ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

root/jsr166/jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java

Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.7 by brian, Mon Jun 23 02:26:16 2003 UTC vs.
Revision 1.278 by jsr166, Sat Sep 12 21:55:08 2015 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
9	<	import java.util.*;
9	>	import java.io.ObjectStreamField;
10		import java.io.Serializable;
11	<	import java.io.IOException;
12	<	import java.io.ObjectInputStream;
13	<	import java.io.ObjectOutputStream;
11	>	import java.lang.reflect.ParameterizedType;
12	>	import java.lang.reflect.Type;
13	>	import java.util.AbstractMap;
14	>	import java.util.Arrays;
15	>	import java.util.Collection;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.atomic.AtomicReference;
25	>	import java.util.concurrent.locks.LockSupport;
26	>	import java.util.concurrent.locks.ReentrantLock;
27	>	import java.util.function.BiConsumer;
28	>	import java.util.function.BiFunction;
29	>	import java.util.function.Consumer;
30	>	import java.util.function.DoubleBinaryOperator;
31	>	import java.util.function.Function;
32	>	import java.util.function.IntBinaryOperator;
33	>	import java.util.function.LongBinaryOperator;
34	>	import java.util.function.Predicate;
35	>	import java.util.function.ToDoubleBiFunction;
36	>	import java.util.function.ToDoubleFunction;
37	>	import java.util.function.ToIntBiFunction;
38	>	import java.util.function.ToIntFunction;
39	>	import java.util.function.ToLongBiFunction;
40	>	import java.util.function.ToLongFunction;
41	>	import java.util.stream.Stream;
42
43		/**
44		* A hash table supporting full concurrency of retrievals and
45	<	* adjustable expected concurrency for updates. This class obeys the
46	<	* same functional specification as
47	<	* <tt>java.util.Hashtable</tt>. However, even though all operations
48	<	* are thread-safe, retrieval operations do <em>not</em> entail
49	<	* locking, and there is <em>not</em> any support for locking the
50	<	* entire table in a way that prevents all access.  This class is
51	<	* fully interoperable with Hashtable in programs that rely on its
45	>	* high expected concurrency for updates. This class obeys the
46	>	* same functional specification as {@link java.util.Hashtable}, and
47	>	* includes versions of methods corresponding to each method of
48	>	* {@code Hashtable}. However, even though all operations are
49	>	* thread-safe, retrieval operations do <em>not</em> entail locking,
50	>	* and there is <em>not</em> any support for locking the entire table
51	>	* in a way that prevents all access.  This class is fully
52	>	* interoperable with {@code Hashtable} in programs that rely on its
53		* thread safety but not on its synchronization details.
54	<	*
55	<	* <p> Retrieval operations (including <tt>get</tt>) ordinarily
56	<	* overlap with update operations (including <tt>put</tt> and
57	<	* <tt>remove</tt>). Retrievals reflect the results of the most
54	>	*
55	>	* <p>Retrieval operations (including {@code get}) generally do not
56	>	* block, so may overlap with update operations (including {@code put}
57	>	* and {@code remove}). Retrievals reflect the results of the most
58		* recently <em>completed</em> update operations holding upon their
59	<	* onset.  For aggregate operations such as <tt>putAll</tt> and
60	<	* <tt>clear</tt>, concurrent retrievals may reflect insertion or
61	<	* removal of only some entries.  Similarly, Iterators and
62	<	* Enumerations return elements reflecting the state of the hash table
63	<	* at some point at or since the creation of the iterator/enumeration.
64	<	* They do <em>not</em> throw ConcurrentModificationException.
65	<	* However, Iterators are designed to be used by only one thread at a
66	<	* time.
67	<	*
68	<	* <p> The allowed concurrency among update operations is controlled
69	<	* by the optional <tt>segments</tt> constructor argument (default
70	<	* 16). The table is divided into this many independent parts, each of
71	<	* which can be updated concurrently. Because placement in hash tables
72	<	* is essentially random, the actual concurrency will vary. As a rough
73	<	* rule of thumb, you should choose at least as many segments as you
74	<	* expect concurrent threads. However, using more segments than you
75	<	* need can waste space and time. Using a value of 1 for
76	<	* <tt>segments</tt> results in a table that is concurrently readable
77	<	* but can only be updated by one thread at a time.
78	<	*
79	<	* <p> Like Hashtable but unlike java.util.HashMap, this class does
80	<	* NOT allow <tt>null</tt> to be used as a key or value.
81	<	*
82	<	**/
83	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
84	<	implements ConcurrentMap<K, V>, Cloneable, Serializable {
59	>	* onset. (More formally, an update operation for a given key bears a
60	>	* <em>happens-before</em> relation with any (non-null) retrieval for
61	>	* that key reporting the updated value.)  For aggregate operations
62	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
63	>	* reflect insertion or removal of only some entries.  Similarly,
64	>	* Iterators, Spliterators and Enumerations return elements reflecting the
65	>	* state of the hash table at some point at or since the creation of the
66	>	* iterator/enumeration.  They do <em>not</em> throw {@link
67	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
68	>	* However, iterators are designed to be used by only one thread at a time.
69	>	* Bear in mind that the results of aggregate status methods including
70	>	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
71	>	* useful only when a map is not undergoing concurrent updates in other threads.
72	>	* Otherwise the results of these methods reflect transient states
73	>	* that may be adequate for monitoring or estimation purposes, but not
74	>	* for program control.
75	>	*
76	>	* <p>The table is dynamically expanded when there are too many
77	>	* collisions (i.e., keys that have distinct hash codes but fall into
78	>	* the same slot modulo the table size), with the expected average
79	>	* effect of maintaining roughly two bins per mapping (corresponding
80	>	* to a 0.75 load factor threshold for resizing). There may be much
81	>	* variance around this average as mappings are added and removed, but
82	>	* overall, this maintains a commonly accepted time/space tradeoff for
83	>	* hash tables.  However, resizing this or any other kind of hash
84	>	* table may be a relatively slow operation. When possible, it is a
85	>	* good idea to provide a size estimate as an optional {@code
86	>	* initialCapacity} constructor argument. An additional optional
87	>	* {@code loadFactor} constructor argument provides a further means of
88	>	* customizing initial table capacity by specifying the table density
89	>	* to be used in calculating the amount of space to allocate for the
90	>	* given number of elements.  Also, for compatibility with previous
91	>	* versions of this class, constructors may optionally specify an
92	>	* expected {@code concurrencyLevel} as an additional hint for
93	>	* internal sizing.  Note that using many keys with exactly the same
94	>	* {@code hashCode()} is a sure way to slow down performance of any
95	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
96	>	* this class may use comparison order among keys to help break ties.
97	>	*
98	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
99	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
100	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
101	>	* mapped values are (perhaps transiently) not used or all take the
102	>	* same mapping value.
103	>	*
104	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
105	>	* form of histogram or multiset) by using {@link
106	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
107	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
108	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
109	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
110	>	*
111	>	* <p>This class and its views and iterators implement all of the
112	>	* <em>optional</em> methods of the {@link Map} and {@link Iterator}
113	>	* interfaces.
114	>	*
115	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
116	>	* does <em>not</em> allow {@code null} to be used as a key or value.
117	>	*
118	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
119	>	* operations that, unlike most {@link Stream} methods, are designed
120	>	* to be safely, and often sensibly, applied even with maps that are
121	>	* being concurrently updated by other threads; for example, when
122	>	* computing a snapshot summary of the values in a shared registry.
123	>	* There are three kinds of operation, each with four forms, accepting
124	>	* functions with keys, values, entries, and (key, value) pairs as
125	>	* arguments and/or return values. Because the elements of a
126	>	* ConcurrentHashMap are not ordered in any particular way, and may be
127	>	* processed in different orders in different parallel executions, the
128	>	* correctness of supplied functions should not depend on any
129	>	* ordering, or on any other objects or values that may transiently
130	>	* change while computation is in progress; and except for forEach
131	>	* actions, should ideally be side-effect-free. Bulk operations on
132	>	* {@link java.util.Map.Entry} objects do not support method {@code
133	>	* setValue}.
134	>	*
135	>	* <ul>
136	>	* <li> forEach: Perform a given action on each element.
137	>	* A variant form applies a given transformation on each element
138	>	* before performing the action.</li>
139	>	*
140	>	* <li> search: Return the first available non-null result of
141	>	* applying a given function on each element; skipping further
142	>	* search when a result is found.</li>
143	>	*
144	>	* <li> reduce: Accumulate each element.  The supplied reduction
145	>	* function cannot rely on ordering (more formally, it should be
146	>	* both associative and commutative).  There are five variants:
147	>	*
148	>	* <ul>
149	>	*
150	>	* <li> Plain reductions. (There is not a form of this method for
151	>	* (key, value) function arguments since there is no corresponding
152	>	* return type.)</li>
153	>	*
154	>	* <li> Mapped reductions that accumulate the results of a given
155	>	* function applied to each element.</li>
156	>	*
157	>	* <li> Reductions to scalar doubles, longs, and ints, using a
158	>	* given basis value.</li>
159	>	*
160	>	* </ul>
161	>	* </li>
162	>	* </ul>
163	>	*
164	>	* <p>These bulk operations accept a {@code parallelismThreshold}
165	>	* argument. Methods proceed sequentially if the current map size is
166	>	* estimated to be less than the given threshold. Using a value of
167	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
168	>	* of {@code 1} results in maximal parallelism by partitioning into
169	>	* enough subtasks to fully utilize the {@link
170	>	* ForkJoinPool#commonPool()} that is used for all parallel
171	>	* computations. Normally, you would initially choose one of these
172	>	* extreme values, and then measure performance of using in-between
173	>	* values that trade off overhead versus throughput.
174	>	*
175	>	* <p>The concurrency properties of bulk operations follow
176	>	* from those of ConcurrentHashMap: Any non-null result returned
177	>	* from {@code get(key)} and related access methods bears a
178	>	* happens-before relation with the associated insertion or
179	>	* update.  The result of any bulk operation reflects the
180	>	* composition of these per-element relations (but is not
181	>	* necessarily atomic with respect to the map as a whole unless it
182	>	* is somehow known to be quiescent).  Conversely, because keys
183	>	* and values in the map are never null, null serves as a reliable
184	>	* atomic indicator of the current lack of any result.  To
185	>	* maintain this property, null serves as an implicit basis for
186	>	* all non-scalar reduction operations. For the double, long, and
187	>	* int versions, the basis should be one that, when combined with
188	>	* any other value, returns that other value (more formally, it
189	>	* should be the identity element for the reduction). Most common
190	>	* reductions have these properties; for example, computing a sum
191	>	* with basis 0 or a minimum with basis MAX_VALUE.
192	>	*
193	>	* <p>Search and transformation functions provided as arguments
194	>	* should similarly return null to indicate the lack of any result
195	>	* (in which case it is not used). In the case of mapped
196	>	* reductions, this also enables transformations to serve as
197	>	* filters, returning null (or, in the case of primitive
198	>	* specializations, the identity basis) if the element should not
199	>	* be combined. You can create compound transformations and
200	>	* filterings by composing them yourself under this "null means
201	>	* there is nothing there now" rule before using them in search or
202	>	* reduce operations.
203	>	*
204	>	* <p>Methods accepting and/or returning Entry arguments maintain
205	>	* key-value associations. They may be useful for example when
206	>	* finding the key for the greatest value. Note that "plain" Entry
207	>	* arguments can be supplied using {@code new
208	>	* AbstractMap.SimpleEntry(k,v)}.
209	>	*
210	>	* <p>Bulk operations may complete abruptly, throwing an
211	>	* exception encountered in the application of a supplied
212	>	* function. Bear in mind when handling such exceptions that other
213	>	* concurrently executing functions could also have thrown
214	>	* exceptions, or would have done so if the first exception had
215	>	* not occurred.
216	>	*
217	>	* <p>Speedups for parallel compared to sequential forms are common
218	>	* but not guaranteed.  Parallel operations involving brief functions
219	>	* on small maps may execute more slowly than sequential forms if the
220	>	* underlying work to parallelize the computation is more expensive
221	>	* than the computation itself.  Similarly, parallelization may not
222	>	* lead to much actual parallelism if all processors are busy
223	>	* performing unrelated tasks.
224	>	*
225	>	* <p>All arguments to all task methods must be non-null.
226	>	*
227	>	* <p>This class is a member of the
228	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
229	>	* Java Collections Framework</a>.
230	>	*
231	>	* @since 1.5
232	>	* @author Doug Lea
233	>	* @param <K> the type of keys maintained by this map
234	>	* @param <V> the type of mapped values
235	>	*/
236	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
237	>	implements ConcurrentMap<K,V>, Serializable {
238	>	private static final long serialVersionUID = 7249069246763182397L;
239
240		/*
241	<	* The basic strategy is to subdivide the table among Segments,
242	<	* each of which itself is a concurrently readable hash table.
241	>	* Overview:
242	>	*
243	>	* The primary design goal of this hash table is to maintain
244	>	* concurrent readability (typically method get(), but also
245	>	* iterators and related methods) while minimizing update
246	>	* contention. Secondary goals are to keep space consumption about
247	>	* the same or better than java.util.HashMap, and to support high
248	>	* initial insertion rates on an empty table by many threads.
249	>	*
250	>	* This map usually acts as a binned (bucketed) hash table.  Each
251	>	* key-value mapping is held in a Node.  Most nodes are instances
252	>	* of the basic Node class with hash, key, value, and next
253	>	* fields. However, various subclasses exist: TreeNodes are
254	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
255	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
256	>	* of bins during resizing. ReservationNodes are used as
257	>	* placeholders while establishing values in computeIfAbsent and
258	>	* related methods.  The types TreeBin, ForwardingNode, and
259	>	* ReservationNode do not hold normal user keys, values, or
260	>	* hashes, and are readily distinguishable during search etc
261	>	* because they have negative hash fields and null key and value
262	>	* fields. (These special nodes are either uncommon or transient,
263	>	* so the impact of carrying around some unused fields is
264	>	* insignificant.)
265	>	*
266	>	* The table is lazily initialized to a power-of-two size upon the
267	>	* first insertion.  Each bin in the table normally contains a
268	>	* list of Nodes (most often, the list has only zero or one Node).
269	>	* Table accesses require volatile/atomic reads, writes, and
270	>	* CASes.  Because there is no other way to arrange this without
271	>	* adding further indirections, we use intrinsics
272	>	* (sun.misc.Unsafe) operations.
273	>	*
274	>	* We use the top (sign) bit of Node hash fields for control
275	>	* purposes -- it is available anyway because of addressing
276	>	* constraints.  Nodes with negative hash fields are specially
277	>	* handled or ignored in map methods.
278	>	*
279	>	* Insertion (via put or its variants) of the first node in an
280	>	* empty bin is performed by just CASing it to the bin.  This is
281	>	* by far the most common case for put operations under most
282	>	* key/hash distributions.  Other update operations (insert,
283	>	* delete, and replace) require locks.  We do not want to waste
284	>	* the space required to associate a distinct lock object with
285	>	* each bin, so instead use the first node of a bin list itself as
286	>	* a lock. Locking support for these locks relies on builtin
287	>	* "synchronized" monitors.
288	>	*
289	>	* Using the first node of a list as a lock does not by itself
290	>	* suffice though: When a node is locked, any update must first
291	>	* validate that it is still the first node after locking it, and
292	>	* retry if not. Because new nodes are always appended to lists,
293	>	* once a node is first in a bin, it remains first until deleted
294	>	* or the bin becomes invalidated (upon resizing).
295	>	*
296	>	* The main disadvantage of per-bin locks is that other update
297	>	* operations on other nodes in a bin list protected by the same
298	>	* lock can stall, for example when user equals() or mapping
299	>	* functions take a long time.  However, statistically, under
300	>	* random hash codes, this is not a common problem.  Ideally, the
301	>	* frequency of nodes in bins follows a Poisson distribution
302	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
303	>	* parameter of about 0.5 on average, given the resizing threshold
304	>	* of 0.75, although with a large variance because of resizing
305	>	* granularity. Ignoring variance, the expected occurrences of
306	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
307	>	* first values are:
308	>	*
309	>	* 0:    0.60653066
310	>	* 1:    0.30326533
311	>	* 2:    0.07581633
312	>	* 3:    0.01263606
313	>	* 4:    0.00157952
314	>	* 5:    0.00015795
315	>	* 6:    0.00001316
316	>	* 7:    0.00000094
317	>	* 8:    0.00000006
318	>	* more: less than 1 in ten million
319	>	*
320	>	* Lock contention probability for two threads accessing distinct
321	>	* elements is roughly 1 / (8 * #elements) under random hashes.
322	>	*
323	>	* Actual hash code distributions encountered in practice
324	>	* sometimes deviate significantly from uniform randomness.  This
325	>	* includes the case when N > (1<<30), so some keys MUST collide.
326	>	* Similarly for dumb or hostile usages in which multiple keys are
327	>	* designed to have identical hash codes or ones that differs only
328	>	* in masked-out high bits. So we use a secondary strategy that
329	>	* applies when the number of nodes in a bin exceeds a
330	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
331	>	* specialized form of red-black trees), bounding search time to
332	>	* O(log N).  Each search step in a TreeBin is at least twice as
333	>	* slow as in a regular list, but given that N cannot exceed
334	>	* (1<<64) (before running out of addresses) this bounds search
335	>	* steps, lock hold times, etc, to reasonable constants (roughly
336	>	* 100 nodes inspected per operation worst case) so long as keys
337	>	* are Comparable (which is very common -- String, Long, etc).
338	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
339	>	* traversal pointers as regular nodes, so can be traversed in
340	>	* iterators in the same way.
341	>	*
342	>	* The table is resized when occupancy exceeds a percentage
343	>	* threshold (nominally, 0.75, but see below).  Any thread
344	>	* noticing an overfull bin may assist in resizing after the
345	>	* initiating thread allocates and sets up the replacement array.
346	>	* However, rather than stalling, these other threads may proceed
347	>	* with insertions etc.  The use of TreeBins shields us from the
348	>	* worst case effects of overfilling while resizes are in
349	>	* progress.  Resizing proceeds by transferring bins, one by one,
350	>	* from the table to the next table. However, threads claim small
351	>	* blocks of indices to transfer (via field transferIndex) before
352	>	* doing so, reducing contention.  A generation stamp in field
353	>	* sizeCtl ensures that resizings do not overlap. Because we are
354	>	* using power-of-two expansion, the elements from each bin must
355	>	* either stay at same index, or move with a power of two
356	>	* offset. We eliminate unnecessary node creation by catching
357	>	* cases where old nodes can be reused because their next fields
358	>	* won't change.  On average, only about one-sixth of them need
359	>	* cloning when a table doubles. The nodes they replace will be
360	>	* garbage collectable as soon as they are no longer referenced by
361	>	* any reader thread that may be in the midst of concurrently
362	>	* traversing table.  Upon transfer, the old table bin contains
363	>	* only a special forwarding node (with hash field "MOVED") that
364	>	* contains the next table as its key. On encountering a
365	>	* forwarding node, access and update operations restart, using
366	>	* the new table.
367	>	*
368	>	* Each bin transfer requires its bin lock, which can stall
369	>	* waiting for locks while resizing. However, because other
370	>	* threads can join in and help resize rather than contend for
371	>	* locks, average aggregate waits become shorter as resizing
372	>	* progresses.  The transfer operation must also ensure that all
373	>	* accessible bins in both the old and new table are usable by any
374	>	* traversal.  This is arranged in part by proceeding from the
375	>	* last bin (table.length - 1) up towards the first.  Upon seeing
376	>	* a forwarding node, traversals (see class Traverser) arrange to
377	>	* move to the new table without revisiting nodes.  To ensure that
378	>	* no intervening nodes are skipped even when moved out of order,
379	>	* a stack (see class TableStack) is created on first encounter of
380	>	* a forwarding node during a traversal, to maintain its place if
381	>	* later processing the current table. The need for these
382	>	* save/restore mechanics is relatively rare, but when one
383	>	* forwarding node is encountered, typically many more will be.
384	>	* So Traversers use a simple caching scheme to avoid creating so
385	>	* many new TableStack nodes. (Thanks to Peter Levart for
386	>	* suggesting use of a stack here.)
387	>	*
388	>	* The traversal scheme also applies to partial traversals of
389	>	* ranges of bins (via an alternate Traverser constructor)
390	>	* to support partitioned aggregate operations.  Also, read-only
391	>	* operations give up if ever forwarded to a null table, which
392	>	* provides support for shutdown-style clearing, which is also not
393	>	* currently implemented.
394	>	*
395	>	* Lazy table initialization minimizes footprint until first use,
396	>	* and also avoids resizings when the first operation is from a
397	>	* putAll, constructor with map argument, or deserialization.
398	>	* These cases attempt to override the initial capacity settings,
399	>	* but harmlessly fail to take effect in cases of races.
400	>	*
401	>	* The element count is maintained using a specialization of
402	>	* LongAdder. We need to incorporate a specialization rather than
403	>	* just use a LongAdder in order to access implicit
404	>	* contention-sensing that leads to creation of multiple
405	>	* CounterCells.  The counter mechanics avoid contention on
406	>	* updates but can encounter cache thrashing if read too
407	>	* frequently during concurrent access. To avoid reading so often,
408	>	* resizing under contention is attempted only upon adding to a
409	>	* bin already holding two or more nodes. Under uniform hash
410	>	* distributions, the probability of this occurring at threshold
411	>	* is around 13%, meaning that only about 1 in 8 puts check
412	>	* threshold (and after resizing, many fewer do so).
413	>	*
414	>	* TreeBins use a special form of comparison for search and
415	>	* related operations (which is the main reason we cannot use
416	>	* existing collections such as TreeMaps). TreeBins contain
417	>	* Comparable elements, but may contain others, as well as
418	>	* elements that are Comparable but not necessarily Comparable for
419	>	* the same T, so we cannot invoke compareTo among them. To handle
420	>	* this, the tree is ordered primarily by hash value, then by
421	>	* Comparable.compareTo order if applicable.  On lookup at a node,
422	>	* if elements are not comparable or compare as 0 then both left
423	>	* and right children may need to be searched in the case of tied
424	>	* hash values. (This corresponds to the full list search that
425	>	* would be necessary if all elements were non-Comparable and had
426	>	* tied hashes.) On insertion, to keep a total ordering (or as
427	>	* close as is required here) across rebalancings, we compare
428	>	* classes and identityHashCodes as tie-breakers. The red-black
429	>	* balancing code is updated from pre-jdk-collections
430	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
431	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
432	>	* Algorithms" (CLR).
433	>	*
434	>	* TreeBins also require an additional locking mechanism.  While
435	>	* list traversal is always possible by readers even during
436	>	* updates, tree traversal is not, mainly because of tree-rotations
437	>	* that may change the root node and/or its linkages.  TreeBins
438	>	* include a simple read-write lock mechanism parasitic on the
439	>	* main bin-synchronization strategy: Structural adjustments
440	>	* associated with an insertion or removal are already bin-locked
441	>	* (and so cannot conflict with other writers) but must wait for
442	>	* ongoing readers to finish. Since there can be only one such
443	>	* waiter, we use a simple scheme using a single "waiter" field to
444	>	* block writers.  However, readers need never block.  If the root
445	>	* lock is held, they proceed along the slow traversal path (via
446	>	* next-pointers) until the lock becomes available or the list is
447	>	* exhausted, whichever comes first. These cases are not fast, but
448	>	* maximize aggregate expected throughput.
449	>	*
450	>	* Maintaining API and serialization compatibility with previous
451	>	* versions of this class introduces several oddities. Mainly: We
452	>	* leave untouched but unused constructor arguments referring to
453	>	* concurrencyLevel. We accept a loadFactor constructor argument,
454	>	* but apply it only to initial table capacity (which is the only
455	>	* time that we can guarantee to honor it.) We also declare an
456	>	* unused "Segment" class that is instantiated in minimal form
457	>	* only when serializing.
458	>	*
459	>	* Also, solely for compatibility with previous versions of this
460	>	* class, it extends AbstractMap, even though all of its methods
461	>	* are overridden, so it is just useless baggage.
462	>	*
463	>	* This file is organized to make things a little easier to follow
464	>	* while reading than they might otherwise: First the main static
465	>	* declarations and utilities, then fields, then main public
466	>	* methods (with a few factorings of multiple public methods into
467	>	* internal ones), then sizing methods, trees, traversers, and
468	>	* bulk operations.
469		*/
470
471		/* ---------------- Constants -------------- */
472	<
472	>
473	>	/**
474	>	* The largest possible table capacity.  This value must be
475	>	* exactly 1<<30 to stay within Java array allocation and indexing
476	>	* bounds for power of two table sizes, and is further required
477	>	* because the top two bits of 32bit hash fields are used for
478	>	* control purposes.
479	>	*/
480	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
481	>
482	>	/**
483	>	* The default initial table capacity.  Must be a power of 2
484	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
485	>	*/
486	>	private static final int DEFAULT_CAPACITY = 16;
487	>
488	>	/**
489	>	* The largest possible (non-power of two) array size.
490	>	* Needed by toArray and related methods.
491	>	*/
492	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
493	>
494		/**
495	<	* The default initial number of table slots for this table (32).
496	<	* Used when not otherwise specified in constructor.
495	>	* The default concurrency level for this table. Unused but
496	>	* defined for compatibility with previous versions of this class.
497		*/
498	<	static int DEFAULT_INITIAL_CAPACITY = 16;
498	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
499
500		/**
501	<	* The maximum capacity, used if a higher value is implicitly
502	<	* specified by either of the constructors with arguments.  MUST
503	<	* be a power of two <= 1<<30.
501	>	* The load factor for this table. Overrides of this value in
502	>	* constructors affect only the initial table capacity.  The
503	>	* actual floating point value isn't normally used -- it is
504	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
505	>	* the associated resizing threshold.
506		*/
507	<	static final int MAXIMUM_CAPACITY = 1 << 30;
508	<
507	>	private static final float LOAD_FACTOR = 0.75f;
508	>
509	>	/**
510	>	* The bin count threshold for using a tree rather than list for a
511	>	* bin.  Bins are converted to trees when adding an element to a
512	>	* bin with at least this many nodes. The value must be greater
513	>	* than 2, and should be at least 8 to mesh with assumptions in
514	>	* tree removal about conversion back to plain bins upon
515	>	* shrinkage.
516	>	*/
517	>	static final int TREEIFY_THRESHOLD = 8;
518	>
519		/**
520	<	* The default load factor for this table.  Used when not
521	<	* otherwise specified in constructor.
520	>	* The bin count threshold for untreeifying a (split) bin during a
521	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
522	>	* most 6 to mesh with shrinkage detection under removal.
523		*/
524	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
524	>	static final int UNTREEIFY_THRESHOLD = 6;
525
526		/**
527	<	* The default number of concurrency control segments.
528	<	**/
529	<	private static final int DEFAULT_SEGMENTS = 16;
527	>	* The smallest table capacity for which bins may be treeified.
528	>	* (Otherwise the table is resized if too many nodes in a bin.)
529	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
530	>	* conflicts between resizing and treeification thresholds.
531	>	*/
532	>	static final int MIN_TREEIFY_CAPACITY = 64;
533	>
534	>	/**
535	>	* Minimum number of rebinnings per transfer step. Ranges are
536	>	* subdivided to allow multiple resizer threads.  This value
537	>	* serves as a lower bound to avoid resizers encountering
538	>	* excessive memory contention.  The value should be at least
539	>	* DEFAULT_CAPACITY.
540	>	*/
541	>	private static final int MIN_TRANSFER_STRIDE = 16;
542	>
543	>	/**
544	>	* The number of bits used for generation stamp in sizeCtl.
545	>	* Must be at least 6 for 32bit arrays.
546	>	*/
547	>	private static int RESIZE_STAMP_BITS = 16;
548	>
549	>	/**
550	>	* The maximum number of threads that can help resize.
551	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
552	>	*/
553	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
554	>
555	>	/**
556	>	* The bit shift for recording size stamp in sizeCtl.
557	>	*/
558	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
559	>
560	>	/*
561	>	* Encodings for Node hash fields. See above for explanation.
562	>	*/
563	>	static final int MOVED     = -1; // hash for forwarding nodes
564	>	static final int TREEBIN   = -2; // hash for roots of trees
565	>	static final int RESERVED  = -3; // hash for transient reservations
566	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
567	>
568	>	/** Number of CPUS, to place bounds on some sizings */
569	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
570	>
571	>	/** For serialization compatibility. */
572	>	private static final ObjectStreamField[] serialPersistentFields = {
573	>	new ObjectStreamField("segments", Segment[].class),
574	>	new ObjectStreamField("segmentMask", Integer.TYPE),
575	>	new ObjectStreamField("segmentShift", Integer.TYPE)
576	>	};
577	>
578	>	/* ---------------- Nodes -------------- */
579	>
580	>	/**
581	>	* Key-value entry.  This class is never exported out as a
582	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
583	>	* MapEntry below), but can be used for read-only traversals used
584	>	* in bulk tasks.  Subclasses of Node with a negative hash field
585	>	* are special, and contain null keys and values (but are never
586	>	* exported).  Otherwise, keys and vals are never null.
