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Revision 1.24 by dl, Fri Oct 10 23:51:28 2003 UTC vs.
Revision 1.266 by dl, Mon Feb 23 19:51:36 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	<	import java.util.concurrent.locks.*;
9	<	import java.util.*;
8	>
9	>	import java.io.ObjectStreamField;
10		import java.io.Serializable;
11	<	import java.io.IOException;
12	<	import java.io.ObjectInputStream;
13	<	import java.io.ObjectOutputStream;
11	>	import java.lang.reflect.ParameterizedType;
12	>	import java.lang.reflect.Type;
13	>	import java.util.AbstractMap;
14	>	import java.util.Arrays;
15	>	import java.util.Collection;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.atomic.AtomicReference;
25	>	import java.util.concurrent.locks.LockSupport;
26	>	import java.util.concurrent.locks.ReentrantLock;
27	>	import java.util.function.BiConsumer;
28	>	import java.util.function.BiFunction;
29	>	import java.util.function.Consumer;
30	>	import java.util.function.DoubleBinaryOperator;
31	>	import java.util.function.Function;
32	>	import java.util.function.IntBinaryOperator;
33	>	import java.util.function.LongBinaryOperator;
34	>	import java.util.function.ToDoubleBiFunction;
35	>	import java.util.function.ToDoubleFunction;
36	>	import java.util.function.ToIntBiFunction;
37	>	import java.util.function.ToIntFunction;
38	>	import java.util.function.ToLongBiFunction;
39	>	import java.util.function.ToLongFunction;
40	>	import java.util.stream.Stream;
41
42		/**
43		* A hash table supporting full concurrency of retrievals and
44	<	* adjustable expected concurrency for updates. This class obeys the
44	>	* high expected concurrency for updates. This class obeys the
45		* same functional specification as {@link java.util.Hashtable}, and
46		* includes versions of methods corresponding to each method of
47	<	* <tt>Hashtable</tt> . However, even though all operations are
47	>	* {@code Hashtable}. However, even though all operations are
48		* thread-safe, retrieval operations do <em>not</em> entail locking,
49		* and there is <em>not</em> any support for locking the entire table
50		* in a way that prevents all access.  This class is fully
51	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
51	>	* interoperable with {@code Hashtable} in programs that rely on its
52		* thread safety but not on its synchronization details.
53		*
54	<	* <p> Retrieval operations (including <tt>get</tt>) ordinarily
55	<	* overlap with update operations (including <tt>put</tt> and
56	<	* <tt>remove</tt>). Retrievals reflect the results of the most
54	>	* <p>Retrieval operations (including {@code get}) generally do not
55	>	* block, so may overlap with update operations (including {@code put}
56	>	* and {@code remove}). Retrievals reflect the results of the most
57		* recently <em>completed</em> update operations holding upon their
58	<	* onset.  For aggregate operations such as <tt>putAll</tt> and
59	<	* <tt>clear</tt>, concurrent retrievals may reflect insertion or
60	<	* removal of only some entries.  Similarly, Iterators and
61	<	* Enumerations return elements reflecting the state of the hash table
62	<	* at some point at or since the creation of the iterator/enumeration.
63	<	* They do <em>not</em> throw <tt>ConcurrentModificationException</tt>.
64	<	* However, Iterators are designed to be used by only one thread at a
65	<	* time.
66	<	*
67	<	* <p> The allowed concurrency among update operations is guided by
68	<	* the optional <tt>concurrencyLevel</tt> constructor argument
69	<	* (default 16), which is used as a hint for internal sizing.  The
70	<	* table is internally partitioned to try to permit the indicated
71	<	* number of concurrent updates without contention. Because placement
72	<	* in hash tables is essentially random, the actual concurrency will
73	<	* vary.  Ideally, you should choose a value to accommodate as many
74	<	* threads as will ever concurrently access the table. Using a
75	<	* significantly higher value than you need can waste space and time,
76	<	* and a significantly lower value can lead to thread contention. But
77	<	* overestimates and underestimates within an order of magnitude do
78	<	* not usually have much noticeable impact.
79	<	*
80	<	* <p>This class implements all of the <em>optional</em> methods
81	<	* of the {@link Map} and {@link Iterator} interfaces.
82	<	*
83	<	* <p> Like {@link java.util.Hashtable} but unlike {@link
84	<	* java.util.HashMap}, this class does NOT allow <tt>null</tt> to be
85	<	* used as a key or value.
58	>	* onset. (More formally, an update operation for a given key bears a
59	>	* <em>happens-before</em> relation with any (non-null) retrieval for
60	>	* that key reporting the updated value.)  For aggregate operations
61	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
62	>	* reflect insertion or removal of only some entries.  Similarly,
63	>	* Iterators, Spliterators and Enumerations return elements reflecting the
64	>	* state of the hash table at some point at or since the creation of the
65	>	* iterator/enumeration.  They do <em>not</em> throw {@link
66	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
67	>	* However, iterators are designed to be used by only one thread at a time.
68	>	* Bear in mind that the results of aggregate status methods including
69	>	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
70	>	* useful only when a map is not undergoing concurrent updates in other threads.
71	>	* Otherwise the results of these methods reflect transient states
72	>	* that may be adequate for monitoring or estimation purposes, but not
73	>	* for program control.
74	>	*
75	>	* <p>The table is dynamically expanded when there are too many
76	>	* collisions (i.e., keys that have distinct hash codes but fall into
77	>	* the same slot modulo the table size), with the expected average
78	>	* effect of maintaining roughly two bins per mapping (corresponding
79	>	* to a 0.75 load factor threshold for resizing). There may be much
80	>	* variance around this average as mappings are added and removed, but
81	>	* overall, this maintains a commonly accepted time/space tradeoff for
82	>	* hash tables.  However, resizing this or any other kind of hash
83	>	* table may be a relatively slow operation. When possible, it is a
84	>	* good idea to provide a size estimate as an optional {@code
85	>	* initialCapacity} constructor argument. An additional optional
86	>	* {@code loadFactor} constructor argument provides a further means of
87	>	* customizing initial table capacity by specifying the table density
88	>	* to be used in calculating the amount of space to allocate for the
89	>	* given number of elements.  Also, for compatibility with previous
90	>	* versions of this class, constructors may optionally specify an
91	>	* expected {@code concurrencyLevel} as an additional hint for
92	>	* internal sizing.  Note that using many keys with exactly the same
93	>	* {@code hashCode()} is a sure way to slow down performance of any
94	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
95	>	* this class may use comparison order among keys to help break ties.
96	>	*
97	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
98	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
99	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
100	>	* mapped values are (perhaps transiently) not used or all take the
101	>	* same mapping value.
102	>	*
103	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
104	>	* form of histogram or multiset) by using {@link
105	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
106	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
107	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
108	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
109	>	*
110	>	* <p>This class and its views and iterators implement all of the
111	>	* <em>optional</em> methods of the {@link Map} and {@link Iterator}
112	>	* interfaces.
113	>	*
114	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
115	>	* does <em>not</em> allow {@code null} to be used as a key or value.
116	>	*
117	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
118	>	* operations that, unlike most {@link Stream} methods, are designed
119	>	* to be safely, and often sensibly, applied even with maps that are
120	>	* being concurrently updated by other threads; for example, when
121	>	* computing a snapshot summary of the values in a shared registry.
122	>	* There are three kinds of operation, each with four forms, accepting
123	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
124	>	* and/or return values. Because the elements of a ConcurrentHashMap
125	>	* are not ordered in any particular way, and may be processed in
126	>	* different orders in different parallel executions, the correctness
127	>	* of supplied functions should not depend on any ordering, or on any
128	>	* other objects or values that may transiently change while
129	>	* computation is in progress; and except for forEach actions, should
130	>	* ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry}
131	>	* objects do not support method {@code setValue}.
132	>	*
133	>	* <ul>
134	>	* <li> forEach: Perform a given action on each element.
135	>	* A variant form applies a given transformation on each element
136	>	* before performing the action.</li>
137	>	*
138	>	* <li> search: Return the first available non-null result of
139	>	* applying a given function on each element; skipping further
140	>	* search when a result is found.</li>
141	>	*
142	>	* <li> reduce: Accumulate each element.  The supplied reduction
143	>	* function cannot rely on ordering (more formally, it should be
144	>	* both associative and commutative).  There are five variants:
145	>	*
146	>	* <ul>
147	>	*
148	>	* <li> Plain reductions. (There is not a form of this method for
149	>	* (key, value) function arguments since there is no corresponding
150	>	* return type.)</li>
151	>	*
152	>	* <li> Mapped reductions that accumulate the results of a given
153	>	* function applied to each element.</li>
154	>	*
155	>	* <li> Reductions to scalar doubles, longs, and ints, using a
156	>	* given basis value.</li>
157	>	*
158	>	* </ul>
159	>	* </li>
160	>	* </ul>
161	>	*
162	>	* <p>These bulk operations accept a {@code parallelismThreshold}
163	>	* argument. Methods proceed sequentially if the current map size is
164	>	* estimated to be less than the given threshold. Using a value of
165	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
166	>	* of {@code 1} results in maximal parallelism by partitioning into
167	>	* enough subtasks to fully utilize the {@link
168	>	* ForkJoinPool#commonPool()} that is used for all parallel
169	>	* computations. Normally, you would initially choose one of these
170	>	* extreme values, and then measure performance of using in-between
171	>	* values that trade off overhead versus throughput.
172	>	*
173	>	* <p>The concurrency properties of bulk operations follow
174	>	* from those of ConcurrentHashMap: Any non-null result returned
175	>	* from {@code get(key)} and related access methods bears a
176	>	* happens-before relation with the associated insertion or
177	>	* update.  The result of any bulk operation reflects the
178	>	* composition of these per-element relations (but is not
179	>	* necessarily atomic with respect to the map as a whole unless it
180	>	* is somehow known to be quiescent).  Conversely, because keys
181	>	* and values in the map are never null, null serves as a reliable
182	>	* atomic indicator of the current lack of any result.  To
183	>	* maintain this property, null serves as an implicit basis for
184	>	* all non-scalar reduction operations. For the double, long, and
185	>	* int versions, the basis should be one that, when combined with
186	>	* any other value, returns that other value (more formally, it
187	>	* should be the identity element for the reduction). Most common
188	>	* reductions have these properties; for example, computing a sum
189	>	* with basis 0 or a minimum with basis MAX_VALUE.
190	>	*
191	>	* <p>Search and transformation functions provided as arguments
192	>	* should similarly return null to indicate the lack of any result
193	>	* (in which case it is not used). In the case of mapped
194	>	* reductions, this also enables transformations to serve as
195	>	* filters, returning null (or, in the case of primitive
196	>	* specializations, the identity basis) if the element should not
197	>	* be combined. You can create compound transformations and
198	>	* filterings by composing them yourself under this "null means
199	>	* there is nothing there now" rule before using them in search or
200	>	* reduce operations.
201	>	*
202	>	* <p>Methods accepting and/or returning Entry arguments maintain
203	>	* key-value associations. They may be useful for example when
204	>	* finding the key for the greatest value. Note that "plain" Entry
205	>	* arguments can be supplied using {@code new
206	>	* AbstractMap.SimpleEntry(k,v)}.
207	>	*
208	>	* <p>Bulk operations may complete abruptly, throwing an
209	>	* exception encountered in the application of a supplied
210	>	* function. Bear in mind when handling such exceptions that other
211	>	* concurrently executing functions could also have thrown
212	>	* exceptions, or would have done so if the first exception had
213	>	* not occurred.
214	>	*
215	>	* <p>Speedups for parallel compared to sequential forms are common
216	>	* but not guaranteed.  Parallel operations involving brief functions
217	>	* on small maps may execute more slowly than sequential forms if the
218	>	* underlying work to parallelize the computation is more expensive
219	>	* than the computation itself.  Similarly, parallelization may not
220	>	* lead to much actual parallelism if all processors are busy
221	>	* performing unrelated tasks.
222	>	*
223	>	* <p>All arguments to all task methods must be non-null.
224	>	*
225	>	* <p>This class is a member of the
226	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
227	>	* Java Collections Framework</a>.
228		*
229		* @since 1.5
230		* @author Doug Lea
231	+	* @param <K> the type of keys maintained by this map
232	+	* @param <V> the type of mapped values
233		*/
234	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
235	<	implements ConcurrentMap<K, V>, Cloneable, Serializable {
234	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
235	>	implements ConcurrentMap<K,V>, Serializable {
236		private static final long serialVersionUID = 7249069246763182397L;
237
238		/*
239	<	* The basic strategy is to subdivide the table among Segments,
240	<	* each of which itself is a concurrently readable hash table.
239	>	* Overview:
240	>	*
241	>	* The primary design goal of this hash table is to maintain
242	>	* concurrent readability (typically method get(), but also
243	>	* iterators and related methods) while minimizing update
244	>	* contention. Secondary goals are to keep space consumption about
245	>	* the same or better than java.util.HashMap, and to support high
246	>	* initial insertion rates on an empty table by many threads.
247	>	*
248	>	* This map usually acts as a binned (bucketed) hash table.  Each
249	>	* key-value mapping is held in a Node.  Most nodes are instances
250	>	* of the basic Node class with hash, key, value, and next
251	>	* fields. However, various subclasses exist: TreeNodes are
252	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
253	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
254	>	* of bins during resizing. ReservationNodes are used as
255	>	* placeholders while establishing values in computeIfAbsent and
256	>	* related methods.  The types TreeBin, ForwardingNode, and
257	>	* ReservationNode do not hold normal user keys, values, or
258	>	* hashes, and are readily distinguishable during search etc
259	>	* because they have negative hash fields and null key and value
260	>	* fields. (These special nodes are either uncommon or transient,
261	>	* so the impact of carrying around some unused fields is
262	>	* insignificant.)
263	>	*
264	>	* The table is lazily initialized to a power-of-two size upon the
265	>	* first insertion.  Each bin in the table normally contains a
266	>	* list of Nodes (most often, the list has only zero or one Node).
267	>	* Table accesses require volatile/atomic reads, writes, and
268	>	* CASes.  Because there is no other way to arrange this without
269	>	* adding further indirections, we use intrinsics
270	>	* (sun.misc.Unsafe) operations.
271	>	*
272	>	* We use the top (sign) bit of Node hash fields for control
273	>	* purposes -- it is available anyway because of addressing
274	>	* constraints.  Nodes with negative hash fields are specially
275	>	* handled or ignored in map methods.
276	>	*
277	>	* Insertion (via put or its variants) of the first node in an
278	>	* empty bin is performed by just CASing it to the bin.  This is
279	>	* by far the most common case for put operations under most
280	>	* key/hash distributions.  Other update operations (insert,
281	>	* delete, and replace) require locks.  We do not want to waste
282	>	* the space required to associate a distinct lock object with
283	>	* each bin, so instead use the first node of a bin list itself as
284	>	* a lock. Locking support for these locks relies on builtin
285	>	* "synchronized" monitors.
286	>	*
287	>	* Using the first node of a list as a lock does not by itself
288	>	* suffice though: When a node is locked, any update must first
289	>	* validate that it is still the first node after locking it, and
290	>	* retry if not. Because new nodes are always appended to lists,
291	>	* once a node is first in a bin, it remains first until deleted
292	>	* or the bin becomes invalidated (upon resizing).
293	>	*
294	>	* The main disadvantage of per-bin locks is that other update
295	>	* operations on other nodes in a bin list protected by the same
296	>	* lock can stall, for example when user equals() or mapping
297	>	* functions take a long time.  However, statistically, under
298	>	* random hash codes, this is not a common problem.  Ideally, the
299	>	* frequency of nodes in bins follows a Poisson distribution
300	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
301	>	* parameter of about 0.5 on average, given the resizing threshold
302	>	* of 0.75, although with a large variance because of resizing
303	>	* granularity. Ignoring variance, the expected occurrences of
304	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
305	>	* first values are:
306	>	*
307	>	* 0:    0.60653066
308	>	* 1:    0.30326533
309	>	* 2:    0.07581633
310	>	* 3:    0.01263606
311	>	* 4:    0.00157952
312	>	* 5:    0.00015795
313	>	* 6:    0.00001316
314	>	* 7:    0.00000094
315	>	* 8:    0.00000006
316	>	* more: less than 1 in ten million
317	>	*
318	>	* Lock contention probability for two threads accessing distinct
319	>	* elements is roughly 1 / (8 * #elements) under random hashes.
320	>	*
321	>	* Actual hash code distributions encountered in practice
322	>	* sometimes deviate significantly from uniform randomness.  This
323	>	* includes the case when N > (1<<30), so some keys MUST collide.
324	>	* Similarly for dumb or hostile usages in which multiple keys are
325	>	* designed to have identical hash codes or ones that differs only
326	>	* in masked-out high bits. So we use a secondary strategy that
327	>	* applies when the number of nodes in a bin exceeds a
328	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
329	>	* specialized form of red-black trees), bounding search time to
330	>	* O(log N).  Each search step in a TreeBin is at least twice as
331	>	* slow as in a regular list, but given that N cannot exceed
332	>	* (1<<64) (before running out of addresses) this bounds search
333	>	* steps, lock hold times, etc, to reasonable constants (roughly
334	>	* 100 nodes inspected per operation worst case) so long as keys
335	>	* are Comparable (which is very common -- String, Long, etc).
336	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
337	>	* traversal pointers as regular nodes, so can be traversed in
338	>	* iterators in the same way.
339	>	*
340	>	* The table is resized when occupancy exceeds a percentage
341	>	* threshold (nominally, 0.75, but see below).  Any thread
342	>	* noticing an overfull bin may assist in resizing after the
343	>	* initiating thread allocates and sets up the replacement array.
344	>	* However, rather than stalling, these other threads may proceed
345	>	* with insertions etc.  The use of TreeBins shields us from the
346	>	* worst case effects of overfilling while resizes are in
347	>	* progress.  Resizing proceeds by transferring bins, one by one,
348	>	* from the table to the next table. However, threads claim small
349	>	* blocks of indices to transfer (via field transferIndex) before
350	>	* doing so, reducing contention.  A generation stamp in field
351	>	* sizeCtl ensures that resizings do not overlap. Because we are
352	>	* using power-of-two expansion, the elements from each bin must
353	>	* either stay at same index, or move with a power of two
354	>	* offset. We eliminate unnecessary node creation by catching
355	>	* cases where old nodes can be reused because their next fields
356	>	* won't change.  On average, only about one-sixth of them need
357	>	* cloning when a table doubles. The nodes they replace will be
358	>	* garbage collectable as soon as they are no longer referenced by
359	>	* any reader thread that may be in the midst of concurrently
360	>	* traversing table.  Upon transfer, the old table bin contains
361	>	* only a special forwarding node (with hash field "MOVED") that
362	>	* contains the next table as its key. On encountering a
363	>	* forwarding node, access and update operations restart, using
364	>	* the new table.
365	>	*
366	>	* Each bin transfer requires its bin lock, which can stall
367	>	* waiting for locks while resizing. However, because other
368	>	* threads can join in and help resize rather than contend for
369	>	* locks, average aggregate waits become shorter as resizing
370	>	* progresses.  The transfer operation must also ensure that all
371	>	* accessible bins in both the old and new table are usable by any
372	>	* traversal.  This is arranged in part by proceeding from the
373	>	* last bin (table.length - 1) up towards the first.  Upon seeing
374	>	* a forwarding node, traversals (see class Traverser) arrange to
375	>	* move to the new table without revisiting nodes.  To ensure that
376	>	* no intervening nodes are skipped even when moved out of order,
377	>	* a stack (see class TableStack) is created on first encounter of
378	>	* a forwarding node during a traversal, to maintain its place if
379	>	* later processing the current table. The need for these
380	>	* save/restore mechanics is relatively rare, but when one
381	>	* forwarding node is encountered, typically many more will be.
382	>	* So Traversers use a simple caching scheme to avoid creating so
383	>	* many new TableStack nodes. (Thanks to Peter Levart for
384	>	* suggesting use of a stack here.)
385	>	*
386	>	* The traversal scheme also applies to partial traversals of
387	>	* ranges of bins (via an alternate Traverser constructor)
388	>	* to support partitioned aggregate operations.  Also, read-only
389	>	* operations give up if ever forwarded to a null table, which
390	>	* provides support for shutdown-style clearing, which is also not
391	>	* currently implemented.
392	>	*
393	>	* Lazy table initialization minimizes footprint until first use,
394	>	* and also avoids resizings when the first operation is from a
395	>	* putAll, constructor with map argument, or deserialization.
396	>	* These cases attempt to override the initial capacity settings,
397	>	* but harmlessly fail to take effect in cases of races.
398	>	*
399	>	* The element count is maintained using a specialization of
400	>	* LongAdder. We need to incorporate a specialization rather than
401	>	* just use a LongAdder in order to access implicit
402	>	* contention-sensing that leads to creation of multiple
403	>	* CounterCells.  The counter mechanics avoid contention on
404	>	* updates but can encounter cache thrashing if read too
405	>	* frequently during concurrent access. To avoid reading so often,
406	>	* resizing under contention is attempted only upon adding to a
407	>	* bin already holding two or more nodes. Under uniform hash
408	>	* distributions, the probability of this occurring at threshold
409	>	* is around 13%, meaning that only about 1 in 8 puts check
410	>	* threshold (and after resizing, many fewer do so).
411	>	*
412	>	* TreeBins use a special form of comparison for search and
413	>	* related operations (which is the main reason we cannot use
414	>	* existing collections such as TreeMaps). TreeBins contain
415	>	* Comparable elements, but may contain others, as well as
416	>	* elements that are Comparable but not necessarily Comparable for
417	>	* the same T, so we cannot invoke compareTo among them. To handle
418	>	* this, the tree is ordered primarily by hash value, then by
419	>	* Comparable.compareTo order if applicable.  On lookup at a node,
420	>	* if elements are not comparable or compare as 0 then both left
421	>	* and right children may need to be searched in the case of tied
422	>	* hash values. (This corresponds to the full list search that
423	>	* would be necessary if all elements were non-Comparable and had
424	>	* tied hashes.) On insertion, to keep a total ordering (or as
425	>	* close as is required here) across rebalancings, we compare
426	>	* classes and identityHashCodes as tie-breakers. The red-black
427	>	* balancing code is updated from pre-jdk-collections
428	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
429	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
430	>	* Algorithms" (CLR).
431	>	*
432	>	* TreeBins also require an additional locking mechanism.  While
433	>	* list traversal is always possible by readers even during
434	>	* updates, tree traversal is not, mainly because of tree-rotations
435	>	* that may change the root node and/or its linkages.  TreeBins
436	>	* include a simple read-write lock mechanism parasitic on the
437	>	* main bin-synchronization strategy: Structural adjustments
438	>	* associated with an insertion or removal are already bin-locked
439	>	* (and so cannot conflict with other writers) but must wait for
440	>	* ongoing readers to finish. Since there can be only one such
441	>	* waiter, we use a simple scheme using a single "waiter" field to
442	>	* block writers.  However, readers need never block.  If the root
443	>	* lock is held, they proceed along the slow traversal path (via
444	>	* next-pointers) until the lock becomes available or the list is
445	>	* exhausted, whichever comes first. These cases are not fast, but
446	>	* maximize aggregate expected throughput.
447	>	*
448	>	* Maintaining API and serialization compatibility with previous
449	>	* versions of this class introduces several oddities. Mainly: We
450	>	* leave untouched but unused constructor arguments refering to
451	>	* concurrencyLevel. We accept a loadFactor constructor argument,
452	>	* but apply it only to initial table capacity (which is the only
453	>	* time that we can guarantee to honor it.) We also declare an
454	>	* unused "Segment" class that is instantiated in minimal form
455	>	* only when serializing.
456	>	*
457	>	* Also, solely for compatibility with previous versions of this
458	>	* class, it extends AbstractMap, even though all of its methods
459	>	* are overridden, so it is just useless baggage.
460	>	*
461	>	* This file is organized to make things a little easier to follow
462	>	* while reading than they might otherwise: First the main static
463	>	* declarations and utilities, then fields, then main public
464	>	* methods (with a few factorings of multiple public methods into
465	>	* internal ones), then sizing methods, trees, traversers, and
466	>	* bulk operations.
467		*/
468
469		/* ---------------- Constants -------------- */
470
471		/**
472	<	* The default initial number of table slots for this table.
473	<	* Used when not otherwise specified in constructor.
472	>	* The largest possible table capacity.  This value must be
473	>	* exactly 1<<30 to stay within Java array allocation and indexing
474	>	* bounds for power of two table sizes, and is further required
475	>	* because the top two bits of 32bit hash fields are used for
476	>	* control purposes.
477		*/
478	<	private static int DEFAULT_INITIAL_CAPACITY = 16;
478	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
479	>
480	>	/**
481	>	* The default initial table capacity.  Must be a power of 2
482	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
483	>	*/
484	>	private static final int DEFAULT_CAPACITY = 16;
485	>
486	>	/**
487	>	* The largest possible (non-power of two) array size.
488	>	* Needed by toArray and related methods.
489	>	*/
490	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
491	>
492	>	/**
493	>	* The default concurrency level for this table. Unused but
494	>	* defined for compatibility with previous versions of this class.
495	>	*/
496	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
497	>
498	>	/**
499	>	* The load factor for this table. Overrides of this value in
500	>	* constructors affect only the initial table capacity.  The
501	>	* actual floating point value isn't normally used -- it is
502	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
503	>	* the associated resizing threshold.
504	>	*/
505	>	private static final float LOAD_FACTOR = 0.75f;
506	>
507	>	/**
508	>	* The bin count threshold for using a tree rather than list for a
509	>	* bin.  Bins are converted to trees when adding an element to a
510	>	* bin with at least this many nodes. The value must be greater
511	>	* than 2, and should be at least 8 to mesh with assumptions in
512	>	* tree removal about conversion back to plain bins upon
513	>	* shrinkage.
514	>	*/
515	>	static final int TREEIFY_THRESHOLD = 8;
516	>
517	>	/**
518	>	* The bin count threshold for untreeifying a (split) bin during a
519	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
520	>	* most 6 to mesh with shrinkage detection under removal.
521	>	*/
522	>	static final int UNTREEIFY_THRESHOLD = 6;
523	>
524	>	/**
525	>	* The smallest table capacity for which bins may be treeified.
526	>	* (Otherwise the table is resized if too many nodes in a bin.)
527	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
528	>	* conflicts between resizing and treeification thresholds.
529	>	*/
530	>	static final int MIN_TREEIFY_CAPACITY = 64;
531	>
532	>	/**
533	>	* Minimum number of rebinnings per transfer step. Ranges are
534	>	* subdivided to allow multiple resizer threads.  This value
535	>	* serves as a lower bound to avoid resizers encountering
536	>	* excessive memory contention.  The value should be at least
537	>	* DEFAULT_CAPACITY.
538	>	*/
539	>	private static final int MIN_TRANSFER_STRIDE = 16;
540	>
541	>	/**
542	>	* The number of bits used for generation stamp in sizeCtl.
543	>	* Must be at least 6 for 32bit arrays.
544	>	*/
545	>	private static int RESIZE_STAMP_BITS = 16;
546	>
547	>	/**
548	>	* The maximum number of threads that can help resize.
549	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
550	>	*/
551	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
552	>
553	>	/**
554	>	* The bit shift for recording size stamp in sizeCtl.
555	>	*/
556	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
557	>
558	>	/*
559	>	* Encodings for Node hash fields. See above for explanation.
560	>	*/
561	>	static final int MOVED     = -1; // hash for forwarding nodes
562	>	static final int TREEBIN   = -2; // hash for roots of trees
563	>	static final int RESERVED  = -3; // hash for transient reservations
564	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
565	>
566	>	/** Number of CPUS, to place bounds on some sizings */
567	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
568	>
569	>	/** For serialization compatibility. */
570	>	private static final ObjectStreamField[] serialPersistentFields = {
571	>	new ObjectStreamField("segments", Segment[].class),
572	>	new ObjectStreamField("segmentMask", Integer.TYPE),
573	>	new ObjectStreamField("segmentShift", Integer.TYPE)
574	>	};
575	>
576	>	/* ---------------- Nodes -------------- */
577	>
578	>	/**
579	>	* Key-value entry.  This class is never exported out as a
580	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
581	>	* MapEntry below), but can be used for read-only traversals used
582	>	* in bulk tasks.  Subclasses of Node with a negative hash field
583	>	* are special, and contain null keys and values (but are never
584	>	* exported).  Otherwise, keys and vals are never null.
585	>	*/
586	>	static class Node<K,V> implements Map.Entry<K,V> {
587	>	final int hash;
588	>	final K key;
589	>	volatile V val;
590	>	volatile Node<K,V> next;
591	>
592	>	Node(int hash, K key, V val, Node<K,V> next) {
593	>	this.hash = hash;
594	>	this.key = key;
595	>	this.val = val;
596	>	this.next = next;
597	>	}
598	>
599	>	public final K getKey()        { return key; }
600	>	public final V getValue()      { return val; }
601	>	public final String toString() { return key + "=" + val; }
602	>	public final int hashCode() {
603	>	return key.hashCode() ^ val.hashCode();
604	>	}
605	>	public final V setValue(V value) {
606	>	throw new UnsupportedOperationException();
607	>	}
608	>
609	>	public final boolean equals(Object o) {
610	>	Object k, v, u; Map.Entry<?,?> e;
611	>	return ((o instanceof Map.Entry) &&
612	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
613	>	(v = e.getValue()) != null &&
614	>	(k == key || k.equals(key)) &&
615	>	(v == (u = val) || v.equals(u)));
616	>	}
617	>
618	>	/**
619	>	* Virtualized support for map.get(); overridden in subclasses.
620	>	*/
621	>	Node<K,V> find(int h, Object k) {
622	>	Node<K,V> e = this;
623	>	if (k != null) {
624	>	do {
625	>	K ek;
626	>	if (e.hash == h &&
627	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
628	>	return e;
629	>	} while ((e = e.next) != null);
630	>	}
631	>	return null;
632	>	}
633	>	}
634	>
635	>	/* ---------------- Static utilities -------------- */
636
637		/**
638	<	* The maximum capacity, used if a higher value is implicitly
639	<	* specified by either of the constructors with arguments.  MUST
640	<	* be a power of two <= 1<<30 to ensure that entries are indexible
641	<	* using ints.
638	>	* Spreads (XORs) higher bits of hash to lower and also forces top
639	>	* bit to 0. Because the table uses power-of-two masking, sets of
640	>	* hashes that vary only in bits above the current mask will
641	>	* always collide. (Among known examples are sets of Float keys
642	>	* holding consecutive whole numbers in small tables.)  So we
643	>	* apply a transform that spreads the impact of higher bits
644	>	* downward. There is a tradeoff between speed, utility, and
645	>	* quality of bit-spreading. Because many common sets of hashes
646	>	* are already reasonably distributed (so don't benefit from
647	>	* spreading), and because we use trees to handle large sets of
648	>	* collisions in bins, we just XOR some shifted bits in the
649	>	* cheapest possible way to reduce systematic lossage, as well as
650	>	* to incorporate impact of the highest bits that would otherwise
651	>	* never be used in index calculations because of table bounds.
652		*/
653	<	static final int MAXIMUM_CAPACITY = 1 << 30;
653	>	static final int spread(int h) {
654	>	return (h ^ (h >>> 16)) & HASH_BITS;
655	>	}
656
657		/**
658	<	* The default load factor for this table.  Used when not
659	<	* otherwise specified in constructor.
