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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.115 by jsr166, Fri Dec 2 14:28:17 2011 UTC vs.
Revision 1.199 by dl, Wed Mar 27 19:46:34 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.Spliterator;
11	>	import java.util.stream.Stream;
12	>	import java.util.stream.Streams;
13	>	import java.util.function.*;
14	>	import java.util.function.Consumer;
15	>	import java.util.function.Function;
16	>	import java.util.function.BiFunction;
17	>
18	>	import java.util.Comparator;
19	>	import java.util.Arrays;
20	>	import java.util.Map;
21	>	import java.util.Set;
22	>	import java.util.Collection;
23	>	import java.util.AbstractMap;
24	>	import java.util.AbstractSet;
25	>	import java.util.AbstractCollection;
26	>	import java.util.Hashtable;
27	>	import java.util.HashMap;
28	>	import java.util.Iterator;
29	>	import java.util.Enumeration;
30	>	import java.util.ConcurrentModificationException;
31	>	import java.util.NoSuchElementException;
32	>	import java.util.concurrent.ConcurrentMap;
33	>	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
34	>	import java.util.concurrent.atomic.AtomicInteger;
35	>	import java.util.concurrent.atomic.AtomicReference;
36		import java.io.Serializable;
37
38		/**
39		* A hash table supporting full concurrency of retrievals and
40	<	* adjustable expected concurrency for updates. This class obeys the
40	>	* high expected concurrency for updates. This class obeys the
41		* same functional specification as {@link java.util.Hashtable}, and
42		* includes versions of methods corresponding to each method of
43	<	* <tt>Hashtable</tt>. However, even though all operations are
43	>	* {@code Hashtable}. However, even though all operations are
44		* thread-safe, retrieval operations do <em>not</em> entail locking,
45		* and there is <em>not</em> any support for locking the entire table
46		* in a way that prevents all access.  This class is fully
47	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
47	>	* interoperable with {@code Hashtable} in programs that rely on its
48		* thread safety but not on its synchronization details.
49		*
50	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
51	<	* block, so may overlap with update operations (including
52	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
53	<	* of the most recently <em>completed</em> update operations holding
54	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
55	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
56	<	* removal of only some entries.  Similarly, Iterators and
57	<	* Enumerations return elements reflecting the state of the hash table
58	<	* at some point at or since the creation of the iterator/enumeration.
59	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
60	<	* However, iterators are designed to be used by only one thread at a time.
61	<	*
62	<	* <p> The allowed concurrency among update operations is guided by
63	<	* the optional <tt>concurrencyLevel</tt> constructor argument
64	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
65	<	* table is internally partitioned to try to permit the indicated
66	<	* number of concurrent updates without contention. Because placement
67	<	* in hash tables is essentially random, the actual concurrency will
68	<	* vary.  Ideally, you should choose a value to accommodate as many
69	<	* threads as will ever concurrently modify the table. Using a
70	<	* significantly higher value than you need can waste space and time,
71	<	* and a significantly lower value can lead to thread contention. But
72	<	* overestimates and underestimates within an order of magnitude do
73	<	* not usually have much noticeable impact. A value of one is
74	<	* appropriate when it is known that only one thread will modify and
75	<	* all others will only read. Also, resizing this or any other kind of
76	<	* hash table is a relatively slow operation, so, when possible, it is
77	<	* a good idea to provide estimates of expected table sizes in
78	<	* constructors.
50	>	* <p>Retrieval operations (including {@code get}) generally do not
51	>	* block, so may overlap with update operations (including {@code put}
52	>	* and {@code remove}). Retrievals reflect the results of the most
53	>	* recently <em>completed</em> update operations holding upon their
54	>	* onset. (More formally, an update operation for a given key bears a
55	>	* <em>happens-before</em> relation with any (non-null) retrieval for
56	>	* that key reporting the updated value.)  For aggregate operations
57	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
58	>	* reflect insertion or removal of only some entries.  Similarly,
59	>	* Iterators and Enumerations return elements reflecting the state of
60	>	* the hash table at some point at or since the creation of the
61	>	* iterator/enumeration.  They do <em>not</em> throw {@link
62	>	* ConcurrentModificationException}.  However, iterators are designed
63	>	* to be used by only one thread at a time.  Bear in mind that the
64	>	* results of aggregate status methods including {@code size}, {@code
65	>	* isEmpty}, and {@code containsValue} are typically useful only when
66	>	* a map is not undergoing concurrent updates in other threads.
67	>	* Otherwise the results of these methods reflect transient states
68	>	* that may be adequate for monitoring or estimation purposes, but not
69	>	* for program control.
70	>	*
71	>	* <p>The table is dynamically expanded when there are too many
72	>	* collisions (i.e., keys that have distinct hash codes but fall into
73	>	* the same slot modulo the table size), with the expected average
74	>	* effect of maintaining roughly two bins per mapping (corresponding
75	>	* to a 0.75 load factor threshold for resizing). There may be much
76	>	* variance around this average as mappings are added and removed, but
77	>	* overall, this maintains a commonly accepted time/space tradeoff for
78	>	* hash tables.  However, resizing this or any other kind of hash
79	>	* table may be a relatively slow operation. When possible, it is a
80	>	* good idea to provide a size estimate as an optional {@code
81	>	* initialCapacity} constructor argument. An additional optional
82	>	* {@code loadFactor} constructor argument provides a further means of
83	>	* customizing initial table capacity by specifying the table density
84	>	* to be used in calculating the amount of space to allocate for the
85	>	* given number of elements.  Also, for compatibility with previous
86	>	* versions of this class, constructors may optionally specify an
87	>	* expected {@code concurrencyLevel} as an additional hint for
88	>	* internal sizing.  Note that using many keys with exactly the same
89	>	* {@code hashCode()} is a sure way to slow down performance of any
90	>	* hash table.
91	>	*
92	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
93	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
94	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
95	>	* mapped values are (perhaps transiently) not used or all take the
96	>	* same mapping value.
97	>	*
98	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
99	>	* form of histogram or multiset) by using {@link
100	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
101	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
102	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
103	>	* {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();}
104		*
105		* <p>This class and its views and iterators implement all of the
106		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
107		* interfaces.
108		*
109	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
110	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
109	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
110	>	* does <em>not</em> allow {@code null} to be used as a key or value.
111	>	*
112	>	* <p>ConcurrentHashMaps support sequential and parallel operations
113	>	* bulk operations. (Parallel forms use the {@link
114	>	* ForkJoinPool#commonPool()}). Tasks that may be used in other
115	>	* contexts are available in class {@link ForkJoinTasks}. These
116	>	* operations are designed to be safely, and often sensibly, applied
117	>	* even with maps that are being concurrently updated by other
118	>	* threads; for example, when computing a snapshot summary of the
119	>	* values in a shared registry.  There are three kinds of operation,
120	>	* each with four forms, accepting functions with Keys, Values,
121	>	* Entries, and (Key, Value) arguments and/or return values. Because
122	>	* the elements of a ConcurrentHashMap are not ordered in any
123	>	* particular way, and may be processed in different orders in
124	>	* different parallel executions, the correctness of supplied
125	>	* functions should not depend on any ordering, or on any other
126	>	* objects or values that may transiently change while computation is
127	>	* in progress; and except for forEach actions, should ideally be
128	>	* side-effect-free.
129	>	*
130	>	* <ul>
131	>	* <li> forEach: Perform a given action on each element.
132	>	* A variant form applies a given transformation on each element
133	>	* before performing the action.</li>
134	>	*
135	>	* <li> search: Return the first available non-null result of
136	>	* applying a given function on each element; skipping further
137	>	* search when a result is found.</li>
138	>	*
139	>	* <li> reduce: Accumulate each element.  The supplied reduction
140	>	* function cannot rely on ordering (more formally, it should be
141	>	* both associative and commutative).  There are five variants:
142	>	*
143	>	* <ul>
144	>	*
145	>	* <li> Plain reductions. (There is not a form of this method for
146	>	* (key, value) function arguments since there is no corresponding
147	>	* return type.)</li>
148	>	*
149	>	* <li> Mapped reductions that accumulate the results of a given
150	>	* function applied to each element.</li>
151	>	*
152	>	* <li> Reductions to scalar doubles, longs, and ints, using a
153	>	* given basis value.</li>
154	>	*
155	>	* </ul>
156	>	* </li>
157	>	* </ul>
158	>	*
159	>	* <p>The concurrency properties of bulk operations follow
160	>	* from those of ConcurrentHashMap: Any non-null result returned
161	>	* from {@code get(key)} and related access methods bears a
162	>	* happens-before relation with the associated insertion or
163	>	* update.  The result of any bulk operation reflects the
164	>	* composition of these per-element relations (but is not
165	>	* necessarily atomic with respect to the map as a whole unless it
166	>	* is somehow known to be quiescent).  Conversely, because keys
167	>	* and values in the map are never null, null serves as a reliable
168	>	* atomic indicator of the current lack of any result.  To
169	>	* maintain this property, null serves as an implicit basis for
170	>	* all non-scalar reduction operations. For the double, long, and
171	>	* int versions, the basis should be one that, when combined with
172	>	* any other value, returns that other value (more formally, it
173	>	* should be the identity element for the reduction). Most common
174	>	* reductions have these properties; for example, computing a sum
175	>	* with basis 0 or a minimum with basis MAX_VALUE.
176	>	*
177	>	* <p>Search and transformation functions provided as arguments
178	>	* should similarly return null to indicate the lack of any result
179	>	* (in which case it is not used). In the case of mapped
180	>	* reductions, this also enables transformations to serve as
181	>	* filters, returning null (or, in the case of primitive
182	>	* specializations, the identity basis) if the element should not
183	>	* be combined. You can create compound transformations and
184	>	* filterings by composing them yourself under this "null means
185	>	* there is nothing there now" rule before using them in search or
186	>	* reduce operations.
187	>	*
188	>	* <p>Methods accepting and/or returning Entry arguments maintain
189	>	* key-value associations. They may be useful for example when
190	>	* finding the key for the greatest value. Note that "plain" Entry
191	>	* arguments can be supplied using {@code new
192	>	* AbstractMap.SimpleEntry(k,v)}.
193	>	*
194	>	* <p>Bulk operations may complete abruptly, throwing an
195	>	* exception encountered in the application of a supplied
196	>	* function. Bear in mind when handling such exceptions that other
197	>	* concurrently executing functions could also have thrown
198	>	* exceptions, or would have done so if the first exception had
199	>	* not occurred.
200	>	*
201	>	* <p>Speedups for parallel compared to sequential forms are common
202	>	* but not guaranteed.  Parallel operations involving brief functions
203	>	* on small maps may execute more slowly than sequential forms if the
204	>	* underlying work to parallelize the computation is more expensive
205	>	* than the computation itself.  Similarly, parallelization may not
206	>	* lead to much actual parallelism if all processors are busy
207	>	* performing unrelated tasks.
208	>	*
209	>	* <p>All arguments to all task methods must be non-null.
210		*
211		* <p>This class is a member of the
212		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 67 | Line 217 | import java.io.Serializable;
217		* @param <K> the type of keys maintained by this map
218		* @param <V> the type of mapped values
219		*/
220	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
221	<	implements ConcurrentMap<K, V>, Serializable {
220	>	public class ConcurrentHashMap<K,V>
221	>	implements ConcurrentMap<K,V>, Serializable {
222		private static final long serialVersionUID = 7249069246763182397L;
223
224		/*
225	<	* The basic strategy is to subdivide the table among Segments,
226	<	* each of which itself is a concurrently readable hash table.  To
227	<	* reduce footprint, all but one segments are constructed only
228	<	* when first needed (see ensureSegment). To maintain visibility
229	<	* in the presence of lazy construction, accesses to segments as
230	<	* well as elements of segment's table must use volatile access,
231	<	* which is done via Unsafe within methods segmentAt etc
232	<	* below. These provide the functionality of AtomicReferenceArrays
233	<	* but reduce the levels of indirection. Additionally,
234	<	* volatile-writes of table elements and entry "next" fields
235	<	* within locked operations use the cheaper "lazySet" forms of
236	<	* writes (via putOrderedObject) because these writes are always
237	<	* followed by lock releases that maintain sequential consistency
238	<	* of table updates.
239	<	*
240	<	* Historical note: The previous version of this class relied
241	<	* heavily on "final" fields, which avoided some volatile reads at
242	<	* the expense of a large initial footprint.  Some remnants of
243	<	* that design (including forced construction of segment 0) exist
244	<	* to ensure serialization compatibility.
225	>	* Overview:
226	>	*
227	>	* The primary design goal of this hash table is to maintain
228	>	* concurrent readability (typically method get(), but also
229	>	* iterators and related methods) while minimizing update
230	>	* contention. Secondary goals are to keep space consumption about
231	>	* the same or better than java.util.HashMap, and to support high
232	>	* initial insertion rates on an empty table by many threads.
233	>	*
234	>	* Each key-value mapping is held in a Node.  Because Node key
235	>	* fields can contain special values, they are defined using plain
236	>	* Object types (not type "K"). This leads to a lot of explicit
237	>	* casting (and many explicit warning suppressions to tell
238	>	* compilers not to complain about it). It also allows some of the
239	>	* public methods to be factored into a smaller number of internal
240	>	* methods (although sadly not so for the five variants of
241	>	* put-related operations). The validation-based approach
242	>	* explained below leads to a lot of code sprawl because
243	>	* retry-control precludes factoring into smaller methods.
244	>	*
245	>	* The table is lazily initialized to a power-of-two size upon the
246	>	* first insertion.  Each bin in the table normally contains a
247	>	* list of Nodes (most often, the list has only zero or one Node).
248	>	* Table accesses require volatile/atomic reads, writes, and
249	>	* CASes.  Because there is no other way to arrange this without
250	>	* adding further indirections, we use intrinsics
251	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
252	>	* are always accurately traversable under volatile reads, so long
253	>	* as lookups check hash code and non-nullness of value before
254	>	* checking key equality.
255	>	*
256	>	* We use the top (sign) bit of Node hash fields for control
257	>	* purposes -- it is available anyway because of addressing
258	>	* constraints.  Nodes with negative hash fields are forwarding
259	>	* nodes to either TreeBins or resized tables.  The lower 31 bits
260	>	* of each normal Node's hash field contain a transformation of
261	>	* the key's hash code.
262	>	*
263	>	* Insertion (via put or its variants) of the first node in an
264	>	* empty bin is performed by just CASing it to the bin.  This is
265	>	* by far the most common case for put operations under most
266	>	* key/hash distributions.  Other update operations (insert,
267	>	* delete, and replace) require locks.  We do not want to waste
268	>	* the space required to associate a distinct lock object with
269	>	* each bin, so instead use the first node of a bin list itself as
270	>	* a lock. Locking support for these locks relies on builtin
271	>	* "synchronized" monitors.
272	>	*
273	>	* Using the first node of a list as a lock does not by itself
274	>	* suffice though: When a node is locked, any update must first
275	>	* validate that it is still the first node after locking it, and
276	>	* retry if not. Because new nodes are always appended to lists,
277	>	* once a node is first in a bin, it remains first until deleted
278	>	* or the bin becomes invalidated (upon resizing).  However,
279	>	* operations that only conditionally update may inspect nodes
280	>	* until the point of update. This is a converse of sorts to the
281	>	* lazy locking technique described by Herlihy & Shavit.
282	>	*
283	>	* The main disadvantage of per-bin locks is that other update
284	>	* operations on other nodes in a bin list protected by the same
285	>	* lock can stall, for example when user equals() or mapping
286	>	* functions take a long time.  However, statistically, under
287	>	* random hash codes, this is not a common problem.  Ideally, the
288	>	* frequency of nodes in bins follows a Poisson distribution
289	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
290	>	* parameter of about 0.5 on average, given the resizing threshold
291	>	* of 0.75, although with a large variance because of resizing
292	>	* granularity. Ignoring variance, the expected occurrences of
293	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
294	>	* first values are:
295	>	*
296	>	* 0:    0.60653066
297	>	* 1:    0.30326533
298	>	* 2:    0.07581633
299	>	* 3:    0.01263606
300	>	* 4:    0.00157952
301	>	* 5:    0.00015795
302	>	* 6:    0.00001316
303	>	* 7:    0.00000094
304	>	* 8:    0.00000006
305	>	* more: less than 1 in ten million
306	>	*
307	>	* Lock contention probability for two threads accessing distinct
308	>	* elements is roughly 1 / (8 * #elements) under random hashes.
309	>	*
310	>	* Actual hash code distributions encountered in practice
311	>	* sometimes deviate significantly from uniform randomness.  This
312	>	* includes the case when N > (1<<30), so some keys MUST collide.
313	>	* Similarly for dumb or hostile usages in which multiple keys are
314	>	* designed to have identical hash codes. Also, although we guard
315	>	* against the worst effects of this (see method spread), sets of
316	>	* hashes may differ only in bits that do not impact their bin
317	>	* index for a given power-of-two mask.  So we use a secondary
318	>	* strategy that applies when the number of nodes in a bin exceeds
319	>	* a threshold, and at least one of the keys implements
320	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
321	>	* (a specialized form of red-black trees), bounding search time
322	>	* to O(log N).  Each search step in a TreeBin is around twice as
323	>	* slow as in a regular list, but given that N cannot exceed
324	>	* (1<<64) (before running out of addresses) this bounds search
325	>	* steps, lock hold times, etc, to reasonable constants (roughly
326	>	* 100 nodes inspected per operation worst case) so long as keys
327	>	* are Comparable (which is very common -- String, Long, etc).
328	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
329	>	* traversal pointers as regular nodes, so can be traversed in
330	>	* iterators in the same way.
331	>	*
332	>	* The table is resized when occupancy exceeds a percentage
333	>	* threshold (nominally, 0.75, but see below).  Any thread
334	>	* noticing an overfull bin may assist in resizing after the
335	>	* initiating thread allocates and sets up the replacement
336	>	* array. However, rather than stalling, these other threads may
337	>	* proceed with insertions etc.  The use of TreeBins shields us
338	>	* from the worst case effects of overfilling while resizes are in
339	>	* progress.  Resizing proceeds by transferring bins, one by one,
340	>	* from the table to the next table. To enable concurrency, the
341	>	* next table must be (incrementally) prefilled with place-holders
342	>	* serving as reverse forwarders to the old table.  Because we are
343	>	* using power-of-two expansion, the elements from each bin must
344	>	* either stay at same index, or move with a power of two
345	>	* offset. We eliminate unnecessary node creation by catching
346	>	* cases where old nodes can be reused because their next fields
347	>	* won't change.  On average, only about one-sixth of them need
348	>	* cloning when a table doubles. The nodes they replace will be
349	>	* garbage collectable as soon as they are no longer referenced by
350	>	* any reader thread that may be in the midst of concurrently
351	>	* traversing table.  Upon transfer, the old table bin contains
352	>	* only a special forwarding node (with hash field "MOVED") that
353	>	* contains the next table as its key. On encountering a
354	>	* forwarding node, access and update operations restart, using
355	>	* the new table.
356	>	*
357	>	* Each bin transfer requires its bin lock, which can stall
358	>	* waiting for locks while resizing. However, because other
359	>	* threads can join in and help resize rather than contend for
360	>	* locks, average aggregate waits become shorter as resizing
361	>	* progresses.  The transfer operation must also ensure that all
362	>	* accessible bins in both the old and new table are usable by any
363	>	* traversal.  This is arranged by proceeding from the last bin
364	>	* (table.length - 1) up towards the first.  Upon seeing a
365	>	* forwarding node, traversals (see class Traverser) arrange to
366	>	* move to the new table without revisiting nodes.  However, to
367	>	* ensure that no intervening nodes are skipped, bin splitting can
368	>	* only begin after the associated reverse-forwarders are in
369	>	* place.
370	>	*
371	>	* The traversal scheme also applies to partial traversals of
372	>	* ranges of bins (via an alternate Traverser constructor)
373	>	* to support partitioned aggregate operations.  Also, read-only
374	>	* operations give up if ever forwarded to a null table, which
375	>	* provides support for shutdown-style clearing, which is also not
376	>	* currently implemented.
377	>	*
378	>	* Lazy table initialization minimizes footprint until first use,
379	>	* and also avoids resizings when the first operation is from a
380	>	* putAll, constructor with map argument, or deserialization.
381	>	* These cases attempt to override the initial capacity settings,
382	>	* but harmlessly fail to take effect in cases of races.
383	>	*
384	>	* The element count is maintained using a specialization of
385	>	* LongAdder. We need to incorporate a specialization rather than
386	>	* just use a LongAdder in order to access implicit
387	>	* contention-sensing that leads to creation of multiple
388	>	* Cells.  The counter mechanics avoid contention on
389	>	* updates but can encounter cache thrashing if read too
390	>	* frequently during concurrent access. To avoid reading so often,
391	>	* resizing under contention is attempted only upon adding to a
392	>	* bin already holding two or more nodes. Under uniform hash
393	>	* distributions, the probability of this occurring at threshold
394	>	* is around 13%, meaning that only about 1 in 8 puts check
395	>	* threshold (and after resizing, many fewer do so). The bulk
396	>	* putAll operation further reduces contention by only committing
397	>	* count updates upon these size checks.
398	>	*
399	>	* Maintaining API and serialization compatibility with previous
400	>	* versions of this class introduces several oddities. Mainly: We
401	>	* leave untouched but unused constructor arguments refering to
402	>	* concurrencyLevel. We accept a loadFactor constructor argument,
403	>	* but apply it only to initial table capacity (which is the only
404	>	* time that we can guarantee to honor it.) We also declare an
405	>	* unused "Segment" class that is instantiated in minimal form
406	>	* only when serializing.
407		*/
408
409		/* ---------------- Constants -------------- */
410
411		/**
412	<	* The default initial capacity for this table,
413	<	* used when not otherwise specified in a constructor.
412	>	* The largest possible table capacity.  This value must be
413	>	* exactly 1<<30 to stay within Java array allocation and indexing
414	>	* bounds for power of two table sizes, and is further required
415	>	* because the top two bits of 32bit hash fields are used for
416	>	* control purposes.
417		*/
418	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
418	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
419
420		/**
421	<	* The default load factor for this table, used when not
422	<	* otherwise specified in a constructor.
421	>	* The default initial table capacity.  Must be a power of 2
422	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
423		*/
424	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
424	>	private static final int DEFAULT_CAPACITY = 16;
425
426		/**
427	<	* The default concurrency level for this table, used when not
428	<	* otherwise specified in a constructor.
427	>	* The largest possible (non-power of two) array size.
428	>	* Needed by toArray and related methods.
429		*/
430	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
430	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
431
432		/**
433	<	* The maximum capacity, used if a higher value is implicitly
434	<	* specified by either of the constructors with arguments.  MUST
120	<	* be a power of two <= 1<<30 to ensure that entries are indexable
121	<	* using ints.
433	>	* The default concurrency level for this table. Unused but
434	>	* defined for compatibility with previous versions of this class.
435		*/
436	<	static final int MAXIMUM_CAPACITY = 1 << 30;
436	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
437
438		/**
439	<	* The minimum capacity for per-segment tables.  Must be a power
440	<	* of two, at least two to avoid immediate resizing on next use
441	<	* after lazy construction.
439	>	* The load factor for this table. Overrides of this value in
440	>	* constructors affect only the initial table capacity.  The
441	>	* actual floating point value isn't normally used -- it is
442	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
443	>	* the associated resizing threshold.
444		*/
445	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
445	>	private static final float LOAD_FACTOR = 0.75f;
446
447		/**
448	<	* The maximum number of segments to allow; used to bound
449	<	* constructor arguments. Must be power of two less than 1 << 24.
448	>	* The bin count threshold for using a tree rather than list for a
449	>	* bin.  The value reflects the approximate break-even point for
450	>	* using tree-based operations.
451		*/
452	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
452	>	private static final int TREE_THRESHOLD = 8;
453
454		/**
455	<	* Number of unsynchronized retries in size and containsValue
456	<	* methods before resorting to locking. This is used to avoid
457	<	* unbounded retries if tables undergo continuous modification
458	<	* which would make it impossible to obtain an accurate result.
455	>	* Minimum number of rebinnings per transfer step. Ranges are
456	>	* subdivided to allow multiple resizer threads.  This value
457	>	* serves as a lower bound to avoid resizers encountering
458	>	* excessive memory contention.  The value should be at least
459	>	* DEFAULT_CAPACITY.
460		*/
461	<	static final int RETRIES_BEFORE_LOCK = 2;
461	>	private static final int MIN_TRANSFER_STRIDE = 16;
462	>
463	>	/*
464	>	* Encodings for Node hash fields. See above for explanation.
465	>	*/
466	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
467	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
468	>
469	>	/** Number of CPUS, to place bounds on some sizings */
470	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
471	>
472	>	/* ---------------- Counters -------------- */
473	>
474	>	// Adapted from LongAdder and Striped64.
475	>	// See their internal docs for explanation.
476	>
477	>	// A padded cell for distributing counts
478	>	static final class Cell {
479	>	volatile long p0, p1, p2, p3, p4, p5, p6;
480	>	volatile long value;
481	>	volatile long q0, q1, q2, q3, q4, q5, q6;
482	>	Cell(long x) { value = x; }
483	>	}
484
485		/* ---------------- Fields -------------- */
486
487		/**
488	<	* Mask value for indexing into segments. The upper bits of a
489	<	* key's hash code are used to choose the segment.
488	>	* The array of bins. Lazily initialized upon first insertion.
489	>	* Size is always a power of two. Accessed directly by iterators.
490		*/
491	<	final int segmentMask;
491	>	transient volatile Node<V>[] table;
492
493		/**
494	<	* Shift value for indexing within segments.
494	>	* The next table to use; non-null only while resizing.
495		*/
496	<	final int segmentShift;
496	>	private transient volatile Node<V>[] nextTable;
497
498		/**
499	<	* The segments, each of which is a specialized hash table.
499	>	* Base counter value, used mainly when there is no contention,
500	>	* but also as a fallback during table initialization
501	>	* races. Updated via CAS.
502		*/
503	<	final Segment<K,V>[] segments;
503	>	private transient volatile long baseCount;
504
505	<	transient Set<K> keySet;
506	<	transient Set<Map.Entry<K,V>> entrySet;
507	<	transient Collection<V> values;
505	>	/**
506	>	* Table initialization and resizing control.  When negative, the
507	>	* table is being initialized or resized: -1 for initialization,
508	>	* else -(1 + the number of active resizing threads).  Otherwise,
509	>	* when table is null, holds the initial table size to use upon
510	>	* creation, or 0 for default. After initialization, holds the
511	>	* next element count value upon which to resize the table.
512	>	*/
513	>	private transient volatile int sizeCtl;
514	>
515	>	/**
516	>	* The next table index (plus one) to split while resizing.
517	>	*/
518	>	private transient volatile int transferIndex;
519
520		/**
521	<	* ConcurrentHashMap list entry. Note that this is never exported
170	<	* out as a user-visible Map.Entry.
521	>	* The least available table index to split while resizing.
522		*/
523	<	static final class HashEntry<K,V> {
523	>	private transient volatile int transferOrigin;
524	>
525	>	/**
526	>	* Spinlock (locked via CAS) used when resizing and/or creating Cells.
527	>	*/
528	>	private transient volatile int cellsBusy;
529	>
530	>	/**
531	>	* Table of counter cells. When non-null, size is a power of 2.
532	>	*/
533	>	private transient volatile Cell[] counterCells;
534	>
535	>	// views
536	>	private transient KeySetView<K,V> keySet;
537	>	private transient ValuesView<K,V> values;
538	>	private transient EntrySetView<K,V> entrySet;
539	>
540	>	/** For serialization compatibility. Null unless serialized; see below */
541	>	private Segment<K,V>[] segments;
542	>
543	>	/* ---------------- Table element access -------------- */
544	>
545	>	/*
546	>	* Volatile access methods are used for table elements as well as
547	>	* elements of in-progress next table while resizing.  Uses are
548	>	* null checked by callers, and implicitly bounds-checked, relying
549	>	* on the invariants that tab arrays have non-zero size, and all
550	>	* indices are masked with (tab.length - 1) which is never
551	>	* negative and always less than length. Note that, to be correct
552	>	* wrt arbitrary concurrency errors by users, bounds checks must
553	>	* operate on local variables, which accounts for some odd-looking
554	>	* inline assignments below.
555	>	*/
556	>
557	>	@SuppressWarnings("unchecked") static final <V> Node<V> tabAt
558	>	(Node<V>[] tab, int i) { // used by Traverser
559	>	return (Node<V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
560	>	}
561	>
562	>	private static final <V> boolean casTabAt
563	>	(Node<V>[] tab, int i, Node<V> c, Node<V> v) {
564	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
565	>	}
566	>
567	>	private static final <V> void setTabAt
568	>	(Node<V>[] tab, int i, Node<V> v) {
569	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
570	>	}
571	>
572	>	/* ---------------- Nodes -------------- */
573	>
574	>	/**
575	>	* Key-value entry. Note that this is never exported out as a
576	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
577	>	* field of MOVED are special, and do not contain user keys or
578	>	* values.  Otherwise, keys are never null, and null val fields
579	>	* indicate that a node is in the process of being deleted or
580	>	* created. For purposes of read-only access, a key may be read
581	>	* before a val, but can only be used after checking val to be
582	>	* non-null.
583	>	*/
584	>	static class Node<V> {
585		final int hash;
586	<	final K key;
587	<	volatile V value;
588	<	volatile HashEntry<K,V> next;
586	>	final Object key;
587	>	volatile V val;
588	>	volatile Node<V> next;
589
590	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
590	>	Node(int hash, Object key, V val, Node<V> next) {
591		this.hash = hash;
592		this.key = key;
593	<	this.value = value;
593	>	this.val = val;
594		this.next = next;
595		}
596	+	}
597
598	<	/**
186	<	* Sets next field with volatile write semantics.  (See above
187	<	* about use of putOrderedObject.)
188	<	*/
189	<	final void setNext(HashEntry<K,V> n) {
190	<	UNSAFE.putOrderedObject(this, nextOffset, n);
191	<	}
598	>	/* ---------------- TreeBins -------------- */
599
600	<	// Unsafe mechanics
601	<	static final sun.misc.Unsafe UNSAFE;
602	<	static final long nextOffset;
603	<	static {
604	<	try {
605	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
606	<	Class<?> k = HashEntry.class;
607	<	nextOffset = UNSAFE.objectFieldOffset
608	<	(k.getDeclaredField("next"));
609	<	} catch (Exception e) {
610	<	throw new Error(e);
611	<	}
600	>	/**
601	>	* Nodes for use in TreeBins
602	>	*/
603	>	static final class TreeNode<V> extends Node<V> {
604	>	TreeNode<V> parent;  // red-black tree links
605	>	TreeNode<V> left;
606	>	TreeNode<V> right;
607	>	TreeNode<V> prev;    // needed to unlink next upon deletion
608	>	boolean red;
609	>
610	>	TreeNode(int hash, Object key, V val, Node<V> next, TreeNode<V> parent) {
611	>	super(hash, key, val, next);
612	>	this.parent = parent;
613		}
614		}
615
616		/**
617	<	* Gets the ith element of given table (if nonnull) with volatile
618	<	* read semantics. Note: This is manually integrated into a few
619	<	* performance-sensitive methods to reduce call overhead.
620	<	*/
621	<	@SuppressWarnings("unchecked")
622	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
623	<	return (tab == null) ? null :
624	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
625	<	(tab, ((long)i << TSHIFT) + TBASE);
626	<	}
627	<
628	<	/**
629	<	* Sets the ith element of given table, with volatile write
630	<	* semantics. (See above about use of putOrderedObject.)
631	<	*/
632	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
633	<	HashEntry<K,V> e) {
634	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
635	<	}
636	<
637	<	/**
638	<	* Applies a supplemental hash function to a given hashCode, which
639	<	* defends against poor quality hash functions.  This is critical
640	<	* because ConcurrentHashMap uses power-of-two length hash tables,
641	<	* that otherwise encounter collisions for hashCodes that do not
642	<	* differ in lower or upper bits.
643	<	*/
644	<	private static int hash(int h) {
645	<	// Spread bits to regularize both segment and index locations,
646	<	// using variant of single-word Wang/Jenkins hash.
647	<	h += (h <<  15) ^ 0xffffcd7d;
648	<	h ^= (h >>> 10);
649	<	h += (h <<   3);
650	<	h ^= (h >>>  6);
651	<	h += (h <<   2) + (h << 14);
652	<	return h ^ (h >>> 16);
653	<	}
654	<
655	<	/**
656	<	* Segments are specialized versions of hash tables.  This
657	<	* subclasses from ReentrantLock opportunistically, just to
658	<	* simplify some locking and avoid separate construction.
659	<	*/
252	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
253	<	/*
254	<	* Segments maintain a table of entry lists that are always
255	<	* kept in a consistent state, so can be read (via volatile
256	<	* reads of segments and tables) without locking.  This
257	<	* requires replicating nodes when necessary during table
258	<	* resizing, so the old lists can be traversed by readers
259	<	* still using old version of table.
260	<	*
261	<	* This class defines only mutative methods requiring locking.
262	<	* Except as noted, the methods of this class perform the
263	<	* per-segment versions of ConcurrentHashMap methods.  (Other
264	<	* methods are integrated directly into ConcurrentHashMap
265	<	* methods.) These mutative methods use a form of controlled
266	<	* spinning on contention via methods scanAndLock and
267	<	* scanAndLockForPut. These intersperse tryLocks with
268	<	* traversals to locate nodes.  The main benefit is to absorb
269	<	* cache misses (which are very common for hash tables) while
270	<	* obtaining locks so that traversal is faster once
271	<	* acquired. We do not actually use the found nodes since they
272	<	* must be re-acquired under lock anyway to ensure sequential
273	<	* consistency of updates (and in any case may be undetectably
274	<	* stale), but they will normally be much faster to re-locate.
275	<	* Also, scanAndLockForPut speculatively creates a fresh node
276	<	* to use in put if no node is found.
277	<	*/
278	<
617	>	* A specialized form of red-black tree for use in bins
618	>	* whose size exceeds a threshold.
619	>	*
620	>	* TreeBins use a special form of comparison for search and
621	>	* related operations (which is the main reason we cannot use
622	>	* existing collections such as TreeMaps). TreeBins contain
623	>	* Comparable elements, but may contain others, as well as
624	>	* elements that are Comparable but not necessarily Comparable<T>
625	>	* for the same T, so we cannot invoke compareTo among them. To
626	>	* handle this, the tree is ordered primarily by hash value, then
627	>	* by getClass().getName() order, and then by Comparator order
628	>	* among elements of the same class.  On lookup at a node, if
629	>	* elements are not comparable or compare as 0, both left and
630	>	* right children may need to be searched in the case of tied hash
631	>	* values. (This corresponds to the full list search that would be
632	>	* necessary if all elements were non-Comparable and had tied
633	>	* hashes.)  The red-black balancing code is updated from
634	>	* pre-jdk-collections
635	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
636	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
637	>	* Algorithms" (CLR).
638	>	*
639	>	* TreeBins also maintain a separate locking discipline than
640	>	* regular bins. Because they are forwarded via special MOVED
641	>	* nodes at bin heads (which can never change once established),
642	>	* we cannot use those nodes as locks. Instead, TreeBin
643	>	* extends AbstractQueuedSynchronizer to support a simple form of
644	>	* read-write lock. For update operations and table validation,
645	>	* the exclusive form of lock behaves in the same way as bin-head
646	>	* locks. However, lookups use shared read-lock mechanics to allow
647	>	* multiple readers in the absence of writers.  Additionally,
648	>	* these lookups do not ever block: While the lock is not
649	>	* available, they proceed along the slow traversal path (via
650	>	* next-pointers) until the lock becomes available or the list is
651	>	* exhausted, whichever comes first. (These cases are not fast,
652	>	* but maximize aggregate expected throughput.)  The AQS mechanics
653	>	* for doing this are straightforward.  The lock state is held as
654	>	* AQS getState().  Read counts are negative; the write count (1)
655	>	* is positive.  There are no signalling preferences among readers
656	>	* and writers. Since we don't need to export full Lock API, we
657	>	* just override the minimal AQS methods and use them directly.
658	>	*/
659	>	static final class TreeBin<V> extends AbstractQueuedSynchronizer {
660		private static final long serialVersionUID = 2249069246763182397L;
661	+	transient TreeNode<V> root;  // root of tree
662	+	transient TreeNode<V> first; // head of next-pointer list
663
664	<	/**
665	<	* The maximum number of times to tryLock in a prescan before
666	<	* possibly blocking on acquire in preparation for a locked
667	<	* segment operation. On multiprocessors, using a bounded
668	<	* number of retries maintains cache acquired while locating
669	<	* nodes.
670	<	*/
671	<	static final int MAX_SCAN_RETRIES =
672	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
664	>	/* AQS overrides */
665	>	public final boolean isHeldExclusively() { return getState() > 0; }
666	>	public final boolean tryAcquire(int ignore) {
667	>	if (compareAndSetState(0, 1)) {
668	>	setExclusiveOwnerThread(Thread.currentThread());
669	>	return true;
670	>	}
671	>	return false;
672	>	}
673	>	public final boolean tryRelease(int ignore) {
674	>	setExclusiveOwnerThread(null);
675	>	setState(0);
676	>	return true;
677	>	}
678	>	public final int tryAcquireShared(int ignore) {
679	>	for (int c;;) {
680	>	if ((c = getState()) > 0)
681	>	return -1;
682	>	if (compareAndSetState(c, c -1))
683	>	return 1;
684	>	}
685	>	}
686	>	public final boolean tryReleaseShared(int ignore) {
687	>	int c;
688	>	do {} while (!compareAndSetState(c = getState(), c + 1));
689	>	return c == -1;
690	>	}
691	>
692	>	/** From CLR */
693	>	private void rotateLeft(TreeNode<V> p) {
694	>	if (p != null) {
695	>	TreeNode<V> r = p.right, pp, rl;
696	>	if ((rl = p.right = r.left) != null)
697	>	rl.parent = p;
698	>	if ((pp = r.parent = p.parent) == null)
699	>	root = r;
700	>	else if (pp.left == p)
701	>	pp.left = r;
702	>	else
703	>	pp.right = r;
704	>	r.left = p;
705	>	p.parent = r;
706	>	}
707	>	}
708
709	<	/**
710	<	* The per-segment table. Elements are accessed via
711	<	* entryAt/setEntryAt providing volatile semantics.
