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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.36 by dl, Sat Dec 27 19:26:25 2003 UTC vs.
Revision 1.318 by jsr166, Sat Aug 10 16:48:05 2019 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
66	<	* {@link ConcurrentModificationException}.  However, iterators are
67	<	* designed to be used by only one thread at a time.
68	<	*
69	<	* <p> The allowed concurrency among update operations is guided by
70	<	* the optional <tt>concurrencyLevel</tt> constructor argument
71	<	* (default 16), which is used as a hint for internal sizing.  The
72	<	* table is internally partitioned to try to permit the indicated
73	<	* number of concurrent updates without contention. Because placement
74	<	* in hash tables is essentially random, the actual concurrency will
75	<	* vary.  Ideally, you should choose a value to accommodate as many
76	<	* threads as will ever concurrently modify the table. Using a
77	<	* significantly higher value than you need can waste space and time,
78	<	* and a significantly lower value can lead to thread contention. But
79	<	* overestimates and underestimates within an order of magnitude do
80	<	* not usually have much noticeable impact. A value of one is
81	<	* appropriate when it is known that only one thread will modify
82	<	* and all others will only read.
83	<	*
84	<	* <p>This class implements all of the <em>optional</em> methods
85	<	* of the {@link Map} and {@link Iterator} interfaces.
86	<	*
87	<	* <p> Like {@link java.util.Hashtable} but unlike {@link
88	<	* java.util.HashMap}, this class does NOT allow <tt>null</tt> to be
89	<	* used as a key or value.
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>A ConcurrentHashMap can be used as a scalable frequency map (a
106	>	* form of histogram or multiset) by using {@link
107	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
108	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
109	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
110	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
111	>	*
112	>	* <p>This class and its views and iterators implement all of the
113	>	* <em>optional</em> methods of the {@link Map} and {@link Iterator}
114	>	* interfaces.
115	>	*
116	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
117	>	* does <em>not</em> allow {@code null} to be used as a key or value.
118	>	*
119	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
120	>	* operations that, unlike most {@link Stream} methods, are designed
121	>	* to be safely, and often sensibly, applied even with maps that are
122	>	* being concurrently updated by other threads; for example, when
123	>	* computing a snapshot summary of the values in a shared registry.
124	>	* There are three kinds of operation, each with four forms, accepting
125	>	* functions with keys, values, entries, and (key, value) pairs as
126	>	* arguments and/or return values. Because the elements of a
127	>	* ConcurrentHashMap are not ordered in any particular way, and may be
128	>	* processed in different orders in different parallel executions, the
129	>	* correctness of supplied functions should not depend on any
130	>	* ordering, or on any other objects or values that may transiently
131	>	* change while computation is in progress; and except for forEach
132	>	* actions, should ideally be side-effect-free. Bulk operations on
133	>	* {@link 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}/java.base/java/util/package-summary.html#CollectionsFramework">
228	>	* Java Collections Framework</a>.
229		*
230		* @since 1.5
231		* @author Doug Lea
232		* @param <K> the type of keys maintained by this map
233	<	* @param <V> the type of mapped values
233	>	* @param <V> the type of mapped values
234		*/
235	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
236	<	implements ConcurrentMap<K, V>, Cloneable, Serializable {
235	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
236	>	implements ConcurrentMap<K,V>, Serializable {
237		private static final long serialVersionUID = 7249069246763182397L;
238
239		/*
240	<	* The basic strategy is to subdivide the table among Segments,
241	<	* each of which itself is a concurrently readable hash table.
240	>	* Overview:
241	>	*
242	>	* The primary design goal of this hash table is to maintain
243	>	* concurrent readability (typically method get(), but also
244	>	* iterators and related methods) while minimizing update
245	>	* contention. Secondary goals are to keep space consumption about
246	>	* the same or better than java.util.HashMap, and to support high
247	>	* initial insertion rates on an empty table by many threads.
248	>	*
249	>	* This map usually acts as a binned (bucketed) hash table.  Each
250	>	* key-value mapping is held in a Node.  Most nodes are instances
251	>	* of the basic Node class with hash, key, value, and next
252	>	* fields. However, various subclasses exist: TreeNodes are
253	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
254	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
255	>	* of bins during resizing. ReservationNodes are used as
256	>	* placeholders while establishing values in computeIfAbsent and
257	>	* related methods.  The types TreeBin, ForwardingNode, and
258	>	* ReservationNode do not hold normal user keys, values, or
259	>	* hashes, and are readily distinguishable during search etc
260	>	* because they have negative hash fields and null key and value
261	>	* fields. (These special nodes are either uncommon or transient,
262	>	* so the impact of carrying around some unused fields is
263	>	* insignificant.)
264	>	*
265	>	* The table is lazily initialized to a power-of-two size upon the
266	>	* first insertion.  Each bin in the table normally contains a
267	>	* list of Nodes (most often, the list has only zero or one Node).
268	>	* Table accesses require volatile/atomic reads, writes, and
269	>	* CASes.  Because there is no other way to arrange this without
270	>	* adding further indirections, we use intrinsics
271	>	* (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 collectible as soon as they are no longer referenced by
360	>	* any reader thread that may be in the midst of concurrently
361	>	* traversing table.  Upon transfer, the old table bin contains
362	>	* only a special forwarding node (with hash field "MOVED") that
363	>	* contains the next table as its key. On encountering a
364	>	* forwarding node, access and update operations restart, using
365	>	* the new table.
366	>	*
367	>	* Each bin transfer requires its bin lock, which can stall
368	>	* waiting for locks while resizing. However, because other
369	>	* threads can join in and help resize rather than contend for
370	>	* locks, average aggregate waits become shorter as resizing
371	>	* progresses.  The transfer operation must also ensure that all
372	>	* accessible bins in both the old and new table are usable by any
373	>	* traversal.  This is arranged in part by proceeding from the
374	>	* last bin (table.length - 1) up towards the first.  Upon seeing
375	>	* a forwarding node, traversals (see class Traverser) arrange to
376	>	* move to the new table without revisiting nodes.  To ensure that
377	>	* no intervening nodes are skipped even when moved out of order,
378	>	* a stack (see class TableStack) is created on first encounter of
379	>	* a forwarding node during a traversal, to maintain its place if
380	>	* later processing the current table. The need for these
381	>	* save/restore mechanics is relatively rare, but when one
382	>	* forwarding node is encountered, typically many more will be.
383	>	* So Traversers use a simple caching scheme to avoid creating so
384	>	* many new TableStack nodes. (Thanks to Peter Levart for
385	>	* suggesting use of a stack here.)
386	>	*
387	>	* The traversal scheme also applies to partial traversals of
388	>	* ranges of bins (via an alternate Traverser constructor)
389	>	* to support partitioned aggregate operations.  Also, read-only
390	>	* operations give up if ever forwarded to a null table, which
391	>	* provides support for shutdown-style clearing, which is also not
392	>	* currently implemented.
393	>	*
394	>	* Lazy table initialization minimizes footprint until first use,
395	>	* and also avoids resizings when the first operation is from a
396	>	* putAll, constructor with map argument, or deserialization.
397	>	* These cases attempt to override the initial capacity settings,
398	>	* but harmlessly fail to take effect in cases of races.
399	>	*
400	>	* The element count is maintained using a specialization of
401	>	* LongAdder. We need to incorporate a specialization rather than
402	>	* just use a LongAdder in order to access implicit
403	>	* contention-sensing that leads to creation of multiple
404	>	* CounterCells.  The counter mechanics avoid contention on
405	>	* updates but can encounter cache thrashing if read too
406	>	* frequently during concurrent access. To avoid reading so often,
407	>	* resizing under contention is attempted only upon adding to a
408	>	* bin already holding two or more nodes. Under uniform hash
409	>	* distributions, the probability of this occurring at threshold
410	>	* is around 13%, meaning that only about 1 in 8 puts check
411	>	* threshold (and after resizing, many fewer do so).
412	>	*
413	>	* TreeBins use a special form of comparison for search and
414	>	* related operations (which is the main reason we cannot use
415	>	* existing collections such as TreeMaps). TreeBins contain
416	>	* Comparable elements, but may contain others, as well as
417	>	* elements that are Comparable but not necessarily Comparable for
418	>	* the same T, so we cannot invoke compareTo among them. To handle
419	>	* this, the tree is ordered primarily by hash value, then by
420	>	* Comparable.compareTo order if applicable.  On lookup at a node,
421	>	* if elements are not comparable or compare as 0 then both left
422	>	* and right children may need to be searched in the case of tied
423	>	* hash values. (This corresponds to the full list search that
424	>	* would be necessary if all elements were non-Comparable and had
425	>	* tied hashes.) On insertion, to keep a total ordering (or as
426	>	* close as is required here) across rebalancings, we compare
427	>	* classes and identityHashCodes as tie-breakers. The red-black
428	>	* balancing code is updated from pre-jdk-collections
429	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
430	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
431	>	* Algorithms" (CLR).
432	>	*
433	>	* TreeBins also require an additional locking mechanism.  While
434	>	* list traversal is always possible by readers even during
435	>	* updates, tree traversal is not, mainly because of tree-rotations
436	>	* that may change the root node and/or its linkages.  TreeBins
437	>	* include a simple read-write lock mechanism parasitic on the
438	>	* main bin-synchronization strategy: Structural adjustments
439	>	* associated with an insertion or removal are already bin-locked
440	>	* (and so cannot conflict with other writers) but must wait for
441	>	* ongoing readers to finish. Since there can be only one such
442	>	* waiter, we use a simple scheme using a single "waiter" field to
443	>	* block writers.  However, readers need never block.  If the root
444	>	* lock is held, they proceed along the slow traversal path (via
445	>	* next-pointers) until the lock becomes available or the list is
446	>	* exhausted, whichever comes first. These cases are not fast, but
447	>	* maximize aggregate expected throughput.
448	>	*
449	>	* Maintaining API and serialization compatibility with previous
450	>	* versions of this class introduces several oddities. Mainly: We
451	>	* leave untouched but unused constructor arguments referring to
452	>	* concurrencyLevel. We accept a loadFactor constructor argument,
453	>	* but apply it only to initial table capacity (which is the only
454	>	* time that we can guarantee to honor it.) We also declare an
455	>	* unused "Segment" class that is instantiated in minimal form
456	>	* only when serializing.
457	>	*
458	>	* Also, solely for compatibility with previous versions of this
459	>	* class, it extends AbstractMap, even though all of its methods
460	>	* are overridden, so it is just useless baggage.
461	>	*
462	>	* This file is organized to make things a little easier to follow
463	>	* while reading than they might otherwise: First the main static
464	>	* declarations and utilities, then fields, then main public
465	>	* methods (with a few factorings of multiple public methods into
466	>	* internal ones), then sizing methods, trees, traversers, and
467	>	* bulk operations.
468		*/
469
470		/* ---------------- Constants -------------- */
471
472		/**
473	<	* The default initial number of table slots for this table.
474	<	* Used when not otherwise specified in constructor.
473	>	* The largest possible table capacity.  This value must be
474	>	* exactly 1<<30 to stay within Java array allocation and indexing
475	>	* bounds for power of two table sizes, and is further required
476	>	* because the top two bits of 32bit hash fields are used for
477	>	* control purposes.
478		*/
479	<	private static int DEFAULT_INITIAL_CAPACITY = 16;
479	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
480
481		/**
482	<	* The maximum capacity, used if a higher value is implicitly
483	<	* specified by either of the constructors with arguments.  MUST
87	<	* be a power of two <= 1<<30 to ensure that entries are indexible
88	<	* using ints.
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 int MAXIMUM_CAPACITY = 1 << 30;
485	>	private static final int DEFAULT_CAPACITY = 16;
486
487		/**
488	<	* The default load factor for this table.  Used when not
489	<	* otherwise specified in constructor.
488	>	* The largest possible (non-power of two) array size.
489	>	* Needed by toArray and related methods.
490		*/
491	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
491	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
492
493		/**
494	<	* The default number of concurrency control segments.
495	<	**/
496	<	private static final int DEFAULT_SEGMENTS = 16;
494	>	* The default concurrency level for this table. Unused but
495	>	* defined for compatibility with previous versions of this class.
496	>	*/
497	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
498
499		/**
500	<	* The maximum number of segments to allow; used to bound ctor 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	<	private static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
506	>	private static final float LOAD_FACTOR = 0.75f;
507	>
508	>	/**
509	>	* The bin count threshold for using a tree rather than list for a
510	>	* bin.  Bins are converted to trees when adding an element to a
511	>	* bin with at least this many nodes. The value must be greater
512	>	* than 2, and should be at least 8 to mesh with assumptions in
513	>	* tree removal about conversion back to plain bins upon
514	>	* shrinkage.
515	>	*/
516	>	static final int TREEIFY_THRESHOLD = 8;
517	>
518	>	/**
519	>	* The bin count threshold for untreeifying a (split) bin during a
520	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
521	>	* most 6 to mesh with shrinkage detection under removal.
522	>	*/
523	>	static final int UNTREEIFY_THRESHOLD = 6;
524	>
525	>	/**
526	>	* The smallest table capacity for which bins may be treeified.
527	>	* (Otherwise the table is resized if too many nodes in a bin.)
528	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
529	>	* conflicts between resizing and treeification thresholds.
530	>	*/
531	>	static final int MIN_TREEIFY_CAPACITY = 64;
532	>
533	>	/**
534	>	* Minimum number of rebinnings per transfer step. Ranges are
535	>	* subdivided to allow multiple resizer threads.  This value
536	>	* serves as a lower bound to avoid resizers encountering
537	>	* excessive memory contention.  The value should be at least
538	>	* DEFAULT_CAPACITY.
539	>	*/
540	>	private static final int MIN_TRANSFER_STRIDE = 16;
541	>
542	>	/**
543	>	* The number of bits used for generation stamp in sizeCtl.
544	>	* Must be at least 6 for 32bit arrays.
545	>	*/
546	>	private static final int RESIZE_STAMP_BITS = 16;
547	>
548	>	/**
549	>	* The maximum number of threads that can help resize.
550	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
551	>	*/
552	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
553	>
554	>	/**
555	>	* The bit shift for recording size stamp in sizeCtl.
556	>	*/
557	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
558	>
559	>	/*
560	>	* Encodings for Node hash fields. See above for explanation.
561	>	*/
562	>	static final int MOVED     = -1; // hash for forwarding nodes
563	>	static final int TREEBIN   = -2; // hash for roots of trees
564	>	static final int RESERVED  = -3; // hash for transient reservations
565	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
566	>
567	>	/** Number of CPUS, to place bounds on some sizings */
568	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
569	>
570	>	/**
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 class Node<K,V> implements Map.Entry<K,V> {
597	>	final int hash;
598	>	final K key;
599	>	volatile V val;
600	>	volatile Node<K,V> next;
601	>
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;
611	>	}
612	>
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	>	* 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 int spread(int h) {
668	>	return (h ^ (h >>> 16)) & HASH_BITS;
669	>	}
670	>
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 = -1 >>> Integer.numberOfLeadingZeros(c - 1);
677	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
678	>	}
679	>
680	>	/**
681	>	* Returns x's Class if it is of the form "class C implements
682	>	* Comparable<C>", else null.
683	>	*/
684	>	static Class<?> comparableClassFor(Object x) {
685	>	if (x instanceof Comparable) {
686	>	Class<?> c; Type[] ts, as; ParameterizedType p;
687	>	if ((c = x.getClass()) == String.class) // bypass checks
688	>	return c;
689	>	if ((ts = c.getGenericInterfaces()) != null) {
690	>	for (Type t : ts) {
691	>	if ((t instanceof ParameterizedType) &&
692	>	((p = (ParameterizedType)t).getRawType() ==
693	>	Comparable.class) &&
694	>	(as = p.getActualTypeArguments()) != null &&
695	>	as.length == 1 && as[0] == c) // type arg is c
696	>	return c;
697	>	}
698	>	}
699	>	}
700	>	return null;
701	>	}
702	>
703	>	/**
704	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
705	>	* class), else 0.
706	>	*/
707	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
708	>	static int compareComparables(Class<?> kc, Object k, Object x) {
709	>	return (x == null || x.getClass() != kc ? 0 :
710	>	((Comparable)k).compareTo(x));
711	>	}
712	>
713	>	/* ---------------- Table element access -------------- */
714	>
715	>	/*
716	>	* Atomic access methods are used for table elements as well as
717	>	* elements of in-progress next table while resizing.  All uses of
718	>	* the tab arguments must be null checked by callers.  All callers
719	>	* also paranoically precheck that tab's length is not zero (or an
720	>	* equivalent check), thus ensuring that any index argument taking
721	>	* the form of a hash value anded with (length - 1) is a valid
722	>	* index.  Note that, to be correct wrt arbitrary concurrency
723	>	* errors by users, these checks must operate on local variables,
724	>	* which accounts for some odd-looking inline assignments below.
725	>	* Note that calls to setTabAt always occur within locked regions,
726	>	* and so require only release ordering.
727	>	*/
728	>
729	>	@SuppressWarnings("unchecked")
730	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
731	>	return (Node<K,V>)U.getObjectAcquire(tab, ((long)i << ASHIFT) + ABASE);
732	>	}
733	>
734	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
735	>	Node<K,V> c, Node<K,V> v) {
736	>	return U.compareAndSetObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
737	>	}
738	>
739	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
740	>	U.putObjectRelease(tab, ((long)i << ASHIFT) + ABASE, v);
741	>	}
742
743		/* ---------------- Fields -------------- */
744
745		/**
746	<	* Mask value for indexing into segments. The upper bits of a
747	<	* key's hash code are used to choose the segment.
748	<	**/
749	<	private final int segmentMask;
746	>	* The array of bins. Lazily initialized upon first insertion.
747	>	* Size is always a power of two. Accessed directly by iterators.
748	>	*/
749	>	transient volatile Node<K,V>[] table;
750
751		/**
752	<	* Shift value for indexing within segments.
753	<	**/
754	<	private final int segmentShift;
752	>	* The next table to use; non-null only while resizing.
753	>	*/
754	>	private transient volatile Node<K,V>[] nextTable;
755
756		/**
757	<	* The segments, each of which is a specialized hash table
757	>	* Base counter value, used mainly when there is no contention,
758	>	* but also as a fallback during table initialization
759	>	* races. Updated via CAS.
760		*/
761	<	private final Segment[] segments;
761	>	private transient volatile long baseCount;
762
763	<	private transient Set<K> keySet;
764	<	private transient Set<Map.Entry<K,V>> entrySet;
765	<	private transient Collection<V> values;
763	>	/**
764	>	* Table initialization and resizing control.  When negative, the
765	>	* table is being initialized or resized: -1 for initialization,
766	>	* else -(1 + the number of active resizing threads).  Otherwise,
767	>	* when table is null, holds the initial table size to use upon
768	>	* creation, or 0 for default. After initialization, holds the
769	>	* next element count value upon which to resize the table.
770	>	*/
771	>	private transient volatile int sizeCtl;
772
773	<	/* ---------------- Small Utilities -------------- */
773	>	/**
774	>	* The next table index (plus one) to split while resizing.
775	>	*/
776	>	private transient volatile int transferIndex;
777
778		/**
779	<	* Return a hash code for non-null Object x.
134	<	* Uses the same hash code spreader as most other j.u hash tables.
135	<	* @param x the object serving as a key
136	<	* @return the hash code
779	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
780		*/
781	<	private static int hash(Object x) {
782	<	int h = x.hashCode();
783	<	h += ~(h << 9);
784	<	h ^=  (h >>> 14);
785	<	h +=  (h << 4);
786	<	h ^=  (h >>> 10);
787	<	return h;
781	>	private transient volatile int cellsBusy;
782	>
783	>	/**
784	>	* Table of counter cells. When non-null, size is a power of 2.
785	>	*/
786	>	private transient volatile CounterCell[] counterCells;
787	>
788	>	// views
789	>	private transient KeySetView<K,V> keySet;
790	>	private transient ValuesView<K,V> values;
791	>	private transient EntrySetView<K,V> entrySet;
792	>
793	>
794	>	/* ---------------- Public operations -------------- */
795	>
796	>	/**
797	>	* Creates a new, empty map with the default initial table size (16).
798	>	*/
799	>	public ConcurrentHashMap() {
800		}
801
802		/**
803	<	* Return the segment that should be used for key with given hash
803	>	* Creates a new, empty map with an initial table size
804	>	* accommodating the specified number of elements without the need
805	>	* to dynamically resize.
806	>	*
807	>	* @param initialCapacity The implementation performs internal
808	>	* sizing to accommodate this many elements.
809	>	* @throws IllegalArgumentException if the initial capacity of
810	>	* elements is negative
811		*/
812	<	private Segment<K,V> segmentFor(int hash) {
813	<	return (Segment<K,V>) segments[(hash >>> segmentShift) & segmentMask];
812	>	public ConcurrentHashMap(int initialCapacity) {
813	>	this(initialCapacity, LOAD_FACTOR, 1);
814		}
815
816	<	/* ---------------- Inner Classes -------------- */
816	>	/**
817	>	* Creates a new map with the same mappings as the given map.
818	>	*
819	>	* @param m the map
820	>	*/
821	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
822	>	this.sizeCtl = DEFAULT_CAPACITY;
823	>	putAll(m);
824	>	}
825
826		/**
827	<	* Segments are specialized versions of hash tables.  This
828	<	* subclasses from ReentrantLock opportunistically, just to
829	<	* simplify some locking and avoid separate construction.
830	<	**/
831	<	private static final class Segment<K,V> extends ReentrantLock implements Serializable {
832	<	/*
833	<	* Segments maintain a table of entry lists that are ALWAYS
834	<	* kept in a consistent state, so can be read without locking.
835	<	* Next fields of nodes are immutable (final).  All list
836	<	* additions are performed at the front of each bin. This
837	<	* makes it easy to check changes, and also fast to traverse.
838	<	* When nodes would otherwise be changed, new nodes are
839	<	* created to replace them. This works well for hash tables
840	<	* since the bin lists tend to be short. (The average length
841	<	* is less than two for the default load factor threshold.)
842	<	*
843	<	* Read operations can thus proceed without locking, but rely
174	<	* on a memory barrier to ensure that completed write
175	<	* operations performed by other threads are
176	<	* noticed. Conveniently, the "count" field, tracking the
177	<	* number of elements, can also serve as the volatile variable
178	<	* providing proper read/write barriers. This is convenient
179	<	* because this field needs to be read in many read operations
180	<	* anyway.
181	<	*
182	<	* Implementors note. The basic rules for all this are:
183	<	*
184	<	*   - All unsynchronized read operations must first read the
185	<	*     "count" field, and should not look at table entries if
186	<	*     it is 0.
187	<	*
188	<	*   - All synchronized write operations should write to
189	<	*     the "count" field after updating. The operations must not
190	<	*     take any action that could even momentarily cause
191	<	*     a concurrent read operation to see inconsistent
192	<	*     data. This is made easier by the nature of the read
193	<	*     operations in Map. For example, no operation
194	<	*     can reveal that the table has grown but the threshold
195	<	*     has not yet been updated, so there are no atomicity
196	<	*     requirements for this with respect to reads.
197	<	*
198	<	* As a guide, all critical volatile reads and writes are marked
199	<	* in code comments.
200	<	*/
827	>	* Creates a new, empty map with an initial table size based on
828	>	* the given number of elements ({@code initialCapacity}) and
829	>	* initial table density ({@code loadFactor}).
830	>	*
831	>	* @param initialCapacity the initial capacity. The implementation
832	>	* performs internal sizing to accommodate this many elements,
833	>	* given the specified load factor.
834	>	* @param loadFactor the load factor (table density) for
835	>	* establishing the initial table size
836	>	* @throws IllegalArgumentException if the initial capacity of
837	>	* elements is negative or the load factor is nonpositive
838	>	*
839	>	* @since 1.6
840	>	*/
841	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
842	>	this(initialCapacity, loadFactor, 1);
843	>	}
844
845	<	private static final long serialVersionUID = 2249069246763182397L;
845	>	/**
846	>	* Creates a new, empty map with an initial table size based on
847	>	* the given number of elements ({@code initialCapacity}), initial
848	>	* table density ({@code loadFactor}), and number of concurrently
849	>	* updating threads ({@code concurrencyLevel}).
850	>	*
851	>	* @param initialCapacity the initial capacity. The implementation
852	>	* performs internal sizing to accommodate this many elements,
853	>	* given the specified load factor.
854	>	* @param loadFactor the load factor (table density) for
855	>	* establishing the initial table size
856	>	* @param concurrencyLevel the estimated number of concurrently
857	>	* updating threads. The implementation may use this value as
858	>	* a sizing hint.
859	>	* @throws IllegalArgumentException if the initial capacity is
860	>	* negative or the load factor or concurrencyLevel are
861	>	* nonpositive
862	>	*/
863	>	public ConcurrentHashMap(int initialCapacity,
864	>	float loadFactor, int concurrencyLevel) {
865	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
866	>	throw new IllegalArgumentException();
867	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
868	>	initialCapacity = concurrencyLevel;   // as estimated threads
869	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
870	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
871	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
872	>	this.sizeCtl = cap;
873	>	}
874
875	<	/**
205	<	* The number of elements in this segment's region.
206	<	**/
207	<	transient volatile int count;
875	>	// Original (since JDK1.2) Map methods
876
877	<	/**
878	<	* Number of updates; used for checking lack of modifications
879	<	* in bulk-read methods.
880	<	*/
881	<	transient int modCount;
877	>	/**
878	>	* {@inheritDoc}
879	>	*/
880	>	public int size() {
881	>	long n = sumCount();
882	>	return ((n < 0L) ? 0 :
883	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
884	>	(int)n);
885	>	}
886
887	<	/**
888	<	* The table is rehashed when its size exceeds this threshold.
889	<	* (The value of this field is always (int)(capacity *
890	<	* loadFactor).)
891	<	*/
892	<	private transient int threshold;
887	>	/**
888	>	* {@inheritDoc}
889	>	*/
890	>	public boolean isEmpty() {
891	>	return sumCount() <= 0L; // ignore transient negative values
892	>	}
893
894	<	/**
895	<	* The per-segment table
896	<	*/
897	<	transient HashEntry[] table;
894	>	/**
895	>	* Returns the value to which the specified key is mapped,
896	>	* or {@code null} if this map contains no mapping for the key.
897	>	*
898	>	* <p>More formally, if this map contains a mapping from a key
899	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
900	>	* then this method returns {@code v}; otherwise it returns
901	>	* {@code null}.  (There can be at most one such mapping.)
902	>	*
903	>	* @throws NullPointerException if the specified key is null
904	>	*/
905	>	public V get(Object key) {
906	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
907	>	int h = spread(key.hashCode());
908	>	if ((tab = table) != null && (n = tab.length) > 0 &&
909	>	(e = tabAt(tab, (n - 1) & h)) != null) {
910	>	if ((eh = e.hash) == h) {
911	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
912	>	return e.val;
913	>	}
914	>	else if (eh < 0)
915	>	return (p = e.find(h, key)) != null ? p.val : null;
916	>	while ((e = e.next) != null) {
917	>	if (e.hash == h &&
918	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
919	>	return e.val;
920	>	}
921	>	}
922	>	return null;
923	>	}
924
925	<	/**
926	<	* The load factor for the hash table.  Even though this value
927	<	* is same for all segments, it is replicated to avoid needing
928	<	* links to outer object.
929	<	* @serial
930	<	*/
931	<	private final float loadFactor;
925	>	/**
926	>	* Tests if the specified object is a key in this table.
927	>	*
928	>	* @param  key possible key
929	>	* @return {@code true} if and only if the specified object
930	>	*         is a key in this table, as determined by the
931	>	*         {@code equals} method; {@code false} otherwise
932	>	* @throws NullPointerException if the specified key is null
933	>	*/
934	>	public boolean containsKey(Object key) {
935	>	return get(key) != null;
936	>	}
937
938	<	Segment(int initialCapacity, float lf) {
939	<	loadFactor = lf;
940	<	setTable(new HashEntry[initialCapacity]);
938	>	/**
939	>	* Returns {@code true} if this map maps one or more keys to the
940	>	* specified value. Note: This method may require a full traversal
941	>	* of the map, and is much slower than method {@code containsKey}.
942	>	*
943	>	* @param value value whose presence in this map is to be tested
944	>	* @return {@code true} if this map maps one or more keys to the
945	>	*         specified value
946	>	* @throws NullPointerException if the specified value is null
947	>	*/
948	>	public boolean containsValue(Object value) {
949	>	if (value == null)
950	>	throw new NullPointerException();
951	>	Node<K,V>[] t;
952	>	if ((t = table) != null) {
953	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
954	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
955	>	V v;
956	>	if ((v = p.val) == value || (v != null && value.equals(v)))
957	>	return true;
958	>	}
959		}
960	+	return false;
961	+	}
962
963	<	/**
964	<	* Set table to new HashEntry array.
965	<	* Call only while holding lock or in constructor.
966	<	**/
967	<	private void setTable(HashEntry[] newTable) {
968	<	table = newTable;
969	<	threshold = (int)(newTable.length * loadFactor);
970	<	count = count; // write-volatile
963	>	/**
964	>	* Maps the specified key to the specified value in this table.
965	>	* Neither the key nor the value can be null.
966	>	*
967	>	* <p>The value can be retrieved by calling the {@code get} method
968	>	* with a key that is equal to the original key.
969	>	*
970	>	* @param key key with which the specified value is to be associated
971	>	* @param value value to be associated with the specified key
972	>	* @return the previous value associated with {@code key}, or
973	>	*         {@code null} if there was no mapping for {@code key}
974	>	* @throws NullPointerException if the specified key or value is null
975	>	*/
976	>	public V put(K key, V value) {
977	>	return putVal(key, value, false);
978	>	}
979	>
980	>	/** Implementation for put and putIfAbsent */
981	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
982	>	if (key == null || value == null) throw new NullPointerException();
983	>	int hash = spread(key.hashCode());
984	>	int binCount = 0;
985	>	for (Node<K,V>[] tab = table;;) {
986	>	Node<K,V> f; int n, i, fh; K fk; V fv;
987	>	if (tab == null || (n = tab.length) == 0)
988	>	tab = initTable();
989	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
990	>	if (casTabAt(tab, i, null, new Node<K,V>(hash, key, value)))
991	>	break;                   // no lock when adding to empty bin
992	>	}
993	>	else if ((fh = f.hash) == MOVED)
994	>	tab = helpTransfer(tab, f);
995	>	else if (onlyIfAbsent // check first node without acquiring lock
996	>	&& fh == hash
997	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
998	>	&& (fv = f.val) != null)
999	>	return fv;
1000	>	else {
1001	>	V oldVal = null;
1002	>	synchronized (f) {
1003	>	if (tabAt(tab, i) == f) {
1004	>	if (fh >= 0) {
1005	>	binCount = 1;
1006	>	for (Node<K,V> e = f;; ++binCount) {
1007	>	K ek;
1008	>	if (e.hash == hash &&
1009	>	((ek = e.key) == key ||
1010	>	(ek != null && key.equals(ek)))) {
1011	>	oldVal = e.val;
1012	>	if (!onlyIfAbsent)
1013	>	e.val = value;
1014	>	break;
1015	>	}
1016	>	Node<K,V> pred = e;
1017	>	if ((e = e.next) == null) {
1018	>	pred.next = new Node<K,V>(hash, key, value);
1019	>	break;
1020	>	}
1021	>	}
1022	>	}
1023	>	else if (f instanceof TreeBin) {
1024	>	Node<K,V> p;
1025	>	binCount = 2;
1026	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1027	>	value)) != null) {
1028	>	oldVal = p.val;
1029	>	if (!onlyIfAbsent)
1030	>	p.val = value;
1031	>	}
1032	>	}
1033	>	else if (f instanceof ReservationNode)
1034	>	throw new IllegalStateException("Recursive update");
1035	>	}
1036	>	}
1037	>	if (binCount != 0) {
1038	>	if (binCount >= TREEIFY_THRESHOLD)
1039	>	treeifyBin(tab, i);
1040	>	if (oldVal != null)
1041	>	return oldVal;
1042	>	break;
1043	>	}
1044	>	}
1045		}
1046	+	addCount(1L, binCount);
1047	+	return null;
1048	+	}
1049
1050	<	/* Specialized implementations of map methods */
1050	>	/**
1051	>	* Copies all of the mappings from the specified map to this one.
