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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.110 by jsr166, Wed Apr 27 14:06:30 2011 UTC vs.
Revision 1.187 by jsr166, Fri Feb 15 22:27:11 2013 UTC

#	Line 5 | Line 5
5		*/
6
7		package java.util.concurrent;
8	<	import java.util.concurrent.locks.*;
9	<	import java.util.*;
8	>	import java.util.concurrent.ForkJoinPool;
9	>	import java.util.concurrent.CountedCompleter;
10	>	import java.util.function.*;
11	>	import java.util.Spliterator;
12	>	import java.util.stream.Stream;
13	>	import java.util.stream.Streams;
14	>
15	>	import java.util.Comparator;
16	>	import java.util.Arrays;
17	>	import java.util.Map;
18	>	import java.util.Set;
19	>	import java.util.Collection;
20	>	import java.util.AbstractMap;
21	>	import java.util.AbstractSet;
22	>	import java.util.AbstractCollection;
23	>	import java.util.Hashtable;
24	>	import java.util.HashMap;
25	>	import java.util.Iterator;
26	>	import java.util.Enumeration;
27	>	import java.util.ConcurrentModificationException;
28	>	import java.util.NoSuchElementException;
29	>	import java.util.concurrent.ConcurrentMap;
30	>	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
31	>	import java.util.concurrent.atomic.AtomicInteger;
32	>	import java.util.concurrent.atomic.AtomicReference;
33		import java.io.Serializable;
11	–	import java.io.IOException;
12	–	import java.io.ObjectInputStream;
13	–	import java.io.ObjectOutputStream;
34
35		/**
36		* A hash table supporting full concurrency of retrievals and
37	<	* adjustable expected concurrency for updates. This class obeys the
37	>	* high expected concurrency for updates. This class obeys the
38		* same functional specification as {@link java.util.Hashtable}, and
39		* includes versions of methods corresponding to each method of
40	<	* <tt>Hashtable</tt>. However, even though all operations are
40	>	* {@code Hashtable}. However, even though all operations are
41		* thread-safe, retrieval operations do <em>not</em> entail locking,
42		* and there is <em>not</em> any support for locking the entire table
43		* in a way that prevents all access.  This class is fully
44	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
44	>	* interoperable with {@code Hashtable} in programs that rely on its
45		* thread safety but not on its synchronization details.
46		*
47	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
48	<	* block, so may overlap with update operations (including
49	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
50	<	* of the most recently <em>completed</em> update operations holding
51	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
52	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
53	<	* removal of only some entries.  Similarly, Iterators and
54	<	* Enumerations return elements reflecting the state of the hash table
55	<	* at some point at or since the creation of the iterator/enumeration.
56	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
57	<	* However, iterators are designed to be used by only one thread at a time.
58	<	*
59	<	* <p> The allowed concurrency among update operations is guided by
60	<	* the optional <tt>concurrencyLevel</tt> constructor argument
61	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
62	<	* table is internally partitioned to try to permit the indicated
63	<	* number of concurrent updates without contention. Because placement
64	<	* in hash tables is essentially random, the actual concurrency will
65	<	* vary.  Ideally, you should choose a value to accommodate as many
66	<	* threads as will ever concurrently modify the table. Using a
67	<	* significantly higher value than you need can waste space and time,
68	<	* and a significantly lower value can lead to thread contention. But
69	<	* overestimates and underestimates within an order of magnitude do
70	<	* not usually have much noticeable impact. A value of one is
71	<	* appropriate when it is known that only one thread will modify and
72	<	* all others will only read. Also, resizing this or any other kind of
73	<	* hash table is a relatively slow operation, so, when possible, it is
74	<	* a good idea to provide estimates of expected table sizes in
75	<	* constructors.
47	>	* <p>Retrieval operations (including {@code get}) generally do not
48	>	* block, so may overlap with update operations (including {@code put}
49	>	* and {@code remove}). Retrievals reflect the results of the most
50	>	* recently <em>completed</em> update operations holding upon their
51	>	* onset. (More formally, an update operation for a given key bears a
52	>	* <em>happens-before</em> relation with any (non-null) retrieval for
53	>	* that key reporting the updated value.)  For aggregate operations
54	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
55	>	* reflect insertion or removal of only some entries.  Similarly,
56	>	* Iterators and Enumerations return elements reflecting the state of
57	>	* the hash table at some point at or since the creation of the
58	>	* iterator/enumeration.  They do <em>not</em> throw {@link
59	>	* ConcurrentModificationException}.  However, iterators are designed
60	>	* to be used by only one thread at a time.  Bear in mind that the
61	>	* results of aggregate status methods including {@code size}, {@code
62	>	* isEmpty}, and {@code containsValue} are typically useful only when
63	>	* a map is not undergoing concurrent updates in other threads.
64	>	* Otherwise the results of these methods reflect transient states
65	>	* that may be adequate for monitoring or estimation purposes, but not
66	>	* for program control.
67	>	*
68	>	* <p>The table is dynamically expanded when there are too many
69	>	* collisions (i.e., keys that have distinct hash codes but fall into
70	>	* the same slot modulo the table size), with the expected average
71	>	* effect of maintaining roughly two bins per mapping (corresponding
72	>	* to a 0.75 load factor threshold for resizing). There may be much
73	>	* variance around this average as mappings are added and removed, but
74	>	* overall, this maintains a commonly accepted time/space tradeoff for
75	>	* hash tables.  However, resizing this or any other kind of hash
76	>	* table may be a relatively slow operation. When possible, it is a
77	>	* good idea to provide a size estimate as an optional {@code
78	>	* initialCapacity} constructor argument. An additional optional
79	>	* {@code loadFactor} constructor argument provides a further means of
80	>	* customizing initial table capacity by specifying the table density
81	>	* to be used in calculating the amount of space to allocate for the
82	>	* given number of elements.  Also, for compatibility with previous
83	>	* versions of this class, constructors may optionally specify an
84	>	* expected {@code concurrencyLevel} as an additional hint for
85	>	* internal sizing.  Note that using many keys with exactly the same
86	>	* {@code hashCode()} is a sure way to slow down performance of any
87	>	* hash table.
88	>	*
89	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
90	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
91	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
92	>	* mapped values are (perhaps transiently) not used or all take the
93	>	* same mapping value.
94	>	*
95	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
96	>	* form of histogram or multiset) by using {@link
97	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
98	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
99	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
100	>	* {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();}
101		*
102		* <p>This class and its views and iterators implement all of the
103		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
104		* interfaces.
105		*
106	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
107	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
106	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
107	>	* does <em>not</em> allow {@code null} to be used as a key or value.
108	>	*
109	>	* <p>ConcurrentHashMaps support sequential and parallel operations
110	>	* bulk operations. (Parallel forms use the {@link
111	>	* ForkJoinPool#commonPool()}). Tasks that may be used in other
112	>	* contexts are available in class {@link ForkJoinTasks}. These
113	>	* operations are designed to be safely, and often sensibly, applied
114	>	* even with maps that are being concurrently updated by other
115	>	* threads; for example, when computing a snapshot summary of the
116	>	* values in a shared registry.  There are three kinds of operation,
117	>	* each with four forms, accepting functions with Keys, Values,
118	>	* Entries, and (Key, Value) arguments and/or return values. Because
119	>	* the elements of a ConcurrentHashMap are not ordered in any
120	>	* particular way, and may be processed in different orders in
121	>	* different parallel executions, the correctness of supplied
122	>	* functions should not depend on any ordering, or on any other
123	>	* objects or values that may transiently change while computation is
124	>	* in progress; and except for forEach actions, should ideally be
125	>	* side-effect-free.
126	>	*
127	>	* <ul>
128	>	* <li> forEach: Perform a given action on each element.
129	>	* A variant form applies a given transformation on each element
130	>	* before performing the action.</li>
131	>	*
132	>	* <li> search: Return the first available non-null result of
133	>	* applying a given function on each element; skipping further
134	>	* search when a result is found.</li>
135	>	*
136	>	* <li> reduce: Accumulate each element.  The supplied reduction
137	>	* function cannot rely on ordering (more formally, it should be
138	>	* both associative and commutative).  There are five variants:
139	>	*
140	>	* <ul>
141	>	*
142	>	* <li> Plain reductions. (There is not a form of this method for
143	>	* (key, value) function arguments since there is no corresponding
144	>	* return type.)</li>
145	>	*
146	>	* <li> Mapped reductions that accumulate the results of a given
147	>	* function applied to each element.</li>
148	>	*
149	>	* <li> Reductions to scalar doubles, longs, and ints, using a
150	>	* given basis value.</li>
151	>	*
152	>	* </ul>
153	>	* </li>
154	>	* </ul>
155	>	*
156	>	* <p>The concurrency properties of bulk operations follow
157	>	* from those of ConcurrentHashMap: Any non-null result returned
158	>	* from {@code get(key)} and related access methods bears a
159	>	* happens-before relation with the associated insertion or
160	>	* update.  The result of any bulk operation reflects the
161	>	* composition of these per-element relations (but is not
162	>	* necessarily atomic with respect to the map as a whole unless it
163	>	* is somehow known to be quiescent).  Conversely, because keys
164	>	* and values in the map are never null, null serves as a reliable
165	>	* atomic indicator of the current lack of any result.  To
166	>	* maintain this property, null serves as an implicit basis for
167	>	* all non-scalar reduction operations. For the double, long, and
168	>	* int versions, the basis should be one that, when combined with
169	>	* any other value, returns that other value (more formally, it
170	>	* should be the identity element for the reduction). Most common
171	>	* reductions have these properties; for example, computing a sum
172	>	* with basis 0 or a minimum with basis MAX_VALUE.
173	>	*
174	>	* <p>Search and transformation functions provided as arguments
175	>	* should similarly return null to indicate the lack of any result
176	>	* (in which case it is not used). In the case of mapped
177	>	* reductions, this also enables transformations to serve as
178	>	* filters, returning null (or, in the case of primitive
179	>	* specializations, the identity basis) if the element should not
180	>	* be combined. You can create compound transformations and
181	>	* filterings by composing them yourself under this "null means
182	>	* there is nothing there now" rule before using them in search or
183	>	* reduce operations.
184	>	*
185	>	* <p>Methods accepting and/or returning Entry arguments maintain
186	>	* key-value associations. They may be useful for example when
187	>	* finding the key for the greatest value. Note that "plain" Entry
188	>	* arguments can be supplied using {@code new
189	>	* AbstractMap.SimpleEntry(k,v)}.
190	>	*
191	>	* <p>Bulk operations may complete abruptly, throwing an
192	>	* exception encountered in the application of a supplied
193	>	* function. Bear in mind when handling such exceptions that other
194	>	* concurrently executing functions could also have thrown
195	>	* exceptions, or would have done so if the first exception had
196	>	* not occurred.
197	>	*
198	>	* <p>Speedups for parallel compared to sequential forms are common
199	>	* but not guaranteed.  Parallel operations involving brief functions
200	>	* on small maps may execute more slowly than sequential forms if the
201	>	* underlying work to parallelize the computation is more expensive
202	>	* than the computation itself.  Similarly, parallelization may not
203	>	* lead to much actual parallelism if all processors are busy
204	>	* performing unrelated tasks.
205	>	*
206	>	* <p>All arguments to all task methods must be non-null.
207		*
208		* <p>This class is a member of the
209		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 70 | Line 214 | import java.io.ObjectOutputStream;
214		* @param <K> the type of keys maintained by this map
215		* @param <V> the type of mapped values
216		*/
217	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
218	<	implements ConcurrentMap<K, V>, Serializable {
217	>	public class ConcurrentHashMap<K,V>
218	>	implements ConcurrentMap<K,V>, Serializable {
219		private static final long serialVersionUID = 7249069246763182397L;
220
221		/*
222	<	* The basic strategy is to subdivide the table among Segments,
223	<	* each of which itself is a concurrently readable hash table.  To
224	<	* reduce footprint, all but one segments are constructed only
225	<	* when first needed (see ensureSegment). To maintain visibility
226	<	* in the presence of lazy construction, accesses to segments as
227	<	* well as elements of segment's table must use volatile access,
228	<	* which is done via Unsafe within methods segmentAt etc
229	<	* below. These provide the functionality of AtomicReferenceArrays
230	<	* but reduce the levels of indirection. Additionally,
231	<	* volatile-writes of table elements and entry "next" fields
232	<	* within locked operations use the cheaper "lazySet" forms of
233	<	* writes (via putOrderedObject) because these writes are always
234	<	* followed by lock releases that maintain sequential consistency
235	<	* of table updates.
236	<	*
237	<	* Historical note: The previous version of this class relied
238	<	* heavily on "final" fields, which avoided some volatile reads at
239	<	* the expense of a large initial footprint.  Some remnants of
240	<	* that design (including forced construction of segment 0) exist
241	<	* to ensure serialization compatibility.
222	>	* Overview:
223	>	*
224	>	* The primary design goal of this hash table is to maintain
225	>	* concurrent readability (typically method get(), but also
226	>	* iterators and related methods) while minimizing update
227	>	* contention. Secondary goals are to keep space consumption about
228	>	* the same or better than java.util.HashMap, and to support high
229	>	* initial insertion rates on an empty table by many threads.
230	>	*
231	>	* Each key-value mapping is held in a Node.  Because Node key
232	>	* fields can contain special values, they are defined using plain
233	>	* Object types (not type "K"). This leads to a lot of explicit
234	>	* casting (and many explicit warning suppressions to tell
235	>	* compilers not to complain about it). It also allows some of the
236	>	* public methods to be factored into a smaller number of internal
237	>	* methods (although sadly not so for the five variants of
238	>	* put-related operations). The validation-based approach
239	>	* explained below leads to a lot of code sprawl because
240	>	* retry-control precludes factoring into smaller methods.
241	>	*
242	>	* The table is lazily initialized to a power-of-two size upon the
243	>	* first insertion.  Each bin in the table normally contains a
244	>	* list of Nodes (most often, the list has only zero or one Node).
245	>	* Table accesses require volatile/atomic reads, writes, and
246	>	* CASes.  Because there is no other way to arrange this without
247	>	* adding further indirections, we use intrinsics
248	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
249	>	* are always accurately traversable under volatile reads, so long
250	>	* as lookups check hash code and non-nullness of value before
251	>	* checking key equality.
252	>	*
253	>	* We use the top (sign) bit of Node hash fields for control
254	>	* purposes -- it is available anyway because of addressing
255	>	* constraints.  Nodes with negative hash fields are forwarding
256	>	* nodes to either TreeBins or resized tables.  The lower 31 bits
257	>	* of each normal Node's hash field contain a transformation of
258	>	* the key's hash code.
259	>	*
260	>	* Insertion (via put or its variants) of the first node in an
261	>	* empty bin is performed by just CASing it to the bin.  This is
262	>	* by far the most common case for put operations under most
263	>	* key/hash distributions.  Other update operations (insert,
264	>	* delete, and replace) require locks.  We do not want to waste
265	>	* the space required to associate a distinct lock object with
266	>	* each bin, so instead use the first node of a bin list itself as
267	>	* a lock. Locking support for these locks relies on builtin
268	>	* "synchronized" monitors.
269	>	*
270	>	* Using the first node of a list as a lock does not by itself
271	>	* suffice though: When a node is locked, any update must first
272	>	* validate that it is still the first node after locking it, and
273	>	* retry if not. Because new nodes are always appended to lists,
274	>	* once a node is first in a bin, it remains first until deleted
275	>	* or the bin becomes invalidated (upon resizing).  However,
276	>	* operations that only conditionally update may inspect nodes
277	>	* until the point of update. This is a converse of sorts to the
278	>	* lazy locking technique described by Herlihy & Shavit.
279	>	*
280	>	* The main disadvantage of per-bin locks is that other update
281	>	* operations on other nodes in a bin list protected by the same
282	>	* lock can stall, for example when user equals() or mapping
283	>	* functions take a long time.  However, statistically, under
284	>	* random hash codes, this is not a common problem.  Ideally, the
285	>	* frequency of nodes in bins follows a Poisson distribution
286	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
287	>	* parameter of about 0.5 on average, given the resizing threshold
288	>	* of 0.75, although with a large variance because of resizing
289	>	* granularity. Ignoring variance, the expected occurrences of
290	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
291	>	* first values are:
292	>	*
293	>	* 0:    0.60653066
294	>	* 1:    0.30326533
295	>	* 2:    0.07581633
296	>	* 3:    0.01263606
297	>	* 4:    0.00157952
298	>	* 5:    0.00015795
299	>	* 6:    0.00001316
300	>	* 7:    0.00000094
301	>	* 8:    0.00000006
302	>	* more: less than 1 in ten million
303	>	*
304	>	* Lock contention probability for two threads accessing distinct
305	>	* elements is roughly 1 / (8 * #elements) under random hashes.
306	>	*
307	>	* Actual hash code distributions encountered in practice
308	>	* sometimes deviate significantly from uniform randomness.  This
309	>	* includes the case when N > (1<<30), so some keys MUST collide.
310	>	* Similarly for dumb or hostile usages in which multiple keys are
311	>	* designed to have identical hash codes. Also, although we guard
312	>	* against the worst effects of this (see method spread), sets of
313	>	* hashes may differ only in bits that do not impact their bin
314	>	* index for a given power-of-two mask.  So we use a secondary
315	>	* strategy that applies when the number of nodes in a bin exceeds
316	>	* a threshold, and at least one of the keys implements
317	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
318	>	* (a specialized form of red-black trees), bounding search time
319	>	* to O(log N).  Each search step in a TreeBin is around twice as
320	>	* slow as in a regular list, but given that N cannot exceed
321	>	* (1<<64) (before running out of addresses) this bounds search
322	>	* steps, lock hold times, etc, to reasonable constants (roughly
323	>	* 100 nodes inspected per operation worst case) so long as keys
324	>	* are Comparable (which is very common -- String, Long, etc).
325	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
326	>	* traversal pointers as regular nodes, so can be traversed in
327	>	* iterators in the same way.
328	>	*
329	>	* The table is resized when occupancy exceeds a percentage
330	>	* threshold (nominally, 0.75, but see below).  Any thread
331	>	* noticing an overfull bin may assist in resizing after the
332	>	* initiating thread allocates and sets up the replacement
333	>	* array. However, rather than stalling, these other threads may
334	>	* proceed with insertions etc.  The use of TreeBins shields us
335	>	* from the worst case effects of overfilling while resizes are in
336	>	* progress.  Resizing proceeds by transferring bins, one by one,
337	>	* from the table to the next table. To enable concurrency, the
338	>	* next table must be (incrementally) prefilled with place-holders
339	>	* serving as reverse forwarders to the old table.  Because we are
340	>	* using power-of-two expansion, the elements from each bin must
341	>	* either stay at same index, or move with a power of two
342	>	* offset. We eliminate unnecessary node creation by catching
343	>	* cases where old nodes can be reused because their next fields
344	>	* won't change.  On average, only about one-sixth of them need
345	>	* cloning when a table doubles. The nodes they replace will be
346	>	* garbage collectable as soon as they are no longer referenced by
347	>	* any reader thread that may be in the midst of concurrently
348	>	* traversing table.  Upon transfer, the old table bin contains
349	>	* only a special forwarding node (with hash field "MOVED") that
350	>	* contains the next table as its key. On encountering a
351	>	* forwarding node, access and update operations restart, using
352	>	* the new table.
353	>	*
354	>	* Each bin transfer requires its bin lock, which can stall
355	>	* waiting for locks while resizing. However, because other
356	>	* threads can join in and help resize rather than contend for
357	>	* locks, average aggregate waits become shorter as resizing
358	>	* progresses.  The transfer operation must also ensure that all
359	>	* accessible bins in both the old and new table are usable by any
360	>	* traversal.  This is arranged by proceeding from the last bin
361	>	* (table.length - 1) up towards the first.  Upon seeing a
362	>	* forwarding node, traversals (see class Traverser) arrange to
363	>	* move to the new table without revisiting nodes.  However, to
364	>	* ensure that no intervening nodes are skipped, bin splitting can
365	>	* only begin after the associated reverse-forwarders are in
366	>	* place.
367	>	*
368	>	* The traversal scheme also applies to partial traversals of
369	>	* ranges of bins (via an alternate Traverser constructor)
370	>	* to support partitioned aggregate operations.  Also, read-only
371	>	* operations give up if ever forwarded to a null table, which
372	>	* provides support for shutdown-style clearing, which is also not
373	>	* currently implemented.
374	>	*
375	>	* Lazy table initialization minimizes footprint until first use,
376	>	* and also avoids resizings when the first operation is from a
377	>	* putAll, constructor with map argument, or deserialization.
378	>	* These cases attempt to override the initial capacity settings,
379	>	* but harmlessly fail to take effect in cases of races.
380	>	*
381	>	* The element count is maintained using a specialization of
382	>	* LongAdder. We need to incorporate a specialization rather than
383	>	* just use a LongAdder in order to access implicit
384	>	* contention-sensing that leads to creation of multiple
385	>	* Cells.  The counter mechanics avoid contention on
386	>	* updates but can encounter cache thrashing if read too
387	>	* frequently during concurrent access. To avoid reading so often,
388	>	* resizing under contention is attempted only upon adding to a
389	>	* bin already holding two or more nodes. Under uniform hash
390	>	* distributions, the probability of this occurring at threshold
391	>	* is around 13%, meaning that only about 1 in 8 puts check
392	>	* threshold (and after resizing, many fewer do so). The bulk
393	>	* putAll operation further reduces contention by only committing
394	>	* count updates upon these size checks.
395	>	*
396	>	* Maintaining API and serialization compatibility with previous
397	>	* versions of this class introduces several oddities. Mainly: We
398	>	* leave untouched but unused constructor arguments refering to
399	>	* concurrencyLevel. We accept a loadFactor constructor argument,
400	>	* but apply it only to initial table capacity (which is the only
401	>	* time that we can guarantee to honor it.) We also declare an
402	>	* unused "Segment" class that is instantiated in minimal form
403	>	* only when serializing.
404		*/
405
406		/* ---------------- Constants -------------- */
407
408		/**
409	<	* The default initial capacity for this table,
410	<	* used when not otherwise specified in a constructor.
409	>	* The largest possible table capacity.  This value must be
410	>	* exactly 1<<30 to stay within Java array allocation and indexing
411	>	* bounds for power of two table sizes, and is further required
412	>	* because the top two bits of 32bit hash fields are used for
413	>	* control purposes.
414		*/
415	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
415	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
416
417		/**
418	<	* The default load factor for this table, used when not
419	<	* otherwise specified in a constructor.
418	>	* The default initial table capacity.  Must be a power of 2
419	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
420		*/
421	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
421	>	private static final int DEFAULT_CAPACITY = 16;
422
423		/**
424	<	* The default concurrency level for this table, used when not
425	<	* otherwise specified in a constructor.
424	>	* The largest possible (non-power of two) array size.
425	>	* Needed by toArray and related methods.
426		*/
427	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
427	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
428
429		/**
430	<	* The maximum capacity, used if a higher value is implicitly
431	<	* specified by either of the constructors with arguments.  MUST
123	<	* be a power of two <= 1<<30 to ensure that entries are indexable
124	<	* using ints.
430	>	* The default concurrency level for this table. Unused but
431	>	* defined for compatibility with previous versions of this class.
432		*/
433	<	static final int MAXIMUM_CAPACITY = 1 << 30;
433	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
434
435		/**
436	<	* The minimum capacity for per-segment tables.  Must be a power
437	<	* of two, at least two to avoid immediate resizing on next use
438	<	* after lazy construction.
436	>	* The load factor for this table. Overrides of this value in
437	>	* constructors affect only the initial table capacity.  The
438	>	* actual floating point value isn't normally used -- it is
439	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
440	>	* the associated resizing threshold.
441		*/
442	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
442	>	private static final float LOAD_FACTOR = 0.75f;
443
444		/**
445	<	* The maximum number of segments to allow; used to bound
446	<	* constructor arguments. Must be power of two less than 1 << 24.
445	>	* The bin count threshold for using a tree rather than list for a
446	>	* bin.  The value reflects the approximate break-even point for
447	>	* using tree-based operations.
448		*/
449	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
449	>	private static final int TREE_THRESHOLD = 8;
450
451		/**
452	<	* Number of unsynchronized retries in size and containsValue
453	<	* methods before resorting to locking. This is used to avoid
454	<	* unbounded retries if tables undergo continuous modification
455	<	* which would make it impossible to obtain an accurate result.
452	>	* Minimum number of rebinnings per transfer step. Ranges are
453	>	* subdivided to allow multiple resizer threads.  This value
454	>	* serves as a lower bound to avoid resizers encountering
455	>	* excessive memory contention.  The value should be at least
456	>	* DEFAULT_CAPACITY.
457		*/
458	<	static final int RETRIES_BEFORE_LOCK = 2;
458	>	private static final int MIN_TRANSFER_STRIDE = 16;
459	>
460	>	/*
461	>	* Encodings for Node hash fields. See above for explanation.
462	>	*/
463	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
464	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
465	>
466	>	/** Number of CPUS, to place bounds on some sizings */
467	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
468	>
469	>	/* ---------------- Counters -------------- */
470	>
471	>	// Adapted from LongAdder and Striped64.
472	>	// See their internal docs for explanation.
473	>
474	>	// A padded cell for distributing counts
475	>	static final class Cell {
476	>	volatile long p0, p1, p2, p3, p4, p5, p6;
477	>	volatile long value;
478	>	volatile long q0, q1, q2, q3, q4, q5, q6;
479	>	Cell(long x) { value = x; }
480	>	}
481
482		/* ---------------- Fields -------------- */
483
484		/**
485	<	* Mask value for indexing into segments. The upper bits of a
486	<	* key's hash code are used to choose the segment.
485	>	* The array of bins. Lazily initialized upon first insertion.
486	>	* Size is always a power of two. Accessed directly by iterators.
487		*/
488	<	final int segmentMask;
488	>	transient volatile Node<V>[] table;
489
490		/**
491	<	* Shift value for indexing within segments.
491	>	* The next table to use; non-null only while resizing.
492		*/
493	<	final int segmentShift;
493	>	private transient volatile Node<V>[] nextTable;
494
495		/**
496	<	* The segments, each of which is a specialized hash table.
496	>	* Base counter value, used mainly when there is no contention,
497	>	* but also as a fallback during table initialization
498	>	* races. Updated via CAS.
499		*/
500	<	final Segment<K,V>[] segments;
500	>	private transient volatile long baseCount;
501
502	<	transient Set<K> keySet;
503	<	transient Set<Map.Entry<K,V>> entrySet;
504	<	transient Collection<V> values;
502	>	/**
503	>	* Table initialization and resizing control.  When negative, the
504	>	* table is being initialized or resized: -1 for initialization,
505	>	* else -(1 + the number of active resizing threads).  Otherwise,
506	>	* when table is null, holds the initial table size to use upon
507	>	* creation, or 0 for default. After initialization, holds the
508	>	* next element count value upon which to resize the table.
509	>	*/
510	>	private transient volatile int sizeCtl;
511	>
512	>	/**
513	>	* The next table index (plus one) to split while resizing.
514	>	*/
515	>	private transient volatile int transferIndex;
516
517		/**
518	<	* ConcurrentHashMap list entry. Note that this is never exported
173	<	* out as a user-visible Map.Entry.
518	>	* The least available table index to split while resizing.
519		*/
520	<	static final class HashEntry<K,V> {
520	>	private transient volatile int transferOrigin;
521	>
522	>	/**
523	>	* Spinlock (locked via CAS) used when resizing and/or creating Cells.
524	>	*/
525	>	private transient volatile int cellsBusy;
526	>
527	>	/**
528	>	* Table of counter cells. When non-null, size is a power of 2.
529	>	*/
530	>	private transient volatile Cell[] counterCells;
531	>
532	>	// views
533	>	private transient KeySetView<K,V> keySet;
534	>	private transient ValuesView<K,V> values;
535	>	private transient EntrySetView<K,V> entrySet;
536	>
537	>	/** For serialization compatibility. Null unless serialized; see below */
538	>	private Segment<K,V>[] segments;
539	>
540	>	/* ---------------- Table element access -------------- */
541	>
542	>	/*
543	>	* Volatile access methods are used for table elements as well as
544	>	* elements of in-progress next table while resizing.  Uses are
545	>	* null checked by callers, and implicitly bounds-checked, relying
546	>	* on the invariants that tab arrays have non-zero size, and all
547	>	* indices are masked with (tab.length - 1) which is never
548	>	* negative and always less than length. Note that, to be correct
549	>	* wrt arbitrary concurrency errors by users, bounds checks must
550	>	* operate on local variables, which accounts for some odd-looking
551	>	* inline assignments below.
552	>	*/
553	>
554	>	@SuppressWarnings("unchecked") static final <V> Node<V> tabAt
555	>	(Node<V>[] tab, int i) { // used by Traverser
556	>	return (Node<V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
557	>	}
558	>
559	>	private static final <V> boolean casTabAt
560	>	(Node<V>[] tab, int i, Node<V> c, Node<V> v) {
561	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
562	>	}
563	>
564	>	private static final <V> void setTabAt
565	>	(Node<V>[] tab, int i, Node<V> v) {
566	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
567	>	}
568	>
569	>	/* ---------------- Nodes -------------- */
570	>
571	>	/**
572	>	* Key-value entry. Note that this is never exported out as a
573	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
574	>	* field of MOVED are special, and do not contain user keys or
575	>	* values.  Otherwise, keys are never null, and null val fields
576	>	* indicate that a node is in the process of being deleted or
577	>	* created. For purposes of read-only access, a key may be read
578	>	* before a val, but can only be used after checking val to be
579	>	* non-null.
580	>	*/
581	>	static class Node<V> {
582		final int hash;
583	<	final K key;
584	<	volatile V value;
585	<	volatile HashEntry<K,V> next;
583	>	final Object key;
584	>	volatile V val;
585	>	volatile Node<V> next;
586
587	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
587	>	Node(int hash, Object key, V val, Node<V> next) {
588		this.hash = hash;
589		this.key = key;
590	<	this.value = value;
590	>	this.val = val;
591		this.next = next;
592		}
593	+	}
594
595	<	/**
189	<	* Sets next field with volatile write semantics.  (See above
190	<	* about use of putOrderedObject.)
191	<	*/
192	<	final void setNext(HashEntry<K,V> n) {
193	<	UNSAFE.putOrderedObject(this, nextOffset, n);
194	<	}
595	>	/* ---------------- TreeBins -------------- */
596
597	<	// Unsafe mechanics
598	<	static final sun.misc.Unsafe UNSAFE;
599	<	static final long nextOffset;
600	<	static {
601	<	try {
602	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
603	<	Class k = HashEntry.class;
604	<	nextOffset = UNSAFE.objectFieldOffset
605	<	(k.getDeclaredField("next"));
606	<	} catch (Exception e) {
607	<	throw new Error(e);
608	<	}
597	>	/**
598	>	* Nodes for use in TreeBins
599	>	*/
600	>	static final class TreeNode<V> extends Node<V> {
601	>	TreeNode<V> parent;  // red-black tree links
602	>	TreeNode<V> left;
603	>	TreeNode<V> right;
604	>	TreeNode<V> prev;    // needed to unlink next upon deletion
605	>	boolean red;
606	>
607	>	TreeNode(int hash, Object key, V val, Node<V> next, TreeNode<V> parent) {
608	>	super(hash, key, val, next);
609	>	this.parent = parent;
610		}
611		}
612
613		/**
614	<	* Gets the ith element of given table (if nonnull) with volatile
615	<	* read semantics. Note: This is manually integrated into a few
616	<	* performance-sensitive methods to reduce call overhead.
617	<	*/
618	<	@SuppressWarnings("unchecked")
619	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
620	<	return (tab == null) ? null :
621	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
622	<	(tab, ((long)i << TSHIFT) + TBASE);
623	<	}
624	<
625	<	/**
626	<	* Sets the ith element of given table, with volatile write
627	<	* semantics. (See above about use of putOrderedObject.)
628	<	*/
629	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
630	<	HashEntry<K,V> e) {
631	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
632	<	}
633	<
634	<	/**
635	<	* Applies a supplemental hash function to a given hashCode, which
636	<	* defends against poor quality hash functions.  This is critical
637	<	* because ConcurrentHashMap uses power-of-two length hash tables,
638	<	* that otherwise encounter collisions for hashCodes that do not
639	<	* differ in lower or upper bits.
640	<	*/
641	<	private static int hash(int h) {
642	<	// Spread bits to regularize both segment and index locations,
643	<	// using variant of single-word Wang/Jenkins hash.
644	<	h += (h <<  15) ^ 0xffffcd7d;
645	<	h ^= (h >>> 10);
646	<	h += (h <<   3);
647	<	h ^= (h >>>  6);
648	<	h += (h <<   2) + (h << 14);
649	<	return h ^ (h >>> 16);
650	<	}
651	<
652	<	/**
653	<	* Segments are specialized versions of hash tables.  This
654	<	* subclasses from ReentrantLock opportunistically, just to
655	<	* simplify some locking and avoid separate construction.
656	<	*/
255	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
256	<	/*
257	<	* Segments maintain a table of entry lists that are always
258	<	* kept in a consistent state, so can be read (via volatile
259	<	* reads of segments and tables) without locking.  This
260	<	* requires replicating nodes when necessary during table
261	<	* resizing, so the old lists can be traversed by readers
262	<	* still using old version of table.
263	<	*
264	<	* This class defines only mutative methods requiring locking.
265	<	* Except as noted, the methods of this class perform the
266	<	* per-segment versions of ConcurrentHashMap methods.  (Other
267	<	* methods are integrated directly into ConcurrentHashMap
268	<	* methods.) These mutative methods use a form of controlled
269	<	* spinning on contention via methods scanAndLock and
270	<	* scanAndLockForPut. These intersperse tryLocks with
271	<	* traversals to locate nodes.  The main benefit is to absorb
272	<	* cache misses (which are very common for hash tables) while
273	<	* obtaining locks so that traversal is faster once
274	<	* acquired. We do not actually use the found nodes since they
275	<	* must be re-acquired under lock anyway to ensure sequential
276	<	* consistency of updates (and in any case may be undetectably
277	<	* stale), but they will normally be much faster to re-locate.
278	<	* Also, scanAndLockForPut speculatively creates a fresh node
279	<	* to use in put if no node is found.
280	<	*/
281	<
614	>	* A specialized form of red-black tree for use in bins
615	>	* whose size exceeds a threshold.
616	>	*
617	>	* TreeBins use a special form of comparison for search and
618	>	* related operations (which is the main reason we cannot use
619	>	* existing collections such as TreeMaps). TreeBins contain
620	>	* Comparable elements, but may contain others, as well as
621	>	* elements that are Comparable but not necessarily Comparable<T>
622	>	* for the same T, so we cannot invoke compareTo among them. To
623	>	* handle this, the tree is ordered primarily by hash value, then
624	>	* by getClass().getName() order, and then by Comparator order
625	>	* among elements of the same class.  On lookup at a node, if
626	>	* elements are not comparable or compare as 0, both left and
627	>	* right children may need to be searched in the case of tied hash
628	>	* values. (This corresponds to the full list search that would be
629	>	* necessary if all elements were non-Comparable and had tied
630	>	* hashes.)  The red-black balancing code is updated from
631	>	* pre-jdk-collections
632	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
633	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
634	>	* Algorithms" (CLR).
635	>	*
636	>	* TreeBins also maintain a separate locking discipline than
637	>	* regular bins. Because they are forwarded via special MOVED
638	>	* nodes at bin heads (which can never change once established),
639	>	* we cannot use those nodes as locks. Instead, TreeBin
640	>	* extends AbstractQueuedSynchronizer to support a simple form of
641	>	* read-write lock. For update operations and table validation,
642	>	* the exclusive form of lock behaves in the same way as bin-head
643	>	* locks. However, lookups use shared read-lock mechanics to allow
644	>	* multiple readers in the absence of writers.  Additionally,
645	>	* these lookups do not ever block: While the lock is not
646	>	* available, they proceed along the slow traversal path (via
647	>	* next-pointers) until the lock becomes available or the list is
648	>	* exhausted, whichever comes first. (These cases are not fast,
649	>	* but maximize aggregate expected throughput.)  The AQS mechanics
650	>	* for doing this are straightforward.  The lock state is held as
651	>	* AQS getState().  Read counts are negative; the write count (1)
652	>	* is positive.  There are no signalling preferences among readers
653	>	* and writers. Since we don't need to export full Lock API, we
654	>	* just override the minimal AQS methods and use them directly.
655	>	*/
656	>	static final class TreeBin<V> extends AbstractQueuedSynchronizer {
657		private static final long serialVersionUID = 2249069246763182397L;
658	+	transient TreeNode<V> root;  // root of tree
659	+	transient TreeNode<V> first; // head of next-pointer list
660
661	<	/**
662	<	* The maximum number of times to tryLock in a prescan before
663	<	* possibly blocking on acquire in preparation for a locked
664	<	* segment operation. On multiprocessors, using a bounded
665	<	* number of retries maintains cache acquired while locating
666	<	* nodes.