587	>	*/
588	>	static class Node<K,V> implements Map.Entry<K,V> {
589	>	final int hash;
590	>	final K key;
591	>	volatile V val;
592	>	volatile Node<K,V> next;
593	>
594	>	Node(int hash, K key, V val, Node<K,V> next) {
595	>	this.hash = hash;
596	>	this.key = key;
597	>	this.val = val;
598	>	this.next = next;
599	>	}
600	>
601	>	public final K getKey()     { return key; }
602	>	public final V getValue()   { return val; }
603	>	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
604	>	public final String toString() {
605	>	return Helpers.mapEntryToString(key, val);
606	>	}
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	>	* 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 spread(int h) {
656	>	return (h ^ (h >>> 16)) & HASH_BITS;
657	>	}
658	>
659	>	/**
660	>	* Returns a power of two table size for the given desired capacity.
661	>	* See Hackers Delight, sec 3.2
662	>	*/
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	>	* 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	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
698	>	* class), else 0.
699	>	*/
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 lower bits of a
742	<	* key's hash code are used to choose the segment, and the
743	<	* remaining bits are used as the placement hashcode used within
744	<	* the segment.
745	<	**/
746	<	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	<	* Shift value for indexing within segments.
760	<	**/
761	<	private final int segmentShift;
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 segments, each of which is a specialized hash table
769	>	* The next table index (plus one) to split while resizing.
770		*/
771	<	private final Segment<K,V>[] segments;
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
108	–	private transient Set<K> keySet;
109	–	private transient Set/*<Map.Entry<K,V>>*/ entrySet;
110	–	private transient Collection<V> values;
788
789	<	/* ---------------- Small Utilities -------------- */
789	>	/* ---------------- Public operations -------------- */
790
791		/**
792	<	* Return a hash code for non-null Object x.
116	<	* Uses the same hash code spreader as most other j.u hash tables.
792	>	* Creates a new, empty map with the default initial table size (16).
793		*/
794	<	private static int hash(Object x) {
795	<	int h = x.hashCode();
796	<	h += ~(h << 9);
797	<	h ^=  (h >>> 14);
798	<	h +=  (h << 4);
799	<	h ^=  (h >>> 10);
800	<	return h;
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	<	* Check for equality of non-null references x and y.
889	<	**/
890	<	private static boolean eq(Object x, Object y) {
891	<	return x == y || x.equals(y);
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	<	* Return index for hash code h in table of given length.
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	<	private static int indexFor(int h, int length) {
935	<	return h & (length-1);
934	>	public boolean containsKey(Object key) {
935	>	return get(key) != null;
936		}
937
938		/**
939	<	* Return the segment that should be used for key with given hash
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	<	private Segment<K,V> segmentFor(int hash) {
949	<	return segments[hash & segmentMask];
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	<	* Strip the segment index from hash code to use as a per-segment hash.
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	<	private int segmentHashFor(int hash) {
977	<	return hash >>> segmentShift;
976	>	public V put(K key, V value) {
977	>	return putVal(key, value, false);
978		}
979
980	<	/* ---------------- Inner Classes -------------- */
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	<	* Segments are specialized versions of hash tables.  This
1049	<	* subclasses from ReentrantLock opportunistically, just to
1050	<	* simplify some locking and avoid separate construction.
1051	<	**/
1052	<	private final static class Segment<K,V> extends ReentrantLock implements Serializable {
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	>	* 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	>	* 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	>	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	>	/**
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	>	/**
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	>	* 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	>	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	>	* 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	>	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	>	/**
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	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1379	>	streamFields.put("segments", segments);
1380	>	streamFields.put("segmentShift", segmentShift);
1381	>	streamFields.put("segmentMask", segmentMask);
1382	>	s.writeFields();
1383	>
1384	>	Node<K,V>[] t;
1385	>	if ((t = table) != null) {
1386	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1387	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1388	>	s.writeObject(p.key);
1389	>	s.writeObject(p.val);
1390	>	}
1391	>	}
1392	>	s.writeObject(null);
1393	>	s.writeObject(null);
1394	>	segments = null; // throw away
1395	>	}
1396	>
1397	>	/**
1398	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1399	>	* @param s the stream
1400	>	* @throws ClassNotFoundException if the class of a serialized object
1401	>	*         could not be found
1402	>	* @throws java.io.IOException if an I/O error occurs
1403	>	*/
1404	>	private void readObject(java.io.ObjectInputStream s)
1405	>	throws java.io.IOException, ClassNotFoundException {
1406		/*
1407	<	* Segments maintain a table of entry lists that are ALWAYS
1408	<	* kept in a consistent state, so can be read without locking.
1409	<	* Next fields of nodes are immutable (final).  All list
1410	<	* additions are performed at the front of each bin. This
1411	<	* makes it easy to check changes, and also fast to traverse.
169	<	* When nodes would otherwise be changed, new nodes are
170	<	* created to replace them. This works well for hash tables
171	<	* since the bin lists tend to be short. (The average length
172	<	* is less than two for the default load factor threshold.)
173	<	*
174	<	* Read operations can thus proceed without locking, but rely
175	<	* on a memory barrier to ensure that completed write
176	<	* operations performed by other threads are
177	<	* noticed. Conveniently, the "count" field, tracking the
178	<	* number of elements, can also serve as the volatile variable
179	<	* providing proper read/write barriers. This is convenient
180	<	* because this field needs to be read in many read operations
181	<	* anyway. The use of volatiles for this purpose is only
182	<	* guaranteed to work in accord with reuirements in
183	<	* multithreaded environments when run on JVMs conforming to
184	<	* the clarified JSR133 memory model specification.  This true
185	<	* for hotspot as of release 1.4.
186	<	*
187	<	* Implementors note. The basic rules for all this are:
188	<	*
189	<	*   - All unsynchronized read operations must first read the
190	<	*     "count" field, and should not look at table entries if
191	<	*     it is 0.
192	<	*
193	<	*   - All synchronized write operations should write to
194	<	*     the "count" field after updating. The operations must not
195	<	*     take any action that could even momentarily cause
196	<	*     a concurrent read operation to see inconsistent
197	<	*     data. This is made easier by the nature of the read
198	<	*     operations in Map. For example, no operation
199	<	*     can reveal that the table has grown but the threshold
200	<	*     has not yet been updated, so there are no atomicity
201	<	*     requirements for this with respect to reads.
202	<	*
203	<	* As a guide, all critical volatile reads and writes are marked
204	<	* in code comments.
1407	>	* To improve performance in typical cases, we create nodes
1408	>	* while reading, then place in table once size is known.
1409	>	* However, we must also validate uniqueness and deal with
1410	>	* overpopulated bins while doing so, which requires
1411	>	* specialized versions of putVal mechanics.
1412		*/
1413	<
1413	>	sizeCtl = -1; // force exclusion for table construction
1414	>	s.defaultReadObject();
1415	>	long size = 0L;
1416	>	Node<K,V> p = null;
1417	>	for (;;) {
1418	>	@SuppressWarnings("unchecked")
1419	>	K k = (K) s.readObject();
1420	>	@SuppressWarnings("unchecked")
1421	>	V v = (V) s.readObject();
1422	>	if (k != null && v != null) {
1423	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1424	>	++size;
1425	>	}
1426	>	else
1427	>	break;
1428	>	}
1429	>	if (size == 0L)
1430	>	sizeCtl = 0;
1431	>	else {
1432	>	int n;
1433	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1434	>	n = MAXIMUM_CAPACITY;
1435	>	else {
1436	>	int sz = (int)size;
1437	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1438	>	}
1439	>	@SuppressWarnings("unchecked")
1440	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1441	>	int mask = n - 1;
1442	>	long added = 0L;
1443	>	while (p != null) {
1444	>	boolean insertAtFront;
1445	>	Node<K,V> next = p.next, first;
1446	>	int h = p.hash, j = h & mask;
1447	>	if ((first = tabAt(tab, j)) == null)
1448	>	insertAtFront = true;
1449	>	else {
1450	>	K k = p.key;
1451	>	if (first.hash < 0) {
1452	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1453	>	if (t.putTreeVal(h, k, p.val) == null)
1454	>	++added;
1455	>	insertAtFront = false;
1456	>	}
1457	>	else {
1458	>	int binCount = 0;
1459	>	insertAtFront = true;
1460	>	Node<K,V> q; K qk;
1461	>	for (q = first; q != null; q = q.next) {
1462	>	if (q.hash == h &&
1463	>	((qk = q.key) == k ||
1464	>	(qk != null && k.equals(qk)))) {
1465	>	insertAtFront = false;
1466	>	break;
1467	>	}
1468	>	++binCount;
1469	>	}
1470	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1471	>	insertAtFront = false;
1472	>	++added;
1473	>	p.next = first;
1474	>	TreeNode<K,V> hd = null, tl = null;
1475	>	for (q = p; q != null; q = q.next) {
1476	>	TreeNode<K,V> t = new TreeNode<K,V>
1477	>	(q.hash, q.key, q.val, null, null);
1478	>	if ((t.prev = tl) == null)
1479	>	hd = t;
1480	>	else
1481	>	tl.next = t;
1482	>	tl = t;
1483	>	}
1484	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1485	>	}
1486	>	}
1487	>	}
1488	>	if (insertAtFront) {
1489	>	++added;
1490	>	p.next = first;
1491	>	setTabAt(tab, j, p);
1492	>	}
1493	>	p = next;
1494	>	}
1495	>	table = tab;
1496	>	sizeCtl = n - (n >>> 2);
1497	>	baseCount = added;
1498	>	}
1499	>	}
1500	>
1501	>	// ConcurrentMap methods
1502	>
1503	>	/**
1504	>	* {@inheritDoc}
1505	>	*
1506	>	* @return the previous value associated with the specified key,
1507	>	*         or {@code null} if there was no mapping for the key
1508	>	* @throws NullPointerException if the specified key or value is null
1509	>	*/
1510	>	public V putIfAbsent(K key, V value) {
1511	>	return putVal(key, value, true);
1512	>	}
1513	>
1514	>	/**
1515	>	* {@inheritDoc}
1516	>	*
1517	>	* @throws NullPointerException if the specified key is null
1518	>	*/
1519	>	public boolean remove(Object key, Object value) {
1520	>	if (key == null)
1521	>	throw new NullPointerException();
1522	>	return value != null && replaceNode(key, null, value) != null;
1523	>	}
1524	>
1525	>	/**
1526	>	* {@inheritDoc}
1527	>	*
1528	>	* @throws NullPointerException if any of the arguments are null
1529	>	*/
1530	>	public boolean replace(K key, V oldValue, V newValue) {
1531	>	if (key == null || oldValue == null || newValue == null)
1532	>	throw new NullPointerException();
1533	>	return replaceNode(key, newValue, oldValue) != null;
1534	>	}
1535	>
1536	>	/**
1537	>	* {@inheritDoc}
1538	>	*
1539	>	* @return the previous value associated with the specified key,
1540	>	*         or {@code null} if there was no mapping for the key
1541	>	* @throws NullPointerException if the specified key or value is null
1542	>	*/
1543	>	public V replace(K key, V value) {
1544	>	if (key == null || value == null)
1545	>	throw new NullPointerException();
1546	>	return replaceNode(key, value, null);
1547	>	}
1548	>
1549	>	// Overrides of JDK8+ Map extension method defaults
1550	>
1551	>	/**
1552	>	* Returns the value to which the specified key is mapped, or the
1553	>	* given default value if this map contains no mapping for the
1554	>	* key.
1555	>	*
1556	>	* @param key the key whose associated value is to be returned
1557	>	* @param defaultValue the value to return if this map contains
1558	>	* no mapping for the given key
1559	>	* @return the mapping for the key, if present; else the default value
1560	>	* @throws NullPointerException if the specified key is null
1561	>	*/
1562	>	public V getOrDefault(Object key, V defaultValue) {
1563	>	V v;
1564	>	return (v = get(key)) == null ? defaultValue : v;
1565	>	}
1566	>
1567	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1568	>	if (action == null) throw new NullPointerException();
1569	>	Node<K,V>[] t;
1570	>	if ((t = table) != null) {
1571	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1572	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1573	>	action.accept(p.key, p.val);
1574	>	}
1575	>	}
1576	>	}
1577	>
1578	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1579	>	if (function == null) throw new NullPointerException();
1580	>	Node<K,V>[] t;
1581	>	if ((t = table) != null) {
1582	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1583	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1584	>	V oldValue = p.val;
1585	>	for (K key = p.key;;) {
1586	>	V newValue = function.apply(key, oldValue);
1587	>	if (newValue == null)
1588	>	throw new NullPointerException();
1589	>	if (replaceNode(key, newValue, oldValue) != null ||
1590	>	(oldValue = get(key)) == null)
1591	>	break;
1592	>	}
1593	>	}
1594	>	}
1595	>	}
1596	>
1597	>	/**
1598	>	* Helper method for EntrySetView.removeIf
1599	>	*/
1600	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1601	>	if (function == null) throw new NullPointerException();
1602	>	Node<K,V>[] t;
1603	>	boolean removed = false;
1604	>	if ((t = table) != null) {
1605	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1606	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1607	>	K k = p.key;
1608	>	V v = p.val;
1609	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1610	>	if (function.test(e) && replaceNode(k, null, v) != null)
1611	>	removed = true;
1612	>	}
1613	>	}
1614	>	return removed;
1615	>	}
1616	>
1617	>	/**
1618	>	* Helper method for ValuesView.removeIf
1619	>	*/
1620	>	boolean removeValueIf(Predicate<? super V> function) {
1621	>	if (function == null) throw new NullPointerException();
1622	>	Node<K,V>[] t;
1623	>	boolean removed = false;
1624	>	if ((t = table) != null) {
1625	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1626	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1627	>	K k = p.key;
1628	>	V v = p.val;
1629	>	if (function.test(v) && replaceNode(k, null, v) != null)
1630	>	removed = true;
1631	>	}
1632	>	}
1633	>	return removed;
1634	>	}
1635	>
1636	>	/**
1637	>	* If the specified key is not already associated with a value,
1638	>	* attempts to compute its value using the given mapping function
1639	>	* and enters it into this map unless {@code null}.  The entire
1640	>	* method invocation is performed atomically, so the function is
1641	>	* applied at most once per key.  Some attempted update operations
1642	>	* on this map by other threads may be blocked while computation
1643	>	* is in progress, so the computation should be short and simple,
1644	>	* and must not attempt to update any other mappings of this map.
1645	>	*
1646	>	* @param key key with which the specified value is to be associated
1647	>	* @param mappingFunction the function to compute a value
1648	>	* @return the current (existing or computed) value associated with
1649	>	*         the specified key, or null if the computed value is null
1650	>	* @throws NullPointerException if the specified key or mappingFunction
1651	>	*         is null
1652	>	* @throws IllegalStateException if the computation detectably
1653	>	*         attempts a recursive update to this map that would
1654	>	*         otherwise never complete
1655	>	* @throws RuntimeException or Error if the mappingFunction does so,
1656	>	*         in which case the mapping is left unestablished
1657	>	*/
1658	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1659	>	if (key == null || mappingFunction == null)
1660	>	throw new NullPointerException();
1661	>	int h = spread(key.hashCode());
1662	>	V val = null;
1663	>	int binCount = 0;
1664	>	for (Node<K,V>[] tab = table;;) {
1665	>	Node<K,V> f; int n, i, fh;
1666	>	if (tab == null || (n = tab.length) == 0)
1667	>	tab = initTable();
1668	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1669	>	Node<K,V> r = new ReservationNode<K,V>();
1670	>	synchronized (r) {
1671	>	if (casTabAt(tab, i, null, r)) {
1672	>	binCount = 1;
1673	>	Node<K,V> node = null;
1674	>	try {
1675	>	if ((val = mappingFunction.apply(key)) != null)
1676	>	node = new Node<K,V>(h, key, val, null);
1677	>	} finally {
1678	>	setTabAt(tab, i, node);
1679	>	}
1680	>	}
1681	>	}
1682	>	if (binCount != 0)
1683	>	break;
1684	>	}
1685	>	else if ((fh = f.hash) == MOVED)
1686	>	tab = helpTransfer(tab, f);
1687	>	else {
1688	>	boolean added = false;
1689	>	synchronized (f) {
1690	>	if (tabAt(tab, i) == f) {
1691	>	if (fh >= 0) {
1692	>	binCount = 1;
1693	>	for (Node<K,V> e = f;; ++binCount) {
1694	>	K ek;
1695	>	if (e.hash == h &&
1696	>	((ek = e.key) == key ||
1697	>	(ek != null && key.equals(ek)))) {
1698	>	val = e.val;
1699	>	break;
1700	>	}
1701	>	Node<K,V> pred = e;
1702	>	if ((e = e.next) == null) {
1703	>	if ((val = mappingFunction.apply(key)) != null) {
1704	>	if (pred.next != null)
1705	>	throw new IllegalStateException("Recursive update");
1706	>	added = true;
1707	>	pred.next = new Node<K,V>(h, key, val, null);
1708	>	}
1709	>	break;
1710	>	}
1711	>	}
1712	>	}
1713	>	else if (f instanceof TreeBin) {
1714	>	binCount = 2;
1715	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1716	>	TreeNode<K,V> r, p;
1717	>	if ((r = t.root) != null &&
1718	>	(p = r.findTreeNode(h, key, null)) != null)
1719	>	val = p.val;
1720	>	else if ((val = mappingFunction.apply(key)) != null) {
1721	>	added = true;
1722	>	t.putTreeVal(h, key, val);
1723	>	}
1724	>	}
1725	>	else if (f instanceof ReservationNode)
1726	>	throw new IllegalStateException("Recursive update");
1727	>	}
1728	>	}
1729	>	if (binCount != 0) {
1730	>	if (binCount >= TREEIFY_THRESHOLD)
1731	>	treeifyBin(tab, i);
1732	>	if (!added)
1733	>	return val;
1734	>	break;
1735	>	}
1736	>	}
1737	>	}
1738	>	if (val != null)
1739	>	addCount(1L, binCount);
1740	>	return val;
1741	>	}
1742	>
1743	>	/**
1744	>	* If the value for the specified key is present, attempts to
1745	>	* compute a new mapping given the key and its current mapped
1746	>	* value.  The entire method invocation is performed atomically.
1747	>	* Some attempted update operations on this map by other threads
1748	>	* may be blocked while computation is in progress, so the
1749	>	* computation should be short and simple, and must not attempt to
1750	>	* update any other mappings of this map.
1751	>	*
1752	>	* @param key key with which a value may be associated
1753	>	* @param remappingFunction the function to compute a value
1754	>	* @return the new value associated with the specified key, or null if none
1755	>	* @throws NullPointerException if the specified key or remappingFunction
1756	>	*         is null
1757	>	* @throws IllegalStateException if the computation detectably
1758	>	*         attempts a recursive update to this map that would
1759	>	*         otherwise never complete
1760	>	* @throws RuntimeException or Error if the remappingFunction does so,
1761	>	*         in which case the mapping is unchanged
1762	>	*/
1763	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1764	>	if (key == null || remappingFunction == null)
1765	>	throw new NullPointerException();
1766	>	int h = spread(key.hashCode());
1767	>	V val = null;
1768	>	int delta = 0;
1769	>	int binCount = 0;
1770	>	for (Node<K,V>[] tab = table;;) {
1771	>	Node<K,V> f; int n, i, fh;
1772	>	if (tab == null || (n = tab.length) == 0)
1773	>	tab = initTable();
1774	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1775	>	break;
1776	>	else if ((fh = f.hash) == MOVED)
1777	>	tab = helpTransfer(tab, f);
1778	>	else {
1779	>	synchronized (f) {
1780	>	if (tabAt(tab, i) == f) {
1781	>	if (fh >= 0) {
1782	>	binCount = 1;
1783	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1784	>	K ek;
1785	>	if (e.hash == h &&
1786	>	((ek = e.key) == key ||
1787	>	(ek != null && key.equals(ek)))) {
1788	>	val = remappingFunction.apply(key, e.val);
1789	>	if (val != null)
1790	>	e.val = val;
1791	>	else {
1792	>	delta = -1;
1793	>	Node<K,V> en = e.next;
1794	>	if (pred != null)
1795	>	pred.next = en;
1796	>	else
1797	>	setTabAt(tab, i, en);
1798	>	}
1799	>	break;
1800	>	}
1801	>	pred = e;
1802	>	if ((e = e.next) == null)
1803	>	break;
1804	>	}
1805	>	}
1806	>	else if (f instanceof TreeBin) {
1807	>	binCount = 2;
1808	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1809	>	TreeNode<K,V> r, p;
1810	>	if ((r = t.root) != null &&
1811	>	(p = r.findTreeNode(h, key, null)) != null) {
1812	>	val = remappingFunction.apply(key, p.val);
1813	>	if (val != null)
1814	>	p.val = val;
1815	>	else {
1816	>	delta = -1;
1817	>	if (t.removeTreeNode(p))
1818	>	setTabAt(tab, i, untreeify(t.first));
1819	>	}
1820	>	}
1821	>	}
1822	>	else if (f instanceof ReservationNode)
1823	>	throw new IllegalStateException("Recursive update");
1824	>	}
1825	>	}
1826	>	if (binCount != 0)
1827	>	break;
1828	>	}
1829	>	}
1830	>	if (delta != 0)
1831	>	addCount((long)delta, binCount);
1832	>	return val;
1833	>	}
1834	>
1835	>	/**
1836	>	* Attempts to compute a mapping for the specified key and its
1837	>	* current mapped value (or {@code null} if there is no current
1838	>	* mapping). The entire method invocation is performed atomically.
1839	>	* Some attempted update operations on this map by other threads
1840	>	* may be blocked while computation is in progress, so the
1841	>	* computation should be short and simple, and must not attempt to
1842	>	* update any other mappings of this Map.
1843	>	*
1844	>	* @param key key with which the specified value is to be associated
1845	>	* @param remappingFunction the function to compute a value
1846	>	* @return the new value associated with the specified key, or null if none
1847	>	* @throws NullPointerException if the specified key or remappingFunction
1848	>	*         is null
1849	>	* @throws IllegalStateException if the computation detectably
1850	>	*         attempts a recursive update to this map that would
1851	>	*         otherwise never complete
1852	>	* @throws RuntimeException or Error if the remappingFunction does so,
1853	>	*         in which case the mapping is unchanged
1854	>	*/
1855	>	public V compute(K key,
1856	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1857	>	if (key == null || remappingFunction == null)
1858	>	throw new NullPointerException();
1859	>	int h = spread(key.hashCode());
1860	>	V val = null;
1861	>	int delta = 0;
1862	>	int binCount = 0;
1863	>	for (Node<K,V>[] tab = table;;) {
1864	>	Node<K,V> f; int n, i, fh;
1865	>	if (tab == null || (n = tab.length) == 0)
1866	>	tab = initTable();
1867	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1868	>	Node<K,V> r = new ReservationNode<K,V>();
1869	>	synchronized (r) {
1870	>	if (casTabAt(tab, i, null, r)) {
1871	>	binCount = 1;
1872	>	Node<K,V> node = null;
1873	>	try {
1874	>	if ((val = remappingFunction.apply(key, null)) != null) {
1875	>	delta = 1;
1876	>	node = new Node<K,V>(h, key, val, null);
1877	>	}
1878	>	} finally {
1879	>	setTabAt(tab, i, node);
1880	>	}
1881	>	}
1882	>	}
1883	>	if (binCount != 0)
1884	>	break;
1885	>	}
1886	>	else if ((fh = f.hash) == MOVED)
1887	>	tab = helpTransfer(tab, f);
1888	>	else {
1889	>	synchronized (f) {
1890	>	if (tabAt(tab, i) == f) {
1891	>	if (fh >= 0) {
1892	>	binCount = 1;
1893	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1894	>	K ek;
1895	>	if (e.hash == h &&
1896	>	((ek = e.key) == key ||
1897	>	(ek != null && key.equals(ek)))) {
1898	>	val = remappingFunction.apply(key, e.val);
1899	>	if (val != null)
1900	>	e.val = val;
1901	>	else {
1902	>	delta = -1;
1903	>	Node<K,V> en = e.next;
1904	>	if (pred != null)
1905	>	pred.next = en;
1906	>	else
1907	>	setTabAt(tab, i, en);
1908	>	}
1909	>	break;
1910	>	}
1911	>	pred = e;
1912	>	if ((e = e.next) == null) {
1913	>	val = remappingFunction.apply(key, null);
1914	>	if (val != null) {
1915	>	if (pred.next != null)
1916	>	throw new IllegalStateException("Recursive update");
1917	>	delta = 1;
1918	>	pred.next =
1919	>	new Node<K,V>(h, key, val, null);
1920	>	}
1921	>	break;
1922	>	}
1923	>	}
1924	>	}
1925	>	else if (f instanceof TreeBin) {
1926	>	binCount = 1;
1927	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1928	>	TreeNode<K,V> r, p;
1929	>	if ((r = t.root) != null)
1930	>	p = r.findTreeNode(h, key, null);
1931	>	else
1932	>	p = null;
1933	>	V pv = (p == null) ? null : p.val;
1934	>	val = remappingFunction.apply(key, pv);
1935	>	if (val != null) {
1936	>	if (p != null)
1937	>	p.val = val;
1938	>	else {
1939	>	delta = 1;
1940	>	t.putTreeVal(h, key, val);
1941	>	}
1942	>	}
1943	>	else if (p != null) {
1944	>	delta = -1;
1945	>	if (t.removeTreeNode(p))
1946	>	setTabAt(tab, i, untreeify(t.first));
1947	>	}
1948	>	}
1949	>	else if (f instanceof ReservationNode)
1950	>	throw new IllegalStateException("Recursive update");
1951	>	}
1952	>	}
1953	>	if (binCount != 0) {
1954	>	if (binCount >= TREEIFY_THRESHOLD)
1955	>	treeifyBin(tab, i);
1956	>	break;
1957	>	}
1958	>	}
1959	>	}
1960	>	if (delta != 0)
1961	>	addCount((long)delta, binCount);
1962	>	return val;
1963	>	}
1964	>
1965	>	/**
1966	>	* If the specified key is not already associated with a
1967	>	* (non-null) value, associates it with the given value.
1968	>	* Otherwise, replaces the value with the results of the given
1969	>	* remapping function, or removes if {@code null}. The entire
1970	>	* method invocation is performed atomically.  Some attempted
1971	>	* update operations on this map by other threads may be blocked
1972	>	* while computation is in progress, so the computation should be
1973	>	* short and simple, and must not attempt to update any other
1974	>	* mappings of this Map.
1975	>	*
1976	>	* @param key key with which the specified value is to be associated
1977	>	* @param value the value to use if absent
1978	>	* @param remappingFunction the function to recompute a value if present
1979	>	* @return the new value associated with the specified key, or null if none
1980	>	* @throws NullPointerException if the specified key or the
1981	>	*         remappingFunction is null
1982	>	* @throws RuntimeException or Error if the remappingFunction does so,
1983	>	*         in which case the mapping is unchanged
1984	>	*/
1985	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1986	>	if (key == null || value == null || remappingFunction == null)
1987	>	throw new NullPointerException();
1988	>	int h = spread(key.hashCode());
1989	>	V val = null;
1990	>	int delta = 0;
1991	>	int binCount = 0;
1992	>	for (Node<K,V>[] tab = table;;) {
1993	>	Node<K,V> f; int n, i, fh;
1994	>	if (tab == null || (n = tab.length) == 0)
1995	>	tab = initTable();
1996	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1997	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1998	>	delta = 1;
1999	>	val = value;
2000	>	break;
2001	>	}
2002	>	}
2003	>	else if ((fh = f.hash) == MOVED)
2004	>	tab = helpTransfer(tab, f);
2005	>	else {
2006	>	synchronized (f) {
2007	>	if (tabAt(tab, i) == f) {
2008	>	if (fh >= 0) {
2009	>	binCount = 1;
2010	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2011	>	K ek;
2012	>	if (e.hash == h &&
2013	>	((ek = e.key) == key ||
2014	>	(ek != null && key.equals(ek)))) {
2015	>	val = remappingFunction.apply(e.val, value);
2016	>	if (val != null)
2017	>	e.val = val;
2018	>	else {
2019	>	delta = -1;
2020	>	Node<K,V> en = e.next;
2021	>	if (pred != null)
2022	>	pred.next = en;
2023	>	else
2024	>	setTabAt(tab, i, en);
2025	>	}
2026	>	break;
2027	>	}
2028	>	pred = e;
2029	>	if ((e = e.next) == null) {
2030	>	delta = 1;
2031	>	val = value;
2032	>	pred.next =
2033	>	new Node<K,V>(h, key, val, null);
2034	>	break;
2035	>	}
2036	>	}
2037	>	}
2038	>	else if (f instanceof TreeBin) {
2039	>	binCount = 2;
2040	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2041	>	TreeNode<K,V> r = t.root;
2042	>	TreeNode<K,V> p = (r == null) ? null :
2043	>	r.findTreeNode(h, key, null);
2044	>	val = (p == null) ? value :
2045	>	remappingFunction.apply(p.val, value);
2046	>	if (val != null) {
2047	>	if (p != null)
2048	>	p.val = val;
2049	>	else {
2050	>	delta = 1;
2051	>	t.putTreeVal(h, key, val);
2052	>	}
2053	>	}
2054	>	else if (p != null) {
2055	>	delta = -1;
2056	>	if (t.removeTreeNode(p))
2057	>	setTabAt(tab, i, untreeify(t.first));
2058	>	}
2059	>	}
2060	>	else if (f instanceof ReservationNode)
2061	>	throw new IllegalStateException("Recursive update");
2062	>	}
2063	>	}
2064	>	if (binCount != 0) {
2065	>	if (binCount >= TREEIFY_THRESHOLD)
2066	>	treeifyBin(tab, i);
2067	>	break;
2068	>	}
2069	>	}
2070	>	}
2071	>	if (delta != 0)
2072	>	addCount((long)delta, binCount);
2073	>	return val;
2074	>	}
2075	>
2076	>	// Hashtable legacy methods
2077	>
2078	>	/**
2079	>	* Tests if some key maps into the specified value in this table.
