1245		}
1246
1247	+	/**
1248	+	* Returns a {@link Set} view of the mappings contained in this map.
1249	+	* The set is backed by the map, so changes to the map are
1250	+	* reflected in the set, and vice-versa.  The set supports element
1251	+	* removal, which removes the corresponding mapping from the map,
1252	+	* via the {@code Iterator.remove}, {@code Set.remove},
1253	+	* {@code removeAll}, {@code retainAll}, and {@code clear}
1254	+	* operations.
1255	+	*
1256	+	* <p>The view's iterators and spliterators are
1257	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1258	+	*
1259	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1260	+	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1261	+	*
1262	+	* @return the set view
1263	+	*/
1264	+	public Set<Map.Entry<K,V>> entrySet() {
1265	+	EntrySetView<K,V> es;
1266	+	if ((es = entrySet) != null) return es;
1267	+	return entrySet = new EntrySetView<K,V>(this);
1268	+	}
1269
1270	+	/**
1271	+	* Returns the hash code value for this {@link Map}, i.e.,
1272	+	* the sum of, for each key-value pair in the map,
1273	+	* {@code key.hashCode() ^ value.hashCode()}.
1274	+	*
1275	+	* @return the hash code value for this map
1276	+	*/
1277	+	public int hashCode() {
1278	+	int h = 0;
1279	+	Node<K,V>[] t;
1280	+	if ((t = table) != null) {
1281	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1282	+	for (Node<K,V> p; (p = it.advance()) != null; )
1283	+	h += p.key.hashCode() ^ p.val.hashCode();
1284	+	}
1285	+	return h;
1286	+	}
1287
1288	<	/* ---------------- Public operations -------------- */
1288	>	/**
1289	>	* Returns a string representation of this map.  The string
1290	>	* representation consists of a list of key-value mappings (in no
1291	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1292	>	* mappings are separated by the characters {@code ", "} (comma
1293	>	* and space).  Each key-value mapping is rendered as the key
1294	>	* followed by an equals sign ("{@code =}") followed by the
1295	>	* associated value.
1296	>	*
1297	>	* @return a string representation of this map
1298	>	*/
1299	>	public String toString() {
1300	>	Node<K,V>[] t;
1301	>	int f = (t = table) == null ? 0 : t.length;
1302	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1303	>	StringBuilder sb = new StringBuilder();
1304	>	sb.append('{');
1305	>	Node<K,V> p;
1306	>	if ((p = it.advance()) != null) {
1307	>	for (;;) {
1308	>	K k = p.key;
1309	>	V v = p.val;
1310	>	sb.append(k == this ? "(this Map)" : k);
1311	>	sb.append('=');
1312	>	sb.append(v == this ? "(this Map)" : v);
1313	>	if ((p = it.advance()) == null)
1314	>	break;
1315	>	sb.append(',').append(' ');
1316	>	}
1317	>	}
1318	>	return sb.append('}').toString();
1319	>	}
1320
1321		/**
1322	<	* Creates a new, empty map with the specified initial
1323	<	* capacity, load factor and concurrency level.
1322	>	* Compares the specified object with this map for equality.
1323	>	* Returns {@code true} if the given object is a map with the same
1324	>	* mappings as this map.  This operation may return misleading
1325	>	* results if either map is concurrently modified during execution
1326	>	* of this method.
1327		*
1328	<	* @param initialCapacity the initial capacity. The implementation
1329	<	* 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.
1328	>	* @param o object to be compared for equality with this map
1329	>	* @return {@code true} if the specified object is equal to this map
1330		*/
1331	<	public ConcurrentHashMap(int initialCapacity,
1332	<	float loadFactor, int concurrencyLevel) {
1333	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
1334	<	throw new IllegalArgumentException();
1331	>	public boolean equals(Object o) {
1332	>	if (o != this) {
1333	>	if (!(o instanceof Map))
1334	>	return false;
1335	>	Map<?,?> m = (Map<?,?>) o;
1336	>	Node<K,V>[] t;
1337	>	int f = (t = table) == null ? 0 : t.length;
1338	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1339	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1340	>	V val = p.val;
1341	>	Object v = m.get(p.key);
1342	>	if (v == null || (v != val && !v.equals(val)))
1343	>	return false;
1344	>	}
1345	>	for (Map.Entry<?,?> e : m.entrySet()) {
1346	>	Object mk, mv, v;
1347	>	if ((mk = e.getKey()) == null ||
1348	>	(mv = e.getValue()) == null ||
1349	>	(v = get(mk)) == null ||
1350	>	(mv != v && !mv.equals(v)))
1351	>	return false;
1352	>	}
1353	>	}
1354	>	return true;
1355	>	}
1356
1357	<	if (concurrencyLevel > MAX_SEGMENTS)
1358	<	concurrencyLevel = MAX_SEGMENTS;
1357	>	/**
1358	>	* Stripped-down version of helper class used in previous version,
1359	>	* declared for the sake of serialization compatibility.
1360	>	*/
1361	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1362	>	private static final long serialVersionUID = 2249069246763182397L;
1363	>	final float loadFactor;
1364	>	Segment(float lf) { this.loadFactor = lf; }
1365	>	}
1366
1367	<	// Find power-of-two sizes best matching arguments
1367	>	/**
1368	>	* Saves this map to a stream (that is, serializes it).
1369	>	*
1370	>	* @param s the stream
1371	>	* @throws java.io.IOException if an I/O error occurs
1372	>	* @serialData
1373	>	* the serialized fields, followed by the key (Object) and value
1374	>	* (Object) for each key-value mapping, followed by a null pair.
1375	>	* The key-value mappings are emitted in no particular order.
1376	>	*/
1377	>	private void writeObject(java.io.ObjectOutputStream s)
1378	>	throws java.io.IOException {
1379	>	// For serialization compatibility
1380	>	// Emulate segment calculation from previous version of this class
1381		int sshift = 0;
1382		int ssize = 1;
1383	<	while (ssize < concurrencyLevel) {
1383	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1384		++sshift;
1385		ssize <<= 1;
1386		}
1387	<	segmentShift = 32 - sshift;
1388	<	segmentMask = ssize - 1;
1389	<	this.segments = Segment.newArray(ssize);
1390	<
1391	<	if (initialCapacity > MAXIMUM_CAPACITY)
1392	<	initialCapacity = MAXIMUM_CAPACITY;
1393	<	int c = initialCapacity / ssize;
1394	<	if (c * ssize < initialCapacity)
1395	<	++c;
1396	<	int cap = 1;
1397	<	while (cap < c)
1398	<	cap <<= 1;
1387	>	int segmentShift = 32 - sshift;
1388	>	int segmentMask = ssize - 1;
1389	>	@SuppressWarnings("unchecked")
1390	>	Segment<K,V>[] segments = (Segment<K,V>[])
1391	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1392	>	for (int i = 0; i < segments.length; ++i)
1393	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1394	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1395	>	streamFields.put("segments", segments);
1396	>	streamFields.put("segmentShift", segmentShift);
1397	>	streamFields.put("segmentMask", segmentMask);
1398	>	s.writeFields();
1399	>
1400	>	Node<K,V>[] t;
1401	>	if ((t = table) != null) {
1402	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1403	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1404	>	s.writeObject(p.key);
1405	>	s.writeObject(p.val);
1406	>	}
1407	>	}
1408	>	s.writeObject(null);
1409	>	s.writeObject(null);
1410	>	}
1411
1412	<	for (int i = 0; i < this.segments.length; ++i)
1413	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
1412	>	/**
1413	>	* Reconstitutes this map from a stream (that is, deserializes it).
1414	>	* @param s the stream
1415	>	* @throws ClassNotFoundException if the class of a serialized object
1416	>	*         could not be found
1417	>	* @throws java.io.IOException if an I/O error occurs
1418	>	*/
1419	>	private void readObject(java.io.ObjectInputStream s)
1420	>	throws java.io.IOException, ClassNotFoundException {
1421	>	/*
1422	>	* To improve performance in typical cases, we create nodes
1423	>	* while reading, then place in table once size is known.
1424	>	* However, we must also validate uniqueness and deal with
1425	>	* overpopulated bins while doing so, which requires
1426	>	* specialized versions of putVal mechanics.
1427	>	*/
1428	>	sizeCtl = -1; // force exclusion for table construction
1429	>	s.defaultReadObject();
1430	>	long size = 0L;
1431	>	Node<K,V> p = null;
1432	>	for (;;) {
1433	>	@SuppressWarnings("unchecked")
1434	>	K k = (K) s.readObject();
1435	>	@SuppressWarnings("unchecked")
1436	>	V v = (V) s.readObject();
1437	>	if (k != null && v != null) {
1438	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1439	>	++size;
1440	>	}
1441	>	else
1442	>	break;
1443	>	}
1444	>	if (size == 0L)
1445	>	sizeCtl = 0;
1446	>	else {
1447	>	int n;
1448	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1449	>	n = MAXIMUM_CAPACITY;
1450	>	else {
1451	>	int sz = (int)size;
1452	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1453	>	}
1454	>	@SuppressWarnings("unchecked")
1455	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1456	>	int mask = n - 1;
1457	>	long added = 0L;
1458	>	while (p != null) {
1459	>	boolean insertAtFront;
1460	>	Node<K,V> next = p.next, first;
1461	>	int h = p.hash, j = h & mask;
1462	>	if ((first = tabAt(tab, j)) == null)
1463	>	insertAtFront = true;
1464	>	else {
1465	>	K k = p.key;
1466	>	if (first.hash < 0) {
1467	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1468	>	if (t.putTreeVal(h, k, p.val) == null)
1469	>	++added;
1470	>	insertAtFront = false;
1471	>	}
1472	>	else {
1473	>	int binCount = 0;
1474	>	insertAtFront = true;
1475	>	Node<K,V> q; K qk;
1476	>	for (q = first; q != null; q = q.next) {
1477	>	if (q.hash == h &&
1478	>	((qk = q.key) == k ||
1479	>	(qk != null && k.equals(qk)))) {
1480	>	insertAtFront = false;
1481	>	break;
1482	>	}
1483	>	++binCount;
1484	>	}
1485	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1486	>	insertAtFront = false;
1487	>	++added;
1488	>	p.next = first;
1489	>	TreeNode<K,V> hd = null, tl = null;
1490	>	for (q = p; q != null; q = q.next) {
1491	>	TreeNode<K,V> t = new TreeNode<K,V>
1492	>	(q.hash, q.key, q.val, null, null);
1493	>	if ((t.prev = tl) == null)
1494	>	hd = t;
1495	>	else
1496	>	tl.next = t;
1497	>	tl = t;
1498	>	}
1499	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1500	>	}
1501	>	}
1502	>	}
1503	>	if (insertAtFront) {
1504	>	++added;
1505	>	p.next = first;
1506	>	setTabAt(tab, j, p);
1507	>	}
1508	>	p = next;
1509	>	}
1510	>	table = tab;
1511	>	sizeCtl = n - (n >>> 2);
1512	>	baseCount = added;
1513	>	}
1514		}
1515
1516	+	// ConcurrentMap methods
1517	+
1518		/**
1519	<	* 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
1519	>	* {@inheritDoc}
1520		*
1521	<	* @since 1.6
1521	>	* @return the previous value associated with the specified key,
1522	>	*         or {@code null} if there was no mapping for the key
1523	>	* @throws NullPointerException if the specified key or value is null
1524		*/
1525	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
1526	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1525	>	public V putIfAbsent(K key, V value) {
1526	>	return putVal(key, value, true);
1527		}
1528
1529		/**
1530	<	* Creates a new, empty map with the specified initial capacity,
632	<	* and with default load factor (0.75) and concurrencyLevel (16).
1530	>	* {@inheritDoc}
1531		*
1532	<	* @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.
1532	>	* @throws NullPointerException if the specified key is null
1533		*/
1534	<	public ConcurrentHashMap(int initialCapacity) {
1535	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1534	>	public boolean remove(Object key, Object value) {
1535	>	if (key == null)
1536	>	throw new NullPointerException();
1537	>	return value != null && replaceNode(key, null, value) != null;
1538		}
1539
1540		/**
1541	<	* Creates a new, empty map with a default initial capacity (16),
1542	<	* load factor (0.75) and concurrencyLevel (16).
1541	>	* {@inheritDoc}
1542	>	*
1543	>	* @throws NullPointerException if any of the arguments are null
1544		*/
1545	<	public ConcurrentHashMap() {
1546	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1545	>	public boolean replace(K key, V oldValue, V newValue) {
1546	>	if (key == null || oldValue == null || newValue == null)
1547	>	throw new NullPointerException();
1548	>	return replaceNode(key, newValue, oldValue) != null;
1549		}
1550
1551		/**
1552	<	* 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).
1552	>	* {@inheritDoc}
1553		*
1554	<	* @param m the map
1554	>	* @return the previous value associated with the specified key,
1555	>	*         or {@code null} if there was no mapping for the key
1556	>	* @throws NullPointerException if the specified key or value is null
1557		*/
1558	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
1559	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
1560	<	DEFAULT_INITIAL_CAPACITY),
1561	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
663	<	putAll(m);
1558	>	public V replace(K key, V value) {
1559	>	if (key == null || value == null)
1560	>	throw new NullPointerException();
1561	>	return replaceNode(key, value, null);
1562		}
1563
1564	+	// Overrides of JDK8+ Map extension method defaults
1565	+
1566		/**
1567	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
1567	>	* Returns the value to which the specified key is mapped, or the
1568	>	* given default value if this map contains no mapping for the
1569	>	* key.
1570		*
1571	<	* @return <tt>true</tt> if this map contains no key-value mappings
1571	>	* @param key the key whose associated value is to be returned
1572	>	* @param defaultValue the value to return if this map contains
1573	>	* no mapping for the given key
1574	>	* @return the mapping for the key, if present; else the default value
1575	>	* @throws NullPointerException if the specified key is null
1576		*/
1577	<	public boolean isEmpty() {
1578	<	final Segment<K,V>[] segments = this.segments;
1579	<	/*
1580	<	* We keep track of per-segment modCounts to avoid ABA
1581	<	* problems in which an element in one segment was added and
1582	<	* in another removed during traversal, in which case the
1583	<	* table was never actually empty at any point. Note the
1584	<	* similar use of modCounts in the size() and containsValue()
1585	<	* methods, which are the only other methods also susceptible
1586	<	* to ABA problems.
1587	<	*/
1588	<	int[] mc = new int[segments.length];
1589	<	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;
1577	>	public V getOrDefault(Object key, V defaultValue) {
1578	>	V v;
1579	>	return (v = get(key)) == null ? defaultValue : v;
1580	>	}
1581	>
1582	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1583	>	if (action == null) throw new NullPointerException();
1584	>	Node<K,V>[] t;
1585	>	if ((t = table) != null) {
1586	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1587	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1588	>	action.accept(p.key, p.val);
1589	>	}
1590		}
1591	<	// If mcsum happens to be zero, then we know we got a snapshot
1592	<	// before any modifications at all were made.  This is
1593	<	// probably common enough to bother tracking.
1594	<	if (mcsum != 0) {
1595	<	for (int i = 0; i < segments.length; ++i) {
1596	<	if (segments[i].count != 0 ||
1597	<	mc[i] != segments[i].modCount)
1598	<	return false;
1591	>	}
1592	>
1593	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1594	>	if (function == null) throw new NullPointerException();
1595	>	Node<K,V>[] t;
1596	>	if ((t = table) != null) {
1597	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1598	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1599	>	V oldValue = p.val;
1600	>	for (K key = p.key;;) {
1601	>	V newValue = function.apply(key, oldValue);
1602	>	if (newValue == null)
1603	>	throw new NullPointerException();
1604	>	if (replaceNode(key, newValue, oldValue) != null ||
1605	>	(oldValue = get(key)) == null)
1606	>	break;
1607	>	}
1608		}
1609		}
700	–	return true;
1610		}
1611
1612		/**
1613	<	* 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
1613	>	* Helper method for EntrySetView.removeIf.
1614		*/
1615	<	public int size() {
1616	<	final Segment<K,V>[] segments = this.segments;
1617	<	long sum = 0;
1618	<	long check = 0;
1619	<	int[] mc = new int[segments.length];
1620	<	// Try a few times to get accurate count. On failure due to
1621	<	// continuous async changes in table, resort to locking.
1622	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1623	<	check = 0;
1624	<	sum = 0;
1625	<	int mcsum = 0;
1626	<	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	<	}
1615	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1616	>	if (function == null) throw new NullPointerException();
1617	>	Node<K,V>[] t;
1618	>	boolean removed = false;
1619	>	if ((t = table) != null) {
1620	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1621	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1622	>	K k = p.key;
1623	>	V v = p.val;
1624	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1625	>	if (function.test(e) && replaceNode(k, null, v) != null)
1626	>	removed = true;
1627		}
734	–	if (check == sum)
735	–	break;
1628		}
1629	<	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;
1629	>	return removed;
1630		}
1631
1632		/**
1633	<	* 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
1633	>	* Helper method for ValuesView.removeIf.
1634		*/
1635	<	public V get(Object key) {
1636	<	int hash = hash(key); // throws NullPointerException if key null
1637	<	return segmentFor(hash).get(key, hash);
1635	>	boolean removeValueIf(Predicate<? super V> function) {
1636	>	if (function == null) throw new NullPointerException();
1637	>	Node<K,V>[] t;
1638	>	boolean removed = false;
1639	>	if ((t = table) != null) {
1640	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1641	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1642	>	K k = p.key;
1643	>	V v = p.val;
1644	>	if (function.test(v) && replaceNode(k, null, v) != null)
1645	>	removed = true;
1646	>	}
1647	>	}
1648	>	return removed;
1649		}
1650
1651		/**
1652	<	* Tests if the specified object is a key in this table.
1652	>	* If the specified key is not already associated with a value,
1653	>	* attempts to compute its value using the given mapping function
1654	>	* and enters it into this map unless {@code null}.  The entire
1655	>	* method invocation is performed atomically, so the function is
1656	>	* applied at most once per key.  Some attempted update operations
1657	>	* on this map by other threads may be blocked while computation
1658	>	* is in progress, so the computation should be short and simple,
1659	>	* and must not attempt to update any other mappings of this map.
1660		*
1661	<	* @param  key   possible key
1662	<	* @return <tt>true</tt> if and only if the specified object
1663	<	*         is a key in this table, as determined by the
1664	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
1665	<	* @throws NullPointerException if the specified key is null
1661	>	* @param key key with which the specified value is to be associated
1662	>	* @param mappingFunction the function to compute a value
1663	>	* @return the current (existing or computed) value associated with
1664	>	*         the specified key, or null if the computed value is null
1665	>	* @throws NullPointerException if the specified key or mappingFunction
1666	>	*         is null
1667	>	* @throws IllegalStateException if the computation detectably
1668	>	*         attempts a recursive update to this map that would
1669	>	*         otherwise never complete
1670	>	* @throws RuntimeException or Error if the mappingFunction does so,
1671	>	*         in which case the mapping is left unestablished
1672		*/
1673	<	public boolean containsKey(Object key) {
1674	<	int hash = hash(key); // throws NullPointerException if key null
1675	<	return segmentFor(hash).containsKey(key, hash);
1673	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1674	>	if (key == null || mappingFunction == null)
1675	>	throw new NullPointerException();
1676	>	int h = spread(key.hashCode());
1677	>	V val = null;
1678	>	int binCount = 0;
1679	>	for (Node<K,V>[] tab = table;;) {
1680	>	Node<K,V> f; int n, i, fh; K fk; V fv;
1681	>	if (tab == null || (n = tab.length) == 0)
1682	>	tab = initTable();
1683	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1684	>	Node<K,V> r = new ReservationNode<K,V>();
1685	>	synchronized (r) {
1686	>	if (casTabAt(tab, i, null, r)) {
1687	>	binCount = 1;
1688	>	Node<K,V> node = null;
1689	>	try {
1690	>	if ((val = mappingFunction.apply(key)) != null)
1691	>	node = new Node<K,V>(h, key, val);
1692	>	} finally {
1693	>	setTabAt(tab, i, node);
1694	>	}
1695	>	}
1696	>	}
1697	>	if (binCount != 0)
1698	>	break;
1699	>	}
1700	>	else if ((fh = f.hash) == MOVED)
1701	>	tab = helpTransfer(tab, f);
1702	>	else if (fh == h    // check first node without acquiring lock
1703	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
1704	>	&& (fv = f.val) != null)
1705	>	return fv;
1706	>	else {
1707	>	boolean added = false;
1708	>	synchronized (f) {
1709	>	if (tabAt(tab, i) == f) {
1710	>	if (fh >= 0) {
1711	>	binCount = 1;
1712	>	for (Node<K,V> e = f;; ++binCount) {
1713	>	K ek;
1714	>	if (e.hash == h &&
1715	>	((ek = e.key) == key ||
1716	>	(ek != null && key.equals(ek)))) {
1717	>	val = e.val;
1718	>	break;
1719	>	}
1720	>	Node<K,V> pred = e;
1721	>	if ((e = e.next) == null) {
1722	>	if ((val = mappingFunction.apply(key)) != null) {
1723	>	if (pred.next != null)
1724	>	throw new IllegalStateException("Recursive update");
1725	>	added = true;
1726	>	pred.next = new Node<K,V>(h, key, val);
1727	>	}
1728	>	break;
1729	>	}
1730	>	}
1731	>	}
1732	>	else if (f instanceof TreeBin) {
1733	>	binCount = 2;
1734	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1735	>	TreeNode<K,V> r, p;
1736	>	if ((r = t.root) != null &&
1737	>	(p = r.findTreeNode(h, key, null)) != null)
1738	>	val = p.val;
1739	>	else if ((val = mappingFunction.apply(key)) != null) {
1740	>	added = true;
1741	>	t.putTreeVal(h, key, val);
1742	>	}
1743	>	}
1744	>	else if (f instanceof ReservationNode)
1745	>	throw new IllegalStateException("Recursive update");
1746	>	}
1747	>	}
1748	>	if (binCount != 0) {
1749	>	if (binCount >= TREEIFY_THRESHOLD)
1750	>	treeifyBin(tab, i);
1751	>	if (!added)
1752	>	return val;
1753	>	break;
1754	>	}
1755	>	}
1756	>	}
1757	>	if (val != null)
1758	>	addCount(1L, binCount);
1759	>	return val;
1760		}
1761
1762		/**
1763	<	* Returns <tt>true</tt> if this map maps one or more keys to the
1764	<	* specified value. Note: This method requires a full internal
1765	<	* traversal of the hash table, and so is much slower than
1766	<	* method <tt>containsKey</tt>.
1763	>	* If the value for the specified key is present, attempts to
1764	>	* compute a new mapping given the key and its current mapped
1765	>	* value.  The entire method invocation is performed atomically.
1766	>	* Some attempted update operations on this map by other threads
1767	>	* may be blocked while computation is in progress, so the
1768	>	* computation should be short and simple, and must not attempt to
1769	>	* update any other mappings of this map.
1770		*
1771	<	* @param value value whose presence in this map is to be tested
1772	<	* @return <tt>true</tt> if this map maps one or more keys to the
1773	<	*         specified value
1774	<	* @throws NullPointerException if the specified value is null
1771	>	* @param key key with which a value may be associated
1772	>	* @param remappingFunction the function to compute a value
1773	>	* @return the new value associated with the specified key, or null if none
1774	>	* @throws NullPointerException if the specified key or remappingFunction
1775	>	*         is null
1776	>	* @throws IllegalStateException if the computation detectably
1777	>	*         attempts a recursive update to this map that would
1778	>	*         otherwise never complete
1779	>	* @throws RuntimeException or Error if the remappingFunction does so,
1780	>	*         in which case the mapping is unchanged
1781		*/
1782	<	public boolean containsValue(Object value) {
1783	<	if (value == null)
1782	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1783	>	if (key == null || remappingFunction == null)
1784		throw new NullPointerException();
1785	+	int h = spread(key.hashCode());
1786	+	V val = null;
1787	+	int delta = 0;
1788	+	int binCount = 0;
1789	+	for (Node<K,V>[] tab = table;;) {
1790	+	Node<K,V> f; int n, i, fh;
1791	+	if (tab == null || (n = tab.length) == 0)
1792	+	tab = initTable();
1793	+	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1794	+	break;
1795	+	else if ((fh = f.hash) == MOVED)
1796	+	tab = helpTransfer(tab, f);
1797	+	else {
1798	+	synchronized (f) {
1799	+	if (tabAt(tab, i) == f) {
1800	+	if (fh >= 0) {
1801	+	binCount = 1;
1802	+	for (Node<K,V> e = f, pred = null;; ++binCount) {
1803	+	K ek;
1804	+	if (e.hash == h &&
1805	+	((ek = e.key) == key ||
1806	+	(ek != null && key.equals(ek)))) {
1807	+	val = remappingFunction.apply(key, e.val);
1808	+	if (val != null)
1809	+	e.val = val;
1810	+	else {
1811	+	delta = -1;
1812	+	Node<K,V> en = e.next;
1813	+	if (pred != null)
1814	+	pred.next = en;
1815	+	else
1816	+	setTabAt(tab, i, en);
1817	+	}
1818	+	break;
1819	+	}
1820	+	pred = e;
1821	+	if ((e = e.next) == null)
1822	+	break;
1823	+	}
1824	+	}
1825	+	else if (f instanceof TreeBin) {
1826	+	binCount = 2;
1827	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
1828	+	TreeNode<K,V> r, p;
1829	+	if ((r = t.root) != null &&
1830	+	(p = r.findTreeNode(h, key, null)) != null) {
1831	+	val = remappingFunction.apply(key, p.val);
1832	+	if (val != null)
1833	+	p.val = val;
1834	+	else {
1835	+	delta = -1;
1836	+	if (t.removeTreeNode(p))
1837	+	setTabAt(tab, i, untreeify(t.first));
1838	+	}
1839	+	}
1840	+	}
1841	+	else if (f instanceof ReservationNode)
1842	+	throw new IllegalStateException("Recursive update");
1843	+	}
1844	+	}
1845	+	if (binCount != 0)
1846	+	break;
1847	+	}
1848	+	}
1849	+	if (delta != 0)
1850	+	addCount((long)delta, binCount);
1851	+	return val;
1852	+	}
1853
1854	<	// See explanation of modCount use above
1855	<
1856	<	final Segment<K,V>[] segments = this.segments;
1857	<	int[] mc = new int[segments.length];
1858	<
1859	<	// Try a few times without locking
1860	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1861	<	int sum = 0;
1862	<	int mcsum = 0;
1863	<	for (int i = 0; i < segments.length; ++i) {
1864	<	int c = segments[i].count;
1865	<	mcsum += mc[i] = segments[i].modCount;
1866	<	if (segments[i].containsValue(value))
1867	<	return true;
1854	>	/**
1855	>	* Attempts to compute a mapping for the specified key and its
1856	>	* current mapped value (or {@code null} if there is no current
1857	>	* mapping). The entire method invocation is performed atomically.