712	<	*/
713	<	transient volatile HashEntry<K,V>[] table;
709	>	/** From CLR */
710	>	private void rotateRight(TreeNode<V> p) {
711	>	if (p != null) {
712	>	TreeNode<V> l = p.left, pp, lr;
713	>	if ((lr = p.left = l.right) != null)
714	>	lr.parent = p;
715	>	if ((pp = l.parent = p.parent) == null)
716	>	root = l;
717	>	else if (pp.right == p)
718	>	pp.right = l;
719	>	else
720	>	pp.left = l;
721	>	l.right = p;
722	>	p.parent = l;
723	>	}
724	>	}
725
726		/**
727	<	* The number of elements. Accessed only either within locks
728	<	* or among other volatile reads that maintain visibility.
727	>	* Returns the TreeNode (or null if not found) for the given key
728	>	* starting at given root.
729		*/
730	<	transient int count;
730	>	@SuppressWarnings("unchecked") final TreeNode<V> getTreeNode
731	>	(int h, Object k, TreeNode<V> p) {
732	>	Class<?> c = k.getClass();
733	>	while (p != null) {
734	>	int dir, ph;  Object pk; Class<?> pc;
735	>	if ((ph = p.hash) == h) {
736	>	if ((pk = p.key) == k || k.equals(pk))
737	>	return p;
738	>	if (c != (pc = pk.getClass()) ||
739	>	!(k instanceof Comparable) ||
740	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
741	>	if ((dir = (c == pc) ? 0 :
742	>	c.getName().compareTo(pc.getName())) == 0) {
743	>	TreeNode<V> r = null, pl, pr; // check both sides
744	>	if ((pr = p.right) != null && h >= pr.hash &&
745	>	(r = getTreeNode(h, k, pr)) != null)
746	>	return r;
747	>	else if ((pl = p.left) != null && h <= pl.hash)
748	>	dir = -1;
749	>	else // nothing there
750	>	return null;
751	>	}
752	>	}
753	>	}
754	>	else
755	>	dir = (h < ph) ? -1 : 1;
756	>	p = (dir > 0) ? p.right : p.left;
757	>	}
758	>	return null;
759	>	}
760
761		/**
762	<	* The total number of mutative operations in this segment.
763	<	* Even though this may overflows 32 bits, it provides
764	<	* sufficient accuracy for stability checks in CHM isEmpty()
307	<	* and size() methods.  Accessed only either within locks or
308	<	* among other volatile reads that maintain visibility.
762	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
763	>	* read-lock to call getTreeNode, but during failure to get
764	>	* lock, searches along next links.
765		*/
766	<	transient int modCount;
766	>	final V getValue(int h, Object k) {
767	>	Node<V> r = null;
768	>	int c = getState(); // Must read lock state first
769	>	for (Node<V> e = first; e != null; e = e.next) {
770	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
771	>	try {
772	>	r = getTreeNode(h, k, root);
773	>	} finally {
774	>	releaseShared(0);
775	>	}
776	>	break;
777	>	}
778	>	else if (e.hash == h && k.equals(e.key)) {
779	>	r = e;
780	>	break;
781	>	}
782	>	else
783	>	c = getState();
784	>	}
785	>	return r == null ? null : r.val;
786	>	}
787
788		/**
789	<	* The table is rehashed when its size exceeds this threshold.
790	<	* (The value of this field is always <tt>(int)(capacity *
315	<	* loadFactor)</tt>.)
789	>	* Finds or adds a node.
790	>	* @return null if added
791		*/
792	<	transient int threshold;
792	>	@SuppressWarnings("unchecked") final TreeNode<V> putTreeNode
793	>	(int h, Object k, V v) {
794	>	Class<?> c = k.getClass();
795	>	TreeNode<V> pp = root, p = null;
796	>	int dir = 0;
797	>	while (pp != null) { // find existing node or leaf to insert at
798	>	int ph;  Object pk; Class<?> pc;
799	>	p = pp;
800	>	if ((ph = p.hash) == h) {
801	>	if ((pk = p.key) == k || k.equals(pk))
802	>	return p;
803	>	if (c != (pc = pk.getClass()) ||
804	>	!(k instanceof Comparable) ||
805	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
806	>	TreeNode<V> s = null, r = null, pr;
807	>	if ((dir = (c == pc) ? 0 :
808	>	c.getName().compareTo(pc.getName())) == 0) {
809	>	if ((pr = p.right) != null && h >= pr.hash &&
810	>	(r = getTreeNode(h, k, pr)) != null)
811	>	return r;
812	>	else // continue left
813	>	dir = -1;
814	>	}
815	>	else if ((pr = p.right) != null && h >= pr.hash)
816	>	s = pr;
817	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
818	>	return r;
819	>	}
820	>	}
821	>	else
822	>	dir = (h < ph) ? -1 : 1;
823	>	pp = (dir > 0) ? p.right : p.left;
824	>	}
825	>
826	>	TreeNode<V> f = first;
827	>	TreeNode<V> x = first = new TreeNode<V>(h, k, v, f, p);
828	>	if (p == null)
829	>	root = x;
830	>	else { // attach and rebalance; adapted from CLR
831	>	TreeNode<V> xp, xpp;
832	>	if (f != null)
833	>	f.prev = x;
834	>	if (dir <= 0)
835	>	p.left = x;
836	>	else
837	>	p.right = x;
838	>	x.red = true;
839	>	while (x != null && (xp = x.parent) != null && xp.red &&
840	>	(xpp = xp.parent) != null) {
841	>	TreeNode<V> xppl = xpp.left;
842	>	if (xp == xppl) {
843	>	TreeNode<V> y = xpp.right;
844	>	if (y != null && y.red) {
845	>	y.red = false;
846	>	xp.red = false;
847	>	xpp.red = true;
848	>	x = xpp;
849	>	}
850	>	else {
851	>	if (x == xp.right) {
852	>	rotateLeft(x = xp);
853	>	xpp = (xp = x.parent) == null ? null : xp.parent;
854	>	}
855	>	if (xp != null) {
856	>	xp.red = false;
857	>	if (xpp != null) {
858	>	xpp.red = true;
859	>	rotateRight(xpp);
860	>	}
861	>	}
862	>	}
863	>	}
864	>	else {
865	>	TreeNode<V> y = xppl;
866	>	if (y != null && y.red) {
867	>	y.red = false;
868	>	xp.red = false;
869	>	xpp.red = true;
870	>	x = xpp;
871	>	}
872	>	else {
873	>	if (x == xp.left) {
874	>	rotateRight(x = xp);
875	>	xpp = (xp = x.parent) == null ? null : xp.parent;
876	>	}
877	>	if (xp != null) {
878	>	xp.red = false;
879	>	if (xpp != null) {
880	>	xpp.red = true;
881	>	rotateLeft(xpp);
882	>	}
883	>	}
884	>	}
885	>	}
886	>	}
887	>	TreeNode<V> r = root;
888	>	if (r != null && r.red)
889	>	r.red = false;
890	>	}
891	>	return null;
892	>	}
893
894		/**
895	<	* The load factor for the hash table.  Even though this value
896	<	* is same for all segments, it is replicated to avoid needing
897	<	* links to outer object.
898	<	* @serial
895	>	* Removes the given node, that must be present before this
896	>	* call.  This is messier than typical red-black deletion code
897	>	* because we cannot swap the contents of an interior node
898	>	* with a leaf successor that is pinned by "next" pointers
899	>	* that are accessible independently of lock. So instead we
900	>	* swap the tree linkages.
901		*/
902	<	final float loadFactor;
902	>	final void deleteTreeNode(TreeNode<V> p) {
903	>	TreeNode<V> next = (TreeNode<V>)p.next; // unlink traversal pointers
904	>	TreeNode<V> pred = p.prev;
905	>	if (pred == null)
906	>	first = next;
907	>	else
908	>	pred.next = next;
909	>	if (next != null)
910	>	next.prev = pred;
911	>	TreeNode<V> replacement;
912	>	TreeNode<V> pl = p.left;
913	>	TreeNode<V> pr = p.right;
914	>	if (pl != null && pr != null) {
915	>	TreeNode<V> s = pr, sl;
916	>	while ((sl = s.left) != null) // find successor
917	>	s = sl;
918	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
919	>	TreeNode<V> sr = s.right;
920	>	TreeNode<V> pp = p.parent;
921	>	if (s == pr) { // p was s's direct parent
922	>	p.parent = s;
923	>	s.right = p;
924	>	}
925	>	else {
926	>	TreeNode<V> sp = s.parent;
927	>	if ((p.parent = sp) != null) {
928	>	if (s == sp.left)
929	>	sp.left = p;
930	>	else
931	>	sp.right = p;
932	>	}
933	>	if ((s.right = pr) != null)
934	>	pr.parent = s;
935	>	}
936	>	p.left = null;
937	>	if ((p.right = sr) != null)
938	>	sr.parent = p;
939	>	if ((s.left = pl) != null)
940	>	pl.parent = s;
941	>	if ((s.parent = pp) == null)
942	>	root = s;
943	>	else if (p == pp.left)
944	>	pp.left = s;
945	>	else
946	>	pp.right = s;
947	>	replacement = sr;
948	>	}
949	>	else
950	>	replacement = (pl != null) ? pl : pr;
951	>	TreeNode<V> pp = p.parent;
952	>	if (replacement == null) {
953	>	if (pp == null) {
954	>	root = null;
955	>	return;
956	>	}
957	>	replacement = p;
958	>	}
959	>	else {
960	>	replacement.parent = pp;
961	>	if (pp == null)
962	>	root = replacement;
963	>	else if (p == pp.left)
964	>	pp.left = replacement;
965	>	else
966	>	pp.right = replacement;
967	>	p.left = p.right = p.parent = null;
968	>	}
969	>	if (!p.red) { // rebalance, from CLR
970	>	TreeNode<V> x = replacement;
971	>	while (x != null) {
972	>	TreeNode<V> xp, xpl;
973	>	if (x.red || (xp = x.parent) == null) {
974	>	x.red = false;
975	>	break;
976	>	}
977	>	if (x == (xpl = xp.left)) {
978	>	TreeNode<V> sib = xp.right;
979	>	if (sib != null && sib.red) {
980	>	sib.red = false;
981	>	xp.red = true;
982	>	rotateLeft(xp);
983	>	sib = (xp = x.parent) == null ? null : xp.right;
984	>	}
985	>	if (sib == null)
986	>	x = xp;
987	>	else {
988	>	TreeNode<V> sl = sib.left, sr = sib.right;
989	>	if ((sr == null || !sr.red) &&
990	>	(sl == null || !sl.red)) {
991	>	sib.red = true;
992	>	x = xp;
993	>	}
994	>	else {
995	>	if (sr == null || !sr.red) {
996	>	if (sl != null)
997	>	sl.red = false;
998	>	sib.red = true;
999	>	rotateRight(sib);
1000	>	sib = (xp = x.parent) == null ?
1001	>	null : xp.right;
1002	>	}
1003	>	if (sib != null) {
1004	>	sib.red = (xp == null) ? false : xp.red;
1005	>	if ((sr = sib.right) != null)
1006	>	sr.red = false;
1007	>	}
1008	>	if (xp != null) {
1009	>	xp.red = false;
1010	>	rotateLeft(xp);
1011	>	}
1012	>	x = root;
1013	>	}
1014	>	}
1015	>	}
1016	>	else { // symmetric
1017	>	TreeNode<V> sib = xpl;
1018	>	if (sib != null && sib.red) {
1019	>	sib.red = false;
1020	>	xp.red = true;
1021	>	rotateRight(xp);
1022	>	sib = (xp = x.parent) == null ? null : xp.left;
1023	>	}
1024	>	if (sib == null)
1025	>	x = xp;
1026	>	else {
1027	>	TreeNode<V> sl = sib.left, sr = sib.right;
1028	>	if ((sl == null || !sl.red) &&
1029	>	(sr == null || !sr.red)) {
1030	>	sib.red = true;
1031	>	x = xp;
1032	>	}
1033	>	else {
1034	>	if (sl == null || !sl.red) {
1035	>	if (sr != null)
1036	>	sr.red = false;
1037	>	sib.red = true;
1038	>	rotateLeft(sib);
1039	>	sib = (xp = x.parent) == null ?
1040	>	null : xp.left;
1041	>	}
1042	>	if (sib != null) {
1043	>	sib.red = (xp == null) ? false : xp.red;
1044	>	if ((sl = sib.left) != null)
1045	>	sl.red = false;
1046	>	}
1047	>	if (xp != null) {
1048	>	xp.red = false;
1049	>	rotateRight(xp);
1050	>	}
1051	>	x = root;
1052	>	}
1053	>	}
1054	>	}
1055	>	}
1056	>	}
1057	>	if (p == replacement && (pp = p.parent) != null) {
1058	>	if (p == pp.left) // detach pointers
1059	>	pp.left = null;
1060	>	else if (p == pp.right)
1061	>	pp.right = null;
1062	>	p.parent = null;
1063	>	}
1064	>	}
1065	>	}
1066	>
1067	>	/* ---------------- Collision reduction methods -------------- */
1068	>
1069	>	/**
1070	>	* Spreads higher bits to lower, and also forces top bit to 0.
1071	>	* Because the table uses power-of-two masking, sets of hashes
1072	>	* that vary only in bits above the current mask will always
1073	>	* collide. (Among known examples are sets of Float keys holding
1074	>	* consecutive whole numbers in small tables.)  To counter this,
1075	>	* we apply a transform that spreads the impact of higher bits
1076	>	* downward. There is a tradeoff between speed, utility, and
1077	>	* quality of bit-spreading. Because many common sets of hashes
1078	>	* are already reasonably distributed across bits (so don't benefit
1079	>	* from spreading), and because we use trees to handle large sets
1080	>	* of collisions in bins, we don't need excessively high quality.
1081	>	*/
1082	>	private static final int spread(int h) {
1083	>	h ^= (h >>> 18) ^ (h >>> 12);
1084	>	return (h ^ (h >>> 10)) & HASH_BITS;
1085	>	}
1086
1087	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
1088	<	this.loadFactor = lf;
1089	<	this.threshold = threshold;
1090	<	this.table = tab;
1087	>	/**
1088	>	* Replaces a list bin with a tree bin if key is comparable.  Call
1089	>	* only when locked.
1090	>	*/
1091	>	private final void replaceWithTreeBin(Node<V>[] tab, int index, Object key) {
1092	>	if (key instanceof Comparable) {
1093	>	TreeBin<V> t = new TreeBin<V>();
1094	>	for (Node<V> e = tabAt(tab, index); e != null; e = e.next)
1095	>	t.putTreeNode(e.hash, e.key, e.val);
1096	>	setTabAt(tab, index, new Node<V>(MOVED, t, null, null));
1097		}
1098	+	}
1099
1100	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
1101	<	HashEntry<K,V> node = tryLock() ? null :
1102	<	scanAndLockForPut(key, hash, value);
1103	<	V oldValue;
1104	<	try {
1105	<	HashEntry<K,V>[] tab = table;
1106	<	int index = (tab.length - 1) & hash;
1107	<	HashEntry<K,V> first = entryAt(tab, index);
1108	<	for (HashEntry<K,V> e = first;;) {
1109	<	if (e != null) {
1110	<	K k;
1111	<	if ((k = e.key) == key ||
1112	<	(e.hash == hash && key.equals(k))) {
1113	<	oldValue = e.value;
1114	<	if (!onlyIfAbsent) {
1115	<	e.value = value;
1116	<	++modCount;
1100	>	/* ---------------- Internal access and update methods -------------- */
1101	>
1102	>	/** Implementation for get and containsKey */
1103	>	@SuppressWarnings("unchecked") private final V internalGet(Object k) {
1104	>	int h = spread(k.hashCode());
1105	>	retry: for (Node<V>[] tab = table; tab != null;) {
1106	>	Node<V> e; Object ek; V ev; int eh; // locals to read fields once
1107	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1108	>	if ((eh = e.hash) < 0) {
1109	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1110	>	return ((TreeBin<V>)ek).getValue(h, k);
1111	>	else {                      // restart with new table
1112	>	tab = (Node<V>[])ek;
1113	>	continue retry;
1114	>	}
1115	>	}
1116	>	else if (eh == h && (ev = e.val) != null &&
1117	>	((ek = e.key) == k || k.equals(ek)))
1118	>	return ev;
1119	>	}
1120	>	break;
1121	>	}
1122	>	return null;
1123	>	}
1124	>
1125	>	/**
1126	>	* Implementation for the four public remove/replace methods:
1127	>	* Replaces node value with v, conditional upon match of cv if
1128	>	* non-null.  If resulting value is null, delete.
1129	>	*/
1130	>	@SuppressWarnings("unchecked") private final V internalReplace
1131	>	(Object k, V v, Object cv) {
1132	>	int h = spread(k.hashCode());
1133	>	V oldVal = null;
1134	>	for (Node<V>[] tab = table;;) {
1135	>	Node<V> f; int i, fh; Object fk;
1136	>	if (tab == null ||
1137	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1138	>	break;
1139	>	else if ((fh = f.hash) < 0) {
1140	>	if ((fk = f.key) instanceof TreeBin) {
1141	>	TreeBin<V> t = (TreeBin<V>)fk;
1142	>	boolean validated = false;
1143	>	boolean deleted = false;
1144	>	t.acquire(0);
1145	>	try {
1146	>	if (tabAt(tab, i) == f) {
1147	>	validated = true;
1148	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1149	>	if (p != null) {
1150	>	V pv = p.val;
1151	>	if (cv == null || cv == pv || cv.equals(pv)) {
1152	>	oldVal = pv;
1153	>	if ((p.val = v) == null) {
1154	>	deleted = true;
1155	>	t.deleteTreeNode(p);
1156	>	}
1157	>	}
1158		}
351	–	break;
1159		}
1160	<	e = e.next;
1160	>	} finally {
1161	>	t.release(0);
1162		}
1163	<	else {
1164	<	if (node != null)
1165	<	node.setNext(first);
358	<	else
359	<	node = new HashEntry<K,V>(hash, key, value, first);
360	<	int c = count + 1;
361	<	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
362	<	rehash(node);
363	<	else
364	<	setEntryAt(tab, index, node);
365	<	++modCount;
366	<	count = c;
367	<	oldValue = null;
1163	>	if (validated) {
1164	>	if (deleted)
1165	>	addCount(-1L, -1);
1166		break;
1167		}
1168		}
1169	<	} finally {
1170	<	unlock();
1169	>	else
1170	>	tab = (Node<V>[])fk;
1171	>	}
1172	>	else if (fh != h && f.next == null) // precheck
1173	>	break;                          // rules out possible existence
1174	>	else {
1175	>	boolean validated = false;
1176	>	boolean deleted = false;
1177	>	synchronized (f) {
1178	>	if (tabAt(tab, i) == f) {
1179	>	validated = true;
1180	>	for (Node<V> e = f, pred = null;;) {
1181	>	Object ek; V ev;
1182	>	if (e.hash == h &&
1183	>	((ev = e.val) != null) &&
1184	>	((ek = e.key) == k || k.equals(ek))) {
1185	>	if (cv == null || cv == ev || cv.equals(ev)) {
1186	>	oldVal = ev;
1187	>	if ((e.val = v) == null) {
1188	>	deleted = true;
1189	>	Node<V> en = e.next;
1190	>	if (pred != null)
1191	>	pred.next = en;
1192	>	else
1193	>	setTabAt(tab, i, en);
1194	>	}
1195	>	}
1196	>	break;
1197	>	}
1198	>	pred = e;
1199	>	if ((e = e.next) == null)
1200	>	break;
1201	>	}
1202	>	}
1203	>	}
1204	>	if (validated) {
1205	>	if (deleted)
1206	>	addCount(-1L, -1);
1207	>	break;
1208	>	}
1209		}
374	–	return oldValue;
1210		}
1211	+	return oldVal;
1212	+	}
1213
1214	<	/**
1215	<	* Doubles size of table and repacks entries, also adding the
1216	<	* given node to new table
1217	<	*/
1218	<	@SuppressWarnings("unchecked")
1219	<	private void rehash(HashEntry<K,V> node) {
1220	<	/*
1221	<	* Reclassify nodes in each list to new table.  Because we
1222	<	* are using power-of-two expansion, the elements from
1223	<	* each bin must either stay at same index, or move with a
1224	<	* power of two offset. We eliminate unnecessary node
1225	<	* creation by catching cases where old nodes can be
1226	<	* reused because their next fields won't change.
1227	<	* Statistically, at the default threshold, only about
1228	<	* one-sixth of them need cloning when a table
1229	<	* doubles. The nodes they replace will be garbage
1230	<	* collectable as soon as they are no longer referenced by
1231	<	* any reader thread that may be in the midst of
1232	<	* concurrently traversing table. Entry accesses use plain
1233	<	* array indexing because they are followed by volatile
1234	<	* table write.
1235	<	*/
1236	<	HashEntry<K,V>[] oldTable = table;
1237	<	int oldCapacity = oldTable.length;
1238	<	int newCapacity = oldCapacity << 1;
1239	<	threshold = (int)(newCapacity * loadFactor);
1240	<	HashEntry<K,V>[] newTable =
1241	<	(HashEntry<K,V>[]) new HashEntry<?,?>[newCapacity];
1242	<	int sizeMask = newCapacity - 1;
1243	<	for (int i = 0; i < oldCapacity ; i++) {
1244	<	HashEntry<K,V> e = oldTable[i];
1245	<	if (e != null) {
1246	<	HashEntry<K,V> next = e.next;
1247	<	int idx = e.hash & sizeMask;
1248	<	if (next == null)   //  Single node on list
1249	<	newTable[idx] = e;
1250	<	else { // Reuse consecutive sequence at same slot
1251	<	HashEntry<K,V> lastRun = e;
1252	<	int lastIdx = idx;
1253	<	for (HashEntry<K,V> last = next;
1254	<	last != null;
1255	<	last = last.next) {
1256	<	int k = last.hash & sizeMask;
1257	<	if (k != lastIdx) {
1258	<	lastIdx = k;
1259	<	lastRun = last;
1260	<	}
1261	<	}
1262	<	newTable[lastIdx] = lastRun;
1263	<	// Clone remaining nodes
1264	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1265	<	V v = p.value;
1266	<	int h = p.hash;
1267	<	int k = h & sizeMask;
1268	<	HashEntry<K,V> n = newTable[k];
1269	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
1270	<	}
1271	<	}
1272	<	}
1273	<	}
1274	<	int nodeIndex = node.hash & sizeMask; // add the new node
1275	<	node.setNext(newTable[nodeIndex]);
1276	<	newTable[nodeIndex] = node;
1277	<	table = newTable;
1278	<	}
1279	<
1280	<	/**
1281	<	* Scans for a node containing given key while trying to
1282	<	* acquire lock, creating and returning one if not found. Upon
1283	<	* return, guarantees that lock is held. Unlike in most
1284	<	* methods, calls to method equals are not screened: Since
1285	<	* traversal speed doesn't matter, we might as well help warm
1286	<	* up the associated code and accesses as well.
1287	<	*
1288	<	* @return a new node if key not found, else null
1289	<	*/
1290	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
1291	<	HashEntry<K,V> first = entryForHash(this, hash);
1292	<	HashEntry<K,V> e = first;
1293	<	HashEntry<K,V> node = null;
1294	<	int retries = -1; // negative while locating node
1295	<	while (!tryLock()) {
1296	<	HashEntry<K,V> f; // to recheck first below
1297	<	if (retries < 0) {
1298	<	if (e == null) {
462	<	if (node == null) // speculatively create node
463	<	node = new HashEntry<K,V>(hash, key, value, null);
464	<	retries = 0;
1214	>	/*
1215	>	* Internal versions of insertion methods
1216	>	* All have the same basic structure as the first (internalPut):
1217	>	*  1. If table uninitialized, create
1218	>	*  2. If bin empty, try to CAS new node
1219	>	*  3. If bin stale, use new table
1220	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1221	>	*  5. Lock and validate; if valid, scan and add or update
1222	>	*
1223	>	* The putAll method differs mainly in attempting to pre-allocate
1224	>	* enough table space, and also more lazily performs count updates
1225	>	* and checks.
1226	>	*
1227	>	* Most of the function-accepting methods can't be factored nicely
1228	>	* because they require different functional forms, so instead
1229	>	* sprawl out similar mechanics.
1230	>	*/
1231	>
1232	>	/** Implementation for put and putIfAbsent */
1233	>	@SuppressWarnings("unchecked") private final V internalPut
1234	>	(K k, V v, boolean onlyIfAbsent) {
1235	>	if (k == null || v == null) throw new NullPointerException();
1236	>	int h = spread(k.hashCode());
1237	>	int len = 0;
1238	>	for (Node<V>[] tab = table;;) {
1239	>	int i, fh; Node<V> f; Object fk; V fv;
1240	>	if (tab == null)
1241	>	tab = initTable();
1242	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1243	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null)))
1244	>	break;                   // no lock when adding to empty bin
1245	>	}
1246	>	else if ((fh = f.hash) < 0) {
1247	>	if ((fk = f.key) instanceof TreeBin) {
1248	>	TreeBin<V> t = (TreeBin<V>)fk;
1249	>	V oldVal = null;
1250	>	t.acquire(0);
1251	>	try {
1252	>	if (tabAt(tab, i) == f) {
1253	>	len = 2;
1254	>	TreeNode<V> p = t.putTreeNode(h, k, v);
1255	>	if (p != null) {
1256	>	oldVal = p.val;
1257	>	if (!onlyIfAbsent)
1258	>	p.val = v;
1259	>	}
1260	>	}
1261	>	} finally {
1262	>	t.release(0);
1263	>	}
1264	>	if (len != 0) {
1265	>	if (oldVal != null)
1266	>	return oldVal;
1267	>	break;
1268	>	}
1269	>	}
1270	>	else
1271	>	tab = (Node<V>[])fk;
1272	>	}
1273	>	else if (onlyIfAbsent && fh == h && (fv = f.val) != null &&
1274	>	((fk = f.key) == k || k.equals(fk))) // peek while nearby
1275	>	return fv;
1276	>	else {
1277	>	V oldVal = null;
1278	>	synchronized (f) {
1279	>	if (tabAt(tab, i) == f) {
1280	>	len = 1;
1281	>	for (Node<V> e = f;; ++len) {
1282	>	Object ek; V ev;
1283	>	if (e.hash == h &&
1284	>	(ev = e.val) != null &&
1285	>	((ek = e.key) == k || k.equals(ek))) {
1286	>	oldVal = ev;
1287	>	if (!onlyIfAbsent)
1288	>	e.val = v;
1289	>	break;
1290	>	}
1291	>	Node<V> last = e;
1292	>	if ((e = e.next) == null) {
1293	>	last.next = new Node<V>(h, k, v, null);
1294	>	if (len >= TREE_THRESHOLD)
1295	>	replaceWithTreeBin(tab, i, k);
1296	>	break;
1297	>	}
1298	>	}
1299		}
466	–	else if (key.equals(e.key))
467	–	retries = 0;
468	–	else
469	–	e = e.next;
1300		}
1301	<	else if (++retries > MAX_SCAN_RETRIES) {
1302	<	lock();
1301	>	if (len != 0) {
1302	>	if (oldVal != null)
1303	>	return oldVal;
1304		break;
1305		}
1306	<	else if ((retries & 1) == 0 &&
476	<	(f = entryForHash(this, hash)) != first) {
477	<	e = first = f; // re-traverse if entry changed
478	<	retries = -1;
479	<	}
480	<	}
481	<	return node;
1306	>	}
1307		}
1308	+	addCount(1L, len);
1309	+	return null;
1310	+	}
1311
1312	<	/**
1313	<	* Scans for a node containing the given key while trying to
1314	<	* acquire lock for a remove or replace operation. Upon
1315	<	* return, guarantees that lock is held.  Note that we must
1316	<	* lock even if the key is not found, to ensure sequential
1317	<	* consistency of updates.
1318	<	*/
1319	<	private void scanAndLock(Object key, int hash) {
1320	<	// similar to but simpler than scanAndLockForPut
1321	<	HashEntry<K,V> first = entryForHash(this, hash);
1322	<	HashEntry<K,V> e = first;
1323	<	int retries = -1;
1324	<	while (!tryLock()) {
1325	<	HashEntry<K,V> f;
1326	<	if (retries < 0) {
1327	<	if (e == null || key.equals(e.key))
1328	<	retries = 0;
1329	<	else
1330	<	e = e.next;
1312	>	/** Implementation for computeIfAbsent */
1313	>	@SuppressWarnings("unchecked") private final V internalComputeIfAbsent
1314	>	(K k, Function<? super K, ? extends V> mf) {
1315	>	if (k == null || mf == null)
1316	>	throw new NullPointerException();
1317	>	int h = spread(k.hashCode());
1318	>	V val = null;
1319	>	int len = 0;
1320	>	for (Node<V>[] tab = table;;) {
1321	>	Node<V> f; int i; Object fk;
1322	>	if (tab == null)
1323	>	tab = initTable();
1324	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1325	>	Node<V> node = new Node<V>(h, k, null, null);
1326	>	synchronized (node) {
1327	>	if (casTabAt(tab, i, null, node)) {
1328	>	len = 1;
1329	>	try {
1330	>	if ((val = mf.apply(k)) != null)
1331	>	node.val = val;
1332	>	} finally {
1333	>	if (val == null)
1334	>	setTabAt(tab, i, null);
1335	>	}
1336	>	}
1337		}
1338	<	else if (++retries > MAX_SCAN_RETRIES) {
505	<	lock();
1338	>	if (len != 0)
1339		break;
1340	+	}
1341	+	else if (f.hash < 0) {
1342	+	if ((fk = f.key) instanceof TreeBin) {
1343	+	TreeBin<V> t = (TreeBin<V>)fk;
1344	+	boolean added = false;
1345	+	t.acquire(0);
1346	+	try {
1347	+	if (tabAt(tab, i) == f) {
1348	+	len = 1;
1349	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1350	+	if (p != null)
1351	+	val = p.val;
1352	+	else if ((val = mf.apply(k)) != null) {
1353	+	added = true;
1354	+	len = 2;
1355	+	t.putTreeNode(h, k, val);
1356	+	}
1357	+	}
1358	+	} finally {
1359	+	t.release(0);
1360	+	}
1361	+	if (len != 0) {
1362	+	if (!added)
1363	+	return val;
1364	+	break;
1365	+	}
1366		}
1367	<	else if ((retries & 1) == 0 &&
1368	<	(f = entryForHash(this, hash)) != first) {
1369	<	e = first = f;
1370	<	retries = -1;
1367	>	else
1368	>	tab = (Node<V>[])fk;
1369	>	}
1370	>	else {
1371	>	for (Node<V> e = f; e != null; e = e.next) { // prescan
1372	>	Object ek; V ev;
1373	>	if (e.hash == h && (ev = e.val) != null &&
1374	>	((ek = e.key) == k || k.equals(ek)))
1375	>	return ev;
1376	>	}
1377	>	boolean added = false;
1378	>	synchronized (f) {
1379	>	if (tabAt(tab, i) == f) {
1380	>	len = 1;
1381	>	for (Node<V> e = f;; ++len) {
1382	>	Object ek; V ev;
1383	>	if (e.hash == h &&
1384	>	(ev = e.val) != null &&
1385	>	((ek = e.key) == k || k.equals(ek))) {
1386	>	val = ev;
1387	>	break;
1388	>	}
1389	>	Node<V> last = e;
1390	>	if ((e = e.next) == null) {
1391	>	if ((val = mf.apply(k)) != null) {
1392	>	added = true;
1393	>	last.next = new Node<V>(h, k, val, null);
1394	>	if (len >= TREE_THRESHOLD)
1395	>	replaceWithTreeBin(tab, i, k);
1396	>	}
1397	>	break;
1398	>	}
1399	>	}
1400	>	}
1401	>	}
1402	>	if (len != 0) {
1403	>	if (!added)
1404	>	return val;
1405	>	break;
1406		}
1407		}
1408		}
1409	+	if (val != null)
1410	+	addCount(1L, len);
1411	+	return val;
1412	+	}
1413
1414	<	/**
1415	<	* Remove; match on key only if value null, else match both.