1052	>	* These mappings replace any mappings that this map had for any of the
1053	>	* keys currently in the specified map.
1054	>	*
1055	>	* @param m mappings to be stored in this map
1056	>	*/
1057	>	public void putAll(Map<? extends K, ? extends V> m) {
1058	>	tryPresize(m.size());
1059	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1060	>	putVal(e.getKey(), e.getValue(), false);
1061	>	}
1062
1063	<	V get(Object key, int hash) {
1064	<	if (count != 0) { // read-volatile
1065	<	HashEntry[] tab = table;
1066	<	int index = hash & (tab.length - 1);
1067	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
1068	<	while (e != null) {
1069	<	if (e.hash == hash && key.equals(e.key))
1070	<	return e.value;
1071	<	e = e.next;
1063	>	/**
1064	>	* Removes the key (and its corresponding value) from this map.
1065	>	* This method does nothing if the key is not in the map.
1066	>	*
1067	>	* @param  key the key that needs to be removed
1068	>	* @return the previous value associated with {@code key}, or
1069	>	*         {@code null} if there was no mapping for {@code key}
1070	>	* @throws NullPointerException if the specified key is null
1071	>	*/
1072	>	public V remove(Object key) {
1073	>	return replaceNode(key, null, null);
1074	>	}
1075	>
1076	>	/**
1077	>	* Implementation for the four public remove/replace methods:
1078	>	* Replaces node value with v, conditional upon match of cv if
1079	>	* non-null.  If resulting value is null, delete.
1080	>	*/
1081	>	final V replaceNode(Object key, V value, Object cv) {
1082	>	int hash = spread(key.hashCode());
1083	>	for (Node<K,V>[] tab = table;;) {
1084	>	Node<K,V> f; int n, i, fh;
1085	>	if (tab == null || (n = tab.length) == 0 ||
1086	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1087	>	break;
1088	>	else if ((fh = f.hash) == MOVED)
1089	>	tab = helpTransfer(tab, f);
1090	>	else {
1091	>	V oldVal = null;
1092	>	boolean validated = false;
1093	>	synchronized (f) {
1094	>	if (tabAt(tab, i) == f) {
1095	>	if (fh >= 0) {
1096	>	validated = true;
1097	>	for (Node<K,V> e = f, pred = null;;) {
1098	>	K ek;
1099	>	if (e.hash == hash &&
1100	>	((ek = e.key) == key ||
1101	>	(ek != null && key.equals(ek)))) {
1102	>	V ev = e.val;
1103	>	if (cv == null || cv == ev ||
1104	>	(ev != null && cv.equals(ev))) {
1105	>	oldVal = ev;
1106	>	if (value != null)
1107	>	e.val = value;
1108	>	else if (pred != null)
1109	>	pred.next = e.next;
1110	>	else
1111	>	setTabAt(tab, i, e.next);
1112	>	}
1113	>	break;
1114	>	}
1115	>	pred = e;
1116	>	if ((e = e.next) == null)
1117	>	break;
1118	>	}
1119	>	}
1120	>	else if (f instanceof TreeBin) {
1121	>	validated = true;
1122	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1123	>	TreeNode<K,V> r, p;
1124	>	if ((r = t.root) != null &&
1125	>	(p = r.findTreeNode(hash, key, null)) != null) {
1126	>	V pv = p.val;
1127	>	if (cv == null || cv == pv ||
1128	>	(pv != null && cv.equals(pv))) {
1129	>	oldVal = pv;
1130	>	if (value != null)
1131	>	p.val = value;
1132	>	else if (t.removeTreeNode(p))
1133	>	setTabAt(tab, i, untreeify(t.first));
1134	>	}
1135	>	}
1136	>	}
1137	>	else if (f instanceof ReservationNode)
1138	>	throw new IllegalStateException("Recursive update");
1139	>	}
1140	>	}
1141	>	if (validated) {
1142	>	if (oldVal != null) {
1143	>	if (value == null)
1144	>	addCount(-1L, -1);
1145	>	return oldVal;
1146	>	}
1147	>	break;
1148		}
1149		}
263	–	return null;
1150		}
1151	+	return null;
1152	+	}
1153
1154	<	boolean containsKey(Object key, int hash) {
1155	<	if (count != 0) { // read-volatile
1156	<	HashEntry[] tab = table;
1157	<	int index = hash & (tab.length - 1);
1158	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
1159	<	while (e != null) {
1160	<	if (e.hash == hash && key.equals(e.key))
1161	<	return true;
1162	<	e = e.next;
1154	>	/**
1155	>	* Removes all of the mappings from this map.
1156	>	*/
1157	>	public void clear() {
1158	>	long delta = 0L; // negative number of deletions
1159	>	int i = 0;
1160	>	Node<K,V>[] tab = table;
1161	>	while (tab != null && i < tab.length) {
1162	>	int fh;
1163	>	Node<K,V> f = tabAt(tab, i);
1164	>	if (f == null)
1165	>	++i;
1166	>	else if ((fh = f.hash) == MOVED) {
1167	>	tab = helpTransfer(tab, f);
1168	>	i = 0; // restart
1169	>	}
1170	>	else {
1171	>	synchronized (f) {
1172	>	if (tabAt(tab, i) == f) {
1173	>	Node<K,V> p = (fh >= 0 ? f :
1174	>	(f instanceof TreeBin) ?
1175	>	((TreeBin<K,V>)f).first : null);
1176	>	while (p != null) {
1177	>	--delta;
1178	>	p = p.next;
1179	>	}
1180	>	setTabAt(tab, i++, null);
1181	>	}
1182		}
1183		}
277	–	return false;
1184		}
1185	+	if (delta != 0L)
1186	+	addCount(delta, -1);
1187	+	}
1188	+
1189	+	/**
1190	+	* Returns a {@link Set} view of the keys contained in this map.
1191	+	* The set is backed by the map, so changes to the map are
1192	+	* reflected in the set, and vice-versa. The set supports element
1193	+	* removal, which removes the corresponding mapping from this map,
1194	+	* via the {@code Iterator.remove}, {@code Set.remove},
1195	+	* {@code removeAll}, {@code retainAll}, and {@code clear}
1196	+	* operations.  It does not support the {@code add} or
1197	+	* {@code addAll} operations.
1198	+	*
1199	+	* <p>The view's iterators and spliterators are
1200	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1201	+	*
1202	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1203	+	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1204	+	*
1205	+	* @return the set view
1206	+	*/
1207	+	public KeySetView<K,V> keySet() {
1208	+	KeySetView<K,V> ks;
1209	+	if ((ks = keySet) != null) return ks;
1210	+	return keySet = new KeySetView<K,V>(this, null);
1211	+	}
1212
1213	<	boolean containsValue(Object value) {
1214	<	if (count != 0) { // read-volatile
1215	<	HashEntry[] tab = table;
1216	<	int len = tab.length;
1217	<	for (int i = 0 ; i < len; i++)
1218	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i] ; e != null ; e = e.next)
1219	<	if (value.equals(e.value))
1220	<	return true;
1213	>	/**
1214	>	* Returns a {@link Collection} view of the values contained in this map.
1215	>	* The collection is backed by the map, so changes to the map are
1216	>	* reflected in the collection, and vice-versa.  The collection
1217	>	* supports element removal, which removes the corresponding
1218	>	* mapping from this map, via the {@code Iterator.remove},
1219	>	* {@code Collection.remove}, {@code removeAll},
1220	>	* {@code retainAll}, and {@code clear} operations.  It does not
1221	>	* support the {@code add} or {@code addAll} operations.
1222	>	*
1223	>	* <p>The view's iterators and spliterators are
1224	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1225	>	*
1226	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1227	>	* and {@link Spliterator#NONNULL}.
1228	>	*
1229	>	* @return the collection view
1230	>	*/
1231	>	public Collection<V> values() {
1232	>	ValuesView<K,V> vs;
1233	>	if ((vs = values) != null) return vs;
1234	>	return values = new ValuesView<K,V>(this);
1235	>	}
1236	>
1237	>	/**
1238	>	* Returns a {@link Set} view of the mappings contained in this map.
1239	>	* The set is backed by the map, so changes to the map are
1240	>	* reflected in the set, and vice-versa.  The set supports element
1241	>	* removal, which removes the corresponding mapping from the map,
1242	>	* via the {@code Iterator.remove}, {@code Set.remove},
1243	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1244	>	* operations.
1245	>	*
1246	>	* <p>The view's iterators and spliterators are
1247	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1248	>	*
1249	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1250	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1251	>	*
1252	>	* @return the set view
1253	>	*/
1254	>	public Set<Map.Entry<K,V>> entrySet() {
1255	>	EntrySetView<K,V> es;
1256	>	if ((es = entrySet) != null) return es;
1257	>	return entrySet = new EntrySetView<K,V>(this);
1258	>	}
1259	>
1260	>	/**
1261	>	* Returns the hash code value for this {@link Map}, i.e.,
1262	>	* the sum of, for each key-value pair in the map,
1263	>	* {@code key.hashCode() ^ value.hashCode()}.
1264	>	*
1265	>	* @return the hash code value for this map
1266	>	*/
1267	>	public int hashCode() {
1268	>	int h = 0;
1269	>	Node<K,V>[] t;
1270	>	if ((t = table) != null) {
1271	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1272	>	for (Node<K,V> p; (p = it.advance()) != null; )
1273	>	h += p.key.hashCode() ^ p.val.hashCode();
1274	>	}
1275	>	return h;
1276	>	}
1277	>
1278	>	/**
1279	>	* Returns a string representation of this map.  The string
1280	>	* representation consists of a list of key-value mappings (in no
1281	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1282	>	* mappings are separated by the characters {@code ", "} (comma
1283	>	* and space).  Each key-value mapping is rendered as the key
1284	>	* followed by an equals sign ("{@code =}") followed by the
1285	>	* associated value.
1286	>	*
1287	>	* @return a string representation of this map
1288	>	*/
1289	>	public String toString() {
1290	>	Node<K,V>[] t;
1291	>	int f = (t = table) == null ? 0 : t.length;
1292	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1293	>	StringBuilder sb = new StringBuilder();
1294	>	sb.append('{');
1295	>	Node<K,V> p;
1296	>	if ((p = it.advance()) != null) {
1297	>	for (;;) {
1298	>	K k = p.key;
1299	>	V v = p.val;
1300	>	sb.append(k == this ? "(this Map)" : k);
1301	>	sb.append('=');
1302	>	sb.append(v == this ? "(this Map)" : v);
1303	>	if ((p = it.advance()) == null)
1304	>	break;
1305	>	sb.append(',').append(' ');
1306	>	}
1307	>	}
1308	>	return sb.append('}').toString();
1309	>	}
1310	>
1311	>	/**
1312	>	* Compares the specified object with this map for equality.
1313	>	* Returns {@code true} if the given object is a map with the same
1314	>	* mappings as this map.  This operation may return misleading
1315	>	* results if either map is concurrently modified during execution
1316	>	* of this method.
1317	>	*
1318	>	* @param o object to be compared for equality with this map
1319	>	* @return {@code true} if the specified object is equal to this map
1320	>	*/
1321	>	public boolean equals(Object o) {
1322	>	if (o != this) {
1323	>	if (!(o instanceof Map))
1324	>	return false;
1325	>	Map<?,?> m = (Map<?,?>) o;
1326	>	Node<K,V>[] t;
1327	>	int f = (t = table) == null ? 0 : t.length;
1328	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1329	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1330	>	V val = p.val;
1331	>	Object v = m.get(p.key);
1332	>	if (v == null || (v != val && !v.equals(val)))
1333	>	return false;
1334	>	}
1335	>	for (Map.Entry<?,?> e : m.entrySet()) {
1336	>	Object mk, mv, v;
1337	>	if ((mk = e.getKey()) == null ||
1338	>	(mv = e.getValue()) == null ||
1339	>	(v = get(mk)) == null ||
1340	>	(mv != v && !mv.equals(v)))
1341	>	return false;
1342		}
289	–	return false;
1343		}
1344	+	return true;
1345	+	}
1346
1347	<	boolean replace(K key, int hash, V oldValue, V newValue) {
1348	<	lock();
1349	<	try {
1350	<	int c = count;
1351	<	HashEntry[] tab = table;
1352	<	int index = hash & (tab.length - 1);
1353	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1354	<	HashEntry<K,V> e = first;
1355	<	for (;;) {
1356	<	if (e == null)
1357	<	return false;
1358	<	if (e.hash == hash && key.equals(e.key))
1359	<	break;
1360	<	e = e.next;
1347	>	/**
1348	>	* Stripped-down version of helper class used in previous version,
1349	>	* declared for the sake of serialization compatibility.
1350	>	*/
1351	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1352	>	private static final long serialVersionUID = 2249069246763182397L;
1353	>	final float loadFactor;
1354	>	Segment(float lf) { this.loadFactor = lf; }
1355	>	}
1356	>
1357	>	/**
1358	>	* Saves this map to a stream (that is, serializes it).
1359	>	*
1360	>	* @param s the stream
1361	>	* @throws java.io.IOException if an I/O error occurs
1362	>	* @serialData
1363	>	* the serialized fields, followed by the key (Object) and value
1364	>	* (Object) for each key-value mapping, followed by a null pair.
1365	>	* The key-value mappings are emitted in no particular order.
1366	>	*/
1367	>	private void writeObject(java.io.ObjectOutputStream s)
1368	>	throws java.io.IOException {
1369	>	// For serialization compatibility
1370	>	// Emulate segment calculation from previous version of this class
1371	>	int sshift = 0;
1372	>	int ssize = 1;
1373	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1374	>	++sshift;
1375	>	ssize <<= 1;
1376	>	}
1377	>	int segmentShift = 32 - sshift;
1378	>	int segmentMask = ssize - 1;
1379	>	@SuppressWarnings("unchecked")
1380	>	Segment<K,V>[] segments = (Segment<K,V>[])
1381	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1382	>	for (int i = 0; i < segments.length; ++i)
1383	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1384	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1385	>	streamFields.put("segments", segments);
1386	>	streamFields.put("segmentShift", segmentShift);
1387	>	streamFields.put("segmentMask", segmentMask);
1388	>	s.writeFields();
1389	>
1390	>	Node<K,V>[] t;
1391	>	if ((t = table) != null) {
1392	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1393	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1394	>	s.writeObject(p.key);
1395	>	s.writeObject(p.val);
1396	>	}
1397	>	}
1398	>	s.writeObject(null);
1399	>	s.writeObject(null);
1400	>	}
1401	>
1402	>	/**
1403	>	* Reconstitutes this map from a stream (that is, deserializes it).
1404	>	* @param s the stream
1405	>	* @throws ClassNotFoundException if the class of a serialized object
1406	>	*         could not be found
1407	>	* @throws java.io.IOException if an I/O error occurs
1408	>	*/
1409	>	private void readObject(java.io.ObjectInputStream s)
1410	>	throws java.io.IOException, ClassNotFoundException {
1411	>	/*
1412	>	* To improve performance in typical cases, we create nodes
1413	>	* while reading, then place in table once size is known.
1414	>	* However, we must also validate uniqueness and deal with
1415	>	* overpopulated bins while doing so, which requires
1416	>	* specialized versions of putVal mechanics.
1417	>	*/
1418	>	sizeCtl = -1; // force exclusion for table construction
1419	>	s.defaultReadObject();
1420	>	long size = 0L;
1421	>	Node<K,V> p = null;
1422	>	for (;;) {
1423	>	@SuppressWarnings("unchecked")
1424	>	K k = (K) s.readObject();
1425	>	@SuppressWarnings("unchecked")
1426	>	V v = (V) s.readObject();
1427	>	if (k != null && v != null) {
1428	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1429	>	++size;
1430	>	}
1431	>	else
1432	>	break;
1433	>	}
1434	>	if (size == 0L)
1435	>	sizeCtl = 0;
1436	>	else {
1437	>	long ts = (long)(1.0 + size / LOAD_FACTOR);
1438	>	int n = (ts >= (long)MAXIMUM_CAPACITY) ?
1439	>	MAXIMUM_CAPACITY : tableSizeFor((int)ts);
1440	>	@SuppressWarnings("unchecked")
1441	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1442	>	int mask = n - 1;
1443	>	long added = 0L;
1444	>	while (p != null) {
1445	>	boolean insertAtFront;
1446	>	Node<K,V> next = p.next, first;
1447	>	int h = p.hash, j = h & mask;
1448	>	if ((first = tabAt(tab, j)) == null)
1449	>	insertAtFront = true;
1450	>	else {
1451	>	K k = p.key;
1452	>	if (first.hash < 0) {
1453	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1454	>	if (t.putTreeVal(h, k, p.val) == null)
1455	>	++added;
1456	>	insertAtFront = false;
1457	>	}
1458	>	else {
1459	>	int binCount = 0;
1460	>	insertAtFront = true;
1461	>	Node<K,V> q; K qk;
1462	>	for (q = first; q != null; q = q.next) {
1463	>	if (q.hash == h &&
1464	>	((qk = q.key) == k ||
1465	>	(qk != null && k.equals(qk)))) {
1466	>	insertAtFront = false;
1467	>	break;
1468	>	}
1469	>	++binCount;
1470	>	}
1471	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1472	>	insertAtFront = false;
1473	>	++added;
1474	>	p.next = first;
1475	>	TreeNode<K,V> hd = null, tl = null;
1476	>	for (q = p; q != null; q = q.next) {
1477	>	TreeNode<K,V> t = new TreeNode<K,V>
1478	>	(q.hash, q.key, q.val, null, null);
1479	>	if ((t.prev = tl) == null)
1480	>	hd = t;
1481	>	else
1482	>	tl.next = t;
1483	>	tl = t;
1484	>	}
1485	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1486	>	}
1487	>	}
1488	>	}
1489	>	if (insertAtFront) {
1490	>	++added;
1491	>	p.next = first;
1492	>	setTabAt(tab, j, p);
1493		}
1494	+	p = next;
1495	+	}
1496	+	table = tab;
1497	+	sizeCtl = n - (n >>> 2);
1498	+	baseCount = added;
1499	+	}
1500	+	}
1501
1502	<	V v = e.value;
309	<	if (v == null || !oldValue.equals(v))
310	<	return false;
1502	>	// ConcurrentMap methods
1503
1504	<	e.value = newValue;
1505	<	count = c; // write-volatile
1506	<	return true;
1507	<
1508	<	} finally {
1509	<	unlock();
1504	>	/**
1505	>	* {@inheritDoc}
1506	>	*
1507	>	* @return the previous value associated with the specified key,
1508	>	*         or {@code null} if there was no mapping for the key
1509	>	* @throws NullPointerException if the specified key or value is null
1510	>	*/
1511	>	public V putIfAbsent(K key, V value) {
1512	>	return putVal(key, value, true);
1513	>	}
1514	>
1515	>	/**
1516	>	* {@inheritDoc}
1517	>	*
1518	>	* @throws NullPointerException if the specified key is null
1519	>	*/
1520	>	public boolean remove(Object key, Object value) {
1521	>	if (key == null)
1522	>	throw new NullPointerException();
1523	>	return value != null && replaceNode(key, null, value) != null;
1524	>	}
1525	>
1526	>	/**
1527	>	* {@inheritDoc}
1528	>	*
1529	>	* @throws NullPointerException if any of the arguments are null
1530	>	*/
1531	>	public boolean replace(K key, V oldValue, V newValue) {
1532	>	if (key == null || oldValue == null || newValue == null)
1533	>	throw new NullPointerException();
1534	>	return replaceNode(key, newValue, oldValue) != null;
1535	>	}
1536	>
1537	>	/**
1538	>	* {@inheritDoc}
1539	>	*
1540	>	* @return the previous value associated with the specified key,
1541	>	*         or {@code null} if there was no mapping for the key
1542	>	* @throws NullPointerException if the specified key or value is null
1543	>	*/
1544	>	public V replace(K key, V value) {
1545	>	if (key == null || value == null)
1546	>	throw new NullPointerException();
1547	>	return replaceNode(key, value, null);
1548	>	}
1549	>
1550	>	// Overrides of JDK8+ Map extension method defaults
1551	>
1552	>	/**
1553	>	* Returns the value to which the specified key is mapped, or the
1554	>	* given default value if this map contains no mapping for the
1555	>	* key.
1556	>	*
1557	>	* @param key the key whose associated value is to be returned
1558	>	* @param defaultValue the value to return if this map contains
1559	>	* no mapping for the given key
1560	>	* @return the mapping for the key, if present; else the default value
1561	>	* @throws NullPointerException if the specified key is null
1562	>	*/
1563	>	public V getOrDefault(Object key, V defaultValue) {
1564	>	V v;
1565	>	return (v = get(key)) == null ? defaultValue : v;
1566	>	}
1567	>
1568	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1569	>	if (action == null) throw new NullPointerException();
1570	>	Node<K,V>[] t;
1571	>	if ((t = table) != null) {
1572	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1573	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1574	>	action.accept(p.key, p.val);
1575		}
1576		}
1577	+	}
1578
1579	<	V replace(K key, int hash, V newValue) {
1580	<	lock();
1581	<	try {
1582	<	int c = count;
1583	<	HashEntry[] tab = table;
1584	<	int index = hash & (tab.length - 1);
1585	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1586	<	HashEntry<K,V> e = first;
1587	<	for (;;) {
1588	<	if (e == null)
1589	<	return null;
1590	<	if (e.hash == hash && key.equals(e.key))
1579	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1580	>	if (function == null) throw new NullPointerException();
1581	>	Node<K,V>[] t;
1582	>	if ((t = table) != null) {
1583	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1584	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1585	>	V oldValue = p.val;
1586	>	for (K key = p.key;;) {
1587	>	V newValue = function.apply(key, oldValue);
1588	>	if (newValue == null)
1589	>	throw new NullPointerException();
1590	>	if (replaceNode(key, newValue, oldValue) != null ||
1591	>	(oldValue = get(key)) == null)
1592		break;
334	–	e = e.next;
1593		}
1594	+	}
1595	+	}
1596	+	}
1597
1598	<	V v = e.value;
1599	<	e.value = newValue;
1600	<	count = c; // write-volatile
1601	<	return v;
1602	<
1603	<	} finally {
1604	<	unlock();
1598	>	/**
1599	>	* Helper method for EntrySetView.removeIf.
1600	>	*/
1601	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1602	>	if (function == null) throw new NullPointerException();
1603	>	Node<K,V>[] t;
1604	>	boolean removed = false;
1605	>	if ((t = table) != null) {
1606	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1607	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1608	>	K k = p.key;
1609	>	V v = p.val;
1610	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1611	>	if (function.test(e) && replaceNode(k, null, v) != null)
1612	>	removed = true;
1613		}
1614		}
1615	+	return removed;
1616	+	}
1617
1618	+	/**
1619	+	* Helper method for ValuesView.removeIf.
1620	+	*/
1621	+	boolean removeValueIf(Predicate<? super V> function) {
1622	+	if (function == null) throw new NullPointerException();
1623	+	Node<K,V>[] t;
1624	+	boolean removed = false;
1625	+	if ((t = table) != null) {
1626	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1627	+	for (Node<K,V> p; (p = it.advance()) != null; ) {
1628	+	K k = p.key;
1629	+	V v = p.val;
1630	+	if (function.test(v) && replaceNode(k, null, v) != null)
1631	+	removed = true;
1632	+	}
1633	+	}
1634	+	return removed;
1635	+	}
1636
1637	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
1638	<	lock();
1639	<	try {
1640	<	int c = count;
1641	<	HashEntry[] tab = table;
1642	<	int index = hash & (tab.length - 1);
1643	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
1644	<
1645	<	for (HashEntry<K,V> e = first; e != null; e = (HashEntry<K,V>) e.next) {
1646	<	if (e.hash == hash && key.equals(e.key)) {
1647	<	V oldValue = e.value;
1648	<	if (!onlyIfAbsent)
1649	<	e.value = value;
1650	<	++modCount;
1651	<	count = c; // write-volatile
1652	<	return oldValue;
1637	>	/**
1638	>	* If the specified key is not already associated with a value,
1639	>	* attempts to compute its value using the given mapping function
1640	>	* and enters it into this map unless {@code null}.  The entire
1641	>	* method invocation is performed atomically, so the function is
1642	>	* applied at most once per key.  Some attempted update operations
1643	>	* on this map by other threads may be blocked while computation
1644	>	* is in progress, so the computation should be short and simple,
1645	>	* and must not attempt to update any other mappings of this map.
1646	>	*
1647	>	* @param key key with which the specified value is to be associated
1648	>	* @param mappingFunction the function to compute a value
1649	>	* @return the current (existing or computed) value associated with
1650	>	*         the specified key, or null if the computed value is null
1651	>	* @throws NullPointerException if the specified key or mappingFunction
1652	>	*         is null
1653	>	* @throws IllegalStateException if the computation detectably
1654	>	*         attempts a recursive update to this map that would
1655	>	*         otherwise never complete
1656	>	* @throws RuntimeException or Error if the mappingFunction does so,
1657	>	*         in which case the mapping is left unestablished
1658	>	*/
1659	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1660	>	if (key == null || mappingFunction == null)
1661	>	throw new NullPointerException();
1662	>	int h = spread(key.hashCode());
1663	>	V val = null;
1664	>	int binCount = 0;
1665	>	for (Node<K,V>[] tab = table;;) {
1666	>	Node<K,V> f; int n, i, fh; K fk; V fv;
1667	>	if (tab == null || (n = tab.length) == 0)
1668	>	tab = initTable();
1669	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1670	>	Node<K,V> r = new ReservationNode<K,V>();
1671	>	synchronized (r) {
1672	>	if (casTabAt(tab, i, null, r)) {
1673	>	binCount = 1;
1674	>	Node<K,V> node = null;
1675	>	try {
1676	>	if ((val = mappingFunction.apply(key)) != null)
1677	>	node = new Node<K,V>(h, key, val);
1678	>	} finally {
1679	>	setTabAt(tab, i, node);
1680	>	}
1681		}
1682		}
1683	<
1684	<	tab[index] = new HashEntry<K,V>(hash, key, value, first);
1685	<	++modCount;
1686	<	++c;
1687	<	count = c; // write-volatile
1688	<	if (c > threshold)
1689	<	setTable(rehash(tab));
1690	<	return null;
1691	<	} finally {
1692	<	unlock();
1683	>	if (binCount != 0)
1684	>	break;
1685	>	}
1686	>	else if ((fh = f.hash) == MOVED)
1687	>	tab = helpTransfer(tab, f);
1688	>	else if (fh == h    // check first node without acquiring lock
1689	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
1690	>	&& (fv = f.val) != null)
1691	>	return fv;
1692	>	else {
1693	>	boolean added = false;
1694	>	synchronized (f) {
1695	>	if (tabAt(tab, i) == f) {
1696	>	if (fh >= 0) {
1697	>	binCount = 1;
1698	>	for (Node<K,V> e = f;; ++binCount) {
1699	>	K ek;
1700	>	if (e.hash == h &&
1701	>	((ek = e.key) == key ||
1702	>	(ek != null && key.equals(ek)))) {
1703	>	val = e.val;
1704	>	break;
1705	>	}
1706	>	Node<K,V> pred = e;
1707	>	if ((e = e.next) == null) {
1708	>	if ((val = mappingFunction.apply(key)) != null) {
1709	>	if (pred.next != null)
1710	>	throw new IllegalStateException("Recursive update");
1711	>	added = true;
1712	>	pred.next = new Node<K,V>(h, key, val);
1713	>	}
1714	>	break;
1715	>	}
1716	>	}
1717	>	}
1718	>	else if (f instanceof TreeBin) {
1719	>	binCount = 2;
1720	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1721	>	TreeNode<K,V> r, p;
1722	>	if ((r = t.root) != null &&
1723	>	(p = r.findTreeNode(h, key, null)) != null)
1724	>	val = p.val;
1725	>	else if ((val = mappingFunction.apply(key)) != null) {
1726	>	added = true;
1727	>	t.putTreeVal(h, key, val);
1728	>	}
1729	>	}
1730	>	else if (f instanceof ReservationNode)
1731	>	throw new IllegalStateException("Recursive update");
1732	>	}
1733	>	}
1734	>	if (binCount != 0) {
1735	>	if (binCount >= TREEIFY_THRESHOLD)
1736	>	treeifyBin(tab, i);
1737	>	if (!added)
1738	>	return val;
1739	>	break;
1740	>	}
1741		}
1742		}
1743	+	if (val != null)
1744	+	addCount(1L, binCount);
1745	+	return val;
1746	+	}
1747
1748	<	private HashEntry[] rehash(HashEntry[] oldTable) {
1749	<	int oldCapacity = oldTable.length;
1750	<	if (oldCapacity >= MAXIMUM_CAPACITY)
1751	<	return oldTable;
1752	<
1753	<	/*
1754	<	* Reclassify nodes in each list to new Map.  Because we are
1755	<	* using power-of-two expansion, the elements from each bin
1756	<	* must either stay at same index, or move with a power of two
1757	<	* offset. We eliminate unnecessary node creation by catching
1758	<	* cases where old nodes can be reused because their next
1759	<	* fields won't change. Statistically, at the default
1760	<	* threshold, only about one-sixth of them need cloning when
1761	<	* a table doubles. The nodes they replace will be garbage
1762	<	* collectable as soon as they are no longer referenced by any
1763	<	* reader thread that may be in the midst of traversing table
1764	<	* right now.
1765	<	*/
1766	<
1767	<	HashEntry[] newTable = new HashEntry[oldCapacity << 1];
1768	<	int sizeMask = newTable.length - 1;
1769	<	for (int i = 0; i < oldCapacity ; i++) {
1770	<	// We need to guarantee that any existing reads of old Map can
1771	<	//  proceed. So we cannot yet null out each bin.
1772	<	HashEntry<K,V> e = (HashEntry<K,V>)oldTable[i];
1773	<
1774	<	if (e != null) {
1775	<	HashEntry<K,V> next = e.next;
1776	<	int idx = e.hash & sizeMask;
1777	<
1778	<	//  Single node on list
1779	<	if (next == null)
1780	<	newTable[idx] = e;
1748	>	/**
1749	>	* If the value for the specified key is present, attempts to
1750	>	* compute a new mapping given the key and its current mapped
1751	>	* value.  The entire method invocation is performed atomically.
1752	>	* Some attempted update operations on this map by other threads
1753	>	* may be blocked while computation is in progress, so the
1754	>	* computation should be short and simple, and must not attempt to
1755	>	* update any other mappings of this map.