2080	>	*
2081	>	* <p>Note that this method is identical in functionality to
2082	>	* {@link #containsValue(Object)}, and exists solely to ensure
2083	>	* full compatibility with class {@link java.util.Hashtable},
2084	>	* which supported this method prior to introduction of the Java
2085	>	* Collections Framework.
2086	>	*
2087	>	* @param  value a value to search for
2088	>	* @return {@code true} if and only if some key maps to the
2089	>	*         {@code value} argument in this table as
2090	>	*         determined by the {@code equals} method;
2091	>	*         {@code false} otherwise
2092	>	* @throws NullPointerException if the specified value is null
2093	>	*/
2094	>	public boolean contains(Object value) {
2095	>	return containsValue(value);
2096	>	}
2097	>
2098	>	/**
2099	>	* Returns an enumeration of the keys in this table.
2100	>	*
2101	>	* @return an enumeration of the keys in this table
2102	>	* @see #keySet()
2103	>	*/
2104	>	public Enumeration<K> keys() {
2105	>	Node<K,V>[] t;
2106	>	int f = (t = table) == null ? 0 : t.length;
2107	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2108	>	}
2109	>
2110	>	/**
2111	>	* Returns an enumeration of the values in this table.
2112	>	*
2113	>	* @return an enumeration of the values in this table
2114	>	* @see #values()
2115	>	*/
2116	>	public Enumeration<V> elements() {
2117	>	Node<K,V>[] t;
2118	>	int f = (t = table) == null ? 0 : t.length;
2119	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2120	>	}
2121	>
2122	>	// ConcurrentHashMap-only methods
2123	>
2124	>	/**
2125	>	* Returns the number of mappings. This method should be used
2126	>	* instead of {@link #size} because a ConcurrentHashMap may
2127	>	* contain more mappings than can be represented as an int. The
2128	>	* value returned is an estimate; the actual count may differ if
2129	>	* there are concurrent insertions or removals.
2130	>	*
2131	>	* @return the number of mappings
2132	>	* @since 1.8
2133	>	*/
2134	>	public long mappingCount() {
2135	>	long n = sumCount();
2136	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2137	>	}
2138	>
2139	>	/**
2140	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2141	>	* from the given type to {@code Boolean.TRUE}.
2142	>	*
2143	>	* @param <K> the element type of the returned set
2144	>	* @return the new set
2145	>	* @since 1.8
2146	>	*/
2147	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2148	>	return new KeySetView<K,Boolean>
2149	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2150	>	}
2151	>
2152	>	/**
2153	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2154	>	* from the given type to {@code Boolean.TRUE}.
2155	>	*
2156	>	* @param initialCapacity The implementation performs internal
2157	>	* sizing to accommodate this many elements.
2158	>	* @param <K> the element type of the returned set
2159	>	* @return the new set
2160	>	* @throws IllegalArgumentException if the initial capacity of
2161	>	* elements is negative
2162	>	* @since 1.8
2163	>	*/
2164	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2165	>	return new KeySetView<K,Boolean>
2166	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2167	>	}
2168	>
2169	>	/**
2170	>	* Returns a {@link Set} view of the keys in this map, using the
2171	>	* given common mapped value for any additions (i.e., {@link
2172	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2173	>	* This is of course only appropriate if it is acceptable to use
2174	>	* the same value for all additions from this view.
2175	>	*
2176	>	* @param mappedValue the mapped value to use for any additions
2177	>	* @return the set view
2178	>	* @throws NullPointerException if the mappedValue is null
2179	>	*/
2180	>	public KeySetView<K,V> keySet(V mappedValue) {
2181	>	if (mappedValue == null)
2182	>	throw new NullPointerException();
2183	>	return new KeySetView<K,V>(this, mappedValue);
2184	>	}
2185	>
2186	>	/* ---------------- Special Nodes -------------- */
2187	>
2188	>	/**
2189	>	* A node inserted at head of bins during transfer operations.
2190	>	*/
2191	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2192	>	final Node<K,V>[] nextTable;
2193	>	ForwardingNode(Node<K,V>[] tab) {
2194	>	super(MOVED, null, null, null);
2195	>	this.nextTable = tab;
2196	>	}
2197	>
2198	>	Node<K,V> find(int h, Object k) {
2199	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2200	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2201	>	Node<K,V> e; int n;
2202	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2203	>	(e = tabAt(tab, (n - 1) & h)) == null)
2204	>	return null;
2205	>	for (;;) {
2206	>	int eh; K ek;
2207	>	if ((eh = e.hash) == h &&
2208	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2209	>	return e;
2210	>	if (eh < 0) {
2211	>	if (e instanceof ForwardingNode) {
2212	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2213	>	continue outer;
2214	>	}
2215	>	else
2216	>	return e.find(h, k);
2217	>	}
2218	>	if ((e = e.next) == null)
2219	>	return null;
2220	>	}
2221	>	}
2222	>	}
2223	>	}
2224	>
2225	>	/**
2226	>	* A place-holder node used in computeIfAbsent and compute
2227	>	*/
2228	>	static final class ReservationNode<K,V> extends Node<K,V> {
2229	>	ReservationNode() {
2230	>	super(RESERVED, null, null, null);
2231	>	}
2232	>
2233	>	Node<K,V> find(int h, Object k) {
2234	>	return null;
2235	>	}
2236	>	}
2237	>
2238	>	/* ---------------- Table Initialization and Resizing -------------- */
2239	>
2240	>	/**
2241	>	* Returns the stamp bits for resizing a table of size n.
2242	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2243	>	*/
2244	>	static final int resizeStamp(int n) {
2245	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2246	>	}
2247	>
2248	>	/**
2249	>	* Initializes table, using the size recorded in sizeCtl.
2250	>	*/
2251	>	private final Node<K,V>[] initTable() {
2252	>	Node<K,V>[] tab; int sc;
2253	>	while ((tab = table) == null || tab.length == 0) {
2254	>	if ((sc = sizeCtl) < 0)
2255	>	Thread.yield(); // lost initialization race; just spin
2256	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2257	>	try {
2258	>	if ((tab = table) == null || tab.length == 0) {
2259	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2260	>	@SuppressWarnings("unchecked")
2261	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2262	>	table = tab = nt;
2263	>	sc = n - (n >>> 2);
2264	>	}
2265	>	} finally {
2266	>	sizeCtl = sc;
2267	>	}
2268	>	break;
2269	>	}
2270	>	}
2271	>	return tab;
2272	>	}
2273	>
2274	>	/**
2275	>	* Adds to count, and if table is too small and not already
2276	>	* resizing, initiates transfer. If already resizing, helps
2277	>	* perform transfer if work is available.  Rechecks occupancy
2278	>	* after a transfer to see if another resize is already needed
2279	>	* because resizings are lagging additions.
2280	>	*
2281	>	* @param x the count to add
2282	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2283	>	*/
2284	>	private final void addCount(long x, int check) {
2285	>	CounterCell[] as; long b, s;
2286	>	if ((as = counterCells) != null ||
2287	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2288	>	CounterCell a; long v; int m;
2289	>	boolean uncontended = true;
2290	>	if (as == null || (m = as.length - 1) < 0 ||
2291	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2292	>	!(uncontended =
2293	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2294	>	fullAddCount(x, uncontended);
2295	>	return;
2296	>	}
2297	>	if (check <= 1)
2298	>	return;
2299	>	s = sumCount();
2300	>	}
2301	>	if (check >= 0) {
2302	>	Node<K,V>[] tab, nt; int n, sc;
2303	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2304	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2305	>	int rs = resizeStamp(n);
2306	>	if (sc < 0) {
2307	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2308	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2309	>	transferIndex <= 0)
2310	>	break;
2311	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2312	>	transfer(tab, nt);
2313	>	}
2314	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2315	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2316	>	transfer(tab, null);
2317	>	s = sumCount();
2318	>	}
2319	>	}
2320	>	}
2321	>
2322	>	/**
2323	>	* Helps transfer if a resize is in progress.
2324	>	*/
2325	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2326	>	Node<K,V>[] nextTab; int sc;
2327	>	if (tab != null && (f instanceof ForwardingNode) &&
2328	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2329	>	int rs = resizeStamp(tab.length);
2330	>	while (nextTab == nextTable && table == tab &&
2331	>	(sc = sizeCtl) < 0) {
2332	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2333	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2334	>	break;
2335	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2336	>	transfer(tab, nextTab);
2337	>	break;
2338	>	}
2339	>	}
2340	>	return nextTab;
2341	>	}
2342	>	return table;
2343	>	}
2344	>
2345	>	/**
2346	>	* Tries to presize table to accommodate the given number of elements.
2347	>	*
2348	>	* @param size number of elements (doesn't need to be perfectly accurate)
2349	>	*/
2350	>	private final void tryPresize(int size) {
2351	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2352	>	tableSizeFor(size + (size >>> 1) + 1);
2353	>	int sc;
2354	>	while ((sc = sizeCtl) >= 0) {
2355	>	Node<K,V>[] tab = table; int n;
2356	>	if (tab == null || (n = tab.length) == 0) {
2357	>	n = (sc > c) ? sc : c;
2358	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2359	>	try {
2360	>	if (table == tab) {
2361	>	@SuppressWarnings("unchecked")
2362	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2363	>	table = nt;
2364	>	sc = n - (n >>> 2);
2365	>	}
2366	>	} finally {
2367	>	sizeCtl = sc;
2368	>	}
2369	>	}
2370	>	}
2371	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2372	>	break;
2373	>	else if (tab == table) {
2374	>	int rs = resizeStamp(n);
2375	>	if (U.compareAndSwapInt(this, SIZECTL, sc,
2376	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2377	>	transfer(tab, null);
2378	>	}
2379	>	}
2380	>	}
2381	>
2382	>	/**
2383	>	* Moves and/or copies the nodes in each bin to new table. See
2384	>	* above for explanation.
2385	>	*/
2386	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2387	>	int n = tab.length, stride;
2388	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2389	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2390	>	if (nextTab == null) {            // initiating
2391	>	try {
2392	>	@SuppressWarnings("unchecked")
2393	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2394	>	nextTab = nt;
2395	>	} catch (Throwable ex) {      // try to cope with OOME
2396	>	sizeCtl = Integer.MAX_VALUE;
2397	>	return;
2398	>	}
2399	>	nextTable = nextTab;
2400	>	transferIndex = n;
2401	>	}
2402	>	int nextn = nextTab.length;
2403	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2404	>	boolean advance = true;
2405	>	boolean finishing = false; // to ensure sweep before committing nextTab
2406	>	for (int i = 0, bound = 0;;) {
2407	>	Node<K,V> f; int fh;
2408	>	while (advance) {
2409	>	int nextIndex, nextBound;
2410	>	if (--i >= bound || finishing)
2411	>	advance = false;
2412	>	else if ((nextIndex = transferIndex) <= 0) {
2413	>	i = -1;
2414	>	advance = false;
2415	>	}
2416	>	else if (U.compareAndSwapInt
2417	>	(this, TRANSFERINDEX, nextIndex,
2418	>	nextBound = (nextIndex > stride ?
2419	>	nextIndex - stride : 0))) {
2420	>	bound = nextBound;
2421	>	i = nextIndex - 1;
2422	>	advance = false;
2423	>	}
2424	>	}
2425	>	if (i < 0 || i >= n || i + n >= nextn) {
2426	>	int sc;
2427	>	if (finishing) {
2428	>	nextTable = null;
2429	>	table = nextTab;
2430	>	sizeCtl = (n << 1) - (n >>> 1);
2431	>	return;
2432	>	}
2433	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2434	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2435	>	return;
2436	>	finishing = advance = true;
2437	>	i = n; // recheck before commit
2438	>	}
2439	>	}
2440	>	else if ((f = tabAt(tab, i)) == null)
2441	>	advance = casTabAt(tab, i, null, fwd);
2442	>	else if ((fh = f.hash) == MOVED)
2443	>	advance = true; // already processed
2444	>	else {
2445	>	synchronized (f) {
2446	>	if (tabAt(tab, i) == f) {
2447	>	Node<K,V> ln, hn;
2448	>	if (fh >= 0) {
2449	>	int runBit = fh & n;
2450	>	Node<K,V> lastRun = f;
2451	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2452	>	int b = p.hash & n;
2453	>	if (b != runBit) {
2454	>	runBit = b;
2455	>	lastRun = p;
2456	>	}
2457	>	}
2458	>	if (runBit == 0) {
2459	>	ln = lastRun;
2460	>	hn = null;
2461	>	}
2462	>	else {
2463	>	hn = lastRun;
2464	>	ln = null;
2465	>	}
2466	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2467	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2468	>	if ((ph & n) == 0)
2469	>	ln = new Node<K,V>(ph, pk, pv, ln);
2470	>	else
2471	>	hn = new Node<K,V>(ph, pk, pv, hn);
2472	>	}
2473	>	setTabAt(nextTab, i, ln);
2474	>	setTabAt(nextTab, i + n, hn);
2475	>	setTabAt(tab, i, fwd);
2476	>	advance = true;
2477	>	}
2478	>	else if (f instanceof TreeBin) {
2479	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2480	>	TreeNode<K,V> lo = null, loTail = null;
2481	>	TreeNode<K,V> hi = null, hiTail = null;
2482	>	int lc = 0, hc = 0;
2483	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2484	>	int h = e.hash;
2485	>	TreeNode<K,V> p = new TreeNode<K,V>
2486	>	(h, e.key, e.val, null, null);
2487	>	if ((h & n) == 0) {
2488	>	if ((p.prev = loTail) == null)
2489	>	lo = p;
2490	>	else
2491	>	loTail.next = p;
2492	>	loTail = p;
2493	>	++lc;
2494	>	}
2495	>	else {
2496	>	if ((p.prev = hiTail) == null)
2497	>	hi = p;
2498	>	else
2499	>	hiTail.next = p;
2500	>	hiTail = p;
2501	>	++hc;
2502	>	}
2503	>	}
2504	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2505	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2506	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2507	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2508	>	setTabAt(nextTab, i, ln);
2509	>	setTabAt(nextTab, i + n, hn);
2510	>	setTabAt(tab, i, fwd);
2511	>	advance = true;
2512	>	}
2513	>	}
2514	>	}
2515	>	}
2516	>	}
2517	>	}
2518	>
2519	>	/* ---------------- Counter support -------------- */
2520	>
2521	>	/**
2522	>	* A padded cell for distributing counts.  Adapted from LongAdder
2523	>	* and Striped64.  See their internal docs for explanation.
2524	>	*/
2525	>	@sun.misc.Contended static final class CounterCell {
2526	>	volatile long value;
2527	>	CounterCell(long x) { value = x; }
2528	>	}
2529	>
2530	>	final long sumCount() {
2531	>	CounterCell[] as = counterCells; CounterCell a;
2532	>	long sum = baseCount;
2533	>	if (as != null) {
2534	>	for (int i = 0; i < as.length; ++i) {
2535	>	if ((a = as[i]) != null)
2536	>	sum += a.value;
2537	>	}
2538	>	}
2539	>	return sum;
2540	>	}
2541	>
2542	>	// See LongAdder version for explanation
2543	>	private final void fullAddCount(long x, boolean wasUncontended) {
2544	>	int h;
2545	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2546	>	ThreadLocalRandom.localInit();      // force initialization
2547	>	h = ThreadLocalRandom.getProbe();
2548	>	wasUncontended = true;
2549	>	}
2550	>	boolean collide = false;                // True if last slot nonempty
2551	>	for (;;) {
2552	>	CounterCell[] as; CounterCell a; int n; long v;
2553	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2554	>	if ((a = as[(n - 1) & h]) == null) {
2555	>	if (cellsBusy == 0) {            // Try to attach new Cell
2556	>	CounterCell r = new CounterCell(x); // Optimistic create
2557	>	if (cellsBusy == 0 &&
2558	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2559	>	boolean created = false;
2560	>	try {               // Recheck under lock
2561	>	CounterCell[] rs; int m, j;
2562	>	if ((rs = counterCells) != null &&
2563	>	(m = rs.length) > 0 &&
2564	>	rs[j = (m - 1) & h] == null) {
2565	>	rs[j] = r;
2566	>	created = true;
2567	>	}
2568	>	} finally {
2569	>	cellsBusy = 0;
2570	>	}
2571	>	if (created)
2572	>	break;
2573	>	continue;           // Slot is now non-empty
2574	>	}
2575	>	}
2576	>	collide = false;
2577	>	}
2578	>	else if (!wasUncontended)       // CAS already known to fail
2579	>	wasUncontended = true;      // Continue after rehash
2580	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2581	>	break;
2582	>	else if (counterCells != as || n >= NCPU)
2583	>	collide = false;            // At max size or stale
2584	>	else if (!collide)
2585	>	collide = true;
2586	>	else if (cellsBusy == 0 &&
2587	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2588	>	try {
2589	>	if (counterCells == as) {// Expand table unless stale
2590	>	CounterCell[] rs = new CounterCell[n << 1];
2591	>	for (int i = 0; i < n; ++i)
2592	>	rs[i] = as[i];
2593	>	counterCells = rs;
2594	>	}
2595	>	} finally {
2596	>	cellsBusy = 0;
2597	>	}
2598	>	collide = false;
2599	>	continue;                   // Retry with expanded table
2600	>	}
2601	>	h = ThreadLocalRandom.advanceProbe(h);
2602	>	}
2603	>	else if (cellsBusy == 0 && counterCells == as &&
2604	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2605	>	boolean init = false;
2606	>	try {                           // Initialize table
2607	>	if (counterCells == as) {
2608	>	CounterCell[] rs = new CounterCell[2];
2609	>	rs[h & 1] = new CounterCell(x);
2610	>	counterCells = rs;
2611	>	init = true;
2612	>	}
2613	>	} finally {
2614	>	cellsBusy = 0;
2615	>	}
2616	>	if (init)
2617	>	break;
2618	>	}
2619	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2620	>	break;                          // Fall back on using base
2621	>	}
2622	>	}
2623	>
2624	>	/* ---------------- Conversion from/to TreeBins -------------- */
2625	>
2626	>	/**
2627	>	* Replaces all linked nodes in bin at given index unless table is
2628	>	* too small, in which case resizes instead.
2629	>	*/
2630	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2631	>	Node<K,V> b; int n;
2632	>	if (tab != null) {
2633	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2634	>	tryPresize(n << 1);
2635	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2636	>	synchronized (b) {
2637	>	if (tabAt(tab, index) == b) {
2638	>	TreeNode<K,V> hd = null, tl = null;
2639	>	for (Node<K,V> e = b; e != null; e = e.next) {
2640	>	TreeNode<K,V> p =
2641	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2642	>	null, null);
2643	>	if ((p.prev = tl) == null)
2644	>	hd = p;
2645	>	else
2646	>	tl.next = p;
2647	>	tl = p;
2648	>	}
2649	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2650	>	}
2651	>	}
2652	>	}
2653	>	}
2654	>	}
2655	>
2656	>	/**
2657	>	* Returns a list on non-TreeNodes replacing those in given list.
2658	>	*/
2659	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2660	>	Node<K,V> hd = null, tl = null;
2661	>	for (Node<K,V> q = b; q != null; q = q.next) {
2662	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2663	>	if (tl == null)
2664	>	hd = p;
2665	>	else
2666	>	tl.next = p;
2667	>	tl = p;
2668	>	}
2669	>	return hd;
2670	>	}
2671	>
2672	>	/* ---------------- TreeNodes -------------- */
2673	>
2674	>	/**
2675	>	* Nodes for use in TreeBins
2676	>	*/
2677	>	static final class TreeNode<K,V> extends Node<K,V> {
2678	>	TreeNode<K,V> parent;  // red-black tree links
2679	>	TreeNode<K,V> left;
2680	>	TreeNode<K,V> right;
2681	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2682	>	boolean red;
2683	>
2684	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2685	>	TreeNode<K,V> parent) {
2686	>	super(hash, key, val, next);
2687	>	this.parent = parent;
2688	>	}
2689	>
2690	>	Node<K,V> find(int h, Object k) {
2691	>	return findTreeNode(h, k, null);
2692	>	}
2693	>
2694		/**
2695	<	* The number of elements in this segment's region.
2696	<	**/
2697	<	transient volatile int count;
2695	>	* Returns the TreeNode (or null if not found) for the given key
2696	>	* starting at given root.
2697	>	*/
2698	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2699	>	if (k != null) {
2700	>	TreeNode<K,V> p = this;
2701	>	do {
2702	>	int ph, dir; K pk; TreeNode<K,V> q;
2703	>	TreeNode<K,V> pl = p.left, pr = p.right;
2704	>	if ((ph = p.hash) > h)
2705	>	p = pl;
2706	>	else if (ph < h)
2707	>	p = pr;
2708	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2709	>	return p;
2710	>	else if (pl == null)
2711	>	p = pr;
2712	>	else if (pr == null)
2713	>	p = pl;
2714	>	else if ((kc != null ||
2715	>	(kc = comparableClassFor(k)) != null) &&
2716	>	(dir = compareComparables(kc, k, pk)) != 0)
2717	>	p = (dir < 0) ? pl : pr;
2718	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2719	>	return q;
2720	>	else
2721	>	p = pl;
2722	>	} while (p != null);
2723	>	}
2724	>	return null;
2725	>	}
2726	>	}
2727	>
2728	>	/* ---------------- TreeBins -------------- */
2729	>
2730	>	/**
2731	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2732	>	* keys or values, but instead point to list of TreeNodes and
2733	>	* their root. They also maintain a parasitic read-write lock
2734	>	* forcing writers (who hold bin lock) to wait for readers (who do
2735	>	* not) to complete before tree restructuring operations.
2736	>	*/
2737	>	static final class TreeBin<K,V> extends Node<K,V> {
2738	>	TreeNode<K,V> root;
2739	>	volatile TreeNode<K,V> first;
2740	>	volatile Thread waiter;
2741	>	volatile int lockState;
2742	>	// values for lockState
2743	>	static final int WRITER = 1; // set while holding write lock
2744	>	static final int WAITER = 2; // set when waiting for write lock
2745	>	static final int READER = 4; // increment value for setting read lock
2746
2747		/**
2748	<	* The table is rehashed when its size exceeds this threshold.
2749	<	* (The value of this field is always (int)(capacity *
2750	<	* loadFactor).)
2748	>	* Tie-breaking utility for ordering insertions when equal
2749	>	* hashCodes and non-comparable. We don't require a total
2750	>	* order, just a consistent insertion rule to maintain
2751	>	* equivalence across rebalancings. Tie-breaking further than
2752	>	* necessary simplifies testing a bit.
2753		*/
2754	<	transient private int threshold;
2754	>	static int tieBreakOrder(Object a, Object b) {
2755	>	int d;
2756	>	if (a == null || b == null ||
2757	>	(d = a.getClass().getName().
2758	>	compareTo(b.getClass().getName())) == 0)
2759	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2760	>	-1 : 1);
2761	>	return d;
2762	>	}
2763
2764		/**
2765	<	* The per-segment table
2765	>	* Creates bin with initial set of nodes headed by b.
2766		*/
2767	<	transient HashEntry<K,V>[] table;
2767	>	TreeBin(TreeNode<K,V> b) {
2768	>	super(TREEBIN, null, null, null);
2769	>	this.first = b;
2770	>	TreeNode<K,V> r = null;
2771	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2772	>	next = (TreeNode<K,V>)x.next;
2773	>	x.left = x.right = null;
2774	>	if (r == null) {
2775	>	x.parent = null;
2776	>	x.red = false;
2777	>	r = x;
2778	>	}
2779	>	else {
2780	>	K k = x.key;
2781	>	int h = x.hash;
2782	>	Class<?> kc = null;
2783	>	for (TreeNode<K,V> p = r;;) {
2784	>	int dir, ph;
2785	>	K pk = p.key;
2786	>	if ((ph = p.hash) > h)
2787	>	dir = -1;
2788	>	else if (ph < h)
2789	>	dir = 1;
2790	>	else if ((kc == null &&
2791	>	(kc = comparableClassFor(k)) == null) ||
2792	>	(dir = compareComparables(kc, k, pk)) == 0)
2793	>	dir = tieBreakOrder(k, pk);
2794	>	TreeNode<K,V> xp = p;
2795	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2796	>	x.parent = xp;
2797	>	if (dir <= 0)
2798	>	xp.left = x;
2799	>	else
2800	>	xp.right = x;
2801	>	r = balanceInsertion(r, x);
2802	>	break;
2803	>	}
2804	>	}
2805	>	}
2806	>	}
2807	>	this.root = r;
2808	>	assert checkInvariants(root);
2809	>	}
2810
2811		/**
2812	<	* The load factor for the hash table.  Even though this value
226	<	* is same for all segments, it is replicated to avoid needing
227	<	* links to outer object.
228	<	* @serial
2812	>	* Acquires write lock for tree restructuring.
2813		*/
2814	<	private final float loadFactor;
2814	>	private final void lockRoot() {
2815	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2816	>	contendedLock(); // offload to separate method
2817	>	}
2818
2819	<	Segment(int initialCapacity, float lf) {
2820	<	loadFactor = lf;
2821	<	setTable(new HashEntry<K,V>[initialCapacity]);
2819	>	/**
2820	>	* Releases write lock for tree restructuring.
2821	>	*/
2822	>	private final void unlockRoot() {
2823	>	lockState = 0;
2824		}
2825
2826		/**
2827	<	* Set table to new HashEntry array.
2828	<	* Call only while holding lock or in constructor.
2829	<	**/
2830	<	private void setTable(HashEntry<K,V>[] newTable) {
2831	<	table = newTable;
2832	<	threshold = (int)(newTable.length * loadFactor);
2833	<	count = count; // write-volatile
2834	<	}
2827	>	* Possibly blocks awaiting root lock.
2828	>	*/
2829	>	private final void contendedLock() {
2830	>	boolean waiting = false;
2831	>	for (int s;;) {
2832	>	if (((s = lockState) & ~WAITER) == 0) {
2833	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2834	>	if (waiting)
2835	>	waiter = null;
2836	>	return;
2837	>	}
2838	>	}
2839	>	else if ((s & WAITER) == 0) {
2840	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2841	>	waiting = true;
2842	>	waiter = Thread.currentThread();
2843	>	}
2844	>	}
2845	>	else if (waiting)
2846	>	LockSupport.park(this);
2847	>	}
2848	>	}
2849
2850	<	/* Specialized implementations of map methods */
2851	<
2852	<	V get(K key, int hash) {
2853	<	if (count != 0) { // read-volatile
2854	<	HashEntry<K,V>[] tab = table;
2855	<	int index = indexFor(hash, tab.length);
2856	<	HashEntry<K,V> e = tab[index];
2857	<	while (e != null) {
2858	<	if (e.hash == hash && eq(key, e.key))
2859	<	return e.value;
2860	<	e = e.next;
2850	>	/**
2851	>	* Returns matching node or null if none. Tries to search
2852	>	* using tree comparisons from root, but continues linear
2853	>	* search when lock not available.
2854	>	*/
2855	>	final Node<K,V> find(int h, Object k) {
2856	>	if (k != null) {
2857	>	for (Node<K,V> e = first; e != null; ) {
2858	>	int s; K ek;
2859	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2860	>	if (e.hash == h &&
2861	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2862	>	return e;
2863	>	e = e.next;
2864	>	}
2865	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2866	>	s + READER)) {
2867	>	TreeNode<K,V> r, p;
2868	>	try {
2869	>	p = ((r = root) == null ? null :
2870	>	r.findTreeNode(h, k, null));
2871	>	} finally {
2872	>	Thread w;
2873	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2874	>	(READER|WAITER) && (w = waiter) != null)
2875	>	LockSupport.unpark(w);
2876	>	}
2877	>	return p;
2878	>	}
2879		}
2880		}
2881		return null;
2882		}
2883
2884	<	boolean containsKey(Object key, int hash) {
2885	<	if (count != 0) { // read-volatile
2886	<	HashEntry<K,V>[] tab = table;
2887	<	int index = indexFor(hash, tab.length);
2888	<	HashEntry<K,V> e = tab[index];
2889	<	while (e != null) {
2890	<	if (e.hash == hash && eq(key, e.key))
2891	<	return true;
2892	<	e = e.next;
2884	>	/**
2885	>	* Finds or adds a node.