1416	<	*/
1417	<	final V remove(Object key, int hash, Object value) {
1418	<	if (!tryLock())
1419	<	scanAndLock(key, hash);
1420	<	V oldValue = null;
1421	<	try {
1422	<	HashEntry<K,V>[] tab = table;
1423	<	int index = (tab.length - 1) & hash;
1424	<	HashEntry<K,V> e = entryAt(tab, index);
1425	<	HashEntry<K,V> pred = null;
1426	<	while (e != null) {
1427	<	K k;
1428	<	HashEntry<K,V> next = e.next;
1429	<	if ((k = e.key) == key ||
1430	<	(e.hash == hash && key.equals(k))) {
1431	<	V v = e.value;
1432	<	if (value == null || value == v || value.equals(v)) {
1433	<	if (pred == null)
1434	<	setEntryAt(tab, index, next);
1435	<	else
1436	<	pred.setNext(next);
1437	<	++modCount;
1438	<	--count;
1439	<	oldValue = v;
1414	>	/** Implementation for compute */
1415	>	@SuppressWarnings("unchecked") private final V internalCompute
1416	>	(K k, boolean onlyIfPresent,
1417	>	BiFunction<? super K, ? super V, ? extends V> mf) {
1418	>	if (k == null || mf == null)
1419	>	throw new NullPointerException();
1420	>	int h = spread(k.hashCode());
1421	>	V val = null;
1422	>	int delta = 0;
1423	>	int len = 0;
1424	>	for (Node<V>[] tab = table;;) {
1425	>	Node<V> f; int i, fh; Object fk;
1426	>	if (tab == null)
1427	>	tab = initTable();
1428	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1429	>	if (onlyIfPresent)
1430	>	break;
1431	>	Node<V> node = new Node<V>(h, k, null, null);
1432	>	synchronized (node) {
1433	>	if (casTabAt(tab, i, null, node)) {
1434	>	try {
1435	>	len = 1;
1436	>	if ((val = mf.apply(k, null)) != null) {
1437	>	node.val = val;
1438	>	delta = 1;
1439	>	}
1440	>	} finally {
1441	>	if (delta == 0)
1442	>	setTabAt(tab, i, null);
1443		}
1444	+	}
1445	+	}
1446	+	if (len != 0)
1447	+	break;
1448	+	}
1449	+	else if ((fh = f.hash) < 0) {
1450	+	if ((fk = f.key) instanceof TreeBin) {
1451	+	TreeBin<V> t = (TreeBin<V>)fk;
1452	+	t.acquire(0);
1453	+	try {
1454	+	if (tabAt(tab, i) == f) {
1455	+	len = 1;
1456	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1457	+	if (p == null && onlyIfPresent)
1458	+	break;
1459	+	V pv = (p == null) ? null : p.val;
1460	+	if ((val = mf.apply(k, pv)) != null) {
1461	+	if (p != null)
1462	+	p.val = val;
1463	+	else {
1464	+	len = 2;
1465	+	delta = 1;
1466	+	t.putTreeNode(h, k, val);
1467	+	}
1468	+	}
1469	+	else if (p != null) {
1470	+	delta = -1;
1471	+	t.deleteTreeNode(p);
1472	+	}
1473	+	}
1474	+	} finally {
1475	+	t.release(0);
1476	+	}
1477	+	if (len != 0)
1478		break;
1479	+	}
1480	+	else
1481	+	tab = (Node<V>[])fk;
1482	+	}
1483	+	else {
1484	+	synchronized (f) {
1485	+	if (tabAt(tab, i) == f) {
1486	+	len = 1;
1487	+	for (Node<V> e = f, pred = null;; ++len) {
1488	+	Object ek; V ev;
1489	+	if (e.hash == h &&
1490	+	(ev = e.val) != null &&
1491	+	((ek = e.key) == k || k.equals(ek))) {
1492	+	val = mf.apply(k, ev);
1493	+	if (val != null)
1494	+	e.val = val;
1495	+	else {
1496	+	delta = -1;
1497	+	Node<V> en = e.next;
1498	+	if (pred != null)
1499	+	pred.next = en;
1500	+	else
1501	+	setTabAt(tab, i, en);
1502	+	}
1503	+	break;
1504	+	}
1505	+	pred = e;
1506	+	if ((e = e.next) == null) {
1507	+	if (!onlyIfPresent &&
1508	+	(val = mf.apply(k, null)) != null) {
1509	+	pred.next = new Node<V>(h, k, val, null);
1510	+	delta = 1;
1511	+	if (len >= TREE_THRESHOLD)
1512	+	replaceWithTreeBin(tab, i, k);
1513	+	}
1514	+	break;
1515	+	}
1516	+	}
1517		}
545	–	pred = e;
546	–	e = next;
1518		}
1519	<	} finally {
1520	<	unlock();
1519	>	if (len != 0)
1520	>	break;
1521		}
551	–	return oldValue;
1522		}
1523	+	if (delta != 0)
1524	+	addCount((long)delta, len);
1525	+	return val;
1526	+	}
1527
1528	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
1529	<	if (!tryLock())
1530	<	scanAndLock(key, hash);
1531	<	boolean replaced = false;
1532	<	try {
1533	<	HashEntry<K,V> e;
1534	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1535	<	K k;
1536	<	if ((k = e.key) == key ||
1537	<	(e.hash == hash && key.equals(k))) {
1538	<	if (oldValue.equals(e.value)) {
1539	<	e.value = newValue;
1540	<	++modCount;
1541	<	replaced = true;
1528	>	/** Implementation for merge */
1529	>	@SuppressWarnings("unchecked") private final V internalMerge
1530	>	(K k, V v, BiFunction<? super V, ? super V, ? extends V> mf) {
1531	>	if (k == null || v == null || mf == null)
1532	>	throw new NullPointerException();
1533	>	int h = spread(k.hashCode());
1534	>	V val = null;
1535	>	int delta = 0;
1536	>	int len = 0;
1537	>	for (Node<V>[] tab = table;;) {
1538	>	int i; Node<V> f; Object fk; V fv;
1539	>	if (tab == null)
1540	>	tab = initTable();
1541	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1542	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1543	>	delta = 1;
1544	>	val = v;
1545	>	break;
1546	>	}
1547	>	}
1548	>	else if (f.hash < 0) {
1549	>	if ((fk = f.key) instanceof TreeBin) {
1550	>	TreeBin<V> t = (TreeBin<V>)fk;
1551	>	t.acquire(0);
1552	>	try {
1553	>	if (tabAt(tab, i) == f) {
1554	>	len = 1;
1555	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1556	>	val = (p == null) ? v : mf.apply(p.val, v);
1557	>	if (val != null) {
1558	>	if (p != null)
1559	>	p.val = val;
1560	>	else {
1561	>	len = 2;
1562	>	delta = 1;
1563	>	t.putTreeNode(h, k, val);
1564	>	}
1565	>	}
1566	>	else if (p != null) {
1567	>	delta = -1;
1568	>	t.deleteTreeNode(p);
1569	>	}
1570		}
1571	+	} finally {
1572	+	t.release(0);
1573	+	}
1574	+	if (len != 0)
1575		break;
1576	+	}
1577	+	else
1578	+	tab = (Node<V>[])fk;
1579	+	}
1580	+	else {
1581	+	synchronized (f) {
1582	+	if (tabAt(tab, i) == f) {
1583	+	len = 1;
1584	+	for (Node<V> e = f, pred = null;; ++len) {
1585	+	Object ek; V ev;
1586	+	if (e.hash == h &&
1587	+	(ev = e.val) != null &&
1588	+	((ek = e.key) == k || k.equals(ek))) {
1589	+	val = mf.apply(ev, v);
1590	+	if (val != null)
1591	+	e.val = val;
1592	+	else {
1593	+	delta = -1;
1594	+	Node<V> en = e.next;
1595	+	if (pred != null)
1596	+	pred.next = en;
1597	+	else
1598	+	setTabAt(tab, i, en);
1599	+	}
1600	+	break;
1601	+	}
1602	+	pred = e;
1603	+	if ((e = e.next) == null) {
1604	+	val = v;
1605	+	pred.next = new Node<V>(h, k, val, null);
1606	+	delta = 1;
1607	+	if (len >= TREE_THRESHOLD)
1608	+	replaceWithTreeBin(tab, i, k);
1609	+	break;
1610	+	}
1611	+	}
1612		}
1613		}
1614	<	} finally {
1615	<	unlock();
1614	>	if (len != 0)
1615	>	break;
1616		}
575	–	return replaced;
1617		}
1618	<
1619	<	final V replace(K key, int hash, V value) {
1620	<	if (!tryLock())
1621	<	scanAndLock(key, hash);
1622	<	V oldValue = null;
1623	<	try {
1624	<	HashEntry<K,V> e;
1625	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1626	<	K k;
1627	<	if ((k = e.key) == key ||
1628	<	(e.hash == hash && key.equals(k))) {
1629	<	oldValue = e.value;
1630	<	e.value = value;
1631	<	++modCount;
1632	<	break;
1618	>	if (delta != 0)
1619	>	addCount((long)delta, len);
1620	>	return val;
1621	>	}
1622	>
1623	>	/** Implementation for putAll */
1624	>	@SuppressWarnings("unchecked") private final void internalPutAll
1625	>	(Map<? extends K, ? extends V> m) {
1626	>	tryPresize(m.size());
1627	>	long delta = 0L;     // number of uncommitted additions
1628	>	boolean npe = false; // to throw exception on exit for nulls
1629	>	try {                // to clean up counts on other exceptions
1630	>	for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
1631	>	Object k; V v;
1632	>	if (entry == null || (k = entry.getKey()) == null ||
1633	>	(v = entry.getValue()) == null) {
1634	>	npe = true;
1635	>	break;
1636	>	}
1637	>	int h = spread(k.hashCode());
1638	>	for (Node<V>[] tab = table;;) {
1639	>	int i; Node<V> f; int fh; Object fk;
1640	>	if (tab == null)
1641	>	tab = initTable();
1642	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1643	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1644	>	++delta;
1645	>	break;
1646	>	}
1647	>	}
1648	>	else if ((fh = f.hash) < 0) {
1649	>	if ((fk = f.key) instanceof TreeBin) {
1650	>	TreeBin<V> t = (TreeBin<V>)fk;
1651	>	boolean validated = false;
1652	>	t.acquire(0);
1653	>	try {
1654	>	if (tabAt(tab, i) == f) {
1655	>	validated = true;
1656	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1657	>	if (p != null)
1658	>	p.val = v;
1659	>	else {
1660	>	t.putTreeNode(h, k, v);
1661	>	++delta;
1662	>	}
1663	>	}
1664	>	} finally {
1665	>	t.release(0);
1666	>	}
1667	>	if (validated)
1668	>	break;
1669	>	}
1670	>	else
1671	>	tab = (Node<V>[])fk;
1672	>	}
1673	>	else {
1674	>	int len = 0;
1675	>	synchronized (f) {
1676	>	if (tabAt(tab, i) == f) {
1677	>	len = 1;
1678	>	for (Node<V> e = f;; ++len) {
1679	>	Object ek; V ev;
1680	>	if (e.hash == h &&
1681	>	(ev = e.val) != null &&
1682	>	((ek = e.key) == k || k.equals(ek))) {
1683	>	e.val = v;
1684	>	break;
1685	>	}
1686	>	Node<V> last = e;
1687	>	if ((e = e.next) == null) {
1688	>	++delta;
1689	>	last.next = new Node<V>(h, k, v, null);
1690	>	if (len >= TREE_THRESHOLD)
1691	>	replaceWithTreeBin(tab, i, k);
1692	>	break;
1693	>	}
1694	>	}
1695	>	}
1696	>	}
1697	>	if (len != 0) {
1698	>	if (len > 1) {
1699	>	addCount(delta, len);
1700	>	delta = 0L;
1701	>	}
1702	>	break;
1703	>	}
1704		}
1705		}
594	–	} finally {
595	–	unlock();
1706		}
1707	<	return oldValue;
1707	>	} finally {
1708	>	if (delta != 0L)
1709	>	addCount(delta, 2);
1710		}
1711	+	if (npe)
1712	+	throw new NullPointerException();
1713	+	}
1714
1715	<	final void clear() {
1716	<	lock();
1717	<	try {
1718	<	HashEntry<K,V>[] tab = table;
1719	<	for (int i = 0; i < tab.length ; i++)
1720	<	setEntryAt(tab, i, null);
1721	<	++modCount;
1722	<	count = 0;
1723	<	} finally {
1724	<	unlock();
1715	>	/**
1716	>	* Implementation for clear. Steps through each bin, removing all
1717	>	* nodes.
1718	>	*/
1719	>	@SuppressWarnings("unchecked") private final void internalClear() {
1720	>	long delta = 0L; // negative number of deletions
1721	>	int i = 0;
1722	>	Node<V>[] tab = table;
1723	>	while (tab != null && i < tab.length) {
1724	>	Node<V> f = tabAt(tab, i);
1725	>	if (f == null)
1726	>	++i;
1727	>	else if (f.hash < 0) {
1728	>	Object fk;
1729	>	if ((fk = f.key) instanceof TreeBin) {
1730	>	TreeBin<V> t = (TreeBin<V>)fk;
1731	>	t.acquire(0);
1732	>	try {
1733	>	if (tabAt(tab, i) == f) {
1734	>	for (Node<V> p = t.first; p != null; p = p.next) {
1735	>	if (p.val != null) { // (currently always true)
1736	>	p.val = null;
1737	>	--delta;
1738	>	}
1739	>	}
1740	>	t.first = null;
1741	>	t.root = null;
1742	>	++i;
1743	>	}
1744	>	} finally {
1745	>	t.release(0);
1746	>	}
1747	>	}
1748	>	else
1749	>	tab = (Node<V>[])fk;
1750	>	}
1751	>	else {
1752	>	synchronized (f) {
1753	>	if (tabAt(tab, i) == f) {
1754	>	for (Node<V> e = f; e != null; e = e.next) {
1755	>	if (e.val != null) {  // (currently always true)
1756	>	e.val = null;
1757	>	--delta;
1758	>	}
1759	>	}
1760	>	setTabAt(tab, i, null);
1761	>	++i;
1762	>	}
1763	>	}
1764		}
1765		}
1766	+	if (delta != 0L)
1767	+	addCount(delta, -1);
1768		}
1769
1770	<	// Accessing segments
1770	>	/* ---------------- Table Initialization and Resizing -------------- */
1771	>
1772	>	/**
1773	>	* Returns a power of two table size for the given desired capacity.
1774	>	* See Hackers Delight, sec 3.2
1775	>	*/
1776	>	private static final int tableSizeFor(int c) {
1777	>	int n = c - 1;
1778	>	n |= n >>> 1;
1779	>	n |= n >>> 2;
1780	>	n |= n >>> 4;
1781	>	n |= n >>> 8;
1782	>	n |= n >>> 16;
1783	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1784	>	}
1785
1786		/**
1787	<	* Gets the jth element of given segment array (if nonnull) with
618	<	* volatile element access semantics via Unsafe. (The null check
619	<	* can trigger harmlessly only during deserialization.) Note:
620	<	* because each element of segments array is set only once (using
621	<	* fully ordered writes), some performance-sensitive methods rely
622	<	* on this method only as a recheck upon null reads.
1787	>	* Initializes table, using the size recorded in sizeCtl.
1788		*/
1789	<	@SuppressWarnings("unchecked")
1790	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
1791	<	long u = (j << SSHIFT) + SBASE;
1792	<	return ss == null ? null :
1793	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
1789	>	@SuppressWarnings("unchecked") private final Node<V>[] initTable() {
1790	>	Node<V>[] tab; int sc;
1791	>	while ((tab = table) == null) {
1792	>	if ((sc = sizeCtl) < 0)
1793	>	Thread.yield(); // lost initialization race; just spin
1794	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1795	>	try {
1796	>	if ((tab = table) == null) {
1797	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1798	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1799	>	table = tab = (Node<V>[])tb;
1800	>	sc = n - (n >>> 2);
1801	>	}
1802	>	} finally {
1803	>	sizeCtl = sc;
1804	>	}
1805	>	break;
1806	>	}
1807	>	}
1808	>	return tab;
1809		}
1810
1811		/**
1812	<	* Returns the segment for the given index, creating it and
1813	<	* recording in segment table (via CAS) if not already present.
1812	>	* Adds to count, and if table is too small and not already
1813	>	* resizing, initiates transfer. If already resizing, helps
1814	>	* perform transfer if work is available.  Rechecks occupancy
1815	>	* after a transfer to see if another resize is already needed
1816	>	* because resizings are lagging additions.
1817		*
1818	<	* @param k the index
1819	<	* @return the segment
1818	>	* @param x the count to add
1819	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
1820		*/
1821	<	@SuppressWarnings("unchecked")
1822	<	private Segment<K,V> ensureSegment(int k) {
1823	<	final Segment<K,V>[] ss = this.segments;
1824	<	long u = (k << SSHIFT) + SBASE; // raw offset
1825	<	Segment<K,V> seg;
1826	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
1827	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
1828	<	int cap = proto.table.length;
1829	<	float lf = proto.loadFactor;
1830	<	int threshold = (int)(cap * lf);
1831	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry<?,?>[cap];
1832	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1833	<	== null) { // recheck
1834	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
1835	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1836	<	== null) {
1837	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
1821	>	private final void addCount(long x, int check) {
1822	>	Cell[] as; long b, s;
1823	>	if ((as = counterCells) != null ||
1824	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
1825	>	Cell a; long v; int m;
1826	>	boolean uncontended = true;
1827	>	if (as == null || (m = as.length - 1) < 0 ||
1828	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
1829	>	!(uncontended =
1830	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
1831	>	fullAddCount(x, uncontended);
1832	>	return;
1833	>	}
1834	>	if (check <= 1)
1835	>	return;
1836	>	s = sumCount();
1837	>	}
1838	>	if (check >= 0) {
1839	>	Node<V>[] tab, nt; int sc;
1840	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
1841	>	tab.length < MAXIMUM_CAPACITY) {
1842	>	if (sc < 0) {
1843	>	if (sc == -1 || transferIndex <= transferOrigin ||
1844	>	(nt = nextTable) == null)
1845		break;
1846	+	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
1847	+	transfer(tab, nt);
1848		}
1849	+	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
1850	+	transfer(tab, null);
1851	+	s = sumCount();
1852		}
1853		}
659	–	return seg;
1854		}
1855
662	–	// Hash-based segment and entry accesses
663	–
1856		/**
1857	<	* Gets the segment for the given hash code.
1857	>	* Tries to presize table to accommodate the given number of elements.
1858	>	*
1859	>	* @param size number of elements (doesn't need to be perfectly accurate)
1860		*/
1861	<	@SuppressWarnings("unchecked")
1862	<	private Segment<K,V> segmentForHash(int h) {
1863	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1864	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
1861	>	@SuppressWarnings("unchecked") private final void tryPresize(int size) {
1862	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1863	>	tableSizeFor(size + (size >>> 1) + 1);
1864	>	int sc;
1865	>	while ((sc = sizeCtl) >= 0) {
1866	>	Node<V>[] tab = table; int n;
1867	>	if (tab == null || (n = tab.length) == 0) {
1868	>	n = (sc > c) ? sc : c;
1869	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1870	>	try {
1871	>	if (table == tab) {
1872	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1873	>	table = (Node<V>[])tb;
1874	>	sc = n - (n >>> 2);
1875	>	}
1876	>	} finally {
1877	>	sizeCtl = sc;
1878	>	}
1879	>	}
1880	>	}
1881	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1882	>	break;
1883	>	else if (tab == table &&
1884	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
1885	>	transfer(tab, null);
1886	>	}
1887		}
1888
1889		/**
1890	<	* Gets the table entry for the given segment and hash code.
1890	>	* Moves and/or copies the nodes in each bin to new table. See
1891	>	* above for explanation.
1892		*/
1893	<	@SuppressWarnings("unchecked")
1894	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
1895	<	HashEntry<K,V>[] tab;
1896	<	return (seg == null || (tab = seg.table) == null) ? null :
1897	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
1898	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1893	>	@SuppressWarnings("unchecked") private final void transfer
1894	>	(Node<V>[] tab, Node<V>[] nextTab) {
1895	>	int n = tab.length, stride;
1896	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
1897	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
1898	>	if (nextTab == null) {            // initiating
1899	>	try {
1900	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n << 1];
1901	>	nextTab = (Node<V>[])tb;
1902	>	} catch (Throwable ex) {      // try to cope with OOME
1903	>	sizeCtl = Integer.MAX_VALUE;
1904	>	return;
1905	>	}
1906	>	nextTable = nextTab;
1907	>	transferOrigin = n;
1908	>	transferIndex = n;
1909	>	Node<V> rev = new Node<V>(MOVED, tab, null, null);
1910	>	for (int k = n; k > 0;) {    // progressively reveal ready slots
1911	>	int nextk = (k > stride) ? k - stride : 0;
1912	>	for (int m = nextk; m < k; ++m)
1913	>	nextTab[m] = rev;
1914	>	for (int m = n + nextk; m < n + k; ++m)
1915	>	nextTab[m] = rev;
1916	>	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
1917	>	}
1918	>	}
1919	>	int nextn = nextTab.length;
1920	>	Node<V> fwd = new Node<V>(MOVED, nextTab, null, null);
1921	>	boolean advance = true;
1922	>	for (int i = 0, bound = 0;;) {
1923	>	int nextIndex, nextBound; Node<V> f; Object fk;
1924	>	while (advance) {
1925	>	if (--i >= bound)
1926	>	advance = false;
1927	>	else if ((nextIndex = transferIndex) <= transferOrigin) {
1928	>	i = -1;
1929	>	advance = false;
1930	>	}
1931	>	else if (U.compareAndSwapInt
1932	>	(this, TRANSFERINDEX, nextIndex,
1933	>	nextBound = (nextIndex > stride ?
1934	>	nextIndex - stride : 0))) {
1935	>	bound = nextBound;
1936	>	i = nextIndex - 1;
1937	>	advance = false;
1938	>	}
1939	>	}
1940	>	if (i < 0 || i >= n || i + n >= nextn) {
1941	>	for (int sc;;) {
1942	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
1943	>	if (sc == -1) {
1944	>	nextTable = null;
1945	>	table = nextTab;
1946	>	sizeCtl = (n << 1) - (n >>> 1);
1947	>	}
1948	>	return;
1949	>	}
1950	>	}
1951	>	}
1952	>	else if ((f = tabAt(tab, i)) == null) {
1953	>	if (casTabAt(tab, i, null, fwd)) {
1954	>	setTabAt(nextTab, i, null);
1955	>	setTabAt(nextTab, i + n, null);
1956	>	advance = true;
1957	>	}
1958	>	}
1959	>	else if (f.hash >= 0) {
1960	>	synchronized (f) {
1961	>	if (tabAt(tab, i) == f) {
1962	>	int runBit = f.hash & n;
1963	>	Node<V> lastRun = f, lo = null, hi = null;
1964	>	for (Node<V> p = f.next; p != null; p = p.next) {
1965	>	int b = p.hash & n;
1966	>	if (b != runBit) {
1967	>	runBit = b;
1968	>	lastRun = p;
1969	>	}
1970	>	}
1971	>	if (runBit == 0)
1972	>	lo = lastRun;
1973	>	else
1974	>	hi = lastRun;
1975	>	for (Node<V> p = f; p != lastRun; p = p.next) {
1976	>	int ph = p.hash;
1977	>	Object pk = p.key; V pv = p.val;
1978	>	if ((ph & n) == 0)
1979	>	lo = new Node<V>(ph, pk, pv, lo);
1980	>	else
1981	>	hi = new Node<V>(ph, pk, pv, hi);
1982	>	}
1983	>	setTabAt(nextTab, i, lo);
1984	>	setTabAt(nextTab, i + n, hi);
1985	>	setTabAt(tab, i, fwd);
1986	>	advance = true;
1987	>	}
1988	>	}
1989	>	}
1990	>	else if ((fk = f.key) instanceof TreeBin) {
1991	>	TreeBin<V> t = (TreeBin<V>)fk;
1992	>	t.acquire(0);
1993	>	try {
1994	>	if (tabAt(tab, i) == f) {
1995	>	TreeBin<V> lt = new TreeBin<V>();
1996	>	TreeBin<V> ht = new TreeBin<V>();
1997	>	int lc = 0, hc = 0;
1998	>	for (Node<V> e = t.first; e != null; e = e.next) {
1999	>	int h = e.hash;
2000	>	Object k = e.key; V v = e.val;
2001	>	if ((h & n) == 0) {
2002	>	++lc;
2003	>	lt.putTreeNode(h, k, v);
2004	>	}
2005	>	else {
2006	>	++hc;
2007	>	ht.putTreeNode(h, k, v);
2008	>	}
2009	>	}
2010	>	Node<V> ln, hn; // throw away trees if too small
2011	>	if (lc < TREE_THRESHOLD) {
2012	>	ln = null;
2013	>	for (Node<V> p = lt.first; p != null; p = p.next)
2014	>	ln = new Node<V>(p.hash, p.key, p.val, ln);
2015	>	}
2016	>	else
2017	>	ln = new Node<V>(MOVED, lt, null, null);
2018	>	setTabAt(nextTab, i, ln);
2019	>	if (hc < TREE_THRESHOLD) {
2020	>	hn = null;
2021	>	for (Node<V> p = ht.first; p != null; p = p.next)
2022	>	hn = new Node<V>(p.hash, p.key, p.val, hn);
2023	>	}
2024	>	else
2025	>	hn = new Node<V>(MOVED, ht, null, null);
2026	>	setTabAt(nextTab, i + n, hn);
2027	>	setTabAt(tab, i, fwd);
2028	>	advance = true;
2029	>	}
2030	>	} finally {
2031	>	t.release(0);
2032	>	}
2033	>	}
2034	>	else
2035	>	advance = true; // already processed
2036	>	}
2037		}
2038
2039	<	/* ---------------- Public operations -------------- */
2039	>	/* ---------------- Counter support -------------- */
2040	>
2041	>	final long sumCount() {
2042	>	Cell[] as = counterCells; Cell a;
2043	>	long sum = baseCount;
2044	>	if (as != null) {
2045	>	for (int i = 0; i < as.length; ++i) {
2046	>	if ((a = as[i]) != null)
2047	>	sum += a.value;
2048	>	}
2049	>	}
2050	>	return sum;
2051	>	}
2052	>
2053	>	// See LongAdder version for explanation
2054	>	private final void fullAddCount(long x, boolean wasUncontended) {
2055	>	int h;
2056	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2057	>	ThreadLocalRandom.localInit();      // force initialization
2058	>	h = ThreadLocalRandom.getProbe();
2059	>	wasUncontended = true;
2060	>	}
2061	>	boolean collide = false;                // True if last slot nonempty
2062	>	for (;;) {
2063	>	Cell[] as; Cell a; int n; long v;
2064	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2065	>	if ((a = as[(n - 1) & h]) == null) {
2066	>	if (cellsBusy == 0) {            // Try to attach new Cell
2067	>	Cell r = new Cell(x); // Optimistic create
2068	>	if (cellsBusy == 0 &&
2069	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2070	>	boolean created = false;
2071	>	try {               // Recheck under lock
2072	>	Cell[] rs; int m, j;
2073	>	if ((rs = counterCells) != null &&
2074	>	(m = rs.length) > 0 &&
2075	>	rs[j = (m - 1) & h] == null) {
2076	>	rs[j] = r;
2077	>	created = true;
2078	>	}
2079	>	} finally {
2080	>	cellsBusy = 0;
2081	>	}
2082	>	if (created)
2083	>	break;
2084	>	continue;           // Slot is now non-empty
2085	>	}
2086	>	}
2087	>	collide = false;
2088	>	}
2089	>	else if (!wasUncontended)       // CAS already known to fail
2090	>	wasUncontended = true;      // Continue after rehash
2091	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2092	>	break;
2093	>	else if (counterCells != as || n >= NCPU)
2094	>	collide = false;            // At max size or stale
2095	>	else if (!collide)
2096	>	collide = true;
2097	>	else if (cellsBusy == 0 &&
2098	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2099	>	try {
2100	>	if (counterCells == as) {// Expand table unless stale
2101	>	Cell[] rs = new Cell[n << 1];
2102	>	for (int i = 0; i < n; ++i)
2103	>	rs[i] = as[i];
2104	>	counterCells = rs;
2105	>	}
2106	>	} finally {
2107	>	cellsBusy = 0;
2108	>	}
2109	>	collide = false;
2110	>	continue;                   // Retry with expanded table
2111	>	}
2112	>	h = ThreadLocalRandom.advanceProbe(h);
2113	>	}
2114	>	else if (cellsBusy == 0 && counterCells == as &&
2115	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2116	>	boolean init = false;
2117	>	try {                           // Initialize table
2118	>	if (counterCells == as) {
2119	>	Cell[] rs = new Cell[2];
2120	>	rs[h & 1] = new Cell(x);
2121	>	counterCells = rs;
2122	>	init = true;
2123	>	}
2124	>	} finally {
2125	>	cellsBusy = 0;
2126	>	}
2127	>	if (init)
2128	>	break;
2129	>	}
2130	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2131	>	break;                          // Fall back on using base
2132	>	}
2133	>	}
2134	>
2135	>	/* ----------------Table Traversal -------------- */
2136
2137		/**
2138	<	* Creates a new, empty map with the specified initial
2139	<	* capacity, load factor and concurrency level.
2138	>	* Encapsulates traversal for methods such as containsValue; also
2139	>	* serves as a base class for other iterators and bulk tasks.
2140		*
2141	<	* @param initialCapacity the initial capacity. The implementation
2142	<	* performs internal sizing to accommodate this many elements.
2143	<	* @param loadFactor  the load factor threshold, used to control resizing.
2144	<	* Resizing may be performed when the average number of elements per
2145	<	* bin exceeds this threshold.
2146	<	* @param concurrencyLevel the estimated number of concurrently
2147	<	* updating threads. The implementation performs internal sizing
2148	<	* to try to accommodate this many threads.
2149	<	* @throws IllegalArgumentException if the initial capacity is
2150	<	* negative or the load factor or concurrencyLevel are
2151	<	* nonpositive.
2141	>	* At each step, the iterator snapshots the key ("nextKey") and
2142	>	* value ("nextVal") of a valid node (i.e., one that, at point of
2143	>	* snapshot, has a non-null user value). Because val fields can
2144	>	* change (including to null, indicating deletion), field nextVal
2145	>	* might not be accurate at point of use, but still maintains the
2146	>	* weak consistency property of holding a value that was once
2147	>	* valid. To support iterator.remove, the nextKey field is not
2148	>	* updated (nulled out) when the iterator cannot advance.
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	>	* Method advance 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	>	* Methods advanceKey and advanceValue are specializations of the
2173	>	* common cases of advance, relaying to the full version
2174	>	* otherwise. The forEachKey and forEachValue methods further
2175	>	* specialize, bypassing all incremental field updates in most cases.
2176	>	*
2177	>	* This class supports both Spliterator-based traversal and
2178	>	* CountedCompleter-based bulk tasks. The same "batch" field is
2179	>	* used, but in slightly different ways, in the two cases.  For
2180	>	* Spliterators, it is a saturating (at Integer.MAX_VALUE)
2181	>	* estimate of element coverage. For CHM tasks, it is a pre-scaled
2182	>	* size that halves down to zero for leaf tasks, that is only
2183	>	* computed upon execution of the task. (Tasks can be submitted to
2184	>	* any pool, of any size, so we don't know scale factors until
2185	>	* running.)
2186	>	*
2187	>	* This class extends CountedCompleter to streamline parallel
2188	>	* iteration in bulk operations. This adds only a few fields of
2189	>	* space overhead, which is small enough in cases where it is not
2190	>	* needed to not worry about it.  Because CountedCompleter is
2191	>	* Serializable, but iterators need not be, we need to add warning
2192	>	* suppressions.
2193	>	*/
2194	>	@SuppressWarnings("serial") static class Traverser<K,V,R>
2195	>	extends CountedCompleter<R> {
2196	>	final ConcurrentHashMap<K,V> map;
2197	>	Node<V> next;        // the next entry to use
2198	>	K nextKey;           // cached key field of next
2199	>	V nextVal;           // cached val field of next
2200	>	Node<V>[] tab;       // current table; updated if resized
2201	>	int index;           // index of bin to use next
2202	>	int baseIndex;       // current index of initial table
2203	>	int baseLimit;       // index bound for initial table
2204	>	final int baseSize;  // initial table size
2205	>	int batch;           // split control
2206	>
2207	>	/** Creates iterator for all entries in the table. */
2208	>	Traverser(ConcurrentHashMap<K,V> map) {
2209	>	this.map = map;
2210	>	Node<V>[] t = this.tab = map.table;
2211	>	baseLimit = baseSize = (t == null) ? 0 : t.length;
2212	>	}
2213	>
2214	>	/** Task constructor */
2215	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it, int batch) {
2216	>	super(it);
2217	>	this.map = map;
2218	>	this.batch = batch; // -1 if unknown
2219	>	if (it == null) {
2220	>	Node<V>[] t = this.tab = map.table;
2221	>	baseLimit = baseSize = (t == null) ? 0 : t.length;
2222	>	}
2223	>	else { // split parent
2224	>	this.tab = it.tab;
2225	>	this.baseSize = it.baseSize;
2226	>	int hi = this.baseLimit = it.baseLimit;
2227	>	it.baseLimit = this.index = this.baseIndex =
2228	>	(hi + it.baseIndex) >>> 1;
2229	>	}
2230	>	}
2231	>
2232	>	/** Spliterator constructor */
2233	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it) {
2234	>	super(it);
2235	>	this.map = map;
2236	>	if (it == null) {
2237	>	Node<V>[] t = this.tab = map.table;
2238	>	baseLimit = baseSize = (t == null) ? 0 : t.length;
2239	>	long n = map.sumCount();
2240	>	batch = ((n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2241	>	(int)n);
2242	>	}
2243	>	else {
2244	>	this.tab = it.tab;
2245	>	this.baseSize = it.baseSize;
2246	>	int hi = this.baseLimit = it.baseLimit;
2247	>	it.baseLimit = this.index = this.baseIndex =
2248	>	(hi + it.baseIndex) >>> 1;
2249	>	this.batch = it.batch >>>= 1;
2250	>	}
2251	>	}
2252	>
2253	>	/**
2254	>	* Advances if possible, returning next valid value, or null if none.
2255	>	*/
2256	>	@SuppressWarnings("unchecked") final V advance() {
2257	>	for (Node<V> e = next;;) {
2258	>	if (e != null)                  // advance past used/skipped node
2259	>	e = next = e.next;
2260	>	while (e == null) {             // get to next non-null bin
2261	>	Node<V>[] t; int i, n;      // must use locals in checks
2262	>	if (baseIndex >= baseLimit || (t = tab) == null ||
2263	>	(n = t.length) <= (i = index) || i < 0)
2264	>	return nextVal = null;
2265	>	if ((e = next = tabAt(t, index)) != null && e.hash < 0) {
2266	>	Object ek;
2267	>	if ((ek = e.key) instanceof TreeBin)
2268	>	e = ((TreeBin<V>)ek).first;
2269	>	else {
2270	>	tab = (Node<V>[])ek;
2271	>	continue;           // restarts due to null val
2272	>	}
2273	>	}
2274	>	if ((index += baseSize) >= n)
2275	>	index = ++baseIndex;    // visit upper slots if present
2276	>	}
2277	>	nextKey = (K)e.key;
2278	>	if ((nextVal = e.val) != null) // skip deleted or special nodes
2279	>	return nextVal;
2280	>	}
2281	>	}
2282	>
2283	>	/**
2284	>	* Common case version for value traversal
2285	>	*/
2286	>	@SuppressWarnings("unchecked") final V advanceValue() {
2287	>	outer: for (Node<V> e = next;;) {
2288	>	if (e == null || (e = e.next) == null) {
2289	>	Node<V>[] t; int i, len, n; Object ek;
2290	>	if ((t = tab) == null ||
2291	>	baseSize != (len = t.length) ||
2292	>	len < (n = baseLimit) ||
2293	>	baseIndex != (i = index))
2294	>	break;
2295	>	do {
2296	>	if (i < 0 || i >= n) {
2297	>	index = baseIndex = n;
2298	>	next = null;
2299	>	return nextVal = null;
2300	>	}
2301	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2302	>	if ((ek = e.key) instanceof TreeBin)
2303	>	e = ((TreeBin<V>)ek).first;
2304	>	else {
2305	>	index = baseIndex = i;
2306	>	next = null;
2307	>	tab = (Node<V>[])ek;
2308	>	break outer;
2309	>	}
2310	>	}
2311	>	++i;
2312	>	} while (e == null);
2313	>	index = baseIndex = i;
2314	>	}
2315	>	V v;
2316	>	K k = (K)e.key;
2317	>	if ((v = e.val) != null) {
2318	>	nextVal = v;
2319	>	nextKey = k;
2320	>	next = e;
2321	>	return v;
2322	>	}
2323	>	}
2324	>	return advance();
2325	>	}
2326	>
2327	>	/**
2328	>	* Common case version for key traversal
2329	>	*/
2330	>	@SuppressWarnings("unchecked") final K advanceKey() {
2331	>	outer: for (Node<V> e = next;;) {
2332	>	if (e == null || (e = e.next) == null) {
2333	>	Node<V>[] t; int i, len, n; Object ek;
2334	>	if ((t = tab) == null ||
2335	>	baseSize != (len = t.length) ||
2336	>	len < (n = baseLimit) ||
2337	>	baseIndex != (i = index))
2338	>	break;
2339	>	do {
2340	>	if (i < 0 || i >= n) {
2341	>	index = baseIndex = n;
2342	>	next = null;
2343	>	nextVal = null;
2344	>	return null;
2345	>	}
2346	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2347	>	if ((ek = e.key) instanceof TreeBin)
2348	>	e = ((TreeBin<V>)ek).first;
2349	>	else {
2350	>	index = baseIndex = i;
2351	>	next = null;
2352	>	tab = (Node<V>[])ek;
2353	>	break outer;
2354	>	}
2355	>	}
2356	>	++i;
2357	>	} while (e == null);
2358	>	index = baseIndex = i;
2359	>	}
2360	>	V v;
2361	>	K k = (K)e.key;
2362	>	if ((v = e.val) != null) {
2363	>	nextVal = v;
2364	>	nextKey = k;
2365	>	next = e;
2366	>	return k;
2367	>	}
2368	>	}
2369	>	return (advance() == null) ? null : nextKey;
2370	>	}
2371	>
2372	>	@SuppressWarnings("unchecked") final void forEachValue(Consumer<? super V> action) {
2373	>	if (action == null) throw new NullPointerException();
2374	>	Node<V>[] t; int i, len, n;
2375	>	if ((t = tab) != null && baseSize == (len = t.length) &&
2376	>	len >= (n = baseLimit) && baseIndex == (i = index)) {
2377	>	index = baseIndex = n;
2378	>	nextVal = null;
2379	>	Node<V> e = next;
2380	>	next = null;
2381	>	if (e != null)
2382	>	e = e.next;
2383	>	outer: for (;; e = e.next) {
2384	>	V v; Object ek;
2385	>	for (; e == null; ++i) {
2386	>	if (i < 0 || i >= n)
2387	>	return;
2388	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2389	>	if ((ek = e.key) instanceof TreeBin)
2390	>	e = ((TreeBin<V>)ek).first;
2391	>	else {
2392	>	index = baseIndex = i;
2393	>	tab = (Node<V>[])ek;
2394	>	break outer;
2395	>	}
2396	>	}
2397	>	}
2398	>	if ((v = e.val) != null)
2399	>	action.accept(v);
2400	>	}
2401	>	}
2402	>	V v;
2403	>	while ((v = advance()) != null)
2404	>	action.accept(v);
2405	>	}
2406	>
2407	>	@SuppressWarnings("unchecked") final void forEachKey(Consumer<? super K> action) {
2408	>	if (action == null) throw new NullPointerException();
2409	>	Node<V>[] t; int i, len, n;
2410	>	if ((t = tab) != null && baseSize == (len = t.length) &&
2411	>	len >= (n = baseLimit) && baseIndex == (i = index)) {
2412	>	index = baseIndex = n;
2413	>	nextVal = null;
2414	>	Node<V> e = next;
2415	>	next = null;
2416	>	if (e != null)
2417	>	e = e.next;
2418	>	outer: for (;; e = e.next) {
2419	>	for (; e == null; ++i) {
2420	>	if (i < 0 || i >= n)
2421	>	return;
2422	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2423	>	Object ek;
2424	>	if ((ek = e.key) instanceof TreeBin)
2425	>	e = ((TreeBin<V>)ek).first;
2426	>	else {
2427	>	index = baseIndex = i;
2428	>	tab = (Node<V>[])ek;
2429	>	break outer;
2430	>	}
2431	>	}
2432	>	}
2433	>	Object k = e.key;
2434	>	if (e.val != null)
2435	>	action.accept((K)k);
2436	>	}
2437	>	}
2438	>	while (advance() != null)
2439	>	action.accept(nextKey);
2440	>	}
2441	>
2442	>	public final void remove() {
2443	>	K k = nextKey;
2444	>	if (k == null && (advanceValue() == null || (k = nextKey) == null))
2445	>	throw new IllegalStateException();
2446	>	map.internalReplace(k, null, null);
2447	>	}
2448	>
2449	>	public final boolean hasNext() {
2450	>	return nextVal != null || advanceValue() != null;
2451	>	}
2452	>
2453	>	public final boolean hasMoreElements() { return hasNext(); }
2454	>
2455	>	public void compute() { } // default no-op CountedCompleter body
2456	>
2457	>	public long estimateSize() { return batch; }
2458	>
2459	>	/**
2460	>	* Returns a batch value > 0 if this task should (and must) be
2461	>	* split, if so, adding to pending count, and in any case
2462	>	* updating batch value. The initial batch value is approx
2463	>	* exp2 of the number of times (minus one) to split task by
2464	>	* two before executing leaf action. This value is faster to
2465	>	* compute and more convenient to use as a guide to splitting
2466	>	* than is the depth, since it is used while dividing by two
2467	>	* anyway.
2468	>	*/
2469	>	final int preSplit() {
2470	>	int b;  ForkJoinPool pool;
2471	>	if ((b = batch) < 0) { // force initialization
2472	>	int sp = (((pool = getPool()) == null) ?