1756	>	*
1757	>	* @param key key with which a value may be associated
1758	>	* @param remappingFunction the function to compute a value
1759	>	* @return the new value associated with the specified key, or null if none
1760	>	* @throws NullPointerException if the specified key or remappingFunction
1761	>	*         is null
1762	>	* @throws IllegalStateException if the computation detectably
1763	>	*         attempts a recursive update to this map that would
1764	>	*         otherwise never complete
1765	>	* @throws RuntimeException or Error if the remappingFunction does so,
1766	>	*         in which case the mapping is unchanged
1767	>	*/
1768	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1769	>	if (key == null || remappingFunction == null)
1770	>	throw new NullPointerException();
1771	>	int h = spread(key.hashCode());
1772	>	V val = null;
1773	>	int delta = 0;
1774	>	int binCount = 0;
1775	>	for (Node<K,V>[] tab = table;;) {
1776	>	Node<K,V> f; int n, i, fh;
1777	>	if (tab == null || (n = tab.length) == 0)
1778	>	tab = initTable();
1779	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1780	>	break;
1781	>	else if ((fh = f.hash) == MOVED)
1782	>	tab = helpTransfer(tab, f);
1783	>	else {
1784	>	synchronized (f) {
1785	>	if (tabAt(tab, i) == f) {
1786	>	if (fh >= 0) {
1787	>	binCount = 1;
1788	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1789	>	K ek;
1790	>	if (e.hash == h &&
1791	>	((ek = e.key) == key ||
1792	>	(ek != null && key.equals(ek)))) {
1793	>	val = remappingFunction.apply(key, e.val);
1794	>	if (val != null)
1795	>	e.val = val;
1796	>	else {
1797	>	delta = -1;
1798	>	Node<K,V> en = e.next;
1799	>	if (pred != null)
1800	>	pred.next = en;
1801	>	else
1802	>	setTabAt(tab, i, en);
1803	>	}
1804	>	break;
1805	>	}
1806	>	pred = e;
1807	>	if ((e = e.next) == null)
1808	>	break;
1809	>	}
1810	>	}
1811	>	else if (f instanceof TreeBin) {
1812	>	binCount = 2;
1813	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1814	>	TreeNode<K,V> r, p;
1815	>	if ((r = t.root) != null &&
1816	>	(p = r.findTreeNode(h, key, null)) != null) {
1817	>	val = remappingFunction.apply(key, p.val);
1818	>	if (val != null)
1819	>	p.val = val;
1820	>	else {
1821	>	delta = -1;
1822	>	if (t.removeTreeNode(p))
1823	>	setTabAt(tab, i, untreeify(t.first));
1824	>	}
1825	>	}
1826	>	}
1827	>	else if (f instanceof ReservationNode)
1828	>	throw new IllegalStateException("Recursive update");
1829	>	}
1830	>	}
1831	>	if (binCount != 0)
1832	>	break;
1833	>	}
1834	>	}
1835	>	if (delta != 0)
1836	>	addCount((long)delta, binCount);
1837	>	return val;
1838	>	}
1839
1840	<	else {
1841	<	// Reuse trailing consecutive sequence at same slot
1842	<	HashEntry<K,V> lastRun = e;
1843	<	int lastIdx = idx;
1844	<	for (HashEntry<K,V> last = next;
1845	<	last != null;
1846	<	last = last.next) {
1847	<	int k = last.hash & sizeMask;
1848	<	if (k != lastIdx) {
1849	<	lastIdx = k;
1850	<	lastRun = last;
1840	>	/**
1841	>	* Attempts to compute a mapping for the specified key and its
1842	>	* current mapped value (or {@code null} if there is no current
1843	>	* mapping). The entire method invocation is performed atomically.
1844	>	* Some attempted update operations on this map by other threads
1845	>	* may be blocked while computation is in progress, so the
1846	>	* computation should be short and simple, and must not attempt to
1847	>	* update any other mappings of this Map.
1848	>	*
1849	>	* @param key key with which the specified value is to be associated
1850	>	* @param remappingFunction the function to compute a value
1851	>	* @return the new value associated with the specified key, or null if none
1852	>	* @throws NullPointerException if the specified key or remappingFunction
1853	>	*         is null
1854	>	* @throws IllegalStateException if the computation detectably
1855	>	*         attempts a recursive update to this map that would
1856	>	*         otherwise never complete
1857	>	* @throws RuntimeException or Error if the remappingFunction does so,
1858	>	*         in which case the mapping is unchanged
1859	>	*/
1860	>	public V compute(K key,
1861	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1862	>	if (key == null || remappingFunction == null)
1863	>	throw new NullPointerException();
1864	>	int h = spread(key.hashCode());
1865	>	V val = null;
1866	>	int delta = 0;
1867	>	int binCount = 0;
1868	>	for (Node<K,V>[] tab = table;;) {
1869	>	Node<K,V> f; int n, i, fh;
1870	>	if (tab == null || (n = tab.length) == 0)
1871	>	tab = initTable();
1872	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1873	>	Node<K,V> r = new ReservationNode<K,V>();
1874	>	synchronized (r) {
1875	>	if (casTabAt(tab, i, null, r)) {
1876	>	binCount = 1;
1877	>	Node<K,V> node = null;
1878	>	try {
1879	>	if ((val = remappingFunction.apply(key, null)) != null) {
1880	>	delta = 1;
1881	>	node = new Node<K,V>(h, key, val);
1882		}
1883	+	} finally {
1884	+	setTabAt(tab, i, node);
1885		}
1886	<	newTable[lastIdx] = lastRun;
1886	>	}
1887	>	}
1888	>	if (binCount != 0)
1889	>	break;
1890	>	}
1891	>	else if ((fh = f.hash) == MOVED)
1892	>	tab = helpTransfer(tab, f);
1893	>	else {
1894	>	synchronized (f) {
1895	>	if (tabAt(tab, i) == f) {
1896	>	if (fh >= 0) {
1897	>	binCount = 1;
1898	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1899	>	K ek;
1900	>	if (e.hash == h &&
1901	>	((ek = e.key) == key ||
1902	>	(ek != null && key.equals(ek)))) {
1903	>	val = remappingFunction.apply(key, e.val);
1904	>	if (val != null)
1905	>	e.val = val;
1906	>	else {
1907	>	delta = -1;
1908	>	Node<K,V> en = e.next;
1909	>	if (pred != null)
1910	>	pred.next = en;
1911	>	else
1912	>	setTabAt(tab, i, en);
1913	>	}
1914	>	break;
1915	>	}
1916	>	pred = e;
1917	>	if ((e = e.next) == null) {
1918	>	val = remappingFunction.apply(key, null);
1919	>	if (val != null) {
1920	>	if (pred.next != null)
1921	>	throw new IllegalStateException("Recursive update");
1922	>	delta = 1;
1923	>	pred.next = new Node<K,V>(h, key, val);
1924	>	}
1925	>	break;
1926	>	}
1927	>	}
1928	>	}
1929	>	else if (f instanceof TreeBin) {
1930	>	binCount = 1;
1931	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1932	>	TreeNode<K,V> r, p;
1933	>	if ((r = t.root) != null)
1934	>	p = r.findTreeNode(h, key, null);
1935	>	else
1936	>	p = null;
1937	>	V pv = (p == null) ? null : p.val;
1938	>	val = remappingFunction.apply(key, pv);
1939	>	if (val != null) {
1940	>	if (p != null)
1941	>	p.val = val;
1942	>	else {
1943	>	delta = 1;
1944	>	t.putTreeVal(h, key, val);
1945	>	}
1946	>	}
1947	>	else if (p != null) {
1948	>	delta = -1;
1949	>	if (t.removeTreeNode(p))
1950	>	setTabAt(tab, i, untreeify(t.first));
1951	>	}
1952	>	}
1953	>	else if (f instanceof ReservationNode)
1954	>	throw new IllegalStateException("Recursive update");
1955	>	}
1956	>	}
1957	>	if (binCount != 0) {
1958	>	if (binCount >= TREEIFY_THRESHOLD)
1959	>	treeifyBin(tab, i);
1960	>	break;
1961	>	}
1962	>	}
1963	>	}
1964	>	if (delta != 0)
1965	>	addCount((long)delta, binCount);
1966	>	return val;
1967	>	}
1968
1969	<	// Clone all remaining nodes
1970	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1971	<	int k = p.hash & sizeMask;
1972	<	newTable[k] = new HashEntry<K,V>(p.hash,
1973	<	p.key,
1974	<	p.value,
1975	<	(HashEntry<K,V>) newTable[k]);
1969	>	/**
1970	>	* If the specified key is not already associated with a
1971	>	* (non-null) value, associates it with the given value.
1972	>	* Otherwise, replaces the value with the results of the given
1973	>	* remapping function, or removes if {@code null}. The entire
1974	>	* method invocation is performed atomically.  Some attempted
1975	>	* update operations on this map by other threads may be blocked
1976	>	* while computation is in progress, so the computation should be
1977	>	* short and simple, and must not attempt to update any other
1978	>	* mappings of this Map.
1979	>	*
1980	>	* @param key key with which the specified value is to be associated
1981	>	* @param value the value to use if absent
1982	>	* @param remappingFunction the function to recompute a value if present
1983	>	* @return the new value associated with the specified key, or null if none
1984	>	* @throws NullPointerException if the specified key or the
1985	>	*         remappingFunction is null
1986	>	* @throws RuntimeException or Error if the remappingFunction does so,
1987	>	*         in which case the mapping is unchanged
1988	>	*/
1989	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1990	>	if (key == null || value == null || remappingFunction == null)
1991	>	throw new NullPointerException();
1992	>	int h = spread(key.hashCode());
1993	>	V val = null;
1994	>	int delta = 0;
1995	>	int binCount = 0;
1996	>	for (Node<K,V>[] tab = table;;) {
1997	>	Node<K,V> f; int n, i, fh;
1998	>	if (tab == null || (n = tab.length) == 0)
1999	>	tab = initTable();
2000	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
2001	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value))) {
2002	>	delta = 1;
2003	>	val = value;
2004	>	break;
2005	>	}
2006	>	}
2007	>	else if ((fh = f.hash) == MOVED)
2008	>	tab = helpTransfer(tab, f);
2009	>	else {
2010	>	synchronized (f) {
2011	>	if (tabAt(tab, i) == f) {
2012	>	if (fh >= 0) {
2013	>	binCount = 1;
2014	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2015	>	K ek;
2016	>	if (e.hash == h &&
2017	>	((ek = e.key) == key ||
2018	>	(ek != null && key.equals(ek)))) {
2019	>	val = remappingFunction.apply(e.val, value);
2020	>	if (val != null)
2021	>	e.val = val;
2022	>	else {
2023	>	delta = -1;
2024	>	Node<K,V> en = e.next;
2025	>	if (pred != null)
2026	>	pred.next = en;
2027	>	else
2028	>	setTabAt(tab, i, en);
2029	>	}
2030	>	break;
2031	>	}
2032	>	pred = e;
2033	>	if ((e = e.next) == null) {
2034	>	delta = 1;
2035	>	val = value;
2036	>	pred.next = new Node<K,V>(h, key, val);
2037	>	break;
2038	>	}
2039	>	}
2040	>	}
2041	>	else if (f instanceof TreeBin) {
2042	>	binCount = 2;
2043	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2044	>	TreeNode<K,V> r = t.root;
2045	>	TreeNode<K,V> p = (r == null) ? null :
2046	>	r.findTreeNode(h, key, null);
2047	>	val = (p == null) ? value :
2048	>	remappingFunction.apply(p.val, value);
2049	>	if (val != null) {
2050	>	if (p != null)
2051	>	p.val = val;
2052	>	else {
2053	>	delta = 1;
2054	>	t.putTreeVal(h, key, val);
2055	>	}
2056	>	}
2057	>	else if (p != null) {
2058	>	delta = -1;
2059	>	if (t.removeTreeNode(p))
2060	>	setTabAt(tab, i, untreeify(t.first));
2061	>	}
2062		}
2063	+	else if (f instanceof ReservationNode)
2064	+	throw new IllegalStateException("Recursive update");
2065		}
2066		}
2067	+	if (binCount != 0) {
2068	+	if (binCount >= TREEIFY_THRESHOLD)
2069	+	treeifyBin(tab, i);
2070	+	break;
2071	+	}
2072		}
439	–	return newTable;
2073		}
2074	+	if (delta != 0)
2075	+	addCount((long)delta, binCount);
2076	+	return val;
2077	+	}
2078
2079	<	/**
2080	<	* Remove; match on key only if value null, else match both.
2081	<	*/
2082	<	V remove(Object key, int hash, Object value) {
2083	<	lock();
2084	<	try {
2085	<	int c = count;
2086	<	HashEntry[] tab = table;
2087	<	int index = hash & (tab.length - 1);
2088	<	HashEntry<K,V> first = (HashEntry<K,V>)tab[index];
2079	>	// Hashtable legacy methods
2080	>
2081	>	/**
2082	>	* Tests if some key maps into the specified value in this table.
2083	>	*
2084	>	* <p>Note that this method is identical in functionality to
2085	>	* {@link #containsValue(Object)}, and exists solely to ensure
2086	>	* full compatibility with class {@link java.util.Hashtable},
2087	>	* which supported this method prior to introduction of the
2088	>	* Java Collections Framework.
2089	>	*
2090	>	* @param  value a value to search for
2091	>	* @return {@code true} if and only if some key maps to the
2092	>	*         {@code value} argument in this table as
2093	>	*         determined by the {@code equals} method;
2094	>	*         {@code false} otherwise
2095	>	* @throws NullPointerException if the specified value is null
2096	>	*/
2097	>	public boolean contains(Object value) {
2098	>	return containsValue(value);
2099	>	}
2100	>
2101	>	/**
2102	>	* Returns an enumeration of the keys in this table.
2103	>	*
2104	>	* @return an enumeration of the keys in this table
2105	>	* @see #keySet()
2106	>	*/
2107	>	public Enumeration<K> keys() {
2108	>	Node<K,V>[] t;
2109	>	int f = (t = table) == null ? 0 : t.length;
2110	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2111	>	}
2112	>
2113	>	/**
2114	>	* Returns an enumeration of the values in this table.
2115	>	*
2116	>	* @return an enumeration of the values in this table
2117	>	* @see #values()
2118	>	*/
2119	>	public Enumeration<V> elements() {
2120	>	Node<K,V>[] t;
2121	>	int f = (t = table) == null ? 0 : t.length;
2122	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2123	>	}
2124	>
2125	>	// ConcurrentHashMap-only methods
2126	>
2127	>	/**
2128	>	* Returns the number of mappings. This method should be used
2129	>	* instead of {@link #size} because a ConcurrentHashMap may
2130	>	* contain more mappings than can be represented as an int. The
2131	>	* value returned is an estimate; the actual count may differ if
2132	>	* there are concurrent insertions or removals.
2133	>	*
2134	>	* @return the number of mappings
2135	>	* @since 1.8
2136	>	*/
2137	>	public long mappingCount() {
2138	>	long n = sumCount();
2139	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2140	>	}
2141	>
2142	>	/**
2143	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2144	>	* from the given type to {@code Boolean.TRUE}.
2145	>	*
2146	>	* @param <K> the element type of the returned set
2147	>	* @return the new set
2148	>	* @since 1.8
2149	>	*/
2150	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2151	>	return new KeySetView<K,Boolean>
2152	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2153	>	}
2154	>
2155	>	/**
2156	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2157	>	* from the given type to {@code Boolean.TRUE}.
2158	>	*
2159	>	* @param initialCapacity The implementation performs internal
2160	>	* sizing to accommodate this many elements.
2161	>	* @param <K> the element type of the returned set
2162	>	* @return the new set
2163	>	* @throws IllegalArgumentException if the initial capacity of
2164	>	* elements is negative
2165	>	* @since 1.8
2166	>	*/
2167	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2168	>	return new KeySetView<K,Boolean>
2169	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2170	>	}
2171	>
2172	>	/**
2173	>	* Returns a {@link Set} view of the keys in this map, using the
2174	>	* given common mapped value for any additions (i.e., {@link
2175	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2176	>	* This is of course only appropriate if it is acceptable to use
2177	>	* the same value for all additions from this view.
2178	>	*
2179	>	* @param mappedValue the mapped value to use for any additions
2180	>	* @return the set view
2181	>	* @throws NullPointerException if the mappedValue is null
2182	>	*/
2183	>	public KeySetView<K,V> keySet(V mappedValue) {
2184	>	if (mappedValue == null)
2185	>	throw new NullPointerException();
2186	>	return new KeySetView<K,V>(this, mappedValue);
2187	>	}
2188	>
2189	>	/* ---------------- Special Nodes -------------- */
2190
2191	<	HashEntry<K,V> e = first;
2191	>	/**
2192	>	* A node inserted at head of bins during transfer operations.
2193	>	*/
2194	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2195	>	final Node<K,V>[] nextTable;
2196	>	ForwardingNode(Node<K,V>[] tab) {
2197	>	super(MOVED, null, null);
2198	>	this.nextTable = tab;
2199	>	}
2200	>
2201	>	Node<K,V> find(int h, Object k) {
2202	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2203	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2204	>	Node<K,V> e; int n;
2205	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2206	>	(e = tabAt(tab, (n - 1) & h)) == null)
2207	>	return null;
2208		for (;;) {
2209	<	if (e == null)
2209	>	int eh; K ek;
2210	>	if ((eh = e.hash) == h &&
2211	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2212	>	return e;
2213	>	if (eh < 0) {
2214	>	if (e instanceof ForwardingNode) {
2215	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2216	>	continue outer;
2217	>	}
2218	>	else
2219	>	return e.find(h, k);
2220	>	}
2221	>	if ((e = e.next) == null)
2222		return null;
457	–	if (e.hash == hash && key.equals(e.key))
458	–	break;
459	–	e = e.next;
2223		}
2224	+	}
2225	+	}
2226	+	}
2227
2228	<	V oldValue = e.value;
2229	<	if (value != null && !value.equals(oldValue))
2230	<	return null;
2228	>	/**
2229	>	* A place-holder node used in computeIfAbsent and compute.
2230	>	*/
2231	>	static final class ReservationNode<K,V> extends Node<K,V> {
2232	>	ReservationNode() {
2233	>	super(RESERVED, null, null);
2234	>	}
2235
2236	<	// All entries following removed node can stay in list, but
2237	<	// all preceding ones need to be cloned.
2238	<	HashEntry<K,V> newFirst = e.next;
2239	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
2240	<	newFirst = new HashEntry<K,V>(p.hash, p.key,
2241	<	p.value, newFirst);
2242	<	tab[index] = newFirst;
2243	<	++modCount;
2244	<	count = c-1; // write-volatile
2245	<	return oldValue;
2246	<	} finally {
2247	<	unlock();
2236	>	Node<K,V> find(int h, Object k) {
2237	>	return null;
2238	>	}
2239	>	}
2240	>
2241	>	/* ---------------- Table Initialization and Resizing -------------- */
2242	>
2243	>	/**
2244	>	* Returns the stamp bits for resizing a table of size n.
2245	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2246	>	*/
2247	>	static final int resizeStamp(int n) {
2248	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2249	>	}
2250	>
2251	>	/**
2252	>	* Initializes table, using the size recorded in sizeCtl.
2253	>	*/
2254	>	private final Node<K,V>[] initTable() {
2255	>	Node<K,V>[] tab; int sc;
2256	>	while ((tab = table) == null || tab.length == 0) {
2257	>	if ((sc = sizeCtl) < 0)
2258	>	Thread.yield(); // lost initialization race; just spin
2259	>	else if (U.compareAndSetInt(this, SIZECTL, sc, -1)) {
2260	>	try {
2261	>	if ((tab = table) == null || tab.length == 0) {
2262	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2263	>	@SuppressWarnings("unchecked")
2264	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2265	>	table = tab = nt;
2266	>	sc = n - (n >>> 2);
2267	>	}
2268	>	} finally {
2269	>	sizeCtl = sc;
2270	>	}
2271	>	break;
2272		}
2273		}
2274	+	return tab;
2275	+	}
2276
2277	<	void clear() {
2278	<	lock();
2279	<	try {
2280	<	HashEntry[] tab = table;
2281	<	for (int i = 0; i < tab.length ; i++)
2282	<	tab[i] = null;
2283	<	++modCount;
2284	<	count = 0; // write-volatile
2285	<	} finally {
2286	<	unlock();
2277	>	/**
2278	>	* Adds to count, and if table is too small and not already
2279	>	* resizing, initiates transfer. If already resizing, helps
2280	>	* perform transfer if work is available.  Rechecks occupancy
2281	>	* after a transfer to see if another resize is already needed
2282	>	* because resizings are lagging additions.
2283	>	*
2284	>	* @param x the count to add
2285	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2286	>	*/
2287	>	private final void addCount(long x, int check) {
2288	>	CounterCell[] cs; long b, s;
2289	>	if ((cs = counterCells) != null ||
2290	>	!U.compareAndSetLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2291	>	CounterCell c; long v; int m;
2292	>	boolean uncontended = true;
2293	>	if (cs == null || (m = cs.length - 1) < 0 ||
2294	>	(c = cs[ThreadLocalRandom.getProbe() & m]) == null ||
2295	>	!(uncontended =
2296	>	U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x))) {
2297	>	fullAddCount(x, uncontended);
2298	>	return;
2299	>	}
2300	>	if (check <= 1)
2301	>	return;
2302	>	s = sumCount();
2303	>	}
2304	>	if (check >= 0) {
2305	>	Node<K,V>[] tab, nt; int n, sc;
2306	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2307	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2308	>	int rs = resizeStamp(n) << RESIZE_STAMP_SHIFT;
2309	>	if (sc < 0) {
2310	>	if (sc == rs + MAX_RESIZERS || sc == rs + 1 ||
2311	>	(nt = nextTable) == null || transferIndex <= 0)
2312	>	break;
2313	>	if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1))
2314	>	transfer(tab, nt);
2315	>	}
2316	>	else if (U.compareAndSetInt(this, SIZECTL, sc, rs + 2))
2317	>	transfer(tab, null);
2318	>	s = sumCount();
2319		}
2320		}
2321		}
2322
2323		/**
2324	<	* ConcurrentHashMap list entry. Note that this is never exported
497	<	* out as a user-visible Map.Entry
2324	>	* Helps transfer if a resize is in progress.
2325		*/
2326	<	private static class HashEntry<K,V> {
2327	<	private final K key;
2328	<	private V value;
2329	<	private final int hash;
2330	<	private final HashEntry<K,V> next;
2326	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2327	>	Node<K,V>[] nextTab; int sc;
2328	>	if (tab != null && (f instanceof ForwardingNode) &&
2329	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2330	>	int rs = resizeStamp(tab.length) << RESIZE_STAMP_SHIFT;
2331	>	while (nextTab == nextTable && table == tab &&
2332	>	(sc = sizeCtl) < 0) {
2333	>	if (sc == rs + MAX_RESIZERS || sc == rs + 1 ||
2334	>	transferIndex <= 0)
2335	>	break;
2336	>	if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1)) {
2337	>	transfer(tab, nextTab);
2338	>	break;
2339	>	}
2340	>	}
2341	>	return nextTab;
2342	>	}
2343	>	return table;
2344	>	}
2345
2346	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
2347	<	this.value = value;
2348	<	this.hash = hash;
2349	<	this.key = key;
2350	<	this.next = next;
2346	>	/**
2347	>	* Tries to presize table to accommodate the given number of elements.
2348	>	*
2349	>	* @param size number of elements (doesn't need to be perfectly accurate)
2350	>	*/
2351	>	private final void tryPresize(int size) {
2352	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2353	>	tableSizeFor(size + (size >>> 1) + 1);
2354	>	int sc;
2355	>	while ((sc = sizeCtl) >= 0) {
2356	>	Node<K,V>[] tab = table; int n;
2357	>	if (tab == null || (n = tab.length) == 0) {
2358	>	n = (sc > c) ? sc : c;
2359	>	if (U.compareAndSetInt(this, SIZECTL, sc, -1)) {
2360	>	try {
2361	>	if (table == tab) {
2362	>	@SuppressWarnings("unchecked")
2363	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2364	>	table = nt;
2365	>	sc = n - (n >>> 2);
2366	>	}
2367	>	} finally {
2368	>	sizeCtl = sc;
2369	>	}
2370	>	}
2371	>	}
2372	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2373	>	break;
2374	>	else if (tab == table) {
2375	>	int rs = resizeStamp(n);
2376	>	if (U.compareAndSetInt(this, SIZECTL, sc,
2377	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2378	>	transfer(tab, null);
2379	>	}
2380		}
2381		}
2382
2383	+	/**
2384	+	* Moves and/or copies the nodes in each bin to new table. See
2385	+	* above for explanation.
2386	+	*/
2387	+	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2388	+	int n = tab.length, stride;
2389	+	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2390	+	stride = MIN_TRANSFER_STRIDE; // subdivide range
2391	+	if (nextTab == null) {            // initiating
2392	+	try {
2393	+	@SuppressWarnings("unchecked")
2394	+	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2395	+	nextTab = nt;
2396	+	} catch (Throwable ex) {      // try to cope with OOME
2397	+	sizeCtl = Integer.MAX_VALUE;
2398	+	return;
2399	+	}
2400	+	nextTable = nextTab;
2401	+	transferIndex = n;
2402	+	}
2403	+	int nextn = nextTab.length;
2404	+	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2405	+	boolean advance = true;
2406	+	boolean finishing = false; // to ensure sweep before committing nextTab
2407	+	for (int i = 0, bound = 0;;) {
2408	+	Node<K,V> f; int fh;
2409	+	while (advance) {
2410	+	int nextIndex, nextBound;
2411	+	if (--i >= bound || finishing)
2412	+	advance = false;
2413	+	else if ((nextIndex = transferIndex) <= 0) {
2414	+	i = -1;
2415	+	advance = false;
2416	+	}
2417	+	else if (U.compareAndSetInt
2418	+	(this, TRANSFERINDEX, nextIndex,
2419	+	nextBound = (nextIndex > stride ?
2420	+	nextIndex - stride : 0))) {
2421	+	bound = nextBound;
2422	+	i = nextIndex - 1;
2423	+	advance = false;
2424	+	}
2425	+	}
2426	+	if (i < 0 || i >= n || i + n >= nextn) {
2427	+	int sc;
2428	+	if (finishing) {
2429	+	nextTable = null;
2430	+	table = nextTab;
2431	+	sizeCtl = (n << 1) - (n >>> 1);
2432	+	return;
2433	+	}
2434	+	if (U.compareAndSetInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2435	+	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2436	+	return;
2437	+	finishing = advance = true;
2438	+	i = n; // recheck before commit
2439	+	}
2440	+	}
2441	+	else if ((f = tabAt(tab, i)) == null)
2442	+	advance = casTabAt(tab, i, null, fwd);
2443	+	else if ((fh = f.hash) == MOVED)
2444	+	advance = true; // already processed
2445	+	else {
2446	+	synchronized (f) {
2447	+	if (tabAt(tab, i) == f) {
2448	+	Node<K,V> ln, hn;
2449	+	if (fh >= 0) {
2450	+	int runBit = fh & n;
2451	+	Node<K,V> lastRun = f;
2452	+	for (Node<K,V> p = f.next; p != null; p = p.next) {
2453	+	int b = p.hash & n;
2454	+	if (b != runBit) {
2455	+	runBit = b;
2456	+	lastRun = p;
2457	+	}
2458	+	}
2459	+	if (runBit == 0) {
2460	+	ln = lastRun;
2461	+	hn = null;
2462	+	}
2463	+	else {
2464	+	hn = lastRun;
2465	+	ln = null;
2466	+	}
2467	+	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2468	+	int ph = p.hash; K pk = p.key; V pv = p.val;
2469	+	if ((ph & n) == 0)
2470	+	ln = new Node<K,V>(ph, pk, pv, ln);
2471	+	else
2472	+	hn = new Node<K,V>(ph, pk, pv, hn);
2473	+	}
2474	+	setTabAt(nextTab, i, ln);
2475	+	setTabAt(nextTab, i + n, hn);
2476	+	setTabAt(tab, i, fwd);
2477	+	advance = true;
2478	+	}
2479	+	else if (f instanceof TreeBin) {
2480	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
2481	+	TreeNode<K,V> lo = null, loTail = null;
2482	+	TreeNode<K,V> hi = null, hiTail = null;
2483	+	int lc = 0, hc = 0;
2484	+	for (Node<K,V> e = t.first; e != null; e = e.next) {
2485	+	int h = e.hash;
2486	+	TreeNode<K,V> p = new TreeNode<K,V>
2487	+	(h, e.key, e.val, null, null);
2488	+	if ((h & n) == 0) {
2489	+	if ((p.prev = loTail) == null)
2490	+	lo = p;
2491	+	else
2492	+	loTail.next = p;
2493	+	loTail = p;
2494	+	++lc;
2495	+	}
2496	+	else {
2497	+	if ((p.prev = hiTail) == null)
2498	+	hi = p;
2499	+	else
2500	+	hiTail.next = p;
2501	+	hiTail = p;
2502	+	++hc;
2503	+	}
2504	+	}
2505	+	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2506	+	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2507	+	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2508	+	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2509	+	setTabAt(nextTab, i, ln);
2510	+	setTabAt(nextTab, i + n, hn);
2511	+	setTabAt(tab, i, fwd);
2512	+	advance = true;
2513	+	}
2514	+	else if (f instanceof ReservationNode)
2515	+	throw new IllegalStateException("Recursive update");
2516	+	}
2517	+	}
2518	+	}
2519	+	}
2520	+	}
2521
2522	<	/* ---------------- Public operations -------------- */
2522	>	/* ---------------- Counter support -------------- */
2523
2524		/**
2525	<	* Constructs a new, empty map with the specified initial
2526	<	* capacity and the specified load factor.
519	<	*
520	<	* @param initialCapacity the initial capacity. The implementation
521	<	* performs internal sizing to accommodate this many elements.
522	<	* @param loadFactor  the load factor threshold, used to control resizing.
523	<	* @param concurrencyLevel the estimated number of concurrently
524	<	* updating threads. The implementation performs internal sizing
525	<	* to try to accommodate this many threads.
526	<	* @throws IllegalArgumentException if the initial capacity is
527	<	* negative or the load factor or concurrencyLevel are
528	<	* nonpositive.
2525	>	* A padded cell for distributing counts.  Adapted from LongAdder
2526	>	* and Striped64.  See their internal docs for explanation.
2527		*/
2528	<	public ConcurrentHashMap(int initialCapacity,
2529	<	float loadFactor, int concurrencyLevel) {
2530	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
2531	<	throw new IllegalArgumentException();
534	<
535	<	if (concurrencyLevel > MAX_SEGMENTS)
536	<	concurrencyLevel = MAX_SEGMENTS;
2528	>	@jdk.internal.vm.annotation.Contended static final class CounterCell {
2529	>	volatile long value;
2530	>	CounterCell(long x) { value = x; }
2531	>	}
2532
2533	<	// Find power-of-two sizes best matching arguments
2534	<	int sshift = 0;
2535	<	int ssize = 1;
2536	<	while (ssize < concurrencyLevel) {
2537	<	++sshift;
2538	<	ssize <<= 1;
2533	>	final long sumCount() {
2534	>	CounterCell[] cs = counterCells;
2535	>	long sum = baseCount;
2536	>	if (cs != null) {
2537	>	for (CounterCell c : cs)
2538	>	if (c != null)
2539	>	sum += c.value;
2540		}
2541	<	segmentShift = 32 - sshift;
2542	<	segmentMask = ssize - 1;
547	<	this.segments = new Segment[ssize];
548	<
549	<	if (initialCapacity > MAXIMUM_CAPACITY)
550	<	initialCapacity = MAXIMUM_CAPACITY;
551	<	int c = initialCapacity / ssize;
552	<	if (c * ssize < initialCapacity)
553	<	++c;
554	<	int cap = 1;
555	<	while (cap < c)
556	<	cap <<= 1;
2541	>	return sum;
2542	>	}
2543
2544	<	for (int i = 0; i < this.segments.length; ++i)
2545	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
2544	>	// See LongAdder version for explanation
2545	>	private final void fullAddCount(long x, boolean wasUncontended) {
2546	>	int h;
2547	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2548	>	ThreadLocalRandom.localInit();      // force initialization
2549	>	h = ThreadLocalRandom.getProbe();
2550	>	wasUncontended = true;
2551	>	}
2552	>	boolean collide = false;                // True if last slot nonempty
2553	>	for (;;) {
2554	>	CounterCell[] cs; CounterCell c; int n; long v;
2555	>	if ((cs = counterCells) != null && (n = cs.length) > 0) {
2556	>	if ((c = cs[(n - 1) & h]) == null) {
2557	>	if (cellsBusy == 0) {            // Try to attach new Cell
2558	>	CounterCell r = new CounterCell(x); // Optimistic create
2559	>	if (cellsBusy == 0 &&
2560	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2561	>	boolean created = false;
2562	>	try {               // Recheck under lock
2563	>	CounterCell[] rs; int m, j;
2564	>	if ((rs = counterCells) != null &&
2565	>	(m = rs.length) > 0 &&
2566	>	rs[j = (m - 1) & h] == null) {
2567	>	rs[j] = r;
2568	>	created = true;
2569	>	}
2570	>	} finally {
2571	>	cellsBusy = 0;
2572	>	}
2573	>	if (created)
2574	>	break;
2575	>	continue;           // Slot is now non-empty
2576	>	}
2577	>	}
2578	>	collide = false;
2579	>	}
2580	>	else if (!wasUncontended)       // CAS already known to fail
2581	>	wasUncontended = true;      // Continue after rehash
2582	>	else if (U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x))
2583	>	break;
2584	>	else if (counterCells != cs || n >= NCPU)
2585	>	collide = false;            // At max size or stale
2586	>	else if (!collide)
2587	>	collide = true;
2588	>	else if (cellsBusy == 0 &&
2589	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2590	>	try {
2591	>	if (counterCells == cs) // Expand table unless stale
2592	>	counterCells = Arrays.copyOf(cs, n << 1);
2593	>	} finally {
2594	>	cellsBusy = 0;
2595	>	}
2596	>	collide = false;
2597	>	continue;                   // Retry with expanded table
2598	>	}
2599	>	h = ThreadLocalRandom.advanceProbe(h);
2600	>	}
2601	>	else if (cellsBusy == 0 && counterCells == cs &&
2602	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2603	>	boolean init = false;
2604	>	try {                           // Initialize table
2605	>	if (counterCells == cs) {
2606	>	CounterCell[] rs = new CounterCell[2];
2607	>	rs[h & 1] = new CounterCell(x);
2608	>	counterCells = rs;
2609	>	init = true;
2610	>	}
2611	>	} finally {
2612	>	cellsBusy = 0;
2613	>	}
2614	>	if (init)
2615	>	break;
2616	>	}
2617	>	else if (U.compareAndSetLong(this, BASECOUNT, v = baseCount, v + x))
2618	>	break;                          // Fall back on using base
2619	>	}
2620		}
2621
2622	+	/* ---------------- Conversion from/to TreeBins -------------- */
2623	+
2624		/**
2625	<	* Constructs a new, empty map with the specified initial
2626	<	* capacity,  and with default load factor and concurrencyLevel.