1858	>	* Some attempted update operations on this map by other threads
1859	>	* may be blocked while computation is in progress, so the
1860	>	* computation should be short and simple, and must not attempt to
1861	>	* update any other mappings of this Map.
1862	>	*
1863	>	* @param key key with which the specified value is to be associated
1864	>	* @param remappingFunction the function to compute a value
1865	>	* @return the new value associated with the specified key, or null if none
1866	>	* @throws NullPointerException if the specified key or remappingFunction
1867	>	*         is null
1868	>	* @throws IllegalStateException if the computation detectably
1869	>	*         attempts a recursive update to this map that would
1870	>	*         otherwise never complete
1871	>	* @throws RuntimeException or Error if the remappingFunction does so,
1872	>	*         in which case the mapping is unchanged
1873	>	*/
1874	>	public V compute(K key,
1875	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1876	>	if (key == null || remappingFunction == null)
1877	>	throw new NullPointerException();
1878	>	int h = spread(key.hashCode());
1879	>	V val = null;
1880	>	int delta = 0;
1881	>	int binCount = 0;
1882	>	for (Node<K,V>[] tab = table;;) {
1883	>	Node<K,V> f; int n, i, fh;
1884	>	if (tab == null || (n = tab.length) == 0)
1885	>	tab = initTable();
1886	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1887	>	Node<K,V> r = new ReservationNode<K,V>();
1888	>	synchronized (r) {
1889	>	if (casTabAt(tab, i, null, r)) {
1890	>	binCount = 1;
1891	>	Node<K,V> node = null;
1892	>	try {
1893	>	if ((val = remappingFunction.apply(key, null)) != null) {
1894	>	delta = 1;
1895	>	node = new Node<K,V>(h, key, val);
1896	>	}
1897	>	} finally {
1898	>	setTabAt(tab, i, node);
1899	>	}
1900	>	}
1901	>	}
1902	>	if (binCount != 0)
1903	>	break;
1904		}
1905	<	boolean cleanSweep = true;
1906	<	if (mcsum != 0) {
1907	<	for (int i = 0; i < segments.length; ++i) {
1908	<	int c = segments[i].count;
1909	<	if (mc[i] != segments[i].modCount) {
1910	<	cleanSweep = false;
1911	<	break;
1905	>	else if ((fh = f.hash) == MOVED)
1906	>	tab = helpTransfer(tab, f);
1907	>	else {
1908	>	synchronized (f) {
1909	>	if (tabAt(tab, i) == f) {
1910	>	if (fh >= 0) {
1911	>	binCount = 1;
1912	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1913	>	K ek;
1914	>	if (e.hash == h &&
1915	>	((ek = e.key) == key ||
1916	>	(ek != null && key.equals(ek)))) {
1917	>	val = remappingFunction.apply(key, e.val);
1918	>	if (val != null)
1919	>	e.val = val;
1920	>	else {
1921	>	delta = -1;
1922	>	Node<K,V> en = e.next;
1923	>	if (pred != null)
1924	>	pred.next = en;
1925	>	else
1926	>	setTabAt(tab, i, en);
1927	>	}
1928	>	break;
1929	>	}
1930	>	pred = e;
1931	>	if ((e = e.next) == null) {
1932	>	val = remappingFunction.apply(key, null);
1933	>	if (val != null) {
1934	>	if (pred.next != null)
1935	>	throw new IllegalStateException("Recursive update");
1936	>	delta = 1;
1937	>	pred.next = new Node<K,V>(h, key, val);
1938	>	}
1939	>	break;
1940	>	}
1941	>	}
1942	>	}
1943	>	else if (f instanceof TreeBin) {
1944	>	binCount = 1;
1945	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1946	>	TreeNode<K,V> r, p;
1947	>	if ((r = t.root) != null)
1948	>	p = r.findTreeNode(h, key, null);
1949	>	else
1950	>	p = null;
1951	>	V pv = (p == null) ? null : p.val;
1952	>	val = remappingFunction.apply(key, pv);
1953	>	if (val != null) {
1954	>	if (p != null)
1955	>	p.val = val;
1956	>	else {
1957	>	delta = 1;
1958	>	t.putTreeVal(h, key, val);
1959	>	}
1960	>	}
1961	>	else if (p != null) {
1962	>	delta = -1;
1963	>	if (t.removeTreeNode(p))
1964	>	setTabAt(tab, i, untreeify(t.first));
1965	>	}
1966	>	}
1967	>	else if (f instanceof ReservationNode)
1968	>	throw new IllegalStateException("Recursive update");
1969		}
1970		}
1971	+	if (binCount != 0) {
1972	+	if (binCount >= TREEIFY_THRESHOLD)
1973	+	treeifyBin(tab, i);
1974	+	break;
1975	+	}
1976		}
820	–	if (cleanSweep)
821	–	return false;
1977		}
1978	<	// Resort to locking all segments
1979	<	for (int i = 0; i < segments.length; ++i)
1980	<	segments[i].lock();
1981	<	boolean found = false;
1982	<	try {
1983	<	for (int i = 0; i < segments.length; ++i) {
1984	<	if (segments[i].containsValue(value)) {
1985	<	found = true;
1978	>	if (delta != 0)
1979	>	addCount((long)delta, binCount);
1980	>	return val;
1981	>	}
1982	>
1983	>	/**
1984	>	* If the specified key is not already associated with a
1985	>	* (non-null) value, associates it with the given value.
1986	>	* Otherwise, replaces the value with the results of the given
1987	>	* remapping function, or removes if {@code null}. The entire
1988	>	* method invocation is performed atomically.  Some attempted
1989	>	* update operations on this map by other threads may be blocked
1990	>	* while computation is in progress, so the computation should be
1991	>	* short and simple, and must not attempt to update any other
1992	>	* mappings of this Map.
1993	>	*
1994	>	* @param key key with which the specified value is to be associated
1995	>	* @param value the value to use if absent
1996	>	* @param remappingFunction the function to recompute a value if present
1997	>	* @return the new value associated with the specified key, or null if none
1998	>	* @throws NullPointerException if the specified key or the
1999	>	*         remappingFunction is null
2000	>	* @throws RuntimeException or Error if the remappingFunction does so,
2001	>	*         in which case the mapping is unchanged
2002	>	*/
2003	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2004	>	if (key == null || value == null || remappingFunction == null)
2005	>	throw new NullPointerException();
2006	>	int h = spread(key.hashCode());
2007	>	V val = null;
2008	>	int delta = 0;
2009	>	int binCount = 0;
2010	>	for (Node<K,V>[] tab = table;;) {
2011	>	Node<K,V> f; int n, i, fh;
2012	>	if (tab == null || (n = tab.length) == 0)
2013	>	tab = initTable();
2014	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
2015	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value))) {
2016	>	delta = 1;
2017	>	val = value;
2018	>	break;
2019	>	}
2020	>	}
2021	>	else if ((fh = f.hash) == MOVED)
2022	>	tab = helpTransfer(tab, f);
2023	>	else {
2024	>	synchronized (f) {
2025	>	if (tabAt(tab, i) == f) {
2026	>	if (fh >= 0) {
2027	>	binCount = 1;
2028	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2029	>	K ek;
2030	>	if (e.hash == h &&
2031	>	((ek = e.key) == key ||
2032	>	(ek != null && key.equals(ek)))) {
2033	>	val = remappingFunction.apply(e.val, value);
2034	>	if (val != null)
2035	>	e.val = val;
2036	>	else {
2037	>	delta = -1;
2038	>	Node<K,V> en = e.next;
2039	>	if (pred != null)
2040	>	pred.next = en;
2041	>	else
2042	>	setTabAt(tab, i, en);
2043	>	}
2044	>	break;
2045	>	}
2046	>	pred = e;
2047	>	if ((e = e.next) == null) {
2048	>	delta = 1;
2049	>	val = value;
2050	>	pred.next = new Node<K,V>(h, key, val);
2051	>	break;
2052	>	}
2053	>	}
2054	>	}
2055	>	else if (f instanceof TreeBin) {
2056	>	binCount = 2;
2057	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2058	>	TreeNode<K,V> r = t.root;
2059	>	TreeNode<K,V> p = (r == null) ? null :
2060	>	r.findTreeNode(h, key, null);
2061	>	val = (p == null) ? value :
2062	>	remappingFunction.apply(p.val, value);
2063	>	if (val != null) {
2064	>	if (p != null)
2065	>	p.val = val;
2066	>	else {
2067	>	delta = 1;
2068	>	t.putTreeVal(h, key, val);
2069	>	}
2070	>	}
2071	>	else if (p != null) {
2072	>	delta = -1;
2073	>	if (t.removeTreeNode(p))
2074	>	setTabAt(tab, i, untreeify(t.first));
2075	>	}
2076	>	}
2077	>	else if (f instanceof ReservationNode)
2078	>	throw new IllegalStateException("Recursive update");
2079	>	}
2080	>	}
2081	>	if (binCount != 0) {
2082	>	if (binCount >= TREEIFY_THRESHOLD)
2083	>	treeifyBin(tab, i);
2084		break;
2085		}
2086		}
834	–	} finally {
835	–	for (int i = 0; i < segments.length; ++i)
836	–	segments[i].unlock();
2087		}
2088	<	return found;
2088	>	if (delta != 0)
2089	>	addCount((long)delta, binCount);
2090	>	return val;
2091		}
2092
2093	+	// Hashtable legacy methods
2094	+
2095		/**
2096	<	* Legacy method testing if some key maps into the specified value
2097	<	* in this table.  This method is identical in functionality to
2098	<	* {@link #containsValue}, and exists solely to ensure
2096	>	* Tests if some key maps into the specified value in this table.
2097	>	*
2098	>	* <p>Note that this method is identical in functionality to
2099	>	* {@link #containsValue(Object)}, and exists solely to ensure
2100		* full compatibility with class {@link java.util.Hashtable},
2101		* which supported this method prior to introduction of the
2102	<	* Java Collections framework.
2103	<
2102	>	* Java Collections Framework.
2103	>	*
2104		* @param  value a value to search for
2105	<	* @return <tt>true</tt> if and only if some key maps to the
2106	<	*         <tt>value</tt> argument in this table as
2107	<	*         determined by the <tt>equals</tt> method;
2108	<	*         <tt>false</tt> otherwise
2105	>	* @return {@code true} if and only if some key maps to the
2106	>	*         {@code value} argument in this table as
2107	>	*         determined by the {@code equals} method;
2108	>	*         {@code false} otherwise
2109		* @throws NullPointerException if the specified value is null
2110		*/
2111		public boolean contains(Object value) {
#	Line 858 | Line 2113 | public class ConcurrentHashMap<K, V> ext
2113		}
2114
2115		/**
2116	<	* 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.
2116	>	* Returns an enumeration of the keys in this table.
2117		*
2118	<	* @param key key with which the specified value is to be associated
2119	<	* @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
2118	>	* @return an enumeration of the keys in this table
2119	>	* @see #keySet()
2120		*/
2121	<	public V put(K key, V value) {
2122	<	if (value == null)
2123	<	throw new NullPointerException();
2124	<	int hash = hash(key);
877	<	return segmentFor(hash).put(key, hash, value, false);
2121	>	public Enumeration<K> keys() {
2122	>	Node<K,V>[] t;
2123	>	int f = (t = table) == null ? 0 : t.length;
2124	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2125		}
2126
2127		/**
2128	<	* {@inheritDoc}
2128	>	* Returns an enumeration of the values in this table.
2129		*
2130	<	* @return the previous value associated with the specified key,
2131	<	*         or <tt>null</tt> if there was no mapping for the key
885	<	* @throws NullPointerException if the specified key or value is null
2130	>	* @return an enumeration of the values in this table
2131	>	* @see #values()
2132		*/
2133	<	public V putIfAbsent(K key, V value) {
2134	<	if (value == null)
2135	<	throw new NullPointerException();
2136	<	int hash = hash(key);
891	<	return segmentFor(hash).put(key, hash, value, true);
2133	>	public Enumeration<V> elements() {
2134	>	Node<K,V>[] t;
2135	>	int f = (t = table) == null ? 0 : t.length;
2136	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2137		}
2138
2139	+	// ConcurrentHashMap-only methods
2140	+
2141		/**
2142	<	* Copies all of the mappings from the specified map to this one.
2143	<	* These mappings replace any mappings that this map had for any of the
2144	<	* keys currently in the specified map.
2142	>	* Returns the number of mappings. This method should be used
2143	>	* instead of {@link #size} because a ConcurrentHashMap may
2144	>	* contain more mappings than can be represented as an int. The
2145	>	* value returned is an estimate; the actual count may differ if
2146	>	* there are concurrent insertions or removals.
2147		*
2148	<	* @param m mappings to be stored in this map
2148	>	* @return the number of mappings
2149	>	* @since 1.8
2150		*/
2151	<	public void putAll(Map<? extends K, ? extends V> m) {
2152	<	for (Iterator<? extends Map.Entry<? extends K, ? extends V>> it = (Iterator<? extends Map.Entry<? extends K, ? extends V>>) m.entrySet().iterator(); it.hasNext(); ) {
2153	<	Entry<? extends K, ? extends V> e = it.next();
904	<	put(e.getKey(), e.getValue());
905	<	}
2151	>	public long mappingCount() {
2152	>	long n = sumCount();
2153	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2154		}
2155
2156		/**
2157	<	* Removes the key (and its corresponding value) from this map.
2158	<	* This method does nothing if the key is not in the map.
2157	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2158	>	* from the given type to {@code Boolean.TRUE}.
2159		*
2160	<	* @param  key the key that needs to be removed
2161	<	* @return the previous value associated with <tt>key</tt>, or
2162	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>.
2163	<	* @throws NullPointerException if the specified key is null
2164	<	*/
2165	<	public V remove(Object key) {
2166	<	int hash = hash(key);
919	<	return segmentFor(hash).remove(key, hash, null);
2160	>	* @param <K> the element type of the returned set
2161	>	* @return the new set
2162	>	* @since 1.8
2163	>	*/
2164	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2165	>	return new KeySetView<K,Boolean>
2166	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2167		}
2168
2169		/**
2170	<	* {@inheritDoc}
2170	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2171	>	* from the given type to {@code Boolean.TRUE}.
2172		*
2173	<	* @throws NullPointerException if the specified key is null
2173	>	* @param initialCapacity The implementation performs internal
2174	>	* sizing to accommodate this many elements.
2175	>	* @param <K> the element type of the returned set
2176	>	* @return the new set
2177	>	* @throws IllegalArgumentException if the initial capacity of
2178	>	* elements is negative
2179	>	* @since 1.8
2180		*/
2181	<	public boolean remove(Object key, Object value) {
2182	<	if (value == null)
2183	<	return false;
930	<	int hash = hash(key);
931	<	return segmentFor(hash).remove(key, hash, value) != null;
2181	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2182	>	return new KeySetView<K,Boolean>
2183	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2184		}
2185
2186		/**
2187	<	* {@inheritDoc}
2187	>	* Returns a {@link Set} view of the keys in this map, using the
2188	>	* given common mapped value for any additions (i.e., {@link
2189	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2190	>	* This is of course only appropriate if it is acceptable to use
2191	>	* the same value for all additions from this view.
2192		*
2193	<	* @throws NullPointerException if any of the arguments are null
2193	>	* @param mappedValue the mapped value to use for any additions
2194	>	* @return the set view
2195	>	* @throws NullPointerException if the mappedValue is null
2196		*/
2197	<	public boolean replace(K key, V oldValue, V newValue) {
2198	<	if (oldValue == null || newValue == null)
2197	>	public KeySetView<K,V> keySet(V mappedValue) {
2198	>	if (mappedValue == null)
2199		throw new NullPointerException();
2200	<	int hash = hash(key);
943	<	return segmentFor(hash).replace(key, hash, oldValue, newValue);
2200	>	return new KeySetView<K,V>(this, mappedValue);
2201		}
2202
2203	+	/* ---------------- Special Nodes -------------- */
2204	+
2205		/**
2206	<	* {@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
2206	>	* A node inserted at head of bins during transfer operations.
2207		*/
2208	<	public V replace(K key, V value) {
2209	<	if (value == null)
2210	<	throw new NullPointerException();
2211	<	int hash = hash(key);
2212	<	return segmentFor(hash).replace(key, hash, value);
2208	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2209	>	final Node<K,V>[] nextTable;
2210	>	ForwardingNode(Node<K,V>[] tab) {
2211	>	super(MOVED, null, null);
2212	>	this.nextTable = tab;
2213	>	}
2214	>
2215	>	Node<K,V> find(int h, Object k) {
2216	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2217	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2218	>	Node<K,V> e; int n;
2219	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2220	>	(e = tabAt(tab, (n - 1) & h)) == null)
2221	>	return null;
2222	>	for (;;) {
2223	>	int eh; K ek;
2224	>	if ((eh = e.hash) == h &&
2225	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2226	>	return e;
2227	>	if (eh < 0) {
2228	>	if (e instanceof ForwardingNode) {
2229	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2230	>	continue outer;
2231	>	}
2232	>	else
2233	>	return e.find(h, k);
2234	>	}
2235	>	if ((e = e.next) == null)
2236	>	return null;
2237	>	}
2238	>	}
2239	>	}
2240		}
2241
2242		/**
2243	<	* Removes all of the mappings from this map.
2243	>	* A place-holder node used in computeIfAbsent and compute.
2244		*/
2245	<	public void clear() {
2246	<	for (int i = 0; i < segments.length; ++i)
2247	<	segments[i].clear();
2245	>	static final class ReservationNode<K,V> extends Node<K,V> {
2246	>	ReservationNode() {
2247	>	super(RESERVED, null, null);
2248	>	}
2249	>
2250	>	Node<K,V> find(int h, Object k) {
2251	>	return null;
2252	>	}
2253		}
2254
2255	+	/* ---------------- Table Initialization and Resizing -------------- */
2256	+
2257		/**
2258	<	* Returns a {@link Set} view of the keys contained in this map.
2259	<	* The set is backed by the map, so changes to the map are
2260	<	* reflected in the set, and vice-versa.  The set supports element
2261	<	* removal, which removes the corresponding mapping from this map,
2262	<	* 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());
2258	>	* Returns the stamp bits for resizing a table of size n.
2259	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2260	>	*/
2261	>	static final int resizeStamp(int n) {
2262	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2263		}
2264
2265		/**
2266	<	* 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.
2266	>	* Initializes table, using the size recorded in sizeCtl.
2267		*/
2268	<	public Collection<V> values() {
2269	<	Collection<V> vs = values;
2270	<	return (vs != null) ? vs : (values = new Values());
2268	>	private final Node<K,V>[] initTable() {
2269	>	Node<K,V>[] tab; int sc;
2270	>	while ((tab = table) == null || tab.length == 0) {
2271	>	if ((sc = sizeCtl) < 0)
2272	>	Thread.yield(); // lost initialization race; just spin
2273	>	else if (U.compareAndSetInt(this, SIZECTL, sc, -1)) {
2274	>	try {
2275	>	if ((tab = table) == null || tab.length == 0) {
2276	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2277	>	@SuppressWarnings("unchecked")
2278	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2279	>	table = tab = nt;
2280	>	sc = n - (n >>> 2);
2281	>	}
2282	>	} finally {
2283	>	sizeCtl = sc;
2284	>	}
2285	>	break;
2286	>	}
2287	>	}
2288	>	return tab;
2289		}
2290
2291		/**
2292	<	* Returns a {@link Set} view of the mappings contained in this map.
2293	<	* The set is backed by the map, so changes to the map are
2294	<	* reflected in the set, and vice-versa.  The set supports element
2295	<	* removal, which removes the corresponding mapping from the map,
2296	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2297	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2298	<	* operations.  It does not support the <tt>add</tt> or
2299	<	* <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.
2292	>	* Adds to count, and if table is too small and not already
2293	>	* resizing, initiates transfer. If already resizing, helps
2294	>	* perform transfer if work is available.  Rechecks occupancy
2295	>	* after a transfer to see if another resize is already needed
2296	>	* because resizings are lagging additions.
2297	>	*
2298	>	* @param x the count to add
2299	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2300		*/
2301	<	public Set<Map.Entry<K,V>> entrySet() {
2302	<	Set<Map.Entry<K,V>> es = entrySet;
2303	<	return (es != null) ? es : (entrySet = new EntrySet());
2301	>	private final void addCount(long x, int check) {
2302	>	CounterCell[] as; long b, s;
2303	>	if ((as = counterCells) != null ||
2304	>	!U.compareAndSetLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2305	>	CounterCell a; long v; int m;
2306	>	boolean uncontended = true;
2307	>	if (as == null || (m = as.length - 1) < 0 ||
2308	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2309	>	!(uncontended =
2310	>	U.compareAndSetLong(a, CELLVALUE, v = a.value, v + x))) {
2311	>	fullAddCount(x, uncontended);
2312	>	return;
2313	>	}
2314	>	if (check <= 1)
2315	>	return;
2316	>	s = sumCount();
2317	>	}
2318	>	if (check >= 0) {
2319	>	Node<K,V>[] tab, nt; int n, sc;
2320	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2321	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2322	>	int rs = resizeStamp(n);
2323	>	if (sc < 0) {
2324	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2325	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2326	>	transferIndex <= 0)
2327	>	break;
2328	>	if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1))
2329	>	transfer(tab, nt);
2330	>	}
2331	>	else if (U.compareAndSetInt(this, SIZECTL, sc,
2332	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2333	>	transfer(tab, null);
2334	>	s = sumCount();
2335	>	}
2336	>	}
2337		}
2338
2339		/**
2340	<	* Returns an enumeration of the keys in this table.
1033	<	*
1034	<	* @return an enumeration of the keys in this table
1035	<	* @see #keySet
2340	>	* Helps transfer if a resize is in progress.
2341		*/
2342	<	public Enumeration<K> keys() {
2343	<	return new KeyIterator();
2342	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2343	>	Node<K,V>[] nextTab; int sc;
2344	>	if (tab != null && (f instanceof ForwardingNode) &&
2345	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2346	>	int rs = resizeStamp(tab.length);
2347	>	while (nextTab == nextTable && table == tab &&
2348	>	(sc = sizeCtl) < 0) {
2349	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2350	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2351	>	break;
2352	>	if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1)) {
2353	>	transfer(tab, nextTab);
2354	>	break;
2355	>	}
2356	>	}
2357	>	return nextTab;
2358	>	}
2359	>	return table;
2360		}
2361
2362		/**
2363	<	* Returns an enumeration of the values in this table.
2363	>	* Tries to presize table to accommodate the given number of elements.
2364		*
2365	<	* @return an enumeration of the values in this table
1045	<	* @see #values
2365	>	* @param size number of elements (doesn't need to be perfectly accurate)
2366		*/
2367	<	public Enumeration<V> elements() {
2368	<	return new ValueIterator();
2367	>	private final void tryPresize(int size) {
2368	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2369	>	tableSizeFor(size + (size >>> 1) + 1);
2370	>	int sc;
2371	>	while ((sc = sizeCtl) >= 0) {
2372	>	Node<K,V>[] tab = table; int n;
2373	>	if (tab == null || (n = tab.length) == 0) {
2374	>	n = (sc > c) ? sc : c;
2375	>	if (U.compareAndSetInt(this, SIZECTL, sc, -1)) {
2376	>	try {
2377	>	if (table == tab) {
2378	>	@SuppressWarnings("unchecked")
2379	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2380	>	table = nt;
2381	>	sc = n - (n >>> 2);
2382	>	}
2383	>	} finally {
2384	>	sizeCtl = sc;
2385	>	}
2386	>	}
2387	>	}
2388	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2389	>	break;
2390	>	else if (tab == table) {
2391	>	int rs = resizeStamp(n);
2392	>	if (U.compareAndSetInt(this, SIZECTL, sc,
2393	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2394	>	transfer(tab, null);
2395	>	}
2396	>	}
2397	>	}
2398	>
2399	>	/**
2400	>	* Moves and/or copies the nodes in each bin to new table. See
2401	>	* above for explanation.