2473	>	ForkJoinPool.getCommonPoolParallelism() :
2474	>	pool.getParallelism()) << 3; // slack of 8
2475	>	long n = map.sumCount();
2476	>	b = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
2477	>	}
2478	>	b = (b <= 1 || baseIndex >= baseLimit) ? 0 : (b >>> 1);
2479	>	if ((batch = b) > 0)
2480	>	addToPendingCount(1);
2481	>	return b;
2482	>	}
2483	>	}
2484	>
2485	>	/* ---------------- Public operations -------------- */
2486	>
2487	>	/**
2488	>	* Creates a new, empty map with the default initial table size (16).
2489		*/
2490	<	@SuppressWarnings("unchecked")
703	<	public ConcurrentHashMap(int initialCapacity,
704	<	float loadFactor, int concurrencyLevel) {
705	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
706	<	throw new IllegalArgumentException();
707	<	if (concurrencyLevel > MAX_SEGMENTS)
708	<	concurrencyLevel = MAX_SEGMENTS;
709	<	// Find power-of-two sizes best matching arguments
710	<	int sshift = 0;
711	<	int ssize = 1;
712	<	while (ssize < concurrencyLevel) {
713	<	++sshift;
714	<	ssize <<= 1;
715	<	}
716	<	this.segmentShift = 32 - sshift;
717	<	this.segmentMask = ssize - 1;
718	<	if (initialCapacity > MAXIMUM_CAPACITY)
719	<	initialCapacity = MAXIMUM_CAPACITY;
720	<	int c = initialCapacity / ssize;
721	<	if (c * ssize < initialCapacity)
722	<	++c;
723	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
724	<	while (cap < c)
725	<	cap <<= 1;
726	<	// create segments and segments[0]
727	<	Segment<K,V> s0 =
728	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
729	<	(HashEntry<K,V>[])new HashEntry<?,?>[cap]);
730	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment<?,?>[ssize];
731	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
732	<	this.segments = ss;
2490	>	public ConcurrentHashMap() {
2491		}
2492
2493		/**
2494	<	* Creates a new, empty map with the specified initial capacity
2495	<	* and load factor and with the default concurrencyLevel (16).
2494	>	* Creates a new, empty map with an initial table size
2495	>	* accommodating the specified number of elements without the need
2496	>	* to dynamically resize.
2497		*
2498		* @param initialCapacity The implementation performs internal
2499		* sizing to accommodate this many elements.
2500	<	* @param loadFactor  the load factor threshold, used to control resizing.
2501	<	* Resizing may be performed when the average number of elements per
2502	<	* bin exceeds this threshold.
2500	>	* @throws IllegalArgumentException if the initial capacity of
2501	>	* elements is negative
2502	>	*/
2503	>	public ConcurrentHashMap(int initialCapacity) {
2504	>	if (initialCapacity < 0)
2505	>	throw new IllegalArgumentException();
2506	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2507	>	MAXIMUM_CAPACITY :
2508	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2509	>	this.sizeCtl = cap;
2510	>	}
2511	>
2512	>	/**
2513	>	* Creates a new map with the same mappings as the given map.
2514	>	*
2515	>	* @param m the map
2516	>	*/
2517	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2518	>	this.sizeCtl = DEFAULT_CAPACITY;
2519	>	internalPutAll(m);
2520	>	}
2521	>
2522	>	/**
2523	>	* Creates a new, empty map with an initial table size based on
2524	>	* the given number of elements ({@code initialCapacity}) and
2525	>	* initial table density ({@code loadFactor}).
2526	>	*
2527	>	* @param initialCapacity the initial capacity. The implementation
2528	>	* performs internal sizing to accommodate this many elements,
2529	>	* given the specified load factor.
2530	>	* @param loadFactor the load factor (table density) for
2531	>	* establishing the initial table size
2532		* @throws IllegalArgumentException if the initial capacity of
2533		* elements is negative or the load factor is nonpositive
2534		*
2535		* @since 1.6
2536		*/
2537		public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2538	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2538	>	this(initialCapacity, loadFactor, 1);
2539		}
2540
2541		/**
2542	<	* Creates a new, empty map with the specified initial capacity,
2543	<	* and with default load factor (0.75) and concurrencyLevel (16).
2542	>	* Creates a new, empty map with an initial table size based on
2543	>	* the given number of elements ({@code initialCapacity}), table
2544	>	* density ({@code loadFactor}), and number of concurrently
2545	>	* updating threads ({@code concurrencyLevel}).
2546		*
2547		* @param initialCapacity the initial capacity. The implementation
2548	<	* performs internal sizing to accommodate this many elements.
2549	<	* @throws IllegalArgumentException if the initial capacity of
2550	<	* elements is negative.
2548	>	* performs internal sizing to accommodate this many elements,
2549	>	* given the specified load factor.
2550	>	* @param loadFactor the load factor (table density) for
2551	>	* establishing the initial table size
2552	>	* @param concurrencyLevel the estimated number of concurrently
2553	>	* updating threads. The implementation may use this value as
2554	>	* a sizing hint.
2555	>	* @throws IllegalArgumentException if the initial capacity is
2556	>	* negative or the load factor or concurrencyLevel are
2557	>	* nonpositive
2558		*/
2559	<	public ConcurrentHashMap(int initialCapacity) {
2560	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2559	>	public ConcurrentHashMap(int initialCapacity,
2560	>	float loadFactor, int concurrencyLevel) {
2561	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2562	>	throw new IllegalArgumentException();
2563	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2564	>	initialCapacity = concurrencyLevel;   // as estimated threads
2565	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2566	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2567	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
2568	>	this.sizeCtl = cap;
2569		}
2570
2571		/**
2572	<	* Creates a new, empty map with a default initial capacity (16),
2573	<	* load factor (0.75) and concurrencyLevel (16).
2572	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2573	>	* from the given type to {@code Boolean.TRUE}.
2574	>	*
2575	>	* @return the new set
2576		*/
2577	<	public ConcurrentHashMap() {
2578	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2577	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2578	>	return new KeySetView<K,Boolean>
2579	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2580		}
2581
2582		/**
2583	<	* Creates a new map with the same mappings as the given map.
2584	<	* The map is created with a capacity of 1.5 times the number
777	<	* of mappings in the given map or 16 (whichever is greater),
778	<	* and a default load factor (0.75) and concurrencyLevel (16).
2583	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2584	>	* from the given type to {@code Boolean.TRUE}.
2585		*
2586	<	* @param m the map
2586	>	* @param initialCapacity The implementation performs internal
2587	>	* sizing to accommodate this many elements.
2588	>	* @throws IllegalArgumentException if the initial capacity of
2589	>	* elements is negative
2590	>	* @return the new set
2591		*/
2592	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2593	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
2594	<	DEFAULT_INITIAL_CAPACITY),
785	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
786	<	putAll(m);
2592	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2593	>	return new KeySetView<K,Boolean>
2594	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2595		}
2596
2597		/**
2598	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
791	<	*
792	<	* @return <tt>true</tt> if this map contains no key-value mappings
2598	>	* {@inheritDoc}
2599		*/
2600		public boolean isEmpty() {
2601	<	/*
796	<	* Sum per-segment modCounts to avoid mis-reporting when
797	<	* elements are concurrently added and removed in one segment
798	<	* while checking another, in which case the table was never
799	<	* actually empty at any point. (The sum ensures accuracy up
800	<	* through at least 1<<31 per-segment modifications before
801	<	* recheck.)  Methods size() and containsValue() use similar
802	<	* constructions for stability checks.
803	<	*/
804	<	long sum = 0L;
805	<	final Segment<K,V>[] segments = this.segments;
806	<	for (int j = 0; j < segments.length; ++j) {
807	<	Segment<K,V> seg = segmentAt(segments, j);
808	<	if (seg != null) {
809	<	if (seg.count != 0)
810	<	return false;
811	<	sum += seg.modCount;
812	<	}
813	<	}
814	<	if (sum != 0L) { // recheck unless no modifications
815	<	for (int j = 0; j < segments.length; ++j) {
816	<	Segment<K,V> seg = segmentAt(segments, j);
817	<	if (seg != null) {
818	<	if (seg.count != 0)
819	<	return false;
820	<	sum -= seg.modCount;
821	<	}
822	<	}
823	<	if (sum != 0L)
824	<	return false;
825	<	}
826	<	return true;
2601	>	return sumCount() <= 0L; // ignore transient negative values
2602		}
2603
2604		/**
2605	<	* Returns the number of key-value mappings in this map.  If the
831	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
832	<	* <tt>Integer.MAX_VALUE</tt>.
833	<	*
834	<	* @return the number of key-value mappings in this map
2605	>	* {@inheritDoc}
2606		*/
2607		public int size() {
2608	<	// Try a few times to get accurate count. On failure due to
2609	<	// continuous async changes in table, resort to locking.
2610	<	final Segment<K,V>[] segments = this.segments;
2611	<	final int segmentCount = segments.length;
2612	<
842	<	long previousSum = 0L;
843	<	for (int retries = -1; retries < RETRIES_BEFORE_LOCK; retries++) {
844	<	long sum = 0L;    // sum of modCounts
845	<	long size = 0L;
846	<	for (int i = 0; i < segmentCount; i++) {
847	<	Segment<K,V> segment = segmentAt(segments, i);
848	<	if (segment != null) {
849	<	sum += segment.modCount;
850	<	size += segment.count;
851	<	}
852	<	}
853	<	if (sum == previousSum)
854	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
855	<	previousSum = sum;
856	<	}
2608	>	long n = sumCount();
2609	>	return ((n < 0L) ? 0 :
2610	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2611	>	(int)n);
2612	>	}
2613
2614	<	long size = 0L;
2615	<	for (int i = 0; i < segmentCount; i++) {
2616	<	Segment<K,V> segment = ensureSegment(i);
2617	<	segment.lock();
2618	<	size += segment.count;
2619	<	}
2620	<	for (int i = 0; i < segmentCount; i++)
2621	<	segments[i].unlock();
2622	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
2614	>	/**
2615	>	* Returns the number of mappings. This method should be used
2616	>	* instead of {@link #size} because a ConcurrentHashMap may
2617	>	* contain more mappings than can be represented as an int. The
2618	>	* value returned is an estimate; the actual count may differ if
2619	>	* there are concurrent insertions or removals.
2620	>	*
2621	>	* @return the number of mappings
2622	>	*/
2623	>	public long mappingCount() {
2624	>	long n = sumCount();
2625	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2626		}
2627
2628		/**
#	Line 877 | Line 2636 | public class ConcurrentHashMap<K, V> ext
2636		*
2637		* @throws NullPointerException if the specified key is null
2638		*/
880	–	@SuppressWarnings("unchecked")
2639		public V get(Object key) {
2640	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
2641	<	HashEntry<K,V>[] tab;
2642	<	int h = hash(key.hashCode());
2643	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2644	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
2645	<	(tab = s.table) != null) {
2646	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
2647	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2648	<	e != null; e = e.next) {
2649	<	K k;
2650	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
2651	<	return e.value;
2652	<	}
2653	<	}
2654	<	return null;
2640	>	return internalGet(key);
2641	>	}
2642	>
2643	>	/**
2644	>	* Returns the value to which the specified key is mapped,
2645	>	* or the given defaultValue if this map contains no mapping for the key.
2646	>	*
2647	>	* @param key the key
2648	>	* @param defaultValue the value to return if this map contains
2649	>	* no mapping for the given key
2650	>	* @return the mapping for the key, if present; else the defaultValue
2651	>	* @throws NullPointerException if the specified key is null
2652	>	*/
2653	>	public V getOrDefault(Object key, V defaultValue) {
2654	>	V v;
2655	>	return (v = internalGet(key)) == null ? defaultValue : v;
2656		}
2657
2658		/**
2659		* Tests if the specified object is a key in this table.
2660		*
2661	<	* @param  key   possible key
2662	<	* @return <tt>true</tt> if and only if the specified object
2661	>	* @param  key possible key
2662	>	* @return {@code true} if and only if the specified object
2663		*         is a key in this table, as determined by the
2664	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
2664	>	*         {@code equals} method; {@code false} otherwise
2665		* @throws NullPointerException if the specified key is null
2666		*/
908	–	@SuppressWarnings("unchecked")
2667		public boolean containsKey(Object key) {
2668	<	Segment<K,V> s; // same as get() except no need for volatile value read
911	<	HashEntry<K,V>[] tab;
912	<	int h = hash(key.hashCode());
913	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
914	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
915	<	(tab = s.table) != null) {
916	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
917	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
918	<	e != null; e = e.next) {
919	<	K k;
920	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
921	<	return true;
922	<	}
923	<	}
924	<	return false;
2668	>	return internalGet(key) != null;
2669		}
2670
2671		/**
2672	<	* Returns <tt>true</tt> if this map maps one or more keys to the
2673	<	* specified value. Note: This method requires a full internal
2674	<	* traversal of the hash table, and so is much slower than
931	<	* method <tt>containsKey</tt>.
2672	>	* Returns {@code true} if this map maps one or more keys to the
2673	>	* specified value. Note: This method may require a full traversal
2674	>	* of the map, and is much slower than method {@code containsKey}.
2675		*
2676		* @param value value whose presence in this map is to be tested
2677	<	* @return <tt>true</tt> if this map maps one or more keys to the
2677	>	* @return {@code true} if this map maps one or more keys to the
2678		*         specified value
2679		* @throws NullPointerException if the specified value is null
2680		*/
2681		public boolean containsValue(Object value) {
939	–	// Same idea as size()
2682		if (value == null)
2683		throw new NullPointerException();
2684	<	final Segment<K,V>[] segments = this.segments;
2685	<	long previousSum = 0L;
2686	<	int lockCount = 0;
2687	<	try {
2688	<	for (int retries = -1; ; retries++) {
947	<	long sum = 0L;    // sum of modCounts
948	<	for (int j = 0; j < segments.length; j++) {
949	<	Segment<K,V> segment;
950	<	if (retries == RETRIES_BEFORE_LOCK) {
951	<	segment = ensureSegment(j);
952	<	segment.lock();
953	<	lockCount++;
954	<	} else {
955	<	segment = segmentAt(segments, j);
956	<	if (segment == null)
957	<	continue;
958	<	}
959	<	HashEntry<K,V>[] tab = segment.table;
960	<	if (tab != null) {
961	<	for (int i = 0 ; i < tab.length; i++) {
962	<	HashEntry<K,V> e;
963	<	for (e = entryAt(tab, i); e != null; e = e.next) {
964	<	V v = e.value;
965	<	if (v != null && value.equals(v))
966	<	return true;
967	<	}
968	<	}
969	<	sum += segment.modCount;
970	<	}
971	<	}
972	<	if ((retries >= 0 && sum == previousSum) || lockCount > 0)
973	<	return false;
974	<	previousSum = sum;
975	<	}
976	<	} finally {
977	<	for (int j = 0; j < lockCount; j++)
978	<	segments[j].unlock();
2684	>	V v;
2685	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2686	>	while ((v = it.advanceValue()) != null) {
2687	>	if (v == value || value.equals(v))
2688	>	return true;
2689		}
2690	+	return false;
2691		}
2692
2693		/**
2694		* Legacy method testing if some key maps into the specified value
2695		* in this table.  This method is identical in functionality to
2696	<	* {@link #containsValue}, and exists solely to ensure
2696	>	* {@link #containsValue(Object)}, and exists solely to ensure
2697		* full compatibility with class {@link java.util.Hashtable},
2698		* which supported this method prior to introduction of the
2699		* Java Collections framework.
2700		*
2701		* @param  value a value to search for
2702	<	* @return <tt>true</tt> if and only if some key maps to the
2703	<	*         <tt>value</tt> argument in this table as
2704	<	*         determined by the <tt>equals</tt> method;
2705	<	*         <tt>false</tt> otherwise
2702	>	* @return {@code true} if and only if some key maps to the
2703	>	*         {@code value} argument in this table as
2704	>	*         determined by the {@code equals} method;
2705	>	*         {@code false} otherwise
2706		* @throws NullPointerException if the specified value is null
2707		*/
2708	<	public boolean contains(Object value) {
2708	>	@Deprecated public boolean contains(Object value) {
2709		return containsValue(value);
2710		}
2711
#	Line 1002 | Line 2713 | public class ConcurrentHashMap<K, V> ext
2713		* Maps the specified key to the specified value in this table.
2714		* Neither the key nor the value can be null.
2715		*
2716	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
2716	>	* <p>The value can be retrieved by calling the {@code get} method
2717		* with a key that is equal to the original key.
2718		*
2719		* @param key key with which the specified value is to be associated
2720		* @param value value to be associated with the specified key
2721	<	* @return the previous value associated with <tt>key</tt>, or
2722	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2721	>	* @return the previous value associated with {@code key}, or
2722	>	*         {@code null} if there was no mapping for {@code key}
2723		* @throws NullPointerException if the specified key or value is null
2724		*/
1014	–	@SuppressWarnings("unchecked")
2725		public V put(K key, V value) {
2726	<	Segment<K,V> s;
1017	<	if (value == null)
1018	<	throw new NullPointerException();
1019	<	int hash = hash(key.hashCode());
1020	<	int j = (hash >>> segmentShift) & segmentMask;
1021	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1022	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1023	<	s = ensureSegment(j);
1024	<	return s.put(key, hash, value, false);
2726	>	return internalPut(key, value, false);
2727		}
2728
2729		/**
2730		* {@inheritDoc}
2731		*
2732		* @return the previous value associated with the specified key,
2733	<	*         or <tt>null</tt> if there was no mapping for the key
2733	>	*         or {@code null} if there was no mapping for the key
2734		* @throws NullPointerException if the specified key or value is null
2735		*/
1034	–	@SuppressWarnings("unchecked")
2736		public V putIfAbsent(K key, V value) {
2737	<	Segment<K,V> s;
1037	<	if (value == null)
1038	<	throw new NullPointerException();
1039	<	int hash = hash(key.hashCode());
1040	<	int j = (hash >>> segmentShift) & segmentMask;
1041	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1042	<	(segments, (j << SSHIFT) + SBASE)) == null)
1043	<	s = ensureSegment(j);
1044	<	return s.put(key, hash, value, true);
2737	>	return internalPut(key, value, true);
2738		}
2739
2740		/**
#	Line 1052 | Line 2745 | public class ConcurrentHashMap<K, V> ext
2745		* @param m mappings to be stored in this map
2746		*/
2747		public void putAll(Map<? extends K, ? extends V> m) {
2748	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2749	<	put(e.getKey(), e.getValue());
2748	>	internalPutAll(m);
2749	>	}
2750	>
2751	>	/**
2752	>	* If the specified key is not already associated with a value (or
2753	>	* is mapped to {@code null}), attempts to compute its value using
2754	>	* the given mapping function and enters it into this map unless
2755	>	* {@code null}. The entire method invocation is performed
2756	>	* atomically, so the function is applied at most once per key.
2757	>	* Some attempted update operations on this map by other threads
2758	>	* may be blocked while computation is in progress, so the
2759	>	* computation should be short and simple, and must not attempt to
2760	>	* update any other mappings of this Map.
2761	>	*
2762	>	* @param key key with which the specified value is to be associated
2763	>	* @param mappingFunction the function to compute a value
2764	>	* @return the current (existing or computed) value associated with
2765	>	*         the specified key, or null if the computed value is null
2766	>	* @throws NullPointerException if the specified key or mappingFunction
2767	>	*         is null
2768	>	* @throws IllegalStateException if the computation detectably
2769	>	*         attempts a recursive update to this map that would
2770	>	*         otherwise never complete
2771	>	* @throws RuntimeException or Error if the mappingFunction does so,
2772	>	*         in which case the mapping is left unestablished
2773	>	*/
2774	>	public V computeIfAbsent
2775	>	(K key, Function<? super K, ? extends V> mappingFunction) {
2776	>	return internalComputeIfAbsent(key, mappingFunction);
2777	>	}
2778	>
2779	>	/**
2780	>	* If the value for the specified key is present and non-null,
2781	>	* attempts to compute a new mapping given the key and its current
2782	>	* mapped value.  The entire method invocation is performed
2783	>	* atomically.  Some attempted update operations on this map by
2784	>	* other threads may be blocked while computation is in progress,
2785	>	* so the computation should be short and simple, and must not
2786	>	* attempt to update any other mappings of this Map.
2787	>	*
2788	>	* @param key key with which a value may be associated
2789	>	* @param remappingFunction the function to compute a value
2790	>	* @return the new value associated with the specified key, or null if none
2791	>	* @throws NullPointerException if the specified key or remappingFunction
2792	>	*         is null
2793	>	* @throws IllegalStateException if the computation detectably
2794	>	*         attempts a recursive update to this map that would
2795	>	*         otherwise never complete
2796	>	* @throws RuntimeException or Error if the remappingFunction does so,
2797	>	*         in which case the mapping is unchanged
2798	>	*/
2799	>	public V computeIfPresent
2800	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2801	>	return internalCompute(key, true, remappingFunction);
2802	>	}
2803	>
2804	>	/**
2805	>	* Attempts to compute a mapping for the specified key and its
2806	>	* current mapped value (or {@code null} if there is no current
2807	>	* mapping). The entire method invocation is performed atomically.
2808	>	* Some attempted update operations on this map by other threads
2809	>	* may be blocked while computation is in progress, so the
2810	>	* computation should be short and simple, and must not attempt to
2811	>	* update any other mappings of this Map.
2812	>	*
2813	>	* @param key key with which the specified value is to be associated
2814	>	* @param remappingFunction the function to compute a value
2815	>	* @return the new value associated with the specified key, or null if none
2816	>	* @throws NullPointerException if the specified key or remappingFunction
2817	>	*         is null
2818	>	* @throws IllegalStateException if the computation detectably
2819	>	*         attempts a recursive update to this map that would
2820	>	*         otherwise never complete
2821	>	* @throws RuntimeException or Error if the remappingFunction does so,
2822	>	*         in which case the mapping is unchanged
2823	>	*/
2824	>	public V compute
2825	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2826	>	return internalCompute(key, false, remappingFunction);
2827	>	}
2828	>
2829	>	/**
2830	>	* If the specified key is not already associated with a
2831	>	* (non-null) value, associates it with the given value.
2832	>	* Otherwise, replaces the value with the results of the given
2833	>	* remapping function, or removes if {@code null}. The entire
2834	>	* method invocation is performed atomically.  Some attempted
2835	>	* update operations on this map by other threads may be blocked
2836	>	* while computation is in progress, so the computation should be
2837	>	* short and simple, and must not attempt to update any other
2838	>	* mappings of this Map.
2839	>	*
2840	>	* @param key key with which the specified value is to be associated
2841	>	* @param value the value to use if absent
2842	>	* @param remappingFunction the function to recompute a value if present
2843	>	* @return the new value associated with the specified key, or null if none
2844	>	* @throws NullPointerException if the specified key or the
2845	>	*         remappingFunction is null
2846	>	* @throws RuntimeException or Error if the remappingFunction does so,
2847	>	*         in which case the mapping is unchanged
2848	>	*/
2849	>	public V merge
2850	>	(K key, V value,
2851	>	BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2852	>	return internalMerge(key, value, remappingFunction);
2853		}
2854
2855		/**
#	Line 1061 | Line 2857 | public class ConcurrentHashMap<K, V> ext
2857		* This method does nothing if the key is not in the map.
2858		*
2859		* @param  key the key that needs to be removed
2860	<	* @return the previous value associated with <tt>key</tt>, or
2861	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2860	>	* @return the previous value associated with {@code key}, or
2861	>	*         {@code null} if there was no mapping for {@code key}
2862		* @throws NullPointerException if the specified key is null
2863		*/
2864		public V remove(Object key) {
2865	<	int hash = hash(key.hashCode());
1070	<	Segment<K,V> s = segmentForHash(hash);
1071	<	return s == null ? null : s.remove(key, hash, null);
2865	>	return internalReplace(key, null, null);
2866		}
2867
2868		/**
#	Line 1077 | Line 2871 | public class ConcurrentHashMap<K, V> ext
2871		* @throws NullPointerException if the specified key is null
2872		*/
2873		public boolean remove(Object key, Object value) {
2874	<	int hash = hash(key.hashCode());
2875	<	Segment<K,V> s;
2876	<	return value != null && (s = segmentForHash(hash)) != null &&
1083	<	s.remove(key, hash, value) != null;
2874	>	if (key == null)
2875	>	throw new NullPointerException();
2876	>	return value != null && internalReplace(key, null, value) != null;
2877		}
2878
2879		/**
#	Line 1089 | Line 2882 | public class ConcurrentHashMap<K, V> ext
2882		* @throws NullPointerException if any of the arguments are null
2883		*/
2884		public boolean replace(K key, V oldValue, V newValue) {
2885	<	int hash = hash(key.hashCode());
1093	<	if (oldValue == null || newValue == null)
2885	>	if (key == null || oldValue == null || newValue == null)
2886		throw new NullPointerException();
2887	<	Segment<K,V> s = segmentForHash(hash);
1096	<	return s != null && s.replace(key, hash, oldValue, newValue);
2887	>	return internalReplace(key, newValue, oldValue) != null;
2888		}
2889
2890		/**
2891		* {@inheritDoc}
2892		*
2893		* @return the previous value associated with the specified key,
2894	<	*         or <tt>null</tt> if there was no mapping for the key
2894	>	*         or {@code null} if there was no mapping for the key
2895		* @throws NullPointerException if the specified key or value is null
2896		*/
2897		public V replace(K key, V value) {
2898	<	int hash = hash(key.hashCode());
1108	<	if (value == null)
2898	>	if (key == null || value == null)
2899		throw new NullPointerException();
2900	<	Segment<K,V> s = segmentForHash(hash);
1111	<	return s == null ? null : s.replace(key, hash, value);
2900	>	return internalReplace(key, value, null);
2901		}
2902
2903		/**
2904		* Removes all of the mappings from this map.
2905		*/
2906		public void clear() {
2907	<	final Segment<K,V>[] segments = this.segments;
1119	<	for (int j = 0; j < segments.length; ++j) {
1120	<	Segment<K,V> s = segmentAt(segments, j);
1121	<	if (s != null)
1122	<	s.clear();
1123	<	}
2907	>	internalClear();
2908		}
2909
2910		/**
2911		* Returns a {@link Set} view of the keys contained in this map.
2912		* The set is backed by the map, so changes to the map are
2913	<	* reflected in the set, and vice-versa.  The set supports element
1130	<	* removal, which removes the corresponding mapping from this map,
1131	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1132	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1133	<	* operations.  It does not support the <tt>add</tt> or
1134	<	* <tt>addAll</tt> operations.
2913	>	* reflected in the set, and vice-versa.
2914		*
2915	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2916	<	* that will never throw {@link ConcurrentModificationException},
2917	<	* and guarantees to traverse elements as they existed upon
2918	<	* construction of the iterator, and may (but is not guaranteed to)
2919	<	* reflect any modifications subsequent to construction.
2915	>	* @return the set view
2916	>	*/
2917	>	public KeySetView<K,V> keySet() {
2918	>	KeySetView<K,V> ks = keySet;
2919	>	return (ks != null) ? ks : (keySet = new KeySetView<K,V>(this, null));
2920	>	}
2921	>
2922	>	/**
2923	>	* Returns a {@link Set} view of the keys in this map, using the
2924	>	* given common mapped value for any additions (i.e., {@link
2925	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2926	>	* This is of course only appropriate if it is acceptable to use
2927	>	* the same value for all additions from this view.
2928	>	*
2929	>	* @param mappedValue the mapped value to use for any additions
2930	>	* @return the set view
2931	>	* @throws NullPointerException if the mappedValue is null
2932		*/
2933	<	public Set<K> keySet() {
2934	<	Set<K> ks = keySet;
2935	<	return (ks != null) ? ks : (keySet = new KeySet());
2933	>	public KeySetView<K,V> keySet(V mappedValue) {
2934	>	if (mappedValue == null)
2935	>	throw new NullPointerException();
2936	>	return new KeySetView<K,V>(this, mappedValue);
2937		}
2938
2939		/**
2940		* Returns a {@link Collection} view of the values contained in this map.
2941		* The collection is backed by the map, so changes to the map are
2942	<	* reflected in the collection, and vice-versa.  The collection
1151	<	* supports element removal, which removes the corresponding
1152	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1153	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
1154	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
1155	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
2942	>	* reflected in the collection, and vice-versa.
2943		*
2944	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1158	<	* that will never throw {@link ConcurrentModificationException},
1159	<	* and guarantees to traverse elements as they existed upon
1160	<	* construction of the iterator, and may (but is not guaranteed to)
1161	<	* reflect any modifications subsequent to construction.
2944	>	* @return the collection view
2945		*/
2946	<	public Collection<V> values() {
2947	<	Collection<V> vs = values;
2948	<	return (vs != null) ? vs : (values = new Values());
2946	>	public ValuesView<K,V> values() {
2947	>	ValuesView<K,V> vs = values;
2948	>	return (vs != null) ? vs : (values = new ValuesView<K,V>(this));
2949		}
2950
2951		/**
#	Line 1170 | Line 2953 | public class ConcurrentHashMap<K, V> ext
2953		* The set is backed by the map, so changes to the map are
2954		* reflected in the set, and vice-versa.  The set supports element
2955		* removal, which removes the corresponding mapping from the map,
2956	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2957	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2958	<	* operations.  It does not support the <tt>add</tt> or
2959	<	* <tt>addAll</tt> operations.
2956	>	* via the {@code Iterator.remove}, {@code Set.remove},
2957	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2958	>	* operations.  It does not support the {@code add} or
2959	>	* {@code addAll} operations.
2960		*
2961	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2961	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2962		* that will never throw {@link ConcurrentModificationException},
2963		* and guarantees to traverse elements as they existed upon
2964		* construction of the iterator, and may (but is not guaranteed to)
2965		* reflect any modifications subsequent to construction.
2966	+	*
2967	+	* @return the set view
2968		*/
2969		public Set<Map.Entry<K,V>> entrySet() {
2970	<	Set<Map.Entry<K,V>> es = entrySet;
2971	<	return (es != null) ? es : (entrySet = new EntrySet());
2970	>	EntrySetView<K,V> es = entrySet;
2971	>	return (es != null) ? es : (entrySet = new EntrySetView<K,V>(this));
2972		}
2973
2974		/**
#	Line 1193 | Line 2978 | public class ConcurrentHashMap<K, V> ext
2978		* @see #keySet()
2979		*/
2980		public Enumeration<K> keys() {
2981	<	return new KeyIterator();
2981	>	return new KeyIterator<K,V>(this);
2982		}
2983
2984		/**
#	Line 1203 | Line 2988 | public class ConcurrentHashMap<K, V> ext
2988		* @see #values()
2989		*/
2990		public Enumeration<V> elements() {
2991	<	return new ValueIterator();
2991	>	return new ValueIterator<K,V>(this);
2992		}
2993
2994	<	/* ---------------- Iterator Support -------------- */
2995	<
2996	<	abstract class HashIterator {
2997	<	int nextSegmentIndex;
2998	<	int nextTableIndex;
2999	<	HashEntry<K,V>[] currentTable;
3000	<	HashEntry<K, V> nextEntry;
3001	<	HashEntry<K, V> lastReturned;
3002	<
3003	<	HashIterator() {
3004	<	nextSegmentIndex = segments.length - 1;
3005	<	nextTableIndex = -1;
3006	<	advance();
3007	<	}
2994	>	/**
2995	>	* Returns the hash code value for this {@link Map}, i.e.,
2996	>	* the sum of, for each key-value pair in the map,
2997	>	* {@code key.hashCode() ^ value.hashCode()}.
2998	>	*
2999	>	* @return the hash code value for this map
3000	>	*/
3001	>	public int hashCode() {
3002	>	int h = 0;
3003	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3004	>	V v;
3005	>	while ((v = it.advanceValue()) != null) {
3006	>	h += it.nextKey.hashCode() ^ v.hashCode();
3007	>	}
3008	>	return h;
3009	>	}
3010
3011	<	/**
3012	<	* Sets nextEntry to first node of next non-empty table
3013	<	* (in backwards order, to simplify checks).
3014	<	*/
3015	<	final void advance() {
3011	>	/**
3012	>	* Returns a string representation of this map.  The string
3013	>	* representation consists of a list of key-value mappings (in no
3014	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
3015	>	* mappings are separated by the characters {@code ", "} (comma
3016	>	* and space).  Each key-value mapping is rendered as the key
3017	>	* followed by an equals sign ("{@code =}") followed by the
3018	>	* associated value.
3019	>	*
3020	>	* @return a string representation of this map
3021	>	*/
3022	>	public String toString() {
3023	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3024	>	StringBuilder sb = new StringBuilder();
3025	>	sb.append('{');
3026	>	V v;
3027	>	if ((v = it.advanceValue()) != null) {
3028		for (;;) {
3029	<	if (nextTableIndex >= 0) {
3030	<	if ((nextEntry = entryAt(currentTable,
3031	<	nextTableIndex--)) != null)
3032	<	break;
3033	<	}
1235	<	else if (nextSegmentIndex >= 0) {
1236	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
1237	<	if (seg != null && (currentTable = seg.table) != null)
1238	<	nextTableIndex = currentTable.length - 1;
1239	<	}
1240	<	else
3029	>	K k = it.nextKey;
3030	>	sb.append(k == this ? "(this Map)" : k);
3031	>	sb.append('=');
3032	>	sb.append(v == this ? "(this Map)" : v);
3033	>	if ((v = it.advanceValue()) == null)
3034		break;
3035	+	sb.append(',').append(' ');
3036		}
3037		}
3038	+	return sb.append('}').toString();
3039	+	}
3040
3041	<	final HashEntry<K,V> nextEntry() {
3042	<	HashEntry<K,V> e = nextEntry;
3043	<	if (e == null)
3041	>	/**
3042	>	* Compares the specified object with this map for equality.
3043	>	* Returns {@code true} if the given object is a map with the same
3044	>	* mappings as this map.  This operation may return misleading
3045	>	* results if either map is concurrently modified during execution
3046	>	* of this method.
3047	>	*
3048	>	* @param o object to be compared for equality with this map
3049	>	* @return {@code true} if the specified object is equal to this map
3050	>	*/
3051	>	public boolean equals(Object o) {
3052	>	if (o != this) {
3053	>	if (!(o instanceof Map))
3054	>	return false;
3055	>	Map<?,?> m = (Map<?,?>) o;
3056	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3057	>	V val;
3058	>	while ((val = it.advanceValue()) != null) {
3059	>	Object v = m.get(it.nextKey);
3060	>	if (v == null || (v != val && !v.equals(val)))
3061	>	return false;
3062	>	}
3063	>	for (Map.Entry<?,?> e : m.entrySet()) {
3064	>	Object mk, mv, v;
3065	>	if ((mk = e.getKey()) == null ||
3066	>	(mv = e.getValue()) == null ||
3067	>	(v = internalGet(mk)) == null ||
3068	>	(mv != v && !mv.equals(v)))
3069	>	return false;
3070	>	}
3071	>	}
3072	>	return true;
3073	>	}
3074	>
3075	>	/* ----------------Iterators -------------- */
3076	>
3077	>	@SuppressWarnings("serial") static final class KeyIterator<K,V>
3078	>	extends Traverser<K,V,Object>
3079	>	implements Spliterator<K>, Iterator<K>, Enumeration<K> {
3080	>	KeyIterator(ConcurrentHashMap<K,V> map) { super(map); }
3081	>	KeyIterator(ConcurrentHashMap<K,V> map, Traverser<K,V,Object> it) {
3082	>	super(map, it);
3083	>	}
3084	>	public Spliterator<K> trySplit() {
3085	>	return (baseLimit - baseIndex <= 1) ? null :
3086	>	new KeyIterator<K,V>(map, this);
3087	>	}
3088	>	public final K next() {
3089	>	K k;
3090	>	if ((k = (nextVal == null) ? advanceKey() : nextKey) == null)
3091		throw new NoSuchElementException();
3092	<	lastReturned = e; // cannot assign until after null check
3093	<	if ((nextEntry = e.next) == null)
1251	<	advance();
1252	<	return e;
3092	>	nextVal = null;
3093	>	return k;
3094		}
3095
3096	<	public final boolean hasNext() { return nextEntry != null; }
1256	<	public final boolean hasMoreElements() { return nextEntry != null; }
3096	>	public final K nextElement() { return next(); }
3097
3098	<	public final void remove() {
3099	<	if (lastReturned == null)
3100	<	throw new IllegalStateException();
3101	<	ConcurrentHashMap.this.remove(lastReturned.key);
1262	<	lastReturned = null;
3098	>	public Iterator<K> iterator() { return this; }
3099	>
3100	>	public void forEachRemaining(Consumer<? super K> action) {
3101	>	forEachKey(action);
3102		}
3103	+
3104	+	public boolean tryAdvance(Consumer<? super K> block) {
3105	+	if (block == null) throw new NullPointerException();
3106	+	K k;
3107	+	if ((k = advanceKey()) == null)
3108	+	return false;
3109	+	block.accept(k);
3110	+	return true;
3111	+	}
3112	+
3113	+	public int characteristics() {
3114	+	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3115	+	Spliterator.NONNULL;
3116	+	}
3117	+
3118		}
3119
3120	<	final class KeyIterator
3121	<	extends HashIterator
3122	<	implements Iterator<K>, Enumeration<K>
3123	<	{
3124	<	public final K next()        { return super.nextEntry().key; }
3125	<	public final K nextElement() { return super.nextEntry().key; }
3120	>	@SuppressWarnings("serial") static final class ValueIterator<K,V>
3121	>	extends Traverser<K,V,Object>
3122	>	implements Spliterator<V>, Iterator<V>, Enumeration<V> {
3123	>	ValueIterator(ConcurrentHashMap<K,V> map) { super(map); }
3124	>	ValueIterator(ConcurrentHashMap<K,V> map, Traverser<K,V,Object> it) {
3125	>	super(map, it);
3126	>	}
3127	>	public Spliterator<V> trySplit() {
3128	>	return (baseLimit - baseIndex <= 1) ? null :
3129	>	new ValueIterator<K,V>(map, this);
3130	>	}
3131	>
3132	>	public final V next() {
3133	>	V v;
3134	>	if ((v = nextVal) == null && (v = advanceValue()) == null)
3135	>	throw new NoSuchElementException();
3136	>	nextVal = null;
3137	>	return v;
3138	>	}
3139	>
3140	>	public final V nextElement() { return next(); }
3141	>
3142	>	public Iterator<V> iterator() { return this; }
3143	>
3144	>	public void forEachRemaining(Consumer<? super V> action) {
3145	>	forEachValue(action);
3146	>	}
3147	>
3148	>	public boolean tryAdvance(Consumer<? super V> block) {
3149	>	V v;
3150	>	if (block == null) throw new NullPointerException();
3151	>	if ((v = advanceValue()) == null)
3152	>	return false;
3153	>	block.accept(v);
3154	>	return true;
3155	>	}
3156	>
3157	>	public int characteristics() {
3158	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3159	>	}
3160		}
3161
3162	<	final class ValueIterator
3163	<	extends HashIterator
3164	<	implements Iterator<V>, Enumeration<V>
3165	<	{
3166	<	public final V next()        { return super.nextEntry().value; }
3167	<	public final V nextElement() { return super.nextEntry().value; }
3162	>	@SuppressWarnings("serial") static final class EntryIterator<K,V>
3163	>	extends Traverser<K,V,Object>
3164	>	implements Spliterator<Map.Entry<K,V>>, Iterator<Map.Entry<K,V>> {
3165	>	EntryIterator(ConcurrentHashMap<K,V> map) { super(map); }
3166	>	EntryIterator(ConcurrentHashMap<K,V> map, Traverser<K,V,Object> it) {
3167	>	super(map, it);
3168	>	}
3169	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3170	>	return (baseLimit - baseIndex <= 1) ? null :
3171	>	new EntryIterator<K,V>(map, this);
3172	>	}
3173	>
3174	>	public final Map.Entry<K,V> next() {
3175	>	V v;
3176	>	if ((v = nextVal) == null && (v = advanceValue()) == null)
3177	>	throw new NoSuchElementException();
3178	>	K k = nextKey;
3179	>	nextVal = null;
3180	>	return new MapEntry<K,V>(k, v, map);
3181	>	}
3182	>
3183	>	public Iterator<Map.Entry<K,V>> iterator() { return this; }
3184	>
3185	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3186	>	if (action == null) throw new NullPointerException();
3187	>	V v;
3188	>	while ((v = advanceValue()) != null)
3189	>	action.accept(entryFor(nextKey, v));
3190	>	}
3191	>
3192	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> block) {
3193	>	V v;
3194	>	if (block == null) throw new NullPointerException();
3195	>	if ((v = advanceValue()) == null)
3196	>	return false;
3197	>	block.accept(entryFor(nextKey, v));
3198	>	return true;
3199	>	}
3200	>
3201	>	public int characteristics() {
3202	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3203	>	Spliterator.NONNULL;
3204	>	}
3205		}
3206
3207		/**
3208	<	* Custom Entry class used by EntryIterator.next(), that relays
1284	<	* setValue changes to the underlying map.