2886	>	* @return null if added
2887	>	*/
2888	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2889	>	Class<?> kc = null;
2890	>	boolean searched = false;
2891	>	for (TreeNode<K,V> p = root;;) {
2892	>	int dir, ph; K pk;
2893	>	if (p == null) {
2894	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2895	>	break;
2896	>	}
2897	>	else if ((ph = p.hash) > h)
2898	>	dir = -1;
2899	>	else if (ph < h)
2900	>	dir = 1;
2901	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2902	>	return p;
2903	>	else if ((kc == null &&
2904	>	(kc = comparableClassFor(k)) == null) ||
2905	>	(dir = compareComparables(kc, k, pk)) == 0) {
2906	>	if (!searched) {
2907	>	TreeNode<K,V> q, ch;
2908	>	searched = true;
2909	>	if (((ch = p.left) != null &&
2910	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2911	>	((ch = p.right) != null &&
2912	>	(q = ch.findTreeNode(h, k, kc)) != null))
2913	>	return q;
2914	>	}
2915	>	dir = tieBreakOrder(k, pk);
2916	>	}
2917	>
2918	>	TreeNode<K,V> xp = p;
2919	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2920	>	TreeNode<K,V> x, f = first;
2921	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2922	>	if (f != null)
2923	>	f.prev = x;
2924	>	if (dir <= 0)
2925	>	xp.left = x;
2926	>	else
2927	>	xp.right = x;
2928	>	if (!xp.red)
2929	>	x.red = true;
2930	>	else {
2931	>	lockRoot();
2932	>	try {
2933	>	root = balanceInsertion(root, x);
2934	>	} finally {
2935	>	unlockRoot();
2936	>	}
2937	>	}
2938	>	break;
2939		}
2940		}
2941	<	return false;
2941	>	assert checkInvariants(root);
2942	>	return null;
2943		}
2944	<
2945	<	boolean containsValue(Object value) {
2946	<	if (count != 0) { // read-volatile
2947	<	HashEntry<K,V> tab[] = table;
2948	<	int len = tab.length;
2949	<	for (int i = 0 ; i < len; i++)
2950	<	for (HashEntry<K,V> e = tab[i] ; e != null ; e = e.next)
2951	<	if (value.equals(e.value))
2952	<	return true;
2944	>
2945	>	/**
2946	>	* Removes the given node, that must be present before this
2947	>	* call.  This is messier than typical red-black deletion code
2948	>	* because we cannot swap the contents of an interior node
2949	>	* with a leaf successor that is pinned by "next" pointers
2950	>	* that are accessible independently of lock. So instead we
2951	>	* swap the tree linkages.
2952	>	*
2953	>	* @return true if now too small, so should be untreeified
2954	>	*/
2955	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2956	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2957	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2958	>	TreeNode<K,V> r, rl;
2959	>	if (pred == null)
2960	>	first = next;
2961	>	else
2962	>	pred.next = next;
2963	>	if (next != null)
2964	>	next.prev = pred;
2965	>	if (first == null) {
2966	>	root = null;
2967	>	return true;
2968	>	}
2969	>	if ((r = root) == null || r.right == null || // too small
2970	>	(rl = r.left) == null || rl.left == null)
2971	>	return true;
2972	>	lockRoot();
2973	>	try {
2974	>	TreeNode<K,V> replacement;
2975	>	TreeNode<K,V> pl = p.left;
2976	>	TreeNode<K,V> pr = p.right;
2977	>	if (pl != null && pr != null) {
2978	>	TreeNode<K,V> s = pr, sl;
2979	>	while ((sl = s.left) != null) // find successor
2980	>	s = sl;
2981	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2982	>	TreeNode<K,V> sr = s.right;
2983	>	TreeNode<K,V> pp = p.parent;
2984	>	if (s == pr) { // p was s's direct parent
2985	>	p.parent = s;
2986	>	s.right = p;
2987	>	}
2988	>	else {
2989	>	TreeNode<K,V> sp = s.parent;
2990	>	if ((p.parent = sp) != null) {
2991	>	if (s == sp.left)
2992	>	sp.left = p;
2993	>	else
2994	>	sp.right = p;
2995	>	}
2996	>	if ((s.right = pr) != null)
2997	>	pr.parent = s;
2998	>	}
2999	>	p.left = null;
3000	>	if ((p.right = sr) != null)
3001	>	sr.parent = p;
3002	>	if ((s.left = pl) != null)
3003	>	pl.parent = s;
3004	>	if ((s.parent = pp) == null)
3005	>	r = s;
3006	>	else if (p == pp.left)
3007	>	pp.left = s;
3008	>	else
3009	>	pp.right = s;
3010	>	if (sr != null)
3011	>	replacement = sr;
3012	>	else
3013	>	replacement = p;
3014	>	}
3015	>	else if (pl != null)
3016	>	replacement = pl;
3017	>	else if (pr != null)
3018	>	replacement = pr;
3019	>	else
3020	>	replacement = p;
3021	>	if (replacement != p) {
3022	>	TreeNode<K,V> pp = replacement.parent = p.parent;
3023	>	if (pp == null)
3024	>	r = replacement;
3025	>	else if (p == pp.left)
3026	>	pp.left = replacement;
3027	>	else
3028	>	pp.right = replacement;
3029	>	p.left = p.right = p.parent = null;
3030	>	}
3031	>
3032	>	root = (p.red) ? r : balanceDeletion(r, replacement);
3033	>
3034	>	if (p == replacement) {  // detach pointers
3035	>	TreeNode<K,V> pp;
3036	>	if ((pp = p.parent) != null) {
3037	>	if (p == pp.left)
3038	>	pp.left = null;
3039	>	else if (p == pp.right)
3040	>	pp.right = null;
3041	>	p.parent = null;
3042	>	}
3043	>	}
3044	>	} finally {
3045	>	unlockRoot();
3046		}
3047	+	assert checkInvariants(root);
3048		return false;
3049		}
3050
3051	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
3052	<	lock();
3053	<	try {
3054	<	HashEntry<K,V>[] tab = table;
3055	<	int index = indexFor(hash, tab.length);
3056	<	HashEntry<K,V> first = tab[index];
3057	<
3058	<	for (HashEntry<K,V> e = first; e != null; e = e.next) {
3059	<	if (e.hash == hash && eq(key, e.key)) {
3060	<	V oldValue = e.value;
3061	<	if (!onlyIfAbsent)
3062	<	e.value = value;
3063	<	count = count; // write-volatile
3064	<	return oldValue;
3065	<	}
3066	<	}
3067	<
306	<	tab[index] = new HashEntry<K,V>(hash, key, value, first);
307	<	if (++count > threshold) // write-volatile
308	<	rehash();
309	<	return null;
310	<	}
311	<	finally {
312	<	unlock();
3051	>	/* ------------------------------------------------------------ */
3052	>	// Red-black tree methods, all adapted from CLR
3053	>
3054	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3055	>	TreeNode<K,V> p) {
3056	>	TreeNode<K,V> r, pp, rl;
3057	>	if (p != null && (r = p.right) != null) {
3058	>	if ((rl = p.right = r.left) != null)
3059	>	rl.parent = p;
3060	>	if ((pp = r.parent = p.parent) == null)
3061	>	(root = r).red = false;
3062	>	else if (pp.left == p)
3063	>	pp.left = r;
3064	>	else
3065	>	pp.right = r;
3066	>	r.left = p;
3067	>	p.parent = r;
3068		}
3069	+	return root;
3070		}
3071
3072	<	private void rehash() {
3073	<	HashEntry<K,V>[] oldTable = table;
3074	<	int oldCapacity = oldTable.length;
3075	<	if (oldCapacity >= MAXIMUM_CAPACITY)
3076	<	return;
3072	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3073	>	TreeNode<K,V> p) {
3074	>	TreeNode<K,V> l, pp, lr;
3075	>	if (p != null && (l = p.left) != null) {
3076	>	if ((lr = p.left = l.right) != null)
3077	>	lr.parent = p;
3078	>	if ((pp = l.parent = p.parent) == null)
3079	>	(root = l).red = false;
3080	>	else if (pp.right == p)
3081	>	pp.right = l;
3082	>	else
3083	>	pp.left = l;
3084	>	l.right = p;
3085	>	p.parent = l;
3086	>	}
3087	>	return root;
3088	>	}
3089
3090	<	/*
3091	<	* Reclassify nodes in each list to new Map.  Because we are
3092	<	* using power-of-two expansion, the elements from each bin
3093	<	* must either stay at same index, or move with a power of two
3094	<	* offset. We eliminate unnecessary node creation by catching
3095	<	* cases where old nodes can be reused because their next
3096	<	* fields won't change. Statistically, at the default
3097	<	* threshhold, only about one-sixth of them need cloning when
3098	<	* a table doubles. The nodes they replace will be garbage
3099	<	* collectable as soon as they are no longer referenced by any
3100	<	* reader thread that may be in the midst of traversing table
3101	<	* right now.
3102	<	*/
3103	<
3104	<	HashEntry<K,V>[] newTable = new HashEntry<K,V>[oldCapacity << 1];
3105	<	int sizeMask = newTable.length - 1;
3106	<	for (int i = 0; i < oldCapacity ; i++) {
3107	<	// We need to guarantee that any existing reads of old Map can
3108	<	//  proceed. So we cannot yet null out each bin.
3109	<	HashEntry<K,V> e = oldTable[i];
3110	<
3111	<	if (e != null) {
3112	<	HashEntry<K,V> next = e.next;
3113	<	int idx = e.hash & sizeMask;
3114	<
3115	<	//  Single node on list
3116	<	if (next == null)
3117	<	newTable[idx] = e;
3118	<
3119	<	else {
3120	<	// Reuse trailing consecutive sequence at same slot
3121	<	HashEntry<K,V> lastRun = e;
3122	<	int lastIdx = idx;
3123	<	for (HashEntry<K,V> last = next;
3124	<	last != null;
3125	<	last = last.next) {
3126	<	int k = last.hash & sizeMask;
3127	<	if (k != lastIdx) {
3128	<	lastIdx = k;
3129	<	lastRun = last;
3130	<	}
3131	<	}
3132	<	newTable[lastIdx] = lastRun;
3133	<
3134	<	// Clone all remaining nodes
3135	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
3136	<	int k = p.hash & sizeMask;
3137	<	newTable[k] = new HashEntry<K,V>(p.hash, p.key,
3138	<	p.value, newTable[k]);
3090	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3091	>	TreeNode<K,V> x) {
3092	>	x.red = true;
3093	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3094	>	if ((xp = x.parent) == null) {
3095	>	x.red = false;
3096	>	return x;
3097	>	}
3098	>	else if (!xp.red || (xpp = xp.parent) == null)
3099	>	return root;
3100	>	if (xp == (xppl = xpp.left)) {
3101	>	if ((xppr = xpp.right) != null && xppr.red) {
3102	>	xppr.red = false;
3103	>	xp.red = false;
3104	>	xpp.red = true;
3105	>	x = xpp;
3106	>	}
3107	>	else {
3108	>	if (x == xp.right) {
3109	>	root = rotateLeft(root, x = xp);
3110	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3111	>	}
3112	>	if (xp != null) {
3113	>	xp.red = false;
3114	>	if (xpp != null) {
3115	>	xpp.red = true;
3116	>	root = rotateRight(root, xpp);
3117	>	}
3118	>	}
3119	>	}
3120	>	}
3121	>	else {
3122	>	if (xppl != null && xppl.red) {
3123	>	xppl.red = false;
3124	>	xp.red = false;
3125	>	xpp.red = true;
3126	>	x = xpp;
3127	>	}
3128	>	else {
3129	>	if (x == xp.left) {
3130	>	root = rotateRight(root, x = xp);
3131	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3132	>	}
3133	>	if (xp != null) {
3134	>	xp.red = false;
3135	>	if (xpp != null) {
3136	>	xpp.red = true;
3137	>	root = rotateLeft(root, xpp);
3138	>	}
3139	>	}
3140	>	}
3141	>	}
3142	>	}
3143	>	}
3144	>
3145	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3146	>	TreeNode<K,V> x) {
3147	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3148	>	if (x == null || x == root)
3149	>	return root;
3150	>	else if ((xp = x.parent) == null) {
3151	>	x.red = false;
3152	>	return x;
3153	>	}
3154	>	else if (x.red) {
3155	>	x.red = false;
3156	>	return root;
3157	>	}
3158	>	else if ((xpl = xp.left) == x) {
3159	>	if ((xpr = xp.right) != null && xpr.red) {
3160	>	xpr.red = false;
3161	>	xp.red = true;
3162	>	root = rotateLeft(root, xp);
3163	>	xpr = (xp = x.parent) == null ? null : xp.right;
3164	>	}
3165	>	if (xpr == null)
3166	>	x = xp;
3167	>	else {
3168	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3169	>	if ((sr == null || !sr.red) &&
3170	>	(sl == null || !sl.red)) {
3171	>	xpr.red = true;
3172	>	x = xp;
3173	>	}
3174	>	else {
3175	>	if (sr == null || !sr.red) {
3176	>	if (sl != null)
3177	>	sl.red = false;
3178	>	xpr.red = true;
3179	>	root = rotateRight(root, xpr);
3180	>	xpr = (xp = x.parent) == null ?
3181	>	null : xp.right;
3182	>	}
3183	>	if (xpr != null) {
3184	>	xpr.red = (xp == null) ? false : xp.red;
3185	>	if ((sr = xpr.right) != null)
3186	>	sr.red = false;
3187	>	}
3188	>	if (xp != null) {
3189	>	xp.red = false;
3190	>	root = rotateLeft(root, xp);
3191	>	}
3192	>	x = root;
3193	>	}
3194	>	}
3195	>	}
3196	>	else { // symmetric
3197	>	if (xpl != null && xpl.red) {
3198	>	xpl.red = false;
3199	>	xp.red = true;
3200	>	root = rotateRight(root, xp);
3201	>	xpl = (xp = x.parent) == null ? null : xp.left;
3202	>	}
3203	>	if (xpl == null)
3204	>	x = xp;
3205	>	else {
3206	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3207	>	if ((sl == null || !sl.red) &&
3208	>	(sr == null || !sr.red)) {
3209	>	xpl.red = true;
3210	>	x = xp;
3211	>	}
3212	>	else {
3213	>	if (sl == null || !sl.red) {
3214	>	if (sr != null)
3215	>	sr.red = false;
3216	>	xpl.red = true;
3217	>	root = rotateLeft(root, xpl);
3218	>	xpl = (xp = x.parent) == null ?
3219	>	null : xp.left;
3220	>	}
3221	>	if (xpl != null) {
3222	>	xpl.red = (xp == null) ? false : xp.red;
3223	>	if ((sl = xpl.left) != null)
3224	>	sl.red = false;
3225	>	}
3226	>	if (xp != null) {
3227	>	xp.red = false;
3228	>	root = rotateRight(root, xp);
3229	>	}
3230	>	x = root;
3231		}
3232		}
3233		}
3234		}
375	–	setTable(newTable);
3235		}
3236
3237		/**
3238	<	* Remove; match on key only if value null, else match both.
3238	>	* Recursive invariant check
3239		*/
3240	<	V remove(Object key, int hash, Object value) {
3241	<	lock();
3242	<	try {
3243	<	HashEntry[] tab = table;
3244	<	int index = indexFor(hash, tab.length);
3245	<	HashEntry<K,V> first = tab[index];
3246	<
3247	<	HashEntry<K,V> e = first;
3248	<	while (true) {
3249	<	if (e == null)
3250	<	return null;
3251	<	if (e.hash == hash && eq(key, e.key))
3252	<	break;
3253	<	e = e.next;
3254	<	}
3240	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3241	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3242	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3243	>	if (tb != null && tb.next != t)
3244	>	return false;
3245	>	if (tn != null && tn.prev != t)
3246	>	return false;
3247	>	if (tp != null && t != tp.left && t != tp.right)
3248	>	return false;
3249	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3250	>	return false;
3251	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3252	>	return false;
3253	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3254	>	return false;
3255	>	if (tl != null && !checkInvariants(tl))
3256	>	return false;
3257	>	if (tr != null && !checkInvariants(tr))
3258	>	return false;
3259	>	return true;
3260	>	}
3261
3262	<	V oldValue = e.value;
3263	<	if (value != null && !value.equals(oldValue))
3264	<	return null;
3265	<
3266	<	// All entries following removed node can stay in list, but
3267	<	// all preceeding ones need to be cloned.
3268	<	HashEntry<K,V> newFirst = e.next;
3269	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
405	<	newFirst = new HashEntry<K,V>(p.hash, p.key, p.value, newFirst);
406	<	tab[index] = newFirst;
407	<
408	<	count--; // write-volatile
409	<	return e.value;
410	<	}
411	<	finally {
412	<	unlock();
3262	>	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
3263	>	private static final long LOCKSTATE;
3264	>	static {
3265	>	try {
3266	>	LOCKSTATE = U.objectFieldOffset
3267	>	(TreeBin.class.getDeclaredField("lockState"));
3268	>	} catch (ReflectiveOperationException e) {
3269	>	throw new Error(e);
3270		}
3271		}
3272	+	}
3273
3274	<	void clear() {
3275	<	lock();
3276	<	try {
3277	<	HashEntry<K,V> tab[] = table;
3278	<	for (int i = 0; i < tab.length ; i++)
3279	<	tab[i] = null;
3280	<	count = 0; // write-volatile
3274	>	/* ----------------Table Traversal -------------- */
3275	>
3276	>	/**
3277	>	* Records the table, its length, and current traversal index for a
3278	>	* traverser that must process a region of a forwarded table before
3279	>	* proceeding with current table.
3280	>	*/
3281	>	static final class TableStack<K,V> {
3282	>	int length;
3283	>	int index;
3284	>	Node<K,V>[] tab;
3285	>	TableStack<K,V> next;
3286	>	}
3287	>
3288	>	/**
3289	>	* Encapsulates traversal for methods such as containsValue; also
3290	>	* serves as a base class for other iterators and spliterators.
3291	>	*
3292	>	* Method advance visits once each still-valid node that was
3293	>	* reachable upon iterator construction. It might miss some that
3294	>	* were added to a bin after the bin was visited, which is OK wrt
3295	>	* consistency guarantees. Maintaining this property in the face
3296	>	* of possible ongoing resizes requires a fair amount of
3297	>	* bookkeeping state that is difficult to optimize away amidst
3298	>	* volatile accesses.  Even so, traversal maintains reasonable
3299	>	* throughput.
3300	>	*
3301	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3302	>	* However, if the table has been resized, then all future steps
3303	>	* must traverse both the bin at the current index as well as at
3304	>	* (index + baseSize); and so on for further resizings. To
3305	>	* paranoically cope with potential sharing by users of iterators
3306	>	* across threads, iteration terminates if a bounds checks fails
3307	>	* for a table read.
3308	>	*/
3309	>	static class Traverser<K,V> {
3310	>	Node<K,V>[] tab;        // current table; updated if resized
3311	>	Node<K,V> next;         // the next entry to use
3312	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3313	>	int index;              // index of bin to use next
3314	>	int baseIndex;          // current index of initial table
3315	>	int baseLimit;          // index bound for initial table
3316	>	final int baseSize;     // initial table size
3317	>
3318	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3319	>	this.tab = tab;
3320	>	this.baseSize = size;
3321	>	this.baseIndex = this.index = index;
3322	>	this.baseLimit = limit;
3323	>	this.next = null;
3324	>	}
3325	>
3326	>	/**
3327	>	* Advances if possible, returning next valid node, or null if none.
3328	>	*/
3329	>	final Node<K,V> advance() {
3330	>	Node<K,V> e;
3331	>	if ((e = next) != null)
3332	>	e = e.next;
3333	>	for (;;) {
3334	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3335	>	if (e != null)
3336	>	return next = e;
3337	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3338	>	(n = t.length) <= (i = index) || i < 0)
3339	>	return next = null;
3340	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3341	>	if (e instanceof ForwardingNode) {
3342	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3343	>	e = null;
3344	>	pushState(t, i, n);
3345	>	continue;
3346	>	}
3347	>	else if (e instanceof TreeBin)
3348	>	e = ((TreeBin<K,V>)e).first;
3349	>	else
3350	>	e = null;
3351	>	}
3352	>	if (stack != null)
3353	>	recoverState(n);
3354	>	else if ((index = i + baseSize) >= n)
3355	>	index = ++baseIndex; // visit upper slots if present
3356		}
3357	<	finally {
3358	<	unlock();
3357	>	}
3358	>
3359	>	/**
3360	>	* Saves traversal state upon encountering a forwarding node.
3361	>	*/
3362	>	private void pushState(Node<K,V>[] t, int i, int n) {
3363	>	TableStack<K,V> s = spare;  // reuse if possible
3364	>	if (s != null)
3365	>	spare = s.next;
3366	>	else
3367	>	s = new TableStack<K,V>();
3368	>	s.tab = t;
3369	>	s.length = n;
3370	>	s.index = i;
3371	>	s.next = stack;
3372	>	stack = s;
3373	>	}
3374	>
3375	>	/**
3376	>	* Possibly pops traversal state.
3377	>	*
3378	>	* @param n length of current table
3379	>	*/
3380	>	private void recoverState(int n) {
3381	>	TableStack<K,V> s; int len;
3382	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3383	>	n = len;
3384	>	index = s.index;
3385	>	tab = s.tab;
3386	>	s.tab = null;
3387	>	TableStack<K,V> next = s.next;
3388	>	s.next = spare; // save for reuse
3389	>	stack = next;
3390	>	spare = s;
3391		}
3392	+	if (s == null && (index += baseSize) >= n)
3393	+	index = ++baseIndex;
3394		}
3395		}
3396
3397		/**
3398	<	* ConcurrentReaderHashMap list entry.
3398	>	* Base of key, value, and entry Iterators. Adds fields to
3399	>	* Traverser to support iterator.remove.
3400		*/
3401	<	private static class HashEntry<K,V> implements Entry<K,V> {
3402	<	private final K key;
3403	<	private V value;
3404	<	private final int hash;
3405	<	private final HashEntry<K,V> next;
3401	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3402	>	final ConcurrentHashMap<K,V> map;
3403	>	Node<K,V> lastReturned;
3404	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3405	>	ConcurrentHashMap<K,V> map) {
3406	>	super(tab, size, index, limit);
3407	>	this.map = map;
3408	>	advance();
3409	>	}
3410
3411	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
3412	<	this.value = value;
3413	<	this.hash = hash;
3414	<	this.key = key;
3415	<	this.next = next;
3411	>	public final boolean hasNext() { return next != null; }
3412	>	public final boolean hasMoreElements() { return next != null; }
3413	>
3414	>	public final void remove() {
3415	>	Node<K,V> p;
3416	>	if ((p = lastReturned) == null)
3417	>	throw new IllegalStateException();
3418	>	lastReturned = null;
3419	>	map.replaceNode(p.key, null, null);
3420	>	}
3421	>	}
3422	>
3423	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3424	>	implements Iterator<K>, Enumeration<K> {
3425	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3426	>	ConcurrentHashMap<K,V> map) {
3427	>	super(tab, index, size, limit, map);
3428		}
3429
3430	<	public K getKey() {
3431	<	return key;
3430	>	public final K next() {
3431	>	Node<K,V> p;
3432	>	if ((p = next) == null)
3433	>	throw new NoSuchElementException();
3434	>	K k = p.key;
3435	>	lastReturned = p;
3436	>	advance();
3437	>	return k;
3438		}
3439
3440	<	public V getValue() {
3441	<	return value;
3440	>	public final K nextElement() { return next(); }
3441	>	}
3442	>
3443	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3444	>	implements Iterator<V>, Enumeration<V> {
3445	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3446	>	ConcurrentHashMap<K,V> map) {
3447	>	super(tab, index, size, limit, map);
3448	>	}
3449	>
3450	>	public final V next() {
3451	>	Node<K,V> p;
3452	>	if ((p = next) == null)
3453	>	throw new NoSuchElementException();
3454	>	V v = p.val;
3455	>	lastReturned = p;
3456	>	advance();
3457	>	return v;
3458		}
3459
3460	<	public V setValue(V newValue) {
3461	<	// We aren't required to, and don't provide any
3462	<	// visibility barriers for setting value.
3463	<	if (newValue == null)
3464	<	throw new NullPointerException();
3465	<	V oldValue = this.value;
3466	<	this.value = newValue;
3467	<	return oldValue;
3460	>	public final V nextElement() { return next(); }
3461	>	}
3462	>
3463	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3464	>	implements Iterator<Map.Entry<K,V>> {
3465	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3466	>	ConcurrentHashMap<K,V> map) {
3467	>	super(tab, index, size, limit, map);
3468	>	}
3469	>
3470	>	public final Map.Entry<K,V> next() {
3471	>	Node<K,V> p;
3472	>	if ((p = next) == null)
3473	>	throw new NoSuchElementException();
3474	>	K k = p.key;
3475	>	V v = p.val;
3476	>	lastReturned = p;
3477	>	advance();
3478	>	return new MapEntry<K,V>(k, v, map);
3479	>	}
3480	>	}
3481	>
3482	>	/**
3483	>	* Exported Entry for EntryIterator
3484	>	*/
3485	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3486	>	final K key; // non-null
3487	>	V val;       // non-null
3488	>	final ConcurrentHashMap<K,V> map;
3489	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3490	>	this.key = key;
3491	>	this.val = val;
3492	>	this.map = map;
3493	>	}
3494	>	public K getKey()        { return key; }
3495	>	public V getValue()      { return val; }
3496	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3497	>	public String toString() {
3498	>	return Helpers.mapEntryToString(key, val);
3499		}
3500
3501		public boolean equals(Object o) {
3502	<	if (!(o instanceof Entry))
3502	>	Object k, v; Map.Entry<?,?> e;
3503	>	return ((o instanceof Map.Entry) &&
3504	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3505	>	(v = e.getValue()) != null &&
3506	>	(k == key || k.equals(key)) &&
3507	>	(v == val || v.equals(val)));
3508	>	}
3509	>
3510	>	/**
3511	>	* Sets our entry's value and writes through to the map. The
3512	>	* value to return is somewhat arbitrary here. Since we do not
3513	>	* necessarily track asynchronous changes, the most recent
3514	>	* "previous" value could be different from what we return (or
3515	>	* could even have been removed, in which case the put will
3516	>	* re-establish). We do not and cannot guarantee more.
3517	>	*/
3518	>	public V setValue(V value) {
3519	>	if (value == null) throw new NullPointerException();
3520	>	V v = val;
3521	>	val = value;
3522	>	map.put(key, value);
3523	>	return v;
3524	>	}
3525	>	}
3526	>
3527	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3528	>	implements Spliterator<K> {
3529	>	long est;               // size estimate
3530	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3531	>	long est) {
3532	>	super(tab, size, index, limit);
3533	>	this.est = est;
3534	>	}
3535	>
3536	>	public Spliterator<K> trySplit() {
3537	>	int i, f, h;
3538	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3539	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3540	>	f, est >>>= 1);
3541	>	}
3542	>
3543	>	public void forEachRemaining(Consumer<? super K> action) {
3544	>	if (action == null) throw new NullPointerException();
3545	>	for (Node<K,V> p; (p = advance()) != null;)
3546	>	action.accept(p.key);
3547	>	}
3548	>
3549	>	public boolean tryAdvance(Consumer<? super K> action) {
3550	>	if (action == null) throw new NullPointerException();
3551	>	Node<K,V> p;
3552	>	if ((p = advance()) == null)
3553		return false;
3554	<	Entry<K,V> e = (Entry)o;
3555	<	return (key.equals(e.getKey()) && value.equals(e.getValue()));
3554	>	action.accept(p.key);
3555	>	return true;
3556		}
3557	<
3558	<	public int hashCode() {
3559	<	return  key.hashCode() ^ value.hashCode();
3557	>
3558	>	public long estimateSize() { return est; }
3559	>
3560	>	public int characteristics() {
3561	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3562	>	Spliterator.NONNULL;
3563		}
3564	+	}
3565
3566	<	public String toString() {
3567	<	return key + "=" + value;
3566	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3567	>	implements Spliterator<V> {
3568	>	long est;               // size estimate
3569	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3570	>	long est) {
3571	>	super(tab, size, index, limit);
3572	>	this.est = est;
3573	>	}
3574	>
3575	>	public Spliterator<V> trySplit() {
3576	>	int i, f, h;
3577	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3578	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3579	>	f, est >>>= 1);
3580	>	}
3581	>
3582	>	public void forEachRemaining(Consumer<? super V> action) {
3583	>	if (action == null) throw new NullPointerException();
3584	>	for (Node<K,V> p; (p = advance()) != null;)
3585	>	action.accept(p.val);
3586	>	}
3587	>
3588	>	public boolean tryAdvance(Consumer<? super V> action) {
3589	>	if (action == null) throw new NullPointerException();
3590	>	Node<K,V> p;
3591	>	if ((p = advance()) == null)
3592	>	return false;
3593	>	action.accept(p.val);
3594	>	return true;
3595	>	}
3596	>
3597	>	public long estimateSize() { return est; }
3598	>
3599	>	public int characteristics() {
3600	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3601		}
3602		}
3603
3604	<
3605	<	/* ---------------- Public operations -------------- */
3604	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3605	>	implements Spliterator<Map.Entry<K,V>> {
3606	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3607	>	long est;               // size estimate
3608	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3609	>	long est, ConcurrentHashMap<K,V> map) {
3610	>	super(tab, size, index, limit);
3611	>	this.map = map;
3612	>	this.est = est;
3613	>	}
3614	>
3615	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3616	>	int i, f, h;
3617	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3618	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3619	>	f, est >>>= 1, map);
3620	>	}
3621	>
3622	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3623	>	if (action == null) throw new NullPointerException();
3624	>	for (Node<K,V> p; (p = advance()) != null; )
3625	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3626	>	}
3627	>
3628	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3629	>	if (action == null) throw new NullPointerException();
3630	>	Node<K,V> p;
3631	>	if ((p = advance()) == null)
3632	>	return false;
3633	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3634	>	return true;
3635	>	}
3636	>
3637	>	public long estimateSize() { return est; }
3638	>
3639	>	public int characteristics() {
3640	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3641	>	Spliterator.NONNULL;
3642	>	}
3643	>	}
3644	>
3645	>	// Parallel bulk operations
3646
3647		/**
3648	<	* Constructs a new, empty map with the specified initial
3649	<	* capacity and the specified load factor.