658	>	* Returns a power of two table size for the given desired capacity.
659	>	* See Hackers Delight, sec 3.2
660		*/
661	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
661	>	private static final int tableSizeFor(int c) {
662	>	int n = c - 1;
663	>	n |= n >>> 1;
664	>	n |= n >>> 2;
665	>	n |= n >>> 4;
666	>	n |= n >>> 8;
667	>	n |= n >>> 16;
668	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
669	>	}
670
671		/**
672	<	* The default number of concurrency control segments.
673	<	**/
674	<	private static final int DEFAULT_SEGMENTS = 16;
672	>	* Returns x's Class if it is of the form "class C implements
673	>	* Comparable<C>", else null.
674	>	*/
675	>	static Class<?> comparableClassFor(Object x) {
676	>	if (x instanceof Comparable) {
677	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
678	>	if ((c = x.getClass()) == String.class) // bypass checks
679	>	return c;
680	>	if ((ts = c.getGenericInterfaces()) != null) {
681	>	for (int i = 0; i < ts.length; ++i) {
682	>	if (((t = ts[i]) instanceof ParameterizedType) &&
683	>	((p = (ParameterizedType)t).getRawType() ==
684	>	Comparable.class) &&
685	>	(as = p.getActualTypeArguments()) != null &&
686	>	as.length == 1 && as[0] == c) // type arg is c
687	>	return c;
688	>	}
689	>	}
690	>	}
691	>	return null;
692	>	}
693
694		/**
695	<	* The maximum number of segments to allow; used to bound ctor arguments.
695	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
696	>	* class), else 0.
697		*/
698	<	private static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
698	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
699	>	static int compareComparables(Class<?> kc, Object k, Object x) {
700	>	return (x == null || x.getClass() != kc ? 0 :
701	>	((Comparable)k).compareTo(x));
702	>	}
703	>
704	>	/* ---------------- Table element access -------------- */
705	>
706	>	/*
707	>	* Volatile access methods are used for table elements as well as
708	>	* elements of in-progress next table while resizing.  All uses of
709	>	* the tab arguments must be null checked by callers.  All callers
710	>	* also paranoically precheck that tab's length is not zero (or an
711	>	* equivalent check), thus ensuring that any index argument taking
712	>	* the form of a hash value anded with (length - 1) is a valid
713	>	* index.  Note that, to be correct wrt arbitrary concurrency
714	>	* errors by users, these checks must operate on local variables,
715	>	* which accounts for some odd-looking inline assignments below.
716	>	* Note that calls to setTabAt always occur within locked regions,
717	>	* and so in principle require only release ordering, not
718	>	* full volatile semantics, but are currently coded as volatile
719	>	* writes to be conservative.
720	>	*/
721	>
722	>	@SuppressWarnings("unchecked")
723	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
724	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
725	>	}
726	>
727	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
728	>	Node<K,V> c, Node<K,V> v) {
729	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
730	>	}
731	>
732	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
733	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
734	>	}
735
736		/* ---------------- Fields -------------- */
737
738		/**
739	<	* Mask value for indexing into segments. The upper bits of a
740	<	* key's hash code are used to choose the segment.
741	<	**/
742	<	private final int segmentMask;
739	>	* The array of bins. Lazily initialized upon first insertion.
740	>	* Size is always a power of two. Accessed directly by iterators.
741	>	*/
742	>	transient volatile Node<K,V>[] table;
743
744		/**
745	<	* Shift value for indexing within segments.
746	<	**/
747	<	private final int segmentShift;
745	>	* The next table to use; non-null only while resizing.
746	>	*/
747	>	private transient volatile Node<K,V>[] nextTable;
748
749		/**
750	<	* The segments, each of which is a specialized hash table
750	>	* Base counter value, used mainly when there is no contention,
751	>	* but also as a fallback during table initialization
752	>	* races. Updated via CAS.
753		*/
754	<	private final Segment[] segments;
754	>	private transient volatile long baseCount;
755
756	<	private transient Set<K> keySet;
757	<	private transient Set<Map.Entry<K,V>> entrySet;
758	<	private transient Collection<V> values;
756	>	/**
757	>	* Table initialization and resizing control.  When negative, the
758	>	* table is being initialized or resized: -1 for initialization,
759	>	* else -(1 + the number of active resizing threads).  Otherwise,
760	>	* when table is null, holds the initial table size to use upon
761	>	* creation, or 0 for default. After initialization, holds the
762	>	* next element count value upon which to resize the table.
763	>	*/
764	>	private transient volatile int sizeCtl;
765	>
766	>	/**
767	>	* The next table index (plus one) to split while resizing.
768	>	*/
769	>	private transient volatile int transferIndex;
770
771	<	/* ---------------- Small Utilities -------------- */
771	>	/**
772	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
773	>	*/
774	>	private transient volatile int cellsBusy;
775
776		/**
777	<	* Return a hash code for non-null Object x.
130	<	* Uses the same hash code spreader as most other j.u hash tables.
131	<	* @param x the object serving as a key
132	<	* @return the hash code
777	>	* Table of counter cells. When non-null, size is a power of 2.
778		*/
779	<	private static int hash(Object x) {
780	<	int h = x.hashCode();
781	<	h += ~(h << 9);
782	<	h ^=  (h >>> 14);
783	<	h +=  (h << 4);
784	<	h ^=  (h >>> 10);
779	>	private transient volatile CounterCell[] counterCells;
780	>
781	>	// views
782	>	private transient KeySetView<K,V> keySet;
783	>	private transient ValuesView<K,V> values;
784	>	private transient EntrySetView<K,V> entrySet;
785	>
786	>
787	>	/* ---------------- Public operations -------------- */
788	>
789	>	/**
790	>	* Creates a new, empty map with the default initial table size (16).
791	>	*/
792	>	public ConcurrentHashMap() {
793	>	}
794	>
795	>	/**
796	>	* Creates a new, empty map with an initial table size
797	>	* accommodating the specified number of elements without the need
798	>	* to dynamically resize.
799	>	*
800	>	* @param initialCapacity The implementation performs internal
801	>	* sizing to accommodate this many elements.
802	>	* @throws IllegalArgumentException if the initial capacity of
803	>	* elements is negative
804	>	*/
805	>	public ConcurrentHashMap(int initialCapacity) {
806	>	if (initialCapacity < 0)
807	>	throw new IllegalArgumentException();
808	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
809	>	MAXIMUM_CAPACITY :
810	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
811	>	this.sizeCtl = cap;
812	>	}
813	>
814	>	/**
815	>	* Creates a new map with the same mappings as the given map.
816	>	*
817	>	* @param m the map
818	>	*/
819	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
820	>	this.sizeCtl = DEFAULT_CAPACITY;
821	>	putAll(m);
822	>	}
823	>
824	>	/**
825	>	* Creates a new, empty map with an initial table size based on
826	>	* the given number of elements ({@code initialCapacity}) and
827	>	* initial table density ({@code loadFactor}).
828	>	*
829	>	* @param initialCapacity the initial capacity. The implementation
830	>	* performs internal sizing to accommodate this many elements,
831	>	* given the specified load factor.
832	>	* @param loadFactor the load factor (table density) for
833	>	* establishing the initial table size
834	>	* @throws IllegalArgumentException if the initial capacity of
835	>	* elements is negative or the load factor is nonpositive
836	>	*
837	>	* @since 1.6
838	>	*/
839	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
840	>	this(initialCapacity, loadFactor, 1);
841	>	}
842	>
843	>	/**
844	>	* Creates a new, empty map with an initial table size based on
845	>	* the given number of elements ({@code initialCapacity}), table
846	>	* density ({@code loadFactor}), and number of concurrently
847	>	* updating threads ({@code concurrencyLevel}).
848	>	*
849	>	* @param initialCapacity the initial capacity. The implementation
850	>	* performs internal sizing to accommodate this many elements,
851	>	* given the specified load factor.
852	>	* @param loadFactor the load factor (table density) for
853	>	* establishing the initial table size
854	>	* @param concurrencyLevel the estimated number of concurrently
855	>	* updating threads. The implementation may use this value as
856	>	* a sizing hint.
857	>	* @throws IllegalArgumentException if the initial capacity is
858	>	* negative or the load factor or concurrencyLevel are
859	>	* nonpositive
860	>	*/
861	>	public ConcurrentHashMap(int initialCapacity,
862	>	float loadFactor, int concurrencyLevel) {
863	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
864	>	throw new IllegalArgumentException();
865	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
866	>	initialCapacity = concurrencyLevel;   // as estimated threads
867	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
868	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
869	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
870	>	this.sizeCtl = cap;
871	>	}
872	>
873	>	// Original (since JDK1.2) Map methods
874	>
875	>	/**
876	>	* {@inheritDoc}
877	>	*/
878	>	public int size() {
879	>	long n = sumCount();
880	>	return ((n < 0L) ? 0 :
881	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
882	>	(int)n);
883	>	}
884	>
885	>	/**
886	>	* {@inheritDoc}
887	>	*/
888	>	public boolean isEmpty() {
889	>	return sumCount() <= 0L; // ignore transient negative values
890	>	}
891	>
892	>	/**
893	>	* Returns the value to which the specified key is mapped,
894	>	* or {@code null} if this map contains no mapping for the key.
895	>	*
896	>	* <p>More formally, if this map contains a mapping from a key
897	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
898	>	* then this method returns {@code v}; otherwise it returns
899	>	* {@code null}.  (There can be at most one such mapping.)
900	>	*
901	>	* @throws NullPointerException if the specified key is null
902	>	*/
903	>	public V get(Object key) {
904	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
905	>	int h = spread(key.hashCode());
906	>	if ((tab = table) != null && (n = tab.length) > 0 &&
907	>	(e = tabAt(tab, (n - 1) & h)) != null) {
908	>	if ((eh = e.hash) == h) {
909	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
910	>	return e.val;
911	>	}
912	>	else if (eh < 0)
913	>	return (p = e.find(h, key)) != null ? p.val : null;
914	>	while ((e = e.next) != null) {
915	>	if (e.hash == h &&
916	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
917	>	return e.val;
918	>	}
919	>	}
920	>	return null;
921	>	}
922	>
923	>	/**
924	>	* Tests if the specified object is a key in this table.
925	>	*
926	>	* @param  key possible key
927	>	* @return {@code true} if and only if the specified object
928	>	*         is a key in this table, as determined by the
929	>	*         {@code equals} method; {@code false} otherwise
930	>	* @throws NullPointerException if the specified key is null
931	>	*/
932	>	public boolean containsKey(Object key) {
933	>	return get(key) != null;
934	>	}
935	>
936	>	/**
937	>	* Returns {@code true} if this map maps one or more keys to the
938	>	* specified value. Note: This method may require a full traversal
939	>	* of the map, and is much slower than method {@code containsKey}.
940	>	*
941	>	* @param value value whose presence in this map is to be tested
942	>	* @return {@code true} if this map maps one or more keys to the
943	>	*         specified value
944	>	* @throws NullPointerException if the specified value is null
945	>	*/
946	>	public boolean containsValue(Object value) {
947	>	if (value == null)
948	>	throw new NullPointerException();
949	>	Node<K,V>[] t;
950	>	if ((t = table) != null) {
951	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
952	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
953	>	V v;
954	>	if ((v = p.val) == value || (v != null && value.equals(v)))
955	>	return true;
956	>	}
957	>	}
958	>	return false;
959	>	}
960	>
961	>	/**
962	>	* Maps the specified key to the specified value in this table.
963	>	* Neither the key nor the value can be null.
964	>	*
965	>	* <p>The value can be retrieved by calling the {@code get} method
966	>	* with a key that is equal to the original key.
967	>	*
968	>	* @param key key with which the specified value is to be associated
969	>	* @param value value to be associated with the specified key
970	>	* @return the previous value associated with {@code key}, or
971	>	*         {@code null} if there was no mapping for {@code key}
972	>	* @throws NullPointerException if the specified key or value is null
973	>	*/
974	>	public V put(K key, V value) {
975	>	return putVal(key, value, false);
976	>	}
977	>
978	>	/** Implementation for put and putIfAbsent */
979	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
980	>	if (key == null || value == null) throw new NullPointerException();
981	>	int hash = spread(key.hashCode());
982	>	int binCount = 0;
983	>	for (Node<K,V>[] tab = table;;) {
984	>	Node<K,V> f; int n, i, fh;
985	>	if (tab == null || (n = tab.length) == 0)
986	>	tab = initTable();
987	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
988	>	if (casTabAt(tab, i, null,
989	>	new Node<K,V>(hash, key, value, null)))
990	>	break;                   // no lock when adding to empty bin
991	>	}
992	>	else if ((fh = f.hash) == MOVED)
993	>	tab = helpTransfer(tab, f);
994	>	else {
995	>	V oldVal = null;
996	>	synchronized (f) {
997	>	if (tabAt(tab, i) == f) {
998	>	if (fh >= 0) {
999	>	binCount = 1;
1000	>	for (Node<K,V> e = f;; ++binCount) {
1001	>	K ek;
1002	>	if (e.hash == hash &&
1003	>	((ek = e.key) == key ||
1004	>	(ek != null && key.equals(ek)))) {
1005	>	oldVal = e.val;
1006	>	if (!onlyIfAbsent)
1007	>	e.val = value;
1008	>	break;
1009	>	}
1010	>	Node<K,V> pred = e;
1011	>	if ((e = e.next) == null) {
1012	>	pred.next = new Node<K,V>(hash, key,
1013	>	value, null);
1014	>	break;
1015	>	}
1016	>	}
1017	>	}
1018	>	else if (f instanceof TreeBin) {
1019	>	Node<K,V> p;
1020	>	binCount = 2;
1021	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1022	>	value)) != null) {
1023	>	oldVal = p.val;
1024	>	if (!onlyIfAbsent)
1025	>	p.val = value;
1026	>	}
1027	>	}
1028	>	else if (f instanceof ReservationNode)
1029	>	throw new IllegalStateException("Recursive update");
1030	>	}
1031	>	}
1032	>	if (binCount != 0) {
1033	>	if (binCount >= TREEIFY_THRESHOLD)
1034	>	treeifyBin(tab, i);
1035	>	if (oldVal != null)
1036	>	return oldVal;
1037	>	break;
1038	>	}
1039	>	}
1040	>	}
1041	>	addCount(1L, binCount);
1042	>	return null;
1043	>	}
1044	>
1045	>	/**
1046	>	* Copies all of the mappings from the specified map to this one.
1047	>	* These mappings replace any mappings that this map had for any of the
1048	>	* keys currently in the specified map.
1049	>	*
1050	>	* @param m mappings to be stored in this map
1051	>	*/
1052	>	public void putAll(Map<? extends K, ? extends V> m) {
1053	>	tryPresize(m.size());
1054	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1055	>	putVal(e.getKey(), e.getValue(), false);
1056	>	}
1057	>
1058	>	/**
1059	>	* Removes the key (and its corresponding value) from this map.
1060	>	* This method does nothing if the key is not in the map.
1061	>	*
1062	>	* @param  key the key that needs to be removed
1063	>	* @return the previous value associated with {@code key}, or
1064	>	*         {@code null} if there was no mapping for {@code key}
1065	>	* @throws NullPointerException if the specified key is null
1066	>	*/
1067	>	public V remove(Object key) {
1068	>	return replaceNode(key, null, null);
1069	>	}
1070	>
1071	>	/**
1072	>	* Implementation for the four public remove/replace methods:
1073	>	* Replaces node value with v, conditional upon match of cv if
1074	>	* non-null.  If resulting value is null, delete.
1075	>	*/
1076	>	final V replaceNode(Object key, V value, Object cv) {
1077	>	int hash = spread(key.hashCode());
1078	>	for (Node<K,V>[] tab = table;;) {
1079	>	Node<K,V> f; int n, i, fh;
1080	>	if (tab == null || (n = tab.length) == 0 ||
1081	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1082	>	break;
1083	>	else if ((fh = f.hash) == MOVED)
1084	>	tab = helpTransfer(tab, f);
1085	>	else {
1086	>	V oldVal = null;
1087	>	boolean validated = false;
1088	>	synchronized (f) {
1089	>	if (tabAt(tab, i) == f) {
1090	>	if (fh >= 0) {
1091	>	validated = true;
1092	>	for (Node<K,V> e = f, pred = null;;) {
1093	>	K ek;
1094	>	if (e.hash == hash &&
1095	>	((ek = e.key) == key ||
1096	>	(ek != null && key.equals(ek)))) {
1097	>	V ev = e.val;
1098	>	if (cv == null || cv == ev ||
1099	>	(ev != null && cv.equals(ev))) {
1100	>	oldVal = ev;
1101	>	if (value != null)
1102	>	e.val = value;
1103	>	else if (pred != null)
1104	>	pred.next = e.next;
1105	>	else
1106	>	setTabAt(tab, i, e.next);
1107	>	}
1108	>	break;
1109	>	}
1110	>	pred = e;
1111	>	if ((e = e.next) == null)
1112	>	break;
1113	>	}
1114	>	}
1115	>	else if (f instanceof TreeBin) {
1116	>	validated = true;
1117	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1118	>	TreeNode<K,V> r, p;
1119	>	if ((r = t.root) != null &&
1120	>	(p = r.findTreeNode(hash, key, null)) != null) {
1121	>	V pv = p.val;
1122	>	if (cv == null || cv == pv ||
1123	>	(pv != null && cv.equals(pv))) {
1124	>	oldVal = pv;
1125	>	if (value != null)
1126	>	p.val = value;
1127	>	else if (t.removeTreeNode(p))
1128	>	setTabAt(tab, i, untreeify(t.first));
1129	>	}
1130	>	}
1131	>	}
1132	>	else if (f instanceof ReservationNode)
1133	>	throw new IllegalStateException("Recursive update");
1134	>	}
1135	>	}
1136	>	if (validated) {
1137	>	if (oldVal != null) {
1138	>	if (value == null)
1139	>	addCount(-1L, -1);
1140	>	return oldVal;
1141	>	}
1142	>	break;
1143	>	}
1144	>	}
1145	>	}
1146	>	return null;
1147	>	}
1148	>
1149	>	/**
1150	>	* Removes all of the mappings from this map.
1151	>	*/
1152	>	public void clear() {
1153	>	long delta = 0L; // negative number of deletions
1154	>	int i = 0;
1155	>	Node<K,V>[] tab = table;
1156	>	while (tab != null && i < tab.length) {
1157	>	int fh;
1158	>	Node<K,V> f = tabAt(tab, i);
1159	>	if (f == null)
1160	>	++i;
1161	>	else if ((fh = f.hash) == MOVED) {
1162	>	tab = helpTransfer(tab, f);
1163	>	i = 0; // restart
1164	>	}
1165	>	else {
1166	>	synchronized (f) {
1167	>	if (tabAt(tab, i) == f) {
1168	>	Node<K,V> p = (fh >= 0 ? f :
1169	>	(f instanceof TreeBin) ?
1170	>	((TreeBin<K,V>)f).first : null);
1171	>	while (p != null) {
1172	>	--delta;
1173	>	p = p.next;
1174	>	}
1175	>	setTabAt(tab, i++, null);
1176	>	}
1177	>	}
1178	>	}
1179	>	}
1180	>	if (delta != 0L)
1181	>	addCount(delta, -1);
1182	>	}
1183	>
1184	>	/**
1185	>	* Returns a {@link Set} view of the keys contained in this map.
1186	>	* The set is backed by the map, so changes to the map are
1187	>	* reflected in the set, and vice-versa. The set supports element
1188	>	* removal, which removes the corresponding mapping from this map,
1189	>	* via the {@code Iterator.remove}, {@code Set.remove},
1190	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1191	>	* operations.  It does not support the {@code add} or
1192	>	* {@code addAll} operations.
1193	>	*
1194	>	* <p>The view's iterators and spliterators are
1195	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1196	>	*
1197	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1198	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1199	>	*
1200	>	* @return the set view
1201	>	*/
1202	>	public KeySetView<K,V> keySet() {
1203	>	KeySetView<K,V> ks;
1204	>	return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1205	>	}
1206	>
1207	>	/**
1208	>	* Returns a {@link Collection} view of the values contained in this map.
1209	>	* The collection is backed by the map, so changes to the map are
1210	>	* reflected in the collection, and vice-versa.  The collection
1211	>	* supports element removal, which removes the corresponding
1212	>	* mapping from this map, via the {@code Iterator.remove},
1213	>	* {@code Collection.remove}, {@code removeAll},
1214	>	* {@code retainAll}, and {@code clear} operations.  It does not
1215	>	* support the {@code add} or {@code addAll} operations.
1216	>	*
1217	>	* <p>The view's iterators and spliterators are
1218	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1219	>	*
1220	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1221	>	* and {@link Spliterator#NONNULL}.
1222	>	*
1223	>	* @return the collection view
1224	>	*/
1225	>	public Collection<V> values() {
1226	>	ValuesView<K,V> vs;
1227	>	return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1228	>	}
1229	>
1230	>	/**
1231	>	* Returns a {@link Set} view of the mappings contained in this map.
1232	>	* The set is backed by the map, so changes to the map are
1233	>	* reflected in the set, and vice-versa.  The set supports element
1234	>	* removal, which removes the corresponding mapping from the map,
1235	>	* via the {@code Iterator.remove}, {@code Set.remove},
1236	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1237	>	* operations.
1238	>	*
1239	>	* <p>The view's iterators and spliterators are
1240	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1241	>	*
1242	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1243	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1244	>	*
1245	>	* @return the set view
1246	>	*/
1247	>	public Set<Map.Entry<K,V>> entrySet() {
1248	>	EntrySetView<K,V> es;
1249	>	return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1250	>	}
1251	>
1252	>	/**
1253	>	* Returns the hash code value for this {@link Map}, i.e.,
1254	>	* the sum of, for each key-value pair in the map,
1255	>	* {@code key.hashCode() ^ value.hashCode()}.
1256	>	*
1257	>	* @return the hash code value for this map
1258	>	*/
1259	>	public int hashCode() {
1260	>	int h = 0;
1261	>	Node<K,V>[] t;
1262	>	if ((t = table) != null) {
1263	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1264	>	for (Node<K,V> p; (p = it.advance()) != null; )
1265	>	h += p.key.hashCode() ^ p.val.hashCode();
1266	>	}
1267		return h;
1268		}
1269
1270		/**
1271	<	* Return the segment that should be used for key with given hash
1271	>	* Returns a string representation of this map.  The string
1272	>	* representation consists of a list of key-value mappings (in no
1273	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1274	>	* mappings are separated by the characters {@code ", "} (comma
1275	>	* and space).  Each key-value mapping is rendered as the key
1276	>	* followed by an equals sign ("{@code =}") followed by the
1277	>	* associated value.
1278	>	*
1279	>	* @return a string representation of this map
1280	>	*/
1281	>	public String toString() {
1282	>	Node<K,V>[] t;
1283	>	int f = (t = table) == null ? 0 : t.length;
1284	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1285	>	StringBuilder sb = new StringBuilder();
1286	>	sb.append('{');
1287	>	Node<K,V> p;
1288	>	if ((p = it.advance()) != null) {
1289	>	for (;;) {
1290	>	K k = p.key;
1291	>	V v = p.val;
1292	>	sb.append(k == this ? "(this Map)" : k);
1293	>	sb.append('=');
1294	>	sb.append(v == this ? "(this Map)" : v);
1295	>	if ((p = it.advance()) == null)
1296	>	break;
1297	>	sb.append(',').append(' ');
1298	>	}
1299	>	}
1300	>	return sb.append('}').toString();
1301	>	}
1302	>
1303	>	/**
1304	>	* Compares the specified object with this map for equality.
1305	>	* Returns {@code true} if the given object is a map with the same
1306	>	* mappings as this map.  This operation may return misleading
1307	>	* results if either map is concurrently modified during execution
1308	>	* of this method.
1309	>	*
1310	>	* @param o object to be compared for equality with this map
1311	>	* @return {@code true} if the specified object is equal to this map
1312		*/
1313	<	private Segment<K,V> segmentFor(int hash) {
1314	<	return (Segment<K,V>) segments[(hash >>> segmentShift) & segmentMask];
1313	>	public boolean equals(Object o) {
1314	>	if (o != this) {
1315	>	if (!(o instanceof Map))
1316	>	return false;
1317	>	Map<?,?> m = (Map<?,?>) o;
1318	>	Node<K,V>[] t;
1319	>	int f = (t = table) == null ? 0 : t.length;
1320	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1321	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1322	>	V val = p.val;
1323	>	Object v = m.get(p.key);
1324	>	if (v == null || (v != val && !v.equals(val)))
1325	>	return false;
1326	>	}
1327	>	for (Map.Entry<?,?> e : m.entrySet()) {
1328	>	Object mk, mv, v;
1329	>	if ((mk = e.getKey()) == null ||
1330	>	(mv = e.getValue()) == null ||
1331	>	(v = get(mk)) == null ||
1332	>	(mv != v && !mv.equals(v)))
1333	>	return false;
1334	>	}
1335	>	}
1336	>	return true;
1337	>	}
1338	>
1339	>	/**
1340	>	* Stripped-down version of helper class used in previous version,
1341	>	* declared for the sake of serialization compatibility
1342	>	*/
1343	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1344	>	private static final long serialVersionUID = 2249069246763182397L;
1345	>	final float loadFactor;
1346	>	Segment(float lf) { this.loadFactor = lf; }
1347		}
1348
1349	<	/* ---------------- Inner Classes -------------- */
1349	>	/**
1350	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1351	>	* stream (i.e., serializes it).
1352	>	* @param s the stream
1353	>	* @throws java.io.IOException if an I/O error occurs
1354	>	* @serialData
1355	>	* the key (Object) and value (Object)
1356	>	* for each key-value mapping, followed by a null pair.
1357	>	* The key-value mappings are emitted in no particular order.
1358	>	*/
1359	>	private void writeObject(java.io.ObjectOutputStream s)
1360	>	throws java.io.IOException {
1361	>	// For serialization compatibility
1362	>	// Emulate segment calculation from previous version of this class
1363	>	int sshift = 0;
1364	>	int ssize = 1;
1365	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1366	>	++sshift;
1367	>	ssize <<= 1;
1368	>	}
1369	>	int segmentShift = 32 - sshift;
1370	>	int segmentMask = ssize - 1;
1371	>	@SuppressWarnings("unchecked")
1372	>	Segment<K,V>[] segments = (Segment<K,V>[])
1373	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1374	>	for (int i = 0; i < segments.length; ++i)
1375	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1376	>	s.putFields().put("segments", segments);
1377	>	s.putFields().put("segmentShift", segmentShift);
1378	>	s.putFields().put("segmentMask", segmentMask);
1379	>	s.writeFields();
1380	>
1381	>	Node<K,V>[] t;
1382	>	if ((t = table) != null) {
1383	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1384	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1385	>	s.writeObject(p.key);
1386	>	s.writeObject(p.val);
1387	>	}
1388	>	}
1389	>	s.writeObject(null);
1390	>	s.writeObject(null);
1391	>	segments = null; // throw away
1392	>	}
1393
1394		/**
1395	<	* Segments are specialized versions of hash tables.  This
1396	<	* subclasses from ReentrantLock opportunistically, just to
1397	<	* simplify some locking and avoid separate construction.
1398	<	**/
1399	<	private static final class Segment<K,V> extends ReentrantLock implements Serializable {
1395	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1396	>	* @param s the stream
1397	>	* @throws ClassNotFoundException if the class of a serialized object
1398	>	*         could not be found
1399	>	* @throws java.io.IOException if an I/O error occurs
1400	>	*/
1401	>	private void readObject(java.io.ObjectInputStream s)
1402	>	throws java.io.IOException, ClassNotFoundException {
1403		/*
1404	<	* Segments maintain a table of entry lists that are ALWAYS
1405	<	* kept in a consistent state, so can be read without locking.
1406	<	* Next fields of nodes are immutable (final).  All list
1407	<	* additions are performed at the front of each bin. This
1408	<	* makes it easy to check changes, and also fast to traverse.
164	<	* When nodes would otherwise be changed, new nodes are
165	<	* created to replace them. This works well for hash tables
166	<	* since the bin lists tend to be short. (The average length
167	<	* is less than two for the default load factor threshold.)
168	<	*
169	<	* Read operations can thus proceed without locking, but rely
170	<	* on a memory barrier to ensure that completed write
171	<	* operations performed by other threads are
172	<	* noticed. Conveniently, the "count" field, tracking the
173	<	* number of elements, can also serve as the volatile variable
174	<	* providing proper read/write barriers. This is convenient
175	<	* because this field needs to be read in many read operations
176	<	* anyway.
177	<	*
178	<	* Implementors note. The basic rules for all this are:
179	<	*
180	<	*   - All unsynchronized read operations must first read the
181	<	*     "count" field, and should not look at table entries if
182	<	*     it is 0.
183	<	*
184	<	*   - All synchronized write operations should write to
185	<	*     the "count" field after updating. The operations must not
186	<	*     take any action that could even momentarily cause
187	<	*     a concurrent read operation to see inconsistent
188	<	*     data. This is made easier by the nature of the read
189	<	*     operations in Map. For example, no operation
190	<	*     can reveal that the table has grown but the threshold
191	<	*     has not yet been updated, so there are no atomicity
192	<	*     requirements for this with respect to reads.
193	<	*
194	<	* As a guide, all critical volatile reads and writes are marked
195	<	* in code comments.
1404	>	* To improve performance in typical cases, we create nodes
1405	>	* while reading, then place in table once size is known.
1406	>	* However, we must also validate uniqueness and deal with
1407	>	* overpopulated bins while doing so, which requires
1408	>	* specialized versions of putVal mechanics.
1409		*/
1410	+	sizeCtl = -1; // force exclusion for table construction
1411	+	s.defaultReadObject();
1412	+	long size = 0L;
1413	+	Node<K,V> p = null;
1414	+	for (;;) {
1415	+	@SuppressWarnings("unchecked")
1416	+	K k = (K) s.readObject();
1417	+	@SuppressWarnings("unchecked")
1418	+	V v = (V) s.readObject();
1419	+	if (k != null && v != null) {
1420	+	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1421	+	++size;
1422	+	}
1423	+	else
1424	+	break;
1425	+	}
1426	+	if (size == 0L)
1427	+	sizeCtl = 0;
1428	+	else {
1429	+	int n;
1430	+	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1431	+	n = MAXIMUM_CAPACITY;
1432	+	else {
1433	+	int sz = (int)size;
1434	+	n = tableSizeFor(sz + (sz >>> 1) + 1);
1435	+	}
1436	+	@SuppressWarnings("unchecked")
1437	+	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1438	+	int mask = n - 1;
1439	+	long added = 0L;
1440	+	while (p != null) {
1441	+	boolean insertAtFront;
1442	+	Node<K,V> next = p.next, first;
1443	+	int h = p.hash, j = h & mask;
1444	+	if ((first = tabAt(tab, j)) == null)
1445	+	insertAtFront = true;
1446	+	else {
1447	+	K k = p.key;
1448	+	if (first.hash < 0) {
1449	+	TreeBin<K,V> t = (TreeBin<K,V>)first;
1450	+	if (t.putTreeVal(h, k, p.val) == null)
1451	+	++added;
1452	+	insertAtFront = false;
1453	+	}
1454	+	else {
1455	+	int binCount = 0;
1456	+	insertAtFront = true;
1457	+	Node<K,V> q; K qk;
1458	+	for (q = first; q != null; q = q.next) {
1459	+	if (q.hash == h &&
1460	+	((qk = q.key) == k ||
1461	+	(qk != null && k.equals(qk)))) {
1462	+	insertAtFront = false;
1463	+	break;
1464	+	}
1465	+	++binCount;
1466	+	}
1467	+	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1468	+	insertAtFront = false;
1469	+	++added;
1470	+	p.next = first;
1471	+	TreeNode<K,V> hd = null, tl = null;
1472	+	for (q = p; q != null; q = q.next) {
1473	+	TreeNode<K,V> t = new TreeNode<K,V>
1474	+	(q.hash, q.key, q.val, null, null);
1475	+	if ((t.prev = tl) == null)
1476	+	hd = t;
1477	+	else
1478	+	tl.next = t;
1479	+	tl = t;
1480	+	}
1481	+	setTabAt(tab, j, new TreeBin<K,V>(hd));
1482	+	}
1483	+	}
1484	+	}
1485	+	if (insertAtFront) {
1486	+	++added;
1487	+	p.next = first;
1488	+	setTabAt(tab, j, p);
1489	+	}
1490	+	p = next;
1491	+	}
1492	+	table = tab;
1493	+	sizeCtl = n - (n >>> 2);
1494	+	baseCount = added;
1495	+	}
1496	+	}
1497
1498	<	private static final long serialVersionUID = 2249069246763182397L;
1498	>	// ConcurrentMap methods
1499
1500	<	/**
1501	<	* The number of elements in this segment's region.