2402	>	*/
2403	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2404	>	int n = tab.length, stride;
2405	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2406	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2407	>	if (nextTab == null) {            // initiating
2408	>	try {
2409	>	@SuppressWarnings("unchecked")
2410	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2411	>	nextTab = nt;
2412	>	} catch (Throwable ex) {      // try to cope with OOME
2413	>	sizeCtl = Integer.MAX_VALUE;
2414	>	return;
2415	>	}
2416	>	nextTable = nextTab;
2417	>	transferIndex = n;
2418	>	}
2419	>	int nextn = nextTab.length;
2420	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2421	>	boolean advance = true;
2422	>	boolean finishing = false; // to ensure sweep before committing nextTab
2423	>	for (int i = 0, bound = 0;;) {
2424	>	Node<K,V> f; int fh;
2425	>	while (advance) {
2426	>	int nextIndex, nextBound;
2427	>	if (--i >= bound || finishing)
2428	>	advance = false;
2429	>	else if ((nextIndex = transferIndex) <= 0) {
2430	>	i = -1;
2431	>	advance = false;
2432	>	}
2433	>	else if (U.compareAndSetInt
2434	>	(this, TRANSFERINDEX, nextIndex,
2435	>	nextBound = (nextIndex > stride ?
2436	>	nextIndex - stride : 0))) {
2437	>	bound = nextBound;
2438	>	i = nextIndex - 1;
2439	>	advance = false;
2440	>	}
2441	>	}
2442	>	if (i < 0 || i >= n || i + n >= nextn) {
2443	>	int sc;
2444	>	if (finishing) {
2445	>	nextTable = null;
2446	>	table = nextTab;
2447	>	sizeCtl = (n << 1) - (n >>> 1);
2448	>	return;
2449	>	}
2450	>	if (U.compareAndSetInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2451	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2452	>	return;
2453	>	finishing = advance = true;
2454	>	i = n; // recheck before commit
2455	>	}
2456	>	}
2457	>	else if ((f = tabAt(tab, i)) == null)
2458	>	advance = casTabAt(tab, i, null, fwd);
2459	>	else if ((fh = f.hash) == MOVED)
2460	>	advance = true; // already processed
2461	>	else {
2462	>	synchronized (f) {
2463	>	if (tabAt(tab, i) == f) {
2464	>	Node<K,V> ln, hn;
2465	>	if (fh >= 0) {
2466	>	int runBit = fh & n;
2467	>	Node<K,V> lastRun = f;
2468	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2469	>	int b = p.hash & n;
2470	>	if (b != runBit) {
2471	>	runBit = b;
2472	>	lastRun = p;
2473	>	}
2474	>	}
2475	>	if (runBit == 0) {
2476	>	ln = lastRun;
2477	>	hn = null;
2478	>	}
2479	>	else {
2480	>	hn = lastRun;
2481	>	ln = null;
2482	>	}
2483	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2484	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2485	>	if ((ph & n) == 0)
2486	>	ln = new Node<K,V>(ph, pk, pv, ln);
2487	>	else
2488	>	hn = new Node<K,V>(ph, pk, pv, hn);
2489	>	}
2490	>	setTabAt(nextTab, i, ln);
2491	>	setTabAt(nextTab, i + n, hn);
2492	>	setTabAt(tab, i, fwd);
2493	>	advance = true;
2494	>	}
2495	>	else if (f instanceof TreeBin) {
2496	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2497	>	TreeNode<K,V> lo = null, loTail = null;
2498	>	TreeNode<K,V> hi = null, hiTail = null;
2499	>	int lc = 0, hc = 0;
2500	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2501	>	int h = e.hash;
2502	>	TreeNode<K,V> p = new TreeNode<K,V>
2503	>	(h, e.key, e.val, null, null);
2504	>	if ((h & n) == 0) {
2505	>	if ((p.prev = loTail) == null)
2506	>	lo = p;
2507	>	else
2508	>	loTail.next = p;
2509	>	loTail = p;
2510	>	++lc;
2511	>	}
2512	>	else {
2513	>	if ((p.prev = hiTail) == null)
2514	>	hi = p;
2515	>	else
2516	>	hiTail.next = p;
2517	>	hiTail = p;
2518	>	++hc;
2519	>	}
2520	>	}
2521	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2522	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2523	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2524	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2525	>	setTabAt(nextTab, i, ln);
2526	>	setTabAt(nextTab, i + n, hn);
2527	>	setTabAt(tab, i, fwd);
2528	>	advance = true;
2529	>	}
2530	>	}
2531	>	}
2532	>	}
2533	>	}
2534		}
2535
2536	<	/* ---------------- Iterator Support -------------- */
2536	>	/* ---------------- Counter support -------------- */
2537
2538	<	abstract class HashIterator {
2539	<	int nextSegmentIndex;
2540	<	int nextTableIndex;
2541	<	HashEntry<K,V>[] currentTable;
2542	<	HashEntry<K, V> nextEntry;
2543	<	HashEntry<K, V> lastReturned;
2538	>	/**
2539	>	* A padded cell for distributing counts.  Adapted from LongAdder
2540	>	* and Striped64.  See their internal docs for explanation.
2541	>	*/
2542	>	@jdk.internal.vm.annotation.Contended static final class CounterCell {
2543	>	volatile long value;
2544	>	CounterCell(long x) { value = x; }
2545	>	}
2546
2547	<	HashIterator() {
2548	<	nextSegmentIndex = segments.length - 1;
2549	<	nextTableIndex = -1;
2550	<	advance();
2547	>	final long sumCount() {
2548	>	CounterCell[] as = counterCells; CounterCell a;
2549	>	long sum = baseCount;
2550	>	if (as != null) {
2551	>	for (int i = 0; i < as.length; ++i) {
2552	>	if ((a = as[i]) != null)
2553	>	sum += a.value;
2554	>	}
2555		}
2556	+	return sum;
2557	+	}
2558
2559	<	public boolean hasMoreElements() { return hasNext(); }
2559	>	// See LongAdder version for explanation
2560	>	private final void fullAddCount(long x, boolean wasUncontended) {
2561	>	int h;
2562	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2563	>	ThreadLocalRandom.localInit();      // force initialization
2564	>	h = ThreadLocalRandom.getProbe();
2565	>	wasUncontended = true;
2566	>	}
2567	>	boolean collide = false;                // True if last slot nonempty
2568	>	for (;;) {
2569	>	CounterCell[] as; CounterCell a; int n; long v;
2570	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2571	>	if ((a = as[(n - 1) & h]) == null) {
2572	>	if (cellsBusy == 0) {            // Try to attach new Cell
2573	>	CounterCell r = new CounterCell(x); // Optimistic create
2574	>	if (cellsBusy == 0 &&
2575	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2576	>	boolean created = false;
2577	>	try {               // Recheck under lock
2578	>	CounterCell[] rs; int m, j;
2579	>	if ((rs = counterCells) != null &&
2580	>	(m = rs.length) > 0 &&
2581	>	rs[j = (m - 1) & h] == null) {
2582	>	rs[j] = r;
2583	>	created = true;
2584	>	}
2585	>	} finally {
2586	>	cellsBusy = 0;
2587	>	}
2588	>	if (created)
2589	>	break;
2590	>	continue;           // Slot is now non-empty
2591	>	}
2592	>	}
2593	>	collide = false;
2594	>	}
2595	>	else if (!wasUncontended)       // CAS already known to fail
2596	>	wasUncontended = true;      // Continue after rehash
2597	>	else if (U.compareAndSetLong(a, CELLVALUE, v = a.value, v + x))
2598	>	break;
2599	>	else if (counterCells != as || n >= NCPU)
2600	>	collide = false;            // At max size or stale
2601	>	else if (!collide)
2602	>	collide = true;
2603	>	else if (cellsBusy == 0 &&
2604	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2605	>	try {
2606	>	if (counterCells == as) // Expand table unless stale
2607	>	counterCells = Arrays.copyOf(as, n << 1);
2608	>	} finally {
2609	>	cellsBusy = 0;
2610	>	}
2611	>	collide = false;
2612	>	continue;                   // Retry with expanded table
2613	>	}
2614	>	h = ThreadLocalRandom.advanceProbe(h);
2615	>	}
2616	>	else if (cellsBusy == 0 && counterCells == as &&
2617	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2618	>	boolean init = false;
2619	>	try {                           // Initialize table
2620	>	if (counterCells == as) {
2621	>	CounterCell[] rs = new CounterCell[2];
2622	>	rs[h & 1] = new CounterCell(x);
2623	>	counterCells = rs;
2624	>	init = true;
2625	>	}
2626	>	} finally {
2627	>	cellsBusy = 0;
2628	>	}
2629	>	if (init)
2630	>	break;
2631	>	}
2632	>	else if (U.compareAndSetLong(this, BASECOUNT, v = baseCount, v + x))
2633	>	break;                          // Fall back on using base
2634	>	}
2635	>	}
2636
2637	<	final void advance() {
1069	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
1070	<	return;
2637	>	/* ---------------- Conversion from/to TreeBins -------------- */
2638
2639	<	while (nextTableIndex >= 0) {
2640	<	if ( (nextEntry = currentTable[nextTableIndex--]) != null)
2641	<	return;
2639	>	/**
2640	>	* Replaces all linked nodes in bin at given index unless table is
2641	>	* too small, in which case resizes instead.
2642	>	*/
2643	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2644	>	Node<K,V> b; int n;
2645	>	if (tab != null) {
2646	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2647	>	tryPresize(n << 1);
2648	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2649	>	synchronized (b) {
2650	>	if (tabAt(tab, index) == b) {
2651	>	TreeNode<K,V> hd = null, tl = null;
2652	>	for (Node<K,V> e = b; e != null; e = e.next) {
2653	>	TreeNode<K,V> p =
2654	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2655	>	null, null);
2656	>	if ((p.prev = tl) == null)
2657	>	hd = p;
2658	>	else
2659	>	tl.next = p;
2660	>	tl = p;
2661	>	}
2662	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2663	>	}
2664	>	}
2665		}
2666	+	}
2667	+	}
2668
2669	<	while (nextSegmentIndex >= 0) {
2670	<	Segment<K,V> seg = segments[nextSegmentIndex--];
2671	<	if (seg.count != 0) {
2672	<	currentTable = seg.table;
2673	<	for (int j = currentTable.length - 1; j >= 0; --j) {
2674	<	if ( (nextEntry = currentTable[j]) != null) {
2675	<	nextTableIndex = j - 1;
2676	<	return;
2669	>	/**
2670	>	* Returns a list of non-TreeNodes replacing those in given list.
2671	>	*/
2672	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2673	>	Node<K,V> hd = null, tl = null;
2674	>	for (Node<K,V> q = b; q != null; q = q.next) {
2675	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val);
2676	>	if (tl == null)
2677	>	hd = p;
2678	>	else
2679	>	tl.next = p;
2680	>	tl = p;
2681	>	}
2682	>	return hd;
2683	>	}
2684	>
2685	>	/* ---------------- TreeNodes -------------- */
2686	>
2687	>	/**
2688	>	* Nodes for use in TreeBins.
2689	>	*/
2690	>	static final class TreeNode<K,V> extends Node<K,V> {
2691	>	TreeNode<K,V> parent;  // red-black tree links
2692	>	TreeNode<K,V> left;
2693	>	TreeNode<K,V> right;
2694	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2695	>	boolean red;
2696	>
2697	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2698	>	TreeNode<K,V> parent) {
2699	>	super(hash, key, val, next);
2700	>	this.parent = parent;
2701	>	}
2702	>
2703	>	Node<K,V> find(int h, Object k) {
2704	>	return findTreeNode(h, k, null);
2705	>	}
2706	>
2707	>	/**
2708	>	* Returns the TreeNode (or null if not found) for the given key
2709	>	* starting at given root.
2710	>	*/
2711	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2712	>	if (k != null) {
2713	>	TreeNode<K,V> p = this;
2714	>	do {
2715	>	int ph, dir; K pk; TreeNode<K,V> q;
2716	>	TreeNode<K,V> pl = p.left, pr = p.right;
2717	>	if ((ph = p.hash) > h)
2718	>	p = pl;
2719	>	else if (ph < h)
2720	>	p = pr;
2721	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2722	>	return p;
2723	>	else if (pl == null)
2724	>	p = pr;
2725	>	else if (pr == null)
2726	>	p = pl;
2727	>	else if ((kc != null ||
2728	>	(kc = comparableClassFor(k)) != null) &&
2729	>	(dir = compareComparables(kc, k, pk)) != 0)
2730	>	p = (dir < 0) ? pl : pr;
2731	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2732	>	return q;
2733	>	else
2734	>	p = pl;
2735	>	} while (p != null);
2736	>	}
2737	>	return null;
2738	>	}
2739	>	}
2740	>
2741	>	/* ---------------- TreeBins -------------- */
2742	>
2743	>	/**
2744	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2745	>	* keys or values, but instead point to list of TreeNodes and
2746	>	* their root. They also maintain a parasitic read-write lock
2747	>	* forcing writers (who hold bin lock) to wait for readers (who do
2748	>	* not) to complete before tree restructuring operations.
2749	>	*/
2750	>	static final class TreeBin<K,V> extends Node<K,V> {
2751	>	TreeNode<K,V> root;
2752	>	volatile TreeNode<K,V> first;
2753	>	volatile Thread waiter;
2754	>	volatile int lockState;
2755	>	// values for lockState
2756	>	static final int WRITER = 1; // set while holding write lock
2757	>	static final int WAITER = 2; // set when waiting for write lock
2758	>	static final int READER = 4; // increment value for setting read lock
2759	>
2760	>	/**
2761	>	* Tie-breaking utility for ordering insertions when equal
2762	>	* hashCodes and non-comparable. We don't require a total
2763	>	* order, just a consistent insertion rule to maintain
2764	>	* equivalence across rebalancings. Tie-breaking further than
2765	>	* necessary simplifies testing a bit.
2766	>	*/
2767	>	static int tieBreakOrder(Object a, Object b) {
2768	>	int d;
2769	>	if (a == null || b == null ||
2770	>	(d = a.getClass().getName().
2771	>	compareTo(b.getClass().getName())) == 0)
2772	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2773	>	-1 : 1);
2774	>	return d;
2775	>	}
2776	>
2777	>	/**
2778	>	* Creates bin with initial set of nodes headed by b.
2779	>	*/
2780	>	TreeBin(TreeNode<K,V> b) {
2781	>	super(TREEBIN, null, null);
2782	>	this.first = b;
2783	>	TreeNode<K,V> r = null;
2784	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2785	>	next = (TreeNode<K,V>)x.next;
2786	>	x.left = x.right = null;
2787	>	if (r == null) {
2788	>	x.parent = null;
2789	>	x.red = false;
2790	>	r = x;
2791	>	}
2792	>	else {
2793	>	K k = x.key;
2794	>	int h = x.hash;
2795	>	Class<?> kc = null;
2796	>	for (TreeNode<K,V> p = r;;) {
2797	>	int dir, ph;
2798	>	K pk = p.key;
2799	>	if ((ph = p.hash) > h)
2800	>	dir = -1;
2801	>	else if (ph < h)
2802	>	dir = 1;
2803	>	else if ((kc == null &&
2804	>	(kc = comparableClassFor(k)) == null) ||
2805	>	(dir = compareComparables(kc, k, pk)) == 0)
2806	>	dir = tieBreakOrder(k, pk);
2807	>	TreeNode<K,V> xp = p;
2808	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2809	>	x.parent = xp;
2810	>	if (dir <= 0)
2811	>	xp.left = x;
2812	>	else
2813	>	xp.right = x;
2814	>	r = balanceInsertion(r, x);
2815	>	break;
2816		}
2817		}
2818		}
2819		}
2820	+	this.root = r;
2821	+	assert checkInvariants(root);
2822		}
2823
2824	<	public boolean hasNext() { return nextEntry != null; }
2824	>	/**
2825	>	* Acquires write lock for tree restructuring.
2826	>	*/
2827	>	private final void lockRoot() {
2828	>	if (!U.compareAndSetInt(this, LOCKSTATE, 0, WRITER))
2829	>	contendedLock(); // offload to separate method
2830	>	}
2831
2832	<	HashEntry<K,V> nextEntry() {
2833	<	if (nextEntry == null)
2834	<	throw new NoSuchElementException();
2835	<	lastReturned = nextEntry;
2832	>	/**
2833	>	* Releases write lock for tree restructuring.
2834	>	*/
2835	>	private final void unlockRoot() {
2836	>	lockState = 0;
2837	>	}
2838	>
2839	>	/**
2840	>	* Possibly blocks awaiting root lock.
2841	>	*/
2842	>	private final void contendedLock() {
2843	>	boolean waiting = false;
2844	>	for (int s;;) {
2845	>	if (((s = lockState) & ~WAITER) == 0) {
2846	>	if (U.compareAndSetInt(this, LOCKSTATE, s, WRITER)) {
2847	>	if (waiting)
2848	>	waiter = null;
2849	>	return;
2850	>	}
2851	>	}
2852	>	else if ((s & WAITER) == 0) {
2853	>	if (U.compareAndSetInt(this, LOCKSTATE, s, s | WAITER)) {
2854	>	waiting = true;
2855	>	waiter = Thread.currentThread();
2856	>	}
2857	>	}
2858	>	else if (waiting)
2859	>	LockSupport.park(this);
2860	>	}
2861	>	}
2862	>
2863	>	/**
2864	>	* Returns matching node or null if none. Tries to search
2865	>	* using tree comparisons from root, but continues linear
2866	>	* search when lock not available.
2867	>	*/
2868	>	final Node<K,V> find(int h, Object k) {
2869	>	if (k != null) {
2870	>	for (Node<K,V> e = first; e != null; ) {
2871	>	int s; K ek;
2872	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2873	>	if (e.hash == h &&
2874	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2875	>	return e;
2876	>	e = e.next;
2877	>	}
2878	>	else if (U.compareAndSetInt(this, LOCKSTATE, s,
2879	>	s + READER)) {
2880	>	TreeNode<K,V> r, p;
2881	>	try {
2882	>	p = ((r = root) == null ? null :
2883	>	r.findTreeNode(h, k, null));
2884	>	} finally {
2885	>	Thread w;
2886	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2887	>	(READER|WAITER) && (w = waiter) != null)
2888	>	LockSupport.unpark(w);
2889	>	}
2890	>	return p;
2891	>	}
2892	>	}
2893	>	}
2894	>	return null;
2895	>	}
2896	>
2897	>	/**
2898	>	* Finds or adds a node.
2899	>	* @return null if added
2900	>	*/
2901	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2902	>	Class<?> kc = null;
2903	>	boolean searched = false;
2904	>	for (TreeNode<K,V> p = root;;) {
2905	>	int dir, ph; K pk;
2906	>	if (p == null) {
2907	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2908	>	break;
2909	>	}
2910	>	else if ((ph = p.hash) > h)
2911	>	dir = -1;
2912	>	else if (ph < h)
2913	>	dir = 1;
2914	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2915	>	return p;
2916	>	else if ((kc == null &&
2917	>	(kc = comparableClassFor(k)) == null) ||
2918	>	(dir = compareComparables(kc, k, pk)) == 0) {
2919	>	if (!searched) {
2920	>	TreeNode<K,V> q, ch;
2921	>	searched = true;
2922	>	if (((ch = p.left) != null &&
2923	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2924	>	((ch = p.right) != null &&
2925	>	(q = ch.findTreeNode(h, k, kc)) != null))
2926	>	return q;
2927	>	}
2928	>	dir = tieBreakOrder(k, pk);
2929	>	}
2930	>
2931	>	TreeNode<K,V> xp = p;
2932	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2933	>	TreeNode<K,V> x, f = first;
2934	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2935	>	if (f != null)
2936	>	f.prev = x;
2937	>	if (dir <= 0)
2938	>	xp.left = x;
2939	>	else
2940	>	xp.right = x;
2941	>	if (!xp.red)
2942	>	x.red = true;
2943	>	else {
2944	>	lockRoot();
2945	>	try {
2946	>	root = balanceInsertion(root, x);
2947	>	} finally {
2948	>	unlockRoot();
2949	>	}
2950	>	}
2951	>	break;
2952	>	}
2953	>	}
2954	>	assert checkInvariants(root);
2955	>	return null;
2956	>	}
2957	>
2958	>	/**
2959	>	* Removes the given node, that must be present before this
2960	>	* call.  This is messier than typical red-black deletion code
2961	>	* because we cannot swap the contents of an interior node
2962	>	* with a leaf successor that is pinned by "next" pointers
2963	>	* that are accessible independently of lock. So instead we
2964	>	* swap the tree linkages.
2965	>	*
2966	>	* @return true if now too small, so should be untreeified
2967	>	*/
2968	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2969	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2970	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2971	>	TreeNode<K,V> r, rl;
2972	>	if (pred == null)
2973	>	first = next;
2974	>	else
2975	>	pred.next = next;
2976	>	if (next != null)
2977	>	next.prev = pred;
2978	>	if (first == null) {
2979	>	root = null;
2980	>	return true;
2981	>	}
2982	>	if ((r = root) == null || r.right == null || // too small
2983	>	(rl = r.left) == null || rl.left == null)
2984	>	return true;
2985	>	lockRoot();
2986	>	try {
2987	>	TreeNode<K,V> replacement;
2988	>	TreeNode<K,V> pl = p.left;
2989	>	TreeNode<K,V> pr = p.right;
2990	>	if (pl != null && pr != null) {
2991	>	TreeNode<K,V> s = pr, sl;
2992	>	while ((sl = s.left) != null) // find successor
2993	>	s = sl;
2994	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2995	>	TreeNode<K,V> sr = s.right;
2996	>	TreeNode<K,V> pp = p.parent;
2997	>	if (s == pr) { // p was s's direct parent
2998	>	p.parent = s;
2999	>	s.right = p;
3000	>	}
3001	>	else {
3002	>	TreeNode<K,V> sp = s.parent;
3003	>	if ((p.parent = sp) != null) {
3004	>	if (s == sp.left)
3005	>	sp.left = p;
3006	>	else
3007	>	sp.right = p;
3008	>	}
3009	>	if ((s.right = pr) != null)
3010	>	pr.parent = s;
3011	>	}
3012	>	p.left = null;
3013	>	if ((p.right = sr) != null)
3014	>	sr.parent = p;
3015	>	if ((s.left = pl) != null)
3016	>	pl.parent = s;
3017	>	if ((s.parent = pp) == null)
3018	>	r = s;
3019	>	else if (p == pp.left)
3020	>	pp.left = s;
3021	>	else
3022	>	pp.right = s;
3023	>	if (sr != null)
3024	>	replacement = sr;
3025	>	else
3026	>	replacement = p;
3027	>	}
3028	>	else if (pl != null)
3029	>	replacement = pl;
3030	>	else if (pr != null)
3031	>	replacement = pr;
3032	>	else
3033	>	replacement = p;
3034	>	if (replacement != p) {
3035	>	TreeNode<K,V> pp = replacement.parent = p.parent;
3036	>	if (pp == null)
3037	>	r = replacement;
3038	>	else if (p == pp.left)
3039	>	pp.left = replacement;
3040	>	else
3041	>	pp.right = replacement;
3042	>	p.left = p.right = p.parent = null;
3043	>	}
3044	>
3045	>	root = (p.red) ? r : balanceDeletion(r, replacement);
3046	>
3047	>	if (p == replacement) {  // detach pointers
3048	>	TreeNode<K,V> pp;
3049	>	if ((pp = p.parent) != null) {
3050	>	if (p == pp.left)
3051	>	pp.left = null;
3052	>	else if (p == pp.right)
3053	>	pp.right = null;
3054	>	p.parent = null;
3055	>	}
3056	>	}
3057	>	} finally {
3058	>	unlockRoot();
3059	>	}
3060	>	assert checkInvariants(root);
3061	>	return false;
3062	>	}
3063	>
3064	>	/* ------------------------------------------------------------ */
3065	>	// Red-black tree methods, all adapted from CLR
3066	>
3067	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3068	>	TreeNode<K,V> p) {
3069	>	TreeNode<K,V> r, pp, rl;
3070	>	if (p != null && (r = p.right) != null) {
3071	>	if ((rl = p.right = r.left) != null)
3072	>	rl.parent = p;
3073	>	if ((pp = r.parent = p.parent) == null)
3074	>	(root = r).red = false;
3075	>	else if (pp.left == p)
3076	>	pp.left = r;
3077	>	else
3078	>	pp.right = r;
3079	>	r.left = p;
3080	>	p.parent = r;
3081	>	}
3082	>	return root;
3083	>	}
3084	>
3085	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3086	>	TreeNode<K,V> p) {
3087	>	TreeNode<K,V> l, pp, lr;
3088	>	if (p != null && (l = p.left) != null) {
3089	>	if ((lr = p.left = l.right) != null)
3090	>	lr.parent = p;
3091	>	if ((pp = l.parent = p.parent) == null)
3092	>	(root = l).red = false;
3093	>	else if (pp.right == p)
3094	>	pp.right = l;
3095	>	else
3096	>	pp.left = l;
3097	>	l.right = p;
3098	>	p.parent = l;
3099	>	}
3100	>	return root;
3101	>	}
3102	>
3103	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3104	>	TreeNode<K,V> x) {
3105	>	x.red = true;
3106	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3107	>	if ((xp = x.parent) == null) {
3108	>	x.red = false;
3109	>	return x;
3110	>	}
3111	>	else if (!xp.red || (xpp = xp.parent) == null)
3112	>	return root;
3113	>	if (xp == (xppl = xpp.left)) {
3114	>	if ((xppr = xpp.right) != null && xppr.red) {
3115	>	xppr.red = false;
3116	>	xp.red = false;
3117	>	xpp.red = true;
3118	>	x = xpp;
3119	>	}
3120	>	else {
3121	>	if (x == xp.right) {
3122	>	root = rotateLeft(root, x = xp);
3123	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3124	>	}
3125	>	if (xp != null) {
3126	>	xp.red = false;
3127	>	if (xpp != null) {
3128	>	xpp.red = true;
3129	>	root = rotateRight(root, xpp);
3130	>	}
3131	>	}
3132	>	}
3133	>	}
3134	>	else {
3135	>	if (xppl != null && xppl.red) {
3136	>	xppl.red = false;
3137	>	xp.red = false;
3138	>	xpp.red = true;
3139	>	x = xpp;
3140	>	}
3141	>	else {
3142	>	if (x == xp.left) {
3143	>	root = rotateRight(root, x = xp);
3144	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3145	>	}
3146	>	if (xp != null) {
3147	>	xp.red = false;
3148	>	if (xpp != null) {
3149	>	xpp.red = true;
3150	>	root = rotateLeft(root, xpp);
3151	>	}
3152	>	}
3153	>	}
3154	>	}
3155	>	}
3156	>	}
3157	>
3158	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3159	>	TreeNode<K,V> x) {
3160	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3161	>	if (x == null || x == root)
3162	>	return root;
3163	>	else if ((xp = x.parent) == null) {
3164	>	x.red = false;
3165	>	return x;
3166	>	}
3167	>	else if (x.red) {
3168	>	x.red = false;
3169	>	return root;
3170	>	}
3171	>	else if ((xpl = xp.left) == x) {
3172	>	if ((xpr = xp.right) != null && xpr.red) {
3173	>	xpr.red = false;
3174	>	xp.red = true;
3175	>	root = rotateLeft(root, xp);
3176	>	xpr = (xp = x.parent) == null ? null : xp.right;
3177	>	}
3178	>	if (xpr == null)
3179	>	x = xp;
3180	>	else {
3181	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3182	>	if ((sr == null || !sr.red) &&
3183	>	(sl == null || !sl.red)) {
3184	>	xpr.red = true;
3185	>	x = xp;
3186	>	}
3187	>	else {
3188	>	if (sr == null || !sr.red) {
3189	>	if (sl != null)
3190	>	sl.red = false;
3191	>	xpr.red = true;
3192	>	root = rotateRight(root, xpr);
3193	>	xpr = (xp = x.parent) == null ?