3648	>	* Computes initial batch value for bulk tasks. The returned value
3649	>	* is approximately exp2 of the number of times (minus one) to
3650	>	* split task by two before executing leaf action. This value is
3651	>	* faster to compute and more convenient to use as a guide to
3652	>	* splitting than is the depth, since it is used while dividing by
3653	>	* two anyway.
3654	>	*/
3655	>	final int batchFor(long b) {
3656	>	long n;
3657	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3658	>	return 0;
3659	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3660	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3661	>	}
3662	>
3663	>	/**
3664	>	* Performs the given action for each (key, value).
3665		*
3666	<	* @param initialCapacity the initial capacity.  The actual
3667	<	* initial capacity is rounded up to the nearest power of two.
3668	<	* @param loadFactor  the load factor threshold, used to control resizing.
3669	<	* @param segments the number of concurrently accessible segments. the
491	<	* actual number of segments is rounded to the next power of two.
492	<	* @throws IllegalArgumentException if the initial capacity is
493	<	* negative or the load factor or number of segments are
494	<	* nonpositive.
3666	>	* @param parallelismThreshold the (estimated) number of elements
3667	>	* needed for this operation to be executed in parallel
3668	>	* @param action the action
3669	>	* @since 1.8
3670		*/
3671	<	public ConcurrentHashMap(int initialCapacity, float loadFactor, int segments) {
3672	<	if (!(loadFactor > 0) || initialCapacity < 0 || segments <= 0)
3673	<	throw new IllegalArgumentException();
3671	>	public void forEach(long parallelismThreshold,
3672	>	BiConsumer<? super K,? super V> action) {
3673	>	if (action == null) throw new NullPointerException();
3674	>	new ForEachMappingTask<K,V>
3675	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3676	>	action).invoke();
3677	>	}
3678
3679	<	// Find power-of-two sizes best matching arguments
3680	<	int sshift = 0;
3681	<	int ssize = 1;
3682	<	while (ssize < segments) {
3683	<	++sshift;
3684	<	ssize <<= 1;
3685	<	}
3686	<	segmentShift = sshift;
3687	<	segmentMask = ssize-1;
3688	<	this.segments = new Segment<K,V>[ssize];
3679	>	/**
3680	>	* Performs the given action for each non-null transformation
3681	>	* of each (key, value).
3682	>	*
3683	>	* @param parallelismThreshold the (estimated) number of elements
3684	>	* needed for this operation to be executed in parallel
3685	>	* @param transformer a function returning the transformation
3686	>	* for an element, or null if there is no transformation (in
3687	>	* which case the action is not applied)
3688	>	* @param action the action
3689	>	* @param <U> the return type of the transformer
3690	>	* @since 1.8
3691	>	*/
3692	>	public <U> void forEach(long parallelismThreshold,
3693	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3694	>	Consumer<? super U> action) {
3695	>	if (transformer == null || action == null)
3696	>	throw new NullPointerException();
3697	>	new ForEachTransformedMappingTask<K,V,U>
3698	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3699	>	transformer, action).invoke();
3700	>	}
3701
3702	<	if (initialCapacity > MAXIMUM_CAPACITY)
3703	<	initialCapacity = MAXIMUM_CAPACITY;
3704	<	int c = initialCapacity / ssize;
3705	<	if (c * ssize < initialCapacity)
3706	<	++c;
3707	<	int cap = 1;
3708	<	while (cap < c)
3709	<	cap <<= 1;
3702	>	/**
3703	>	* Returns a non-null result from applying the given search
3704	>	* function on each (key, value), or null if none.  Upon
3705	>	* success, further element processing is suppressed and the
3706	>	* results of any other parallel invocations of the search
3707	>	* function are ignored.
3708	>	*
3709	>	* @param parallelismThreshold the (estimated) number of elements
3710	>	* needed for this operation to be executed in parallel
3711	>	* @param searchFunction a function returning a non-null
3712	>	* result on success, else null
3713	>	* @param <U> the return type of the search function
3714	>	* @return a non-null result from applying the given search
3715	>	* function on each (key, value), or null if none
3716	>	* @since 1.8
3717	>	*/
3718	>	public <U> U search(long parallelismThreshold,
3719	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3720	>	if (searchFunction == null) throw new NullPointerException();
3721	>	return new SearchMappingsTask<K,V,U>
3722	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3723	>	searchFunction, new AtomicReference<U>()).invoke();
3724	>	}
3725
3726	<	for (int i = 0; i < this.segments.length; ++i)
3727	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
3726	>	/**
3727	>	* Returns the result of accumulating the given transformation
3728	>	* of all (key, value) pairs using the given reducer to
3729	>	* combine values, or null if none.
3730	>	*
3731	>	* @param parallelismThreshold the (estimated) number of elements
3732	>	* needed for this operation to be executed in parallel
3733	>	* @param transformer a function returning the transformation
3734	>	* for an element, or null if there is no transformation (in
3735	>	* which case it is not combined)
3736	>	* @param reducer a commutative associative combining function
3737	>	* @param <U> the return type of the transformer
3738	>	* @return the result of accumulating the given transformation
3739	>	* of all (key, value) pairs
3740	>	* @since 1.8
3741	>	*/
3742	>	public <U> U reduce(long parallelismThreshold,
3743	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3744	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3745	>	if (transformer == null || reducer == null)
3746	>	throw new NullPointerException();
3747	>	return new MapReduceMappingsTask<K,V,U>
3748	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3749	>	null, transformer, reducer).invoke();
3750		}
3751
3752		/**
3753	<	* Constructs a new, empty map with the specified initial
3754	<	* capacity,  and with default load factor and segments.
3753	>	* Returns the result of accumulating the given transformation
3754	>	* of all (key, value) pairs using the given reducer to
3755	>	* combine values, and the given basis as an identity value.
3756		*
3757	<	* @param initialCapacity the initial capacity of the
3758	<	* ConcurrentHashMap.
3759	<	* @throws IllegalArgumentException if the initial capacity of
3760	<	* elements is negative.
3757	>	* @param parallelismThreshold the (estimated) number of elements
3758	>	* needed for this operation to be executed in parallel
3759	>	* @param transformer a function returning the transformation
3760	>	* for an element
3761	>	* @param basis the identity (initial default value) for the reduction
3762	>	* @param reducer a commutative associative combining function
3763	>	* @return the result of accumulating the given transformation
3764	>	* of all (key, value) pairs
3765	>	* @since 1.8
3766		*/
3767	<	public ConcurrentHashMap(int initialCapacity) {
3768	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3767	>	public double reduceToDouble(long parallelismThreshold,
3768	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3769	>	double basis,
3770	>	DoubleBinaryOperator reducer) {
3771	>	if (transformer == null || reducer == null)
3772	>	throw new NullPointerException();
3773	>	return new MapReduceMappingsToDoubleTask<K,V>
3774	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3775	>	null, transformer, basis, reducer).invoke();
3776		}
3777
3778		/**
3779	<	* Constructs a new, empty map with a default initial capacity,
3780	<	* load factor, and number of segments
3779	>	* Returns the result of accumulating the given transformation
3780	>	* of all (key, value) pairs using the given reducer to
3781	>	* combine values, and the given basis as an identity value.
3782	>	*
3783	>	* @param parallelismThreshold the (estimated) number of elements
3784	>	* needed for this operation to be executed in parallel
3785	>	* @param transformer a function returning the transformation
3786	>	* for an element
3787	>	* @param basis the identity (initial default value) for the reduction
3788	>	* @param reducer a commutative associative combining function
3789	>	* @return the result of accumulating the given transformation
3790	>	* of all (key, value) pairs
3791	>	* @since 1.8
3792		*/
3793	<	public ConcurrentHashMap() {
3794	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3793	>	public long reduceToLong(long parallelismThreshold,
3794	>	ToLongBiFunction<? super K, ? super V> transformer,
3795	>	long basis,
3796	>	LongBinaryOperator reducer) {
3797	>	if (transformer == null || reducer == null)
3798	>	throw new NullPointerException();
3799	>	return new MapReduceMappingsToLongTask<K,V>
3800	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3801	>	null, transformer, basis, reducer).invoke();
3802		}
3803
3804		/**
3805	<	* Constructs a new map with the same mappings as the given map.  The
3806	<	* map is created with a capacity of twice the number of mappings in
3807	<	* the given map or 11 (whichever is greater), and a default load factor.
3805	>	* Returns the result of accumulating the given transformation
3806	>	* of all (key, value) pairs using the given reducer to
3807	>	* combine values, and the given basis as an identity value.
3808	>	*
3809	>	* @param parallelismThreshold the (estimated) number of elements
3810	>	* needed for this operation to be executed in parallel
3811	>	* @param transformer a function returning the transformation
3812	>	* for an element
3813	>	* @param basis the identity (initial default value) for the reduction
3814	>	* @param reducer a commutative associative combining function
3815	>	* @return the result of accumulating the given transformation
3816	>	* of all (key, value) pairs
3817	>	* @since 1.8
3818		*/
3819	<	public <A extends K, B extends V> ConcurrentHashMap(Map<A,B> t) {
3820	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
3821	<	11),
3822	<	DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3823	<	putAll(t);
3819	>	public int reduceToInt(long parallelismThreshold,
3820	>	ToIntBiFunction<? super K, ? super V> transformer,
3821	>	int basis,
3822	>	IntBinaryOperator reducer) {
3823	>	if (transformer == null || reducer == null)
3824	>	throw new NullPointerException();
3825	>	return new MapReduceMappingsToIntTask<K,V>
3826	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3827	>	null, transformer, basis, reducer).invoke();
3828		}
3829
3830	<	// inherit Map javadoc
3831	<	public int size() {
3832	<	int c = 0;
3833	<	for (int i = 0; i < segments.length; ++i)
3834	<	c += segments[i].count;
3835	<	return c;
3830	>	/**
3831	>	* Performs the given action for each key.
3832	>	*
3833	>	* @param parallelismThreshold the (estimated) number of elements
3834	>	* needed for this operation to be executed in parallel
3835	>	* @param action the action
3836	>	* @since 1.8
3837	>	*/
3838	>	public void forEachKey(long parallelismThreshold,
3839	>	Consumer<? super K> action) {
3840	>	if (action == null) throw new NullPointerException();
3841	>	new ForEachKeyTask<K,V>
3842	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3843	>	action).invoke();
3844		}
3845
3846	<	// inherit Map javadoc
3847	<	public boolean isEmpty() {
3848	<	for (int i = 0; i < segments.length; ++i)
3849	<	if (segments[i].count != 0)
3850	<	return false;
3851	<	return true;
3846	>	/**
3847	>	* Performs the given action for each non-null transformation
3848	>	* of each key.
3849	>	*
3850	>	* @param parallelismThreshold the (estimated) number of elements
3851	>	* needed for this operation to be executed in parallel
3852	>	* @param transformer a function returning the transformation
3853	>	* for an element, or null if there is no transformation (in
3854	>	* which case the action is not applied)
3855	>	* @param action the action
3856	>	* @param <U> the return type of the transformer
3857	>	* @since 1.8
3858	>	*/
3859	>	public <U> void forEachKey(long parallelismThreshold,
3860	>	Function<? super K, ? extends U> transformer,
3861	>	Consumer<? super U> action) {
3862	>	if (transformer == null || action == null)
3863	>	throw new NullPointerException();
3864	>	new ForEachTransformedKeyTask<K,V,U>
3865	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3866	>	transformer, action).invoke();
3867		}
3868
3869		/**
3870	<	* Returns the value to which the specified key is mapped in this table.
3870	>	* Returns a non-null result from applying the given search
3871	>	* function on each key, or null if none. Upon success,
3872	>	* further element processing is suppressed and the results of
3873	>	* any other parallel invocations of the search function are
3874	>	* ignored.
3875		*
3876	<	* @param   key   a key in the table.
3877	<	* @return  the value to which the key is mapped in this table;
3878	<	*          <code>null</code> if the key is not mapped to any value in
3879	<	*          this table.
3880	<	* @exception  NullPointerException  if the key is
3881	<	*               <code>null</code>.
3882	<	* @see     #put(Object, Object)
3883	<	*/
3884	<	public V get(K key) {
3885	<	int hash = hash(key); // throws NullPointerException if key null
3886	<	return segmentFor(hash).get(key, segmentHashFor(hash));
3876	>	* @param parallelismThreshold the (estimated) number of elements
3877	>	* needed for this operation to be executed in parallel
3878	>	* @param searchFunction a function returning a non-null
3879	>	* result on success, else null
3880	>	* @param <U> the return type of the search function
3881	>	* @return a non-null result from applying the given search
3882	>	* function on each key, or null if none
3883	>	* @since 1.8
3884	>	*/
3885	>	public <U> U searchKeys(long parallelismThreshold,
3886	>	Function<? super K, ? extends U> searchFunction) {
3887	>	if (searchFunction == null) throw new NullPointerException();
3888	>	return new SearchKeysTask<K,V,U>
3889	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3890	>	searchFunction, new AtomicReference<U>()).invoke();
3891		}
3892
3893		/**
3894	<	* Tests if the specified object is a key in this table.
3895	<	*
3896	<	* @param   key   possible key.
3897	<	* @return  <code>true</code> if and only if the specified object
3898	<	*          is a key in this table, as determined by the
3899	<	*          <tt>equals</tt> method; <code>false</code> otherwise.
3900	<	* @exception  NullPointerException  if the key is
3901	<	*               <code>null</code>.
3902	<	* @see     #contains(Object)
3894	>	* Returns the result of accumulating all keys using the given
3895	>	* reducer to combine values, or null if none.
3896	>	*
3897	>	* @param parallelismThreshold the (estimated) number of elements
3898	>	* needed for this operation to be executed in parallel
3899	>	* @param reducer a commutative associative combining function
3900	>	* @return the result of accumulating all keys using the given
3901	>	* reducer to combine values, or null if none
3902	>	* @since 1.8
3903		*/
3904	<	public boolean containsKey(Object key) {
3905	<	int hash = hash(key); // throws NullPointerException if key null
3906	<	return segmentFor(hash).containsKey(key, segmentHashFor(hash));
3904	>	public K reduceKeys(long parallelismThreshold,
3905	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3906	>	if (reducer == null) throw new NullPointerException();
3907	>	return new ReduceKeysTask<K,V>
3908	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3909	>	null, reducer).invoke();
3910		}
3911
3912		/**
3913	<	* Returns <tt>true</tt> if this map maps one or more keys to the
3914	<	* specified value. Note: This method requires a full internal
3915	<	* traversal of the hash table, and so is much slower than
609	<	* method <tt>containsKey</tt>.
3913	>	* Returns the result of accumulating the given transformation
3914	>	* of all keys using the given reducer to combine values, or
3915	>	* null if none.
3916		*
3917	<	* @param value value whose presence in this map is to be tested.
3918	<	* @return <tt>true</tt> if this map maps one or more keys to the
3919	<	* specified value.
3920	<	* @exception  NullPointerException  if the value is <code>null</code>.
3917	>	* @param parallelismThreshold the (estimated) number of elements
3918	>	* needed for this operation to be executed in parallel
3919	>	* @param transformer a function returning the transformation
3920	>	* for an element, or null if there is no transformation (in
3921	>	* which case it is not combined)
3922	>	* @param reducer a commutative associative combining function
3923	>	* @param <U> the return type of the transformer
3924	>	* @return the result of accumulating the given transformation
3925	>	* of all keys
3926	>	* @since 1.8
3927		*/
3928	<	public boolean containsValue(Object value) {
3929	<	if (value == null)
3928	>	public <U> U reduceKeys(long parallelismThreshold,
3929	>	Function<? super K, ? extends U> transformer,
3930	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3931	>	if (transformer == null || reducer == null)
3932		throw new NullPointerException();
3933	<
3934	<	for (int i = 0; i < segments.length; ++i) {
3935	<	if (segments[i].containsValue(value))
622	<	return true;
623	<	}
624	<	return false;
3933	>	return new MapReduceKeysTask<K,V,U>
3934	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3935	>	null, transformer, reducer).invoke();
3936		}
3937	+
3938		/**
3939	<	* Tests if some key maps into the specified value in this table.
3940	<	* This operation is more expensive than the <code>containsKey</code>
3941	<	* method.<p>
3939	>	* Returns the result of accumulating the given transformation
3940	>	* of all keys using the given reducer to combine values, and
3941	>	* the given basis as an identity value.
3942		*
3943	<	* Note that this method is identical in functionality to containsValue,
3944	<	* (which is part of the Map interface in the collections framework).
3945	<	*
3946	<	* @param      value   a value to search for.
3947	<	* @return     <code>true</code> if and only if some key maps to the
3948	<	*             <code>value</code> argument in this table as
3949	<	*             determined by the <tt>equals</tt> method;
3950	<	*             <code>false</code> otherwise.
3951	<	* @exception  NullPointerException  if the value is <code>null</code>.
640	<	* @see        #containsKey(Object)
641	<	* @see        #containsValue(Object)
642	<	* @see        Map
3943	>	* @param parallelismThreshold the (estimated) number of elements
3944	>	* needed for this operation to be executed in parallel
3945	>	* @param transformer a function returning the transformation
3946	>	* for an element
3947	>	* @param basis the identity (initial default value) for the reduction
3948	>	* @param reducer a commutative associative combining function
3949	>	* @return the result of accumulating the given transformation
3950	>	* of all keys
3951	>	* @since 1.8
3952		*/
3953	<	public boolean contains(Object value) {
3954	<	return containsValue(value);
3953	>	public double reduceKeysToDouble(long parallelismThreshold,
3954	>	ToDoubleFunction<? super K> transformer,
3955	>	double basis,
3956	>	DoubleBinaryOperator reducer) {
3957	>	if (transformer == null || reducer == null)
3958	>	throw new NullPointerException();
3959	>	return new MapReduceKeysToDoubleTask<K,V>
3960	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3961	>	null, transformer, basis, reducer).invoke();
3962		}
3963
3964		/**
3965	<	* Maps the specified <code>key</code> to the specified
3966	<	* <code>value</code> in this table. Neither the key nor the
3967	<	* value can be <code>null</code>. <p>
3968	<	*
3969	<	* The value can be retrieved by calling the <code>get</code> method
3970	<	* with a key that is equal to the original key.
3971	<	*
3972	<	* @param      key     the table key.
3973	<	* @param      value   the value.
3974	<	* @return     the previous value of the specified key in this table,
3975	<	*             or <code>null</code> if it did not have one.
3976	<	* @exception  NullPointerException  if the key or value is
3977	<	*               <code>null</code>.
3978	<	* @see     Object#equals(Object)
3979	<	* @see     #get(Object)
3980	<	*/
3981	<	public V put(K key, V value) {
3982	<	if (value == null)
3983	<	throw new NullPointerException();
3984	<	int hash = hash(key);
3985	<	return segmentFor(hash).put(key, segmentHashFor(hash), value, false);
3965	>	* Returns the result of accumulating the given transformation
3966	>	* of all keys using the given reducer to combine values, and
3967	>	* the given basis as an identity value.
3968	>	*
3969	>	* @param parallelismThreshold the (estimated) number of elements
3970	>	* needed for this operation to be executed in parallel
3971	>	* @param transformer a function returning the transformation
3972	>	* for an element
3973	>	* @param basis the identity (initial default value) for the reduction
3974	>	* @param reducer a commutative associative combining function
3975	>	* @return the result of accumulating the given transformation
3976	>	* of all keys
3977	>	* @since 1.8
3978	>	*/
3979	>	public long reduceKeysToLong(long parallelismThreshold,
3980	>	ToLongFunction<? super K> transformer,
3981	>	long basis,
3982	>	LongBinaryOperator reducer) {
3983	>	if (transformer == null || reducer == null)
3984	>	throw new NullPointerException();
3985	>	return new MapReduceKeysToLongTask<K,V>
3986	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3987	>	null, transformer, basis, reducer).invoke();
3988		}
3989
3990		/**
3991	<	* If the specified key is not already associated
3992	<	* with a value, associate it with the given value.
3993	<	* This is equivalent to
3994	<	* <pre>
3995	<	*   if (!map.containsKey(key)) map.put(key, value);
3996	<	*   return get(key);
3997	<	* </pre>
3998	<	* Except that the action is performed atomically.
3999	<	* @param key key with which the specified value is to be associated.
4000	<	* @param value value to be associated with the specified key.
4001	<	* @return previous value associated with specified key, or <tt>null</tt>
4002	<	*         if there was no mapping for key.  A <tt>null</tt> return can
4003	<	*         also indicate that the map previously associated <tt>null</tt>
4004	<	*         with the specified key, if the implementation supports
4005	<	*         <tt>null</tt> values.
4006	<	*
4007	<	* @throws NullPointerException this map does not permit <tt>null</tt>
4008	<	*            keys or values, and the specified key or value is
4009	<	*            <tt>null</tt>.
692	<	*
693	<	**/
694	<	public V putIfAbsent(K key, V value) {
695	<	if (value == null)
3991	>	* Returns the result of accumulating the given transformation
3992	>	* of all keys using the given reducer to combine values, and
3993	>	* the given basis as an identity value.
3994	>	*
3995	>	* @param parallelismThreshold the (estimated) number of elements
3996	>	* needed for this operation to be executed in parallel
3997	>	* @param transformer a function returning the transformation
3998	>	* for an element
3999	>	* @param basis the identity (initial default value) for the reduction
4000	>	* @param reducer a commutative associative combining function
4001	>	* @return the result of accumulating the given transformation
4002	>	* of all keys
4003	>	* @since 1.8
4004	>	*/
4005	>	public int reduceKeysToInt(long parallelismThreshold,
4006	>	ToIntFunction<? super K> transformer,
4007	>	int basis,
4008	>	IntBinaryOperator reducer) {
4009	>	if (transformer == null || reducer == null)
4010		throw new NullPointerException();
4011	<	int hash = hash(key);
4012	<	return segmentFor(hash).put(key, segmentHashFor(hash), value, true);
4011	>	return new MapReduceKeysToIntTask<K,V>
4012	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4013	>	null, transformer, basis, reducer).invoke();
4014		}
4015
4016	+	/**
4017	+	* Performs the given action for each value.
4018	+	*
4019	+	* @param parallelismThreshold the (estimated) number of elements
4020	+	* needed for this operation to be executed in parallel
4021	+	* @param action the action
4022	+	* @since 1.8
4023	+	*/
4024	+	public void forEachValue(long parallelismThreshold,
4025	+	Consumer<? super V> action) {
4026	+	if (action == null)
4027	+	throw new NullPointerException();
4028	+	new ForEachValueTask<K,V>
4029	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4030	+	action).invoke();
4031	+	}
4032
4033		/**
4034	<	* Copies all of the mappings from the specified map to this one.
4034	>	* Performs the given action for each non-null transformation
4035	>	* of each value.
4036		*
4037	<	* These mappings replace any mappings that this map had for any of the
4038	<	* keys currently in the specified Map.
4037	>	* @param parallelismThreshold the (estimated) number of elements
4038	>	* needed for this operation to be executed in parallel
4039	>	* @param transformer a function returning the transformation
4040	>	* for an element, or null if there is no transformation (in
4041	>	* which case the action is not applied)
4042	>	* @param action the action
4043	>	* @param <U> the return type of the transformer
4044	>	* @since 1.8
4045	>	*/
4046	>	public <U> void forEachValue(long parallelismThreshold,
4047	>	Function<? super V, ? extends U> transformer,
4048	>	Consumer<? super U> action) {
4049	>	if (transformer == null || action == null)
4050	>	throw new NullPointerException();
4051	>	new ForEachTransformedValueTask<K,V,U>
4052	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4053	>	transformer, action).invoke();
4054	>	}
4055	>
4056	>	/**
4057	>	* Returns a non-null result from applying the given search
4058	>	* function on each value, or null if none.  Upon success,
4059	>	* further element processing is suppressed and the results of
4060	>	* any other parallel invocations of the search function are
4061	>	* ignored.
4062		*
4063	<	* @param t Mappings to be stored in this map.
4063	>	* @param parallelismThreshold the (estimated) number of elements
4064	>	* needed for this operation to be executed in parallel
4065	>	* @param searchFunction a function returning a non-null
4066	>	* result on success, else null
4067	>	* @param <U> the return type of the search function
4068	>	* @return a non-null result from applying the given search
4069	>	* function on each value, or null if none
4070	>	* @since 1.8
4071		*/
4072	<	public <K1 extends K, V1 extends V> void putAll(Map<K1,V1> t) {
4073	<	Iterator<Map.Entry<K1,V1>> it = t.entrySet().iterator();
4074	<	while (it.hasNext()) {
4075	<	Entry<K,V> e = (Entry) it.next();
4076	<	put(e.getKey(), e.getValue());
4077	<	}
4072	>	public <U> U searchValues(long parallelismThreshold,
4073	>	Function<? super V, ? extends U> searchFunction) {
4074	>	if (searchFunction == null) throw new NullPointerException();
4075	>	return new SearchValuesTask<K,V,U>
4076	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4077	>	searchFunction, new AtomicReference<U>()).invoke();
4078		}
4079
4080		/**
4081	<	* Removes the key (and its corresponding value) from this
4082	<	* table. This method does nothing if the key is not in the table.
4081	>	* Returns the result of accumulating all values using the
4082	>	* given reducer to combine values, or null if none.
4083		*
4084	<	* @param   key   the key that needs to be removed.
4085	<	* @return  the value to which the key had been mapped in this table,
4086	<	*          or <code>null</code> if the key did not have a mapping.
4087	<	* @exception  NullPointerException  if the key is
4088	<	*               <code>null</code>.
4084	>	* @param parallelismThreshold the (estimated) number of elements
4085	>	* needed for this operation to be executed in parallel
4086	>	* @param reducer a commutative associative combining function
4087	>	* @return the result of accumulating all values
4088	>	* @since 1.8
4089		*/
4090	<	public V remove(Object key) {
4091	<	int hash = hash(key);
4092	<	return segmentFor(hash).remove(key, segmentHashFor(hash), null);
4090	>	public V reduceValues(long parallelismThreshold,
4091	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4092	>	if (reducer == null) throw new NullPointerException();
4093	>	return new ReduceValuesTask<K,V>
4094	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4095	>	null, reducer).invoke();
4096		}
4097
4098		/**
4099	<	* Removes the (key, value) pair from this
4100	<	* table. This method does nothing if the key is not in the table,
4101	<	* or if the key is associated with a different value.
4099	>	* Returns the result of accumulating the given transformation
4100	>	* of all values using the given reducer to combine values, or
4101	>	* null if none.
4102		*
4103	<	* @param   key   the key that needs to be removed.
4104	<	* @param   value   the associated value. If the value is null,
4105	<	*                   it means "any value".
4106	<	* @return  the value to which the key had been mapped in this table,
4107	<	*          or <code>null</code> if the key did not have a mapping.
4108	<	* @exception  NullPointerException  if the key is
4109	<	*               <code>null</code>.
4103	>	* @param parallelismThreshold the (estimated) number of elements
4104	>	* needed for this operation to be executed in parallel
4105	>	* @param transformer a function returning the transformation
4106	>	* for an element, or null if there is no transformation (in
4107	>	* which case it is not combined)
4108	>	* @param reducer a commutative associative combining function
4109	>	* @param <U> the return type of the transformer
4110	>	* @return the result of accumulating the given transformation
4111	>	* of all values
4112	>	* @since 1.8
4113		*/
4114	<	public V remove(Object key, Object value) {
4115	<	int hash = hash(key);
4116	<	return segmentFor(hash).remove(key, segmentHashFor(hash), value);
4114	>	public <U> U reduceValues(long parallelismThreshold,
4115	>	Function<? super V, ? extends U> transformer,
4116	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4117	>	if (transformer == null || reducer == null)
4118	>	throw new NullPointerException();
4119	>	return new MapReduceValuesTask<K,V,U>
4120	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4121	>	null, transformer, reducer).invoke();
4122		}
4123
4124		/**
4125	<	* Removes all mappings from this map.
4125	>	* Returns the result of accumulating the given transformation
4126	>	* of all values using the given reducer to combine values,
4127	>	* and the given basis as an identity value.
4128	>	*
4129	>	* @param parallelismThreshold the (estimated) number of elements
4130	>	* needed for this operation to be executed in parallel
4131	>	* @param transformer a function returning the transformation
4132	>	* for an element
4133	>	* @param basis the identity (initial default value) for the reduction
4134	>	* @param reducer a commutative associative combining function
4135	>	* @return the result of accumulating the given transformation
4136	>	* of all values
4137	>	* @since 1.8
4138		*/
4139	<	public void clear() {
4140	<	for (int i = 0; i < segments.length; ++i)
4141	<	segments[i].clear();
4139	>	public double reduceValuesToDouble(long parallelismThreshold,
4140	>	ToDoubleFunction<? super V> transformer,
4141	>	double basis,
4142	>	DoubleBinaryOperator reducer) {
4143	>	if (transformer == null || reducer == null)
4144	>	throw new NullPointerException();
4145	>	return new MapReduceValuesToDoubleTask<K,V>
4146	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4147	>	null, transformer, basis, reducer).invoke();
4148		}
4149
4150	+	/**
4151	+	* Returns the result of accumulating the given transformation
4152	+	* of all values using the given reducer to combine values,
4153	+	* and the given basis as an identity value.