667	<	*/
668	<	static final int MAX_SCAN_RETRIES =
669	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
661	>	/* AQS overrides */
662	>	public final boolean isHeldExclusively() { return getState() > 0; }
663	>	public final boolean tryAcquire(int ignore) {
664	>	if (compareAndSetState(0, 1)) {
665	>	setExclusiveOwnerThread(Thread.currentThread());
666	>	return true;
667	>	}
668	>	return false;
669	>	}
670	>	public final boolean tryRelease(int ignore) {
671	>	setExclusiveOwnerThread(null);
672	>	setState(0);
673	>	return true;
674	>	}
675	>	public final int tryAcquireShared(int ignore) {
676	>	for (int c;;) {
677	>	if ((c = getState()) > 0)
678	>	return -1;
679	>	if (compareAndSetState(c, c -1))
680	>	return 1;
681	>	}
682	>	}
683	>	public final boolean tryReleaseShared(int ignore) {
684	>	int c;
685	>	do {} while (!compareAndSetState(c = getState(), c + 1));
686	>	return c == -1;
687	>	}
688	>
689	>	/** From CLR */
690	>	private void rotateLeft(TreeNode<V> p) {
691	>	if (p != null) {
692	>	TreeNode<V> r = p.right, pp, rl;
693	>	if ((rl = p.right = r.left) != null)
694	>	rl.parent = p;
695	>	if ((pp = r.parent = p.parent) == null)
696	>	root = r;
697	>	else if (pp.left == p)
698	>	pp.left = r;
699	>	else
700	>	pp.right = r;
701	>	r.left = p;
702	>	p.parent = r;
703	>	}
704	>	}
705
706	<	/**
707	<	* The per-segment table. Elements are accessed via
708	<	* entryAt/setEntryAt providing volatile semantics.
709	<	*/
710	<	transient volatile HashEntry<K,V>[] table;
706	>	/** From CLR */
707	>	private void rotateRight(TreeNode<V> p) {
708	>	if (p != null) {
709	>	TreeNode<V> l = p.left, pp, lr;
710	>	if ((lr = p.left = l.right) != null)
711	>	lr.parent = p;
712	>	if ((pp = l.parent = p.parent) == null)
713	>	root = l;
714	>	else if (pp.right == p)
715	>	pp.right = l;
716	>	else
717	>	pp.left = l;
718	>	l.right = p;
719	>	p.parent = l;
720	>	}
721	>	}
722
723		/**
724	<	* The number of elements. Accessed only either within locks
725	<	* or among other volatile reads that maintain visibility.
724	>	* Returns the TreeNode (or null if not found) for the given key
725	>	* starting at given root.
726		*/
727	<	transient int count;
727	>	@SuppressWarnings("unchecked") final TreeNode<V> getTreeNode
728	>	(int h, Object k, TreeNode<V> p) {
729	>	Class<?> c = k.getClass();
730	>	while (p != null) {
731	>	int dir, ph;  Object pk; Class<?> pc;
732	>	if ((ph = p.hash) == h) {
733	>	if ((pk = p.key) == k || k.equals(pk))
734	>	return p;
735	>	if (c != (pc = pk.getClass()) ||
736	>	!(k instanceof Comparable) ||
737	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
738	>	if ((dir = (c == pc) ? 0 :
739	>	c.getName().compareTo(pc.getName())) == 0) {
740	>	TreeNode<V> r = null, pl, pr; // check both sides
741	>	if ((pr = p.right) != null && h >= pr.hash &&
742	>	(r = getTreeNode(h, k, pr)) != null)
743	>	return r;
744	>	else if ((pl = p.left) != null && h <= pl.hash)
745	>	dir = -1;
746	>	else // nothing there
747	>	return null;
748	>	}
749	>	}
750	>	}
751	>	else
752	>	dir = (h < ph) ? -1 : 1;
753	>	p = (dir > 0) ? p.right : p.left;
754	>	}
755	>	return null;
756	>	}
757
758		/**
759	<	* The total number of mutative operations in this segment.
760	<	* Even though this may overflows 32 bits, it provides
761	<	* sufficient accuracy for stability checks in CHM isEmpty()
310	<	* and size() methods.  Accessed only either within locks or
311	<	* among other volatile reads that maintain visibility.
759	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
760	>	* read-lock to call getTreeNode, but during failure to get
761	>	* lock, searches along next links.
762		*/
763	<	transient int modCount;
763	>	final V getValue(int h, Object k) {
764	>	Node<V> r = null;
765	>	int c = getState(); // Must read lock state first
766	>	for (Node<V> e = first; e != null; e = e.next) {
767	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
768	>	try {
769	>	r = getTreeNode(h, k, root);
770	>	} finally {
771	>	releaseShared(0);
772	>	}
773	>	break;
774	>	}
775	>	else if (e.hash == h && k.equals(e.key)) {
776	>	r = e;
777	>	break;
778	>	}
779	>	else
780	>	c = getState();
781	>	}
782	>	return r == null ? null : r.val;
783	>	}
784
785		/**
786	<	* The table is rehashed when its size exceeds this threshold.
787	<	* (The value of this field is always <tt>(int)(capacity *
318	<	* loadFactor)</tt>.)
786	>	* Finds or adds a node.
787	>	* @return null if added
788		*/
789	<	transient int threshold;
789	>	@SuppressWarnings("unchecked") final TreeNode<V> putTreeNode
790	>	(int h, Object k, V v) {
791	>	Class<?> c = k.getClass();
792	>	TreeNode<V> pp = root, p = null;
793	>	int dir = 0;
794	>	while (pp != null) { // find existing node or leaf to insert at
795	>	int ph;  Object pk; Class<?> pc;
796	>	p = pp;
797	>	if ((ph = p.hash) == h) {
798	>	if ((pk = p.key) == k || k.equals(pk))
799	>	return p;
800	>	if (c != (pc = pk.getClass()) ||
801	>	!(k instanceof Comparable) ||
802	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
803	>	TreeNode<V> s = null, r = null, pr;
804	>	if ((dir = (c == pc) ? 0 :
805	>	c.getName().compareTo(pc.getName())) == 0) {
806	>	if ((pr = p.right) != null && h >= pr.hash &&
807	>	(r = getTreeNode(h, k, pr)) != null)
808	>	return r;
809	>	else // continue left
810	>	dir = -1;
811	>	}
812	>	else if ((pr = p.right) != null && h >= pr.hash)
813	>	s = pr;
814	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
815	>	return r;
816	>	}
817	>	}
818	>	else
819	>	dir = (h < ph) ? -1 : 1;
820	>	pp = (dir > 0) ? p.right : p.left;
821	>	}
822	>
823	>	TreeNode<V> f = first;
824	>	TreeNode<V> x = first = new TreeNode<V>(h, k, v, f, p);
825	>	if (p == null)
826	>	root = x;
827	>	else { // attach and rebalance; adapted from CLR
828	>	TreeNode<V> xp, xpp;
829	>	if (f != null)
830	>	f.prev = x;
831	>	if (dir <= 0)
832	>	p.left = x;
833	>	else
834	>	p.right = x;
835	>	x.red = true;
836	>	while (x != null && (xp = x.parent) != null && xp.red &&
837	>	(xpp = xp.parent) != null) {
838	>	TreeNode<V> xppl = xpp.left;
839	>	if (xp == xppl) {
840	>	TreeNode<V> y = xpp.right;
841	>	if (y != null && y.red) {
842	>	y.red = false;
843	>	xp.red = false;
844	>	xpp.red = true;
845	>	x = xpp;
846	>	}
847	>	else {
848	>	if (x == xp.right) {
849	>	rotateLeft(x = xp);
850	>	xpp = (xp = x.parent) == null ? null : xp.parent;
851	>	}
852	>	if (xp != null) {
853	>	xp.red = false;
854	>	if (xpp != null) {
855	>	xpp.red = true;
856	>	rotateRight(xpp);
857	>	}
858	>	}
859	>	}
860	>	}
861	>	else {
862	>	TreeNode<V> y = xppl;
863	>	if (y != null && y.red) {
864	>	y.red = false;
865	>	xp.red = false;
866	>	xpp.red = true;
867	>	x = xpp;
868	>	}
869	>	else {
870	>	if (x == xp.left) {
871	>	rotateRight(x = xp);
872	>	xpp = (xp = x.parent) == null ? null : xp.parent;
873	>	}
874	>	if (xp != null) {
875	>	xp.red = false;
876	>	if (xpp != null) {
877	>	xpp.red = true;
878	>	rotateLeft(xpp);
879	>	}
880	>	}
881	>	}
882	>	}
883	>	}
884	>	TreeNode<V> r = root;
885	>	if (r != null && r.red)
886	>	r.red = false;
887	>	}
888	>	return null;
889	>	}
890
891		/**
892	<	* The load factor for the hash table.  Even though this value
893	<	* is same for all segments, it is replicated to avoid needing
894	<	* links to outer object.
895	<	* @serial
892	>	* Removes the given node, that must be present before this
893	>	* call.  This is messier than typical red-black deletion code
894	>	* because we cannot swap the contents of an interior node
895	>	* with a leaf successor that is pinned by "next" pointers
896	>	* that are accessible independently of lock. So instead we
897	>	* swap the tree linkages.
898		*/
899	<	final float loadFactor;
899	>	final void deleteTreeNode(TreeNode<V> p) {
900	>	TreeNode<V> next = (TreeNode<V>)p.next; // unlink traversal pointers
901	>	TreeNode<V> pred = p.prev;
902	>	if (pred == null)
903	>	first = next;
904	>	else
905	>	pred.next = next;
906	>	if (next != null)
907	>	next.prev = pred;
908	>	TreeNode<V> replacement;
909	>	TreeNode<V> pl = p.left;
910	>	TreeNode<V> pr = p.right;
911	>	if (pl != null && pr != null) {
912	>	TreeNode<V> s = pr, sl;
913	>	while ((sl = s.left) != null) // find successor
914	>	s = sl;
915	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
916	>	TreeNode<V> sr = s.right;
917	>	TreeNode<V> pp = p.parent;
918	>	if (s == pr) { // p was s's direct parent
919	>	p.parent = s;
920	>	s.right = p;
921	>	}
922	>	else {
923	>	TreeNode<V> sp = s.parent;
924	>	if ((p.parent = sp) != null) {
925	>	if (s == sp.left)
926	>	sp.left = p;
927	>	else
928	>	sp.right = p;
929	>	}
930	>	if ((s.right = pr) != null)
931	>	pr.parent = s;
932	>	}
933	>	p.left = null;
934	>	if ((p.right = sr) != null)
935	>	sr.parent = p;
936	>	if ((s.left = pl) != null)
937	>	pl.parent = s;
938	>	if ((s.parent = pp) == null)
939	>	root = s;
940	>	else if (p == pp.left)
941	>	pp.left = s;
942	>	else
943	>	pp.right = s;
944	>	replacement = sr;
945	>	}
946	>	else
947	>	replacement = (pl != null) ? pl : pr;
948	>	TreeNode<V> pp = p.parent;
949	>	if (replacement == null) {
950	>	if (pp == null) {
951	>	root = null;
952	>	return;
953	>	}
954	>	replacement = p;
955	>	}
956	>	else {
957	>	replacement.parent = pp;
958	>	if (pp == null)
959	>	root = replacement;
960	>	else if (p == pp.left)
961	>	pp.left = replacement;
962	>	else
963	>	pp.right = replacement;
964	>	p.left = p.right = p.parent = null;
965	>	}
966	>	if (!p.red) { // rebalance, from CLR
967	>	TreeNode<V> x = replacement;
968	>	while (x != null) {
969	>	TreeNode<V> xp, xpl;
970	>	if (x.red || (xp = x.parent) == null) {
971	>	x.red = false;
972	>	break;
973	>	}
974	>	if (x == (xpl = xp.left)) {
975	>	TreeNode<V> sib = xp.right;
976	>	if (sib != null && sib.red) {
977	>	sib.red = false;
978	>	xp.red = true;
979	>	rotateLeft(xp);
980	>	sib = (xp = x.parent) == null ? null : xp.right;
981	>	}
982	>	if (sib == null)
983	>	x = xp;
984	>	else {
985	>	TreeNode<V> sl = sib.left, sr = sib.right;
986	>	if ((sr == null || !sr.red) &&
987	>	(sl == null || !sl.red)) {
988	>	sib.red = true;
989	>	x = xp;
990	>	}
991	>	else {
992	>	if (sr == null || !sr.red) {
993	>	if (sl != null)
994	>	sl.red = false;
995	>	sib.red = true;
996	>	rotateRight(sib);
997	>	sib = (xp = x.parent) == null ?
998	>	null : xp.right;
999	>	}
1000	>	if (sib != null) {
1001	>	sib.red = (xp == null) ? false : xp.red;
1002	>	if ((sr = sib.right) != null)
1003	>	sr.red = false;
1004	>	}
1005	>	if (xp != null) {
1006	>	xp.red = false;
1007	>	rotateLeft(xp);
1008	>	}
1009	>	x = root;
1010	>	}
1011	>	}
1012	>	}
1013	>	else { // symmetric
1014	>	TreeNode<V> sib = xpl;
1015	>	if (sib != null && sib.red) {
1016	>	sib.red = false;
1017	>	xp.red = true;
1018	>	rotateRight(xp);
1019	>	sib = (xp = x.parent) == null ? null : xp.left;
1020	>	}
1021	>	if (sib == null)
1022	>	x = xp;
1023	>	else {
1024	>	TreeNode<V> sl = sib.left, sr = sib.right;
1025	>	if ((sl == null || !sl.red) &&
1026	>	(sr == null || !sr.red)) {
1027	>	sib.red = true;
1028	>	x = xp;
1029	>	}
1030	>	else {
1031	>	if (sl == null || !sl.red) {
1032	>	if (sr != null)
1033	>	sr.red = false;
1034	>	sib.red = true;
1035	>	rotateLeft(sib);
1036	>	sib = (xp = x.parent) == null ?
1037	>	null : xp.left;
1038	>	}
1039	>	if (sib != null) {
1040	>	sib.red = (xp == null) ? false : xp.red;
1041	>	if ((sl = sib.left) != null)
1042	>	sl.red = false;
1043	>	}
1044	>	if (xp != null) {
1045	>	xp.red = false;
1046	>	rotateRight(xp);
1047	>	}
1048	>	x = root;
1049	>	}
1050	>	}
1051	>	}
1052	>	}
1053	>	}
1054	>	if (p == replacement && (pp = p.parent) != null) {
1055	>	if (p == pp.left) // detach pointers
1056	>	pp.left = null;
1057	>	else if (p == pp.right)
1058	>	pp.right = null;
1059	>	p.parent = null;
1060	>	}
1061	>	}
1062	>	}
1063	>
1064	>	/* ---------------- Collision reduction methods -------------- */
1065	>
1066	>	/**
1067	>	* Spreads higher bits to lower, and also forces top bit to 0.
1068	>	* Because the table uses power-of-two masking, sets of hashes
1069	>	* that vary only in bits above the current mask will always
1070	>	* collide. (Among known examples are sets of Float keys holding
1071	>	* consecutive whole numbers in small tables.)  To counter this,
1072	>	* we apply a transform that spreads the impact of higher bits
1073	>	* downward. There is a tradeoff between speed, utility, and
1074	>	* quality of bit-spreading. Because many common sets of hashes
1075	>	* are already reasonably distributed across bits (so don't benefit
1076	>	* from spreading), and because we use trees to handle large sets
1077	>	* of collisions in bins, we don't need excessively high quality.
1078	>	*/
1079	>	private static final int spread(int h) {
1080	>	h ^= (h >>> 18) ^ (h >>> 12);
1081	>	return (h ^ (h >>> 10)) & HASH_BITS;
1082	>	}
1083
1084	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
1085	<	this.loadFactor = lf;
1086	<	this.threshold = threshold;
1087	<	this.table = tab;
1084	>	/**
1085	>	* Replaces a list bin with a tree bin if key is comparable.  Call
1086	>	* only when locked.
1087	>	*/
1088	>	private final void replaceWithTreeBin(Node<V>[] tab, int index, Object key) {
1089	>	if (key instanceof Comparable) {
1090	>	TreeBin<V> t = new TreeBin<V>();
1091	>	for (Node<V> e = tabAt(tab, index); e != null; e = e.next)
1092	>	t.putTreeNode(e.hash, e.key, e.val);
1093	>	setTabAt(tab, index, new Node<V>(MOVED, t, null, null));
1094		}
1095	+	}
1096
1097	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
1098	<	HashEntry<K,V> node = tryLock() ? null :
1099	<	scanAndLockForPut(key, hash, value);
1100	<	V oldValue;
1101	<	try {
1102	<	HashEntry<K,V>[] tab = table;
1103	<	int index = (tab.length - 1) & hash;
1104	<	HashEntry<K,V> first = entryAt(tab, index);
1105	<	for (HashEntry<K,V> e = first;;) {
1106	<	if (e != null) {
1107	<	K k;
1108	<	if ((k = e.key) == key ||
1109	<	(e.hash == hash && key.equals(k))) {
1110	<	oldValue = e.value;
1111	<	if (!onlyIfAbsent) {
1112	<	e.value = value;
1113	<	++modCount;
1097	>	/* ---------------- Internal access and update methods -------------- */
1098	>
1099	>	/** Implementation for get and containsKey */
1100	>	@SuppressWarnings("unchecked") private final V internalGet(Object k) {
1101	>	int h = spread(k.hashCode());
1102	>	retry: for (Node<V>[] tab = table; tab != null;) {
1103	>	Node<V> e; Object ek; V ev; int eh; // locals to read fields once
1104	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1105	>	if ((eh = e.hash) < 0) {
1106	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1107	>	return ((TreeBin<V>)ek).getValue(h, k);
1108	>	else {                      // restart with new table
1109	>	tab = (Node<V>[])ek;
1110	>	continue retry;
1111	>	}
1112	>	}
1113	>	else if (eh == h && (ev = e.val) != null &&
1114	>	((ek = e.key) == k || k.equals(ek)))
1115	>	return ev;
1116	>	}
1117	>	break;
1118	>	}
1119	>	return null;
1120	>	}
1121	>
1122	>	/**
1123	>	* Implementation for the four public remove/replace methods:
1124	>	* Replaces node value with v, conditional upon match of cv if
1125	>	* non-null.  If resulting value is null, delete.
1126	>	*/
1127	>	@SuppressWarnings("unchecked") private final V internalReplace
1128	>	(Object k, V v, Object cv) {
1129	>	int h = spread(k.hashCode());
1130	>	V oldVal = null;
1131	>	for (Node<V>[] tab = table;;) {
1132	>	Node<V> f; int i, fh; Object fk;
1133	>	if (tab == null ||
1134	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1135	>	break;
1136	>	else if ((fh = f.hash) < 0) {
1137	>	if ((fk = f.key) instanceof TreeBin) {
1138	>	TreeBin<V> t = (TreeBin<V>)fk;
1139	>	boolean validated = false;
1140	>	boolean deleted = false;
1141	>	t.acquire(0);
1142	>	try {
1143	>	if (tabAt(tab, i) == f) {
1144	>	validated = true;
1145	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1146	>	if (p != null) {
1147	>	V pv = p.val;
1148	>	if (cv == null || cv == pv || cv.equals(pv)) {
1149	>	oldVal = pv;
1150	>	if ((p.val = v) == null) {
1151	>	deleted = true;
1152	>	t.deleteTreeNode(p);
1153	>	}
1154	>	}
1155		}
354	–	break;
1156		}
1157	<	e = e.next;
1157	>	} finally {
1158	>	t.release(0);
1159		}
1160	<	else {
1161	<	if (node != null)
1162	<	node.setNext(first);
361	<	else
362	<	node = new HashEntry<K,V>(hash, key, value, first);
363	<	int c = count + 1;
364	<	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
365	<	rehash(node);
366	<	else
367	<	setEntryAt(tab, index, node);
368	<	++modCount;
369	<	count = c;
370	<	oldValue = null;
1160	>	if (validated) {
1161	>	if (deleted)
1162	>	addCount(-1L, -1);
1163		break;
1164		}
1165		}
1166	<	} finally {
1167	<	unlock();
1166	>	else
1167	>	tab = (Node<V>[])fk;
1168	>	}
1169	>	else if (fh != h && f.next == null) // precheck
1170	>	break;                          // rules out possible existence
1171	>	else {
1172	>	boolean validated = false;
1173	>	boolean deleted = false;
1174	>	synchronized (f) {
1175	>	if (tabAt(tab, i) == f) {
1176	>	validated = true;
1177	>	for (Node<V> e = f, pred = null;;) {
1178	>	Object ek; V ev;
1179	>	if (e.hash == h &&
1180	>	((ev = e.val) != null) &&
1181	>	((ek = e.key) == k || k.equals(ek))) {
1182	>	if (cv == null || cv == ev || cv.equals(ev)) {
1183	>	oldVal = ev;
1184	>	if ((e.val = v) == null) {
1185	>	deleted = true;
1186	>	Node<V> en = e.next;
1187	>	if (pred != null)
1188	>	pred.next = en;
1189	>	else
1190	>	setTabAt(tab, i, en);
1191	>	}
1192	>	}
1193	>	break;
1194	>	}
1195	>	pred = e;
1196	>	if ((e = e.next) == null)
1197	>	break;
1198	>	}
1199	>	}
1200	>	}
1201	>	if (validated) {
1202	>	if (deleted)
1203	>	addCount(-1L, -1);
1204	>	break;
1205	>	}
1206		}
377	–	return oldValue;
1207		}
1208	+	return oldVal;
1209	+	}
1210
1211	<	/**
1212	<	* Doubles size of table and repacks entries, also adding the
1213	<	* given node to new table
1214	<	*/
1215	<	@SuppressWarnings("unchecked")
1216	<	private void rehash(HashEntry<K,V> node) {
1217	<	/*
1218	<	* Reclassify nodes in each list to new table.  Because we
1219	<	* are using power-of-two expansion, the elements from
1220	<	* each bin must either stay at same index, or move with a
1221	<	* power of two offset. We eliminate unnecessary node
1222	<	* creation by catching cases where old nodes can be
1223	<	* reused because their next fields won't change.
1224	<	* Statistically, at the default threshold, only about
1225	<	* one-sixth of them need cloning when a table
1226	<	* doubles. The nodes they replace will be garbage
1227	<	* collectable as soon as they are no longer referenced by
1228	<	* any reader thread that may be in the midst of
1229	<	* concurrently traversing table. Entry accesses use plain
1230	<	* array indexing because they are followed by volatile
1231	<	* table write.
1232	<	*/
1233	<	HashEntry<K,V>[] oldTable = table;
1234	<	int oldCapacity = oldTable.length;
1235	<	int newCapacity = oldCapacity << 1;
1236	<	threshold = (int)(newCapacity * loadFactor);
1237	<	HashEntry<K,V>[] newTable =
1238	<	(HashEntry<K,V>[]) new HashEntry[newCapacity];
1239	<	int sizeMask = newCapacity - 1;
1240	<	for (int i = 0; i < oldCapacity ; i++) {
1241	<	HashEntry<K,V> e = oldTable[i];
1242	<	if (e != null) {
1243	<	HashEntry<K,V> next = e.next;
1244	<	int idx = e.hash & sizeMask;
1245	<	if (next == null)   //  Single node on list
1246	<	newTable[idx] = e;
1247	<	else { // Reuse consecutive sequence at same slot
1248	<	HashEntry<K,V> lastRun = e;
1249	<	int lastIdx = idx;
1250	<	for (HashEntry<K,V> last = next;
1251	<	last != null;
1252	<	last = last.next) {
1253	<	int k = last.hash & sizeMask;
1254	<	if (k != lastIdx) {
1255	<	lastIdx = k;
1256	<	lastRun = last;
1257	<	}
1258	<	}
1259	<	newTable[lastIdx] = lastRun;
1260	<	// Clone remaining nodes
1261	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1262	<	V v = p.value;
1263	<	int h = p.hash;
1264	<	int k = h & sizeMask;
1265	<	HashEntry<K,V> n = newTable[k];
1266	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
1267	<	}
1268	<	}
1269	<	}
1270	<	}
1271	<	int nodeIndex = node.hash & sizeMask; // add the new node
1272	<	node.setNext(newTable[nodeIndex]);
1273	<	newTable[nodeIndex] = node;
1274	<	table = newTable;
1275	<	}
1276	<
1277	<	/**
1278	<	* Scans for a node containing given key while trying to
1279	<	* acquire lock, creating and returning one if not found. Upon
1280	<	* return, guarantees that lock is held. Unlike in most
1281	<	* methods, calls to method equals are not screened: Since
1282	<	* traversal speed doesn't matter, we might as well help warm
1283	<	* up the associated code and accesses as well.
1284	<	*
1285	<	* @return a new node if key not found, else null
1286	<	*/
1287	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
1288	<	HashEntry<K,V> first = entryForHash(this, hash);
1289	<	HashEntry<K,V> e = first;
1290	<	HashEntry<K,V> node = null;
1291	<	int retries = -1; // negative while locating node
1292	<	while (!tryLock()) {
1293	<	HashEntry<K,V> f; // to recheck first below
1294	<	if (retries < 0) {
1295	<	if (e == null) {
465	<	if (node == null) // speculatively create node
466	<	node = new HashEntry<K,V>(hash, key, value, null);
467	<	retries = 0;
1211	>	/*
1212	>	* Internal versions of insertion methods
1213	>	* All have the same basic structure as the first (internalPut):
1214	>	*  1. If table uninitialized, create
1215	>	*  2. If bin empty, try to CAS new node
1216	>	*  3. If bin stale, use new table
1217	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1218	>	*  5. Lock and validate; if valid, scan and add or update
1219	>	*
1220	>	* The putAll method differs mainly in attempting to pre-allocate
1221	>	* enough table space, and also more lazily performs count updates
1222	>	* and checks.
1223	>	*
1224	>	* Most of the function-accepting methods can't be factored nicely
1225	>	* because they require different functional forms, so instead
1226	>	* sprawl out similar mechanics.
1227	>	*/
1228	>
1229	>	/** Implementation for put and putIfAbsent */
1230	>	@SuppressWarnings("unchecked") private final V internalPut
1231	>	(K k, V v, boolean onlyIfAbsent) {
1232	>	if (k == null || v == null) throw new NullPointerException();
1233	>	int h = spread(k.hashCode());
1234	>	int len = 0;
1235	>	for (Node<V>[] tab = table;;) {
1236	>	int i, fh; Node<V> f; Object fk; V fv;
1237	>	if (tab == null)
1238	>	tab = initTable();
1239	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1240	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null)))
1241	>	break;                   // no lock when adding to empty bin
1242	>	}
1243	>	else if ((fh = f.hash) < 0) {
1244	>	if ((fk = f.key) instanceof TreeBin) {
1245	>	TreeBin<V> t = (TreeBin<V>)fk;
1246	>	V oldVal = null;
1247	>	t.acquire(0);
1248	>	try {
1249	>	if (tabAt(tab, i) == f) {
1250	>	len = 2;
1251	>	TreeNode<V> p = t.putTreeNode(h, k, v);
1252	>	if (p != null) {
1253	>	oldVal = p.val;
1254	>	if (!onlyIfAbsent)
1255	>	p.val = v;
1256	>	}
1257	>	}
1258	>	} finally {
1259	>	t.release(0);
1260	>	}
1261	>	if (len != 0) {
1262	>	if (oldVal != null)
1263	>	return oldVal;
1264	>	break;
1265	>	}
1266	>	}
1267	>	else
1268	>	tab = (Node<V>[])fk;
1269	>	}
1270	>	else if (onlyIfAbsent && fh == h && (fv = f.val) != null &&
1271	>	((fk = f.key) == k || k.equals(fk))) // peek while nearby
1272	>	return fv;
1273	>	else {
1274	>	V oldVal = null;
1275	>	synchronized (f) {
1276	>	if (tabAt(tab, i) == f) {
1277	>	len = 1;
1278	>	for (Node<V> e = f;; ++len) {
1279	>	Object ek; V ev;
1280	>	if (e.hash == h &&
1281	>	(ev = e.val) != null &&
1282	>	((ek = e.key) == k || k.equals(ek))) {
1283	>	oldVal = ev;
1284	>	if (!onlyIfAbsent)
1285	>	e.val = v;
1286	>	break;
1287	>	}
1288	>	Node<V> last = e;
1289	>	if ((e = e.next) == null) {
1290	>	last.next = new Node<V>(h, k, v, null);
1291	>	if (len >= TREE_THRESHOLD)
1292	>	replaceWithTreeBin(tab, i, k);
1293	>	break;
1294	>	}
1295	>	}
1296		}
469	–	else if (key.equals(e.key))
470	–	retries = 0;
471	–	else
472	–	e = e.next;
1297		}
1298	<	else if (++retries > MAX_SCAN_RETRIES) {
1299	<	lock();
1298	>	if (len != 0) {
1299	>	if (oldVal != null)
1300	>	return oldVal;
1301		break;
1302		}
1303	<	else if ((retries & 1) == 0 &&
479	<	(f = entryForHash(this, hash)) != first) {
480	<	e = first = f; // re-traverse if entry changed
481	<	retries = -1;
482	<	}
483	<	}
484	<	return node;
1303	>	}
1304		}
1305	+	addCount(1L, len);
1306	+	return null;
1307	+	}
1308
1309	<	/**
1310	<	* Scans for a node containing the given key while trying to
1311	<	* acquire lock for a remove or replace operation. Upon
1312	<	* return, guarantees that lock is held.  Note that we must
1313	<	* lock even if the key is not found, to ensure sequential
1314	<	* consistency of updates.
1315	<	*/
1316	<	private void scanAndLock(Object key, int hash) {
1317	<	// similar to but simpler than scanAndLockForPut
1318	<	HashEntry<K,V> first = entryForHash(this, hash);
1319	<	HashEntry<K,V> e = first;
1320	<	int retries = -1;
1321	<	while (!tryLock()) {
1322	<	HashEntry<K,V> f;
1323	<	if (retries < 0) {
1324	<	if (e == null || key.equals(e.key))
1325	<	retries = 0;
1326	<	else
1327	<	e = e.next;
1309	>	/** Implementation for computeIfAbsent */
1310	>	@SuppressWarnings("unchecked") private final V internalComputeIfAbsent
1311	>	(K k, Function<? super K, ? extends V> mf) {
1312	>	if (k == null || mf == null)
1313	>	throw new NullPointerException();
1314	>	int h = spread(k.hashCode());
1315	>	V val = null;
1316	>	int len = 0;
1317	>	for (Node<V>[] tab = table;;) {
1318	>	Node<V> f; int i; Object fk;
1319	>	if (tab == null)
1320	>	tab = initTable();
1321	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1322	>	Node<V> node = new Node<V>(h, k, null, null);
1323	>	synchronized (node) {
1324	>	if (casTabAt(tab, i, null, node)) {
1325	>	len = 1;
1326	>	try {
1327	>	if ((val = mf.apply(k)) != null)
1328	>	node.val = val;
1329	>	} finally {
1330	>	if (val == null)
1331	>	setTabAt(tab, i, null);
1332	>	}
1333	>	}
1334		}
1335	<	else if (++retries > MAX_SCAN_RETRIES) {
508	<	lock();
1335	>	if (len != 0)
1336		break;
1337	+	}
1338	+	else if (f.hash < 0) {
1339	+	if ((fk = f.key) instanceof TreeBin) {
1340	+	TreeBin<V> t = (TreeBin<V>)fk;
1341	+	boolean added = false;
1342	+	t.acquire(0);
1343	+	try {
1344	+	if (tabAt(tab, i) == f) {
1345	+	len = 1;
1346	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1347	+	if (p != null)
1348	+	val = p.val;
1349	+	else if ((val = mf.apply(k)) != null) {
1350	+	added = true;
1351	+	len = 2;
1352	+	t.putTreeNode(h, k, val);
1353	+	}
1354	+	}
1355	+	} finally {
1356	+	t.release(0);
1357	+	}
1358	+	if (len != 0) {
1359	+	if (!added)
1360	+	return val;
1361	+	break;
1362	+	}
1363	+	}
1364	+	else
1365	+	tab = (Node<V>[])fk;
1366	+	}
1367	+	else {
1368	+	for (Node<V> e = f; e != null; e = e.next) { // prescan
1369	+	Object ek; V ev;
1370	+	if (e.hash == h && (ev = e.val) != null &&
1371	+	((ek = e.key) == k || k.equals(ek)))
1372	+	return ev;
1373	+	}
1374	+	boolean added = false;
1375	+	synchronized (f) {
1376	+	if (tabAt(tab, i) == f) {
1377	+	len = 1;
1378	+	for (Node<V> e = f;; ++len) {
1379	+	Object ek; V ev;
1380	+	if (e.hash == h &&
1381	+	(ev = e.val) != null &&
1382	+	((ek = e.key) == k || k.equals(ek))) {
1383	+	val = ev;
1384	+	break;
1385	+	}
1386	+	Node<V> last = e;
1387	+	if ((e = e.next) == null) {
1388	+	if ((val = mf.apply(k)) != null) {
1389	+	added = true;
1390	+	last.next = new Node<V>(h, k, val, null);
1391	+	if (len >= TREE_THRESHOLD)
1392	+	replaceWithTreeBin(tab, i, k);
1393	+	}
1394	+	break;
1395	+	}
1396	+	}
1397	+	}
1398		}
1399	<	else if ((retries & 1) == 0 &&
1400	<	(f = entryForHash(this, hash)) != first) {
1401	<	e = first = f;
1402	<	retries = -1;
1399	>	if (len != 0) {
1400	>	if (!added)
1401	>	return val;
1402	>	break;
1403		}
1404		}
1405		}
1406	+	if (val != null)
1407	+	addCount(1L, len);
1408	+	return val;
1409	+	}
1410
1411	<	/**
1412	<	* Remove; match on key only if value null, else match both.