565	<	*
566	<	* @param initialCapacity The implementation performs internal
567	<	* sizing to accommodate this many elements.
568	<	* @throws IllegalArgumentException if the initial capacity of
569	<	* elements is negative.
2625	>	* Replaces all linked nodes in bin at given index unless table is
2626	>	* too small, in which case resizes instead.
2627		*/
2628	<	public ConcurrentHashMap(int initialCapacity) {
2629	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2628	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2629	>	Node<K,V> b; int n;
2630	>	if (tab != null) {
2631	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2632	>	tryPresize(n << 1);
2633	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2634	>	synchronized (b) {
2635	>	if (tabAt(tab, index) == b) {
2636	>	TreeNode<K,V> hd = null, tl = null;
2637	>	for (Node<K,V> e = b; e != null; e = e.next) {
2638	>	TreeNode<K,V> p =
2639	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2640	>	null, null);
2641	>	if ((p.prev = tl) == null)
2642	>	hd = p;
2643	>	else
2644	>	tl.next = p;
2645	>	tl = p;
2646	>	}
2647	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2648	>	}
2649	>	}
2650	>	}
2651	>	}
2652		}
2653
2654		/**
2655	<	* Constructs a new, empty map with a default initial capacity,
577	<	* load factor, and concurrencyLevel.
2655	>	* Returns a list of non-TreeNodes replacing those in given list.
2656		*/
2657	<	public ConcurrentHashMap() {
2658	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2657	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2658	>	Node<K,V> hd = null, tl = null;
2659	>	for (Node<K,V> q = b; q != null; q = q.next) {
2660	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val);
2661	>	if (tl == null)
2662	>	hd = p;
2663	>	else
2664	>	tl.next = p;
2665	>	tl = p;
2666	>	}
2667	>	return hd;
2668		}
2669
2670	+	/* ---------------- TreeNodes -------------- */
2671	+
2672		/**
2673	<	* Constructs a new map with the same mappings as the given map.  The
585	<	* map is created with a capacity of twice the number of mappings in
586	<	* the given map or 11 (whichever is greater), and a default load factor.
2673	>	* Nodes for use in TreeBins.
2674		*/
2675	<	public <A extends K, B extends V> ConcurrentHashMap(Map<A,B> t) {
2676	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
2677	<	11),
2678	<	DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
2679	<	putAll(t);
2680	<	}
2675	>	static final class TreeNode<K,V> extends Node<K,V> {
2676	>	TreeNode<K,V> parent;  // red-black tree links
2677	>	TreeNode<K,V> left;
2678	>	TreeNode<K,V> right;
2679	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2680	>	boolean red;
2681	>
2682	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2683	>	TreeNode<K,V> parent) {
2684	>	super(hash, key, val, next);
2685	>	this.parent = parent;
2686	>	}
2687
2688	<	// inherit Map javadoc
2689	<	public boolean isEmpty() {
597	<	final Segment[] segments = this.segments;
598	<	/*
599	<	* We need to keep track of per-segment modCounts to avoid ABA
600	<	* problems in which an element in one segment was added and
601	<	* in another removed during traversal, in which case the
602	<	* table was never actually empty at any point. Note the
603	<	* similar use of modCounts in the size() and containsValue()
604	<	* methods, which are the only other methods also susceptible
605	<	* to ABA problems.
606	<	*/
607	<	int[] mc = new int[segments.length];
608	<	int mcsum = 0;
609	<	for (int i = 0; i < segments.length; ++i) {
610	<	if (segments[i].count != 0)
611	<	return false;
612	<	else
613	<	mcsum += mc[i] = segments[i].modCount;
2688	>	Node<K,V> find(int h, Object k) {
2689	>	return findTreeNode(h, k, null);
2690		}
2691	<	// If mcsum happens to be zero, then we know we got a snapshot
2692	<	// before any modifications at all were made.  This is
2693	<	// probably common enough to bother tracking.
2694	<	if (mcsum != 0) {
2695	<	for (int i = 0; i < segments.length; ++i) {
2696	<	if (segments[i].count != 0 ||
2697	<	mc[i] != segments[i].modCount)
2698	<	return false;
2691	>
2692	>	/**
2693	>	* Returns the TreeNode (or null if not found) for the given key
2694	>	* starting at given root.
2695	>	*/
2696	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2697	>	if (k != null) {
2698	>	TreeNode<K,V> p = this;
2699	>	do {
2700	>	int ph, dir; K pk; TreeNode<K,V> q;
2701	>	TreeNode<K,V> pl = p.left, pr = p.right;
2702	>	if ((ph = p.hash) > h)
2703	>	p = pl;
2704	>	else if (ph < h)
2705	>	p = pr;
2706	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2707	>	return p;
2708	>	else if (pl == null)
2709	>	p = pr;
2710	>	else if (pr == null)
2711	>	p = pl;
2712	>	else if ((kc != null ||
2713	>	(kc = comparableClassFor(k)) != null) &&
2714	>	(dir = compareComparables(kc, k, pk)) != 0)
2715	>	p = (dir < 0) ? pl : pr;
2716	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2717	>	return q;
2718	>	else
2719	>	p = pl;
2720	>	} while (p != null);
2721		}
2722	+	return null;
2723		}
625	–	return true;
2724		}
2725
2726	<	// inherit Map javadoc
2727	<	public int size() {
2728	<	final Segment[] segments = this.segments;
2729	<	int[] mc = new int[segments.length];
2730	<	for (;;) {
2731	<	long sum = 0;
2732	<	int mcsum = 0;
2733	<	for (int i = 0; i < segments.length; ++i) {
2734	<	sum += segments[i].count;
2735	<	mcsum += mc[i] = segments[i].modCount;
2736	<	}
2737	<	int check = 0;
2738	<	if (mcsum != 0) {
2739	<	for (int i = 0; i < segments.length; ++i) {
2740	<	check += segments[i].count;
2741	<	if (mc[i] != segments[i].modCount) {
2742	<	check = -1; // force retry
2743	<	break;
2726	>	/* ---------------- TreeBins -------------- */
2727	>
2728	>	/**
2729	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2730	>	* keys or values, but instead point to list of TreeNodes and
2731	>	* their root. They also maintain a parasitic read-write lock
2732	>	* forcing writers (who hold bin lock) to wait for readers (who do
2733	>	* not) to complete before tree restructuring operations.
2734	>	*/
2735	>	static final class TreeBin<K,V> extends Node<K,V> {
2736	>	TreeNode<K,V> root;
2737	>	volatile TreeNode<K,V> first;
2738	>	volatile Thread waiter;
2739	>	volatile int lockState;
2740	>	// values for lockState
2741	>	static final int WRITER = 1; // set while holding write lock
2742	>	static final int WAITER = 2; // set when waiting for write lock
2743	>	static final int READER = 4; // increment value for setting read lock
2744	>
2745	>	/**
2746	>	* Tie-breaking utility for ordering insertions when equal
2747	>	* hashCodes and non-comparable. We don't require a total
2748	>	* order, just a consistent insertion rule to maintain
2749	>	* equivalence across rebalancings. Tie-breaking further than
2750	>	* necessary simplifies testing a bit.
2751	>	*/
2752	>	static int tieBreakOrder(Object a, Object b) {
2753	>	int d;
2754	>	if (a == null || b == null ||
2755	>	(d = a.getClass().getName().
2756	>	compareTo(b.getClass().getName())) == 0)
2757	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2758	>	-1 : 1);
2759	>	return d;
2760	>	}
2761	>
2762	>	/**
2763	>	* Creates bin with initial set of nodes headed by b.
2764	>	*/
2765	>	TreeBin(TreeNode<K,V> b) {
2766	>	super(TREEBIN, null, null);
2767	>	this.first = b;
2768	>	TreeNode<K,V> r = null;
2769	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2770	>	next = (TreeNode<K,V>)x.next;
2771	>	x.left = x.right = null;
2772	>	if (r == null) {
2773	>	x.parent = null;
2774	>	x.red = false;
2775	>	r = x;
2776	>	}
2777	>	else {
2778	>	K k = x.key;
2779	>	int h = x.hash;
2780	>	Class<?> kc = null;
2781	>	for (TreeNode<K,V> p = r;;) {
2782	>	int dir, ph;
2783	>	K pk = p.key;
2784	>	if ((ph = p.hash) > h)
2785	>	dir = -1;
2786	>	else if (ph < h)
2787	>	dir = 1;
2788	>	else if ((kc == null &&
2789	>	(kc = comparableClassFor(k)) == null) ||
2790	>	(dir = compareComparables(kc, k, pk)) == 0)
2791	>	dir = tieBreakOrder(k, pk);
2792	>	TreeNode<K,V> xp = p;
2793	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2794	>	x.parent = xp;
2795	>	if (dir <= 0)
2796	>	xp.left = x;
2797	>	else
2798	>	xp.right = x;
2799	>	r = balanceInsertion(r, x);
2800	>	break;
2801	>	}
2802		}
2803		}
2804		}
2805	<	if (check == sum) {
2806	<	if (sum > Integer.MAX_VALUE)
2807	<	return Integer.MAX_VALUE;
2805	>	this.root = r;
2806	>	assert checkInvariants(root);
2807	>	}
2808	>
2809	>	/**
2810	>	* Acquires write lock for tree restructuring.
2811	>	*/
2812	>	private final void lockRoot() {
2813	>	if (!U.compareAndSetInt(this, LOCKSTATE, 0, WRITER))
2814	>	contendedLock(); // offload to separate method
2815	>	}
2816	>
2817	>	/**
2818	>	* Releases write lock for tree restructuring.
2819	>	*/
2820	>	private final void unlockRoot() {
2821	>	lockState = 0;
2822	>	}
2823	>
2824	>	/**
2825	>	* Possibly blocks awaiting root lock.
2826	>	*/
2827	>	private final void contendedLock() {
2828	>	boolean waiting = false;
2829	>	for (int s;;) {
2830	>	if (((s = lockState) & ~WAITER) == 0) {
2831	>	if (U.compareAndSetInt(this, LOCKSTATE, s, WRITER)) {
2832	>	if (waiting)
2833	>	waiter = null;
2834	>	return;
2835	>	}
2836	>	}
2837	>	else if ((s & WAITER) == 0) {
2838	>	if (U.compareAndSetInt(this, LOCKSTATE, s, s | WAITER)) {
2839	>	waiting = true;
2840	>	waiter = Thread.currentThread();
2841	>	}
2842	>	}
2843	>	else if (waiting)
2844	>	LockSupport.park(this);
2845	>	}
2846	>	}
2847	>
2848	>	/**
2849	>	* Returns matching node or null if none. Tries to search
2850	>	* using tree comparisons from root, but continues linear
2851	>	* search when lock not available.
2852	>	*/
2853	>	final Node<K,V> find(int h, Object k) {
2854	>	if (k != null) {
2855	>	for (Node<K,V> e = first; e != null; ) {
2856	>	int s; K ek;
2857	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2858	>	if (e.hash == h &&
2859	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2860	>	return e;
2861	>	e = e.next;
2862	>	}
2863	>	else if (U.compareAndSetInt(this, LOCKSTATE, s,
2864	>	s + READER)) {
2865	>	TreeNode<K,V> r, p;
2866	>	try {
2867	>	p = ((r = root) == null ? null :
2868	>	r.findTreeNode(h, k, null));
2869	>	} finally {
2870	>	Thread w;
2871	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2872	>	(READER|WAITER) && (w = waiter) != null)
2873	>	LockSupport.unpark(w);
2874	>	}
2875	>	return p;
2876	>	}
2877	>	}
2878	>	}
2879	>	return null;
2880	>	}
2881	>
2882	>	/**
2883	>	* Finds or adds a node.
2884	>	* @return null if added
2885	>	*/
2886	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2887	>	Class<?> kc = null;
2888	>	boolean searched = false;
2889	>	for (TreeNode<K,V> p = root;;) {
2890	>	int dir, ph; K pk;
2891	>	if (p == null) {
2892	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2893	>	break;
2894	>	}
2895	>	else if ((ph = p.hash) > h)
2896	>	dir = -1;
2897	>	else if (ph < h)
2898	>	dir = 1;
2899	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2900	>	return p;
2901	>	else if ((kc == null &&
2902	>	(kc = comparableClassFor(k)) == null) ||
2903	>	(dir = compareComparables(kc, k, pk)) == 0) {
2904	>	if (!searched) {
2905	>	TreeNode<K,V> q, ch;
2906	>	searched = true;
2907	>	if (((ch = p.left) != null &&
2908	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2909	>	((ch = p.right) != null &&
2910	>	(q = ch.findTreeNode(h, k, kc)) != null))
2911	>	return q;
2912	>	}
2913	>	dir = tieBreakOrder(k, pk);
2914	>	}
2915	>
2916	>	TreeNode<K,V> xp = p;
2917	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2918	>	TreeNode<K,V> x, f = first;
2919	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2920	>	if (f != null)
2921	>	f.prev = x;
2922	>	if (dir <= 0)
2923	>	xp.left = x;
2924	>	else
2925	>	xp.right = x;
2926	>	if (!xp.red)
2927	>	x.red = true;
2928	>	else {
2929	>	lockRoot();
2930	>	try {
2931	>	root = balanceInsertion(root, x);
2932	>	} finally {
2933	>	unlockRoot();
2934	>	}
2935	>	}
2936	>	break;
2937	>	}
2938	>	}
2939	>	assert checkInvariants(root);
2940	>	return null;
2941	>	}
2942	>
2943	>	/**
2944	>	* Removes the given node, that must be present before this
2945	>	* call.  This is messier than typical red-black deletion code
2946	>	* because we cannot swap the contents of an interior node
2947	>	* with a leaf successor that is pinned by "next" pointers
2948	>	* that are accessible independently of lock. So instead we
2949	>	* swap the tree linkages.
2950	>	*
2951	>	* @return true if now too small, so should be untreeified
2952	>	*/
2953	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2954	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2955	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2956	>	TreeNode<K,V> r, rl;
2957	>	if (pred == null)
2958	>	first = next;
2959	>	else
2960	>	pred.next = next;
2961	>	if (next != null)
2962	>	next.prev = pred;
2963	>	if (first == null) {
2964	>	root = null;
2965	>	return true;
2966	>	}
2967	>	if ((r = root) == null || r.right == null || // too small
2968	>	(rl = r.left) == null || rl.left == null)
2969	>	return true;
2970	>	lockRoot();
2971	>	try {
2972	>	TreeNode<K,V> replacement;
2973	>	TreeNode<K,V> pl = p.left;
2974	>	TreeNode<K,V> pr = p.right;
2975	>	if (pl != null && pr != null) {
2976	>	TreeNode<K,V> s = pr, sl;
2977	>	while ((sl = s.left) != null) // find successor
2978	>	s = sl;
2979	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2980	>	TreeNode<K,V> sr = s.right;
2981	>	TreeNode<K,V> pp = p.parent;
2982	>	if (s == pr) { // p was s's direct parent
2983	>	p.parent = s;
2984	>	s.right = p;
2985	>	}
2986	>	else {
2987	>	TreeNode<K,V> sp = s.parent;
2988	>	if ((p.parent = sp) != null) {
2989	>	if (s == sp.left)
2990	>	sp.left = p;
2991	>	else
2992	>	sp.right = p;
2993	>	}
2994	>	if ((s.right = pr) != null)
2995	>	pr.parent = s;
2996	>	}
2997	>	p.left = null;
2998	>	if ((p.right = sr) != null)
2999	>	sr.parent = p;
3000	>	if ((s.left = pl) != null)
3001	>	pl.parent = s;
3002	>	if ((s.parent = pp) == null)
3003	>	r = s;
3004	>	else if (p == pp.left)
3005	>	pp.left = s;
3006	>	else
3007	>	pp.right = s;
3008	>	if (sr != null)
3009	>	replacement = sr;
3010	>	else
3011	>	replacement = p;
3012	>	}
3013	>	else if (pl != null)
3014	>	replacement = pl;
3015	>	else if (pr != null)
3016	>	replacement = pr;
3017	>	else
3018	>	replacement = p;
3019	>	if (replacement != p) {
3020	>	TreeNode<K,V> pp = replacement.parent = p.parent;
3021	>	if (pp == null)
3022	>	r = replacement;
3023	>	else if (p == pp.left)
3024	>	pp.left = replacement;
3025	>	else
3026	>	pp.right = replacement;
3027	>	p.left = p.right = p.parent = null;
3028	>	}
3029	>
3030	>	root = (p.red) ? r : balanceDeletion(r, replacement);
3031	>
3032	>	if (p == replacement) {  // detach pointers
3033	>	TreeNode<K,V> pp;
3034	>	if ((pp = p.parent) != null) {
3035	>	if (p == pp.left)
3036	>	pp.left = null;
3037	>	else if (p == pp.right)
3038	>	pp.right = null;
3039	>	p.parent = null;
3040	>	}
3041	>	}
3042	>	} finally {
3043	>	unlockRoot();
3044	>	}
3045	>	assert checkInvariants(root);
3046	>	return false;
3047	>	}
3048	>
3049	>	/* ------------------------------------------------------------ */
3050	>	// Red-black tree methods, all adapted from CLR
3051	>
3052	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3053	>	TreeNode<K,V> p) {
3054	>	TreeNode<K,V> r, pp, rl;
3055	>	if (p != null && (r = p.right) != null) {
3056	>	if ((rl = p.right = r.left) != null)
3057	>	rl.parent = p;
3058	>	if ((pp = r.parent = p.parent) == null)
3059	>	(root = r).red = false;
3060	>	else if (pp.left == p)
3061	>	pp.left = r;
3062		else
3063	<	return (int)sum;
3063	>	pp.right = r;
3064	>	r.left = p;
3065	>	p.parent = r;
3066	>	}
3067	>	return root;
3068	>	}
3069	>
3070	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3071	>	TreeNode<K,V> p) {
3072	>	TreeNode<K,V> l, pp, lr;
3073	>	if (p != null && (l = p.left) != null) {
3074	>	if ((lr = p.left = l.right) != null)
3075	>	lr.parent = p;
3076	>	if ((pp = l.parent = p.parent) == null)
3077	>	(root = l).red = false;
3078	>	else if (pp.right == p)
3079	>	pp.right = l;
3080	>	else
3081	>	pp.left = l;
3082	>	l.right = p;
3083	>	p.parent = l;
3084	>	}
3085	>	return root;
3086	>	}
3087	>
3088	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3089	>	TreeNode<K,V> x) {
3090	>	x.red = true;
3091	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3092	>	if ((xp = x.parent) == null) {
3093	>	x.red = false;
3094	>	return x;
3095	>	}
3096	>	else if (!xp.red || (xpp = xp.parent) == null)
3097	>	return root;
3098	>	if (xp == (xppl = xpp.left)) {
3099	>	if ((xppr = xpp.right) != null && xppr.red) {
3100	>	xppr.red = false;
3101	>	xp.red = false;
3102	>	xpp.red = true;
3103	>	x = xpp;
3104	>	}
3105	>	else {
3106	>	if (x == xp.right) {
3107	>	root = rotateLeft(root, x = xp);
3108	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3109	>	}
3110	>	if (xp != null) {
3111	>	xp.red = false;
3112	>	if (xpp != null) {
3113	>	xpp.red = true;
3114	>	root = rotateRight(root, xpp);
3115	>	}
3116	>	}
3117	>	}
3118	>	}
3119	>	else {
3120	>	if (xppl != null && xppl.red) {
3121	>	xppl.red = false;
3122	>	xp.red = false;
3123	>	xpp.red = true;
3124	>	x = xpp;
3125	>	}
3126	>	else {
3127	>	if (x == xp.left) {
3128	>	root = rotateRight(root, x = xp);
3129	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3130	>	}
3131	>	if (xp != null) {
3132	>	xp.red = false;
3133	>	if (xpp != null) {
3134	>	xpp.red = true;
3135	>	root = rotateLeft(root, xpp);
3136	>	}
3137	>	}
3138	>	}
3139	>	}
3140		}
3141		}
3142	+
3143	+	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3144	+	TreeNode<K,V> x) {
3145	+	for (TreeNode<K,V> xp, xpl, xpr;;) {
3146	+	if (x == null || x == root)
3147	+	return root;
3148	+	else if ((xp = x.parent) == null) {
3149	+	x.red = false;
3150	+	return x;
3151	+	}
3152	+	else if (x.red) {
3153	+	x.red = false;
3154	+	return root;
3155	+	}
3156	+	else if ((xpl = xp.left) == x) {
3157	+	if ((xpr = xp.right) != null && xpr.red) {
3158	+	xpr.red = false;
3159	+	xp.red = true;
3160	+	root = rotateLeft(root, xp);
3161	+	xpr = (xp = x.parent) == null ? null : xp.right;
3162	+	}
3163	+	if (xpr == null)
3164	+	x = xp;
3165	+	else {
3166	+	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3167	+	if ((sr == null || !sr.red) &&
3168	+	(sl == null || !sl.red)) {
3169	+	xpr.red = true;
3170	+	x = xp;
3171	+	}
3172	+	else {
3173	+	if (sr == null || !sr.red) {
3174	+	if (sl != null)
3175	+	sl.red = false;
3176	+	xpr.red = true;
3177	+	root = rotateRight(root, xpr);
3178	+	xpr = (xp = x.parent) == null ?
3179	+	null : xp.right;
3180	+	}
3181	+	if (xpr != null) {
3182	+	xpr.red = (xp == null) ? false : xp.red;
3183	+	if ((sr = xpr.right) != null)
3184	+	sr.red = false;
3185	+	}
3186	+	if (xp != null) {
3187	+	xp.red = false;
3188	+	root = rotateLeft(root, xp);
3189	+	}
3190	+	x = root;
3191	+	}
3192	+	}
3193	+	}
3194	+	else { // symmetric
3195	+	if (xpl != null && xpl.red) {
3196	+	xpl.red = false;
3197	+	xp.red = true;
3198	+	root = rotateRight(root, xp);
3199	+	xpl = (xp = x.parent) == null ? null : xp.left;
3200	+	}
3201	+	if (xpl == null)
3202	+	x = xp;
3203	+	else {
3204	+	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3205	+	if ((sl == null || !sl.red) &&
3206	+	(sr == null || !sr.red)) {
3207	+	xpl.red = true;
3208	+	x = xp;
3209	+	}
3210	+	else {
3211	+	if (sl == null || !sl.red) {
3212	+	if (sr != null)
3213	+	sr.red = false;
3214	+	xpl.red = true;
3215	+	root = rotateLeft(root, xpl);
3216	+	xpl = (xp = x.parent) == null ?
3217	+	null : xp.left;
3218	+	}
3219	+	if (xpl != null) {
3220	+	xpl.red = (xp == null) ? false : xp.red;
3221	+	if ((sl = xpl.left) != null)
3222	+	sl.red = false;
3223	+	}
3224	+	if (xp != null) {
3225	+	xp.red = false;
3226	+	root = rotateRight(root, xp);
3227	+	}
3228	+	x = root;
3229	+	}
3230	+	}
3231	+	}
3232	+	}
3233	+	}
3234	+
3235	+	/**
3236	+	* Checks invariants recursively for the tree of Nodes rooted at t.
3237	+	*/
3238	+	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3239	+	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3240	+	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3241	+	if (tb != null && tb.next != t)
3242	+	return false;
3243	+	if (tn != null && tn.prev != t)
3244	+	return false;
3245	+	if (tp != null && t != tp.left && t != tp.right)
3246	+	return false;
3247	+	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3248	+	return false;
3249	+	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3250	+	return false;
3251	+	if (t.red && tl != null && tl.red && tr != null && tr.red)
3252	+	return false;
3253	+	if (tl != null && !checkInvariants(tl))
3254	+	return false;
3255	+	if (tr != null && !checkInvariants(tr))
3256	+	return false;
3257	+	return true;
3258	+	}
3259	+
3260	+	private static final Unsafe U = Unsafe.getUnsafe();
3261	+	private static final long LOCKSTATE
3262	+	= U.objectFieldOffset(TreeBin.class, "lockState");
3263		}
3264
3265	+	/* ----------------Table Traversal -------------- */
3266	+
3267	+	/**
3268	+	* Records the table, its length, and current traversal index for a
3269	+	* traverser that must process a region of a forwarded table before
3270	+	* proceeding with current table.
3271	+	*/
3272	+	static final class TableStack<K,V> {
3273	+	int length;
3274	+	int index;
3275	+	Node<K,V>[] tab;
3276	+	TableStack<K,V> next;
3277	+	}
3278
3279		/**
3280	<	* Returns the value to which the specified key is mapped in this table.
3280	>	* Encapsulates traversal for methods such as containsValue; also
3281	>	* serves as a base class for other iterators and spliterators.
3282	>	*
3283	>	* Method advance visits once each still-valid node that was
3284	>	* reachable upon iterator construction. It might miss some that
3285	>	* were added to a bin after the bin was visited, which is OK wrt
3286	>	* consistency guarantees. Maintaining this property in the face
3287	>	* of possible ongoing resizes requires a fair amount of
3288	>	* bookkeeping state that is difficult to optimize away amidst
3289	>	* volatile accesses.  Even so, traversal maintains reasonable
3290	>	* throughput.
3291		*
3292	<	* @param   key   a key in the table.
3293	<	* @return  the value to which the key is mapped in this table;
3294	<	*          <tt>null</tt> if the key is not mapped to any value in
3295	<	*          this table.
3296	<	* @throws  NullPointerException  if the key is
3297	<	*               <tt>null</tt>.
3292	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3293	>	* However, if the table has been resized, then all future steps
3294	>	* must traverse both the bin at the current index as well as at
3295	>	* (index + baseSize); and so on for further resizings. To
3296	>	* paranoically cope with potential sharing by users of iterators
3297	>	* across threads, iteration terminates if a bounds checks fails
3298	>	* for a table read.
3299		*/
3300	<	public V get(Object key) {
3301	<	int hash = hash(key); // throws NullPointerException if key null
3302	<	return segmentFor(hash).get(key, hash);
3300	>	static class Traverser<K,V> {
3301	>	Node<K,V>[] tab;        // current table; updated if resized
3302	>	Node<K,V> next;         // the next entry to use
3303	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3304	>	int index;              // index of bin to use next
3305	>	int baseIndex;          // current index of initial table
3306	>	int baseLimit;          // index bound for initial table
3307	>	final int baseSize;     // initial table size
3308	>
3309	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3310	>	this.tab = tab;
3311	>	this.baseSize = size;
3312	>	this.baseIndex = this.index = index;
3313	>	this.baseLimit = limit;
3314	>	this.next = null;
3315	>	}
3316	>
3317	>	/**
3318	>	* Advances if possible, returning next valid node, or null if none.
3319	>	*/
3320	>	final Node<K,V> advance() {
3321	>	Node<K,V> e;
3322	>	if ((e = next) != null)
3323	>	e = e.next;
3324	>	for (;;) {
3325	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3326	>	if (e != null)
3327	>	return next = e;
3328	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3329	>	(n = t.length) <= (i = index) || i < 0)
3330	>	return next = null;
3331	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3332	>	if (e instanceof ForwardingNode) {
3333	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3334	>	e = null;
3335	>	pushState(t, i, n);
3336	>	continue;
3337	>	}
3338	>	else if (e instanceof TreeBin)
3339	>	e = ((TreeBin<K,V>)e).first;
3340	>	else
3341	>	e = null;
3342	>	}
3343	>	if (stack != null)
3344	>	recoverState(n);
3345	>	else if ((index = i + baseSize) >= n)
3346	>	index = ++baseIndex; // visit upper slots if present
3347	>	}
3348	>	}
3349	>
3350	>	/**
3351	>	* Saves traversal state upon encountering a forwarding node.
3352	>	*/
3353	>	private void pushState(Node<K,V>[] t, int i, int n) {
3354	>	TableStack<K,V> s = spare;  // reuse if possible
3355	>	if (s != null)
3356	>	spare = s.next;
3357	>	else
3358	>	s = new TableStack<K,V>();
3359	>	s.tab = t;
3360	>	s.length = n;
3361	>	s.index = i;
3362	>	s.next = stack;
3363	>	stack = s;
3364	>	}
3365	>
3366	>	/**
3367	>	* Possibly pops traversal state.
3368	>	*
3369	>	* @param n length of current table
3370	>	*/
3371	>	private void recoverState(int n) {
3372	>	TableStack<K,V> s; int len;
3373	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3374	>	n = len;
3375	>	index = s.index;
3376	>	tab = s.tab;
3377	>	s.tab = null;
3378	>	TableStack<K,V> next = s.next;
3379	>	s.next = spare; // save for reuse
3380	>	stack = next;
3381	>	spare = s;
3382	>	}
3383	>	if (s == null && (index += baseSize) >= n)
3384	>	index = ++baseIndex;
3385	>	}
3386		}
3387
3388		/**
3389	<	* Tests if the specified object is a key in this table.
3389	>	* Base of key, value, and entry Iterators. Adds fields to
3390	>	* Traverser to support iterator.remove.