3194	>	null : xp.right;
3195	>	}
3196	>	if (xpr != null) {
3197	>	xpr.red = (xp == null) ? false : xp.red;
3198	>	if ((sr = xpr.right) != null)
3199	>	sr.red = false;
3200	>	}
3201	>	if (xp != null) {
3202	>	xp.red = false;
3203	>	root = rotateLeft(root, xp);
3204	>	}
3205	>	x = root;
3206	>	}
3207	>	}
3208	>	}
3209	>	else { // symmetric
3210	>	if (xpl != null && xpl.red) {
3211	>	xpl.red = false;
3212	>	xp.red = true;
3213	>	root = rotateRight(root, xp);
3214	>	xpl = (xp = x.parent) == null ? null : xp.left;
3215	>	}
3216	>	if (xpl == null)
3217	>	x = xp;
3218	>	else {
3219	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3220	>	if ((sl == null || !sl.red) &&
3221	>	(sr == null || !sr.red)) {
3222	>	xpl.red = true;
3223	>	x = xp;
3224	>	}
3225	>	else {
3226	>	if (sl == null || !sl.red) {
3227	>	if (sr != null)
3228	>	sr.red = false;
3229	>	xpl.red = true;
3230	>	root = rotateLeft(root, xpl);
3231	>	xpl = (xp = x.parent) == null ?
3232	>	null : xp.left;
3233	>	}
3234	>	if (xpl != null) {
3235	>	xpl.red = (xp == null) ? false : xp.red;
3236	>	if ((sl = xpl.left) != null)
3237	>	sl.red = false;
3238	>	}
3239	>	if (xp != null) {
3240	>	xp.red = false;
3241	>	root = rotateRight(root, xp);
3242	>	}
3243	>	x = root;
3244	>	}
3245	>	}
3246	>	}
3247	>	}
3248	>	}
3249	>
3250	>	/**
3251	>	* Checks invariants recursively for the tree of Nodes rooted at t.
3252	>	*/
3253	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3254	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3255	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3256	>	if (tb != null && tb.next != t)
3257	>	return false;
3258	>	if (tn != null && tn.prev != t)
3259	>	return false;
3260	>	if (tp != null && t != tp.left && t != tp.right)
3261	>	return false;
3262	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3263	>	return false;
3264	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3265	>	return false;
3266	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3267	>	return false;
3268	>	if (tl != null && !checkInvariants(tl))
3269	>	return false;
3270	>	if (tr != null && !checkInvariants(tr))
3271	>	return false;
3272	>	return true;
3273	>	}
3274	>
3275	>	private static final Unsafe U = Unsafe.getUnsafe();
3276	>	private static final long LOCKSTATE;
3277	>	static {
3278	>	try {
3279	>	LOCKSTATE = U.objectFieldOffset
3280	>	(TreeBin.class.getDeclaredField("lockState"));
3281	>	} catch (ReflectiveOperationException e) {
3282	>	throw new Error(e);
3283	>	}
3284	>	}
3285	>	}
3286	>
3287	>	/* ----------------Table Traversal -------------- */
3288	>
3289	>	/**
3290	>	* Records the table, its length, and current traversal index for a
3291	>	* traverser that must process a region of a forwarded table before
3292	>	* proceeding with current table.
3293	>	*/
3294	>	static final class TableStack<K,V> {
3295	>	int length;
3296	>	int index;
3297	>	Node<K,V>[] tab;
3298	>	TableStack<K,V> next;
3299	>	}
3300	>
3301	>	/**
3302	>	* Encapsulates traversal for methods such as containsValue; also
3303	>	* serves as a base class for other iterators and spliterators.
3304	>	*
3305	>	* Method advance visits once each still-valid node that was
3306	>	* reachable upon iterator construction. It might miss some that
3307	>	* were added to a bin after the bin was visited, which is OK wrt
3308	>	* consistency guarantees. Maintaining this property in the face
3309	>	* of possible ongoing resizes requires a fair amount of
3310	>	* bookkeeping state that is difficult to optimize away amidst
3311	>	* volatile accesses.  Even so, traversal maintains reasonable
3312	>	* throughput.
3313	>	*
3314	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3315	>	* However, if the table has been resized, then all future steps
3316	>	* must traverse both the bin at the current index as well as at
3317	>	* (index + baseSize); and so on for further resizings. To
3318	>	* paranoically cope with potential sharing by users of iterators
3319	>	* across threads, iteration terminates if a bounds checks fails
3320	>	* for a table read.
3321	>	*/
3322	>	static class Traverser<K,V> {
3323	>	Node<K,V>[] tab;        // current table; updated if resized
3324	>	Node<K,V> next;         // the next entry to use
3325	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3326	>	int index;              // index of bin to use next
3327	>	int baseIndex;          // current index of initial table
3328	>	int baseLimit;          // index bound for initial table
3329	>	final int baseSize;     // initial table size
3330	>
3331	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3332	>	this.tab = tab;
3333	>	this.baseSize = size;
3334	>	this.baseIndex = this.index = index;
3335	>	this.baseLimit = limit;
3336	>	this.next = null;
3337	>	}
3338	>
3339	>	/**
3340	>	* Advances if possible, returning next valid node, or null if none.
3341	>	*/
3342	>	final Node<K,V> advance() {
3343	>	Node<K,V> e;
3344	>	if ((e = next) != null)
3345	>	e = e.next;
3346	>	for (;;) {
3347	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3348	>	if (e != null)
3349	>	return next = e;
3350	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3351	>	(n = t.length) <= (i = index) || i < 0)
3352	>	return next = null;
3353	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3354	>	if (e instanceof ForwardingNode) {
3355	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3356	>	e = null;
3357	>	pushState(t, i, n);
3358	>	continue;
3359	>	}
3360	>	else if (e instanceof TreeBin)
3361	>	e = ((TreeBin<K,V>)e).first;
3362	>	else
3363	>	e = null;
3364	>	}
3365	>	if (stack != null)
3366	>	recoverState(n);
3367	>	else if ((index = i + baseSize) >= n)
3368	>	index = ++baseIndex; // visit upper slots if present
3369	>	}
3370	>	}
3371	>
3372	>	/**
3373	>	* Saves traversal state upon encountering a forwarding node.
3374	>	*/
3375	>	private void pushState(Node<K,V>[] t, int i, int n) {
3376	>	TableStack<K,V> s = spare;  // reuse if possible
3377	>	if (s != null)
3378	>	spare = s.next;
3379	>	else
3380	>	s = new TableStack<K,V>();
3381	>	s.tab = t;
3382	>	s.length = n;
3383	>	s.index = i;
3384	>	s.next = stack;
3385	>	stack = s;
3386	>	}
3387	>
3388	>	/**
3389	>	* Possibly pops traversal state.
3390	>	*
3391	>	* @param n length of current table
3392	>	*/
3393	>	private void recoverState(int n) {
3394	>	TableStack<K,V> s; int len;
3395	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3396	>	n = len;
3397	>	index = s.index;
3398	>	tab = s.tab;
3399	>	s.tab = null;
3400	>	TableStack<K,V> next = s.next;
3401	>	s.next = spare; // save for reuse
3402	>	stack = next;
3403	>	spare = s;
3404	>	}
3405	>	if (s == null && (index += baseSize) >= n)
3406	>	index = ++baseIndex;
3407	>	}
3408	>	}
3409	>
3410	>	/**
3411	>	* Base of key, value, and entry Iterators. Adds fields to
3412	>	* Traverser to support iterator.remove.
3413	>	*/
3414	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3415	>	final ConcurrentHashMap<K,V> map;
3416	>	Node<K,V> lastReturned;
3417	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3418	>	ConcurrentHashMap<K,V> map) {
3419	>	super(tab, size, index, limit);
3420	>	this.map = map;
3421		advance();
1098	–	return lastReturned;
3422		}
3423
3424	<	public void remove() {
3425	<	if (lastReturned == null)
3424	>	public final boolean hasNext() { return next != null; }
3425	>	public final boolean hasMoreElements() { return next != null; }
3426	>
3427	>	public final void remove() {
3428	>	Node<K,V> p;
3429	>	if ((p = lastReturned) == null)
3430		throw new IllegalStateException();
1104	–	ConcurrentHashMap.this.remove(lastReturned.key);
3431		lastReturned = null;
3432	+	map.replaceNode(p.key, null, null);
3433		}
3434		}
3435
3436	<	final class KeyIterator
3437	<	extends HashIterator
3438	<	implements Iterator<K>, Enumeration<K>
3439	<	{
3440	<	public K next()        { return super.nextEntry().key; }
3441	<	public K nextElement() { return super.nextEntry().key; }
3436	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3437	>	implements Iterator<K>, Enumeration<K> {
3438	>	KeyIterator(Node<K,V>[] tab, int size, int index, int limit,
3439	>	ConcurrentHashMap<K,V> map) {
3440	>	super(tab, size, index, limit, map);
3441	>	}
3442	>
3443	>	public final K next() {
3444	>	Node<K,V> p;
3445	>	if ((p = next) == null)
3446	>	throw new NoSuchElementException();
3447	>	K k = p.key;
3448	>	lastReturned = p;
3449	>	advance();
3450	>	return k;
3451	>	}
3452	>
3453	>	public final K nextElement() { return next(); }
3454		}
3455
3456	<	final class ValueIterator
3457	<	extends HashIterator
3458	<	implements Iterator<V>, Enumeration<V>
3459	<	{
3460	<	public V next()        { return super.nextEntry().value; }
3461	<	public V nextElement() { return super.nextEntry().value; }
3456	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3457	>	implements Iterator<V>, Enumeration<V> {
3458	>	ValueIterator(Node<K,V>[] tab, int size, int index, int limit,
3459	>	ConcurrentHashMap<K,V> map) {
3460	>	super(tab, size, index, limit, map);
3461	>	}
3462	>
3463	>	public final V next() {
3464	>	Node<K,V> p;
3465	>	if ((p = next) == null)
3466	>	throw new NoSuchElementException();
3467	>	V v = p.val;
3468	>	lastReturned = p;
3469	>	advance();
3470	>	return v;
3471	>	}
3472	>
3473	>	public final V nextElement() { return next(); }
3474	>	}
3475	>
3476	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3477	>	implements Iterator<Map.Entry<K,V>> {
3478	>	EntryIterator(Node<K,V>[] tab, int size, int index, int limit,
3479	>	ConcurrentHashMap<K,V> map) {
3480	>	super(tab, size, index, limit, map);
3481	>	}
3482	>
3483	>	public final Map.Entry<K,V> next() {
3484	>	Node<K,V> p;
3485	>	if ((p = next) == null)
3486	>	throw new NoSuchElementException();
3487	>	K k = p.key;
3488	>	V v = p.val;
3489	>	lastReturned = p;
3490	>	advance();
3491	>	return new MapEntry<K,V>(k, v, map);
3492	>	}
3493		}
3494
3495		/**
3496	<	* Custom Entry class used by EntryIterator.next(), that relays
1127	<	* setValue changes to the underlying map.
3496	>	* Exported Entry for EntryIterator.
3497		*/
3498	<	final class WriteThroughEntry
3499	<	extends AbstractMap.SimpleEntry<K,V>
3500	<	{
3501	<	WriteThroughEntry(K k, V v) {
3502	<	super(k,v);
3498	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3499	>	final K key; // non-null
3500	>	V val;       // non-null
3501	>	final ConcurrentHashMap<K,V> map;
3502	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3503	>	this.key = key;
3504	>	this.val = val;
3505	>	this.map = map;
3506	>	}
3507	>	public K getKey()        { return key; }
3508	>	public V getValue()      { return val; }
3509	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3510	>	public String toString() {
3511	>	return Helpers.mapEntryToString(key, val);
3512	>	}
3513	>
3514	>	public boolean equals(Object o) {
3515	>	Object k, v; Map.Entry<?,?> e;
3516	>	return ((o instanceof Map.Entry) &&
3517	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3518	>	(v = e.getValue()) != null &&
3519	>	(k == key || k.equals(key)) &&
3520	>	(v == val || v.equals(val)));
3521		}
3522
3523		/**
3524	<	* Set our entry's value and write through to the map. The
3525	<	* value to return is somewhat arbitrary here. Since a
3526	<	* WriteThroughEntry does not necessarily track asynchronous
3527	<	* changes, the most recent "previous" value could be
3528	<	* different from what we return (or could even have been
3529	<	* removed in which case the put will re-establish). We do not
1143	<	* and cannot guarantee more.
3524	>	* Sets our entry's value and writes through to the map. The
3525	>	* value to return is somewhat arbitrary here. Since we do not
3526	>	* necessarily track asynchronous changes, the most recent
3527	>	* "previous" value could be different from what we return (or
3528	>	* could even have been removed, in which case the put will
3529	>	* re-establish). We do not and cannot guarantee more.
3530		*/
3531	<	public V setValue(V value) {
3531	>	public V setValue(V value) {
3532		if (value == null) throw new NullPointerException();
3533	<	V v = super.setValue(value);
3534	<	ConcurrentHashMap.this.put(getKey(), value);
3533	>	V v = val;
3534	>	val = value;
3535	>	map.put(key, value);
3536		return v;
3537		}
3538		}
3539
3540	<	final class EntryIterator
3541	<	extends HashIterator
3542	<	implements Iterator<Entry<K,V>>
3543	<	{
3544	<	public Map.Entry<K,V> next() {
3545	<	HashEntry<K,V> e = super.nextEntry();
3546	<	return new WriteThroughEntry(e.key, e.value);
3540	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3541	>	implements Spliterator<K> {
3542	>	long est;               // size estimate
3543	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3544	>	long est) {
3545	>	super(tab, size, index, limit);
3546	>	this.est = est;
3547	>	}
3548	>
3549	>	public KeySpliterator<K,V> trySplit() {
3550	>	int i, f, h;
3551	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3552	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3553	>	f, est >>>= 1);
3554	>	}
3555	>
3556	>	public void forEachRemaining(Consumer<? super K> action) {
3557	>	if (action == null) throw new NullPointerException();
3558	>	for (Node<K,V> p; (p = advance()) != null;)
3559	>	action.accept(p.key);
3560	>	}
3561	>
3562	>	public boolean tryAdvance(Consumer<? super K> action) {
3563	>	if (action == null) throw new NullPointerException();
3564	>	Node<K,V> p;
3565	>	if ((p = advance()) == null)
3566	>	return false;
3567	>	action.accept(p.key);
3568	>	return true;
3569	>	}
3570	>
3571	>	public long estimateSize() { return est; }
3572	>
3573	>	public int characteristics() {
3574	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3575	>	Spliterator.NONNULL;
3576		}
3577		}
3578
3579	<	final class KeySet extends AbstractSet<K> {
3580	<	public Iterator<K> iterator() {
3581	<	return new KeyIterator();
3579	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3580	>	implements Spliterator<V> {
3581	>	long est;               // size estimate
3582	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3583	>	long est) {
3584	>	super(tab, size, index, limit);
3585	>	this.est = est;
3586	>	}
3587	>
3588	>	public ValueSpliterator<K,V> trySplit() {
3589	>	int i, f, h;
3590	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3591	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3592	>	f, est >>>= 1);
3593	>	}
3594	>
3595	>	public void forEachRemaining(Consumer<? super V> action) {
3596	>	if (action == null) throw new NullPointerException();
3597	>	for (Node<K,V> p; (p = advance()) != null;)
3598	>	action.accept(p.val);
3599	>	}
3600	>
3601	>	public boolean tryAdvance(Consumer<? super V> action) {
3602	>	if (action == null) throw new NullPointerException();
3603	>	Node<K,V> p;
3604	>	if ((p = advance()) == null)
3605	>	return false;
3606	>	action.accept(p.val);
3607	>	return true;
3608		}
3609	<	public int size() {
3610	<	return ConcurrentHashMap.this.size();
3609	>
3610	>	public long estimateSize() { return est; }
3611	>
3612	>	public int characteristics() {
3613	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3614		}
3615	<	public boolean contains(Object o) {
3616	<	return ConcurrentHashMap.this.containsKey(o);
3615	>	}
3616	>
3617	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3618	>	implements Spliterator<Map.Entry<K,V>> {
3619	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3620	>	long est;               // size estimate
3621	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3622	>	long est, ConcurrentHashMap<K,V> map) {
3623	>	super(tab, size, index, limit);
3624	>	this.map = map;
3625	>	this.est = est;
3626	>	}
3627	>
3628	>	public EntrySpliterator<K,V> trySplit() {
3629	>	int i, f, h;
3630	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3631	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3632	>	f, est >>>= 1, map);
3633	>	}
3634	>
3635	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3636	>	if (action == null) throw new NullPointerException();
3637	>	for (Node<K,V> p; (p = advance()) != null; )
3638	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3639	>	}
3640	>
3641	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3642	>	if (action == null) throw new NullPointerException();
3643	>	Node<K,V> p;
3644	>	if ((p = advance()) == null)
3645	>	return false;
3646	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3647	>	return true;
3648		}
3649	<	public boolean remove(Object o) {
3650	<	return ConcurrentHashMap.this.remove(o) != null;
3649	>
3650	>	public long estimateSize() { return est; }
3651	>
3652	>	public int characteristics() {
3653	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3654	>	Spliterator.NONNULL;
3655		}
3656	<	public void clear() {
3657	<	ConcurrentHashMap.this.clear();
3656	>	}
3657	>
3658	>	// Parallel bulk operations
3659	>
3660	>	/**
3661	>	* Computes initial batch value for bulk tasks. The returned value
3662	>	* is approximately exp2 of the number of times (minus one) to
3663	>	* split task by two before executing leaf action. This value is
3664	>	* faster to compute and more convenient to use as a guide to
3665	>	* splitting than is the depth, since it is used while dividing by
3666	>	* two anyway.
3667	>	*/
3668	>	final int batchFor(long b) {
3669	>	long n;
3670	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3671	>	return 0;
3672	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3673	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3674	>	}
3675	>
3676	>	/**
3677	>	* Performs the given action for each (key, value).
3678	>	*
3679	>	* @param parallelismThreshold the (estimated) number of elements
3680	>	* needed for this operation to be executed in parallel
3681	>	* @param action the action
3682	>	* @since 1.8
3683	>	*/
3684	>	public void forEach(long parallelismThreshold,
3685	>	BiConsumer<? super K,? super V> action) {
3686	>	if (action == null) throw new NullPointerException();
3687	>	new ForEachMappingTask<K,V>
3688	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3689	>	action).invoke();
3690	>	}
3691	>
3692	>	/**
3693	>	* Performs the given action for each non-null transformation
3694	>	* of each (key, value).
3695	>	*
3696	>	* @param parallelismThreshold the (estimated) number of elements
3697	>	* needed for this operation to be executed in parallel
3698	>	* @param transformer a function returning the transformation
3699	>	* for an element, or null if there is no transformation (in
3700	>	* which case the action is not applied)
3701	>	* @param action the action
3702	>	* @param <U> the return type of the transformer
3703	>	* @since 1.8
3704	>	*/
3705	>	public <U> void forEach(long parallelismThreshold,
3706	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3707	>	Consumer<? super U> action) {
3708	>	if (transformer == null || action == null)
3709	>	throw new NullPointerException();
3710	>	new ForEachTransformedMappingTask<K,V,U>
3711	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3712	>	transformer, action).invoke();
3713	>	}
3714	>
3715	>	/**
3716	>	* Returns a non-null result from applying the given search
3717	>	* function on each (key, value), or null if none.  Upon
3718	>	* success, further element processing is suppressed and the
3719	>	* results of any other parallel invocations of the search
3720	>	* function are ignored.
3721	>	*
3722	>	* @param parallelismThreshold the (estimated) number of elements
3723	>	* needed for this operation to be executed in parallel
3724	>	* @param searchFunction a function returning a non-null
3725	>	* result on success, else null
3726	>	* @param <U> the return type of the search function
3727	>	* @return a non-null result from applying the given search
3728	>	* function on each (key, value), or null if none
3729	>	* @since 1.8
3730	>	*/
3731	>	public <U> U search(long parallelismThreshold,
3732	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3733	>	if (searchFunction == null) throw new NullPointerException();
3734	>	return new SearchMappingsTask<K,V,U>
3735	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3736	>	searchFunction, new AtomicReference<U>()).invoke();
3737	>	}
3738	>
3739	>	/**
3740	>	* Returns the result of accumulating the given transformation
3741	>	* of all (key, value) pairs using the given reducer to
3742	>	* combine values, or null if none.
3743	>	*
3744	>	* @param parallelismThreshold the (estimated) number of elements
3745	>	* needed for this operation to be executed in parallel
3746	>	* @param transformer a function returning the transformation
3747	>	* for an element, or null if there is no transformation (in
3748	>	* which case it is not combined)
3749	>	* @param reducer a commutative associative combining function
3750	>	* @param <U> the return type of the transformer
3751	>	* @return the result of accumulating the given transformation
3752	>	* of all (key, value) pairs
3753	>	* @since 1.8
3754	>	*/
3755	>	public <U> U reduce(long parallelismThreshold,
3756	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3757	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3758	>	if (transformer == null || reducer == null)
3759	>	throw new NullPointerException();
3760	>	return new MapReduceMappingsTask<K,V,U>
3761	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3762	>	null, transformer, reducer).invoke();
3763	>	}
3764	>
3765	>	/**
3766	>	* Returns the result of accumulating the given transformation
3767	>	* of all (key, value) pairs using the given reducer to
3768	>	* combine values, and the given basis as an identity value.