1413	<	*/
1414	<	final V remove(Object key, int hash, Object value) {
1415	<	if (!tryLock())
1416	<	scanAndLock(key, hash);
1417	<	V oldValue = null;
1418	<	try {
1419	<	HashEntry<K,V>[] tab = table;
1420	<	int index = (tab.length - 1) & hash;
1421	<	HashEntry<K,V> e = entryAt(tab, index);
1422	<	HashEntry<K,V> pred = null;
1423	<	while (e != null) {
1424	<	K k;
1425	<	HashEntry<K,V> next = e.next;
1426	<	if ((k = e.key) == key ||
1427	<	(e.hash == hash && key.equals(k))) {
1428	<	V v = e.value;
1429	<	if (value == null || value == v || value.equals(v)) {
1430	<	if (pred == null)
1431	<	setEntryAt(tab, index, next);
1432	<	else
1433	<	pred.setNext(next);
1434	<	++modCount;
1435	<	--count;
1436	<	oldValue = v;
1411	>	/** Implementation for compute */
1412	>	@SuppressWarnings("unchecked") private final V internalCompute
1413	>	(K k, boolean onlyIfPresent,
1414	>	BiFunction<? super K, ? super V, ? extends V> mf) {
1415	>	if (k == null || mf == null)
1416	>	throw new NullPointerException();
1417	>	int h = spread(k.hashCode());
1418	>	V val = null;
1419	>	int delta = 0;
1420	>	int len = 0;
1421	>	for (Node<V>[] tab = table;;) {
1422	>	Node<V> f; int i, fh; Object fk;
1423	>	if (tab == null)
1424	>	tab = initTable();
1425	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1426	>	if (onlyIfPresent)
1427	>	break;
1428	>	Node<V> node = new Node<V>(h, k, null, null);
1429	>	synchronized (node) {
1430	>	if (casTabAt(tab, i, null, node)) {
1431	>	try {
1432	>	len = 1;
1433	>	if ((val = mf.apply(k, null)) != null) {
1434	>	node.val = val;
1435	>	delta = 1;
1436	>	}
1437	>	} finally {
1438	>	if (delta == 0)
1439	>	setTabAt(tab, i, null);
1440	>	}
1441	>	}
1442	>	}
1443	>	if (len != 0)
1444	>	break;
1445	>	}
1446	>	else if ((fh = f.hash) < 0) {
1447	>	if ((fk = f.key) instanceof TreeBin) {
1448	>	TreeBin<V> t = (TreeBin<V>)fk;
1449	>	t.acquire(0);
1450	>	try {
1451	>	if (tabAt(tab, i) == f) {
1452	>	len = 1;
1453	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1454	>	if (p == null && onlyIfPresent)
1455	>	break;
1456	>	V pv = (p == null) ? null : p.val;
1457	>	if ((val = mf.apply(k, pv)) != null) {
1458	>	if (p != null)
1459	>	p.val = val;
1460	>	else {
1461	>	len = 2;
1462	>	delta = 1;
1463	>	t.putTreeNode(h, k, val);
1464	>	}
1465	>	}
1466	>	else if (p != null) {
1467	>	delta = -1;
1468	>	t.deleteTreeNode(p);
1469	>	}
1470		}
1471	+	} finally {
1472	+	t.release(0);
1473	+	}
1474	+	if (len != 0)
1475		break;
1476	+	}
1477	+	else
1478	+	tab = (Node<V>[])fk;
1479	+	}
1480	+	else {
1481	+	synchronized (f) {
1482	+	if (tabAt(tab, i) == f) {
1483	+	len = 1;
1484	+	for (Node<V> e = f, pred = null;; ++len) {
1485	+	Object ek; V ev;
1486	+	if (e.hash == h &&
1487	+	(ev = e.val) != null &&
1488	+	((ek = e.key) == k || k.equals(ek))) {
1489	+	val = mf.apply(k, ev);
1490	+	if (val != null)
1491	+	e.val = val;
1492	+	else {
1493	+	delta = -1;
1494	+	Node<V> en = e.next;
1495	+	if (pred != null)
1496	+	pred.next = en;
1497	+	else
1498	+	setTabAt(tab, i, en);
1499	+	}
1500	+	break;
1501	+	}
1502	+	pred = e;
1503	+	if ((e = e.next) == null) {
1504	+	if (!onlyIfPresent &&
1505	+	(val = mf.apply(k, null)) != null) {
1506	+	pred.next = new Node<V>(h, k, val, null);
1507	+	delta = 1;
1508	+	if (len >= TREE_THRESHOLD)
1509	+	replaceWithTreeBin(tab, i, k);
1510	+	}
1511	+	break;
1512	+	}
1513	+	}
1514		}
548	–	pred = e;
549	–	e = next;
1515		}
1516	<	} finally {
1517	<	unlock();
1516	>	if (len != 0)
1517	>	break;
1518		}
554	–	return oldValue;
1519		}
1520	+	if (delta != 0)
1521	+	addCount((long)delta, len);
1522	+	return val;
1523	+	}
1524
1525	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
1526	<	if (!tryLock())
1527	<	scanAndLock(key, hash);
1528	<	boolean replaced = false;
1529	<	try {
1530	<	HashEntry<K,V> e;
1531	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1532	<	K k;
1533	<	if ((k = e.key) == key ||
1534	<	(e.hash == hash && key.equals(k))) {
1535	<	if (oldValue.equals(e.value)) {
1536	<	e.value = newValue;
1537	<	++modCount;
1538	<	replaced = true;
1525	>	/** Implementation for merge */
1526	>	@SuppressWarnings("unchecked") private final V internalMerge
1527	>	(K k, V v, BiFunction<? super V, ? super V, ? extends V> mf) {
1528	>	if (k == null || v == null || mf == null)
1529	>	throw new NullPointerException();
1530	>	int h = spread(k.hashCode());
1531	>	V val = null;
1532	>	int delta = 0;
1533	>	int len = 0;
1534	>	for (Node<V>[] tab = table;;) {
1535	>	int i; Node<V> f; Object fk; V fv;
1536	>	if (tab == null)
1537	>	tab = initTable();
1538	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1539	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1540	>	delta = 1;
1541	>	val = v;
1542	>	break;
1543	>	}
1544	>	}
1545	>	else if (f.hash < 0) {
1546	>	if ((fk = f.key) instanceof TreeBin) {
1547	>	TreeBin<V> t = (TreeBin<V>)fk;
1548	>	t.acquire(0);
1549	>	try {
1550	>	if (tabAt(tab, i) == f) {
1551	>	len = 1;
1552	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1553	>	val = (p == null) ? v : mf.apply(p.val, v);
1554	>	if (val != null) {
1555	>	if (p != null)
1556	>	p.val = val;
1557	>	else {
1558	>	len = 2;
1559	>	delta = 1;
1560	>	t.putTreeNode(h, k, val);
1561	>	}
1562	>	}
1563	>	else if (p != null) {
1564	>	delta = -1;
1565	>	t.deleteTreeNode(p);
1566	>	}
1567		}
1568	+	} finally {
1569	+	t.release(0);
1570	+	}
1571	+	if (len != 0)
1572		break;
1573	+	}
1574	+	else
1575	+	tab = (Node<V>[])fk;
1576	+	}
1577	+	else {
1578	+	synchronized (f) {
1579	+	if (tabAt(tab, i) == f) {
1580	+	len = 1;
1581	+	for (Node<V> e = f, pred = null;; ++len) {
1582	+	Object ek; V ev;
1583	+	if (e.hash == h &&
1584	+	(ev = e.val) != null &&
1585	+	((ek = e.key) == k || k.equals(ek))) {
1586	+	val = mf.apply(ev, v);
1587	+	if (val != null)
1588	+	e.val = val;
1589	+	else {
1590	+	delta = -1;
1591	+	Node<V> en = e.next;
1592	+	if (pred != null)
1593	+	pred.next = en;
1594	+	else
1595	+	setTabAt(tab, i, en);
1596	+	}
1597	+	break;
1598	+	}
1599	+	pred = e;
1600	+	if ((e = e.next) == null) {
1601	+	val = v;
1602	+	pred.next = new Node<V>(h, k, val, null);
1603	+	delta = 1;
1604	+	if (len >= TREE_THRESHOLD)
1605	+	replaceWithTreeBin(tab, i, k);
1606	+	break;
1607	+	}
1608	+	}
1609		}
1610		}
1611	<	} finally {
1612	<	unlock();
1611	>	if (len != 0)
1612	>	break;
1613		}
578	–	return replaced;
1614		}
1615	<
1616	<	final V replace(K key, int hash, V value) {
1617	<	if (!tryLock())
1618	<	scanAndLock(key, hash);
1619	<	V oldValue = null;
1620	<	try {
1621	<	HashEntry<K,V> e;
1622	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1623	<	K k;
1624	<	if ((k = e.key) == key ||
1625	<	(e.hash == hash && key.equals(k))) {
1626	<	oldValue = e.value;
1627	<	e.value = value;
1628	<	++modCount;
1629	<	break;
1615	>	if (delta != 0)
1616	>	addCount((long)delta, len);
1617	>	return val;
1618	>	}
1619	>
1620	>	/** Implementation for putAll */
1621	>	@SuppressWarnings("unchecked") private final void internalPutAll
1622	>	(Map<? extends K, ? extends V> m) {
1623	>	tryPresize(m.size());
1624	>	long delta = 0L;     // number of uncommitted additions
1625	>	boolean npe = false; // to throw exception on exit for nulls
1626	>	try {                // to clean up counts on other exceptions
1627	>	for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
1628	>	Object k; V v;
1629	>	if (entry == null || (k = entry.getKey()) == null ||
1630	>	(v = entry.getValue()) == null) {
1631	>	npe = true;
1632	>	break;
1633	>	}
1634	>	int h = spread(k.hashCode());
1635	>	for (Node<V>[] tab = table;;) {
1636	>	int i; Node<V> f; int fh; Object fk;
1637	>	if (tab == null)
1638	>	tab = initTable();
1639	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1640	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1641	>	++delta;
1642	>	break;
1643	>	}
1644	>	}
1645	>	else if ((fh = f.hash) < 0) {
1646	>	if ((fk = f.key) instanceof TreeBin) {
1647	>	TreeBin<V> t = (TreeBin<V>)fk;
1648	>	boolean validated = false;
1649	>	t.acquire(0);
1650	>	try {
1651	>	if (tabAt(tab, i) == f) {
1652	>	validated = true;
1653	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1654	>	if (p != null)
1655	>	p.val = v;
1656	>	else {
1657	>	t.putTreeNode(h, k, v);
1658	>	++delta;
1659	>	}
1660	>	}
1661	>	} finally {
1662	>	t.release(0);
1663	>	}
1664	>	if (validated)
1665	>	break;
1666	>	}
1667	>	else
1668	>	tab = (Node<V>[])fk;
1669	>	}
1670	>	else {
1671	>	int len = 0;
1672	>	synchronized (f) {
1673	>	if (tabAt(tab, i) == f) {
1674	>	len = 1;
1675	>	for (Node<V> e = f;; ++len) {
1676	>	Object ek; V ev;
1677	>	if (e.hash == h &&
1678	>	(ev = e.val) != null &&
1679	>	((ek = e.key) == k || k.equals(ek))) {
1680	>	e.val = v;
1681	>	break;
1682	>	}
1683	>	Node<V> last = e;
1684	>	if ((e = e.next) == null) {
1685	>	++delta;
1686	>	last.next = new Node<V>(h, k, v, null);
1687	>	if (len >= TREE_THRESHOLD)
1688	>	replaceWithTreeBin(tab, i, k);
1689	>	break;
1690	>	}
1691	>	}
1692	>	}
1693	>	}
1694	>	if (len != 0) {
1695	>	if (len > 1) {
1696	>	addCount(delta, len);
1697	>	delta = 0L;
1698	>	}
1699	>	break;
1700	>	}
1701		}
1702		}
597	–	} finally {
598	–	unlock();
1703		}
1704	<	return oldValue;
1704	>	} finally {
1705	>	if (delta != 0L)
1706	>	addCount(delta, 2);
1707		}
1708	+	if (npe)
1709	+	throw new NullPointerException();
1710	+	}
1711
1712	<	final void clear() {
1713	<	lock();
1714	<	try {
1715	<	HashEntry<K,V>[] tab = table;
1716	<	for (int i = 0; i < tab.length ; i++)
1717	<	setEntryAt(tab, i, null);
1718	<	++modCount;
1719	<	count = 0;
1720	<	} finally {
1721	<	unlock();
1712	>	/**
1713	>	* Implementation for clear. Steps through each bin, removing all
1714	>	* nodes.
1715	>	*/
1716	>	@SuppressWarnings("unchecked") private final void internalClear() {
1717	>	long delta = 0L; // negative number of deletions
1718	>	int i = 0;
1719	>	Node<V>[] tab = table;
1720	>	while (tab != null && i < tab.length) {
1721	>	Node<V> f = tabAt(tab, i);
1722	>	if (f == null)
1723	>	++i;
1724	>	else if (f.hash < 0) {
1725	>	Object fk;
1726	>	if ((fk = f.key) instanceof TreeBin) {
1727	>	TreeBin<V> t = (TreeBin<V>)fk;
1728	>	t.acquire(0);
1729	>	try {
1730	>	if (tabAt(tab, i) == f) {
1731	>	for (Node<V> p = t.first; p != null; p = p.next) {
1732	>	if (p.val != null) { // (currently always true)
1733	>	p.val = null;
1734	>	--delta;
1735	>	}
1736	>	}
1737	>	t.first = null;
1738	>	t.root = null;
1739	>	++i;
1740	>	}
1741	>	} finally {
1742	>	t.release(0);
1743	>	}
1744	>	}
1745	>	else
1746	>	tab = (Node<V>[])fk;
1747	>	}
1748	>	else {
1749	>	synchronized (f) {
1750	>	if (tabAt(tab, i) == f) {
1751	>	for (Node<V> e = f; e != null; e = e.next) {
1752	>	if (e.val != null) {  // (currently always true)
1753	>	e.val = null;
1754	>	--delta;
1755	>	}
1756	>	}
1757	>	setTabAt(tab, i, null);
1758	>	++i;
1759	>	}
1760	>	}
1761		}
1762		}
1763	+	if (delta != 0L)
1764	+	addCount(delta, -1);
1765		}
1766
1767	<	// Accessing segments
1768	<
1769	<	/**
1770	<	* Gets the jth element of given segment array (if nonnull) with
1771	<	* volatile element access semantics via Unsafe. (The null check
1772	<	* can trigger harmlessly only during deserialization.) Note:
1773	<	* because each element of segments array is set only once (using
1774	<	* fully ordered writes), some performance-sensitive methods rely
1775	<	* on this method only as a recheck upon null reads.
1776	<	*/
1777	<	@SuppressWarnings("unchecked")
1778	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
1779	<	long u = (j << SSHIFT) + SBASE;
1780	<	return ss == null ? null :
631	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
1767	>	/* ---------------- Table Initialization and Resizing -------------- */
1768	>
1769	>	/**
1770	>	* Returns a power of two table size for the given desired capacity.
1771	>	* See Hackers Delight, sec 3.2
1772	>	*/
1773	>	private static final int tableSizeFor(int c) {
1774	>	int n = c - 1;
1775	>	n |= n >>> 1;
1776	>	n |= n >>> 2;
1777	>	n |= n >>> 4;
1778	>	n |= n >>> 8;
1779	>	n |= n >>> 16;
1780	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1781		}
1782
1783		/**
1784	<	* Returns the segment for the given index, creating it and
1785	<	* recording in segment table (via CAS) if not already present.
1786	<	*
1787	<	* @param k the index
1788	<	* @return the segment
1789	<	*/
1790	<	@SuppressWarnings("unchecked")
1791	<	private Segment<K,V> ensureSegment(int k) {
1792	<	final Segment<K,V>[] ss = this.segments;
1793	<	long u = (k << SSHIFT) + SBASE; // raw offset
1794	<	Segment<K,V> seg;
1795	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
1796	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
1797	<	int cap = proto.table.length;
1798	<	float lf = proto.loadFactor;
1799	<	int threshold = (int)(cap * lf);
1800	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry[cap];
652	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
653	<	== null) { // recheck
654	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
655	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
656	<	== null) {
657	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
658	<	break;
1784	>	* Initializes table, using the size recorded in sizeCtl.
1785	>	*/
1786	>	@SuppressWarnings("unchecked") private final Node<V>[] initTable() {
1787	>	Node<V>[] tab; int sc;
1788	>	while ((tab = table) == null) {
1789	>	if ((sc = sizeCtl) < 0)
1790	>	Thread.yield(); // lost initialization race; just spin
1791	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1792	>	try {
1793	>	if ((tab = table) == null) {
1794	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1795	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1796	>	table = tab = (Node<V>[])tb;
1797	>	sc = n - (n >>> 2);
1798	>	}
1799	>	} finally {
1800	>	sizeCtl = sc;
1801		}
1802	+	break;
1803		}
1804		}
1805	<	return seg;
1805	>	return tab;
1806		}
1807
1808	<	// Hash-based segment and entry accesses
1808	>	/**
1809	>	* Adds to count, and if table is too small and not already
1810	>	* resizing, initiates transfer. If already resizing, helps
1811	>	* perform transfer if work is available.  Rechecks occupancy
1812	>	* after a transfer to see if another resize is already needed
1813	>	* because resizings are lagging additions.
1814	>	*
1815	>	* @param x the count to add
1816	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
1817	>	*/
1818	>	private final void addCount(long x, int check) {
1819	>	Cell[] as; long b, s;
1820	>	if ((as = counterCells) != null ||
1821	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
1822	>	Cell a; long v; int m;
1823	>	boolean uncontended = true;
1824	>	if (as == null || (m = as.length - 1) < 0 ||
1825	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
1826	>	!(uncontended =
1827	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
1828	>	fullAddCount(x, uncontended);
1829	>	return;
1830	>	}
1831	>	if (check <= 1)
1832	>	return;
1833	>	s = sumCount();
1834	>	}
1835	>	if (check >= 0) {
1836	>	Node<V>[] tab, nt; int sc;
1837	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
1838	>	tab.length < MAXIMUM_CAPACITY) {
1839	>	if (sc < 0) {
1840	>	if (sc == -1 || transferIndex <= transferOrigin ||
1841	>	(nt = nextTable) == null)
1842	>	break;
1843	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
1844	>	transfer(tab, nt);
1845	>	}
1846	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
1847	>	transfer(tab, null);
1848	>	s = sumCount();
1849	>	}
1850	>	}
1851	>	}
1852
1853		/**
1854	<	* Gets the segment for the given hash code.
1854	>	* Tries to presize table to accommodate the given number of elements.
1855	>	*
1856	>	* @param size number of elements (doesn't need to be perfectly accurate)
1857		*/
1858	<	@SuppressWarnings("unchecked")
1859	<	private Segment<K,V> segmentForHash(int h) {
1860	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1861	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
1858	>	@SuppressWarnings("unchecked") private final void tryPresize(int size) {
1859	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1860	>	tableSizeFor(size + (size >>> 1) + 1);
1861	>	int sc;
1862	>	while ((sc = sizeCtl) >= 0) {
1863	>	Node<V>[] tab = table; int n;
1864	>	if (tab == null || (n = tab.length) == 0) {
1865	>	n = (sc > c) ? sc : c;
1866	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1867	>	try {
1868	>	if (table == tab) {
1869	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1870	>	table = (Node<V>[])tb;
1871	>	sc = n - (n >>> 2);
1872	>	}
1873	>	} finally {
1874	>	sizeCtl = sc;
1875	>	}
1876	>	}
1877	>	}
1878	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1879	>	break;
1880	>	else if (tab == table &&
1881	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
1882	>	transfer(tab, null);
1883	>	}
1884		}
1885
1886		/**
1887	<	* Gets the table entry for the given segment and hash code.
1887	>	* Moves and/or copies the nodes in each bin to new table. See
1888	>	* above for explanation.
1889		*/
1890	<	@SuppressWarnings("unchecked")
1891	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
1892	<	HashEntry<K,V>[] tab;
1893	<	return (seg == null || (tab = seg.table) == null) ? null :
1894	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
1895	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1890	>	@SuppressWarnings("unchecked") private final void transfer
1891	>	(Node<V>[] tab, Node<V>[] nextTab) {
1892	>	int n = tab.length, stride;
1893	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
1894	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
1895	>	if (nextTab == null) {            // initiating
1896	>	try {
1897	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n << 1];
1898	>	nextTab = (Node<V>[])tb;
1899	>	} catch (Throwable ex) {      // try to cope with OOME
1900	>	sizeCtl = Integer.MAX_VALUE;
1901	>	return;
1902	>	}
1903	>	nextTable = nextTab;
1904	>	transferOrigin = n;
1905	>	transferIndex = n;
1906	>	Node<V> rev = new Node<V>(MOVED, tab, null, null);
1907	>	for (int k = n; k > 0;) {    // progressively reveal ready slots
1908	>	int nextk = (k > stride) ? k - stride : 0;
1909	>	for (int m = nextk; m < k; ++m)
1910	>	nextTab[m] = rev;
1911	>	for (int m = n + nextk; m < n + k; ++m)
1912	>	nextTab[m] = rev;
1913	>	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
1914	>	}
1915	>	}
1916	>	int nextn = nextTab.length;
1917	>	Node<V> fwd = new Node<V>(MOVED, nextTab, null, null);
1918	>	boolean advance = true;
1919	>	for (int i = 0, bound = 0;;) {
1920	>	int nextIndex, nextBound; Node<V> f; Object fk;
1921	>	while (advance) {
1922	>	if (--i >= bound)
1923	>	advance = false;
1924	>	else if ((nextIndex = transferIndex) <= transferOrigin) {
1925	>	i = -1;
1926	>	advance = false;
1927	>	}
1928	>	else if (U.compareAndSwapInt
1929	>	(this, TRANSFERINDEX, nextIndex,
1930	>	nextBound = (nextIndex > stride ?
1931	>	nextIndex - stride : 0))) {
1932	>	bound = nextBound;
1933	>	i = nextIndex - 1;
1934	>	advance = false;
1935	>	}
1936	>	}
1937	>	if (i < 0 || i >= n || i + n >= nextn) {
1938	>	for (int sc;;) {
1939	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
1940	>	if (sc == -1) {
1941	>	nextTable = null;
1942	>	table = nextTab;
1943	>	sizeCtl = (n << 1) - (n >>> 1);
1944	>	}
1945	>	return;
1946	>	}
1947	>	}
1948	>	}
1949	>	else if ((f = tabAt(tab, i)) == null) {
1950	>	if (casTabAt(tab, i, null, fwd)) {
1951	>	setTabAt(nextTab, i, null);
1952	>	setTabAt(nextTab, i + n, null);
1953	>	advance = true;
1954	>	}
1955	>	}
1956	>	else if (f.hash >= 0) {
1957	>	synchronized (f) {
1958	>	if (tabAt(tab, i) == f) {
1959	>	int runBit = f.hash & n;
1960	>	Node<V> lastRun = f, lo = null, hi = null;
1961	>	for (Node<V> p = f.next; p != null; p = p.next) {
1962	>	int b = p.hash & n;
1963	>	if (b != runBit) {
1964	>	runBit = b;
1965	>	lastRun = p;
1966	>	}
1967	>	}
1968	>	if (runBit == 0)
1969	>	lo = lastRun;
1970	>	else
1971	>	hi = lastRun;
1972	>	for (Node<V> p = f; p != lastRun; p = p.next) {
1973	>	int ph = p.hash;
1974	>	Object pk = p.key; V pv = p.val;
1975	>	if ((ph & n) == 0)
1976	>	lo = new Node<V>(ph, pk, pv, lo);
1977	>	else
1978	>	hi = new Node<V>(ph, pk, pv, hi);
1979	>	}
1980	>	setTabAt(nextTab, i, lo);
1981	>	setTabAt(nextTab, i + n, hi);
1982	>	setTabAt(tab, i, fwd);
1983	>	advance = true;
1984	>	}
1985	>	}
1986	>	}
1987	>	else if ((fk = f.key) instanceof TreeBin) {
1988	>	TreeBin<V> t = (TreeBin<V>)fk;
1989	>	t.acquire(0);
1990	>	try {
1991	>	if (tabAt(tab, i) == f) {
1992	>	TreeBin<V> lt = new TreeBin<V>();
1993	>	TreeBin<V> ht = new TreeBin<V>();
1994	>	int lc = 0, hc = 0;
1995	>	for (Node<V> e = t.first; e != null; e = e.next) {
1996	>	int h = e.hash;
1997	>	Object k = e.key; V v = e.val;
1998	>	if ((h & n) == 0) {
1999	>	++lc;
2000	>	lt.putTreeNode(h, k, v);
2001	>	}
2002	>	else {
2003	>	++hc;
2004	>	ht.putTreeNode(h, k, v);
2005	>	}
2006	>	}
2007	>	Node<V> ln, hn; // throw away trees if too small
2008	>	if (lc < TREE_THRESHOLD) {
2009	>	ln = null;
2010	>	for (Node<V> p = lt.first; p != null; p = p.next)
2011	>	ln = new Node<V>(p.hash, p.key, p.val, ln);
2012	>	}
2013	>	else
2014	>	ln = new Node<V>(MOVED, lt, null, null);
2015	>	setTabAt(nextTab, i, ln);
2016	>	if (hc < TREE_THRESHOLD) {
2017	>	hn = null;
2018	>	for (Node<V> p = ht.first; p != null; p = p.next)
2019	>	hn = new Node<V>(p.hash, p.key, p.val, hn);
2020	>	}
2021	>	else
2022	>	hn = new Node<V>(MOVED, ht, null, null);
2023	>	setTabAt(nextTab, i + n, hn);
2024	>	setTabAt(tab, i, fwd);
2025	>	advance = true;
2026	>	}
2027	>	} finally {
2028	>	t.release(0);
2029	>	}
2030	>	}
2031	>	else
2032	>	advance = true; // already processed
2033	>	}
2034		}
2035
2036	<	/* ---------------- Public operations -------------- */
2036	>	/* ---------------- Counter support -------------- */
2037	>
2038	>	final long sumCount() {
2039	>	Cell[] as = counterCells; Cell a;
2040	>	long sum = baseCount;
2041	>	if (as != null) {
2042	>	for (int i = 0; i < as.length; ++i) {
2043	>	if ((a = as[i]) != null)
2044	>	sum += a.value;
2045	>	}
2046	>	}
2047	>	return sum;
2048	>	}
2049	>
2050	>	// See LongAdder version for explanation
2051	>	private final void fullAddCount(long x, boolean wasUncontended) {
2052	>	int h;
2053	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2054	>	ThreadLocalRandom.localInit();      // force initialization
2055	>	h = ThreadLocalRandom.getProbe();
2056	>	wasUncontended = true;
2057	>	}
2058	>	boolean collide = false;                // True if last slot nonempty
2059	>	for (;;) {
2060	>	Cell[] as; Cell a; int n; long v;
2061	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2062	>	if ((a = as[(n - 1) & h]) == null) {
2063	>	if (cellsBusy == 0) {            // Try to attach new Cell
2064	>	Cell r = new Cell(x); // Optimistic create
2065	>	if (cellsBusy == 0 &&
2066	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2067	>	boolean created = false;
2068	>	try {               // Recheck under lock
2069	>	Cell[] rs; int m, j;
2070	>	if ((rs = counterCells) != null &&
2071	>	(m = rs.length) > 0 &&
2072	>	rs[j = (m - 1) & h] == null) {
2073	>	rs[j] = r;
2074	>	created = true;
2075	>	}
2076	>	} finally {
2077	>	cellsBusy = 0;
2078	>	}
2079	>	if (created)
2080	>	break;
2081	>	continue;           // Slot is now non-empty
2082	>	}
2083	>	}
2084	>	collide = false;
2085	>	}
2086	>	else if (!wasUncontended)       // CAS already known to fail
2087	>	wasUncontended = true;      // Continue after rehash
2088	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2089	>	break;
2090	>	else if (counterCells != as || n >= NCPU)
2091	>	collide = false;            // At max size or stale
2092	>	else if (!collide)
2093	>	collide = true;
2094	>	else if (cellsBusy == 0 &&
2095	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2096	>	try {
2097	>	if (counterCells == as) {// Expand table unless stale
2098	>	Cell[] rs = new Cell[n << 1];
2099	>	for (int i = 0; i < n; ++i)
2100	>	rs[i] = as[i];
2101	>	counterCells = rs;
2102	>	}
2103	>	} finally {
2104	>	cellsBusy = 0;
2105	>	}
2106	>	collide = false;
2107	>	continue;                   // Retry with expanded table
2108	>	}
2109	>	h = ThreadLocalRandom.advanceProbe(h);
2110	>	}
2111	>	else if (cellsBusy == 0 && counterCells == as &&
2112	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2113	>	boolean init = false;
2114	>	try {                           // Initialize table
2115	>	if (counterCells == as) {
2116	>	Cell[] rs = new Cell[2];
2117	>	rs[h & 1] = new Cell(x);
2118	>	counterCells = rs;
2119	>	init = true;
2120	>	}
2121	>	} finally {
2122	>	cellsBusy = 0;
2123	>	}
2124	>	if (init)
2125	>	break;
2126	>	}
2127	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2128	>	break;                          // Fall back on using base
2129	>	}
2130	>	}
2131	>
2132	>	/* ----------------Table Traversal -------------- */
2133
2134		/**
2135	<	* Creates a new, empty map with the specified initial
2136	<	* capacity, load factor and concurrency level.
2135	>	* Encapsulates traversal for methods such as containsValue; also
2136	>	* serves as a base class for other iterators and bulk tasks.
2137		*
2138	<	* @param initialCapacity the initial capacity. The implementation
2139	<	* performs internal sizing to accommodate this many elements.
2140	<	* @param loadFactor  the load factor threshold, used to control resizing.
2141	<	* Resizing may be performed when the average number of elements per
2142	<	* bin exceeds this threshold.
2143	<	* @param concurrencyLevel the estimated number of concurrently
2144	<	* updating threads. The implementation performs internal sizing
2145	<	* to try to accommodate this many threads.
2146	<	* @throws IllegalArgumentException if the initial capacity is
2147	<	* negative or the load factor or concurrencyLevel are
2148	<	* nonpositive.
2138	>	* At each step, the iterator snapshots the key ("nextKey") and
2139	>	* value ("nextVal") of a valid node (i.e., one that, at point of
2140	>	* snapshot, has a non-null user value). Because val fields can
2141	>	* change (including to null, indicating deletion), field nextVal
2142	>	* might not be accurate at point of use, but still maintains the
2143	>	* weak consistency property of holding a value that was once
2144	>	* valid. To support iterator.remove, the nextKey field is not
2145	>	* updated (nulled out) when the iterator cannot advance.
2146	>	*
2147	>	* Internal traversals directly access these fields, as in:
2148	>	* {@code while (it.advance() != null) { process(it.nextKey); }}
2149	>	*
2150	>	* Exported iterators must track whether the iterator has advanced
2151	>	* (in hasNext vs next) (by setting/checking/nulling field
2152	>	* nextVal), and then extract key, value, or key-value pairs as
2153	>	* return values of next().
2154	>	*
2155	>	* The iterator visits once each still-valid node that was
2156	>	* reachable upon iterator construction. It might miss some that
2157	>	* were added to a bin after the bin was visited, which is OK wrt
2158	>	* consistency guarantees. Maintaining this property in the face
2159	>	* of possible ongoing resizes requires a fair amount of
2160	>	* bookkeeping state that is difficult to optimize away amidst
2161	>	* volatile accesses.  Even so, traversal maintains reasonable
2162	>	* throughput.
2163	>	*
2164	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2165	>	* However, if the table has been resized, then all future steps
2166	>	* must traverse both the bin at the current index as well as at
2167	>	* (index + baseSize); and so on for further resizings. To
2168	>	* paranoically cope with potential sharing by users of iterators
2169	>	* across threads, iteration terminates if a bounds checks fails
2170	>	* for a table read.
2171	>	*
2172	>	* This class supports both Spliterator-based traversal and
2173	>	* CountedCompleter-based bulk tasks. The same "batch" field is
2174	>	* used, but in slightly different ways, in the two cases.  For
2175	>	* Spliterators, it is a saturating (at Integer.MAX_VALUE)
2176	>	* estimate of element coverage. For CHM tasks, it is a pre-scaled
2177	>	* size that halves down to zero for leaf tasks, that is only
2178	>	* computed upon execution of the task. (Tasks can be submitted to
2179	>	* any pool, of any size, so we don't know scale factors until
2180	>	* running.)
2181	>	*
2182	>	* This class extends CountedCompleter to streamline parallel
2183	>	* iteration in bulk operations. This adds only a few fields of
2184	>	* space overhead, which is small enough in cases where it is not
2185	>	* needed to not worry about it.  Because CountedCompleter is
2186	>	* Serializable, but iterators need not be, we need to add warning
2187	>	* suppressions.
2188	>	*/
2189	>	@SuppressWarnings("serial") static class Traverser<K,V,R>
2190	>	extends CountedCompleter<R> {
2191	>	final ConcurrentHashMap<K,V> map;
2192	>	Node<V> next;        // the next entry to use
2193	>	K nextKey;           // cached key field of next
2194	>	V nextVal;           // cached val field of next
2195	>	Node<V>[] tab;       // current table; updated if resized
2196	>	int index;           // index of bin to use next
2197	>	int baseIndex;       // current index of initial table
2198	>	int baseLimit;       // index bound for initial table
2199	>	int baseSize;        // initial table size
2200	>	int batch;           // split control
2201	>	/** Creates iterator for all entries in the table. */
2202	>	Traverser(ConcurrentHashMap<K,V> map) {
2203	>	this.map = map;
2204	>	Node<V>[] t;
2205	>	if ((t = tab = map.table) != null)
2206	>	baseLimit = baseSize = t.length;
2207	>	}
2208	>
2209	>	/** Task constructor */
2210	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it, int batch) {
2211	>	super(it);
2212	>	this.map = map;
2213	>	this.batch = batch; // -1 if unknown
2214	>	if (it == null) {
2215	>	Node<V>[] t;
2216	>	if ((t = tab = map.table) != null)
2217	>	baseLimit = baseSize = t.length;
2218	>	}
2219	>	else { // split parent
2220	>	this.tab = it.tab;
2221	>	this.baseSize = it.baseSize;
2222	>	int hi = this.baseLimit = it.baseLimit;
2223	>	it.baseLimit = this.index = this.baseIndex =
2224	>	(hi + it.baseIndex + 1) >>> 1;
2225	>	}
2226	>	}
2227	>
2228	>	/** Spliterator constructor */
2229	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it) {
2230	>	super(it);
2231	>	this.map = map;
2232	>	if (it == null) {
2233	>	Node<V>[] t;
2234	>	if ((t = tab = map.table) != null)
2235	>	baseLimit = baseSize = t.length;
2236	>	long n = map.sumCount();
2237	>	batch = ((n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2238	>	(int)n);
2239	>	}
2240	>	else {
2241	>	this.tab = it.tab;
2242	>	this.baseSize = it.baseSize;
2243	>	int hi = this.baseLimit = it.baseLimit;
2244	>	it.baseLimit = this.index = this.baseIndex =
2245	>	(hi + it.baseIndex + 1) >>> 1;
2246	>	this.batch = it.batch >>>= 1;
2247	>	}
2248	>	}
2249	>
2250	>	/**
2251	>	* Advances next; returns nextVal or null if terminated.
2252	>	* See above for explanation.
2253	>	*/
2254	>	@SuppressWarnings("unchecked") final V advance() {
2255	>	Node<V> e = next;
2256	>	V ev = null;
2257	>	outer: do {
2258	>	if (e != null)                  // advance past used/skipped node
2259	>	e = e.next;
2260	>	while (e == null) {             // get to next non-null bin
2261	>	ConcurrentHashMap<K,V> m;
2262	>	Node<V>[] t; int b, i, n; Object ek; //  must use locals
2263	>	if ((t = tab) != null)
2264	>	n = t.length;
2265	>	else if ((m = map) != null && (t = tab = m.table) != null)
2266	>	n = baseLimit = baseSize = t.length;
2267	>	else
2268	>	break outer;
2269	>	if ((b = baseIndex) >= baseLimit ||
2270	>	(i = index) < 0 || i >= n)
2271	>	break outer;
2272	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2273	>	if ((ek = e.key) instanceof TreeBin)
2274	>	e = ((TreeBin<V>)ek).first;
2275	>	else {
2276	>	tab = (Node<V>[])ek;
2277	>	continue;           // restarts due to null val
2278	>	}
2279	>	}                           // visit upper slots if present
2280	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2281	>	}
2282	>	nextKey = (K)e.key;
2283	>	} while ((ev = e.val) == null);    // skip deleted or special nodes
2284	>	next = e;
2285	>	return nextVal = ev;
2286	>	}
2287	>
2288	>	public final void remove() {
2289	>	K k = nextKey;
2290	>	if (k == null && (advance() == null || (k = nextKey) == null))
2291	>	throw new IllegalStateException();
2292	>	map.internalReplace(k, null, null);
2293	>	}
2294	>
2295	>	public final boolean hasNext() {
2296	>	return nextVal != null || advance() != null;
2297	>	}
2298	>
2299	>	public final boolean hasMoreElements() { return hasNext(); }
2300	>
2301	>	public void compute() { } // default no-op CountedCompleter body
2302	>
2303	>	/**
2304	>	* Returns a batch value > 0 if this task should (and must) be
2305	>	* split, if so, adding to pending count, and in any case
2306	>	* updating batch value. The initial batch value is approx
2307	>	* exp2 of the number of times (minus one) to split task by
2308	>	* two before executing leaf action. This value is faster to
2309	>	* compute and more convenient to use as a guide to splitting
2310	>	* than is the depth, since it is used while dividing by two
2311	>	* anyway.
2312	>	*/
2313	>	final int preSplit() {
2314	>	int b;  ForkJoinPool pool;
2315	>	if ((b = batch) < 0) { // force initialization
2316	>	int sp = (((pool = getPool()) == null) ?
2317	>	ForkJoinPool.getCommonPoolParallelism() :
2318	>	pool.getParallelism()) << 3; // slack of 8
2319	>	long n = map.sumCount();
2320	>	b = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
2321	>	}
2322	>	b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
2323	>	if ((batch = b) > 0)
2324	>	addToPendingCount(1);
2325	>	return b;
2326	>	}
2327	>
2328	>	// spliterator support
2329	>
2330	>	public boolean hasExactSize() {
2331	>	return false;
2332	>	}
2333	>
2334	>	public boolean hasExactSplits() {
2335	>	return false;
2336	>	}
2337	>
2338	>	public long estimateSize() {
2339	>	return batch;
2340	>	}
2341	>	}
2342	>
2343	>	/* ---------------- Public operations -------------- */
2344	>
2345	>	/**
2346	>	* Creates a new, empty map with the default initial table size (16).
2347		*/
2348	<	@SuppressWarnings("unchecked")
706	<	public ConcurrentHashMap(int initialCapacity,
707	<	float loadFactor, int concurrencyLevel) {
708	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
709	<	throw new IllegalArgumentException();
710	<	if (concurrencyLevel > MAX_SEGMENTS)
711	<	concurrencyLevel = MAX_SEGMENTS;
712	<	// Find power-of-two sizes best matching arguments
713	<	int sshift = 0;
714	<	int ssize = 1;
715	<	while (ssize < concurrencyLevel) {
716	<	++sshift;
717	<	ssize <<= 1;
718	<	}
719	<	this.segmentShift = 32 - sshift;
720	<	this.segmentMask = ssize - 1;
721	<	if (initialCapacity > MAXIMUM_CAPACITY)
722	<	initialCapacity = MAXIMUM_CAPACITY;
723	<	int c = initialCapacity / ssize;
724	<	if (c * ssize < initialCapacity)
725	<	++c;
726	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
727	<	while (cap < c)
728	<	cap <<= 1;
729	<	// create segments and segments[0]
730	<	Segment<K,V> s0 =
731	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
732	<	(HashEntry<K,V>[])new HashEntry[cap]);
733	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment[ssize];
734	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
735	<	this.segments = ss;
2348	>	public ConcurrentHashMap() {
2349		}
2350
2351		/**
2352	<	* Creates a new, empty map with the specified initial capacity
2353	<	* and load factor and with the default concurrencyLevel (16).
2352	>	* Creates a new, empty map with an initial table size
2353	>	* accommodating the specified number of elements without the need
2354	>	* to dynamically resize.
2355		*
2356		* @param initialCapacity The implementation performs internal
2357		* sizing to accommodate this many elements.
2358	<	* @param loadFactor  the load factor threshold, used to control resizing.
2359	<	* Resizing may be performed when the average number of elements per
2360	<	* bin exceeds this threshold.