1502	<	**/
1503	<	transient volatile int count;
1500	>	/**
1501	>	* {@inheritDoc}
1502	>	*
1503	>	* @return the previous value associated with the specified key,
1504	>	*         or {@code null} if there was no mapping for the key
1505	>	* @throws NullPointerException if the specified key or value is null
1506	>	*/
1507	>	public V putIfAbsent(K key, V value) {
1508	>	return putVal(key, value, true);
1509	>	}
1510	>
1511	>	/**
1512	>	* {@inheritDoc}
1513	>	*
1514	>	* @throws NullPointerException if the specified key is null
1515	>	*/
1516	>	public boolean remove(Object key, Object value) {
1517	>	if (key == null)
1518	>	throw new NullPointerException();
1519	>	return value != null && replaceNode(key, null, value) != null;
1520	>	}
1521	>
1522	>	/**
1523	>	* {@inheritDoc}
1524	>	*
1525	>	* @throws NullPointerException if any of the arguments are null
1526	>	*/
1527	>	public boolean replace(K key, V oldValue, V newValue) {
1528	>	if (key == null || oldValue == null || newValue == null)
1529	>	throw new NullPointerException();
1530	>	return replaceNode(key, newValue, oldValue) != null;
1531	>	}
1532	>
1533	>	/**
1534	>	* {@inheritDoc}
1535	>	*
1536	>	* @return the previous value associated with the specified key,
1537	>	*         or {@code null} if there was no mapping for the key
1538	>	* @throws NullPointerException if the specified key or value is null
1539	>	*/
1540	>	public V replace(K key, V value) {
1541	>	if (key == null || value == null)
1542	>	throw new NullPointerException();
1543	>	return replaceNode(key, value, null);
1544	>	}
1545	>
1546	>	// Overrides of JDK8+ Map extension method defaults
1547	>
1548	>	/**
1549	>	* Returns the value to which the specified key is mapped, or the
1550	>	* given default value if this map contains no mapping for the
1551	>	* key.
1552	>	*
1553	>	* @param key the key whose associated value is to be returned
1554	>	* @param defaultValue the value to return if this map contains
1555	>	* no mapping for the given key
1556	>	* @return the mapping for the key, if present; else the default value
1557	>	* @throws NullPointerException if the specified key is null
1558	>	*/
1559	>	public V getOrDefault(Object key, V defaultValue) {
1560	>	V v;
1561	>	return (v = get(key)) == null ? defaultValue : v;
1562	>	}
1563	>
1564	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1565	>	if (action == null) throw new NullPointerException();
1566	>	Node<K,V>[] t;
1567	>	if ((t = table) != null) {
1568	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1569	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1570	>	action.accept(p.key, p.val);
1571	>	}
1572	>	}
1573	>	}
1574	>
1575	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1576	>	if (function == null) throw new NullPointerException();
1577	>	Node<K,V>[] t;
1578	>	if ((t = table) != null) {
1579	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1580	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1581	>	V oldValue = p.val;
1582	>	for (K key = p.key;;) {
1583	>	V newValue = function.apply(key, oldValue);
1584	>	if (newValue == null)
1585	>	throw new NullPointerException();
1586	>	if (replaceNode(key, newValue, oldValue) != null ||
1587	>	(oldValue = get(key)) == null)
1588	>	break;
1589	>	}
1590	>	}
1591	>	}
1592	>	}
1593	>
1594	>	/**
1595	>	* If the specified key is not already associated with a value,
1596	>	* attempts to compute its value using the given mapping function
1597	>	* and enters it into this map unless {@code null}.  The entire
1598	>	* method invocation is performed atomically, so the function is
1599	>	* applied at most once per key.  Some attempted update operations
1600	>	* on this map by other threads may be blocked while computation
1601	>	* is in progress, so the computation should be short and simple,
1602	>	* and must not attempt to update any other mappings of this map.
1603	>	*
1604	>	* @param key key with which the specified value is to be associated
1605	>	* @param mappingFunction the function to compute a value
1606	>	* @return the current (existing or computed) value associated with
1607	>	*         the specified key, or null if the computed value is null
1608	>	* @throws NullPointerException if the specified key or mappingFunction
1609	>	*         is null
1610	>	* @throws IllegalStateException if the computation detectably
1611	>	*         attempts a recursive update to this map that would
1612	>	*         otherwise never complete
1613	>	* @throws RuntimeException or Error if the mappingFunction does so,
1614	>	*         in which case the mapping is left unestablished
1615	>	*/
1616	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1617	>	if (key == null || mappingFunction == null)
1618	>	throw new NullPointerException();
1619	>	int h = spread(key.hashCode());
1620	>	V val = null;
1621	>	int binCount = 0;
1622	>	for (Node<K,V>[] tab = table;;) {
1623	>	Node<K,V> f; int n, i, fh;
1624	>	if (tab == null || (n = tab.length) == 0)
1625	>	tab = initTable();
1626	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1627	>	Node<K,V> r = new ReservationNode<K,V>();
1628	>	synchronized (r) {
1629	>	if (casTabAt(tab, i, null, r)) {
1630	>	binCount = 1;
1631	>	Node<K,V> node = null;
1632	>	try {
1633	>	if ((val = mappingFunction.apply(key)) != null)
1634	>	node = new Node<K,V>(h, key, val, null);
1635	>	} finally {
1636	>	setTabAt(tab, i, node);
1637	>	}
1638	>	}
1639	>	}
1640	>	if (binCount != 0)
1641	>	break;
1642	>	}
1643	>	else if ((fh = f.hash) == MOVED)
1644	>	tab = helpTransfer(tab, f);
1645	>	else {
1646	>	boolean added = false;
1647	>	synchronized (f) {
1648	>	if (tabAt(tab, i) == f) {
1649	>	if (fh >= 0) {
1650	>	binCount = 1;
1651	>	for (Node<K,V> e = f;; ++binCount) {
1652	>	K ek;
1653	>	if (e.hash == h &&
1654	>	((ek = e.key) == key ||
1655	>	(ek != null && key.equals(ek)))) {
1656	>	val = e.val;
1657	>	break;
1658	>	}
1659	>	Node<K,V> pred = e;
1660	>	if ((e = e.next) == null) {
1661	>	if ((val = mappingFunction.apply(key)) != null) {
1662	>	if (pred.next != null)
1663	>	throw new IllegalStateException("Recursive update");
1664	>	added = true;
1665	>	pred.next = new Node<K,V>(h, key, val, null);
1666	>	}
1667	>	break;
1668	>	}
1669	>	}
1670	>	}
1671	>	else if (f instanceof TreeBin) {
1672	>	binCount = 2;
1673	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1674	>	TreeNode<K,V> r, p;
1675	>	if ((r = t.root) != null &&
1676	>	(p = r.findTreeNode(h, key, null)) != null)
1677	>	val = p.val;
1678	>	else if ((val = mappingFunction.apply(key)) != null) {
1679	>	added = true;
1680	>	t.putTreeVal(h, key, val);
1681	>	}
1682	>	}
1683	>	else if (f instanceof ReservationNode)
1684	>	throw new IllegalStateException("Recursive update");
1685	>	}
1686	>	}
1687	>	if (binCount != 0) {
1688	>	if (binCount >= TREEIFY_THRESHOLD)
1689	>	treeifyBin(tab, i);
1690	>	if (!added)
1691	>	return val;
1692	>	break;
1693	>	}
1694	>	}
1695	>	}
1696	>	if (val != null)
1697	>	addCount(1L, binCount);
1698	>	return val;
1699	>	}
1700	>
1701	>	/**
1702	>	* If the value for the specified key is present, attempts to
1703	>	* compute a new mapping given the key and its current mapped
1704	>	* value.  The entire method invocation is performed atomically.
1705	>	* Some attempted update operations on this map by other threads
1706	>	* may be blocked while computation is in progress, so the
1707	>	* computation should be short and simple, and must not attempt to
1708	>	* update any other mappings of this map.
1709	>	*
1710	>	* @param key key with which a value may be associated
1711	>	* @param remappingFunction the function to compute a value
1712	>	* @return the new value associated with the specified key, or null if none
1713	>	* @throws NullPointerException if the specified key or remappingFunction
1714	>	*         is null
1715	>	* @throws IllegalStateException if the computation detectably
1716	>	*         attempts a recursive update to this map that would
1717	>	*         otherwise never complete
1718	>	* @throws RuntimeException or Error if the remappingFunction does so,
1719	>	*         in which case the mapping is unchanged
1720	>	*/
1721	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1722	>	if (key == null || remappingFunction == null)
1723	>	throw new NullPointerException();
1724	>	int h = spread(key.hashCode());
1725	>	V val = null;
1726	>	int delta = 0;
1727	>	int binCount = 0;
1728	>	for (Node<K,V>[] tab = table;;) {
1729	>	Node<K,V> f; int n, i, fh;
1730	>	if (tab == null || (n = tab.length) == 0)
1731	>	tab = initTable();
1732	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1733	>	break;
1734	>	else if ((fh = f.hash) == MOVED)
1735	>	tab = helpTransfer(tab, f);
1736	>	else {
1737	>	synchronized (f) {
1738	>	if (tabAt(tab, i) == f) {
1739	>	if (fh >= 0) {
1740	>	binCount = 1;
1741	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1742	>	K ek;
1743	>	if (e.hash == h &&
1744	>	((ek = e.key) == key ||
1745	>	(ek != null && key.equals(ek)))) {
1746	>	val = remappingFunction.apply(key, e.val);
1747	>	if (val != null)
1748	>	e.val = val;
1749	>	else {
1750	>	delta = -1;
1751	>	Node<K,V> en = e.next;
1752	>	if (pred != null)
1753	>	pred.next = en;
1754	>	else
1755	>	setTabAt(tab, i, en);
1756	>	}
1757	>	break;
1758	>	}
1759	>	pred = e;
1760	>	if ((e = e.next) == null)
1761	>	break;
1762	>	}
1763	>	}
1764	>	else if (f instanceof TreeBin) {
1765	>	binCount = 2;
1766	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1767	>	TreeNode<K,V> r, p;
1768	>	if ((r = t.root) != null &&
1769	>	(p = r.findTreeNode(h, key, null)) != null) {
1770	>	val = remappingFunction.apply(key, p.val);
1771	>	if (val != null)
1772	>	p.val = val;
1773	>	else {
1774	>	delta = -1;
1775	>	if (t.removeTreeNode(p))
1776	>	setTabAt(tab, i, untreeify(t.first));
1777	>	}
1778	>	}
1779	>	}
1780	>	else if (f instanceof ReservationNode)
1781	>	throw new IllegalStateException("Recursive update");
1782	>	}
1783	>	}
1784	>	if (binCount != 0)
1785	>	break;
1786	>	}
1787	>	}
1788	>	if (delta != 0)
1789	>	addCount((long)delta, binCount);
1790	>	return val;
1791	>	}
1792	>
1793	>	/**
1794	>	* Attempts to compute a mapping for the specified key and its
1795	>	* current mapped value (or {@code null} if there is no current
1796	>	* mapping). The entire method invocation is performed atomically.
1797	>	* Some attempted update operations on this map by other threads
1798	>	* may be blocked while computation is in progress, so the
1799	>	* computation should be short and simple, and must not attempt to
1800	>	* update any other mappings of this Map.
1801	>	*
1802	>	* @param key key with which the specified value is to be associated
1803	>	* @param remappingFunction the function to compute a value
1804	>	* @return the new value associated with the specified key, or null if none
1805	>	* @throws NullPointerException if the specified key or remappingFunction
1806	>	*         is null
1807	>	* @throws IllegalStateException if the computation detectably
1808	>	*         attempts a recursive update to this map that would
1809	>	*         otherwise never complete
1810	>	* @throws RuntimeException or Error if the remappingFunction does so,
1811	>	*         in which case the mapping is unchanged
1812	>	*/
1813	>	public V compute(K key,
1814	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1815	>	if (key == null || remappingFunction == null)
1816	>	throw new NullPointerException();
1817	>	int h = spread(key.hashCode());
1818	>	V val = null;
1819	>	int delta = 0;
1820	>	int binCount = 0;
1821	>	for (Node<K,V>[] tab = table;;) {
1822	>	Node<K,V> f; int n, i, fh;
1823	>	if (tab == null || (n = tab.length) == 0)
1824	>	tab = initTable();
1825	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1826	>	Node<K,V> r = new ReservationNode<K,V>();
1827	>	synchronized (r) {
1828	>	if (casTabAt(tab, i, null, r)) {
1829	>	binCount = 1;
1830	>	Node<K,V> node = null;
1831	>	try {
1832	>	if ((val = remappingFunction.apply(key, null)) != null) {
1833	>	delta = 1;
1834	>	node = new Node<K,V>(h, key, val, null);
1835	>	}
1836	>	} finally {
1837	>	setTabAt(tab, i, node);
1838	>	}
1839	>	}
1840	>	}
1841	>	if (binCount != 0)
1842	>	break;
1843	>	}
1844	>	else if ((fh = f.hash) == MOVED)
1845	>	tab = helpTransfer(tab, f);
1846	>	else {
1847	>	synchronized (f) {
1848	>	if (tabAt(tab, i) == f) {
1849	>	if (fh >= 0) {
1850	>	binCount = 1;
1851	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1852	>	K ek;
1853	>	if (e.hash == h &&
1854	>	((ek = e.key) == key ||
1855	>	(ek != null && key.equals(ek)))) {
1856	>	val = remappingFunction.apply(key, e.val);
1857	>	if (val != null)
1858	>	e.val = val;
1859	>	else {
1860	>	delta = -1;
1861	>	Node<K,V> en = e.next;
1862	>	if (pred != null)
1863	>	pred.next = en;
1864	>	else
1865	>	setTabAt(tab, i, en);
1866	>	}
1867	>	break;
1868	>	}
1869	>	pred = e;
1870	>	if ((e = e.next) == null) {
1871	>	val = remappingFunction.apply(key, null);
1872	>	if (val != null) {
1873	>	if (pred.next != null)
1874	>	throw new IllegalStateException("Recursive update");
1875	>	delta = 1;
1876	>	pred.next =
1877	>	new Node<K,V>(h, key, val, null);
1878	>	}
1879	>	break;
1880	>	}
1881	>	}
1882	>	}
1883	>	else if (f instanceof TreeBin) {
1884	>	binCount = 1;
1885	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1886	>	TreeNode<K,V> r, p;
1887	>	if ((r = t.root) != null)
1888	>	p = r.findTreeNode(h, key, null);
1889	>	else
1890	>	p = null;
1891	>	V pv = (p == null) ? null : p.val;
1892	>	val = remappingFunction.apply(key, pv);
1893	>	if (val != null) {
1894	>	if (p != null)
1895	>	p.val = val;
1896	>	else {
1897	>	delta = 1;
1898	>	t.putTreeVal(h, key, val);
1899	>	}
1900	>	}
1901	>	else if (p != null) {
1902	>	delta = -1;
1903	>	if (t.removeTreeNode(p))
1904	>	setTabAt(tab, i, untreeify(t.first));
1905	>	}
1906	>	}
1907	>	else if (f instanceof ReservationNode)
1908	>	throw new IllegalStateException("Recursive update");
1909	>	}
1910	>	}
1911	>	if (binCount != 0) {
1912	>	if (binCount >= TREEIFY_THRESHOLD)
1913	>	treeifyBin(tab, i);
1914	>	break;
1915	>	}
1916	>	}
1917	>	}
1918	>	if (delta != 0)
1919	>	addCount((long)delta, binCount);
1920	>	return val;
1921	>	}
1922	>
1923	>	/**
1924	>	* If the specified key is not already associated with a
1925	>	* (non-null) value, associates it with the given value.
1926	>	* Otherwise, replaces the value with the results of the given
1927	>	* remapping function, or removes if {@code null}. The entire
1928	>	* method invocation is performed atomically.  Some attempted
1929	>	* update operations on this map by other threads may be blocked
1930	>	* while computation is in progress, so the computation should be
1931	>	* short and simple, and must not attempt to update any other
1932	>	* mappings of this Map.
1933	>	*
1934	>	* @param key key with which the specified value is to be associated
1935	>	* @param value the value to use if absent
1936	>	* @param remappingFunction the function to recompute a value if present
1937	>	* @return the new value associated with the specified key, or null if none
1938	>	* @throws NullPointerException if the specified key or the
1939	>	*         remappingFunction is null
1940	>	* @throws RuntimeException or Error if the remappingFunction does so,
1941	>	*         in which case the mapping is unchanged
1942	>	*/
1943	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1944	>	if (key == null || value == null || remappingFunction == null)
1945	>	throw new NullPointerException();
1946	>	int h = spread(key.hashCode());
1947	>	V val = null;
1948	>	int delta = 0;
1949	>	int binCount = 0;
1950	>	for (Node<K,V>[] tab = table;;) {
1951	>	Node<K,V> f; int n, i, fh;
1952	>	if (tab == null || (n = tab.length) == 0)
1953	>	tab = initTable();
1954	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1955	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1956	>	delta = 1;
1957	>	val = value;
1958	>	break;
1959	>	}
1960	>	}
1961	>	else if ((fh = f.hash) == MOVED)
1962	>	tab = helpTransfer(tab, f);
1963	>	else {
1964	>	synchronized (f) {
1965	>	if (tabAt(tab, i) == f) {
1966	>	if (fh >= 0) {
1967	>	binCount = 1;
1968	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1969	>	K ek;
1970	>	if (e.hash == h &&
1971	>	((ek = e.key) == key ||
1972	>	(ek != null && key.equals(ek)))) {
1973	>	val = remappingFunction.apply(e.val, value);
1974	>	if (val != null)
1975	>	e.val = val;
1976	>	else {
1977	>	delta = -1;
1978	>	Node<K,V> en = e.next;
1979	>	if (pred != null)
1980	>	pred.next = en;
1981	>	else
1982	>	setTabAt(tab, i, en);
1983	>	}
1984	>	break;
1985	>	}
1986	>	pred = e;
1987	>	if ((e = e.next) == null) {
1988	>	delta = 1;
1989	>	val = value;
1990	>	pred.next =
1991	>	new Node<K,V>(h, key, val, null);
1992	>	break;
1993	>	}
1994	>	}
1995	>	}
1996	>	else if (f instanceof TreeBin) {
1997	>	binCount = 2;
1998	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1999	>	TreeNode<K,V> r = t.root;
2000	>	TreeNode<K,V> p = (r == null) ? null :
2001	>	r.findTreeNode(h, key, null);
2002	>	val = (p == null) ? value :
2003	>	remappingFunction.apply(p.val, value);
2004	>	if (val != null) {
2005	>	if (p != null)
2006	>	p.val = val;
2007	>	else {
2008	>	delta = 1;
2009	>	t.putTreeVal(h, key, val);
2010	>	}
2011	>	}
2012	>	else if (p != null) {
2013	>	delta = -1;
2014	>	if (t.removeTreeNode(p))
2015	>	setTabAt(tab, i, untreeify(t.first));
2016	>	}
2017	>	}
2018	>	else if (f instanceof ReservationNode)
2019	>	throw new IllegalStateException("Recursive update");
2020	>	}
2021	>	}
2022	>	if (binCount != 0) {
2023	>	if (binCount >= TREEIFY_THRESHOLD)
2024	>	treeifyBin(tab, i);
2025	>	break;
2026	>	}
2027	>	}
2028	>	}
2029	>	if (delta != 0)
2030	>	addCount((long)delta, binCount);
2031	>	return val;
2032	>	}
2033	>
2034	>	// Hashtable legacy methods
2035	>
2036	>	/**
2037	>	* Legacy method testing if some key maps into the specified value
2038	>	* in this table.
2039	>	*
2040	>	* @deprecated This method is identical in functionality to
2041	>	* {@link #containsValue(Object)}, and exists solely to ensure
2042	>	* full compatibility with class {@link java.util.Hashtable},
2043	>	* which supported this method prior to introduction of the
2044	>	* Java Collections framework.
2045	>	*
2046	>	* @param  value a value to search for
2047	>	* @return {@code true} if and only if some key maps to the
2048	>	*         {@code value} argument in this table as
2049	>	*         determined by the {@code equals} method;
2050	>	*         {@code false} otherwise
2051	>	* @throws NullPointerException if the specified value is null
2052	>	*/
2053	>	@Deprecated
2054	>	public boolean contains(Object value) {
2055	>	return containsValue(value);
2056	>	}
2057	>
2058	>	/**
2059	>	* Returns an enumeration of the keys in this table.
2060	>	*
2061	>	* @return an enumeration of the keys in this table
2062	>	* @see #keySet()
2063	>	*/
2064	>	public Enumeration<K> keys() {
2065	>	Node<K,V>[] t;
2066	>	int f = (t = table) == null ? 0 : t.length;
2067	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2068	>	}
2069	>
2070	>	/**
2071	>	* Returns an enumeration of the values in this table.
2072	>	*
2073	>	* @return an enumeration of the values in this table
2074	>	* @see #values()
2075	>	*/
2076	>	public Enumeration<V> elements() {
2077	>	Node<K,V>[] t;
2078	>	int f = (t = table) == null ? 0 : t.length;
2079	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2080	>	}
2081	>
2082	>	// ConcurrentHashMap-only methods
2083	>
2084	>	/**
2085	>	* Returns the number of mappings. This method should be used
2086	>	* instead of {@link #size} because a ConcurrentHashMap may
2087	>	* contain more mappings than can be represented as an int. The
2088	>	* value returned is an estimate; the actual count may differ if
2089	>	* there are concurrent insertions or removals.
2090	>	*
2091	>	* @return the number of mappings
2092	>	* @since 1.8
2093	>	*/
2094	>	public long mappingCount() {
2095	>	long n = sumCount();
2096	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2097	>	}
2098	>
2099	>	/**
2100	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2101	>	* from the given type to {@code Boolean.TRUE}.
2102	>	*
2103	>	* @param <K> the element type of the returned set
2104	>	* @return the new set
2105	>	* @since 1.8
2106	>	*/
2107	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2108	>	return new KeySetView<K,Boolean>
2109	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2110	>	}
2111	>
2112	>	/**
2113	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2114	>	* from the given type to {@code Boolean.TRUE}.
2115	>	*
2116	>	* @param initialCapacity The implementation performs internal
2117	>	* sizing to accommodate this many elements.
2118	>	* @param <K> the element type of the returned set
2119	>	* @return the new set
2120	>	* @throws IllegalArgumentException if the initial capacity of
2121	>	* elements is negative
2122	>	* @since 1.8
2123	>	*/
2124	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2125	>	return new KeySetView<K,Boolean>
2126	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2127	>	}
2128	>
2129	>	/**
2130	>	* Returns a {@link Set} view of the keys in this map, using the
2131	>	* given common mapped value for any additions (i.e., {@link
2132	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2133	>	* This is of course only appropriate if it is acceptable to use
2134	>	* the same value for all additions from this view.
2135	>	*
2136	>	* @param mappedValue the mapped value to use for any additions
2137	>	* @return the set view
2138	>	* @throws NullPointerException if the mappedValue is null
2139	>	*/
2140	>	public KeySetView<K,V> keySet(V mappedValue) {
2141	>	if (mappedValue == null)
2142	>	throw new NullPointerException();
2143	>	return new KeySetView<K,V>(this, mappedValue);
2144	>	}
2145	>
2146	>	/* ---------------- Special Nodes -------------- */
2147	>
2148	>	/**
2149	>	* A node inserted at head of bins during transfer operations.
2150	>	*/
2151	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2152	>	final Node<K,V>[] nextTable;
2153	>	ForwardingNode(Node<K,V>[] tab) {
2154	>	super(MOVED, null, null, null);
2155	>	this.nextTable = tab;
2156	>	}
2157	>
2158	>	Node<K,V> find(int h, Object k) {
2159	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2160	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2161	>	Node<K,V> e; int n;
2162	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2163	>	(e = tabAt(tab, (n - 1) & h)) == null)
2164	>	return null;
2165	>	for (;;) {
2166	>	int eh; K ek;
2167	>	if ((eh = e.hash) == h &&
2168	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2169	>	return e;
2170	>	if (eh < 0) {
2171	>	if (e instanceof ForwardingNode) {
2172	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2173	>	continue outer;
2174	>	}
2175	>	else
2176	>	return e.find(h, k);
2177	>	}
2178	>	if ((e = e.next) == null)
2179	>	return null;
2180	>	}
2181	>	}
2182	>	}
2183	>	}
2184	>
2185	>	/**
2186	>	* A place-holder node used in computeIfAbsent and compute
2187	>	*/
2188	>	static final class ReservationNode<K,V> extends Node<K,V> {
2189	>	ReservationNode() {
2190	>	super(RESERVED, null, null, null);
2191	>	}
2192	>
2193	>	Node<K,V> find(int h, Object k) {
2194	>	return null;
2195	>	}
2196	>	}
2197	>
2198	>	/* ---------------- Table Initialization and Resizing -------------- */
2199	>
2200	>	/**
2201	>	* Returns the stamp bits for resizing a table of size n.
2202	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2203	>	*/
2204	>	static final int resizeStamp(int n) {
2205	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2206	>	}
2207	>
2208	>	/**
2209	>	* Initializes table, using the size recorded in sizeCtl.
2210	>	*/
2211	>	private final Node<K,V>[] initTable() {
2212	>	Node<K,V>[] tab; int sc;
2213	>	while ((tab = table) == null || tab.length == 0) {
2214	>	if ((sc = sizeCtl) < 0)
2215	>	Thread.yield(); // lost initialization race; just spin
2216	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2217	>	try {
2218	>	if ((tab = table) == null || tab.length == 0) {
2219	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2220	>	@SuppressWarnings("unchecked")
2221	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2222	>	table = tab = nt;
2223	>	sc = n - (n >>> 2);
2224	>	}
2225	>	} finally {
2226	>	sizeCtl = sc;
2227	>	}
2228	>	break;
2229	>	}
2230	>	}
2231	>	return tab;
2232	>	}
2233	>
2234	>	/**
2235	>	* Adds to count, and if table is too small and not already
2236	>	* resizing, initiates transfer. If already resizing, helps
2237	>	* perform transfer if work is available.  Rechecks occupancy
2238	>	* after a transfer to see if another resize is already needed
2239	>	* because resizings are lagging additions.
2240	>	*
2241	>	* @param x the count to add
2242	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2243	>	*/
2244	>	private final void addCount(long x, int check) {
2245	>	CounterCell[] as; long b, s;
2246	>	if ((as = counterCells) != null ||
2247	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2248	>	CounterCell a; long v; int m;
2249	>	boolean uncontended = true;
2250	>	if (as == null || (m = as.length - 1) < 0 ||
2251	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2252	>	!(uncontended =
2253	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2254	>	fullAddCount(x, uncontended);
2255	>	return;
2256	>	}
2257	>	if (check <= 1)
2258	>	return;
2259	>	s = sumCount();
2260	>	}
2261	>	if (check >= 0) {
2262	>	Node<K,V>[] tab, nt; int n, sc;
2263	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2264	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2265	>	int rs = resizeStamp(n);
2266	>	if (sc < 0) {
2267	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2268	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2269	>	transferIndex <= 0)
2270	>	break;
2271	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2272	>	transfer(tab, nt);
2273	>	}
2274	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2275	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2276	>	transfer(tab, null);
2277	>	s = sumCount();
2278	>	}
2279	>	}
2280	>	}
2281	>
2282	>	/**
2283	>	* Helps transfer if a resize is in progress.
2284	>	*/
2285	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2286	>	Node<K,V>[] nextTab; int sc;
2287	>	if (tab != null && (f instanceof ForwardingNode) &&
2288	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2289	>	int rs = resizeStamp(tab.length);
2290	>	while (nextTab == nextTable && table == tab &&
2291	>	(sc = sizeCtl) < 0) {
2292	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2293	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2294	>	break;
2295	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2296	>	transfer(tab, nextTab);
2297	>	break;
2298	>	}
2299	>	}
2300	>	return nextTab;
2301	>	}
2302	>	return table;
2303	>	}
2304	>
2305	>	/**
2306	>	* Tries to presize table to accommodate the given number of elements.
2307	>	*
2308	>	* @param size number of elements (doesn't need to be perfectly accurate)
2309	>	*/
2310	>	private final void tryPresize(int size) {
2311	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2312	>	tableSizeFor(size + (size >>> 1) + 1);
2313	>	int sc;
2314	>	while ((sc = sizeCtl) >= 0) {
2315	>	Node<K,V>[] tab = table; int n;
2316	>	if (tab == null || (n = tab.length) == 0) {
2317	>	n = (sc > c) ? sc : c;
2318	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2319	>	try {
2320	>	if (table == tab) {
2321	>	@SuppressWarnings("unchecked")
2322	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2323	>	table = nt;
2324	>	sc = n - (n >>> 2);
2325	>	}
2326	>	} finally {
2327	>	sizeCtl = sc;
2328	>	}
2329	>	}
2330	>	}
2331	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2332	>	break;
2333	>	else if (tab == table) {
2334	>	int rs = resizeStamp(n);
2335	>	if (U.compareAndSwapInt(this, SIZECTL, sc,
2336	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2337	>	transfer(tab, null);
2338	>	}
2339	>	}
2340	>	}
2341	>
2342	>	/**
2343	>	* Moves and/or copies the nodes in each bin to new table. See
2344	>	* above for explanation.