3391	>	*/
3392	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3393	>	final ConcurrentHashMap<K,V> map;
3394	>	Node<K,V> lastReturned;
3395	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3396	>	ConcurrentHashMap<K,V> map) {
3397	>	super(tab, size, index, limit);
3398	>	this.map = map;
3399	>	advance();
3400	>	}
3401	>
3402	>	public final boolean hasNext() { return next != null; }
3403	>	public final boolean hasMoreElements() { return next != null; }
3404	>
3405	>	public final void remove() {
3406	>	Node<K,V> p;
3407	>	if ((p = lastReturned) == null)
3408	>	throw new IllegalStateException();
3409	>	lastReturned = null;
3410	>	map.replaceNode(p.key, null, null);
3411	>	}
3412	>	}
3413	>
3414	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3415	>	implements Iterator<K>, Enumeration<K> {
3416	>	KeyIterator(Node<K,V>[] tab, int size, int index, int limit,
3417	>	ConcurrentHashMap<K,V> map) {
3418	>	super(tab, size, index, limit, map);
3419	>	}
3420	>
3421	>	public final K next() {
3422	>	Node<K,V> p;
3423	>	if ((p = next) == null)
3424	>	throw new NoSuchElementException();
3425	>	K k = p.key;
3426	>	lastReturned = p;
3427	>	advance();
3428	>	return k;
3429	>	}
3430	>
3431	>	public final K nextElement() { return next(); }
3432	>	}
3433	>
3434	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3435	>	implements Iterator<V>, Enumeration<V> {
3436	>	ValueIterator(Node<K,V>[] tab, int size, int index, int limit,
3437	>	ConcurrentHashMap<K,V> map) {
3438	>	super(tab, size, index, limit, map);
3439	>	}
3440	>
3441	>	public final V next() {
3442	>	Node<K,V> p;
3443	>	if ((p = next) == null)
3444	>	throw new NoSuchElementException();
3445	>	V v = p.val;
3446	>	lastReturned = p;
3447	>	advance();
3448	>	return v;
3449	>	}
3450	>
3451	>	public final V nextElement() { return next(); }
3452	>	}
3453	>
3454	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3455	>	implements Iterator<Map.Entry<K,V>> {
3456	>	EntryIterator(Node<K,V>[] tab, int size, int index, int limit,
3457	>	ConcurrentHashMap<K,V> map) {
3458	>	super(tab, size, index, limit, map);
3459	>	}
3460	>
3461	>	public final Map.Entry<K,V> next() {
3462	>	Node<K,V> p;
3463	>	if ((p = next) == null)
3464	>	throw new NoSuchElementException();
3465	>	K k = p.key;
3466	>	V v = p.val;
3467	>	lastReturned = p;
3468	>	advance();
3469	>	return new MapEntry<K,V>(k, v, map);
3470	>	}
3471	>	}
3472	>
3473	>	/**
3474	>	* Exported Entry for EntryIterator.
3475	>	*/
3476	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3477	>	final K key; // non-null
3478	>	V val;       // non-null
3479	>	final ConcurrentHashMap<K,V> map;
3480	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3481	>	this.key = key;
3482	>	this.val = val;
3483	>	this.map = map;
3484	>	}
3485	>	public K getKey()        { return key; }
3486	>	public V getValue()      { return val; }
3487	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3488	>	public String toString() {
3489	>	return Helpers.mapEntryToString(key, val);
3490	>	}
3491	>
3492	>	public boolean equals(Object o) {
3493	>	Object k, v; Map.Entry<?,?> e;
3494	>	return ((o instanceof Map.Entry) &&
3495	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3496	>	(v = e.getValue()) != null &&
3497	>	(k == key || k.equals(key)) &&
3498	>	(v == val || v.equals(val)));
3499	>	}
3500	>
3501	>	/**
3502	>	* Sets our entry's value and writes through to the map. The
3503	>	* value to return is somewhat arbitrary here. Since we do not
3504	>	* necessarily track asynchronous changes, the most recent
3505	>	* "previous" value could be different from what we return (or
3506	>	* could even have been removed, in which case the put will
3507	>	* re-establish). We do not and cannot guarantee more.
3508	>	*/
3509	>	public V setValue(V value) {
3510	>	if (value == null) throw new NullPointerException();
3511	>	V v = val;
3512	>	val = value;
3513	>	map.put(key, value);
3514	>	return v;
3515	>	}
3516	>	}
3517	>
3518	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3519	>	implements Spliterator<K> {
3520	>	long est;               // size estimate
3521	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3522	>	long est) {
3523	>	super(tab, size, index, limit);
3524	>	this.est = est;
3525	>	}
3526	>
3527	>	public KeySpliterator<K,V> trySplit() {
3528	>	int i, f, h;
3529	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3530	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3531	>	f, est >>>= 1);
3532	>	}
3533	>
3534	>	public void forEachRemaining(Consumer<? super K> action) {
3535	>	if (action == null) throw new NullPointerException();
3536	>	for (Node<K,V> p; (p = advance()) != null;)
3537	>	action.accept(p.key);
3538	>	}
3539	>
3540	>	public boolean tryAdvance(Consumer<? super K> action) {
3541	>	if (action == null) throw new NullPointerException();
3542	>	Node<K,V> p;
3543	>	if ((p = advance()) == null)
3544	>	return false;
3545	>	action.accept(p.key);
3546	>	return true;
3547	>	}
3548	>
3549	>	public long estimateSize() { return est; }
3550	>
3551	>	public int characteristics() {
3552	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3553	>	Spliterator.NONNULL;
3554	>	}
3555	>	}
3556	>
3557	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3558	>	implements Spliterator<V> {
3559	>	long est;               // size estimate
3560	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3561	>	long est) {
3562	>	super(tab, size, index, limit);
3563	>	this.est = est;
3564	>	}
3565	>
3566	>	public ValueSpliterator<K,V> trySplit() {
3567	>	int i, f, h;
3568	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3569	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3570	>	f, est >>>= 1);
3571	>	}
3572	>
3573	>	public void forEachRemaining(Consumer<? super V> action) {
3574	>	if (action == null) throw new NullPointerException();
3575	>	for (Node<K,V> p; (p = advance()) != null;)
3576	>	action.accept(p.val);
3577	>	}
3578	>
3579	>	public boolean tryAdvance(Consumer<? super V> action) {
3580	>	if (action == null) throw new NullPointerException();
3581	>	Node<K,V> p;
3582	>	if ((p = advance()) == null)
3583	>	return false;
3584	>	action.accept(p.val);
3585	>	return true;
3586	>	}
3587	>
3588	>	public long estimateSize() { return est; }
3589	>
3590	>	public int characteristics() {
3591	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3592	>	}
3593	>	}
3594	>
3595	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3596	>	implements Spliterator<Map.Entry<K,V>> {
3597	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3598	>	long est;               // size estimate
3599	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3600	>	long est, ConcurrentHashMap<K,V> map) {
3601	>	super(tab, size, index, limit);
3602	>	this.map = map;
3603	>	this.est = est;
3604	>	}
3605	>
3606	>	public EntrySpliterator<K,V> trySplit() {
3607	>	int i, f, h;
3608	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3609	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3610	>	f, est >>>= 1, map);
3611	>	}
3612	>
3613	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3614	>	if (action == null) throw new NullPointerException();
3615	>	for (Node<K,V> p; (p = advance()) != null; )
3616	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3617	>	}
3618	>
3619	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3620	>	if (action == null) throw new NullPointerException();
3621	>	Node<K,V> p;
3622	>	if ((p = advance()) == null)
3623	>	return false;
3624	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3625	>	return true;
3626	>	}
3627	>
3628	>	public long estimateSize() { return est; }
3629	>
3630	>	public int characteristics() {
3631	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3632	>	Spliterator.NONNULL;
3633	>	}
3634	>	}
3635	>
3636	>	// Parallel bulk operations
3637	>
3638	>	/**
3639	>	* Computes initial batch value for bulk tasks. The returned value
3640	>	* is approximately exp2 of the number of times (minus one) to
3641	>	* split task by two before executing leaf action. This value is
3642	>	* faster to compute and more convenient to use as a guide to
3643	>	* splitting than is the depth, since it is used while dividing by
3644	>	* two anyway.
3645	>	*/
3646	>	final int batchFor(long b) {
3647	>	long n;
3648	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3649	>	return 0;
3650	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3651	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3652	>	}
3653	>
3654	>	/**
3655	>	* Performs the given action for each (key, value).
3656		*
3657	<	* @param   key   possible key.
3658	<	* @return  <tt>true</tt> if and only if the specified object
3659	<	*          is a key in this table, as determined by the
3660	<	*          <tt>equals</tt> method; <tt>false</tt> otherwise.
681	<	* @throws  NullPointerException  if the key is
682	<	*               <tt>null</tt>.
3657	>	* @param parallelismThreshold the (estimated) number of elements
3658	>	* needed for this operation to be executed in parallel
3659	>	* @param action the action
3660	>	* @since 1.8
3661		*/
3662	<	public boolean containsKey(Object key) {
3663	<	int hash = hash(key); // throws NullPointerException if key null
3664	<	return segmentFor(hash).containsKey(key, hash);
3662	>	public void forEach(long parallelismThreshold,
3663	>	BiConsumer<? super K,? super V> action) {
3664	>	if (action == null) throw new NullPointerException();
3665	>	new ForEachMappingTask<K,V>
3666	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3667	>	action).invoke();
3668		}
3669
3670		/**
3671	<	* Returns <tt>true</tt> if this map maps one or more keys to the
3672	<	* specified value. Note: This method requires a full internal
692	<	* traversal of the hash table, and so is much slower than
693	<	* method <tt>containsKey</tt>.
3671	>	* Performs the given action for each non-null transformation
3672	>	* of each (key, value).
3673		*
3674	<	* @param value value whose presence in this map is to be tested.
3675	<	* @return <tt>true</tt> if this map maps one or more keys to the
3676	<	* specified value.
3677	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3674	>	* @param parallelismThreshold the (estimated) number of elements
3675	>	* needed for this operation to be executed in parallel
3676	>	* @param transformer a function returning the transformation
3677	>	* for an element, or null if there is no transformation (in
3678	>	* which case the action is not applied)
3679	>	* @param action the action
3680	>	* @param <U> the return type of the transformer
3681	>	* @since 1.8
3682		*/
3683	<	public boolean containsValue(Object value) {
3684	<	if (value == null)
3683	>	public <U> void forEach(long parallelismThreshold,
3684	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3685	>	Consumer<? super U> action) {
3686	>	if (transformer == null || action == null)
3687		throw new NullPointerException();
3688	+	new ForEachTransformedMappingTask<K,V,U>
3689	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3690	+	transformer, action).invoke();
3691	+	}
3692
3693	<	final Segment[] segments = this.segments;
3694	<	int[] mc = new int[segments.length];
3695	<	for (;;) {
3696	<	int sum = 0;
3697	<	int mcsum = 0;
3698	<	for (int i = 0; i < segments.length; ++i) {
3699	<	int c = segments[i].count;
3700	<	mcsum += mc[i] = segments[i].modCount;
3701	<	if (segments[i].containsValue(value))
3702	<	return true;
3703	<	}
3704	<	boolean cleanSweep = true;
3705	<	if (mcsum != 0) {
3706	<	for (int i = 0; i < segments.length; ++i) {
3707	<	int c = segments[i].count;
3708	<	if (mc[i] != segments[i].modCount) {
3709	<	cleanSweep = false;
3710	<	break;
3711	<	}
3712	<	}
3713	<	}
3714	<	if (cleanSweep)
726	<	return false;
727	<	}
3693	>	/**
3694	>	* Returns a non-null result from applying the given search
3695	>	* function on each (key, value), or null if none.  Upon
3696	>	* success, further element processing is suppressed and the
3697	>	* results of any other parallel invocations of the search
3698	>	* function are ignored.
3699	>	*
3700	>	* @param parallelismThreshold the (estimated) number of elements
3701	>	* needed for this operation to be executed in parallel
3702	>	* @param searchFunction a function returning a non-null
3703	>	* result on success, else null
3704	>	* @param <U> the return type of the search function
3705	>	* @return a non-null result from applying the given search
3706	>	* function on each (key, value), or null if none
3707	>	* @since 1.8
3708	>	*/
3709	>	public <U> U search(long parallelismThreshold,
3710	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3711	>	if (searchFunction == null) throw new NullPointerException();
3712	>	return new SearchMappingsTask<K,V,U>
3713	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3714	>	searchFunction, new AtomicReference<U>()).invoke();
3715		}
3716
3717		/**
3718	<	* Legacy method testing if some key maps into the specified value
3719	<	* in this table.  This method is identical in functionality to
3720	<	* {@link #containsValue}, and  exists solely to ensure
3721	<	* full compatibility with class {@link java.util.Hashtable},
3722	<	* which supported this method prior to introduction of the
3723	<	* Java Collections framework.
3718	>	* Returns the result of accumulating the given transformation
3719	>	* of all (key, value) pairs using the given reducer to
3720	>	* combine values, or null if none.
3721	>	*
3722	>	* @param parallelismThreshold the (estimated) number of elements
3723	>	* needed for this operation to be executed in parallel
3724	>	* @param transformer a function returning the transformation
3725	>	* for an element, or null if there is no transformation (in
3726	>	* which case it is not combined)
3727	>	* @param reducer a commutative associative combining function
3728	>	* @param <U> the return type of the transformer
3729	>	* @return the result of accumulating the given transformation
3730	>	* of all (key, value) pairs
3731	>	* @since 1.8
3732	>	*/
3733	>	public <U> U reduce(long parallelismThreshold,
3734	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3735	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3736	>	if (transformer == null || reducer == null)
3737	>	throw new NullPointerException();
3738	>	return new MapReduceMappingsTask<K,V,U>
3739	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3740	>	null, transformer, reducer).invoke();
3741	>	}
3742
3743	<	* @param      value   a value to search for.
3744	<	* @return     <tt>true</tt> if and only if some key maps to the
3745	<	*             <tt>value</tt> argument in this table as
3746	<	*             determined by the <tt>equals</tt> method;
3747	<	*             <tt>false</tt> otherwise.
3748	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3743	>	/**
3744	>	* Returns the result of accumulating the given transformation
3745	>	* of all (key, value) pairs using the given reducer to
3746	>	* combine values, and the given basis as an identity value.
3747	>	*
3748	>	* @param parallelismThreshold the (estimated) number of elements
3749	>	* needed for this operation to be executed in parallel
3750	>	* @param transformer a function returning the transformation
3751	>	* for an element
3752	>	* @param basis the identity (initial default value) for the reduction
3753	>	* @param reducer a commutative associative combining function
3754	>	* @return the result of accumulating the given transformation
3755	>	* of all (key, value) pairs
3756	>	* @since 1.8
3757		*/
3758	<	public boolean contains(Object value) {
3759	<	return containsValue(value);
3758	>	public double reduceToDouble(long parallelismThreshold,
3759	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3760	>	double basis,
3761	>	DoubleBinaryOperator reducer) {
3762	>	if (transformer == null || reducer == null)
3763	>	throw new NullPointerException();
3764	>	return new MapReduceMappingsToDoubleTask<K,V>
3765	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3766	>	null, transformer, basis, reducer).invoke();
3767		}
3768
3769		/**
3770	<	* Maps the specified <tt>key</tt> to the specified
3771	<	* <tt>value</tt> in this table. Neither the key nor the
3772	<	* value can be <tt>null</tt>. <p>
3770	>	* Returns the result of accumulating the given transformation
3771	>	* of all (key, value) pairs using the given reducer to
3772	>	* combine values, and the given basis as an identity value.
3773		*
3774	<	* The value can be retrieved by calling the <tt>get</tt> method
3775	<	* with a key that is equal to the original key.
3774	>	* @param parallelismThreshold the (estimated) number of elements
3775	>	* needed for this operation to be executed in parallel
3776	>	* @param transformer a function returning the transformation
3777	>	* for an element
3778	>	* @param basis the identity (initial default value) for the reduction
3779	>	* @param reducer a commutative associative combining function
3780	>	* @return the result of accumulating the given transformation
3781	>	* of all (key, value) pairs
3782	>	* @since 1.8
3783	>	*/
3784	>	public long reduceToLong(long parallelismThreshold,
3785	>	ToLongBiFunction<? super K, ? super V> transformer,
3786	>	long basis,
3787	>	LongBinaryOperator reducer) {
3788	>	if (transformer == null || reducer == null)
3789	>	throw new NullPointerException();
3790	>	return new MapReduceMappingsToLongTask<K,V>
3791	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3792	>	null, transformer, basis, reducer).invoke();
3793	>	}
3794	>
3795	>	/**
3796	>	* Returns the result of accumulating the given transformation
3797	>	* of all (key, value) pairs using the given reducer to
3798	>	* combine values, and the given basis as an identity value.
3799		*
3800	<	* @param      key     the table key.
3801	<	* @param      value   the value.
3802	<	* @return     the previous value of the specified key in this table,
3803	<	*             or <tt>null</tt> if it did not have one.
3804	<	* @throws  NullPointerException  if the key or value is
3805	<	*               <tt>null</tt>.
3800	>	* @param parallelismThreshold the (estimated) number of elements
3801	>	* needed for this operation to be executed in parallel
3802	>	* @param transformer a function returning the transformation
3803	>	* for an element
3804	>	* @param basis the identity (initial default value) for the reduction
3805	>	* @param reducer a commutative associative combining function
3806	>	* @return the result of accumulating the given transformation
3807	>	* of all (key, value) pairs
3808	>	* @since 1.8
3809		*/
3810	<	public V put(K key, V value) {
3811	<	if (value == null)
3810	>	public int reduceToInt(long parallelismThreshold,
3811	>	ToIntBiFunction<? super K, ? super V> transformer,
3812	>	int basis,
3813	>	IntBinaryOperator reducer) {
3814	>	if (transformer == null || reducer == null)
3815		throw new NullPointerException();
3816	<	int hash = hash(key);
3817	<	return segmentFor(hash).put(key, hash, value, false);
3816	>	return new MapReduceMappingsToIntTask<K,V>
3817	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3818	>	null, transformer, basis, reducer).invoke();
3819		}
3820
3821		/**
3822	<	* If the specified key is not already associated
773	<	* with a value, associate it with the given value.
774	<	* This is equivalent to
775	<	* <pre>
776	<	*   if (!map.containsKey(key))
777	<	*      return map.put(key, value);
778	<	*   else
779	<	*      return map.get(key);
780	<	* </pre>
781	<	* Except that the action is performed atomically.
782	<	* @param key key with which the specified value is to be associated.
783	<	* @param value value to be associated with the specified key.
784	<	* @return previous value associated with specified key, or <tt>null</tt>
785	<	*         if there was no mapping for key.  A <tt>null</tt> return can
786	<	*         also indicate that the map previously associated <tt>null</tt>
787	<	*         with the specified key, if the implementation supports
788	<	*         <tt>null</tt> values.
789	<	*
790	<	* @throws UnsupportedOperationException if the <tt>put</tt> operation is
791	<	*            not supported by this map.
792	<	* @throws ClassCastException if the class of the specified key or value
793	<	*            prevents it from being stored in this map.
794	<	* @throws NullPointerException if the specified key or value is
795	<	*            <tt>null</tt>.
3822	>	* Performs the given action for each key.
3823		*
3824	<	**/
3825	<	public V putIfAbsent(K key, V value) {
3826	<	if (value == null)
3824	>	* @param parallelismThreshold the (estimated) number of elements
3825	>	* needed for this operation to be executed in parallel
3826	>	* @param action the action
3827	>	* @since 1.8
3828	>	*/
3829	>	public void forEachKey(long parallelismThreshold,
3830	>	Consumer<? super K> action) {
3831	>	if (action == null) throw new NullPointerException();
3832	>	new ForEachKeyTask<K,V>
3833	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3834	>	action).invoke();
3835	>	}
3836	>
3837	>	/**
3838	>	* Performs the given action for each non-null transformation
3839	>	* of each key.
3840	>	*
3841	>	* @param parallelismThreshold the (estimated) number of elements
3842	>	* needed for this operation to be executed in parallel
3843	>	* @param transformer a function returning the transformation
3844	>	* for an element, or null if there is no transformation (in
3845	>	* which case the action is not applied)
3846	>	* @param action the action
3847	>	* @param <U> the return type of the transformer
3848	>	* @since 1.8
3849	>	*/
3850	>	public <U> void forEachKey(long parallelismThreshold,
3851	>	Function<? super K, ? extends U> transformer,
3852	>	Consumer<? super U> action) {
3853	>	if (transformer == null || action == null)
3854		throw new NullPointerException();
3855	<	int hash = hash(key);
3856	<	return segmentFor(hash).put(key, hash, value, true);
3855	>	new ForEachTransformedKeyTask<K,V,U>
3856	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3857	>	transformer, action).invoke();
3858		}
3859
3860	+	/**
3861	+	* Returns a non-null result from applying the given search
3862	+	* function on each key, or null if none. Upon success,
3863	+	* further element processing is suppressed and the results of
3864	+	* any other parallel invocations of the search function are
3865	+	* ignored.
3866	+	*
3867	+	* @param parallelismThreshold the (estimated) number of elements
3868	+	* needed for this operation to be executed in parallel
3869	+	* @param searchFunction a function returning a non-null
3870	+	* result on success, else null
3871	+	* @param <U> the return type of the search function
3872	+	* @return a non-null result from applying the given search
3873	+	* function on each key, or null if none
3874	+	* @since 1.8
3875	+	*/
3876	+	public <U> U searchKeys(long parallelismThreshold,
3877	+	Function<? super K, ? extends U> searchFunction) {
3878	+	if (searchFunction == null) throw new NullPointerException();
3879	+	return new SearchKeysTask<K,V,U>
3880	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3881	+	searchFunction, new AtomicReference<U>()).invoke();
3882	+	}
3883
3884		/**
3885	<	* Copies all of the mappings from the specified map to this one.
3885	>	* Returns the result of accumulating all keys using the given
3886	>	* reducer to combine values, or null if none.
3887		*
3888	<	* These mappings replace any mappings that this map had for any of the
3889	<	* keys currently in the specified Map.
3888	>	* @param parallelismThreshold the (estimated) number of elements
3889	>	* needed for this operation to be executed in parallel
3890	>	* @param reducer a commutative associative combining function
3891	>	* @return the result of accumulating all keys using the given
3892	>	* reducer to combine values, or null if none
3893	>	* @since 1.8
3894	>	*/
3895	>	public K reduceKeys(long parallelismThreshold,
3896	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3897	>	if (reducer == null) throw new NullPointerException();
3898	>	return new ReduceKeysTask<K,V>
3899	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3900	>	null, reducer).invoke();
3901	>	}
3902	>
3903	>	/**
3904	>	* Returns the result of accumulating the given transformation
3905	>	* of all keys using the given reducer to combine values, or
3906	>	* null if none.
3907		*
3908	<	* @param t Mappings to be stored in this map.
3908	>	* @param parallelismThreshold the (estimated) number of elements
3909	>	* needed for this operation to be executed in parallel
3910	>	* @param transformer a function returning the transformation
3911	>	* for an element, or null if there is no transformation (in
3912	>	* which case it is not combined)
3913	>	* @param reducer a commutative associative combining function
3914	>	* @param <U> the return type of the transformer
3915	>	* @return the result of accumulating the given transformation
3916	>	* of all keys
3917	>	* @since 1.8
3918		*/
3919	<	public void putAll(Map<? extends K, ? extends V> t) {
3920	<	for (Iterator<Map.Entry<? extends K, ? extends V>> it = (Iterator<Map.Entry<? extends K, ? extends V>>) t.entrySet().iterator(); it.hasNext(); ) {
3921	<	Entry<? extends K, ? extends V> e = it.next();
3922	<	put(e.getKey(), e.getValue());
3923	<	}
3919	>	public <U> U reduceKeys(long parallelismThreshold,
3920	>	Function<? super K, ? extends U> transformer,
3921	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3922	>	if (transformer == null || reducer == null)
3923	>	throw new NullPointerException();
3924	>	return new MapReduceKeysTask<K,V,U>
3925	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3926	>	null, transformer, reducer).invoke();
3927		}
3928
3929		/**
3930	<	* Removes the key (and its corresponding value) from this
3931	<	* table. This method does nothing if the key is not in the table.
3930	>	* Returns the result of accumulating the given transformation
3931	>	* of all keys using the given reducer to combine values, and
3932	>	* the given basis as an identity value.
3933		*
3934	<	* @param   key   the key that needs to be removed.
3935	<	* @return  the value to which the key had been mapped in this table,
3936	<	*          or <tt>null</tt> if the key did not have a mapping.
3937	<	* @throws  NullPointerException  if the key is
3938	<	*               <tt>null</tt>.
3934	>	* @param parallelismThreshold the (estimated) number of elements
3935	>	* needed for this operation to be executed in parallel
3936	>	* @param transformer a function returning the transformation
3937	>	* for an element
3938	>	* @param basis the identity (initial default value) for the reduction
3939	>	* @param reducer a commutative associative combining function
3940	>	* @return the result of accumulating the given transformation
3941	>	* of all keys
3942	>	* @since 1.8
3943		*/
3944	<	public V remove(Object key) {
3945	<	int hash = hash(key);
3946	<	return segmentFor(hash).remove(key, hash, null);
3944	>	public double reduceKeysToDouble(long parallelismThreshold,
3945	>	ToDoubleFunction<? super K> transformer,
3946	>	double basis,
3947	>	DoubleBinaryOperator reducer) {
3948	>	if (transformer == null || reducer == null)
3949	>	throw new NullPointerException();
3950	>	return new MapReduceKeysToDoubleTask<K,V>
3951	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3952	>	null, transformer, basis, reducer).invoke();
3953		}
3954
3955		/**
3956	<	* Remove entry for key only if currently mapped to given value.
3957	<	* Acts as
3958	<	* <pre>
3959	<	*  if (map.get(key).equals(value)) {
3960	<	*     map.remove(key);
3961	<	*     return true;
3962	<	* } else return false;
3963	<	* </pre>
3964	<	* except that the action is performed atomically.
3965	<	* @param key key with which the specified value is associated.
3966	<	* @param value value associated with the specified key.
3967	<	* @return true if the value was removed
3968	<	* @throws NullPointerException if the specified key is
850	<	*            <tt>null</tt>.
3956	>	* Returns the result of accumulating the given transformation
3957	>	* of all keys using the given reducer to combine values, and
3958	>	* the given basis as an identity value.
3959	>	*
3960	>	* @param parallelismThreshold the (estimated) number of elements
3961	>	* needed for this operation to be executed in parallel
3962	>	* @param transformer a function returning the transformation
3963	>	* for an element
3964	>	* @param basis the identity (initial default value) for the reduction
3965	>	* @param reducer a commutative associative combining function
3966	>	* @return the result of accumulating the given transformation
3967	>	* of all keys
3968	>	* @since 1.8
3969		*/
3970	<	public boolean remove(Object key, Object value) {
3971	<	int hash = hash(key);
3972	<	return segmentFor(hash).remove(key, hash, value) != null;
3970	>	public long reduceKeysToLong(long parallelismThreshold,
3971	>	ToLongFunction<? super K> transformer,
3972	>	long basis,
3973	>	LongBinaryOperator reducer) {
3974	>	if (transformer == null || reducer == null)
3975	>	throw new NullPointerException();
3976	>	return new MapReduceKeysToLongTask<K,V>
3977	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3978	>	null, transformer, basis, reducer).invoke();
3979		}
3980
3981	+	/**
3982	+	* Returns the result of accumulating the given transformation
3983	+	* of all keys using the given reducer to combine values, and
3984	+	* the given basis as an identity value.
3985	+	*
3986	+	* @param parallelismThreshold the (estimated) number of elements
3987	+	* needed for this operation to be executed in parallel
3988	+	* @param transformer a function returning the transformation
3989	+	* for an element
3990	+	* @param basis the identity (initial default value) for the reduction
3991	+	* @param reducer a commutative associative combining function
3992	+	* @return the result of accumulating the given transformation
3993	+	* of all keys
3994	+	* @since 1.8
3995	+	*/
3996	+	public int reduceKeysToInt(long parallelismThreshold,
3997	+	ToIntFunction<? super K> transformer,
3998	+	int basis,
3999	+	IntBinaryOperator reducer) {
4000	+	if (transformer == null || reducer == null)
4001	+	throw new NullPointerException();
4002	+	return new MapReduceKeysToIntTask<K,V>
4003	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4004	+	null, transformer, basis, reducer).invoke();
4005	+	}
4006
4007		/**
4008	<	* Replace entry for key only if currently mapped to given value.
4009	<	* Acts as
4010	<	* <pre>
4011	<	*  if (map.get(key).equals(oldValue)) {
4012	<	*     map.put(key, newValue);
4013	<	*     return true;
865	<	* } else return false;
866	<	* </pre>
867	<	* except that the action is performed atomically.
868	<	* @param key key with which the specified value is associated.
869	<	* @param oldValue value expected to be associated with the specified key.
870	<	* @param newValue value to be associated with the specified key.
871	<	* @return true if the value was replaced
872	<	* @throws NullPointerException if the specified key or values are
873	<	* <tt>null</tt>.
4008	>	* Performs the given action for each value.
4009	>	*
4010	>	* @param parallelismThreshold the (estimated) number of elements
4011	>	* needed for this operation to be executed in parallel
4012	>	* @param action the action
4013	>	* @since 1.8
4014		*/
4015	<	public boolean replace(K key, V oldValue, V newValue) {
4016	<	if (oldValue == null || newValue == null)
4015	>	public void forEachValue(long parallelismThreshold,
4016	>	Consumer<? super V> action) {
4017	>	if (action == null)
4018		throw new NullPointerException();
4019	<	int hash = hash(key);
4020	<	return segmentFor(hash).replace(key, hash, oldValue, newValue);
4019	>	new ForEachValueTask<K,V>
4020	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4021	>	action).invoke();
4022		}
4023
4024		/**
4025	<	* Replace entry for key only if currently mapped to some value.
4026	<	* Acts as
4027	<	* <pre>
4028	<	*  if ((map.containsKey(key)) {
4029	<	*     return map.put(key, value);
4030	<	* } else return null;
4031	<	* </pre>
4032	<	* except that the action is performed atomically.
4033	<	* @param key key with which the specified value is associated.
4034	<	* @param value value to be associated with the specified key.
4035	<	* @return previous value associated with specified key, or <tt>null</tt>
894	<	*         if there was no mapping for key.
895	<	* @throws NullPointerException if the specified key or value is
896	<	*            <tt>null</tt>.
4025	>	* Performs the given action for each non-null transformation
4026	>	* of each value.
4027	>	*
4028	>	* @param parallelismThreshold the (estimated) number of elements
4029	>	* needed for this operation to be executed in parallel
4030	>	* @param transformer a function returning the transformation
4031	>	* for an element, or null if there is no transformation (in
4032	>	* which case the action is not applied)
4033	>	* @param action the action
4034	>	* @param <U> the return type of the transformer
4035	>	* @since 1.8
4036		*/
4037	<	public V replace(K key, V value) {
4038	<	if (value == null)
4037	>	public <U> void forEachValue(long parallelismThreshold,
4038	>	Function<? super V, ? extends U> transformer,
4039	>	Consumer<? super U> action) {
4040	>	if (transformer == null || action == null)
4041		throw new NullPointerException();
4042	<	int hash = hash(key);
4043	<	return segmentFor(hash).replace(key, hash, value);
4042	>	new ForEachTransformedValueTask<K,V,U>
4043	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4044	>	transformer, action).invoke();
4045		}
4046
4047	+	/**
4048	+	* Returns a non-null result from applying the given search
4049	+	* function on each value, or null if none.  Upon success,
4050	+	* further element processing is suppressed and the results of
4051	+	* any other parallel invocations of the search function are
4052	+	* ignored.
4053	+	*
4054	+	* @param parallelismThreshold the (estimated) number of elements
4055	+	* needed for this operation to be executed in parallel
4056	+	* @param searchFunction a function returning a non-null
4057	+	* result on success, else null
4058	+	* @param <U> the return type of the search function
4059	+	* @return a non-null result from applying the given search
4060	+	* function on each value, or null if none
4061	+	* @since 1.8
4062	+	*/
4063	+	public <U> U searchValues(long parallelismThreshold,
4064	+	Function<? super V, ? extends U> searchFunction) {
4065	+	if (searchFunction == null) throw new NullPointerException();
4066	+	return new SearchValuesTask<K,V,U>
4067	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4068	+	searchFunction, new AtomicReference<U>()).invoke();
4069	+	}
4070
4071		/**
4072	<	* Removes all mappings from this map.
4072	>	* Returns the result of accumulating all values using the
4073	>	* given reducer to combine values, or null if none.