2358	>	* @throws IllegalArgumentException if the initial capacity of
2359	>	* elements is negative
2360	>	*/
2361	>	public ConcurrentHashMap(int initialCapacity) {
2362	>	if (initialCapacity < 0)
2363	>	throw new IllegalArgumentException();
2364	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2365	>	MAXIMUM_CAPACITY :
2366	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2367	>	this.sizeCtl = cap;
2368	>	}
2369	>
2370	>	/**
2371	>	* Creates a new map with the same mappings as the given map.
2372	>	*
2373	>	* @param m the map
2374	>	*/
2375	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2376	>	this.sizeCtl = DEFAULT_CAPACITY;
2377	>	internalPutAll(m);
2378	>	}
2379	>
2380	>	/**
2381	>	* Creates a new, empty map with an initial table size based on
2382	>	* the given number of elements ({@code initialCapacity}) and
2383	>	* initial table density ({@code loadFactor}).
2384	>	*
2385	>	* @param initialCapacity the initial capacity. The implementation
2386	>	* performs internal sizing to accommodate this many elements,
2387	>	* given the specified load factor.
2388	>	* @param loadFactor the load factor (table density) for
2389	>	* establishing the initial table size
2390		* @throws IllegalArgumentException if the initial capacity of
2391		* elements is negative or the load factor is nonpositive
2392		*
2393		* @since 1.6
2394		*/
2395		public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2396	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2396	>	this(initialCapacity, loadFactor, 1);
2397		}
2398
2399		/**
2400	<	* Creates a new, empty map with the specified initial capacity,
2401	<	* and with default load factor (0.75) and concurrencyLevel (16).
2400	>	* Creates a new, empty map with an initial table size based on
2401	>	* the given number of elements ({@code initialCapacity}), table
2402	>	* density ({@code loadFactor}), and number of concurrently
2403	>	* updating threads ({@code concurrencyLevel}).
2404		*
2405		* @param initialCapacity the initial capacity. The implementation
2406	<	* performs internal sizing to accommodate this many elements.
2407	<	* @throws IllegalArgumentException if the initial capacity of
2408	<	* elements is negative.
2406	>	* performs internal sizing to accommodate this many elements,
2407	>	* given the specified load factor.
2408	>	* @param loadFactor the load factor (table density) for
2409	>	* establishing the initial table size
2410	>	* @param concurrencyLevel the estimated number of concurrently
2411	>	* updating threads. The implementation may use this value as
2412	>	* a sizing hint.
2413	>	* @throws IllegalArgumentException if the initial capacity is
2414	>	* negative or the load factor or concurrencyLevel are
2415	>	* nonpositive
2416		*/
2417	<	public ConcurrentHashMap(int initialCapacity) {
2418	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2417	>	public ConcurrentHashMap(int initialCapacity,
2418	>	float loadFactor, int concurrencyLevel) {
2419	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2420	>	throw new IllegalArgumentException();
2421	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2422	>	initialCapacity = concurrencyLevel;   // as estimated threads
2423	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2424	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2425	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
2426	>	this.sizeCtl = cap;
2427		}
2428
2429		/**
2430	<	* Creates a new, empty map with a default initial capacity (16),
2431	<	* load factor (0.75) and concurrencyLevel (16).
2430	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2431	>	* from the given type to {@code Boolean.TRUE}.
2432	>	*
2433	>	* @return the new set
2434		*/
2435	<	public ConcurrentHashMap() {
2436	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2435	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2436	>	return new KeySetView<K,Boolean>
2437	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2438		}
2439
2440		/**
2441	<	* Creates a new map with the same mappings as the given map.
2442	<	* The map is created with a capacity of 1.5 times the number
780	<	* of mappings in the given map or 16 (whichever is greater),
781	<	* and a default load factor (0.75) and concurrencyLevel (16).
2441	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2442	>	* from the given type to {@code Boolean.TRUE}.
2443		*
2444	<	* @param m the map
2444	>	* @param initialCapacity The implementation performs internal
2445	>	* sizing to accommodate this many elements.
2446	>	* @throws IllegalArgumentException if the initial capacity of
2447	>	* elements is negative
2448	>	* @return the new set
2449		*/
2450	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2451	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
2452	<	DEFAULT_INITIAL_CAPACITY),
788	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
789	<	putAll(m);
2450	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2451	>	return new KeySetView<K,Boolean>
2452	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2453		}
2454
2455		/**
2456	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
794	<	*
795	<	* @return <tt>true</tt> if this map contains no key-value mappings
2456	>	* {@inheritDoc}
2457		*/
2458		public boolean isEmpty() {
2459	<	/*
799	<	* Sum per-segment modCounts to avoid mis-reporting when
800	<	* elements are concurrently added and removed in one segment
801	<	* while checking another, in which case the table was never
802	<	* actually empty at any point. (The sum ensures accuracy up
803	<	* through at least 1<<31 per-segment modifications before
804	<	* recheck.)  Methods size() and containsValue() use similar
805	<	* constructions for stability checks.
806	<	*/
807	<	long sum = 0L;
808	<	final Segment<K,V>[] segments = this.segments;
809	<	for (int j = 0; j < segments.length; ++j) {
810	<	Segment<K,V> seg = segmentAt(segments, j);
811	<	if (seg != null) {
812	<	if (seg.count != 0)
813	<	return false;
814	<	sum += seg.modCount;
815	<	}
816	<	}
817	<	if (sum != 0L) { // recheck unless no modifications
818	<	for (int j = 0; j < segments.length; ++j) {
819	<	Segment<K,V> seg = segmentAt(segments, j);
820	<	if (seg != null) {
821	<	if (seg.count != 0)
822	<	return false;
823	<	sum -= seg.modCount;
824	<	}
825	<	}
826	<	if (sum != 0L)
827	<	return false;
828	<	}
829	<	return true;
2459	>	return sumCount() <= 0L; // ignore transient negative values
2460		}
2461
2462		/**
2463	<	* Returns the number of key-value mappings in this map.  If the
834	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
835	<	* <tt>Integer.MAX_VALUE</tt>.
836	<	*
837	<	* @return the number of key-value mappings in this map
2463	>	* {@inheritDoc}
2464		*/
2465		public int size() {
2466	<	// Try a few times to get accurate count. On failure due to
2467	<	// continuous async changes in table, resort to locking.
2468	<	final Segment<K,V>[] segments = this.segments;
2469	<	int size;
2470	<	boolean overflow; // true if size overflows 32 bits
2471	<	long sum;         // sum of modCounts
2472	<	long last = 0L;   // previous sum
2473	<	int retries = -1; // first iteration isn't retry
2474	<	try {
2475	<	for (;;) {
2476	<	if (retries++ == RETRIES_BEFORE_LOCK) {
2477	<	for (int j = 0; j < segments.length; ++j)
2478	<	ensureSegment(j).lock(); // force creation
2479	<	}
2480	<	sum = 0L;
2481	<	size = 0;
2482	<	overflow = false;
2483	<	for (int j = 0; j < segments.length; ++j) {
858	<	Segment<K,V> seg = segmentAt(segments, j);
859	<	if (seg != null) {
860	<	sum += seg.modCount;
861	<	int c = seg.count;
862	<	if (c < 0 || (size += c) < 0)
863	<	overflow = true;
864	<	}
865	<	}
866	<	if (sum == last)
867	<	break;
868	<	last = sum;
869	<	}
870	<	} finally {
871	<	if (retries > RETRIES_BEFORE_LOCK) {
872	<	for (int j = 0; j < segments.length; ++j)
873	<	segmentAt(segments, j).unlock();
874	<	}
875	<	}
876	<	return overflow ? Integer.MAX_VALUE : size;
2466	>	long n = sumCount();
2467	>	return ((n < 0L) ? 0 :
2468	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2469	>	(int)n);
2470	>	}
2471	>
2472	>	/**
2473	>	* Returns the number of mappings. This method should be used
2474	>	* instead of {@link #size} because a ConcurrentHashMap may
2475	>	* contain more mappings than can be represented as an int. The
2476	>	* value returned is an estimate; the actual count may differ if
2477	>	* there are concurrent insertions or removals.
2478	>	*
2479	>	* @return the number of mappings
2480	>	*/
2481	>	public long mappingCount() {
2482	>	long n = sumCount();
2483	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2484		}
2485
2486		/**
#	Line 888 | Line 2495 | public class ConcurrentHashMap<K, V> ext
2495		* @throws NullPointerException if the specified key is null
2496		*/
2497		public V get(Object key) {
2498	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
2499	<	HashEntry<K,V>[] tab;
2500	<	int h = hash(key.hashCode());
2501	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2502	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
2503	<	(tab = s.table) != null) {
2504	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
2505	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2506	<	e != null; e = e.next) {
2507	<	K k;
2508	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
2509	<	return e.value;
2510	<	}
2511	<	}
2512	<	return null;
2498	>	return internalGet(key);
2499	>	}
2500	>
2501	>	/**
2502	>	* Returns the value to which the specified key is mapped,
2503	>	* or the given defaultValue if this map contains no mapping for the key.
2504	>	*
2505	>	* @param key the key
2506	>	* @param defaultValue the value to return if this map contains
2507	>	* no mapping for the given key
2508	>	* @return the mapping for the key, if present; else the defaultValue
2509	>	* @throws NullPointerException if the specified key is null
2510	>	*/
2511	>	public V getValueOrDefault(Object key, V defaultValue) {
2512	>	V v;
2513	>	return (v = internalGet(key)) == null ? defaultValue : v;
2514		}
2515
2516		/**
2517		* Tests if the specified object is a key in this table.
2518		*
2519		* @param  key   possible key
2520	<	* @return <tt>true</tt> if and only if the specified object
2520	>	* @return {@code true} if and only if the specified object
2521		*         is a key in this table, as determined by the
2522	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
2522	>	*         {@code equals} method; {@code false} otherwise
2523		* @throws NullPointerException if the specified key is null
2524		*/
917	–	@SuppressWarnings("unchecked")
2525		public boolean containsKey(Object key) {
2526	<	Segment<K,V> s; // same as get() except no need for volatile value read
920	<	HashEntry<K,V>[] tab;
921	<	int h = hash(key.hashCode());
922	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
923	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
924	<	(tab = s.table) != null) {
925	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
926	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
927	<	e != null; e = e.next) {
928	<	K k;
929	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
930	<	return true;
931	<	}
932	<	}
933	<	return false;
2526	>	return internalGet(key) != null;
2527		}
2528
2529		/**
2530	<	* Returns <tt>true</tt> if this map maps one or more keys to the
2531	<	* specified value. Note: This method requires a full internal
2532	<	* traversal of the hash table, and so is much slower than
940	<	* method <tt>containsKey</tt>.
2530	>	* Returns {@code true} if this map maps one or more keys to the
2531	>	* specified value. Note: This method may require a full traversal
2532	>	* of the map, and is much slower than method {@code containsKey}.
2533		*
2534		* @param value value whose presence in this map is to be tested
2535	<	* @return <tt>true</tt> if this map maps one or more keys to the
2535	>	* @return {@code true} if this map maps one or more keys to the
2536		*         specified value
2537		* @throws NullPointerException if the specified value is null
2538		*/
2539		public boolean containsValue(Object value) {
948	–	// Same idea as size()
2540		if (value == null)
2541		throw new NullPointerException();
2542	<	final Segment<K,V>[] segments = this.segments;
2543	<	boolean found = false;
2544	<	long last = 0L;   // previous sum
2545	<	int retries = -1;
2546	<	try {
956	<	outer: for (;;) {
957	<	if (retries++ == RETRIES_BEFORE_LOCK) {
958	<	for (int j = 0; j < segments.length; ++j)
959	<	ensureSegment(j).lock(); // force creation
960	<	}
961	<	long sum = 0L;
962	<	for (int j = 0; j < segments.length; ++j) {
963	<	HashEntry<K,V>[] tab;
964	<	Segment<K,V> seg = segmentAt(segments, j);
965	<	if (seg != null && (tab = seg.table) != null) {
966	<	for (int i = 0 ; i < tab.length; i++) {
967	<	HashEntry<K,V> e;
968	<	for (e = entryAt(tab, i); e != null; e = e.next) {
969	<	V v = e.value;
970	<	if (v != null && value.equals(v)) {
971	<	found = true;
972	<	break outer;
973	<	}
974	<	}
975	<	}
976	<	sum += seg.modCount;
977	<	}
978	<	}
979	<	if (retries > 0 && sum == last)
980	<	break;
981	<	last = sum;
982	<	}
983	<	} finally {
984	<	if (retries > RETRIES_BEFORE_LOCK) {
985	<	for (int j = 0; j < segments.length; ++j)
986	<	segmentAt(segments, j).unlock();
987	<	}
2542	>	V v;
2543	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2544	>	while ((v = it.advance()) != null) {
2545	>	if (v == value || value.equals(v))
2546	>	return true;
2547		}
2548	<	return found;
2548	>	return false;
2549		}
2550
2551		/**
2552		* Legacy method testing if some key maps into the specified value
2553		* in this table.  This method is identical in functionality to
2554	<	* {@link #containsValue}, and exists solely to ensure
2554	>	* {@link #containsValue(Object)}, and exists solely to ensure
2555		* full compatibility with class {@link java.util.Hashtable},
2556		* which supported this method prior to introduction of the
2557		* Java Collections framework.
2558		*
2559		* @param  value a value to search for
2560	<	* @return <tt>true</tt> if and only if some key maps to the
2561	<	*         <tt>value</tt> argument in this table as
2562	<	*         determined by the <tt>equals</tt> method;
2563	<	*         <tt>false</tt> otherwise
2560	>	* @return {@code true} if and only if some key maps to the
2561	>	*         {@code value} argument in this table as
2562	>	*         determined by the {@code equals} method;
2563	>	*         {@code false} otherwise
2564		* @throws NullPointerException if the specified value is null
2565		*/
2566	<	public boolean contains(Object value) {
2566	>	@Deprecated public boolean contains(Object value) {
2567		return containsValue(value);
2568		}
2569
#	Line 1012 | Line 2571 | public class ConcurrentHashMap<K, V> ext
2571		* Maps the specified key to the specified value in this table.
2572		* Neither the key nor the value can be null.
2573		*
2574	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
2574	>	* <p>The value can be retrieved by calling the {@code get} method
2575		* with a key that is equal to the original key.
2576		*
2577		* @param key key with which the specified value is to be associated
2578		* @param value value to be associated with the specified key
2579	<	* @return the previous value associated with <tt>key</tt>, or
2580	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2579	>	* @return the previous value associated with {@code key}, or
2580	>	*         {@code null} if there was no mapping for {@code key}
2581		* @throws NullPointerException if the specified key or value is null
2582		*/
1024	–	@SuppressWarnings("unchecked")
2583		public V put(K key, V value) {
2584	<	Segment<K,V> s;
1027	<	if (value == null)
1028	<	throw new NullPointerException();
1029	<	int hash = hash(key.hashCode());
1030	<	int j = (hash >>> segmentShift) & segmentMask;
1031	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1032	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1033	<	s = ensureSegment(j);
1034	<	return s.put(key, hash, value, false);
2584	>	return internalPut(key, value, false);
2585		}
2586
2587		/**
2588		* {@inheritDoc}
2589		*
2590		* @return the previous value associated with the specified key,
2591	<	*         or <tt>null</tt> if there was no mapping for the key
2591	>	*         or {@code null} if there was no mapping for the key
2592		* @throws NullPointerException if the specified key or value is null
2593		*/
1044	–	@SuppressWarnings("unchecked")
2594		public V putIfAbsent(K key, V value) {
2595	<	Segment<K,V> s;
1047	<	if (value == null)
1048	<	throw new NullPointerException();
1049	<	int hash = hash(key.hashCode());
1050	<	int j = (hash >>> segmentShift) & segmentMask;
1051	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1052	<	(segments, (j << SSHIFT) + SBASE)) == null)
1053	<	s = ensureSegment(j);
1054	<	return s.put(key, hash, value, true);
2595	>	return internalPut(key, value, true);
2596		}
2597
2598		/**
#	Line 1062 | Line 2603 | public class ConcurrentHashMap<K, V> ext
2603		* @param m mappings to be stored in this map
2604		*/
2605		public void putAll(Map<? extends K, ? extends V> m) {
2606	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2607	<	put(e.getKey(), e.getValue());
2606	>	internalPutAll(m);
2607	>	}
2608	>
2609	>	/**
2610	>	* If the specified key is not already associated with a value (or
2611	>	* is mapped to {@code null}), attempts to compute its value using
2612	>	* the given mapping function and enters it into this map unless
2613	>	* {@code null}. The entire method invocation is performed
2614	>	* atomically, so the function is applied at most once per key.
2615	>	* Some attempted update operations on this map by other threads
2616	>	* may be blocked while computation is in progress, so the
2617	>	* computation should be short and simple, and must not attempt to
2618	>	* update any other mappings of this Map.
2619	>	*
2620	>	* @param key key with which the specified value is to be associated
2621	>	* @param mappingFunction the function to compute a value
2622	>	* @return the current (existing or computed) value associated with
2623	>	*         the specified key, or null if the computed value is null
2624	>	* @throws NullPointerException if the specified key or mappingFunction
2625	>	*         is null
2626	>	* @throws IllegalStateException if the computation detectably
2627	>	*         attempts a recursive update to this map that would
2628	>	*         otherwise never complete
2629	>	* @throws RuntimeException or Error if the mappingFunction does so,
2630	>	*         in which case the mapping is left unestablished
2631	>	*/
2632	>	public V computeIfAbsent
2633	>	(K key, Function<? super K, ? extends V> mappingFunction) {
2634	>	return internalComputeIfAbsent(key, mappingFunction);
2635	>	}
2636	>
2637	>	/**
2638	>	* If the value for the specified key is present and non-null,
2639	>	* attempts to compute a new mapping given the key and its current
2640	>	* mapped value.  The entire method invocation is performed
2641	>	* atomically.  Some attempted update operations on this map by
2642	>	* other threads may be blocked while computation is in progress,
2643	>	* so the computation should be short and simple, and must not
2644	>	* attempt to update any other mappings of this Map.
2645	>	*
2646	>	* @param key key with which the specified value is to be associated
2647	>	* @param remappingFunction the function to compute a value
2648	>	* @return the new value associated with the specified key, or null if none
2649	>	* @throws NullPointerException if the specified key or remappingFunction
2650	>	*         is null
2651	>	* @throws IllegalStateException if the computation detectably
2652	>	*         attempts a recursive update to this map that would
2653	>	*         otherwise never complete
2654	>	* @throws RuntimeException or Error if the remappingFunction does so,
2655	>	*         in which case the mapping is unchanged
2656	>	*/
2657	>	public V computeIfPresent
2658	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2659	>	return internalCompute(key, true, remappingFunction);
2660	>	}
2661	>
2662	>	/**
2663	>	* Attempts to compute a mapping for the specified key and its
2664	>	* current mapped value (or {@code null} if there is no current
2665	>	* mapping). The entire method invocation is performed atomically.
2666	>	* Some attempted update operations on this map by other threads
2667	>	* may be blocked while computation is in progress, so the
2668	>	* computation should be short and simple, and must not attempt to
2669	>	* update any other mappings of this Map.
2670	>	*
2671	>	* @param key key with which the specified value is to be associated
2672	>	* @param remappingFunction the function to compute a value
2673	>	* @return the new value associated with the specified key, or null if none
2674	>	* @throws NullPointerException if the specified key or remappingFunction
2675	>	*         is null
2676	>	* @throws IllegalStateException if the computation detectably
2677	>	*         attempts a recursive update to this map that would
2678	>	*         otherwise never complete
2679	>	* @throws RuntimeException or Error if the remappingFunction does so,
2680	>	*         in which case the mapping is unchanged
2681	>	*/
2682	>	public V compute
2683	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2684	>	return internalCompute(key, false, remappingFunction);
2685	>	}
2686	>
2687	>	/**
2688	>	* If the specified key is not already associated with a
2689	>	* (non-null) value, associates it with the given value.
2690	>	* Otherwise, replaces the value with the results of the given
2691	>	* remapping function, or removes if {@code null}. The entire
2692	>	* method invocation is performed atomically.  Some attempted
2693	>	* update operations on this map by other threads may be blocked
2694	>	* while computation is in progress, so the computation should be
2695	>	* short and simple, and must not attempt to update any other
2696	>	* mappings of this Map.
2697	>	*
2698	>	* @param key key with which the specified value is to be associated
2699	>	* @param value the value to use if absent
2700	>	* @param remappingFunction the function to recompute a value if present
2701	>	* @return the new value associated with the specified key, or null if none
2702	>	* @throws NullPointerException if the specified key or the
2703	>	*         remappingFunction is null
2704	>	* @throws RuntimeException or Error if the remappingFunction does so,
2705	>	*         in which case the mapping is unchanged
2706	>	*/
2707	>	public V merge
2708	>	(K key, V value,
2709	>	BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2710	>	return internalMerge(key, value, remappingFunction);
2711		}
2712
2713		/**
#	Line 1071 | Line 2715 | public class ConcurrentHashMap<K, V> ext
2715		* This method does nothing if the key is not in the map.
2716		*
2717		* @param  key the key that needs to be removed
2718	<	* @return the previous value associated with <tt>key</tt>, or
2719	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2718	>	* @return the previous value associated with {@code key}, or
2719	>	*         {@code null} if there was no mapping for {@code key}
2720		* @throws NullPointerException if the specified key is null
2721		*/
2722		public V remove(Object key) {
2723	<	int hash = hash(key.hashCode());
1080	<	Segment<K,V> s = segmentForHash(hash);
1081	<	return s == null ? null : s.remove(key, hash, null);
2723	>	return internalReplace(key, null, null);
2724		}
2725
2726		/**
#	Line 1087 | Line 2729 | public class ConcurrentHashMap<K, V> ext
2729		* @throws NullPointerException if the specified key is null
2730		*/
2731		public boolean remove(Object key, Object value) {
2732	<	int hash = hash(key.hashCode());
2733	<	Segment<K,V> s;
2734	<	return value != null && (s = segmentForHash(hash)) != null &&
1093	<	s.remove(key, hash, value) != null;
2732	>	if (key == null)
2733	>	throw new NullPointerException();
2734	>	return value != null && internalReplace(key, null, value) != null;
2735		}
2736
2737		/**
#	Line 1099 | Line 2740 | public class ConcurrentHashMap<K, V> ext
2740		* @throws NullPointerException if any of the arguments are null
2741		*/
2742		public boolean replace(K key, V oldValue, V newValue) {
2743	<	int hash = hash(key.hashCode());
1103	<	if (oldValue == null || newValue == null)
2743	>	if (key == null || oldValue == null || newValue == null)
2744		throw new NullPointerException();
2745	<	Segment<K,V> s = segmentForHash(hash);
1106	<	return s != null && s.replace(key, hash, oldValue, newValue);
2745	>	return internalReplace(key, newValue, oldValue) != null;
2746		}
2747
2748		/**
2749		* {@inheritDoc}
2750		*
2751		* @return the previous value associated with the specified key,
2752	<	*         or <tt>null</tt> if there was no mapping for the key
2752	>	*         or {@code null} if there was no mapping for the key
2753		* @throws NullPointerException if the specified key or value is null
2754		*/
2755		public V replace(K key, V value) {
2756	<	int hash = hash(key.hashCode());
1118	<	if (value == null)
2756	>	if (key == null || value == null)
2757		throw new NullPointerException();
2758	<	Segment<K,V> s = segmentForHash(hash);
1121	<	return s == null ? null : s.replace(key, hash, value);
2758	>	return internalReplace(key, value, null);
2759		}
2760
2761		/**
2762		* Removes all of the mappings from this map.
2763		*/
2764		public void clear() {
2765	<	final Segment<K,V>[] segments = this.segments;
1129	<	for (int j = 0; j < segments.length; ++j) {
1130	<	Segment<K,V> s = segmentAt(segments, j);
1131	<	if (s != null)
1132	<	s.clear();
1133	<	}
2765	>	internalClear();
2766		}
2767
2768		/**
2769		* Returns a {@link Set} view of the keys contained in this map.
2770		* The set is backed by the map, so changes to the map are
2771	<	* reflected in the set, and vice-versa.  The set supports element
1140	<	* removal, which removes the corresponding mapping from this map,
1141	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1142	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1143	<	* operations.  It does not support the <tt>add</tt> or
1144	<	* <tt>addAll</tt> operations.
2771	>	* reflected in the set, and vice-versa.
2772		*
2773	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2774	<	* that will never throw {@link ConcurrentModificationException},
2775	<	* and guarantees to traverse elements as they existed upon
2776	<	* construction of the iterator, and may (but is not guaranteed to)
2777	<	* reflect any modifications subsequent to construction.
2773	>	* @return the set view
2774	>	*/
2775	>	public KeySetView<K,V> keySet() {
2776	>	KeySetView<K,V> ks = keySet;
2777	>	return (ks != null) ? ks : (keySet = new KeySetView<K,V>(this, null));
2778	>	}
2779	>
2780	>	/**
2781	>	* Returns a {@link Set} view of the keys in this map, using the
2782	>	* given common mapped value for any additions (i.e., {@link
2783	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2784	>	* This is of course only appropriate if it is acceptable to use
2785	>	* the same value for all additions from this view.
2786	>	*
2787	>	* @param mappedValue the mapped value to use for any additions
2788	>	* @return the set view
2789	>	* @throws NullPointerException if the mappedValue is null
2790		*/
2791	<	public Set<K> keySet() {
2792	<	Set<K> ks = keySet;
2793	<	return (ks != null) ? ks : (keySet = new KeySet());
2791	>	public KeySetView<K,V> keySet(V mappedValue) {
2792	>	if (mappedValue == null)
2793	>	throw new NullPointerException();
2794	>	return new KeySetView<K,V>(this, mappedValue);
2795		}
2796
2797		/**
2798		* Returns a {@link Collection} view of the values contained in this map.
2799		* The collection is backed by the map, so changes to the map are
2800	<	* reflected in the collection, and vice-versa.  The collection
1161	<	* supports element removal, which removes the corresponding
1162	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1163	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
1164	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
1165	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
2800	>	* reflected in the collection, and vice-versa.
2801		*
2802	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1168	<	* that will never throw {@link ConcurrentModificationException},
1169	<	* and guarantees to traverse elements as they existed upon
1170	<	* construction of the iterator, and may (but is not guaranteed to)
1171	<	* reflect any modifications subsequent to construction.
2802	>	* @return the collection view
2803		*/
2804	<	public Collection<V> values() {
2805	<	Collection<V> vs = values;
2806	<	return (vs != null) ? vs : (values = new Values());
2804	>	public ValuesView<K,V> values() {
2805	>	ValuesView<K,V> vs = values;
2806	>	return (vs != null) ? vs : (values = new ValuesView<K,V>(this));
2807		}
2808
2809		/**
#	Line 1180 | Line 2811 | public class ConcurrentHashMap<K, V> ext
2811		* The set is backed by the map, so changes to the map are
2812		* reflected in the set, and vice-versa.  The set supports element
2813		* removal, which removes the corresponding mapping from the map,
2814	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2815	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2816	<	* operations.  It does not support the <tt>add</tt> or
2817	<	* <tt>addAll</tt> operations.
2814	>	* via the {@code Iterator.remove}, {@code Set.remove},
2815	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2816	>	* operations.  It does not support the {@code add} or
2817	>	* {@code addAll} operations.
2818		*
2819	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2819	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2820		* that will never throw {@link ConcurrentModificationException},
2821		* and guarantees to traverse elements as they existed upon
2822		* construction of the iterator, and may (but is not guaranteed to)
2823		* reflect any modifications subsequent to construction.
2824	+	*
2825	+	* @return the set view
2826		*/
2827		public Set<Map.Entry<K,V>> entrySet() {
2828	<	Set<Map.Entry<K,V>> es = entrySet;
2829	<	return (es != null) ? es : (entrySet = new EntrySet());
2828	>	EntrySetView<K,V> es = entrySet;
2829	>	return (es != null) ? es : (entrySet = new EntrySetView<K,V>(this));
2830		}
2831
2832		/**
#	Line 1203 | Line 2836 | public class ConcurrentHashMap<K, V> ext
2836		* @see #keySet()
2837		*/
2838		public Enumeration<K> keys() {
2839	<	return new KeyIterator();
2839	>	return new KeyIterator<K,V>(this);
2840		}
2841
2842		/**
#	Line 1213 | Line 2846 | public class ConcurrentHashMap<K, V> ext
2846		* @see #values()
2847		*/
2848		public Enumeration<V> elements() {
2849	<	return new ValueIterator();
2849	>	return new ValueIterator<K,V>(this);
2850		}
2851
2852	<	/* ---------------- Iterator Support -------------- */
2853	<
2854	<	abstract class HashIterator {
2855	<	int nextSegmentIndex;
2856	<	int nextTableIndex;
2857	<	HashEntry<K,V>[] currentTable;
2858	<	HashEntry<K, V> nextEntry;
2859	<	HashEntry<K, V> lastReturned;
2860	<
2861	<	HashIterator() {
2862	<	nextSegmentIndex = segments.length - 1;
2863	<	nextTableIndex = -1;
2864	<	advance();
2865	<	}
2852	>	/**
2853	>	* Returns the hash code value for this {@link Map}, i.e.,
2854	>	* the sum of, for each key-value pair in the map,
2855	>	* {@code key.hashCode() ^ value.hashCode()}.
2856	>	*
2857	>	* @return the hash code value for this map
2858	>	*/
2859	>	public int hashCode() {
2860	>	int h = 0;
2861	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2862	>	V v;
2863	>	while ((v = it.advance()) != null) {
2864	>	h += it.nextKey.hashCode() ^ v.hashCode();
2865	>	}
2866	>	return h;
2867	>	}
2868
2869	<	/**
2870	<	* Sets nextEntry to first node of next non-empty table
2871	<	* (in backwards order, to simplify checks).
2872	<	*/
2873	<	final void advance() {
2869	>	/**
2870	>	* Returns a string representation of this map.  The string
2871	>	* representation consists of a list of key-value mappings (in no
2872	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
2873	>	* mappings are separated by the characters {@code ", "} (comma
2874	>	* and space).  Each key-value mapping is rendered as the key
2875	>	* followed by an equals sign ("{@code =}") followed by the
2876	>	* associated value.
2877	>	*
2878	>	* @return a string representation of this map
2879	>	*/
2880	>	public String toString() {
2881	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2882	>	StringBuilder sb = new StringBuilder();
2883	>	sb.append('{');
2884	>	V v;
2885	>	if ((v = it.advance()) != null) {
2886		for (;;) {
2887	<	if (nextTableIndex >= 0) {
2888	<	if ((nextEntry = entryAt(currentTable,
2889	<	nextTableIndex--)) != null)
2890	<	break;
2891	<	}
1245	<	else if (nextSegmentIndex >= 0) {
1246	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
1247	<	if (seg != null && (currentTable = seg.table) != null)
1248	<	nextTableIndex = currentTable.length - 1;
1249	<	}
1250	<	else
2887	>	K k = it.nextKey;
2888	>	sb.append(k == this ? "(this Map)" : k);
2889	>	sb.append('=');
2890	>	sb.append(v == this ? "(this Map)" : v);
2891	>	if ((v = it.advance()) == null)
2892		break;
2893	+	sb.append(',').append(' ');
2894		}
2895		}
2896	+	return sb.append('}').toString();
2897	+	}
2898
2899	<	final HashEntry<K,V> nextEntry() {
2900	<	HashEntry<K,V> e = nextEntry;
2901	<	if (e == null)
2899	>	/**
2900	>	* Compares the specified object with this map for equality.
2901	>	* Returns {@code true} if the given object is a map with the same
2902	>	* mappings as this map.  This operation may return misleading
2903	>	* results if either map is concurrently modified during execution
2904	>	* of this method.
2905	>	*
2906	>	* @param o object to be compared for equality with this map
2907	>	* @return {@code true} if the specified object is equal to this map
2908	>	*/
2909	>	public boolean equals(Object o) {
2910	>	if (o != this) {
2911	>	if (!(o instanceof Map))
2912	>	return false;
2913	>	Map<?,?> m = (Map<?,?>) o;
2914	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2915	>	V val;
2916	>	while ((val = it.advance()) != null) {
2917	>	Object v = m.get(it.nextKey);
2918	>	if (v == null || (v != val && !v.equals(val)))
2919	>	return false;
2920	>	}
2921	>	for (Map.Entry<?,?> e : m.entrySet()) {
2922	>	Object mk, mv, v;
2923	>	if ((mk = e.getKey()) == null ||
2924	>	(mv = e.getValue()) == null ||
2925	>	(v = internalGet(mk)) == null ||
2926	>	(mv != v && !mv.equals(v)))
2927	>	return false;
2928	>	}
2929	>	}
2930	>	return true;
2931	>	}
2932	>
2933	>	/* ----------------Iterators -------------- */
2934	>
2935	>	@SuppressWarnings("serial") static final class KeyIterator<K,V>
2936	>	extends Traverser<K,V,Object>
2937	>	implements Spliterator<K>, Iterator<K>, Enumeration<K> {
2938	>	KeyIterator(ConcurrentHashMap<K,V> map) { super(map); }
2939	>	KeyIterator(ConcurrentHashMap<K,V> map, Traverser<K,V,Object> it) {
2940	>	super(map, it);
2941	>	}
2942	>	public KeyIterator<K,V> trySplit() {
2943	>	if (tab != null && baseIndex == baseLimit)
2944	>	return null;
2945	>	return new KeyIterator<K,V>(map, this);
2946	>	}
2947	>	public final K next() {
2948	>	if (nextVal == null && advance() == null)
2949		throw new NoSuchElementException();
2950	<	lastReturned = e; // cannot assign until after null check
2951	<	if ((nextEntry = e.next) == null)
2952	<	advance();
1262	<	return e;
2950	>	K k = nextKey;
2951	>	nextVal = null;
2952	>	return k;
2953		}
2954
2955	<	public final boolean hasNext() { return nextEntry != null; }
1266	<	public final boolean hasMoreElements() { return nextEntry != null; }
2955	>	public final K nextElement() { return next(); }
2956
2957	<	public final void remove() {
2958	<	if (lastReturned == null)
2959	<	throw new IllegalStateException();
2960	<	ConcurrentHashMap.this.remove(lastReturned.key);
2961	<	lastReturned = null;
2957	>	public Iterator<K> iterator() { return this; }
2958	>
2959	>	public void forEach(Consumer<? super K> action) {
2960	>	if (action == null) throw new NullPointerException();
2961	>	while (advance() != null)
2962	>	action.accept(nextKey);
2963	>	}
2964	>
2965	>	public boolean tryAdvance(Consumer<? super K> block) {
2966	>	if (block == null) throw new NullPointerException();
2967	>	if (advance() == null)
2968	>	return false;
2969	>	block.accept(nextKey);
2970	>	return true;
2971		}
2972		}
2973
2974	<	final class KeyIterator
2975	<	extends HashIterator
2976	<	implements Iterator<K>, Enumeration<K>
2977	<	{
2978	<	public final K next()        { return super.nextEntry().key; }
2979	<	public final K nextElement() { return super.nextEntry().key; }
2974	>	@SuppressWarnings("serial") static final class ValueIterator<K,V>
2975	>	extends Traverser<K,V,Object>
2976	>	implements Spliterator<V>, Iterator<V>, Enumeration<V> {
2977	>	ValueIterator(ConcurrentHashMap<K,V> map) { super(map); }
2978	>	ValueIterator(ConcurrentHashMap<K,V> map, Traverser<K,V,Object> it) {
2979	>	super(map, it);
2980	>	}
2981	>	public ValueIterator<K,V> trySplit() {
2982	>	if (tab != null && baseIndex == baseLimit)
2983	>	return null;
2984	>	return new ValueIterator<K,V>(map, this);
2985	>	}
2986	>
2987	>	public final V next() {
2988	>	V v;
2989	>	if ((v = nextVal) == null && (v = advance()) == null)
2990	>	throw new NoSuchElementException();
2991	>	nextVal = null;
2992	>	return v;
2993	>	}
2994	>
2995	>	public final V nextElement() { return next(); }
2996	>
2997	>	public Iterator<V> iterator() { return this; }
2998	>
2999	>	public void forEach(Consumer<? super V> action) {
3000	>	if (action == null) throw new NullPointerException();
3001	>	V v;
3002	>	while ((v = advance()) != null)
3003	>	action.accept(v);
3004	>	}
3005	>
3006	>	public boolean tryAdvance(Consumer<? super V> block) {
3007	>	V v;
3008	>	if (block == null) throw new NullPointerException();
3009	>	if ((v = advance()) == null)
3010	>	return false;
3011	>	block.accept(v);
3012	>	return true;
3013	>	}
3014	>
3015		}
3016
3017	<	final class ValueIterator
3018	<	extends HashIterator
3019	<	implements Iterator<V>, Enumeration<V>
3020	<	{
3021	<	public final V next()        { return super.nextEntry().value; }
3022	<	public final V nextElement() { return super.nextEntry().value; }
3017	>	@SuppressWarnings("serial") static final class EntryIterator<K,V>
3018	>	extends Traverser<K,V,Object>
3019	>	implements Spliterator<Map.Entry<K,V>>, Iterator<Map.Entry<K,V>> {
3020	>	EntryIterator(ConcurrentHashMap<K,V> map) { super(map); }
3021	>	EntryIterator(ConcurrentHashMap<K,V> map, Traverser<K,V,Object> it) {
3022	>	super(map, it);
3023	>	}
3024	>	public EntryIterator<K,V> trySplit() {
3025	>	if (tab != null && baseIndex == baseLimit)
3026	>	return null;
3027	>	return new EntryIterator<K,V>(map, this);
3028	>	}
3029	>
3030	>	public final Map.Entry<K,V> next() {
3031	>	V v;
3032	>	if ((v = nextVal) == null && (v = advance()) == null)
3033	>	throw new NoSuchElementException();
3034	>	K k = nextKey;
3035	>	nextVal = null;
3036	>	return new MapEntry<K,V>(k, v, map);
3037	>	}
3038	>
3039	>	public Iterator<Map.Entry<K,V>> iterator() { return this; }
3040	>
3041	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
3042	>	if (action == null) throw new NullPointerException();
3043	>	V v;
3044	>	while ((v = advance()) != null)
3045	>	action.accept(entryFor(nextKey, v));
3046	>	}
3047	>
3048	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> block) {
3049	>	V v;
3050	>	if (block == null) throw new NullPointerException();
3051	>	if ((v = advance()) == null)
3052	>	return false;
3053	>	block.accept(entryFor(nextKey, v));
3054	>	return true;
3055	>	}
3056	>
3057		}
3058
3059		/**
3060	<	* Custom Entry class used by EntryIterator.next(), that relays
1294	<	* setValue changes to the underlying map.