3208	>	* Exported Entry for iterators
3209		*/
3210	<	final class WriteThroughEntry
3211	<	extends AbstractMap.SimpleEntry<K,V>
3212	<	{
3213	<	static final long serialVersionUID = 7249069246763182397L;
3214	<
3215	<	WriteThroughEntry(K k, V v) {
3216	<	super(k,v);
3210	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3211	>	final K key; // non-null
3212	>	V val;       // non-null
3213	>	final ConcurrentHashMap<K,V> map;
3214	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3215	>	this.key = key;
3216	>	this.val = val;
3217	>	this.map = map;
3218	>	}
3219	>	public final K getKey()       { return key; }
3220	>	public final V getValue()     { return val; }
3221	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3222	>	public final String toString(){ return key + "=" + val; }
3223	>
3224	>	public final boolean equals(Object o) {
3225	>	Object k, v; Map.Entry<?,?> e;
3226	>	return ((o instanceof Map.Entry) &&
3227	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3228	>	(v = e.getValue()) != null &&
3229	>	(k == key || k.equals(key)) &&
3230	>	(v == val || v.equals(val)));
3231		}
3232
3233		/**
3234		* Sets our entry's value and writes through to the map. The
3235	<	* value to return is somewhat arbitrary here. Since a
3236	<	* WriteThroughEntry does not necessarily track asynchronous
3237	<	* changes, the most recent "previous" value could be
3238	<	* different from what we return (or could even have been
3239	<	* removed in which case the put will re-establish). We do not
1302	<	* and cannot guarantee more.
3235	>	* value to return is somewhat arbitrary here. Since we do not
3236	>	* necessarily track asynchronous changes, the most recent
3237	>	* "previous" value could be different from what we return (or
3238	>	* could even have been removed in which case the put will
3239	>	* re-establish). We do not and cannot guarantee more.
3240		*/
3241	<	public V setValue(V value) {
3241	>	public final V setValue(V value) {
3242		if (value == null) throw new NullPointerException();
3243	<	V v = super.setValue(value);
3244	<	ConcurrentHashMap.this.put(getKey(), value);
3243	>	V v = val;
3244	>	val = value;
3245	>	map.put(key, value);
3246		return v;
3247		}
3248		}
3249
3250	<	final class EntryIterator
3251	<	extends HashIterator
3252	<	implements Iterator<Entry<K,V>>
3253	<	{
3254	<	public Map.Entry<K,V> next() {
3255	<	HashEntry<K,V> e = super.nextEntry();
1318	<	return new WriteThroughEntry(e.key, e.value);
1319	<	}
3250	>	/**
3251	>	* Returns exportable snapshot entry for the given key and value
3252	>	* when write-through can't or shouldn't be used.
3253	>	*/
3254	>	static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
3255	>	return new AbstractMap.SimpleEntry<K,V>(k, v);
3256		}
3257
3258	<	final class KeySet extends AbstractSet<K> {
3259	<	public Iterator<K> iterator() {
3260	<	return new KeyIterator();
3258	>	/* ---------------- Serialization Support -------------- */
3259	>
3260	>	/**
3261	>	* Stripped-down version of helper class used in previous version,
3262	>	* declared for the sake of serialization compatibility
3263	>	*/
3264	>	static class Segment<K,V> implements Serializable {
3265	>	private static final long serialVersionUID = 2249069246763182397L;
3266	>	final float loadFactor;
3267	>	Segment(float lf) { this.loadFactor = lf; }
3268	>	}
3269	>
3270	>	/**
3271	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
3272	>	* stream (i.e., serializes it).
3273	>	* @param s the stream
3274	>	* @serialData
3275	>	* the key (Object) and value (Object)
3276	>	* for each key-value mapping, followed by a null pair.
3277	>	* The key-value mappings are emitted in no particular order.
3278	>	*/
3279	>	@SuppressWarnings("unchecked") private void writeObject
3280	>	(java.io.ObjectOutputStream s)
3281	>	throws java.io.IOException {
3282	>	if (segments == null) { // for serialization compatibility
3283	>	segments = (Segment<K,V>[])
3284	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3285	>	for (int i = 0; i < segments.length; ++i)
3286	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3287		}
3288	<	public int size() {
3289	<	return ConcurrentHashMap.this.size();
3288	>	s.defaultWriteObject();
3289	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3290	>	V v;
3291	>	while ((v = it.advanceValue()) != null) {
3292	>	s.writeObject(it.nextKey);
3293	>	s.writeObject(v);
3294		}
3295	<	public boolean isEmpty() {
3296	<	return ConcurrentHashMap.this.isEmpty();
3295	>	s.writeObject(null);
3296	>	s.writeObject(null);
3297	>	segments = null; // throw away
3298	>	}
3299	>
3300	>	/**
3301	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3302	>	* @param s the stream
3303	>	*/
3304	>	@SuppressWarnings("unchecked") private void readObject
3305	>	(java.io.ObjectInputStream s)
3306	>	throws java.io.IOException, ClassNotFoundException {
3307	>	s.defaultReadObject();
3308	>	this.segments = null; // unneeded
3309	>
3310	>	// Create all nodes, then place in table once size is known
3311	>	long size = 0L;
3312	>	Node<V> p = null;
3313	>	for (;;) {
3314	>	K k = (K) s.readObject();
3315	>	V v = (V) s.readObject();
3316	>	if (k != null && v != null) {
3317	>	int h = spread(k.hashCode());
3318	>	p = new Node<V>(h, k, v, p);
3319	>	++size;
3320	>	}
3321	>	else
3322	>	break;
3323		}
3324	<	public boolean contains(Object o) {
3325	<	return ConcurrentHashMap.this.containsKey(o);
3324	>	if (p != null) {
3325	>	boolean init = false;
3326	>	int n;
3327	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3328	>	n = MAXIMUM_CAPACITY;
3329	>	else {
3330	>	int sz = (int)size;
3331	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3332	>	}
3333	>	int sc = sizeCtl;
3334	>	boolean collide = false;
3335	>	if (n > sc &&
3336	>	U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
3337	>	try {
3338	>	if (table == null) {
3339	>	init = true;
3340	>	@SuppressWarnings("rawtypes") Node[] rt = new Node[n];
3341	>	Node<V>[] tab = (Node<V>[])rt;
3342	>	int mask = n - 1;
3343	>	while (p != null) {
3344	>	int j = p.hash & mask;
3345	>	Node<V> next = p.next;
3346	>	Node<V> q = p.next = tabAt(tab, j);
3347	>	setTabAt(tab, j, p);
3348	>	if (!collide && q != null && q.hash == p.hash)
3349	>	collide = true;
3350	>	p = next;
3351	>	}
3352	>	table = tab;
3353	>	addCount(size, -1);
3354	>	sc = n - (n >>> 2);
3355	>	}
3356	>	} finally {
3357	>	sizeCtl = sc;
3358	>	}
3359	>	if (collide) { // rescan and convert to TreeBins
3360	>	Node<V>[] tab = table;
3361	>	for (int i = 0; i < tab.length; ++i) {
3362	>	int c = 0;
3363	>	for (Node<V> e = tabAt(tab, i); e != null; e = e.next) {
3364	>	if (++c > TREE_THRESHOLD &&
3365	>	(e.key instanceof Comparable)) {
3366	>	replaceWithTreeBin(tab, i, e.key);
3367	>	break;
3368	>	}
3369	>	}
3370	>	}
3371	>	}
3372	>	}
3373	>	if (!init) { // Can only happen if unsafely published.
3374	>	while (p != null) {
3375	>	internalPut((K)p.key, p.val, false);
3376	>	p = p.next;
3377	>	}
3378	>	}
3379		}
3380	<	public boolean remove(Object o) {
3381	<	return ConcurrentHashMap.this.remove(o) != null;
3380	>	}
3381	>
3382	>	// -------------------------------------------------------
3383	>
3384	>	// Sequential bulk operations
3385	>
3386	>	/**
3387	>	* Performs the given action for each (key, value).
3388	>	*
3389	>	* @param action the action
3390	>	*/
3391	>	public void forEachSequentially
3392	>	(BiConsumer<? super K, ? super V> action) {
3393	>	if (action == null) throw new NullPointerException();
3394	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3395	>	V v;
3396	>	while ((v = it.advanceValue()) != null)
3397	>	action.accept(it.nextKey, v);
3398	>	}
3399	>
3400	>	/**
3401	>	* Performs the given action for each non-null transformation
3402	>	* of each (key, value).
3403	>	*
3404	>	* @param transformer a function returning the transformation
3405	>	* for an element, or null if there is no transformation (in
3406	>	* which case the action is not applied)
3407	>	* @param action the action
3408	>	*/
3409	>	public <U> void forEachSequentially
3410	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3411	>	Consumer<? super U> action) {
3412	>	if (transformer == null || action == null)
3413	>	throw new NullPointerException();
3414	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3415	>	V v; U u;
3416	>	while ((v = it.advanceValue()) != null) {
3417	>	if ((u = transformer.apply(it.nextKey, v)) != null)
3418	>	action.accept(u);
3419		}
3420	<	public void clear() {
3421	<	ConcurrentHashMap.this.clear();
3420	>	}
3421	>
3422	>	/**
3423	>	* Returns a non-null result from applying the given search
3424	>	* function on each (key, value), or null if none.
3425	>	*
3426	>	* @param searchFunction a function returning a non-null
3427	>	* result on success, else null
3428	>	* @return a non-null result from applying the given search
3429	>	* function on each (key, value), or null if none
3430	>	*/
3431	>	public <U> U searchSequentially
3432	>	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3433	>	if (searchFunction == null) throw new NullPointerException();
3434	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3435	>	V v; U u;
3436	>	while ((v = it.advanceValue()) != null) {
3437	>	if ((u = searchFunction.apply(it.nextKey, v)) != null)
3438	>	return u;
3439		}
3440	+	return null;
3441		}
3442
3443	<	final class Values extends AbstractCollection<V> {
3444	<	public Iterator<V> iterator() {
3445	<	return new ValueIterator();
3443	>	/**
3444	>	* Returns the result of accumulating the given transformation
3445	>	* of all (key, value) pairs using the given reducer to
3446	>	* combine values, or null if none.
3447	>	*
3448	>	* @param transformer a function returning the transformation
3449	>	* for an element, or null if there is no transformation (in
3450	>	* which case it is not combined)
3451	>	* @param reducer a commutative associative combining function
3452	>	* @return the result of accumulating the given transformation
3453	>	* of all (key, value) pairs
3454	>	*/
3455	>	public <U> U reduceSequentially
3456	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3457	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3458	>	if (transformer == null || reducer == null)
3459	>	throw new NullPointerException();
3460	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3461	>	U r = null, u; V v;
3462	>	while ((v = it.advanceValue()) != null) {
3463	>	if ((u = transformer.apply(it.nextKey, v)) != null)
3464	>	r = (r == null) ? u : reducer.apply(r, u);
3465		}
3466	<	public int size() {
3467	<	return ConcurrentHashMap.this.size();
3466	>	return r;
3467	>	}
3468	>
3469	>	/**
3470	>	* Returns the result of accumulating the given transformation
3471	>	* of all (key, value) pairs using the given reducer to
3472	>	* combine values, and the given basis as an identity value.
3473	>	*
3474	>	* @param transformer a function returning the transformation
3475	>	* for an element
3476	>	* @param basis the identity (initial default value) for the reduction
3477	>	* @param reducer a commutative associative combining function
3478	>	* @return the result of accumulating the given transformation
3479	>	* of all (key, value) pairs
3480	>	*/
3481	>	public double reduceToDoubleSequentially
3482	>	(ToDoubleBiFunction<? super K, ? super V> transformer,
3483	>	double basis,
3484	>	DoubleBinaryOperator reducer) {
3485	>	if (transformer == null || reducer == null)
3486	>	throw new NullPointerException();
3487	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3488	>	double r = basis; V v;
3489	>	while ((v = it.advanceValue()) != null)
3490	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(it.nextKey, v));
3491	>	return r;
3492	>	}
3493	>
3494	>	/**
3495	>	* Returns the result of accumulating the given transformation
3496	>	* of all (key, value) pairs using the given reducer to
3497	>	* combine values, and the given basis as an identity value.
3498	>	*
3499	>	* @param transformer a function returning the transformation
3500	>	* for an element
3501	>	* @param basis the identity (initial default value) for the reduction
3502	>	* @param reducer a commutative associative combining function
3503	>	* @return the result of accumulating the given transformation
3504	>	* of all (key, value) pairs
3505	>	*/
3506	>	public long reduceToLongSequentially
3507	>	(ToLongBiFunction<? super K, ? super V> transformer,
3508	>	long basis,
3509	>	LongBinaryOperator reducer) {
3510	>	if (transformer == null || reducer == null)
3511	>	throw new NullPointerException();
3512	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3513	>	long r = basis; V v;
3514	>	while ((v = it.advanceValue()) != null)
3515	>	r = reducer.applyAsLong(r, transformer.applyAsLong(it.nextKey, v));
3516	>	return r;
3517	>	}
3518	>
3519	>	/**
3520	>	* Returns the result of accumulating the given transformation
3521	>	* of all (key, value) pairs using the given reducer to
3522	>	* combine values, and the given basis as an identity value.
3523	>	*
3524	>	* @param transformer a function returning the transformation
3525	>	* for an element
3526	>	* @param basis the identity (initial default value) for the reduction
3527	>	* @param reducer a commutative associative combining function
3528	>	* @return the result of accumulating the given transformation
3529	>	* of all (key, value) pairs
3530	>	*/
3531	>	public int reduceToIntSequentially
3532	>	(ToIntBiFunction<? super K, ? super V> transformer,
3533	>	int basis,
3534	>	IntBinaryOperator reducer) {
3535	>	if (transformer == null || reducer == null)
3536	>	throw new NullPointerException();
3537	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3538	>	int r = basis; V v;
3539	>	while ((v = it.advanceValue()) != null)
3540	>	r = reducer.applyAsInt(r, transformer.applyAsInt(it.nextKey, v));
3541	>	return r;
3542	>	}
3543	>
3544	>	/**
3545	>	* Performs the given action for each key.
3546	>	*
3547	>	* @param action the action
3548	>	*/
3549	>	public void forEachKeySequentially
3550	>	(Consumer<? super K> action) {
3551	>	new Traverser<K,V,Object>(this).forEachKey(action);
3552	>	}
3553	>
3554	>	/**
3555	>	* Performs the given action for each non-null transformation
3556	>	* of each key.
3557	>	*
3558	>	* @param transformer a function returning the transformation
3559	>	* for an element, or null if there is no transformation (in
3560	>	* which case the action is not applied)
3561	>	* @param action the action
3562	>	*/
3563	>	public <U> void forEachKeySequentially
3564	>	(Function<? super K, ? extends U> transformer,
3565	>	Consumer<? super U> action) {
3566	>	if (transformer == null || action == null)
3567	>	throw new NullPointerException();
3568	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3569	>	K k; U u;
3570	>	while ((k = it.advanceKey()) != null) {
3571	>	if ((u = transformer.apply(k)) != null)
3572	>	action.accept(u);
3573		}
3574	<	public boolean isEmpty() {
3575	<	return ConcurrentHashMap.this.isEmpty();
3574	>	}
3575	>
3576	>	/**
3577	>	* Returns a non-null result from applying the given search
3578	>	* function on each key, or null if none.
3579	>	*
3580	>	* @param searchFunction a function returning a non-null
3581	>	* result on success, else null
3582	>	* @return a non-null result from applying the given search
3583	>	* function on each key, or null if none
3584	>	*/
3585	>	public <U> U searchKeysSequentially
3586	>	(Function<? super K, ? extends U> searchFunction) {
3587	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3588	>	K k; U u;
3589	>	while ((k = it.advanceKey()) != null) {
3590	>	if ((u = searchFunction.apply(k)) != null)
3591	>	return u;
3592		}
3593	<	public boolean contains(Object o) {
3594	<	return ConcurrentHashMap.this.containsValue(o);
3593	>	return null;
3594	>	}
3595	>
3596	>	/**
3597	>	* Returns the result of accumulating all keys using the given
3598	>	* reducer to combine values, or null if none.
3599	>	*
3600	>	* @param reducer a commutative associative combining function
3601	>	* @return the result of accumulating all keys using the given
3602	>	* reducer to combine values, or null if none
3603	>	*/
3604	>	public K reduceKeysSequentially
3605	>	(BiFunction<? super K, ? super K, ? extends K> reducer) {
3606	>	if (reducer == null) throw new NullPointerException();
3607	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3608	>	K u, r = null;
3609	>	while ((u = it.advanceKey()) != null) {
3610	>	r = (r == null) ? u : reducer.apply(r, u);
3611		}
3612	<	public void clear() {
3613	<	ConcurrentHashMap.this.clear();
3612	>	return r;
3613	>	}
3614	>
3615	>	/**
3616	>	* Returns the result of accumulating the given transformation
3617	>	* of all keys using the given reducer to combine values, or
3618	>	* null if none.
3619	>	*
3620	>	* @param transformer a function returning the transformation
3621	>	* for an element, or null if there is no transformation (in
3622	>	* which case it is not combined)
3623	>	* @param reducer a commutative associative combining function
3624	>	* @return the result of accumulating the given transformation
3625	>	* of all keys
3626	>	*/
3627	>	public <U> U reduceKeysSequentially
3628	>	(Function<? super K, ? extends U> transformer,
3629	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3630	>	if (transformer == null || reducer == null)
3631	>	throw new NullPointerException();
3632	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3633	>	K k; U r = null, u;
3634	>	while ((k = it.advanceKey()) != null) {
3635	>	if ((u = transformer.apply(k)) != null)
3636	>	r = (r == null) ? u : reducer.apply(r, u);
3637		}
3638	+	return r;
3639	+	}
3640	+
3641	+	/**
3642	+	* Returns the result of accumulating the given transformation
3643	+	* of all keys using the given reducer to combine values, and
3644	+	* the given basis as an identity value.
3645	+	*
3646	+	* @param transformer a function returning the transformation
3647	+	* for an element
3648	+	* @param basis the identity (initial default value) for the reduction
3649	+	* @param reducer a commutative associative combining function
3650	+	* @return the result of accumulating the given transformation
3651	+	* of all keys
3652	+	*/
3653	+	public double reduceKeysToDoubleSequentially
3654	+	(ToDoubleFunction<? super K> transformer,
3655	+	double basis,
3656	+	DoubleBinaryOperator reducer) {
3657	+	if (transformer == null || reducer == null)
3658	+	throw new NullPointerException();
3659	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3660	+	double r = basis;
3661	+	K k;
3662	+	while ((k = it.advanceKey()) != null)
3663	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(k));
3664	+	return r;
3665	+	}
3666	+
3667	+	/**
3668	+	* Returns the result of accumulating the given transformation
3669	+	* of all keys using the given reducer to combine values, and
3670	+	* the given basis as an identity value.
3671	+	*
3672	+	* @param transformer a function returning the transformation
3673	+	* for an element
3674	+	* @param basis the identity (initial default value) for the reduction
3675	+	* @param reducer a commutative associative combining function
3676	+	* @return the result of accumulating the given transformation
3677	+	* of all keys
3678	+	*/
3679	+	public long reduceKeysToLongSequentially
3680	+	(ToLongFunction<? super K> transformer,
3681	+	long basis,
3682	+	LongBinaryOperator reducer) {
3683	+	if (transformer == null || reducer == null)
3684	+	throw new NullPointerException();
3685	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3686	+	long r = basis;
3687	+	K k;
3688	+	while ((k = it.advanceKey()) != null)
3689	+	r = reducer.applyAsLong(r, transformer.applyAsLong(k));
3690	+	return r;
3691	+	}
3692	+
3693	+	/**
3694	+	* Returns the result of accumulating the given transformation
3695	+	* of all keys using the given reducer to combine values, and
3696	+	* the given basis as an identity value.
3697	+	*
3698	+	* @param transformer a function returning the transformation
3699	+	* for an element
3700	+	* @param basis the identity (initial default value) for the reduction
3701	+	* @param reducer a commutative associative combining function
3702	+	* @return the result of accumulating the given transformation
3703	+	* of all keys
3704	+	*/
3705	+	public int reduceKeysToIntSequentially
3706	+	(ToIntFunction<? super K> transformer,
3707	+	int basis,
3708	+	IntBinaryOperator reducer) {
3709	+	if (transformer == null || reducer == null)
3710	+	throw new NullPointerException();
3711	+	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3712	+	int r = basis;
3713	+	K k;
3714	+	while ((k = it.advanceKey()) != null)
3715	+	r = reducer.applyAsInt(r, transformer.applyAsInt(k));
3716	+	return r;
3717		}
3718
3719	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3720	<	public Iterator<Map.Entry<K,V>> iterator() {
3721	<	return new EntryIterator();
3719	>	/**
3720	>	* Performs the given action for each value.
3721	>	*
3722	>	* @param action the action
3723	>	*/
3724	>	public void forEachValueSequentially(Consumer<? super V> action) {
3725	>	new Traverser<K,V,Object>(this).forEachValue(action);
3726	>	}
3727	>
3728	>	/**
3729	>	* Performs the given action for each non-null transformation
3730	>	* of each value.
3731	>	*
3732	>	* @param transformer a function returning the transformation
3733	>	* for an element, or null if there is no transformation (in
3734	>	* which case the action is not applied)
3735	>	* @param action the action
3736	>	*/
3737	>	public <U> void forEachValueSequentially
3738	>	(Function<? super V, ? extends U> transformer,
3739	>	Consumer<? super U> action) {
3740	>	if (transformer == null || action == null)
3741	>	throw new NullPointerException();
3742	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3743	>	V v; U u;
3744	>	while ((v = it.advanceValue()) != null) {
3745	>	if ((u = transformer.apply(v)) != null)
3746	>	action.accept(u);
3747		}
3748	<	public boolean contains(Object o) {
3749	<	if (!(o instanceof Map.Entry))
3750	<	return false;
3751	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3752	<	V v = ConcurrentHashMap.this.get(e.getKey());
3753	<	return v != null && v.equals(e.getValue());
3748	>	}
3749	>
3750	>	/**
3751	>	* Returns a non-null result from applying the given search
3752	>	* function on each value, or null if none.
3753	>	*
3754	>	* @param searchFunction a function returning a non-null
3755	>	* result on success, else null
3756	>	* @return a non-null result from applying the given search
3757	>	* function on each value, or null if none
3758	>	*/
3759	>	public <U> U searchValuesSequentially
3760	>	(Function<? super V, ? extends U> searchFunction) {
3761	>	if (searchFunction == null) throw new NullPointerException();
3762	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3763	>	V v; U u;
3764	>	while ((v = it.advanceValue()) != null) {
3765	>	if ((u = searchFunction.apply(v)) != null)
3766	>	return u;
3767		}
3768	<	public boolean remove(Object o) {
3769	<	if (!(o instanceof Map.Entry))
3770	<	return false;
3771	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3772	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
3768	>	return null;
3769	>	}
3770	>
3771	>	/**
3772	>	* Returns the result of accumulating all values using the
3773	>	* given reducer to combine values, or null if none.
3774	>	*
3775	>	* @param reducer a commutative associative combining function
3776	>	* @return the result of accumulating all values
3777	>	*/
3778	>	public V reduceValuesSequentially
3779	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
3780	>	if (reducer == null) throw new NullPointerException();
3781	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3782	>	V r = null; V v;
3783	>	while ((v = it.advanceValue()) != null)
3784	>	r = (r == null) ? v : reducer.apply(r, v);
3785	>	return r;
3786	>	}
3787	>
3788	>	/**
3789	>	* Returns the result of accumulating the given transformation
3790	>	* of all values using the given reducer to combine values, or
3791	>	* null if none.
3792	>	*
3793	>	* @param transformer a function returning the transformation
3794	>	* for an element, or null if there is no transformation (in
3795	>	* which case it is not combined)
3796	>	* @param reducer a commutative associative combining function
3797	>	* @return the result of accumulating the given transformation
3798	>	* of all values
3799	>	*/
3800	>	public <U> U reduceValuesSequentially
3801	>	(Function<? super V, ? extends U> transformer,
3802	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3803	>	if (transformer == null || reducer == null)
3804	>	throw new NullPointerException();
3805	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3806	>	U r = null, u; V v;
3807	>	while ((v = it.advanceValue()) != null) {
3808	>	if ((u = transformer.apply(v)) != null)
3809	>	r = (r == null) ? u : reducer.apply(r, u);
3810		}
3811	<	public int size() {
3812	<	return ConcurrentHashMap.this.size();
3811	>	return r;
3812	>	}
3813	>
3814	>	/**
3815	>	* Returns the result of accumulating the given transformation
3816	>	* of all values using the given reducer to combine values,
3817	>	* and the given basis as an identity value.
3818	>	*
3819	>	* @param transformer a function returning the transformation
3820	>	* for an element
3821	>	* @param basis the identity (initial default value) for the reduction
3822	>	* @param reducer a commutative associative combining function
3823	>	* @return the result of accumulating the given transformation
3824	>	* of all values
3825	>	*/
3826	>	public double reduceValuesToDoubleSequentially
3827	>	(ToDoubleFunction<? super V> transformer,
3828	>	double basis,
3829	>	DoubleBinaryOperator reducer) {
3830	>	if (transformer == null || reducer == null)
3831	>	throw new NullPointerException();
3832	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3833	>	double r = basis; V v;
3834	>	while ((v = it.advanceValue()) != null)
3835	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
3836	>	return r;
3837	>	}
3838	>
3839	>	/**
3840	>	* Returns the result of accumulating the given transformation
3841	>	* of all values using the given reducer to combine values,
3842	>	* and the given basis as an identity value.
3843	>	*
3844	>	* @param transformer a function returning the transformation
3845	>	* for an element
3846	>	* @param basis the identity (initial default value) for the reduction
3847	>	* @param reducer a commutative associative combining function
3848	>	* @return the result of accumulating the given transformation
3849	>	* of all values
3850	>	*/
3851	>	public long reduceValuesToLongSequentially
3852	>	(ToLongFunction<? super V> transformer,
3853	>	long basis,
3854	>	LongBinaryOperator reducer) {
3855	>	if (transformer == null || reducer == null)
3856	>	throw new NullPointerException();
3857	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3858	>	long r = basis; V v;
3859	>	while ((v = it.advanceValue()) != null)
3860	>	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
3861	>	return r;
3862	>	}
3863	>
3864	>	/**
3865	>	* Returns the result of accumulating the given transformation
3866	>	* of all values using the given reducer to combine values,
3867	>	* and the given basis as an identity value.
3868	>	*
3869	>	* @param transformer a function returning the transformation
3870	>	* for an element
3871	>	* @param basis the identity (initial default value) for the reduction
3872	>	* @param reducer a commutative associative combining function
3873	>	* @return the result of accumulating the given transformation
3874	>	* of all values
3875	>	*/
3876	>	public int reduceValuesToIntSequentially
3877	>	(ToIntFunction<? super V> transformer,
3878	>	int basis,
3879	>	IntBinaryOperator reducer) {
3880	>	if (transformer == null || reducer == null)
3881	>	throw new NullPointerException();
3882	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3883	>	int r = basis; V v;
3884	>	while ((v = it.advanceValue()) != null)
3885	>	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
3886	>	return r;
3887	>	}
3888	>
3889	>	/**
3890	>	* Performs the given action for each entry.
3891	>	*
3892	>	* @param action the action
3893	>	*/
3894	>	public void forEachEntrySequentially
3895	>	(Consumer<? super Map.Entry<K,V>> action) {
3896	>	if (action == null) throw new NullPointerException();
3897	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3898	>	V v;
3899	>	while ((v = it.advanceValue()) != null)
3900	>	action.accept(entryFor(it.nextKey, v));
3901	>	}
3902	>
3903	>	/**
3904	>	* Performs the given action for each non-null transformation
3905	>	* of each entry.
3906	>	*
3907	>	* @param transformer a function returning the transformation
3908	>	* for an element, or null if there is no transformation (in
3909	>	* which case the action is not applied)
3910	>	* @param action the action
3911	>	*/
3912	>	public <U> void forEachEntrySequentially
3913	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3914	>	Consumer<? super U> action) {
3915	>	if (transformer == null || action == null)
3916	>	throw new NullPointerException();
3917	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3918	>	V v; U u;
3919	>	while ((v = it.advanceValue()) != null) {
3920	>	if ((u = transformer.apply(entryFor(it.nextKey, v))) != null)
3921	>	action.accept(u);
3922		}
3923	<	public boolean isEmpty() {
3924	<	return ConcurrentHashMap.this.isEmpty();
3923	>	}
3924	>
3925	>	/**
3926	>	* Returns a non-null result from applying the given search
3927	>	* function on each entry, or null if none.
3928	>	*
3929	>	* @param searchFunction a function returning a non-null
3930	>	* result on success, else null
3931	>	* @return a non-null result from applying the given search
3932	>	* function on each entry, or null if none
3933	>	*/
3934	>	public <U> U searchEntriesSequentially
3935	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
3936	>	if (searchFunction == null) throw new NullPointerException();
3937	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3938	>	V v; U u;
3939	>	while ((v = it.advanceValue()) != null) {
3940	>	if ((u = searchFunction.apply(entryFor(it.nextKey, v))) != null)
3941	>	return u;
3942		}
3943	<	public void clear() {
3944	<	ConcurrentHashMap.this.clear();
3943	>	return null;
3944	>	}
3945	>
3946	>	/**
3947	>	* Returns the result of accumulating all entries using the
3948	>	* given reducer to combine values, or null if none.
3949	>	*
3950	>	* @param reducer a commutative associative combining function
3951	>	* @return the result of accumulating all entries
3952	>	*/
3953	>	public Map.Entry<K,V> reduceEntriesSequentially
3954	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3955	>	if (reducer == null) throw new NullPointerException();
3956	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3957	>	Map.Entry<K,V> r = null; V v;
3958	>	while ((v = it.advanceValue()) != null) {
3959	>	Map.Entry<K,V> u = entryFor(it.nextKey, v);
3960	>	r = (r == null) ? u : reducer.apply(r, u);
3961		}
3962	+	return r;
3963		}
3964
3965	<	/* ---------------- Serialization Support -------------- */
3965	>	/**
3966	>	* Returns the result of accumulating the given transformation
3967	>	* of all entries using the given reducer to combine values,
3968	>	* or null if none.
3969	>	*
3970	>	* @param transformer a function returning the transformation
3971	>	* for an element, or null if there is no transformation (in
3972	>	* which case it is not combined)
3973	>	* @param reducer a commutative associative combining function
3974	>	* @return the result of accumulating the given transformation
3975	>	* of all entries
3976	>	*/
3977	>	public <U> U reduceEntriesSequentially
3978	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3979	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3980	>	if (transformer == null || reducer == null)
3981	>	throw new NullPointerException();
3982	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3983	>	U r = null, u; V v;
3984	>	while ((v = it.advanceValue()) != null) {
3985	>	if ((u = transformer.apply(entryFor(it.nextKey, v))) != null)
3986	>	r = (r == null) ? u : reducer.apply(r, u);
3987	>	}
3988	>	return r;
3989	>	}
3990
3991		/**
3992	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
3993	<	* stream (i.e., serializes it).
3994	<	* @param s the stream
3995	<	* @serialData
3996	<	* the key (Object) and value (Object)
3997	<	* for each key-value mapping, followed by a null pair.
3998	<	* The key-value mappings are emitted in no particular order.
3992	>	* Returns the result of accumulating the given transformation
3993	>	* of all entries using the given reducer to combine values,
3994	>	* and the given basis as an identity value.
3995	>	*
3996	>	* @param transformer a function returning the transformation
3997	>	* for an element
3998	>	* @param basis the identity (initial default value) for the reduction
3999	>	* @param reducer a commutative associative combining function
4000	>	* @return the result of accumulating the given transformation
4001	>	* of all entries
4002	>	*/
4003	>	public double reduceEntriesToDoubleSequentially
4004	>	(ToDoubleFunction<Map.Entry<K,V>> transformer,
4005	>	double basis,
4006	>	DoubleBinaryOperator reducer) {
4007	>	if (transformer == null || reducer == null)
4008	>	throw new NullPointerException();
4009	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
4010	>	double r = basis; V v;
4011	>	while ((v = it.advanceValue()) != null)
4012	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor(it.nextKey, v)));
4013	>	return r;
4014	>	}
4015	>
4016	>	/**
4017	>	* Returns the result of accumulating the given transformation
4018	>	* of all entries using the given reducer to combine values,
4019	>	* and the given basis as an identity value.
4020	>	*
4021	>	* @param transformer a function returning the transformation
4022	>	* for an element
4023	>	* @param basis the identity (initial default value) for the reduction
4024	>	* @param reducer a commutative associative combining function
4025	>	* @return the result of accumulating the given transformation
4026	>	* of all entries
4027	>	*/
4028	>	public long reduceEntriesToLongSequentially
4029	>	(ToLongFunction<Map.Entry<K,V>> transformer,
4030	>	long basis,
4031	>	LongBinaryOperator reducer) {
4032	>	if (transformer == null || reducer == null)
4033	>	throw new NullPointerException();
4034	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
4035	>	long r = basis; V v;
4036	>	while ((v = it.advanceValue()) != null)
4037	>	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor(it.nextKey, v)));
4038	>	return r;
4039	>	}
4040	>
4041	>	/**
4042	>	* Returns the result of accumulating the given transformation
4043	>	* of all entries using the given reducer to combine values,
4044	>	* and the given basis as an identity value.
4045	>	*
4046	>	* @param transformer a function returning the transformation
4047	>	* for an element
4048	>	* @param basis the identity (initial default value) for the reduction
4049	>	* @param reducer a commutative associative combining function
4050	>	* @return the result of accumulating the given transformation
4051	>	* of all entries
4052	>	*/
4053	>	public int reduceEntriesToIntSequentially
4054	>	(ToIntFunction<Map.Entry<K,V>> transformer,
4055	>	int basis,
4056	>	IntBinaryOperator reducer) {
4057	>	if (transformer == null || reducer == null)
4058	>	throw new NullPointerException();
4059	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
4060	>	int r = basis; V v;
4061	>	while ((v = it.advanceValue()) != null)
4062	>	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor(it.nextKey, v)));
4063	>	return r;
4064	>	}
4065	>
4066	>	// Parallel bulk operations
4067	>
4068	>	/**
4069	>	* Performs the given action for each (key, value).