2345	>	*/
2346	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2347	>	int n = tab.length, stride;
2348	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2349	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2350	>	if (nextTab == null) {            // initiating
2351	>	try {
2352	>	@SuppressWarnings("unchecked")
2353	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2354	>	nextTab = nt;
2355	>	} catch (Throwable ex) {      // try to cope with OOME
2356	>	sizeCtl = Integer.MAX_VALUE;
2357	>	return;
2358	>	}
2359	>	nextTable = nextTab;
2360	>	transferIndex = n;
2361	>	}
2362	>	int nextn = nextTab.length;
2363	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2364	>	boolean advance = true;
2365	>	boolean finishing = false; // to ensure sweep before committing nextTab
2366	>	for (int i = 0, bound = 0;;) {
2367	>	Node<K,V> f; int fh;
2368	>	while (advance) {
2369	>	int nextIndex, nextBound;
2370	>	if (--i >= bound || finishing)
2371	>	advance = false;
2372	>	else if ((nextIndex = transferIndex) <= 0) {
2373	>	i = -1;
2374	>	advance = false;
2375	>	}
2376	>	else if (U.compareAndSwapInt
2377	>	(this, TRANSFERINDEX, nextIndex,
2378	>	nextBound = (nextIndex > stride ?
2379	>	nextIndex - stride : 0))) {
2380	>	bound = nextBound;
2381	>	i = nextIndex - 1;
2382	>	advance = false;
2383	>	}
2384	>	}
2385	>	if (i < 0 || i >= n || i + n >= nextn) {
2386	>	int sc;
2387	>	if (finishing) {
2388	>	nextTable = null;
2389	>	table = nextTab;
2390	>	sizeCtl = (n << 1) - (n >>> 1);
2391	>	return;
2392	>	}
2393	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2394	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2395	>	return;
2396	>	finishing = advance = true;
2397	>	i = n; // recheck before commit
2398	>	}
2399	>	}
2400	>	else if ((f = tabAt(tab, i)) == null)
2401	>	advance = casTabAt(tab, i, null, fwd);
2402	>	else if ((fh = f.hash) == MOVED)
2403	>	advance = true; // already processed
2404	>	else {
2405	>	synchronized (f) {
2406	>	if (tabAt(tab, i) == f) {
2407	>	Node<K,V> ln, hn;
2408	>	if (fh >= 0) {
2409	>	int runBit = fh & n;
2410	>	Node<K,V> lastRun = f;
2411	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2412	>	int b = p.hash & n;
2413	>	if (b != runBit) {
2414	>	runBit = b;
2415	>	lastRun = p;
2416	>	}
2417	>	}
2418	>	if (runBit == 0) {
2419	>	ln = lastRun;
2420	>	hn = null;
2421	>	}
2422	>	else {
2423	>	hn = lastRun;
2424	>	ln = null;
2425	>	}
2426	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2427	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2428	>	if ((ph & n) == 0)
2429	>	ln = new Node<K,V>(ph, pk, pv, ln);
2430	>	else
2431	>	hn = new Node<K,V>(ph, pk, pv, hn);
2432	>	}
2433	>	setTabAt(nextTab, i, ln);
2434	>	setTabAt(nextTab, i + n, hn);
2435	>	setTabAt(tab, i, fwd);
2436	>	advance = true;
2437	>	}
2438	>	else if (f instanceof TreeBin) {
2439	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2440	>	TreeNode<K,V> lo = null, loTail = null;
2441	>	TreeNode<K,V> hi = null, hiTail = null;
2442	>	int lc = 0, hc = 0;
2443	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2444	>	int h = e.hash;
2445	>	TreeNode<K,V> p = new TreeNode<K,V>
2446	>	(h, e.key, e.val, null, null);
2447	>	if ((h & n) == 0) {
2448	>	if ((p.prev = loTail) == null)
2449	>	lo = p;
2450	>	else
2451	>	loTail.next = p;
2452	>	loTail = p;
2453	>	++lc;
2454	>	}
2455	>	else {
2456	>	if ((p.prev = hiTail) == null)
2457	>	hi = p;
2458	>	else
2459	>	hiTail.next = p;
2460	>	hiTail = p;
2461	>	++hc;
2462	>	}
2463	>	}
2464	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2465	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2466	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2467	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2468	>	setTabAt(nextTab, i, ln);
2469	>	setTabAt(nextTab, i + n, hn);
2470	>	setTabAt(tab, i, fwd);
2471	>	advance = true;
2472	>	}
2473	>	}
2474	>	}
2475	>	}
2476	>	}
2477	>	}
2478	>
2479	>	/* ---------------- Counter support -------------- */
2480	>
2481	>	/**
2482	>	* A padded cell for distributing counts.  Adapted from LongAdder
2483	>	* and Striped64.  See their internal docs for explanation.
2484	>	*/
2485	>	@sun.misc.Contended static final class CounterCell {
2486	>	volatile long value;
2487	>	CounterCell(long x) { value = x; }
2488	>	}
2489	>
2490	>	final long sumCount() {
2491	>	CounterCell[] as = counterCells; CounterCell a;
2492	>	long sum = baseCount;
2493	>	if (as != null) {
2494	>	for (int i = 0; i < as.length; ++i) {
2495	>	if ((a = as[i]) != null)
2496	>	sum += a.value;
2497	>	}
2498	>	}
2499	>	return sum;
2500	>	}
2501	>
2502	>	// See LongAdder version for explanation
2503	>	private final void fullAddCount(long x, boolean wasUncontended) {
2504	>	int h;
2505	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2506	>	ThreadLocalRandom.localInit();      // force initialization
2507	>	h = ThreadLocalRandom.getProbe();
2508	>	wasUncontended = true;
2509	>	}
2510	>	boolean collide = false;                // True if last slot nonempty
2511	>	for (;;) {
2512	>	CounterCell[] as; CounterCell a; int n; long v;
2513	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2514	>	if ((a = as[(n - 1) & h]) == null) {
2515	>	if (cellsBusy == 0) {            // Try to attach new Cell
2516	>	CounterCell r = new CounterCell(x); // Optimistic create
2517	>	if (cellsBusy == 0 &&
2518	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2519	>	boolean created = false;
2520	>	try {               // Recheck under lock
2521	>	CounterCell[] rs; int m, j;
2522	>	if ((rs = counterCells) != null &&
2523	>	(m = rs.length) > 0 &&
2524	>	rs[j = (m - 1) & h] == null) {
2525	>	rs[j] = r;
2526	>	created = true;
2527	>	}
2528	>	} finally {
2529	>	cellsBusy = 0;
2530	>	}
2531	>	if (created)
2532	>	break;
2533	>	continue;           // Slot is now non-empty
2534	>	}
2535	>	}
2536	>	collide = false;
2537	>	}
2538	>	else if (!wasUncontended)       // CAS already known to fail
2539	>	wasUncontended = true;      // Continue after rehash
2540	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2541	>	break;
2542	>	else if (counterCells != as || n >= NCPU)
2543	>	collide = false;            // At max size or stale
2544	>	else if (!collide)
2545	>	collide = true;
2546	>	else if (cellsBusy == 0 &&
2547	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2548	>	try {
2549	>	if (counterCells == as) {// Expand table unless stale
2550	>	CounterCell[] rs = new CounterCell[n << 1];
2551	>	for (int i = 0; i < n; ++i)
2552	>	rs[i] = as[i];
2553	>	counterCells = rs;
2554	>	}
2555	>	} finally {
2556	>	cellsBusy = 0;
2557	>	}
2558	>	collide = false;
2559	>	continue;                   // Retry with expanded table
2560	>	}
2561	>	h = ThreadLocalRandom.advanceProbe(h);
2562	>	}
2563	>	else if (cellsBusy == 0 && counterCells == as &&
2564	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2565	>	boolean init = false;
2566	>	try {                           // Initialize table
2567	>	if (counterCells == as) {
2568	>	CounterCell[] rs = new CounterCell[2];
2569	>	rs[h & 1] = new CounterCell(x);
2570	>	counterCells = rs;
2571	>	init = true;
2572	>	}
2573	>	} finally {
2574	>	cellsBusy = 0;
2575	>	}
2576	>	if (init)
2577	>	break;
2578	>	}
2579	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2580	>	break;                          // Fall back on using base
2581	>	}
2582	>	}
2583	>
2584	>	/* ---------------- Conversion from/to TreeBins -------------- */
2585	>
2586	>	/**
2587	>	* Replaces all linked nodes in bin at given index unless table is
2588	>	* too small, in which case resizes instead.
2589	>	*/
2590	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2591	>	Node<K,V> b; int n, sc;
2592	>	if (tab != null) {
2593	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2594	>	tryPresize(n << 1);
2595	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2596	>	synchronized (b) {
2597	>	if (tabAt(tab, index) == b) {
2598	>	TreeNode<K,V> hd = null, tl = null;
2599	>	for (Node<K,V> e = b; e != null; e = e.next) {
2600	>	TreeNode<K,V> p =
2601	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2602	>	null, null);
2603	>	if ((p.prev = tl) == null)
2604	>	hd = p;
2605	>	else
2606	>	tl.next = p;
2607	>	tl = p;
2608	>	}
2609	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2610	>	}
2611	>	}
2612	>	}
2613	>	}
2614	>	}
2615	>
2616	>	/**
2617	>	* Returns a list on non-TreeNodes replacing those in given list.
2618	>	*/
2619	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2620	>	Node<K,V> hd = null, tl = null;
2621	>	for (Node<K,V> q = b; q != null; q = q.next) {
2622	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2623	>	if (tl == null)
2624	>	hd = p;
2625	>	else
2626	>	tl.next = p;
2627	>	tl = p;
2628	>	}
2629	>	return hd;
2630	>	}
2631	>
2632	>	/* ---------------- TreeNodes -------------- */
2633	>
2634	>	/**
2635	>	* Nodes for use in TreeBins
2636	>	*/
2637	>	static final class TreeNode<K,V> extends Node<K,V> {
2638	>	TreeNode<K,V> parent;  // red-black tree links
2639	>	TreeNode<K,V> left;
2640	>	TreeNode<K,V> right;
2641	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2642	>	boolean red;
2643	>
2644	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2645	>	TreeNode<K,V> parent) {
2646	>	super(hash, key, val, next);
2647	>	this.parent = parent;
2648	>	}
2649	>
2650	>	Node<K,V> find(int h, Object k) {
2651	>	return findTreeNode(h, k, null);
2652	>	}
2653
2654		/**
2655	<	* Number of updates; used for checking lack of modifications
2656	<	* in bulk-read methods.
2655	>	* Returns the TreeNode (or null if not found) for the given key
2656	>	* starting at given root.
2657		*/
2658	<	transient int modCount;
2658	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2659	>	if (k != null) {
2660	>	TreeNode<K,V> p = this;
2661	>	do {
2662	>	int ph, dir; K pk; TreeNode<K,V> q;
2663	>	TreeNode<K,V> pl = p.left, pr = p.right;
2664	>	if ((ph = p.hash) > h)
2665	>	p = pl;
2666	>	else if (ph < h)
2667	>	p = pr;
2668	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2669	>	return p;
2670	>	else if (pl == null)
2671	>	p = pr;
2672	>	else if (pr == null)
2673	>	p = pl;
2674	>	else if ((kc != null ||
2675	>	(kc = comparableClassFor(k)) != null) &&
2676	>	(dir = compareComparables(kc, k, pk)) != 0)
2677	>	p = (dir < 0) ? pl : pr;
2678	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2679	>	return q;
2680	>	else
2681	>	p = pl;
2682	>	} while (p != null);
2683	>	}
2684	>	return null;
2685	>	}
2686	>	}
2687	>
2688	>	/* ---------------- TreeBins -------------- */
2689	>
2690	>	/**
2691	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2692	>	* keys or values, but instead point to list of TreeNodes and
2693	>	* their root. They also maintain a parasitic read-write lock
2694	>	* forcing writers (who hold bin lock) to wait for readers (who do
2695	>	* not) to complete before tree restructuring operations.
2696	>	*/
2697	>	static final class TreeBin<K,V> extends Node<K,V> {
2698	>	TreeNode<K,V> root;
2699	>	volatile TreeNode<K,V> first;
2700	>	volatile Thread waiter;
2701	>	volatile int lockState;
2702	>	// values for lockState
2703	>	static final int WRITER = 1; // set while holding write lock
2704	>	static final int WAITER = 2; // set when waiting for write lock
2705	>	static final int READER = 4; // increment value for setting read lock
2706
2707		/**
2708	<	* The table is rehashed when its size exceeds this threshold.
2709	<	* (The value of this field is always (int)(capacity *
2710	<	* loadFactor).)
2708	>	* Tie-breaking utility for ordering insertions when equal
2709	>	* hashCodes and non-comparable. We don't require a total
2710	>	* order, just a consistent insertion rule to maintain
2711	>	* equivalence across rebalancings. Tie-breaking further than
2712	>	* necessary simplifies testing a bit.
2713		*/
2714	<	private transient int threshold;
2714	>	static int tieBreakOrder(Object a, Object b) {
2715	>	int d;
2716	>	if (a == null || b == null ||
2717	>	(d = a.getClass().getName().
2718	>	compareTo(b.getClass().getName())) == 0)
2719	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2720	>	-1 : 1);
2721	>	return d;
2722	>	}
2723
2724		/**
2725	<	* The per-segment table
2725	>	* Creates bin with initial set of nodes headed by b.
2726		*/
2727	<	transient HashEntry[] table;
2727	>	TreeBin(TreeNode<K,V> b) {
2728	>	super(TREEBIN, null, null, null);
2729	>	this.first = b;
2730	>	TreeNode<K,V> r = null;
2731	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2732	>	next = (TreeNode<K,V>)x.next;
2733	>	x.left = x.right = null;
2734	>	if (r == null) {
2735	>	x.parent = null;
2736	>	x.red = false;
2737	>	r = x;
2738	>	}
2739	>	else {
2740	>	K k = x.key;
2741	>	int h = x.hash;
2742	>	Class<?> kc = null;
2743	>	for (TreeNode<K,V> p = r;;) {
2744	>	int dir, ph;
2745	>	K pk = p.key;
2746	>	if ((ph = p.hash) > h)
2747	>	dir = -1;
2748	>	else if (ph < h)
2749	>	dir = 1;
2750	>	else if ((kc == null &&
2751	>	(kc = comparableClassFor(k)) == null) ||
2752	>	(dir = compareComparables(kc, k, pk)) == 0)
2753	>	dir = tieBreakOrder(k, pk);
2754	>	TreeNode<K,V> xp = p;
2755	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2756	>	x.parent = xp;
2757	>	if (dir <= 0)
2758	>	xp.left = x;
2759	>	else
2760	>	xp.right = x;
2761	>	r = balanceInsertion(r, x);
2762	>	break;
2763	>	}
2764	>	}
2765	>	}
2766	>	}
2767	>	this.root = r;
2768	>	assert checkInvariants(root);
2769	>	}
2770
2771		/**
2772	<	* The load factor for the hash table.  Even though this value
225	<	* is same for all segments, it is replicated to avoid needing
226	<	* links to outer object.
227	<	* @serial
2772	>	* Acquires write lock for tree restructuring.
2773		*/
2774	<	private final float loadFactor;
2775	<
2776	<	Segment(int initialCapacity, float lf) {
232	<	loadFactor = lf;
233	<	setTable(new HashEntry[initialCapacity]);
2774	>	private final void lockRoot() {
2775	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2776	>	contendedLock(); // offload to separate method
2777		}
2778
2779		/**
2780	<	* Set table to new HashEntry array.
2781	<	* Call only while holding lock or in constructor.
2782	<	**/
2783	<	private void setTable(HashEntry[] newTable) {
241	<	table = newTable;
242	<	threshold = (int)(newTable.length * loadFactor);
243	<	count = count; // write-volatile
2780	>	* Releases write lock for tree restructuring.
2781	>	*/
2782	>	private final void unlockRoot() {
2783	>	lockState = 0;
2784		}
2785
2786	<	/* Specialized implementations of map methods */
2787	<
2788	<	V get(K key, int hash) {
2789	<	if (count != 0) { // read-volatile
2790	<	HashEntry[] tab = table;
2791	<	int index = hash & (tab.length - 1);
2792	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
2793	<	while (e != null) {
2794	<	if (e.hash == hash && key.equals(e.key))
2795	<	return e.value;
2796	<	e = e.next;
2786	>	/**
2787	>	* Possibly blocks awaiting root lock.
2788	>	*/
2789	>	private final void contendedLock() {
2790	>	boolean waiting = false;
2791	>	for (int s;;) {
2792	>	if (((s = lockState) & ~WAITER) == 0) {
2793	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2794	>	if (waiting)
2795	>	waiter = null;
2796	>	return;
2797	>	}
2798		}
2799	+	else if ((s & WAITER) == 0) {
2800	+	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2801	+	waiting = true;
2802	+	waiter = Thread.currentThread();
2803	+	}
2804	+	}
2805	+	else if (waiting)
2806	+	LockSupport.park(this);
2807		}
259	–	return null;
2808		}
2809
2810	<	boolean containsKey(Object key, int hash) {
2811	<	if (count != 0) { // read-volatile
2812	<	HashEntry[] tab = table;
2813	<	int index = hash & (tab.length - 1);
2814	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
2815	<	while (e != null) {
2816	<	if (e.hash == hash && key.equals(e.key))
2817	<	return true;
2818	<	e = e.next;
2810	>	/**
2811	>	* Returns matching node or null if none. Tries to search
2812	>	* using tree comparisons from root, but continues linear
2813	>	* search when lock not available.
2814	>	*/
2815	>	final Node<K,V> find(int h, Object k) {
2816	>	if (k != null) {
2817	>	for (Node<K,V> e = first; e != null; ) {
2818	>	int s; K ek;
2819	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2820	>	if (e.hash == h &&
2821	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2822	>	return e;
2823	>	e = e.next;
2824	>	}
2825	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2826	>	s + READER)) {
2827	>	TreeNode<K,V> r, p;
2828	>	try {
2829	>	p = ((r = root) == null ? null :
2830	>	r.findTreeNode(h, k, null));
2831	>	} finally {
2832	>	Thread w;
2833	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2834	>	(READER|WAITER) && (w = waiter) != null)
2835	>	LockSupport.unpark(w);
2836	>	}
2837	>	return p;
2838	>	}
2839		}
2840		}
2841	<	return false;
2841	>	return null;
2842		}
2843
2844	<	boolean containsValue(Object value) {
2845	<	if (count != 0) { // read-volatile
2846	<	HashEntry[] tab = table;
2847	<	int len = tab.length;
2848	<	for (int i = 0 ; i < len; i++)
2849	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i] ; e != null ; e = e.next)
2850	<	if (value.equals(e.value))
2851	<	return true;
2844	>	/**
2845	>	* Finds or adds a node.
2846	>	* @return null if added
2847	>	*/
2848	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2849	>	Class<?> kc = null;
2850	>	boolean searched = false;
2851	>	for (TreeNode<K,V> p = root;;) {
2852	>	int dir, ph; K pk;
2853	>	if (p == null) {
2854	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2855	>	break;
2856	>	}
2857	>	else if ((ph = p.hash) > h)
2858	>	dir = -1;
2859	>	else if (ph < h)
2860	>	dir = 1;
2861	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2862	>	return p;
2863	>	else if ((kc == null &&
2864	>	(kc = comparableClassFor(k)) == null) ||
2865	>	(dir = compareComparables(kc, k, pk)) == 0) {
2866	>	if (!searched) {
2867	>	TreeNode<K,V> q, ch;
2868	>	searched = true;
2869	>	if (((ch = p.left) != null &&
2870	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2871	>	((ch = p.right) != null &&
2872	>	(q = ch.findTreeNode(h, k, kc)) != null))
2873	>	return q;
2874	>	}
2875	>	dir = tieBreakOrder(k, pk);
2876	>	}
2877	>
2878	>	TreeNode<K,V> xp = p;
2879	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2880	>	TreeNode<K,V> x, f = first;
2881	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2882	>	if (f != null)
2883	>	f.prev = x;
2884	>	if (dir <= 0)
2885	>	xp.left = x;
2886	>	else
2887	>	xp.right = x;
2888	>	if (!xp.red)
2889	>	x.red = true;
2890	>	else {
2891	>	lockRoot();
2892	>	try {
2893	>	root = balanceInsertion(root, x);
2894	>	} finally {
2895	>	unlockRoot();
2896	>	}
2897	>	}
2898	>	break;
2899	>	}
2900		}
2901	<	return false;
2901	>	assert checkInvariants(root);
2902	>	return null;
2903		}
2904
2905	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
2906	<	lock();
2905	>	/**
2906	>	* Removes the given node, that must be present before this
2907	>	* call.  This is messier than typical red-black deletion code
2908	>	* because we cannot swap the contents of an interior node
2909	>	* with a leaf successor that is pinned by "next" pointers
2910	>	* that are accessible independently of lock. So instead we
2911	>	* swap the tree linkages.
2912	>	*
2913	>	* @return true if now too small, so should be untreeified
2914	>	*/
2915	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2916	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2917	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2918	>	TreeNode<K,V> r, rl;
2919	>	if (pred == null)
2920	>	first = next;
2921	>	else
2922	>	pred.next = next;
2923	>	if (next != null)
2924	>	next.prev = pred;
2925	>	if (first == null) {
2926	>	root = null;
2927	>	return true;
2928	>	}
2929	>	if ((r = root) == null || r.right == null || // too small
2930	>	(rl = r.left) == null || rl.left == null)
2931	>	return true;
2932	>	lockRoot();
2933		try {
2934	<	int c = count;
2935	<	HashEntry[] tab = table;
2936	<	int index = hash & (tab.length - 1);
2937	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
2938	<
2939	<	for (HashEntry<K,V> e = first; e != null; e = (HashEntry<K,V>) e.next) {
2940	<	if (e.hash == hash && key.equals(e.key)) {
2941	<	V oldValue = e.value;
2942	<	if (!onlyIfAbsent)
2943	<	e.value = value;
2944	<	++modCount;
2945	<	count = c; // write-volatile
2946	<	return oldValue;
2934	>	TreeNode<K,V> replacement;
2935	>	TreeNode<K,V> pl = p.left;
2936	>	TreeNode<K,V> pr = p.right;
2937	>	if (pl != null && pr != null) {
2938	>	TreeNode<K,V> s = pr, sl;
2939	>	while ((sl = s.left) != null) // find successor
2940	>	s = sl;
2941	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2942	>	TreeNode<K,V> sr = s.right;
2943	>	TreeNode<K,V> pp = p.parent;
2944	>	if (s == pr) { // p was s's direct parent
2945	>	p.parent = s;
2946	>	s.right = p;
2947		}
2948	+	else {
2949	+	TreeNode<K,V> sp = s.parent;
2950	+	if ((p.parent = sp) != null) {
2951	+	if (s == sp.left)
2952	+	sp.left = p;
2953	+	else
2954	+	sp.right = p;
2955	+	}
2956	+	if ((s.right = pr) != null)
2957	+	pr.parent = s;
2958	+	}
2959	+	p.left = null;
2960	+	if ((p.right = sr) != null)
2961	+	sr.parent = p;
2962	+	if ((s.left = pl) != null)
2963	+	pl.parent = s;
2964	+	if ((s.parent = pp) == null)
2965	+	r = s;
2966	+	else if (p == pp.left)
2967	+	pp.left = s;
2968	+	else
2969	+	pp.right = s;
2970	+	if (sr != null)
2971	+	replacement = sr;
2972	+	else
2973	+	replacement = p;
2974	+	}
2975	+	else if (pl != null)
2976	+	replacement = pl;
2977	+	else if (pr != null)
2978	+	replacement = pr;
2979	+	else
2980	+	replacement = p;
2981	+	if (replacement != p) {
2982	+	TreeNode<K,V> pp = replacement.parent = p.parent;
2983	+	if (pp == null)
2984	+	r = replacement;
2985	+	else if (p == pp.left)
2986	+	pp.left = replacement;
2987	+	else
2988	+	pp.right = replacement;
2989	+	p.left = p.right = p.parent = null;
2990		}
2991
2992	<	tab[index] = new HashEntry<K,V>(hash, key, value, first);
2993	<	++modCount;
2994	<	++c;
2995	<	count = c; // write-volatile
2996	<	if (c > threshold)
2997	<	setTable(rehash(tab));
2998	<	return null;
2992	>	root = (p.red) ? r : balanceDeletion(r, replacement);
2993	>
2994	>	if (p == replacement) {  // detach pointers
2995	>	TreeNode<K,V> pp;
2996	>	if ((pp = p.parent) != null) {
2997	>	if (p == pp.left)
2998	>	pp.left = null;
2999	>	else if (p == pp.right)
3000	>	pp.right = null;
3001	>	p.parent = null;
3002	>	}
3003	>	}
3004		} finally {
3005	<	unlock();
3005	>	unlockRoot();
3006		}
3007	+	assert checkInvariants(root);
3008	+	return false;
3009		}
3010
3011	<	private HashEntry[] rehash(HashEntry[] oldTable) {
3012	<	int oldCapacity = oldTable.length;
321	<	if (oldCapacity >= MAXIMUM_CAPACITY)
322	<	return oldTable;
323	<
324	<	/*
325	<	* Reclassify nodes in each list to new Map.  Because we are
326	<	* using power-of-two expansion, the elements from each bin
327	<	* must either stay at same index, or move with a power of two
328	<	* offset. We eliminate unnecessary node creation by catching
329	<	* cases where old nodes can be reused because their next
330	<	* fields won't change. Statistically, at the default
331	<	* threshhold, only about one-sixth of them need cloning when
332	<	* a table doubles. The nodes they replace will be garbage
333	<	* collectable as soon as they are no longer referenced by any
334	<	* reader thread that may be in the midst of traversing table
335	<	* right now.
336	<	*/
337	<
338	<	HashEntry[] newTable = new HashEntry[oldCapacity << 1];
339	<	int sizeMask = newTable.length - 1;
340	<	for (int i = 0; i < oldCapacity ; i++) {
341	<	// We need to guarantee that any existing reads of old Map can
342	<	//  proceed. So we cannot yet null out each bin.
343	<	HashEntry<K,V> e = (HashEntry<K,V>)oldTable[i];
344	<
345	<	if (e != null) {
346	<	HashEntry<K,V> next = e.next;
347	<	int idx = e.hash & sizeMask;
348	<
349	<	//  Single node on list
350	<	if (next == null)
351	<	newTable[idx] = e;
3011	>	/* ------------------------------------------------------------ */
3012	>	// Red-black tree methods, all adapted from CLR
3013
3014	+	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3015	+	TreeNode<K,V> p) {
3016	+	TreeNode<K,V> r, pp, rl;
3017	+	if (p != null && (r = p.right) != null) {
3018	+	if ((rl = p.right = r.left) != null)
3019	+	rl.parent = p;
3020	+	if ((pp = r.parent = p.parent) == null)
3021	+	(root = r).red = false;
3022	+	else if (pp.left == p)
3023	+	pp.left = r;
3024	+	else
3025	+	pp.right = r;
3026	+	r.left = p;
3027	+	p.parent = r;
3028	+	}
3029	+	return root;
3030	+	}
3031	+
3032	+	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3033	+	TreeNode<K,V> p) {
3034	+	TreeNode<K,V> l, pp, lr;
3035	+	if (p != null && (l = p.left) != null) {
3036	+	if ((lr = p.left = l.right) != null)
3037	+	lr.parent = p;
3038	+	if ((pp = l.parent = p.parent) == null)
3039	+	(root = l).red = false;
3040	+	else if (pp.right == p)
3041	+	pp.right = l;
3042	+	else
3043	+	pp.left = l;
3044	+	l.right = p;
3045	+	p.parent = l;
3046	+	}
3047	+	return root;
3048	+	}
3049	+
3050	+	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3051	+	TreeNode<K,V> x) {
3052	+	x.red = true;
3053	+	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3054	+	if ((xp = x.parent) == null) {
3055	+	x.red = false;
3056	+	return x;
3057	+	}
3058	+	else if (!xp.red || (xpp = xp.parent) == null)
3059	+	return root;
3060	+	if (xp == (xppl = xpp.left)) {
3061	+	if ((xppr = xpp.right) != null && xppr.red) {
3062	+	xppr.red = false;
3063	+	xp.red = false;
3064	+	xpp.red = true;
3065	+	x = xpp;
3066	+	}
3067	+	else {
3068	+	if (x == xp.right) {
3069	+	root = rotateLeft(root, x = xp);
3070	+	xpp = (xp = x.parent) == null ? null : xp.parent;
3071	+	}
3072	+	if (xp != null) {
3073	+	xp.red = false;
3074	+	if (xpp != null) {
3075	+	xpp.red = true;
3076	+	root = rotateRight(root, xpp);
3077	+	}
3078	+	}
3079	+	}
3080	+	}
3081	+	else {
3082	+	if (xppl != null && xppl.red) {
3083	+	xppl.red = false;
3084	+	xp.red = false;
3085	+	xpp.red = true;
3086	+	x = xpp;
3087	+	}
3088		else {
3089	<	// Reuse trailing consecutive sequence at same slot
3090	<	HashEntry<K,V> lastRun = e;
3091	<	int lastIdx = idx;
3092	<	for (HashEntry<K,V> last = next;
3093	<	last != null;
3094	<	last = last.next) {
3095	<	int k = last.hash & sizeMask;
3096	<	if (k != lastIdx) {
3097	<	lastIdx = k;
363	<	lastRun = last;
3089	>	if (x == xp.left) {
3090	>	root = rotateRight(root, x = xp);
3091	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3092	>	}
3093	>	if (xp != null) {
3094	>	xp.red = false;
3095	>	if (xpp != null) {
3096	>	xpp.red = true;
3097	>	root = rotateLeft(root, xpp);
3098		}
3099		}
3100	<	newTable[lastIdx] = lastRun;
3100	>	}
3101	>	}
3102	>	}
3103	>	}
3104
3105	<	// Clone all remaining nodes
3106	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
3107	<	int k = p.hash & sizeMask;
3108	<	newTable[k] = new HashEntry<K,V>(p.hash,
3109	<	p.key,
3110	<	p.value,
3111	<	(HashEntry<K,V>) newTable[k]);
3105	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3106	>	TreeNode<K,V> x) {
3107	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3108	>	if (x == null || x == root)
3109	>	return root;
3110	>	else if ((xp = x.parent) == null) {
3111	>	x.red = false;
3112	>	return x;
3113	>	}
3114	>	else if (x.red) {
3115	>	x.red = false;
3116	>	return root;
3117	>	}
3118	>	else if ((xpl = xp.left) == x) {
3119	>	if ((xpr = xp.right) != null && xpr.red) {
3120	>	xpr.red = false;
3121	>	xp.red = true;
3122	>	root = rotateLeft(root, xp);
3123	>	xpr = (xp = x.parent) == null ? null : xp.right;
3124	>	}
3125	>	if (xpr == null)
3126	>	x = xp;
3127	>	else {
3128	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3129	>	if ((sr == null || !sr.red) &&
3130	>	(sl == null || !sl.red)) {
3131	>	xpr.red = true;
3132	>	x = xp;
3133	>	}
3134	>	else {
3135	>	if (sr == null || !sr.red) {
3136	>	if (sl != null)
3137	>	sl.red = false;
3138	>	xpr.red = true;
3139	>	root = rotateRight(root, xpr);
3140	>	xpr = (xp = x.parent) == null ?