3060	>	* Exported Entry for iterators
3061		*/
3062	<	final class WriteThroughEntry
3063	<	extends AbstractMap.SimpleEntry<K,V>
3064	<	{
3065	<	WriteThroughEntry(K k, V v) {
3066	<	super(k,v);
3062	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3063	>	final K key; // non-null
3064	>	V val;       // non-null
3065	>	final ConcurrentHashMap<K,V> map;
3066	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3067	>	this.key = key;
3068	>	this.val = val;
3069	>	this.map = map;
3070	>	}
3071	>	public final K getKey()       { return key; }
3072	>	public final V getValue()     { return val; }
3073	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3074	>	public final String toString(){ return key + "=" + val; }
3075	>
3076	>	public final boolean equals(Object o) {
3077	>	Object k, v; Map.Entry<?,?> e;
3078	>	return ((o instanceof Map.Entry) &&
3079	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3080	>	(v = e.getValue()) != null &&
3081	>	(k == key || k.equals(key)) &&
3082	>	(v == val || v.equals(val)));
3083		}
3084
3085		/**
3086		* Sets our entry's value and writes through to the map. The
3087	<	* value to return is somewhat arbitrary here. Since a
3088	<	* WriteThroughEntry does not necessarily track asynchronous
3089	<	* changes, the most recent "previous" value could be
3090	<	* different from what we return (or could even have been
3091	<	* removed in which case the put will re-establish). We do not
1310	<	* and cannot guarantee more.
3087	>	* value to return is somewhat arbitrary here. Since we do not
3088	>	* necessarily track asynchronous changes, the most recent
3089	>	* "previous" value could be different from what we return (or
3090	>	* could even have been removed in which case the put will
3091	>	* re-establish). We do not and cannot guarantee more.
3092		*/
3093	<	public V setValue(V value) {
3093	>	public final V setValue(V value) {
3094		if (value == null) throw new NullPointerException();
3095	<	V v = super.setValue(value);
3096	<	ConcurrentHashMap.this.put(getKey(), value);
3095	>	V v = val;
3096	>	val = value;
3097	>	map.put(key, value);
3098		return v;
3099		}
3100		}
3101
3102	<	final class EntryIterator
3103	<	extends HashIterator
3104	<	implements Iterator<Entry<K,V>>
3105	<	{
3106	<	public Map.Entry<K,V> next() {
3107	<	HashEntry<K,V> e = super.nextEntry();
3108	<	return new WriteThroughEntry(e.key, e.value);
3109	<	}
3102	>	/**
3103	>	* Returns exportable snapshot entry for the given key and value
3104	>	* when write-through can't or shouldn't be used.
3105	>	*/
3106	>	static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
3107	>	return new AbstractMap.SimpleEntry<K,V>(k, v);
3108	>	}
3109	>
3110	>	/* ---------------- Serialization Support -------------- */
3111	>
3112	>	/**
3113	>	* Stripped-down version of helper class used in previous version,
3114	>	* declared for the sake of serialization compatibility
3115	>	*/
3116	>	static class Segment<K,V> implements Serializable {
3117	>	private static final long serialVersionUID = 2249069246763182397L;
3118	>	final float loadFactor;
3119	>	Segment(float lf) { this.loadFactor = lf; }
3120		}
3121
3122	<	final class KeySet extends AbstractSet<K> {
3123	<	public Iterator<K> iterator() {
3124	<	return new KeyIterator();
3122	>	/**
3123	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
3124	>	* stream (i.e., serializes it).
3125	>	* @param s the stream
3126	>	* @serialData
3127	>	* the key (Object) and value (Object)
3128	>	* for each key-value mapping, followed by a null pair.
3129	>	* The key-value mappings are emitted in no particular order.
3130	>	*/
3131	>	@SuppressWarnings("unchecked") private void writeObject
3132	>	(java.io.ObjectOutputStream s)
3133	>	throws java.io.IOException {
3134	>	if (segments == null) { // for serialization compatibility
3135	>	segments = (Segment<K,V>[])
3136	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3137	>	for (int i = 0; i < segments.length; ++i)
3138	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3139		}
3140	<	public int size() {
3141	<	return ConcurrentHashMap.this.size();
3140	>	s.defaultWriteObject();
3141	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3142	>	V v;
3143	>	while ((v = it.advance()) != null) {
3144	>	s.writeObject(it.nextKey);
3145	>	s.writeObject(v);
3146		}
3147	<	public boolean isEmpty() {
3148	<	return ConcurrentHashMap.this.isEmpty();
3147	>	s.writeObject(null);
3148	>	s.writeObject(null);
3149	>	segments = null; // throw away
3150	>	}
3151	>
3152	>	/**
3153	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3154	>	* @param s the stream
3155	>	*/
3156	>	@SuppressWarnings("unchecked") private void readObject
3157	>	(java.io.ObjectInputStream s)
3158	>	throws java.io.IOException, ClassNotFoundException {
3159	>	s.defaultReadObject();
3160	>	this.segments = null; // unneeded
3161	>
3162	>	// Create all nodes, then place in table once size is known
3163	>	long size = 0L;
3164	>	Node<V> p = null;
3165	>	for (;;) {
3166	>	K k = (K) s.readObject();
3167	>	V v = (V) s.readObject();
3168	>	if (k != null && v != null) {
3169	>	int h = spread(k.hashCode());
3170	>	p = new Node<V>(h, k, v, p);
3171	>	++size;
3172	>	}
3173	>	else
3174	>	break;
3175		}
3176	<	public boolean contains(Object o) {
3177	<	return ConcurrentHashMap.this.containsKey(o);
3176	>	if (p != null) {
3177	>	boolean init = false;
3178	>	int n;
3179	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3180	>	n = MAXIMUM_CAPACITY;
3181	>	else {
3182	>	int sz = (int)size;
3183	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3184	>	}
3185	>	int sc = sizeCtl;
3186	>	boolean collide = false;
3187	>	if (n > sc &&
3188	>	U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
3189	>	try {
3190	>	if (table == null) {
3191	>	init = true;
3192	>	@SuppressWarnings("rawtypes") Node[] rt = new Node[n];
3193	>	Node<V>[] tab = (Node<V>[])rt;
3194	>	int mask = n - 1;
3195	>	while (p != null) {
3196	>	int j = p.hash & mask;
3197	>	Node<V> next = p.next;
3198	>	Node<V> q = p.next = tabAt(tab, j);
3199	>	setTabAt(tab, j, p);
3200	>	if (!collide && q != null && q.hash == p.hash)
3201	>	collide = true;
3202	>	p = next;
3203	>	}
3204	>	table = tab;
3205	>	addCount(size, -1);
3206	>	sc = n - (n >>> 2);
3207	>	}
3208	>	} finally {
3209	>	sizeCtl = sc;
3210	>	}
3211	>	if (collide) { // rescan and convert to TreeBins
3212	>	Node<V>[] tab = table;
3213	>	for (int i = 0; i < tab.length; ++i) {
3214	>	int c = 0;
3215	>	for (Node<V> e = tabAt(tab, i); e != null; e = e.next) {
3216	>	if (++c > TREE_THRESHOLD &&
3217	>	(e.key instanceof Comparable)) {
3218	>	replaceWithTreeBin(tab, i, e.key);
3219	>	break;
3220	>	}
3221	>	}
3222	>	}
3223	>	}
3224	>	}
3225	>	if (!init) { // Can only happen if unsafely published.
3226	>	while (p != null) {
3227	>	internalPut((K)p.key, p.val, false);
3228	>	p = p.next;
3229	>	}
3230	>	}
3231		}
3232	<	public boolean remove(Object o) {
3233	<	return ConcurrentHashMap.this.remove(o) != null;
3232	>	}
3233	>
3234	>	// -------------------------------------------------------
3235	>
3236	>	// Sequential bulk operations
3237	>
3238	>	/**
3239	>	* Performs the given action for each (key, value).
3240	>	*
3241	>	* @param action the action
3242	>	*/
3243	>	public void forEachSequentially
3244	>	(BiConsumer<? super K, ? super V> action) {
3245	>	if (action == null) throw new NullPointerException();
3246	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3247	>	V v;
3248	>	while ((v = it.advance()) != null)
3249	>	action.accept(it.nextKey, v);
3250	>	}
3251	>
3252	>	/**
3253	>	* Performs the given action for each non-null transformation
3254	>	* of each (key, value).
3255	>	*
3256	>	* @param transformer a function returning the transformation
3257	>	* for an element, or null if there is no transformation (in
3258	>	* which case the action is not applied)
3259	>	* @param action the action
3260	>	*/
3261	>	public <U> void forEachSequentially
3262	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3263	>	Consumer<? super U> action) {
3264	>	if (transformer == null || action == null)
3265	>	throw new NullPointerException();
3266	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3267	>	V v; U u;
3268	>	while ((v = it.advance()) != null) {
3269	>	if ((u = transformer.apply(it.nextKey, v)) != null)
3270	>	action.accept(u);
3271		}
3272	<	public void clear() {
3273	<	ConcurrentHashMap.this.clear();
3272	>	}
3273	>
3274	>	/**
3275	>	* Returns a non-null result from applying the given search
3276	>	* function on each (key, value), or null if none.
3277	>	*
3278	>	* @param searchFunction a function returning a non-null
3279	>	* result on success, else null
3280	>	* @return a non-null result from applying the given search
3281	>	* function on each (key, value), or null if none
3282	>	*/
3283	>	public <U> U searchSequentially
3284	>	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3285	>	if (searchFunction == null) throw new NullPointerException();
3286	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3287	>	V v; U u;
3288	>	while ((v = it.advance()) != null) {
3289	>	if ((u = searchFunction.apply(it.nextKey, v)) != null)
3290	>	return u;
3291		}
3292	+	return null;
3293		}
3294
3295	<	final class Values extends AbstractCollection<V> {
3296	<	public Iterator<V> iterator() {
3297	<	return new ValueIterator();
3295	>	/**
3296	>	* Returns the result of accumulating the given transformation
3297	>	* of all (key, value) pairs using the given reducer to
3298	>	* combine values, or null if none.
3299	>	*
3300	>	* @param transformer a function returning the transformation
3301	>	* for an element, or null if there is no transformation (in
3302	>	* which case it is not combined)
3303	>	* @param reducer a commutative associative combining function
3304	>	* @return the result of accumulating the given transformation
3305	>	* of all (key, value) pairs
3306	>	*/
3307	>	public <U> U reduceSequentially
3308	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3309	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3310	>	if (transformer == null || reducer == null)
3311	>	throw new NullPointerException();
3312	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3313	>	U r = null, u; V v;
3314	>	while ((v = it.advance()) != null) {
3315	>	if ((u = transformer.apply(it.nextKey, v)) != null)
3316	>	r = (r == null) ? u : reducer.apply(r, u);
3317		}
3318	<	public int size() {
3319	<	return ConcurrentHashMap.this.size();
3318	>	return r;
3319	>	}
3320	>
3321	>	/**
3322	>	* Returns the result of accumulating the given transformation
3323	>	* of all (key, value) pairs using the given reducer to
3324	>	* combine values, and the given basis as an identity value.
3325	>	*
3326	>	* @param transformer a function returning the transformation
3327	>	* for an element
3328	>	* @param basis the identity (initial default value) for the reduction
3329	>	* @param reducer a commutative associative combining function
3330	>	* @return the result of accumulating the given transformation
3331	>	* of all (key, value) pairs
3332	>	*/
3333	>	public double reduceToDoubleSequentially
3334	>	(ToDoubleBiFunction<? super K, ? super V> transformer,
3335	>	double basis,
3336	>	DoubleBinaryOperator reducer) {
3337	>	if (transformer == null || reducer == null)
3338	>	throw new NullPointerException();
3339	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3340	>	double r = basis; V v;
3341	>	while ((v = it.advance()) != null)
3342	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(it.nextKey, v));
3343	>	return r;
3344	>	}
3345	>
3346	>	/**
3347	>	* Returns the result of accumulating the given transformation
3348	>	* of all (key, value) pairs using the given reducer to
3349	>	* combine values, and the given basis as an identity value.
3350	>	*
3351	>	* @param transformer a function returning the transformation
3352	>	* for an element
3353	>	* @param basis the identity (initial default value) for the reduction
3354	>	* @param reducer a commutative associative combining function
3355	>	* @return the result of accumulating the given transformation
3356	>	* of all (key, value) pairs
3357	>	*/
3358	>	public long reduceToLongSequentially
3359	>	(ToLongBiFunction<? super K, ? super V> transformer,
3360	>	long basis,
3361	>	LongBinaryOperator reducer) {
3362	>	if (transformer == null || reducer == null)
3363	>	throw new NullPointerException();
3364	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3365	>	long r = basis; V v;
3366	>	while ((v = it.advance()) != null)
3367	>	r = reducer.applyAsLong(r, transformer.applyAsLong(it.nextKey, v));
3368	>	return r;
3369	>	}
3370	>
3371	>	/**
3372	>	* Returns the result of accumulating the given transformation
3373	>	* of all (key, value) pairs using the given reducer to
3374	>	* combine values, and the given basis as an identity value.
3375	>	*
3376	>	* @param transformer a function returning the transformation
3377	>	* for an element
3378	>	* @param basis the identity (initial default value) for the reduction
3379	>	* @param reducer a commutative associative combining function
3380	>	* @return the result of accumulating the given transformation
3381	>	* of all (key, value) pairs
3382	>	*/
3383	>	public int reduceToIntSequentially
3384	>	(ToIntBiFunction<? super K, ? super V> transformer,
3385	>	int basis,
3386	>	IntBinaryOperator reducer) {
3387	>	if (transformer == null || reducer == null)
3388	>	throw new NullPointerException();
3389	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3390	>	int r = basis; V v;
3391	>	while ((v = it.advance()) != null)
3392	>	r = reducer.applyAsInt(r, transformer.applyAsInt(it.nextKey, v));
3393	>	return r;
3394	>	}
3395	>
3396	>	/**
3397	>	* Performs the given action for each key.
3398	>	*
3399	>	* @param action the action
3400	>	*/
3401	>	public void forEachKeySequentially
3402	>	(Consumer<? super K> action) {
3403	>	if (action == null) throw new NullPointerException();
3404	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3405	>	while (it.advance() != null)
3406	>	action.accept(it.nextKey);
3407	>	}
3408	>
3409	>	/**
3410	>	* Performs the given action for each non-null transformation
3411	>	* of each key.
3412	>	*
3413	>	* @param transformer a function returning the transformation
3414	>	* for an element, or null if there is no transformation (in
3415	>	* which case the action is not applied)
3416	>	* @param action the action
3417	>	*/
3418	>	public <U> void forEachKeySequentially
3419	>	(Function<? super K, ? extends U> transformer,
3420	>	Consumer<? super U> action) {
3421	>	if (transformer == null || action == null)
3422	>	throw new NullPointerException();
3423	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3424	>	U u;
3425	>	while (it.advance() != null) {
3426	>	if ((u = transformer.apply(it.nextKey)) != null)
3427	>	action.accept(u);
3428		}
3429	<	public boolean isEmpty() {
3430	<	return ConcurrentHashMap.this.isEmpty();
3429	>	ForkJoinTasks.forEachKey
3430	>	(this, transformer, action).invoke();
3431	>	}
3432	>
3433	>	/**
3434	>	* Returns a non-null result from applying the given search
3435	>	* function on each key, or null if none.
3436	>	*
3437	>	* @param searchFunction a function returning a non-null
3438	>	* result on success, else null
3439	>	* @return a non-null result from applying the given search
3440	>	* function on each key, or null if none
3441	>	*/
3442	>	public <U> U searchKeysSequentially
3443	>	(Function<? super K, ? extends U> searchFunction) {
3444	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3445	>	U u;
3446	>	while (it.advance() != null) {
3447	>	if ((u = searchFunction.apply(it.nextKey)) != null)
3448	>	return u;
3449		}
3450	<	public boolean contains(Object o) {
3451	<	return ConcurrentHashMap.this.containsValue(o);
3450	>	return null;
3451	>	}
3452	>
3453	>	/**
3454	>	* Returns the result of accumulating all keys using the given
3455	>	* reducer to combine values, or null if none.
3456	>	*
3457	>	* @param reducer a commutative associative combining function
3458	>	* @return the result of accumulating all keys using the given
3459	>	* reducer to combine values, or null if none
3460	>	*/
3461	>	public K reduceKeysSequentially
3462	>	(BiFunction<? super K, ? super K, ? extends K> reducer) {
3463	>	if (reducer == null) throw new NullPointerException();
3464	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3465	>	K r = null;
3466	>	while (it.advance() != null) {
3467	>	K u = it.nextKey;
3468	>	r = (r == null) ? u : reducer.apply(r, u);
3469	>	}
3470	>	return r;
3471	>	}
3472	>
3473	>	/**
3474	>	* Returns the result of accumulating the given transformation
3475	>	* of all keys using the given reducer to combine values, or
3476	>	* null if none.
3477	>	*
3478	>	* @param transformer a function returning the transformation
3479	>	* for an element, or null if there is no transformation (in
3480	>	* which case it is not combined)
3481	>	* @param reducer a commutative associative combining function
3482	>	* @return the result of accumulating the given transformation
3483	>	* of all keys
3484	>	*/
3485	>	public <U> U reduceKeysSequentially
3486	>	(Function<? super K, ? extends U> transformer,
3487	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3488	>	if (transformer == null || reducer == null)
3489	>	throw new NullPointerException();
3490	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3491	>	U r = null, u;
3492	>	while (it.advance() != null) {
3493	>	if ((u = transformer.apply(it.nextKey)) != null)
3494	>	r = (r == null) ? u : reducer.apply(r, u);
3495		}
3496	<	public void clear() {
3497	<	ConcurrentHashMap.this.clear();
3496	>	return r;
3497	>	}
3498	>
3499	>	/**
3500	>	* Returns the result of accumulating the given transformation
3501	>	* of all keys using the given reducer to combine values, and
3502	>	* the given basis as an identity value.
3503	>	*
3504	>	* @param transformer a function returning the transformation
3505	>	* for an element
3506	>	* @param basis the identity (initial default value) for the reduction
3507	>	* @param reducer a commutative associative combining function
3508	>	* @return the result of accumulating the given transformation
3509	>	* of all keys
3510	>	*/
3511	>	public double reduceKeysToDoubleSequentially
3512	>	(ToDoubleFunction<? super K> transformer,
3513	>	double basis,
3514	>	DoubleBinaryOperator reducer) {
3515	>	if (transformer == null || reducer == null)
3516	>	throw new NullPointerException();
3517	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3518	>	double r = basis;
3519	>	while (it.advance() != null)
3520	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(it.nextKey));
3521	>	return r;
3522	>	}
3523	>
3524	>	/**
3525	>	* Returns the result of accumulating the given transformation
3526	>	* of all keys using the given reducer to combine values, and
3527	>	* the given basis as an identity value.
3528	>	*
3529	>	* @param transformer a function returning the transformation
3530	>	* for an element
3531	>	* @param basis the identity (initial default value) for the reduction
3532	>	* @param reducer a commutative associative combining function
3533	>	* @return the result of accumulating the given transformation
3534	>	* of all keys
3535	>	*/
3536	>	public long reduceKeysToLongSequentially
3537	>	(ToLongFunction<? super K> transformer,
3538	>	long basis,
3539	>	LongBinaryOperator reducer) {
3540	>	if (transformer == null || reducer == null)
3541	>	throw new NullPointerException();
3542	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3543	>	long r = basis;
3544	>	while (it.advance() != null)
3545	>	r = reducer.applyAsLong(r, transformer.applyAsLong(it.nextKey));
3546	>	return r;
3547	>	}
3548	>
3549	>	/**
3550	>	* Returns the result of accumulating the given transformation
3551	>	* of all keys using the given reducer to combine values, and
3552	>	* the given basis as an identity value.
3553	>	*
3554	>	* @param transformer a function returning the transformation
3555	>	* for an element
3556	>	* @param basis the identity (initial default value) for the reduction
3557	>	* @param reducer a commutative associative combining function
3558	>	* @return the result of accumulating the given transformation
3559	>	* of all keys
3560	>	*/
3561	>	public int reduceKeysToIntSequentially
3562	>	(ToIntFunction<? super K> transformer,
3563	>	int basis,
3564	>	IntBinaryOperator reducer) {
3565	>	if (transformer == null || reducer == null)
3566	>	throw new NullPointerException();
3567	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3568	>	int r = basis;
3569	>	while (it.advance() != null)
3570	>	r = reducer.applyAsInt(r, transformer.applyAsInt(it.nextKey));
3571	>	return r;
3572	>	}
3573	>
3574	>	/**
3575	>	* Performs the given action for each value.
3576	>	*
3577	>	* @param action the action
3578	>	*/
3579	>	public void forEachValueSequentially(Consumer<? super V> action) {
3580	>	if (action == null) throw new NullPointerException();
3581	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3582	>	V v;
3583	>	while ((v = it.advance()) != null)
3584	>	action.accept(v);
3585	>	}
3586	>
3587	>	/**
3588	>	* Performs the given action for each non-null transformation
3589	>	* of each value.
3590	>	*
3591	>	* @param transformer a function returning the transformation
3592	>	* for an element, or null if there is no transformation (in
3593	>	* which case the action is not applied)
3594	>	* @param action the action
3595	>	*/
3596	>	public <U> void forEachValueSequentially
3597	>	(Function<? super V, ? extends U> transformer,
3598	>	Consumer<? super U> action) {
3599	>	if (transformer == null || action == null)
3600	>	throw new NullPointerException();
3601	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3602	>	V v; U u;
3603	>	while ((v = it.advance()) != null) {
3604	>	if ((u = transformer.apply(v)) != null)
3605	>	action.accept(u);
3606		}
3607		}
3608
3609	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3610	<	public Iterator<Map.Entry<K,V>> iterator() {
3611	<	return new EntryIterator();
3609	>	/**
3610	>	* Returns a non-null result from applying the given search
3611	>	* function on each value, or null if none.
3612	>	*
3613	>	* @param searchFunction a function returning a non-null
3614	>	* result on success, else null
3615	>	* @return a non-null result from applying the given search
3616	>	* function on each value, or null if none
3617	>	*/
3618	>	public <U> U searchValuesSequentially
3619	>	(Function<? super V, ? extends U> searchFunction) {
3620	>	if (searchFunction == null) throw new NullPointerException();
3621	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3622	>	V v; U u;
3623	>	while ((v = it.advance()) != null) {
3624	>	if ((u = searchFunction.apply(v)) != null)
3625	>	return u;
3626		}
3627	<	public boolean contains(Object o) {
3628	<	if (!(o instanceof Map.Entry))
3629	<	return false;
3630	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3631	<	V v = ConcurrentHashMap.this.get(e.getKey());
3632	<	return v != null && v.equals(e.getValue());
3627	>	return null;
3628	>	}
3629	>
3630	>	/**
3631	>	* Returns the result of accumulating all values using the
3632	>	* given reducer to combine values, or null if none.
3633	>	*
3634	>	* @param reducer a commutative associative combining function
3635	>	* @return the result of accumulating all values
3636	>	*/
3637	>	public V reduceValuesSequentially
3638	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
3639	>	if (reducer == null) throw new NullPointerException();
3640	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3641	>	V r = null; V v;
3642	>	while ((v = it.advance()) != null)
3643	>	r = (r == null) ? v : reducer.apply(r, v);
3644	>	return r;
3645	>	}
3646	>
3647	>	/**
3648	>	* Returns the result of accumulating the given transformation
3649	>	* of all values using the given reducer to combine values, or
3650	>	* null if none.
3651	>	*
3652	>	* @param transformer a function returning the transformation
3653	>	* for an element, or null if there is no transformation (in
3654	>	* which case it is not combined)
3655	>	* @param reducer a commutative associative combining function
3656	>	* @return the result of accumulating the given transformation
3657	>	* of all values
3658	>	*/
3659	>	public <U> U reduceValuesSequentially
3660	>	(Function<? super V, ? extends U> transformer,
3661	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3662	>	if (transformer == null || reducer == null)
3663	>	throw new NullPointerException();
3664	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3665	>	U r = null, u; V v;
3666	>	while ((v = it.advance()) != null) {
3667	>	if ((u = transformer.apply(v)) != null)
3668	>	r = (r == null) ? u : reducer.apply(r, u);
3669		}
3670	<	public boolean remove(Object o) {
3671	<	if (!(o instanceof Map.Entry))
3672	<	return false;
3673	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3674	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
3670	>	return r;
3671	>	}
3672	>
3673	>	/**
3674	>	* Returns the result of accumulating the given transformation
3675	>	* of all values using the given reducer to combine values,
3676	>	* and the given basis as an identity value.
3677	>	*
3678	>	* @param transformer a function returning the transformation
3679	>	* for an element
3680	>	* @param basis the identity (initial default value) for the reduction
3681	>	* @param reducer a commutative associative combining function
3682	>	* @return the result of accumulating the given transformation
3683	>	* of all values
3684	>	*/
3685	>	public double reduceValuesToDoubleSequentially
3686	>	(ToDoubleFunction<? super V> transformer,
3687	>	double basis,
3688	>	DoubleBinaryOperator reducer) {
3689	>	if (transformer == null || reducer == null)
3690	>	throw new NullPointerException();
3691	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3692	>	double r = basis; V v;
3693	>	while ((v = it.advance()) != null)
3694	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
3695	>	return r;
3696	>	}
3697	>
3698	>	/**
3699	>	* Returns the result of accumulating the given transformation
3700	>	* of all values using the given reducer to combine values,
3701	>	* and the given basis as an identity value.
3702	>	*
3703	>	* @param transformer a function returning the transformation
3704	>	* for an element
3705	>	* @param basis the identity (initial default value) for the reduction
3706	>	* @param reducer a commutative associative combining function
3707	>	* @return the result of accumulating the given transformation
3708	>	* of all values
3709	>	*/
3710	>	public long reduceValuesToLongSequentially
3711	>	(ToLongFunction<? super V> transformer,
3712	>	long basis,
3713	>	LongBinaryOperator reducer) {
3714	>	if (transformer == null || reducer == null)
3715	>	throw new NullPointerException();
3716	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3717	>	long r = basis; V v;
3718	>	while ((v = it.advance()) != null)
3719	>	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
3720	>	return r;
3721	>	}
3722	>
3723	>	/**
3724	>	* Returns the result of accumulating the given transformation
3725	>	* of all values using the given reducer to combine values,
3726	>	* and the given basis as an identity value.
3727	>	*
3728	>	* @param transformer a function returning the transformation
3729	>	* for an element
3730	>	* @param basis the identity (initial default value) for the reduction
3731	>	* @param reducer a commutative associative combining function
3732	>	* @return the result of accumulating the given transformation
3733	>	* of all values
3734	>	*/
3735	>	public int reduceValuesToIntSequentially
3736	>	(ToIntFunction<? super V> transformer,
3737	>	int basis,
3738	>	IntBinaryOperator reducer) {
3739	>	if (transformer == null || reducer == null)
3740	>	throw new NullPointerException();
3741	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3742	>	int r = basis; V v;
3743	>	while ((v = it.advance()) != null)
3744	>	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
3745	>	return r;
3746	>	}
3747	>
3748	>	/**
3749	>	* Performs the given action for each entry.
3750	>	*
3751	>	* @param action the action
3752	>	*/
3753	>	public void forEachEntrySequentially
3754	>	(Consumer<? super Map.Entry<K,V>> action) {
3755	>	if (action == null) throw new NullPointerException();
3756	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3757	>	V v;
3758	>	while ((v = it.advance()) != null)
3759	>	action.accept(entryFor(it.nextKey, v));
3760	>	}
3761	>
3762	>	/**
3763	>	* Performs the given action for each non-null transformation
3764	>	* of each entry.
3765	>	*
3766	>	* @param transformer a function returning the transformation
3767	>	* for an element, or null if there is no transformation (in
3768	>	* which case the action is not applied)
3769	>	* @param action the action
3770	>	*/
3771	>	public <U> void forEachEntrySequentially
3772	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3773	>	Consumer<? super U> action) {
3774	>	if (transformer == null || action == null)
3775	>	throw new NullPointerException();
3776	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3777	>	V v; U u;
3778	>	while ((v = it.advance()) != null) {
3779	>	if ((u = transformer.apply(entryFor(it.nextKey, v))) != null)
3780	>	action.accept(u);
3781		}
3782	<	public int size() {
3783	<	return ConcurrentHashMap.this.size();
3782	>	}
3783	>
3784	>	/**
3785	>	* Returns a non-null result from applying the given search
3786	>	* function on each entry, or null if none.
3787	>	*
3788	>	* @param searchFunction a function returning a non-null
3789	>	* result on success, else null
3790	>	* @return a non-null result from applying the given search
3791	>	* function on each entry, or null if none
3792	>	*/
3793	>	public <U> U searchEntriesSequentially
3794	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
3795	>	if (searchFunction == null) throw new NullPointerException();
3796	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3797	>	V v; U u;
3798	>	while ((v = it.advance()) != null) {
3799	>	if ((u = searchFunction.apply(entryFor(it.nextKey, v))) != null)
3800	>	return u;
3801		}
3802	<	public boolean isEmpty() {
3803	<	return ConcurrentHashMap.this.isEmpty();
3802	>	return null;
3803	>	}
3804	>
3805	>	/**
3806	>	* Returns the result of accumulating all entries using the
3807	>	* given reducer to combine values, or null if none.
3808	>	*
3809	>	* @param reducer a commutative associative combining function
3810	>	* @return the result of accumulating all entries
3811	>	*/
3812	>	public Map.Entry<K,V> reduceEntriesSequentially
3813	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3814	>	if (reducer == null) throw new NullPointerException();
3815	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3816	>	Map.Entry<K,V> r = null; V v;
3817	>	while ((v = it.advance()) != null) {
3818	>	Map.Entry<K,V> u = entryFor(it.nextKey, v);
3819	>	r = (r == null) ? u : reducer.apply(r, u);
3820		}
3821	<	public void clear() {
3822	<	ConcurrentHashMap.this.clear();
3821	>	return r;
3822	>	}
3823	>
3824	>	/**
3825	>	* Returns the result of accumulating the given transformation
3826	>	* of all entries using the given reducer to combine values,
3827	>	* or null if none.
3828	>	*
3829	>	* @param transformer a function returning the transformation
3830	>	* for an element, or null if there is no transformation (in
3831	>	* which case it is not combined)
3832	>	* @param reducer a commutative associative combining function
3833	>	* @return the result of accumulating the given transformation
3834	>	* of all entries
3835	>	*/
3836	>	public <U> U reduceEntriesSequentially
3837	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3838	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3839	>	if (transformer == null || reducer == null)
3840	>	throw new NullPointerException();
3841	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3842	>	U r = null, u; V v;
3843	>	while ((v = it.advance()) != null) {
3844	>	if ((u = transformer.apply(entryFor(it.nextKey, v))) != null)
3845	>	r = (r == null) ? u : reducer.apply(r, u);
3846		}
3847	+	return r;
3848		}
3849
3850	<	/* ---------------- Serialization Support -------------- */
3850	>	/**
3851	>	* Returns the result of accumulating the given transformation
3852	>	* of all entries using the given reducer to combine values,
3853	>	* and the given basis as an identity value.
3854	>	*
3855	>	* @param transformer a function returning the transformation
3856	>	* for an element
3857	>	* @param basis the identity (initial default value) for the reduction
3858	>	* @param reducer a commutative associative combining function
3859	>	* @return the result of accumulating the given transformation
3860	>	* of all entries
3861	>	*/
3862	>	public double reduceEntriesToDoubleSequentially
3863	>	(ToDoubleFunction<Map.Entry<K,V>> transformer,
3864	>	double basis,
3865	>	DoubleBinaryOperator reducer) {
3866	>	if (transformer == null || reducer == null)
3867	>	throw new NullPointerException();
3868	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3869	>	double r = basis; V v;
3870	>	while ((v = it.advance()) != null)
3871	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor(it.nextKey, v)));
3872	>	return r;
3873	>	}
3874
3875		/**
3876	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
3877	<	* stream (i.e., serializes it).
3878	<	* @param s the stream
3879	<	* @serialData
3880	<	* the key (Object) and value (Object)
3881	<	* for each key-value mapping, followed by a null pair.
3882	<	* The key-value mappings are emitted in no particular order.
3876	>	* Returns the result of accumulating the given transformation
3877	>	* of all entries using the given reducer to combine values,
3878	>	* and the given basis as an identity value.
3879	>	*
3880	>	* @param transformer a function returning the transformation
3881	>	* for an element
3882	>	* @param basis the identity (initial default value) for the reduction
3883	>	* @param reducer a commutative associative combining function
3884	>	* @return the result of accumulating the given transformation
3885	>	* of all entries
3886	>	*/
3887	>	public long reduceEntriesToLongSequentially
3888	>	(ToLongFunction<Map.Entry<K,V>> transformer,
3889	>	long basis,
3890	>	LongBinaryOperator reducer) {
3891	>	if (transformer == null || reducer == null)
3892	>	throw new NullPointerException();
3893	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3894	>	long r = basis; V v;
3895	>	while ((v = it.advance()) != null)
3896	>	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor(it.nextKey, v)));
3897	>	return r;
3898	>	}
3899	>
3900	>	/**
3901	>	* Returns the result of accumulating the given transformation
3902	>	* of all entries using the given reducer to combine values,
3903	>	* and the given basis as an identity value.
3904	>	*
3905	>	* @param transformer a function returning the transformation
3906	>	* for an element
3907	>	* @param basis the identity (initial default value) for the reduction
3908	>	* @param reducer a commutative associative combining function
3909	>	* @return the result of accumulating the given transformation
3910	>	* of all entries
3911	>	*/
3912	>	public int reduceEntriesToIntSequentially
3913	>	(ToIntFunction<Map.Entry<K,V>> transformer,
3914	>	int basis,
3915	>	IntBinaryOperator reducer) {
3916	>	if (transformer == null || reducer == null)
3917	>	throw new NullPointerException();
3918	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3919	>	int r = basis; V v;
3920	>	while ((v = it.advance()) != null)
3921	>	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor(it.nextKey, v)));
3922	>	return r;
3923	>	}
3924	>
3925	>	// Parallel bulk operations
3926	>
3927	>	/**
3928	>	* Performs the given action for each (key, value).
3929	>	*
3930	>	* @param action the action
3931		*/
3932	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException {
3933	<	// force all segments for serialization compatibility
3934	<	for (int k = 0; k < segments.length; ++k)
3935	<	ensureSegment(k);
1412	<	s.defaultWriteObject();
3932	>	public void forEachInParallel(BiConsumer<? super K,? super V> action) {
3933	>	ForkJoinTasks.forEach
3934	>	(this, action).invoke();
3935	>	}
3936
3937	<	final Segment<K,V>[] segments = this.segments;
3938	<	for (int k = 0; k < segments.length; ++k) {
3939	<	Segment<K,V> seg = segmentAt(segments, k);
3940	<	seg.lock();
3941	<	try {
3942	<	HashEntry<K,V>[] tab = seg.table;
3943	<	for (int i = 0; i < tab.length; ++i) {
3944	<	HashEntry<K,V> e;
3945	<	for (e = entryAt(tab, i); e != null; e = e.next) {
3946	<	s.writeObject(e.key);
3947	<	s.writeObject(e.value);
3937	>	/**
3938	>	* Performs the given action for each non-null transformation
3939	>	* of each (key, value).
3940	>	*
3941	>	* @param transformer a function returning the transformation
3942	>	* for an element, or null if there is no transformation (in
3943	>	* which case the action is not applied)
3944	>	* @param action the action
3945	>	*/
3946	>	public <U> void forEachInParallel
3947	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3948	>	Consumer<? super U> action) {
3949	>	ForkJoinTasks.forEach
3950	>	(this, transformer, action).invoke();
3951	>	}
3952	>
3953	>	/**
3954	>	* Returns a non-null result from applying the given search
3955	>	* function on each (key, value), or null if none.  Upon
3956	>	* success, further element processing is suppressed and the
3957	>	* results of any other parallel invocations of the search
3958	>	* function are ignored.