4074	>	*
4075	>	* @param parallelismThreshold the (estimated) number of elements
4076	>	* needed for this operation to be executed in parallel
4077	>	* @param reducer a commutative associative combining function
4078	>	* @return the result of accumulating all values
4079	>	* @since 1.8
4080		*/
4081	<	public void clear() {
4082	<	for (int i = 0; i < segments.length; ++i)
4083	<	segments[i].clear();
4081	>	public V reduceValues(long parallelismThreshold,
4082	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4083	>	if (reducer == null) throw new NullPointerException();
4084	>	return new ReduceValuesTask<K,V>
4085	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4086	>	null, reducer).invoke();
4087		}
4088
4089	+	/**
4090	+	* Returns the result of accumulating the given transformation
4091	+	* of all values using the given reducer to combine values, or
4092	+	* null if none.
4093	+	*
4094	+	* @param parallelismThreshold the (estimated) number of elements
4095	+	* needed for this operation to be executed in parallel
4096	+	* @param transformer a function returning the transformation
4097	+	* for an element, or null if there is no transformation (in
4098	+	* which case it is not combined)
4099	+	* @param reducer a commutative associative combining function
4100	+	* @param <U> the return type of the transformer
4101	+	* @return the result of accumulating the given transformation
4102	+	* of all values
4103	+	* @since 1.8
4104	+	*/
4105	+	public <U> U reduceValues(long parallelismThreshold,
4106	+	Function<? super V, ? extends U> transformer,
4107	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4108	+	if (transformer == null || reducer == null)
4109	+	throw new NullPointerException();
4110	+	return new MapReduceValuesTask<K,V,U>
4111	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4112	+	null, transformer, reducer).invoke();
4113	+	}
4114
4115		/**
4116	<	* Returns a shallow copy of this
4117	<	* <tt>ConcurrentHashMap</tt> instance: the keys and
4118	<	* values themselves are not cloned.
4116	>	* Returns the result of accumulating the given transformation
4117	>	* of all values using the given reducer to combine values,
4118	>	* and the given basis as an identity value.
4119		*
4120	<	* @return a shallow copy of this map.
4120	>	* @param parallelismThreshold the (estimated) number of elements
4121	>	* needed for this operation to be executed in parallel
4122	>	* @param transformer a function returning the transformation
4123	>	* for an element
4124	>	* @param basis the identity (initial default value) for the reduction
4125	>	* @param reducer a commutative associative combining function
4126	>	* @return the result of accumulating the given transformation
4127	>	* of all values
4128	>	* @since 1.8
4129		*/
4130	<	public Object clone() {
4131	<	// We cannot call super.clone, since it would share final
4132	<	// segments array, and there's no way to reassign finals.
4130	>	public double reduceValuesToDouble(long parallelismThreshold,
4131	>	ToDoubleFunction<? super V> transformer,
4132	>	double basis,
4133	>	DoubleBinaryOperator reducer) {
4134	>	if (transformer == null || reducer == null)
4135	>	throw new NullPointerException();
4136	>	return new MapReduceValuesToDoubleTask<K,V>
4137	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4138	>	null, transformer, basis, reducer).invoke();
4139	>	}
4140
4141	<	float lf = segments[0].loadFactor;
4142	<	int segs = segments.length;
4143	<	int cap = (int)(size() / lf);
4144	<	if (cap < segs) cap = segs;
4145	<	ConcurrentHashMap<K,V> t = new ConcurrentHashMap<K,V>(cap, lf, segs);
4146	<	t.putAll(this);
4147	<	return t;
4141	>	/**
4142	>	* Returns the result of accumulating the given transformation
4143	>	* of all values using the given reducer to combine values,
4144	>	* and the given basis as an identity value.
4145	>	*
4146	>	* @param parallelismThreshold the (estimated) number of elements
4147	>	* needed for this operation to be executed in parallel
4148	>	* @param transformer a function returning the transformation
4149	>	* for an element
4150	>	* @param basis the identity (initial default value) for the reduction
4151	>	* @param reducer a commutative associative combining function
4152	>	* @return the result of accumulating the given transformation
4153	>	* of all values
4154	>	* @since 1.8
4155	>	*/
4156	>	public long reduceValuesToLong(long parallelismThreshold,
4157	>	ToLongFunction<? super V> transformer,
4158	>	long basis,
4159	>	LongBinaryOperator reducer) {
4160	>	if (transformer == null || reducer == null)
4161	>	throw new NullPointerException();
4162	>	return new MapReduceValuesToLongTask<K,V>
4163	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4164	>	null, transformer, basis, reducer).invoke();
4165		}
4166
4167		/**
4168	<	* Returns a set view of the keys contained in this map.  The set is
4169	<	* backed by the map, so changes to the map are reflected in the set, and
4170	<	* vice-versa.  The set supports element removal, which removes the
939	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
940	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
941	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
942	<	* <tt>addAll</tt> operations.
943	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
944	<	* will never throw {@link java.util.ConcurrentModificationException},
945	<	* and guarantees to traverse elements as they existed upon
946	<	* construction of the iterator, and may (but is not guaranteed to)
947	<	* reflect any modifications subsequent to construction.
4168	>	* Returns the result of accumulating the given transformation
4169	>	* of all values using the given reducer to combine values,
4170	>	* and the given basis as an identity value.
4171		*
4172	<	* @return a set view of the keys contained in this map.
4172	>	* @param parallelismThreshold the (estimated) number of elements
4173	>	* needed for this operation to be executed in parallel
4174	>	* @param transformer a function returning the transformation
4175	>	* for an element
4176	>	* @param basis the identity (initial default value) for the reduction
4177	>	* @param reducer a commutative associative combining function
4178	>	* @return the result of accumulating the given transformation
4179	>	* of all values
4180	>	* @since 1.8
4181		*/
4182	<	public Set<K> keySet() {
4183	<	Set<K> ks = keySet;
4184	<	return (ks != null) ? ks : (keySet = new KeySet());
4182	>	public int reduceValuesToInt(long parallelismThreshold,
4183	>	ToIntFunction<? super V> transformer,
4184	>	int basis,
4185	>	IntBinaryOperator reducer) {
4186	>	if (transformer == null || reducer == null)
4187	>	throw new NullPointerException();
4188	>	return new MapReduceValuesToIntTask<K,V>
4189	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4190	>	null, transformer, basis, reducer).invoke();
4191		}
4192
4193	+	/**
4194	+	* Performs the given action for each entry.
4195	+	*
4196	+	* @param parallelismThreshold the (estimated) number of elements
4197	+	* needed for this operation to be executed in parallel
4198	+	* @param action the action
4199	+	* @since 1.8
4200	+	*/
4201	+	public void forEachEntry(long parallelismThreshold,
4202	+	Consumer<? super Map.Entry<K,V>> action) {
4203	+	if (action == null) throw new NullPointerException();
4204	+	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4205	+	action).invoke();
4206	+	}
4207
4208		/**
4209	<	* Returns a collection view of the values contained in this map.  The
4210	<	* collection is backed by the map, so changes to the map are reflected in
960	<	* the collection, and vice-versa.  The collection supports element
961	<	* removal, which removes the corresponding mapping from this map, via the
962	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
963	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
964	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
965	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
966	<	* will never throw {@link java.util.ConcurrentModificationException},
967	<	* and guarantees to traverse elements as they existed upon
968	<	* construction of the iterator, and may (but is not guaranteed to)
969	<	* reflect any modifications subsequent to construction.
4209	>	* Performs the given action for each non-null transformation
4210	>	* of each entry.
4211		*
4212	<	* @return a collection view of the values contained in this map.
4212	>	* @param parallelismThreshold the (estimated) number of elements
4213	>	* needed for this operation to be executed in parallel
4214	>	* @param transformer a function returning the transformation
4215	>	* for an element, or null if there is no transformation (in
4216	>	* which case the action is not applied)
4217	>	* @param action the action
4218	>	* @param <U> the return type of the transformer
4219	>	* @since 1.8
4220		*/
4221	<	public Collection<V> values() {
4222	<	Collection<V> vs = values;
4223	<	return (vs != null) ? vs : (values = new Values());
4221	>	public <U> void forEachEntry(long parallelismThreshold,
4222	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4223	>	Consumer<? super U> action) {
4224	>	if (transformer == null || action == null)
4225	>	throw new NullPointerException();
4226	>	new ForEachTransformedEntryTask<K,V,U>
4227	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4228	>	transformer, action).invoke();
4229		}
4230
4231	+	/**
4232	+	* Returns a non-null result from applying the given search
4233	+	* function on each entry, or null if none.  Upon success,
4234	+	* further element processing is suppressed and the results of
4235	+	* any other parallel invocations of the search function are
4236	+	* ignored.
4237	+	*
4238	+	* @param parallelismThreshold the (estimated) number of elements
4239	+	* needed for this operation to be executed in parallel
4240	+	* @param searchFunction a function returning a non-null
4241	+	* result on success, else null
4242	+	* @param <U> the return type of the search function
4243	+	* @return a non-null result from applying the given search
4244	+	* function on each entry, or null if none
4245	+	* @since 1.8
4246	+	*/
4247	+	public <U> U searchEntries(long parallelismThreshold,
4248	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4249	+	if (searchFunction == null) throw new NullPointerException();
4250	+	return new SearchEntriesTask<K,V,U>
4251	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4252	+	searchFunction, new AtomicReference<U>()).invoke();
4253	+	}
4254
4255		/**
4256	<	* Returns a collection view of the mappings contained in this map.  Each
4257	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
982	<	* collection is backed by the map, so changes to the map are reflected in
983	<	* the collection, and vice-versa.  The collection supports element
984	<	* removal, which removes the corresponding mapping from the map, via the
985	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
986	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
987	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
988	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
989	<	* will never throw {@link java.util.ConcurrentModificationException},
990	<	* and guarantees to traverse elements as they existed upon
991	<	* construction of the iterator, and may (but is not guaranteed to)
992	<	* reflect any modifications subsequent to construction.
4256	>	* Returns the result of accumulating all entries using the
4257	>	* given reducer to combine values, or null if none.
4258		*
4259	<	* @return a collection view of the mappings contained in this map.
4259	>	* @param parallelismThreshold the (estimated) number of elements
4260	>	* needed for this operation to be executed in parallel
4261	>	* @param reducer a commutative associative combining function
4262	>	* @return the result of accumulating all entries
4263	>	* @since 1.8
4264		*/
4265	<	public Set<Map.Entry<K,V>> entrySet() {
4266	<	Set<Map.Entry<K,V>> es = entrySet;
4267	<	return (es != null) ? es : (entrySet = (Set<Map.Entry<K,V>>) (Set) new EntrySet());
4265	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4266	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4267	>	if (reducer == null) throw new NullPointerException();
4268	>	return new ReduceEntriesTask<K,V>
4269	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4270	>	null, reducer).invoke();
4271		}
4272
4273	+	/**
4274	+	* Returns the result of accumulating the given transformation
4275	+	* of all entries using the given reducer to combine values,
4276	+	* or null if none.
4277	+	*
4278	+	* @param parallelismThreshold the (estimated) number of elements
4279	+	* needed for this operation to be executed in parallel
4280	+	* @param transformer a function returning the transformation
4281	+	* for an element, or null if there is no transformation (in
4282	+	* which case it is not combined)
4283	+	* @param reducer a commutative associative combining function
4284	+	* @param <U> the return type of the transformer
4285	+	* @return the result of accumulating the given transformation
4286	+	* of all entries
4287	+	* @since 1.8
4288	+	*/
4289	+	public <U> U reduceEntries(long parallelismThreshold,
4290	+	Function<Map.Entry<K,V>, ? extends U> transformer,
4291	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4292	+	if (transformer == null || reducer == null)
4293	+	throw new NullPointerException();
4294	+	return new MapReduceEntriesTask<K,V,U>
4295	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4296	+	null, transformer, reducer).invoke();
4297	+	}
4298
4299		/**
4300	<	* Returns an enumeration of the keys in this table.
4300	>	* Returns the result of accumulating the given transformation
4301	>	* of all entries using the given reducer to combine values,
4302	>	* and the given basis as an identity value.
4303		*
4304	<	* @return  an enumeration of the keys in this table.
4305	<	* @see     #keySet
4304	>	* @param parallelismThreshold the (estimated) number of elements
4305	>	* needed for this operation to be executed in parallel
4306	>	* @param transformer a function returning the transformation
4307	>	* for an element
4308	>	* @param basis the identity (initial default value) for the reduction
4309	>	* @param reducer a commutative associative combining function
4310	>	* @return the result of accumulating the given transformation
4311	>	* of all entries
4312	>	* @since 1.8
4313		*/
4314	<	public Enumeration<K> keys() {
4315	<	return new KeyIterator();
4314	>	public double reduceEntriesToDouble(long parallelismThreshold,
4315	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4316	>	double basis,
4317	>	DoubleBinaryOperator reducer) {
4318	>	if (transformer == null || reducer == null)
4319	>	throw new NullPointerException();
4320	>	return new MapReduceEntriesToDoubleTask<K,V>
4321	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4322	>	null, transformer, basis, reducer).invoke();
4323		}
4324
4325		/**
4326	<	* Returns an enumeration of the values in this table.
4327	<	* Use the Enumeration methods on the returned object to fetch the elements
4328	<	* sequentially.
4326	>	* Returns the result of accumulating the given transformation
4327	>	* of all entries using the given reducer to combine values,
4328	>	* and the given basis as an identity value.
4329		*
4330	<	* @return  an enumeration of the values in this table.
4331	<	* @see     #values
4330	>	* @param parallelismThreshold the (estimated) number of elements
4331	>	* needed for this operation to be executed in parallel
4332	>	* @param transformer a function returning the transformation
4333	>	* for an element
4334	>	* @param basis the identity (initial default value) for the reduction
4335	>	* @param reducer a commutative associative combining function
4336	>	* @return the result of accumulating the given transformation
4337	>	* of all entries
4338	>	* @since 1.8
4339		*/
4340	<	public Enumeration<V> elements() {
4341	<	return new ValueIterator();
4340	>	public long reduceEntriesToLong(long parallelismThreshold,
4341	>	ToLongFunction<Map.Entry<K,V>> transformer,
4342	>	long basis,
4343	>	LongBinaryOperator reducer) {
4344	>	if (transformer == null || reducer == null)
4345	>	throw new NullPointerException();
4346	>	return new MapReduceEntriesToLongTask<K,V>
4347	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4348	>	null, transformer, basis, reducer).invoke();
4349	>	}
4350	>
4351	>	/**
4352	>	* Returns the result of accumulating the given transformation
4353	>	* of all entries using the given reducer to combine values,
4354	>	* and the given basis as an identity value.
4355	>	*
4356	>	* @param parallelismThreshold the (estimated) number of elements
4357	>	* needed for this operation to be executed in parallel
4358	>	* @param transformer a function returning the transformation
4359	>	* for an element
4360	>	* @param basis the identity (initial default value) for the reduction
4361	>	* @param reducer a commutative associative combining function
4362	>	* @return the result of accumulating the given transformation
4363	>	* of all entries
4364	>	* @since 1.8
4365	>	*/
4366	>	public int reduceEntriesToInt(long parallelismThreshold,
4367	>	ToIntFunction<Map.Entry<K,V>> transformer,
4368	>	int basis,
4369	>	IntBinaryOperator reducer) {
4370	>	if (transformer == null || reducer == null)
4371	>	throw new NullPointerException();
4372	>	return new MapReduceEntriesToIntTask<K,V>
4373	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4374	>	null, transformer, basis, reducer).invoke();
4375		}
4376
1024	–	/* ---------------- Iterator Support -------------- */
4377
4378	<	private abstract class HashIterator {
1027	<	private int nextSegmentIndex;
1028	<	private int nextTableIndex;
1029	<	private HashEntry[] currentTable;
1030	<	private HashEntry<K, V> nextEntry;
1031	<	HashEntry<K, V> lastReturned;
4378	>	/* ----------------Views -------------- */
4379
4380	<	private HashIterator() {
4381	<	nextSegmentIndex = segments.length - 1;
4382	<	nextTableIndex = -1;
4383	<	advance();
4380	>	/**
4381	>	* Base class for views.
4382	>	*/
4383	>	abstract static class CollectionView<K,V,E>
4384	>	implements Collection<E>, java.io.Serializable {
4385	>	private static final long serialVersionUID = 7249069246763182397L;
4386	>	final ConcurrentHashMap<K,V> map;
4387	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4388	>
4389	>	/**
4390	>	* Returns the map backing this view.
4391	>	*
4392	>	* @return the map backing this view
4393	>	*/
4394	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4395	>
4396	>	/**
4397	>	* Removes all of the elements from this view, by removing all
4398	>	* the mappings from the map backing this view.
4399	>	*/
4400	>	public final void clear()      { map.clear(); }
4401	>	public final int size()        { return map.size(); }
4402	>	public final boolean isEmpty() { return map.isEmpty(); }
4403	>
4404	>	// implementations below rely on concrete classes supplying these
4405	>	// abstract methods
4406	>	/**
4407	>	* Returns an iterator over the elements in this collection.
4408	>	*
4409	>	* <p>The returned iterator is
4410	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4411	>	*
4412	>	* @return an iterator over the elements in this collection
4413	>	*/
4414	>	public abstract Iterator<E> iterator();
4415	>	public abstract boolean contains(Object o);
4416	>	public abstract boolean remove(Object o);
4417	>
4418	>	private static final String OOME_MSG = "Required array size too large";
4419	>
4420	>	public final Object[] toArray() {
4421	>	long sz = map.mappingCount();
4422	>	if (sz > MAX_ARRAY_SIZE)
4423	>	throw new OutOfMemoryError(OOME_MSG);
4424	>	int n = (int)sz;
4425	>	Object[] r = new Object[n];
4426	>	int i = 0;
4427	>	for (E e : this) {
4428	>	if (i == n) {
4429	>	if (n >= MAX_ARRAY_SIZE)
4430	>	throw new OutOfMemoryError(OOME_MSG);
4431	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4432	>	n = MAX_ARRAY_SIZE;
4433	>	else
4434	>	n += (n >>> 1) + 1;
4435	>	r = Arrays.copyOf(r, n);
4436	>	}
4437	>	r[i++] = e;
4438	>	}
4439	>	return (i == n) ? r : Arrays.copyOf(r, i);
4440		}
4441
4442	<	public boolean hasMoreElements() { return hasNext(); }
4442	>	@SuppressWarnings("unchecked")
4443	>	public final <T> T[] toArray(T[] a) {
4444	>	long sz = map.mappingCount();
4445	>	if (sz > MAX_ARRAY_SIZE)
4446	>	throw new OutOfMemoryError(OOME_MSG);
4447	>	int m = (int)sz;
4448	>	T[] r = (a.length >= m) ? a :
4449	>	(T[])java.lang.reflect.Array
4450	>	.newInstance(a.getClass().getComponentType(), m);
4451	>	int n = r.length;
4452	>	int i = 0;
4453	>	for (E e : this) {
4454	>	if (i == n) {
4455	>	if (n >= MAX_ARRAY_SIZE)
4456	>	throw new OutOfMemoryError(OOME_MSG);
4457	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4458	>	n = MAX_ARRAY_SIZE;
4459	>	else
4460	>	n += (n >>> 1) + 1;
4461	>	r = Arrays.copyOf(r, n);
4462	>	}
4463	>	r[i++] = (T)e;
4464	>	}
4465	>	if (a == r && i < n) {
4466	>	r[i] = null; // null-terminate
4467	>	return r;
4468	>	}
4469	>	return (i == n) ? r : Arrays.copyOf(r, i);
4470	>	}
4471
4472	<	private void advance() {
4473	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
4474	<	return;
4472	>	/**
4473	>	* Returns a string representation of this collection.
4474	>	* The string representation consists of the string representations
4475	>	* of the collection's elements in the order they are returned by
4476	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4477	>	* Adjacent elements are separated by the characters {@code ", "}
4478	>	* (comma and space).  Elements are converted to strings as by
4479	>	* {@link String#valueOf(Object)}.
4480	>	*
4481	>	* @return a string representation of this collection
4482	>	*/
4483	>	public final String toString() {
4484	>	StringBuilder sb = new StringBuilder();
4485	>	sb.append('[');
4486	>	Iterator<E> it = iterator();
4487	>	if (it.hasNext()) {
4488	>	for (;;) {
4489	>	Object e = it.next();
4490	>	sb.append(e == this ? "(this Collection)" : e);
4491	>	if (!it.hasNext())
4492	>	break;
4493	>	sb.append(',').append(' ');
4494	>	}
4495	>	}
4496	>	return sb.append(']').toString();
4497	>	}
4498
4499	<	while (nextTableIndex >= 0) {
4500	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[nextTableIndex--]) != null)
4501	<	return;
4499	>	public final boolean containsAll(Collection<?> c) {
4500	>	if (c != this) {
4501	>	for (Object e : c) {
4502	>	if (e == null || !contains(e))
4503	>	return false;
4504	>	}
4505		}
4506	+	return true;
4507	+	}
4508
4509	<	while (nextSegmentIndex >= 0) {
4510	<	Segment<K,V> seg = (Segment<K,V>)segments[nextSegmentIndex--];
4511	<	if (seg.count != 0) {
4512	<	currentTable = seg.table;
4513	<	for (int j = currentTable.length - 1; j >= 0; --j) {
4514	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[j]) != null) {
4515	<	nextTableIndex = j - 1;
4516	<	return;
4517	<	}
4509	>	public boolean removeAll(Collection<?> c) {
4510	>	if (c == null) throw new NullPointerException();
4511	>	boolean modified = false;
4512	>	// Use (c instanceof Set) as a hint that lookup in c is as
4513	>	// efficient as this view
4514	>	Node<K,V>[] t;
4515	>	if ((t = map.table) == null) {
4516	>	return false;
4517	>	} else if (c instanceof Set<?> && c.size() > t.length) {
4518	>	for (Iterator<?> it = iterator(); it.hasNext(); ) {
4519	>	if (c.contains(it.next())) {
4520	>	it.remove();
4521	>	modified = true;
4522		}
4523		}
4524	+	} else {
4525	+	for (Object e : c)
4526	+	modified |= remove(e);
4527		}
4528	+	return modified;
4529		}
4530
4531	<	public boolean hasNext() { return nextEntry != null; }
4531	>	public final boolean retainAll(Collection<?> c) {
4532	>	if (c == null) throw new NullPointerException();
4533	>	boolean modified = false;
4534	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4535	>	if (!c.contains(it.next())) {
4536	>	it.remove();
4537	>	modified = true;
4538	>	}
4539	>	}
4540	>	return modified;
4541	>	}
4542
4543	<	HashEntry<K,V> nextEntry() {
4544	<	if (nextEntry == null)
4545	<	throw new NoSuchElementException();
4546	<	lastReturned = nextEntry;
4547	<	advance();
4548	<	return lastReturned;
4543	>	}
4544	>
4545	>	/**
4546	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4547	>	* which additions may optionally be enabled by mapping to a
4548	>	* common value.  This class cannot be directly instantiated.
4549	>	* See {@link #keySet() keySet()},
4550	>	* {@link #keySet(Object) keySet(V)},
4551	>	* {@link #newKeySet() newKeySet()},
4552	>	* {@link #newKeySet(int) newKeySet(int)}.
4553	>	*
4554	>	* @since 1.8
4555	>	*/
4556	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4557	>	implements Set<K>, java.io.Serializable {
4558	>	private static final long serialVersionUID = 7249069246763182397L;
4559	>	private final V value;
4560	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4561	>	super(map);
4562	>	this.value = value;
4563		}
4564
4565	<	public void remove() {
4566	<	if (lastReturned == null)
4567	<	throw new IllegalStateException();
4568	<	ConcurrentHashMap.this.remove(lastReturned.key);
4569	<	lastReturned = null;
4565	>	/**
4566	>	* Returns the default mapped value for additions,
4567	>	* or {@code null} if additions are not supported.
4568	>	*
4569	>	* @return the default mapped value for additions, or {@code null}
4570	>	* if not supported
4571	>	*/
4572	>	public V getMappedValue() { return value; }
4573	>
4574	>	/**
4575	>	* {@inheritDoc}
4576	>	* @throws NullPointerException if the specified key is null
4577	>	*/
4578	>	public boolean contains(Object o) { return map.containsKey(o); }
4579	>
4580	>	/**
4581	>	* Removes the key from this map view, by removing the key (and its
4582	>	* corresponding value) from the backing map.  This method does
4583	>	* nothing if the key is not in the map.
4584	>	*
4585	>	* @param  o the key to be removed from the backing map
4586	>	* @return {@code true} if the backing map contained the specified key
4587	>	* @throws NullPointerException if the specified key is null
4588	>	*/
4589	>	public boolean remove(Object o) { return map.remove(o) != null; }
4590	>
4591	>	/**
4592	>	* @return an iterator over the keys of the backing map
4593	>	*/
4594	>	public Iterator<K> iterator() {
4595	>	Node<K,V>[] t;
4596	>	ConcurrentHashMap<K,V> m = map;
4597	>	int f = (t = m.table) == null ? 0 : t.length;
4598	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4599		}
1080	–	}
4600
4601	<	private class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
4602	<	public K next() { return super.nextEntry().key; }
4603	<	public K nextElement() { return super.nextEntry().key; }
4604	<	}
4601	>	/**
4602	>	* Adds the specified key to this set view by mapping the key to
4603	>	* the default mapped value in the backing map, if defined.
4604	>	*
4605	>	* @param e key to be added
4606	>	* @return {@code true} if this set changed as a result of the call
4607	>	* @throws NullPointerException if the specified key is null
4608	>	* @throws UnsupportedOperationException if no default mapped value
4609	>	* for additions was provided
4610	>	*/
4611	>	public boolean add(K e) {
4612	>	V v;
4613	>	if ((v = value) == null)
4614	>	throw new UnsupportedOperationException();
4615	>	return map.putVal(e, v, true) == null;
4616	>	}
4617
4618	<	private class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
4619	<	public V next() { return super.nextEntry().value; }
4620	<	public V nextElement() { return super.nextEntry().value; }
4618	>	/**
4619	>	* Adds all of the elements in the specified collection to this set,
4620	>	* as if by calling {@link #add} on each one.
4621	>	*
4622	>	* @param c the elements to be inserted into this set
4623	>	* @return {@code true} if this set changed as a result of the call
4624	>	* @throws NullPointerException if the collection or any of its
4625	>	* elements are {@code null}
4626	>	* @throws UnsupportedOperationException if no default mapped value
4627	>	* for additions was provided
4628	>	*/
4629	>	public boolean addAll(Collection<? extends K> c) {
4630	>	boolean added = false;
4631	>	V v;
4632	>	if ((v = value) == null)
4633	>	throw new UnsupportedOperationException();
4634	>	for (K e : c) {
4635	>	if (map.putVal(e, v, true) == null)
4636	>	added = true;
4637	>	}
4638	>	return added;
4639	>	}
4640	>
4641	>	public int hashCode() {
4642	>	int h = 0;
4643	>	for (K e : this)
4644	>	h += e.hashCode();
4645	>	return h;
4646	>	}
4647	>
4648	>	public boolean equals(Object o) {
4649	>	Set<?> c;
4650	>	return ((o instanceof Set) &&
4651	>	((c = (Set<?>)o) == this ||
4652	>	(containsAll(c) && c.containsAll(this))));
4653	>	}
4654	>
4655	>	public Spliterator<K> spliterator() {
4656	>	Node<K,V>[] t;
4657	>	ConcurrentHashMap<K,V> m = map;
4658	>	long n = m.sumCount();
4659	>	int f = (t = m.table) == null ? 0 : t.length;
4660	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4661	>	}
4662	>
4663	>	public void forEach(Consumer<? super K> action) {
4664	>	if (action == null) throw new NullPointerException();
4665	>	Node<K,V>[] t;
4666	>	if ((t = map.table) != null) {
4667	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4668	>	for (Node<K,V> p; (p = it.advance()) != null; )
4669	>	action.accept(p.key);
4670	>	}
4671	>	}
4672		}
4673
4674	<
4674	>	/**
4675	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4676	>	* values, in which additions are disabled. This class cannot be
4677	>	* directly instantiated. See {@link #values()}.
4678	>	*/
4679	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4680	>	implements Collection<V>, java.io.Serializable {
4681	>	private static final long serialVersionUID = 2249069246763182397L;
4682	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4683	>	public final boolean contains(Object o) {
4684	>	return map.containsValue(o);
4685	>	}
4686	>
4687	>	public final boolean remove(Object o) {
4688	>	if (o != null) {
4689	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4690	>	if (o.equals(it.next())) {
4691	>	it.remove();
4692	>	return true;
4693	>	}
4694	>	}
4695	>	}
4696	>	return false;
4697	>	}
4698	>
4699	>	public final Iterator<V> iterator() {
4700	>	ConcurrentHashMap<K,V> m = map;
4701	>	Node<K,V>[] t;
4702	>	int f = (t = m.table) == null ? 0 : t.length;
4703	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4704	>	}
4705	>
4706	>	public final boolean add(V e) {
4707	>	throw new UnsupportedOperationException();
4708	>	}
4709	>	public final boolean addAll(Collection<? extends V> c) {
4710	>	throw new UnsupportedOperationException();
4711	>	}
4712	>
4713	>	@Override public boolean removeAll(Collection<?> c) {
4714	>	if (c == null) throw new NullPointerException();
4715	>	boolean modified = false;
4716	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4717	>	if (c.contains(it.next())) {
4718	>	it.remove();
4719	>	modified = true;
4720	>	}
4721	>	}
4722	>	return modified;
4723	>	}
4724	>
4725	>	public boolean removeIf(Predicate<? super V> filter) {
4726	>	return map.removeValueIf(filter);
4727	>	}
4728	>
4729	>	public Spliterator<V> spliterator() {
4730	>	Node<K,V>[] t;
4731	>	ConcurrentHashMap<K,V> m = map;
4732	>	long n = m.sumCount();
4733	>	int f = (t = m.table) == null ? 0 : t.length;
4734	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4735	>	}
4736	>
4737	>	public void forEach(Consumer<? super V> action) {
4738	>	if (action == null) throw new NullPointerException();
4739	>	Node<K,V>[] t;
4740	>	if ((t = map.table) != null) {
4741	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4742	>	for (Node<K,V> p; (p = it.advance()) != null; )
4743	>	action.accept(p.val);
4744	>	}
4745	>	}
4746	>	}
4747
4748		/**
4749	<	* Exported Entry objects must write-through changes in setValue,
4750	<	* even if the nodes have been cloned. So we cannot return
4751	<	* internal HashEntry objects. Instead, the iterator itself acts
1098	<	* as a forwarding pseudo-entry.
4749	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4750	>	* entries.  This class cannot be directly instantiated. See
4751	>	* {@link #entrySet()}.
4752		*/
4753	<	private class EntryIterator extends HashIterator implements Map.Entry<K,V>, Iterator<Entry<K,V>> {
4754	<	public Map.Entry<K,V> next() {
4755	<	nextEntry();
4756	<	return this;
4753	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4754	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4755	>	private static final long serialVersionUID = 2249069246763182397L;
4756	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4757	>
4758	>	public boolean contains(Object o) {
4759	>	Object k, v, r; Map.Entry<?,?> e;
4760	>	return ((o instanceof Map.Entry) &&
4761	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4762	>	(r = map.get(k)) != null &&
4763	>	(v = e.getValue()) != null &&
4764	>	(v == r || v.equals(r)));
4765		}
4766
4767	<	public K getKey() {
4768	<	if (lastReturned == null)
4769	<	throw new IllegalStateException("Entry was removed");
4770	<	return lastReturned.key;
4767	>	public boolean remove(Object o) {
4768	>	Object k, v; Map.Entry<?,?> e;
4769	>	return ((o instanceof Map.Entry) &&
4770	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4771	>	(v = e.getValue()) != null &&
4772	>	map.remove(k, v));
4773		}
4774
4775	<	public V getValue() {
4776	<	if (lastReturned == null)
4777	<	throw new IllegalStateException("Entry was removed");
4778	<	return ConcurrentHashMap.this.get(lastReturned.key);
4775	>	/**
4776	>	* @return an iterator over the entries of the backing map
4777	>	*/
4778	>	public Iterator<Map.Entry<K,V>> iterator() {
4779	>	ConcurrentHashMap<K,V> m = map;
4780	>	Node<K,V>[] t;
4781	>	int f = (t = m.table) == null ? 0 : t.length;
4782	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4783		}
4784
4785	<	public V setValue(V value) {
4786	<	if (lastReturned == null)
1120	<	throw new IllegalStateException("Entry was removed");
1121	<	return ConcurrentHashMap.this.put(lastReturned.key, value);
4785	>	public boolean add(Entry<K,V> e) {
4786	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4787		}
4788
4789	<	public boolean equals(Object o) {
4790	<	if (!(o instanceof Map.Entry))
4791	<	return false;
4792	<	Map.Entry e = (Map.Entry)o;
4793	<	return eq(getKey(), e.getKey()) && eq(getValue(), e.getValue());
4794	<	}
4789	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4790	>	boolean added = false;
4791	>	for (Entry<K,V> e : c) {
4792	>	if (add(e))
4793	>	added = true;
4794	>	}
4795	>	return added;
4796	>	}
4797
4798	<	public int hashCode() {
4799	<	Object k = getKey();
1133	<	Object v = getValue();
1134	<	return ((k == null) ? 0 : k.hashCode()) ^
1135	<	((v == null) ? 0 : v.hashCode());
4798	>	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4799	>	return map.removeEntryIf(filter);
4800		}
4801
4802	<	public String toString() {
4803	<	// If not acting as entry, just use default toString.