3769	>	*
3770	>	* @param parallelismThreshold the (estimated) number of elements
3771	>	* needed for this operation to be executed in parallel
3772	>	* @param transformer a function returning the transformation
3773	>	* for an element
3774	>	* @param basis the identity (initial default value) for the reduction
3775	>	* @param reducer a commutative associative combining function
3776	>	* @return the result of accumulating the given transformation
3777	>	* of all (key, value) pairs
3778	>	* @since 1.8
3779	>	*/
3780	>	public double reduceToDouble(long parallelismThreshold,
3781	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3782	>	double basis,
3783	>	DoubleBinaryOperator reducer) {
3784	>	if (transformer == null || reducer == null)
3785	>	throw new NullPointerException();
3786	>	return new MapReduceMappingsToDoubleTask<K,V>
3787	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3788	>	null, transformer, basis, reducer).invoke();
3789	>	}
3790	>
3791	>	/**
3792	>	* Returns the result of accumulating the given transformation
3793	>	* of all (key, value) pairs using the given reducer to
3794	>	* combine values, and the given basis as an identity value.
3795	>	*
3796	>	* @param parallelismThreshold the (estimated) number of elements
3797	>	* needed for this operation to be executed in parallel
3798	>	* @param transformer a function returning the transformation
3799	>	* for an element
3800	>	* @param basis the identity (initial default value) for the reduction
3801	>	* @param reducer a commutative associative combining function
3802	>	* @return the result of accumulating the given transformation
3803	>	* of all (key, value) pairs
3804	>	* @since 1.8
3805	>	*/
3806	>	public long reduceToLong(long parallelismThreshold,
3807	>	ToLongBiFunction<? super K, ? super V> transformer,
3808	>	long basis,
3809	>	LongBinaryOperator reducer) {
3810	>	if (transformer == null || reducer == null)
3811	>	throw new NullPointerException();
3812	>	return new MapReduceMappingsToLongTask<K,V>
3813	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3814	>	null, transformer, basis, reducer).invoke();
3815	>	}
3816	>
3817	>	/**
3818	>	* Returns the result of accumulating the given transformation
3819	>	* of all (key, value) pairs using the given reducer to
3820	>	* combine values, and the given basis as an identity value.
3821	>	*
3822	>	* @param parallelismThreshold the (estimated) number of elements
3823	>	* needed for this operation to be executed in parallel
3824	>	* @param transformer a function returning the transformation
3825	>	* for an element
3826	>	* @param basis the identity (initial default value) for the reduction
3827	>	* @param reducer a commutative associative combining function
3828	>	* @return the result of accumulating the given transformation
3829	>	* of all (key, value) pairs
3830	>	* @since 1.8
3831	>	*/
3832	>	public int reduceToInt(long parallelismThreshold,
3833	>	ToIntBiFunction<? super K, ? super V> transformer,
3834	>	int basis,
3835	>	IntBinaryOperator reducer) {
3836	>	if (transformer == null || reducer == null)
3837	>	throw new NullPointerException();
3838	>	return new MapReduceMappingsToIntTask<K,V>
3839	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3840	>	null, transformer, basis, reducer).invoke();
3841	>	}
3842	>
3843	>	/**
3844	>	* Performs the given action for each key.
3845	>	*
3846	>	* @param parallelismThreshold the (estimated) number of elements
3847	>	* needed for this operation to be executed in parallel
3848	>	* @param action the action
3849	>	* @since 1.8
3850	>	*/
3851	>	public void forEachKey(long parallelismThreshold,
3852	>	Consumer<? super K> action) {
3853	>	if (action == null) throw new NullPointerException();
3854	>	new ForEachKeyTask<K,V>
3855	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3856	>	action).invoke();
3857	>	}
3858	>
3859	>	/**
3860	>	* Performs the given action for each non-null transformation
3861	>	* of each key.
3862	>	*
3863	>	* @param parallelismThreshold the (estimated) number of elements
3864	>	* needed for this operation to be executed in parallel
3865	>	* @param transformer a function returning the transformation
3866	>	* for an element, or null if there is no transformation (in
3867	>	* which case the action is not applied)
3868	>	* @param action the action
3869	>	* @param <U> the return type of the transformer
3870	>	* @since 1.8
3871	>	*/
3872	>	public <U> void forEachKey(long parallelismThreshold,
3873	>	Function<? super K, ? extends U> transformer,
3874	>	Consumer<? super U> action) {
3875	>	if (transformer == null || action == null)
3876	>	throw new NullPointerException();
3877	>	new ForEachTransformedKeyTask<K,V,U>
3878	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3879	>	transformer, action).invoke();
3880	>	}
3881	>
3882	>	/**
3883	>	* Returns a non-null result from applying the given search
3884	>	* function on each key, or null if none. Upon success,
3885	>	* further element processing is suppressed and the results of
3886	>	* any other parallel invocations of the search function are
3887	>	* ignored.
3888	>	*
3889	>	* @param parallelismThreshold the (estimated) number of elements
3890	>	* needed for this operation to be executed in parallel
3891	>	* @param searchFunction a function returning a non-null
3892	>	* result on success, else null
3893	>	* @param <U> the return type of the search function
3894	>	* @return a non-null result from applying the given search
3895	>	* function on each key, or null if none
3896	>	* @since 1.8
3897	>	*/
3898	>	public <U> U searchKeys(long parallelismThreshold,
3899	>	Function<? super K, ? extends U> searchFunction) {
3900	>	if (searchFunction == null) throw new NullPointerException();
3901	>	return new SearchKeysTask<K,V,U>
3902	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3903	>	searchFunction, new AtomicReference<U>()).invoke();
3904	>	}
3905	>
3906	>	/**
3907	>	* Returns the result of accumulating all keys using the given
3908	>	* reducer to combine values, or null if none.
3909	>	*
3910	>	* @param parallelismThreshold the (estimated) number of elements
3911	>	* needed for this operation to be executed in parallel
3912	>	* @param reducer a commutative associative combining function
3913	>	* @return the result of accumulating all keys using the given
3914	>	* reducer to combine values, or null if none
3915	>	* @since 1.8
3916	>	*/
3917	>	public K reduceKeys(long parallelismThreshold,
3918	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3919	>	if (reducer == null) throw new NullPointerException();
3920	>	return new ReduceKeysTask<K,V>
3921	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3922	>	null, reducer).invoke();
3923	>	}
3924	>
3925	>	/**
3926	>	* Returns the result of accumulating the given transformation
3927	>	* of all keys using the given reducer to combine values, or
3928	>	* null if none.
3929	>	*
3930	>	* @param parallelismThreshold the (estimated) number of elements
3931	>	* needed for this operation to be executed in parallel
3932	>	* @param transformer a function returning the transformation
3933	>	* for an element, or null if there is no transformation (in
3934	>	* which case it is not combined)
3935	>	* @param reducer a commutative associative combining function
3936	>	* @param <U> the return type of the transformer
3937	>	* @return the result of accumulating the given transformation
3938	>	* of all keys
3939	>	* @since 1.8
3940	>	*/
3941	>	public <U> U reduceKeys(long parallelismThreshold,
3942	>	Function<? super K, ? extends U> transformer,
3943	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3944	>	if (transformer == null || reducer == null)
3945	>	throw new NullPointerException();
3946	>	return new MapReduceKeysTask<K,V,U>
3947	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3948	>	null, transformer, reducer).invoke();
3949	>	}
3950	>
3951	>	/**
3952	>	* Returns the result of accumulating the given transformation
3953	>	* of all keys using the given reducer to combine values, and
3954	>	* the given basis as an identity value.
3955	>	*
3956	>	* @param parallelismThreshold the (estimated) number of elements
3957	>	* needed for this operation to be executed in parallel
3958	>	* @param transformer a function returning the transformation
3959	>	* for an element
3960	>	* @param basis the identity (initial default value) for the reduction
3961	>	* @param reducer a commutative associative combining function
3962	>	* @return the result of accumulating the given transformation
3963	>	* of all keys
3964	>	* @since 1.8
3965	>	*/
3966	>	public double reduceKeysToDouble(long parallelismThreshold,
3967	>	ToDoubleFunction<? super K> transformer,
3968	>	double basis,
3969	>	DoubleBinaryOperator reducer) {
3970	>	if (transformer == null || reducer == null)
3971	>	throw new NullPointerException();
3972	>	return new MapReduceKeysToDoubleTask<K,V>
3973	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3974	>	null, transformer, basis, reducer).invoke();
3975	>	}
3976	>
3977	>	/**
3978	>	* Returns the result of accumulating the given transformation
3979	>	* of all keys using the given reducer to combine values, and
3980	>	* the given basis as an identity value.
3981	>	*
3982	>	* @param parallelismThreshold the (estimated) number of elements
3983	>	* needed for this operation to be executed in parallel
3984	>	* @param transformer a function returning the transformation
3985	>	* for an element
3986	>	* @param basis the identity (initial default value) for the reduction
3987	>	* @param reducer a commutative associative combining function
3988	>	* @return the result of accumulating the given transformation
3989	>	* of all keys
3990	>	* @since 1.8
3991	>	*/
3992	>	public long reduceKeysToLong(long parallelismThreshold,
3993	>	ToLongFunction<? super K> transformer,
3994	>	long basis,
3995	>	LongBinaryOperator reducer) {
3996	>	if (transformer == null || reducer == null)
3997	>	throw new NullPointerException();
3998	>	return new MapReduceKeysToLongTask<K,V>
3999	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4000	>	null, transformer, basis, reducer).invoke();
4001	>	}
4002	>
4003	>	/**
4004	>	* Returns the result of accumulating the given transformation
4005	>	* of all keys using the given reducer to combine values, and
4006	>	* the given basis as an identity value.
4007	>	*
4008	>	* @param parallelismThreshold the (estimated) number of elements
4009	>	* needed for this operation to be executed in parallel
4010	>	* @param transformer a function returning the transformation
4011	>	* for an element
4012	>	* @param basis the identity (initial default value) for the reduction
4013	>	* @param reducer a commutative associative combining function
4014	>	* @return the result of accumulating the given transformation
4015	>	* of all keys
4016	>	* @since 1.8
4017	>	*/
4018	>	public int reduceKeysToInt(long parallelismThreshold,
4019	>	ToIntFunction<? super K> transformer,
4020	>	int basis,
4021	>	IntBinaryOperator reducer) {
4022	>	if (transformer == null || reducer == null)
4023	>	throw new NullPointerException();
4024	>	return new MapReduceKeysToIntTask<K,V>
4025	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4026	>	null, transformer, basis, reducer).invoke();
4027	>	}
4028	>
4029	>	/**
4030	>	* Performs the given action for each value.
4031	>	*
4032	>	* @param parallelismThreshold the (estimated) number of elements
4033	>	* needed for this operation to be executed in parallel
4034	>	* @param action the action
4035	>	* @since 1.8
4036	>	*/
4037	>	public void forEachValue(long parallelismThreshold,
4038	>	Consumer<? super V> action) {
4039	>	if (action == null)
4040	>	throw new NullPointerException();
4041	>	new ForEachValueTask<K,V>
4042	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4043	>	action).invoke();
4044	>	}
4045	>
4046	>	/**
4047	>	* Performs the given action for each non-null transformation
4048	>	* of each value.
4049	>	*
4050	>	* @param parallelismThreshold the (estimated) number of elements
4051	>	* needed for this operation to be executed in parallel
4052	>	* @param transformer a function returning the transformation
4053	>	* for an element, or null if there is no transformation (in
4054	>	* which case the action is not applied)
4055	>	* @param action the action
4056	>	* @param <U> the return type of the transformer
4057	>	* @since 1.8
4058	>	*/
4059	>	public <U> void forEachValue(long parallelismThreshold,
4060	>	Function<? super V, ? extends U> transformer,
4061	>	Consumer<? super U> action) {
4062	>	if (transformer == null || action == null)
4063	>	throw new NullPointerException();
4064	>	new ForEachTransformedValueTask<K,V,U>
4065	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4066	>	transformer, action).invoke();
4067	>	}
4068	>
4069	>	/**
4070	>	* Returns a non-null result from applying the given search
4071	>	* function on each value, or null if none.  Upon success,
4072	>	* further element processing is suppressed and the results of
4073	>	* any other parallel invocations of the search function are
4074	>	* ignored.
4075	>	*
4076	>	* @param parallelismThreshold the (estimated) number of elements
4077	>	* needed for this operation to be executed in parallel
4078	>	* @param searchFunction a function returning a non-null
4079	>	* result on success, else null
4080	>	* @param <U> the return type of the search function
4081	>	* @return a non-null result from applying the given search
4082	>	* function on each value, or null if none
4083	>	* @since 1.8
4084	>	*/
4085	>	public <U> U searchValues(long parallelismThreshold,
4086	>	Function<? super V, ? extends U> searchFunction) {
4087	>	if (searchFunction == null) throw new NullPointerException();
4088	>	return new SearchValuesTask<K,V,U>
4089	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4090	>	searchFunction, new AtomicReference<U>()).invoke();
4091	>	}
4092	>
4093	>	/**
4094	>	* Returns the result of accumulating all values using the
4095	>	* given reducer to combine values, or null if none.
4096	>	*
4097	>	* @param parallelismThreshold the (estimated) number of elements
4098	>	* needed for this operation to be executed in parallel
4099	>	* @param reducer a commutative associative combining function
4100	>	* @return the result of accumulating all values
4101	>	* @since 1.8
4102	>	*/
4103	>	public V reduceValues(long parallelismThreshold,
4104	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4105	>	if (reducer == null) throw new NullPointerException();
4106	>	return new ReduceValuesTask<K,V>
4107	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4108	>	null, reducer).invoke();
4109	>	}
4110	>
4111	>	/**
4112	>	* Returns the result of accumulating the given transformation
4113	>	* of all values using the given reducer to combine values, or
4114	>	* null if none.
4115	>	*
4116	>	* @param parallelismThreshold the (estimated) number of elements
4117	>	* needed for this operation to be executed in parallel
4118	>	* @param transformer a function returning the transformation
4119	>	* for an element, or null if there is no transformation (in
4120	>	* which case it is not combined)
4121	>	* @param reducer a commutative associative combining function
4122	>	* @param <U> the return type of the transformer
4123	>	* @return the result of accumulating the given transformation
4124	>	* of all values
4125	>	* @since 1.8
4126	>	*/
4127	>	public <U> U reduceValues(long parallelismThreshold,
4128	>	Function<? super V, ? extends U> transformer,
4129	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4130	>	if (transformer == null || reducer == null)
4131	>	throw new NullPointerException();
4132	>	return new MapReduceValuesTask<K,V,U>
4133	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4134	>	null, transformer, reducer).invoke();
4135	>	}
4136	>
4137	>	/**
4138	>	* Returns the result of accumulating the given transformation
4139	>	* of all values using the given reducer to combine values,
4140	>	* and the given basis as an identity value.
4141	>	*
4142	>	* @param parallelismThreshold the (estimated) number of elements
4143	>	* needed for this operation to be executed in parallel
4144	>	* @param transformer a function returning the transformation
4145	>	* for an element
4146	>	* @param basis the identity (initial default value) for the reduction
4147	>	* @param reducer a commutative associative combining function
4148	>	* @return the result of accumulating the given transformation
4149	>	* of all values
4150	>	* @since 1.8
4151	>	*/
4152	>	public double reduceValuesToDouble(long parallelismThreshold,
4153	>	ToDoubleFunction<? super V> transformer,
4154	>	double basis,
4155	>	DoubleBinaryOperator reducer) {
4156	>	if (transformer == null || reducer == null)
4157	>	throw new NullPointerException();
4158	>	return new MapReduceValuesToDoubleTask<K,V>
4159	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4160	>	null, transformer, basis, reducer).invoke();
4161	>	}
4162	>
4163	>	/**
4164	>	* Returns the result of accumulating the given transformation
4165	>	* of all values using the given reducer to combine values,
4166	>	* and the given basis as an identity value.
4167	>	*
4168	>	* @param parallelismThreshold the (estimated) number of elements
4169	>	* needed for this operation to be executed in parallel
4170	>	* @param transformer a function returning the transformation
4171	>	* for an element
4172	>	* @param basis the identity (initial default value) for the reduction
4173	>	* @param reducer a commutative associative combining function
4174	>	* @return the result of accumulating the given transformation
4175	>	* of all values
4176	>	* @since 1.8
4177	>	*/
4178	>	public long reduceValuesToLong(long parallelismThreshold,
4179	>	ToLongFunction<? super V> transformer,
4180	>	long basis,
4181	>	LongBinaryOperator reducer) {
4182	>	if (transformer == null || reducer == null)
4183	>	throw new NullPointerException();
4184	>	return new MapReduceValuesToLongTask<K,V>
4185	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4186	>	null, transformer, basis, reducer).invoke();
4187	>	}
4188	>
4189	>	/**
4190	>	* Returns the result of accumulating the given transformation
4191	>	* of all values using the given reducer to combine values,
4192	>	* and the given basis as an identity value.
4193	>	*
4194	>	* @param parallelismThreshold the (estimated) number of elements
4195	>	* needed for this operation to be executed in parallel
4196	>	* @param transformer a function returning the transformation
4197	>	* for an element
4198	>	* @param basis the identity (initial default value) for the reduction
4199	>	* @param reducer a commutative associative combining function
4200	>	* @return the result of accumulating the given transformation
4201	>	* of all values
4202	>	* @since 1.8
4203	>	*/
4204	>	public int reduceValuesToInt(long parallelismThreshold,
4205	>	ToIntFunction<? super V> transformer,
4206	>	int basis,
4207	>	IntBinaryOperator reducer) {
4208	>	if (transformer == null || reducer == null)
4209	>	throw new NullPointerException();
4210	>	return new MapReduceValuesToIntTask<K,V>
4211	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4212	>	null, transformer, basis, reducer).invoke();
4213	>	}
4214	>
4215	>	/**
4216	>	* Performs the given action for each entry.
4217	>	*
4218	>	* @param parallelismThreshold the (estimated) number of elements
4219	>	* needed for this operation to be executed in parallel
4220	>	* @param action the action
4221	>	* @since 1.8
4222	>	*/
4223	>	public void forEachEntry(long parallelismThreshold,
4224	>	Consumer<? super Map.Entry<K,V>> action) {
4225	>	if (action == null) throw new NullPointerException();
4226	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4227	>	action).invoke();
4228	>	}
4229	>
4230	>	/**
4231	>	* Performs the given action for each non-null transformation
4232	>	* of each entry.
4233	>	*
4234	>	* @param parallelismThreshold the (estimated) number of elements
4235	>	* needed for this operation to be executed in parallel
4236	>	* @param transformer a function returning the transformation
4237	>	* for an element, or null if there is no transformation (in
4238	>	* which case the action is not applied)
4239	>	* @param action the action
4240	>	* @param <U> the return type of the transformer
4241	>	* @since 1.8
4242	>	*/
4243	>	public <U> void forEachEntry(long parallelismThreshold,
4244	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4245	>	Consumer<? super U> action) {
4246	>	if (transformer == null || action == null)
4247	>	throw new NullPointerException();
4248	>	new ForEachTransformedEntryTask<K,V,U>
4249	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4250	>	transformer, action).invoke();
4251	>	}
4252	>
4253	>	/**
4254	>	* Returns a non-null result from applying the given search
4255	>	* function on each entry, or null if none.  Upon success,
4256	>	* further element processing is suppressed and the results of
4257	>	* any other parallel invocations of the search function are
4258	>	* ignored.
4259	>	*
4260	>	* @param parallelismThreshold the (estimated) number of elements
4261	>	* needed for this operation to be executed in parallel
4262	>	* @param searchFunction a function returning a non-null
4263	>	* result on success, else null
4264	>	* @param <U> the return type of the search function
4265	>	* @return a non-null result from applying the given search
4266	>	* function on each entry, or null if none
4267	>	* @since 1.8
4268	>	*/
4269	>	public <U> U searchEntries(long parallelismThreshold,
4270	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4271	>	if (searchFunction == null) throw new NullPointerException();
4272	>	return new SearchEntriesTask<K,V,U>
4273	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4274	>	searchFunction, new AtomicReference<U>()).invoke();
4275	>	}
4276	>
4277	>	/**
4278	>	* Returns the result of accumulating all entries using the
4279	>	* given reducer to combine values, or null if none.
4280	>	*
4281	>	* @param parallelismThreshold the (estimated) number of elements
4282	>	* needed for this operation to be executed in parallel
4283	>	* @param reducer a commutative associative combining function
4284	>	* @return the result of accumulating all entries
4285	>	* @since 1.8
4286	>	*/
4287	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4288	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4289	>	if (reducer == null) throw new NullPointerException();
4290	>	return new ReduceEntriesTask<K,V>
4291	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4292	>	null, reducer).invoke();
4293	>	}
4294	>
4295	>	/**
4296	>	* Returns the result of accumulating the given transformation
4297	>	* of all entries using the given reducer to combine values,
4298	>	* or null if none.
4299	>	*
4300	>	* @param parallelismThreshold the (estimated) number of elements
4301	>	* needed for this operation to be executed in parallel
4302	>	* @param transformer a function returning the transformation
4303	>	* for an element, or null if there is no transformation (in
4304	>	* which case it is not combined)
4305	>	* @param reducer a commutative associative combining function
4306	>	* @param <U> the return type of the transformer
4307	>	* @return the result of accumulating the given transformation
4308	>	* of all entries
4309	>	* @since 1.8
4310	>	*/
4311	>	public <U> U reduceEntries(long parallelismThreshold,
4312	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4313	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4314	>	if (transformer == null || reducer == null)
4315	>	throw new NullPointerException();
4316	>	return new MapReduceEntriesTask<K,V,U>
4317	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4318	>	null, transformer, reducer).invoke();
4319	>	}
4320	>
4321	>	/**
4322	>	* Returns the result of accumulating the given transformation
4323	>	* of all entries using the given reducer to combine values,
4324	>	* and the given basis as an identity value.
4325	>	*
4326	>	* @param parallelismThreshold the (estimated) number of elements
4327	>	* needed for this operation to be executed in parallel
4328	>	* @param transformer a function returning the transformation
4329	>	* for an element
4330	>	* @param basis the identity (initial default value) for the reduction
4331	>	* @param reducer a commutative associative combining function
4332	>	* @return the result of accumulating the given transformation
4333	>	* of all entries
4334	>	* @since 1.8
4335	>	*/
4336	>	public double reduceEntriesToDouble(long parallelismThreshold,
4337	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4338	>	double basis,
4339	>	DoubleBinaryOperator reducer) {
4340	>	if (transformer == null || reducer == null)
4341	>	throw new NullPointerException();
4342	>	return new MapReduceEntriesToDoubleTask<K,V>
4343	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4344	>	null, transformer, basis, reducer).invoke();
4345	>	}
4346	>
4347	>	/**
4348	>	* Returns the result of accumulating the given transformation
4349	>	* of all entries using the given reducer to combine values,
4350	>	* and the given basis as an identity value.
4351	>	*
4352	>	* @param parallelismThreshold the (estimated) number of elements
4353	>	* needed for this operation to be executed in parallel
4354	>	* @param transformer a function returning the transformation
4355	>	* for an element
4356	>	* @param basis the identity (initial default value) for the reduction
4357	>	* @param reducer a commutative associative combining function
4358	>	* @return the result of accumulating the given transformation
4359	>	* of all entries
4360	>	* @since 1.8
4361	>	*/
4362	>	public long reduceEntriesToLong(long parallelismThreshold,
4363	>	ToLongFunction<Map.Entry<K,V>> transformer,
4364	>	long basis,
4365	>	LongBinaryOperator reducer) {
4366	>	if (transformer == null || reducer == null)
4367	>	throw new NullPointerException();
4368	>	return new MapReduceEntriesToLongTask<K,V>
4369	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4370	>	null, transformer, basis, reducer).invoke();
4371	>	}
4372	>
4373	>	/**
4374	>	* Returns the result of accumulating the given transformation
4375	>	* of all entries using the given reducer to combine values,
4376	>	* and the given basis as an identity value.
4377	>	*
4378	>	* @param parallelismThreshold the (estimated) number of elements
4379	>	* needed for this operation to be executed in parallel
4380	>	* @param transformer a function returning the transformation
4381	>	* for an element
4382	>	* @param basis the identity (initial default value) for the reduction
4383	>	* @param reducer a commutative associative combining function
4384	>	* @return the result of accumulating the given transformation
4385	>	* of all entries
4386	>	* @since 1.8
4387	>	*/
4388	>	public int reduceEntriesToInt(long parallelismThreshold,
4389	>	ToIntFunction<Map.Entry<K,V>> transformer,
4390	>	int basis,
4391	>	IntBinaryOperator reducer) {
4392	>	if (transformer == null || reducer == null)
4393	>	throw new NullPointerException();
4394	>	return new MapReduceEntriesToIntTask<K,V>
4395	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4396	>	null, transformer, basis, reducer).invoke();
4397	>	}
4398	>
4399	>
4400	>	/* ----------------Views -------------- */
4401	>
4402	>	/**
4403	>	* Base class for views.