3959	>	*
3960	>	* @param searchFunction a function returning a non-null
3961	>	* result on success, else null
3962	>	* @return a non-null result from applying the given search
3963	>	* function on each (key, value), or null if none
3964	>	*/
3965	>	public <U> U searchInParallel
3966	>	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3967	>	return ForkJoinTasks.search
3968	>	(this, searchFunction).invoke();
3969	>	}
3970	>
3971	>	/**
3972	>	* Returns the result of accumulating the given transformation
3973	>	* of all (key, value) pairs using the given reducer to
3974	>	* combine values, or null if none.
3975	>	*
3976	>	* @param transformer a function returning the transformation
3977	>	* for an element, or null if there is no transformation (in
3978	>	* which case it is not combined)
3979	>	* @param reducer a commutative associative combining function
3980	>	* @return the result of accumulating the given transformation
3981	>	* of all (key, value) pairs
3982	>	*/
3983	>	public <U> U reduceInParallel
3984	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3985	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3986	>	return ForkJoinTasks.reduce
3987	>	(this, transformer, reducer).invoke();
3988	>	}
3989	>
3990	>	/**
3991	>	* Returns the result of accumulating the given transformation
3992	>	* of all (key, value) pairs using the given reducer to
3993	>	* combine values, and the given basis as an identity value.
3994	>	*
3995	>	* @param transformer a function returning the transformation
3996	>	* for an element
3997	>	* @param basis the identity (initial default value) for the reduction
3998	>	* @param reducer a commutative associative combining function
3999	>	* @return the result of accumulating the given transformation
4000	>	* of all (key, value) pairs
4001	>	*/
4002	>	public double reduceToDoubleInParallel
4003	>	(ToDoubleBiFunction<? super K, ? super V> transformer,
4004	>	double basis,
4005	>	DoubleBinaryOperator reducer) {
4006	>	return ForkJoinTasks.reduceToDouble
4007	>	(this, transformer, basis, reducer).invoke();
4008	>	}
4009	>
4010	>	/**
4011	>	* Returns the result of accumulating the given transformation
4012	>	* of all (key, value) pairs using the given reducer to
4013	>	* combine values, and the given basis as an identity value.
4014	>	*
4015	>	* @param transformer a function returning the transformation
4016	>	* for an element
4017	>	* @param basis the identity (initial default value) for the reduction
4018	>	* @param reducer a commutative associative combining function
4019	>	* @return the result of accumulating the given transformation
4020	>	* of all (key, value) pairs
4021	>	*/
4022	>	public long reduceToLongInParallel
4023	>	(ToLongBiFunction<? super K, ? super V> transformer,
4024	>	long basis,
4025	>	LongBinaryOperator reducer) {
4026	>	return ForkJoinTasks.reduceToLong
4027	>	(this, transformer, basis, reducer).invoke();
4028	>	}
4029	>
4030	>	/**
4031	>	* Returns the result of accumulating the given transformation
4032	>	* of all (key, value) pairs using the given reducer to
4033	>	* combine values, and the given basis as an identity value.
4034	>	*
4035	>	* @param transformer a function returning the transformation
4036	>	* for an element
4037	>	* @param basis the identity (initial default value) for the reduction
4038	>	* @param reducer a commutative associative combining function
4039	>	* @return the result of accumulating the given transformation
4040	>	* of all (key, value) pairs
4041	>	*/
4042	>	public int reduceToIntInParallel
4043	>	(ToIntBiFunction<? super K, ? super V> transformer,
4044	>	int basis,
4045	>	IntBinaryOperator reducer) {
4046	>	return ForkJoinTasks.reduceToInt
4047	>	(this, transformer, basis, reducer).invoke();
4048	>	}
4049	>
4050	>	/**
4051	>	* Performs the given action for each key.
4052	>	*
4053	>	* @param action the action
4054	>	*/
4055	>	public void forEachKeyInParallel(Consumer<? super K> action) {
4056	>	ForkJoinTasks.forEachKey
4057	>	(this, action).invoke();
4058	>	}
4059	>
4060	>	/**
4061	>	* Performs the given action for each non-null transformation
4062	>	* of each key.
4063	>	*
4064	>	* @param transformer a function returning the transformation
4065	>	* for an element, or null if there is no transformation (in
4066	>	* which case the action is not applied)
4067	>	* @param action the action
4068	>	*/
4069	>	public <U> void forEachKeyInParallel
4070	>	(Function<? super K, ? extends U> transformer,
4071	>	Consumer<? super U> action) {
4072	>	ForkJoinTasks.forEachKey
4073	>	(this, transformer, action).invoke();
4074	>	}
4075	>
4076	>	/**
4077	>	* Returns a non-null result from applying the given search
4078	>	* function on each key, or null if none. Upon success,
4079	>	* further element processing is suppressed and the results of
4080	>	* any other parallel invocations of the search function are
4081	>	* ignored.
4082	>	*
4083	>	* @param searchFunction a function returning a non-null
4084	>	* result on success, else null
4085	>	* @return a non-null result from applying the given search
4086	>	* function on each key, or null if none
4087	>	*/
4088	>	public <U> U searchKeysInParallel
4089	>	(Function<? super K, ? extends U> searchFunction) {
4090	>	return ForkJoinTasks.searchKeys
4091	>	(this, searchFunction).invoke();
4092	>	}
4093	>
4094	>	/**
4095	>	* Returns the result of accumulating all keys using the given
4096	>	* reducer to combine values, or null if none.
4097	>	*
4098	>	* @param reducer a commutative associative combining function
4099	>	* @return the result of accumulating all keys using the given
4100	>	* reducer to combine values, or null if none
4101	>	*/
4102	>	public K reduceKeysInParallel
4103	>	(BiFunction<? super K, ? super K, ? extends K> reducer) {
4104	>	return ForkJoinTasks.reduceKeys
4105	>	(this, reducer).invoke();
4106	>	}
4107	>
4108	>	/**
4109	>	* Returns the result of accumulating the given transformation
4110	>	* of all keys using the given reducer to combine values, or
4111	>	* null if none.
4112	>	*
4113	>	* @param transformer a function returning the transformation
4114	>	* for an element, or null if there is no transformation (in
4115	>	* which case it is not combined)
4116	>	* @param reducer a commutative associative combining function
4117	>	* @return the result of accumulating the given transformation
4118	>	* of all keys
4119	>	*/
4120	>	public <U> U reduceKeysInParallel
4121	>	(Function<? super K, ? extends U> transformer,
4122	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4123	>	return ForkJoinTasks.reduceKeys
4124	>	(this, transformer, reducer).invoke();
4125	>	}
4126	>
4127	>	/**
4128	>	* Returns the result of accumulating the given transformation
4129	>	* of all keys using the given reducer to combine values, and
4130	>	* the given basis as an identity value.
4131	>	*
4132	>	* @param transformer a function returning the transformation
4133	>	* for an element
4134	>	* @param basis the identity (initial default value) for the reduction
4135	>	* @param reducer a commutative associative combining function
4136	>	* @return the result of accumulating the given transformation
4137	>	* of all keys
4138	>	*/
4139	>	public double reduceKeysToDoubleInParallel
4140	>	(ToDoubleFunction<? super K> transformer,
4141	>	double basis,
4142	>	DoubleBinaryOperator reducer) {
4143	>	return ForkJoinTasks.reduceKeysToDouble
4144	>	(this, transformer, basis, reducer).invoke();
4145	>	}
4146	>
4147	>	/**
4148	>	* Returns the result of accumulating the given transformation
4149	>	* of all keys using the given reducer to combine values, and
4150	>	* the given basis as an identity value.
4151	>	*
4152	>	* @param transformer a function returning the transformation
4153	>	* for an element
4154	>	* @param basis the identity (initial default value) for the reduction
4155	>	* @param reducer a commutative associative combining function
4156	>	* @return the result of accumulating the given transformation
4157	>	* of all keys
4158	>	*/
4159	>	public long reduceKeysToLongInParallel
4160	>	(ToLongFunction<? super K> transformer,
4161	>	long basis,
4162	>	LongBinaryOperator reducer) {
4163	>	return ForkJoinTasks.reduceKeysToLong
4164	>	(this, transformer, basis, reducer).invoke();
4165	>	}
4166	>
4167	>	/**
4168	>	* Returns the result of accumulating the given transformation
4169	>	* of all keys using the given reducer to combine values, and
4170	>	* the given basis as an identity value.
4171	>	*
4172	>	* @param transformer a function returning the transformation
4173	>	* for an element
4174	>	* @param basis the identity (initial default value) for the reduction
4175	>	* @param reducer a commutative associative combining function
4176	>	* @return the result of accumulating the given transformation
4177	>	* of all keys
4178	>	*/
4179	>	public int reduceKeysToIntInParallel
4180	>	(ToIntFunction<? super K> transformer,
4181	>	int basis,
4182	>	IntBinaryOperator reducer) {
4183	>	return ForkJoinTasks.reduceKeysToInt
4184	>	(this, transformer, basis, reducer).invoke();
4185	>	}
4186	>
4187	>	/**
4188	>	* Performs the given action for each value.
4189	>	*
4190	>	* @param action the action
4191	>	*/
4192	>	public void forEachValueInParallel(Consumer<? super V> action) {
4193	>	ForkJoinTasks.forEachValue
4194	>	(this, action).invoke();
4195	>	}
4196	>
4197	>	/**
4198	>	* Performs the given action for each non-null transformation
4199	>	* of each value.
4200	>	*
4201	>	* @param transformer a function returning the transformation
4202	>	* for an element, or null if there is no transformation (in
4203	>	* which case the action is not applied)
4204	>	* @param action the action
4205	>	*/
4206	>	public <U> void forEachValueInParallel
4207	>	(Function<? super V, ? extends U> transformer,
4208	>	Consumer<? super U> action) {
4209	>	ForkJoinTasks.forEachValue
4210	>	(this, transformer, action).invoke();
4211	>	}
4212	>
4213	>	/**
4214	>	* Returns a non-null result from applying the given search
4215	>	* function on each value, or null if none.  Upon success,
4216	>	* further element processing is suppressed and the results of
4217	>	* any other parallel invocations of the search function are
4218	>	* ignored.
4219	>	*
4220	>	* @param searchFunction a function returning a non-null
4221	>	* result on success, else null
4222	>	* @return a non-null result from applying the given search
4223	>	* function on each value, or null if none
4224	>	*/
4225	>	public <U> U searchValuesInParallel
4226	>	(Function<? super V, ? extends U> searchFunction) {
4227	>	return ForkJoinTasks.searchValues
4228	>	(this, searchFunction).invoke();
4229	>	}
4230	>
4231	>	/**
4232	>	* Returns the result of accumulating all values using the
4233	>	* given reducer to combine values, or null if none.
4234	>	*
4235	>	* @param reducer a commutative associative combining function
4236	>	* @return the result of accumulating all values
4237	>	*/
4238	>	public V reduceValuesInParallel
4239	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
4240	>	return ForkJoinTasks.reduceValues
4241	>	(this, reducer).invoke();
4242	>	}
4243	>
4244	>	/**
4245	>	* Returns the result of accumulating the given transformation
4246	>	* of all values using the given reducer to combine values, or
4247	>	* null if none.
4248	>	*
4249	>	* @param transformer a function returning the transformation
4250	>	* for an element, or null if there is no transformation (in
4251	>	* which case it is not combined)
4252	>	* @param reducer a commutative associative combining function
4253	>	* @return the result of accumulating the given transformation
4254	>	* of all values
4255	>	*/
4256	>	public <U> U reduceValuesInParallel
4257	>	(Function<? super V, ? extends U> transformer,
4258	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4259	>	return ForkJoinTasks.reduceValues
4260	>	(this, transformer, reducer).invoke();
4261	>	}
4262	>
4263	>	/**
4264	>	* Returns the result of accumulating the given transformation
4265	>	* of all values using the given reducer to combine values,
4266	>	* and the given basis as an identity value.
4267	>	*
4268	>	* @param transformer a function returning the transformation
4269	>	* for an element
4270	>	* @param basis the identity (initial default value) for the reduction
4271	>	* @param reducer a commutative associative combining function
4272	>	* @return the result of accumulating the given transformation
4273	>	* of all values
4274	>	*/
4275	>	public double reduceValuesToDoubleInParallel
4276	>	(ToDoubleFunction<? super V> transformer,
4277	>	double basis,
4278	>	DoubleBinaryOperator reducer) {
4279	>	return ForkJoinTasks.reduceValuesToDouble
4280	>	(this, transformer, basis, reducer).invoke();
4281	>	}
4282	>
4283	>	/**
4284	>	* Returns the result of accumulating the given transformation
4285	>	* of all values using the given reducer to combine values,
4286	>	* and the given basis as an identity value.
4287	>	*
4288	>	* @param transformer a function returning the transformation
4289	>	* for an element
4290	>	* @param basis the identity (initial default value) for the reduction
4291	>	* @param reducer a commutative associative combining function
4292	>	* @return the result of accumulating the given transformation
4293	>	* of all values
4294	>	*/
4295	>	public long reduceValuesToLongInParallel
4296	>	(ToLongFunction<? super V> transformer,
4297	>	long basis,
4298	>	LongBinaryOperator reducer) {
4299	>	return ForkJoinTasks.reduceValuesToLong
4300	>	(this, transformer, basis, reducer).invoke();
4301	>	}
4302	>
4303	>	/**
4304	>	* Returns the result of accumulating the given transformation
4305	>	* of all values using the given reducer to combine values,
4306	>	* and the given basis as an identity value.
4307	>	*
4308	>	* @param transformer a function returning the transformation
4309	>	* for an element
4310	>	* @param basis the identity (initial default value) for the reduction
4311	>	* @param reducer a commutative associative combining function
4312	>	* @return the result of accumulating the given transformation
4313	>	* of all values
4314	>	*/
4315	>	public int reduceValuesToIntInParallel
4316	>	(ToIntFunction<? super V> transformer,
4317	>	int basis,
4318	>	IntBinaryOperator reducer) {
4319	>	return ForkJoinTasks.reduceValuesToInt
4320	>	(this, transformer, basis, reducer).invoke();
4321	>	}
4322	>
4323	>	/**
4324	>	* Performs the given action for each entry.
4325	>	*
4326	>	* @param action the action
4327	>	*/
4328	>	public void forEachEntryInParallel(Consumer<? super Map.Entry<K,V>> action) {
4329	>	ForkJoinTasks.forEachEntry
4330	>	(this, action).invoke();
4331	>	}
4332	>
4333	>	/**
4334	>	* Performs the given action for each non-null transformation
4335	>	* of each entry.
4336	>	*
4337	>	* @param transformer a function returning the transformation
4338	>	* for an element, or null if there is no transformation (in
4339	>	* which case the action is not applied)
4340	>	* @param action the action
4341	>	*/
4342	>	public <U> void forEachEntryInParallel
4343	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4344	>	Consumer<? super U> action) {
4345	>	ForkJoinTasks.forEachEntry
4346	>	(this, transformer, action).invoke();
4347	>	}
4348	>
4349	>	/**
4350	>	* Returns a non-null result from applying the given search
4351	>	* function on each entry, or null if none.  Upon success,
4352	>	* further element processing is suppressed and the results of
4353	>	* any other parallel invocations of the search function are
4354	>	* ignored.
4355	>	*
4356	>	* @param searchFunction a function returning a non-null
4357	>	* result on success, else null
4358	>	* @return a non-null result from applying the given search
4359	>	* function on each entry, or null if none
4360	>	*/
4361	>	public <U> U searchEntriesInParallel
4362	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4363	>	return ForkJoinTasks.searchEntries
4364	>	(this, searchFunction).invoke();
4365	>	}
4366	>
4367	>	/**
4368	>	* Returns the result of accumulating all entries using the
4369	>	* given reducer to combine values, or null if none.
4370	>	*
4371	>	* @param reducer a commutative associative combining function
4372	>	* @return the result of accumulating all entries
4373	>	*/
4374	>	public Map.Entry<K,V> reduceEntriesInParallel
4375	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4376	>	return ForkJoinTasks.reduceEntries
4377	>	(this, reducer).invoke();
4378	>	}
4379	>
4380	>	/**
4381	>	* Returns the result of accumulating the given transformation
4382	>	* of all entries using the given reducer to combine values,
4383	>	* or null if none.
4384	>	*
4385	>	* @param transformer a function returning the transformation
4386	>	* for an element, or null if there is no transformation (in
4387	>	* which case it is not combined)
4388	>	* @param reducer a commutative associative combining function
4389	>	* @return the result of accumulating the given transformation
4390	>	* of all entries
4391	>	*/
4392	>	public <U> U reduceEntriesInParallel
4393	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4394	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4395	>	return ForkJoinTasks.reduceEntries
4396	>	(this, transformer, reducer).invoke();
4397	>	}
4398	>
4399	>	/**
4400	>	* Returns the result of accumulating the given transformation
4401	>	* of all entries using the given reducer to combine values,
4402	>	* and the given basis as an identity value.
4403	>	*
4404	>	* @param transformer a function returning the transformation
4405	>	* for an element
4406	>	* @param basis the identity (initial default value) for the reduction
4407	>	* @param reducer a commutative associative combining function
4408	>	* @return the result of accumulating the given transformation
4409	>	* of all entries
4410	>	*/
4411	>	public double reduceEntriesToDoubleInParallel
4412	>	(ToDoubleFunction<Map.Entry<K,V>> transformer,
4413	>	double basis,
4414	>	DoubleBinaryOperator reducer) {
4415	>	return ForkJoinTasks.reduceEntriesToDouble
4416	>	(this, transformer, basis, reducer).invoke();
4417	>	}
4418	>
4419	>	/**
4420	>	* Returns the result of accumulating the given transformation
4421	>	* of all entries using the given reducer to combine values,
4422	>	* and the given basis as an identity value.
4423	>	*
4424	>	* @param transformer a function returning the transformation
4425	>	* for an element
4426	>	* @param basis the identity (initial default value) for the reduction
4427	>	* @param reducer a commutative associative combining function
4428	>	* @return the result of accumulating the given transformation
4429	>	* of all entries
4430	>	*/
4431	>	public long reduceEntriesToLongInParallel
4432	>	(ToLongFunction<Map.Entry<K,V>> transformer,
4433	>	long basis,
4434	>	LongBinaryOperator reducer) {
4435	>	return ForkJoinTasks.reduceEntriesToLong
4436	>	(this, transformer, basis, reducer).invoke();
4437	>	}
4438	>
4439	>	/**
4440	>	* Returns the result of accumulating the given transformation
4441	>	* of all entries using the given reducer to combine values,
4442	>	* and the given basis as an identity value.
4443	>	*
4444	>	* @param transformer a function returning the transformation
4445	>	* for an element
4446	>	* @param basis the identity (initial default value) for the reduction
4447	>	* @param reducer a commutative associative combining function
4448	>	* @return the result of accumulating the given transformation
4449	>	* of all entries
4450	>	*/
4451	>	public int reduceEntriesToIntInParallel
4452	>	(ToIntFunction<Map.Entry<K,V>> transformer,
4453	>	int basis,
4454	>	IntBinaryOperator reducer) {
4455	>	return ForkJoinTasks.reduceEntriesToInt
4456	>	(this, transformer, basis, reducer).invoke();
4457	>	}
4458	>
4459	>
4460	>	/* ----------------Views -------------- */
4461	>
4462	>	/**
4463	>	* Base class for views.
4464	>	*/
4465	>	abstract static class CHMCollectionView<K,V,E>
4466	>	implements Collection<E>, java.io.Serializable {
4467	>	private static final long serialVersionUID = 7249069246763182397L;
4468	>	final ConcurrentHashMap<K,V> map;
4469	>	CHMCollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4470	>
4471	>	/**
4472	>	* Returns the map backing this view.
4473	>	*
4474	>	* @return the map backing this view
4475	>	*/
4476	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4477	>
4478	>	/**
4479	>	* Removes all of the elements from this view, by removing all
4480	>	* the mappings from the map backing this view.
4481	>	*/
4482	>	public final void clear()      { map.clear(); }
4483	>	public final int size()        { return map.size(); }
4484	>	public final boolean isEmpty() { return map.isEmpty(); }
4485	>
4486	>	// implementations below rely on concrete classes supplying these
4487	>	// abstract methods
4488	>	/**
4489	>	* Returns a "weakly consistent" iterator that will never
4490	>	* throw {@link ConcurrentModificationException}, and
4491	>	* guarantees to traverse elements as they existed upon
4492	>	* construction of the iterator, and may (but is not
4493	>	* guaranteed to) reflect any modifications subsequent to
4494	>	* construction.
4495	>	*/
4496	>	public abstract Iterator<E> iterator();
4497	>	public abstract boolean contains(Object o);
4498	>	public abstract boolean remove(Object o);
4499	>
4500	>	private static final String oomeMsg = "Required array size too large";
4501	>
4502	>	public final Object[] toArray() {
4503	>	long sz = map.mappingCount();
4504	>	if (sz > MAX_ARRAY_SIZE)
4505	>	throw new OutOfMemoryError(oomeMsg);
4506	>	int n = (int)sz;
4507	>	Object[] r = new Object[n];
4508	>	int i = 0;
4509	>	for (E e : this) {
4510	>	if (i == n) {
4511	>	if (n >= MAX_ARRAY_SIZE)
4512	>	throw new OutOfMemoryError(oomeMsg);
4513	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4514	>	n = MAX_ARRAY_SIZE;
4515	>	else
4516	>	n += (n >>> 1) + 1;
4517	>	r = Arrays.copyOf(r, n);
4518	>	}
4519	>	r[i++] = e;
4520	>	}
4521	>	return (i == n) ? r : Arrays.copyOf(r, i);
4522	>	}
4523	>
4524	>	@SuppressWarnings("unchecked")
4525	>	public final <T> T[] toArray(T[] a) {
4526	>	long sz = map.mappingCount();
4527	>	if (sz > MAX_ARRAY_SIZE)
4528	>	throw new OutOfMemoryError(oomeMsg);
4529	>	int m = (int)sz;
4530	>	T[] r = (a.length >= m) ? a :
4531	>	(T[])java.lang.reflect.Array
4532	>	.newInstance(a.getClass().getComponentType(), m);
4533	>	int n = r.length;
4534	>	int i = 0;
4535	>	for (E e : this) {
4536	>	if (i == n) {
4537	>	if (n >= MAX_ARRAY_SIZE)
4538	>	throw new OutOfMemoryError(oomeMsg);
4539	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4540	>	n = MAX_ARRAY_SIZE;
4541	>	else
4542	>	n += (n >>> 1) + 1;
4543	>	r = Arrays.copyOf(r, n);
4544	>	}
4545	>	r[i++] = (T)e;
4546	>	}
4547	>	if (a == r && i < n) {
4548	>	r[i] = null; // null-terminate
4549	>	return r;
4550	>	}
4551	>	return (i == n) ? r : Arrays.copyOf(r, i);
4552	>	}
4553	>
4554	>	/**
4555	>	* Returns a string representation of this collection.
4556	>	* The string representation consists of the string representations
4557	>	* of the collection's elements in the order they are returned by
4558	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4559	>	* Adjacent elements are separated by the characters {@code ", "}
4560	>	* (comma and space).  Elements are converted to strings as by
4561	>	* {@link String#valueOf(Object)}.
4562	>	*
4563	>	* @return a string representation of this collection
4564	>	*/
4565	>	public final String toString() {
4566	>	StringBuilder sb = new StringBuilder();
4567	>	sb.append('[');
4568	>	Iterator<E> it = iterator();
4569	>	if (it.hasNext()) {
4570	>	for (;;) {
4571	>	Object e = it.next();
4572	>	sb.append(e == this ? "(this Collection)" : e);
4573	>	if (!it.hasNext())
4574	>	break;
4575	>	sb.append(',').append(' ');
4576	>	}
4577	>	}
4578	>	return sb.append(']').toString();
4579	>	}
4580	>
4581	>	public final boolean containsAll(Collection<?> c) {
4582	>	if (c != this) {
4583	>	for (Object e : c) {
4584	>	if (e == null || !contains(e))
4585	>	return false;
4586	>	}
4587	>	}
4588	>	return true;
4589	>	}
4590	>
4591	>	public final boolean removeAll(Collection<?> c) {
4592	>	boolean modified = false;
4593	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4594	>	if (c.contains(it.next())) {
4595	>	it.remove();
4596	>	modified = true;
4597	>	}
4598	>	}
4599	>	return modified;
4600	>	}
4601	>
4602	>	public final boolean retainAll(Collection<?> c) {
4603	>	boolean modified = false;
4604	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4605	>	if (!c.contains(it.next())) {
4606	>	it.remove();
4607	>	modified = true;
4608	>	}
4609	>	}
4610	>	return modified;
4611	>	}
4612	>
4613	>	}
4614	>
4615	>	abstract static class CHMSetView<K,V,E>
4616	>	extends CHMCollectionView<K,V,E>
4617	>	implements Set<E>, java.io.Serializable {
4618	>	private static final long serialVersionUID = 7249069246763182397L;
4619	>	CHMSetView(ConcurrentHashMap<K,V> map) { super(map); }
4620	>
4621	>	// Implement Set API
4622	>
4623	>	/**
4624	>	* Implements {@link Set#hashCode()}.
4625	>	* @return the hash code value for this set
4626	>	*/
4627	>	public final int hashCode() {
4628	>	int h = 0;
4629	>	for (E e : this)
4630	>	h += e.hashCode();
4631	>	return h;
4632	>	}
4633	>
4634	>	/**
4635	>	* Implements {@link Set#equals(Object)}.
4636	>	* @param o object to be compared for equality with this set
4637	>	* @return {@code true} if the specified object is equal to this set
4638	>	*/
4639	>	public final boolean equals(Object o) {
4640	>	Set<?> c;
4641	>	return ((o instanceof Set) &&
4642	>	((c = (Set<?>)o) == this ||
4643	>	(containsAll(c) && c.containsAll(this))));
4644	>	}
4645	>	}
4646	>
4647	>	/**
4648	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4649	>	* which additions may optionally be enabled by mapping to a
4650	>	* common value.  This class cannot be directly instantiated.
4651	>	* See {@link #keySet() keySet()},
4652	>	* {@link #keySet(Object) keySet(V)},
4653	>	* {@link #newKeySet() newKeySet()},
4654	>	* {@link #newKeySet(int) newKeySet(int)}.
4655	>	*/
4656	>	public static class KeySetView<K,V>
4657	>	extends CHMSetView<K,V,K>
4658	>	implements Set<K>, java.io.Serializable {
4659	>	private static final long serialVersionUID = 7249069246763182397L;
4660	>	private final V value;
4661	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4662	>	super(map);
4663	>	this.value = value;
4664	>	}
4665	>
4666	>	/**
4667	>	* Returns the default mapped value for additions,
4668	>	* or {@code null} if additions are not supported.
4669	>	*
4670	>	* @return the default mapped value for additions, or {@code null}
4671	>	* if not supported
4672	>	*/
4673	>	public V getMappedValue() { return value; }
4674	>
4675	>	/**
4676	>	* {@inheritDoc}
4677	>	* @throws NullPointerException if the specified key is null
4678	>	*/
4679	>	public boolean contains(Object o) { return map.containsKey(o); }
4680	>
4681	>	/**
4682	>	* Removes the key from this map view, by removing the key (and its
4683	>	* corresponding value) from the backing map.  This method does
4684	>	* nothing if the key is not in the map.
4685	>	*
4686	>	* @param  o the key to be removed from the backing map
4687	>	* @return {@code true} if the backing map contained the specified key
4688	>	* @throws NullPointerException if the specified key is null
4689	>	*/
4690	>	public boolean remove(Object o) { return map.remove(o) != null; }
4691	>
4692	>	/**
4693	>	* @return an iterator over the keys of the backing map
4694	>	*/
4695	>	public Iterator<K> iterator() { return new KeyIterator<K,V>(map); }
4696	>
4697	>	/**
4698	>	* Adds the specified key to this set view by mapping the key to
4699	>	* the default mapped value in the backing map, if defined.
4700	>	*
4701	>	* @param e key to be added
4702	>	* @return {@code true} if this set changed as a result of the call
4703	>	* @throws NullPointerException if the specified key is null
4704	>	* @throws UnsupportedOperationException if no default mapped value
4705	>	* for additions was provided
4706	>	*/
4707	>	public boolean add(K e) {
4708	>	V v;
4709	>	if ((v = value) == null)
4710	>	throw new UnsupportedOperationException();
4711	>	return map.internalPut(e, v, true) == null;
4712	>	}
4713	>
4714	>	/**
4715	>	* Adds all of the elements in the specified collection to this set,
4716	>	* as if by calling {@link #add} on each one.
4717	>	*
4718	>	* @param c the elements to be inserted into this set
4719	>	* @return {@code true} if this set changed as a result of the call
4720	>	* @throws NullPointerException if the collection or any of its
4721	>	* elements are {@code null}
4722	>	* @throws UnsupportedOperationException if no default mapped value
4723	>	* for additions was provided
4724	>	*/
4725	>	public boolean addAll(Collection<? extends K> c) {
4726	>	boolean added = false;
4727	>	V v;
4728	>	if ((v = value) == null)
4729	>	throw new UnsupportedOperationException();
4730	>	for (K e : c) {
4731	>	if (map.internalPut(e, v, true) == null)
4732	>	added = true;
4733	>	}
4734	>	return added;
4735	>	}
4736	>
4737	>	public Stream<K> stream() {
4738	>	return Streams.stream(() -> new KeyIterator<K,V>(map), 0);
4739	>	}
4740	>	public Stream<K> parallelStream() {
4741	>	return Streams.parallelStream(() -> new KeyIterator<K,V>(map, null),
4742	>	0);
4743	>	}
4744	>	}
4745	>
4746	>	/**
4747	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4748	>	* values, in which additions are disabled. This class cannot be
4749	>	* directly instantiated. See {@link #values()}.
4750	>	*
4751	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
4752	>	* that will never throw {@link ConcurrentModificationException},
4753	>	* and guarantees to traverse elements as they existed upon
4754	>	* construction of the iterator, and may (but is not guaranteed to)
4755	>	* reflect any modifications subsequent to construction.
4756	>	*/
4757	>	public static final class ValuesView<K,V>
4758	>	extends CHMCollectionView<K,V,V>
4759	>	implements Collection<V>, java.io.Serializable {
4760	>	private static final long serialVersionUID = 2249069246763182397L;
4761	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4762	>	public final boolean contains(Object o) {
4763	>	return map.containsValue(o);
4764	>	}
4765	>	public final boolean remove(Object o) {
4766	>	if (o != null) {
4767	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4768	>	if (o.equals(it.next())) {
4769	>	it.remove();
4770	>	return true;
4771		}
4772		}
1427	–	} finally {
1428	–	seg.unlock();
4773		}
4774	+	return false;
4775		}
4776	<	s.writeObject(null);
4777	<	s.writeObject(null);
4776	>
4777	>	/**
4778	>	* @return an iterator over the values of the backing map
4779	>	*/
4780	>	public final Iterator<V> iterator() {
4781	>	return new ValueIterator<K,V>(map);
4782	>	}
4783	>
4784	>	/** Always throws {@link UnsupportedOperationException}. */
4785	>	public final boolean add(V e) {
4786	>	throw new UnsupportedOperationException();
4787	>	}
4788	>	/** Always throws {@link UnsupportedOperationException}. */
4789	>	public final boolean addAll(Collection<? extends V> c) {
4790	>	throw new UnsupportedOperationException();
4791	>	}
4792	>
4793	>	public Stream<V> stream() {
4794	>	return Streams.stream(() -> new ValueIterator<K,V>(map), 0);
4795	>	}
4796	>
4797	>	public Stream<V> parallelStream() {
4798	>	return Streams.parallelStream(() -> new ValueIterator<K,V>(map, null),
4799	>	0);
4800	>	}
4801	>
4802		}
4803
4804		/**
4805	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
4806	<	* stream (i.e., deserializes it).
4807	<	* @param s the stream
4805	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4806	>	* entries.  This class cannot be directly instantiated. See
4807	>	* {@link #entrySet()}.
4808		*/
4809	<	@SuppressWarnings("unchecked")
4810	<	private void readObject(java.io.ObjectInputStream s)
4811	<	throws IOException, ClassNotFoundException {
4812	<	s.defaultReadObject();
4809	>	public static final class EntrySetView<K,V>
4810	>	extends CHMSetView<K,V,Map.Entry<K,V>>
4811	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4812	>	private static final long serialVersionUID = 2249069246763182397L;
4813	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4814	>
4815	>	public final boolean contains(Object o) {
4816	>	Object k, v, r; Map.Entry<?,?> e;
4817	>	return ((o instanceof Map.Entry) &&
4818	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4819	>	(r = map.get(k)) != null &&
4820	>	(v = e.getValue()) != null &&
4821	>	(v == r || v.equals(r)));
4822	>	}
4823	>	public final boolean remove(Object o) {
4824	>	Object k, v; Map.Entry<?,?> e;
4825	>	return ((o instanceof Map.Entry) &&
4826	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4827	>	(v = e.getValue()) != null &&
4828	>	map.remove(k, v));
4829	>	}
4830	>
4831	>	/**
4832	>	* @return an iterator over the entries of the backing map
4833	>	*/
4834	>	public final Iterator<Map.Entry<K,V>> iterator() {
4835	>	return new EntryIterator<K,V>(map);
4836	>	}
4837	>
4838	>	/**
4839	>	* Adds the specified mapping to this view.
4840	>	*
4841	>	* @param e mapping to be added
4842	>	* @return {@code true} if this set changed as a result of the call
4843	>	* @throws NullPointerException if the entry, its key, or its
4844	>	* value is null
4845	>	*/
4846	>	public final boolean add(Entry<K,V> e) {
4847	>	return map.internalPut(e.getKey(), e.getValue(), false) == null;
4848	>	}
4849	>	/**
4850	>	* Adds all of the mappings in the specified collection to this
4851	>	* set, as if by calling {@link #add(Map.Entry)} on each one.
4852	>	* @param c the mappings to be inserted into this set
4853	>	* @return {@code true} if this set changed as a result of the call
4854	>	* @throws NullPointerException if the collection or any of its
4855	>	* entries, keys, or values are null
4856	>	*/
4857	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
4858	>	boolean added = false;
4859	>	for (Entry<K,V> e : c) {
4860	>	if (add(e))
4861	>	added = true;
4862	>	}
4863	>	return added;
4864	>	}
4865	>
4866	>	public Stream<Map.Entry<K,V>> stream() {
4867	>	return Streams.stream(() -> new EntryIterator<K,V>(map), 0);
4868	>	}
4869	>
4870	>	public Stream<Map.Entry<K,V>> parallelStream() {
4871	>	return Streams.parallelStream(() -> new EntryIterator<K,V>(map, null),
4872	>	0);
4873	>	}
4874	>	}
4875	>
4876	>	// ---------------------------------------------------------------------
4877	>
4878	>	/**
4879	>	* Predefined tasks for performing bulk parallel operations on
4880	>	* ConcurrentHashMaps. These tasks follow the forms and rules used
4881	>	* for bulk operations. Each method has the same name, but returns
4882	>	* a task rather than invoking it. These methods may be useful in
4883	>	* custom applications such as submitting a task without waiting
4884	>	* for completion, using a custom pool, or combining with other
4885	>	* tasks.
4886	>	*/
4887	>	public static class ForkJoinTasks {
4888	>	private ForkJoinTasks() {}
4889	>
4890	>	/**
4891	>	* Returns a task that when invoked, performs the given
4892	>	* action for each (key, value)
4893	>	*
4894	>	* @param map the map
4895	>	* @param action the action
4896	>	* @return the task
4897	>	*/
4898	>	public static <K,V> ForkJoinTask<Void> forEach
4899	>	(ConcurrentHashMap<K,V> map,
4900	>	BiConsumer<? super K, ? super V> action) {
4901	>	if (action == null) throw new NullPointerException();
4902	>	return new ForEachMappingTask<K,V>(map, null, -1, action);
4903	>	}
4904	>
4905	>	/**
4906	>	* Returns a task that when invoked, performs the given
4907	>	* action for each non-null transformation of each (key, value)
4908	>	*
4909	>	* @param map the map
4910	>	* @param transformer a function returning the transformation
4911	>	* for an element, or null if there is no transformation (in
4912	>	* which case the action is not applied)
4913	>	* @param action the action
4914	>	* @return the task
4915	>	*/
4916	>	public static <K,V,U> ForkJoinTask<Void> forEach
4917	>	(ConcurrentHashMap<K,V> map,
4918	>	BiFunction<? super K, ? super V, ? extends U> transformer,
4919	>	Consumer<? super U> action) {
4920	>	if (transformer == null || action == null)
4921	>	throw new NullPointerException();
4922	>	return new ForEachTransformedMappingTask<K,V,U>
4923	>	(map, null, -1, transformer, action);
4924	>	}
4925	>
4926	>	/**
4927	>	* Returns a task that when invoked, returns a non-null result
4928	>	* from applying the given search function on each (key,
4929	>	* value), or null if none. Upon success, further element
4930	>	* processing is suppressed and the results of any other
4931	>	* parallel invocations of the search function are ignored.