4804	<	if (lastReturned == null)
4805	<	return super.toString();
4806	<	else
4807	<	return getKey() + "=" + getValue();
4802	>	public final int hashCode() {
4803	>	int h = 0;
4804	>	Node<K,V>[] t;
4805	>	if ((t = map.table) != null) {
4806	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4807	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4808	>	h += p.hashCode();
4809	>	}
4810	>	}
4811	>	return h;
4812		}
4813
4814	<	private boolean eq(Object o1, Object o2) {
4815	<	return (o1 == null ? o2 == null : o1.equals(o2));
4814	>	public final boolean equals(Object o) {
4815	>	Set<?> c;
4816	>	return ((o instanceof Set) &&
4817	>	((c = (Set<?>)o) == this ||
4818	>	(containsAll(c) && c.containsAll(this))));
4819	>	}
4820	>
4821	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4822	>	Node<K,V>[] t;
4823	>	ConcurrentHashMap<K,V> m = map;
4824	>	long n = m.sumCount();
4825	>	int f = (t = m.table) == null ? 0 : t.length;
4826	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4827	>	}
4828	>
4829	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4830	>	if (action == null) throw new NullPointerException();
4831	>	Node<K,V>[] t;
4832	>	if ((t = map.table) != null) {
4833	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4834	>	for (Node<K,V> p; (p = it.advance()) != null; )
4835	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4836	>	}
4837		}
4838
4839		}
4840
4841	<	private class KeySet extends AbstractSet<K> {
4842	<	public Iterator<K> iterator() {
4843	<	return new KeyIterator();
4841	>	// -------------------------------------------------------
4842	>
4843	>	/**
4844	>	* Base class for bulk tasks. Repeats some fields and code from
4845	>	* class Traverser, because we need to subclass CountedCompleter.
4846	>	*/
4847	>	@SuppressWarnings("serial")
4848	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4849	>	Node<K,V>[] tab;        // same as Traverser
4850	>	Node<K,V> next;
4851	>	TableStack<K,V> stack, spare;
4852	>	int index;
4853	>	int baseIndex;
4854	>	int baseLimit;
4855	>	final int baseSize;
4856	>	int batch;              // split control
4857	>
4858	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4859	>	super(par);
4860	>	this.batch = b;
4861	>	this.index = this.baseIndex = i;
4862	>	if ((this.tab = t) == null)
4863	>	this.baseSize = this.baseLimit = 0;
4864	>	else if (par == null)
4865	>	this.baseSize = this.baseLimit = t.length;
4866	>	else {
4867	>	this.baseLimit = f;
4868	>	this.baseSize = par.baseSize;
4869	>	}
4870		}
4871	<	public int size() {
4872	<	return ConcurrentHashMap.this.size();
4871	>
4872	>	/**
4873	>	* Same as Traverser version.
4874	>	*/
4875	>	final Node<K,V> advance() {
4876	>	Node<K,V> e;
4877	>	if ((e = next) != null)
4878	>	e = e.next;
4879	>	for (;;) {
4880	>	Node<K,V>[] t; int i, n;
4881	>	if (e != null)
4882	>	return next = e;
4883	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4884	>	(n = t.length) <= (i = index) || i < 0)
4885	>	return next = null;
4886	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4887	>	if (e instanceof ForwardingNode) {
4888	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4889	>	e = null;
4890	>	pushState(t, i, n);
4891	>	continue;
4892	>	}
4893	>	else if (e instanceof TreeBin)
4894	>	e = ((TreeBin<K,V>)e).first;
4895	>	else
4896	>	e = null;
4897	>	}
4898	>	if (stack != null)
4899	>	recoverState(n);
4900	>	else if ((index = i + baseSize) >= n)
4901	>	index = ++baseIndex;
4902	>	}
4903		}
4904	<	public boolean contains(Object o) {
4905	<	return ConcurrentHashMap.this.containsKey(o);
4904	>
4905	>	private void pushState(Node<K,V>[] t, int i, int n) {
4906	>	TableStack<K,V> s = spare;
4907	>	if (s != null)
4908	>	spare = s.next;
4909	>	else
4910	>	s = new TableStack<K,V>();
4911	>	s.tab = t;
4912	>	s.length = n;
4913	>	s.index = i;
4914	>	s.next = stack;
4915	>	stack = s;
4916	>	}
4917	>
4918	>	private void recoverState(int n) {
4919	>	TableStack<K,V> s; int len;
4920	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4921	>	n = len;
4922	>	index = s.index;
4923	>	tab = s.tab;
4924	>	s.tab = null;
4925	>	TableStack<K,V> next = s.next;
4926	>	s.next = spare; // save for reuse
4927	>	stack = next;
4928	>	spare = s;
4929	>	}
4930	>	if (s == null && (index += baseSize) >= n)
4931	>	index = ++baseIndex;
4932		}
4933	<	public boolean remove(Object o) {
4934	<	return ConcurrentHashMap.this.remove(o) != null;
4933	>	}
4934	>
4935	>	/*
4936	>	* Task classes. Coded in a regular but ugly format/style to
4937	>	* simplify checks that each variant differs in the right way from
4938	>	* others. The null screenings exist because compilers cannot tell
4939	>	* that we've already null-checked task arguments, so we force
4940	>	* simplest hoisted bypass to help avoid convoluted traps.
4941	>	*/
4942	>	@SuppressWarnings("serial")
4943	>	static final class ForEachKeyTask<K,V>
4944	>	extends BulkTask<K,V,Void> {
4945	>	final Consumer<? super K> action;
4946	>	ForEachKeyTask
4947	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4948	>	Consumer<? super K> action) {
4949	>	super(p, b, i, f, t);
4950	>	this.action = action;
4951	>	}
4952	>	public final void compute() {
4953	>	final Consumer<? super K> action;
4954	>	if ((action = this.action) != null) {
4955	>	for (int i = baseIndex, f, h; batch > 0 &&
4956	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4957	>	addToPendingCount(1);
4958	>	new ForEachKeyTask<K,V>
4959	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4960	>	action).fork();
4961	>	}
4962	>	for (Node<K,V> p; (p = advance()) != null;)
4963	>	action.accept(p.key);
4964	>	propagateCompletion();
4965	>	}
4966		}
4967	<	public void clear() {
4968	<	ConcurrentHashMap.this.clear();
4967	>	}
4968	>
4969	>	@SuppressWarnings("serial")
4970	>	static final class ForEachValueTask<K,V>
4971	>	extends BulkTask<K,V,Void> {
4972	>	final Consumer<? super V> action;
4973	>	ForEachValueTask
4974	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4975	>	Consumer<? super V> action) {
4976	>	super(p, b, i, f, t);
4977	>	this.action = action;
4978	>	}
4979	>	public final void compute() {
4980	>	final Consumer<? super V> action;
4981	>	if ((action = this.action) != null) {
4982	>	for (int i = baseIndex, f, h; batch > 0 &&
4983	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4984	>	addToPendingCount(1);
4985	>	new ForEachValueTask<K,V>
4986	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4987	>	action).fork();
4988	>	}
4989	>	for (Node<K,V> p; (p = advance()) != null;)
4990	>	action.accept(p.val);
4991	>	propagateCompletion();
4992	>	}
4993		}
4994		}
4995
4996	<	private class Values extends AbstractCollection<V> {
4997	<	public Iterator<V> iterator() {
4998	<	return new ValueIterator();
4996	>	@SuppressWarnings("serial")
4997	>	static final class ForEachEntryTask<K,V>
4998	>	extends BulkTask<K,V,Void> {
4999	>	final Consumer<? super Entry<K,V>> action;
5000	>	ForEachEntryTask
5001	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5002	>	Consumer<? super Entry<K,V>> action) {
5003	>	super(p, b, i, f, t);
5004	>	this.action = action;
5005	>	}
5006	>	public final void compute() {
5007	>	final Consumer<? super Entry<K,V>> action;
5008	>	if ((action = this.action) != null) {
5009	>	for (int i = baseIndex, f, h; batch > 0 &&
5010	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5011	>	addToPendingCount(1);
5012	>	new ForEachEntryTask<K,V>
5013	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5014	>	action).fork();
5015	>	}
5016	>	for (Node<K,V> p; (p = advance()) != null; )
5017	>	action.accept(p);
5018	>	propagateCompletion();
5019	>	}
5020		}
5021	<	public int size() {
5022	<	return ConcurrentHashMap.this.size();
5021	>	}
5022	>
5023	>	@SuppressWarnings("serial")
5024	>	static final class ForEachMappingTask<K,V>
5025	>	extends BulkTask<K,V,Void> {
5026	>	final BiConsumer<? super K, ? super V> action;
5027	>	ForEachMappingTask
5028	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5029	>	BiConsumer<? super K,? super V> action) {
5030	>	super(p, b, i, f, t);
5031	>	this.action = action;
5032	>	}
5033	>	public final void compute() {
5034	>	final BiConsumer<? super K, ? super V> action;
5035	>	if ((action = this.action) != null) {
5036	>	for (int i = baseIndex, f, h; batch > 0 &&
5037	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5038	>	addToPendingCount(1);
5039	>	new ForEachMappingTask<K,V>
5040	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5041	>	action).fork();
5042	>	}
5043	>	for (Node<K,V> p; (p = advance()) != null; )
5044	>	action.accept(p.key, p.val);
5045	>	propagateCompletion();
5046	>	}
5047		}
5048	<	public boolean contains(Object o) {
5049	<	return ConcurrentHashMap.this.containsValue(o);
5048	>	}
5049	>
5050	>	@SuppressWarnings("serial")
5051	>	static final class ForEachTransformedKeyTask<K,V,U>
5052	>	extends BulkTask<K,V,Void> {
5053	>	final Function<? super K, ? extends U> transformer;
5054	>	final Consumer<? super U> action;
5055	>	ForEachTransformedKeyTask
5056	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5057	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5058	>	super(p, b, i, f, t);
5059	>	this.transformer = transformer; this.action = action;
5060	>	}
5061	>	public final void compute() {
5062	>	final Function<? super K, ? extends U> transformer;
5063	>	final Consumer<? super U> action;
5064	>	if ((transformer = this.transformer) != null &&
5065	>	(action = this.action) != null) {
5066	>	for (int i = baseIndex, f, h; batch > 0 &&
5067	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5068	>	addToPendingCount(1);
5069	>	new ForEachTransformedKeyTask<K,V,U>
5070	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5071	>	transformer, action).fork();
5072	>	}
5073	>	for (Node<K,V> p; (p = advance()) != null; ) {
5074	>	U u;
5075	>	if ((u = transformer.apply(p.key)) != null)
5076	>	action.accept(u);
5077	>	}
5078	>	propagateCompletion();
5079	>	}
5080		}
5081	<	public void clear() {
5082	<	ConcurrentHashMap.this.clear();
5081	>	}
5082	>
5083	>	@SuppressWarnings("serial")
5084	>	static final class ForEachTransformedValueTask<K,V,U>
5085	>	extends BulkTask<K,V,Void> {
5086	>	final Function<? super V, ? extends U> transformer;
5087	>	final Consumer<? super U> action;
5088	>	ForEachTransformedValueTask
5089	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5090	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5091	>	super(p, b, i, f, t);
5092	>	this.transformer = transformer; this.action = action;
5093	>	}
5094	>	public final void compute() {
5095	>	final Function<? super V, ? extends U> transformer;
5096	>	final Consumer<? super U> action;
5097	>	if ((transformer = this.transformer) != null &&
5098	>	(action = this.action) != null) {
5099	>	for (int i = baseIndex, f, h; batch > 0 &&
5100	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5101	>	addToPendingCount(1);
5102	>	new ForEachTransformedValueTask<K,V,U>
5103	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5104	>	transformer, action).fork();
5105	>	}
5106	>	for (Node<K,V> p; (p = advance()) != null; ) {
5107	>	U u;
5108	>	if ((u = transformer.apply(p.val)) != null)
5109	>	action.accept(u);
5110	>	}
5111	>	propagateCompletion();
5112	>	}
5113		}
5114		}
5115
5116	<	private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
5117	<	public Iterator<Map.Entry<K,V>> iterator() {
5118	<	return new EntryIterator();
5116	>	@SuppressWarnings("serial")
5117	>	static final class ForEachTransformedEntryTask<K,V,U>
5118	>	extends BulkTask<K,V,Void> {
5119	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5120	>	final Consumer<? super U> action;
5121	>	ForEachTransformedEntryTask
5122	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5123	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5124	>	super(p, b, i, f, t);
5125	>	this.transformer = transformer; this.action = action;
5126	>	}
5127	>	public final void compute() {
5128	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5129	>	final Consumer<? super U> action;
5130	>	if ((transformer = this.transformer) != null &&
5131	>	(action = this.action) != null) {
5132	>	for (int i = baseIndex, f, h; batch > 0 &&
5133	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5134	>	addToPendingCount(1);
5135	>	new ForEachTransformedEntryTask<K,V,U>
5136	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5137	>	transformer, action).fork();
5138	>	}
5139	>	for (Node<K,V> p; (p = advance()) != null; ) {
5140	>	U u;
5141	>	if ((u = transformer.apply(p)) != null)
5142	>	action.accept(u);
5143	>	}
5144	>	propagateCompletion();
5145	>	}
5146		}
5147	<	public boolean contains(Object o) {
5148	<	if (!(o instanceof Map.Entry))
5149	<	return false;
5150	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5151	<	V v = ConcurrentHashMap.this.get(e.getKey());
5152	<	return v != null && v.equals(e.getValue());
5147	>	}
5148	>
5149	>	@SuppressWarnings("serial")
5150	>	static final class ForEachTransformedMappingTask<K,V,U>
5151	>	extends BulkTask<K,V,Void> {
5152	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5153	>	final Consumer<? super U> action;
5154	>	ForEachTransformedMappingTask
5155	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5156	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5157	>	Consumer<? super U> action) {
5158	>	super(p, b, i, f, t);
5159	>	this.transformer = transformer; this.action = action;
5160	>	}
5161	>	public final void compute() {
5162	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5163	>	final Consumer<? super U> action;
5164	>	if ((transformer = this.transformer) != null &&
5165	>	(action = this.action) != null) {
5166	>	for (int i = baseIndex, f, h; batch > 0 &&
5167	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5168	>	addToPendingCount(1);
5169	>	new ForEachTransformedMappingTask<K,V,U>
5170	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5171	>	transformer, action).fork();
5172	>	}
5173	>	for (Node<K,V> p; (p = advance()) != null; ) {
5174	>	U u;
5175	>	if ((u = transformer.apply(p.key, p.val)) != null)
5176	>	action.accept(u);
5177	>	}
5178	>	propagateCompletion();
5179	>	}
5180		}
5181	<	public boolean remove(Object o) {
5182	<	if (!(o instanceof Map.Entry))
5183	<	return false;
5184	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5185	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
5181	>	}
5182	>
5183	>	@SuppressWarnings("serial")
5184	>	static final class SearchKeysTask<K,V,U>
5185	>	extends BulkTask<K,V,U> {
5186	>	final Function<? super K, ? extends U> searchFunction;
5187	>	final AtomicReference<U> result;
5188	>	SearchKeysTask
5189	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5190	>	Function<? super K, ? extends U> searchFunction,
5191	>	AtomicReference<U> result) {
5192	>	super(p, b, i, f, t);
5193	>	this.searchFunction = searchFunction; this.result = result;
5194	>	}
5195	>	public final U getRawResult() { return result.get(); }
5196	>	public final void compute() {
5197	>	final Function<? super K, ? extends U> searchFunction;
5198	>	final AtomicReference<U> result;
5199	>	if ((searchFunction = this.searchFunction) != null &&
5200	>	(result = this.result) != null) {
5201	>	for (int i = baseIndex, f, h; batch > 0 &&
5202	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5203	>	if (result.get() != null)
5204	>	return;
5205	>	addToPendingCount(1);
5206	>	new SearchKeysTask<K,V,U>
5207	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5208	>	searchFunction, result).fork();
5209	>	}
5210	>	while (result.get() == null) {
5211	>	U u;
5212	>	Node<K,V> p;
5213	>	if ((p = advance()) == null) {
5214	>	propagateCompletion();
5215	>	break;
5216	>	}
5217	>	if ((u = searchFunction.apply(p.key)) != null) {
5218	>	if (result.compareAndSet(null, u))
5219	>	quietlyCompleteRoot();
5220	>	break;
5221	>	}
5222	>	}
5223	>	}
5224		}
5225	<	public int size() {
5226	<	return ConcurrentHashMap.this.size();
5225	>	}
5226	>
5227	>	@SuppressWarnings("serial")
5228	>	static final class SearchValuesTask<K,V,U>
5229	>	extends BulkTask<K,V,U> {
5230	>	final Function<? super V, ? extends U> searchFunction;
5231	>	final AtomicReference<U> result;
5232	>	SearchValuesTask
5233	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5234	>	Function<? super V, ? extends U> searchFunction,
5235	>	AtomicReference<U> result) {
5236	>	super(p, b, i, f, t);
5237	>	this.searchFunction = searchFunction; this.result = result;
5238	>	}
5239	>	public final U getRawResult() { return result.get(); }
5240	>	public final void compute() {
5241	>	final Function<? super V, ? extends U> searchFunction;
5242	>	final AtomicReference<U> result;
5243	>	if ((searchFunction = this.searchFunction) != null &&
5244	>	(result = this.result) != null) {
5245	>	for (int i = baseIndex, f, h; batch > 0 &&
5246	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5247	>	if (result.get() != null)
5248	>	return;
5249	>	addToPendingCount(1);
5250	>	new SearchValuesTask<K,V,U>
5251	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5252	>	searchFunction, result).fork();
5253	>	}
5254	>	while (result.get() == null) {
5255	>	U u;
5256	>	Node<K,V> p;
5257	>	if ((p = advance()) == null) {
5258	>	propagateCompletion();
5259	>	break;
5260	>	}
5261	>	if ((u = searchFunction.apply(p.val)) != null) {
5262	>	if (result.compareAndSet(null, u))
5263	>	quietlyCompleteRoot();
5264	>	break;
5265	>	}
5266	>	}
5267	>	}
5268		}
5269	<	public void clear() {
5270	<	ConcurrentHashMap.this.clear();
5269	>	}
5270	>
5271	>	@SuppressWarnings("serial")
5272	>	static final class SearchEntriesTask<K,V,U>
5273	>	extends BulkTask<K,V,U> {
5274	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5275	>	final AtomicReference<U> result;
5276	>	SearchEntriesTask
5277	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5278	>	Function<Entry<K,V>, ? extends U> searchFunction,
5279	>	AtomicReference<U> result) {
5280	>	super(p, b, i, f, t);
5281	>	this.searchFunction = searchFunction; this.result = result;
5282	>	}
5283	>	public final U getRawResult() { return result.get(); }
5284	>	public final void compute() {
5285	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5286	>	final AtomicReference<U> result;
5287	>	if ((searchFunction = this.searchFunction) != null &&
5288	>	(result = this.result) != null) {
5289	>	for (int i = baseIndex, f, h; batch > 0 &&
5290	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5291	>	if (result.get() != null)
5292	>	return;
5293	>	addToPendingCount(1);
5294	>	new SearchEntriesTask<K,V,U>
5295	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5296	>	searchFunction, result).fork();
5297	>	}
5298	>	while (result.get() == null) {
5299	>	U u;
5300	>	Node<K,V> p;
5301	>	if ((p = advance()) == null) {
5302	>	propagateCompletion();
5303	>	break;
5304	>	}
5305	>	if ((u = searchFunction.apply(p)) != null) {
5306	>	if (result.compareAndSet(null, u))
5307	>	quietlyCompleteRoot();
5308	>	return;
5309	>	}
5310	>	}
5311	>	}
5312		}
5313	<	public Object[] toArray() {
5314	<	// Since we don't ordinarily have distinct Entry objects, we
5315	<	// must pack elements using exportable SimpleEntry
5316	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
5317	<	for (Iterator<Map.Entry<K,V>> i = iterator(); i.hasNext(); )
5318	<	c.add(new SimpleEntry<K,V>(i.next()));
5319	<	return c.toArray();
5313	>	}
5314	>
5315	>	@SuppressWarnings("serial")
5316	>	static final class SearchMappingsTask<K,V,U>
5317	>	extends BulkTask<K,V,U> {
5318	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5319	>	final AtomicReference<U> result;
5320	>	SearchMappingsTask
5321	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5322	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5323	>	AtomicReference<U> result) {
5324	>	super(p, b, i, f, t);
5325	>	this.searchFunction = searchFunction; this.result = result;
5326	>	}
5327	>	public final U getRawResult() { return result.get(); }
5328	>	public final void compute() {
5329	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5330	>	final AtomicReference<U> result;
5331	>	if ((searchFunction = this.searchFunction) != null &&
5332	>	(result = this.result) != null) {
5333	>	for (int i = baseIndex, f, h; batch > 0 &&
5334	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5335	>	if (result.get() != null)
5336	>	return;
5337	>	addToPendingCount(1);
5338	>	new SearchMappingsTask<K,V,U>
5339	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5340	>	searchFunction, result).fork();
5341	>	}
5342	>	while (result.get() == null) {
5343	>	U u;
5344	>	Node<K,V> p;
5345	>	if ((p = advance()) == null) {
5346	>	propagateCompletion();
5347	>	break;
5348	>	}
5349	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5350	>	if (result.compareAndSet(null, u))
5351	>	quietlyCompleteRoot();
5352	>	break;
5353	>	}
5354	>	}
5355	>	}
5356	>	}
5357	>	}
5358	>
5359	>	@SuppressWarnings("serial")
5360	>	static final class ReduceKeysTask<K,V>
5361	>	extends BulkTask<K,V,K> {
5362	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5363	>	K result;
5364	>	ReduceKeysTask<K,V> rights, nextRight;
5365	>	ReduceKeysTask
5366	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5367	>	ReduceKeysTask<K,V> nextRight,
5368	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5369	>	super(p, b, i, f, t); this.nextRight = nextRight;
5370	>	this.reducer = reducer;
5371	>	}
5372	>	public final K getRawResult() { return result; }
5373	>	public final void compute() {
5374	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5375	>	if ((reducer = this.reducer) != null) {
5376	>	for (int i = baseIndex, f, h; batch > 0 &&
5377	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5378	>	addToPendingCount(1);
5379	>	(rights = new ReduceKeysTask<K,V>
5380	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5381	>	rights, reducer)).fork();
5382	>	}
5383	>	K r = null;
5384	>	for (Node<K,V> p; (p = advance()) != null; ) {
5385	>	K u = p.key;
5386	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5387	>	}
5388	>	result = r;
5389	>	CountedCompleter<?> c;
5390	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5391	>	@SuppressWarnings("unchecked")
5392	>	ReduceKeysTask<K,V>
5393	>	t = (ReduceKeysTask<K,V>)c,
5394	>	s = t.rights;
5395	>	while (s != null) {
5396	>	K tr, sr;
5397	>	if ((sr = s.result) != null)
5398	>	t.result = (((tr = t.result) == null) ? sr :
5399	>	reducer.apply(tr, sr));
5400	>	s = t.rights = s.nextRight;
5401	>	}
5402	>	}
5403	>	}
5404		}
5405	<	public <T> T[] toArray(T[] a) {
5406	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
5407	<	for (Iterator<Map.Entry<K,V>> i = iterator(); i.hasNext(); )
5408	<	c.add(new SimpleEntry<K,V>(i.next()));
5409	<	return c.toArray(a);
5405	>	}
5406	>
5407	>	@SuppressWarnings("serial")
5408	>	static final class ReduceValuesTask<K,V>
5409	>	extends BulkTask<K,V,V> {
5410	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5411	>	V result;
5412	>	ReduceValuesTask<K,V> rights, nextRight;
5413	>	ReduceValuesTask
5414	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5415	>	ReduceValuesTask<K,V> nextRight,
5416	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5417	>	super(p, b, i, f, t); this.nextRight = nextRight;
5418	>	this.reducer = reducer;
5419	>	}
5420	>	public final V getRawResult() { return result; }
5421	>	public final void compute() {
5422	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5423	>	if ((reducer = this.reducer) != null) {
5424	>	for (int i = baseIndex, f, h; batch > 0 &&
5425	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5426	>	addToPendingCount(1);
5427	>	(rights = new ReduceValuesTask<K,V>
5428	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5429	>	rights, reducer)).fork();
5430	>	}
5431	>	V r = null;
5432	>	for (Node<K,V> p; (p = advance()) != null; ) {
5433	>	V v = p.val;
5434	>	r = (r == null) ? v : reducer.apply(r, v);
5435	>	}
5436	>	result = r;
5437	>	CountedCompleter<?> c;
5438	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5439	>	@SuppressWarnings("unchecked")
5440	>	ReduceValuesTask<K,V>
5441	>	t = (ReduceValuesTask<K,V>)c,
5442	>	s = t.rights;
5443	>	while (s != null) {
5444	>	V tr, sr;
5445	>	if ((sr = s.result) != null)
5446	>	t.result = (((tr = t.result) == null) ? sr :
5447	>	reducer.apply(tr, sr));
5448	>	s = t.rights = s.nextRight;
5449	>	}
5450	>	}
5451	>	}
5452		}
5453	+	}
5454
5455	+	@SuppressWarnings("serial")
5456	+	static final class ReduceEntriesTask<K,V>
5457	+	extends BulkTask<K,V,Map.Entry<K,V>> {
5458	+	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5459	+	Map.Entry<K,V> result;
5460	+	ReduceEntriesTask<K,V> rights, nextRight;
5461	+	ReduceEntriesTask
5462	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5463	+	ReduceEntriesTask<K,V> nextRight,
5464	+	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5465	+	super(p, b, i, f, t); this.nextRight = nextRight;
5466	+	this.reducer = reducer;
5467	+	}
5468	+	public final Map.Entry<K,V> getRawResult() { return result; }
5469	+	public final void compute() {
5470	+	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5471	+	if ((reducer = this.reducer) != null) {
5472	+	for (int i = baseIndex, f, h; batch > 0 &&
5473	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5474	+	addToPendingCount(1);
5475	+	(rights = new ReduceEntriesTask<K,V>
5476	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5477	+	rights, reducer)).fork();
5478	+	}
5479	+	Map.Entry<K,V> r = null;
5480	+	for (Node<K,V> p; (p = advance()) != null; )
5481	+	r = (r == null) ? p : reducer.apply(r, p);
5482	+	result = r;
5483	+	CountedCompleter<?> c;
5484	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5485	+	@SuppressWarnings("unchecked")
5486	+	ReduceEntriesTask<K,V>
5487	+	t = (ReduceEntriesTask<K,V>)c,
5488	+	s = t.rights;
5489	+	while (s != null) {
5490	+	Map.Entry<K,V> tr, sr;
5491	+	if ((sr = s.result) != null)
5492	+	t.result = (((tr = t.result) == null) ? sr :
5493	+	reducer.apply(tr, sr));
5494	+	s = t.rights = s.nextRight;
5495	+	}
5496	+	}
5497	+	}
5498	+	}
5499		}
5500
5501	<	/**
5502	<	* This duplicates java.util.AbstractMap.SimpleEntry until this class
5503	<	* is made accessible.