3141	>	null : xp.right;
3142	>	}
3143	>	if (xpr != null) {
3144	>	xpr.red = (xp == null) ? false : xp.red;
3145	>	if ((sr = xpr.right) != null)
3146	>	sr.red = false;
3147	>	}
3148	>	if (xp != null) {
3149	>	xp.red = false;
3150	>	root = rotateLeft(root, xp);
3151	>	}
3152	>	x = root;
3153	>	}
3154	>	}
3155	>	}
3156	>	else { // symmetric
3157	>	if (xpl != null && xpl.red) {
3158	>	xpl.red = false;
3159	>	xp.red = true;
3160	>	root = rotateRight(root, xp);
3161	>	xpl = (xp = x.parent) == null ? null : xp.left;
3162	>	}
3163	>	if (xpl == null)
3164	>	x = xp;
3165	>	else {
3166	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3167	>	if ((sl == null || !sl.red) &&
3168	>	(sr == null || !sr.red)) {
3169	>	xpl.red = true;
3170	>	x = xp;
3171	>	}
3172	>	else {
3173	>	if (sl == null || !sl.red) {
3174	>	if (sr != null)
3175	>	sr.red = false;
3176	>	xpl.red = true;
3177	>	root = rotateLeft(root, xpl);
3178	>	xpl = (xp = x.parent) == null ?
3179	>	null : xp.left;
3180	>	}
3181	>	if (xpl != null) {
3182	>	xpl.red = (xp == null) ? false : xp.red;
3183	>	if ((sl = xpl.left) != null)
3184	>	sl.red = false;
3185	>	}
3186	>	if (xp != null) {
3187	>	xp.red = false;
3188	>	root = rotateRight(root, xp);
3189	>	}
3190	>	x = root;
3191		}
3192		}
3193		}
3194		}
379	–	return newTable;
3195		}
3196
3197		/**
3198	<	* Remove; match on key only if value null, else match both.
3198	>	* Recursive invariant check
3199		*/
3200	<	V remove(Object key, int hash, Object value) {
3201	<	lock();
3200	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3201	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3202	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3203	>	if (tb != null && tb.next != t)
3204	>	return false;
3205	>	if (tn != null && tn.prev != t)
3206	>	return false;
3207	>	if (tp != null && t != tp.left && t != tp.right)
3208	>	return false;
3209	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3210	>	return false;
3211	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3212	>	return false;
3213	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3214	>	return false;
3215	>	if (tl != null && !checkInvariants(tl))
3216	>	return false;
3217	>	if (tr != null && !checkInvariants(tr))
3218	>	return false;
3219	>	return true;
3220	>	}
3221	>
3222	>	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
3223	>	private static final long LOCKSTATE;
3224	>	static {
3225		try {
3226	<	int c = count;
3227	<	HashEntry[] tab = table;
3228	<	int index = hash & (tab.length - 1);
3229	<	HashEntry<K,V> first = (HashEntry<K,V>)tab[index];
3226	>	LOCKSTATE = U.objectFieldOffset
3227	>	(TreeBin.class.getDeclaredField("lockState"));
3228	>	} catch (ReflectiveOperationException e) {
3229	>	throw new Error(e);
3230	>	}
3231	>	}
3232	>	}
3233
3234	<	HashEntry<K,V> e = first;
394	<	for (;;) {
395	<	if (e == null)
396	<	return null;
397	<	if (e.hash == hash && key.equals(e.key))
398	<	break;
399	<	e = e.next;
400	<	}
3234	>	/* ----------------Table Traversal -------------- */
3235
3236	<	V oldValue = e.value;
3237	<	if (value != null && !value.equals(oldValue))
3238	<	return null;
3236	>	/**
3237	>	* Records the table, its length, and current traversal index for a
3238	>	* traverser that must process a region of a forwarded table before
3239	>	* proceeding with current table.
3240	>	*/
3241	>	static final class TableStack<K,V> {
3242	>	int length;
3243	>	int index;
3244	>	Node<K,V>[] tab;
3245	>	TableStack<K,V> next;
3246	>	}
3247
3248	<	// All entries following removed node can stay in list, but
3249	<	// all preceeding ones need to be cloned.
3250	<	HashEntry<K,V> newFirst = e.next;
3251	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
3252	<	newFirst = new HashEntry<K,V>(p.hash, p.key,
3253	<	p.value, newFirst);
3254	<	tab[index] = newFirst;
3255	<	++modCount;
3256	<	count = c-1; // write-volatile
3257	<	return oldValue;
3258	<	} finally {
3259	<	unlock();
3248	>	/**
3249	>	* Encapsulates traversal for methods such as containsValue; also
3250	>	* serves as a base class for other iterators and spliterators.
3251	>	*
3252	>	* Method advance visits once each still-valid node that was
3253	>	* reachable upon iterator construction. It might miss some that
3254	>	* were added to a bin after the bin was visited, which is OK wrt
3255	>	* consistency guarantees. Maintaining this property in the face
3256	>	* of possible ongoing resizes requires a fair amount of
3257	>	* bookkeeping state that is difficult to optimize away amidst
3258	>	* volatile accesses.  Even so, traversal maintains reasonable
3259	>	* throughput.
3260	>	*
3261	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3262	>	* However, if the table has been resized, then all future steps
3263	>	* must traverse both the bin at the current index as well as at
3264	>	* (index + baseSize); and so on for further resizings. To
3265	>	* paranoically cope with potential sharing by users of iterators
3266	>	* across threads, iteration terminates if a bounds checks fails
3267	>	* for a table read.
3268	>	*/
3269	>	static class Traverser<K,V> {
3270	>	Node<K,V>[] tab;        // current table; updated if resized
3271	>	Node<K,V> next;         // the next entry to use
3272	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3273	>	int index;              // index of bin to use next
3274	>	int baseIndex;          // current index of initial table
3275	>	int baseLimit;          // index bound for initial table
3276	>	final int baseSize;     // initial table size
3277	>
3278	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3279	>	this.tab = tab;
3280	>	this.baseSize = size;
3281	>	this.baseIndex = this.index = index;
3282	>	this.baseLimit = limit;
3283	>	this.next = null;
3284	>	}
3285	>
3286	>	/**
3287	>	* Advances if possible, returning next valid node, or null if none.
3288	>	*/
3289	>	final Node<K,V> advance() {
3290	>	Node<K,V> e;
3291	>	if ((e = next) != null)
3292	>	e = e.next;
3293	>	for (;;) {
3294	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3295	>	if (e != null)
3296	>	return next = e;
3297	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3298	>	(n = t.length) <= (i = index) || i < 0)
3299	>	return next = null;
3300	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3301	>	if (e instanceof ForwardingNode) {
3302	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3303	>	e = null;
3304	>	pushState(t, i, n);
3305	>	continue;
3306	>	}
3307	>	else if (e instanceof TreeBin)
3308	>	e = ((TreeBin<K,V>)e).first;
3309	>	else
3310	>	e = null;
3311	>	}
3312	>	if (stack != null)
3313	>	recoverState(n);
3314	>	else if ((index = i + baseSize) >= n)
3315	>	index = ++baseIndex; // visit upper slots if present
3316		}
3317		}
3318
3319	<	void clear() {
3320	<	lock();
3321	<	try {
3322	<	HashEntry[] tab = table;
3323	<	for (int i = 0; i < tab.length ; i++)
3324	<	tab[i] = null;
3325	<	++modCount;
3326	<	count = 0; // write-volatile
3327	<	} finally {
3328	<	unlock();
3319	>	/**
3320	>	* Saves traversal state upon encountering a forwarding node.
3321	>	*/
3322	>	private void pushState(Node<K,V>[] t, int i, int n) {
3323	>	TableStack<K,V> s = spare;  // reuse if possible
3324	>	if (s != null)
3325	>	spare = s.next;
3326	>	else
3327	>	s = new TableStack<K,V>();
3328	>	s.tab = t;
3329	>	s.length = n;
3330	>	s.index = i;
3331	>	s.next = stack;
3332	>	stack = s;
3333	>	}
3334	>
3335	>	/**
3336	>	* Possibly pops traversal state.
3337	>	*
3338	>	* @param n length of current table
3339	>	*/
3340	>	private void recoverState(int n) {
3341	>	TableStack<K,V> s; int len;
3342	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3343	>	n = len;
3344	>	index = s.index;
3345	>	tab = s.tab;
3346	>	s.tab = null;
3347	>	TableStack<K,V> next = s.next;
3348	>	s.next = spare; // save for reuse
3349	>	stack = next;
3350	>	spare = s;
3351		}
3352	+	if (s == null && (index += baseSize) >= n)
3353	+	index = ++baseIndex;
3354		}
3355		}
3356
3357		/**
3358	<	* ConcurrentHashMap list entry.
3358	>	* Base of key, value, and entry Iterators. Adds fields to
3359	>	* Traverser to support iterator.remove.
3360		*/
3361	<	private static class HashEntry<K,V> implements Entry<K,V> {
3362	<	private final K key;
3363	<	private V value;
3364	<	private final int hash;
3365	<	private final HashEntry<K,V> next;
3361	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3362	>	final ConcurrentHashMap<K,V> map;
3363	>	Node<K,V> lastReturned;
3364	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3365	>	ConcurrentHashMap<K,V> map) {
3366	>	super(tab, size, index, limit);
3367	>	this.map = map;
3368	>	advance();
3369	>	}
3370
3371	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
3372	<	this.value = value;
3373	<	this.hash = hash;
3374	<	this.key = key;
3375	<	this.next = next;
3371	>	public final boolean hasNext() { return next != null; }
3372	>	public final boolean hasMoreElements() { return next != null; }
3373	>
3374	>	public final void remove() {
3375	>	Node<K,V> p;
3376	>	if ((p = lastReturned) == null)
3377	>	throw new IllegalStateException();
3378	>	lastReturned = null;
3379	>	map.replaceNode(p.key, null, null);
3380	>	}
3381	>	}
3382	>
3383	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3384	>	implements Iterator<K>, Enumeration<K> {
3385	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3386	>	ConcurrentHashMap<K,V> map) {
3387	>	super(tab, index, size, limit, map);
3388	>	}
3389	>
3390	>	public final K next() {
3391	>	Node<K,V> p;
3392	>	if ((p = next) == null)
3393	>	throw new NoSuchElementException();
3394	>	K k = p.key;
3395	>	lastReturned = p;
3396	>	advance();
3397	>	return k;
3398	>	}
3399	>
3400	>	public final K nextElement() { return next(); }
3401	>	}
3402	>
3403	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3404	>	implements Iterator<V>, Enumeration<V> {
3405	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3406	>	ConcurrentHashMap<K,V> map) {
3407	>	super(tab, index, size, limit, map);
3408	>	}
3409	>
3410	>	public final V next() {
3411	>	Node<K,V> p;
3412	>	if ((p = next) == null)
3413	>	throw new NoSuchElementException();
3414	>	V v = p.val;
3415	>	lastReturned = p;
3416	>	advance();
3417	>	return v;
3418		}
3419
3420	<	public K getKey() {
3421	<	return key;
3420	>	public final V nextElement() { return next(); }
3421	>	}
3422	>
3423	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3424	>	implements Iterator<Map.Entry<K,V>> {
3425	>	EntryIterator(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 V getValue() {
3431	<	return value;
3430	>	public final Map.Entry<K,V> next() {
3431	>	Node<K,V> p;
3432	>	if ((p = next) == null)
3433	>	throw new NoSuchElementException();
3434	>	K k = p.key;
3435	>	V v = p.val;
3436	>	lastReturned = p;
3437	>	advance();
3438	>	return new MapEntry<K,V>(k, v, map);
3439		}
3440	+	}
3441
3442	<	public V setValue(V newValue) {
3443	<	// We aren't required to, and don't provide any
3444	<	// visibility barriers for setting value.
3445	<	if (newValue == null)
3446	<	throw new NullPointerException();
3447	<	V oldValue = this.value;
3448	<	this.value = newValue;
3449	<	return oldValue;
3442	>	/**
3443	>	* Exported Entry for EntryIterator
3444	>	*/
3445	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3446	>	final K key; // non-null
3447	>	V val;       // non-null
3448	>	final ConcurrentHashMap<K,V> map;
3449	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3450	>	this.key = key;
3451	>	this.val = val;
3452	>	this.map = map;
3453		}
3454	+	public K getKey()        { return key; }
3455	+	public V getValue()      { return val; }
3456	+	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3457	+	public String toString() { return key + "=" + val; }
3458
3459		public boolean equals(Object o) {
3460	<	if (!(o instanceof Entry))
3461	<	return false;
3462	<	Entry<K,V> e = (Entry<K,V>)o;
3463	<	return (key.equals(e.getKey()) && value.equals(e.getValue()));
3460	>	Object k, v; Map.Entry<?,?> e;
3461	>	return ((o instanceof Map.Entry) &&
3462	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3463	>	(v = e.getValue()) != null &&
3464	>	(k == key || k.equals(key)) &&
3465	>	(v == val || v.equals(val)));
3466		}
3467
3468	<	public int hashCode() {
3469	<	return  key.hashCode() ^ value.hashCode();
3468	>	/**
3469	>	* Sets our entry's value and writes through to the map. The
3470	>	* value to return is somewhat arbitrary here. Since we do not
3471	>	* necessarily track asynchronous changes, the most recent
3472	>	* "previous" value could be different from what we return (or
3473	>	* could even have been removed, in which case the put will
3474	>	* re-establish). We do not and cannot guarantee more.
3475	>	*/
3476	>	public V setValue(V value) {
3477	>	if (value == null) throw new NullPointerException();
3478	>	V v = val;
3479	>	val = value;
3480	>	map.put(key, value);
3481	>	return v;
3482	>	}
3483	>	}
3484	>
3485	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3486	>	implements Spliterator<K> {
3487	>	long est;               // size estimate
3488	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3489	>	long est) {
3490	>	super(tab, size, index, limit);
3491	>	this.est = est;
3492	>	}
3493	>
3494	>	public Spliterator<K> trySplit() {
3495	>	int i, f, h;
3496	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3497	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3498	>	f, est >>>= 1);
3499	>	}
3500	>
3501	>	public void forEachRemaining(Consumer<? super K> action) {
3502	>	if (action == null) throw new NullPointerException();
3503	>	for (Node<K,V> p; (p = advance()) != null;)
3504	>	action.accept(p.key);
3505	>	}
3506	>
3507	>	public boolean tryAdvance(Consumer<? super K> action) {
3508	>	if (action == null) throw new NullPointerException();
3509	>	Node<K,V> p;
3510	>	if ((p = advance()) == null)
3511	>	return false;
3512	>	action.accept(p.key);
3513	>	return true;
3514		}
3515
3516	<	public String toString() {
3517	<	return key + "=" + value;
3516	>	public long estimateSize() { return est; }
3517	>
3518	>	public int characteristics() {
3519	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3520	>	Spliterator.NONNULL;
3521		}
3522		}
3523
3524	+	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3525	+	implements Spliterator<V> {
3526	+	long est;               // size estimate
3527	+	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3528	+	long est) {
3529	+	super(tab, size, index, limit);
3530	+	this.est = est;
3531	+	}
3532	+
3533	+	public Spliterator<V> trySplit() {
3534	+	int i, f, h;
3535	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3536	+	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3537	+	f, est >>>= 1);
3538	+	}
3539	+
3540	+	public void forEachRemaining(Consumer<? super V> action) {
3541	+	if (action == null) throw new NullPointerException();
3542	+	for (Node<K,V> p; (p = advance()) != null;)
3543	+	action.accept(p.val);
3544	+	}
3545	+
3546	+	public boolean tryAdvance(Consumer<? super V> action) {
3547	+	if (action == null) throw new NullPointerException();
3548	+	Node<K,V> p;
3549	+	if ((p = advance()) == null)
3550	+	return false;
3551	+	action.accept(p.val);
3552	+	return true;
3553	+	}
3554
3555	<	/* ---------------- Public operations -------------- */
3555	>	public long estimateSize() { return est; }
3556
3557	<	/**
3558	<	* Constructs a new, empty map with the specified initial
3559	<	* capacity and the specified load factor.
3560	<	*
492	<	* @param initialCapacity the initial capacity. The implementation
493	<	* performs internal sizing to accommodate this many elements.
494	<	* @param loadFactor  the load factor threshold, used to control resizing.
495	<	* @param concurrencyLevel the estimated number of concurrently
496	<	* updating threads. The implementation performs internal sizing
497	<	* to try to accommodate this many threads.
498	<	* @throws IllegalArgumentException if the initial capacity is
499	<	* negative or the load factor or concurrencyLevel are
500	<	* nonpositive.
501	<	*/
502	<	public ConcurrentHashMap(int initialCapacity,
503	<	float loadFactor, int concurrencyLevel) {
504	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
505	<	throw new IllegalArgumentException();
3557	>	public int characteristics() {
3558	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3559	>	}
3560	>	}
3561
3562	<	if (concurrencyLevel > MAX_SEGMENTS)
3563	<	concurrencyLevel = MAX_SEGMENTS;
3562	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3563	>	implements Spliterator<Map.Entry<K,V>> {
3564	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3565	>	long est;               // size estimate
3566	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3567	>	long est, ConcurrentHashMap<K,V> map) {
3568	>	super(tab, size, index, limit);
3569	>	this.map = map;
3570	>	this.est = est;
3571	>	}
3572	>
3573	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3574	>	int i, f, h;
3575	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3576	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3577	>	f, est >>>= 1, map);
3578	>	}
3579	>
3580	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3581	>	if (action == null) throw new NullPointerException();
3582	>	for (Node<K,V> p; (p = advance()) != null; )
3583	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3584	>	}
3585	>
3586	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3587	>	if (action == null) throw new NullPointerException();
3588	>	Node<K,V> p;
3589	>	if ((p = advance()) == null)
3590	>	return false;
3591	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3592	>	return true;
3593	>	}
3594
3595	<	// Find power-of-two sizes best matching arguments
3596	<	int sshift = 0;
3597	<	int ssize = 1;
3598	<	while (ssize < concurrencyLevel) {
3599	<	++sshift;
515	<	ssize <<= 1;
3595	>	public long estimateSize() { return est; }
3596	>
3597	>	public int characteristics() {
3598	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3599	>	Spliterator.NONNULL;
3600		}
3601	<	segmentShift = 32 - sshift;
3602	<	segmentMask = ssize - 1;
3603	<	this.segments = new Segment[ssize];
520	<
521	<	if (initialCapacity > MAXIMUM_CAPACITY)
522	<	initialCapacity = MAXIMUM_CAPACITY;
523	<	int c = initialCapacity / ssize;
524	<	if (c * ssize < initialCapacity)
525	<	++c;
526	<	int cap = 1;
527	<	while (cap < c)
528	<	cap <<= 1;
3601	>	}
3602	>
3603	>	// Parallel bulk operations
3604
3605	<	for (int i = 0; i < this.segments.length; ++i)
3606	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
3605	>	/**
3606	>	* Computes initial batch value for bulk tasks. The returned value
3607	>	* is approximately exp2 of the number of times (minus one) to
3608	>	* split task by two before executing leaf action. This value is
3609	>	* faster to compute and more convenient to use as a guide to
3610	>	* splitting than is the depth, since it is used while dividing by
3611	>	* two anyway.
3612	>	*/
3613	>	final int batchFor(long b) {
3614	>	long n;
3615	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3616	>	return 0;
3617	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3618	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3619		}
3620
3621		/**
3622	<	* Constructs a new, empty map with the specified initial
536	<	* capacity,  and with default load factor and concurrencyLevel.
3622	>	* Performs the given action for each (key, value).
3623		*
3624	<	* @param initialCapacity The implementation performs internal
3625	<	* sizing to accommodate this many elements.
3626	<	* @throws IllegalArgumentException if the initial capacity of
3627	<	* elements is negative.
3624	>	* @param parallelismThreshold the (estimated) number of elements
3625	>	* needed for this operation to be executed in parallel
3626	>	* @param action the action
3627	>	* @since 1.8
3628		*/
3629	<	public ConcurrentHashMap(int initialCapacity) {
3630	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3629	>	public void forEach(long parallelismThreshold,
3630	>	BiConsumer<? super K,? super V> action) {
3631	>	if (action == null) throw new NullPointerException();
3632	>	new ForEachMappingTask<K,V>
3633	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3634	>	action).invoke();
3635		}
3636
3637		/**
3638	<	* Constructs a new, empty map with a default initial capacity,
3639	<	* load factor, and concurrencyLevel.
3638	>	* Performs the given action for each non-null transformation
3639	>	* of each (key, value).
3640	>	*
3641	>	* @param parallelismThreshold the (estimated) number of elements
3642	>	* needed for this operation to be executed in parallel
3643	>	* @param transformer a function returning the transformation
3644	>	* for an element, or null if there is no transformation (in
3645	>	* which case the action is not applied)
3646	>	* @param action the action
3647	>	* @param <U> the return type of the transformer
3648	>	* @since 1.8
3649		*/
3650	<	public ConcurrentHashMap() {
3651	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3650	>	public <U> void forEach(long parallelismThreshold,
3651	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3652	>	Consumer<? super U> action) {
3653	>	if (transformer == null || action == null)
3654	>	throw new NullPointerException();
3655	>	new ForEachTransformedMappingTask<K,V,U>
3656	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3657	>	transformer, action).invoke();
3658		}
3659
3660		/**
3661	<	* Constructs a new map with the same mappings as the given map.  The
3662	<	* map is created with a capacity of twice the number of mappings in
3663	<	* the given map or 11 (whichever is greater), and a default load factor.
3661	>	* Returns a non-null result from applying the given search
3662	>	* function on each (key, value), or null if none.  Upon
3663	>	* success, further element processing is suppressed and the
3664	>	* results of any other parallel invocations of the search
3665	>	* function are ignored.
3666	>	*
3667	>	* @param parallelismThreshold the (estimated) number of elements
3668	>	* needed for this operation to be executed in parallel
3669	>	* @param searchFunction a function returning a non-null
3670	>	* result on success, else null
3671	>	* @param <U> the return type of the search function
3672	>	* @return a non-null result from applying the given search
3673	>	* function on each (key, value), or null if none
3674	>	* @since 1.8
3675		*/
3676	<	public <A extends K, B extends V> ConcurrentHashMap(Map<A,B> t) {
3677	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
3678	<	11),
3679	<	DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3680	<	putAll(t);
3676	>	public <U> U search(long parallelismThreshold,
3677	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3678	>	if (searchFunction == null) throw new NullPointerException();
3679	>	return new SearchMappingsTask<K,V,U>
3680	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3681	>	searchFunction, new AtomicReference<U>()).invoke();
3682		}
3683
3684	<	// inherit Map javadoc
3685	<	public boolean isEmpty() {
3686	<	/*
3687	<	* We need to keep track of per-segment modCounts to avoid ABA
3688	<	* problems in which an element in one segment was added and
3689	<	* in another removed during traversal, in which case the
3690	<	* table was never actually empty at any point. Note the
3691	<	* similar use of modCounts in the size() and containsValue()
3692	<	* methods, which are the only other methods also susceptible
3693	<	* to ABA problems.
3694	<	*/
3695	<	int[] mc = new int[segments.length];
3696	<	int mcsum = 0;
3697	<	for (int i = 0; i < segments.length; ++i) {
3698	<	if (segments[i].count != 0)
3699	<	return false;
3700	<	else
3701	<	mcsum += mc[i] = segments[i].modCount;
3702	<	}
3703	<	// If mcsum happens to be zero, then we know we got a snapshot
3704	<	// before any modifications at all were made.  This is
3705	<	// probably common enough to bother tracking.
3706	<	if (mcsum != 0) {
3707	<	for (int i = 0; i < segments.length; ++i) {
591	<	if (segments[i].count != 0 ||
592	<	mc[i] != segments[i].modCount)
593	<	return false;
594	<	}
595	<	}
596	<	return true;
3684	>	/**
3685	>	* Returns the result of accumulating the given transformation
3686	>	* of all (key, value) pairs using the given reducer to
3687	>	* combine values, or null if none.
3688	>	*
3689	>	* @param parallelismThreshold the (estimated) number of elements
3690	>	* needed for this operation to be executed in parallel
3691	>	* @param transformer a function returning the transformation
3692	>	* for an element, or null if there is no transformation (in
3693	>	* which case it is not combined)
3694	>	* @param reducer a commutative associative combining function
3695	>	* @param <U> the return type of the transformer
3696	>	* @return the result of accumulating the given transformation
3697	>	* of all (key, value) pairs
3698	>	* @since 1.8
3699	>	*/
3700	>	public <U> U reduce(long parallelismThreshold,
3701	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3702	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3703	>	if (transformer == null || reducer == null)
3704	>	throw new NullPointerException();
3705	>	return new MapReduceMappingsTask<K,V,U>
3706	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3707	>	null, transformer, reducer).invoke();
3708		}
3709
3710	<	// inherit Map javadoc
3711	<	public int size() {
3712	<	int[] mc = new int[segments.length];
3713	<	for (;;) {
3714	<	long sum = 0;
3715	<	int mcsum = 0;
3716	<	for (int i = 0; i < segments.length; ++i) {
3717	<	sum += segments[i].count;
3718	<	mcsum += mc[i] = segments[i].modCount;
3719	<	}
3720	<	int check = 0;
3721	<	if (mcsum != 0) {
3722	<	for (int i = 0; i < segments.length; ++i) {
3723	<	check += segments[i].count;
3724	<	if (mc[i] != segments[i].modCount) {
3725	<	check = -1; // force retry
3726	<	break;
3727	<	}
3728	<	}
3729	<	}
3730	<	if (check == sum) {
3731	<	if (sum > Integer.MAX_VALUE)
3732	<	return Integer.MAX_VALUE;
3733	<	else
623	<	return (int)sum;
624	<	}
625	<	}
3710	>	/**
3711	>	* Returns the result of accumulating the given transformation
3712	>	* of all (key, value) pairs using the given reducer to
3713	>	* combine values, and the given basis as an identity value.
3714	>	*
3715	>	* @param parallelismThreshold the (estimated) number of elements
3716	>	* needed for this operation to be executed in parallel
3717	>	* @param transformer a function returning the transformation
3718	>	* for an element
3719	>	* @param basis the identity (initial default value) for the reduction
3720	>	* @param reducer a commutative associative combining function
3721	>	* @return the result of accumulating the given transformation
3722	>	* of all (key, value) pairs
3723	>	* @since 1.8
3724	>	*/
3725	>	public double reduceToDouble(long parallelismThreshold,
3726	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3727	>	double basis,
3728	>	DoubleBinaryOperator reducer) {
3729	>	if (transformer == null || reducer == null)
3730	>	throw new NullPointerException();
3731	>	return new MapReduceMappingsToDoubleTask<K,V>
3732	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3733	>	null, transformer, basis, reducer).invoke();
3734		}
3735
3736	+	/**
3737	+	* Returns the result of accumulating the given transformation
3738	+	* of all (key, value) pairs using the given reducer to
3739	+	* combine values, and the given basis as an identity value.
3740	+	*
3741	+	* @param parallelismThreshold the (estimated) number of elements
3742	+	* needed for this operation to be executed in parallel
3743	+	* @param transformer a function returning the transformation
3744	+	* for an element
3745	+	* @param basis the identity (initial default value) for the reduction
3746	+	* @param reducer a commutative associative combining function
3747	+	* @return the result of accumulating the given transformation
3748	+	* of all (key, value) pairs
3749	+	* @since 1.8
3750	+	*/
3751	+	public long reduceToLong(long parallelismThreshold,
3752	+	ToLongBiFunction<? super K, ? super V> transformer,
3753	+	long basis,
3754	+	LongBinaryOperator reducer) {
3755	+	if (transformer == null || reducer == null)
3756	+	throw new NullPointerException();
3757	+	return new MapReduceMappingsToLongTask<K,V>
3758	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3759	+	null, transformer, basis, reducer).invoke();
3760	+	}
3761
3762		/**
3763	<	* Returns the value to which the specified key is mapped in this table.
3763	>	* Returns the result of accumulating the given transformation
3764	>	* of all (key, value) pairs using the given reducer to
3765	>	* combine values, and the given basis as an identity value.
3766		*
3767	<	* @param   key   a key in the table.
3768	<	* @return  the value to which the key is mapped in this table;
3769	<	*          <tt>null</tt> if the key is not mapped to any value in
3770	<	*          this table.
3771	<	* @throws  NullPointerException  if the key is
3772	<	*               <tt>null</tt>.
3767	>	* @param parallelismThreshold the (estimated) number of elements
3768	>	* needed for this operation to be executed in parallel
3769	>	* @param transformer a function returning the transformation
3770	>	* for an element
3771	>	* @param basis the identity (initial default value) for the reduction
3772	>	* @param reducer a commutative associative combining function
3773	>	* @return the result of accumulating the given transformation
3774	>	* of all (key, value) pairs
3775	>	* @since 1.8
3776		*/
3777	<	public V get(Object key) {
3778	<	int hash = hash(key); // throws NullPointerException if key null
3779	<	return segmentFor(hash).get((K) key, hash);
3777	>	public int reduceToInt(long parallelismThreshold,
3778	>	ToIntBiFunction<? super K, ? super V> transformer,
3779	>	int basis,
3780	>	IntBinaryOperator reducer) {
3781	>	if (transformer == null || reducer == null)
3782	>	throw new NullPointerException();
3783	>	return new MapReduceMappingsToIntTask<K,V>
3784	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3785	>	null, transformer, basis, reducer).invoke();
3786		}
3787
3788		/**
3789	<	* Tests if the specified object is a key in this table.
3789	>	* Performs the given action for each key.
3790		*
3791	<	* @param   key   possible key.
3792	<	* @return  <tt>true</tt> if and only if the specified object
3793	<	*          is a key in this table, as determined by the
3794	<	*          <tt>equals</tt> method; <tt>false</tt> otherwise.
651	<	* @throws  NullPointerException  if the key is
652	<	*               <tt>null</tt>.
3791	>	* @param parallelismThreshold the (estimated) number of elements
3792	>	* needed for this operation to be executed in parallel
3793	>	* @param action the action
3794	>	* @since 1.8
3795		*/
3796	<	public boolean containsKey(Object key) {
3797	<	int hash = hash(key); // throws NullPointerException if key null
3798	<	return segmentFor(hash).containsKey(key, hash);
3796	>	public void forEachKey(long parallelismThreshold,
3797	>	Consumer<? super K> action) {
3798	>	if (action == null) throw new NullPointerException();
3799	>	new ForEachKeyTask<K,V>
3800	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3801	>	action).invoke();
3802		}
3803
3804		/**
3805	<	* Returns <tt>true</tt> if this map maps one or more keys to the
3806	<	* specified value. Note: This method requires a full internal
662	<	* traversal of the hash table, and so is much slower than
663	<	* method <tt>containsKey</tt>.
3805	>	* Performs the given action for each non-null transformation
3806	>	* of each key.
3807		*
3808	<	* @param value value whose presence in this map is to be tested.
3809	<	* @return <tt>true</tt> if this map maps one or more keys to the
3810	<	* specified value.