4070	>	*
4071	>	* @param action the action
4072		*/
4073	<	private void writeObject(java.io.ObjectOutputStream s)
4074	<	throws java.io.IOException {
4075	<	// force all segments for serialization compatibility
4076	<	for (int k = 0; k < segments.length; ++k)
1404	<	ensureSegment(k);
1405	<	s.defaultWriteObject();
4073	>	public void forEachInParallel(BiConsumer<? super K,? super V> action) {
4074	>	ForkJoinTasks.forEach
4075	>	(this, action).invoke();
4076	>	}
4077
4078	<	final Segment<K,V>[] segments = this.segments;
4079	<	for (int k = 0; k < segments.length; ++k) {
4080	<	Segment<K,V> seg = segmentAt(segments, k);
4081	<	seg.lock();
4082	<	try {
4083	<	HashEntry<K,V>[] tab = seg.table;
4084	<	for (int i = 0; i < tab.length; ++i) {
4085	<	HashEntry<K,V> e;
4086	<	for (e = entryAt(tab, i); e != null; e = e.next) {
4087	<	s.writeObject(e.key);
4088	<	s.writeObject(e.value);
4078	>	/**
4079	>	* Performs the given action for each non-null transformation
4080	>	* of each (key, value).
4081	>	*
4082	>	* @param transformer a function returning the transformation
4083	>	* for an element, or null if there is no transformation (in
4084	>	* which case the action is not applied)
4085	>	* @param action the action
4086	>	*/
4087	>	public <U> void forEachInParallel
4088	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
4089	>	Consumer<? super U> action) {
4090	>	ForkJoinTasks.forEach
4091	>	(this, transformer, action).invoke();
4092	>	}
4093	>
4094	>	/**
4095	>	* Returns a non-null result from applying the given search
4096	>	* function on each (key, value), or null if none.  Upon
4097	>	* success, further element processing is suppressed and the
4098	>	* results of any other parallel invocations of the search
4099	>	* function are ignored.
4100	>	*
4101	>	* @param searchFunction a function returning a non-null
4102	>	* result on success, else null
4103	>	* @return a non-null result from applying the given search
4104	>	* function on each (key, value), or null if none
4105	>	*/
4106	>	public <U> U searchInParallel
4107	>	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
4108	>	return ForkJoinTasks.search
4109	>	(this, searchFunction).invoke();
4110	>	}
4111	>
4112	>	/**
4113	>	* Returns the result of accumulating the given transformation
4114	>	* of all (key, value) pairs using the given reducer to
4115	>	* combine values, or null if none.
4116	>	*
4117	>	* @param transformer a function returning the transformation
4118	>	* for an element, or null if there is no transformation (in
4119	>	* which case it is not combined)
4120	>	* @param reducer a commutative associative combining function
4121	>	* @return the result of accumulating the given transformation
4122	>	* of all (key, value) pairs
4123	>	*/
4124	>	public <U> U reduceInParallel
4125	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
4126	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4127	>	return ForkJoinTasks.reduce
4128	>	(this, transformer, reducer).invoke();
4129	>	}
4130	>
4131	>	/**
4132	>	* Returns the result of accumulating the given transformation
4133	>	* of all (key, value) pairs using the given reducer to
4134	>	* combine values, and the given basis as an identity value.
4135	>	*
4136	>	* @param transformer a function returning the transformation
4137	>	* for an element
4138	>	* @param basis the identity (initial default value) for the reduction
4139	>	* @param reducer a commutative associative combining function
4140	>	* @return the result of accumulating the given transformation
4141	>	* of all (key, value) pairs
4142	>	*/
4143	>	public double reduceToDoubleInParallel
4144	>	(ToDoubleBiFunction<? super K, ? super V> transformer,
4145	>	double basis,
4146	>	DoubleBinaryOperator reducer) {
4147	>	return ForkJoinTasks.reduceToDouble
4148	>	(this, transformer, basis, reducer).invoke();
4149	>	}
4150	>
4151	>	/**
4152	>	* Returns the result of accumulating the given transformation
4153	>	* of all (key, value) pairs using the given reducer to
4154	>	* combine values, and the given basis as an identity value.
4155	>	*
4156	>	* @param transformer a function returning the transformation
4157	>	* for an element
4158	>	* @param basis the identity (initial default value) for the reduction
4159	>	* @param reducer a commutative associative combining function
4160	>	* @return the result of accumulating the given transformation
4161	>	* of all (key, value) pairs
4162	>	*/
4163	>	public long reduceToLongInParallel
4164	>	(ToLongBiFunction<? super K, ? super V> transformer,
4165	>	long basis,
4166	>	LongBinaryOperator reducer) {
4167	>	return ForkJoinTasks.reduceToLong
4168	>	(this, transformer, basis, reducer).invoke();
4169	>	}
4170	>
4171	>	/**
4172	>	* Returns the result of accumulating the given transformation
4173	>	* of all (key, value) pairs using the given reducer to
4174	>	* combine values, and the given basis as an identity value.
4175	>	*
4176	>	* @param transformer a function returning the transformation
4177	>	* for an element
4178	>	* @param basis the identity (initial default value) for the reduction
4179	>	* @param reducer a commutative associative combining function
4180	>	* @return the result of accumulating the given transformation
4181	>	* of all (key, value) pairs
4182	>	*/
4183	>	public int reduceToIntInParallel
4184	>	(ToIntBiFunction<? super K, ? super V> transformer,
4185	>	int basis,
4186	>	IntBinaryOperator reducer) {
4187	>	return ForkJoinTasks.reduceToInt
4188	>	(this, transformer, basis, reducer).invoke();
4189	>	}
4190	>
4191	>	/**
4192	>	* Performs the given action for each key.
4193	>	*
4194	>	* @param action the action
4195	>	*/
4196	>	public void forEachKeyInParallel(Consumer<? super K> action) {
4197	>	ForkJoinTasks.forEachKey
4198	>	(this, action).invoke();
4199	>	}
4200	>
4201	>	/**
4202	>	* Performs the given action for each non-null transformation
4203	>	* of each key.
4204	>	*
4205	>	* @param transformer a function returning the transformation
4206	>	* for an element, or null if there is no transformation (in
4207	>	* which case the action is not applied)
4208	>	* @param action the action
4209	>	*/
4210	>	public <U> void forEachKeyInParallel
4211	>	(Function<? super K, ? extends U> transformer,
4212	>	Consumer<? super U> action) {
4213	>	ForkJoinTasks.forEachKey
4214	>	(this, transformer, action).invoke();
4215	>	}
4216	>
4217	>	/**
4218	>	* Returns a non-null result from applying the given search
4219	>	* function on each key, or null if none. Upon success,
4220	>	* further element processing is suppressed and the results of
4221	>	* any other parallel invocations of the search function are
4222	>	* ignored.
4223	>	*
4224	>	* @param searchFunction a function returning a non-null
4225	>	* result on success, else null
4226	>	* @return a non-null result from applying the given search
4227	>	* function on each key, or null if none
4228	>	*/
4229	>	public <U> U searchKeysInParallel
4230	>	(Function<? super K, ? extends U> searchFunction) {
4231	>	return ForkJoinTasks.searchKeys
4232	>	(this, searchFunction).invoke();
4233	>	}
4234	>
4235	>	/**
4236	>	* Returns the result of accumulating all keys using the given
4237	>	* reducer to combine values, or null if none.
4238	>	*
4239	>	* @param reducer a commutative associative combining function
4240	>	* @return the result of accumulating all keys using the given
4241	>	* reducer to combine values, or null if none
4242	>	*/
4243	>	public K reduceKeysInParallel
4244	>	(BiFunction<? super K, ? super K, ? extends K> reducer) {
4245	>	return ForkJoinTasks.reduceKeys
4246	>	(this, reducer).invoke();
4247	>	}
4248	>
4249	>	/**
4250	>	* Returns the result of accumulating the given transformation
4251	>	* of all keys using the given reducer to combine values, or
4252	>	* null if none.
4253	>	*
4254	>	* @param transformer a function returning the transformation
4255	>	* for an element, or null if there is no transformation (in
4256	>	* which case it is not combined)
4257	>	* @param reducer a commutative associative combining function
4258	>	* @return the result of accumulating the given transformation
4259	>	* of all keys
4260	>	*/
4261	>	public <U> U reduceKeysInParallel
4262	>	(Function<? super K, ? extends U> transformer,
4263	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4264	>	return ForkJoinTasks.reduceKeys
4265	>	(this, transformer, reducer).invoke();
4266	>	}
4267	>
4268	>	/**
4269	>	* Returns the result of accumulating the given transformation
4270	>	* of all keys using the given reducer to combine values, and
4271	>	* the given basis as an identity value.
4272	>	*
4273	>	* @param transformer a function returning the transformation
4274	>	* for an element
4275	>	* @param basis the identity (initial default value) for the reduction
4276	>	* @param reducer a commutative associative combining function
4277	>	* @return the result of accumulating the given transformation
4278	>	* of all keys
4279	>	*/
4280	>	public double reduceKeysToDoubleInParallel
4281	>	(ToDoubleFunction<? super K> transformer,
4282	>	double basis,
4283	>	DoubleBinaryOperator reducer) {
4284	>	return ForkJoinTasks.reduceKeysToDouble
4285	>	(this, transformer, basis, reducer).invoke();
4286	>	}
4287	>
4288	>	/**
4289	>	* Returns the result of accumulating the given transformation
4290	>	* of all keys using the given reducer to combine values, and
4291	>	* the given basis as an identity value.
4292	>	*
4293	>	* @param transformer a function returning the transformation
4294	>	* for an element
4295	>	* @param basis the identity (initial default value) for the reduction
4296	>	* @param reducer a commutative associative combining function
4297	>	* @return the result of accumulating the given transformation
4298	>	* of all keys
4299	>	*/
4300	>	public long reduceKeysToLongInParallel
4301	>	(ToLongFunction<? super K> transformer,
4302	>	long basis,
4303	>	LongBinaryOperator reducer) {
4304	>	return ForkJoinTasks.reduceKeysToLong
4305	>	(this, transformer, basis, reducer).invoke();
4306	>	}
4307	>
4308	>	/**
4309	>	* Returns the result of accumulating the given transformation
4310	>	* of all keys using the given reducer to combine values, and
4311	>	* the given basis as an identity value.
4312	>	*
4313	>	* @param transformer a function returning the transformation
4314	>	* for an element
4315	>	* @param basis the identity (initial default value) for the reduction
4316	>	* @param reducer a commutative associative combining function
4317	>	* @return the result of accumulating the given transformation
4318	>	* of all keys
4319	>	*/
4320	>	public int reduceKeysToIntInParallel
4321	>	(ToIntFunction<? super K> transformer,
4322	>	int basis,
4323	>	IntBinaryOperator reducer) {
4324	>	return ForkJoinTasks.reduceKeysToInt
4325	>	(this, transformer, basis, reducer).invoke();
4326	>	}
4327	>
4328	>	/**
4329	>	* Performs the given action for each value.
4330	>	*
4331	>	* @param action the action
4332	>	*/
4333	>	public void forEachValueInParallel(Consumer<? super V> action) {
4334	>	ForkJoinTasks.forEachValue
4335	>	(this, action).invoke();
4336	>	}
4337	>
4338	>	/**
4339	>	* Performs the given action for each non-null transformation
4340	>	* of each value.
4341	>	*
4342	>	* @param transformer a function returning the transformation
4343	>	* for an element, or null if there is no transformation (in
4344	>	* which case the action is not applied)
4345	>	* @param action the action
4346	>	*/
4347	>	public <U> void forEachValueInParallel
4348	>	(Function<? super V, ? extends U> transformer,
4349	>	Consumer<? super U> action) {
4350	>	ForkJoinTasks.forEachValue
4351	>	(this, transformer, action).invoke();
4352	>	}
4353	>
4354	>	/**
4355	>	* Returns a non-null result from applying the given search
4356	>	* function on each value, or null if none.  Upon success,
4357	>	* further element processing is suppressed and the results of
4358	>	* any other parallel invocations of the search function are
4359	>	* ignored.
4360	>	*
4361	>	* @param searchFunction a function returning a non-null
4362	>	* result on success, else null
4363	>	* @return a non-null result from applying the given search
4364	>	* function on each value, or null if none
4365	>	*/
4366	>	public <U> U searchValuesInParallel
4367	>	(Function<? super V, ? extends U> searchFunction) {
4368	>	return ForkJoinTasks.searchValues
4369	>	(this, searchFunction).invoke();
4370	>	}
4371	>
4372	>	/**
4373	>	* Returns the result of accumulating all values using the
4374	>	* given reducer to combine values, or null if none.
4375	>	*
4376	>	* @param reducer a commutative associative combining function
4377	>	* @return the result of accumulating all values
4378	>	*/
4379	>	public V reduceValuesInParallel
4380	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
4381	>	return ForkJoinTasks.reduceValues
4382	>	(this, reducer).invoke();
4383	>	}
4384	>
4385	>	/**
4386	>	* Returns the result of accumulating the given transformation
4387	>	* of all values using the given reducer to combine values, or
4388	>	* null if none.
4389	>	*
4390	>	* @param transformer a function returning the transformation
4391	>	* for an element, or null if there is no transformation (in
4392	>	* which case it is not combined)
4393	>	* @param reducer a commutative associative combining function
4394	>	* @return the result of accumulating the given transformation
4395	>	* of all values
4396	>	*/
4397	>	public <U> U reduceValuesInParallel
4398	>	(Function<? super V, ? extends U> transformer,
4399	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4400	>	return ForkJoinTasks.reduceValues
4401	>	(this, transformer, reducer).invoke();
4402	>	}
4403	>
4404	>	/**
4405	>	* Returns the result of accumulating the given transformation
4406	>	* of all values using the given reducer to combine values,
4407	>	* and the given basis as an identity value.
4408	>	*
4409	>	* @param transformer a function returning the transformation
4410	>	* for an element
4411	>	* @param basis the identity (initial default value) for the reduction
4412	>	* @param reducer a commutative associative combining function
4413	>	* @return the result of accumulating the given transformation
4414	>	* of all values
4415	>	*/
4416	>	public double reduceValuesToDoubleInParallel
4417	>	(ToDoubleFunction<? super V> transformer,
4418	>	double basis,
4419	>	DoubleBinaryOperator reducer) {
4420	>	return ForkJoinTasks.reduceValuesToDouble
4421	>	(this, transformer, basis, reducer).invoke();
4422	>	}
4423	>
4424	>	/**
4425	>	* Returns the result of accumulating the given transformation
4426	>	* of all values using the given reducer to combine values,
4427	>	* and the given basis as an identity value.
4428	>	*
4429	>	* @param transformer a function returning the transformation
4430	>	* for an element
4431	>	* @param basis the identity (initial default value) for the reduction
4432	>	* @param reducer a commutative associative combining function
4433	>	* @return the result of accumulating the given transformation
4434	>	* of all values
4435	>	*/
4436	>	public long reduceValuesToLongInParallel
4437	>	(ToLongFunction<? super V> transformer,
4438	>	long basis,
4439	>	LongBinaryOperator reducer) {
4440	>	return ForkJoinTasks.reduceValuesToLong
4441	>	(this, transformer, basis, reducer).invoke();
4442	>	}
4443	>
4444	>	/**
4445	>	* Returns the result of accumulating the given transformation
4446	>	* of all values using the given reducer to combine values,
4447	>	* and the given basis as an identity value.
4448	>	*
4449	>	* @param transformer a function returning the transformation
4450	>	* for an element
4451	>	* @param basis the identity (initial default value) for the reduction
4452	>	* @param reducer a commutative associative combining function
4453	>	* @return the result of accumulating the given transformation
4454	>	* of all values
4455	>	*/
4456	>	public int reduceValuesToIntInParallel
4457	>	(ToIntFunction<? super V> transformer,
4458	>	int basis,
4459	>	IntBinaryOperator reducer) {
4460	>	return ForkJoinTasks.reduceValuesToInt
4461	>	(this, transformer, basis, reducer).invoke();
4462	>	}
4463	>
4464	>	/**
4465	>	* Performs the given action for each entry.
4466	>	*
4467	>	* @param action the action
4468	>	*/
4469	>	public void forEachEntryInParallel(Consumer<? super Map.Entry<K,V>> action) {
4470	>	ForkJoinTasks.forEachEntry
4471	>	(this, action).invoke();
4472	>	}
4473	>
4474	>	/**
4475	>	* Performs the given action for each non-null transformation
4476	>	* of each entry.
4477	>	*
4478	>	* @param transformer a function returning the transformation
4479	>	* for an element, or null if there is no transformation (in
4480	>	* which case the action is not applied)
4481	>	* @param action the action
4482	>	*/
4483	>	public <U> void forEachEntryInParallel
4484	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4485	>	Consumer<? super U> action) {
4486	>	ForkJoinTasks.forEachEntry
4487	>	(this, transformer, action).invoke();
4488	>	}
4489	>
4490	>	/**
4491	>	* Returns a non-null result from applying the given search
4492	>	* function on each entry, or null if none.  Upon success,
4493	>	* further element processing is suppressed and the results of
4494	>	* any other parallel invocations of the search function are
4495	>	* ignored.
4496	>	*
4497	>	* @param searchFunction a function returning a non-null
4498	>	* result on success, else null
4499	>	* @return a non-null result from applying the given search
4500	>	* function on each entry, or null if none
4501	>	*/
4502	>	public <U> U searchEntriesInParallel
4503	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4504	>	return ForkJoinTasks.searchEntries
4505	>	(this, searchFunction).invoke();
4506	>	}
4507	>
4508	>	/**
4509	>	* Returns the result of accumulating all entries using the
4510	>	* given reducer to combine values, or null if none.
4511	>	*
4512	>	* @param reducer a commutative associative combining function
4513	>	* @return the result of accumulating all entries
4514	>	*/
4515	>	public Map.Entry<K,V> reduceEntriesInParallel
4516	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4517	>	return ForkJoinTasks.reduceEntries
4518	>	(this, reducer).invoke();
4519	>	}
4520	>
4521	>	/**
4522	>	* Returns the result of accumulating the given transformation
4523	>	* of all entries using the given reducer to combine values,
4524	>	* or null if none.
4525	>	*
4526	>	* @param transformer a function returning the transformation
4527	>	* for an element, or null if there is no transformation (in
4528	>	* which case it is not combined)
4529	>	* @param reducer a commutative associative combining function
4530	>	* @return the result of accumulating the given transformation
4531	>	* of all entries
4532	>	*/
4533	>	public <U> U reduceEntriesInParallel
4534	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4535	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4536	>	return ForkJoinTasks.reduceEntries
4537	>	(this, transformer, reducer).invoke();
4538	>	}
4539	>
4540	>	/**
4541	>	* Returns the result of accumulating the given transformation
4542	>	* of all entries using the given reducer to combine values,
4543	>	* and the given basis as an identity value.
4544	>	*
4545	>	* @param transformer a function returning the transformation
4546	>	* for an element
4547	>	* @param basis the identity (initial default value) for the reduction
4548	>	* @param reducer a commutative associative combining function
4549	>	* @return the result of accumulating the given transformation
4550	>	* of all entries
4551	>	*/
4552	>	public double reduceEntriesToDoubleInParallel
4553	>	(ToDoubleFunction<Map.Entry<K,V>> transformer,
4554	>	double basis,
4555	>	DoubleBinaryOperator reducer) {
4556	>	return ForkJoinTasks.reduceEntriesToDouble
4557	>	(this, transformer, basis, reducer).invoke();
4558	>	}
4559	>
4560	>	/**
4561	>	* Returns the result of accumulating the given transformation
4562	>	* of all entries using the given reducer to combine values,
4563	>	* and the given basis as an identity value.
4564	>	*
4565	>	* @param transformer a function returning the transformation
4566	>	* for an element
4567	>	* @param basis the identity (initial default value) for the reduction
4568	>	* @param reducer a commutative associative combining function
4569	>	* @return the result of accumulating the given transformation
4570	>	* of all entries
4571	>	*/
4572	>	public long reduceEntriesToLongInParallel
4573	>	(ToLongFunction<Map.Entry<K,V>> transformer,
4574	>	long basis,
4575	>	LongBinaryOperator reducer) {
4576	>	return ForkJoinTasks.reduceEntriesToLong
4577	>	(this, transformer, basis, reducer).invoke();
4578	>	}
4579	>
4580	>	/**
4581	>	* Returns the result of accumulating the given transformation
4582	>	* of all entries using the given reducer to combine values,
4583	>	* and the given basis as an identity value.
4584	>	*
4585	>	* @param transformer a function returning the transformation
4586	>	* for an element
4587	>	* @param basis the identity (initial default value) for the reduction
4588	>	* @param reducer a commutative associative combining function
4589	>	* @return the result of accumulating the given transformation
4590	>	* of all entries
4591	>	*/
4592	>	public int reduceEntriesToIntInParallel
4593	>	(ToIntFunction<Map.Entry<K,V>> transformer,
4594	>	int basis,
4595	>	IntBinaryOperator reducer) {
4596	>	return ForkJoinTasks.reduceEntriesToInt
4597	>	(this, transformer, basis, reducer).invoke();
4598	>	}
4599	>
4600	>
4601	>	/* ----------------Views -------------- */
4602	>
4603	>	/**
4604	>	* Base class for views.
4605	>	*/
4606	>	abstract static class CHMCollectionView<K,V,E>
4607	>	implements Collection<E>, java.io.Serializable {
4608	>	private static final long serialVersionUID = 7249069246763182397L;
4609	>	final ConcurrentHashMap<K,V> map;
4610	>	CHMCollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4611	>
4612	>	/**
4613	>	* Returns the map backing this view.
4614	>	*
4615	>	* @return the map backing this view
4616	>	*/
4617	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4618	>
4619	>	/**
4620	>	* Removes all of the elements from this view, by removing all
4621	>	* the mappings from the map backing this view.
4622	>	*/
4623	>	public final void clear()      { map.clear(); }
4624	>	public final int size()        { return map.size(); }
4625	>	public final boolean isEmpty() { return map.isEmpty(); }
4626	>
4627	>	// implementations below rely on concrete classes supplying these
4628	>	// abstract methods
4629	>	/**
4630	>	* Returns a "weakly consistent" iterator that will never
4631	>	* throw {@link ConcurrentModificationException}, and
4632	>	* guarantees to traverse elements as they existed upon
4633	>	* construction of the iterator, and may (but is not
4634	>	* guaranteed to) reflect any modifications subsequent to
4635	>	* construction.
4636	>	*/
4637	>	public abstract Iterator<E> iterator();
4638	>	public abstract boolean contains(Object o);
4639	>	public abstract boolean remove(Object o);
4640	>
4641	>	private static final String oomeMsg = "Required array size too large";
4642	>
4643	>	public final Object[] toArray() {
4644	>	long sz = map.mappingCount();
4645	>	if (sz > MAX_ARRAY_SIZE)
4646	>	throw new OutOfMemoryError(oomeMsg);
4647	>	int n = (int)sz;
4648	>	Object[] r = new Object[n];
4649	>	int i = 0;
4650	>	for (E e : this) {
4651	>	if (i == n) {
4652	>	if (n >= MAX_ARRAY_SIZE)
4653	>	throw new OutOfMemoryError(oomeMsg);
4654	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4655	>	n = MAX_ARRAY_SIZE;
4656	>	else
4657	>	n += (n >>> 1) + 1;
4658	>	r = Arrays.copyOf(r, n);
4659	>	}
4660	>	r[i++] = e;
4661	>	}
4662	>	return (i == n) ? r : Arrays.copyOf(r, i);
4663	>	}
4664	>
4665	>	@SuppressWarnings("unchecked")
4666	>	public final <T> T[] toArray(T[] a) {
4667	>	long sz = map.mappingCount();
4668	>	if (sz > MAX_ARRAY_SIZE)
4669	>	throw new OutOfMemoryError(oomeMsg);
4670	>	int m = (int)sz;
4671	>	T[] r = (a.length >= m) ? a :
4672	>	(T[])java.lang.reflect.Array
4673	>	.newInstance(a.getClass().getComponentType(), m);
4674	>	int n = r.length;
4675	>	int i = 0;
4676	>	for (E e : this) {
4677	>	if (i == n) {
4678	>	if (n >= MAX_ARRAY_SIZE)
4679	>	throw new OutOfMemoryError(oomeMsg);
4680	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4681	>	n = MAX_ARRAY_SIZE;
4682	>	else
4683	>	n += (n >>> 1) + 1;
4684	>	r = Arrays.copyOf(r, n);
4685	>	}
4686	>	r[i++] = (T)e;
4687	>	}
4688	>	if (a == r && i < n) {
4689	>	r[i] = null; // null-terminate
4690	>	return r;
4691	>	}
4692	>	return (i == n) ? r : Arrays.copyOf(r, i);
4693	>	}
4694	>
4695	>	/**
4696	>	* Returns a string representation of this collection.
4697	>	* The string representation consists of the string representations
4698	>	* of the collection's elements in the order they are returned by
4699	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4700	>	* Adjacent elements are separated by the characters {@code ", "}
4701	>	* (comma and space).  Elements are converted to strings as by
4702	>	* {@link String#valueOf(Object)}.
4703	>	*
4704	>	* @return a string representation of this collection
4705	>	*/
4706	>	public final String toString() {
4707	>	StringBuilder sb = new StringBuilder();
4708	>	sb.append('[');
4709	>	Iterator<E> it = iterator();
4710	>	if (it.hasNext()) {
4711	>	for (;;) {
4712	>	Object e = it.next();
4713	>	sb.append(e == this ? "(this Collection)" : e);
4714	>	if (!it.hasNext())
4715	>	break;
4716	>	sb.append(',').append(' ');
4717	>	}
4718	>	}
4719	>	return sb.append(']').toString();
4720	>	}
4721	>
4722	>	public final boolean containsAll(Collection<?> c) {
4723	>	if (c != this) {
4724	>	for (Object e : c) {
4725	>	if (e == null || !contains(e))
4726	>	return false;
4727	>	}
4728	>	}
4729	>	return true;
4730	>	}
4731	>
4732	>	public final boolean removeAll(Collection<?> c) {
4733	>	boolean modified = false;
4734	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4735	>	if (c.contains(it.next())) {
4736	>	it.remove();
4737	>	modified = true;
4738	>	}
4739	>	}
4740	>	return modified;
4741	>	}
4742	>
4743	>	public final boolean retainAll(Collection<?> c) {
4744	>	boolean modified = false;
4745	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4746	>	if (!c.contains(it.next())) {
4747	>	it.remove();
4748	>	modified = true;
4749	>	}
4750	>	}
4751	>	return modified;
4752	>	}
4753	>
4754	>	}
4755	>
4756	>	abstract static class CHMSetView<K,V,E>
4757	>	extends CHMCollectionView<K,V,E>
4758	>	implements Set<E>, java.io.Serializable {
4759	>	private static final long serialVersionUID = 7249069246763182397L;
4760	>	CHMSetView(ConcurrentHashMap<K,V> map) { super(map); }
4761	>
4762	>	// Implement Set API
4763	>
4764	>	/**
4765	>	* Implements {@link Set#hashCode()}.
4766	>	* @return the hash code value for this set
4767	>	*/
4768	>	public final int hashCode() {
4769	>	int h = 0;
4770	>	for (E e : this)
4771	>	h += e.hashCode();
4772	>	return h;
4773	>	}
4774	>
4775	>	/**
4776	>	* Implements {@link Set#equals(Object)}.
4777	>	* @param o object to be compared for equality with this set
4778	>	* @return {@code true} if the specified object is equal to this set
4779	>	*/
4780	>	public final boolean equals(Object o) {
4781	>	Set<?> c;
4782	>	return ((o instanceof Set) &&
4783	>	((c = (Set<?>)o) == this ||
4784	>	(containsAll(c) && c.containsAll(this))));
4785	>	}
4786	>	}
4787	>
4788	>	/**
4789	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4790	>	* which additions may optionally be enabled by mapping to a
4791	>	* common value.  This class cannot be directly instantiated.
4792	>	* See {@link #keySet() keySet()},
4793	>	* {@link #keySet(Object) keySet(V)},
4794	>	* {@link #newKeySet() newKeySet()},
4795	>	* {@link #newKeySet(int) newKeySet(int)}.
4796	>	*/
4797	>	public static class KeySetView<K,V>
4798	>	extends CHMSetView<K,V,K>
4799	>	implements Set<K>, java.io.Serializable {
4800	>	private static final long serialVersionUID = 7249069246763182397L;
4801	>	private final V value;
4802	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4803	>	super(map);
4804	>	this.value = value;
4805	>	}
4806	>
4807	>	/**
4808	>	* Returns the default mapped value for additions,
4809	>	* or {@code null} if additions are not supported.
4810	>	*
4811	>	* @return the default mapped value for additions, or {@code null}
4812	>	* if not supported
4813	>	*/
4814	>	public V getMappedValue() { return value; }
4815	>
4816	>	/**
4817	>	* {@inheritDoc}
4818	>	* @throws NullPointerException if the specified key is null
4819	>	*/
4820	>	public boolean contains(Object o) { return map.containsKey(o); }
4821	>
4822	>	/**
4823	>	* Removes the key from this map view, by removing the key (and its
4824	>	* corresponding value) from the backing map.  This method does
4825	>	* nothing if the key is not in the map.
4826	>	*
4827	>	* @param  o the key to be removed from the backing map
4828	>	* @return {@code true} if the backing map contained the specified key
4829	>	* @throws NullPointerException if the specified key is null
4830	>	*/
4831	>	public boolean remove(Object o) { return map.remove(o) != null; }
4832	>
4833	>	/**
4834	>	* @return an iterator over the keys of the backing map
4835	>	*/
4836	>	public Iterator<K> iterator() { return new KeyIterator<K,V>(map); }
4837	>
4838	>	/**
4839	>	* Adds the specified key to this set view by mapping the key to
4840	>	* the default mapped value in the backing map, if defined.
4841	>	*
4842	>	* @param e key to be added
4843	>	* @return {@code true} if this set changed as a result of the call
4844	>	* @throws NullPointerException if the specified key is null
4845	>	* @throws UnsupportedOperationException if no default mapped value
4846	>	* for additions was provided
4847	>	*/
4848	>	public boolean add(K e) {
4849	>	V v;
4850	>	if ((v = value) == null)
4851	>	throw new UnsupportedOperationException();
4852	>	return map.internalPut(e, v, true) == null;
4853	>	}
4854	>
4855	>	/**
4856	>	* Adds all of the elements in the specified collection to this set,
4857	>	* as if by calling {@link #add} on each one.
4858	>	*
4859	>	* @param c the elements to be inserted into this set
4860	>	* @return {@code true} if this set changed as a result of the call
4861	>	* @throws NullPointerException if the collection or any of its
4862	>	* elements are {@code null}
4863	>	* @throws UnsupportedOperationException if no default mapped value
4864	>	* for additions was provided
4865	>	*/
4866	>	public boolean addAll(Collection<? extends K> c) {
4867	>	boolean added = false;
4868	>	V v;
4869	>	if ((v = value) == null)
4870	>	throw new UnsupportedOperationException();
4871	>	for (K e : c) {
4872	>	if (map.internalPut(e, v, true) == null)
4873	>	added = true;
4874	>	}
4875	>	return added;
4876	>	}
4877	>
4878	>	public Spliterator<K> spliterator() {
4879	>	return new KeyIterator<>(map, null);
4880	>	}
4881	>
4882	>	}
4883	>
4884	>	/**
4885	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4886	>	* values, in which additions are disabled. This class cannot be
4887	>	* directly instantiated. See {@link #values()}.
4888	>	*
4889	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
4890	>	* that will never throw {@link ConcurrentModificationException},
4891	>	* and guarantees to traverse elements as they existed upon
4892	>	* construction of the iterator, and may (but is not guaranteed to)
4893	>	* reflect any modifications subsequent to construction.
4894	>	*/
4895	>	public static final class ValuesView<K,V>
4896	>	extends CHMCollectionView<K,V,V>
4897	>	implements Collection<V>, java.io.Serializable {
4898	>	private static final long serialVersionUID = 2249069246763182397L;
4899	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4900	>	public final boolean contains(Object o) {
4901	>	return map.containsValue(o);
4902	>	}
4903	>	public final boolean remove(Object o) {
4904	>	if (o != null) {
4905	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4906	>	if (o.equals(it.next())) {
4907	>	it.remove();
4908	>	return true;
4909		}
4910		}
1420	–	} finally {
1421	–	seg.unlock();
4911		}
4912	+	return false;
4913		}
4914	<	s.writeObject(null);
4915	<	s.writeObject(null);
4914	>
4915	>	/**
4916	>	* @return an iterator over the values of the backing map
4917	>	*/
4918	>	public final Iterator<V> iterator() {
4919	>	return new ValueIterator<K,V>(map);
4920	>	}
4921	>
4922	>	/** Always throws {@link UnsupportedOperationException}. */
4923	>	public final boolean add(V e) {
4924	>	throw new UnsupportedOperationException();
4925	>	}
4926	>	/** Always throws {@link UnsupportedOperationException}. */
4927	>	public final boolean addAll(Collection<? extends V> c) {
4928	>	throw new UnsupportedOperationException();
4929	>	}
4930	>
4931	>	public Spliterator<V> spliterator() {
4932	>	return new ValueIterator<K,V>(map, null);
4933	>	}
4934	>
4935		}
4936
4937		/**
4938	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
4939	<	* stream (i.e., deserializes it).
4940	<	* @param s the stream
4938	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4939	>	* entries.  This class cannot be directly instantiated. See
4940	>	* {@link #entrySet()}.
4941		*/
4942	<	@SuppressWarnings("unchecked")
4943	<	private void readObject(java.io.ObjectInputStream s)
4944	<	throws java.io.IOException, ClassNotFoundException {
4945	<	s.defaultReadObject();
4942	>	public static final class EntrySetView<K,V>
4943	>	extends CHMSetView<K,V,Map.Entry<K,V>>
4944	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4945	>	private static final long serialVersionUID = 2249069246763182397L;
4946	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4947	>
4948	>	public final boolean contains(Object o) {
4949	>	Object k, v, r; Map.Entry<?,?> e;
4950	>	return ((o instanceof Map.Entry) &&
4951	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4952	>	(r = map.get(k)) != null &&
4953	>	(v = e.getValue()) != null &&
4954	>	(v == r || v.equals(r)));
4955	>	}
4956	>	public final boolean remove(Object o) {
4957	>	Object k, v; Map.Entry<?,?> e;
4958	>	return ((o instanceof Map.Entry) &&
4959	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4960	>	(v = e.getValue()) != null &&
4961	>	map.remove(k, v));
4962	>	}
4963
4964	<	// Re-initialize segments to be minimally sized, and let grow.
4965	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
4966	<	final Segment<K,V>[] segments = this.segments;
4967	<	for (int k = 0; k < segments.length; ++k) {
4968	<	Segment<K,V> seg = segments[k];
4969	<	if (seg != null) {
4970	<	seg.threshold = (int)(cap * seg.loadFactor);
4971	<	seg.table = (HashEntry<K,V>[]) new HashEntry<?,?>[cap];
4964	>	/**
4965	>	* @return an iterator over the entries of the backing map
4966	>	*/
4967	>	public final Iterator<Map.Entry<K,V>> iterator() {
4968	>	return new EntryIterator<K,V>(map);
4969	>	}
4970	>
4971	>	/**
4972	>	* Adds the specified mapping to this view.
4973	>	*
4974	>	* @param e mapping to be added
4975	>	* @return {@code true} if this set changed as a result of the call
4976	>	* @throws NullPointerException if the entry, its key, or its
4977	>	* value is null
4978	>	*/
4979	>	public final boolean add(Entry<K,V> e) {
4980	>	return map.internalPut(e.getKey(), e.getValue(), false) == null;
4981	>	}
4982	>	/**
4983	>	* Adds all of the mappings in the specified collection to this
4984	>	* set, as if by calling {@link #add(Map.Entry)} on each one.
4985	>	* @param c the mappings to be inserted into this set
4986	>	* @return {@code true} if this set changed as a result of the call
4987	>	* @throws NullPointerException if the collection or any of its
4988	>	* entries, keys, or values are null
4989	>	*/
4990	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
4991	>	boolean added = false;
4992	>	for (Entry<K,V> e : c) {
4993	>	if (add(e))
4994	>	added = true;
4995		}
4996	+	return added;
4997		}
4998
4999	<	// Read the keys and values, and put the mappings in the table
5000	<	for (;;) {
5001	<	K key = (K) s.readObject();
5002	<	V value = (V) s.readObject();
5003	<	if (key == null)
5004	<	break;
5005	<	put(key, value);
4999	>	public Spliterator<Map.Entry<K,V>> spliterator() {
5000	>	return new EntryIterator<K,V>(map, null);
5001	>	}
5002	>
5003	>	}
5004	>
5005	>	// ---------------------------------------------------------------------
5006	>
5007	>	/**
5008	>	* Predefined tasks for performing bulk parallel operations on
5009	>	* ConcurrentHashMaps. These tasks follow the forms and rules used
5010	>	* for bulk operations. Each method has the same name, but returns
5011	>	* a task rather than invoking it. These methods may be useful in
5012	>	* custom applications such as submitting a task without waiting
5013	>	* for completion, using a custom pool, or combining with other
5014	>	* tasks.
