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Revision 1.24 by dl, Fri Oct 10 23:51:28 2003 UTC vs.
Revision 1.259 by dl, Mon Dec 22 12:58:17 2014 UTC

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

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