3811	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3808	>	* @param parallelismThreshold the (estimated) number of elements
3809	>	* needed for this operation to be executed in parallel
3810	>	* @param transformer a function returning the transformation
3811	>	* for an element, or null if there is no transformation (in
3812	>	* which case the action is not applied)
3813	>	* @param action the action
3814	>	* @param <U> the return type of the transformer
3815	>	* @since 1.8
3816		*/
3817	<	public boolean containsValue(Object value) {
3818	<	if (value == null)
3817	>	public <U> void forEachKey(long parallelismThreshold,
3818	>	Function<? super K, ? extends U> transformer,
3819	>	Consumer<? super U> action) {
3820	>	if (transformer == null || action == null)
3821		throw new NullPointerException();
3822	+	new ForEachTransformedKeyTask<K,V,U>
3823	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3824	+	transformer, action).invoke();
3825	+	}
3826
3827	<	int[] mc = new int[segments.length];
3828	<	for (;;) {
3829	<	int sum = 0;
3830	<	int mcsum = 0;
3831	<	for (int i = 0; i < segments.length; ++i) {
3832	<	int c = segments[i].count;
3833	<	mcsum += mc[i] = segments[i].modCount;
3834	<	if (segments[i].containsValue(value))
3835	<	return true;
3836	<	}
3837	<	boolean cleanSweep = true;
3838	<	if (mcsum != 0) {
3839	<	for (int i = 0; i < segments.length; ++i) {
3840	<	int c = segments[i].count;
3841	<	if (mc[i] != segments[i].modCount) {
3842	<	cleanSweep = false;
3843	<	break;
3844	<	}
3845	<	}
3846	<	}
3847	<	if (cleanSweep)
3848	<	return false;
696	<	}
3827	>	/**
3828	>	* Returns a non-null result from applying the given search
3829	>	* function on each key, or null if none. Upon success,
3830	>	* further element processing is suppressed and the results of
3831	>	* any other parallel invocations of the search function are
3832	>	* ignored.
3833	>	*
3834	>	* @param parallelismThreshold the (estimated) number of elements
3835	>	* needed for this operation to be executed in parallel
3836	>	* @param searchFunction a function returning a non-null
3837	>	* result on success, else null
3838	>	* @param <U> the return type of the search function
3839	>	* @return a non-null result from applying the given search
3840	>	* function on each key, or null if none
3841	>	* @since 1.8
3842	>	*/
3843	>	public <U> U searchKeys(long parallelismThreshold,
3844	>	Function<? super K, ? extends U> searchFunction) {
3845	>	if (searchFunction == null) throw new NullPointerException();
3846	>	return new SearchKeysTask<K,V,U>
3847	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3848	>	searchFunction, new AtomicReference<U>()).invoke();
3849		}
3850
3851		/**
3852	<	* Legacy method testing if some key maps into the specified value
3853	<	* in this table.  This method is identical in functionality to
3854	<	* {@link #containsValue}, and  exists solely to ensure
3855	<	* full compatibility with class {@link java.util.Hashtable},
3856	<	* which supported this method prior to introduction of the
3857	<	* Java Collections framework.
3852	>	* Returns the result of accumulating all keys using the given
3853	>	* reducer to combine values, or null if none.
3854	>	*
3855	>	* @param parallelismThreshold the (estimated) number of elements
3856	>	* needed for this operation to be executed in parallel
3857	>	* @param reducer a commutative associative combining function
3858	>	* @return the result of accumulating all keys using the given
3859	>	* reducer to combine values, or null if none
3860	>	* @since 1.8
3861	>	*/
3862	>	public K reduceKeys(long parallelismThreshold,
3863	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3864	>	if (reducer == null) throw new NullPointerException();
3865	>	return new ReduceKeysTask<K,V>
3866	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3867	>	null, reducer).invoke();
3868	>	}
3869
3870	<	* @param      value   a value to search for.
3871	<	* @return     <tt>true</tt> if and only if some key maps to the
3872	<	*             <tt>value</tt> argument in this table as
3873	<	*             determined by the <tt>equals</tt> method;
3874	<	*             <tt>false</tt> otherwise.
3875	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
3870	>	/**
3871	>	* Returns the result of accumulating the given transformation
3872	>	* of all keys using the given reducer to combine values, or
3873	>	* null if none.
3874	>	*
3875	>	* @param parallelismThreshold the (estimated) number of elements
3876	>	* needed for this operation to be executed in parallel
3877	>	* @param transformer a function returning the transformation
3878	>	* for an element, or null if there is no transformation (in
3879	>	* which case it is not combined)
3880	>	* @param reducer a commutative associative combining function
3881	>	* @param <U> the return type of the transformer
3882	>	* @return the result of accumulating the given transformation
3883	>	* of all keys
3884	>	* @since 1.8
3885		*/
3886	<	public boolean contains(Object value) {
3887	<	return containsValue(value);
3886	>	public <U> U reduceKeys(long parallelismThreshold,
3887	>	Function<? super K, ? extends U> transformer,
3888	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3889	>	if (transformer == null || reducer == null)
3890	>	throw new NullPointerException();
3891	>	return new MapReduceKeysTask<K,V,U>
3892	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3893	>	null, transformer, reducer).invoke();
3894		}
3895
3896		/**
3897	<	* Maps the specified <tt>key</tt> to the specified
3898	<	* <tt>value</tt> in this table. Neither the key nor the
3899	<	* value can be <tt>null</tt>. <p>
3897	>	* Returns the result of accumulating the given transformation
3898	>	* of all keys using the given reducer to combine values, and
3899	>	* the given basis as an identity value.
3900		*
3901	<	* The value can be retrieved by calling the <tt>get</tt> method
3902	<	* with a key that is equal to the original key.
3901	>	* @param parallelismThreshold the (estimated) number of elements
3902	>	* needed for this operation to be executed in parallel
3903	>	* @param transformer a function returning the transformation
3904	>	* for an element
3905	>	* @param basis the identity (initial default value) for the reduction
3906	>	* @param reducer a commutative associative combining function
3907	>	* @return the result of accumulating the given transformation
3908	>	* of all keys
3909	>	* @since 1.8
3910	>	*/
3911	>	public double reduceKeysToDouble(long parallelismThreshold,
3912	>	ToDoubleFunction<? super K> transformer,
3913	>	double basis,
3914	>	DoubleBinaryOperator reducer) {
3915	>	if (transformer == null || reducer == null)
3916	>	throw new NullPointerException();
3917	>	return new MapReduceKeysToDoubleTask<K,V>
3918	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3919	>	null, transformer, basis, reducer).invoke();
3920	>	}
3921	>
3922	>	/**
3923	>	* Returns the result of accumulating the given transformation
3924	>	* of all keys using the given reducer to combine values, and
3925	>	* the given basis as an identity value.
3926		*
3927	<	* @param      key     the table key.
3928	<	* @param      value   the value.
3929	<	* @return     the previous value of the specified key in this table,
3930	<	*             or <tt>null</tt> if it did not have one.
3931	<	* @throws  NullPointerException  if the key or value is
3932	<	*               <tt>null</tt>.
3927	>	* @param parallelismThreshold the (estimated) number of elements
3928	>	* needed for this operation to be executed in parallel
3929	>	* @param transformer a function returning the transformation
3930	>	* for an element
3931	>	* @param basis the identity (initial default value) for the reduction
3932	>	* @param reducer a commutative associative combining function
3933	>	* @return the result of accumulating the given transformation
3934	>	* of all keys
3935	>	* @since 1.8
3936		*/
3937	<	public V put(K key, V value) {
3938	<	if (value == null)
3937	>	public long reduceKeysToLong(long parallelismThreshold,
3938	>	ToLongFunction<? super K> transformer,
3939	>	long basis,
3940	>	LongBinaryOperator reducer) {
3941	>	if (transformer == null || reducer == null)
3942		throw new NullPointerException();
3943	<	int hash = hash(key);
3944	<	return segmentFor(hash).put(key, hash, value, false);
3943	>	return new MapReduceKeysToLongTask<K,V>
3944	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3945	>	null, transformer, basis, reducer).invoke();
3946		}
3947
3948		/**
3949	<	* If the specified key is not already associated
3950	<	* with a value, associate it with the given value.
3951	<	* This is equivalent to
744	<	* <pre>
745	<	*   if (!map.containsKey(key))
746	<	*      return map.put(key, value);
747	<	*   else
748	<	*      return map.get(key);
749	<	* </pre>
750	<	* Except that the action is performed atomically.
751	<	* @param key key with which the specified value is to be associated.
752	<	* @param value value to be associated with the specified key.
753	<	* @return previous value associated with specified key, or <tt>null</tt>
754	<	*         if there was no mapping for key.  A <tt>null</tt> return can
755	<	*         also indicate that the map previously associated <tt>null</tt>
756	<	*         with the specified key, if the implementation supports
757	<	*         <tt>null</tt> values.
758	<	*
759	<	* @throws UnsupportedOperationException if the <tt>put</tt> operation is
760	<	*            not supported by this map.
761	<	* @throws ClassCastException if the class of the specified key or value
762	<	*            prevents it from being stored in this map.
763	<	* @throws NullPointerException if the specified key or value is
764	<	*            <tt>null</tt>.
3949	>	* Returns the result of accumulating the given transformation
3950	>	* of all keys using the given reducer to combine values, and
3951	>	* the given basis as an identity value.
3952		*
3953	<	**/
3954	<	public V putIfAbsent(K key, V value) {
3955	<	if (value == null)
3953	>	* @param parallelismThreshold the (estimated) number of elements
3954	>	* needed for this operation to be executed in parallel
3955	>	* @param transformer a function returning the transformation
3956	>	* for an element
3957	>	* @param basis the identity (initial default value) for the reduction
3958	>	* @param reducer a commutative associative combining function
3959	>	* @return the result of accumulating the given transformation
3960	>	* of all keys
3961	>	* @since 1.8
3962	>	*/
3963	>	public int reduceKeysToInt(long parallelismThreshold,
3964	>	ToIntFunction<? super K> transformer,
3965	>	int basis,
3966	>	IntBinaryOperator reducer) {
3967	>	if (transformer == null || reducer == null)
3968		throw new NullPointerException();
3969	<	int hash = hash(key);
3970	<	return segmentFor(hash).put(key, hash, value, true);
3969	>	return new MapReduceKeysToIntTask<K,V>
3970	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3971	>	null, transformer, basis, reducer).invoke();
3972		}
3973
3974	+	/**
3975	+	* Performs the given action for each value.
3976	+	*
3977	+	* @param parallelismThreshold the (estimated) number of elements
3978	+	* needed for this operation to be executed in parallel
3979	+	* @param action the action
3980	+	* @since 1.8
3981	+	*/
3982	+	public void forEachValue(long parallelismThreshold,
3983	+	Consumer<? super V> action) {
3984	+	if (action == null)
3985	+	throw new NullPointerException();
3986	+	new ForEachValueTask<K,V>
3987	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3988	+	action).invoke();
3989	+	}
3990
3991		/**
3992	<	* Copies all of the mappings from the specified map to this one.
3992	>	* Performs the given action for each non-null transformation
3993	>	* of each value.
3994		*
3995	<	* These mappings replace any mappings that this map had for any of the
3996	<	* keys currently in the specified Map.
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, or null if there is no transformation (in
3999	>	* which case the action is not applied)
4000	>	* @param action the action
4001	>	* @param <U> the return type of the transformer
4002	>	* @since 1.8
4003	>	*/
4004	>	public <U> void forEachValue(long parallelismThreshold,
4005	>	Function<? super V, ? extends U> transformer,
4006	>	Consumer<? super U> action) {
4007	>	if (transformer == null || action == null)
4008	>	throw new NullPointerException();
4009	>	new ForEachTransformedValueTask<K,V,U>
4010	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4011	>	transformer, action).invoke();
4012	>	}
4013	>
4014	>	/**
4015	>	* Returns a non-null result from applying the given search
4016	>	* function on each value, or null if none.  Upon success,
4017	>	* further element processing is suppressed and the results of
4018	>	* any other parallel invocations of the search function are
4019	>	* ignored.
4020		*
4021	<	* @param t Mappings to be stored in this map.
4021	>	* @param parallelismThreshold the (estimated) number of elements
4022	>	* needed for this operation to be executed in parallel
4023	>	* @param searchFunction a function returning a non-null
4024	>	* result on success, else null
4025	>	* @param <U> the return type of the search function
4026	>	* @return a non-null result from applying the given search
4027	>	* function on each value, or null if none
4028	>	* @since 1.8
4029		*/
4030	<	public void putAll(Map<? extends K, ? extends V> t) {
4031	<	for (Iterator<Map.Entry<? extends K, ? extends V>> it = (Iterator<Map.Entry<? extends K, ? extends V>>) t.entrySet().iterator(); it.hasNext(); ) {
4032	<	Entry<? extends K, ? extends V> e = it.next();
4033	<	put(e.getKey(), e.getValue());
4034	<	}
4030	>	public <U> U searchValues(long parallelismThreshold,
4031	>	Function<? super V, ? extends U> searchFunction) {
4032	>	if (searchFunction == null) throw new NullPointerException();
4033	>	return new SearchValuesTask<K,V,U>
4034	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4035	>	searchFunction, new AtomicReference<U>()).invoke();
4036		}
4037
4038		/**
4039	<	* Removes the key (and its corresponding value) from this
4040	<	* table. This method does nothing if the key is not in the table.
4039	>	* Returns the result of accumulating all values using the
4040	>	* given reducer to combine values, or null if none.
4041		*
4042	<	* @param   key   the key that needs to be removed.
4043	<	* @return  the value to which the key had been mapped in this table,
4044	<	*          or <tt>null</tt> if the key did not have a mapping.
4045	<	* @throws  NullPointerException  if the key is
4046	<	*               <tt>null</tt>.
4042	>	* @param parallelismThreshold the (estimated) number of elements
4043	>	* needed for this operation to be executed in parallel
4044	>	* @param reducer a commutative associative combining function
4045	>	* @return the result of accumulating all values
4046	>	* @since 1.8
4047		*/
4048	<	public V remove(Object key) {
4049	<	int hash = hash(key);
4050	<	return segmentFor(hash).remove(key, hash, null);
4048	>	public V reduceValues(long parallelismThreshold,
4049	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4050	>	if (reducer == null) throw new NullPointerException();
4051	>	return new ReduceValuesTask<K,V>
4052	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4053	>	null, reducer).invoke();
4054		}
4055
4056		/**
4057	<	* Remove entry for key only if currently mapped to given value.
4058	<	* Acts as
4059	<	* <pre>
4060	<	*  if (map.get(key).equals(value)) {
4061	<	*     map.remove(key);
4062	<	*     return true;
4063	<	* } else return false;
4064	<	* </pre>
4065	<	* except that the action is performed atomically.
4066	<	* @param key key with which the specified value is associated.
4067	<	* @param value value associated with the specified key.
4068	<	* @return true if the value was removed
4069	<	* @throws NullPointerException if the specified key is
4070	<	*            <tt>null</tt>.
4057	>	* Returns the result of accumulating the given transformation
4058	>	* of all values using the given reducer to combine values, or
4059	>	* null if none.
4060	>	*
4061	>	* @param parallelismThreshold the (estimated) number of elements
4062	>	* needed for this operation to be executed in parallel
4063	>	* @param transformer a function returning the transformation
4064	>	* for an element, or null if there is no transformation (in
4065	>	* which case it is not combined)
4066	>	* @param reducer a commutative associative combining function
4067	>	* @param <U> the return type of the transformer
4068	>	* @return the result of accumulating the given transformation
4069	>	* of all values
4070	>	* @since 1.8
4071		*/
4072	<	public boolean remove(Object key, Object value) {
4073	<	int hash = hash(key);
4074	<	return segmentFor(hash).remove(key, hash, value) != null;
4072	>	public <U> U reduceValues(long parallelismThreshold,
4073	>	Function<? super V, ? extends U> transformer,
4074	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4075	>	if (transformer == null || reducer == null)
4076	>	throw new NullPointerException();
4077	>	return new MapReduceValuesTask<K,V,U>
4078	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4079	>	null, transformer, reducer).invoke();
4080		}
4081
4082		/**
4083	<	* Removes all mappings from this map.
4083	>	* Returns the result of accumulating the given transformation
4084	>	* of all values using the given reducer to combine values,
4085	>	* and the given basis as an identity value.
4086	>	*
4087	>	* @param parallelismThreshold the (estimated) number of elements
4088	>	* needed for this operation to be executed in parallel
4089	>	* @param transformer a function returning the transformation
4090	>	* for an element
4091	>	* @param basis the identity (initial default value) for the reduction
4092	>	* @param reducer a commutative associative combining function
4093	>	* @return the result of accumulating the given transformation
4094	>	* of all values
4095	>	* @since 1.8
4096		*/
4097	<	public void clear() {
4098	<	for (int i = 0; i < segments.length; ++i)
4099	<	segments[i].clear();
4097	>	public double reduceValuesToDouble(long parallelismThreshold,
4098	>	ToDoubleFunction<? super V> transformer,
4099	>	double basis,
4100	>	DoubleBinaryOperator reducer) {
4101	>	if (transformer == null || reducer == null)
4102	>	throw new NullPointerException();
4103	>	return new MapReduceValuesToDoubleTask<K,V>
4104	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4105	>	null, transformer, basis, reducer).invoke();
4106		}
4107
4108	+	/**
4109	+	* Returns the result of accumulating the given transformation
4110	+	* of all values using the given reducer to combine values,
4111	+	* and the given basis as an identity value.
4112	+	*
4113	+	* @param parallelismThreshold the (estimated) number of elements
4114	+	* needed for this operation to be executed in parallel
4115	+	* @param transformer a function returning the transformation
4116	+	* for an element
4117	+	* @param basis the identity (initial default value) for the reduction
4118	+	* @param reducer a commutative associative combining function
4119	+	* @return the result of accumulating the given transformation
4120	+	* of all values
4121	+	* @since 1.8
4122	+	*/
4123	+	public long reduceValuesToLong(long parallelismThreshold,
4124	+	ToLongFunction<? super V> transformer,
4125	+	long basis,
4126	+	LongBinaryOperator reducer) {
4127	+	if (transformer == null || reducer == null)
4128	+	throw new NullPointerException();
4129	+	return new MapReduceValuesToLongTask<K,V>
4130	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4131	+	null, transformer, basis, reducer).invoke();
4132	+	}
4133
4134		/**
4135	<	* Returns a shallow copy of this
4136	<	* <tt>ConcurrentHashMap</tt> instance: the keys and
4137	<	* values themselves are not cloned.
4135	>	* Returns the result of accumulating the given transformation
4136	>	* of all values using the given reducer to combine values,
4137	>	* and the given basis as an identity value.
4138		*
4139	<	* @return a shallow copy of this map.
4139	>	* @param parallelismThreshold the (estimated) number of elements
4140	>	* needed for this operation to be executed in parallel
4141	>	* @param transformer a function returning the transformation
4142	>	* for an element
4143	>	* @param basis the identity (initial default value) for the reduction
4144	>	* @param reducer a commutative associative combining function
4145	>	* @return the result of accumulating the given transformation
4146	>	* of all values
4147	>	* @since 1.8
4148		*/
4149	<	public Object clone() {
4150	<	// We cannot call super.clone, since it would share final
4151	<	// segments array, and there's no way to reassign finals.
4149	>	public int reduceValuesToInt(long parallelismThreshold,
4150	>	ToIntFunction<? super V> transformer,
4151	>	int basis,
4152	>	IntBinaryOperator reducer) {
4153	>	if (transformer == null || reducer == null)
4154	>	throw new NullPointerException();
4155	>	return new MapReduceValuesToIntTask<K,V>
4156	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4157	>	null, transformer, basis, reducer).invoke();
4158	>	}
4159
4160	<	float lf = segments[0].loadFactor;
4161	<	int segs = segments.length;
4162	<	int cap = (int)(size() / lf);
4163	<	if (cap < segs) cap = segs;
4164	<	ConcurrentHashMap<K,V> t = new ConcurrentHashMap<K,V>(cap, lf, segs);
4165	<	t.putAll(this);
4166	<	return t;
4160	>	/**
4161	>	* Performs the given action for each entry.
4162	>	*
4163	>	* @param parallelismThreshold the (estimated) number of elements
4164	>	* needed for this operation to be executed in parallel
4165	>	* @param action the action
4166	>	* @since 1.8
4167	>	*/
4168	>	public void forEachEntry(long parallelismThreshold,
4169	>	Consumer<? super Map.Entry<K,V>> action) {
4170	>	if (action == null) throw new NullPointerException();
4171	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4172	>	action).invoke();
4173		}
4174
4175		/**
4176	<	* Returns a set view of the keys contained in this map.  The set is
4177	<	* backed by the map, so changes to the map are reflected in the set, and
858	<	* vice-versa.  The set supports element removal, which removes the
859	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
860	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
861	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
862	<	* <tt>addAll</tt> operations.
863	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
864	<	* will never throw {@link java.util.ConcurrentModificationException},
865	<	* and guarantees to traverse elements as they existed upon
866	<	* construction of the iterator, and may (but is not guaranteed to)
867	<	* reflect any modifications subsequent to construction.
4176	>	* Performs the given action for each non-null transformation
4177	>	* of each entry.
4178		*
4179	<	* @return a set view of the keys contained in this map.
4179	>	* @param parallelismThreshold the (estimated) number of elements
4180	>	* needed for this operation to be executed in parallel
4181	>	* @param transformer a function returning the transformation
4182	>	* for an element, or null if there is no transformation (in
4183	>	* which case the action is not applied)
4184	>	* @param action the action
4185	>	* @param <U> the return type of the transformer
4186	>	* @since 1.8
4187		*/
4188	<	public Set<K> keySet() {
4189	<	Set<K> ks = keySet;
4190	<	return (ks != null) ? ks : (keySet = new KeySet());
4188	>	public <U> void forEachEntry(long parallelismThreshold,
4189	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4190	>	Consumer<? super U> action) {
4191	>	if (transformer == null || action == null)
4192	>	throw new NullPointerException();
4193	>	new ForEachTransformedEntryTask<K,V,U>
4194	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4195	>	transformer, action).invoke();
4196		}
4197
4198	+	/**
4199	+	* Returns a non-null result from applying the given search
4200	+	* function on each entry, or null if none.  Upon success,
4201	+	* further element processing is suppressed and the results of
4202	+	* any other parallel invocations of the search function are
4203	+	* ignored.
4204	+	*
4205	+	* @param parallelismThreshold the (estimated) number of elements
4206	+	* needed for this operation to be executed in parallel
4207	+	* @param searchFunction a function returning a non-null
4208	+	* result on success, else null
4209	+	* @param <U> the return type of the search function
4210	+	* @return a non-null result from applying the given search
4211	+	* function on each entry, or null if none
4212	+	* @since 1.8
4213	+	*/
4214	+	public <U> U searchEntries(long parallelismThreshold,
4215	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4216	+	if (searchFunction == null) throw new NullPointerException();
4217	+	return new SearchEntriesTask<K,V,U>
4218	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4219	+	searchFunction, new AtomicReference<U>()).invoke();
4220	+	}
4221
4222		/**
4223	<	* Returns a collection view of the values contained in this map.  The
4224	<	* collection is backed by the map, so changes to the map are reflected in
880	<	* the collection, and vice-versa.  The collection supports element
881	<	* removal, which removes the corresponding mapping from this map, via the
882	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
883	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
884	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
885	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
886	<	* will never throw {@link java.util.ConcurrentModificationException},
887	<	* and guarantees to traverse elements as they existed upon
888	<	* construction of the iterator, and may (but is not guaranteed to)
889	<	* reflect any modifications subsequent to construction.
4223	>	* Returns the result of accumulating all entries using the
4224	>	* given reducer to combine values, or null if none.
4225		*
4226	<	* @return a collection view of the values contained in this map.
4226	>	* @param parallelismThreshold the (estimated) number of elements
4227	>	* needed for this operation to be executed in parallel
4228	>	* @param reducer a commutative associative combining function
4229	>	* @return the result of accumulating all entries
4230	>	* @since 1.8
4231		*/
4232	<	public Collection<V> values() {
4233	<	Collection<V> vs = values;
4234	<	return (vs != null) ? vs : (values = new Values());
4232	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4233	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4234	>	if (reducer == null) throw new NullPointerException();
4235	>	return new ReduceEntriesTask<K,V>
4236	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4237	>	null, reducer).invoke();
4238		}
4239
4240	+	/**
4241	+	* Returns the result of accumulating the given transformation
4242	+	* of all entries using the given reducer to combine values,
4243	+	* or null if none.
4244	+	*
4245	+	* @param parallelismThreshold the (estimated) number of elements
4246	+	* needed for this operation to be executed in parallel
4247	+	* @param transformer a function returning the transformation
4248	+	* for an element, or null if there is no transformation (in
4249	+	* which case it is not combined)
4250	+	* @param reducer a commutative associative combining function
4251	+	* @param <U> the return type of the transformer
4252	+	* @return the result of accumulating the given transformation
4253	+	* of all entries
4254	+	* @since 1.8
4255	+	*/
4256	+	public <U> U reduceEntries(long parallelismThreshold,
4257	+	Function<Map.Entry<K,V>, ? extends U> transformer,
4258	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4259	+	if (transformer == null || reducer == null)
4260	+	throw new NullPointerException();
4261	+	return new MapReduceEntriesTask<K,V,U>
4262	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4263	+	null, transformer, reducer).invoke();
4264	+	}
4265
4266		/**
4267	<	* Returns a collection view of the mappings contained in this map.  Each
4268	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
4269	<	* collection is backed by the map, so changes to the map are reflected in
903	<	* the collection, and vice-versa.  The collection supports element
904	<	* removal, which removes the corresponding mapping from the map, via the
905	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
906	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
907	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
908	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
909	<	* will never throw {@link java.util.ConcurrentModificationException},
910	<	* and guarantees to traverse elements as they existed upon
911	<	* construction of the iterator, and may (but is not guaranteed to)
912	<	* reflect any modifications subsequent to construction.
4267	>	* Returns the result of accumulating the given transformation
4268	>	* of all entries using the given reducer to combine values,
4269	>	* and the given basis as an identity value.
4270		*
4271	<	* @return a collection view of the mappings contained in this map.
4271	>	* @param parallelismThreshold the (estimated) number of elements
4272	>	* needed for this operation to be executed in parallel
4273	>	* @param transformer a function returning the transformation
4274	>	* for an element
4275	>	* @param basis the identity (initial default value) for the reduction
4276	>	* @param reducer a commutative associative combining function
4277	>	* @return the result of accumulating the given transformation
4278	>	* of all entries
4279	>	* @since 1.8
4280		*/
4281	<	public Set<Map.Entry<K,V>> entrySet() {
4282	<	Set<Map.Entry<K,V>> es = entrySet;
4283	<	return (es != null) ? es : (entrySet = (Set<Map.Entry<K,V>>) (Set) new EntrySet());
4281	>	public double reduceEntriesToDouble(long parallelismThreshold,
4282	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4283	>	double basis,
4284	>	DoubleBinaryOperator reducer) {
4285	>	if (transformer == null || reducer == null)
4286	>	throw new NullPointerException();
4287	>	return new MapReduceEntriesToDoubleTask<K,V>
4288	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4289	>	null, transformer, basis, reducer).invoke();
4290		}
4291
4292	+	/**
4293	+	* Returns the result of accumulating the given transformation
4294	+	* of all entries using the given reducer to combine values,
4295	+	* and the given basis as an identity value.
4296	+	*
4297	+	* @param parallelismThreshold the (estimated) number of elements
4298	+	* needed for this operation to be executed in parallel
4299	+	* @param transformer a function returning the transformation
4300	+	* for an element
4301	+	* @param basis the identity (initial default value) for the reduction
4302	+	* @param reducer a commutative associative combining function
4303	+	* @return the result of accumulating the given transformation
4304	+	* of all entries
4305	+	* @since 1.8
4306	+	*/
4307	+	public long reduceEntriesToLong(long parallelismThreshold,
4308	+	ToLongFunction<Map.Entry<K,V>> transformer,
4309	+	long basis,
4310	+	LongBinaryOperator reducer) {
4311	+	if (transformer == null || reducer == null)
4312	+	throw new NullPointerException();
4313	+	return new MapReduceEntriesToLongTask<K,V>
4314	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4315	+	null, transformer, basis, reducer).invoke();
4316	+	}
4317
4318		/**
4319	<	* Returns an enumeration of the keys in this table.
4319	>	* Returns the result of accumulating the given transformation
4320	>	* of all entries using the given reducer to combine values,
4321	>	* and the given basis as an identity value.
4322		*
4323	<	* @return  an enumeration of the keys in this table.
4324	<	* @see     #keySet
4323	>	* @param parallelismThreshold the (estimated) number of elements
4324	>	* needed for this operation to be executed in parallel
4325	>	* @param transformer a function returning the transformation
4326	>	* for an element
4327	>	* @param basis the identity (initial default value) for the reduction
4328	>	* @param reducer a commutative associative combining function
4329	>	* @return the result of accumulating the given transformation
4330	>	* of all entries
4331	>	* @since 1.8
4332		*/
4333	<	public Enumeration<K> keys() {
4334	<	return new KeyIterator();
4333	>	public int reduceEntriesToInt(long parallelismThreshold,
4334	>	ToIntFunction<Map.Entry<K,V>> transformer,
4335	>	int basis,
4336	>	IntBinaryOperator reducer) {
4337	>	if (transformer == null || reducer == null)
4338	>	throw new NullPointerException();
4339	>	return new MapReduceEntriesToIntTask<K,V>
4340	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4341	>	null, transformer, basis, reducer).invoke();
4342		}
4343
4344	+
4345	+	/* ----------------Views -------------- */
4346	+
4347		/**
4348	<	* Returns an enumeration of the values in this table.
4349	<	* Use the Enumeration methods on the returned object to fetch the elements
4350	<	* sequentially.
4348	>	* Base class for views.
4349	>	*/
4350	>	abstract static class CollectionView<K,V,E>
4351	>	implements Collection<E>, java.io.Serializable {
4352	>	private static final long serialVersionUID = 7249069246763182397L;
4353	>	final ConcurrentHashMap<K,V> map;
4354	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4355	>
4356	>	/**
4357	>	* Returns the map backing this view.
4358	>	*
4359	>	* @return the map backing this view
4360	>	*/
4361	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4362	>
4363	>	/**
4364	>	* Removes all of the elements from this view, by removing all
4365	>	* the mappings from the map backing this view.
4366	>	*/
4367	>	public final void clear()      { map.clear(); }
4368	>	public final int size()        { return map.size(); }
4369	>	public final boolean isEmpty() { return map.isEmpty(); }
4370	>
4371	>	// implementations below rely on concrete classes supplying these
4372	>	// abstract methods
4373	>	/**
4374	>	* Returns an iterator over the elements in this collection.