5015	>	*/
5016	>	public static class ForkJoinTasks {
5017	>	private ForkJoinTasks() {}
5018	>
5019	>	/**
5020	>	* Returns a task that when invoked, performs the given
5021	>	* action for each (key, value)
5022	>	*
5023	>	* @param map the map
5024	>	* @param action the action
5025	>	* @return the task
5026	>	*/
5027	>	public static <K,V> ForkJoinTask<Void> forEach
5028	>	(ConcurrentHashMap<K,V> map,
5029	>	BiConsumer<? super K, ? super V> action) {
5030	>	if (action == null) throw new NullPointerException();
5031	>	return new ForEachMappingTask<K,V>(map, null, -1, action);
5032	>	}
5033	>
5034	>	/**
5035	>	* Returns a task that when invoked, performs the given
5036	>	* action for each non-null transformation of each (key, value)
5037	>	*
5038	>	* @param map the map
5039	>	* @param transformer a function returning the transformation
5040	>	* for an element, or null if there is no transformation (in
5041	>	* which case the action is not applied)
5042	>	* @param action the action
5043	>	* @return the task
5044	>	*/
5045	>	public static <K,V,U> ForkJoinTask<Void> forEach
5046	>	(ConcurrentHashMap<K,V> map,
5047	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5048	>	Consumer<? super U> action) {
5049	>	if (transformer == null || action == null)
5050	>	throw new NullPointerException();
5051	>	return new ForEachTransformedMappingTask<K,V,U>
5052	>	(map, null, -1, transformer, action);
5053	>	}
5054	>
5055	>	/**
5056	>	* Returns a task that when invoked, returns a non-null result
5057	>	* from applying the given search function on each (key,
5058	>	* value), or null if none. Upon success, further element
5059	>	* processing is suppressed and the results of any other
5060	>	* parallel invocations of the search function are ignored.
5061	>	*
5062	>	* @param map the map
5063	>	* @param searchFunction a function returning a non-null
5064	>	* result on success, else null
5065	>	* @return the task
5066	>	*/
5067	>	public static <K,V,U> ForkJoinTask<U> search
5068	>	(ConcurrentHashMap<K,V> map,
5069	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
5070	>	if (searchFunction == null) throw new NullPointerException();
5071	>	return new SearchMappingsTask<K,V,U>
5072	>	(map, null, -1, searchFunction,
5073	>	new AtomicReference<U>());
5074	>	}
5075	>
5076	>	/**
5077	>	* Returns a task that when invoked, returns the result of
5078	>	* accumulating the given transformation of all (key, value) pairs
5079	>	* using the given reducer to combine values, or null if none.
5080	>	*
5081	>	* @param map the map
5082	>	* @param transformer a function returning the transformation
5083	>	* for an element, or null if there is no transformation (in
5084	>	* which case it is not combined)
5085	>	* @param reducer a commutative associative combining function
5086	>	* @return the task
5087	>	*/
5088	>	public static <K,V,U> ForkJoinTask<U> reduce
5089	>	(ConcurrentHashMap<K,V> map,
5090	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5091	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5092	>	if (transformer == null || reducer == null)
5093	>	throw new NullPointerException();
5094	>	return new MapReduceMappingsTask<K,V,U>
5095	>	(map, null, -1, null, transformer, reducer);
5096	>	}
5097	>
5098	>	/**
5099	>	* Returns a task that when invoked, returns the result of
5100	>	* accumulating the given transformation of all (key, value) pairs
5101	>	* using the given reducer to combine values, and the given
5102	>	* basis as an identity value.
5103	>	*
5104	>	* @param map the map
5105	>	* @param transformer a function returning the transformation
5106	>	* for an element
5107	>	* @param basis the identity (initial default value) for the reduction
5108	>	* @param reducer a commutative associative combining function
5109	>	* @return the task
5110	>	*/
5111	>	public static <K,V> ForkJoinTask<Double> reduceToDouble
5112	>	(ConcurrentHashMap<K,V> map,
5113	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5114	>	double basis,
5115	>	DoubleBinaryOperator reducer) {
5116	>	if (transformer == null || reducer == null)
5117	>	throw new NullPointerException();
5118	>	return new MapReduceMappingsToDoubleTask<K,V>
5119	>	(map, null, -1, null, transformer, basis, reducer);
5120	>	}
5121	>
5122	>	/**
5123	>	* Returns a task that when invoked, returns the result of
5124	>	* accumulating the given transformation of all (key, value) pairs
5125	>	* using the given reducer to combine values, and the given
5126	>	* basis as an identity value.
5127	>	*
5128	>	* @param map the map
5129	>	* @param transformer a function returning the transformation
5130	>	* for an element
5131	>	* @param basis the identity (initial default value) for the reduction
5132	>	* @param reducer a commutative associative combining function
5133	>	* @return the task
5134	>	*/
5135	>	public static <K,V> ForkJoinTask<Long> reduceToLong
5136	>	(ConcurrentHashMap<K,V> map,
5137	>	ToLongBiFunction<? super K, ? super V> transformer,
5138	>	long basis,
5139	>	LongBinaryOperator reducer) {
5140	>	if (transformer == null || reducer == null)
5141	>	throw new NullPointerException();
5142	>	return new MapReduceMappingsToLongTask<K,V>
5143	>	(map, null, -1, null, transformer, basis, reducer);
5144	>	}
5145	>
5146	>	/**
5147	>	* Returns a task that when invoked, returns the result of
5148	>	* accumulating the given transformation of all (key, value) pairs
5149	>	* using the given reducer to combine values, and the given
5150	>	* basis as an identity value.
5151	>	*
5152	>	* @param map the map
5153	>	* @param transformer a function returning the transformation
5154	>	* for an element
5155	>	* @param basis the identity (initial default value) for the reduction
5156	>	* @param reducer a commutative associative combining function
5157	>	* @return the task
5158	>	*/
5159	>	public static <K,V> ForkJoinTask<Integer> reduceToInt
5160	>	(ConcurrentHashMap<K,V> map,
5161	>	ToIntBiFunction<? super K, ? super V> transformer,
5162	>	int basis,
5163	>	IntBinaryOperator reducer) {
5164	>	if (transformer == null || reducer == null)
5165	>	throw new NullPointerException();
5166	>	return new MapReduceMappingsToIntTask<K,V>
5167	>	(map, null, -1, null, transformer, basis, reducer);
5168	>	}
5169	>
5170	>	/**
5171	>	* Returns a task that when invoked, performs the given action
5172	>	* for each key.
5173	>	*
5174	>	* @param map the map
5175	>	* @param action the action
5176	>	* @return the task
5177	>	*/
5178	>	public static <K,V> ForkJoinTask<Void> forEachKey
5179	>	(ConcurrentHashMap<K,V> map,
5180	>	Consumer<? super K> action) {
5181	>	if (action == null) throw new NullPointerException();
5182	>	return new ForEachKeyTask<K,V>(map, null, -1, action);
5183	>	}
5184	>
5185	>	/**
5186	>	* Returns a task that when invoked, performs the given action
5187	>	* for each non-null transformation of each key.
5188	>	*
5189	>	* @param map the map
5190	>	* @param transformer a function returning the transformation
5191	>	* for an element, or null if there is no transformation (in
5192	>	* which case the action is not applied)
5193	>	* @param action the action
5194	>	* @return the task
5195	>	*/
5196	>	public static <K,V,U> ForkJoinTask<Void> forEachKey
5197	>	(ConcurrentHashMap<K,V> map,
5198	>	Function<? super K, ? extends U> transformer,
5199	>	Consumer<? super U> action) {
5200	>	if (transformer == null || action == null)
5201	>	throw new NullPointerException();
5202	>	return new ForEachTransformedKeyTask<K,V,U>
5203	>	(map, null, -1, transformer, action);
5204	>	}
5205	>
5206	>	/**
5207	>	* Returns a task that when invoked, returns a non-null result
5208	>	* from applying the given search function on each key, or
5209	>	* null if none.  Upon success, further element processing is
5210	>	* suppressed and the results of any other parallel
5211	>	* invocations of the search function are ignored.
5212	>	*
5213	>	* @param map the map
5214	>	* @param searchFunction a function returning a non-null
5215	>	* result on success, else null
5216	>	* @return the task
5217	>	*/
5218	>	public static <K,V,U> ForkJoinTask<U> searchKeys
5219	>	(ConcurrentHashMap<K,V> map,
5220	>	Function<? super K, ? extends U> searchFunction) {
5221	>	if (searchFunction == null) throw new NullPointerException();
5222	>	return new SearchKeysTask<K,V,U>
5223	>	(map, null, -1, searchFunction,
5224	>	new AtomicReference<U>());
5225	>	}
5226	>
5227	>	/**
5228	>	* Returns a task that when invoked, returns the result of
5229	>	* accumulating all keys using the given reducer to combine
5230	>	* values, or null if none.
5231	>	*
5232	>	* @param map the map
5233	>	* @param reducer a commutative associative combining function
5234	>	* @return the task
5235	>	*/
5236	>	public static <K,V> ForkJoinTask<K> reduceKeys
5237	>	(ConcurrentHashMap<K,V> map,
5238	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5239	>	if (reducer == null) throw new NullPointerException();
5240	>	return new ReduceKeysTask<K,V>
5241	>	(map, null, -1, null, reducer);
5242	>	}
5243	>
5244	>	/**
5245	>	* Returns a task that when invoked, returns the result of
5246	>	* accumulating the given transformation of all keys using the given
5247	>	* reducer to combine values, or null if none.
5248	>	*
5249	>	* @param map the map
5250	>	* @param transformer a function returning the transformation
5251	>	* for an element, or null if there is no transformation (in
5252	>	* which case it is not combined)
5253	>	* @param reducer a commutative associative combining function
5254	>	* @return the task
5255	>	*/
5256	>	public static <K,V,U> ForkJoinTask<U> reduceKeys
5257	>	(ConcurrentHashMap<K,V> map,
5258	>	Function<? super K, ? extends U> transformer,
5259	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5260	>	if (transformer == null || reducer == null)
5261	>	throw new NullPointerException();
5262	>	return new MapReduceKeysTask<K,V,U>
5263	>	(map, null, -1, null, transformer, reducer);
5264	>	}
5265	>
5266	>	/**
5267	>	* Returns a task that when invoked, returns the result of
5268	>	* accumulating the given transformation of all keys using the given
5269	>	* reducer to combine values, and the given basis as an
5270	>	* identity value.
5271	>	*
5272	>	* @param map the map
5273	>	* @param transformer a function returning the transformation
5274	>	* for an element
5275	>	* @param basis the identity (initial default value) for the reduction
5276	>	* @param reducer a commutative associative combining function
5277	>	* @return the task
5278	>	*/
5279	>	public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
5280	>	(ConcurrentHashMap<K,V> map,
5281	>	ToDoubleFunction<? super K> transformer,
5282	>	double basis,
5283	>	DoubleBinaryOperator reducer) {
5284	>	if (transformer == null || reducer == null)
5285	>	throw new NullPointerException();
5286	>	return new MapReduceKeysToDoubleTask<K,V>
5287	>	(map, null, -1, null, transformer, basis, reducer);
5288	>	}
5289	>
5290	>	/**
5291	>	* Returns a task that when invoked, returns the result of
5292	>	* accumulating the given transformation of all keys using the given
5293	>	* reducer to combine values, and the given basis as an
5294	>	* identity value.
5295	>	*
5296	>	* @param map the map
5297	>	* @param transformer a function returning the transformation
5298	>	* for an element
5299	>	* @param basis the identity (initial default value) for the reduction
5300	>	* @param reducer a commutative associative combining function
5301	>	* @return the task
5302	>	*/
5303	>	public static <K,V> ForkJoinTask<Long> reduceKeysToLong
5304	>	(ConcurrentHashMap<K,V> map,
5305	>	ToLongFunction<? super K> transformer,
5306	>	long basis,
5307	>	LongBinaryOperator reducer) {
5308	>	if (transformer == null || reducer == null)
5309	>	throw new NullPointerException();
5310	>	return new MapReduceKeysToLongTask<K,V>
5311	>	(map, null, -1, null, transformer, basis, reducer);
5312	>	}
5313	>
5314	>	/**
5315	>	* Returns a task that when invoked, returns the result of
5316	>	* accumulating the given transformation of all keys using the given
5317	>	* reducer to combine values, and the given basis as an
5318	>	* identity value.
5319	>	*
5320	>	* @param map the map
5321	>	* @param transformer a function returning the transformation
5322	>	* for an element
5323	>	* @param basis the identity (initial default value) for the reduction
5324	>	* @param reducer a commutative associative combining function
5325	>	* @return the task
5326	>	*/
5327	>	public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
5328	>	(ConcurrentHashMap<K,V> map,
5329	>	ToIntFunction<? super K> transformer,
5330	>	int basis,
5331	>	IntBinaryOperator reducer) {
5332	>	if (transformer == null || reducer == null)
5333	>	throw new NullPointerException();
5334	>	return new MapReduceKeysToIntTask<K,V>
5335	>	(map, null, -1, null, transformer, basis, reducer);
5336	>	}
5337	>
5338	>	/**
5339	>	* Returns a task that when invoked, performs the given action
5340	>	* for each value.
5341	>	*
5342	>	* @param map the map
5343	>	* @param action the action
5344	>	* @return the task
5345	>	*/
5346	>	public static <K,V> ForkJoinTask<Void> forEachValue
5347	>	(ConcurrentHashMap<K,V> map,
5348	>	Consumer<? super V> action) {
5349	>	if (action == null) throw new NullPointerException();
5350	>	return new ForEachValueTask<K,V>(map, null, -1, action);
5351	>	}
5352	>
5353	>	/**
5354	>	* Returns a task that when invoked, performs the given action
5355	>	* for each non-null transformation of each value.
5356	>	*
5357	>	* @param map the map
5358	>	* @param transformer a function returning the transformation
5359	>	* for an element, or null if there is no transformation (in
5360	>	* which case the action is not applied)
5361	>	* @param action the action
5362	>	* @return the task
5363	>	*/
5364	>	public static <K,V,U> ForkJoinTask<Void> forEachValue
5365	>	(ConcurrentHashMap<K,V> map,
5366	>	Function<? super V, ? extends U> transformer,
5367	>	Consumer<? super U> action) {
5368	>	if (transformer == null || action == null)
5369	>	throw new NullPointerException();
5370	>	return new ForEachTransformedValueTask<K,V,U>
5371	>	(map, null, -1, transformer, action);
5372	>	}
5373	>
5374	>	/**
5375	>	* Returns a task that when invoked, returns a non-null result
5376	>	* from applying the given search function on each value, or
5377	>	* null if none.  Upon success, further element processing is
5378	>	* suppressed and the results of any other parallel
5379	>	* invocations of the search function are ignored.
5380	>	*
5381	>	* @param map the map
5382	>	* @param searchFunction a function returning a non-null
5383	>	* result on success, else null
5384	>	* @return the task
5385	>	*/
5386	>	public static <K,V,U> ForkJoinTask<U> searchValues
5387	>	(ConcurrentHashMap<K,V> map,
5388	>	Function<? super V, ? extends U> searchFunction) {
5389	>	if (searchFunction == null) throw new NullPointerException();
5390	>	return new SearchValuesTask<K,V,U>
5391	>	(map, null, -1, searchFunction,
5392	>	new AtomicReference<U>());
5393	>	}
5394	>
5395	>	/**
5396	>	* Returns a task that when invoked, returns the result of
5397	>	* accumulating all values using the given reducer to combine
5398	>	* values, or null if none.
5399	>	*
5400	>	* @param map the map
5401	>	* @param reducer a commutative associative combining function
5402	>	* @return the task
5403	>	*/
5404	>	public static <K,V> ForkJoinTask<V> reduceValues
5405	>	(ConcurrentHashMap<K,V> map,
5406	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5407	>	if (reducer == null) throw new NullPointerException();
5408	>	return new ReduceValuesTask<K,V>
5409	>	(map, null, -1, null, reducer);
5410	>	}
5411	>
5412	>	/**
5413	>	* Returns a task that when invoked, returns the result of
5414	>	* accumulating the given transformation of all values using the
5415	>	* given reducer to combine values, or null if none.
5416	>	*
5417	>	* @param map the map
5418	>	* @param transformer a function returning the transformation
5419	>	* for an element, or null if there is no transformation (in
5420	>	* which case it is not combined)
5421	>	* @param reducer a commutative associative combining function
5422	>	* @return the task
5423	>	*/
5424	>	public static <K,V,U> ForkJoinTask<U> reduceValues
5425	>	(ConcurrentHashMap<K,V> map,
5426	>	Function<? super V, ? extends U> transformer,
5427	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5428	>	if (transformer == null || reducer == null)
5429	>	throw new NullPointerException();
5430	>	return new MapReduceValuesTask<K,V,U>
5431	>	(map, null, -1, null, transformer, reducer);
5432	>	}
5433	>
5434	>	/**
5435	>	* Returns a task that when invoked, returns the result of
5436	>	* accumulating the given transformation of all values using the
5437	>	* given reducer to combine values, and the given basis as an
5438	>	* identity value.
5439	>	*
5440	>	* @param map the map
5441	>	* @param transformer a function returning the transformation
5442	>	* for an element
5443	>	* @param basis the identity (initial default value) for the reduction
5444	>	* @param reducer a commutative associative combining function
5445	>	* @return the task
5446	>	*/
5447	>	public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
5448	>	(ConcurrentHashMap<K,V> map,
5449	>	ToDoubleFunction<? super V> transformer,
5450	>	double basis,
5451	>	DoubleBinaryOperator reducer) {
5452	>	if (transformer == null || reducer == null)
5453	>	throw new NullPointerException();
5454	>	return new MapReduceValuesToDoubleTask<K,V>
5455	>	(map, null, -1, null, transformer, basis, reducer);
5456	>	}
5457	>
5458	>	/**
5459	>	* Returns a task that when invoked, returns the result of
5460	>	* accumulating the given transformation of all values using the
5461	>	* given reducer to combine values, and the given basis as an
5462	>	* identity value.
5463	>	*
5464	>	* @param map the map
5465	>	* @param transformer a function returning the transformation
5466	>	* for an element
5467	>	* @param basis the identity (initial default value) for the reduction
5468	>	* @param reducer a commutative associative combining function
5469	>	* @return the task
5470	>	*/
5471	>	public static <K,V> ForkJoinTask<Long> reduceValuesToLong
5472	>	(ConcurrentHashMap<K,V> map,
5473	>	ToLongFunction<? super V> transformer,
5474	>	long basis,
5475	>	LongBinaryOperator reducer) {
5476	>	if (transformer == null || reducer == null)
5477	>	throw new NullPointerException();
5478	>	return new MapReduceValuesToLongTask<K,V>
5479	>	(map, null, -1, null, transformer, basis, reducer);
5480	>	}
5481	>
5482	>	/**
5483	>	* Returns a task that when invoked, returns the result of
5484	>	* accumulating the given transformation of all values using the
5485	>	* given reducer to combine values, and the given basis as an
5486	>	* identity value.
5487	>	*
5488	>	* @param map the map
5489	>	* @param transformer a function returning the transformation
5490	>	* for an element
5491	>	* @param basis the identity (initial default value) for the reduction
5492	>	* @param reducer a commutative associative combining function
5493	>	* @return the task
5494	>	*/
5495	>	public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
5496	>	(ConcurrentHashMap<K,V> map,
5497	>	ToIntFunction<? super V> transformer,
5498	>	int basis,
5499	>	IntBinaryOperator reducer) {
5500	>	if (transformer == null || reducer == null)
5501	>	throw new NullPointerException();
5502	>	return new MapReduceValuesToIntTask<K,V>
5503	>	(map, null, -1, null, transformer, basis, reducer);
5504	>	}
5505	>
5506	>	/**
5507	>	* Returns a task that when invoked, perform the given action
5508	>	* for each entry.
5509	>	*
5510	>	* @param map the map
5511	>	* @param action the action
5512	>	* @return the task
5513	>	*/
5514	>	public static <K,V> ForkJoinTask<Void> forEachEntry
5515	>	(ConcurrentHashMap<K,V> map,
5516	>	Consumer<? super Map.Entry<K,V>> action) {
5517	>	if (action == null) throw new NullPointerException();
5518	>	return new ForEachEntryTask<K,V>(map, null, -1, action);
5519	>	}
5520	>
5521	>	/**
5522	>	* Returns a task that when invoked, perform the given action
5523	>	* for each non-null transformation of each entry.
5524	>	*
5525	>	* @param map the map
5526	>	* @param transformer a function returning the transformation
5527	>	* for an element, or null if there is no transformation (in
5528	>	* which case the action is not applied)
5529	>	* @param action the action
5530	>	* @return the task
5531	>	*/
5532	>	public static <K,V,U> ForkJoinTask<Void> forEachEntry
5533	>	(ConcurrentHashMap<K,V> map,
5534	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5535	>	Consumer<? super U> action) {
5536	>	if (transformer == null || action == null)
5537	>	throw new NullPointerException();
5538	>	return new ForEachTransformedEntryTask<K,V,U>
5539	>	(map, null, -1, transformer, action);
5540	>	}
5541	>
5542	>	/**
5543	>	* Returns a task that when invoked, returns a non-null result
5544	>	* from applying the given search function on each entry, or
5545	>	* null if none.  Upon success, further element processing is
5546	>	* suppressed and the results of any other parallel
5547	>	* invocations of the search function are ignored.
5548	>	*
5549	>	* @param map the map
5550	>	* @param searchFunction a function returning a non-null
5551	>	* result on success, else null
5552	>	* @return the task
5553	>	*/
5554	>	public static <K,V,U> ForkJoinTask<U> searchEntries
5555	>	(ConcurrentHashMap<K,V> map,
5556	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
5557	>	if (searchFunction == null) throw new NullPointerException();
5558	>	return new SearchEntriesTask<K,V,U>
5559	>	(map, null, -1, searchFunction,
5560	>	new AtomicReference<U>());
5561	>	}
5562	>
5563	>	/**
5564	>	* Returns a task that when invoked, returns the result of
5565	>	* accumulating all entries using the given reducer to combine
5566	>	* values, or null if none.
5567	>	*
5568	>	* @param map the map
5569	>	* @param reducer a commutative associative combining function
5570	>	* @return the task
5571	>	*/
5572	>	public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
5573	>	(ConcurrentHashMap<K,V> map,
5574	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5575	>	if (reducer == null) throw new NullPointerException();
5576	>	return new ReduceEntriesTask<K,V>
5577	>	(map, null, -1, null, reducer);
5578	>	}
5579	>
5580	>	/**
5581	>	* Returns a task that when invoked, returns the result of
5582	>	* accumulating the given transformation of all entries using the
5583	>	* given reducer to combine values, or null if none.
5584	>	*
5585	>	* @param map the map
5586	>	* @param transformer a function returning the transformation
5587	>	* for an element, or null if there is no transformation (in
5588	>	* which case it is not combined)
5589	>	* @param reducer a commutative associative combining function
5590	>	* @return the task
5591	>	*/
5592	>	public static <K,V,U> ForkJoinTask<U> reduceEntries
5593	>	(ConcurrentHashMap<K,V> map,
5594	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5595	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5596	>	if (transformer == null || reducer == null)
5597	>	throw new NullPointerException();
5598	>	return new MapReduceEntriesTask<K,V,U>
5599	>	(map, null, -1, null, transformer, reducer);
5600	>	}
5601	>
5602	>	/**
5603	>	* Returns a task that when invoked, returns the result of
5604	>	* accumulating the given transformation of all entries using the
5605	>	* given reducer to combine values, and the given basis as an
5606	>	* identity value.
5607	>	*
5608	>	* @param map the map
5609	>	* @param transformer a function returning the transformation
5610	>	* for an element
5611	>	* @param basis the identity (initial default value) for the reduction
5612	>	* @param reducer a commutative associative combining function
5613	>	* @return the task
5614	>	*/
5615	>	public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
5616	>	(ConcurrentHashMap<K,V> map,
5617	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5618	>	double basis,
5619	>	DoubleBinaryOperator reducer) {
5620	>	if (transformer == null || reducer == null)
5621	>	throw new NullPointerException();
5622	>	return new MapReduceEntriesToDoubleTask<K,V>
5623	>	(map, null, -1, null, transformer, basis, reducer);
5624	>	}
5625	>
5626	>	/**
5627	>	* Returns a task that when invoked, returns the result of
5628	>	* accumulating the given transformation of all entries using the
5629	>	* given reducer to combine values, and the given basis as an
5630	>	* identity value.
5631	>	*
5632	>	* @param map the map
5633	>	* @param transformer a function returning the transformation
5634	>	* for an element
5635	>	* @param basis the identity (initial default value) for the reduction
5636	>	* @param reducer a commutative associative combining function
5637	>	* @return the task
5638	>	*/
5639	>	public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
5640	>	(ConcurrentHashMap<K,V> map,
5641	>	ToLongFunction<Map.Entry<K,V>> transformer,
5642	>	long basis,
5643	>	LongBinaryOperator reducer) {
5644	>	if (transformer == null || reducer == null)
5645	>	throw new NullPointerException();
5646	>	return new MapReduceEntriesToLongTask<K,V>
5647	>	(map, null, -1, null, transformer, basis, reducer);
5648	>	}
5649	>
5650	>	/**
5651	>	* Returns a task that when invoked, returns the result of
5652	>	* accumulating the given transformation of all entries using the
5653	>	* given reducer to combine values, and the given basis as an
5654	>	* identity value.
5655	>	*
5656	>	* @param map the map
5657	>	* @param transformer a function returning the transformation
5658	>	* for an element
5659	>	* @param basis the identity (initial default value) for the reduction
5660	>	* @param reducer a commutative associative combining function
5661	>	* @return the task
5662	>	*/
5663	>	public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
5664	>	(ConcurrentHashMap<K,V> map,
5665	>	ToIntFunction<Map.Entry<K,V>> transformer,
5666	>	int basis,
5667	>	IntBinaryOperator reducer) {
5668	>	if (transformer == null || reducer == null)
5669	>	throw new NullPointerException();
5670	>	return new MapReduceEntriesToIntTask<K,V>
5671	>	(map, null, -1, null, transformer, basis, reducer);
5672	>	}
5673	>	}
5674	>
5675	>	// -------------------------------------------------------
5676	>
5677	>	/*
5678	>	* Task classes. Coded in a regular but ugly format/style to
5679	>	* simplify checks that each variant differs in the right way from
5680	>	* others. The null screenings exist because compilers cannot tell
5681	>	* that we've already null-checked task arguments, so we force
5682	>	* simplest hoisted bypass to help avoid convoluted traps.
5683	>	*/
5684	>
5685	>	@SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
5686	>	extends Traverser<K,V,Void> {
5687	>	final Consumer<? super K> action;
5688	>	ForEachKeyTask
5689	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5690	>	Consumer<? super K> action) {
5691	>	super(m, p, b);
5692	>	this.action = action;
5693	>	}
5694	>	public final void compute() {
5695	>	final Consumer<? super K> action;
5696	>	if ((action = this.action) != null) {
5697	>	for (int b; (b = preSplit()) > 0;)
5698	>	new ForEachKeyTask<K,V>(map, this, b, action).fork();
5699	>	forEachKey(action);
5700	>	propagateCompletion();
5701	>	}
5702	>	}
5703	>	}
5704	>
5705	>	@SuppressWarnings("serial") static final class ForEachValueTask<K,V>
5706	>	extends Traverser<K,V,Void> {
5707	>	final Consumer<? super V> action;
5708	>	ForEachValueTask
5709	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5710	>	Consumer<? super V> action) {
5711	>	super(m, p, b);
5712	>	this.action = action;
5713	>	}
5714	>	public final void compute() {
5715	>	final Consumer<? super V> action;
5716	>	if ((action = this.action) != null) {
5717	>	for (int b; (b = preSplit()) > 0;)
5718	>	new ForEachValueTask<K,V>(map, this, b, action).fork();
5719	>	forEachValue(action);
5720	>	propagateCompletion();
5721	>	}
5722	>	}
5723	>	}
5724	>
5725	>	@SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5726	>	extends Traverser<K,V,Void> {
5727	>	final Consumer<? super Entry<K,V>> action;
5728	>	ForEachEntryTask
5729	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5730	>	Consumer<? super Entry<K,V>> action) {
5731	>	super(m, p, b);
5732	>	this.action = action;
5733	>	}
5734	>	public final void compute() {
5735	>	final Consumer<? super Entry<K,V>> action;
5736	>	if ((action = this.action) != null) {
5737	>	for (int b; (b = preSplit()) > 0;)
5738	>	new ForEachEntryTask<K,V>(map, this, b, action).fork();
5739	>	V v;
5740	>	while ((v = advanceValue()) != null)
5741	>	action.accept(entryFor(nextKey, v));
5742	>	propagateCompletion();
5743	>	}
5744	>	}
5745	>	}
5746	>
5747	>	@SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5748	>	extends Traverser<K,V,Void> {
5749	>	final BiConsumer<? super K, ? super V> action;
5750	>	ForEachMappingTask
5751	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5752	>	BiConsumer<? super K,? super V> action) {
5753	>	super(m, p, b);
5754	>	this.action = action;
5755	>	}
5756	>	public final void compute() {
5757	>	final BiConsumer<? super K, ? super V> action;
5758	>	if ((action = this.action) != null) {
5759	>	for (int b; (b = preSplit()) > 0;)
5760	>	new ForEachMappingTask<K,V>(map, this, b, action).fork();
5761	>	V v;
5762	>	while ((v = advanceValue()) != null)
5763	>	action.accept(nextKey, v);
5764	>	propagateCompletion();
5765	>	}
5766	>	}
5767	>	}
5768	>
5769	>	@SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5770	>	extends Traverser<K,V,Void> {
5771	>	final Function<? super K, ? extends U> transformer;
5772	>	final Consumer<? super U> action;
5773	>	ForEachTransformedKeyTask
5774	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5775	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5776	>	super(m, p, b);
5777	>	this.transformer = transformer; this.action = action;
5778	>	}
5779	>	public final void compute() {
5780	>	final Function<? super K, ? extends U> transformer;
5781	>	final Consumer<? super U> action;
5782	>	if ((transformer = this.transformer) != null &&
5783	>	(action = this.action) != null) {
5784	>	for (int b; (b = preSplit()) > 0;)
5785	>	new ForEachTransformedKeyTask<K,V,U>
5786	>	(map, this, b, transformer, action).fork();
5787	>	K k; U u;
5788	>	while ((k = advanceKey()) != null) {
5789	>	if ((u = transformer.apply(k)) != null)
5790	>	action.accept(u);
5791	>	}
5792	>	propagateCompletion();
5793	>	}
5794	>	}
5795	>	}
5796	>
5797	>	@SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5798	>	extends Traverser<K,V,Void> {
5799	>	final Function<? super V, ? extends U> transformer;
5800	>	final Consumer<? super U> action;
5801	>	ForEachTransformedValueTask
5802	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5803	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5804	>	super(m, p, b);
5805	>	this.transformer = transformer; this.action = action;
5806	>	}
5807	>	public final void compute() {
5808	>	final Function<? super V, ? extends U> transformer;
5809	>	final Consumer<? super U> action;
5810	>	if ((transformer = this.transformer) != null &&
5811	>	(action = this.action) != null) {
5812	>	for (int b; (b = preSplit()) > 0;)
5813	>	new ForEachTransformedValueTask<K,V,U>
5814	>	(map, this, b, transformer, action).fork();
5815	>	V v; U u;
5816	>	while ((v = advanceValue()) != null) {
5817	>	if ((u = transformer.apply(v)) != null)
5818	>	action.accept(u);
5819	>	}
5820	>	propagateCompletion();
5821	>	}
5822	>	}
5823	>	}
5824	>
5825	>	@SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5826	>	extends Traverser<K,V,Void> {
5827	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5828	>	final Consumer<? super U> action;
5829	>	ForEachTransformedEntryTask
5830	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5831	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5832	>	super(m, p, b);
5833	>	this.transformer = transformer; this.action = action;
5834	>	}
5835	>	public final void compute() {
5836	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5837	>	final Consumer<? super U> action;
5838	>	if ((transformer = this.transformer) != null &&
5839	>	(action = this.action) != null) {
5840	>	for (int b; (b = preSplit()) > 0;)
5841	>	new ForEachTransformedEntryTask<K,V,U>
5842	>	(map, this, b, transformer, action).fork();
5843	>	V v; U u;
5844	>	while ((v = advanceValue()) != null) {
5845	>	if ((u = transformer.apply(entryFor(nextKey,
5846	>	v))) != null)
5847	>	action.accept(u);
5848	>	}
5849	>	propagateCompletion();
5850	>	}
5851	>	}
5852	>	}
5853	>
5854	>	@SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5855	>	extends Traverser<K,V,Void> {
5856	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5857	>	final Consumer<? super U> action;
5858	>	ForEachTransformedMappingTask
5859	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5860	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5861	>	Consumer<? super U> action) {
5862	>	super(m, p, b);
5863	>	this.transformer = transformer; this.action = action;
5864	>	}
5865	>	public final void compute() {
5866	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5867	>	final Consumer<? super U> action;
5868	>	if ((transformer = this.transformer) != null &&
5869	>	(action = this.action) != null) {
5870	>	for (int b; (b = preSplit()) > 0;)
5871	>	new ForEachTransformedMappingTask<K,V,U>
5872	>	(map, this, b, transformer, action).fork();
5873	>	V v; U u;
5874	>	while ((v = advanceValue()) != null) {
5875	>	if ((u = transformer.apply(nextKey, v)) != null)
5876	>	action.accept(u);
5877	>	}
5878	>	propagateCompletion();
5879	>	}
5880	>	}
5881	>	}
5882	>
5883	>	@SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5884	>	extends Traverser<K,V,U> {
5885	>	final Function<? super K, ? extends U> searchFunction;
5886	>	final AtomicReference<U> result;
5887	>	SearchKeysTask
5888	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5889	>	Function<? super K, ? extends U> searchFunction,
5890	>	AtomicReference<U> result) {
5891	>	super(m, p, b);
5892	>	this.searchFunction = searchFunction; this.result = result;
5893	>	}
5894	>	public final U getRawResult() { return result.get(); }
5895	>	public final void compute() {
5896	>	final Function<? super K, ? extends U> searchFunction;
5897	>	final AtomicReference<U> result;
5898	>	if ((searchFunction = this.searchFunction) != null &&
5899	>	(result = this.result) != null) {
5900	>	for (int b;;) {
5901	>	if (result.get() != null)
5902	>	return;
5903	>	if ((b = preSplit()) <= 0)
5904	>	break;
5905	>	new SearchKeysTask<K,V,U>
5906	>	(map, this, b, searchFunction, result).fork();
5907	>	}
5908	>	while (result.get() == null) {
5909	>	K k; U u;
5910	>	if ((k = advanceKey()) == null) {
5911	>	propagateCompletion();
5912	>	break;
5913	>	}
5914	>	if ((u = searchFunction.apply(k)) != null) {
5915	>	if (result.compareAndSet(null, u))
5916	>	quietlyCompleteRoot();
5917	>	break;
5918	>	}
5919	>	}
5920	>	}
5921	>	}
5922	>	}
5923	>
5924	>	@SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5925	>	extends Traverser<K,V,U> {
5926	>	final Function<? super V, ? extends U> searchFunction;
5927	>	final AtomicReference<U> result;
5928	>	SearchValuesTask
5929	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5930	>	Function<? super V, ? extends U> searchFunction,
5931	>	AtomicReference<U> result) {
5932	>	super(m, p, b);
5933	>	this.searchFunction = searchFunction; this.result = result;
5934	>	}
5935	>	public final U getRawResult() { return result.get(); }
5936	>	public final void compute() {
5937	>	final Function<? super V, ? extends U> searchFunction;
5938	>	final AtomicReference<U> result;
5939	>	if ((searchFunction = this.searchFunction) != null &&
5940	>	(result = this.result) != null) {
5941	>	for (int b;;) {
5942	>	if (result.get() != null)
5943	>	return;
5944	>	if ((b = preSplit()) <= 0)
5945	>	break;
5946	>	new SearchValuesTask<K,V,U>
5947	>	(map, this, b, searchFunction, result).fork();
5948	>	}
5949	>	while (result.get() == null) {
5950	>	V v; U u;
5951	>	if ((v = advanceValue()) == null) {
5952	>	propagateCompletion();
5953	>	break;
5954	>	}
5955	>	if ((u = searchFunction.apply(v)) != null) {
5956	>	if (result.compareAndSet(null, u))
5957	>	quietlyCompleteRoot();
5958	>	break;
5959	>	}
5960	>	}
5961	>	}
5962	>	}
5963	>	}
5964	>
5965	>	@SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5966	>	extends Traverser<K,V,U> {
5967	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5968	>	final AtomicReference<U> result;
5969	>	SearchEntriesTask
5970	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5971	>	Function<Entry<K,V>, ? extends U> searchFunction,
5972	>	AtomicReference<U> result) {
5973	>	super(m, p, b);
5974	>	this.searchFunction = searchFunction; this.result = result;
5975	>	}
5976	>	public final U getRawResult() { return result.get(); }
5977	>	public final void compute() {