4404	>	*/
4405	>	abstract static class CollectionView<K,V,E>
4406	>	implements Collection<E>, java.io.Serializable {
4407	>	private static final long serialVersionUID = 7249069246763182397L;
4408	>	final ConcurrentHashMap<K,V> map;
4409	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4410	>
4411	>	/**
4412	>	* Returns the map backing this view.
4413	>	*
4414	>	* @return the map backing this view
4415	>	*/
4416	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4417	>
4418	>	/**
4419	>	* Removes all of the elements from this view, by removing all
4420	>	* the mappings from the map backing this view.
4421	>	*/
4422	>	public final void clear()      { map.clear(); }
4423	>	public final int size()        { return map.size(); }
4424	>	public final boolean isEmpty() { return map.isEmpty(); }
4425	>
4426	>	// implementations below rely on concrete classes supplying these
4427	>	// abstract methods
4428	>	/**
4429	>	* Returns an iterator over the elements in this collection.
4430	>	*
4431	>	* <p>The returned iterator is
4432	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4433	>	*
4434	>	* @return an iterator over the elements in this collection
4435	>	*/
4436	>	public abstract Iterator<E> iterator();
4437	>	public abstract boolean contains(Object o);
4438	>	public abstract boolean remove(Object o);
4439	>
4440	>	private static final String OOME_MSG = "Required array size too large";
4441	>
4442	>	public final Object[] toArray() {
4443	>	long sz = map.mappingCount();
4444	>	if (sz > MAX_ARRAY_SIZE)
4445	>	throw new OutOfMemoryError(OOME_MSG);
4446	>	int n = (int)sz;
4447	>	Object[] r = new Object[n];
4448	>	int i = 0;
4449	>	for (E e : this) {
4450	>	if (i == n) {
4451	>	if (n >= MAX_ARRAY_SIZE)
4452	>	throw new OutOfMemoryError(OOME_MSG);
4453	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4454	>	n = MAX_ARRAY_SIZE;
4455	>	else
4456	>	n += (n >>> 1) + 1;
4457	>	r = Arrays.copyOf(r, n);
4458	>	}
4459	>	r[i++] = e;
4460	>	}
4461	>	return (i == n) ? r : Arrays.copyOf(r, i);
4462	>	}
4463	>
4464	>	@SuppressWarnings("unchecked")
4465	>	public final <T> T[] toArray(T[] a) {
4466	>	long sz = map.mappingCount();
4467	>	if (sz > MAX_ARRAY_SIZE)
4468	>	throw new OutOfMemoryError(OOME_MSG);
4469	>	int m = (int)sz;
4470	>	T[] r = (a.length >= m) ? a :
4471	>	(T[])java.lang.reflect.Array
4472	>	.newInstance(a.getClass().getComponentType(), m);
4473	>	int n = r.length;
4474	>	int i = 0;
4475	>	for (E e : this) {
4476	>	if (i == n) {
4477	>	if (n >= MAX_ARRAY_SIZE)
4478	>	throw new OutOfMemoryError(OOME_MSG);
4479	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4480	>	n = MAX_ARRAY_SIZE;
4481	>	else
4482	>	n += (n >>> 1) + 1;
4483	>	r = Arrays.copyOf(r, n);
4484	>	}
4485	>	r[i++] = (T)e;
4486	>	}
4487	>	if (a == r && i < n) {
4488	>	r[i] = null; // null-terminate
4489	>	return r;
4490	>	}
4491	>	return (i == n) ? r : Arrays.copyOf(r, i);
4492		}
4493	<	public Object[] toArray() {
4494	<	Collection<K> c = new ArrayList<K>(size());
4495	<	for (K k : this)
4496	<	c.add(k);
4497	<	return c.toArray();
4493	>
4494	>	/**
4495	>	* Returns a string representation of this collection.
4496	>	* The string representation consists of the string representations
4497	>	* of the collection's elements in the order they are returned by
4498	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4499	>	* Adjacent elements are separated by the characters {@code ", "}
4500	>	* (comma and space).  Elements are converted to strings as by
4501	>	* {@link String#valueOf(Object)}.
4502	>	*
4503	>	* @return a string representation of this collection
4504	>	*/
4505	>	public final String toString() {
4506	>	StringBuilder sb = new StringBuilder();
4507	>	sb.append('[');
4508	>	Iterator<E> it = iterator();
4509	>	if (it.hasNext()) {
4510	>	for (;;) {
4511	>	Object e = it.next();
4512	>	sb.append(e == this ? "(this Collection)" : e);
4513	>	if (!it.hasNext())
4514	>	break;
4515	>	sb.append(',').append(' ');
4516	>	}
4517	>	}
4518	>	return sb.append(']').toString();
4519		}
4520	<	public <T> T[] toArray(T[] a) {
4521	<	Collection<K> c = new ArrayList<K>();
4522	<	for (K k : this)
4523	<	c.add(k);
4524	<	return c.toArray(a);
4520	>
4521	>	public final boolean containsAll(Collection<?> c) {
4522	>	if (c != this) {
4523	>	for (Object e : c) {
4524	>	if (e == null || !contains(e))
4525	>	return false;
4526	>	}
4527	>	}
4528	>	return true;
4529		}
1191	–	}
4530
4531	<	final class Values extends AbstractCollection<V> {
4532	<	public Iterator<V> iterator() {
4533	<	return new ValueIterator();
4531	>	public boolean removeAll(Collection<?> c) {
4532	>	if (c == null) throw new NullPointerException();
4533	>	boolean modified = false;
4534	>	// Use (c instanceof Set) as a hint that lookup in c is as
4535	>	// efficient as this view
4536	>	Node<K,V>[] t;
4537	>	if ((t = map.table) == null) {
4538	>	return false;
4539	>	} else if (c instanceof Set<?> && c.size() > t.length) {
4540	>	for (Iterator<?> it = iterator(); it.hasNext(); ) {
4541	>	if (c.contains(it.next())) {
4542	>	it.remove();
4543	>	modified = true;
4544	>	}
4545	>	}
4546	>	} else {
4547	>	for (Object e : c)
4548	>	modified |= remove(e);
4549	>	}
4550	>	return modified;
4551		}
4552	<	public int size() {
4553	<	return ConcurrentHashMap.this.size();
4552	>
4553	>	public final boolean retainAll(Collection<?> c) {
4554	>	if (c == null) throw new NullPointerException();
4555	>	boolean modified = false;
4556	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4557	>	if (!c.contains(it.next())) {
4558	>	it.remove();
4559	>	modified = true;
4560	>	}
4561	>	}
4562	>	return modified;
4563		}
4564	<	public boolean contains(Object o) {
4565	<	return ConcurrentHashMap.this.containsValue(o);
4564	>
4565	>	}
4566	>
4567	>	/**
4568	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4569	>	* which additions may optionally be enabled by mapping to a
4570	>	* common value.  This class cannot be directly instantiated.
4571	>	* See {@link #keySet() keySet()},
4572	>	* {@link #keySet(Object) keySet(V)},
4573	>	* {@link #newKeySet() newKeySet()},
4574	>	* {@link #newKeySet(int) newKeySet(int)}.
4575	>	*
4576	>	* @since 1.8
4577	>	*/
4578	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4579	>	implements Set<K>, java.io.Serializable {
4580	>	private static final long serialVersionUID = 7249069246763182397L;
4581	>	private final V value;
4582	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4583	>	super(map);
4584	>	this.value = value;
4585		}
4586	<	public void clear() {
4587	<	ConcurrentHashMap.this.clear();
4586	>
4587	>	/**
4588	>	* Returns the default mapped value for additions,
4589	>	* or {@code null} if additions are not supported.
4590	>	*
4591	>	* @return the default mapped value for additions, or {@code null}
4592	>	* if not supported
4593	>	*/
4594	>	public V getMappedValue() { return value; }
4595	>
4596	>	/**
4597	>	* {@inheritDoc}
4598	>	* @throws NullPointerException if the specified key is null
4599	>	*/
4600	>	public boolean contains(Object o) { return map.containsKey(o); }
4601	>
4602	>	/**
4603	>	* Removes the key from this map view, by removing the key (and its
4604	>	* corresponding value) from the backing map.  This method does
4605	>	* nothing if the key is not in the map.
4606	>	*
4607	>	* @param  o the key to be removed from the backing map
4608	>	* @return {@code true} if the backing map contained the specified key
4609	>	* @throws NullPointerException if the specified key is null
4610	>	*/
4611	>	public boolean remove(Object o) { return map.remove(o) != null; }
4612	>
4613	>	/**
4614	>	* @return an iterator over the keys of the backing map
4615	>	*/
4616	>	public Iterator<K> iterator() {
4617	>	Node<K,V>[] t;
4618	>	ConcurrentHashMap<K,V> m = map;
4619	>	int f = (t = m.table) == null ? 0 : t.length;
4620	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4621	>	}
4622	>
4623	>	/**
4624	>	* Adds the specified key to this set view by mapping the key to
4625	>	* the default mapped value in the backing map, if defined.
4626	>	*
4627	>	* @param e key to be added
4628	>	* @return {@code true} if this set changed as a result of the call
4629	>	* @throws NullPointerException if the specified key is null
4630	>	* @throws UnsupportedOperationException if no default mapped value
4631	>	* for additions was provided
4632	>	*/
4633	>	public boolean add(K e) {
4634	>	V v;
4635	>	if ((v = value) == null)
4636	>	throw new UnsupportedOperationException();
4637	>	return map.putVal(e, v, true) == null;
4638		}
4639	<	public Object[] toArray() {
4640	<	Collection<V> c = new ArrayList<V>(size());
4641	<	for (V v : this)
4642	<	c.add(v);
4643	<	return c.toArray();
4639	>
4640	>	/**
4641	>	* Adds all of the elements in the specified collection to this set,
4642	>	* as if by calling {@link #add} on each one.
4643	>	*
4644	>	* @param c the elements to be inserted into this set
4645	>	* @return {@code true} if this set changed as a result of the call
4646	>	* @throws NullPointerException if the collection or any of its
4647	>	* elements are {@code null}
4648	>	* @throws UnsupportedOperationException if no default mapped value
4649	>	* for additions was provided
4650	>	*/
4651	>	public boolean addAll(Collection<? extends K> c) {
4652	>	boolean added = false;
4653	>	V v;
4654	>	if ((v = value) == null)
4655	>	throw new UnsupportedOperationException();
4656	>	for (K e : c) {
4657	>	if (map.putVal(e, v, true) == null)
4658	>	added = true;
4659	>	}
4660	>	return added;
4661		}
4662	<	public <T> T[] toArray(T[] a) {
4663	<	Collection<V> c = new ArrayList<V>(size());
4664	<	for (V v : this)
4665	<	c.add(v);
4666	<	return c.toArray(a);
4662	>
4663	>	public int hashCode() {
4664	>	int h = 0;
4665	>	for (K e : this)
4666	>	h += e.hashCode();
4667	>	return h;
4668	>	}
4669	>
4670	>	public boolean equals(Object o) {
4671	>	Set<?> c;
4672	>	return ((o instanceof Set) &&
4673	>	((c = (Set<?>)o) == this ||
4674	>	(containsAll(c) && c.containsAll(this))));
4675	>	}
4676	>
4677	>	public Spliterator<K> spliterator() {
4678	>	Node<K,V>[] t;
4679	>	ConcurrentHashMap<K,V> m = map;
4680	>	long n = m.sumCount();
4681	>	int f = (t = m.table) == null ? 0 : t.length;
4682	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4683	>	}
4684	>
4685	>	public void forEach(Consumer<? super K> action) {
4686	>	if (action == null) throw new NullPointerException();
4687	>	Node<K,V>[] t;
4688	>	if ((t = map.table) != null) {
4689	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4690	>	for (Node<K,V> p; (p = it.advance()) != null; )
4691	>	action.accept(p.key);
4692	>	}
4693		}
4694		}
4695
4696	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4697	<	public Iterator<Map.Entry<K,V>> iterator() {
4698	<	return new EntryIterator();
4696	>	/**
4697	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4698	>	* values, in which additions are disabled. This class cannot be
4699	>	* directly instantiated. See {@link #values()}.
4700	>	*/
4701	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4702	>	implements Collection<V>, java.io.Serializable {
4703	>	private static final long serialVersionUID = 2249069246763182397L;
4704	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4705	>	public final boolean contains(Object o) {
4706	>	return map.containsValue(o);
4707	>	}
4708	>
4709	>	public final boolean remove(Object o) {
4710	>	if (o != null) {
4711	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4712	>	if (o.equals(it.next())) {
4713	>	it.remove();
4714	>	return true;
4715	>	}
4716	>	}
4717	>	}
4718	>	return false;
4719	>	}
4720	>
4721	>	public final Iterator<V> iterator() {
4722	>	ConcurrentHashMap<K,V> m = map;
4723	>	Node<K,V>[] t;
4724	>	int f = (t = m.table) == null ? 0 : t.length;
4725	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4726	>	}
4727	>
4728	>	public final boolean add(V e) {
4729	>	throw new UnsupportedOperationException();
4730	>	}
4731	>	public final boolean addAll(Collection<? extends V> c) {
4732	>	throw new UnsupportedOperationException();
4733	>	}
4734	>
4735	>	@Override public boolean removeAll(Collection<?> c) {
4736	>	if (c == null) throw new NullPointerException();
4737	>	boolean modified = false;
4738	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4739	>	if (c.contains(it.next())) {
4740	>	it.remove();
4741	>	modified = true;
4742	>	}
4743	>	}
4744	>	return modified;
4745	>	}
4746	>
4747	>	public boolean removeIf(Predicate<? super V> filter) {
4748	>	return map.removeValueIf(filter);
4749	>	}
4750	>
4751	>	public Spliterator<V> spliterator() {
4752	>	Node<K,V>[] t;
4753	>	ConcurrentHashMap<K,V> m = map;
4754	>	long n = m.sumCount();
4755	>	int f = (t = m.table) == null ? 0 : t.length;
4756	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4757		}
4758	+
4759	+	public void forEach(Consumer<? super V> action) {
4760	+	if (action == null) throw new NullPointerException();
4761	+	Node<K,V>[] t;
4762	+	if ((t = map.table) != null) {
4763	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4764	+	for (Node<K,V> p; (p = it.advance()) != null; )
4765	+	action.accept(p.val);
4766	+	}
4767	+	}
4768	+	}
4769	+
4770	+	/**
4771	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4772	+	* entries.  This class cannot be directly instantiated. See
4773	+	* {@link #entrySet()}.
4774	+	*/
4775	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4776	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4777	+	private static final long serialVersionUID = 2249069246763182397L;
4778	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4779	+
4780		public boolean contains(Object o) {
4781	<	if (!(o instanceof Map.Entry))
4782	<	return false;
4783	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4784	<	V v = ConcurrentHashMap.this.get(e.getKey());
4785	<	return v != null && v.equals(e.getValue());
4781	>	Object k, v, r; Map.Entry<?,?> e;
4782	>	return ((o instanceof Map.Entry) &&
4783	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4784	>	(r = map.get(k)) != null &&
4785	>	(v = e.getValue()) != null &&
4786	>	(v == r || v.equals(r)));
4787		}
4788	+
4789		public boolean remove(Object o) {
4790	<	if (!(o instanceof Map.Entry))
4791	<	return false;
4792	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4793	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4790	>	Object k, v; Map.Entry<?,?> e;
4791	>	return ((o instanceof Map.Entry) &&
4792	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4793	>	(v = e.getValue()) != null &&
4794	>	map.remove(k, v));
4795	>	}
4796	>
4797	>	/**
4798	>	* @return an iterator over the entries of the backing map
4799	>	*/
4800	>	public Iterator<Map.Entry<K,V>> iterator() {
4801	>	ConcurrentHashMap<K,V> m = map;
4802	>	Node<K,V>[] t;
4803	>	int f = (t = m.table) == null ? 0 : t.length;
4804	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4805		}
4806	<	public int size() {
4807	<	return ConcurrentHashMap.this.size();
4806	>
4807	>	public boolean add(Entry<K,V> e) {
4808	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4809	>	}
4810	>
4811	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4812	>	boolean added = false;
4813	>	for (Entry<K,V> e : c) {
4814	>	if (add(e))
4815	>	added = true;
4816	>	}
4817	>	return added;
4818		}
4819	<	public void clear() {
4820	<	ConcurrentHashMap.this.clear();
4819	>
4820	>	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4821	>	return map.removeEntryIf(filter);
4822		}
4823	<	public Object[] toArray() {
4824	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
4825	<	for (Map.Entry<K,V> e : this)
4826	<	c.add(e);
4827	<	return c.toArray();
4823	>
4824	>	public final int hashCode() {
4825	>	int h = 0;
4826	>	Node<K,V>[] t;
4827	>	if ((t = map.table) != null) {
4828	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4829	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4830	>	h += p.hashCode();
4831	>	}
4832	>	}
4833	>	return h;
4834		}
4835	<	public <T> T[] toArray(T[] a) {
4836	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
4837	<	for (Map.Entry<K,V> e : this)
4838	<	c.add(e);
4839	<	return c.toArray(a);
4835	>
4836	>	public final boolean equals(Object o) {
4837	>	Set<?> c;
4838	>	return ((o instanceof Set) &&
4839	>	((c = (Set<?>)o) == this ||
4840	>	(containsAll(c) && c.containsAll(this))));
4841	>	}
4842	>
4843	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4844	>	Node<K,V>[] t;
4845	>	ConcurrentHashMap<K,V> m = map;
4846	>	long n = m.sumCount();
4847	>	int f = (t = m.table) == null ? 0 : t.length;
4848	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4849	>	}
4850	>
4851	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4852	>	if (action == null) throw new NullPointerException();
4853	>	Node<K,V>[] t;
4854	>	if ((t = map.table) != null) {
4855	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4856	>	for (Node<K,V> p; (p = it.advance()) != null; )
4857	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4858	>	}
4859		}
4860
4861		}
4862
4863	<	/* ---------------- Serialization Support -------------- */
4863	>	// -------------------------------------------------------
4864
4865		/**
4866	<	* Save the state of the <tt>ConcurrentHashMap</tt> instance to a
4867	<	* 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.
4866	>	* Base class for bulk tasks. Repeats some fields and code from
4867	>	* class Traverser, because we need to subclass CountedCompleter.
4868		*/
4869	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
4870	<	s.defaultWriteObject();
4869	>	@SuppressWarnings("serial")
4870	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4871	>	Node<K,V>[] tab;        // same as Traverser
4872	>	Node<K,V> next;
4873	>	TableStack<K,V> stack, spare;
4874	>	int index;
4875	>	int baseIndex;
4876	>	int baseLimit;
4877	>	final int baseSize;
4878	>	int batch;              // split control
4879	>
4880	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4881	>	super(par);
4882	>	this.batch = b;
4883	>	this.index = this.baseIndex = i;
4884	>	if ((this.tab = t) == null)
4885	>	this.baseSize = this.baseLimit = 0;
4886	>	else if (par == null)
4887	>	this.baseSize = this.baseLimit = t.length;
4888	>	else {
4889	>	this.baseLimit = f;
4890	>	this.baseSize = par.baseSize;
4891	>	}
4892	>	}
4893
4894	<	for (int k = 0; k < segments.length; ++k) {
4895	<	Segment<K,V> seg = segments[k];
4896	<	seg.lock();
4897	<	try {
4898	<	HashEntry<K,V>[] tab = seg.table;
4899	<	for (int i = 0; i < tab.length; ++i) {
4900	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
4901	<	s.writeObject(e.key);
4902	<	s.writeObject(e.value);
4894	>	/**
4895	>	* Same as Traverser version.
4896	>	*/
4897	>	final Node<K,V> advance() {
4898	>	Node<K,V> e;
4899	>	if ((e = next) != null)
4900	>	e = e.next;
4901	>	for (;;) {
4902	>	Node<K,V>[] t; int i, n;
4903	>	if (e != null)
4904	>	return next = e;
4905	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4906	>	(n = t.length) <= (i = index) || i < 0)
4907	>	return next = null;
4908	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4909	>	if (e instanceof ForwardingNode) {
4910	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4911	>	e = null;
4912	>	pushState(t, i, n);
4913	>	continue;
4914		}
4915	+	else if (e instanceof TreeBin)
4916	+	e = ((TreeBin<K,V>)e).first;
4917	+	else
4918	+	e = null;
4919		}
4920	<	} finally {
4921	<	seg.unlock();
4920	>	if (stack != null)
4921	>	recoverState(n);
4922	>	else if ((index = i + baseSize) >= n)
4923	>	index = ++baseIndex;
4924		}
4925		}
4926	<	s.writeObject(null);
4927	<	s.writeObject(null);
4926	>
4927	>	private void pushState(Node<K,V>[] t, int i, int n) {
4928	>	TableStack<K,V> s = spare;
4929	>	if (s != null)
4930	>	spare = s.next;
4931	>	else
4932	>	s = new TableStack<K,V>();
4933	>	s.tab = t;
4934	>	s.length = n;
4935	>	s.index = i;
4936	>	s.next = stack;
4937	>	stack = s;
4938	>	}
4939	>
4940	>	private void recoverState(int n) {
4941	>	TableStack<K,V> s; int len;
4942	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4943	>	n = len;
4944	>	index = s.index;
4945	>	tab = s.tab;
4946	>	s.tab = null;
4947	>	TableStack<K,V> next = s.next;
4948	>	s.next = spare; // save for reuse
4949	>	stack = next;
4950	>	spare = s;
4951	>	}
4952	>	if (s == null && (index += baseSize) >= n)
4953	>	index = ++baseIndex;
4954	>	}
4955		}
4956
4957	<	/**
4958	<	* Reconstitute the <tt>ConcurrentHashMap</tt> instance from a
4959	<	* stream (i.e., deserialize it).
4960	<	* @param s the stream
4961	<	*/
4962	<	private void readObject(java.io.ObjectInputStream s)
4963	<	throws IOException, ClassNotFoundException  {
4964	<	s.defaultReadObject();
4957	>	/*
4958	>	* Task classes. Coded in a regular but ugly format/style to
4959	>	* simplify checks that each variant differs in the right way from
4960	>	* others. The null screenings exist because compilers cannot tell
4961	>	* that we've already null-checked task arguments, so we force
4962	>	* simplest hoisted bypass to help avoid convoluted traps.
4963	>	*/
4964	>	@SuppressWarnings("serial")
4965	>	static final class ForEachKeyTask<K,V>
4966	>	extends BulkTask<K,V,Void> {
4967	>	final Consumer<? super K> action;
4968	>	ForEachKeyTask
4969	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4970	>	Consumer<? super K> action) {
4971	>	super(p, b, i, f, t);
4972	>	this.action = action;
4973	>	}
4974	>	public final void compute() {
4975	>	final Consumer<? super K> action;
4976	>	if ((action = this.action) != null) {
4977	>	for (int i = baseIndex, f, h; batch > 0 &&
4978	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4979	>	addToPendingCount(1);
4980	>	new ForEachKeyTask<K,V>
4981	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4982	>	action).fork();
4983	>	}
4984	>	for (Node<K,V> p; (p = advance()) != null;)
4985	>	action.accept(p.key);
4986	>	propagateCompletion();
4987	>	}
4988	>	}
4989	>	}
4990
4991	<	// Initialize each segment to be minimally sized, and let grow.