4932	>	*
4933	>	* @param map the map
4934	>	* @param searchFunction a function returning a non-null
4935	>	* result on success, else null
4936	>	* @return the task
4937	>	*/
4938	>	public static <K,V,U> ForkJoinTask<U> search
4939	>	(ConcurrentHashMap<K,V> map,
4940	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
4941	>	if (searchFunction == null) throw new NullPointerException();
4942	>	return new SearchMappingsTask<K,V,U>
4943	>	(map, null, -1, searchFunction,
4944	>	new AtomicReference<U>());
4945	>	}
4946	>
4947	>	/**
4948	>	* Returns a task that when invoked, returns the result of
4949	>	* accumulating the given transformation of all (key, value) pairs
4950	>	* using the given reducer to combine values, or null if none.
4951	>	*
4952	>	* @param map the map
4953	>	* @param transformer a function returning the transformation
4954	>	* for an element, or null if there is no transformation (in
4955	>	* which case it is not combined)
4956	>	* @param reducer a commutative associative combining function
4957	>	* @return the task
4958	>	*/
4959	>	public static <K,V,U> ForkJoinTask<U> reduce
4960	>	(ConcurrentHashMap<K,V> map,
4961	>	BiFunction<? super K, ? super V, ? extends U> transformer,
4962	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4963	>	if (transformer == null || reducer == null)
4964	>	throw new NullPointerException();
4965	>	return new MapReduceMappingsTask<K,V,U>
4966	>	(map, null, -1, null, transformer, reducer);
4967	>	}
4968	>
4969	>	/**
4970	>	* Returns a task that when invoked, returns the result of
4971	>	* accumulating the given transformation of all (key, value) pairs
4972	>	* using the given reducer to combine values, and the given
4973	>	* basis as an identity value.
4974	>	*
4975	>	* @param map the map
4976	>	* @param transformer a function returning the transformation
4977	>	* for an element
4978	>	* @param basis the identity (initial default value) for the reduction
4979	>	* @param reducer a commutative associative combining function
4980	>	* @return the task
4981	>	*/
4982	>	public static <K,V> ForkJoinTask<Double> reduceToDouble
4983	>	(ConcurrentHashMap<K,V> map,
4984	>	ToDoubleBiFunction<? super K, ? super V> transformer,
4985	>	double basis,
4986	>	DoubleBinaryOperator reducer) {
4987	>	if (transformer == null || reducer == null)
4988	>	throw new NullPointerException();
4989	>	return new MapReduceMappingsToDoubleTask<K,V>
4990	>	(map, null, -1, null, transformer, basis, reducer);
4991	>	}
4992	>
4993	>	/**
4994	>	* Returns a task that when invoked, returns the result of
4995	>	* accumulating the given transformation of all (key, value) pairs
4996	>	* using the given reducer to combine values, and the given
4997	>	* basis as an identity value.
4998	>	*
4999	>	* @param map the map
5000	>	* @param transformer a function returning the transformation
5001	>	* for an element
5002	>	* @param basis the identity (initial default value) for the reduction
5003	>	* @param reducer a commutative associative combining function
5004	>	* @return the task
5005	>	*/
5006	>	public static <K,V> ForkJoinTask<Long> reduceToLong
5007	>	(ConcurrentHashMap<K,V> map,
5008	>	ToLongBiFunction<? super K, ? super V> transformer,
5009	>	long basis,
5010	>	LongBinaryOperator reducer) {
5011	>	if (transformer == null || reducer == null)
5012	>	throw new NullPointerException();
5013	>	return new MapReduceMappingsToLongTask<K,V>
5014	>	(map, null, -1, null, transformer, basis, reducer);
5015	>	}
5016
5017	<	// Re-initialize segments to be minimally sized, and let grow.
5018	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
5019	<	final Segment<K,V>[] segments = this.segments;
5020	<	for (int k = 0; k < segments.length; ++k) {
5021	<	Segment<K,V> seg = segments[k];
5022	<	if (seg != null) {
5023	<	seg.threshold = (int)(cap * seg.loadFactor);
5024	<	seg.table = (HashEntry<K,V>[]) new HashEntry[cap];
5017	>	/**
5018	>	* Returns a task that when invoked, returns the result of
5019	>	* accumulating the given transformation of all (key, value) pairs
5020	>	* using the given reducer to combine values, and the given
5021	>	* basis as an identity value.
5022	>	*
5023	>	* @param map the map
5024	>	* @param transformer a function returning the transformation
5025	>	* for an element
5026	>	* @param basis the identity (initial default value) for the reduction
5027	>	* @param reducer a commutative associative combining function
5028	>	* @return the task
5029	>	*/
5030	>	public static <K,V> ForkJoinTask<Integer> reduceToInt
5031	>	(ConcurrentHashMap<K,V> map,
5032	>	ToIntBiFunction<? super K, ? super V> transformer,
5033	>	int basis,
5034	>	IntBinaryOperator reducer) {
5035	>	if (transformer == null || reducer == null)
5036	>	throw new NullPointerException();
5037	>	return new MapReduceMappingsToIntTask<K,V>
5038	>	(map, null, -1, null, transformer, basis, reducer);
5039	>	}
5040	>
5041	>	/**
5042	>	* Returns a task that when invoked, performs the given action
5043	>	* for each key.
5044	>	*
5045	>	* @param map the map
5046	>	* @param action the action
5047	>	* @return the task
5048	>	*/
5049	>	public static <K,V> ForkJoinTask<Void> forEachKey
5050	>	(ConcurrentHashMap<K,V> map,
5051	>	Consumer<? super K> action) {
5052	>	if (action == null) throw new NullPointerException();
5053	>	return new ForEachKeyTask<K,V>(map, null, -1, action);
5054	>	}
5055	>
5056	>	/**
5057	>	* Returns a task that when invoked, performs the given action
5058	>	* for each non-null transformation of each key.
5059	>	*
5060	>	* @param map the map
5061	>	* @param transformer a function returning the transformation
5062	>	* for an element, or null if there is no transformation (in
5063	>	* which case the action is not applied)
5064	>	* @param action the action
5065	>	* @return the task
5066	>	*/
5067	>	public static <K,V,U> ForkJoinTask<Void> forEachKey
5068	>	(ConcurrentHashMap<K,V> map,
5069	>	Function<? super K, ? extends U> transformer,
5070	>	Consumer<? super U> action) {
5071	>	if (transformer == null || action == null)
5072	>	throw new NullPointerException();
5073	>	return new ForEachTransformedKeyTask<K,V,U>
5074	>	(map, null, -1, transformer, action);
5075	>	}
5076	>
5077	>	/**
5078	>	* Returns a task that when invoked, returns a non-null result
5079	>	* from applying the given search function on each key, or
5080	>	* null if none.  Upon success, further element processing is
5081	>	* suppressed and the results of any other parallel
5082	>	* invocations of the search function are ignored.
5083	>	*
5084	>	* @param map the map
5085	>	* @param searchFunction a function returning a non-null
5086	>	* result on success, else null
5087	>	* @return the task
5088	>	*/
5089	>	public static <K,V,U> ForkJoinTask<U> searchKeys
5090	>	(ConcurrentHashMap<K,V> map,
5091	>	Function<? super K, ? extends U> searchFunction) {
5092	>	if (searchFunction == null) throw new NullPointerException();
5093	>	return new SearchKeysTask<K,V,U>
5094	>	(map, null, -1, searchFunction,
5095	>	new AtomicReference<U>());
5096	>	}
5097	>
5098	>	/**
5099	>	* Returns a task that when invoked, returns the result of
5100	>	* accumulating all keys using the given reducer to combine
5101	>	* values, or null if none.
5102	>	*
5103	>	* @param map the map
5104	>	* @param reducer a commutative associative combining function
5105	>	* @return the task
5106	>	*/
5107	>	public static <K,V> ForkJoinTask<K> reduceKeys
5108	>	(ConcurrentHashMap<K,V> map,
5109	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5110	>	if (reducer == null) throw new NullPointerException();
5111	>	return new ReduceKeysTask<K,V>
5112	>	(map, null, -1, null, reducer);
5113	>	}
5114	>
5115	>	/**
5116	>	* Returns a task that when invoked, returns the result of
5117	>	* accumulating the given transformation of all keys using the given
5118	>	* reducer to combine values, or null if none.
5119	>	*
5120	>	* @param map the map
5121	>	* @param transformer a function returning the transformation
5122	>	* for an element, or null if there is no transformation (in
5123	>	* which case it is not combined)
5124	>	* @param reducer a commutative associative combining function
5125	>	* @return the task
5126	>	*/
5127	>	public static <K,V,U> ForkJoinTask<U> reduceKeys
5128	>	(ConcurrentHashMap<K,V> map,
5129	>	Function<? super K, ? extends U> transformer,
5130	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5131	>	if (transformer == null || reducer == null)
5132	>	throw new NullPointerException();
5133	>	return new MapReduceKeysTask<K,V,U>
5134	>	(map, null, -1, null, transformer, reducer);
5135	>	}
5136	>
5137	>	/**
5138	>	* Returns a task that when invoked, returns the result of
5139	>	* accumulating the given transformation of all keys using the given
5140	>	* reducer to combine values, and the given basis as an
5141	>	* identity value.
5142	>	*
5143	>	* @param map the map
5144	>	* @param transformer a function returning the transformation
5145	>	* for an element
5146	>	* @param basis the identity (initial default value) for the reduction
5147	>	* @param reducer a commutative associative combining function
5148	>	* @return the task
5149	>	*/
5150	>	public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
5151	>	(ConcurrentHashMap<K,V> map,
5152	>	ToDoubleFunction<? super K> transformer,
5153	>	double basis,
5154	>	DoubleBinaryOperator reducer) {
5155	>	if (transformer == null || reducer == null)
5156	>	throw new NullPointerException();
5157	>	return new MapReduceKeysToDoubleTask<K,V>
5158	>	(map, null, -1, null, transformer, basis, reducer);
5159	>	}
5160	>
5161	>	/**
5162	>	* Returns a task that when invoked, returns the result of
5163	>	* accumulating the given transformation of all keys using the given
5164	>	* reducer to combine values, and the given basis as an
5165	>	* identity value.
5166	>	*
5167	>	* @param map the map
5168	>	* @param transformer a function returning the transformation
5169	>	* for an element
5170	>	* @param basis the identity (initial default value) for the reduction
5171	>	* @param reducer a commutative associative combining function
5172	>	* @return the task
5173	>	*/
5174	>	public static <K,V> ForkJoinTask<Long> reduceKeysToLong
5175	>	(ConcurrentHashMap<K,V> map,
5176	>	ToLongFunction<? super K> transformer,
5177	>	long basis,
5178	>	LongBinaryOperator reducer) {
5179	>	if (transformer == null || reducer == null)
5180	>	throw new NullPointerException();
5181	>	return new MapReduceKeysToLongTask<K,V>
5182	>	(map, null, -1, null, transformer, basis, reducer);
5183	>	}
5184	>
5185	>	/**
5186	>	* Returns a task that when invoked, returns the result of
5187	>	* accumulating the given transformation of all keys using the given
5188	>	* reducer to combine values, and the given basis as an
5189	>	* identity value.
5190	>	*
5191	>	* @param map the map
5192	>	* @param transformer a function returning the transformation
5193	>	* for an element
5194	>	* @param basis the identity (initial default value) for the reduction
5195	>	* @param reducer a commutative associative combining function
5196	>	* @return the task
5197	>	*/
5198	>	public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
5199	>	(ConcurrentHashMap<K,V> map,
5200	>	ToIntFunction<? super K> transformer,
5201	>	int basis,
5202	>	IntBinaryOperator reducer) {
5203	>	if (transformer == null || reducer == null)
5204	>	throw new NullPointerException();
5205	>	return new MapReduceKeysToIntTask<K,V>
5206	>	(map, null, -1, null, transformer, basis, reducer);
5207	>	}
5208	>
5209	>	/**
5210	>	* Returns a task that when invoked, performs the given action
5211	>	* for each value.
5212	>	*
5213	>	* @param map the map
5214	>	* @param action the action
5215	>	* @return the task
5216	>	*/
5217	>	public static <K,V> ForkJoinTask<Void> forEachValue
5218	>	(ConcurrentHashMap<K,V> map,
5219	>	Consumer<? super V> action) {
5220	>	if (action == null) throw new NullPointerException();
5221	>	return new ForEachValueTask<K,V>(map, null, -1, action);
5222	>	}
5223	>
5224	>	/**
5225	>	* Returns a task that when invoked, performs the given action
5226	>	* for each non-null transformation of each value.
5227	>	*
5228	>	* @param map the map
5229	>	* @param transformer a function returning the transformation
5230	>	* for an element, or null if there is no transformation (in
5231	>	* which case the action is not applied)
5232	>	* @param action the action
5233	>	* @return the task
5234	>	*/
5235	>	public static <K,V,U> ForkJoinTask<Void> forEachValue
5236	>	(ConcurrentHashMap<K,V> map,
5237	>	Function<? super V, ? extends U> transformer,
5238	>	Consumer<? super U> action) {
5239	>	if (transformer == null || action == null)
5240	>	throw new NullPointerException();
5241	>	return new ForEachTransformedValueTask<K,V,U>
5242	>	(map, null, -1, transformer, action);
5243	>	}
5244	>
5245	>	/**
5246	>	* Returns a task that when invoked, returns a non-null result
5247	>	* from applying the given search function on each value, or
5248	>	* null if none.  Upon success, further element processing is
5249	>	* suppressed and the results of any other parallel
5250	>	* invocations of the search function are ignored.
5251	>	*
5252	>	* @param map the map
5253	>	* @param searchFunction a function returning a non-null
5254	>	* result on success, else null
5255	>	* @return the task
5256	>	*/
5257	>	public static <K,V,U> ForkJoinTask<U> searchValues
5258	>	(ConcurrentHashMap<K,V> map,
5259	>	Function<? super V, ? extends U> searchFunction) {
5260	>	if (searchFunction == null) throw new NullPointerException();
5261	>	return new SearchValuesTask<K,V,U>
5262	>	(map, null, -1, searchFunction,
5263	>	new AtomicReference<U>());
5264	>	}
5265	>
5266	>	/**
5267	>	* Returns a task that when invoked, returns the result of
5268	>	* accumulating all values using the given reducer to combine
5269	>	* values, or null if none.
5270	>	*
5271	>	* @param map the map
5272	>	* @param reducer a commutative associative combining function
5273	>	* @return the task
5274	>	*/
5275	>	public static <K,V> ForkJoinTask<V> reduceValues
5276	>	(ConcurrentHashMap<K,V> map,
5277	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5278	>	if (reducer == null) throw new NullPointerException();
5279	>	return new ReduceValuesTask<K,V>
5280	>	(map, null, -1, null, reducer);
5281	>	}
5282	>
5283	>	/**
5284	>	* Returns a task that when invoked, returns the result of
5285	>	* accumulating the given transformation of all values using the
5286	>	* given reducer to combine values, or null if none.
5287	>	*
5288	>	* @param map the map
5289	>	* @param transformer a function returning the transformation
5290	>	* for an element, or null if there is no transformation (in
5291	>	* which case it is not combined)
5292	>	* @param reducer a commutative associative combining function
5293	>	* @return the task
5294	>	*/
5295	>	public static <K,V,U> ForkJoinTask<U> reduceValues
5296	>	(ConcurrentHashMap<K,V> map,
5297	>	Function<? super V, ? extends U> transformer,
5298	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5299	>	if (transformer == null || reducer == null)
5300	>	throw new NullPointerException();
5301	>	return new MapReduceValuesTask<K,V,U>
5302	>	(map, null, -1, null, transformer, reducer);
5303	>	}
5304	>
5305	>	/**
5306	>	* Returns a task that when invoked, returns the result of
5307	>	* accumulating the given transformation of all values using the
5308	>	* given reducer to combine values, and the given basis as an
5309	>	* identity value.
5310	>	*
5311	>	* @param map the map
5312	>	* @param transformer a function returning the transformation
5313	>	* for an element
5314	>	* @param basis the identity (initial default value) for the reduction
5315	>	* @param reducer a commutative associative combining function
5316	>	* @return the task
5317	>	*/
5318	>	public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
5319	>	(ConcurrentHashMap<K,V> map,
5320	>	ToDoubleFunction<? super V> transformer,
5321	>	double basis,
5322	>	DoubleBinaryOperator reducer) {
5323	>	if (transformer == null || reducer == null)
5324	>	throw new NullPointerException();
5325	>	return new MapReduceValuesToDoubleTask<K,V>
5326	>	(map, null, -1, null, transformer, basis, reducer);
5327	>	}
5328	>
5329	>	/**
5330	>	* Returns a task that when invoked, returns the result of
5331	>	* accumulating the given transformation of all values using the
5332	>	* given reducer to combine values, and the given basis as an
5333	>	* identity value.
5334	>	*
5335	>	* @param map the map
5336	>	* @param transformer a function returning the transformation
5337	>	* for an element
5338	>	* @param basis the identity (initial default value) for the reduction
5339	>	* @param reducer a commutative associative combining function
5340	>	* @return the task
5341	>	*/
5342	>	public static <K,V> ForkJoinTask<Long> reduceValuesToLong
5343	>	(ConcurrentHashMap<K,V> map,
5344	>	ToLongFunction<? super V> transformer,
5345	>	long basis,
5346	>	LongBinaryOperator reducer) {
5347	>	if (transformer == null || reducer == null)
5348	>	throw new NullPointerException();
5349	>	return new MapReduceValuesToLongTask<K,V>
5350	>	(map, null, -1, null, transformer, basis, reducer);
5351	>	}
5352	>
5353	>	/**
5354	>	* Returns a task that when invoked, returns the result of
5355	>	* accumulating the given transformation of all values using the
5356	>	* given reducer to combine values, and the given basis as an
5357	>	* identity value.
5358	>	*
5359	>	* @param map the map
5360	>	* @param transformer a function returning the transformation
5361	>	* for an element
5362	>	* @param basis the identity (initial default value) for the reduction
5363	>	* @param reducer a commutative associative combining function
5364	>	* @return the task
5365	>	*/
5366	>	public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
5367	>	(ConcurrentHashMap<K,V> map,
5368	>	ToIntFunction<? super V> transformer,
5369	>	int basis,
5370	>	IntBinaryOperator reducer) {
5371	>	if (transformer == null || reducer == null)
5372	>	throw new NullPointerException();
5373	>	return new MapReduceValuesToIntTask<K,V>
5374	>	(map, null, -1, null, transformer, basis, reducer);
5375	>	}
5376	>
5377	>	/**
5378	>	* Returns a task that when invoked, perform the given action
5379	>	* for each entry.
5380	>	*
5381	>	* @param map the map
5382	>	* @param action the action
5383	>	* @return the task
5384	>	*/
5385	>	public static <K,V> ForkJoinTask<Void> forEachEntry
5386	>	(ConcurrentHashMap<K,V> map,
5387	>	Consumer<? super Map.Entry<K,V>> action) {
5388	>	if (action == null) throw new NullPointerException();
5389	>	return new ForEachEntryTask<K,V>(map, null, -1, action);
5390	>	}
5391	>
5392	>	/**
5393	>	* Returns a task that when invoked, perform the given action
5394	>	* for each non-null transformation of each entry.
5395	>	*
5396	>	* @param map the map
5397	>	* @param transformer a function returning the transformation
5398	>	* for an element, or null if there is no transformation (in
5399	>	* which case the action is not applied)
5400	>	* @param action the action
5401	>	* @return the task
5402	>	*/
5403	>	public static <K,V,U> ForkJoinTask<Void> forEachEntry
5404	>	(ConcurrentHashMap<K,V> map,
5405	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5406	>	Consumer<? super U> action) {
5407	>	if (transformer == null || action == null)
5408	>	throw new NullPointerException();
5409	>	return new ForEachTransformedEntryTask<K,V,U>
5410	>	(map, null, -1, transformer, action);
5411	>	}
5412	>
5413	>	/**
5414	>	* Returns a task that when invoked, returns a non-null result
5415	>	* from applying the given search function on each entry, or
5416	>	* null if none.  Upon success, further element processing is
5417	>	* suppressed and the results of any other parallel
5418	>	* invocations of the search function are ignored.
5419	>	*
5420	>	* @param map the map
5421	>	* @param searchFunction a function returning a non-null
5422	>	* result on success, else null
5423	>	* @return the task
5424	>	*/
5425	>	public static <K,V,U> ForkJoinTask<U> searchEntries
5426	>	(ConcurrentHashMap<K,V> map,
5427	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
5428	>	if (searchFunction == null) throw new NullPointerException();
5429	>	return new SearchEntriesTask<K,V,U>
5430	>	(map, null, -1, searchFunction,
5431	>	new AtomicReference<U>());
5432	>	}
5433	>
5434	>	/**
5435	>	* Returns a task that when invoked, returns the result of
5436	>	* accumulating all entries using the given reducer to combine
5437	>	* values, or null if none.
5438	>	*
5439	>	* @param map the map
5440	>	* @param reducer a commutative associative combining function
5441	>	* @return the task
5442	>	*/
5443	>	public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
5444	>	(ConcurrentHashMap<K,V> map,
5445	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5446	>	if (reducer == null) throw new NullPointerException();
5447	>	return new ReduceEntriesTask<K,V>
5448	>	(map, null, -1, null, reducer);
5449	>	}
5450	>
5451	>	/**
5452	>	* Returns a task that when invoked, returns the result of
5453	>	* accumulating the given transformation of all entries using the
5454	>	* given reducer to combine values, or null if none.
5455	>	*
5456	>	* @param map the map
5457	>	* @param transformer a function returning the transformation
5458	>	* for an element, or null if there is no transformation (in
5459	>	* which case it is not combined)
5460	>	* @param reducer a commutative associative combining function
5461	>	* @return the task
5462	>	*/
5463	>	public static <K,V,U> ForkJoinTask<U> reduceEntries
5464	>	(ConcurrentHashMap<K,V> map,
5465	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5466	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5467	>	if (transformer == null || reducer == null)
5468	>	throw new NullPointerException();
5469	>	return new MapReduceEntriesTask<K,V,U>
5470	>	(map, null, -1, null, transformer, reducer);
5471	>	}
5472	>
5473	>	/**
5474	>	* Returns a task that when invoked, returns the result of
5475	>	* accumulating the given transformation of all entries using the
5476	>	* given reducer to combine values, and the given basis as an
5477	>	* identity value.
5478	>	*
5479	>	* @param map the map
5480	>	* @param transformer a function returning the transformation
5481	>	* for an element
5482	>	* @param basis the identity (initial default value) for the reduction
5483	>	* @param reducer a commutative associative combining function
5484	>	* @return the task
5485	>	*/
5486	>	public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
5487	>	(ConcurrentHashMap<K,V> map,
5488	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5489	>	double basis,
5490	>	DoubleBinaryOperator reducer) {
5491	>	if (transformer == null || reducer == null)
5492	>	throw new NullPointerException();
5493	>	return new MapReduceEntriesToDoubleTask<K,V>
5494	>	(map, null, -1, null, transformer, basis, reducer);
5495	>	}
5496	>
5497	>	/**
5498	>	* Returns a task that when invoked, returns the result of
5499	>	* accumulating the given transformation of all entries using the
5500	>	* given reducer to combine values, and the given basis as an
5501	>	* identity value.
5502	>	*
5503	>	* @param map the map
5504	>	* @param transformer a function returning the transformation
5505	>	* for an element
5506	>	* @param basis the identity (initial default value) for the reduction
5507	>	* @param reducer a commutative associative combining function
5508	>	* @return the task
5509	>	*/
5510	>	public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
5511	>	(ConcurrentHashMap<K,V> map,
5512	>	ToLongFunction<Map.Entry<K,V>> transformer,
5513	>	long basis,
5514	>	LongBinaryOperator reducer) {
5515	>	if (transformer == null || reducer == null)
5516	>	throw new NullPointerException();
5517	>	return new MapReduceEntriesToLongTask<K,V>
5518	>	(map, null, -1, null, transformer, basis, reducer);
5519	>	}
5520	>
5521	>	/**
5522	>	* Returns a task that when invoked, returns the result of
5523	>	* accumulating the given transformation of all entries using the
5524	>	* given reducer to combine values, and the given basis as an
5525	>	* identity value.
5526	>	*
5527	>	* @param map the map
5528	>	* @param transformer a function returning the transformation
5529	>	* for an element
5530	>	* @param basis the identity (initial default value) for the reduction
5531	>	* @param reducer a commutative associative combining function
5532	>	* @return the task
5533	>	*/
5534	>	public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
5535	>	(ConcurrentHashMap<K,V> map,
5536	>	ToIntFunction<Map.Entry<K,V>> transformer,
5537	>	int basis,
5538	>	IntBinaryOperator reducer) {
5539	>	if (transformer == null || reducer == null)
5540	>	throw new NullPointerException();
5541	>	return new MapReduceEntriesToIntTask<K,V>
5542	>	(map, null, -1, null, transformer, basis, reducer);
5543	>	}
5544	>	}
5545	>
5546	>	// -------------------------------------------------------
5547	>
5548	>	/*
5549	>	* Task classes. Coded in a regular but ugly format/style to
5550	>	* simplify checks that each variant differs in the right way from
5551	>	* others. The null screenings exist because compilers cannot tell
5552	>	* that we've already null-checked task arguments, so we force
5553	>	* simplest hoisted bypass to help avoid convoluted traps.
5554	>	*/
5555	>
5556	>	@SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
5557	>	extends Traverser<K,V,Void> {
5558	>	final Consumer<? super K> action;
5559	>	ForEachKeyTask
5560	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5561	>	Consumer<? super K> action) {
5562	>	super(m, p, b);
5563	>	this.action = action;
5564	>	}
5565	>	public final void compute() {
5566	>	final Consumer<? super K> action;
5567	>	if ((action = this.action) != null) {
5568	>	for (int b; (b = preSplit()) > 0;)
5569	>	new ForEachKeyTask<K,V>(map, this, b, action).fork();
5570	>	while (advance() != null)
5571	>	action.accept(nextKey);
5572	>	propagateCompletion();
5573		}
5574		}
5575	+	}
5576
5577	<	// Read the keys and values, and put the mappings in the table
5578	<	for (;;) {
5579	<	K key = (K) s.readObject();
5580	<	V value = (V) s.readObject();
5581	<	if (key == null)
5582	<	break;
5583	<	put(key, value);
5577	>	@SuppressWarnings("serial") static final class ForEachValueTask<K,V>
5578	>	extends Traverser<K,V,Void> {
5579	>	final Consumer<? super V> action;
5580	>	ForEachValueTask
5581	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5582	>	Consumer<? super V> action) {
5583	>	super(m, p, b);
5584	>	this.action = action;
5585	>	}
5586	>	public final void compute() {
5587	>	final Consumer<? super V> action;
5588	>	if ((action = this.action) != null) {
5589	>	for (int b; (b = preSplit()) > 0;)
5590	>	new ForEachValueTask<K,V>(map, this, b, action).fork();
5591	>	V v;
5592	>	while ((v = advance()) != null)
5593	>	action.accept(v);
5594	>	propagateCompletion();
5595	>	}
5596	>	}
5597	>	}
5598	>
5599	>	@SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5600	>	extends Traverser<K,V,Void> {
5601	>	final Consumer<? super Entry<K,V>> action;
5602	>	ForEachEntryTask
5603	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5604	>	Consumer<? super Entry<K,V>> action) {
5605	>	super(m, p, b);
5606	>	this.action = action;
5607	>	}
5608	>	public final void compute() {
5609	>	final Consumer<? super Entry<K,V>> action;
5610	>	if ((action = this.action) != null) {
5611	>	for (int b; (b = preSplit()) > 0;)
5612	>	new ForEachEntryTask<K,V>(map, this, b, action).fork();
5613	>	V v;
5614	>	while ((v = advance()) != null)
5615	>	action.accept(entryFor(nextKey, v));
5616	>	propagateCompletion();
5617	>	}
5618	>	}
5619	>	}
5620	>
5621	>	@SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5622	>	extends Traverser<K,V,Void> {
5623	>	final BiConsumer<? super K, ? super V> action;
5624	>	ForEachMappingTask
5625	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5626	>	BiConsumer<? super K,? super V> action) {
5627	>	super(m, p, b);
5628	>	this.action = action;
5629	>	}
5630	>	public final void compute() {
5631	>	final BiConsumer<? super K, ? super V> action;
5632	>	if ((action = this.action) != null) {
5633	>	for (int b; (b = preSplit()) > 0;)
5634	>	new ForEachMappingTask<K,V>(map, this, b, action).fork();
5635	>	V v;
5636	>	while ((v = advance()) != null)
5637	>	action.accept(nextKey, v);
5638	>	propagateCompletion();
5639	>	}
5640	>	}
5641	>	}
5642	>
5643	>	@SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5644	>	extends Traverser<K,V,Void> {
5645	>	final Function<? super K, ? extends U> transformer;
5646	>	final Consumer<? super U> action;
5647	>	ForEachTransformedKeyTask
5648	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5649	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5650	>	super(m, p, b);
5651	>	this.transformer = transformer; this.action = action;
5652	>	}
5653	>	public final void compute() {
5654	>	final Function<? super K, ? extends U> transformer;
5655	>	final Consumer<? super U> action;
5656	>	if ((transformer = this.transformer) != null &&
5657	>	(action = this.action) != null) {
5658	>	for (int b; (b = preSplit()) > 0;)
5659	>	new ForEachTransformedKeyTask<K,V,U>
5660	>	(map, this, b, transformer, action).fork();
5661	>	U u;
5662	>	while (advance() != null) {
5663	>	if ((u = transformer.apply(nextKey)) != null)
5664	>	action.accept(u);
5665	>	}
5666	>	propagateCompletion();
5667	>	}
5668	>	}
5669	>	}
5670	>
5671	>	@SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5672	>	extends Traverser<K,V,Void> {
5673	>	final Function<? super V, ? extends U> transformer;
5674	>	final Consumer<? super U> action;
5675	>	ForEachTransformedValueTask
5676	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5677	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5678	>	super(m, p, b);
5679	>	this.transformer = transformer; this.action = action;
5680	>	}
5681	>	public final void compute() {
5682	>	final Function<? super V, ? extends U> transformer;
5683	>	final Consumer<? super U> action;
5684	>	if ((transformer = this.transformer) != null &&
5685	>	(action = this.action) != null) {
5686	>	for (int b; (b = preSplit()) > 0;)
5687	>	new ForEachTransformedValueTask<K,V,U>
5688	>	(map, this, b, transformer, action).fork();
5689	>	V v; U u;
5690	>	while ((v = advance()) != null) {
5691	>	if ((u = transformer.apply(v)) != null)
5692	>	action.accept(u);
5693	>	}
5694	>	propagateCompletion();
5695	>	}
5696	>	}
5697	>	}
5698	>
5699	>	@SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5700	>	extends Traverser<K,V,Void> {
5701	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5702	>	final Consumer<? super U> action;
5703	>	ForEachTransformedEntryTask
5704	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5705	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5706	>	super(m, p, b);
5707	>	this.transformer = transformer; this.action = action;
5708	>	}
5709	>	public final void compute() {
5710	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5711	>	final Consumer<? super U> action;
5712	>	if ((transformer = this.transformer) != null &&
5713	>	(action = this.action) != null) {
5714	>	for (int b; (b = preSplit()) > 0;)
5715	>	new ForEachTransformedEntryTask<K,V,U>
5716	>	(map, this, b, transformer, action).fork();
5717	>	V v; U u;
5718	>	while ((v = advance()) != null) {
5719	>	if ((u = transformer.apply(entryFor(nextKey,
5720	>	v))) != null)
5721	>	action.accept(u);
5722	>	}
5723	>	propagateCompletion();
5724	>	}
5725	>	}
5726	>	}
5727	>
5728	>	@SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5729	>	extends Traverser<K,V,Void> {
5730	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5731	>	final Consumer<? super U> action;
5732	>	ForEachTransformedMappingTask
5733	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5734	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5735	>	Consumer<? super U> action) {
5736	>	super(m, p, b);
5737	>	this.transformer = transformer; this.action = action;
5738	>	}
5739	>	public final void compute() {
5740	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5741	>	final Consumer<? super U> action;
5742	>	if ((transformer = this.transformer) != null &&
5743	>	(action = this.action) != null) {
5744	>	for (int b; (b = preSplit()) > 0;)
5745	>	new ForEachTransformedMappingTask<K,V,U>
5746	>	(map, this, b, transformer, action).fork();
5747	>	V v; U u;
5748	>	while ((v = advance()) != null) {
5749	>	if ((u = transformer.apply(nextKey, v)) != null)
5750	>	action.accept(u);
5751	>	}
5752	>	propagateCompletion();
5753	>	}
5754	>	}
5755	>	}
5756	>
5757	>	@SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5758	>	extends Traverser<K,V,U> {
5759	>	final Function<? super K, ? extends U> searchFunction;
5760	>	final AtomicReference<U> result;
5761	>	SearchKeysTask
5762	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5763	>	Function<? super K, ? extends U> searchFunction,
5764	>	AtomicReference<U> result) {
5765	>	super(m, p, b);
5766	>	this.searchFunction = searchFunction; this.result = result;
5767	>	}
5768	>	public final U getRawResult() { return result.get(); }
5769	>	public final void compute() {
5770	>	final Function<? super K, ? extends U> searchFunction;
5771	>	final AtomicReference<U> result;
5772	>	if ((searchFunction = this.searchFunction) != null &&
5773	>	(result = this.result) != null) {
5774	>	for (int b;;) {
5775	>	if (result.get() != null)
5776	>	return;
5777	>	if ((b = preSplit()) <= 0)
5778	>	break;
5779	>	new SearchKeysTask<K,V,U>
5780	>	(map, this, b, searchFunction, result).fork();
5781	>	}
5782	>	while (result.get() == null) {
5783	>	U u;
5784	>	if (advance() == null) {
5785	>	propagateCompletion();
5786	>	break;
5787	>	}
5788	>	if ((u = searchFunction.apply(nextKey)) != null) {
5789	>	if (result.compareAndSet(null, u))
5790	>	quietlyCompleteRoot();
5791	>	break;
5792	>	}
5793	>	}
5794	>	}
5795	>	}
5796	>	}
5797	>
5798	>	@SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5799	>	extends Traverser<K,V,U> {
5800	>	final Function<? super V, ? extends U> searchFunction;
5801	>	final AtomicReference<U> result;
5802	>	SearchValuesTask
5803	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5804	>	Function<? super V, ? extends U> searchFunction,
5805	>	AtomicReference<U> result) {
5806	>	super(m, p, b);
5807	>	this.searchFunction = searchFunction; this.result = result;
5808	>	}
5809	>	public final U getRawResult() { return result.get(); }
5810	>	public final void compute() {
5811	>	final Function<? super V, ? extends U> searchFunction;
5812	>	final AtomicReference<U> result;
5813	>	if ((searchFunction = this.searchFunction) != null &&
5814	>	(result = this.result) != null) {
5815	>	for (int b;;) {
5816	>	if (result.get() != null)
5817	>	return;
5818	>	if ((b = preSplit()) <= 0)
5819	>	break;
5820	>	new SearchValuesTask<K,V,U>
5821	>	(map, this, b, searchFunction, result).fork();
5822	>	}
5823	>	while (result.get() == null) {
5824	>	V v; U u;
5825	>	if ((v = advance()) == null) {
5826	>	propagateCompletion();
5827	>	break;
5828	>	}
5829	>	if ((u = searchFunction.apply(v)) != null) {
5830	>	if (result.compareAndSet(null, u))
5831	>	quietlyCompleteRoot();
5832	>	break;
5833	>	}
5834	>	}
5835	>	}
5836	>	}
5837	>	}
5838	>
5839	>	@SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5840	>	extends Traverser<K,V,U> {
5841	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5842	>	final AtomicReference<U> result;
5843	>	SearchEntriesTask
5844	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5845	>	Function<Entry<K,V>, ? extends U> searchFunction,
5846	>	AtomicReference<U> result) {
5847	>	super(m, p, b);
5848	>	this.searchFunction = searchFunction; this.result = result;
5849	>	}
5850	>	public final U getRawResult() { return result.get(); }
5851	>	public final void compute() {
5852	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5853	>	final AtomicReference<U> result;
5854	>	if ((searchFunction = this.searchFunction) != null &&
5855	>	(result = this.result) != null) {
5856	>	for (int b;;) {
5857	>	if (result.get() != null)
5858	>	return;
5859	>	if ((b = preSplit()) <= 0)
5860	>	break;
5861	>	new SearchEntriesTask<K,V,U>
5862	>	(map, this, b, searchFunction, result).fork();
5863	>	}
5864	>	while (result.get() == null) {
5865	>	V v; U u;