4154	+	*
4155	+	* @param parallelismThreshold the (estimated) number of elements
4156	+	* needed for this operation to be executed in parallel
4157	+	* @param transformer a function returning the transformation
4158	+	* for an element
4159	+	* @param basis the identity (initial default value) for the reduction
4160	+	* @param reducer a commutative associative combining function
4161	+	* @return the result of accumulating the given transformation
4162	+	* of all values
4163	+	* @since 1.8
4164	+	*/
4165	+	public long reduceValuesToLong(long parallelismThreshold,
4166	+	ToLongFunction<? super V> transformer,
4167	+	long basis,
4168	+	LongBinaryOperator reducer) {
4169	+	if (transformer == null || reducer == null)
4170	+	throw new NullPointerException();
4171	+	return new MapReduceValuesToLongTask<K,V>
4172	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4173	+	null, transformer, basis, reducer).invoke();
4174	+	}
4175
4176		/**
4177	<	* Returns a shallow copy of this
4178	<	* <tt>ConcurrentHashMap</tt> instance: the keys and
4179	<	* values themselves are not cloned.
4177	>	* Returns the result of accumulating the given transformation
4178	>	* of all values using the given reducer to combine values,
4179	>	* and the given basis as an identity value.
4180		*
4181	<	* @return a shallow copy of this map.
4181	>	* @param parallelismThreshold the (estimated) number of elements
4182	>	* needed for this operation to be executed in parallel
4183	>	* @param transformer a function returning the transformation
4184	>	* for an element
4185	>	* @param basis the identity (initial default value) for the reduction
4186	>	* @param reducer a commutative associative combining function
4187	>	* @return the result of accumulating the given transformation
4188	>	* of all values
4189	>	* @since 1.8
4190		*/
4191	<	public Object clone() {
4192	<	// We cannot call super.clone, since it would share final
4193	<	// segments array, and there's no way to reassign finals.
4191	>	public int reduceValuesToInt(long parallelismThreshold,
4192	>	ToIntFunction<? super V> transformer,
4193	>	int basis,
4194	>	IntBinaryOperator reducer) {
4195	>	if (transformer == null || reducer == null)
4196	>	throw new NullPointerException();
4197	>	return new MapReduceValuesToIntTask<K,V>
4198	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4199	>	null, transformer, basis, reducer).invoke();
4200	>	}
4201
4202	<	float lf = segments[0].loadFactor;
4203	<	int segs = segments.length;
4204	<	int cap = (int)(size() / lf);
4205	<	if (cap < segs) cap = segs;
4206	<	ConcurrentHashMap t = new ConcurrentHashMap(cap, lf, segs);
4207	<	t.putAll(this);
4208	<	return t;
4202	>	/**
4203	>	* Performs the given action for each entry.
4204	>	*
4205	>	* @param parallelismThreshold the (estimated) number of elements
4206	>	* needed for this operation to be executed in parallel
4207	>	* @param action the action
4208	>	* @since 1.8
4209	>	*/
4210	>	public void forEachEntry(long parallelismThreshold,
4211	>	Consumer<? super Map.Entry<K,V>> action) {
4212	>	if (action == null) throw new NullPointerException();
4213	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4214	>	action).invoke();
4215		}
4216
4217		/**
4218	<	* Returns a set view of the keys contained in this map.  The set is
4219	<	* backed by the map, so changes to the map are reflected in the set, and
783	<	* vice-versa.  The set supports element removal, which removes the
784	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
785	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
786	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
787	<	* <tt>addAll</tt> operations.
4218	>	* Performs the given action for each non-null transformation
4219	>	* of each entry.
4220		*
4221	<	* @return a set view of the keys contained in this map.
4221	>	* @param parallelismThreshold the (estimated) number of elements
4222	>	* needed for this operation to be executed in parallel
4223	>	* @param transformer a function returning the transformation
4224	>	* for an element, or null if there is no transformation (in
4225	>	* which case the action is not applied)
4226	>	* @param action the action
4227	>	* @param <U> the return type of the transformer
4228	>	* @since 1.8
4229		*/
4230	<	public Set<K> keySet() {
4231	<	Set<K> ks = keySet;
4232	<	return (ks != null)? ks : (keySet = new KeySet());
4230	>	public <U> void forEachEntry(long parallelismThreshold,
4231	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4232	>	Consumer<? super U> action) {
4233	>	if (transformer == null || action == null)
4234	>	throw new NullPointerException();
4235	>	new ForEachTransformedEntryTask<K,V,U>
4236	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4237	>	transformer, action).invoke();
4238		}
4239
4240	+	/**
4241	+	* Returns a non-null result from applying the given search
4242	+	* function on each entry, or null if none.  Upon success,
4243	+	* further element processing is suppressed and the results of
4244	+	* any other parallel invocations of the search function are
4245	+	* ignored.
4246	+	*
4247	+	* @param parallelismThreshold the (estimated) number of elements
4248	+	* needed for this operation to be executed in parallel
4249	+	* @param searchFunction a function returning a non-null
4250	+	* result on success, else null
4251	+	* @param <U> the return type of the search function
4252	+	* @return a non-null result from applying the given search
4253	+	* function on each entry, or null if none
4254	+	* @since 1.8
4255	+	*/
4256	+	public <U> U searchEntries(long parallelismThreshold,
4257	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4258	+	if (searchFunction == null) throw new NullPointerException();
4259	+	return new SearchEntriesTask<K,V,U>
4260	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4261	+	searchFunction, new AtomicReference<U>()).invoke();
4262	+	}
4263
4264		/**
4265	<	* Returns a collection view of the values contained in this map.  The
4266	<	* collection is backed by the map, so changes to the map are reflected in
800	<	* the collection, and vice-versa.  The collection supports element
801	<	* removal, which removes the corresponding mapping from this map, via the
802	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
803	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
804	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
4265	>	* Returns the result of accumulating all entries using the
4266	>	* given reducer to combine values, or null if none.
4267		*
4268	<	* @return a collection view of the values contained in this map.
4268	>	* @param parallelismThreshold the (estimated) number of elements
4269	>	* needed for this operation to be executed in parallel
4270	>	* @param reducer a commutative associative combining function
4271	>	* @return the result of accumulating all entries
4272	>	* @since 1.8
4273		*/
4274	<	public Collection<V> values() {
4275	<	Collection<V> vs = values;
4276	<	return (vs != null)? vs : (values = new Values());
4274	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4275	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4276	>	if (reducer == null) throw new NullPointerException();
4277	>	return new ReduceEntriesTask<K,V>
4278	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4279	>	null, reducer).invoke();
4280		}
4281
4282	+	/**
4283	+	* Returns the result of accumulating the given transformation
4284	+	* of all entries using the given reducer to combine values,
4285	+	* or null if none.
4286	+	*
4287	+	* @param parallelismThreshold the (estimated) number of elements
4288	+	* needed for this operation to be executed in parallel
4289	+	* @param transformer a function returning the transformation
4290	+	* for an element, or null if there is no transformation (in
4291	+	* which case it is not combined)
4292	+	* @param reducer a commutative associative combining function
4293	+	* @param <U> the return type of the transformer
4294	+	* @return the result of accumulating the given transformation
4295	+	* of all entries
4296	+	* @since 1.8
4297	+	*/
4298	+	public <U> U reduceEntries(long parallelismThreshold,
4299	+	Function<Map.Entry<K,V>, ? extends U> transformer,
4300	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4301	+	if (transformer == null || reducer == null)
4302	+	throw new NullPointerException();
4303	+	return new MapReduceEntriesTask<K,V,U>
4304	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4305	+	null, transformer, reducer).invoke();
4306	+	}
4307
4308		/**
4309	<	* Returns a collection view of the mappings contained in this map.  Each
4310	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
4311	<	* collection is backed by the map, so changes to the map are reflected in
818	<	* the collection, and vice-versa.  The collection supports element
819	<	* removal, which removes the corresponding mapping from the map, via the
820	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
821	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
822	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
4309	>	* Returns the result of accumulating the given transformation
4310	>	* of all entries using the given reducer to combine values,
4311	>	* and the given basis as an identity value.
4312		*
4313	<	* @return a collection view of the mappings contained in this map.
4313	>	* @param parallelismThreshold the (estimated) number of elements
4314	>	* needed for this operation to be executed in parallel
4315	>	* @param transformer a function returning the transformation
4316	>	* for an element
4317	>	* @param basis the identity (initial default value) for the reduction
4318	>	* @param reducer a commutative associative combining function
4319	>	* @return the result of accumulating the given transformation
4320	>	* of all entries
4321	>	* @since 1.8
4322		*/
4323	<	public Set<Map.Entry<K,V>> entrySet() {
4324	<	Set<Map.Entry<K,V>> es = entrySet;
4325	<	return (es != null) ? es : (entrySet = new EntrySet());
4323	>	public double reduceEntriesToDouble(long parallelismThreshold,
4324	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4325	>	double basis,
4326	>	DoubleBinaryOperator reducer) {
4327	>	if (transformer == null || reducer == null)
4328	>	throw new NullPointerException();
4329	>	return new MapReduceEntriesToDoubleTask<K,V>
4330	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4331	>	null, transformer, basis, reducer).invoke();
4332		}
4333
4334	+	/**
4335	+	* Returns the result of accumulating the given transformation
4336	+	* of all entries using the given reducer to combine values,
4337	+	* and the given basis as an identity value.
4338	+	*
4339	+	* @param parallelismThreshold the (estimated) number of elements
4340	+	* needed for this operation to be executed in parallel
4341	+	* @param transformer a function returning the transformation
4342	+	* for an element
4343	+	* @param basis the identity (initial default value) for the reduction
4344	+	* @param reducer a commutative associative combining function
4345	+	* @return the result of accumulating the given transformation
4346	+	* of all entries
4347	+	* @since 1.8
4348	+	*/
4349	+	public long reduceEntriesToLong(long parallelismThreshold,
4350	+	ToLongFunction<Map.Entry<K,V>> transformer,
4351	+	long basis,
4352	+	LongBinaryOperator reducer) {
4353	+	if (transformer == null || reducer == null)
4354	+	throw new NullPointerException();
4355	+	return new MapReduceEntriesToLongTask<K,V>
4356	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4357	+	null, transformer, basis, reducer).invoke();
4358	+	}
4359
4360		/**
4361	<	* Returns an enumeration of the keys in this table.
4361	>	* Returns the result of accumulating the given transformation
4362	>	* of all entries using the given reducer to combine values,
4363	>	* and the given basis as an identity value.
4364		*
4365	<	* @return  an enumeration of the keys in this table.
4366	<	* @see     Enumeration
4367	<	* @see     #elements()
4368	<	* @see     #keySet()
4369	<	* @see     Map
4365	>	* @param parallelismThreshold the (estimated) number of elements
4366	>	* needed for this operation to be executed in parallel
4367	>	* @param transformer a function returning the transformation
4368	>	* for an element
4369	>	* @param basis the identity (initial default value) for the reduction
4370	>	* @param reducer a commutative associative combining function
4371	>	* @return the result of accumulating the given transformation
4372	>	* of all entries
4373	>	* @since 1.8
4374		*/
4375	<	public Enumeration<K> keys() {
4376	<	return new KeyIterator();
4375	>	public int reduceEntriesToInt(long parallelismThreshold,
4376	>	ToIntFunction<Map.Entry<K,V>> transformer,
4377	>	int basis,
4378	>	IntBinaryOperator reducer) {
4379	>	if (transformer == null || reducer == null)
4380	>	throw new NullPointerException();
4381	>	return new MapReduceEntriesToIntTask<K,V>
4382	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4383	>	null, transformer, basis, reducer).invoke();
4384		}
4385
4386	+
4387	+	/* ----------------Views -------------- */
4388	+
4389		/**
4390	<	* Returns an enumeration of the values in this table.
4391	<	* Use the Enumeration methods on the returned object to fetch the elements
4392	<	* sequentially.
4390	>	* Base class for views.
4391	>	*/
4392	>	abstract static class CollectionView<K,V,E>
4393	>	implements Collection<E>, java.io.Serializable {
4394	>	private static final long serialVersionUID = 7249069246763182397L;
4395	>	final ConcurrentHashMap<K,V> map;
4396	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4397	>
4398	>	/**
4399	>	* Returns the map backing this view.
4400	>	*
4401	>	* @return the map backing this view
4402	>	*/
4403	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4404	>
4405	>	/**
4406	>	* Removes all of the elements from this view, by removing all
4407	>	* the mappings from the map backing this view.
4408	>	*/
4409	>	public final void clear()      { map.clear(); }
4410	>	public final int size()        { return map.size(); }
4411	>	public final boolean isEmpty() { return map.isEmpty(); }
4412	>
4413	>	// implementations below rely on concrete classes supplying these
4414	>	// abstract methods
4415	>	/**
4416	>	* Returns an iterator over the elements in this collection.
4417	>	*
4418	>	* <p>The returned iterator is
4419	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4420	>	*
4421	>	* @return an iterator over the elements in this collection
4422	>	*/
4423	>	public abstract Iterator<E> iterator();
4424	>	public abstract boolean contains(Object o);
4425	>	public abstract boolean remove(Object o);
4426	>
4427	>	private static final String oomeMsg = "Required array size too large";
4428	>
4429	>	public final Object[] toArray() {
4430	>	long sz = map.mappingCount();
4431	>	if (sz > MAX_ARRAY_SIZE)
4432	>	throw new OutOfMemoryError(oomeMsg);
4433	>	int n = (int)sz;
4434	>	Object[] r = new Object[n];
4435	>	int i = 0;
4436	>	for (E e : this) {
4437	>	if (i == n) {
4438	>	if (n >= MAX_ARRAY_SIZE)
4439	>	throw new OutOfMemoryError(oomeMsg);
4440	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4441	>	n = MAX_ARRAY_SIZE;
4442	>	else
4443	>	n += (n >>> 1) + 1;
4444	>	r = Arrays.copyOf(r, n);
4445	>	}
4446	>	r[i++] = e;
4447	>	}
4448	>	return (i == n) ? r : Arrays.copyOf(r, i);
4449	>	}
4450	>
4451	>	@SuppressWarnings("unchecked")
4452	>	public final <T> T[] toArray(T[] a) {
4453	>	long sz = map.mappingCount();
4454	>	if (sz > MAX_ARRAY_SIZE)
4455	>	throw new OutOfMemoryError(oomeMsg);
4456	>	int m = (int)sz;
4457	>	T[] r = (a.length >= m) ? a :
4458	>	(T[])java.lang.reflect.Array
4459	>	.newInstance(a.getClass().getComponentType(), m);
4460	>	int n = r.length;
4461	>	int i = 0;
4462	>	for (E e : this) {
4463	>	if (i == n) {
4464	>	if (n >= MAX_ARRAY_SIZE)
4465	>	throw new OutOfMemoryError(oomeMsg);
4466	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4467	>	n = MAX_ARRAY_SIZE;
4468	>	else
4469	>	n += (n >>> 1) + 1;
4470	>	r = Arrays.copyOf(r, n);
4471	>	}
4472	>	r[i++] = (T)e;
4473	>	}
4474	>	if (a == r && i < n) {
4475	>	r[i] = null; // null-terminate
4476	>	return r;
4477	>	}
4478	>	return (i == n) ? r : Arrays.copyOf(r, i);
4479	>	}
4480	>
4481	>	/**
4482	>	* Returns a string representation of this collection.
4483	>	* The string representation consists of the string representations
4484	>	* of the collection's elements in the order they are returned by
4485	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4486	>	* Adjacent elements are separated by the characters {@code ", "}
4487	>	* (comma and space).  Elements are converted to strings as by
4488	>	* {@link String#valueOf(Object)}.
4489	>	*
4490	>	* @return a string representation of this collection
4491	>	*/
4492	>	public final String toString() {
4493	>	StringBuilder sb = new StringBuilder();
4494	>	sb.append('[');
4495	>	Iterator<E> it = iterator();
4496	>	if (it.hasNext()) {
4497	>	for (;;) {
4498	>	Object e = it.next();
4499	>	sb.append(e == this ? "(this Collection)" : e);
4500	>	if (!it.hasNext())
4501	>	break;
4502	>	sb.append(',').append(' ');
4503	>	}
4504	>	}
4505	>	return sb.append(']').toString();
4506	>	}
4507	>
4508	>	public final boolean containsAll(Collection<?> c) {
4509	>	if (c != this) {
4510	>	for (Object e : c) {
4511	>	if (e == null || !contains(e))
4512	>	return false;
4513	>	}
4514	>	}
4515	>	return true;
4516	>	}
4517	>
4518	>	public final boolean removeAll(Collection<?> c) {
4519	>	if (c == null) throw new NullPointerException();
4520	>	boolean modified = false;
4521	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4522	>	if (c.contains(it.next())) {
4523	>	it.remove();
4524	>	modified = true;
4525	>	}
4526	>	}
4527	>	return modified;
4528	>	}
4529	>
4530	>	public final boolean retainAll(Collection<?> c) {
4531	>	if (c == null) throw new NullPointerException();
4532	>	boolean modified = false;
4533	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4534	>	if (!c.contains(it.next())) {
4535	>	it.remove();
4536	>	modified = true;
4537	>	}
4538	>	}
4539	>	return modified;
4540	>	}
4541	>
4542	>	}
4543	>
4544	>	/**
4545	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4546	>	* which additions may optionally be enabled by mapping to a
4547	>	* common value.  This class cannot be directly instantiated.
4548	>	* See {@link #keySet() keySet()},
4549	>	* {@link #keySet(Object) keySet(V)},
4550	>	* {@link #newKeySet() newKeySet()},
4551	>	* {@link #newKeySet(int) newKeySet(int)}.
4552		*
4553	<	* @return  an enumeration of the values in this table.
851	<	* @see     java.util.Enumeration
852	<	* @see     #keys()
853	<	* @see     #values()
854	<	* @see     Map
4553	>	* @since 1.8
4554		*/
4555	<	public Enumeration<V> elements() {
4556	<	return new ValueIterator();
4555	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4556	>	implements Set<K>, java.io.Serializable {
4557	>	private static final long serialVersionUID = 7249069246763182397L;
4558	>	private final V value;
4559	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4560	>	super(map);
4561	>	this.value = value;
4562	>	}
4563	>
4564	>	/**
4565	>	* Returns the default mapped value for additions,
4566	>	* or {@code null} if additions are not supported.
4567	>	*
4568	>	* @return the default mapped value for additions, or {@code null}
4569	>	* if not supported
4570	>	*/
4571	>	public V getMappedValue() { return value; }
4572	>
4573	>	/**
4574	>	* {@inheritDoc}
4575	>	* @throws NullPointerException if the specified key is null
4576	>	*/
4577	>	public boolean contains(Object o) { return map.containsKey(o); }
4578	>
4579	>	/**
4580	>	* Removes the key from this map view, by removing the key (and its
4581	>	* corresponding value) from the backing map.  This method does
4582	>	* nothing if the key is not in the map.
4583	>	*
4584	>	* @param  o the key to be removed from the backing map
4585	>	* @return {@code true} if the backing map contained the specified key
4586	>	* @throws NullPointerException if the specified key is null
4587	>	*/
4588	>	public boolean remove(Object o) { return map.remove(o) != null; }
4589	>
4590	>	/**
4591	>	* @return an iterator over the keys of the backing map
4592	>	*/
4593	>	public Iterator<K> iterator() {
4594	>	Node<K,V>[] t;
4595	>	ConcurrentHashMap<K,V> m = map;
4596	>	int f = (t = m.table) == null ? 0 : t.length;
4597	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4598	>	}
4599	>
4600	>	/**
4601	>	* Adds the specified key to this set view by mapping the key to
4602	>	* the default mapped value in the backing map, if defined.
4603	>	*
4604	>	* @param e key to be added
4605	>	* @return {@code true} if this set changed as a result of the call
4606	>	* @throws NullPointerException if the specified key is null
4607	>	* @throws UnsupportedOperationException if no default mapped value
4608	>	* for additions was provided
4609	>	*/
4610	>	public boolean add(K e) {
4611	>	V v;
4612	>	if ((v = value) == null)
4613	>	throw new UnsupportedOperationException();
4614	>	return map.putVal(e, v, true) == null;
4615	>	}
4616	>
4617	>	/**
4618	>	* Adds all of the elements in the specified collection to this set,
4619	>	* as if by calling {@link #add} on each one.
4620	>	*
4621	>	* @param c the elements to be inserted into this set
4622	>	* @return {@code true} if this set changed as a result of the call
4623	>	* @throws NullPointerException if the collection or any of its
4624	>	* elements are {@code null}
4625	>	* @throws UnsupportedOperationException if no default mapped value
4626	>	* for additions was provided
4627	>	*/
4628	>	public boolean addAll(Collection<? extends K> c) {
4629	>	boolean added = false;
4630	>	V v;
4631	>	if ((v = value) == null)
4632	>	throw new UnsupportedOperationException();
4633	>	for (K e : c) {
4634	>	if (map.putVal(e, v, true) == null)
4635	>	added = true;
4636	>	}
4637	>	return added;
4638	>	}
4639	>
4640	>	public int hashCode() {
4641	>	int h = 0;
4642	>	for (K e : this)
4643	>	h += e.hashCode();
4644	>	return h;
4645	>	}
4646	>
4647	>	public boolean equals(Object o) {
4648	>	Set<?> c;
4649	>	return ((o instanceof Set) &&
4650	>	((c = (Set<?>)o) == this ||
4651	>	(containsAll(c) && c.containsAll(this))));
4652	>	}
4653	>
4654	>	public Spliterator<K> spliterator() {
4655	>	Node<K,V>[] t;
4656	>	ConcurrentHashMap<K,V> m = map;
4657	>	long n = m.sumCount();
4658	>	int f = (t = m.table) == null ? 0 : t.length;
4659	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4660	>	}
4661	>
4662	>	public void forEach(Consumer<? super K> action) {
4663	>	if (action == null) throw new NullPointerException();
4664	>	Node<K,V>[] t;
4665	>	if ((t = map.table) != null) {
4666	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4667	>	for (Node<K,V> p; (p = it.advance()) != null; )
4668	>	action.accept(p.key);
4669	>	}
4670	>	}
4671		}
4672
4673	<	/* ---------------- Iterator Support -------------- */
4674	<
4675	<	private abstract class HashIterator {
4676	<	private int nextSegmentIndex;
4677	<	private int nextTableIndex;
4678	<	private HashEntry<K, V>[] currentTable;
4679	<	private HashEntry<K, V> nextEntry;
4680	<	private HashEntry<K, V> lastReturned;
4681	<
4682	<	private HashIterator() {
4683	<	nextSegmentIndex = segments.length-1;
871	<	nextTableIndex = -1;
872	<	advance();
4673	>	/**
4674	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4675	>	* values, in which additions are disabled. This class cannot be
4676	>	* directly instantiated. See {@link #values()}.
4677	>	*/
4678	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4679	>	implements Collection<V>, java.io.Serializable {
4680	>	private static final long serialVersionUID = 2249069246763182397L;
4681	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4682	>	public final boolean contains(Object o) {
4683	>	return map.containsValue(o);
4684		}
4685
4686	<	public boolean hasMoreElements() { return hasNext(); }
4686	>	public final boolean remove(Object o) {
4687	>	if (o != null) {
4688	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4689	>	if (o.equals(it.next())) {
4690	>	it.remove();
4691	>	return true;
4692	>	}
4693	>	}
4694	>	}
4695	>	return false;
4696	>	}
4697
4698	<	private void advance() {
4699	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
4700	<	return;
4701	<
4702	<	while (nextTableIndex >= 0) {
4703	<	if ( (nextEntry = currentTable[nextTableIndex--]) != null)
4704	<	return;
4698	>	public final Iterator<V> iterator() {
4699	>	ConcurrentHashMap<K,V> m = map;
4700	>	Node<K,V>[] t;
4701	>	int f = (t = m.table) == null ? 0 : t.length;
4702	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4703	>	}
4704	>
4705	>	public final boolean add(V e) {
4706	>	throw new UnsupportedOperationException();
4707	>	}
4708	>	public final boolean addAll(Collection<? extends V> c) {
4709	>	throw new UnsupportedOperationException();
4710	>	}
4711	>
4712	>	public boolean removeIf(Predicate<? super V> filter) {
4713	>	return map.removeValueIf(filter);
4714	>	}
4715	>
4716	>	public Spliterator<V> spliterator() {
4717	>	Node<K,V>[] t;
4718	>	ConcurrentHashMap<K,V> m = map;
4719	>	long n = m.sumCount();
4720	>	int f = (t = m.table) == null ? 0 : t.length;
4721	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4722	>	}
4723	>
4724	>	public void forEach(Consumer<? super V> action) {
4725	>	if (action == null) throw new NullPointerException();
4726	>	Node<K,V>[] t;
4727	>	if ((t = map.table) != null) {
4728	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4729	>	for (Node<K,V> p; (p = it.advance()) != null; )
4730	>	action.accept(p.val);
4731		}
4732	<
4733	<	while (nextSegmentIndex >= 0) {
4734	<	Segment<K,V> seg = segments[nextSegmentIndex--];
4735	<	if (seg.count != 0) {
4736	<	currentTable = seg.table;
4737	<	for (int j = currentTable.length-1; j >= 0; --j) {
4738	<	if ( (nextEntry = currentTable[j]) != null) {
4739	<	nextTableIndex = j-1;
4740	<	return;
4741	<	}
4732	>	}
4733	>	}
4734	>
4735	>	/**
4736	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4737	>	* entries.  This class cannot be directly instantiated. See
4738	>	* {@link #entrySet()}.
4739	>	*/
4740	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4741	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4742	>	private static final long serialVersionUID = 2249069246763182397L;
4743	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4744	>
4745	>	public boolean contains(Object o) {
4746	>	Object k, v, r; Map.Entry<?,?> e;
4747	>	return ((o instanceof Map.Entry) &&
4748	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4749	>	(r = map.get(k)) != null &&
4750	>	(v = e.getValue()) != null &&
4751	>	(v == r || v.equals(r)));
4752	>	}
4753	>
4754	>	public boolean remove(Object o) {
4755	>	Object k, v; Map.Entry<?,?> e;
4756	>	return ((o instanceof Map.Entry) &&
4757	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4758	>	(v = e.getValue()) != null &&
4759	>	map.remove(k, v));
4760	>	}
4761	>
4762	>	/**
4763	>	* @return an iterator over the entries of the backing map
4764	>	*/
4765	>	public Iterator<Map.Entry<K,V>> iterator() {
4766	>	ConcurrentHashMap<K,V> m = map;
4767	>	Node<K,V>[] t;
4768	>	int f = (t = m.table) == null ? 0 : t.length;
4769	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4770	>	}
4771	>
4772	>	public boolean add(Entry<K,V> e) {
4773	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4774	>	}
4775	>
4776	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4777	>	boolean added = false;
4778	>	for (Entry<K,V> e : c) {
4779	>	if (add(e))
4780	>	added = true;
4781	>	}
4782	>	return added;
4783	>	}
4784	>
4785	>	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4786	>	return map.removeEntryIf(filter);
4787	>	}
4788	>
4789	>	public final int hashCode() {
4790	>	int h = 0;
4791	>	Node<K,V>[] t;
4792	>	if ((t = map.table) != null) {
4793	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4794	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4795	>	h += p.hashCode();
4796	>	}
4797	>	}
4798	>	return h;
4799	>	}
4800	>
4801	>	public final boolean equals(Object o) {
4802	>	Set<?> c;
4803	>	return ((o instanceof Set) &&
4804	>	((c = (Set<?>)o) == this ||
4805	>	(containsAll(c) && c.containsAll(this))));
4806	>	}
4807	>
4808	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4809	>	Node<K,V>[] t;
4810	>	ConcurrentHashMap<K,V> m = map;
4811	>	long n = m.sumCount();
4812	>	int f = (t = m.table) == null ? 0 : t.length;
4813	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4814	>	}
4815	>
4816	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4817	>	if (action == null) throw new NullPointerException();
4818	>	Node<K,V>[] t;
4819	>	if ((t = map.table) != null) {
4820	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4821	>	for (Node<K,V> p; (p = it.advance()) != null; )
4822	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4823	>	}
4824	>	}
4825	>
4826	>	}
4827	>
4828	>	// -------------------------------------------------------
4829	>
4830	>	/**
4831	>	* Base class for bulk tasks. Repeats some fields and code from
4832	>	* class Traverser, because we need to subclass CountedCompleter.