4992	<	for (int i = 0; i < segments.length; ++i) {
4993	<	segments[i].setTable(new HashEntry[1]);
4991	>	@SuppressWarnings("serial")
4992	>	static final class ForEachValueTask<K,V>
4993	>	extends BulkTask<K,V,Void> {
4994	>	final Consumer<? super V> action;
4995	>	ForEachValueTask
4996	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4997	>	Consumer<? super V> action) {
4998	>	super(p, b, i, f, t);
4999	>	this.action = action;
5000	>	}
5001	>	public final void compute() {
5002	>	final Consumer<? super V> action;
5003	>	if ((action = this.action) != null) {
5004	>	for (int i = baseIndex, f, h; batch > 0 &&
5005	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5006	>	addToPendingCount(1);
5007	>	new ForEachValueTask<K,V>
5008	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5009	>	action).fork();
5010	>	}
5011	>	for (Node<K,V> p; (p = advance()) != null;)
5012	>	action.accept(p.val);
5013	>	propagateCompletion();
5014	>	}
5015		}
5016	+	}
5017
5018	<	// Read the keys and values, and put the mappings in the table
5019	<	for (;;) {
5020	<	K key = (K) s.readObject();
5021	<	V value = (V) s.readObject();
5022	<	if (key == null)
5023	<	break;
5024	<	put(key, value);
5018	>	@SuppressWarnings("serial")
5019	>	static final class ForEachEntryTask<K,V>
5020	>	extends BulkTask<K,V,Void> {
5021	>	final Consumer<? super Entry<K,V>> action;
5022	>	ForEachEntryTask
5023	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5024	>	Consumer<? super Entry<K,V>> action) {
5025	>	super(p, b, i, f, t);
5026	>	this.action = action;
5027	>	}
5028	>	public final void compute() {
5029	>	final Consumer<? super Entry<K,V>> action;
5030	>	if ((action = this.action) != null) {
5031	>	for (int i = baseIndex, f, h; batch > 0 &&
5032	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5033	>	addToPendingCount(1);
5034	>	new ForEachEntryTask<K,V>
5035	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5036	>	action).fork();
5037	>	}
5038	>	for (Node<K,V> p; (p = advance()) != null; )
5039	>	action.accept(p);
5040	>	propagateCompletion();
5041	>	}
5042	>	}
5043	>	}
5044	>
5045	>	@SuppressWarnings("serial")
5046	>	static final class ForEachMappingTask<K,V>
5047	>	extends BulkTask<K,V,Void> {
5048	>	final BiConsumer<? super K, ? super V> action;
5049	>	ForEachMappingTask
5050	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5051	>	BiConsumer<? super K,? super V> action) {
5052	>	super(p, b, i, f, t);
5053	>	this.action = action;
5054	>	}
5055	>	public final void compute() {
5056	>	final BiConsumer<? super K, ? super V> action;
5057	>	if ((action = this.action) != null) {
5058	>	for (int i = baseIndex, f, h; batch > 0 &&
5059	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5060	>	addToPendingCount(1);
5061	>	new ForEachMappingTask<K,V>
5062	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5063	>	action).fork();
5064	>	}
5065	>	for (Node<K,V> p; (p = advance()) != null; )
5066	>	action.accept(p.key, p.val);
5067	>	propagateCompletion();
5068	>	}
5069	>	}
5070	>	}
5071	>
5072	>	@SuppressWarnings("serial")
5073	>	static final class ForEachTransformedKeyTask<K,V,U>
5074	>	extends BulkTask<K,V,Void> {
5075	>	final Function<? super K, ? extends U> transformer;
5076	>	final Consumer<? super U> action;
5077	>	ForEachTransformedKeyTask
5078	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5079	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5080	>	super(p, b, i, f, t);
5081	>	this.transformer = transformer; this.action = action;
5082	>	}
5083	>	public final void compute() {
5084	>	final Function<? super K, ? extends U> transformer;
5085	>	final Consumer<? super U> action;
5086	>	if ((transformer = this.transformer) != null &&
5087	>	(action = this.action) != null) {
5088	>	for (int i = baseIndex, f, h; batch > 0 &&
5089	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5090	>	addToPendingCount(1);
5091	>	new ForEachTransformedKeyTask<K,V,U>
5092	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5093	>	transformer, action).fork();
5094	>	}
5095	>	for (Node<K,V> p; (p = advance()) != null; ) {
5096	>	U u;
5097	>	if ((u = transformer.apply(p.key)) != null)
5098	>	action.accept(u);
5099	>	}
5100	>	propagateCompletion();
5101	>	}
5102	>	}
5103	>	}
5104	>
5105	>	@SuppressWarnings("serial")
5106	>	static final class ForEachTransformedValueTask<K,V,U>
5107	>	extends BulkTask<K,V,Void> {
5108	>	final Function<? super V, ? extends U> transformer;
5109	>	final Consumer<? super U> action;
5110	>	ForEachTransformedValueTask
5111	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5112	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5113	>	super(p, b, i, f, t);
5114	>	this.transformer = transformer; this.action = action;
5115	>	}
5116	>	public final void compute() {
5117	>	final Function<? super V, ? extends U> transformer;
5118	>	final Consumer<? super U> action;
5119	>	if ((transformer = this.transformer) != null &&
5120	>	(action = this.action) != null) {
5121	>	for (int i = baseIndex, f, h; batch > 0 &&
5122	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5123	>	addToPendingCount(1);
5124	>	new ForEachTransformedValueTask<K,V,U>
5125	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5126	>	transformer, action).fork();
5127	>	}
5128	>	for (Node<K,V> p; (p = advance()) != null; ) {
5129	>	U u;
5130	>	if ((u = transformer.apply(p.val)) != null)
5131	>	action.accept(u);
5132	>	}
5133	>	propagateCompletion();
5134	>	}
5135	>	}
5136	>	}
5137	>
5138	>	@SuppressWarnings("serial")
5139	>	static final class ForEachTransformedEntryTask<K,V,U>
5140	>	extends BulkTask<K,V,Void> {
5141	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5142	>	final Consumer<? super U> action;
5143	>	ForEachTransformedEntryTask
5144	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5145	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5146	>	super(p, b, i, f, t);
5147	>	this.transformer = transformer; this.action = action;
5148	>	}
5149	>	public final void compute() {
5150	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5151	>	final Consumer<? super U> action;
5152	>	if ((transformer = this.transformer) != null &&
5153	>	(action = this.action) != null) {
5154	>	for (int i = baseIndex, f, h; batch > 0 &&
5155	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5156	>	addToPendingCount(1);
5157	>	new ForEachTransformedEntryTask<K,V,U>
5158	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5159	>	transformer, action).fork();
5160	>	}
5161	>	for (Node<K,V> p; (p = advance()) != null; ) {
5162	>	U u;
5163	>	if ((u = transformer.apply(p)) != null)
5164	>	action.accept(u);
5165	>	}
5166	>	propagateCompletion();
5167	>	}
5168	>	}
5169	>	}
5170	>
5171	>	@SuppressWarnings("serial")
5172	>	static final class ForEachTransformedMappingTask<K,V,U>
5173	>	extends BulkTask<K,V,Void> {
5174	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5175	>	final Consumer<? super U> action;
5176	>	ForEachTransformedMappingTask
5177	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5178	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5179	>	Consumer<? super U> action) {
5180	>	super(p, b, i, f, t);
5181	>	this.transformer = transformer; this.action = action;
5182	>	}
5183	>	public final void compute() {
5184	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5185	>	final Consumer<? super U> action;
5186	>	if ((transformer = this.transformer) != null &&
5187	>	(action = this.action) != null) {
5188	>	for (int i = baseIndex, f, h; batch > 0 &&
5189	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5190	>	addToPendingCount(1);
5191	>	new ForEachTransformedMappingTask<K,V,U>
5192	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5193	>	transformer, action).fork();
5194	>	}
5195	>	for (Node<K,V> p; (p = advance()) != null; ) {
5196	>	U u;
5197	>	if ((u = transformer.apply(p.key, p.val)) != null)
5198	>	action.accept(u);
5199	>	}
5200	>	propagateCompletion();
5201	>	}
5202	>	}
5203	>	}
5204	>
5205	>	@SuppressWarnings("serial")
5206	>	static final class SearchKeysTask<K,V,U>
5207	>	extends BulkTask<K,V,U> {
5208	>	final Function<? super K, ? extends U> searchFunction;
5209	>	final AtomicReference<U> result;
5210	>	SearchKeysTask
5211	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5212	>	Function<? super K, ? extends U> searchFunction,
5213	>	AtomicReference<U> result) {
5214	>	super(p, b, i, f, t);
5215	>	this.searchFunction = searchFunction; this.result = result;
5216	>	}
5217	>	public final U getRawResult() { return result.get(); }
5218	>	public final void compute() {
5219	>	final Function<? super K, ? extends U> searchFunction;
5220	>	final AtomicReference<U> result;
5221	>	if ((searchFunction = this.searchFunction) != null &&
5222	>	(result = this.result) != null) {
5223	>	for (int i = baseIndex, f, h; batch > 0 &&
5224	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5225	>	if (result.get() != null)
5226	>	return;
5227	>	addToPendingCount(1);
5228	>	new SearchKeysTask<K,V,U>
5229	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5230	>	searchFunction, result).fork();
5231	>	}
5232	>	while (result.get() == null) {
5233	>	U u;
5234	>	Node<K,V> p;
5235	>	if ((p = advance()) == null) {
5236	>	propagateCompletion();
5237	>	break;
5238	>	}
5239	>	if ((u = searchFunction.apply(p.key)) != null) {
5240	>	if (result.compareAndSet(null, u))
5241	>	quietlyCompleteRoot();
5242	>	break;
5243	>	}
5244	>	}
5245	>	}
5246	>	}
5247	>	}
5248	>
5249	>	@SuppressWarnings("serial")
5250	>	static final class SearchValuesTask<K,V,U>
5251	>	extends BulkTask<K,V,U> {
5252	>	final Function<? super V, ? extends U> searchFunction;
5253	>	final AtomicReference<U> result;
5254	>	SearchValuesTask
5255	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5256	>	Function<? super V, ? extends U> searchFunction,
5257	>	AtomicReference<U> result) {
5258	>	super(p, b, i, f, t);
5259	>	this.searchFunction = searchFunction; this.result = result;
5260	>	}
5261	>	public final U getRawResult() { return result.get(); }
5262	>	public final void compute() {
5263	>	final Function<? super V, ? extends U> searchFunction;
5264	>	final AtomicReference<U> result;
5265	>	if ((searchFunction = this.searchFunction) != null &&
5266	>	(result = this.result) != null) {
5267	>	for (int i = baseIndex, f, h; batch > 0 &&
5268	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5269	>	if (result.get() != null)
5270	>	return;
5271	>	addToPendingCount(1);
5272	>	new SearchValuesTask<K,V,U>
5273	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5274	>	searchFunction, result).fork();
5275	>	}
5276	>	while (result.get() == null) {
5277	>	U u;
5278	>	Node<K,V> p;
5279	>	if ((p = advance()) == null) {
5280	>	propagateCompletion();
5281	>	break;
5282	>	}
5283	>	if ((u = searchFunction.apply(p.val)) != null) {
5284	>	if (result.compareAndSet(null, u))
5285	>	quietlyCompleteRoot();
5286	>	break;
5287	>	}
5288	>	}
5289	>	}
5290	>	}
5291	>	}
5292	>
5293	>	@SuppressWarnings("serial")
5294	>	static final class SearchEntriesTask<K,V,U>
5295	>	extends BulkTask<K,V,U> {
5296	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5297	>	final AtomicReference<U> result;
5298	>	SearchEntriesTask
5299	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5300	>	Function<Entry<K,V>, ? extends U> searchFunction,
5301	>	AtomicReference<U> result) {
5302	>	super(p, b, i, f, t);
5303	>	this.searchFunction = searchFunction; this.result = result;
5304	>	}
5305	>	public final U getRawResult() { return result.get(); }
5306	>	public final void compute() {
5307	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5308	>	final AtomicReference<U> result;
5309	>	if ((searchFunction = this.searchFunction) != null &&
5310	>	(result = this.result) != null) {
5311	>	for (int i = baseIndex, f, h; batch > 0 &&
5312	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5313	>	if (result.get() != null)
5314	>	return;
5315	>	addToPendingCount(1);
5316	>	new SearchEntriesTask<K,V,U>
5317	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5318	>	searchFunction, result).fork();
5319	>	}
5320	>	while (result.get() == null) {
5321	>	U u;
5322	>	Node<K,V> p;
5323	>	if ((p = advance()) == null) {
5324	>	propagateCompletion();
5325	>	break;
5326	>	}
5327	>	if ((u = searchFunction.apply(p)) != null) {
5328	>	if (result.compareAndSet(null, u))
5329	>	quietlyCompleteRoot();
5330	>	return;
5331	>	}
5332	>	}
5333	>	}
5334	>	}
5335	>	}
5336	>
5337	>	@SuppressWarnings("serial")
5338	>	static final class SearchMappingsTask<K,V,U>
5339	>	extends BulkTask<K,V,U> {
5340	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5341	>	final AtomicReference<U> result;
5342	>	SearchMappingsTask
5343	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5344	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5345	>	AtomicReference<U> result) {
5346	>	super(p, b, i, f, t);
5347	>	this.searchFunction = searchFunction; this.result = result;
5348	>	}
5349	>	public final U getRawResult() { return result.get(); }
5350	>	public final void compute() {
5351	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5352	>	final AtomicReference<U> result;
5353	>	if ((searchFunction = this.searchFunction) != null &&
5354	>	(result = this.result) != null) {
5355	>	for (int i = baseIndex, f, h; batch > 0 &&
5356	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5357	>	if (result.get() != null)
5358	>	return;
5359	>	addToPendingCount(1);
5360	>	new SearchMappingsTask<K,V,U>
5361	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5362	>	searchFunction, result).fork();
5363	>	}
5364	>	while (result.get() == null) {
5365	>	U u;
5366	>	Node<K,V> p;
5367	>	if ((p = advance()) == null) {
5368	>	propagateCompletion();
5369	>	break;
5370	>	}
5371	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5372	>	if (result.compareAndSet(null, u))
5373	>	quietlyCompleteRoot();
5374	>	break;
5375	>	}
5376	>	}
5377	>	}
5378	>	}
5379	>	}
5380	>
5381	>	@SuppressWarnings("serial")
5382	>	static final class ReduceKeysTask<K,V>
5383	>	extends BulkTask<K,V,K> {
5384	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5385	>	K result;
5386	>	ReduceKeysTask<K,V> rights, nextRight;
5387	>	ReduceKeysTask
5388	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5389	>	ReduceKeysTask<K,V> nextRight,
5390	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5391	>	super(p, b, i, f, t); this.nextRight = nextRight;
5392	>	this.reducer = reducer;
5393	>	}
5394	>	public final K getRawResult() { return result; }
5395	>	public final void compute() {
5396	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5397	>	if ((reducer = this.reducer) != null) {
5398	>	for (int i = baseIndex, f, h; batch > 0 &&
5399	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5400	>	addToPendingCount(1);
5401	>	(rights = new ReduceKeysTask<K,V>
5402	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5403	>	rights, reducer)).fork();
5404	>	}
5405	>	K r = null;
5406	>	for (Node<K,V> p; (p = advance()) != null; ) {
5407	>	K u = p.key;
5408	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5409	>	}
5410	>	result = r;
5411	>	CountedCompleter<?> c;
5412	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5413	>	@SuppressWarnings("unchecked")
5414	>	ReduceKeysTask<K,V>
5415	>	t = (ReduceKeysTask<K,V>)c,
5416	>	s = t.rights;
5417	>	while (s != null) {
5418	>	K tr, sr;
5419	>	if ((sr = s.result) != null)
5420	>	t.result = (((tr = t.result) == null) ? sr :
5421	>	reducer.apply(tr, sr));
5422	>	s = t.rights = s.nextRight;
5423	>	}
5424	>	}
5425	>	}
5426	>	}
5427	>	}
5428	>
5429	>	@SuppressWarnings("serial")
5430	>	static final class ReduceValuesTask<K,V>
5431	>	extends BulkTask<K,V,V> {
5432	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5433	>	V result;
5434	>	ReduceValuesTask<K,V> rights, nextRight;
5435	>	ReduceValuesTask
5436	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5437	>	ReduceValuesTask<K,V> nextRight,
5438	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5439	>	super(p, b, i, f, t); this.nextRight = nextRight;
5440	>	this.reducer = reducer;
5441	>	}
5442	>	public final V getRawResult() { return result; }
5443	>	public final void compute() {
5444	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5445	>	if ((reducer = this.reducer) != null) {
5446	>	for (int i = baseIndex, f, h; batch > 0 &&
5447	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5448	>	addToPendingCount(1);
5449	>	(rights = new ReduceValuesTask<K,V>
5450	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5451	>	rights, reducer)).fork();
5452	>	}
5453	>	V r = null;
5454	>	for (Node<K,V> p; (p = advance()) != null; ) {
5455	>	V v = p.val;
5456	>	r = (r == null) ? v : reducer.apply(r, v);
5457	>	}
5458	>	result = r;
5459	>	CountedCompleter<?> c;
5460	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5461	>	@SuppressWarnings("unchecked")
5462	>	ReduceValuesTask<K,V>
5463	>	t = (ReduceValuesTask<K,V>)c,
5464	>	s = t.rights;
5465	>	while (s != null) {
5466	>	V tr, sr;
5467	>	if ((sr = s.result) != null)
5468	>	t.result = (((tr = t.result) == null) ? sr :
5469	>	reducer.apply(tr, sr));
5470	>	s = t.rights = s.nextRight;
5471	>	}
5472	>	}
5473	>	}
5474	>	}
5475	>	}
5476	>
5477	>	@SuppressWarnings("serial")
5478	>	static final class ReduceEntriesTask<K,V>
5479	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5480	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5481	>	Map.Entry<K,V> result;
5482	>	ReduceEntriesTask<K,V> rights, nextRight;
5483	>	ReduceEntriesTask
5484	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5485	>	ReduceEntriesTask<K,V> nextRight,
5486	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5487	>	super(p, b, i, f, t); this.nextRight = nextRight;
5488	>	this.reducer = reducer;
5489	>	}
5490	>	public final Map.Entry<K,V> getRawResult() { return result; }
5491	>	public final void compute() {
5492	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5493	>	if ((reducer = this.reducer) != null) {
5494	>	for (int i = baseIndex, f, h; batch > 0 &&
5495	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5496	>	addToPendingCount(1);
5497	>	(rights = new ReduceEntriesTask<K,V>
5498	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5499	>	rights, reducer)).fork();
5500	>	}
5501	>	Map.Entry<K,V> r = null;
5502	>	for (Node<K,V> p; (p = advance()) != null; )
5503	>	r = (r == null) ? p : reducer.apply(r, p);
5504	>	result = r;
5505	>	CountedCompleter<?> c;
5506	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5507	>	@SuppressWarnings("unchecked")
5508	>	ReduceEntriesTask<K,V>
5509	>	t = (ReduceEntriesTask<K,V>)c,
5510	>	s = t.rights;
5511	>	while (s != null) {
5512	>	Map.Entry<K,V> tr, sr;
5513	>	if ((sr = s.result) != null)
5514	>	t.result = (((tr = t.result) == null) ? sr :
5515	>	reducer.apply(tr, sr));
5516	>	s = t.rights = s.nextRight;
5517	>	}
5518	>	}
5519	>	}
5520	>	}
5521	>	}
5522	>
5523	>	@SuppressWarnings("serial")
5524	>	static final class MapReduceKeysTask<K,V,U>
5525	>	extends BulkTask<K,V,U> {
5526	>	final Function<? super K, ? extends U> transformer;
5527	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5528	>	U result;
5529	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5530	>	MapReduceKeysTask
5531	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5532	>	MapReduceKeysTask<K,V,U> nextRight,
5533	>	Function<? super K, ? extends U> transformer,
5534	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5535	>	super(p, b, i, f, t); this.nextRight = nextRight;
5536	>	this.transformer = transformer;
5537	>	this.reducer = reducer;
5538	>	}
5539	>	public final U getRawResult() { return result; }
5540	>	public final void compute() {
5541	>	final Function<? super K, ? extends U> transformer;
5542	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5543	>	if ((transformer = this.transformer) != null &&
5544	>	(reducer = this.reducer) != null) {
5545	>	for (int i = baseIndex, f, h; batch > 0 &&
5546	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5547	>	addToPendingCount(1);
5548	>	(rights = new MapReduceKeysTask<K,V,U>
5549	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5550	>	rights, transformer, reducer)).fork();
5551	>	}
5552	>	U r = null;
5553	>	for (Node<K,V> p; (p = advance()) != null; ) {
5554	>	U u;
5555	>	if ((u = transformer.apply(p.key)) != null)
5556	>	r = (r == null) ? u : reducer.apply(r, u);
5557	>	}
5558	>	result = r;
5559	>	CountedCompleter<?> c;
5560	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5561	>	@SuppressWarnings("unchecked")
5562	>	MapReduceKeysTask<K,V,U>
5563	>	t = (MapReduceKeysTask<K,V,U>)c,
5564	>	s = t.rights;
5565	>	while (s != null) {
5566	>	U tr, sr;
5567	>	if ((sr = s.result) != null)
5568	>	t.result = (((tr = t.result) == null) ? sr :
5569	>	reducer.apply(tr, sr));
5570	>	s = t.rights = s.nextRight;
5571	>	}
5572	>	}
5573	>	}
5574	>	}
5575	>	}
5576	>
5577	>	@SuppressWarnings("serial")
5578	>	static final class MapReduceValuesTask<K,V,U>
5579	>	extends BulkTask<K,V,U> {
5580	>	final Function<? super V, ? extends U> transformer;
5581	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5582	>	U result;
5583	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5584	>	MapReduceValuesTask
5585	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5586	>	MapReduceValuesTask<K,V,U> nextRight,
5587	>	Function<? super V, ? extends U> transformer,
5588	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5589	>	super(p, b, i, f, t); this.nextRight = nextRight;
5590	>	this.transformer = transformer;
5591	>	this.reducer = reducer;
5592	>	}
5593	>	public final U getRawResult() { return result; }
5594	>	public final void compute() {
5595	>	final Function<? super V, ? extends U> transformer;
5596	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5597	>	if ((transformer = this.transformer) != null &&
5598	>	(reducer = this.reducer) != null) {
5599	>	for (int i = baseIndex, f, h; batch > 0 &&
5600	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5601	>	addToPendingCount(1);
5602	>	(rights = new MapReduceValuesTask<K,V,U>
5603	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5604	>	rights, transformer, reducer)).fork();
5605	>	}
5606	>	U r = null;
5607	>	for (Node<K,V> p; (p = advance()) != null; ) {
5608	>	U u;
5609	>	if ((u = transformer.apply(p.val)) != null)
5610	>	r = (r == null) ? u : reducer.apply(r, u);
5611	>	}
5612	>	result = r;
5613	>	CountedCompleter<?> c;
5614	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5615	>	@SuppressWarnings("unchecked")
5616	>	MapReduceValuesTask<K,V,U>
5617	>	t = (MapReduceValuesTask<K,V,U>)c,
5618	>	s = t.rights;
5619	>	while (s != null) {
5620	>	U tr, sr;
5621	>	if ((sr = s.result) != null)
5622	>	t.result = (((tr = t.result) == null) ? sr :
5623	>	reducer.apply(tr, sr));
5624	>	s = t.rights = s.nextRight;
5625	>	}
5626	>	}
5627	>	}
5628	>	}
5629	>	}
5630	>
5631	>	@SuppressWarnings("serial")
5632	>	static final class MapReduceEntriesTask<K,V,U>
5633	>	extends BulkTask<K,V,U> {
5634	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5635	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5636	>	U result;
5637	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5638	>	MapReduceEntriesTask
5639	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5640	>	MapReduceEntriesTask<K,V,U> nextRight,
5641	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5642	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5643	>	super(p, b, i, f, t); this.nextRight = nextRight;
5644	>	this.transformer = transformer;
5645	>	this.reducer = reducer;
5646	>	}
5647	>	public final U getRawResult() { return result; }
5648	>	public final void compute() {
5649	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5650	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5651	>	if ((transformer = this.transformer) != null &&
5652	>	(reducer = this.reducer) != null) {
5653	>	for (int i = baseIndex, f, h; batch > 0 &&
5654	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5655	>	addToPendingCount(1);
5656	>	(rights = new MapReduceEntriesTask<K,V,U>
5657	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5658	>	rights, transformer, reducer)).fork();
5659	>	}
5660	>	U r = null;
5661	>	for (Node<K,V> p; (p = advance()) != null; ) {
5662	>	U u;
5663	>	if ((u = transformer.apply(p)) != null)
5664	>	r = (r == null) ? u : reducer.apply(r, u);
5665	>	}
5666	>	result = r;
5667	>	CountedCompleter<?> c;
5668	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5669	>	@SuppressWarnings("unchecked")
5670	>	MapReduceEntriesTask<K,V,U>
5671	>	t = (MapReduceEntriesTask<K,V,U>)c,
5672	>	s = t.rights;
5673	>	while (s != null) {
5674	>	U tr, sr;
5675	>	if ((sr = s.result) != null)
5676	>	t.result = (((tr = t.result) == null) ? sr :
5677	>	reducer.apply(tr, sr));
5678	>	s = t.rights = s.nextRight;
5679	>	}
5680	>	}
5681	>	}
5682	>	}
5683	>	}
5684	>
5685	>	@SuppressWarnings("serial")
5686	>	static final class MapReduceMappingsTask<K,V,U>
5687	>	extends BulkTask<K,V,U> {
5688	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5689	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5690	>	U result;
5691	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5692	>	MapReduceMappingsTask
5693	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5694	>	MapReduceMappingsTask<K,V,U> nextRight,
5695	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5696	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5697	>	super(p, b, i, f, t); this.nextRight = nextRight;
5698	>	this.transformer = transformer;
5699	>	this.reducer = reducer;
5700	>	}
5701	>	public final U getRawResult() { return result; }
5702	>	public final void compute() {