4375	>	*
4376	>	* <p>The returned iterator is
4377	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4378	>	*
4379	>	* @return an iterator over the elements in this collection
4380	>	*/
4381	>	public abstract Iterator<E> iterator();
4382	>	public abstract boolean contains(Object o);
4383	>	public abstract boolean remove(Object o);
4384	>
4385	>	private static final String oomeMsg = "Required array size too large";
4386	>
4387	>	public final Object[] toArray() {
4388	>	long sz = map.mappingCount();
4389	>	if (sz > MAX_ARRAY_SIZE)
4390	>	throw new OutOfMemoryError(oomeMsg);
4391	>	int n = (int)sz;
4392	>	Object[] r = new Object[n];
4393	>	int i = 0;
4394	>	for (E e : this) {
4395	>	if (i == n) {
4396	>	if (n >= MAX_ARRAY_SIZE)
4397	>	throw new OutOfMemoryError(oomeMsg);
4398	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4399	>	n = MAX_ARRAY_SIZE;
4400	>	else
4401	>	n += (n >>> 1) + 1;
4402	>	r = Arrays.copyOf(r, n);
4403	>	}
4404	>	r[i++] = e;
4405	>	}
4406	>	return (i == n) ? r : Arrays.copyOf(r, i);
4407	>	}
4408	>
4409	>	@SuppressWarnings("unchecked")
4410	>	public final <T> T[] toArray(T[] a) {
4411	>	long sz = map.mappingCount();
4412	>	if (sz > MAX_ARRAY_SIZE)
4413	>	throw new OutOfMemoryError(oomeMsg);
4414	>	int m = (int)sz;
4415	>	T[] r = (a.length >= m) ? a :
4416	>	(T[])java.lang.reflect.Array
4417	>	.newInstance(a.getClass().getComponentType(), m);
4418	>	int n = r.length;
4419	>	int i = 0;
4420	>	for (E e : this) {
4421	>	if (i == n) {
4422	>	if (n >= MAX_ARRAY_SIZE)
4423	>	throw new OutOfMemoryError(oomeMsg);
4424	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4425	>	n = MAX_ARRAY_SIZE;
4426	>	else
4427	>	n += (n >>> 1) + 1;
4428	>	r = Arrays.copyOf(r, n);
4429	>	}
4430	>	r[i++] = (T)e;
4431	>	}
4432	>	if (a == r && i < n) {
4433	>	r[i] = null; // null-terminate
4434	>	return r;
4435	>	}
4436	>	return (i == n) ? r : Arrays.copyOf(r, i);
4437	>	}
4438	>
4439	>	/**
4440	>	* Returns a string representation of this collection.
4441	>	* The string representation consists of the string representations
4442	>	* of the collection's elements in the order they are returned by
4443	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4444	>	* Adjacent elements are separated by the characters {@code ", "}
4445	>	* (comma and space).  Elements are converted to strings as by
4446	>	* {@link String#valueOf(Object)}.
4447	>	*
4448	>	* @return a string representation of this collection
4449	>	*/
4450	>	public final String toString() {
4451	>	StringBuilder sb = new StringBuilder();
4452	>	sb.append('[');
4453	>	Iterator<E> it = iterator();
4454	>	if (it.hasNext()) {
4455	>	for (;;) {
4456	>	Object e = it.next();
4457	>	sb.append(e == this ? "(this Collection)" : e);
4458	>	if (!it.hasNext())
4459	>	break;
4460	>	sb.append(',').append(' ');
4461	>	}
4462	>	}
4463	>	return sb.append(']').toString();
4464	>	}
4465	>
4466	>	public final boolean containsAll(Collection<?> c) {
4467	>	if (c != this) {
4468	>	for (Object e : c) {
4469	>	if (e == null || !contains(e))
4470	>	return false;
4471	>	}
4472	>	}
4473	>	return true;
4474	>	}
4475	>
4476	>	public final boolean removeAll(Collection<?> c) {
4477	>	if (c == null) throw new NullPointerException();
4478	>	boolean modified = false;
4479	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4480	>	if (c.contains(it.next())) {
4481	>	it.remove();
4482	>	modified = true;
4483	>	}
4484	>	}
4485	>	return modified;
4486	>	}
4487	>
4488	>	public final boolean retainAll(Collection<?> c) {
4489	>	if (c == null) throw new NullPointerException();
4490	>	boolean modified = false;
4491	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4492	>	if (!c.contains(it.next())) {
4493	>	it.remove();
4494	>	modified = true;
4495	>	}
4496	>	}
4497	>	return modified;
4498	>	}
4499	>
4500	>	}
4501	>
4502	>	/**
4503	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4504	>	* which additions may optionally be enabled by mapping to a
4505	>	* common value.  This class cannot be directly instantiated.
4506	>	* See {@link #keySet() keySet()},
4507	>	* {@link #keySet(Object) keySet(V)},
4508	>	* {@link #newKeySet() newKeySet()},
4509	>	* {@link #newKeySet(int) newKeySet(int)}.
4510		*
4511	<	* @return  an enumeration of the values in this table.
938	<	* @see     #values
4511	>	* @since 1.8
4512		*/
4513	<	public Enumeration<V> elements() {
4514	<	return new ValueIterator();
4513	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4514	>	implements Set<K>, java.io.Serializable {
4515	>	private static final long serialVersionUID = 7249069246763182397L;
4516	>	private final V value;
4517	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4518	>	super(map);
4519	>	this.value = value;
4520	>	}
4521	>
4522	>	/**
4523	>	* Returns the default mapped value for additions,
4524	>	* or {@code null} if additions are not supported.
4525	>	*
4526	>	* @return the default mapped value for additions, or {@code null}
4527	>	* if not supported
4528	>	*/
4529	>	public V getMappedValue() { return value; }
4530	>
4531	>	/**
4532	>	* {@inheritDoc}
4533	>	* @throws NullPointerException if the specified key is null
4534	>	*/
4535	>	public boolean contains(Object o) { return map.containsKey(o); }
4536	>
4537	>	/**
4538	>	* Removes the key from this map view, by removing the key (and its
4539	>	* corresponding value) from the backing map.  This method does
4540	>	* nothing if the key is not in the map.
4541	>	*
4542	>	* @param  o the key to be removed from the backing map
4543	>	* @return {@code true} if the backing map contained the specified key
4544	>	* @throws NullPointerException if the specified key is null
4545	>	*/
4546	>	public boolean remove(Object o) { return map.remove(o) != null; }
4547	>
4548	>	/**
4549	>	* @return an iterator over the keys of the backing map
4550	>	*/
4551	>	public Iterator<K> iterator() {
4552	>	Node<K,V>[] t;
4553	>	ConcurrentHashMap<K,V> m = map;
4554	>	int f = (t = m.table) == null ? 0 : t.length;
4555	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4556	>	}
4557	>
4558	>	/**
4559	>	* Adds the specified key to this set view by mapping the key to
4560	>	* the default mapped value in the backing map, if defined.
4561	>	*
4562	>	* @param e key to be added
4563	>	* @return {@code true} if this set changed as a result of the call
4564	>	* @throws NullPointerException if the specified key is null
4565	>	* @throws UnsupportedOperationException if no default mapped value
4566	>	* for additions was provided
4567	>	*/
4568	>	public boolean add(K e) {
4569	>	V v;
4570	>	if ((v = value) == null)
4571	>	throw new UnsupportedOperationException();
4572	>	return map.putVal(e, v, true) == null;
4573	>	}
4574	>
4575	>	/**
4576	>	* Adds all of the elements in the specified collection to this set,
4577	>	* as if by calling {@link #add} on each one.
4578	>	*
4579	>	* @param c the elements to be inserted into this set
4580	>	* @return {@code true} if this set changed as a result of the call
4581	>	* @throws NullPointerException if the collection or any of its
4582	>	* elements are {@code null}
4583	>	* @throws UnsupportedOperationException if no default mapped value
4584	>	* for additions was provided
4585	>	*/
4586	>	public boolean addAll(Collection<? extends K> c) {
4587	>	boolean added = false;
4588	>	V v;
4589	>	if ((v = value) == null)
4590	>	throw new UnsupportedOperationException();
4591	>	for (K e : c) {
4592	>	if (map.putVal(e, v, true) == null)
4593	>	added = true;
4594	>	}
4595	>	return added;
4596	>	}
4597	>
4598	>	public int hashCode() {
4599	>	int h = 0;
4600	>	for (K e : this)
4601	>	h += e.hashCode();
4602	>	return h;
4603	>	}
4604	>
4605	>	public boolean equals(Object o) {
4606	>	Set<?> c;
4607	>	return ((o instanceof Set) &&
4608	>	((c = (Set<?>)o) == this ||
4609	>	(containsAll(c) && c.containsAll(this))));
4610	>	}
4611	>
4612	>	public Spliterator<K> spliterator() {
4613	>	Node<K,V>[] t;
4614	>	ConcurrentHashMap<K,V> m = map;
4615	>	long n = m.sumCount();
4616	>	int f = (t = m.table) == null ? 0 : t.length;
4617	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4618	>	}
4619	>
4620	>	public void forEach(Consumer<? super K> action) {
4621	>	if (action == null) throw new NullPointerException();
4622	>	Node<K,V>[] t;
4623	>	if ((t = map.table) != null) {
4624	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4625	>	for (Node<K,V> p; (p = it.advance()) != null; )
4626	>	action.accept(p.key);
4627	>	}
4628	>	}
4629		}
4630
4631	<	/* ---------------- Iterator Support -------------- */
4631	>	/**
4632	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4633	>	* values, in which additions are disabled. This class cannot be
4634	>	* directly instantiated. See {@link #values()}.
4635	>	*/
4636	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4637	>	implements Collection<V>, java.io.Serializable {
4638	>	private static final long serialVersionUID = 2249069246763182397L;
4639	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4640	>	public final boolean contains(Object o) {
4641	>	return map.containsValue(o);
4642	>	}
4643
4644	<	private abstract class HashIterator {
4645	<	private int nextSegmentIndex;
4646	<	private int nextTableIndex;
4647	<	private HashEntry[] currentTable;
4648	<	private HashEntry<K, V> nextEntry;
4649	<	private HashEntry<K, V> lastReturned;
4644	>	public final boolean remove(Object o) {
4645	>	if (o != null) {
4646	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4647	>	if (o.equals(it.next())) {
4648	>	it.remove();
4649	>	return true;
4650	>	}
4651	>	}
4652	>	}
4653	>	return false;
4654	>	}
4655
4656	<	private HashIterator() {
4657	<	nextSegmentIndex = segments.length - 1;
4658	<	nextTableIndex = -1;
4659	<	advance();
4656	>	public final Iterator<V> iterator() {
4657	>	ConcurrentHashMap<K,V> m = map;
4658	>	Node<K,V>[] t;
4659	>	int f = (t = m.table) == null ? 0 : t.length;
4660	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4661	>	}
4662	>
4663	>	public final boolean add(V e) {
4664	>	throw new UnsupportedOperationException();
4665	>	}
4666	>	public final boolean addAll(Collection<? extends V> c) {
4667	>	throw new UnsupportedOperationException();
4668	>	}
4669	>
4670	>	public Spliterator<V> spliterator() {
4671	>	Node<K,V>[] t;
4672	>	ConcurrentHashMap<K,V> m = map;
4673	>	long n = m.sumCount();
4674	>	int f = (t = m.table) == null ? 0 : t.length;
4675	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4676	>	}
4677	>
4678	>	public void forEach(Consumer<? super V> action) {
4679	>	if (action == null) throw new NullPointerException();
4680	>	Node<K,V>[] t;
4681	>	if ((t = map.table) != null) {
4682	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4683	>	for (Node<K,V> p; (p = it.advance()) != null; )
4684	>	action.accept(p.val);
4685	>	}
4686		}
4687	+	}
4688
4689	<	public boolean hasMoreElements() { return hasNext(); }
4689	>	/**
4690	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4691	>	* entries.  This class cannot be directly instantiated. See
4692	>	* {@link #entrySet()}.
4693	>	*/
4694	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4695	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4696	>	private static final long serialVersionUID = 2249069246763182397L;
4697	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4698
4699	<	private void advance() {
4700	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
4701	<	return;
4699	>	public boolean contains(Object o) {
4700	>	Object k, v, r; Map.Entry<?,?> e;
4701	>	return ((o instanceof Map.Entry) &&
4702	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4703	>	(r = map.get(k)) != null &&
4704	>	(v = e.getValue()) != null &&
4705	>	(v == r || v.equals(r)));
4706	>	}
4707
4708	<	while (nextTableIndex >= 0) {
4709	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[nextTableIndex--]) != null)
4710	<	return;
4708	>	public boolean remove(Object o) {
4709	>	Object k, v; Map.Entry<?,?> e;
4710	>	return ((o instanceof Map.Entry) &&
4711	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4712	>	(v = e.getValue()) != null &&
4713	>	map.remove(k, v));
4714	>	}
4715	>
4716	>	/**
4717	>	* @return an iterator over the entries of the backing map
4718	>	*/
4719	>	public Iterator<Map.Entry<K,V>> iterator() {
4720	>	ConcurrentHashMap<K,V> m = map;
4721	>	Node<K,V>[] t;
4722	>	int f = (t = m.table) == null ? 0 : t.length;
4723	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4724	>	}
4725	>
4726	>	public boolean add(Entry<K,V> e) {
4727	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4728	>	}
4729	>
4730	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4731	>	boolean added = false;
4732	>	for (Entry<K,V> e : c) {
4733	>	if (add(e))
4734	>	added = true;
4735		}
4736	+	return added;
4737	+	}
4738
4739	<	while (nextSegmentIndex >= 0) {
4740	<	Segment<K,V> seg = (Segment<K,V>)segments[nextSegmentIndex--];
4741	<	if (seg.count != 0) {
4742	<	currentTable = seg.table;
4743	<	for (int j = currentTable.length - 1; j >= 0; --j) {
4744	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[j]) != null) {
4745	<	nextTableIndex = j - 1;
4746	<	return;
4747	<	}
4739	>	public final int hashCode() {
4740	>	int h = 0;
4741	>	Node<K,V>[] t;
4742	>	if ((t = map.table) != null) {
4743	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4744	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4745	>	h += p.hashCode();
4746	>	}
4747	>	}
4748	>	return h;
4749	>	}
4750	>
4751	>	public final boolean equals(Object o) {
4752	>	Set<?> c;
4753	>	return ((o instanceof Set) &&
4754	>	((c = (Set<?>)o) == this ||
4755	>	(containsAll(c) && c.containsAll(this))));
4756	>	}
4757	>
4758	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4759	>	Node<K,V>[] t;
4760	>	ConcurrentHashMap<K,V> m = map;
4761	>	long n = m.sumCount();
4762	>	int f = (t = m.table) == null ? 0 : t.length;
4763	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4764	>	}
4765	>
4766	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4767	>	if (action == null) throw new NullPointerException();
4768	>	Node<K,V>[] t;
4769	>	if ((t = map.table) != null) {
4770	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4771	>	for (Node<K,V> p; (p = it.advance()) != null; )
4772	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4773	>	}
4774	>	}
4775	>
4776	>	}
4777	>
4778	>	// -------------------------------------------------------
4779	>
4780	>	/**
4781	>	* Base class for bulk tasks. Repeats some fields and code from
4782	>	* class Traverser, because we need to subclass CountedCompleter.
4783	>	*/
4784	>	@SuppressWarnings("serial")
4785	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4786	>	Node<K,V>[] tab;        // same as Traverser
4787	>	Node<K,V> next;
4788	>	TableStack<K,V> stack, spare;
4789	>	int index;
4790	>	int baseIndex;
4791	>	int baseLimit;
4792	>	final int baseSize;
4793	>	int batch;              // split control
4794	>
4795	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4796	>	super(par);
4797	>	this.batch = b;
4798	>	this.index = this.baseIndex = i;
4799	>	if ((this.tab = t) == null)
4800	>	this.baseSize = this.baseLimit = 0;
4801	>	else if (par == null)
4802	>	this.baseSize = this.baseLimit = t.length;
4803	>	else {
4804	>	this.baseLimit = f;
4805	>	this.baseSize = par.baseSize;
4806	>	}
4807	>	}
4808	>
4809	>	/**
4810	>	* Same as Traverser version
4811	>	*/
4812	>	final Node<K,V> advance() {
4813	>	Node<K,V> e;
4814	>	if ((e = next) != null)
4815	>	e = e.next;
4816	>	for (;;) {
4817	>	Node<K,V>[] t; int i, n;
4818	>	if (e != null)
4819	>	return next = e;
4820	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4821	>	(n = t.length) <= (i = index) || i < 0)
4822	>	return next = null;
4823	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4824	>	if (e instanceof ForwardingNode) {
4825	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4826	>	e = null;
4827	>	pushState(t, i, n);
4828	>	continue;
4829		}
4830	+	else if (e instanceof TreeBin)
4831	+	e = ((TreeBin<K,V>)e).first;
4832	+	else
4833	+	e = null;
4834		}
4835	+	if (stack != null)
4836	+	recoverState(n);
4837	+	else if ((index = i + baseSize) >= n)
4838	+	index = ++baseIndex;
4839		}
4840		}
4841
4842	<	public boolean hasNext() { return nextEntry != null; }
4842	>	private void pushState(Node<K,V>[] t, int i, int n) {
4843	>	TableStack<K,V> s = spare;
4844	>	if (s != null)
4845	>	spare = s.next;
4846	>	else
4847	>	s = new TableStack<K,V>();
4848	>	s.tab = t;
4849	>	s.length = n;
4850	>	s.index = i;
4851	>	s.next = stack;
4852	>	stack = s;
4853	>	}
4854	>
4855	>	private void recoverState(int n) {
4856	>	TableStack<K,V> s; int len;
4857	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4858	>	n = len;
4859	>	index = s.index;
4860	>	tab = s.tab;
4861	>	s.tab = null;
4862	>	TableStack<K,V> next = s.next;
4863	>	s.next = spare; // save for reuse
4864	>	stack = next;
4865	>	spare = s;
4866	>	}
4867	>	if (s == null && (index += baseSize) >= n)
4868	>	index = ++baseIndex;
4869	>	}
4870	>	}
4871
4872	<	HashEntry<K,V> nextEntry() {
4873	<	if (nextEntry == null)
4874	<	throw new NoSuchElementException();
4875	<	lastReturned = nextEntry;
4876	<	advance();
4877	<	return lastReturned;
4872	>	/*
4873	>	* Task classes. Coded in a regular but ugly format/style to
4874	>	* simplify checks that each variant differs in the right way from
4875	>	* others. The null screenings exist because compilers cannot tell
4876	>	* that we've already null-checked task arguments, so we force
4877	>	* simplest hoisted bypass to help avoid convoluted traps.
4878	>	*/
4879	>	@SuppressWarnings("serial")
4880	>	static final class ForEachKeyTask<K,V>
4881	>	extends BulkTask<K,V,Void> {
4882	>	final Consumer<? super K> action;
4883	>	ForEachKeyTask
4884	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4885	>	Consumer<? super K> action) {
4886	>	super(p, b, i, f, t);
4887	>	this.action = action;
4888	>	}
4889	>	public final void compute() {
4890	>	final Consumer<? super K> action;
4891	>	if ((action = this.action) != null) {
4892	>	for (int i = baseIndex, f, h; batch > 0 &&
4893	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4894	>	addToPendingCount(1);
4895	>	new ForEachKeyTask<K,V>
4896	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4897	>	action).fork();
4898	>	}
4899	>	for (Node<K,V> p; (p = advance()) != null;)
4900	>	action.accept(p.key);
4901	>	propagateCompletion();
4902	>	}
4903		}
4904	+	}
4905
4906	<	public void remove() {
4907	<	if (lastReturned == null)
4908	<	throw new IllegalStateException();
4909	<	ConcurrentHashMap.this.remove(lastReturned.key);
4910	<	lastReturned = null;
4906	>	@SuppressWarnings("serial")
4907	>	static final class ForEachValueTask<K,V>
4908	>	extends BulkTask<K,V,Void> {
4909	>	final Consumer<? super V> action;
4910	>	ForEachValueTask
4911	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4912	>	Consumer<? super V> action) {
4913	>	super(p, b, i, f, t);
4914	>	this.action = action;
4915	>	}
4916	>	public final void compute() {
4917	>	final Consumer<? super V> action;
4918	>	if ((action = this.action) != null) {
4919	>	for (int i = baseIndex, f, h; batch > 0 &&
4920	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4921	>	addToPendingCount(1);
4922	>	new ForEachValueTask<K,V>
4923	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4924	>	action).fork();
4925	>	}
4926	>	for (Node<K,V> p; (p = advance()) != null;)
4927	>	action.accept(p.val);
4928	>	propagateCompletion();
4929	>	}
4930		}
4931		}
4932
4933	<	private class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
4934	<	public K next() { return super.nextEntry().key; }
4935	<	public K nextElement() { return super.nextEntry().key; }
4933	>	@SuppressWarnings("serial")
4934	>	static final class ForEachEntryTask<K,V>
4935	>	extends BulkTask<K,V,Void> {
4936	>	final Consumer<? super Entry<K,V>> action;
4937	>	ForEachEntryTask
4938	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4939	>	Consumer<? super Entry<K,V>> action) {
4940	>	super(p, b, i, f, t);
4941	>	this.action = action;
4942	>	}
4943	>	public final void compute() {
4944	>	final Consumer<? super Entry<K,V>> action;
4945	>	if ((action = this.action) != null) {
4946	>	for (int i = baseIndex, f, h; batch > 0 &&
4947	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4948	>	addToPendingCount(1);
4949	>	new ForEachEntryTask<K,V>
4950	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4951	>	action).fork();
4952	>	}
4953	>	for (Node<K,V> p; (p = advance()) != null; )
4954	>	action.accept(p);
4955	>	propagateCompletion();
4956	>	}
4957	>	}
4958		}
4959
4960	<	private class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
4961	<	public V next() { return super.nextEntry().value; }
4962	<	public V nextElement() { return super.nextEntry().value; }
4960	>	@SuppressWarnings("serial")
4961	>	static final class ForEachMappingTask<K,V>
4962	>	extends BulkTask<K,V,Void> {
4963	>	final BiConsumer<? super K, ? super V> action;
4964	>	ForEachMappingTask
4965	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4966	>	BiConsumer<? super K,? super V> action) {
4967	>	super(p, b, i, f, t);
4968	>	this.action = action;
4969	>	}
4970	>	public final void compute() {
4971	>	final BiConsumer<? super K, ? super V> action;
4972	>	if ((action = this.action) != null) {
4973	>	for (int i = baseIndex, f, h; batch > 0 &&
4974	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4975	>	addToPendingCount(1);
4976	>	new ForEachMappingTask<K,V>
4977	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4978	>	action).fork();
4979	>	}
4980	>	for (Node<K,V> p; (p = advance()) != null; )
4981	>	action.accept(p.key, p.val);
4982	>	propagateCompletion();
4983	>	}
4984	>	}
4985		}
4986
4987	<	private class EntryIterator extends HashIterator implements Iterator<Entry<K,V>> {
4988	<	public Map.Entry<K,V> next() { return super.nextEntry(); }
4987	>	@SuppressWarnings("serial")
4988	>	static final class ForEachTransformedKeyTask<K,V,U>
4989	>	extends BulkTask<K,V,Void> {
4990	>	final Function<? super K, ? extends U> transformer;
4991	>	final Consumer<? super U> action;
4992	>	ForEachTransformedKeyTask
4993	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4994	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4995	>	super(p, b, i, f, t);
4996	>	this.transformer = transformer; this.action = action;
4997	>	}
4998	>	public final void compute() {
4999	>	final Function<? super K, ? extends U> transformer;
5000	>	final Consumer<? super U> action;
5001	>	if ((transformer = this.transformer) != null &&
5002	>	(action = this.action) != null) {
5003	>	for (int i = baseIndex, f, h; batch > 0 &&
5004	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5005	>	addToPendingCount(1);
5006	>	new ForEachTransformedKeyTask<K,V,U>
5007	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5008	>	transformer, action).fork();
5009	>	}
5010	>	for (Node<K,V> p; (p = advance()) != null; ) {
5011	>	U u;
5012	>	if ((u = transformer.apply(p.key)) != null)
5013	>	action.accept(u);
5014	>	}
5015	>	propagateCompletion();
5016	>	}
5017	>	}
5018		}
5019
5020	<	private class KeySet extends AbstractSet<K> {
5021	<	public Iterator<K> iterator() {
5022	<	return new KeyIterator();
5020	>	@SuppressWarnings("serial")
5021	>	static final class ForEachTransformedValueTask<K,V,U>
5022	>	extends BulkTask<K,V,Void> {
5023	>	final Function<? super V, ? extends U> transformer;
5024	>	final Consumer<? super U> action;
5025	>	ForEachTransformedValueTask
5026	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5027	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5028	>	super(p, b, i, f, t);
5029	>	this.transformer = transformer; this.action = action;
5030	>	}
5031	>	public final void compute() {
5032	>	final Function<? super V, ? extends U> transformer;
5033	>	final Consumer<? super U> action;
5034	>	if ((transformer = this.transformer) != null &&
5035	>	(action = this.action) != null) {
5036	>	for (int i = baseIndex, f, h; batch > 0 &&
5037	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5038	>	addToPendingCount(1);
5039	>	new ForEachTransformedValueTask<K,V,U>
5040	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5041	>	transformer, action).fork();
5042	>	}
5043	>	for (Node<K,V> p; (p = advance()) != null; ) {
5044	>	U u;
5045	>	if ((u = transformer.apply(p.val)) != null)
5046	>	action.accept(u);
5047	>	}
5048	>	propagateCompletion();
5049	>	}
5050		}
5051	<	public int size() {
5052	<	return ConcurrentHashMap.this.size();
5051	>	}
5052	>
5053	>	@SuppressWarnings("serial")
5054	>	static final class ForEachTransformedEntryTask<K,V,U>
5055	>	extends BulkTask<K,V,Void> {
5056	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5057	>	final Consumer<? super U> action;
5058	>	ForEachTransformedEntryTask
5059	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5060	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5061	>	super(p, b, i, f, t);
5062	>	this.transformer = transformer; this.action = action;
5063	>	}
5064	>	public final void compute() {
5065	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5066	>	final Consumer<? super U> action;
5067	>	if ((transformer = this.transformer) != null &&
5068	>	(action = this.action) != null) {
5069	>	for (int i = baseIndex, f, h; batch > 0 &&
5070	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5071	>	addToPendingCount(1);
5072	>	new ForEachTransformedEntryTask<K,V,U>
5073	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5074	>	transformer, action).fork();
5075	>	}
5076	>	for (Node<K,V> p; (p = advance()) != null; ) {
5077	>	U u;
5078	>	if ((u = transformer.apply(p)) != null)
5079	>	action.accept(u);
5080	>	}
5081	>	propagateCompletion();
5082	>	}
5083		}
5084	<	public boolean contains(Object o) {
5085	<	return ConcurrentHashMap.this.containsKey(o);
5084	>	}
5085	>
5086	>	@SuppressWarnings("serial")
5087	>	static final class ForEachTransformedMappingTask<K,V,U>
5088	>	extends BulkTask<K,V,Void> {
5089	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5090	>	final Consumer<? super U> action;
5091	>	ForEachTransformedMappingTask
5092	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5093	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5094	>	Consumer<? super U> action) {
5095	>	super(p, b, i, f, t);
5096	>	this.transformer = transformer; this.action = action;
5097	>	}
5098	>	public final void compute() {
5099	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5100	>	final Consumer<? super U> action;
5101	>	if ((transformer = this.transformer) != null &&
5102	>	(action = this.action) != null) {
5103	>	for (int i = baseIndex, f, h; batch > 0 &&
5104	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5105	>	addToPendingCount(1);
5106	>	new ForEachTransformedMappingTask<K,V,U>
5107	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5108	>	transformer, action).fork();
5109	>	}
5110	>	for (Node<K,V> p; (p = advance()) != null; ) {
5111	>	U u;
5112	>	if ((u = transformer.apply(p.key, p.val)) != null)
5113	>	action.accept(u);
5114	>	}
5115	>	propagateCompletion();
5116	>	}
5117		}
5118	<	public boolean remove(Object o) {
5119	<	return ConcurrentHashMap.this.remove(o) != null;
5118	>	}
5119	>
5120	>	@SuppressWarnings("serial")
5121	>	static final class SearchKeysTask<K,V,U>
5122	>	extends BulkTask<K,V,U> {
5123	>	final Function<? super K, ? extends U> searchFunction;
5124	>	final AtomicReference<U> result;
5125	>	SearchKeysTask
5126	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5127	>	Function<? super K, ? extends U> searchFunction,
5128	>	AtomicReference<U> result) {
5129	>	super(p, b, i, f, t);
5130	>	this.searchFunction = searchFunction; this.result = result;
5131	>	}
5132	>	public final U getRawResult() { return result.get(); }
5133	>	public final void compute() {
5134	>	final Function<? super K, ? extends U> searchFunction;
5135	>	final AtomicReference<U> result;
5136	>	if ((searchFunction = this.searchFunction) != null &&
5137	>	(result = this.result) != null) {
5138	>	for (int i = baseIndex, f, h; batch > 0 &&
5139	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5140	>	if (result.get() != null)
5141	>	return;
5142	>	addToPendingCount(1);
5143	>	new SearchKeysTask<K,V,U>
5144	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5145	>	searchFunction, result).fork();
5146	>	}
5147	>	while (result.get() == null) {
5148	>	U u;
5149	>	Node<K,V> p;
5150	>	if ((p = advance()) == null) {
5151	>	propagateCompletion();
5152	>	break;
5153	>	}
5154	>	if ((u = searchFunction.apply(p.key)) != null) {
5155	>	if (result.compareAndSet(null, u))
5156	>	quietlyCompleteRoot();
5157	>	break;
5158	>	}
5159	>	}
5160	>	}
5161		}
5162	<	public void clear() {
5163	<	ConcurrentHashMap.this.clear();
5162	>	}
5163	>
5164	>	@SuppressWarnings("serial")
5165	>	static final class SearchValuesTask<K,V,U>
5166	>	extends BulkTask<K,V,U> {
5167	>	final Function<? super V, ? extends U> searchFunction;
5168	>	final AtomicReference<U> result;
5169	>	SearchValuesTask
5170	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5171	>	Function<? super V, ? extends U> searchFunction,
5172	>	AtomicReference<U> result) {
5173	>	super(p, b, i, f, t);
5174	>	this.searchFunction = searchFunction; this.result = result;
5175	>	}
5176	>	public final U getRawResult() { return result.get(); }
5177	>	public final void compute() {
5178	>	final Function<? super V, ? extends U> searchFunction;
5179	>	final AtomicReference<U> result;
5180	>	if ((searchFunction = this.searchFunction) != null &&
5181	>	(result = this.result) != null) {
5182	>	for (int i = baseIndex, f, h; batch > 0 &&
5183	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5184	>	if (result.get() != null)
5185	>	return;
5186	>	addToPendingCount(1);
5187	>	new SearchValuesTask<K,V,U>
5188	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5189	>	searchFunction, result).fork();
5190	>	}
5191	>	while (result.get() == null) {
5192	>	U u;
5193	>	Node<K,V> p;
5194	>	if ((p = advance()) == null) {
5195	>	propagateCompletion();
5196	>	break;
5197	>	}
5198	>	if ((u = searchFunction.apply(p.val)) != null) {
5199	>	if (result.compareAndSet(null, u))
5200	>	quietlyCompleteRoot();
5201	>	break;
5202	>	}
5203	>	}
5204	>	}
5205		}
5206		}
5207
5208	<	private class Values extends AbstractCollection<V> {
5209	<	public Iterator<V> iterator() {
5210	<	return new ValueIterator();
5208	>	@SuppressWarnings("serial")
5209	>	static final class SearchEntriesTask<K,V,U>
5210	>	extends BulkTask<K,V,U> {
5211	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5212	>	final AtomicReference<U> result;
5213	>	SearchEntriesTask
5214	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5215	>	Function<Entry<K,V>, ? extends U> searchFunction,
5216	>	AtomicReference<U> result) {
5217	>	super(p, b, i, f, t);
5218	>	this.searchFunction = searchFunction; this.result = result;
5219	>	}
5220	>	public final U getRawResult() { return result.get(); }
5221	>	public final void compute() {
5222	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5223	>	final AtomicReference<U> result;
5224	>	if ((searchFunction = this.searchFunction) != null &&
5225	>	(result = this.result) != null) {
5226	>	for (int i = baseIndex, f, h; batch > 0 &&
5227	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5228	>	if (result.get() != null)
5229	>	return;
5230	>	addToPendingCount(1);
5231	>	new SearchEntriesTask<K,V,U>
5232	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5233	>	searchFunction, result).fork();
5234	>	}
5235	>	while (result.get() == null) {
5236	>	U u;
5237	>	Node<K,V> p;
5238	>	if ((p = advance()) == null) {
5239	>	propagateCompletion();
5240	>	break;
5241	>	}
5242	>	if ((u = searchFunction.apply(p)) != null) {
5243	>	if (result.compareAndSet(null, u))
5244	>	quietlyCompleteRoot();
5245	>	return;
5246	>	}
5247	>	}
5248	>	}
5249		}
5250	<	public int size() {
5251	<	return ConcurrentHashMap.this.size();
5250	>	}
5251	>
5252	>	@SuppressWarnings("serial")
5253	>	static final class SearchMappingsTask<K,V,U>
5254	>	extends BulkTask<K,V,U> {