4833	>	*/
4834	>	@SuppressWarnings("serial")
4835	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4836	>	Node<K,V>[] tab;        // same as Traverser
4837	>	Node<K,V> next;
4838	>	TableStack<K,V> stack, spare;
4839	>	int index;
4840	>	int baseIndex;
4841	>	int baseLimit;
4842	>	final int baseSize;
4843	>	int batch;              // split control
4844	>
4845	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4846	>	super(par);
4847	>	this.batch = b;
4848	>	this.index = this.baseIndex = i;
4849	>	if ((this.tab = t) == null)
4850	>	this.baseSize = this.baseLimit = 0;
4851	>	else if (par == null)
4852	>	this.baseSize = this.baseLimit = t.length;
4853	>	else {
4854	>	this.baseLimit = f;
4855	>	this.baseSize = par.baseSize;
4856	>	}
4857	>	}
4858	>
4859	>	/**
4860	>	* Same as Traverser version
4861	>	*/
4862	>	final Node<K,V> advance() {
4863	>	Node<K,V> e;
4864	>	if ((e = next) != null)
4865	>	e = e.next;
4866	>	for (;;) {
4867	>	Node<K,V>[] t; int i, n;
4868	>	if (e != null)
4869	>	return next = e;
4870	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4871	>	(n = t.length) <= (i = index) || i < 0)
4872	>	return next = null;
4873	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4874	>	if (e instanceof ForwardingNode) {
4875	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4876	>	e = null;
4877	>	pushState(t, i, n);
4878	>	continue;
4879		}
4880	+	else if (e instanceof TreeBin)
4881	+	e = ((TreeBin<K,V>)e).first;
4882	+	else
4883	+	e = null;
4884		}
4885	+	if (stack != null)
4886	+	recoverState(n);
4887	+	else if ((index = i + baseSize) >= n)
4888	+	index = ++baseIndex;
4889		}
4890		}
4891
4892	<	public boolean hasNext() { return nextEntry != null; }
4892	>	private void pushState(Node<K,V>[] t, int i, int n) {
4893	>	TableStack<K,V> s = spare;
4894	>	if (s != null)
4895	>	spare = s.next;
4896	>	else
4897	>	s = new TableStack<K,V>();
4898	>	s.tab = t;
4899	>	s.length = n;
4900	>	s.index = i;
4901	>	s.next = stack;
4902	>	stack = s;
4903	>	}
4904
4905	<	HashEntry<K,V> nextEntry() {
4906	<	if (nextEntry == null)
4907	<	throw new NoSuchElementException();
4908	<	lastReturned = nextEntry;
4909	<	advance();
4910	<	return lastReturned;
4905	>	private void recoverState(int n) {
4906	>	TableStack<K,V> s; int len;
4907	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4908	>	n = len;
4909	>	index = s.index;
4910	>	tab = s.tab;
4911	>	s.tab = null;
4912	>	TableStack<K,V> next = s.next;
4913	>	s.next = spare; // save for reuse
4914	>	stack = next;
4915	>	spare = s;
4916	>	}
4917	>	if (s == null && (index += baseSize) >= n)
4918	>	index = ++baseIndex;
4919		}
4920	+	}
4921
4922	<	public void remove() {
4923	<	if (lastReturned == null)
4924	<	throw new IllegalStateException();
4925	<	ConcurrentHashMap.this.remove(lastReturned.key);
4926	<	lastReturned = null;
4922	>	/*
4923	>	* Task classes. Coded in a regular but ugly format/style to
4924	>	* simplify checks that each variant differs in the right way from
4925	>	* others. The null screenings exist because compilers cannot tell
4926	>	* that we've already null-checked task arguments, so we force
4927	>	* simplest hoisted bypass to help avoid convoluted traps.
4928	>	*/
4929	>	@SuppressWarnings("serial")
4930	>	static final class ForEachKeyTask<K,V>
4931	>	extends BulkTask<K,V,Void> {
4932	>	final Consumer<? super K> action;
4933	>	ForEachKeyTask
4934	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4935	>	Consumer<? super K> action) {
4936	>	super(p, b, i, f, t);
4937	>	this.action = action;
4938	>	}
4939	>	public final void compute() {
4940	>	final Consumer<? super K> action;
4941	>	if ((action = this.action) != null) {
4942	>	for (int i = baseIndex, f, h; batch > 0 &&
4943	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4944	>	addToPendingCount(1);
4945	>	new ForEachKeyTask<K,V>
4946	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4947	>	action).fork();
4948	>	}
4949	>	for (Node<K,V> p; (p = advance()) != null;)
4950	>	action.accept(p.key);
4951	>	propagateCompletion();
4952	>	}
4953		}
4954		}
4955
4956	<	private class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
4957	<	public K next() { return super.nextEntry().key; }
4958	<	public K nextElement() { return super.nextEntry().key; }
4956	>	@SuppressWarnings("serial")
4957	>	static final class ForEachValueTask<K,V>
4958	>	extends BulkTask<K,V,Void> {
4959	>	final Consumer<? super V> action;
4960	>	ForEachValueTask
4961	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4962	>	Consumer<? super V> action) {
4963	>	super(p, b, i, f, t);
4964	>	this.action = action;
4965	>	}
4966	>	public final void compute() {
4967	>	final Consumer<? super V> action;
4968	>	if ((action = this.action) != null) {
4969	>	for (int i = baseIndex, f, h; batch > 0 &&
4970	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4971	>	addToPendingCount(1);
4972	>	new ForEachValueTask<K,V>
4973	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4974	>	action).fork();
4975	>	}
4976	>	for (Node<K,V> p; (p = advance()) != null;)
4977	>	action.accept(p.val);
4978	>	propagateCompletion();
4979	>	}
4980	>	}
4981		}
4982
4983	<	private class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
4984	<	public V next() { return super.nextEntry().value; }
4985	<	public V nextElement() { return super.nextEntry().value; }
4983	>	@SuppressWarnings("serial")
4984	>	static final class ForEachEntryTask<K,V>
4985	>	extends BulkTask<K,V,Void> {
4986	>	final Consumer<? super Entry<K,V>> action;
4987	>	ForEachEntryTask
4988	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4989	>	Consumer<? super Entry<K,V>> action) {
4990	>	super(p, b, i, f, t);
4991	>	this.action = action;
4992	>	}
4993	>	public final void compute() {
4994	>	final Consumer<? super Entry<K,V>> action;
4995	>	if ((action = this.action) != null) {
4996	>	for (int i = baseIndex, f, h; batch > 0 &&
4997	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4998	>	addToPendingCount(1);
4999	>	new ForEachEntryTask<K,V>
5000	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5001	>	action).fork();
5002	>	}
5003	>	for (Node<K,V> p; (p = advance()) != null; )
5004	>	action.accept(p);
5005	>	propagateCompletion();
5006	>	}
5007	>	}
5008		}
5009
5010	<	private class EntryIterator extends HashIterator implements Iterator<Entry<K,V>> {
5011	<	public Map.Entry<K,V> next() { return super.nextEntry(); }
5010	>	@SuppressWarnings("serial")
5011	>	static final class ForEachMappingTask<K,V>
5012	>	extends BulkTask<K,V,Void> {
5013	>	final BiConsumer<? super K, ? super V> action;
5014	>	ForEachMappingTask
5015	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5016	>	BiConsumer<? super K,? super V> action) {
5017	>	super(p, b, i, f, t);
5018	>	this.action = action;
5019	>	}
5020	>	public final void compute() {
5021	>	final BiConsumer<? super K, ? super V> action;
5022	>	if ((action = this.action) != null) {
5023	>	for (int i = baseIndex, f, h; batch > 0 &&
5024	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5025	>	addToPendingCount(1);
5026	>	new ForEachMappingTask<K,V>
5027	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5028	>	action).fork();
5029	>	}
5030	>	for (Node<K,V> p; (p = advance()) != null; )
5031	>	action.accept(p.key, p.val);
5032	>	propagateCompletion();
5033	>	}
5034	>	}
5035		}
5036
5037	<	private class KeySet extends AbstractSet<K> {
5038	<	public Iterator<K> iterator() {
5039	<	return new KeyIterator();
5037	>	@SuppressWarnings("serial")
5038	>	static final class ForEachTransformedKeyTask<K,V,U>
5039	>	extends BulkTask<K,V,Void> {
5040	>	final Function<? super K, ? extends U> transformer;
5041	>	final Consumer<? super U> action;
5042	>	ForEachTransformedKeyTask
5043	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5044	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5045	>	super(p, b, i, f, t);
5046	>	this.transformer = transformer; this.action = action;
5047		}
5048	<	public int size() {
5049	<	return ConcurrentHashMap.this.size();
5048	>	public final void compute() {
5049	>	final Function<? super K, ? extends U> transformer;
5050	>	final Consumer<? super U> action;
5051	>	if ((transformer = this.transformer) != null &&
5052	>	(action = this.action) != null) {
5053	>	for (int i = baseIndex, f, h; batch > 0 &&
5054	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5055	>	addToPendingCount(1);
5056	>	new ForEachTransformedKeyTask<K,V,U>
5057	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5058	>	transformer, action).fork();
5059	>	}
5060	>	for (Node<K,V> p; (p = advance()) != null; ) {
5061	>	U u;
5062	>	if ((u = transformer.apply(p.key)) != null)
5063	>	action.accept(u);
5064	>	}
5065	>	propagateCompletion();
5066	>	}
5067		}
5068	<	public boolean contains(Object o) {
5069	<	return ConcurrentHashMap.this.containsKey(o);
5068	>	}
5069	>
5070	>	@SuppressWarnings("serial")
5071	>	static final class ForEachTransformedValueTask<K,V,U>
5072	>	extends BulkTask<K,V,Void> {
5073	>	final Function<? super V, ? extends U> transformer;
5074	>	final Consumer<? super U> action;
5075	>	ForEachTransformedValueTask
5076	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5077	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5078	>	super(p, b, i, f, t);
5079	>	this.transformer = transformer; this.action = action;
5080		}
5081	<	public boolean remove(Object o) {
5082	<	return ConcurrentHashMap.this.remove(o) != null;
5081	>	public final void compute() {
5082	>	final Function<? super V, ? extends U> transformer;
5083	>	final Consumer<? super U> action;
5084	>	if ((transformer = this.transformer) != null &&
5085	>	(action = this.action) != null) {
5086	>	for (int i = baseIndex, f, h; batch > 0 &&
5087	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5088	>	addToPendingCount(1);
5089	>	new ForEachTransformedValueTask<K,V,U>
5090	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5091	>	transformer, action).fork();
5092	>	}
5093	>	for (Node<K,V> p; (p = advance()) != null; ) {
5094	>	U u;
5095	>	if ((u = transformer.apply(p.val)) != null)
5096	>	action.accept(u);
5097	>	}
5098	>	propagateCompletion();
5099	>	}
5100		}
5101	<	public void clear() {
5102	<	ConcurrentHashMap.this.clear();
5101	>	}
5102	>
5103	>	@SuppressWarnings("serial")
5104	>	static final class ForEachTransformedEntryTask<K,V,U>
5105	>	extends BulkTask<K,V,Void> {
5106	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5107	>	final Consumer<? super U> action;
5108	>	ForEachTransformedEntryTask
5109	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5110	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5111	>	super(p, b, i, f, t);
5112	>	this.transformer = transformer; this.action = action;
5113	>	}
5114	>	public final void compute() {
5115	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5116	>	final Consumer<? super U> action;
5117	>	if ((transformer = this.transformer) != null &&
5118	>	(action = this.action) != null) {
5119	>	for (int i = baseIndex, f, h; batch > 0 &&
5120	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5121	>	addToPendingCount(1);
5122	>	new ForEachTransformedEntryTask<K,V,U>
5123	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5124	>	transformer, action).fork();
5125	>	}
5126	>	for (Node<K,V> p; (p = advance()) != null; ) {
5127	>	U u;
5128	>	if ((u = transformer.apply(p)) != null)
5129	>	action.accept(u);
5130	>	}
5131	>	propagateCompletion();
5132	>	}
5133		}
5134		}
5135
5136	<	private class Values extends AbstractCollection<V> {
5137	<	public Iterator<V> iterator() {
5138	<	return new ValueIterator();
5136	>	@SuppressWarnings("serial")
5137	>	static final class ForEachTransformedMappingTask<K,V,U>
5138	>	extends BulkTask<K,V,Void> {
5139	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5140	>	final Consumer<? super U> action;
5141	>	ForEachTransformedMappingTask
5142	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5143	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5144	>	Consumer<? super U> action) {
5145	>	super(p, b, i, f, t);
5146	>	this.transformer = transformer; this.action = action;
5147		}
5148	<	public int size() {
5149	<	return ConcurrentHashMap.this.size();
5148	>	public final void compute() {
5149	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5150	>	final Consumer<? super U> action;
5151	>	if ((transformer = this.transformer) != null &&
5152	>	(action = this.action) != null) {
5153	>	for (int i = baseIndex, f, h; batch > 0 &&
5154	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5155	>	addToPendingCount(1);
5156	>	new ForEachTransformedMappingTask<K,V,U>
5157	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5158	>	transformer, action).fork();
5159	>	}
5160	>	for (Node<K,V> p; (p = advance()) != null; ) {
5161	>	U u;
5162	>	if ((u = transformer.apply(p.key, p.val)) != null)
5163	>	action.accept(u);
5164	>	}
5165	>	propagateCompletion();
5166	>	}
5167		}
5168	<	public boolean contains(Object o) {
5169	<	return ConcurrentHashMap.this.containsValue(o);
5168	>	}
5169	>
5170	>	@SuppressWarnings("serial")
5171	>	static final class SearchKeysTask<K,V,U>
5172	>	extends BulkTask<K,V,U> {
5173	>	final Function<? super K, ? extends U> searchFunction;
5174	>	final AtomicReference<U> result;
5175	>	SearchKeysTask
5176	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5177	>	Function<? super K, ? extends U> searchFunction,
5178	>	AtomicReference<U> result) {
5179	>	super(p, b, i, f, t);
5180	>	this.searchFunction = searchFunction; this.result = result;
5181		}
5182	<	public void clear() {
5183	<	ConcurrentHashMap.this.clear();
5182	>	public final U getRawResult() { return result.get(); }
5183	>	public final void compute() {
5184	>	final Function<? super K, ? extends U> searchFunction;
5185	>	final AtomicReference<U> result;
5186	>	if ((searchFunction = this.searchFunction) != null &&
5187	>	(result = this.result) != null) {
5188	>	for (int i = baseIndex, f, h; batch > 0 &&
5189	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5190	>	if (result.get() != null)
5191	>	return;
5192	>	addToPendingCount(1);
5193	>	new SearchKeysTask<K,V,U>
5194	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5195	>	searchFunction, result).fork();
5196	>	}
5197	>	while (result.get() == null) {
5198	>	U u;
5199	>	Node<K,V> p;
5200	>	if ((p = advance()) == null) {
5201	>	propagateCompletion();
5202	>	break;
5203	>	}
5204	>	if ((u = searchFunction.apply(p.key)) != null) {
5205	>	if (result.compareAndSet(null, u))
5206	>	quietlyCompleteRoot();
5207	>	break;
5208	>	}
5209	>	}
5210	>	}
5211		}
5212		}
5213
5214	<	private class EntrySet extends AbstractSet {
5215	<	public Iterator<Map.Entry<K,V>> iterator() {
5216	<	return new EntryIterator();
5214	>	@SuppressWarnings("serial")
5215	>	static final class SearchValuesTask<K,V,U>
5216	>	extends BulkTask<K,V,U> {
5217	>	final Function<? super V, ? extends U> searchFunction;
5218	>	final AtomicReference<U> result;
5219	>	SearchValuesTask
5220	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5221	>	Function<? super V, ? extends U> searchFunction,
5222	>	AtomicReference<U> result) {
5223	>	super(p, b, i, f, t);
5224	>	this.searchFunction = searchFunction; this.result = result;
5225		}
5226	<	public boolean contains(Object o) {
5227	<	if (!(o instanceof Map.Entry))
5228	<	return false;
5229	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5230	<	V v = ConcurrentHashMap.this.get(e.getKey());
5231	<	return v != null && v.equals(e.getValue());
5226	>	public final U getRawResult() { return result.get(); }
5227	>	public final void compute() {
5228	>	final Function<? super V, ? extends U> searchFunction;
5229	>	final AtomicReference<U> result;
5230	>	if ((searchFunction = this.searchFunction) != null &&
5231	>	(result = this.result) != null) {
5232	>	for (int i = baseIndex, f, h; batch > 0 &&
5233	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5234	>	if (result.get() != null)
5235	>	return;
5236	>	addToPendingCount(1);
5237	>	new SearchValuesTask<K,V,U>
5238	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5239	>	searchFunction, result).fork();
5240	>	}
5241	>	while (result.get() == null) {
5242	>	U u;
5243	>	Node<K,V> p;
5244	>	if ((p = advance()) == null) {
5245	>	propagateCompletion();
5246	>	break;
5247	>	}
5248	>	if ((u = searchFunction.apply(p.val)) != null) {
5249	>	if (result.compareAndSet(null, u))
5250	>	quietlyCompleteRoot();
5251	>	break;
5252	>	}
5253	>	}
5254	>	}
5255		}
5256	<	public boolean remove(Object o) {
5257	<	if (!(o instanceof Map.Entry))
5258	<	return false;
5259	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5260	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue()) != null;
5256	>	}
5257	>
5258	>	@SuppressWarnings("serial")
5259	>	static final class SearchEntriesTask<K,V,U>
5260	>	extends BulkTask<K,V,U> {
5261	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5262	>	final AtomicReference<U> result;
5263	>	SearchEntriesTask
5264	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5265	>	Function<Entry<K,V>, ? extends U> searchFunction,
5266	>	AtomicReference<U> result) {
5267	>	super(p, b, i, f, t);
5268	>	this.searchFunction = searchFunction; this.result = result;
5269		}
5270	<	public int size() {
5271	<	return ConcurrentHashMap.this.size();
5270	>	public final U getRawResult() { return result.get(); }
5271	>	public final void compute() {
5272	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5273	>	final AtomicReference<U> result;
5274	>	if ((searchFunction = this.searchFunction) != null &&
5275	>	(result = this.result) != null) {
5276	>	for (int i = baseIndex, f, h; batch > 0 &&
5277	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5278	>	if (result.get() != null)
5279	>	return;
5280	>	addToPendingCount(1);
5281	>	new SearchEntriesTask<K,V,U>
5282	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5283	>	searchFunction, result).fork();
5284	>	}
5285	>	while (result.get() == null) {
5286	>	U u;
5287	>	Node<K,V> p;
5288	>	if ((p = advance()) == null) {
5289	>	propagateCompletion();
5290	>	break;
5291	>	}
5292	>	if ((u = searchFunction.apply(p)) != null) {
5293	>	if (result.compareAndSet(null, u))
5294	>	quietlyCompleteRoot();
5295	>	return;
5296	>	}
5297	>	}
5298	>	}
5299	>	}
5300	>	}
5301	>
5302	>	@SuppressWarnings("serial")
5303	>	static final class SearchMappingsTask<K,V,U>
5304	>	extends BulkTask<K,V,U> {
5305	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5306	>	final AtomicReference<U> result;
5307	>	SearchMappingsTask
5308	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5309	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5310	>	AtomicReference<U> result) {
5311	>	super(p, b, i, f, t);
5312	>	this.searchFunction = searchFunction; this.result = result;
5313		}
5314	<	public void clear() {
5315	<	ConcurrentHashMap.this.clear();
5314	>	public final U getRawResult() { return result.get(); }
5315	>	public final void compute() {
5316	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5317	>	final AtomicReference<U> result;
5318	>	if ((searchFunction = this.searchFunction) != null &&
5319	>	(result = this.result) != null) {
5320	>	for (int i = baseIndex, f, h; batch > 0 &&
5321	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5322	>	if (result.get() != null)
5323	>	return;
5324	>	addToPendingCount(1);
5325	>	new SearchMappingsTask<K,V,U>
5326	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5327	>	searchFunction, result).fork();
5328	>	}
5329	>	while (result.get() == null) {
5330	>	U u;
5331	>	Node<K,V> p;
5332	>	if ((p = advance()) == null) {
5333	>	propagateCompletion();
5334	>	break;
5335	>	}
5336	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5337	>	if (result.compareAndSet(null, u))
5338	>	quietlyCompleteRoot();
5339	>	break;
5340	>	}
5341	>	}
5342	>	}
5343		}
5344		}
5345
5346	<	/* ---------------- Serialization Support -------------- */
5346	>	@SuppressWarnings("serial")
5347	>	static final class ReduceKeysTask<K,V>
5348	>	extends BulkTask<K,V,K> {
5349	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5350	>	K result;
5351	>	ReduceKeysTask<K,V> rights, nextRight;
5352	>	ReduceKeysTask
5353	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5354	>	ReduceKeysTask<K,V> nextRight,
5355	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5356	>	super(p, b, i, f, t); this.nextRight = nextRight;
5357	>	this.reducer = reducer;
5358	>	}
5359	>	public final K getRawResult() { return result; }
5360	>	public final void compute() {
5361	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5362	>	if ((reducer = this.reducer) != null) {
5363	>	for (int i = baseIndex, f, h; batch > 0 &&
5364	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5365	>	addToPendingCount(1);
5366	>	(rights = new ReduceKeysTask<K,V>
5367	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5368	>	rights, reducer)).fork();
5369	>	}
5370	>	K r = null;
5371	>	for (Node<K,V> p; (p = advance()) != null; ) {
5372	>	K u = p.key;
5373	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5374	>	}
5375	>	result = r;
5376	>	CountedCompleter<?> c;
5377	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5378	>	@SuppressWarnings("unchecked")
5379	>	ReduceKeysTask<K,V>
5380	>	t = (ReduceKeysTask<K,V>)c,
5381	>	s = t.rights;
5382	>	while (s != null) {
5383	>	K tr, sr;
5384	>	if ((sr = s.result) != null)
5385	>	t.result = (((tr = t.result) == null) ? sr :
5386	>	reducer.apply(tr, sr));
5387	>	s = t.rights = s.nextRight;
5388	>	}
5389	>	}
5390	>	}
5391	>	}
5392	>	}
5393
5394	<	/**
5395	<	* Save the state of the <tt>ConcurrentHashMap</tt>
5396	<	* instance to a stream (i.e.,
5397	<	* serialize it).
5398	<	* @serialData
5399	<	* the key (Object) and value (Object)
5400	<	* for each key-value mapping, followed by a null pair.
5401	<	* The key-value mappings are emitted in no particular order.
5402	<	*/
5403	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
5404	<	s.defaultWriteObject();
5394	>	@SuppressWarnings("serial")
5395	>	static final class ReduceValuesTask<K,V>
5396	>	extends BulkTask<K,V,V> {
5397	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5398	>	V result;
5399	>	ReduceValuesTask<K,V> rights, nextRight;
5400	>	ReduceValuesTask
5401	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5402	>	ReduceValuesTask<K,V> nextRight,
5403	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5404	>	super(p, b, i, f, t); this.nextRight = nextRight;
5405	>	this.reducer = reducer;
5406	>	}
5407	>	public final V getRawResult() { return result; }
5408	>	public final void compute() {
5409	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5410	>	if ((reducer = this.reducer) != null) {
5411	>	for (int i = baseIndex, f, h; batch > 0 &&
5412	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5413	>	addToPendingCount(1);
5414	>	(rights = new ReduceValuesTask<K,V>
5415	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5416	>	rights, reducer)).fork();
5417	>	}
5418	>	V r = null;
5419	>	for (Node<K,V> p; (p = advance()) != null; ) {
5420	>	V v = p.val;
5421	>	r = (r == null) ? v : reducer.apply(r, v);
5422	>	}
5423	>	result = r;
5424	>	CountedCompleter<?> c;
5425	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5426	>	@SuppressWarnings("unchecked")
5427	>	ReduceValuesTask<K,V>
5428	>	t = (ReduceValuesTask<K,V>)c,
5429	>	s = t.rights;
5430	>	while (s != null) {
5431	>	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	>	}
5441
5442	<	for (int k = 0; k < segments.length; ++k) {
5443	<	Segment<K,V> seg = segments[k];
5444	<	seg.lock();
5445	<	try {
5446	<	HashEntry<K,V>[] tab = seg.table;
5447	<	for (int i = 0; i < tab.length; ++i) {
5448	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
5449	<	s.writeObject(e.key);
5450	<	s.writeObject(e.value);
5442	>	@SuppressWarnings("serial")
5443	>	static final class ReduceEntriesTask<K,V>
5444	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5445	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5446	>	Map.Entry<K,V> result;
5447	>	ReduceEntriesTask<K,V> rights, nextRight;
5448	>	ReduceEntriesTask
5449	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5450	>	ReduceEntriesTask<K,V> nextRight,
5451	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5452	>	super(p, b, i, f, t); this.nextRight = nextRight;
5453	>	this.reducer = reducer;
5454	>	}
5455	>	public final Map.Entry<K,V> getRawResult() { return result; }
5456	>	public final void compute() {
5457	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5458	>	if ((reducer = this.reducer) != null) {
5459	>	for (int i = baseIndex, f, h; batch > 0 &&
5460	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5461	>	addToPendingCount(1);
5462	>	(rights = new ReduceEntriesTask<K,V>
5463	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5464	>	rights, reducer)).fork();
5465	>	}
5466	>	Map.Entry<K,V> r = null;
5467	>	for (Node<K,V> p; (p = advance()) != null; )
5468	>	r = (r == null) ? p : reducer.apply(r, p);
5469	>	result = r;
5470	>	CountedCompleter<?> c;
5471	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5472	>	@SuppressWarnings("unchecked")
5473	>	ReduceEntriesTask<K,V>
5474	>	t = (ReduceEntriesTask<K,V>)c,
5475	>	s = t.rights;
5476	>	while (s != null) {
5477	>	Map.Entry<K,V> tr, sr;
5478	>	if ((sr = s.result) != null)
5479	>	t.result = (((tr = t.result) == null) ? sr :
5480	>	reducer.apply(tr, sr));
5481	>	s = t.rights = s.nextRight;
5482	>	}
5483	>	}
5484	>	}
5485	>	}
5486	>	}
5487	>
5488	>	@SuppressWarnings("serial")
5489	>	static final class MapReduceKeysTask<K,V,U>
5490	>	extends BulkTask<K,V,U> {
5491	>	final Function<? super K, ? extends U> transformer;
5492	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5493	>	U result;
5494	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5495	>	MapReduceKeysTask
5496	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5497	>	MapReduceKeysTask<K,V,U> nextRight,
5498	>	Function<? super K, ? extends U> transformer,
5499	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5500	>	super(p, b, i, f, t); this.nextRight = nextRight;
5501	>	this.transformer = transformer;
5502	>	this.reducer = reducer;
5503	>	}
5504	>	public final U getRawResult() { return result; }
5505	>	public final void compute() {
5506	>	final Function<? super K, ? extends U> transformer;
5507	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5508	>	if ((transformer = this.transformer) != null &&
5509	>	(reducer = this.reducer) != null) {
5510	>	for (int i = baseIndex, f, h; batch > 0 &&
5511	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5512	>	addToPendingCount(1);
5513	>	(rights = new MapReduceKeysTask<K,V,U>
5514	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5515	>	rights, transformer, reducer)).fork();
5516	>	}
5517	>	U r = null;
5518	>	for (Node<K,V> p; (p = advance()) != null; ) {
5519	>	U u;
5520	>	if ((u = transformer.apply(p.key)) != null)
5521	>	r = (r == null) ? u : reducer.apply(r, u);
5522	>	}
5523	>	result = r;
5524	>	CountedCompleter<?> c;
5525	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5526	>	@SuppressWarnings("unchecked")
5527	>	MapReduceKeysTask<K,V,U>
5528	>	t = (MapReduceKeysTask<K,V,U>)c,
5529	>	s = t.rights;
5530	>	while (s != null) {
5531	>	U tr, sr;
5532	>	if ((sr = s.result) != null)
5533	>	t.result = (((tr = t.result) == null) ? sr :
5534	>	reducer.apply(tr, sr));
5535	>	s = t.rights = s.nextRight;
5536		}
5537		}
5538		}
5539	<	finally {
5540	<	seg.unlock();
5539	>	}
5540	>	}
5541	>
5542	>	@SuppressWarnings("serial")
5543	>	static final class MapReduceValuesTask<K,V,U>
5544	>	extends BulkTask<K,V,U> {
5545	>	final Function<? super V, ? extends U> transformer;
5546	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5547	>	U result;
5548	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5549	>	MapReduceValuesTask
5550	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5551	>	MapReduceValuesTask<K,V,U> nextRight,
5552	>	Function<? super V, ? extends U> transformer,
5553	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5554	>	super(p, b, i, f, t); this.nextRight = nextRight;
5555	>	this.transformer = transformer;
5556	>	this.reducer = reducer;
5557	>	}
5558	>	public final U getRawResult() { return result; }
5559	>	public final void compute() {
5560	>	final Function<? super V, ? extends U> transformer;
5561	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5562	>	if ((transformer = this.transformer) != null &&
5563	>	(reducer = this.reducer) != null) {
5564	>	for (int i = baseIndex, f, h; batch > 0 &&
5565	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5566	>	addToPendingCount(1);
5567	>	(rights = new MapReduceValuesTask<K,V,U>
5568	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5569	>	rights, transformer, reducer)).fork();
5570	>	}
5571	>	U r = null;
5572	>	for (Node<K,V> p; (p = advance()) != null; ) {
5573	>	U u;
5574	>	if ((u = transformer.apply(p.val)) != null)
5575	>	r = (r == null) ? u : reducer.apply(r, u);
5576	>	}
5577	>	result = r;
5578	>	CountedCompleter<?> c;
5579	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5580	>	@SuppressWarnings("unchecked")
5581	>	MapReduceValuesTask<K,V,U>
5582	>	t = (MapReduceValuesTask<K,V,U>)c,
5583	>	s = t.rights;
5584	>	while (s != null) {
5585	>	U tr, sr;
5586	>	if ((sr = s.result) != null)
5587	>	t.result = (((tr = t.result) == null) ? sr :
5588	>	reducer.apply(tr, sr));
5589	>	s = t.rights = s.nextRight;
5590	>	}
5591	>	}
5592		}
5593		}
1020	–	s.writeObject(null);
1021	–	s.writeObject(null);
5594		}
5595
5596	<	/**
5597	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
5598	<	* instance from a stream (i.e.,
5599	<	* deserialize it).