5703	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5704	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5705	>	if ((transformer = this.transformer) != null &&
5706	>	(reducer = this.reducer) != null) {
5707	>	for (int i = baseIndex, f, h; batch > 0 &&
5708	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5709	>	addToPendingCount(1);
5710	>	(rights = new MapReduceMappingsTask<K,V,U>
5711	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5712	>	rights, transformer, reducer)).fork();
5713	>	}
5714	>	U r = null;
5715	>	for (Node<K,V> p; (p = advance()) != null; ) {
5716	>	U u;
5717	>	if ((u = transformer.apply(p.key, p.val)) != null)
5718	>	r = (r == null) ? u : reducer.apply(r, u);
5719	>	}
5720	>	result = r;
5721	>	CountedCompleter<?> c;
5722	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5723	>	@SuppressWarnings("unchecked")
5724	>	MapReduceMappingsTask<K,V,U>
5725	>	t = (MapReduceMappingsTask<K,V,U>)c,
5726	>	s = t.rights;
5727	>	while (s != null) {
5728	>	U tr, sr;
5729	>	if ((sr = s.result) != null)
5730	>	t.result = (((tr = t.result) == null) ? sr :
5731	>	reducer.apply(tr, sr));
5732	>	s = t.rights = s.nextRight;
5733	>	}
5734	>	}
5735	>	}
5736	>	}
5737	>	}
5738	>
5739	>	@SuppressWarnings("serial")
5740	>	static final class MapReduceKeysToDoubleTask<K,V>
5741	>	extends BulkTask<K,V,Double> {
5742	>	final ToDoubleFunction<? super K> transformer;
5743	>	final DoubleBinaryOperator reducer;
5744	>	final double basis;
5745	>	double result;
5746	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5747	>	MapReduceKeysToDoubleTask
5748	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5749	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5750	>	ToDoubleFunction<? super K> transformer,
5751	>	double basis,
5752	>	DoubleBinaryOperator reducer) {
5753	>	super(p, b, i, f, t); this.nextRight = nextRight;
5754	>	this.transformer = transformer;
5755	>	this.basis = basis; this.reducer = reducer;
5756	>	}
5757	>	public final Double getRawResult() { return result; }
5758	>	public final void compute() {
5759	>	final ToDoubleFunction<? super K> transformer;
5760	>	final DoubleBinaryOperator reducer;
5761	>	if ((transformer = this.transformer) != null &&
5762	>	(reducer = this.reducer) != null) {
5763	>	double r = this.basis;
5764	>	for (int i = baseIndex, f, h; batch > 0 &&
5765	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5766	>	addToPendingCount(1);
5767	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5768	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5769	>	rights, transformer, r, reducer)).fork();
5770	>	}
5771	>	for (Node<K,V> p; (p = advance()) != null; )
5772	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5773	>	result = r;
5774	>	CountedCompleter<?> c;
5775	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5776	>	@SuppressWarnings("unchecked")
5777	>	MapReduceKeysToDoubleTask<K,V>
5778	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5779	>	s = t.rights;
5780	>	while (s != null) {
5781	>	t.result = reducer.applyAsDouble(t.result, s.result);
5782	>	s = t.rights = s.nextRight;
5783	>	}
5784	>	}
5785	>	}
5786	>	}
5787	>	}
5788	>
5789	>	@SuppressWarnings("serial")
5790	>	static final class MapReduceValuesToDoubleTask<K,V>
5791	>	extends BulkTask<K,V,Double> {
5792	>	final ToDoubleFunction<? super V> transformer;
5793	>	final DoubleBinaryOperator reducer;
5794	>	final double basis;
5795	>	double result;
5796	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5797	>	MapReduceValuesToDoubleTask
5798	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5799	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5800	>	ToDoubleFunction<? super V> transformer,
5801	>	double basis,
5802	>	DoubleBinaryOperator reducer) {
5803	>	super(p, b, i, f, t); this.nextRight = nextRight;
5804	>	this.transformer = transformer;
5805	>	this.basis = basis; this.reducer = reducer;
5806	>	}
5807	>	public final Double getRawResult() { return result; }
5808	>	public final void compute() {
5809	>	final ToDoubleFunction<? super V> transformer;
5810	>	final DoubleBinaryOperator reducer;
5811	>	if ((transformer = this.transformer) != null &&
5812	>	(reducer = this.reducer) != null) {
5813	>	double r = this.basis;
5814	>	for (int i = baseIndex, f, h; batch > 0 &&
5815	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5816	>	addToPendingCount(1);
5817	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5818	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5819	>	rights, transformer, r, reducer)).fork();
5820	>	}
5821	>	for (Node<K,V> p; (p = advance()) != null; )
5822	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5823	>	result = r;
5824	>	CountedCompleter<?> c;
5825	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5826	>	@SuppressWarnings("unchecked")
5827	>	MapReduceValuesToDoubleTask<K,V>
5828	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5829	>	s = t.rights;
5830	>	while (s != null) {
5831	>	t.result = reducer.applyAsDouble(t.result, s.result);
5832	>	s = t.rights = s.nextRight;
5833	>	}
5834	>	}
5835	>	}
5836	>	}
5837	>	}
5838	>
5839	>	@SuppressWarnings("serial")
5840	>	static final class MapReduceEntriesToDoubleTask<K,V>
5841	>	extends BulkTask<K,V,Double> {
5842	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5843	>	final DoubleBinaryOperator reducer;
5844	>	final double basis;
5845	>	double result;
5846	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5847	>	MapReduceEntriesToDoubleTask
5848	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5849	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5850	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5851	>	double basis,
5852	>	DoubleBinaryOperator reducer) {
5853	>	super(p, b, i, f, t); this.nextRight = nextRight;
5854	>	this.transformer = transformer;
5855	>	this.basis = basis; this.reducer = reducer;
5856	>	}
5857	>	public final Double getRawResult() { return result; }
5858	>	public final void compute() {
5859	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5860	>	final DoubleBinaryOperator reducer;
5861	>	if ((transformer = this.transformer) != null &&
5862	>	(reducer = this.reducer) != null) {
5863	>	double r = this.basis;
5864	>	for (int i = baseIndex, f, h; batch > 0 &&
5865	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5866	>	addToPendingCount(1);
5867	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5868	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5869	>	rights, transformer, r, reducer)).fork();
5870	>	}
5871	>	for (Node<K,V> p; (p = advance()) != null; )
5872	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5873	>	result = r;
5874	>	CountedCompleter<?> c;
5875	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5876	>	@SuppressWarnings("unchecked")
5877	>	MapReduceEntriesToDoubleTask<K,V>
5878	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5879	>	s = t.rights;
5880	>	while (s != null) {
5881	>	t.result = reducer.applyAsDouble(t.result, s.result);
5882	>	s = t.rights = s.nextRight;
5883	>	}
5884	>	}
5885	>	}
5886	>	}
5887	>	}
5888	>
5889	>	@SuppressWarnings("serial")
5890	>	static final class MapReduceMappingsToDoubleTask<K,V>
5891	>	extends BulkTask<K,V,Double> {
5892	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5893	>	final DoubleBinaryOperator reducer;
5894	>	final double basis;
5895	>	double result;
5896	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5897	>	MapReduceMappingsToDoubleTask
5898	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5899	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5900	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5901	>	double basis,
5902	>	DoubleBinaryOperator reducer) {
5903	>	super(p, b, i, f, t); this.nextRight = nextRight;
5904	>	this.transformer = transformer;
5905	>	this.basis = basis; this.reducer = reducer;
5906	>	}
5907	>	public final Double getRawResult() { return result; }
5908	>	public final void compute() {
5909	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5910	>	final DoubleBinaryOperator reducer;
5911	>	if ((transformer = this.transformer) != null &&
5912	>	(reducer = this.reducer) != null) {
5913	>	double r = this.basis;
5914	>	for (int i = baseIndex, f, h; batch > 0 &&
5915	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5916	>	addToPendingCount(1);
5917	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5918	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5919	>	rights, transformer, r, reducer)).fork();
5920	>	}
5921	>	for (Node<K,V> p; (p = advance()) != null; )
5922	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5923	>	result = r;
5924	>	CountedCompleter<?> c;
5925	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5926	>	@SuppressWarnings("unchecked")
5927	>	MapReduceMappingsToDoubleTask<K,V>
5928	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5929	>	s = t.rights;
5930	>	while (s != null) {
5931	>	t.result = reducer.applyAsDouble(t.result, s.result);
5932	>	s = t.rights = s.nextRight;
5933	>	}
5934	>	}
5935	>	}
5936	>	}
5937	>	}
5938	>
5939	>	@SuppressWarnings("serial")
5940	>	static final class MapReduceKeysToLongTask<K,V>
5941	>	extends BulkTask<K,V,Long> {
5942	>	final ToLongFunction<? super K> transformer;
5943	>	final LongBinaryOperator reducer;
5944	>	final long basis;
5945	>	long result;
5946	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5947	>	MapReduceKeysToLongTask
5948	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5949	>	MapReduceKeysToLongTask<K,V> nextRight,
5950	>	ToLongFunction<? super K> transformer,
5951	>	long basis,
5952	>	LongBinaryOperator reducer) {
5953	>	super(p, b, i, f, t); this.nextRight = nextRight;
5954	>	this.transformer = transformer;
5955	>	this.basis = basis; this.reducer = reducer;
5956	>	}
5957	>	public final Long getRawResult() { return result; }
5958	>	public final void compute() {
5959	>	final ToLongFunction<? super K> transformer;
5960	>	final LongBinaryOperator reducer;
5961	>	if ((transformer = this.transformer) != null &&
5962	>	(reducer = this.reducer) != null) {
5963	>	long r = this.basis;
5964	>	for (int i = baseIndex, f, h; batch > 0 &&
5965	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5966	>	addToPendingCount(1);
5967	>	(rights = new MapReduceKeysToLongTask<K,V>
5968	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5969	>	rights, transformer, r, reducer)).fork();
5970	>	}
5971	>	for (Node<K,V> p; (p = advance()) != null; )
5972	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5973	>	result = r;
5974	>	CountedCompleter<?> c;
5975	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5976	>	@SuppressWarnings("unchecked")
5977	>	MapReduceKeysToLongTask<K,V>
5978	>	t = (MapReduceKeysToLongTask<K,V>)c,
5979	>	s = t.rights;
5980	>	while (s != null) {
5981	>	t.result = reducer.applyAsLong(t.result, s.result);
5982	>	s = t.rights = s.nextRight;
5983	>	}
5984	>	}
5985	>	}
5986	>	}
5987	>	}
5988	>
5989	>	@SuppressWarnings("serial")
5990	>	static final class MapReduceValuesToLongTask<K,V>
5991	>	extends BulkTask<K,V,Long> {
5992	>	final ToLongFunction<? super V> transformer;
5993	>	final LongBinaryOperator reducer;
5994	>	final long basis;
5995	>	long result;
5996	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5997	>	MapReduceValuesToLongTask
5998	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5999	>	MapReduceValuesToLongTask<K,V> nextRight,
6000	>	ToLongFunction<? super V> transformer,
6001	>	long basis,
6002	>	LongBinaryOperator reducer) {
6003	>	super(p, b, i, f, t); this.nextRight = nextRight;
6004	>	this.transformer = transformer;
6005	>	this.basis = basis; this.reducer = reducer;
6006	>	}
6007	>	public final Long getRawResult() { return result; }
6008	>	public final void compute() {
6009	>	final ToLongFunction<? super V> transformer;
6010	>	final LongBinaryOperator reducer;
6011	>	if ((transformer = this.transformer) != null &&
6012	>	(reducer = this.reducer) != null) {
6013	>	long r = this.basis;
6014	>	for (int i = baseIndex, f, h; batch > 0 &&
6015	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6016	>	addToPendingCount(1);
6017	>	(rights = new MapReduceValuesToLongTask<K,V>
6018	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6019	>	rights, transformer, r, reducer)).fork();
6020	>	}
6021	>	for (Node<K,V> p; (p = advance()) != null; )
6022	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
6023	>	result = r;
6024	>	CountedCompleter<?> c;
6025	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6026	>	@SuppressWarnings("unchecked")
6027	>	MapReduceValuesToLongTask<K,V>
6028	>	t = (MapReduceValuesToLongTask<K,V>)c,
6029	>	s = t.rights;
6030	>	while (s != null) {
6031	>	t.result = reducer.applyAsLong(t.result, s.result);
6032	>	s = t.rights = s.nextRight;
6033	>	}
6034	>	}
6035	>	}
6036		}
6037		}
6038	+
6039	+	@SuppressWarnings("serial")
6040	+	static final class MapReduceEntriesToLongTask<K,V>
6041	+	extends BulkTask<K,V,Long> {
6042	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6043	+	final LongBinaryOperator reducer;
6044	+	final long basis;
6045	+	long result;
6046	+	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6047	+	MapReduceEntriesToLongTask
6048	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6049	+	MapReduceEntriesToLongTask<K,V> nextRight,
6050	+	ToLongFunction<Map.Entry<K,V>> transformer,
6051	+	long basis,
6052	+	LongBinaryOperator reducer) {
6053	+	super(p, b, i, f, t); this.nextRight = nextRight;
6054	+	this.transformer = transformer;
6055	+	this.basis = basis; this.reducer = reducer;
6056	+	}
6057	+	public final Long getRawResult() { return result; }
6058	+	public final void compute() {
6059	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6060	+	final LongBinaryOperator reducer;
6061	+	if ((transformer = this.transformer) != null &&
6062	+	(reducer = this.reducer) != null) {
6063	+	long r = this.basis;
6064	+	for (int i = baseIndex, f, h; batch > 0 &&
6065	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6066	+	addToPendingCount(1);
6067	+	(rights = new MapReduceEntriesToLongTask<K,V>
6068	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6069	+	rights, transformer, r, reducer)).fork();
6070	+	}
6071	+	for (Node<K,V> p; (p = advance()) != null; )
6072	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6073	+	result = r;
6074	+	CountedCompleter<?> c;
6075	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6076	+	@SuppressWarnings("unchecked")
6077	+	MapReduceEntriesToLongTask<K,V>
6078	+	t = (MapReduceEntriesToLongTask<K,V>)c,
6079	+	s = t.rights;
6080	+	while (s != null) {
6081	+	t.result = reducer.applyAsLong(t.result, s.result);
6082	+	s = t.rights = s.nextRight;
6083	+	}
6084	+	}
6085	+	}
6086	+	}
6087	+	}
6088	+
6089	+	@SuppressWarnings("serial")
6090	+	static final class MapReduceMappingsToLongTask<K,V>
6091	+	extends BulkTask<K,V,Long> {
6092	+	final ToLongBiFunction<? super K, ? super V> transformer;
6093	+	final LongBinaryOperator reducer;
6094	+	final long basis;
6095	+	long result;
6096	+	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6097	+	MapReduceMappingsToLongTask
6098	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6099	+	MapReduceMappingsToLongTask<K,V> nextRight,
6100	+	ToLongBiFunction<? super K, ? super V> transformer,
6101	+	long basis,
6102	+	LongBinaryOperator reducer) {
6103	+	super(p, b, i, f, t); this.nextRight = nextRight;
6104	+	this.transformer = transformer;
6105	+	this.basis = basis; this.reducer = reducer;
6106	+	}
6107	+	public final Long getRawResult() { return result; }
6108	+	public final void compute() {
6109	+	final ToLongBiFunction<? super K, ? super V> transformer;
6110	+	final LongBinaryOperator reducer;
6111	+	if ((transformer = this.transformer) != null &&
6112	+	(reducer = this.reducer) != null) {
6113	+	long r = this.basis;
6114	+	for (int i = baseIndex, f, h; batch > 0 &&
6115	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6116	+	addToPendingCount(1);
6117	+	(rights = new MapReduceMappingsToLongTask<K,V>
6118	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6119	+	rights, transformer, r, reducer)).fork();
6120	+	}
6121	+	for (Node<K,V> p; (p = advance()) != null; )
6122	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6123	+	result = r;
6124	+	CountedCompleter<?> c;
6125	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6126	+	@SuppressWarnings("unchecked")
6127	+	MapReduceMappingsToLongTask<K,V>
6128	+	t = (MapReduceMappingsToLongTask<K,V>)c,
6129	+	s = t.rights;
6130	+	while (s != null) {
6131	+	t.result = reducer.applyAsLong(t.result, s.result);
6132	+	s = t.rights = s.nextRight;
6133	+	}
6134	+	}
6135	+	}
6136	+	}
6137	+	}
6138	+
6139	+	@SuppressWarnings("serial")
6140	+	static final class MapReduceKeysToIntTask<K,V>
6141	+	extends BulkTask<K,V,Integer> {
6142	+	final ToIntFunction<? super K> transformer;
6143	+	final IntBinaryOperator reducer;
6144	+	final int basis;
6145	+	int result;
6146	+	MapReduceKeysToIntTask<K,V> rights, nextRight;
6147	+	MapReduceKeysToIntTask
6148	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6149	+	MapReduceKeysToIntTask<K,V> nextRight,
6150	+	ToIntFunction<? super K> transformer,
6151	+	int basis,
6152	+	IntBinaryOperator reducer) {
6153	+	super(p, b, i, f, t); this.nextRight = nextRight;
6154	+	this.transformer = transformer;
6155	+	this.basis = basis; this.reducer = reducer;
6156	+	}
6157	+	public final Integer getRawResult() { return result; }
6158	+	public final void compute() {
6159	+	final ToIntFunction<? super K> transformer;
6160	+	final IntBinaryOperator reducer;
6161	+	if ((transformer = this.transformer) != null &&
6162	+	(reducer = this.reducer) != null) {
6163	+	int r = this.basis;
6164	+	for (int i = baseIndex, f, h; batch > 0 &&
6165	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6166	+	addToPendingCount(1);
6167	+	(rights = new MapReduceKeysToIntTask<K,V>
6168	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6169	+	rights, transformer, r, reducer)).fork();
6170	+	}
6171	+	for (Node<K,V> p; (p = advance()) != null; )
6172	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6173	+	result = r;
6174	+	CountedCompleter<?> c;
6175	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6176	+	@SuppressWarnings("unchecked")
6177	+	MapReduceKeysToIntTask<K,V>
6178	+	t = (MapReduceKeysToIntTask<K,V>)c,
6179	+	s = t.rights;
6180	+	while (s != null) {
6181	+	t.result = reducer.applyAsInt(t.result, s.result);
6182	+	s = t.rights = s.nextRight;
6183	+	}
6184	+	}
6185	+	}
6186	+	}
6187	+	}
6188	+
6189	+	@SuppressWarnings("serial")
6190	+	static final class MapReduceValuesToIntTask<K,V>
6191	+	extends BulkTask<K,V,Integer> {
6192	+	final ToIntFunction<? super V> transformer;
6193	+	final IntBinaryOperator reducer;
6194	+	final int basis;
6195	+	int result;
6196	+	MapReduceValuesToIntTask<K,V> rights, nextRight;
6197	+	MapReduceValuesToIntTask
6198	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6199	+	MapReduceValuesToIntTask<K,V> nextRight,
6200	+	ToIntFunction<? super V> transformer,
6201	+	int basis,
6202	+	IntBinaryOperator reducer) {
6203	+	super(p, b, i, f, t); this.nextRight = nextRight;
6204	+	this.transformer = transformer;
6205	+	this.basis = basis; this.reducer = reducer;
6206	+	}
6207	+	public final Integer getRawResult() { return result; }
6208	+	public final void compute() {
6209	+	final ToIntFunction<? super V> transformer;
6210	+	final IntBinaryOperator reducer;
6211	+	if ((transformer = this.transformer) != null &&
6212	+	(reducer = this.reducer) != null) {
6213	+	int r = this.basis;
6214	+	for (int i = baseIndex, f, h; batch > 0 &&
6215	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6216	+	addToPendingCount(1);
6217	+	(rights = new MapReduceValuesToIntTask<K,V>
6218	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6219	+	rights, transformer, r, reducer)).fork();
6220	+	}
6221	+	for (Node<K,V> p; (p = advance()) != null; )
6222	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6223	+	result = r;
6224	+	CountedCompleter<?> c;
6225	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6226	+	@SuppressWarnings("unchecked")
6227	+	MapReduceValuesToIntTask<K,V>
6228	+	t = (MapReduceValuesToIntTask<K,V>)c,
6229	+	s = t.rights;
6230	+	while (s != null) {
6231	+	t.result = reducer.applyAsInt(t.result, s.result);
6232	+	s = t.rights = s.nextRight;
6233	+	}
6234	+	}
6235	+	}
6236	+	}
6237	+	}
6238	+
6239	+	@SuppressWarnings("serial")
6240	+	static final class MapReduceEntriesToIntTask<K,V>
6241	+	extends BulkTask<K,V,Integer> {
6242	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6243	+	final IntBinaryOperator reducer;
6244	+	final int basis;
6245	+	int result;
6246	+	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6247	+	MapReduceEntriesToIntTask
6248	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6249	+	MapReduceEntriesToIntTask<K,V> nextRight,
6250	+	ToIntFunction<Map.Entry<K,V>> transformer,
6251	+	int basis,
6252	+	IntBinaryOperator reducer) {
6253	+	super(p, b, i, f, t); this.nextRight = nextRight;
6254	+	this.transformer = transformer;
6255	+	this.basis = basis; this.reducer = reducer;
6256	+	}
6257	+	public final Integer getRawResult() { return result; }
6258	+	public final void compute() {
6259	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6260	+	final IntBinaryOperator reducer;
6261	+	if ((transformer = this.transformer) != null &&
6262	+	(reducer = this.reducer) != null) {
6263	+	int r = this.basis;
6264	+	for (int i = baseIndex, f, h; batch > 0 &&
6265	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6266	+	addToPendingCount(1);
6267	+	(rights = new MapReduceEntriesToIntTask<K,V>
6268	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6269	+	rights, transformer, r, reducer)).fork();
6270	+	}
6271	+	for (Node<K,V> p; (p = advance()) != null; )
6272	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6273	+	result = r;
6274	+	CountedCompleter<?> c;
6275	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6276	+	@SuppressWarnings("unchecked")
6277	+	MapReduceEntriesToIntTask<K,V>
6278	+	t = (MapReduceEntriesToIntTask<K,V>)c,
6279	+	s = t.rights;
6280	+	while (s != null) {
6281	+	t.result = reducer.applyAsInt(t.result, s.result);
6282	+	s = t.rights = s.nextRight;
6283	+	}
6284	+	}
6285	+	}
6286	+	}
6287	+	}
6288	+
6289	+	@SuppressWarnings("serial")
6290	+	static final class MapReduceMappingsToIntTask<K,V>
6291	+	extends BulkTask<K,V,Integer> {
6292	+	final ToIntBiFunction<? super K, ? super V> transformer;
6293	+	final IntBinaryOperator reducer;
6294	+	final int basis;
6295	+	int result;
6296	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6297	+	MapReduceMappingsToIntTask
6298	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6299	+	MapReduceMappingsToIntTask<K,V> nextRight,
6300	+	ToIntBiFunction<? super K, ? super V> transformer,
6301	+	int basis,
6302	+	IntBinaryOperator reducer) {
6303	+	super(p, b, i, f, t); this.nextRight = nextRight;
6304	+	this.transformer = transformer;
6305	+	this.basis = basis; this.reducer = reducer;
6306	+	}
6307	+	public final Integer getRawResult() { return result; }
6308	+	public final void compute() {
6309	+	final ToIntBiFunction<? super K, ? super V> transformer;
6310	+	final IntBinaryOperator reducer;
6311	+	if ((transformer = this.transformer) != null &&
6312	+	(reducer = this.reducer) != null) {
6313	+	int r = this.basis;
6314	+	for (int i = baseIndex, f, h; batch > 0 &&
6315	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6316	+	addToPendingCount(1);
6317	+	(rights = new MapReduceMappingsToIntTask<K,V>
6318	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6319	+	rights, transformer, r, reducer)).fork();
6320	+	}
6321	+	for (Node<K,V> p; (p = advance()) != null; )
6322	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6323	+	result = r;
6324	+	CountedCompleter<?> c;
6325	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6326	+	@SuppressWarnings("unchecked")
6327	+	MapReduceMappingsToIntTask<K,V>
6328	+	t = (MapReduceMappingsToIntTask<K,V>)c,
6329	+	s = t.rights;
6330	+	while (s != null) {
6331	+	t.result = reducer.applyAsInt(t.result, s.result);
6332	+	s = t.rights = s.nextRight;
6333	+	}
6334	+	}
6335	+	}
6336	+	}
6337	+	}
6338	+
6339	+	// Unsafe mechanics
6340	+	private static final Unsafe U = Unsafe.getUnsafe();
6341	+	private static final long SIZECTL;
6342	+	private static final long TRANSFERINDEX;
6343	+	private static final long BASECOUNT;
6344	+	private static final long CELLSBUSY;
6345	+	private static final long CELLVALUE;
6346	+	private static final int ABASE;
6347	+	private static final int ASHIFT;
6348	+
6349	+	static {
6350	+	try {
6351	+	SIZECTL = U.objectFieldOffset
6352	+	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6353	+	TRANSFERINDEX = U.objectFieldOffset
6354	+	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6355	+	BASECOUNT = U.objectFieldOffset
6356	+	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6357	+	CELLSBUSY = U.objectFieldOffset
6358	+	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6359	+
6360	+	CELLVALUE = U.objectFieldOffset
6361	+	(CounterCell.class.getDeclaredField("value"));
6362	+
6363	+	ABASE = U.arrayBaseOffset(Node[].class);
6364	+	int scale = U.arrayIndexScale(Node[].class);
6365	+	if ((scale & (scale - 1)) != 0)
6366	+	throw new Error("array index scale not a power of two");
6367	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6368	+	} catch (ReflectiveOperationException e) {
6369	+	throw new Error(e);
6370	+	}
6371	+
6372	+	// Reduce the risk of rare disastrous classloading in first call to
6373	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6374	+	Class<?> ensureLoaded = LockSupport.class;
6375	+	}
6376		}

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