5255	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5256	>	final AtomicReference<U> result;
5257	>	SearchMappingsTask
5258	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5259	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5260	>	AtomicReference<U> result) {
5261	>	super(p, b, i, f, t);
5262	>	this.searchFunction = searchFunction; this.result = result;
5263	>	}
5264	>	public final U getRawResult() { return result.get(); }
5265	>	public final void compute() {
5266	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5267	>	final AtomicReference<U> result;
5268	>	if ((searchFunction = this.searchFunction) != null &&
5269	>	(result = this.result) != null) {
5270	>	for (int i = baseIndex, f, h; batch > 0 &&
5271	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5272	>	if (result.get() != null)
5273	>	return;
5274	>	addToPendingCount(1);
5275	>	new SearchMappingsTask<K,V,U>
5276	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5277	>	searchFunction, result).fork();
5278	>	}
5279	>	while (result.get() == null) {
5280	>	U u;
5281	>	Node<K,V> p;
5282	>	if ((p = advance()) == null) {
5283	>	propagateCompletion();
5284	>	break;
5285	>	}
5286	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5287	>	if (result.compareAndSet(null, u))
5288	>	quietlyCompleteRoot();
5289	>	break;
5290	>	}
5291	>	}
5292	>	}
5293		}
5294	<	public boolean contains(Object o) {
5295	<	return ConcurrentHashMap.this.containsValue(o);
5294	>	}
5295	>
5296	>	@SuppressWarnings("serial")
5297	>	static final class ReduceKeysTask<K,V>
5298	>	extends BulkTask<K,V,K> {
5299	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5300	>	K result;
5301	>	ReduceKeysTask<K,V> rights, nextRight;
5302	>	ReduceKeysTask
5303	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5304	>	ReduceKeysTask<K,V> nextRight,
5305	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5306	>	super(p, b, i, f, t); this.nextRight = nextRight;
5307	>	this.reducer = reducer;
5308	>	}
5309	>	public final K getRawResult() { return result; }
5310	>	public final void compute() {
5311	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5312	>	if ((reducer = this.reducer) != null) {
5313	>	for (int i = baseIndex, f, h; batch > 0 &&
5314	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5315	>	addToPendingCount(1);
5316	>	(rights = new ReduceKeysTask<K,V>
5317	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5318	>	rights, reducer)).fork();
5319	>	}
5320	>	K r = null;
5321	>	for (Node<K,V> p; (p = advance()) != null; ) {
5322	>	K u = p.key;
5323	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5324	>	}
5325	>	result = r;
5326	>	CountedCompleter<?> c;
5327	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5328	>	@SuppressWarnings("unchecked")
5329	>	ReduceKeysTask<K,V>
5330	>	t = (ReduceKeysTask<K,V>)c,
5331	>	s = t.rights;
5332	>	while (s != null) {
5333	>	K tr, sr;
5334	>	if ((sr = s.result) != null)
5335	>	t.result = (((tr = t.result) == null) ? sr :
5336	>	reducer.apply(tr, sr));
5337	>	s = t.rights = s.nextRight;
5338	>	}
5339	>	}
5340	>	}
5341		}
5342	<	public void clear() {
5343	<	ConcurrentHashMap.this.clear();
5342	>	}
5343	>
5344	>	@SuppressWarnings("serial")
5345	>	static final class ReduceValuesTask<K,V>
5346	>	extends BulkTask<K,V,V> {
5347	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5348	>	V result;
5349	>	ReduceValuesTask<K,V> rights, nextRight;
5350	>	ReduceValuesTask
5351	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5352	>	ReduceValuesTask<K,V> nextRight,
5353	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5354	>	super(p, b, i, f, t); this.nextRight = nextRight;
5355	>	this.reducer = reducer;
5356	>	}
5357	>	public final V getRawResult() { return result; }
5358	>	public final void compute() {
5359	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5360	>	if ((reducer = this.reducer) != null) {
5361	>	for (int i = baseIndex, f, h; batch > 0 &&
5362	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5363	>	addToPendingCount(1);
5364	>	(rights = new ReduceValuesTask<K,V>
5365	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5366	>	rights, reducer)).fork();
5367	>	}
5368	>	V r = null;
5369	>	for (Node<K,V> p; (p = advance()) != null; ) {
5370	>	V v = p.val;
5371	>	r = (r == null) ? v : reducer.apply(r, v);
5372	>	}
5373	>	result = r;
5374	>	CountedCompleter<?> c;
5375	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5376	>	@SuppressWarnings("unchecked")
5377	>	ReduceValuesTask<K,V>
5378	>	t = (ReduceValuesTask<K,V>)c,
5379	>	s = t.rights;
5380	>	while (s != null) {
5381	>	V tr, sr;
5382	>	if ((sr = s.result) != null)
5383	>	t.result = (((tr = t.result) == null) ? sr :
5384	>	reducer.apply(tr, sr));
5385	>	s = t.rights = s.nextRight;
5386	>	}
5387	>	}
5388	>	}
5389		}
5390		}
5391
5392	<	private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
5393	<	public Iterator<Map.Entry<K,V>> iterator() {
5394	<	return new EntryIterator();
5392	>	@SuppressWarnings("serial")
5393	>	static final class ReduceEntriesTask<K,V>
5394	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5395	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5396	>	Map.Entry<K,V> result;
5397	>	ReduceEntriesTask<K,V> rights, nextRight;
5398	>	ReduceEntriesTask
5399	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5400	>	ReduceEntriesTask<K,V> nextRight,
5401	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5402	>	super(p, b, i, f, t); this.nextRight = nextRight;
5403	>	this.reducer = reducer;
5404	>	}
5405	>	public final Map.Entry<K,V> getRawResult() { return result; }
5406	>	public final void compute() {
5407	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5408	>	if ((reducer = this.reducer) != null) {
5409	>	for (int i = baseIndex, f, h; batch > 0 &&
5410	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5411	>	addToPendingCount(1);
5412	>	(rights = new ReduceEntriesTask<K,V>
5413	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5414	>	rights, reducer)).fork();
5415	>	}
5416	>	Map.Entry<K,V> r = null;
5417	>	for (Node<K,V> p; (p = advance()) != null; )
5418	>	r = (r == null) ? p : reducer.apply(r, p);
5419	>	result = r;
5420	>	CountedCompleter<?> c;
5421	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5422	>	@SuppressWarnings("unchecked")
5423	>	ReduceEntriesTask<K,V>
5424	>	t = (ReduceEntriesTask<K,V>)c,
5425	>	s = t.rights;
5426	>	while (s != null) {
5427	>	Map.Entry<K,V> tr, sr;
5428	>	if ((sr = s.result) != null)
5429	>	t.result = (((tr = t.result) == null) ? sr :
5430	>	reducer.apply(tr, sr));
5431	>	s = t.rights = s.nextRight;
5432	>	}
5433	>	}
5434	>	}
5435		}
5436	<	public boolean contains(Object o) {
5437	<	if (!(o instanceof Map.Entry))
5438	<	return false;
5439	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5440	<	V v = ConcurrentHashMap.this.get(e.getKey());
5441	<	return v != null && v.equals(e.getValue());
5436	>	}
5437	>
5438	>	@SuppressWarnings("serial")
5439	>	static final class MapReduceKeysTask<K,V,U>
5440	>	extends BulkTask<K,V,U> {
5441	>	final Function<? super K, ? extends U> transformer;
5442	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5443	>	U result;
5444	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5445	>	MapReduceKeysTask
5446	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5447	>	MapReduceKeysTask<K,V,U> nextRight,
5448	>	Function<? super K, ? extends U> transformer,
5449	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5450	>	super(p, b, i, f, t); this.nextRight = nextRight;
5451	>	this.transformer = transformer;
5452	>	this.reducer = reducer;
5453	>	}
5454	>	public final U getRawResult() { return result; }
5455	>	public final void compute() {
5456	>	final Function<? super K, ? extends U> transformer;
5457	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5458	>	if ((transformer = this.transformer) != null &&
5459	>	(reducer = this.reducer) != null) {
5460	>	for (int i = baseIndex, f, h; batch > 0 &&
5461	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5462	>	addToPendingCount(1);
5463	>	(rights = new MapReduceKeysTask<K,V,U>
5464	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5465	>	rights, transformer, reducer)).fork();
5466	>	}
5467	>	U r = null;
5468	>	for (Node<K,V> p; (p = advance()) != null; ) {
5469	>	U u;
5470	>	if ((u = transformer.apply(p.key)) != null)
5471	>	r = (r == null) ? u : reducer.apply(r, u);
5472	>	}
5473	>	result = r;
5474	>	CountedCompleter<?> c;
5475	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5476	>	@SuppressWarnings("unchecked")
5477	>	MapReduceKeysTask<K,V,U>
5478	>	t = (MapReduceKeysTask<K,V,U>)c,
5479	>	s = t.rights;
5480	>	while (s != null) {
5481	>	U tr, sr;
5482	>	if ((sr = s.result) != null)
5483	>	t.result = (((tr = t.result) == null) ? sr :
5484	>	reducer.apply(tr, sr));
5485	>	s = t.rights = s.nextRight;
5486	>	}
5487	>	}
5488	>	}
5489		}
5490	<	public boolean remove(Object o) {
5491	<	if (!(o instanceof Map.Entry))
5492	<	return false;
5493	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5494	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
5490	>	}
5491	>
5492	>	@SuppressWarnings("serial")
5493	>	static final class MapReduceValuesTask<K,V,U>
5494	>	extends BulkTask<K,V,U> {
5495	>	final Function<? super V, ? extends U> transformer;
5496	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5497	>	U result;
5498	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5499	>	MapReduceValuesTask
5500	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5501	>	MapReduceValuesTask<K,V,U> nextRight,
5502	>	Function<? super V, ? extends U> transformer,
5503	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5504	>	super(p, b, i, f, t); this.nextRight = nextRight;
5505	>	this.transformer = transformer;
5506	>	this.reducer = reducer;
5507	>	}
5508	>	public final U getRawResult() { return result; }
5509	>	public final void compute() {
5510	>	final Function<? super V, ? extends U> transformer;
5511	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5512	>	if ((transformer = this.transformer) != null &&
5513	>	(reducer = this.reducer) != null) {
5514	>	for (int i = baseIndex, f, h; batch > 0 &&
5515	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5516	>	addToPendingCount(1);
5517	>	(rights = new MapReduceValuesTask<K,V,U>
5518	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5519	>	rights, transformer, reducer)).fork();
5520	>	}
5521	>	U r = null;
5522	>	for (Node<K,V> p; (p = advance()) != null; ) {
5523	>	U u;
5524	>	if ((u = transformer.apply(p.val)) != null)
5525	>	r = (r == null) ? u : reducer.apply(r, u);
5526	>	}
5527	>	result = r;
5528	>	CountedCompleter<?> c;
5529	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5530	>	@SuppressWarnings("unchecked")
5531	>	MapReduceValuesTask<K,V,U>
5532	>	t = (MapReduceValuesTask<K,V,U>)c,
5533	>	s = t.rights;
5534	>	while (s != null) {
5535	>	U tr, sr;
5536	>	if ((sr = s.result) != null)
5537	>	t.result = (((tr = t.result) == null) ? sr :
5538	>	reducer.apply(tr, sr));
5539	>	s = t.rights = s.nextRight;
5540	>	}
5541	>	}
5542	>	}
5543		}
5544	<	public int size() {
5545	<	return ConcurrentHashMap.this.size();
5544	>	}
5545	>
5546	>	@SuppressWarnings("serial")
5547	>	static final class MapReduceEntriesTask<K,V,U>
5548	>	extends BulkTask<K,V,U> {
5549	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5550	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5551	>	U result;
5552	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5553	>	MapReduceEntriesTask
5554	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5555	>	MapReduceEntriesTask<K,V,U> nextRight,
5556	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5557	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5558	>	super(p, b, i, f, t); this.nextRight = nextRight;
5559	>	this.transformer = transformer;
5560	>	this.reducer = reducer;
5561	>	}
5562	>	public final U getRawResult() { return result; }
5563	>	public final void compute() {
5564	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5565	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5566	>	if ((transformer = this.transformer) != null &&
5567	>	(reducer = this.reducer) != null) {
5568	>	for (int i = baseIndex, f, h; batch > 0 &&
5569	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5570	>	addToPendingCount(1);
5571	>	(rights = new MapReduceEntriesTask<K,V,U>
5572	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5573	>	rights, transformer, reducer)).fork();
5574	>	}
5575	>	U r = null;
5576	>	for (Node<K,V> p; (p = advance()) != null; ) {
5577	>	U u;
5578	>	if ((u = transformer.apply(p)) != null)
5579	>	r = (r == null) ? u : reducer.apply(r, u);
5580	>	}
5581	>	result = r;
5582	>	CountedCompleter<?> c;
5583	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5584	>	@SuppressWarnings("unchecked")
5585	>	MapReduceEntriesTask<K,V,U>
5586	>	t = (MapReduceEntriesTask<K,V,U>)c,
5587	>	s = t.rights;
5588	>	while (s != null) {
5589	>	U tr, sr;
5590	>	if ((sr = s.result) != null)
5591	>	t.result = (((tr = t.result) == null) ? sr :
5592	>	reducer.apply(tr, sr));
5593	>	s = t.rights = s.nextRight;
5594	>	}
5595	>	}
5596	>	}
5597		}
5598	<	public void clear() {
5599	<	ConcurrentHashMap.this.clear();
5598	>	}
5599	>
5600	>	@SuppressWarnings("serial")
5601	>	static final class MapReduceMappingsTask<K,V,U>
5602	>	extends BulkTask<K,V,U> {
5603	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5604	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5605	>	U result;
5606	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5607	>	MapReduceMappingsTask
5608	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5609	>	MapReduceMappingsTask<K,V,U> nextRight,
5610	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5611	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5612	>	super(p, b, i, f, t); this.nextRight = nextRight;
5613	>	this.transformer = transformer;
5614	>	this.reducer = reducer;
5615	>	}
5616	>	public final U getRawResult() { return result; }
5617	>	public final void compute() {
5618	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5619	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5620	>	if ((transformer = this.transformer) != null &&
5621	>	(reducer = this.reducer) != null) {
5622	>	for (int i = baseIndex, f, h; batch > 0 &&
5623	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5624	>	addToPendingCount(1);
5625	>	(rights = new MapReduceMappingsTask<K,V,U>
5626	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5627	>	rights, transformer, reducer)).fork();
5628	>	}
5629	>	U r = null;
5630	>	for (Node<K,V> p; (p = advance()) != null; ) {
5631	>	U u;
5632	>	if ((u = transformer.apply(p.key, p.val)) != null)
5633	>	r = (r == null) ? u : reducer.apply(r, u);
5634	>	}
5635	>	result = r;
5636	>	CountedCompleter<?> c;
5637	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5638	>	@SuppressWarnings("unchecked")
5639	>	MapReduceMappingsTask<K,V,U>
5640	>	t = (MapReduceMappingsTask<K,V,U>)c,
5641	>	s = t.rights;
5642	>	while (s != null) {
5643	>	U tr, sr;
5644	>	if ((sr = s.result) != null)
5645	>	t.result = (((tr = t.result) == null) ? sr :
5646	>	reducer.apply(tr, sr));
5647	>	s = t.rights = s.nextRight;
5648	>	}
5649	>	}
5650	>	}
5651		}
5652		}
5653
5654	<	/* ---------------- Serialization Support -------------- */
5654	>	@SuppressWarnings("serial")
5655	>	static final class MapReduceKeysToDoubleTask<K,V>
5656	>	extends BulkTask<K,V,Double> {
5657	>	final ToDoubleFunction<? super K> transformer;
5658	>	final DoubleBinaryOperator reducer;
5659	>	final double basis;
5660	>	double result;
5661	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5662	>	MapReduceKeysToDoubleTask
5663	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5664	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5665	>	ToDoubleFunction<? super K> transformer,
5666	>	double basis,
5667	>	DoubleBinaryOperator reducer) {
5668	>	super(p, b, i, f, t); this.nextRight = nextRight;
5669	>	this.transformer = transformer;
5670	>	this.basis = basis; this.reducer = reducer;
5671	>	}
5672	>	public final Double getRawResult() { return result; }
5673	>	public final void compute() {
5674	>	final ToDoubleFunction<? super K> transformer;
5675	>	final DoubleBinaryOperator reducer;
5676	>	if ((transformer = this.transformer) != null &&
5677	>	(reducer = this.reducer) != null) {
5678	>	double r = this.basis;
5679	>	for (int i = baseIndex, f, h; batch > 0 &&
5680	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5681	>	addToPendingCount(1);
5682	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5683	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5684	>	rights, transformer, r, reducer)).fork();
5685	>	}
5686	>	for (Node<K,V> p; (p = advance()) != null; )
5687	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5688	>	result = r;
5689	>	CountedCompleter<?> c;
5690	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5691	>	@SuppressWarnings("unchecked")
5692	>	MapReduceKeysToDoubleTask<K,V>
5693	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5694	>	s = t.rights;
5695	>	while (s != null) {
5696	>	t.result = reducer.applyAsDouble(t.result, s.result);
5697	>	s = t.rights = s.nextRight;
5698	>	}
5699	>	}
5700	>	}
5701	>	}
5702	>	}
5703
5704	<	/**
5705	<	* Save the state of the <tt>ConcurrentHashMap</tt>
5706	<	* instance to a stream (i.e.,
5707	<	* serialize it).
5708	<	* @param s the stream
5709	<	* @serialData
5710	<	* the key (Object) and value (Object)
5711	<	* for each key-value mapping, followed by a null pair.
5712	<	* The key-value mappings are emitted in no particular order.
5713	<	*/
5714	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
5715	<	s.defaultWriteObject();
5704	>	@SuppressWarnings("serial")
5705	>	static final class MapReduceValuesToDoubleTask<K,V>
5706	>	extends BulkTask<K,V,Double> {
5707	>	final ToDoubleFunction<? super V> transformer;
5708	>	final DoubleBinaryOperator reducer;
5709	>	final double basis;
5710	>	double result;
5711	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5712	>	MapReduceValuesToDoubleTask
5713	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5714	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5715	>	ToDoubleFunction<? super V> 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 V> 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 MapReduceValuesToDoubleTask<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.val));
5738	>	result = r;
5739	>	CountedCompleter<?> c;
5740	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5741	>	@SuppressWarnings("unchecked")
5742	>	MapReduceValuesToDoubleTask<K,V>
5743	>	t = (MapReduceValuesToDoubleTask<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	<	for (int k = 0; k < segments.length; ++k) {
5755	<	Segment<K,V> seg = (Segment<K,V>)segments[k];
5756	<	seg.lock();
5757	<	try {
5758	<	HashEntry[] tab = seg.table;
5759	<	for (int i = 0; i < tab.length; ++i) {
5760	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i]; e != null; e = e.next) {
5761	<	s.writeObject(e.key);
5762	<	s.writeObject(e.value);
5754	>	@SuppressWarnings("serial")
5755	>	static final class MapReduceEntriesToDoubleTask<K,V>
5756	>	extends BulkTask<K,V,Double> {
5757	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5758	>	final DoubleBinaryOperator reducer;
5759	>	final double basis;
5760	>	double result;
5761	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5762	>	MapReduceEntriesToDoubleTask
5763	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5764	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5765	>	ToDoubleFunction<Map.Entry<K,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<Map.Entry<K,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 MapReduceEntriesToDoubleTask<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));
5788	>	result = r;
5789	>	CountedCompleter<?> c;
5790	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5791	>	@SuppressWarnings("unchecked")
5792	>	MapReduceEntriesToDoubleTask<K,V>
5793	>	t = (MapReduceEntriesToDoubleTask<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		}
1100	–	} finally {
1101	–	seg.unlock();
5800		}
5801		}
1104	–	s.writeObject(null);
1105	–	s.writeObject(null);
5802		}
5803
5804	<	/**
5805	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
5806	<	* instance from a stream (i.e.,
5807	<	* deserialize it).
5808	<	* @param s the stream
5809	<	*/
5810	<	private void readObject(java.io.ObjectInputStream s)
5811	<	throws IOException, ClassNotFoundException  {
5812	<	s.defaultReadObject();
5804	>	@SuppressWarnings("serial")
5805	>	static final class MapReduceMappingsToDoubleTask<K,V>
5806	>	extends BulkTask<K,V,Double> {
5807	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5808	>	final DoubleBinaryOperator reducer;
5809	>	final double basis;
5810	>	double result;
5811	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5812	>	MapReduceMappingsToDoubleTask
5813	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5814	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5815	>	ToDoubleBiFunction<? super K, ? super 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 ToDoubleBiFunction<? super K, ? super 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 MapReduceMappingsToDoubleTask<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.key, p.val));
5838	>	result = r;
5839	>	CountedCompleter<?> c;
5840	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5841	>	@SuppressWarnings("unchecked")
5842	>	MapReduceMappingsToDoubleTask<K,V>
5843	>	t = (MapReduceMappingsToDoubleTask<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	<	// Initialize each segment to be minimally sized, and let grow.
5855	<	for (int i = 0; i < segments.length; ++i) {
5856	<	segments[i].setTable(new HashEntry[1]);
5854	>	@SuppressWarnings("serial")
5855	>	static final class MapReduceKeysToLongTask<K,V>
5856	>	extends BulkTask<K,V,Long> {
5857	>	final ToLongFunction<? super K> transformer;
5858	>	final LongBinaryOperator reducer;
5859	>	final long basis;
5860	>	long result;
5861	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5862	>	MapReduceKeysToLongTask
5863	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5864	>	MapReduceKeysToLongTask<K,V> nextRight,
5865	>	ToLongFunction<? super K> transformer,
5866	>	long basis,
5867	>	LongBinaryOperator 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 Long getRawResult() { return result; }
5873	>	public final void compute() {
5874	>	final ToLongFunction<? super K> transformer;
5875	>	final LongBinaryOperator reducer;
5876	>	if ((transformer = this.transformer) != null &&
5877	>	(reducer = this.reducer) != null) {
5878	>	long 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 MapReduceKeysToLongTask<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.applyAsLong(r, transformer.applyAsLong(p.key));
5888	>	result = r;
5889	>	CountedCompleter<?> c;
5890	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5891	>	@SuppressWarnings("unchecked")
5892	>	MapReduceKeysToLongTask<K,V>
5893	>	t = (MapReduceKeysToLongTask<K,V>)c,
5894	>	s = t.rights;
5895	>	while (s != null) {
5896	>	t.result = reducer.applyAsLong(t.result, s.result);
5897	>	s = t.rights = s.nextRight;
5898	>	}
5899	>	}
5900	>	}
5901		}
5902	+	}
5903
5904	<	// Read the keys and values, and put the mappings in the table
5905	<	for (;;) {
5906	<	K key = (K) s.readObject();
5907	<	V value = (V) s.readObject();
5908	<	if (key == null)
5909	<	break;
5910	<	put(key, value);
5904	>	@SuppressWarnings("serial")
5905	>	static final class MapReduceValuesToLongTask<K,V>
5906	>	extends BulkTask<K,V,Long> {
5907	>	final ToLongFunction<? super V> transformer;
5908	>	final LongBinaryOperator reducer;
5909	>	final long basis;
5910	>	long result;
5911	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5912	>	MapReduceValuesToLongTask
5913	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5914	>	MapReduceValuesToLongTask<K,V> nextRight,
5915	>	ToLongFunction<? super V> 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 V> 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 MapReduceValuesToLongTask<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.val));
5938	>	result = r;
5939	>	CountedCompleter<?> c;
5940	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5941	>	@SuppressWarnings("unchecked")
5942	>	MapReduceValuesToLongTask<K,V>
5943	>	t = (MapReduceValuesToLongTask<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 MapReduceEntriesToLongTask<K,V>
5956	>	extends BulkTask<K,V,Long> {
5957	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5958	>	final LongBinaryOperator reducer;
5959	>	final long basis;
5960	>	long result;
5961	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5962	>	MapReduceEntriesToLongTask
5963	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5964	>	MapReduceEntriesToLongTask<K,V> nextRight,
5965	>	ToLongFunction<Map.Entry<K,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<Map.Entry<K,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 MapReduceEntriesToLongTask<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));
5988	>	result = r;
5989	>	CountedCompleter<?> c;
5990	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5991	>	@SuppressWarnings("unchecked")
5992	>	MapReduceEntriesToLongTask<K,V>
5993	>	t = (MapReduceEntriesToLongTask<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 MapReduceMappingsToLongTask<K,V>
6006	>	extends BulkTask<K,V,Long> {
6007	>	final ToLongBiFunction<? super K, ? super V> transformer;
6008	>	final LongBinaryOperator reducer;
6009	>	final long basis;
6010	>	long result;
6011	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6012	>	MapReduceMappingsToLongTask
6013	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6014	>	MapReduceMappingsToLongTask<K,V> nextRight,
6015	>	ToLongBiFunction<? super K, ? super 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 ToLongBiFunction<? super K, ? super 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 MapReduceMappingsToLongTask<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.key, p.val));
6038	>	result = r;
6039	>	CountedCompleter<?> c;
6040	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6041	>	@SuppressWarnings("unchecked")
6042	>	MapReduceMappingsToLongTask<K,V>
6043	>	t = (MapReduceMappingsToLongTask<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 MapReduceKeysToIntTask<K,V>
6056	>	extends BulkTask<K,V,Integer> {
6057	>	final ToIntFunction<? super K> transformer;
6058	>	final IntBinaryOperator reducer;
6059	>	final int basis;
6060	>	int result;
6061	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6062	>	MapReduceKeysToIntTask
6063	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6064	>	MapReduceKeysToIntTask<K,V> nextRight,
6065	>	ToIntFunction<? super K> transformer,
6066	>	int basis,
6067	>	IntBinaryOperator 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 Integer getRawResult() { return result; }
6073	>	public final void compute() {
6074	>	final ToIntFunction<? super K> transformer;
6075	>	final IntBinaryOperator reducer;
6076	>	if ((transformer = this.transformer) != null &&
6077	>	(reducer = this.reducer) != null) {
6078	>	int 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 MapReduceKeysToIntTask<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.applyAsInt(r, transformer.applyAsInt(p.key));
6088	>	result = r;
6089	>	CountedCompleter<?> c;
6090	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6091	>	@SuppressWarnings("unchecked")
6092	>	MapReduceKeysToIntTask<K,V>
6093	>	t = (MapReduceKeysToIntTask<K,V>)c,
6094	>	s = t.rights;
6095	>	while (s != null) {
6096	>	t.result = reducer.applyAsInt(t.result, s.result);
6097	>	s = t.rights = s.nextRight;
6098	>	}
6099	>	}
6100	>	}
6101	>	}
6102	>	}
6103	>
6104	>	@SuppressWarnings("serial")
6105	>	static final class MapReduceValuesToIntTask<K,V>
6106	>	extends BulkTask<K,V,Integer> {
6107	>	final ToIntFunction<? super V> transformer;
6108	>	final IntBinaryOperator reducer;
6109	>	final int basis;
6110	>	int result;
6111	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6112	>	MapReduceValuesToIntTask
6113	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6114	>	MapReduceValuesToIntTask<K,V> nextRight,
6115	>	ToIntFunction<? super V> 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 V> 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 MapReduceValuesToIntTask<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.val));
6138	>	result = r;
6139	>	CountedCompleter<?> c;
6140	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6141	>	@SuppressWarnings("unchecked")
6142	>	MapReduceValuesToIntTask<K,V>
6143	>	t = (MapReduceValuesToIntTask<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 MapReduceEntriesToIntTask<K,V>
6156	>	extends BulkTask<K,V,Integer> {
6157	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6158	>	final IntBinaryOperator reducer;
6159	>	final int basis;
6160	>	int result;
6161	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6162	>	MapReduceEntriesToIntTask
6163	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6164	>	MapReduceEntriesToIntTask<K,V> nextRight,
6165	>	ToIntFunction<Map.Entry<K,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<Map.Entry<K,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 MapReduceEntriesToIntTask<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));
6188	>	result = r;
6189	>	CountedCompleter<?> c;
6190	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6191	>	@SuppressWarnings("unchecked")
6192	>	MapReduceEntriesToIntTask<K,V>
6193	>	t = (MapReduceEntriesToIntTask<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		}
1132	–	}
6203
6204	+	@SuppressWarnings("serial")
6205	+	static final class MapReduceMappingsToIntTask<K,V>
6206	+	extends BulkTask<K,V,Integer> {
6207	+	final ToIntBiFunction<? super K, ? super V> transformer;
6208	+	final IntBinaryOperator reducer;
6209	+	final int basis;
6210	+	int result;
6211	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6212	+	MapReduceMappingsToIntTask
6213	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6214	+	MapReduceMappingsToIntTask<K,V> nextRight,
6215	+	ToIntBiFunction<? super K, ? super 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 ToIntBiFunction<? super K, ? super 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 MapReduceMappingsToIntTask<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.key, p.val));
6238	+	result = r;
6239	+	CountedCompleter<?> c;
6240	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6241	+	@SuppressWarnings("unchecked")
6242	+	MapReduceMappingsToIntTask<K,V>
6243	+	t = (MapReduceMappingsToIntTask<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	+	// Unsafe mechanics
6255	+	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
6256	+	private static final long SIZECTL;
6257	+	private static final long TRANSFERINDEX;
6258	+	private static final long BASECOUNT;
6259	+	private static final long CELLSBUSY;
6260	+	private static final long CELLVALUE;
6261	+	private static final int ABASE;
6262	+	private static final int ASHIFT;
6263	+
6264	+	static {
6265	+	try {
6266	+	SIZECTL = U.objectFieldOffset
6267	+	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6268	+	TRANSFERINDEX = U.objectFieldOffset
6269	+	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6270	+	BASECOUNT = U.objectFieldOffset
6271	+	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6272	+	CELLSBUSY = U.objectFieldOffset
6273	+	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6274	+
6275	+	CELLVALUE = U.objectFieldOffset
6276	+	(CounterCell.class.getDeclaredField("value"));
6277	+
6278	+	ABASE = U.arrayBaseOffset(Node[].class);
6279	+	int scale = U.arrayIndexScale(Node[].class);
6280	+	if ((scale & (scale - 1)) != 0)
6281	+	throw new Error("array index scale not a power of two");
6282	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6283	+	} catch (ReflectiveOperationException e) {
6284	+	throw new Error(e);
6285	+	}
6286	+	}
6287	+	}

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