5504	<	*/
5505	<	static class SimpleEntry<K,V> implements Entry<K,V> {
5506	<	K key;
5507	<	V value;
5501	>	@SuppressWarnings("serial")
5502	>	static final class MapReduceKeysTask<K,V,U>
5503	>	extends BulkTask<K,V,U> {
5504	>	final Function<? super K, ? extends U> transformer;
5505	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5506	>	U result;
5507	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5508	>	MapReduceKeysTask
5509	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5510	>	MapReduceKeysTask<K,V,U> nextRight,
5511	>	Function<? super K, ? extends U> transformer,
5512	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5513	>	super(p, b, i, f, t); this.nextRight = nextRight;
5514	>	this.transformer = transformer;
5515	>	this.reducer = reducer;
5516	>	}
5517	>	public final U getRawResult() { return result; }
5518	>	public final void compute() {
5519	>	final Function<? super K, ? extends U> transformer;
5520	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5521	>	if ((transformer = this.transformer) != null &&
5522	>	(reducer = this.reducer) != null) {
5523	>	for (int i = baseIndex, f, h; batch > 0 &&
5524	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5525	>	addToPendingCount(1);
5526	>	(rights = new MapReduceKeysTask<K,V,U>
5527	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5528	>	rights, transformer, reducer)).fork();
5529	>	}
5530	>	U r = null;
5531	>	for (Node<K,V> p; (p = advance()) != null; ) {
5532	>	U u;
5533	>	if ((u = transformer.apply(p.key)) != null)
5534	>	r = (r == null) ? u : reducer.apply(r, u);
5535	>	}
5536	>	result = r;
5537	>	CountedCompleter<?> c;
5538	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5539	>	@SuppressWarnings("unchecked")
5540	>	MapReduceKeysTask<K,V,U>
5541	>	t = (MapReduceKeysTask<K,V,U>)c,
5542	>	s = t.rights;
5543	>	while (s != null) {
5544	>	U tr, sr;
5545	>	if ((sr = s.result) != null)
5546	>	t.result = (((tr = t.result) == null) ? sr :
5547	>	reducer.apply(tr, sr));
5548	>	s = t.rights = s.nextRight;
5549	>	}
5550	>	}
5551	>	}
5552	>	}
5553	>	}
5554
5555	<	public SimpleEntry(K key, V value) {
5556	<	this.key   = key;
5557	<	this.value = value;
5558	<	}
5555	>	@SuppressWarnings("serial")
5556	>	static final class MapReduceValuesTask<K,V,U>
5557	>	extends BulkTask<K,V,U> {
5558	>	final Function<? super V, ? extends U> transformer;
5559	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5560	>	U result;
5561	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5562	>	MapReduceValuesTask
5563	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5564	>	MapReduceValuesTask<K,V,U> nextRight,
5565	>	Function<? super V, ? extends U> transformer,
5566	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5567	>	super(p, b, i, f, t); this.nextRight = nextRight;
5568	>	this.transformer = transformer;
5569	>	this.reducer = reducer;
5570	>	}
5571	>	public final U getRawResult() { return result; }
5572	>	public final void compute() {
5573	>	final Function<? super V, ? extends U> transformer;
5574	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5575	>	if ((transformer = this.transformer) != null &&
5576	>	(reducer = this.reducer) != null) {
5577	>	for (int i = baseIndex, f, h; batch > 0 &&
5578	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5579	>	addToPendingCount(1);
5580	>	(rights = new MapReduceValuesTask<K,V,U>
5581	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5582	>	rights, transformer, reducer)).fork();
5583	>	}
5584	>	U r = null;
5585	>	for (Node<K,V> p; (p = advance()) != null; ) {
5586	>	U u;
5587	>	if ((u = transformer.apply(p.val)) != null)
5588	>	r = (r == null) ? u : reducer.apply(r, u);
5589	>	}
5590	>	result = r;
5591	>	CountedCompleter<?> c;
5592	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5593	>	@SuppressWarnings("unchecked")
5594	>	MapReduceValuesTask<K,V,U>
5595	>	t = (MapReduceValuesTask<K,V,U>)c,
5596	>	s = t.rights;
5597	>	while (s != null) {
5598	>	U tr, sr;
5599	>	if ((sr = s.result) != null)
5600	>	t.result = (((tr = t.result) == null) ? sr :
5601	>	reducer.apply(tr, sr));
5602	>	s = t.rights = s.nextRight;
5603	>	}
5604	>	}
5605	>	}
5606	>	}
5607	>	}
5608
5609	<	public SimpleEntry(Entry<K,V> e) {
5610	<	this.key   = e.getKey();
5611	<	this.value = e.getValue();
5612	<	}
5609	>	@SuppressWarnings("serial")
5610	>	static final class MapReduceEntriesTask<K,V,U>
5611	>	extends BulkTask<K,V,U> {
5612	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5613	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5614	>	U result;
5615	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5616	>	MapReduceEntriesTask
5617	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5618	>	MapReduceEntriesTask<K,V,U> nextRight,
5619	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5620	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5621	>	super(p, b, i, f, t); this.nextRight = nextRight;
5622	>	this.transformer = transformer;
5623	>	this.reducer = reducer;
5624	>	}
5625	>	public final U getRawResult() { return result; }
5626	>	public final void compute() {
5627	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5628	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5629	>	if ((transformer = this.transformer) != null &&
5630	>	(reducer = this.reducer) != null) {
5631	>	for (int i = baseIndex, f, h; batch > 0 &&
5632	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5633	>	addToPendingCount(1);
5634	>	(rights = new MapReduceEntriesTask<K,V,U>
5635	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5636	>	rights, transformer, reducer)).fork();
5637	>	}
5638	>	U r = null;
5639	>	for (Node<K,V> p; (p = advance()) != null; ) {
5640	>	U u;
5641	>	if ((u = transformer.apply(p)) != null)
5642	>	r = (r == null) ? u : reducer.apply(r, u);
5643	>	}
5644	>	result = r;
5645	>	CountedCompleter<?> c;
5646	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5647	>	@SuppressWarnings("unchecked")
5648	>	MapReduceEntriesTask<K,V,U>
5649	>	t = (MapReduceEntriesTask<K,V,U>)c,
5650	>	s = t.rights;
5651	>	while (s != null) {
5652	>	U tr, sr;
5653	>	if ((sr = s.result) != null)
5654	>	t.result = (((tr = t.result) == null) ? sr :
5655	>	reducer.apply(tr, sr));
5656	>	s = t.rights = s.nextRight;
5657	>	}
5658	>	}
5659	>	}
5660	>	}
5661	>	}
5662
5663	<	public K getKey() {
5664	<	return key;
5665	<	}
5663	>	@SuppressWarnings("serial")
5664	>	static final class MapReduceMappingsTask<K,V,U>
5665	>	extends BulkTask<K,V,U> {
5666	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5667	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5668	>	U result;
5669	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5670	>	MapReduceMappingsTask
5671	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5672	>	MapReduceMappingsTask<K,V,U> nextRight,
5673	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5674	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5675	>	super(p, b, i, f, t); this.nextRight = nextRight;
5676	>	this.transformer = transformer;
5677	>	this.reducer = reducer;
5678	>	}
5679	>	public final U getRawResult() { return result; }
5680	>	public final void compute() {
5681	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5682	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5683	>	if ((transformer = this.transformer) != null &&
5684	>	(reducer = this.reducer) != null) {
5685	>	for (int i = baseIndex, f, h; batch > 0 &&
5686	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5687	>	addToPendingCount(1);
5688	>	(rights = new MapReduceMappingsTask<K,V,U>
5689	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5690	>	rights, transformer, reducer)).fork();
5691	>	}
5692	>	U r = null;
5693	>	for (Node<K,V> p; (p = advance()) != null; ) {
5694	>	U u;
5695	>	if ((u = transformer.apply(p.key, p.val)) != null)
5696	>	r = (r == null) ? u : reducer.apply(r, u);
5697	>	}
5698	>	result = r;
5699	>	CountedCompleter<?> c;
5700	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5701	>	@SuppressWarnings("unchecked")
5702	>	MapReduceMappingsTask<K,V,U>
5703	>	t = (MapReduceMappingsTask<K,V,U>)c,
5704	>	s = t.rights;
5705	>	while (s != null) {
5706	>	U tr, sr;
5707	>	if ((sr = s.result) != null)
5708	>	t.result = (((tr = t.result) == null) ? sr :
5709	>	reducer.apply(tr, sr));
5710	>	s = t.rights = s.nextRight;
5711	>	}
5712	>	}
5713	>	}
5714	>	}
5715	>	}
5716
5717	<	public V getValue() {
5718	<	return value;
5719	<	}
5717	>	@SuppressWarnings("serial")
5718	>	static final class MapReduceKeysToDoubleTask<K,V>
5719	>	extends BulkTask<K,V,Double> {
5720	>	final ToDoubleFunction<? super K> transformer;
5721	>	final DoubleBinaryOperator reducer;
5722	>	final double basis;
5723	>	double result;
5724	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5725	>	MapReduceKeysToDoubleTask
5726	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5727	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5728	>	ToDoubleFunction<? super K> transformer,
5729	>	double basis,
5730	>	DoubleBinaryOperator reducer) {
5731	>	super(p, b, i, f, t); this.nextRight = nextRight;
5732	>	this.transformer = transformer;
5733	>	this.basis = basis; this.reducer = reducer;
5734	>	}
5735	>	public final Double getRawResult() { return result; }
5736	>	public final void compute() {
5737	>	final ToDoubleFunction<? super K> transformer;
5738	>	final DoubleBinaryOperator reducer;
5739	>	if ((transformer = this.transformer) != null &&
5740	>	(reducer = this.reducer) != null) {
5741	>	double r = this.basis;
5742	>	for (int i = baseIndex, f, h; batch > 0 &&
5743	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5744	>	addToPendingCount(1);
5745	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5746	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5747	>	rights, transformer, r, reducer)).fork();
5748	>	}
5749	>	for (Node<K,V> p; (p = advance()) != null; )
5750	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5751	>	result = r;
5752	>	CountedCompleter<?> c;
5753	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5754	>	@SuppressWarnings("unchecked")
5755	>	MapReduceKeysToDoubleTask<K,V>
5756	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5757	>	s = t.rights;
5758	>	while (s != null) {
5759	>	t.result = reducer.applyAsDouble(t.result, s.result);
5760	>	s = t.rights = s.nextRight;
5761	>	}
5762	>	}
5763	>	}
5764	>	}
5765	>	}
5766
5767	<	public V setValue(V value) {
5768	<	V oldValue = this.value;
5769	<	this.value = value;
5770	<	return oldValue;
5771	<	}
5767	>	@SuppressWarnings("serial")
5768	>	static final class MapReduceValuesToDoubleTask<K,V>
5769	>	extends BulkTask<K,V,Double> {
5770	>	final ToDoubleFunction<? super V> transformer;
5771	>	final DoubleBinaryOperator reducer;
5772	>	final double basis;
5773	>	double result;
5774	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5775	>	MapReduceValuesToDoubleTask
5776	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5777	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5778	>	ToDoubleFunction<? super V> transformer,
5779	>	double basis,
5780	>	DoubleBinaryOperator reducer) {
5781	>	super(p, b, i, f, t); this.nextRight = nextRight;
5782	>	this.transformer = transformer;
5783	>	this.basis = basis; this.reducer = reducer;
5784	>	}
5785	>	public final Double getRawResult() { return result; }
5786	>	public final void compute() {
5787	>	final ToDoubleFunction<? super V> transformer;
5788	>	final DoubleBinaryOperator reducer;
5789	>	if ((transformer = this.transformer) != null &&
5790	>	(reducer = this.reducer) != null) {
5791	>	double r = this.basis;
5792	>	for (int i = baseIndex, f, h; batch > 0 &&
5793	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5794	>	addToPendingCount(1);
5795	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5796	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5797	>	rights, transformer, r, reducer)).fork();
5798	>	}
5799	>	for (Node<K,V> p; (p = advance()) != null; )
5800	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5801	>	result = r;
5802	>	CountedCompleter<?> c;
5803	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5804	>	@SuppressWarnings("unchecked")
5805	>	MapReduceValuesToDoubleTask<K,V>
5806	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5807	>	s = t.rights;
5808	>	while (s != null) {
5809	>	t.result = reducer.applyAsDouble(t.result, s.result);
5810	>	s = t.rights = s.nextRight;
5811	>	}
5812	>	}
5813	>	}
5814	>	}
5815	>	}
5816
5817	<	public boolean equals(Object o) {
5818	<	if (!(o instanceof Map.Entry))
5819	<	return false;
5820	<	Map.Entry e = (Map.Entry)o;
5821	<	return eq(key, e.getKey()) && eq(value, e.getValue());
5822	<	}
5817	>	@SuppressWarnings("serial")
5818	>	static final class MapReduceEntriesToDoubleTask<K,V>
5819	>	extends BulkTask<K,V,Double> {
5820	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5821	>	final DoubleBinaryOperator reducer;
5822	>	final double basis;
5823	>	double result;
5824	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5825	>	MapReduceEntriesToDoubleTask
5826	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5827	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5828	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5829	>	double basis,
5830	>	DoubleBinaryOperator reducer) {
5831	>	super(p, b, i, f, t); this.nextRight = nextRight;
5832	>	this.transformer = transformer;
5833	>	this.basis = basis; this.reducer = reducer;
5834	>	}
5835	>	public final Double getRawResult() { return result; }
5836	>	public final void compute() {
5837	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5838	>	final DoubleBinaryOperator reducer;
5839	>	if ((transformer = this.transformer) != null &&
5840	>	(reducer = this.reducer) != null) {
5841	>	double r = this.basis;
5842	>	for (int i = baseIndex, f, h; batch > 0 &&
5843	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5844	>	addToPendingCount(1);
5845	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5846	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5847	>	rights, transformer, r, reducer)).fork();
5848	>	}
5849	>	for (Node<K,V> p; (p = advance()) != null; )
5850	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5851	>	result = r;
5852	>	CountedCompleter<?> c;
5853	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5854	>	@SuppressWarnings("unchecked")
5855	>	MapReduceEntriesToDoubleTask<K,V>
5856	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5857	>	s = t.rights;
5858	>	while (s != null) {
5859	>	t.result = reducer.applyAsDouble(t.result, s.result);
5860	>	s = t.rights = s.nextRight;
5861	>	}
5862	>	}
5863	>	}
5864	>	}
5865	>	}
5866
5867	<	public int hashCode() {
5868	<	return ((key   == null)   ? 0 :   key.hashCode()) ^
5869	<	((value == null)   ? 0 : value.hashCode());
5870	<	}
5867	>	@SuppressWarnings("serial")
5868	>	static final class MapReduceMappingsToDoubleTask<K,V>
5869	>	extends BulkTask<K,V,Double> {
5870	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5871	>	final DoubleBinaryOperator reducer;
5872	>	final double basis;
5873	>	double result;
5874	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5875	>	MapReduceMappingsToDoubleTask
5876	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5877	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5878	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5879	>	double basis,
5880	>	DoubleBinaryOperator reducer) {
5881	>	super(p, b, i, f, t); this.nextRight = nextRight;
5882	>	this.transformer = transformer;
5883	>	this.basis = basis; this.reducer = reducer;
5884	>	}
5885	>	public final Double getRawResult() { return result; }
5886	>	public final void compute() {
5887	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5888	>	final DoubleBinaryOperator reducer;
5889	>	if ((transformer = this.transformer) != null &&
5890	>	(reducer = this.reducer) != null) {
5891	>	double r = this.basis;
5892	>	for (int i = baseIndex, f, h; batch > 0 &&
5893	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5894	>	addToPendingCount(1);
5895	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5896	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5897	>	rights, transformer, r, reducer)).fork();
5898	>	}
5899	>	for (Node<K,V> p; (p = advance()) != null; )
5900	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5901	>	result = r;
5902	>	CountedCompleter<?> c;
5903	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5904	>	@SuppressWarnings("unchecked")
5905	>	MapReduceMappingsToDoubleTask<K,V>
5906	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5907	>	s = t.rights;
5908	>	while (s != null) {
5909	>	t.result = reducer.applyAsDouble(t.result, s.result);
5910	>	s = t.rights = s.nextRight;
5911	>	}
5912	>	}
5913	>	}
5914	>	}
5915	>	}
5916
5917	<	public String toString() {
5918	<	return key + "=" + value;
5919	<	}
5917	>	@SuppressWarnings("serial")
5918	>	static final class MapReduceKeysToLongTask<K,V>
5919	>	extends BulkTask<K,V,Long> {
5920	>	final ToLongFunction<? super K> transformer;
5921	>	final LongBinaryOperator reducer;
5922	>	final long basis;
5923	>	long result;
5924	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5925	>	MapReduceKeysToLongTask
5926	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5927	>	MapReduceKeysToLongTask<K,V> nextRight,
5928	>	ToLongFunction<? super K> transformer,
5929	>	long basis,
5930	>	LongBinaryOperator reducer) {
5931	>	super(p, b, i, f, t); this.nextRight = nextRight;
5932	>	this.transformer = transformer;
5933	>	this.basis = basis; this.reducer = reducer;
5934	>	}
5935	>	public final Long getRawResult() { return result; }
5936	>	public final void compute() {
5937	>	final ToLongFunction<? super K> transformer;
5938	>	final LongBinaryOperator reducer;
5939	>	if ((transformer = this.transformer) != null &&
5940	>	(reducer = this.reducer) != null) {
5941	>	long r = this.basis;
5942	>	for (int i = baseIndex, f, h; batch > 0 &&
5943	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5944	>	addToPendingCount(1);
5945	>	(rights = new MapReduceKeysToLongTask<K,V>
5946	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5947	>	rights, transformer, r, reducer)).fork();
5948	>	}
5949	>	for (Node<K,V> p; (p = advance()) != null; )
5950	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5951	>	result = r;
5952	>	CountedCompleter<?> c;
5953	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5954	>	@SuppressWarnings("unchecked")
5955	>	MapReduceKeysToLongTask<K,V>
5956	>	t = (MapReduceKeysToLongTask<K,V>)c,
5957	>	s = t.rights;
5958	>	while (s != null) {
5959	>	t.result = reducer.applyAsLong(t.result, s.result);
5960	>	s = t.rights = s.nextRight;
5961	>	}
5962	>	}
5963	>	}
5964	>	}
5965	>	}
5966
5967	<	private static boolean eq(Object o1, Object o2) {
5968	<	return (o1 == null ? o2 == null : o1.equals(o2));
5967	>	@SuppressWarnings("serial")
5968	>	static final class MapReduceValuesToLongTask<K,V>
5969	>	extends BulkTask<K,V,Long> {
5970	>	final ToLongFunction<? super V> transformer;
5971	>	final LongBinaryOperator reducer;
5972	>	final long basis;
5973	>	long result;
5974	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5975	>	MapReduceValuesToLongTask
5976	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5977	>	MapReduceValuesToLongTask<K,V> nextRight,
5978	>	ToLongFunction<? super V> transformer,
5979	>	long basis,
5980	>	LongBinaryOperator reducer) {
5981	>	super(p, b, i, f, t); this.nextRight = nextRight;
5982	>	this.transformer = transformer;
5983	>	this.basis = basis; this.reducer = reducer;
5984	>	}
5985	>	public final Long getRawResult() { return result; }
5986	>	public final void compute() {
5987	>	final ToLongFunction<? super V> transformer;
5988	>	final LongBinaryOperator reducer;
5989	>	if ((transformer = this.transformer) != null &&
5990	>	(reducer = this.reducer) != null) {
5991	>	long r = this.basis;
5992	>	for (int i = baseIndex, f, h; batch > 0 &&
5993	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5994	>	addToPendingCount(1);
5995	>	(rights = new MapReduceValuesToLongTask<K,V>
5996	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5997	>	rights, transformer, r, reducer)).fork();
5998	>	}
5999	>	for (Node<K,V> p; (p = advance()) != null; )
6000	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
6001	>	result = r;
6002	>	CountedCompleter<?> c;
6003	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6004	>	@SuppressWarnings("unchecked")
6005	>	MapReduceValuesToLongTask<K,V>
6006	>	t = (MapReduceValuesToLongTask<K,V>)c,
6007	>	s = t.rights;
6008	>	while (s != null) {
6009	>	t.result = reducer.applyAsLong(t.result, s.result);
6010	>	s = t.rights = s.nextRight;
6011	>	}
6012	>	}
6013	>	}
6014		}
6015		}
6016
6017	<	/* ---------------- Serialization Support -------------- */
6017	>	@SuppressWarnings("serial")
6018	>	static final class MapReduceEntriesToLongTask<K,V>
6019	>	extends BulkTask<K,V,Long> {
6020	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6021	>	final LongBinaryOperator reducer;
6022	>	final long basis;
6023	>	long result;
6024	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6025	>	MapReduceEntriesToLongTask
6026	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6027	>	MapReduceEntriesToLongTask<K,V> nextRight,
6028	>	ToLongFunction<Map.Entry<K,V>> transformer,
6029	>	long basis,
6030	>	LongBinaryOperator reducer) {
6031	>	super(p, b, i, f, t); this.nextRight = nextRight;
6032	>	this.transformer = transformer;
6033	>	this.basis = basis; this.reducer = reducer;
6034	>	}
6035	>	public final Long getRawResult() { return result; }
6036	>	public final void compute() {
6037	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6038	>	final LongBinaryOperator reducer;
6039	>	if ((transformer = this.transformer) != null &&
6040	>	(reducer = this.reducer) != null) {
6041	>	long r = this.basis;
6042	>	for (int i = baseIndex, f, h; batch > 0 &&
6043	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6044	>	addToPendingCount(1);
6045	>	(rights = new MapReduceEntriesToLongTask<K,V>
6046	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6047	>	rights, transformer, r, reducer)).fork();
6048	>	}
6049	>	for (Node<K,V> p; (p = advance()) != null; )
6050	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6051	>	result = r;
6052	>	CountedCompleter<?> c;
6053	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6054	>	@SuppressWarnings("unchecked")
6055	>	MapReduceEntriesToLongTask<K,V>
6056	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6057	>	s = t.rights;
6058	>	while (s != null) {
6059	>	t.result = reducer.applyAsLong(t.result, s.result);
6060	>	s = t.rights = s.nextRight;
6061	>	}
6062	>	}
6063	>	}
6064	>	}
6065	>	}
6066
6067	<	/**
6068	<	* Save the state of the <tt>ConcurrentHashMap</tt>
6069	<	* instance to a stream (i.e.,
6070	<	* serialize it).
6071	<	* @param s the stream
6072	<	* @serialData
6073	<	* the key (Object) and value (Object)
6074	<	* for each key-value mapping, followed by a null pair.
6075	<	* The key-value mappings are emitted in no particular order.
6076	<	*/
6077	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
6078	<	s.defaultWriteObject();
6067	>	@SuppressWarnings("serial")
6068	>	static final class MapReduceMappingsToLongTask<K,V>
6069	>	extends BulkTask<K,V,Long> {
6070	>	final ToLongBiFunction<? super K, ? super V> transformer;
6071	>	final LongBinaryOperator reducer;
6072	>	final long basis;
6073	>	long result;
6074	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6075	>	MapReduceMappingsToLongTask
6076	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6077	>	MapReduceMappingsToLongTask<K,V> nextRight,
6078	>	ToLongBiFunction<? super K, ? super V> transformer,
6079	>	long basis,
6080	>	LongBinaryOperator reducer) {
6081	>	super(p, b, i, f, t); this.nextRight = nextRight;
6082	>	this.transformer = transformer;
6083	>	this.basis = basis; this.reducer = reducer;
6084	>	}
6085	>	public final Long getRawResult() { return result; }
6086	>	public final void compute() {
6087	>	final ToLongBiFunction<? super K, ? super V> transformer;
6088	>	final LongBinaryOperator reducer;
6089	>	if ((transformer = this.transformer) != null &&
6090	>	(reducer = this.reducer) != null) {
6091	>	long r = this.basis;
6092	>	for (int i = baseIndex, f, h; batch > 0 &&
6093	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6094	>	addToPendingCount(1);
6095	>	(rights = new MapReduceMappingsToLongTask<K,V>
6096	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6097	>	rights, transformer, r, reducer)).fork();
6098	>	}
6099	>	for (Node<K,V> p; (p = advance()) != null; )
6100	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6101	>	result = r;
6102	>	CountedCompleter<?> c;
6103	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6104	>	@SuppressWarnings("unchecked")
6105	>	MapReduceMappingsToLongTask<K,V>
6106	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6107	>	s = t.rights;
6108	>	while (s != null) {
6109	>	t.result = reducer.applyAsLong(t.result, s.result);
6110	>	s = t.rights = s.nextRight;
6111	>	}
6112	>	}
6113	>	}
6114	>	}
6115	>	}
6116
6117	<	for (int k = 0; k < segments.length; ++k) {
6118	<	Segment<K,V> seg = (Segment<K,V>)segments[k];
6119	<	seg.lock();
6120	<	try {
6121	<	HashEntry[] tab = seg.table;
6122	<	for (int i = 0; i < tab.length; ++i) {
6123	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i]; e != null; e = e.next) {
6124	<	s.writeObject(e.key);
6125	<	s.writeObject(e.value);
6117	>	@SuppressWarnings("serial")
6118	>	static final class MapReduceKeysToIntTask<K,V>
6119	>	extends BulkTask<K,V,Integer> {
6120	>	final ToIntFunction<? super K> transformer;
6121	>	final IntBinaryOperator reducer;
6122	>	final int basis;
6123	>	int result;
6124	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6125	>	MapReduceKeysToIntTask
6126	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6127	>	MapReduceKeysToIntTask<K,V> nextRight,
6128	>	ToIntFunction<? super K> transformer,
6129	>	int basis,
6130	>	IntBinaryOperator reducer) {
6131	>	super(p, b, i, f, t); this.nextRight = nextRight;
6132	>	this.transformer = transformer;
6133	>	this.basis = basis; this.reducer = reducer;
6134	>	}
6135	>	public final Integer getRawResult() { return result; }
6136	>	public final void compute() {
6137	>	final ToIntFunction<? super K> transformer;
6138	>	final IntBinaryOperator reducer;
6139	>	if ((transformer = this.transformer) != null &&
6140	>	(reducer = this.reducer) != null) {
6141	>	int r = this.basis;
6142	>	for (int i = baseIndex, f, h; batch > 0 &&
6143	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6144	>	addToPendingCount(1);
6145	>	(rights = new MapReduceKeysToIntTask<K,V>
6146	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6147	>	rights, transformer, r, reducer)).fork();
6148	>	}
6149	>	for (Node<K,V> p; (p = advance()) != null; )
6150	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6151	>	result = r;
6152	>	CountedCompleter<?> c;
6153	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6154	>	@SuppressWarnings("unchecked")
6155	>	MapReduceKeysToIntTask<K,V>
6156	>	t = (MapReduceKeysToIntTask<K,V>)c,
6157	>	s = t.rights;
6158	>	while (s != null) {
6159	>	t.result = reducer.applyAsInt(t.result, s.result);
6160	>	s = t.rights = s.nextRight;
6161		}
6162		}
1304	–	} finally {
1305	–	seg.unlock();
6163		}
6164		}
1308	–	s.writeObject(null);
1309	–	s.writeObject(null);
6165		}
6166
6167	<	/**
6168	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
6169	<	* instance from a stream (i.e.,
6170	<	* deserialize it).
6171	<	* @param s the stream
6172	<	*/
6173	<	private void readObject(java.io.ObjectInputStream s)
6174	<	throws IOException, ClassNotFoundException  {
6175	<	s.defaultReadObject();
6167	>	@SuppressWarnings("serial")
6168	>	static final class MapReduceValuesToIntTask<K,V>
6169	>	extends BulkTask<K,V,Integer> {
6170	>	final ToIntFunction<? super V> transformer;
6171	>	final IntBinaryOperator reducer;
6172	>	final int basis;
6173	>	int result;
6174	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6175	>	MapReduceValuesToIntTask
6176	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6177	>	MapReduceValuesToIntTask<K,V> nextRight,
6178	>	ToIntFunction<? super V> transformer,
6179	>	int basis,
6180	>	IntBinaryOperator reducer) {
6181	>	super(p, b, i, f, t); this.nextRight = nextRight;
6182	>	this.transformer = transformer;
6183	>	this.basis = basis; this.reducer = reducer;
6184	>	}
6185	>	public final Integer getRawResult() { return result; }
6186	>	public final void compute() {
6187	>	final ToIntFunction<? super V> transformer;
6188	>	final IntBinaryOperator reducer;
6189	>	if ((transformer = this.transformer) != null &&
6190	>	(reducer = this.reducer) != null) {
6191	>	int r = this.basis;
6192	>	for (int i = baseIndex, f, h; batch > 0 &&
6193	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6194	>	addToPendingCount(1);
6195	>	(rights = new MapReduceValuesToIntTask<K,V>
6196	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6197	>	rights, transformer, r, reducer)).fork();
6198	>	}
6199	>	for (Node<K,V> p; (p = advance()) != null; )
6200	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6201	>	result = r;
6202	>	CountedCompleter<?> c;
6203	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6204	>	@SuppressWarnings("unchecked")
6205	>	MapReduceValuesToIntTask<K,V>
6206	>	t = (MapReduceValuesToIntTask<K,V>)c,
6207	>	s = t.rights;
6208	>	while (s != null) {
6209	>	t.result = reducer.applyAsInt(t.result, s.result);
6210	>	s = t.rights = s.nextRight;
6211	>	}
6212	>	}
6213	>	}
6214	>	}
6215	>	}
6216
6217	<	// Initialize each segment to be minimally sized, and let grow.
6218	<	for (int i = 0; i < segments.length; ++i) {
6219	<	segments[i].setTable(new HashEntry[1]);
6217	>	@SuppressWarnings("serial")
6218	>	static final class MapReduceEntriesToIntTask<K,V>
6219	>	extends BulkTask<K,V,Integer> {
6220	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6221	>	final IntBinaryOperator reducer;
6222	>	final int basis;
6223	>	int result;
6224	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6225	>	MapReduceEntriesToIntTask
6226	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6227	>	MapReduceEntriesToIntTask<K,V> nextRight,
6228	>	ToIntFunction<Map.Entry<K,V>> transformer,
6229	>	int basis,
6230	>	IntBinaryOperator reducer) {
6231	>	super(p, b, i, f, t); this.nextRight = nextRight;
6232	>	this.transformer = transformer;
6233	>	this.basis = basis; this.reducer = reducer;
6234	>	}
6235	>	public final Integer getRawResult() { return result; }
6236	>	public final void compute() {
6237	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6238	>	final IntBinaryOperator reducer;
6239	>	if ((transformer = this.transformer) != null &&
6240	>	(reducer = this.reducer) != null) {
6241	>	int r = this.basis;
6242	>	for (int i = baseIndex, f, h; batch > 0 &&
6243	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6244	>	addToPendingCount(1);
6245	>	(rights = new MapReduceEntriesToIntTask<K,V>
6246	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6247	>	rights, transformer, r, reducer)).fork();
6248	>	}
6249	>	for (Node<K,V> p; (p = advance()) != null; )
6250	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6251	>	result = r;
6252	>	CountedCompleter<?> c;
6253	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6254	>	@SuppressWarnings("unchecked")
6255	>	MapReduceEntriesToIntTask<K,V>
6256	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6257	>	s = t.rights;
6258	>	while (s != null) {
6259	>	t.result = reducer.applyAsInt(t.result, s.result);
6260	>	s = t.rights = s.nextRight;
6261	>	}
6262	>	}
6263	>	}
6264		}
6265	+	}
6266
6267	<	// Read the keys and values, and put the mappings in the table
6268	<	for (;;) {
6269	<	K key = (K) s.readObject();
6270	<	V value = (V) s.readObject();
6271	<	if (key == null)
6272	<	break;
6273	<	put(key, value);
6267	>	@SuppressWarnings("serial")
6268	>	static final class MapReduceMappingsToIntTask<K,V>
6269	>	extends BulkTask<K,V,Integer> {
6270	>	final ToIntBiFunction<? super K, ? super V> transformer;
6271	>	final IntBinaryOperator reducer;
6272	>	final int basis;
6273	>	int result;
6274	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6275	>	MapReduceMappingsToIntTask
6276	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6277	>	MapReduceMappingsToIntTask<K,V> nextRight,
6278	>	ToIntBiFunction<? super K, ? super V> transformer,
6279	>	int basis,
6280	>	IntBinaryOperator reducer) {
6281	>	super(p, b, i, f, t); this.nextRight = nextRight;
6282	>	this.transformer = transformer;
6283	>	this.basis = basis; this.reducer = reducer;
6284	>	}
6285	>	public final Integer getRawResult() { return result; }
6286	>	public final void compute() {
6287	>	final ToIntBiFunction<? super K, ? super V> transformer;
6288	>	final IntBinaryOperator reducer;
6289	>	if ((transformer = this.transformer) != null &&
6290	>	(reducer = this.reducer) != null) {
6291	>	int r = this.basis;
6292	>	for (int i = baseIndex, f, h; batch > 0 &&
6293	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6294	>	addToPendingCount(1);
6295	>	(rights = new MapReduceMappingsToIntTask<K,V>
6296	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6297	>	rights, transformer, r, reducer)).fork();
6298	>	}
6299	>	for (Node<K,V> p; (p = advance()) != null; )
6300	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6301	>	result = r;
6302	>	CountedCompleter<?> c;
6303	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6304	>	@SuppressWarnings("unchecked")
6305	>	MapReduceMappingsToIntTask<K,V>
6306	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6307	>	s = t.rights;
6308	>	while (s != null) {
6309	>	t.result = reducer.applyAsInt(t.result, s.result);
6310	>	s = t.rights = s.nextRight;
6311	>	}
6312	>	}
6313	>	}
6314		}
6315		}
1336	–	}
6316
6317	+	// Unsafe mechanics
6318	+	private static final Unsafe U = Unsafe.getUnsafe();
6319	+	private static final long SIZECTL;
6320	+	private static final long TRANSFERINDEX;
6321	+	private static final long BASECOUNT;
6322	+	private static final long CELLSBUSY;
6323	+	private static final long CELLVALUE;
6324	+	private static final int ABASE;
6325	+	private static final int ASHIFT;
6326	+
6327	+	static {
6328	+	SIZECTL = U.objectFieldOffset
6329	+	(ConcurrentHashMap.class, "sizeCtl");
6330	+	TRANSFERINDEX = U.objectFieldOffset
6331	+	(ConcurrentHashMap.class, "transferIndex");
6332	+	BASECOUNT = U.objectFieldOffset
6333	+	(ConcurrentHashMap.class, "baseCount");
6334	+	CELLSBUSY = U.objectFieldOffset
6335	+	(ConcurrentHashMap.class, "cellsBusy");
6336	+
6337	+	CELLVALUE = U.objectFieldOffset
6338	+	(CounterCell.class, "value");
6339	+
6340	+	ABASE = U.arrayBaseOffset(Node[].class);
6341	+	int scale = U.arrayIndexScale(Node[].class);
6342	+	if ((scale & (scale - 1)) != 0)
6343	+	throw new ExceptionInInitializerError("array index scale not a power of two");
6344	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6345	+
6346	+	// Reduce the risk of rare disastrous classloading in first call to
6347	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6348	+	Class<?> ensureLoaded = LockSupport.class;
6349	+
6350	+	// Eager class load observed to help JIT during startup
6351	+	ensureLoaded = ReservationNode.class;
6352	+	}
6353	+	}

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