5866	>	if ((v = advance()) == null) {
5867	>	propagateCompletion();
5868	>	break;
5869	>	}
5870	>	if ((u = searchFunction.apply(entryFor(nextKey,
5871	>	v))) != null) {
5872	>	if (result.compareAndSet(null, u))
5873	>	quietlyCompleteRoot();
5874	>	return;
5875	>	}
5876	>	}
5877	>	}
5878	>	}
5879	>	}
5880	>
5881	>	@SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5882	>	extends Traverser<K,V,U> {
5883	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5884	>	final AtomicReference<U> result;
5885	>	SearchMappingsTask
5886	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5887	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5888	>	AtomicReference<U> result) {
5889	>	super(m, p, b);
5890	>	this.searchFunction = searchFunction; this.result = result;
5891	>	}
5892	>	public final U getRawResult() { return result.get(); }
5893	>	public final void compute() {
5894	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5895	>	final AtomicReference<U> result;
5896	>	if ((searchFunction = this.searchFunction) != null &&
5897	>	(result = this.result) != null) {
5898	>	for (int b;;) {
5899	>	if (result.get() != null)
5900	>	return;
5901	>	if ((b = preSplit()) <= 0)
5902	>	break;
5903	>	new SearchMappingsTask<K,V,U>
5904	>	(map, this, b, searchFunction, result).fork();
5905	>	}
5906	>	while (result.get() == null) {
5907	>	V v; U u;
5908	>	if ((v = advance()) == null) {
5909	>	propagateCompletion();
5910	>	break;
5911	>	}
5912	>	if ((u = searchFunction.apply(nextKey, v)) != null) {
5913	>	if (result.compareAndSet(null, u))
5914	>	quietlyCompleteRoot();
5915	>	break;
5916	>	}
5917	>	}
5918	>	}
5919	>	}
5920	>	}
5921	>
5922	>	@SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5923	>	extends Traverser<K,V,K> {
5924	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5925	>	K result;
5926	>	ReduceKeysTask<K,V> rights, nextRight;
5927	>	ReduceKeysTask
5928	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5929	>	ReduceKeysTask<K,V> nextRight,
5930	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5931	>	super(m, p, b); this.nextRight = nextRight;
5932	>	this.reducer = reducer;
5933	>	}
5934	>	public final K getRawResult() { return result; }
5935	>	@SuppressWarnings("unchecked") public final void compute() {
5936	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5937	>	if ((reducer = this.reducer) != null) {
5938	>	for (int b; (b = preSplit()) > 0;)
5939	>	(rights = new ReduceKeysTask<K,V>
5940	>	(map, this, b, rights, reducer)).fork();
5941	>	K r = null;
5942	>	while (advance() != null) {
5943	>	K u = nextKey;
5944	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5945	>	}
5946	>	result = r;
5947	>	CountedCompleter<?> c;
5948	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5949	>	ReduceKeysTask<K,V>
5950	>	t = (ReduceKeysTask<K,V>)c,
5951	>	s = t.rights;
5952	>	while (s != null) {
5953	>	K tr, sr;
5954	>	if ((sr = s.result) != null)
5955	>	t.result = (((tr = t.result) == null) ? sr :
5956	>	reducer.apply(tr, sr));
5957	>	s = t.rights = s.nextRight;
5958	>	}
5959	>	}
5960	>	}
5961	>	}
5962	>	}
5963	>
5964	>	@SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5965	>	extends Traverser<K,V,V> {
5966	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5967	>	V result;
5968	>	ReduceValuesTask<K,V> rights, nextRight;
5969	>	ReduceValuesTask
5970	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5971	>	ReduceValuesTask<K,V> nextRight,
5972	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5973	>	super(m, p, b); this.nextRight = nextRight;
5974	>	this.reducer = reducer;
5975	>	}
5976	>	public final V getRawResult() { return result; }
5977	>	@SuppressWarnings("unchecked") public final void compute() {
5978	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5979	>	if ((reducer = this.reducer) != null) {
5980	>	for (int b; (b = preSplit()) > 0;)
5981	>	(rights = new ReduceValuesTask<K,V>
5982	>	(map, this, b, rights, reducer)).fork();
5983	>	V r = null, v;
5984	>	while ((v = advance()) != null)
5985	>	r = (r == null) ? v : reducer.apply(r, v);
5986	>	result = r;
5987	>	CountedCompleter<?> c;
5988	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5989	>	ReduceValuesTask<K,V>
5990	>	t = (ReduceValuesTask<K,V>)c,
5991	>	s = t.rights;
5992	>	while (s != null) {
5993	>	V tr, sr;
5994	>	if ((sr = s.result) != null)
5995	>	t.result = (((tr = t.result) == null) ? sr :
5996	>	reducer.apply(tr, sr));
5997	>	s = t.rights = s.nextRight;
5998	>	}
5999	>	}
6000	>	}
6001	>	}
6002	>	}
6003	>
6004	>	@SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
6005	>	extends Traverser<K,V,Map.Entry<K,V>> {
6006	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
6007	>	Map.Entry<K,V> result;
6008	>	ReduceEntriesTask<K,V> rights, nextRight;
6009	>	ReduceEntriesTask
6010	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6011	>	ReduceEntriesTask<K,V> nextRight,
6012	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
6013	>	super(m, p, b); this.nextRight = nextRight;
6014	>	this.reducer = reducer;
6015	>	}
6016	>	public final Map.Entry<K,V> getRawResult() { return result; }
6017	>	@SuppressWarnings("unchecked") public final void compute() {
6018	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
6019	>	if ((reducer = this.reducer) != null) {
6020	>	for (int b; (b = preSplit()) > 0;)
6021	>	(rights = new ReduceEntriesTask<K,V>
6022	>	(map, this, b, rights, reducer)).fork();
6023	>	Map.Entry<K,V> r = null;
6024	>	V v;
6025	>	while ((v = advance()) != null) {
6026	>	Map.Entry<K,V> u = entryFor(nextKey, v);
6027	>	r = (r == null) ? u : reducer.apply(r, u);
6028	>	}
6029	>	result = r;
6030	>	CountedCompleter<?> c;
6031	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6032	>	ReduceEntriesTask<K,V>
6033	>	t = (ReduceEntriesTask<K,V>)c,
6034	>	s = t.rights;
6035	>	while (s != null) {
6036	>	Map.Entry<K,V> tr, sr;
6037	>	if ((sr = s.result) != null)
6038	>	t.result = (((tr = t.result) == null) ? sr :
6039	>	reducer.apply(tr, sr));
6040	>	s = t.rights = s.nextRight;
6041	>	}
6042	>	}
6043	>	}
6044	>	}
6045	>	}
6046	>
6047	>	@SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
6048	>	extends Traverser<K,V,U> {
6049	>	final Function<? super K, ? extends U> transformer;
6050	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6051	>	U result;
6052	>	MapReduceKeysTask<K,V,U> rights, nextRight;
6053	>	MapReduceKeysTask
6054	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6055	>	MapReduceKeysTask<K,V,U> nextRight,
6056	>	Function<? super K, ? extends U> transformer,
6057	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6058	>	super(m, p, b); this.nextRight = nextRight;
6059	>	this.transformer = transformer;
6060	>	this.reducer = reducer;
6061	>	}
6062	>	public final U getRawResult() { return result; }
6063	>	@SuppressWarnings("unchecked") public final void compute() {
6064	>	final Function<? super K, ? extends U> transformer;
6065	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6066	>	if ((transformer = this.transformer) != null &&
6067	>	(reducer = this.reducer) != null) {
6068	>	for (int b; (b = preSplit()) > 0;)
6069	>	(rights = new MapReduceKeysTask<K,V,U>
6070	>	(map, this, b, rights, transformer, reducer)).fork();
6071	>	U r = null, u;
6072	>	while (advance() != null) {
6073	>	if ((u = transformer.apply(nextKey)) != null)
6074	>	r = (r == null) ? u : reducer.apply(r, u);
6075	>	}
6076	>	result = r;
6077	>	CountedCompleter<?> c;
6078	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6079	>	MapReduceKeysTask<K,V,U>
6080	>	t = (MapReduceKeysTask<K,V,U>)c,
6081	>	s = t.rights;
6082	>	while (s != null) {
6083	>	U tr, sr;
6084	>	if ((sr = s.result) != null)
6085	>	t.result = (((tr = t.result) == null) ? sr :
6086	>	reducer.apply(tr, sr));
6087	>	s = t.rights = s.nextRight;
6088	>	}
6089	>	}
6090	>	}
6091	>	}
6092	>	}
6093	>
6094	>	@SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
6095	>	extends Traverser<K,V,U> {
6096	>	final Function<? super V, ? extends U> transformer;
6097	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6098	>	U result;
6099	>	MapReduceValuesTask<K,V,U> rights, nextRight;
6100	>	MapReduceValuesTask
6101	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6102	>	MapReduceValuesTask<K,V,U> nextRight,
6103	>	Function<? super V, ? extends U> transformer,
6104	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6105	>	super(m, p, b); this.nextRight = nextRight;
6106	>	this.transformer = transformer;
6107	>	this.reducer = reducer;
6108	>	}
6109	>	public final U getRawResult() { return result; }
6110	>	@SuppressWarnings("unchecked") public final void compute() {
6111	>	final Function<? super V, ? extends U> transformer;
6112	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6113	>	if ((transformer = this.transformer) != null &&
6114	>	(reducer = this.reducer) != null) {
6115	>	for (int b; (b = preSplit()) > 0;)
6116	>	(rights = new MapReduceValuesTask<K,V,U>
6117	>	(map, this, b, rights, transformer, reducer)).fork();
6118	>	U r = null, u;
6119	>	V v;
6120	>	while ((v = advance()) != null) {
6121	>	if ((u = transformer.apply(v)) != null)
6122	>	r = (r == null) ? u : reducer.apply(r, u);
6123	>	}
6124	>	result = r;
6125	>	CountedCompleter<?> c;
6126	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6127	>	MapReduceValuesTask<K,V,U>
6128	>	t = (MapReduceValuesTask<K,V,U>)c,
6129	>	s = t.rights;
6130	>	while (s != null) {
6131	>	U tr, sr;
6132	>	if ((sr = s.result) != null)
6133	>	t.result = (((tr = t.result) == null) ? sr :
6134	>	reducer.apply(tr, sr));
6135	>	s = t.rights = s.nextRight;
6136	>	}
6137	>	}
6138	>	}
6139	>	}
6140	>	}
6141	>
6142	>	@SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
6143	>	extends Traverser<K,V,U> {
6144	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
6145	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6146	>	U result;
6147	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
6148	>	MapReduceEntriesTask
6149	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6150	>	MapReduceEntriesTask<K,V,U> nextRight,
6151	>	Function<Map.Entry<K,V>, ? extends U> transformer,
6152	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6153	>	super(m, p, b); this.nextRight = nextRight;
6154	>	this.transformer = transformer;
6155	>	this.reducer = reducer;
6156	>	}
6157	>	public final U getRawResult() { return result; }
6158	>	@SuppressWarnings("unchecked") public final void compute() {
6159	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
6160	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6161	>	if ((transformer = this.transformer) != null &&
6162	>	(reducer = this.reducer) != null) {
6163	>	for (int b; (b = preSplit()) > 0;)
6164	>	(rights = new MapReduceEntriesTask<K,V,U>
6165	>	(map, this, b, rights, transformer, reducer)).fork();
6166	>	U r = null, u;
6167	>	V v;
6168	>	while ((v = advance()) != null) {
6169	>	if ((u = transformer.apply(entryFor(nextKey,
6170	>	v))) != null)
6171	>	r = (r == null) ? u : reducer.apply(r, u);
6172	>	}
6173	>	result = r;
6174	>	CountedCompleter<?> c;
6175	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6176	>	MapReduceEntriesTask<K,V,U>
6177	>	t = (MapReduceEntriesTask<K,V,U>)c,
6178	>	s = t.rights;
6179	>	while (s != null) {
6180	>	U tr, sr;
6181	>	if ((sr = s.result) != null)
6182	>	t.result = (((tr = t.result) == null) ? sr :
6183	>	reducer.apply(tr, sr));
6184	>	s = t.rights = s.nextRight;
6185	>	}
6186	>	}
6187	>	}
6188	>	}
6189	>	}
6190	>
6191	>	@SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
6192	>	extends Traverser<K,V,U> {
6193	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
6194	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6195	>	U result;
6196	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
6197	>	MapReduceMappingsTask
6198	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6199	>	MapReduceMappingsTask<K,V,U> nextRight,
6200	>	BiFunction<? super K, ? super V, ? extends U> transformer,
6201	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6202	>	super(m, p, b); this.nextRight = nextRight;
6203	>	this.transformer = transformer;
6204	>	this.reducer = reducer;
6205	>	}
6206	>	public final U getRawResult() { return result; }
6207	>	@SuppressWarnings("unchecked") public final void compute() {
6208	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
6209	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6210	>	if ((transformer = this.transformer) != null &&
6211	>	(reducer = this.reducer) != null) {
6212	>	for (int b; (b = preSplit()) > 0;)
6213	>	(rights = new MapReduceMappingsTask<K,V,U>
6214	>	(map, this, b, rights, transformer, reducer)).fork();
6215	>	U r = null, u;
6216	>	V v;
6217	>	while ((v = advance()) != null) {
6218	>	if ((u = transformer.apply(nextKey, v)) != null)
6219	>	r = (r == null) ? u : reducer.apply(r, u);
6220	>	}
6221	>	result = r;
6222	>	CountedCompleter<?> c;
6223	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6224	>	MapReduceMappingsTask<K,V,U>
6225	>	t = (MapReduceMappingsTask<K,V,U>)c,
6226	>	s = t.rights;
6227	>	while (s != null) {
6228	>	U tr, sr;
6229	>	if ((sr = s.result) != null)
6230	>	t.result = (((tr = t.result) == null) ? sr :
6231	>	reducer.apply(tr, sr));
6232	>	s = t.rights = s.nextRight;
6233	>	}
6234	>	}
6235	>	}
6236	>	}
6237	>	}
6238	>
6239	>	@SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
6240	>	extends Traverser<K,V,Double> {
6241	>	final ToDoubleFunction<? super K> transformer;
6242	>	final DoubleBinaryOperator reducer;
6243	>	final double basis;
6244	>	double result;
6245	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
6246	>	MapReduceKeysToDoubleTask
6247	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6248	>	MapReduceKeysToDoubleTask<K,V> nextRight,
6249	>	ToDoubleFunction<? super K> transformer,
6250	>	double basis,
6251	>	DoubleBinaryOperator reducer) {
6252	>	super(m, p, b); this.nextRight = nextRight;
6253	>	this.transformer = transformer;
6254	>	this.basis = basis; this.reducer = reducer;
6255	>	}
6256	>	public final Double getRawResult() { return result; }
6257	>	@SuppressWarnings("unchecked") public final void compute() {
6258	>	final ToDoubleFunction<? super K> transformer;
6259	>	final DoubleBinaryOperator reducer;
6260	>	if ((transformer = this.transformer) != null &&
6261	>	(reducer = this.reducer) != null) {
6262	>	double r = this.basis;
6263	>	for (int b; (b = preSplit()) > 0;)
6264	>	(rights = new MapReduceKeysToDoubleTask<K,V>
6265	>	(map, this, b, rights, transformer, r, reducer)).fork();
6266	>	while (advance() != null)
6267	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(nextKey));
6268	>	result = r;
6269	>	CountedCompleter<?> c;
6270	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6271	>	MapReduceKeysToDoubleTask<K,V>
6272	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
6273	>	s = t.rights;
6274	>	while (s != null) {
6275	>	t.result = reducer.applyAsDouble(t.result, s.result);
6276	>	s = t.rights = s.nextRight;
6277	>	}
6278	>	}
6279	>	}
6280	>	}
6281	>	}
6282	>
6283	>	@SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
6284	>	extends Traverser<K,V,Double> {
6285	>	final ToDoubleFunction<? super V> transformer;
6286	>	final DoubleBinaryOperator reducer;
6287	>	final double basis;
6288	>	double result;
6289	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
6290	>	MapReduceValuesToDoubleTask
6291	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6292	>	MapReduceValuesToDoubleTask<K,V> nextRight,
6293	>	ToDoubleFunction<? super V> transformer,
6294	>	double basis,
6295	>	DoubleBinaryOperator reducer) {
6296	>	super(m, p, b); this.nextRight = nextRight;
6297	>	this.transformer = transformer;
6298	>	this.basis = basis; this.reducer = reducer;
6299	>	}
6300	>	public final Double getRawResult() { return result; }
6301	>	@SuppressWarnings("unchecked") public final void compute() {
6302	>	final ToDoubleFunction<? super V> transformer;
6303	>	final DoubleBinaryOperator reducer;
6304	>	if ((transformer = this.transformer) != null &&
6305	>	(reducer = this.reducer) != null) {
6306	>	double r = this.basis;
6307	>	for (int b; (b = preSplit()) > 0;)
6308	>	(rights = new MapReduceValuesToDoubleTask<K,V>
6309	>	(map, this, b, rights, transformer, r, reducer)).fork();
6310	>	V v;
6311	>	while ((v = advance()) != null)
6312	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
6313	>	result = r;
6314	>	CountedCompleter<?> c;
6315	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6316	>	MapReduceValuesToDoubleTask<K,V>
6317	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
6318	>	s = t.rights;
6319	>	while (s != null) {
6320	>	t.result = reducer.applyAsDouble(t.result, s.result);
6321	>	s = t.rights = s.nextRight;
6322	>	}
6323	>	}
6324	>	}
6325	>	}
6326	>	}
6327	>
6328	>	@SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6329	>	extends Traverser<K,V,Double> {
6330	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
6331	>	final DoubleBinaryOperator reducer;
6332	>	final double basis;
6333	>	double result;
6334	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6335	>	MapReduceEntriesToDoubleTask
6336	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6337	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
6338	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
6339	>	double basis,
6340	>	DoubleBinaryOperator reducer) {
6341	>	super(m, p, b); this.nextRight = nextRight;
6342	>	this.transformer = transformer;
6343	>	this.basis = basis; this.reducer = reducer;
6344	>	}
6345	>	public final Double getRawResult() { return result; }
6346	>	@SuppressWarnings("unchecked") public final void compute() {
6347	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
6348	>	final DoubleBinaryOperator reducer;
6349	>	if ((transformer = this.transformer) != null &&
6350	>	(reducer = this.reducer) != null) {
6351	>	double r = this.basis;
6352	>	for (int b; (b = preSplit()) > 0;)
6353	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
6354	>	(map, this, b, rights, transformer, r, reducer)).fork();
6355	>	V v;
6356	>	while ((v = advance()) != null)
6357	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor(nextKey,
6358	>	v)));
6359	>	result = r;
6360	>	CountedCompleter<?> c;
6361	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6362	>	MapReduceEntriesToDoubleTask<K,V>
6363	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
6364	>	s = t.rights;
6365	>	while (s != null) {
6366	>	t.result = reducer.applyAsDouble(t.result, s.result);
6367	>	s = t.rights = s.nextRight;
6368	>	}
6369	>	}
6370	>	}
6371	>	}
6372	>	}
6373	>
6374	>	@SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6375	>	extends Traverser<K,V,Double> {
6376	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
6377	>	final DoubleBinaryOperator reducer;
6378	>	final double basis;
6379	>	double result;
6380	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6381	>	MapReduceMappingsToDoubleTask
6382	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6383	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
6384	>	ToDoubleBiFunction<? super K, ? super V> transformer,
6385	>	double basis,
6386	>	DoubleBinaryOperator reducer) {
6387	>	super(m, p, b); this.nextRight = nextRight;
6388	>	this.transformer = transformer;
6389	>	this.basis = basis; this.reducer = reducer;
6390	>	}
6391	>	public final Double getRawResult() { return result; }
6392	>	@SuppressWarnings("unchecked") public final void compute() {
6393	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
6394	>	final DoubleBinaryOperator reducer;
6395	>	if ((transformer = this.transformer) != null &&
6396	>	(reducer = this.reducer) != null) {
6397	>	double r = this.basis;
6398	>	for (int b; (b = preSplit()) > 0;)
6399	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
6400	>	(map, this, b, rights, transformer, r, reducer)).fork();
6401	>	V v;
6402	>	while ((v = advance()) != null)
6403	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(nextKey, v));
6404	>	result = r;
6405	>	CountedCompleter<?> c;
6406	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6407	>	MapReduceMappingsToDoubleTask<K,V>
6408	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
6409	>	s = t.rights;
6410	>	while (s != null) {
6411	>	t.result = reducer.applyAsDouble(t.result, s.result);
6412	>	s = t.rights = s.nextRight;
6413	>	}
6414	>	}
6415	>	}
6416	>	}
6417	>	}
6418	>
6419	>	@SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6420	>	extends Traverser<K,V,Long> {
6421	>	final ToLongFunction<? super K> transformer;
6422	>	final LongBinaryOperator reducer;
6423	>	final long basis;
6424	>	long result;
6425	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
6426	>	MapReduceKeysToLongTask
6427	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6428	>	MapReduceKeysToLongTask<K,V> nextRight,
6429	>	ToLongFunction<? super K> transformer,
6430	>	long basis,
6431	>	LongBinaryOperator reducer) {
6432	>	super(m, p, b); this.nextRight = nextRight;
6433	>	this.transformer = transformer;
6434	>	this.basis = basis; this.reducer = reducer;
6435	>	}
6436	>	public final Long getRawResult() { return result; }
6437	>	@SuppressWarnings("unchecked") public final void compute() {
6438	>	final ToLongFunction<? super K> transformer;
6439	>	final LongBinaryOperator reducer;
6440	>	if ((transformer = this.transformer) != null &&
6441	>	(reducer = this.reducer) != null) {
6442	>	long r = this.basis;
6443	>	for (int b; (b = preSplit()) > 0;)
6444	>	(rights = new MapReduceKeysToLongTask<K,V>
6445	>	(map, this, b, rights, transformer, r, reducer)).fork();
6446	>	while (advance() != null)
6447	>	r = reducer.applyAsLong(r, transformer.applyAsLong(nextKey));
6448	>	result = r;
6449	>	CountedCompleter<?> c;
6450	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6451	>	MapReduceKeysToLongTask<K,V>
6452	>	t = (MapReduceKeysToLongTask<K,V>)c,
6453	>	s = t.rights;
6454	>	while (s != null) {
6455	>	t.result = reducer.applyAsLong(t.result, s.result);
6456	>	s = t.rights = s.nextRight;
6457	>	}
6458	>	}
6459	>	}
6460	>	}
6461	>	}
6462	>
6463	>	@SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6464	>	extends Traverser<K,V,Long> {
6465	>	final ToLongFunction<? super V> transformer;
6466	>	final LongBinaryOperator reducer;
6467	>	final long basis;
6468	>	long result;
6469	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
6470	>	MapReduceValuesToLongTask
6471	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6472	>	MapReduceValuesToLongTask<K,V> nextRight,
6473	>	ToLongFunction<? super V> transformer,
6474	>	long basis,
6475	>	LongBinaryOperator reducer) {
6476	>	super(m, p, b); this.nextRight = nextRight;
6477	>	this.transformer = transformer;
6478	>	this.basis = basis; this.reducer = reducer;
6479	>	}
6480	>	public final Long getRawResult() { return result; }
6481	>	@SuppressWarnings("unchecked") public final void compute() {
6482	>	final ToLongFunction<? super V> transformer;
6483	>	final LongBinaryOperator reducer;
6484	>	if ((transformer = this.transformer) != null &&
6485	>	(reducer = this.reducer) != null) {
6486	>	long r = this.basis;
6487	>	for (int b; (b = preSplit()) > 0;)
6488	>	(rights = new MapReduceValuesToLongTask<K,V>
6489	>	(map, this, b, rights, transformer, r, reducer)).fork();
6490	>	V v;
6491	>	while ((v = advance()) != null)
6492	>	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
6493	>	result = r;
6494	>	CountedCompleter<?> c;
6495	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6496	>	MapReduceValuesToLongTask<K,V>
6497	>	t = (MapReduceValuesToLongTask<K,V>)c,
6498	>	s = t.rights;
6499	>	while (s != null) {
6500	>	t.result = reducer.applyAsLong(t.result, s.result);
6501	>	s = t.rights = s.nextRight;
6502	>	}
6503	>	}
6504	>	}
6505	>	}
6506	>	}
6507	>
6508	>	@SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6509	>	extends Traverser<K,V,Long> {
6510	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6511	>	final LongBinaryOperator reducer;
6512	>	final long basis;
6513	>	long result;
6514	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6515	>	MapReduceEntriesToLongTask
6516	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6517	>	MapReduceEntriesToLongTask<K,V> nextRight,
6518	>	ToLongFunction<Map.Entry<K,V>> transformer,
6519	>	long basis,
6520	>	LongBinaryOperator reducer) {
6521	>	super(m, p, b); this.nextRight = nextRight;
6522	>	this.transformer = transformer;
6523	>	this.basis = basis; this.reducer = reducer;
6524	>	}
6525	>	public final Long getRawResult() { return result; }
6526	>	@SuppressWarnings("unchecked") public final void compute() {
6527	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6528	>	final LongBinaryOperator reducer;
6529	>	if ((transformer = this.transformer) != null &&
6530	>	(reducer = this.reducer) != null) {
6531	>	long r = this.basis;
6532	>	for (int b; (b = preSplit()) > 0;)
6533	>	(rights = new MapReduceEntriesToLongTask<K,V>
6534	>	(map, this, b, rights, transformer, r, reducer)).fork();
6535	>	V v;
6536	>	while ((v = advance()) != null)
6537	>	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor(nextKey, v)));
6538	>	result = r;
6539	>	CountedCompleter<?> c;
6540	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6541	>	MapReduceEntriesToLongTask<K,V>
6542	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6543	>	s = t.rights;
6544	>	while (s != null) {
6545	>	t.result = reducer.applyAsLong(t.result, s.result);
6546	>	s = t.rights = s.nextRight;
6547	>	}
6548	>	}
6549	>	}
6550	>	}
6551	>	}
6552	>
6553	>	@SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6554	>	extends Traverser<K,V,Long> {
6555	>	final ToLongBiFunction<? super K, ? super V> transformer;
6556	>	final LongBinaryOperator reducer;
6557	>	final long basis;
6558	>	long result;
6559	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6560	>	MapReduceMappingsToLongTask
6561	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6562	>	MapReduceMappingsToLongTask<K,V> nextRight,
6563	>	ToLongBiFunction<? super K, ? super V> transformer,
6564	>	long basis,
6565	>	LongBinaryOperator reducer) {
6566	>	super(m, p, b); this.nextRight = nextRight;
6567	>	this.transformer = transformer;
6568	>	this.basis = basis; this.reducer = reducer;
6569	>	}
6570	>	public final Long getRawResult() { return result; }
6571	>	@SuppressWarnings("unchecked") public final void compute() {
6572	>	final ToLongBiFunction<? super K, ? super V> transformer;
6573	>	final LongBinaryOperator reducer;
6574	>	if ((transformer = this.transformer) != null &&
6575	>	(reducer = this.reducer) != null) {
6576	>	long r = this.basis;
6577	>	for (int b; (b = preSplit()) > 0;)
6578	>	(rights = new MapReduceMappingsToLongTask<K,V>
6579	>	(map, this, b, rights, transformer, r, reducer)).fork();
6580	>	V v;
6581	>	while ((v = advance()) != null)
6582	>	r = reducer.applyAsLong(r, transformer.applyAsLong(nextKey, v));
6583	>	result = r;
6584	>	CountedCompleter<?> c;
6585	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6586	>	MapReduceMappingsToLongTask<K,V>
6587	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6588	>	s = t.rights;
6589	>	while (s != null) {
6590	>	t.result = reducer.applyAsLong(t.result, s.result);
6591	>	s = t.rights = s.nextRight;
6592	>	}
6593	>	}
6594	>	}
6595	>	}
6596	>	}
6597	>
6598	>	@SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6599	>	extends Traverser<K,V,Integer> {
6600	>	final ToIntFunction<? super K> transformer;
6601	>	final IntBinaryOperator reducer;
6602	>	final int basis;
6603	>	int result;
6604	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6605	>	MapReduceKeysToIntTask
6606	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6607	>	MapReduceKeysToIntTask<K,V> nextRight,
6608	>	ToIntFunction<? super K> transformer,
6609	>	int basis,
6610	>	IntBinaryOperator reducer) {
6611	>	super(m, p, b); this.nextRight = nextRight;
6612	>	this.transformer = transformer;
6613	>	this.basis = basis; this.reducer = reducer;
6614	>	}
6615	>	public final Integer getRawResult() { return result; }
6616	>	@SuppressWarnings("unchecked") public final void compute() {
6617	>	final ToIntFunction<? super K> transformer;
6618	>	final IntBinaryOperator reducer;
6619	>	if ((transformer = this.transformer) != null &&
6620	>	(reducer = this.reducer) != null) {
6621	>	int r = this.basis;
6622	>	for (int b; (b = preSplit()) > 0;)
6623	>	(rights = new MapReduceKeysToIntTask<K,V>
6624	>	(map, this, b, rights, transformer, r, reducer)).fork();
6625	>	while (advance() != null)
6626	>	r = reducer.applyAsInt(r, transformer.applyAsInt(nextKey));
6627	>	result = r;
6628	>	CountedCompleter<?> c;
6629	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6630	>	MapReduceKeysToIntTask<K,V>
6631	>	t = (MapReduceKeysToIntTask<K,V>)c,
6632	>	s = t.rights;
6633	>	while (s != null) {
6634	>	t.result = reducer.applyAsInt(t.result, s.result);
6635	>	s = t.rights = s.nextRight;
6636	>	}
6637	>	}
6638	>	}
6639	>	}
6640	>	}
6641	>
6642	>	@SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6643	>	extends Traverser<K,V,Integer> {
6644	>	final ToIntFunction<? super V> transformer;
6645	>	final IntBinaryOperator reducer;
6646	>	final int basis;
6647	>	int result;
6648	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6649	>	MapReduceValuesToIntTask
6650	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6651	>	MapReduceValuesToIntTask<K,V> nextRight,
6652	>	ToIntFunction<? super V> transformer,
6653	>	int basis,
6654	>	IntBinaryOperator reducer) {
6655	>	super(m, p, b); this.nextRight = nextRight;
6656	>	this.transformer = transformer;
6657	>	this.basis = basis; this.reducer = reducer;
6658	>	}
6659	>	public final Integer getRawResult() { return result; }
6660	>	@SuppressWarnings("unchecked") public final void compute() {
6661	>	final ToIntFunction<? super V> transformer;
6662	>	final IntBinaryOperator reducer;
6663	>	if ((transformer = this.transformer) != null &&
6664	>	(reducer = this.reducer) != null) {
6665	>	int r = this.basis;
6666	>	for (int b; (b = preSplit()) > 0;)
6667	>	(rights = new MapReduceValuesToIntTask<K,V>
6668	>	(map, this, b, rights, transformer, r, reducer)).fork();
6669	>	V v;
6670	>	while ((v = advance()) != null)
6671	>	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
6672	>	result = r;
6673	>	CountedCompleter<?> c;
6674	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6675	>	MapReduceValuesToIntTask<K,V>
6676	>	t = (MapReduceValuesToIntTask<K,V>)c,
6677	>	s = t.rights;
6678	>	while (s != null) {
6679	>	t.result = reducer.applyAsInt(t.result, s.result);
6680	>	s = t.rights = s.nextRight;
6681	>	}
6682	>	}
6683	>	}
6684	>	}
6685	>	}
6686	>
6687	>	@SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6688	>	extends Traverser<K,V,Integer> {
6689	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6690	>	final IntBinaryOperator reducer;
6691	>	final int basis;
6692	>	int result;
6693	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6694	>	MapReduceEntriesToIntTask
6695	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6696	>	MapReduceEntriesToIntTask<K,V> nextRight,
6697	>	ToIntFunction<Map.Entry<K,V>> transformer,
6698	>	int basis,
6699	>	IntBinaryOperator reducer) {
6700	>	super(m, p, b); this.nextRight = nextRight;
6701	>	this.transformer = transformer;
6702	>	this.basis = basis; this.reducer = reducer;
6703	>	}
6704	>	public final Integer getRawResult() { return result; }
6705	>	@SuppressWarnings("unchecked") public final void compute() {
6706	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6707	>	final IntBinaryOperator reducer;
6708	>	if ((transformer = this.transformer) != null &&
6709	>	(reducer = this.reducer) != null) {
6710	>	int r = this.basis;
6711	>	for (int b; (b = preSplit()) > 0;)
6712	>	(rights = new MapReduceEntriesToIntTask<K,V>
6713	>	(map, this, b, rights, transformer, r, reducer)).fork();
6714	>	V v;
6715	>	while ((v = advance()) != null)
6716	>	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor(nextKey,
6717	>	v)));
6718	>	result = r;
6719	>	CountedCompleter<?> c;
6720	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6721	>	MapReduceEntriesToIntTask<K,V>
6722	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6723	>	s = t.rights;
6724	>	while (s != null) {
6725	>	t.result = reducer.applyAsInt(t.result, s.result);
6726	>	s = t.rights = s.nextRight;
6727	>	}
6728	>	}
6729	>	}
6730	>	}
6731	>	}
6732	>
6733	>	@SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6734	>	extends Traverser<K,V,Integer> {
6735	>	final ToIntBiFunction<? super K, ? super V> transformer;
6736	>	final IntBinaryOperator reducer;
6737	>	final int basis;
6738	>	int result;
6739	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6740	>	MapReduceMappingsToIntTask
6741	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6742	>	MapReduceMappingsToIntTask<K,V> nextRight,
6743	>	ToIntBiFunction<? super K, ? super V> transformer,
6744	>	int basis,
6745	>	IntBinaryOperator reducer) {
6746	>	super(m, p, b); this.nextRight = nextRight;
6747	>	this.transformer = transformer;
6748	>	this.basis = basis; this.reducer = reducer;
6749	>	}
6750	>	public final Integer getRawResult() { return result; }
6751	>	@SuppressWarnings("unchecked") public final void compute() {
6752	>	final ToIntBiFunction<? super K, ? super V> transformer;
6753	>	final IntBinaryOperator reducer;
6754	>	if ((transformer = this.transformer) != null &&
6755	>	(reducer = this.reducer) != null) {
6756	>	int r = this.basis;
6757	>	for (int b; (b = preSplit()) > 0;)
6758	>	(rights = new MapReduceMappingsToIntTask<K,V>
6759	>	(map, this, b, rights, transformer, r, reducer)).fork();
6760	>	V v;
6761	>	while ((v = advance()) != null)
6762	>	r = reducer.applyAsInt(r, transformer.applyAsInt(nextKey, v));
6763	>	result = r;
6764	>	CountedCompleter<?> c;
6765	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6766	>	MapReduceMappingsToIntTask<K,V>
6767	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6768	>	s = t.rights;
6769	>	while (s != null) {
6770	>	t.result = reducer.applyAsInt(t.result, s.result);
6771	>	s = t.rights = s.nextRight;
6772	>	}
6773	>	}
6774	>	}
6775		}
6776		}
6777
6778		// Unsafe mechanics
6779	<	private static final sun.misc.Unsafe UNSAFE;
6780	<	private static final long SBASE;
6781	<	private static final int SSHIFT;
6782	<	private static final long TBASE;
6783	<	private static final int TSHIFT;
6779	>	private static final sun.misc.Unsafe U;
6780	>	private static final long SIZECTL;
6781	>	private static final long TRANSFERINDEX;
6782	>	private static final long TRANSFERORIGIN;
6783	>	private static final long BASECOUNT;
6784	>	private static final long CELLSBUSY;
6785	>	private static final long CELLVALUE;
6786	>	private static final long ABASE;
6787	>	private static final int ASHIFT;
6788
6789		static {
1474	–	int ss, ts;
6790		try {
6791	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
6792	<	Class tc = HashEntry[].class;
6793	<	Class sc = Segment[].class;
6794	<	TBASE = UNSAFE.arrayBaseOffset(tc);
6795	<	SBASE = UNSAFE.arrayBaseOffset(sc);
6796	<	ts = UNSAFE.arrayIndexScale(tc);
6797	<	ss = UNSAFE.arrayIndexScale(sc);
6791	>	U = sun.misc.Unsafe.getUnsafe();
6792	>	Class<?> k = ConcurrentHashMap.class;
6793	>	SIZECTL = U.objectFieldOffset
6794	>	(k.getDeclaredField("sizeCtl"));
6795	>	TRANSFERINDEX = U.objectFieldOffset
6796	>	(k.getDeclaredField("transferIndex"));
6797	>	TRANSFERORIGIN = U.objectFieldOffset
6798	>	(k.getDeclaredField("transferOrigin"));
6799	>	BASECOUNT = U.objectFieldOffset
6800	>	(k.getDeclaredField("baseCount"));
6801	>	CELLSBUSY = U.objectFieldOffset
6802	>	(k.getDeclaredField("cellsBusy"));
6803	>	Class<?> ck = Cell.class;
6804	>	CELLVALUE = U.objectFieldOffset
6805	>	(ck.getDeclaredField("value"));
6806	>	Class<?> sc = Node[].class;
6807	>	ABASE = U.arrayBaseOffset(sc);
6808	>	int scale = U.arrayIndexScale(sc);
6809	>	if ((scale & (scale - 1)) != 0)
6810	>	throw new Error("data type scale not a power of two");
6811	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6812		} catch (Exception e) {
6813		throw new Error(e);
6814		}
1486	–	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
1487	–	throw new Error("data type scale not a power of two");
1488	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1489	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
6815		}
6816
6817		}

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