5978	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5979	>	final AtomicReference<U> result;
5980	>	if ((searchFunction = this.searchFunction) != null &&
5981	>	(result = this.result) != null) {
5982	>	for (int b;;) {
5983	>	if (result.get() != null)
5984	>	return;
5985	>	if ((b = preSplit()) <= 0)
5986	>	break;
5987	>	new SearchEntriesTask<K,V,U>
5988	>	(map, this, b, searchFunction, result).fork();
5989	>	}
5990	>	while (result.get() == null) {
5991	>	V v; U u;
5992	>	if ((v = advanceValue()) == null) {
5993	>	propagateCompletion();
5994	>	break;
5995	>	}
5996	>	if ((u = searchFunction.apply(entryFor(nextKey,
5997	>	v))) != null) {
5998	>	if (result.compareAndSet(null, u))
5999	>	quietlyCompleteRoot();
6000	>	return;
6001	>	}
6002	>	}
6003	>	}
6004	>	}
6005	>	}
6006	>
6007	>	@SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
6008	>	extends Traverser<K,V,U> {
6009	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
6010	>	final AtomicReference<U> result;
6011	>	SearchMappingsTask
6012	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6013	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
6014	>	AtomicReference<U> result) {
6015	>	super(m, p, b);
6016	>	this.searchFunction = searchFunction; this.result = result;
6017	>	}
6018	>	public final U getRawResult() { return result.get(); }
6019	>	public final void compute() {
6020	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
6021	>	final AtomicReference<U> result;
6022	>	if ((searchFunction = this.searchFunction) != null &&
6023	>	(result = this.result) != null) {
6024	>	for (int b;;) {
6025	>	if (result.get() != null)
6026	>	return;
6027	>	if ((b = preSplit()) <= 0)
6028	>	break;
6029	>	new SearchMappingsTask<K,V,U>
6030	>	(map, this, b, searchFunction, result).fork();
6031	>	}
6032	>	while (result.get() == null) {
6033	>	V v; U u;
6034	>	if ((v = advanceValue()) == null) {
6035	>	propagateCompletion();
6036	>	break;
6037	>	}
6038	>	if ((u = searchFunction.apply(nextKey, v)) != null) {
6039	>	if (result.compareAndSet(null, u))
6040	>	quietlyCompleteRoot();
6041	>	break;
6042	>	}
6043	>	}
6044	>	}
6045	>	}
6046	>	}
6047	>
6048	>	@SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
6049	>	extends Traverser<K,V,K> {
6050	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
6051	>	K result;
6052	>	ReduceKeysTask<K,V> rights, nextRight;
6053	>	ReduceKeysTask
6054	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6055	>	ReduceKeysTask<K,V> nextRight,
6056	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
6057	>	super(m, p, b); this.nextRight = nextRight;
6058	>	this.reducer = reducer;
6059	>	}
6060	>	public final K getRawResult() { return result; }
6061	>	@SuppressWarnings("unchecked") public final void compute() {
6062	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
6063	>	if ((reducer = this.reducer) != null) {
6064	>	for (int b; (b = preSplit()) > 0;)
6065	>	(rights = new ReduceKeysTask<K,V>
6066	>	(map, this, b, rights, reducer)).fork();
6067	>	K u, r = null;
6068	>	while ((u = advanceKey()) != null) {
6069	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
6070	>	}
6071	>	result = r;
6072	>	CountedCompleter<?> c;
6073	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6074	>	ReduceKeysTask<K,V>
6075	>	t = (ReduceKeysTask<K,V>)c,
6076	>	s = t.rights;
6077	>	while (s != null) {
6078	>	K tr, sr;
6079	>	if ((sr = s.result) != null)
6080	>	t.result = (((tr = t.result) == null) ? sr :
6081	>	reducer.apply(tr, sr));
6082	>	s = t.rights = s.nextRight;
6083	>	}
6084	>	}
6085	>	}
6086	>	}
6087	>	}
6088	>
6089	>	@SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
6090	>	extends Traverser<K,V,V> {
6091	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
6092	>	V result;
6093	>	ReduceValuesTask<K,V> rights, nextRight;
6094	>	ReduceValuesTask
6095	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6096	>	ReduceValuesTask<K,V> nextRight,
6097	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
6098	>	super(m, p, b); this.nextRight = nextRight;
6099	>	this.reducer = reducer;
6100	>	}
6101	>	public final V getRawResult() { return result; }
6102	>	@SuppressWarnings("unchecked") public final void compute() {
6103	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
6104	>	if ((reducer = this.reducer) != null) {
6105	>	for (int b; (b = preSplit()) > 0;)
6106	>	(rights = new ReduceValuesTask<K,V>
6107	>	(map, this, b, rights, reducer)).fork();
6108	>	V r = null, v;
6109	>	while ((v = advanceValue()) != null)
6110	>	r = (r == null) ? v : reducer.apply(r, v);
6111	>	result = r;
6112	>	CountedCompleter<?> c;
6113	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6114	>	ReduceValuesTask<K,V>
6115	>	t = (ReduceValuesTask<K,V>)c,
6116	>	s = t.rights;
6117	>	while (s != null) {
6118	>	V tr, sr;
6119	>	if ((sr = s.result) != null)
6120	>	t.result = (((tr = t.result) == null) ? sr :
6121	>	reducer.apply(tr, sr));
6122	>	s = t.rights = s.nextRight;
6123	>	}
6124	>	}
6125	>	}
6126	>	}
6127	>	}
6128	>
6129	>	@SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
6130	>	extends Traverser<K,V,Map.Entry<K,V>> {
6131	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
6132	>	Map.Entry<K,V> result;
6133	>	ReduceEntriesTask<K,V> rights, nextRight;
6134	>	ReduceEntriesTask
6135	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6136	>	ReduceEntriesTask<K,V> nextRight,
6137	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
6138	>	super(m, p, b); this.nextRight = nextRight;
6139	>	this.reducer = reducer;
6140	>	}
6141	>	public final Map.Entry<K,V> getRawResult() { return result; }
6142	>	@SuppressWarnings("unchecked") public final void compute() {
6143	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
6144	>	if ((reducer = this.reducer) != null) {
6145	>	for (int b; (b = preSplit()) > 0;)
6146	>	(rights = new ReduceEntriesTask<K,V>
6147	>	(map, this, b, rights, reducer)).fork();
6148	>	Map.Entry<K,V> r = null;
6149	>	V v;
6150	>	while ((v = advanceValue()) != null) {
6151	>	Map.Entry<K,V> u = entryFor(nextKey, v);
6152	>	r = (r == null) ? u : reducer.apply(r, u);
6153	>	}
6154	>	result = r;
6155	>	CountedCompleter<?> c;
6156	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6157	>	ReduceEntriesTask<K,V>
6158	>	t = (ReduceEntriesTask<K,V>)c,
6159	>	s = t.rights;
6160	>	while (s != null) {
6161	>	Map.Entry<K,V> tr, sr;
6162	>	if ((sr = s.result) != null)
6163	>	t.result = (((tr = t.result) == null) ? sr :
6164	>	reducer.apply(tr, sr));
6165	>	s = t.rights = s.nextRight;
6166	>	}
6167	>	}
6168	>	}
6169	>	}
6170	>	}
6171	>
6172	>	@SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
6173	>	extends Traverser<K,V,U> {
6174	>	final Function<? super K, ? extends U> transformer;
6175	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6176	>	U result;
6177	>	MapReduceKeysTask<K,V,U> rights, nextRight;
6178	>	MapReduceKeysTask
6179	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6180	>	MapReduceKeysTask<K,V,U> nextRight,
6181	>	Function<? super K, ? extends U> transformer,
6182	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6183	>	super(m, p, b); this.nextRight = nextRight;
6184	>	this.transformer = transformer;
6185	>	this.reducer = reducer;
6186	>	}
6187	>	public final U getRawResult() { return result; }
6188	>	@SuppressWarnings("unchecked") public final void compute() {
6189	>	final Function<? super K, ? extends U> transformer;
6190	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6191	>	if ((transformer = this.transformer) != null &&
6192	>	(reducer = this.reducer) != null) {
6193	>	for (int b; (b = preSplit()) > 0;)
6194	>	(rights = new MapReduceKeysTask<K,V,U>
6195	>	(map, this, b, rights, transformer, reducer)).fork();
6196	>	K k; U r = null, u;
6197	>	while ((k = advanceKey()) != null) {
6198	>	if ((u = transformer.apply(k)) != null)
6199	>	r = (r == null) ? u : reducer.apply(r, u);
6200	>	}
6201	>	result = r;
6202	>	CountedCompleter<?> c;
6203	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6204	>	MapReduceKeysTask<K,V,U>
6205	>	t = (MapReduceKeysTask<K,V,U>)c,
6206	>	s = t.rights;
6207	>	while (s != null) {
6208	>	U tr, sr;
6209	>	if ((sr = s.result) != null)
6210	>	t.result = (((tr = t.result) == null) ? sr :
6211	>	reducer.apply(tr, sr));
6212	>	s = t.rights = s.nextRight;
6213	>	}
6214	>	}
6215	>	}
6216	>	}
6217	>	}
6218	>
6219	>	@SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
6220	>	extends Traverser<K,V,U> {
6221	>	final Function<? super V, ? extends U> transformer;
6222	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6223	>	U result;
6224	>	MapReduceValuesTask<K,V,U> rights, nextRight;
6225	>	MapReduceValuesTask
6226	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6227	>	MapReduceValuesTask<K,V,U> nextRight,
6228	>	Function<? super V, ? extends U> transformer,
6229	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6230	>	super(m, p, b); this.nextRight = nextRight;
6231	>	this.transformer = transformer;
6232	>	this.reducer = reducer;
6233	>	}
6234	>	public final U getRawResult() { return result; }
6235	>	@SuppressWarnings("unchecked") public final void compute() {
6236	>	final Function<? super V, ? extends U> transformer;
6237	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6238	>	if ((transformer = this.transformer) != null &&
6239	>	(reducer = this.reducer) != null) {
6240	>	for (int b; (b = preSplit()) > 0;)
6241	>	(rights = new MapReduceValuesTask<K,V,U>
6242	>	(map, this, b, rights, transformer, reducer)).fork();
6243	>	U r = null, u;
6244	>	V v;
6245	>	while ((v = advanceValue()) != null) {
6246	>	if ((u = transformer.apply(v)) != null)
6247	>	r = (r == null) ? u : reducer.apply(r, u);
6248	>	}
6249	>	result = r;
6250	>	CountedCompleter<?> c;
6251	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6252	>	MapReduceValuesTask<K,V,U>
6253	>	t = (MapReduceValuesTask<K,V,U>)c,
6254	>	s = t.rights;
6255	>	while (s != null) {
6256	>	U tr, sr;
6257	>	if ((sr = s.result) != null)
6258	>	t.result = (((tr = t.result) == null) ? sr :
6259	>	reducer.apply(tr, sr));
6260	>	s = t.rights = s.nextRight;
6261	>	}
6262	>	}
6263	>	}
6264	>	}
6265	>	}
6266	>
6267	>	@SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
6268	>	extends Traverser<K,V,U> {
6269	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
6270	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6271	>	U result;
6272	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
6273	>	MapReduceEntriesTask
6274	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6275	>	MapReduceEntriesTask<K,V,U> nextRight,
6276	>	Function<Map.Entry<K,V>, ? extends U> transformer,
6277	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6278	>	super(m, p, b); this.nextRight = nextRight;
6279	>	this.transformer = transformer;
6280	>	this.reducer = reducer;
6281	>	}
6282	>	public final U getRawResult() { return result; }
6283	>	@SuppressWarnings("unchecked") public final void compute() {
6284	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
6285	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6286	>	if ((transformer = this.transformer) != null &&
6287	>	(reducer = this.reducer) != null) {
6288	>	for (int b; (b = preSplit()) > 0;)
6289	>	(rights = new MapReduceEntriesTask<K,V,U>
6290	>	(map, this, b, rights, transformer, reducer)).fork();
6291	>	U r = null, u;
6292	>	V v;
6293	>	while ((v = advanceValue()) != null) {
6294	>	if ((u = transformer.apply(entryFor(nextKey,
6295	>	v))) != null)
6296	>	r = (r == null) ? u : reducer.apply(r, u);
6297	>	}
6298	>	result = r;
6299	>	CountedCompleter<?> c;
6300	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6301	>	MapReduceEntriesTask<K,V,U>
6302	>	t = (MapReduceEntriesTask<K,V,U>)c,
6303	>	s = t.rights;
6304	>	while (s != null) {
6305	>	U tr, sr;
6306	>	if ((sr = s.result) != null)
6307	>	t.result = (((tr = t.result) == null) ? sr :
6308	>	reducer.apply(tr, sr));
6309	>	s = t.rights = s.nextRight;
6310	>	}
6311	>	}
6312	>	}
6313	>	}
6314	>	}
6315	>
6316	>	@SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
6317	>	extends Traverser<K,V,U> {
6318	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
6319	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6320	>	U result;
6321	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
6322	>	MapReduceMappingsTask
6323	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6324	>	MapReduceMappingsTask<K,V,U> nextRight,
6325	>	BiFunction<? super K, ? super V, ? extends U> transformer,
6326	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6327	>	super(m, p, b); this.nextRight = nextRight;
6328	>	this.transformer = transformer;
6329	>	this.reducer = reducer;
6330	>	}
6331	>	public final U getRawResult() { return result; }
6332	>	@SuppressWarnings("unchecked") public final void compute() {
6333	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
6334	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6335	>	if ((transformer = this.transformer) != null &&
6336	>	(reducer = this.reducer) != null) {
6337	>	for (int b; (b = preSplit()) > 0;)
6338	>	(rights = new MapReduceMappingsTask<K,V,U>
6339	>	(map, this, b, rights, transformer, reducer)).fork();
6340	>	U r = null, u;
6341	>	V v;
6342	>	while ((v = advanceValue()) != null) {
6343	>	if ((u = transformer.apply(nextKey, v)) != null)
6344	>	r = (r == null) ? u : reducer.apply(r, u);
6345	>	}
6346	>	result = r;
6347	>	CountedCompleter<?> c;
6348	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6349	>	MapReduceMappingsTask<K,V,U>
6350	>	t = (MapReduceMappingsTask<K,V,U>)c,
6351	>	s = t.rights;
6352	>	while (s != null) {
6353	>	U tr, sr;
6354	>	if ((sr = s.result) != null)
6355	>	t.result = (((tr = t.result) == null) ? sr :
6356	>	reducer.apply(tr, sr));
6357	>	s = t.rights = s.nextRight;
6358	>	}
6359	>	}
6360	>	}
6361	>	}
6362	>	}
6363	>
6364	>	@SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
6365	>	extends Traverser<K,V,Double> {
6366	>	final ToDoubleFunction<? super K> transformer;
6367	>	final DoubleBinaryOperator reducer;
6368	>	final double basis;
6369	>	double result;
6370	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
6371	>	MapReduceKeysToDoubleTask
6372	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6373	>	MapReduceKeysToDoubleTask<K,V> nextRight,
6374	>	ToDoubleFunction<? super K> transformer,
6375	>	double basis,
6376	>	DoubleBinaryOperator reducer) {
6377	>	super(m, p, b); this.nextRight = nextRight;
6378	>	this.transformer = transformer;
6379	>	this.basis = basis; this.reducer = reducer;
6380	>	}
6381	>	public final Double getRawResult() { return result; }
6382	>	@SuppressWarnings("unchecked") public final void compute() {
6383	>	final ToDoubleFunction<? super K> transformer;
6384	>	final DoubleBinaryOperator reducer;
6385	>	if ((transformer = this.transformer) != null &&
6386	>	(reducer = this.reducer) != null) {
6387	>	double r = this.basis;
6388	>	for (int b; (b = preSplit()) > 0;)
6389	>	(rights = new MapReduceKeysToDoubleTask<K,V>
6390	>	(map, this, b, rights, transformer, r, reducer)).fork();
6391	>	K k;
6392	>	while ((k = advanceKey()) != null)
6393	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(k));
6394	>	result = r;
6395	>	CountedCompleter<?> c;
6396	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6397	>	MapReduceKeysToDoubleTask<K,V>
6398	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
6399	>	s = t.rights;
6400	>	while (s != null) {
6401	>	t.result = reducer.applyAsDouble(t.result, s.result);
6402	>	s = t.rights = s.nextRight;
6403	>	}
6404	>	}
6405	>	}
6406	>	}
6407	>	}
6408	>
6409	>	@SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
6410	>	extends Traverser<K,V,Double> {
6411	>	final ToDoubleFunction<? super V> transformer;
6412	>	final DoubleBinaryOperator reducer;
6413	>	final double basis;
6414	>	double result;
6415	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
6416	>	MapReduceValuesToDoubleTask
6417	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6418	>	MapReduceValuesToDoubleTask<K,V> nextRight,
6419	>	ToDoubleFunction<? super V> transformer,
6420	>	double basis,
6421	>	DoubleBinaryOperator reducer) {
6422	>	super(m, p, b); this.nextRight = nextRight;
6423	>	this.transformer = transformer;
6424	>	this.basis = basis; this.reducer = reducer;
6425	>	}
6426	>	public final Double getRawResult() { return result; }
6427	>	@SuppressWarnings("unchecked") public final void compute() {
6428	>	final ToDoubleFunction<? super V> transformer;
6429	>	final DoubleBinaryOperator reducer;
6430	>	if ((transformer = this.transformer) != null &&
6431	>	(reducer = this.reducer) != null) {
6432	>	double r = this.basis;
6433	>	for (int b; (b = preSplit()) > 0;)
6434	>	(rights = new MapReduceValuesToDoubleTask<K,V>
6435	>	(map, this, b, rights, transformer, r, reducer)).fork();
6436	>	V v;
6437	>	while ((v = advanceValue()) != null)
6438	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
6439	>	result = r;
6440	>	CountedCompleter<?> c;
6441	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6442	>	MapReduceValuesToDoubleTask<K,V>
6443	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
6444	>	s = t.rights;
6445	>	while (s != null) {
6446	>	t.result = reducer.applyAsDouble(t.result, s.result);
6447	>	s = t.rights = s.nextRight;
6448	>	}
6449	>	}
6450	>	}
6451	>	}
6452	>	}
6453	>
6454	>	@SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6455	>	extends Traverser<K,V,Double> {
6456	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
6457	>	final DoubleBinaryOperator reducer;
6458	>	final double basis;
6459	>	double result;
6460	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6461	>	MapReduceEntriesToDoubleTask
6462	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6463	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
6464	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
6465	>	double basis,
6466	>	DoubleBinaryOperator reducer) {
6467	>	super(m, p, b); this.nextRight = nextRight;
6468	>	this.transformer = transformer;
6469	>	this.basis = basis; this.reducer = reducer;
6470	>	}
6471	>	public final Double getRawResult() { return result; }
6472	>	@SuppressWarnings("unchecked") public final void compute() {
6473	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
6474	>	final DoubleBinaryOperator reducer;
6475	>	if ((transformer = this.transformer) != null &&
6476	>	(reducer = this.reducer) != null) {
6477	>	double r = this.basis;
6478	>	for (int b; (b = preSplit()) > 0;)
6479	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
6480	>	(map, this, b, rights, transformer, r, reducer)).fork();
6481	>	V v;
6482	>	while ((v = advanceValue()) != null)
6483	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor(nextKey,
6484	>	v)));
6485	>	result = r;
6486	>	CountedCompleter<?> c;
6487	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6488	>	MapReduceEntriesToDoubleTask<K,V>
6489	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
6490	>	s = t.rights;
6491	>	while (s != null) {
6492	>	t.result = reducer.applyAsDouble(t.result, s.result);
6493	>	s = t.rights = s.nextRight;
6494	>	}
6495	>	}
6496	>	}
6497	>	}
6498	>	}
6499	>
6500	>	@SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6501	>	extends Traverser<K,V,Double> {
6502	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
6503	>	final DoubleBinaryOperator reducer;
6504	>	final double basis;
6505	>	double result;
6506	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6507	>	MapReduceMappingsToDoubleTask
6508	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6509	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
6510	>	ToDoubleBiFunction<? super K, ? super V> transformer,
6511	>	double basis,
6512	>	DoubleBinaryOperator reducer) {
6513	>	super(m, p, b); this.nextRight = nextRight;
6514	>	this.transformer = transformer;
6515	>	this.basis = basis; this.reducer = reducer;
6516	>	}
6517	>	public final Double getRawResult() { return result; }
6518	>	@SuppressWarnings("unchecked") public final void compute() {
6519	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
6520	>	final DoubleBinaryOperator reducer;
6521	>	if ((transformer = this.transformer) != null &&
6522	>	(reducer = this.reducer) != null) {
6523	>	double r = this.basis;
6524	>	for (int b; (b = preSplit()) > 0;)
6525	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
6526	>	(map, this, b, rights, transformer, r, reducer)).fork();
6527	>	V v;
6528	>	while ((v = advanceValue()) != null)
6529	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(nextKey, v));
6530	>	result = r;
6531	>	CountedCompleter<?> c;
6532	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6533	>	MapReduceMappingsToDoubleTask<K,V>
6534	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
6535	>	s = t.rights;
6536	>	while (s != null) {
6537	>	t.result = reducer.applyAsDouble(t.result, s.result);
6538	>	s = t.rights = s.nextRight;
6539	>	}
6540	>	}
6541	>	}
6542	>	}
6543	>	}
6544	>
6545	>	@SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6546	>	extends Traverser<K,V,Long> {
6547	>	final ToLongFunction<? super K> transformer;
6548	>	final LongBinaryOperator reducer;
6549	>	final long basis;
6550	>	long result;
6551	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
6552	>	MapReduceKeysToLongTask
6553	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6554	>	MapReduceKeysToLongTask<K,V> nextRight,
6555	>	ToLongFunction<? super K> transformer,
6556	>	long basis,
6557	>	LongBinaryOperator reducer) {
6558	>	super(m, p, b); this.nextRight = nextRight;
6559	>	this.transformer = transformer;
6560	>	this.basis = basis; this.reducer = reducer;
6561	>	}
6562	>	public final Long getRawResult() { return result; }
6563	>	@SuppressWarnings("unchecked") public final void compute() {
6564	>	final ToLongFunction<? super K> transformer;
6565	>	final LongBinaryOperator reducer;
6566	>	if ((transformer = this.transformer) != null &&
6567	>	(reducer = this.reducer) != null) {
6568	>	long r = this.basis;
6569	>	for (int b; (b = preSplit()) > 0;)
6570	>	(rights = new MapReduceKeysToLongTask<K,V>
6571	>	(map, this, b, rights, transformer, r, reducer)).fork();
6572	>	K k;
6573	>	while ((k = advanceKey()) != null)
6574	>	r = reducer.applyAsLong(r, transformer.applyAsLong(k));
6575	>	result = r;
6576	>	CountedCompleter<?> c;
6577	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6578	>	MapReduceKeysToLongTask<K,V>
6579	>	t = (MapReduceKeysToLongTask<K,V>)c,
6580	>	s = t.rights;
6581	>	while (s != null) {
6582	>	t.result = reducer.applyAsLong(t.result, s.result);
6583	>	s = t.rights = s.nextRight;
6584	>	}
6585	>	}
6586	>	}
6587	>	}
6588	>	}
6589	>
6590	>	@SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6591	>	extends Traverser<K,V,Long> {
6592	>	final ToLongFunction<? super V> transformer;
6593	>	final LongBinaryOperator reducer;
6594	>	final long basis;
6595	>	long result;
6596	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
6597	>	MapReduceValuesToLongTask
6598	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6599	>	MapReduceValuesToLongTask<K,V> nextRight,
6600	>	ToLongFunction<? super V> transformer,
6601	>	long basis,
6602	>	LongBinaryOperator reducer) {
6603	>	super(m, p, b); this.nextRight = nextRight;
6604	>	this.transformer = transformer;
6605	>	this.basis = basis; this.reducer = reducer;
6606	>	}
6607	>	public final Long getRawResult() { return result; }
6608	>	@SuppressWarnings("unchecked") public final void compute() {
6609	>	final ToLongFunction<? super V> transformer;
6610	>	final LongBinaryOperator reducer;
6611	>	if ((transformer = this.transformer) != null &&
6612	>	(reducer = this.reducer) != null) {
6613	>	long r = this.basis;
6614	>	for (int b; (b = preSplit()) > 0;)
6615	>	(rights = new MapReduceValuesToLongTask<K,V>
6616	>	(map, this, b, rights, transformer, r, reducer)).fork();
6617	>	V v;
6618	>	while ((v = advanceValue()) != null)
6619	>	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
6620	>	result = r;
6621	>	CountedCompleter<?> c;
6622	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6623	>	MapReduceValuesToLongTask<K,V>
6624	>	t = (MapReduceValuesToLongTask<K,V>)c,
6625	>	s = t.rights;
6626	>	while (s != null) {
6627	>	t.result = reducer.applyAsLong(t.result, s.result);
6628	>	s = t.rights = s.nextRight;
6629	>	}
6630	>	}
6631	>	}
6632	>	}
6633	>	}
6634	>
6635	>	@SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6636	>	extends Traverser<K,V,Long> {
6637	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6638	>	final LongBinaryOperator reducer;
6639	>	final long basis;
6640	>	long result;
6641	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6642	>	MapReduceEntriesToLongTask
6643	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6644	>	MapReduceEntriesToLongTask<K,V> nextRight,
6645	>	ToLongFunction<Map.Entry<K,V>> transformer,
6646	>	long basis,
6647	>	LongBinaryOperator reducer) {
6648	>	super(m, p, b); this.nextRight = nextRight;
6649	>	this.transformer = transformer;
6650	>	this.basis = basis; this.reducer = reducer;
6651	>	}
6652	>	public final Long getRawResult() { return result; }
6653	>	@SuppressWarnings("unchecked") public final void compute() {
6654	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6655	>	final LongBinaryOperator reducer;
6656	>	if ((transformer = this.transformer) != null &&
6657	>	(reducer = this.reducer) != null) {
6658	>	long r = this.basis;
6659	>	for (int b; (b = preSplit()) > 0;)
6660	>	(rights = new MapReduceEntriesToLongTask<K,V>
6661	>	(map, this, b, rights, transformer, r, reducer)).fork();
6662	>	V v;
6663	>	while ((v = advanceValue()) != null)
6664	>	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor(nextKey, v)));
6665	>	result = r;
6666	>	CountedCompleter<?> c;
6667	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6668	>	MapReduceEntriesToLongTask<K,V>
6669	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6670	>	s = t.rights;
6671	>	while (s != null) {
6672	>	t.result = reducer.applyAsLong(t.result, s.result);
6673	>	s = t.rights = s.nextRight;
6674	>	}
6675	>	}
6676	>	}
6677	>	}
6678	>	}
6679	>
6680	>	@SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6681	>	extends Traverser<K,V,Long> {
6682	>	final ToLongBiFunction<? super K, ? super V> transformer;
6683	>	final LongBinaryOperator reducer;
6684	>	final long basis;
6685	>	long result;
6686	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6687	>	MapReduceMappingsToLongTask
6688	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6689	>	MapReduceMappingsToLongTask<K,V> nextRight,
6690	>	ToLongBiFunction<? super K, ? super V> transformer,
6691	>	long basis,
6692	>	LongBinaryOperator reducer) {
6693	>	super(m, p, b); this.nextRight = nextRight;
6694	>	this.transformer = transformer;
6695	>	this.basis = basis; this.reducer = reducer;
6696	>	}
6697	>	public final Long getRawResult() { return result; }
6698	>	@SuppressWarnings("unchecked") public final void compute() {
6699	>	final ToLongBiFunction<? super K, ? super V> transformer;
6700	>	final LongBinaryOperator reducer;
6701	>	if ((transformer = this.transformer) != null &&
6702	>	(reducer = this.reducer) != null) {
6703	>	long r = this.basis;
6704	>	for (int b; (b = preSplit()) > 0;)
6705	>	(rights = new MapReduceMappingsToLongTask<K,V>
6706	>	(map, this, b, rights, transformer, r, reducer)).fork();
6707	>	V v;
6708	>	while ((v = advanceValue()) != null)
6709	>	r = reducer.applyAsLong(r, transformer.applyAsLong(nextKey, v));
6710	>	result = r;
6711	>	CountedCompleter<?> c;
6712	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6713	>	MapReduceMappingsToLongTask<K,V>
6714	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6715	>	s = t.rights;
6716	>	while (s != null) {
6717	>	t.result = reducer.applyAsLong(t.result, s.result);
6718	>	s = t.rights = s.nextRight;
6719	>	}
6720	>	}
6721	>	}
6722	>	}
6723	>	}
6724	>
6725	>	@SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6726	>	extends Traverser<K,V,Integer> {
6727	>	final ToIntFunction<? super K> transformer;
6728	>	final IntBinaryOperator reducer;
6729	>	final int basis;
6730	>	int result;
6731	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6732	>	MapReduceKeysToIntTask
6733	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6734	>	MapReduceKeysToIntTask<K,V> nextRight,
6735	>	ToIntFunction<? super K> transformer,
6736	>	int basis,
6737	>	IntBinaryOperator reducer) {
6738	>	super(m, p, b); this.nextRight = nextRight;
6739	>	this.transformer = transformer;
6740	>	this.basis = basis; this.reducer = reducer;
6741	>	}
6742	>	public final Integer getRawResult() { return result; }
6743	>	@SuppressWarnings("unchecked") public final void compute() {
6744	>	final ToIntFunction<? super K> transformer;
6745	>	final IntBinaryOperator reducer;
6746	>	if ((transformer = this.transformer) != null &&
6747	>	(reducer = this.reducer) != null) {
6748	>	int r = this.basis;
6749	>	for (int b; (b = preSplit()) > 0;)
6750	>	(rights = new MapReduceKeysToIntTask<K,V>
6751	>	(map, this, b, rights, transformer, r, reducer)).fork();
6752	>	K k;
6753	>	while ((k = advanceKey()) != null)
6754	>	r = reducer.applyAsInt(r, transformer.applyAsInt(k));
6755	>	result = r;
6756	>	CountedCompleter<?> c;
6757	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6758	>	MapReduceKeysToIntTask<K,V>
6759	>	t = (MapReduceKeysToIntTask<K,V>)c,
6760	>	s = t.rights;
6761	>	while (s != null) {
6762	>	t.result = reducer.applyAsInt(t.result, s.result);
6763	>	s = t.rights = s.nextRight;
6764	>	}
6765	>	}
6766	>	}
6767	>	}
6768	>	}
6769	>
6770	>	@SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6771	>	extends Traverser<K,V,Integer> {
6772	>	final ToIntFunction<? super V> transformer;
6773	>	final IntBinaryOperator reducer;
6774	>	final int basis;
6775	>	int result;
6776	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6777	>	MapReduceValuesToIntTask
6778	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6779	>	MapReduceValuesToIntTask<K,V> nextRight,
6780	>	ToIntFunction<? super V> transformer,
6781	>	int basis,
6782	>	IntBinaryOperator reducer) {
6783	>	super(m, p, b); this.nextRight = nextRight;
6784	>	this.transformer = transformer;
6785	>	this.basis = basis; this.reducer = reducer;
6786	>	}
6787	>	public final Integer getRawResult() { return result; }
6788	>	@SuppressWarnings("unchecked") public final void compute() {
6789	>	final ToIntFunction<? super V> transformer;
6790	>	final IntBinaryOperator reducer;
6791	>	if ((transformer = this.transformer) != null &&
6792	>	(reducer = this.reducer) != null) {
6793	>	int r = this.basis;
6794	>	for (int b; (b = preSplit()) > 0;)
6795	>	(rights = new MapReduceValuesToIntTask<K,V>
6796	>	(map, this, b, rights, transformer, r, reducer)).fork();
6797	>	V v;
6798	>	while ((v = advanceValue()) != null)
6799	>	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
6800	>	result = r;
6801	>	CountedCompleter<?> c;
6802	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6803	>	MapReduceValuesToIntTask<K,V>
6804	>	t = (MapReduceValuesToIntTask<K,V>)c,
6805	>	s = t.rights;
6806	>	while (s != null) {
6807	>	t.result = reducer.applyAsInt(t.result, s.result);
6808	>	s = t.rights = s.nextRight;
6809	>	}
6810	>	}
6811	>	}
6812	>	}
6813	>	}
6814	>
6815	>	@SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6816	>	extends Traverser<K,V,Integer> {
6817	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6818	>	final IntBinaryOperator reducer;
6819	>	final int basis;
6820	>	int result;
6821	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6822	>	MapReduceEntriesToIntTask
6823	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6824	>	MapReduceEntriesToIntTask<K,V> nextRight,
6825	>	ToIntFunction<Map.Entry<K,V>> transformer,
6826	>	int basis,
6827	>	IntBinaryOperator reducer) {
6828	>	super(m, p, b); this.nextRight = nextRight;
6829	>	this.transformer = transformer;
6830	>	this.basis = basis; this.reducer = reducer;
6831	>	}
6832	>	public final Integer getRawResult() { return result; }
6833	>	@SuppressWarnings("unchecked") public final void compute() {
6834	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6835	>	final IntBinaryOperator reducer;
6836	>	if ((transformer = this.transformer) != null &&
6837	>	(reducer = this.reducer) != null) {
6838	>	int r = this.basis;
6839	>	for (int b; (b = preSplit()) > 0;)
6840	>	(rights = new MapReduceEntriesToIntTask<K,V>
6841	>	(map, this, b, rights, transformer, r, reducer)).fork();
6842	>	V v;
6843	>	while ((v = advanceValue()) != null)
6844	>	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor(nextKey,
6845	>	v)));
6846	>	result = r;
6847	>	CountedCompleter<?> c;
6848	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6849	>	MapReduceEntriesToIntTask<K,V>
6850	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6851	>	s = t.rights;
6852	>	while (s != null) {
6853	>	t.result = reducer.applyAsInt(t.result, s.result);
6854	>	s = t.rights = s.nextRight;
6855	>	}
6856	>	}
6857	>	}
6858	>	}
6859	>	}
6860	>
6861	>	@SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6862	>	extends Traverser<K,V,Integer> {
6863	>	final ToIntBiFunction<? super K, ? super V> transformer;
6864	>	final IntBinaryOperator reducer;
6865	>	final int basis;
6866	>	int result;
6867	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6868	>	MapReduceMappingsToIntTask
6869	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6870	>	MapReduceMappingsToIntTask<K,V> nextRight,
6871	>	ToIntBiFunction<? super K, ? super V> transformer,
6872	>	int basis,
6873	>	IntBinaryOperator reducer) {
6874	>	super(m, p, b); this.nextRight = nextRight;
6875	>	this.transformer = transformer;
6876	>	this.basis = basis; this.reducer = reducer;
6877	>	}
6878	>	public final Integer getRawResult() { return result; }
6879	>	@SuppressWarnings("unchecked") public final void compute() {
6880	>	final ToIntBiFunction<? super K, ? super V> transformer;
6881	>	final IntBinaryOperator reducer;
6882	>	if ((transformer = this.transformer) != null &&
6883	>	(reducer = this.reducer) != null) {
6884	>	int r = this.basis;
6885	>	for (int b; (b = preSplit()) > 0;)
6886	>	(rights = new MapReduceMappingsToIntTask<K,V>
6887	>	(map, this, b, rights, transformer, r, reducer)).fork();
6888	>	V v;
6889	>	while ((v = advanceValue()) != null)
6890	>	r = reducer.applyAsInt(r, transformer.applyAsInt(nextKey, v));
6891	>	result = r;
6892	>	CountedCompleter<?> c;
6893	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6894	>	MapReduceMappingsToIntTask<K,V>
6895	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6896	>	s = t.rights;
6897	>	while (s != null) {
6898	>	t.result = reducer.applyAsInt(t.result, s.result);
6899	>	s = t.rights = s.nextRight;
6900	>	}
6901	>	}
6902	>	}
6903		}
6904		}
6905
6906		// Unsafe mechanics
6907	<	private static final sun.misc.Unsafe UNSAFE;
6908	<	private static final long SBASE;
6909	<	private static final int SSHIFT;
6910	<	private static final long TBASE;
6911	<	private static final int TSHIFT;
6907	>	private static final sun.misc.Unsafe U;
6908	>	private static final long SIZECTL;
6909	>	private static final long TRANSFERINDEX;
6910	>	private static final long TRANSFERORIGIN;
6911	>	private static final long BASECOUNT;
6912	>	private static final long CELLSBUSY;
6913	>	private static final long CELLVALUE;
6914	>	private static final long ABASE;
6915	>	private static final int ASHIFT;
6916
6917		static {
1467	–	int ss, ts;
6918		try {
6919	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
6920	<	Class<?> tc = HashEntry[].class;
6921	<	Class<?> sc = Segment[].class;
6922	<	TBASE = UNSAFE.arrayBaseOffset(tc);
6923	<	SBASE = UNSAFE.arrayBaseOffset(sc);
6924	<	ts = UNSAFE.arrayIndexScale(tc);
6925	<	ss = UNSAFE.arrayIndexScale(sc);
6919	>	U = sun.misc.Unsafe.getUnsafe();
6920	>	Class<?> k = ConcurrentHashMap.class;
6921	>	SIZECTL = U.objectFieldOffset
6922	>	(k.getDeclaredField("sizeCtl"));
6923	>	TRANSFERINDEX = U.objectFieldOffset
6924	>	(k.getDeclaredField("transferIndex"));
6925	>	TRANSFERORIGIN = U.objectFieldOffset
6926	>	(k.getDeclaredField("transferOrigin"));
6927	>	BASECOUNT = U.objectFieldOffset
6928	>	(k.getDeclaredField("baseCount"));
6929	>	CELLSBUSY = U.objectFieldOffset
6930	>	(k.getDeclaredField("cellsBusy"));
6931	>	Class<?> ck = Cell.class;
6932	>	CELLVALUE = U.objectFieldOffset
6933	>	(ck.getDeclaredField("value"));
6934	>	Class<?> sc = Node[].class;
6935	>	ABASE = U.arrayBaseOffset(sc);
6936	>	int scale = U.arrayIndexScale(sc);
6937	>	if ((scale & (scale - 1)) != 0)
6938	>	throw new Error("data type scale not a power of two");
6939	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6940		} catch (Exception e) {
6941		throw new Error(e);
6942		}
1479	–	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
1480	–	throw new Error("data type scale not a power of two");
1481	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1482	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
6943		}
6944
6945		}

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