5600	<	*/
5601	<	private void readObject(java.io.ObjectInputStream s)
5602	<	throws IOException, ClassNotFoundException  {
5603	<	s.defaultReadObject();
5596	>	@SuppressWarnings("serial")
5597	>	static final class MapReduceEntriesTask<K,V,U>
5598	>	extends BulkTask<K,V,U> {
5599	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5600	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5601	>	U result;
5602	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5603	>	MapReduceEntriesTask
5604	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5605	>	MapReduceEntriesTask<K,V,U> nextRight,
5606	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5607	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5608	>	super(p, b, i, f, t); this.nextRight = nextRight;
5609	>	this.transformer = transformer;
5610	>	this.reducer = reducer;
5611	>	}
5612	>	public final U getRawResult() { return result; }
5613	>	public final void compute() {
5614	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5615	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5616	>	if ((transformer = this.transformer) != null &&
5617	>	(reducer = this.reducer) != null) {
5618	>	for (int i = baseIndex, f, h; batch > 0 &&
5619	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5620	>	addToPendingCount(1);
5621	>	(rights = new MapReduceEntriesTask<K,V,U>
5622	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5623	>	rights, transformer, reducer)).fork();
5624	>	}
5625	>	U r = null;
5626	>	for (Node<K,V> p; (p = advance()) != null; ) {
5627	>	U u;
5628	>	if ((u = transformer.apply(p)) != null)
5629	>	r = (r == null) ? u : reducer.apply(r, u);
5630	>	}
5631	>	result = r;
5632	>	CountedCompleter<?> c;
5633	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5634	>	@SuppressWarnings("unchecked")
5635	>	MapReduceEntriesTask<K,V,U>
5636	>	t = (MapReduceEntriesTask<K,V,U>)c,
5637	>	s = t.rights;
5638	>	while (s != null) {
5639	>	U tr, sr;
5640	>	if ((sr = s.result) != null)
5641	>	t.result = (((tr = t.result) == null) ? sr :
5642	>	reducer.apply(tr, sr));
5643	>	s = t.rights = s.nextRight;
5644	>	}
5645	>	}
5646	>	}
5647	>	}
5648	>	}
5649
5650	<	// Initialize each segment to be minimally sized, and let grow.
5651	<	for (int i = 0; i < segments.length; ++i) {
5652	<	segments[i].setTable(new HashEntry<K,V>[1]);
5650	>	@SuppressWarnings("serial")
5651	>	static final class MapReduceMappingsTask<K,V,U>
5652	>	extends BulkTask<K,V,U> {
5653	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5654	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5655	>	U result;
5656	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5657	>	MapReduceMappingsTask
5658	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5659	>	MapReduceMappingsTask<K,V,U> nextRight,
5660	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5661	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5662	>	super(p, b, i, f, t); this.nextRight = nextRight;
5663	>	this.transformer = transformer;
5664	>	this.reducer = reducer;
5665		}
5666	+	public final U getRawResult() { return result; }
5667	+	public final void compute() {
5668	+	final BiFunction<? super K, ? super V, ? extends U> transformer;
5669	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
5670	+	if ((transformer = this.transformer) != null &&
5671	+	(reducer = this.reducer) != null) {
5672	+	for (int i = baseIndex, f, h; batch > 0 &&
5673	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5674	+	addToPendingCount(1);
5675	+	(rights = new MapReduceMappingsTask<K,V,U>
5676	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5677	+	rights, transformer, reducer)).fork();
5678	+	}
5679	+	U r = null;
5680	+	for (Node<K,V> p; (p = advance()) != null; ) {
5681	+	U u;
5682	+	if ((u = transformer.apply(p.key, p.val)) != null)
5683	+	r = (r == null) ? u : reducer.apply(r, u);
5684	+	}
5685	+	result = r;
5686	+	CountedCompleter<?> c;
5687	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5688	+	@SuppressWarnings("unchecked")
5689	+	MapReduceMappingsTask<K,V,U>
5690	+	t = (MapReduceMappingsTask<K,V,U>)c,
5691	+	s = t.rights;
5692	+	while (s != null) {
5693	+	U tr, sr;
5694	+	if ((sr = s.result) != null)
5695	+	t.result = (((tr = t.result) == null) ? sr :
5696	+	reducer.apply(tr, sr));
5697	+	s = t.rights = s.nextRight;
5698	+	}
5699	+	}
5700	+	}
5701	+	}
5702	+	}
5703
5704	<	// Read the keys and values, and put the mappings in the table
5705	<	while (true) {
5706	<	K key = (K) s.readObject();
5707	<	V value = (V) s.readObject();
5708	<	if (key == null)
5709	<	break;
5710	<	put(key, value);
5704	>	@SuppressWarnings("serial")
5705	>	static final class MapReduceKeysToDoubleTask<K,V>
5706	>	extends BulkTask<K,V,Double> {
5707	>	final ToDoubleFunction<? super K> transformer;
5708	>	final DoubleBinaryOperator reducer;
5709	>	final double basis;
5710	>	double result;
5711	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5712	>	MapReduceKeysToDoubleTask
5713	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5714	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5715	>	ToDoubleFunction<? super K> transformer,
5716	>	double basis,
5717	>	DoubleBinaryOperator reducer) {
5718	>	super(p, b, i, f, t); this.nextRight = nextRight;
5719	>	this.transformer = transformer;
5720	>	this.basis = basis; this.reducer = reducer;
5721	>	}
5722	>	public final Double getRawResult() { return result; }
5723	>	public final void compute() {
5724	>	final ToDoubleFunction<? super K> transformer;
5725	>	final DoubleBinaryOperator reducer;
5726	>	if ((transformer = this.transformer) != null &&
5727	>	(reducer = this.reducer) != null) {
5728	>	double r = this.basis;
5729	>	for (int i = baseIndex, f, h; batch > 0 &&
5730	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5731	>	addToPendingCount(1);
5732	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5733	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5734	>	rights, transformer, r, reducer)).fork();
5735	>	}
5736	>	for (Node<K,V> p; (p = advance()) != null; )
5737	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5738	>	result = r;
5739	>	CountedCompleter<?> c;
5740	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5741	>	@SuppressWarnings("unchecked")
5742	>	MapReduceKeysToDoubleTask<K,V>
5743	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5744	>	s = t.rights;
5745	>	while (s != null) {
5746	>	t.result = reducer.applyAsDouble(t.result, s.result);
5747	>	s = t.rights = s.nextRight;
5748	>	}
5749	>	}
5750	>	}
5751	>	}
5752	>	}
5753	>
5754	>	@SuppressWarnings("serial")
5755	>	static final class MapReduceValuesToDoubleTask<K,V>
5756	>	extends BulkTask<K,V,Double> {
5757	>	final ToDoubleFunction<? super V> transformer;
5758	>	final DoubleBinaryOperator reducer;
5759	>	final double basis;
5760	>	double result;
5761	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5762	>	MapReduceValuesToDoubleTask
5763	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5764	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5765	>	ToDoubleFunction<? super V> transformer,
5766	>	double basis,
5767	>	DoubleBinaryOperator reducer) {
5768	>	super(p, b, i, f, t); this.nextRight = nextRight;
5769	>	this.transformer = transformer;
5770	>	this.basis = basis; this.reducer = reducer;
5771	>	}
5772	>	public final Double getRawResult() { return result; }
5773	>	public final void compute() {
5774	>	final ToDoubleFunction<? super V> transformer;
5775	>	final DoubleBinaryOperator reducer;
5776	>	if ((transformer = this.transformer) != null &&
5777	>	(reducer = this.reducer) != null) {
5778	>	double r = this.basis;
5779	>	for (int i = baseIndex, f, h; batch > 0 &&
5780	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5781	>	addToPendingCount(1);
5782	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5783	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5784	>	rights, transformer, r, reducer)).fork();
5785	>	}
5786	>	for (Node<K,V> p; (p = advance()) != null; )
5787	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5788	>	result = r;
5789	>	CountedCompleter<?> c;
5790	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5791	>	@SuppressWarnings("unchecked")
5792	>	MapReduceValuesToDoubleTask<K,V>
5793	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5794	>	s = t.rights;
5795	>	while (s != null) {
5796	>	t.result = reducer.applyAsDouble(t.result, s.result);
5797	>	s = t.rights = s.nextRight;
5798	>	}
5799	>	}
5800	>	}
5801	>	}
5802	>	}
5803	>
5804	>	@SuppressWarnings("serial")
5805	>	static final class MapReduceEntriesToDoubleTask<K,V>
5806	>	extends BulkTask<K,V,Double> {
5807	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5808	>	final DoubleBinaryOperator reducer;
5809	>	final double basis;
5810	>	double result;
5811	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5812	>	MapReduceEntriesToDoubleTask
5813	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5814	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5815	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5816	>	double basis,
5817	>	DoubleBinaryOperator reducer) {
5818	>	super(p, b, i, f, t); this.nextRight = nextRight;
5819	>	this.transformer = transformer;
5820	>	this.basis = basis; this.reducer = reducer;
5821	>	}
5822	>	public final Double getRawResult() { return result; }
5823	>	public final void compute() {
5824	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5825	>	final DoubleBinaryOperator reducer;
5826	>	if ((transformer = this.transformer) != null &&
5827	>	(reducer = this.reducer) != null) {
5828	>	double r = this.basis;
5829	>	for (int i = baseIndex, f, h; batch > 0 &&
5830	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5831	>	addToPendingCount(1);
5832	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5833	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5834	>	rights, transformer, r, reducer)).fork();
5835	>	}
5836	>	for (Node<K,V> p; (p = advance()) != null; )
5837	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5838	>	result = r;
5839	>	CountedCompleter<?> c;
5840	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5841	>	@SuppressWarnings("unchecked")
5842	>	MapReduceEntriesToDoubleTask<K,V>
5843	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5844	>	s = t.rights;
5845	>	while (s != null) {
5846	>	t.result = reducer.applyAsDouble(t.result, s.result);
5847	>	s = t.rights = s.nextRight;
5848	>	}
5849	>	}
5850	>	}
5851	>	}
5852	>	}
5853	>
5854	>	@SuppressWarnings("serial")
5855	>	static final class MapReduceMappingsToDoubleTask<K,V>
5856	>	extends BulkTask<K,V,Double> {
5857	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5858	>	final DoubleBinaryOperator reducer;
5859	>	final double basis;
5860	>	double result;
5861	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5862	>	MapReduceMappingsToDoubleTask
5863	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5864	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5865	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5866	>	double basis,
5867	>	DoubleBinaryOperator reducer) {
5868	>	super(p, b, i, f, t); this.nextRight = nextRight;
5869	>	this.transformer = transformer;
5870	>	this.basis = basis; this.reducer = reducer;
5871	>	}
5872	>	public final Double getRawResult() { return result; }
5873	>	public final void compute() {
5874	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5875	>	final DoubleBinaryOperator reducer;
5876	>	if ((transformer = this.transformer) != null &&
5877	>	(reducer = this.reducer) != null) {
5878	>	double r = this.basis;
5879	>	for (int i = baseIndex, f, h; batch > 0 &&
5880	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5881	>	addToPendingCount(1);
5882	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5883	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5884	>	rights, transformer, r, reducer)).fork();
5885	>	}
5886	>	for (Node<K,V> p; (p = advance()) != null; )
5887	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5888	>	result = r;
5889	>	CountedCompleter<?> c;
5890	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5891	>	@SuppressWarnings("unchecked")
5892	>	MapReduceMappingsToDoubleTask<K,V>
5893	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5894	>	s = t.rights;
5895	>	while (s != null) {
5896	>	t.result = reducer.applyAsDouble(t.result, s.result);
5897	>	s = t.rights = s.nextRight;
5898	>	}
5899	>	}
5900	>	}
5901	>	}
5902	>	}
5903	>
5904	>	@SuppressWarnings("serial")
5905	>	static final class MapReduceKeysToLongTask<K,V>
5906	>	extends BulkTask<K,V,Long> {
5907	>	final ToLongFunction<? super K> transformer;
5908	>	final LongBinaryOperator reducer;
5909	>	final long basis;
5910	>	long result;
5911	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5912	>	MapReduceKeysToLongTask
5913	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5914	>	MapReduceKeysToLongTask<K,V> nextRight,
5915	>	ToLongFunction<? super K> transformer,
5916	>	long basis,
5917	>	LongBinaryOperator reducer) {
5918	>	super(p, b, i, f, t); this.nextRight = nextRight;
5919	>	this.transformer = transformer;
5920	>	this.basis = basis; this.reducer = reducer;
5921	>	}
5922	>	public final Long getRawResult() { return result; }
5923	>	public final void compute() {
5924	>	final ToLongFunction<? super K> transformer;
5925	>	final LongBinaryOperator reducer;
5926	>	if ((transformer = this.transformer) != null &&
5927	>	(reducer = this.reducer) != null) {
5928	>	long r = this.basis;
5929	>	for (int i = baseIndex, f, h; batch > 0 &&
5930	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5931	>	addToPendingCount(1);
5932	>	(rights = new MapReduceKeysToLongTask<K,V>
5933	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5934	>	rights, transformer, r, reducer)).fork();
5935	>	}
5936	>	for (Node<K,V> p; (p = advance()) != null; )
5937	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5938	>	result = r;
5939	>	CountedCompleter<?> c;
5940	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5941	>	@SuppressWarnings("unchecked")
5942	>	MapReduceKeysToLongTask<K,V>
5943	>	t = (MapReduceKeysToLongTask<K,V>)c,
5944	>	s = t.rights;
5945	>	while (s != null) {
5946	>	t.result = reducer.applyAsLong(t.result, s.result);
5947	>	s = t.rights = s.nextRight;
5948	>	}
5949	>	}
5950	>	}
5951	>	}
5952	>	}
5953	>
5954	>	@SuppressWarnings("serial")
5955	>	static final class MapReduceValuesToLongTask<K,V>
5956	>	extends BulkTask<K,V,Long> {
5957	>	final ToLongFunction<? super V> transformer;
5958	>	final LongBinaryOperator reducer;
5959	>	final long basis;
5960	>	long result;
5961	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5962	>	MapReduceValuesToLongTask
5963	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5964	>	MapReduceValuesToLongTask<K,V> nextRight,
5965	>	ToLongFunction<? super V> transformer,
5966	>	long basis,
5967	>	LongBinaryOperator reducer) {
5968	>	super(p, b, i, f, t); this.nextRight = nextRight;
5969	>	this.transformer = transformer;
5970	>	this.basis = basis; this.reducer = reducer;
5971	>	}
5972	>	public final Long getRawResult() { return result; }
5973	>	public final void compute() {
5974	>	final ToLongFunction<? super V> transformer;
5975	>	final LongBinaryOperator reducer;
5976	>	if ((transformer = this.transformer) != null &&
5977	>	(reducer = this.reducer) != null) {
5978	>	long r = this.basis;
5979	>	for (int i = baseIndex, f, h; batch > 0 &&
5980	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5981	>	addToPendingCount(1);
5982	>	(rights = new MapReduceValuesToLongTask<K,V>
5983	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5984	>	rights, transformer, r, reducer)).fork();
5985	>	}
5986	>	for (Node<K,V> p; (p = advance()) != null; )
5987	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5988	>	result = r;
5989	>	CountedCompleter<?> c;
5990	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5991	>	@SuppressWarnings("unchecked")
5992	>	MapReduceValuesToLongTask<K,V>
5993	>	t = (MapReduceValuesToLongTask<K,V>)c,
5994	>	s = t.rights;
5995	>	while (s != null) {
5996	>	t.result = reducer.applyAsLong(t.result, s.result);
5997	>	s = t.rights = s.nextRight;
5998	>	}
5999	>	}
6000	>	}
6001	>	}
6002	>	}
6003	>
6004	>	@SuppressWarnings("serial")
6005	>	static final class MapReduceEntriesToLongTask<K,V>
6006	>	extends BulkTask<K,V,Long> {
6007	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6008	>	final LongBinaryOperator reducer;
6009	>	final long basis;
6010	>	long result;
6011	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6012	>	MapReduceEntriesToLongTask
6013	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6014	>	MapReduceEntriesToLongTask<K,V> nextRight,
6015	>	ToLongFunction<Map.Entry<K,V>> transformer,
6016	>	long basis,
6017	>	LongBinaryOperator reducer) {
6018	>	super(p, b, i, f, t); this.nextRight = nextRight;
6019	>	this.transformer = transformer;
6020	>	this.basis = basis; this.reducer = reducer;
6021	>	}
6022	>	public final Long getRawResult() { return result; }
6023	>	public final void compute() {
6024	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6025	>	final LongBinaryOperator reducer;
6026	>	if ((transformer = this.transformer) != null &&
6027	>	(reducer = this.reducer) != null) {
6028	>	long r = this.basis;
6029	>	for (int i = baseIndex, f, h; batch > 0 &&
6030	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6031	>	addToPendingCount(1);
6032	>	(rights = new MapReduceEntriesToLongTask<K,V>
6033	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6034	>	rights, transformer, r, reducer)).fork();
6035	>	}
6036	>	for (Node<K,V> p; (p = advance()) != null; )
6037	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6038	>	result = r;
6039	>	CountedCompleter<?> c;
6040	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6041	>	@SuppressWarnings("unchecked")
6042	>	MapReduceEntriesToLongTask<K,V>
6043	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6044	>	s = t.rights;
6045	>	while (s != null) {
6046	>	t.result = reducer.applyAsLong(t.result, s.result);
6047	>	s = t.rights = s.nextRight;
6048	>	}
6049	>	}
6050	>	}
6051	>	}
6052	>	}
6053	>
6054	>	@SuppressWarnings("serial")
6055	>	static final class MapReduceMappingsToLongTask<K,V>
6056	>	extends BulkTask<K,V,Long> {
6057	>	final ToLongBiFunction<? super K, ? super V> transformer;
6058	>	final LongBinaryOperator reducer;
6059	>	final long basis;
6060	>	long result;
6061	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6062	>	MapReduceMappingsToLongTask
6063	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6064	>	MapReduceMappingsToLongTask<K,V> nextRight,
6065	>	ToLongBiFunction<? super K, ? super V> transformer,
6066	>	long basis,
6067	>	LongBinaryOperator reducer) {
6068	>	super(p, b, i, f, t); this.nextRight = nextRight;
6069	>	this.transformer = transformer;
6070	>	this.basis = basis; this.reducer = reducer;
6071	>	}
6072	>	public final Long getRawResult() { return result; }
6073	>	public final void compute() {
6074	>	final ToLongBiFunction<? super K, ? super V> transformer;
6075	>	final LongBinaryOperator reducer;
6076	>	if ((transformer = this.transformer) != null &&
6077	>	(reducer = this.reducer) != null) {
6078	>	long r = this.basis;
6079	>	for (int i = baseIndex, f, h; batch > 0 &&
6080	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6081	>	addToPendingCount(1);
6082	>	(rights = new MapReduceMappingsToLongTask<K,V>
6083	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6084	>	rights, transformer, r, reducer)).fork();
6085	>	}
6086	>	for (Node<K,V> p; (p = advance()) != null; )
6087	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6088	>	result = r;
6089	>	CountedCompleter<?> c;
6090	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6091	>	@SuppressWarnings("unchecked")
6092	>	MapReduceMappingsToLongTask<K,V>
6093	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6094	>	s = t.rights;
6095	>	while (s != null) {
6096	>	t.result = reducer.applyAsLong(t.result, s.result);
6097	>	s = t.rights = s.nextRight;
6098	>	}
6099	>	}
6100	>	}
6101	>	}
6102	>	}
6103	>
6104	>	@SuppressWarnings("serial")
6105	>	static final class MapReduceKeysToIntTask<K,V>
6106	>	extends BulkTask<K,V,Integer> {
6107	>	final ToIntFunction<? super K> transformer;
6108	>	final IntBinaryOperator reducer;
6109	>	final int basis;
6110	>	int result;
6111	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6112	>	MapReduceKeysToIntTask
6113	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6114	>	MapReduceKeysToIntTask<K,V> nextRight,
6115	>	ToIntFunction<? super K> transformer,
6116	>	int basis,
6117	>	IntBinaryOperator reducer) {
6118	>	super(p, b, i, f, t); this.nextRight = nextRight;
6119	>	this.transformer = transformer;
6120	>	this.basis = basis; this.reducer = reducer;
6121	>	}
6122	>	public final Integer getRawResult() { return result; }
6123	>	public final void compute() {
6124	>	final ToIntFunction<? super K> transformer;
6125	>	final IntBinaryOperator reducer;
6126	>	if ((transformer = this.transformer) != null &&
6127	>	(reducer = this.reducer) != null) {
6128	>	int r = this.basis;
6129	>	for (int i = baseIndex, f, h; batch > 0 &&
6130	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6131	>	addToPendingCount(1);
6132	>	(rights = new MapReduceKeysToIntTask<K,V>
6133	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6134	>	rights, transformer, r, reducer)).fork();
6135	>	}
6136	>	for (Node<K,V> p; (p = advance()) != null; )
6137	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6138	>	result = r;
6139	>	CountedCompleter<?> c;
6140	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6141	>	@SuppressWarnings("unchecked")
6142	>	MapReduceKeysToIntTask<K,V>
6143	>	t = (MapReduceKeysToIntTask<K,V>)c,
6144	>	s = t.rights;
6145	>	while (s != null) {
6146	>	t.result = reducer.applyAsInt(t.result, s.result);
6147	>	s = t.rights = s.nextRight;
6148	>	}
6149	>	}
6150	>	}
6151		}
6152		}
6153	+
6154	+	@SuppressWarnings("serial")
6155	+	static final class MapReduceValuesToIntTask<K,V>
6156	+	extends BulkTask<K,V,Integer> {
6157	+	final ToIntFunction<? super V> transformer;
6158	+	final IntBinaryOperator reducer;
6159	+	final int basis;
6160	+	int result;
6161	+	MapReduceValuesToIntTask<K,V> rights, nextRight;
6162	+	MapReduceValuesToIntTask
6163	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6164	+	MapReduceValuesToIntTask<K,V> nextRight,
6165	+	ToIntFunction<? super V> transformer,
6166	+	int basis,
6167	+	IntBinaryOperator reducer) {
6168	+	super(p, b, i, f, t); this.nextRight = nextRight;
6169	+	this.transformer = transformer;
6170	+	this.basis = basis; this.reducer = reducer;
6171	+	}
6172	+	public final Integer getRawResult() { return result; }
6173	+	public final void compute() {
6174	+	final ToIntFunction<? super V> transformer;
6175	+	final IntBinaryOperator reducer;
6176	+	if ((transformer = this.transformer) != null &&
6177	+	(reducer = this.reducer) != null) {
6178	+	int r = this.basis;
6179	+	for (int i = baseIndex, f, h; batch > 0 &&
6180	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6181	+	addToPendingCount(1);
6182	+	(rights = new MapReduceValuesToIntTask<K,V>
6183	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6184	+	rights, transformer, r, reducer)).fork();
6185	+	}
6186	+	for (Node<K,V> p; (p = advance()) != null; )
6187	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6188	+	result = r;
6189	+	CountedCompleter<?> c;
6190	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6191	+	@SuppressWarnings("unchecked")
6192	+	MapReduceValuesToIntTask<K,V>
6193	+	t = (MapReduceValuesToIntTask<K,V>)c,
6194	+	s = t.rights;
6195	+	while (s != null) {
6196	+	t.result = reducer.applyAsInt(t.result, s.result);
6197	+	s = t.rights = s.nextRight;
6198	+	}
6199	+	}
6200	+	}
6201	+	}
6202	+	}
6203	+
6204	+	@SuppressWarnings("serial")
6205	+	static final class MapReduceEntriesToIntTask<K,V>
6206	+	extends BulkTask<K,V,Integer> {
6207	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6208	+	final IntBinaryOperator reducer;
6209	+	final int basis;
6210	+	int result;
6211	+	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6212	+	MapReduceEntriesToIntTask
6213	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6214	+	MapReduceEntriesToIntTask<K,V> nextRight,
6215	+	ToIntFunction<Map.Entry<K,V>> transformer,
6216	+	int basis,
6217	+	IntBinaryOperator reducer) {
6218	+	super(p, b, i, f, t); this.nextRight = nextRight;
6219	+	this.transformer = transformer;
6220	+	this.basis = basis; this.reducer = reducer;
6221	+	}
6222	+	public final Integer getRawResult() { return result; }
6223	+	public final void compute() {
6224	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6225	+	final IntBinaryOperator reducer;
6226	+	if ((transformer = this.transformer) != null &&
6227	+	(reducer = this.reducer) != null) {
6228	+	int r = this.basis;
6229	+	for (int i = baseIndex, f, h; batch > 0 &&
6230	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6231	+	addToPendingCount(1);
6232	+	(rights = new MapReduceEntriesToIntTask<K,V>
6233	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6234	+	rights, transformer, r, reducer)).fork();
6235	+	}
6236	+	for (Node<K,V> p; (p = advance()) != null; )
6237	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6238	+	result = r;
6239	+	CountedCompleter<?> c;
6240	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6241	+	@SuppressWarnings("unchecked")
6242	+	MapReduceEntriesToIntTask<K,V>
6243	+	t = (MapReduceEntriesToIntTask<K,V>)c,
6244	+	s = t.rights;
6245	+	while (s != null) {
6246	+	t.result = reducer.applyAsInt(t.result, s.result);
6247	+	s = t.rights = s.nextRight;
6248	+	}
6249	+	}
6250	+	}
6251	+	}
6252	+	}
6253	+
6254	+	@SuppressWarnings("serial")
6255	+	static final class MapReduceMappingsToIntTask<K,V>
6256	+	extends BulkTask<K,V,Integer> {
6257	+	final ToIntBiFunction<? super K, ? super V> transformer;
6258	+	final IntBinaryOperator reducer;
6259	+	final int basis;
6260	+	int result;
6261	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6262	+	MapReduceMappingsToIntTask
6263	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6264	+	MapReduceMappingsToIntTask<K,V> nextRight,
6265	+	ToIntBiFunction<? super K, ? super V> transformer,
6266	+	int basis,
6267	+	IntBinaryOperator reducer) {
6268	+	super(p, b, i, f, t); this.nextRight = nextRight;
6269	+	this.transformer = transformer;
6270	+	this.basis = basis; this.reducer = reducer;
6271	+	}
6272	+	public final Integer getRawResult() { return result; }
6273	+	public final void compute() {
6274	+	final ToIntBiFunction<? super K, ? super V> transformer;
6275	+	final IntBinaryOperator reducer;
6276	+	if ((transformer = this.transformer) != null &&
6277	+	(reducer = this.reducer) != null) {
6278	+	int r = this.basis;
6279	+	for (int i = baseIndex, f, h; batch > 0 &&
6280	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6281	+	addToPendingCount(1);
6282	+	(rights = new MapReduceMappingsToIntTask<K,V>
6283	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6284	+	rights, transformer, r, reducer)).fork();
6285	+	}
6286	+	for (Node<K,V> p; (p = advance()) != null; )
6287	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6288	+	result = r;
6289	+	CountedCompleter<?> c;
6290	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6291	+	@SuppressWarnings("unchecked")
6292	+	MapReduceMappingsToIntTask<K,V>
6293	+	t = (MapReduceMappingsToIntTask<K,V>)c,
6294	+	s = t.rights;
6295	+	while (s != null) {
6296	+	t.result = reducer.applyAsInt(t.result, s.result);
6297	+	s = t.rights = s.nextRight;
6298	+	}
6299	+	}
6300	+	}
6301	+	}
6302	+	}
6303	+
6304	+	// Unsafe mechanics
6305	+	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
6306	+	private static final long SIZECTL;
6307	+	private static final long TRANSFERINDEX;
6308	+	private static final long BASECOUNT;
6309	+	private static final long CELLSBUSY;
6310	+	private static final long CELLVALUE;
6311	+	private static final int ABASE;
6312	+	private static final int ASHIFT;
6313	+
6314	+	static {
6315	+	try {
6316	+	SIZECTL = U.objectFieldOffset
6317	+	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6318	+	TRANSFERINDEX = U.objectFieldOffset
6319	+	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6320	+	BASECOUNT = U.objectFieldOffset
6321	+	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6322	+	CELLSBUSY = U.objectFieldOffset
6323	+	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6324	+
6325	+	CELLVALUE = U.objectFieldOffset
6326	+	(CounterCell.class.getDeclaredField("value"));
6327	+
6328	+	ABASE = U.arrayBaseOffset(Node[].class);
6329	+	int scale = U.arrayIndexScale(Node[].class);
6330	+	if ((scale & (scale - 1)) != 0)
6331	+	throw new Error("array index scale not a power of two");
6332	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6333	+	} catch (ReflectiveOperationException e) {
6334	+	throw new Error(e);
6335	+	}
6336	+
6337	+	// Reduce the risk of rare disastrous classloading in first call to
6338	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6339	+	Class<?> ensureLoaded = LockSupport.class;
6340	+	}
6341		}
1048	–

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines