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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.99 by dl, Tue Apr 12 22:52:07 2011 UTC vs.
Revision 1.299 by jsr166, Sat Mar 18 19:19:04 2017 UTC

#	Line 1 | Line 1
1		/*
2		* Written by Doug Lea with assistance from members of JCP JSR-166
3		* Expert Group and released to the public domain, as explained at
4	<	* http://creativecommhons.org/publicdomain/zero/1.0/
4	>	* http://creativecommons.org/publicdomain/zero/1.0/
5		*/
6
7		package java.util.concurrent;
8	<	import java.util.concurrent.locks.*;
9	<	import java.util.*;
8	>
9	>	import java.io.ObjectStreamField;
10		import java.io.Serializable;
11	<	import java.io.IOException;
12	<	import java.io.ObjectInputStream;
13	<	import java.io.ObjectOutputStream;
11	>	import java.lang.reflect.ParameterizedType;
12	>	import java.lang.reflect.Type;
13	>	import java.util.AbstractMap;
14	>	import java.util.Arrays;
15	>	import java.util.Collection;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.atomic.AtomicReference;
25	>	import java.util.concurrent.locks.LockSupport;
26	>	import java.util.concurrent.locks.ReentrantLock;
27	>	import java.util.function.BiConsumer;
28	>	import java.util.function.BiFunction;
29	>	import java.util.function.Consumer;
30	>	import java.util.function.DoubleBinaryOperator;
31	>	import java.util.function.Function;
32	>	import java.util.function.IntBinaryOperator;
33	>	import java.util.function.LongBinaryOperator;
34	>	import java.util.function.Predicate;
35	>	import java.util.function.ToDoubleBiFunction;
36	>	import java.util.function.ToDoubleFunction;
37	>	import java.util.function.ToIntBiFunction;
38	>	import java.util.function.ToIntFunction;
39	>	import java.util.function.ToLongBiFunction;
40	>	import java.util.function.ToLongFunction;
41	>	import java.util.stream.Stream;
42	>	import jdk.internal.misc.Unsafe;
43
44		/**
45		* A hash table supporting full concurrency of retrievals and
46	<	* adjustable expected concurrency for updates. This class obeys the
46	>	* high expected concurrency for updates. This class obeys the
47		* same functional specification as {@link java.util.Hashtable}, and
48		* includes versions of methods corresponding to each method of
49	<	* <tt>Hashtable</tt>. However, even though all operations are
49	>	* {@code Hashtable}. However, even though all operations are
50		* thread-safe, retrieval operations do <em>not</em> entail locking,
51		* and there is <em>not</em> any support for locking the entire table
52		* in a way that prevents all access.  This class is fully
53	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
53	>	* interoperable with {@code Hashtable} in programs that rely on its
54		* thread safety but not on its synchronization details.
55		*
56	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
57	<	* block, so may overlap with update operations (including
58	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
59	<	* of the most recently <em>completed</em> update operations holding
60	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
61	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
62	<	* removal of only some entries.  Similarly, Iterators and
63	<	* Enumerations return elements reflecting the state of the hash table
64	<	* at some point at or since the creation of the iterator/enumeration.
65	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
56	>	* <p>Retrieval operations (including {@code get}) generally do not
57	>	* block, so may overlap with update operations (including {@code put}
58	>	* and {@code remove}). Retrievals reflect the results of the most
59	>	* recently <em>completed</em> update operations holding upon their
60	>	* onset. (More formally, an update operation for a given key bears a
61	>	* <em>happens-before</em> relation with any (non-null) retrieval for
62	>	* that key reporting the updated value.)  For aggregate operations
63	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
64	>	* reflect insertion or removal of only some entries.  Similarly,
65	>	* Iterators, Spliterators and Enumerations return elements reflecting the
66	>	* state of the hash table at some point at or since the creation of the
67	>	* iterator/enumeration.  They do <em>not</em> throw {@link
68	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
69		* However, iterators are designed to be used by only one thread at a time.
70	+	* Bear in mind that the results of aggregate status methods including
71	+	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
72	+	* useful only when a map is not undergoing concurrent updates in other threads.
73	+	* Otherwise the results of these methods reflect transient states
74	+	* that may be adequate for monitoring or estimation purposes, but not
75	+	* for program control.
76	+	*
77	+	* <p>The table is dynamically expanded when there are too many
78	+	* collisions (i.e., keys that have distinct hash codes but fall into
79	+	* the same slot modulo the table size), with the expected average
80	+	* effect of maintaining roughly two bins per mapping (corresponding
81	+	* to a 0.75 load factor threshold for resizing). There may be much
82	+	* variance around this average as mappings are added and removed, but
83	+	* overall, this maintains a commonly accepted time/space tradeoff for
84	+	* hash tables.  However, resizing this or any other kind of hash
85	+	* table may be a relatively slow operation. When possible, it is a
86	+	* good idea to provide a size estimate as an optional {@code
87	+	* initialCapacity} constructor argument. An additional optional
88	+	* {@code loadFactor} constructor argument provides a further means of
89	+	* customizing initial table capacity by specifying the table density
90	+	* to be used in calculating the amount of space to allocate for the
91	+	* given number of elements.  Also, for compatibility with previous
92	+	* versions of this class, constructors may optionally specify an
93	+	* expected {@code concurrencyLevel} as an additional hint for
94	+	* internal sizing.  Note that using many keys with exactly the same
95	+	* {@code hashCode()} is a sure way to slow down performance of any
96	+	* hash table. To ameliorate impact, when keys are {@link Comparable},
97	+	* this class may use comparison order among keys to help break ties.
98	+	*
99	+	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
100	+	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
101	+	* (using {@link #keySet(Object)} when only keys are of interest, and the
102	+	* mapped values are (perhaps transiently) not used or all take the
103	+	* same mapping value.
104		*
105	<	* <p> The allowed concurrency among update operations is guided by
106	<	* the optional <tt>concurrencyLevel</tt> constructor argument
107	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
108	<	* table is internally partitioned to try to permit the indicated
109	<	* number of concurrent updates without contention. Because placement
110	<	* in hash tables is essentially random, the actual concurrency will
45	<	* vary.  Ideally, you should choose a value to accommodate as many
46	<	* threads as will ever concurrently modify the table. Using a
47	<	* significantly higher value than you need can waste space and time,
48	<	* and a significantly lower value can lead to thread contention. But
49	<	* overestimates and underestimates within an order of magnitude do
50	<	* not usually have much noticeable impact. A value of one is
51	<	* appropriate when it is known that only one thread will modify and
52	<	* all others will only read. Also, resizing this or any other kind of
53	<	* hash table is a relatively slow operation, so, when possible, it is
54	<	* a good idea to provide estimates of expected table sizes in
55	<	* constructors.
105	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
106	>	* form of histogram or multiset) by using {@link
107	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
108	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
109	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
110	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
111		*
112		* <p>This class and its views and iterators implement all of the
113		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
114		* interfaces.
115		*
116	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
117	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
116	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
117	>	* does <em>not</em> allow {@code null} to be used as a key or value.
118	>	*
119	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
120	>	* operations that, unlike most {@link Stream} methods, are designed
121	>	* to be safely, and often sensibly, applied even with maps that are
122	>	* being concurrently updated by other threads; for example, when
123	>	* computing a snapshot summary of the values in a shared registry.
124	>	* There are three kinds of operation, each with four forms, accepting
125	>	* functions with keys, values, entries, and (key, value) pairs as
126	>	* arguments and/or return values. Because the elements of a
127	>	* ConcurrentHashMap are not ordered in any particular way, and may be
128	>	* processed in different orders in different parallel executions, the
129	>	* correctness of supplied functions should not depend on any
130	>	* ordering, or on any other objects or values that may transiently
131	>	* change while computation is in progress; and except for forEach
132	>	* actions, should ideally be side-effect-free. Bulk operations on
133	>	* {@link java.util.Map.Entry} objects do not support method {@code
134	>	* setValue}.
135	>	*
136	>	* <ul>
137	>	* <li>forEach: Performs a given action on each element.
138	>	* A variant form applies a given transformation on each element
139	>	* before performing the action.
140	>	*
141	>	* <li>search: Returns the first available non-null result of
142	>	* applying a given function on each element; skipping further
143	>	* search when a result is found.
144	>	*
145	>	* <li>reduce: Accumulates each element.  The supplied reduction
146	>	* function cannot rely on ordering (more formally, it should be
147	>	* both associative and commutative).  There are five variants:
148	>	*
149	>	* <ul>
150	>	*
151	>	* <li>Plain reductions. (There is not a form of this method for
152	>	* (key, value) function arguments since there is no corresponding
153	>	* return type.)
154	>	*
155	>	* <li>Mapped reductions that accumulate the results of a given
156	>	* function applied to each element.
157	>	*
158	>	* <li>Reductions to scalar doubles, longs, and ints, using a
159	>	* given basis value.
160	>	*
161	>	* </ul>
162	>	* </ul>
163	>	*
164	>	* <p>These bulk operations accept a {@code parallelismThreshold}
165	>	* argument. Methods proceed sequentially if the current map size is
166	>	* estimated to be less than the given threshold. Using a value of
167	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
168	>	* of {@code 1} results in maximal parallelism by partitioning into
169	>	* enough subtasks to fully utilize the {@link
170	>	* ForkJoinPool#commonPool()} that is used for all parallel
171	>	* computations. Normally, you would initially choose one of these
172	>	* extreme values, and then measure performance of using in-between
173	>	* values that trade off overhead versus throughput.
174	>	*
175	>	* <p>The concurrency properties of bulk operations follow
176	>	* from those of ConcurrentHashMap: Any non-null result returned
177	>	* from {@code get(key)} and related access methods bears a
178	>	* happens-before relation with the associated insertion or
179	>	* update.  The result of any bulk operation reflects the
180	>	* composition of these per-element relations (but is not
181	>	* necessarily atomic with respect to the map as a whole unless it
182	>	* is somehow known to be quiescent).  Conversely, because keys
183	>	* and values in the map are never null, null serves as a reliable
184	>	* atomic indicator of the current lack of any result.  To
185	>	* maintain this property, null serves as an implicit basis for
186	>	* all non-scalar reduction operations. For the double, long, and
187	>	* int versions, the basis should be one that, when combined with
188	>	* any other value, returns that other value (more formally, it
189	>	* should be the identity element for the reduction). Most common
190	>	* reductions have these properties; for example, computing a sum
191	>	* with basis 0 or a minimum with basis MAX_VALUE.
192	>	*
193	>	* <p>Search and transformation functions provided as arguments
194	>	* should similarly return null to indicate the lack of any result
195	>	* (in which case it is not used). In the case of mapped
196	>	* reductions, this also enables transformations to serve as
197	>	* filters, returning null (or, in the case of primitive
198	>	* specializations, the identity basis) if the element should not
199	>	* be combined. You can create compound transformations and
200	>	* filterings by composing them yourself under this "null means
201	>	* there is nothing there now" rule before using them in search or
202	>	* reduce operations.
203	>	*
204	>	* <p>Methods accepting and/or returning Entry arguments maintain
205	>	* key-value associations. They may be useful for example when
206	>	* finding the key for the greatest value. Note that "plain" Entry
207	>	* arguments can be supplied using {@code new
208	>	* AbstractMap.SimpleEntry(k,v)}.
209	>	*
210	>	* <p>Bulk operations may complete abruptly, throwing an
211	>	* exception encountered in the application of a supplied
212	>	* function. Bear in mind when handling such exceptions that other
213	>	* concurrently executing functions could also have thrown
214	>	* exceptions, or would have done so if the first exception had
215	>	* not occurred.
216	>	*
217	>	* <p>Speedups for parallel compared to sequential forms are common
218	>	* but not guaranteed.  Parallel operations involving brief functions
219	>	* on small maps may execute more slowly than sequential forms if the
220	>	* underlying work to parallelize the computation is more expensive
221	>	* than the computation itself.  Similarly, parallelization may not
222	>	* lead to much actual parallelism if all processors are busy
223	>	* performing unrelated tasks.
224	>	*
225	>	* <p>All arguments to all task methods must be non-null.
226		*
227		* <p>This class is a member of the
228		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 70 | Line 233 | import java.io.ObjectOutputStream;
233		* @param <K> the type of keys maintained by this map
234		* @param <V> the type of mapped values
235		*/
236	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
237	<	implements ConcurrentMap<K, V>, Serializable {
236	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
237	>	implements ConcurrentMap<K,V>, Serializable {
238		private static final long serialVersionUID = 7249069246763182397L;
239
240		/*
241	<	* The basic strategy is to subdivide the table among Segments,
242	<	* each of which itself is a concurrently readable hash table.  To
243	<	* reduce footprint, all but one segments are constructed only
244	<	* when first needed (see ensureSegment). To maintain visibility
245	<	* in the presence of lazy construction, accesses to segments as
246	<	* well as elements of segment's table must use volatile access,
247	<	* which is done via Unsafe within methods segmentAt etc
248	<	* below. These provide the functionality of AtomicReferenceArrays
249	<	* but reduce the levels of indirection. Additionally,
250	<	* volatile-writes of table elements and entry "next" fields
251	<	* within locked operations use the cheaper "lazySet" forms of
252	<	* writes (via putOrderedObject) because these write are always
253	<	* followed by lock releases that maintain sequential consistency
254	<	* of table updates.
255	<	*
256	<	* Historical note: The previous version of this class relied
257	<	* heavily on "final" fields, which avoided some volatile reads at
258	<	* the expense of a large initial footprint.  Some remnants of
259	<	* that design (including forced construction of segment 0) exist
260	<	* to ensure serialization compatibility.
241	>	* Overview:
242	>	*
243	>	* The primary design goal of this hash table is to maintain
244	>	* concurrent readability (typically method get(), but also
245	>	* iterators and related methods) while minimizing update
246	>	* contention. Secondary goals are to keep space consumption about
247	>	* the same or better than java.util.HashMap, and to support high
248	>	* initial insertion rates on an empty table by many threads.
249	>	*
250	>	* This map usually acts as a binned (bucketed) hash table.  Each
251	>	* key-value mapping is held in a Node.  Most nodes are instances
252	>	* of the basic Node class with hash, key, value, and next
253	>	* fields. However, various subclasses exist: TreeNodes are
254	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
255	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
256	>	* of bins during resizing. ReservationNodes are used as
257	>	* placeholders while establishing values in computeIfAbsent and
258	>	* related methods.  The types TreeBin, ForwardingNode, and
259	>	* ReservationNode do not hold normal user keys, values, or
260	>	* hashes, and are readily distinguishable during search etc
261	>	* because they have negative hash fields and null key and value
262	>	* fields. (These special nodes are either uncommon or transient,
263	>	* so the impact of carrying around some unused fields is
264	>	* insignificant.)
265	>	*
266	>	* The table is lazily initialized to a power-of-two size upon the
267	>	* first insertion.  Each bin in the table normally contains a
268	>	* list of Nodes (most often, the list has only zero or one Node).
269	>	* Table accesses require volatile/atomic reads, writes, and
270	>	* CASes.  Because there is no other way to arrange this without
271	>	* adding further indirections, we use intrinsics
272	>	* (jdk.internal.misc.Unsafe) operations.
273	>	*
274	>	* We use the top (sign) bit of Node hash fields for control
275	>	* purposes -- it is available anyway because of addressing
276	>	* constraints.  Nodes with negative hash fields are specially
277	>	* handled or ignored in map methods.
278	>	*
279	>	* Insertion (via put or its variants) of the first node in an
280	>	* empty bin is performed by just CASing it to the bin.  This is
281	>	* by far the most common case for put operations under most
282	>	* key/hash distributions.  Other update operations (insert,
283	>	* delete, and replace) require locks.  We do not want to waste
284	>	* the space required to associate a distinct lock object with
285	>	* each bin, so instead use the first node of a bin list itself as
286	>	* a lock. Locking support for these locks relies on builtin
287	>	* "synchronized" monitors.
288	>	*
289	>	* Using the first node of a list as a lock does not by itself
290	>	* suffice though: When a node is locked, any update must first
291	>	* validate that it is still the first node after locking it, and
292	>	* retry if not. Because new nodes are always appended to lists,
293	>	* once a node is first in a bin, it remains first until deleted
294	>	* or the bin becomes invalidated (upon resizing).
295	>	*
296	>	* The main disadvantage of per-bin locks is that other update
297	>	* operations on other nodes in a bin list protected by the same
298	>	* lock can stall, for example when user equals() or mapping
299	>	* functions take a long time.  However, statistically, under
300	>	* random hash codes, this is not a common problem.  Ideally, the
301	>	* frequency of nodes in bins follows a Poisson distribution
302	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
303	>	* parameter of about 0.5 on average, given the resizing threshold
304	>	* of 0.75, although with a large variance because of resizing
305	>	* granularity. Ignoring variance, the expected occurrences of
306	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
307	>	* first values are:
308	>	*
309	>	* 0:    0.60653066
310	>	* 1:    0.30326533
311	>	* 2:    0.07581633
312	>	* 3:    0.01263606
313	>	* 4:    0.00157952
314	>	* 5:    0.00015795
315	>	* 6:    0.00001316
316	>	* 7:    0.00000094
317	>	* 8:    0.00000006
318	>	* more: less than 1 in ten million
319	>	*
320	>	* Lock contention probability for two threads accessing distinct
321	>	* elements is roughly 1 / (8 * #elements) under random hashes.
322	>	*
323	>	* Actual hash code distributions encountered in practice
324	>	* sometimes deviate significantly from uniform randomness.  This
325	>	* includes the case when N > (1<<30), so some keys MUST collide.
326	>	* Similarly for dumb or hostile usages in which multiple keys are
327	>	* designed to have identical hash codes or ones that differs only
328	>	* in masked-out high bits. So we use a secondary strategy that
329	>	* applies when the number of nodes in a bin exceeds a
330	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
331	>	* specialized form of red-black trees), bounding search time to
332	>	* O(log N).  Each search step in a TreeBin is at least twice as
333	>	* slow as in a regular list, but given that N cannot exceed
334	>	* (1<<64) (before running out of addresses) this bounds search
335	>	* steps, lock hold times, etc, to reasonable constants (roughly
336	>	* 100 nodes inspected per operation worst case) so long as keys
337	>	* are Comparable (which is very common -- String, Long, etc).
338	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
339	>	* traversal pointers as regular nodes, so can be traversed in
340	>	* iterators in the same way.
341	>	*
342	>	* The table is resized when occupancy exceeds a percentage
343	>	* threshold (nominally, 0.75, but see below).  Any thread
344	>	* noticing an overfull bin may assist in resizing after the
345	>	* initiating thread allocates and sets up the replacement array.
346	>	* However, rather than stalling, these other threads may proceed
347	>	* with insertions etc.  The use of TreeBins shields us from the
348	>	* worst case effects of overfilling while resizes are in
349	>	* progress.  Resizing proceeds by transferring bins, one by one,
350	>	* from the table to the next table. However, threads claim small
351	>	* blocks of indices to transfer (via field transferIndex) before
352	>	* doing so, reducing contention.  A generation stamp in field
353	>	* sizeCtl ensures that resizings do not overlap. Because we are
354	>	* using power-of-two expansion, the elements from each bin must
355	>	* either stay at same index, or move with a power of two
356	>	* offset. We eliminate unnecessary node creation by catching
357	>	* cases where old nodes can be reused because their next fields
358	>	* won't change.  On average, only about one-sixth of them need
359	>	* cloning when a table doubles. The nodes they replace will be
360	>	* garbage collectable as soon as they are no longer referenced by
361	>	* any reader thread that may be in the midst of concurrently
362	>	* traversing table.  Upon transfer, the old table bin contains
363	>	* only a special forwarding node (with hash field "MOVED") that
364	>	* contains the next table as its key. On encountering a
365	>	* forwarding node, access and update operations restart, using
366	>	* the new table.
367	>	*
368	>	* Each bin transfer requires its bin lock, which can stall
369	>	* waiting for locks while resizing. However, because other
370	>	* threads can join in and help resize rather than contend for
371	>	* locks, average aggregate waits become shorter as resizing
372	>	* progresses.  The transfer operation must also ensure that all
373	>	* accessible bins in both the old and new table are usable by any
374	>	* traversal.  This is arranged in part by proceeding from the
375	>	* last bin (table.length - 1) up towards the first.  Upon seeing
376	>	* a forwarding node, traversals (see class Traverser) arrange to
377	>	* move to the new table without revisiting nodes.  To ensure that
378	>	* no intervening nodes are skipped even when moved out of order,
379	>	* a stack (see class TableStack) is created on first encounter of
380	>	* a forwarding node during a traversal, to maintain its place if
381	>	* later processing the current table. The need for these
382	>	* save/restore mechanics is relatively rare, but when one
383	>	* forwarding node is encountered, typically many more will be.
384	>	* So Traversers use a simple caching scheme to avoid creating so
385	>	* many new TableStack nodes. (Thanks to Peter Levart for
386	>	* suggesting use of a stack here.)
387	>	*
388	>	* The traversal scheme also applies to partial traversals of
389	>	* ranges of bins (via an alternate Traverser constructor)
390	>	* to support partitioned aggregate operations.  Also, read-only
391	>	* operations give up if ever forwarded to a null table, which
392	>	* provides support for shutdown-style clearing, which is also not
393	>	* currently implemented.
394	>	*
395	>	* Lazy table initialization minimizes footprint until first use,
396	>	* and also avoids resizings when the first operation is from a
397	>	* putAll, constructor with map argument, or deserialization.
398	>	* These cases attempt to override the initial capacity settings,
399	>	* but harmlessly fail to take effect in cases of races.
400	>	*
401	>	* The element count is maintained using a specialization of
402	>	* LongAdder. We need to incorporate a specialization rather than
403	>	* just use a LongAdder in order to access implicit
404	>	* contention-sensing that leads to creation of multiple
405	>	* CounterCells.  The counter mechanics avoid contention on
406	>	* updates but can encounter cache thrashing if read too
407	>	* frequently during concurrent access. To avoid reading so often,
408	>	* resizing under contention is attempted only upon adding to a
409	>	* bin already holding two or more nodes. Under uniform hash
410	>	* distributions, the probability of this occurring at threshold
411	>	* is around 13%, meaning that only about 1 in 8 puts check
412	>	* threshold (and after resizing, many fewer do so).
413	>	*
414	>	* TreeBins use a special form of comparison for search and
415	>	* related operations (which is the main reason we cannot use
416	>	* existing collections such as TreeMaps). TreeBins contain
417	>	* Comparable elements, but may contain others, as well as
418	>	* elements that are Comparable but not necessarily Comparable for
419	>	* the same T, so we cannot invoke compareTo among them. To handle
420	>	* this, the tree is ordered primarily by hash value, then by
421	>	* Comparable.compareTo order if applicable.  On lookup at a node,
422	>	* if elements are not comparable or compare as 0 then both left
423	>	* and right children may need to be searched in the case of tied
424	>	* hash values. (This corresponds to the full list search that
425	>	* would be necessary if all elements were non-Comparable and had
426	>	* tied hashes.) On insertion, to keep a total ordering (or as
427	>	* close as is required here) across rebalancings, we compare
428	>	* classes and identityHashCodes as tie-breakers. The red-black
429	>	* balancing code is updated from pre-jdk-collections
430	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
431	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
432	>	* Algorithms" (CLR).
433	>	*
434	>	* TreeBins also require an additional locking mechanism.  While
435	>	* list traversal is always possible by readers even during
436	>	* updates, tree traversal is not, mainly because of tree-rotations
437	>	* that may change the root node and/or its linkages.  TreeBins
438	>	* include a simple read-write lock mechanism parasitic on the
439	>	* main bin-synchronization strategy: Structural adjustments
440	>	* associated with an insertion or removal are already bin-locked
441	>	* (and so cannot conflict with other writers) but must wait for
442	>	* ongoing readers to finish. Since there can be only one such
443	>	* waiter, we use a simple scheme using a single "waiter" field to
444	>	* block writers.  However, readers need never block.  If the root
445	>	* lock is held, they proceed along the slow traversal path (via
446	>	* next-pointers) until the lock becomes available or the list is
447	>	* exhausted, whichever comes first. These cases are not fast, but
448	>	* maximize aggregate expected throughput.
449	>	*
450	>	* Maintaining API and serialization compatibility with previous
451	>	* versions of this class introduces several oddities. Mainly: We
452	>	* leave untouched but unused constructor arguments referring to
453	>	* concurrencyLevel. We accept a loadFactor constructor argument,
454	>	* but apply it only to initial table capacity (which is the only
455	>	* time that we can guarantee to honor it.) We also declare an
456	>	* unused "Segment" class that is instantiated in minimal form
457	>	* only when serializing.
458	>	*
459	>	* Also, solely for compatibility with previous versions of this
460	>	* class, it extends AbstractMap, even though all of its methods
461	>	* are overridden, so it is just useless baggage.
462	>	*
463	>	* This file is organized to make things a little easier to follow
464	>	* while reading than they might otherwise: First the main static
465	>	* declarations and utilities, then fields, then main public
466	>	* methods (with a few factorings of multiple public methods into
467	>	* internal ones), then sizing methods, trees, traversers, and
468	>	* bulk operations.
469		*/
470
471		/* ---------------- Constants -------------- */
472
473		/**
474	<	* The default initial capacity for this table,
475	<	* used when not otherwise specified in a constructor.
474	>	* The largest possible table capacity.  This value must be
475	>	* exactly 1<<30 to stay within Java array allocation and indexing
476	>	* bounds for power of two table sizes, and is further required
477	>	* because the top two bits of 32bit hash fields are used for
478	>	* control purposes.
479		*/
480	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
480	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
481
482		/**
483	<	* The default load factor for this table, used when not
484	<	* otherwise specified in a constructor.
483	>	* The default initial table capacity.  Must be a power of 2
484	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
485		*/
486	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
486	>	private static final int DEFAULT_CAPACITY = 16;
487
488		/**
489	<	* The default concurrency level for this table, used when not
490	<	* otherwise specified in a constructor.
489	>	* The largest possible (non-power of two) array size.
490	>	* Needed by toArray and related methods.
491		*/
492	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
492	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
493
494		/**
495	<	* The maximum capacity, used if a higher value is implicitly
496	<	* specified by either of the constructors with arguments.  MUST
123	<	* be a power of two <= 1<<30 to ensure that entries are indexable
124	<	* using ints.
495	>	* The default concurrency level for this table. Unused but
496	>	* defined for compatibility with previous versions of this class.
497		*/
498	<	static final int MAXIMUM_CAPACITY = 1 << 30;
498	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
499
500		/**
501	<	* The minimum capacity for per-segment tables.  Must be a power
502	<	* of two, at least two to avoid immediate resizing on next use
503	<	* after lazy construction.
501	>	* The load factor for this table. Overrides of this value in
502	>	* constructors affect only the initial table capacity.  The
503	>	* actual floating point value isn't normally used -- it is
504	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
505	>	* the associated resizing threshold.
506		*/
507	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
507	>	private static final float LOAD_FACTOR = 0.75f;
508
509		/**
510	<	* The maximum number of segments to allow; used to bound
511	<	* constructor arguments. Must be power of two less than 1 << 24.
510	>	* The bin count threshold for using a tree rather than list for a
511	>	* bin.  Bins are converted to trees when adding an element to a
512	>	* bin with at least this many nodes. The value must be greater
513	>	* than 2, and should be at least 8 to mesh with assumptions in
514	>	* tree removal about conversion back to plain bins upon
515	>	* shrinkage.
516		*/
517	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
517	>	static final int TREEIFY_THRESHOLD = 8;
518
519		/**
520	<	* Number of unsynchronized retries in size and containsValue
521	<	* methods before resorting to locking. This is used to avoid
522	<	* unbounded retries if tables undergo continuous modification
145	<	* which would make it impossible to obtain an accurate result.
520	>	* The bin count threshold for untreeifying a (split) bin during a
521	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
522	>	* most 6 to mesh with shrinkage detection under removal.
523		*/
524	<	static final int RETRIES_BEFORE_LOCK = 2;
148	<
149	<	/* ---------------- Fields -------------- */
524	>	static final int UNTREEIFY_THRESHOLD = 6;
525
526		/**
527	<	* Mask value for indexing into segments. The upper bits of a
528	<	* key's hash code are used to choose the segment.
527	>	* The smallest table capacity for which bins may be treeified.
528	>	* (Otherwise the table is resized if too many nodes in a bin.)
529	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
530	>	* conflicts between resizing and treeification thresholds.
531		*/
532	<	final int segmentMask;
532	>	static final int MIN_TREEIFY_CAPACITY = 64;
533
534		/**
535	<	* Shift value for indexing within segments.
535	>	* Minimum number of rebinnings per transfer step. Ranges are
536	>	* subdivided to allow multiple resizer threads.  This value
537	>	* serves as a lower bound to avoid resizers encountering
538	>	* excessive memory contention.  The value should be at least
539	>	* DEFAULT_CAPACITY.
540		*/
541	<	final int segmentShift;
541	>	private static final int MIN_TRANSFER_STRIDE = 16;
542
543		/**
544	<	* The segments, each of which is a specialized hash table.
544	>	* The number of bits used for generation stamp in sizeCtl.
545	>	* Must be at least 6 for 32bit arrays.
546		*/
547	<	final Segment<K,V>[] segments;
547	>	private static final int RESIZE_STAMP_BITS = 16;
548
549	<	transient Set<K> keySet;
550	<	transient Set<Map.Entry<K,V>> entrySet;
551	<	transient Collection<V> values;
549	>	/**
550	>	* The maximum number of threads that can help resize.
551	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
552	>	*/
553	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
554
555		/**
556	<	* ConcurrentHashMap list entry. Note that this is never exported
557	<	* out as a user-visible Map.Entry.
556	>	* The bit shift for recording size stamp in sizeCtl.
557	>	*/
558	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
559	>
560	>	/*
561	>	* Encodings for Node hash fields. See above for explanation.
562	>	*/
563	>	static final int MOVED     = -1; // hash for forwarding nodes
564	>	static final int TREEBIN   = -2; // hash for roots of trees
565	>	static final int RESERVED  = -3; // hash for transient reservations
566	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
567	>
568	>	/** Number of CPUS, to place bounds on some sizings */
569	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
570	>
571	>	/**
572	>	* Serialized pseudo-fields, provided only for jdk7 compatibility.
573	>	* @serialField segments Segment[]
574	>	*   The segments, each of which is a specialized hash table.
575	>	* @serialField segmentMask int
576	>	*   Mask value for indexing into segments. The upper bits of a
577	>	*   key's hash code are used to choose the segment.
578	>	* @serialField segmentShift int
579	>	*   Shift value for indexing within segments.
580	>	*/
581	>	private static final ObjectStreamField[] serialPersistentFields = {
582	>	new ObjectStreamField("segments", Segment[].class),
583	>	new ObjectStreamField("segmentMask", Integer.TYPE),
584	>	new ObjectStreamField("segmentShift", Integer.TYPE),
585	>	};
586	>
587	>	/* ---------------- Nodes -------------- */
588	>
589	>	/**
590	>	* Key-value entry.  This class is never exported out as a
591	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
592	>	* MapEntry below), but can be used for read-only traversals used
593	>	* in bulk tasks.  Subclasses of Node with a negative hash field
594	>	* are special, and contain null keys and values (but are never
595	>	* exported).  Otherwise, keys and vals are never null.
596		*/
597	<	static final class HashEntry<K,V> {
597	>	static class Node<K,V> implements Map.Entry<K,V> {
598		final int hash;
599		final K key;
600	<	volatile V value;
601	<	volatile HashEntry<K,V> next;
600	>	volatile V val;
601	>	volatile Node<K,V> next;
602
603	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
603	>	Node(int hash, K key, V val) {
604		this.hash = hash;
605		this.key = key;
606	<	this.value = value;
606	>	this.val = val;
607	>	}
608	>
609	>	Node(int hash, K key, V val, Node<K,V> next) {
610	>	this(hash, key, val);
611		this.next = next;
612		}
613
614	+	public final K getKey()     { return key; }
615	+	public final V getValue()   { return val; }
616	+	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
617	+	public final String toString() {
618	+	return Helpers.mapEntryToString(key, val);
619	+	}
620	+	public final V setValue(V value) {
621	+	throw new UnsupportedOperationException();
622	+	}
623	+
624	+	public final boolean equals(Object o) {
625	+	Object k, v, u; Map.Entry<?,?> e;
626	+	return ((o instanceof Map.Entry) &&
627	+	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
628	+	(v = e.getValue()) != null &&
629	+	(k == key || k.equals(key)) &&
630	+	(v == (u = val) || v.equals(u)));
631	+	}
632	+
633		/**
634	<	* Sets next field with volatile write semantics.  (See above
190	<	* about use of putOrderedObject.)
634	>	* Virtualized support for map.get(); overridden in subclasses.
635		*/
636	<	final void setNext(HashEntry<K,V> n) {
637	<	UNSAFE.putOrderedObject(this, nextOffset, n);
636	>	Node<K,V> find(int h, Object k) {
637	>	Node<K,V> e = this;
638	>	if (k != null) {
639	>	do {
640	>	K ek;
641	>	if (e.hash == h &&
642	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
643	>	return e;
644	>	} while ((e = e.next) != null);
645	>	}
646	>	return null;
647		}
648	+	}
649
650	<	// Unsafe mechanics
651	<	static final sun.misc.Unsafe UNSAFE;
652	<	static final long nextOffset;
653	<	static {
654	<	try {
655	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
656	<	Class k = HashEntry.class;
657	<	nextOffset = UNSAFE.objectFieldOffset
658	<	(k.getDeclaredField("next"));
659	<	} catch (Exception e) {
660	<	throw new Error(e);
650	>	/* ---------------- Static utilities -------------- */
651	>
652	>	/**
653	>	* Spreads (XORs) higher bits of hash to lower and also forces top
654	>	* bit to 0. Because the table uses power-of-two masking, sets of
655	>	* hashes that vary only in bits above the current mask will
656	>	* always collide. (Among known examples are sets of Float keys
657	>	* holding consecutive whole numbers in small tables.)  So we
658	>	* apply a transform that spreads the impact of higher bits
659	>	* downward. There is a tradeoff between speed, utility, and
660	>	* quality of bit-spreading. Because many common sets of hashes
661	>	* are already reasonably distributed (so don't benefit from
662	>	* spreading), and because we use trees to handle large sets of
663	>	* collisions in bins, we just XOR some shifted bits in the
664	>	* cheapest possible way to reduce systematic lossage, as well as
665	>	* to incorporate impact of the highest bits that would otherwise
666	>	* never be used in index calculations because of table bounds.
667	>	*/
668	>	static final int spread(int h) {
669	>	return (h ^ (h >>> 16)) & HASH_BITS;
670	>	}
671	>
672	>	/**
673	>	* Returns a power of two table size for the given desired capacity.
674	>	* See Hackers Delight, sec 3.2
675	>	*/
676	>	private static final int tableSizeFor(int c) {
677	>	int n = c - 1;
678	>	n |= n >>> 1;
679	>	n |= n >>> 2;
680	>	n |= n >>> 4;
681	>	n |= n >>> 8;
682	>	n |= n >>> 16;
683	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
684	>	}
685	>
686	>	/**
687	>	* Returns x's Class if it is of the form "class C implements
688	>	* Comparable<C>", else null.
689	>	*/
690	>	static Class<?> comparableClassFor(Object x) {
691	>	if (x instanceof Comparable) {
692	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
693	>	if ((c = x.getClass()) == String.class) // bypass checks
694	>	return c;
695	>	if ((ts = c.getGenericInterfaces()) != null) {
696	>	for (int i = 0; i < ts.length; ++i) {
697	>	if (((t = ts[i]) instanceof ParameterizedType) &&
698	>	((p = (ParameterizedType)t).getRawType() ==
699	>	Comparable.class) &&
700	>	(as = p.getActualTypeArguments()) != null &&
701	>	as.length == 1 && as[0] == c) // type arg is c
702	>	return c;
703	>	}
704		}
705		}
706	+	return null;
707		}
708
709		/**
710	<	* Gets the ith element of given table (if nonnull) with volatile
711	<	* read semantics.
710	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
711	>	* class), else 0.
712	>	*/
713	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
714	>	static int compareComparables(Class<?> kc, Object k, Object x) {
715	>	return (x == null || x.getClass() != kc ? 0 :
716	>	((Comparable)k).compareTo(x));
717	>	}
718	>
719	>	/* ---------------- Table element access -------------- */
720	>
721	>	/*
722	>	* Atomic access methods are used for table elements as well as
723	>	* elements of in-progress next table while resizing.  All uses of
724	>	* the tab arguments must be null checked by callers.  All callers
725	>	* also paranoically precheck that tab's length is not zero (or an
726	>	* equivalent check), thus ensuring that any index argument taking
727	>	* the form of a hash value anded with (length - 1) is a valid
728	>	* index.  Note that, to be correct wrt arbitrary concurrency
729	>	* errors by users, these checks must operate on local variables,
730	>	* which accounts for some odd-looking inline assignments below.
731	>	* Note that calls to setTabAt always occur within locked regions,
732	>	* and so require only release ordering.
733		*/
734	+
735		@SuppressWarnings("unchecked")
736	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
737	<	return tab == null? null :
738	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
739	<	(tab, ((long)i << TSHIFT) + TBASE);
736	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
737	>	return (Node<K,V>)U.getObjectAcquire(tab, ((long)i << ASHIFT) + ABASE);
738	>	}
739	>
740	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
741	>	Node<K,V> c, Node<K,V> v) {
742	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
743		}
744
745	+	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
746	+	U.putObjectRelease(tab, ((long)i << ASHIFT) + ABASE, v);
747	+	}
748	+
749	+	/* ---------------- Fields -------------- */
750	+
751		/**
752	<	* Sets the ith element of given table, with volatile write
753	<	* semantics. (See above about use of putOrderedObject.)
752	>	* The array of bins. Lazily initialized upon first insertion.
753	>	* Size is always a power of two. Accessed directly by iterators.
754		*/
755	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
227	<	HashEntry<K,V> e) {
228	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
229	<	}
755	>	transient volatile Node<K,V>[] table;
756
757		/**
758	<	* Applies a supplemental hash function to a given hashCode, which
233	<	* defends against poor quality hash functions.  This is critical
234	<	* because ConcurrentHashMap uses power-of-two length hash tables,
235	<	* that otherwise encounter collisions for hashCodes that do not
236	<	* differ in lower or upper bits.
758	>	* The next table to use; non-null only while resizing.
759		*/
760	<	private static int hash(int h) {
239	<	// Spread bits to regularize both segment and index locations,
240	<	// using variant of single-word Wang/Jenkins hash.
241	<	h += (h <<  15) ^ 0xffffcd7d;
242	<	h ^= (h >>> 10);
243	<	h += (h <<   3);
244	<	h ^= (h >>>  6);
245	<	h += (h <<   2) + (h << 14);
246	<	return h ^ (h >>> 16);
247	<	}
760	>	private transient volatile Node<K,V>[] nextTable;
761
762		/**
763	<	* Segments are specialized versions of hash tables.  This
764	<	* subclasses from ReentrantLock opportunistically, just to
765	<	* simplify some locking and avoid separate construction.
763	>	* Base counter value, used mainly when there is no contention,
764	>	* but also as a fallback during table initialization
765	>	* races. Updated via CAS.
766		*/
767	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
255	<	/*
256	<	* Segments maintain a table of entry lists that are always
257	<	* kept in a consistent state, so can be read (via volatile
258	<	* reads of segments and tables) without locking.  This
259	<	* requires replicating nodes when necessary during table
260	<	* resizing, so the old lists can be traversed by readers
261	<	* still using old version of table.
262	<	*
263	<	* This class defines only mutative methods requiring locking.
264	<	* Except as noted, the methods of this class perform the
265	<	* per-segment versions of ConcurrentHashMap methods.  (Other
266	<	* methods are integrated directly into ConcurrentHashMap
267	<	* methods.) These mutative methods use a form of controlled
268	<	* spinning on contention via methods scanAndLock and
269	<	* scanAndLockForPut. These intersperse tryLocks with
270	<	* traversals to locate nodes.  The main benefit is to absorb
271	<	* cache misses (which are very common for hash tables) while
272	<	* obtaining locks so that traversal is faster once
273	<	* acquired. We do not actually use the found nodes since they
274	<	* must be re-acquired under lock anyway to ensure sequential
275	<	* consistency of updates (and in any case may be undetectably
276	<	* stale), but they will normally be much faster to re-locate.
277	<	* Also, scanAndLockForPut speculatively creates a fresh node
278	<	* to use in put if no node is found.
279	<	*/
767	>	private transient volatile long baseCount;
768
769	<	private static final long serialVersionUID = 2249069246763182397L;
769	>	/**
770	>	* Table initialization and resizing control.  When negative, the
771	>	* table is being initialized or resized: -1 for initialization,
772	>	* else -(1 + the number of active resizing threads).  Otherwise,
773	>	* when table is null, holds the initial table size to use upon
774	>	* creation, or 0 for default. After initialization, holds the
775	>	* next element count value upon which to resize the table.
776	>	*/
777	>	private transient volatile int sizeCtl;
778
779	<	/**
780	<	* The maximum number of times to tryLock in a prescan before
781	<	* possibly blocking on acquire in preparation for a locked
782	<	* segment operation. On multiprocessors, using a bounded
287	<	* number of retries maintains cache acquired while locating
288	<	* nodes.
289	<	*/
290	<	static final int MAX_SCAN_RETRIES =
291	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
779	>	/**
780	>	* The next table index (plus one) to split while resizing.
781	>	*/
782	>	private transient volatile int transferIndex;
783
784	<	/**
785	<	* The per-segment table. Elements are accessed via
786	<	* entryAt/setEntryAt providing volatile semantics.
787	<	*/
297	<	transient volatile HashEntry<K,V>[] table;
784	>	/**
785	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
786	>	*/
787	>	private transient volatile int cellsBusy;
788
789	<	/**
790	<	* The number of elements. Accessed only either within locks
791	<	* or among other volatile reads that maintain visibility.
792	<	*/
303	<	transient int count;
789	>	/**
790	>	* Table of counter cells. When non-null, size is a power of 2.
791	>	*/
792	>	private transient volatile CounterCell[] counterCells;
793
794	<	/**
795	<	* The total number of insertions and removals in this
796	<	* segment.  Even though this may overflows 32 bits, it
797	<	* provides sufficient accuracy for stability checks in CHM
309	<	* isEmpty() and size() methods.  Accessed only either within
310	<	* locks or among other volatile reads that maintain
311	<	* visibility.
312	<	*/
313	<	transient int modCount;
794	>	// views
795	>	private transient KeySetView<K,V> keySet;
796	>	private transient ValuesView<K,V> values;
797	>	private transient EntrySetView<K,V> entrySet;
798
315	–	/**
316	–	* The table is rehashed when its size exceeds this threshold.
317	–	* (The value of this field is always <tt>(int)(capacity *
318	–	* loadFactor)</tt>.)
319	–	*/
320	–	transient int threshold;
799
800	<	/**
323	<	* The load factor for the hash table.  Even though this value
324	<	* is same for all segments, it is replicated to avoid needing
325	<	* links to outer object.
326	<	* @serial
327	<	*/
328	<	final float loadFactor;
800	>	/* ---------------- Public operations -------------- */
801
802	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
803	<	this.loadFactor = lf;
804	<	this.threshold = threshold;
805	<	this.table = tab;
806	<	}
802	>	/**
803	>	* Creates a new, empty map with the default initial table size (16).
804	>	*/
805	>	public ConcurrentHashMap() {
806	>	}
807
808	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
809	<	HashEntry<K,V> node = tryLock() ? null :
810	<	scanAndLockForPut(key, hash, value);
811	<	V oldValue;
812	<	try {
813	<	HashEntry<K,V>[] tab = table;
814	<	int index = (tab.length - 1) & hash;
815	<	HashEntry<K,V> first = entryAt(tab, index);
816	<	for (HashEntry<K,V> e = first;;) {
817	<	if (e != null) {
818	<	K k;
819	<	if ((k = e.key) == key ||
820	<	(e.hash == hash && key.equals(k))) {
821	<	oldValue = e.value;
822	<	if (!onlyIfAbsent)
823	<	e.value = value;
824	<	break;
825	<	}
826	<	e = e.next;
827	<	}
828	<	else {
829	<	if (node != null)
830	<	node.setNext(first);
831	<	else
832	<	node = new HashEntry<K,V>(hash, key, value, first);
833	<	int c = count + 1;
834	<	if (c > threshold && first != null &&
835	<	tab.length < MAXIMUM_CAPACITY)
836	<	rehash(node);
837	<	else
838	<	setEntryAt(tab, index, node);
839	<	++modCount;
840	<	count = c;
841	<	oldValue = null;
842	<	break;
843	<	}
844	<	}
845	<	} finally {
846	<	unlock();
808	>	/**
809	>	* Creates a new, empty map with an initial table size
810	>	* accommodating the specified number of elements without the need
811	>	* to dynamically resize.
812	>	*
813	>	* @param initialCapacity The implementation performs internal
814	>	* sizing to accommodate this many elements.
815	>	* @throws IllegalArgumentException if the initial capacity of
816	>	* elements is negative
817	>	*/
818	>	public ConcurrentHashMap(int initialCapacity) {
819	>	if (initialCapacity < 0)
820	>	throw new IllegalArgumentException();
821	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
822	>	MAXIMUM_CAPACITY :
823	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
824	>	this.sizeCtl = cap;
825	>	}
826	>
827	>	/**
828	>	* Creates a new map with the same mappings as the given map.
829	>	*
830	>	* @param m the map
831	>	*/
832	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
833	>	this.sizeCtl = DEFAULT_CAPACITY;
834	>	putAll(m);
835	>	}
836	>
837	>	/**
838	>	* Creates a new, empty map with an initial table size based on
839	>	* the given number of elements ({@code initialCapacity}) and
840	>	* initial table density ({@code loadFactor}).
841	>	*
842	>	* @param initialCapacity the initial capacity. The implementation
843	>	* performs internal sizing to accommodate this many elements,
844	>	* given the specified load factor.
845	>	* @param loadFactor the load factor (table density) for
846	>	* establishing the initial table size
847	>	* @throws IllegalArgumentException if the initial capacity of
848	>	* elements is negative or the load factor is nonpositive
849	>	*
850	>	* @since 1.6
851	>	*/
852	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
853	>	this(initialCapacity, loadFactor, 1);
854	>	}
855	>
856	>	/**
857	>	* Creates a new, empty map with an initial table size based on
858	>	* the given number of elements ({@code initialCapacity}), table
859	>	* density ({@code loadFactor}), and number of concurrently
860	>	* updating threads ({@code concurrencyLevel}).
861	>	*
862	>	* @param initialCapacity the initial capacity. The implementation
863	>	* performs internal sizing to accommodate this many elements,
864	>	* given the specified load factor.
865	>	* @param loadFactor the load factor (table density) for
866	>	* establishing the initial table size
867	>	* @param concurrencyLevel the estimated number of concurrently
868	>	* updating threads. The implementation may use this value as
869	>	* a sizing hint.
870	>	* @throws IllegalArgumentException if the initial capacity is
871	>	* negative or the load factor or concurrencyLevel are
872	>	* nonpositive
873	>	*/
874	>	public ConcurrentHashMap(int initialCapacity,
875	>	float loadFactor, int concurrencyLevel) {
876	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
877	>	throw new IllegalArgumentException();
878	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
879	>	initialCapacity = concurrencyLevel;   // as estimated threads
880	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
881	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
882	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
883	>	this.sizeCtl = cap;
884	>	}
885	>
886	>	// Original (since JDK1.2) Map methods
887	>
888	>	/**
889	>	* {@inheritDoc}
890	>	*/
891	>	public int size() {
892	>	long n = sumCount();
893	>	return ((n < 0L) ? 0 :
894	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
895	>	(int)n);
896	>	}
897	>
898	>	/**
899	>	* {@inheritDoc}
900	>	*/
901	>	public boolean isEmpty() {
902	>	return sumCount() <= 0L; // ignore transient negative values
903	>	}
904	>
905	>	/**
906	>	* Returns the value to which the specified key is mapped,
907	>	* or {@code null} if this map contains no mapping for the key.
908	>	*
909	>	* <p>More formally, if this map contains a mapping from a key
910	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
911	>	* then this method returns {@code v}; otherwise it returns
912	>	* {@code null}.  (There can be at most one such mapping.)
913	>	*
914	>	* @throws NullPointerException if the specified key is null
915	>	*/
916	>	public V get(Object key) {
917	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
918	>	int h = spread(key.hashCode());
919	>	if ((tab = table) != null && (n = tab.length) > 0 &&
920	>	(e = tabAt(tab, (n - 1) & h)) != null) {
921	>	if ((eh = e.hash) == h) {
922	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
923	>	return e.val;
924	>	}
925	>	else if (eh < 0)
926	>	return (p = e.find(h, key)) != null ? p.val : null;
927	>	while ((e = e.next) != null) {
928	>	if (e.hash == h &&
929	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
930	>	return e.val;
931		}
376	–	return oldValue;
932		}
933	+	return null;
934	+	}
935
936	<	/**
937	<	* Doubles size of table and repacks entries, also adding the
938	<	* given node to new table
939	<	*/
940	<	@SuppressWarnings("unchecked")
941	<	private void rehash(HashEntry<K,V> node) {
942	<	/*
943	<	* Reclassify nodes in each list to new table.  Because we
944	<	* are using power-of-two expansion, the elements from
945	<	* each bin must either stay at same index, or move with a
946	<	* power of two offset. We eliminate unnecessary node
947	<	* creation by catching cases where old nodes can be
391	<	* reused because their next fields won't change.
392	<	* Statistically, at the default threshold, only about
393	<	* one-sixth of them need cloning when a table
394	<	* doubles. The nodes they replace will be garbage
395	<	* collectable as soon as they are no longer referenced by
396	<	* any reader thread that may be in the midst of
397	<	* concurrently traversing table. Entry accesses use plain
398	<	* array indexing because they are followed by volatile
399	<	* table write.
400	<	*/
401	<	HashEntry<K,V>[] oldTable = table;
402	<	int oldCapacity = oldTable.length;
403	<	int newCapacity = oldCapacity << 1;
404	<	threshold = (int)(newCapacity * loadFactor);
405	<	HashEntry<K,V>[] newTable =
406	<	(HashEntry<K,V>[]) new HashEntry[newCapacity];
407	<	int sizeMask = newCapacity - 1;
408	<	for (int i = 0; i < oldCapacity ; i++) {
409	<	HashEntry<K,V> e = oldTable[i];
410	<	if (e != null) {
411	<	HashEntry<K,V> next = e.next;
412	<	int idx = e.hash & sizeMask;
413	<	if (next == null)   //  Single node on list
414	<	newTable[idx] = e;
415	<	else { // Reuse consecutive sequence at same slot
416	<	HashEntry<K,V> lastRun = e;
417	<	int lastIdx = idx;
418	<	for (HashEntry<K,V> last = next;
419	<	last != null;
420	<	last = last.next) {
421	<	int k = last.hash & sizeMask;
422	<	if (k != lastIdx) {
423	<	lastIdx = k;
424	<	lastRun = last;
425	<	}
426	<	}
427	<	newTable[lastIdx] = lastRun;
428	<	// Clone remaining nodes
429	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
430	<	V v = p.value;
431	<	int h = p.hash;
432	<	int k = h & sizeMask;
433	<	HashEntry<K,V> n = newTable[k];
434	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
435	<	}
436	<	}
437	<	}
438	<	}
439	<	int nodeIndex = node.hash & sizeMask; // add the new node
440	<	node.setNext(newTable[nodeIndex]);
441	<	newTable[nodeIndex] = node;
442	<	table = newTable;
443	<	}
444	<
445	<	/**
446	<	* Scans for a node containing given key while trying to
447	<	* acquire lock, creating and returning one if not found. Upon
448	<	* return, guarantees that lock is held.
449	<	*
450	<	* @return a new node if key not found, else null
451	<	*/
452	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
453	<	HashEntry<K,V> first = entryForHash(this, hash);
454	<	HashEntry<K,V> e = first;
455	<	HashEntry<K,V> node = null;
456	<	int retries = -1; // negative while locating node
457	<	while (!tryLock()) {
458	<	HashEntry<K,V> f; // to recheck first below
459	<	if (retries < 0) {
460	<	if (e == null) {
461	<	if (node == null) // speculatively create node
462	<	node = new HashEntry<K,V>(hash, key, value, null);
463	<	retries = 0;
464	<	}
465	<	else if (key.equals(e.key))
466	<	retries = 0;
467	<	else
468	<	e = e.next;
469	<	}
470	<	else if (++retries > MAX_SCAN_RETRIES) {
471	<	lock();
472	<	break;
473	<	}
474	<	else if ((retries & 1) == 0 &&
475	<	(f = entryForHash(this, hash)) != first) {
476	<	e = first = f; // re-traverse if entry changed
477	<	retries = -1;
478	<	}
479	<	}
480	<	return node;
481	<	}
936	>	/**
937	>	* Tests if the specified object is a key in this table.
938	>	*
939	>	* @param  key possible key
940	>	* @return {@code true} if and only if the specified object
941	>	*         is a key in this table, as determined by the
942	>	*         {@code equals} method; {@code false} otherwise
943	>	* @throws NullPointerException if the specified key is null
944	>	*/
945	>	public boolean containsKey(Object key) {
946	>	return get(key) != null;
947	>	}
948
949	<	/**
950	<	* Scans for a node containing the given key while trying to
951	<	* acquire lock for a remove or replace operation. Upon
952	<	* return, guarantees that lock is held.  Note that we must
953	<	* lock even if the key is not found, to ensure sequential
954	<	* consistency of updates.
955	<	*/
956	<	private void scanAndLock(Object key, int hash) {
957	<	// similar to but simpler than scanAndLockForPut
958	<	HashEntry<K,V> first = entryForHash(this, hash);
959	<	HashEntry<K,V> e = first;
960	<	int retries = -1;
961	<	while (!tryLock()) {
962	<	HashEntry<K,V> f;
963	<	if (retries < 0) {
964	<	if (e == null || key.equals(e.key))
965	<	retries = 0;
966	<	else
967	<	e = e.next;
968	<	}
503	<	else if (++retries > MAX_SCAN_RETRIES) {
504	<	lock();
505	<	break;
506	<	}
507	<	else if ((retries & 1) == 0 &&
508	<	(f = entryForHash(this, hash)) != first) {
509	<	e = first = f;
510	<	retries = -1;
511	<	}
949	>	/**
950	>	* Returns {@code true} if this map maps one or more keys to the
951	>	* specified value. Note: This method may require a full traversal
952	>	* of the map, and is much slower than method {@code containsKey}.
953	>	*
954	>	* @param value value whose presence in this map is to be tested
955	>	* @return {@code true} if this map maps one or more keys to the
956	>	*         specified value
957	>	* @throws NullPointerException if the specified value is null
958	>	*/
959	>	public boolean containsValue(Object value) {
960	>	if (value == null)
961	>	throw new NullPointerException();
962	>	Node<K,V>[] t;
963	>	if ((t = table) != null) {
964	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
965	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
966	>	V v;
967	>	if ((v = p.val) == value || (v != null && value.equals(v)))
968	>	return true;
969		}
970		}
971	+	return false;
972	+	}
973
974	<	/**
975	<	* Remove; match on key only if value null, else match both.
976	<	*/
977	<	final V remove(Object key, int hash, Object value) {
978	<	if (!tryLock())
979	<	scanAndLock(key, hash);
980	<	V oldValue = null;
981	<	try {
982	<	HashEntry<K,V>[] tab = table;
983	<	int index = (tab.length - 1) & hash;
984	<	HashEntry<K,V> e = entryAt(tab, index);
985	<	HashEntry<K,V> pred = null;
986	<	while (e != null) {
987	<	K k;
988	<	HashEntry<K,V> next = e.next;
989	<	if ((k = e.key) == key ||
990	<	(e.hash == hash && key.equals(k))) {
991	<	V v = e.value;
992	<	if (value == null || value == v || value.equals(v)) {
993	<	if (pred == null)
994	<	setEntryAt(tab, index, next);
995	<	else
996	<	pred.setNext(next);
997	<	++modCount;
998	<	--count;
999	<	oldValue = v;
974	>	/**
975	>	* Maps the specified key to the specified value in this table.
976	>	* Neither the key nor the value can be null.
977	>	*
978	>	* <p>The value can be retrieved by calling the {@code get} method
979	>	* with a key that is equal to the original key.
980	>	*
981	>	* @param key key with which the specified value is to be associated
982	>	* @param value value to be associated with the specified key
983	>	* @return the previous value associated with {@code key}, or
984	>	*         {@code null} if there was no mapping for {@code key}
985	>	* @throws NullPointerException if the specified key or value is null
986	>	*/
987	>	public V put(K key, V value) {
988	>	return putVal(key, value, false);
989	>	}
990	>
991	>	/** Implementation for put and putIfAbsent */
992	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
993	>	if (key == null || value == null) throw new NullPointerException();
994	>	int hash = spread(key.hashCode());
995	>	int binCount = 0;
996	>	for (Node<K,V>[] tab = table;;) {
997	>	Node<K,V> f; int n, i, fh; K fk; V fv;
998	>	if (tab == null || (n = tab.length) == 0)
999	>	tab = initTable();
1000	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
1001	>	if (casTabAt(tab, i, null, new Node<K,V>(hash, key, value)))
1002	>	break;                   // no lock when adding to empty bin
1003	>	}
1004	>	else if ((fh = f.hash) == MOVED)
1005	>	tab = helpTransfer(tab, f);
1006	>	else if (onlyIfAbsent // check first node without acquiring lock
1007	>	&& fh == hash
1008	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
1009	>	&& (fv = f.val) != null)
1010	>	return fv;
1011	>	else {
1012	>	V oldVal = null;
1013	>	synchronized (f) {
1014	>	if (tabAt(tab, i) == f) {
1015	>	if (fh >= 0) {
1016	>	binCount = 1;
1017	>	for (Node<K,V> e = f;; ++binCount) {
1018	>	K ek;
1019	>	if (e.hash == hash &&
1020	>	((ek = e.key) == key ||
1021	>	(ek != null && key.equals(ek)))) {
1022	>	oldVal = e.val;
1023	>	if (!onlyIfAbsent)
1024	>	e.val = value;
1025	>	break;
1026	>	}
1027	>	Node<K,V> pred = e;
1028	>	if ((e = e.next) == null) {
1029	>	pred.next = new Node<K,V>(hash, key, value);
1030	>	break;
1031	>	}
1032	>	}
1033		}
1034	<	break;
1034	>	else if (f instanceof TreeBin) {
1035	>	Node<K,V> p;
1036	>	binCount = 2;
1037	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1038	>	value)) != null) {
1039	>	oldVal = p.val;
1040	>	if (!onlyIfAbsent)
1041	>	p.val = value;
1042	>	}
1043	>	}
1044	>	else if (f instanceof ReservationNode)
1045	>	throw new IllegalStateException("Recursive update");
1046		}
544	–	pred = e;
545	–	e = next;
1047		}
1048	<	} finally {
1049	<	unlock();
1048	>	if (binCount != 0) {
1049	>	if (binCount >= TREEIFY_THRESHOLD)
1050	>	treeifyBin(tab, i);
1051	>	if (oldVal != null)
1052	>	return oldVal;
1053	>	break;
1054	>	}
1055		}
550	–	return oldValue;
1056		}
1057	+	addCount(1L, binCount);
1058	+	return null;
1059	+	}
1060
1061	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
1062	<	if (!tryLock())
1063	<	scanAndLock(key, hash);
1064	<	boolean replaced = false;
1065	<	try {
1066	<	HashEntry<K,V> e;
1067	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1068	<	K k;
1069	<	if ((k = e.key) == key ||
1070	<	(e.hash == hash && key.equals(k))) {
1071	<	if (oldValue.equals(e.value)) {
1072	<	e.value = newValue;
1073	<	replaced = true;
1061	>	/**
1062	>	* Copies all of the mappings from the specified map to this one.
1063	>	* These mappings replace any mappings that this map had for any of the
1064	>	* keys currently in the specified map.
1065	>	*
1066	>	* @param m mappings to be stored in this map
1067	>	*/
1068	>	public void putAll(Map<? extends K, ? extends V> m) {
1069	>	tryPresize(m.size());
1070	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1071	>	putVal(e.getKey(), e.getValue(), false);
1072	>	}
1073	>
1074	>	/**
1075	>	* Removes the key (and its corresponding value) from this map.
1076	>	* This method does nothing if the key is not in the map.
1077	>	*
1078	>	* @param  key the key that needs to be removed
1079	>	* @return the previous value associated with {@code key}, or
1080	>	*         {@code null} if there was no mapping for {@code key}
1081	>	* @throws NullPointerException if the specified key is null
1082	>	*/
1083	>	public V remove(Object key) {
1084	>	return replaceNode(key, null, null);
1085	>	}
1086	>
1087	>	/**
1088	>	* Implementation for the four public remove/replace methods:
1089	>	* Replaces node value with v, conditional upon match of cv if
1090	>	* non-null.  If resulting value is null, delete.
1091	>	*/
1092	>	final V replaceNode(Object key, V value, Object cv) {
1093	>	int hash = spread(key.hashCode());
1094	>	for (Node<K,V>[] tab = table;;) {
1095	>	Node<K,V> f; int n, i, fh;
1096	>	if (tab == null || (n = tab.length) == 0 ||
1097	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1098	>	break;
1099	>	else if ((fh = f.hash) == MOVED)
1100	>	tab = helpTransfer(tab, f);
1101	>	else {
1102	>	V oldVal = null;
1103	>	boolean validated = false;
1104	>	synchronized (f) {
1105	>	if (tabAt(tab, i) == f) {
1106	>	if (fh >= 0) {
1107	>	validated = true;
1108	>	for (Node<K,V> e = f, pred = null;;) {
1109	>	K ek;
1110	>	if (e.hash == hash &&
1111	>	((ek = e.key) == key ||
1112	>	(ek != null && key.equals(ek)))) {
1113	>	V ev = e.val;
1114	>	if (cv == null || cv == ev ||
1115	>	(ev != null && cv.equals(ev))) {
1116	>	oldVal = ev;
1117	>	if (value != null)
1118	>	e.val = value;
1119	>	else if (pred != null)
1120	>	pred.next = e.next;
1121	>	else
1122	>	setTabAt(tab, i, e.next);
1123	>	}
1124	>	break;
1125	>	}
1126	>	pred = e;
1127	>	if ((e = e.next) == null)
1128	>	break;
1129	>	}
1130		}
1131	<	break;
1131	>	else if (f instanceof TreeBin) {
1132	>	validated = true;
1133	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1134	>	TreeNode<K,V> r, p;
1135	>	if ((r = t.root) != null &&
1136	>	(p = r.findTreeNode(hash, key, null)) != null) {
1137	>	V pv = p.val;
1138	>	if (cv == null || cv == pv ||
1139	>	(pv != null && cv.equals(pv))) {
1140	>	oldVal = pv;
1141	>	if (value != null)
1142	>	p.val = value;
1143	>	else if (t.removeTreeNode(p))
1144	>	setTabAt(tab, i, untreeify(t.first));
1145	>	}
1146	>	}
1147	>	}
1148	>	else if (f instanceof ReservationNode)
1149	>	throw new IllegalStateException("Recursive update");
1150		}
1151		}
1152	<	} finally {
1153	<	unlock();
1152	>	if (validated) {
1153	>	if (oldVal != null) {
1154	>	if (value == null)
1155	>	addCount(-1L, -1);
1156	>	return oldVal;
1157	>	}
1158	>	break;
1159	>	}
1160		}
573	–	return replaced;
1161		}
1162	+	return null;
1163	+	}
1164
1165	<	final V replace(K key, int hash, V value) {
1166	<	if (!tryLock())
1167	<	scanAndLock(key, hash);
1168	<	V oldValue = null;
1169	<	try {
1170	<	HashEntry<K,V> e;
1171	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1172	<	K k;
1173	<	if ((k = e.key) == key ||
1174	<	(e.hash == hash && key.equals(k))) {
1175	<	oldValue = e.value;
1176	<	e.value = value;
1177	<	break;
1165	>	/**
1166	>	* Removes all of the mappings from this map.
1167	>	*/
1168	>	public void clear() {
1169	>	long delta = 0L; // negative number of deletions
1170	>	int i = 0;
1171	>	Node<K,V>[] tab = table;
1172	>	while (tab != null && i < tab.length) {
1173	>	int fh;
1174	>	Node<K,V> f = tabAt(tab, i);
1175	>	if (f == null)
1176	>	++i;
1177	>	else if ((fh = f.hash) == MOVED) {
1178	>	tab = helpTransfer(tab, f);
1179	>	i = 0; // restart
1180	>	}
1181	>	else {
1182	>	synchronized (f) {
1183	>	if (tabAt(tab, i) == f) {
1184	>	Node<K,V> p = (fh >= 0 ? f :
1185	>	(f instanceof TreeBin) ?
1186	>	((TreeBin<K,V>)f).first : null);
1187	>	while (p != null) {
1188	>	--delta;
1189	>	p = p.next;
1190	>	}
1191	>	setTabAt(tab, i++, null);
1192		}
1193		}
591	–	} finally {
592	–	unlock();
1194		}
594	–	return oldValue;
1195		}
1196	+	if (delta != 0L)
1197	+	addCount(delta, -1);
1198	+	}
1199
1200	<	final void clear() {
1201	<	lock();
1202	<	try {
1203	<	HashEntry<K,V>[] tab = table;
1204	<	for (int i = 0; i < tab.length ; i++)
1205	<	setEntryAt(tab, i, null);
1206	<	++modCount;
1207	<	count = 0;
1208	<	} finally {
1209	<	unlock();
1210	<	}
1211	<	}
1200	>	/**
1201	>	* Returns a {@link Set} view of the keys contained in this map.
1202	>	* The set is backed by the map, so changes to the map are
1203	>	* reflected in the set, and vice-versa. The set supports element
1204	>	* removal, which removes the corresponding mapping from this map,
1205	>	* via the {@code Iterator.remove}, {@code Set.remove},
1206	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1207	>	* operations.  It does not support the {@code add} or
1208	>	* {@code addAll} operations.
1209	>	*
1210	>	* <p>The view's iterators and spliterators are
1211	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1212	>	*
1213	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1214	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1215	>	*
1216	>	* @return the set view
1217	>	*/
1218	>	public KeySetView<K,V> keySet() {
1219	>	KeySetView<K,V> ks;
1220	>	if ((ks = keySet) != null) return ks;
1221	>	return keySet = new KeySetView<K,V>(this, null);
1222	>	}
1223	>
1224	>	/**
1225	>	* Returns a {@link Collection} view of the values contained in this map.
1226	>	* The collection is backed by the map, so changes to the map are
1227	>	* reflected in the collection, and vice-versa.  The collection
1228	>	* supports element removal, which removes the corresponding
1229	>	* mapping from this map, via the {@code Iterator.remove},
1230	>	* {@code Collection.remove}, {@code removeAll},
1231	>	* {@code retainAll}, and {@code clear} operations.  It does not
1232	>	* support the {@code add} or {@code addAll} operations.
1233	>	*
1234	>	* <p>The view's iterators and spliterators are
1235	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1236	>	*
1237	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1238	>	* and {@link Spliterator#NONNULL}.
1239	>	*
1240	>	* @return the collection view
1241	>	*/
1242	>	public Collection<V> values() {
1243	>	ValuesView<K,V> vs;
1244	>	if ((vs = values) != null) return vs;
1245	>	return values = new ValuesView<K,V>(this);
1246		}
1247
1248	<	// Accessing segments
1248	>	/**
1249	>	* Returns a {@link Set} view of the mappings contained in this map.
1250	>	* The set is backed by the map, so changes to the map are
1251	>	* reflected in the set, and vice-versa.  The set supports element
1252	>	* removal, which removes the corresponding mapping from the map,
1253	>	* via the {@code Iterator.remove}, {@code Set.remove},
1254	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1255	>	* operations.
1256	>	*
1257	>	* <p>The view's iterators and spliterators are
1258	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1259	>	*
1260	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1261	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1262	>	*
1263	>	* @return the set view
1264	>	*/
1265	>	public Set<Map.Entry<K,V>> entrySet() {
1266	>	EntrySetView<K,V> es;
1267	>	if ((es = entrySet) != null) return es;
1268	>	return entrySet = new EntrySetView<K,V>(this);
1269	>	}
1270
1271		/**
1272	<	* Gets the jth element of given segment array (if nonnull) with
1273	<	* volatile element access semantics via Unsafe.
1272	>	* Returns the hash code value for this {@link Map}, i.e.,
1273	>	* the sum of, for each key-value pair in the map,
1274	>	* {@code key.hashCode() ^ value.hashCode()}.
1275	>	*
1276	>	* @return the hash code value for this map
1277		*/
1278	<	@SuppressWarnings("unchecked")
1279	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
1280	<	long u = (j << SSHIFT) + SBASE;
1281	<	return ss == null ? null :
1282	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
1278	>	public int hashCode() {
1279	>	int h = 0;
1280	>	Node<K,V>[] t;
1281	>	if ((t = table) != null) {
1282	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1283	>	for (Node<K,V> p; (p = it.advance()) != null; )
1284	>	h += p.key.hashCode() ^ p.val.hashCode();
1285	>	}
1286	>	return h;
1287		}
1288
1289		/**
1290	<	* Returns the segment for the given index, creating it and
1291	<	* recording in segment table (via CAS) if not already present.
1290	>	* Returns a string representation of this map.  The string
1291	>	* representation consists of a list of key-value mappings (in no
1292	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1293	>	* mappings are separated by the characters {@code ", "} (comma
1294	>	* and space).  Each key-value mapping is rendered as the key
1295	>	* followed by an equals sign ("{@code =}") followed by the
1296	>	* associated value.
1297		*
1298	<	* @param k the index
629	<	* @return the segment
1298	>	* @return a string representation of this map
1299		*/
1300	<	@SuppressWarnings("unchecked")
1301	<	private Segment<K,V> ensureSegment(int k) {
1302	<	final Segment<K,V>[] ss = this.segments;
1303	<	long u = (k << SSHIFT) + SBASE; // raw offset
1304	<	Segment<K,V> seg;
1305	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
1306	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
1307	<	int cap = proto.table.length;
1308	<	float lf = proto.loadFactor;
1309	<	int threshold = (int)(cap * lf);
1310	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry[cap];
1311	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1312	<	== null) { // recheck
1313	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
1314	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1315	<	== null) {
1316	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
648	<	break;
649	<	}
1300	>	public String toString() {
1301	>	Node<K,V>[] t;
1302	>	int f = (t = table) == null ? 0 : t.length;
1303	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1304	>	StringBuilder sb = new StringBuilder();
1305	>	sb.append('{');
1306	>	Node<K,V> p;
1307	>	if ((p = it.advance()) != null) {
1308	>	for (;;) {
1309	>	K k = p.key;
1310	>	V v = p.val;
1311	>	sb.append(k == this ? "(this Map)" : k);
1312	>	sb.append('=');
1313	>	sb.append(v == this ? "(this Map)" : v);
1314	>	if ((p = it.advance()) == null)
1315	>	break;
1316	>	sb.append(',').append(' ');
1317		}
1318		}
1319	<	return seg;
1319	>	return sb.append('}').toString();
1320		}
1321
655	–	// Hash-based segment and entry accesses
656	–
1322		/**
1323	<	* Get the segment for the given hash
1323	>	* Compares the specified object with this map for equality.
1324	>	* Returns {@code true} if the given object is a map with the same
1325	>	* mappings as this map.  This operation may return misleading
1326	>	* results if either map is concurrently modified during execution
1327	>	* of this method.
1328	>	*
1329	>	* @param o object to be compared for equality with this map
1330	>	* @return {@code true} if the specified object is equal to this map
1331		*/
1332	<	@SuppressWarnings("unchecked")
1333	<	private Segment<K,V> segmentForHash(int h) {
1334	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1335	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
1332	>	public boolean equals(Object o) {
1333	>	if (o != this) {
1334	>	if (!(o instanceof Map))
1335	>	return false;
1336	>	Map<?,?> m = (Map<?,?>) o;
1337	>	Node<K,V>[] t;
1338	>	int f = (t = table) == null ? 0 : t.length;
1339	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1340	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1341	>	V val = p.val;
1342	>	Object v = m.get(p.key);
1343	>	if (v == null || (v != val && !v.equals(val)))
1344	>	return false;
1345	>	}
1346	>	for (Map.Entry<?,?> e : m.entrySet()) {
1347	>	Object mk, mv, v;
1348	>	if ((mk = e.getKey()) == null ||
1349	>	(mv = e.getValue()) == null ||
1350	>	(v = get(mk)) == null ||
1351	>	(mv != v && !mv.equals(v)))
1352	>	return false;
1353	>	}
1354	>	}
1355	>	return true;
1356		}
1357
1358		/**
1359	<	* Gets the table entry for the given segment and hash
1359	>	* Stripped-down version of helper class used in previous version,
1360	>	* declared for the sake of serialization compatibility.
1361		*/
1362	<	@SuppressWarnings("unchecked")
1363	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
1364	<	HashEntry<K,V>[] tab;
1365	<	return seg == null || (tab = seg.table) == null? null :
673	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
674	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1362	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1363	>	private static final long serialVersionUID = 2249069246763182397L;
1364	>	final float loadFactor;
1365	>	Segment(float lf) { this.loadFactor = lf; }
1366		}
1367
677	–	/* ---------------- Public operations -------------- */
678	–
1368		/**
1369	<	* Creates a new, empty map with the specified initial
1370	<	* capacity, load factor and concurrency level.
1371	<	*
1372	<	* @param initialCapacity the initial capacity. The implementation
1373	<	* performs internal sizing to accommodate this many elements.
1374	<	* @param loadFactor  the load factor threshold, used to control resizing.
1375	<	* Resizing may be performed when the average number of elements per
1376	<	* bin exceeds this threshold.
688	<	* @param concurrencyLevel the estimated number of concurrently
689	<	* updating threads. The implementation performs internal sizing
690	<	* to try to accommodate this many threads.
691	<	* @throws IllegalArgumentException if the initial capacity is
692	<	* negative or the load factor or concurrencyLevel are
693	<	* nonpositive.
1369	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1370	>	* stream (i.e., serializes it).
1371	>	* @param s the stream
1372	>	* @throws java.io.IOException if an I/O error occurs
1373	>	* @serialData
1374	>	* the serialized fields, followed by the key (Object) and value
1375	>	* (Object) for each key-value mapping, followed by a null pair.
1376	>	* The key-value mappings are emitted in no particular order.
1377		*/
1378	<	@SuppressWarnings("unchecked")
1379	<	public ConcurrentHashMap(int initialCapacity,
1380	<	float loadFactor, int concurrencyLevel) {
1381	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
699	<	throw new IllegalArgumentException();
700	<	if (concurrencyLevel > MAX_SEGMENTS)
701	<	concurrencyLevel = MAX_SEGMENTS;
702	<	// Find power-of-two sizes best matching arguments
1378	>	private void writeObject(java.io.ObjectOutputStream s)
1379	>	throws java.io.IOException {
1380	>	// For serialization compatibility
1381	>	// Emulate segment calculation from previous version of this class
1382		int sshift = 0;
1383		int ssize = 1;
1384	<	while (ssize < concurrencyLevel) {
1384	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1385		++sshift;
1386		ssize <<= 1;
1387		}
1388	<	this.segmentShift = 32 - sshift;
1389	<	this.segmentMask = ssize - 1;
1390	<	if (initialCapacity > MAXIMUM_CAPACITY)
1391	<	initialCapacity = MAXIMUM_CAPACITY;
1392	<	int c = initialCapacity / ssize;
1393	<	if (c * ssize < initialCapacity)
1394	<	++c;
1395	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
1396	<	while (cap < c)
1397	<	cap <<= 1;
1398	<	// create segments and segments[0]
1399	<	Segment<K,V> s0 =
1400	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
1401	<	(HashEntry<K,V>[])new HashEntry[cap]);
1402	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment[ssize];
1403	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
1404	<	this.segments = ss;
1388	>	int segmentShift = 32 - sshift;
1389	>	int segmentMask = ssize - 1;
1390	>	@SuppressWarnings("unchecked")
1391	>	Segment<K,V>[] segments = (Segment<K,V>[])
1392	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1393	>	for (int i = 0; i < segments.length; ++i)
1394	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1395	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1396	>	streamFields.put("segments", segments);
1397	>	streamFields.put("segmentShift", segmentShift);
1398	>	streamFields.put("segmentMask", segmentMask);
1399	>	s.writeFields();
1400	>
1401	>	Node<K,V>[] t;
1402	>	if ((t = table) != null) {
1403	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1404	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1405	>	s.writeObject(p.key);
1406	>	s.writeObject(p.val);
1407	>	}
1408	>	}
1409	>	s.writeObject(null);
1410	>	s.writeObject(null);
1411		}
1412
1413		/**
1414	<	* Creates a new, empty map with the specified initial capacity
1415	<	* and load factor and with the default concurrencyLevel (16).
1416	<	*
1417	<	* @param initialCapacity The implementation performs internal
1418	<	* sizing to accommodate this many elements.
1419	<	* @param loadFactor  the load factor threshold, used to control resizing.
1420	<	* Resizing may be performed when the average number of elements per
1421	<	* bin exceeds this threshold.
1422	<	* @throws IllegalArgumentException if the initial capacity of
1423	<	* elements is negative or the load factor is nonpositive
1414	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1415	>	* @param s the stream
1416	>	* @throws ClassNotFoundException if the class of a serialized object
1417	>	*         could not be found
1418	>	* @throws java.io.IOException if an I/O error occurs
1419	>	*/
1420	>	private void readObject(java.io.ObjectInputStream s)
1421	>	throws java.io.IOException, ClassNotFoundException {
1422	>	/*
1423	>	* To improve performance in typical cases, we create nodes
1424	>	* while reading, then place in table once size is known.
1425	>	* However, we must also validate uniqueness and deal with
1426	>	* overpopulated bins while doing so, which requires
1427	>	* specialized versions of putVal mechanics.
1428	>	*/
1429	>	sizeCtl = -1; // force exclusion for table construction
1430	>	s.defaultReadObject();
1431	>	long size = 0L;
1432	>	Node<K,V> p = null;
1433	>	for (;;) {
1434	>	@SuppressWarnings("unchecked")
1435	>	K k = (K) s.readObject();
1436	>	@SuppressWarnings("unchecked")
1437	>	V v = (V) s.readObject();
1438	>	if (k != null && v != null) {
1439	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1440	>	++size;
1441	>	}
1442	>	else
1443	>	break;
1444	>	}
1445	>	if (size == 0L)
1446	>	sizeCtl = 0;
1447	>	else {
1448	>	int n;
1449	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1450	>	n = MAXIMUM_CAPACITY;
1451	>	else {
1452	>	int sz = (int)size;
1453	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1454	>	}
1455	>	@SuppressWarnings("unchecked")
1456	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1457	>	int mask = n - 1;
1458	>	long added = 0L;
1459	>	while (p != null) {
1460	>	boolean insertAtFront;
1461	>	Node<K,V> next = p.next, first;
1462	>	int h = p.hash, j = h & mask;
1463	>	if ((first = tabAt(tab, j)) == null)
1464	>	insertAtFront = true;
1465	>	else {
1466	>	K k = p.key;
1467	>	if (first.hash < 0) {
1468	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1469	>	if (t.putTreeVal(h, k, p.val) == null)
1470	>	++added;
1471	>	insertAtFront = false;
1472	>	}
1473	>	else {
1474	>	int binCount = 0;
1475	>	insertAtFront = true;
1476	>	Node<K,V> q; K qk;
1477	>	for (q = first; q != null; q = q.next) {
1478	>	if (q.hash == h &&
1479	>	((qk = q.key) == k ||
1480	>	(qk != null && k.equals(qk)))) {
1481	>	insertAtFront = false;
1482	>	break;
1483	>	}
1484	>	++binCount;
1485	>	}
1486	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1487	>	insertAtFront = false;
1488	>	++added;
1489	>	p.next = first;
1490	>	TreeNode<K,V> hd = null, tl = null;
1491	>	for (q = p; q != null; q = q.next) {
1492	>	TreeNode<K,V> t = new TreeNode<K,V>
1493	>	(q.hash, q.key, q.val, null, null);
1494	>	if ((t.prev = tl) == null)
1495	>	hd = t;
1496	>	else
1497	>	tl.next = t;
1498	>	tl = t;
1499	>	}
1500	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1501	>	}
1502	>	}
1503	>	}
1504	>	if (insertAtFront) {
1505	>	++added;
1506	>	p.next = first;
1507	>	setTabAt(tab, j, p);
1508	>	}
1509	>	p = next;
1510	>	}
1511	>	table = tab;
1512	>	sizeCtl = n - (n >>> 2);
1513	>	baseCount = added;
1514	>	}
1515	>	}
1516	>
1517	>	// ConcurrentMap methods
1518	>
1519	>	/**
1520	>	* {@inheritDoc}
1521		*
1522	<	* @since 1.6
1522	>	* @return the previous value associated with the specified key,
1523	>	*         or {@code null} if there was no mapping for the key
1524	>	* @throws NullPointerException if the specified key or value is null
1525		*/
1526	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
1527	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1526	>	public V putIfAbsent(K key, V value) {
1527	>	return putVal(key, value, true);
1528		}
1529
1530		/**
1531	<	* Creates a new, empty map with the specified initial capacity,
748	<	* and with default load factor (0.75) and concurrencyLevel (16).
1531	>	* {@inheritDoc}
1532		*
1533	<	* @param initialCapacity the initial capacity. The implementation
751	<	* performs internal sizing to accommodate this many elements.
752	<	* @throws IllegalArgumentException if the initial capacity of
753	<	* elements is negative.
1533	>	* @throws NullPointerException if the specified key is null
1534		*/
1535	<	public ConcurrentHashMap(int initialCapacity) {
1536	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1535	>	public boolean remove(Object key, Object value) {
1536	>	if (key == null)
1537	>	throw new NullPointerException();
1538	>	return value != null && replaceNode(key, null, value) != null;
1539		}
1540
1541		/**
1542	<	* Creates a new, empty map with a default initial capacity (16),
1543	<	* load factor (0.75) and concurrencyLevel (16).
1542	>	* {@inheritDoc}
1543	>	*
1544	>	* @throws NullPointerException if any of the arguments are null
1545		*/
1546	<	public ConcurrentHashMap() {
1547	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1546	>	public boolean replace(K key, V oldValue, V newValue) {
1547	>	if (key == null || oldValue == null || newValue == null)
1548	>	throw new NullPointerException();
1549	>	return replaceNode(key, newValue, oldValue) != null;
1550		}
1551
1552		/**
1553	<	* Creates a new map with the same mappings as the given map.
769	<	* The map is created with a capacity of 1.5 times the number
770	<	* of mappings in the given map or 16 (whichever is greater),
771	<	* and a default load factor (0.75) and concurrencyLevel (16).
1553	>	* {@inheritDoc}
1554		*
1555	<	* @param m the map
1555	>	* @return the previous value associated with the specified key,
1556	>	*         or {@code null} if there was no mapping for the key
1557	>	* @throws NullPointerException if the specified key or value is null
1558		*/
1559	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
1560	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
1561	<	DEFAULT_INITIAL_CAPACITY),
1562	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
779	<	putAll(m);
1559	>	public V replace(K key, V value) {
1560	>	if (key == null || value == null)
1561	>	throw new NullPointerException();
1562	>	return replaceNode(key, value, null);
1563		}
1564
1565	+	// Overrides of JDK8+ Map extension method defaults
1566	+
1567		/**
1568	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
1568	>	* Returns the value to which the specified key is mapped, or the
1569	>	* given default value if this map contains no mapping for the
1570	>	* key.
1571		*
1572	<	* @return <tt>true</tt> if this map contains no key-value mappings
1572	>	* @param key the key whose associated value is to be returned
1573	>	* @param defaultValue the value to return if this map contains
1574	>	* no mapping for the given key
1575	>	* @return the mapping for the key, if present; else the default value
1576	>	* @throws NullPointerException if the specified key is null
1577		*/
1578	<	public boolean isEmpty() {
1579	<	/*
1580	<	* Sum per-segment modCounts to avoid mis-reporting when
1581	<	* elements are concurrently added and removed in one segment
1582	<	* while checking another, in which case the table was never
1583	<	* actually empty at any point. (The sum ensures accuracy up
1584	<	* through at least 1<<31 per-segment modifications before
1585	<	* recheck.)  Methods size() and containsValue() use similar
1586	<	* constructions for stability checks.
1587	<	*/
1588	<	long sum = 0L;
1589	<	final Segment<K,V>[] segments = this.segments;
799	<	for (int j = 0; j < segments.length; ++j) {
800	<	Segment<K,V> seg = segmentAt(segments, j);
801	<	if (seg != null) {
802	<	if (seg.count != 0)
803	<	return false;
804	<	sum += seg.modCount;
1578	>	public V getOrDefault(Object key, V defaultValue) {
1579	>	V v;
1580	>	return (v = get(key)) == null ? defaultValue : v;
1581	>	}
1582	>
1583	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1584	>	if (action == null) throw new NullPointerException();
1585	>	Node<K,V>[] t;
1586	>	if ((t = table) != null) {
1587	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1588	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1589	>	action.accept(p.key, p.val);
1590		}
1591		}
1592	<	if (sum != 0L) { // recheck unless no modifications
1593	<	for (int j = 0; j < segments.length; ++j) {
1594	<	Segment<K,V> seg = segmentAt(segments, j);
1595	<	if (seg != null) {
1596	<	if (seg.count != 0)
1597	<	return false;
1598	<	sum -= seg.modCount;
1592	>	}
1593	>
1594	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1595	>	if (function == null) throw new NullPointerException();
1596	>	Node<K,V>[] t;
1597	>	if ((t = table) != null) {
1598	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1599	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1600	>	V oldValue = p.val;
1601	>	for (K key = p.key;;) {
1602	>	V newValue = function.apply(key, oldValue);
1603	>	if (newValue == null)
1604	>	throw new NullPointerException();
1605	>	if (replaceNode(key, newValue, oldValue) != null ||
1606	>	(oldValue = get(key)) == null)
1607	>	break;
1608		}
1609		}
816	–	if (sum != 0L)
817	–	return false;
1610		}
819	–	return true;
1611		}
1612
1613		/**
1614	<	* Returns the number of key-value mappings in this map.  If the
1615	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
1616	<	* <tt>Integer.MAX_VALUE</tt>.
1614	>	* Helper method for EntrySetView.removeIf.
1615	>	*/
1616	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1617	>	if (function == null) throw new NullPointerException();
1618	>	Node<K,V>[] t;
1619	>	boolean removed = false;
1620	>	if ((t = table) != null) {
1621	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1622	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1623	>	K k = p.key;
1624	>	V v = p.val;
1625	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1626	>	if (function.test(e) && replaceNode(k, null, v) != null)
1627	>	removed = true;
1628	>	}
1629	>	}
1630	>	return removed;
1631	>	}
1632	>
1633	>	/**
1634	>	* Helper method for ValuesView.removeIf.
1635	>	*/
1636	>	boolean removeValueIf(Predicate<? super V> function) {
1637	>	if (function == null) throw new NullPointerException();
1638	>	Node<K,V>[] t;
1639	>	boolean removed = false;
1640	>	if ((t = table) != null) {
1641	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1642	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1643	>	K k = p.key;
1644	>	V v = p.val;
1645	>	if (function.test(v) && replaceNode(k, null, v) != null)
1646	>	removed = true;
1647	>	}
1648	>	}
1649	>	return removed;
1650	>	}
1651	>
1652	>	/**
1653	>	* If the specified key is not already associated with a value,
1654	>	* attempts to compute its value using the given mapping function
1655	>	* and enters it into this map unless {@code null}.  The entire
1656	>	* method invocation is performed atomically, so the function is
1657	>	* applied at most once per key.  Some attempted update operations
1658	>	* on this map by other threads may be blocked while computation
1659	>	* is in progress, so the computation should be short and simple,
1660	>	* and must not attempt to update any other mappings of this map.
1661		*
1662	<	* @return the number of key-value mappings in this map
1662	>	* @param key key with which the specified value is to be associated
1663	>	* @param mappingFunction the function to compute a value
1664	>	* @return the current (existing or computed) value associated with
1665	>	*         the specified key, or null if the computed value is null
1666	>	* @throws NullPointerException if the specified key or mappingFunction
1667	>	*         is null
1668	>	* @throws IllegalStateException if the computation detectably
1669	>	*         attempts a recursive update to this map that would
1670	>	*         otherwise never complete
1671	>	* @throws RuntimeException or Error if the mappingFunction does so,
1672	>	*         in which case the mapping is left unestablished
1673		*/
1674	<	public int size() {
1675	<	// Try a few times to get accurate count. On failure due to
1676	<	// continuous async changes in table, resort to locking.
1677	<	final Segment<K,V>[] segments = this.segments;
1678	<	int size;
1679	<	boolean overflow; // true if size overflows 32 bits
1680	<	long sum;         // sum of modCounts
1681	<	long last = 0L;   // previous sum
1682	<	int retries = -1; // first iteration isn't retry
1683	<	try {
1684	<	for (;;) {
1685	<	if (retries++ == RETRIES_BEFORE_LOCK) {
1686	<	for (int j = 0; j < segments.length; ++j)
1687	<	ensureSegment(j).lock(); // force creation
1688	<	}
1689	<	sum = 0L;
1690	<	size = 0;
1691	<	overflow = false;
1692	<	for (int j = 0; j < segments.length; ++j) {
1693	<	Segment<K,V> seg = segmentAt(segments, j);
1694	<	if (seg != null) {
1695	<	sum += seg.modCount;
851	<	int c = seg.count;
852	<	if (c < 0 || (size += c) < 0)
853	<	overflow = true;
1674	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1675	>	if (key == null || mappingFunction == null)
1676	>	throw new NullPointerException();
1677	>	int h = spread(key.hashCode());
1678	>	V val = null;
1679	>	int binCount = 0;
1680	>	for (Node<K,V>[] tab = table;;) {
1681	>	Node<K,V> f; int n, i, fh; K fk; V fv;
1682	>	if (tab == null || (n = tab.length) == 0)
1683	>	tab = initTable();
1684	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1685	>	Node<K,V> r = new ReservationNode<K,V>();
1686	>	synchronized (r) {
1687	>	if (casTabAt(tab, i, null, r)) {
1688	>	binCount = 1;
1689	>	Node<K,V> node = null;
1690	>	try {
1691	>	if ((val = mappingFunction.apply(key)) != null)
1692	>	node = new Node<K,V>(h, key, val);
1693	>	} finally {
1694	>	setTabAt(tab, i, node);
1695	>	}
1696		}
1697		}
1698	<	if (sum == last)
1698	>	if (binCount != 0)
1699		break;
858	–	last = sum;
1700		}
1701	<	} finally {
1702	<	if (retries > RETRIES_BEFORE_LOCK) {
1703	<	for (int j = 0; j < segments.length; ++j)
1704	<	segmentAt(segments, j).unlock();
1701	>	else if ((fh = f.hash) == MOVED)
1702	>	tab = helpTransfer(tab, f);
1703	>	else if (fh == h    // check first node without acquiring lock
1704	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
1705	>	&& (fv = f.val) != null)
1706	>	return fv;
1707	>	else {
1708	>	boolean added = false;
1709	>	synchronized (f) {
1710	>	if (tabAt(tab, i) == f) {
1711	>	if (fh >= 0) {
1712	>	binCount = 1;
1713	>	for (Node<K,V> e = f;; ++binCount) {
1714	>	K ek;
1715	>	if (e.hash == h &&
1716	>	((ek = e.key) == key ||
1717	>	(ek != null && key.equals(ek)))) {
1718	>	val = e.val;
1719	>	break;
1720	>	}
1721	>	Node<K,V> pred = e;
1722	>	if ((e = e.next) == null) {
1723	>	if ((val = mappingFunction.apply(key)) != null) {
1724	>	if (pred.next != null)
1725	>	throw new IllegalStateException("Recursive update");
1726	>	added = true;
1727	>	pred.next = new Node<K,V>(h, key, val);
1728	>	}
1729	>	break;
1730	>	}
1731	>	}
1732	>	}
1733	>	else if (f instanceof TreeBin) {
1734	>	binCount = 2;
1735	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1736	>	TreeNode<K,V> r, p;
1737	>	if ((r = t.root) != null &&
1738	>	(p = r.findTreeNode(h, key, null)) != null)
1739	>	val = p.val;
1740	>	else if ((val = mappingFunction.apply(key)) != null) {
1741	>	added = true;
1742	>	t.putTreeVal(h, key, val);
1743	>	}
1744	>	}
1745	>	else if (f instanceof ReservationNode)
1746	>	throw new IllegalStateException("Recursive update");
1747	>	}
1748	>	}
1749	>	if (binCount != 0) {
1750	>	if (binCount >= TREEIFY_THRESHOLD)
1751	>	treeifyBin(tab, i);
1752	>	if (!added)
1753	>	return val;
1754	>	break;
1755	>	}
1756		}
1757		}
1758	<	return overflow ? Integer.MAX_VALUE : size;
1758	>	if (val != null)
1759	>	addCount(1L, binCount);
1760	>	return val;
1761		}
1762
1763		/**
1764	<	* Returns the value to which the specified key is mapped,
1765	<	* or {@code null} if this map contains no mapping for the key.
1766	<	*
1767	<	* <p>More formally, if this map contains a mapping from a key
1768	<	* {@code k} to a value {@code v} such that {@code key.equals(k)},
1769	<	* then this method returns {@code v}; otherwise it returns
1770	<	* {@code null}.  (There can be at most one such mapping.)
1764	>	* If the value for the specified key is present, attempts to
1765	>	* compute a new mapping given the key and its current mapped
1766	>	* value.  The entire method invocation is performed atomically.
1767	>	* Some attempted update operations on this map by other threads
1768	>	* may be blocked while computation is in progress, so the
1769	>	* computation should be short and simple, and must not attempt to
1770	>	* update any other mappings of this map.
1771		*
1772	<	* @throws NullPointerException if the specified key is null
1772	>	* @param key key with which a value may be associated
1773	>	* @param remappingFunction the function to compute a value
1774	>	* @return the new value associated with the specified key, or null if none
1775	>	* @throws NullPointerException if the specified key or remappingFunction
1776	>	*         is null
1777	>	* @throws IllegalStateException if the computation detectably
1778	>	*         attempts a recursive update to this map that would
1779	>	*         otherwise never complete
1780	>	* @throws RuntimeException or Error if the remappingFunction does so,
1781	>	*         in which case the mapping is unchanged
1782		*/
1783	<	public V get(Object key) {
1784	<	int hash = hash(key.hashCode());
1785	<	for (HashEntry<K,V> e = entryForHash(segmentForHash(hash), hash);
1786	<	e != null; e = e.next) {
1787	<	K k;
1788	<	if ((k = e.key) == key || (e.hash == hash && key.equals(k)))
1789	<	return e.value;
1783	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1784	>	if (key == null || remappingFunction == null)
1785	>	throw new NullPointerException();
1786	>	int h = spread(key.hashCode());
1787	>	V val = null;
1788	>	int delta = 0;
1789	>	int binCount = 0;
1790	>	for (Node<K,V>[] tab = table;;) {
1791	>	Node<K,V> f; int n, i, fh;
1792	>	if (tab == null || (n = tab.length) == 0)
1793	>	tab = initTable();
1794	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1795	>	break;
1796	>	else if ((fh = f.hash) == MOVED)
1797	>	tab = helpTransfer(tab, f);
1798	>	else {
1799	>	synchronized (f) {
1800	>	if (tabAt(tab, i) == f) {
1801	>	if (fh >= 0) {
1802	>	binCount = 1;
1803	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1804	>	K ek;
1805	>	if (e.hash == h &&
1806	>	((ek = e.key) == key ||
1807	>	(ek != null && key.equals(ek)))) {
1808	>	val = remappingFunction.apply(key, e.val);
1809	>	if (val != null)
1810	>	e.val = val;
1811	>	else {
1812	>	delta = -1;
1813	>	Node<K,V> en = e.next;
1814	>	if (pred != null)
1815	>	pred.next = en;
1816	>	else
1817	>	setTabAt(tab, i, en);
1818	>	}
1819	>	break;
1820	>	}
1821	>	pred = e;
1822	>	if ((e = e.next) == null)
1823	>	break;
1824	>	}
1825	>	}
1826	>	else if (f instanceof TreeBin) {
1827	>	binCount = 2;
1828	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1829	>	TreeNode<K,V> r, p;
1830	>	if ((r = t.root) != null &&
1831	>	(p = r.findTreeNode(h, key, null)) != null) {
1832	>	val = remappingFunction.apply(key, p.val);
1833	>	if (val != null)
1834	>	p.val = val;
1835	>	else {
1836	>	delta = -1;
1837	>	if (t.removeTreeNode(p))
1838	>	setTabAt(tab, i, untreeify(t.first));
1839	>	}
1840	>	}
1841	>	}
1842	>	else if (f instanceof ReservationNode)
1843	>	throw new IllegalStateException("Recursive update");
1844	>	}
1845	>	}
1846	>	if (binCount != 0)
1847	>	break;
1848	>	}
1849		}
1850	<	return null;
1850	>	if (delta != 0)
1851	>	addCount((long)delta, binCount);
1852	>	return val;
1853		}
1854
1855		/**
1856	<	* Tests if the specified object is a key in this table.
1856	>	* Attempts to compute a mapping for the specified key and its
1857	>	* current mapped value (or {@code null} if there is no current
1858	>	* mapping). The entire method invocation is performed atomically.
1859	>	* Some attempted update operations on this map by other threads
1860	>	* may be blocked while computation is in progress, so the
1861	>	* computation should be short and simple, and must not attempt to
1862	>	* update any other mappings of this Map.
1863		*
1864	<	* @param  key   possible key
1865	<	* @return <tt>true</tt> if and only if the specified object
1866	<	*         is a key in this table, as determined by the
1867	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
1868	<	* @throws NullPointerException if the specified key is null
1869	<	*/
1870	<	public boolean containsKey(Object key) {
1871	<	int hash = hash(key.hashCode());
1872	<	for (HashEntry<K,V> e = entryForHash(segmentForHash(hash), hash);
1873	<	e != null; e = e.next) {
1874	<	K k;
1875	<	if ((k = e.key) == key || (e.hash == hash && key.equals(k)))
1876	<	return true;
1864	>	* @param key key with which the specified value is to be associated
1865	>	* @param remappingFunction the function to compute a value
1866	>	* @return the new value associated with the specified key, or null if none
1867	>	* @throws NullPointerException if the specified key or remappingFunction
1868	>	*         is null
1869	>	* @throws IllegalStateException if the computation detectably
1870	>	*         attempts a recursive update to this map that would
1871	>	*         otherwise never complete
1872	>	* @throws RuntimeException or Error if the remappingFunction does so,
1873	>	*         in which case the mapping is unchanged
1874	>	*/
1875	>	public V compute(K key,
1876	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1877	>	if (key == null || remappingFunction == null)
1878	>	throw new NullPointerException();
1879	>	int h = spread(key.hashCode());
1880	>	V val = null;
1881	>	int delta = 0;
1882	>	int binCount = 0;
1883	>	for (Node<K,V>[] tab = table;;) {
1884	>	Node<K,V> f; int n, i, fh;
1885	>	if (tab == null || (n = tab.length) == 0)
1886	>	tab = initTable();
1887	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1888	>	Node<K,V> r = new ReservationNode<K,V>();
1889	>	synchronized (r) {
1890	>	if (casTabAt(tab, i, null, r)) {
1891	>	binCount = 1;
1892	>	Node<K,V> node = null;
1893	>	try {
1894	>	if ((val = remappingFunction.apply(key, null)) != null) {
1895	>	delta = 1;
1896	>	node = new Node<K,V>(h, key, val);
1897	>	}
1898	>	} finally {
1899	>	setTabAt(tab, i, node);
1900	>	}
1901	>	}
1902	>	}
1903	>	if (binCount != 0)
1904	>	break;
1905	>	}
1906	>	else if ((fh = f.hash) == MOVED)
1907	>	tab = helpTransfer(tab, f);
1908	>	else {
1909	>	synchronized (f) {
1910	>	if (tabAt(tab, i) == f) {
1911	>	if (fh >= 0) {
1912	>	binCount = 1;
1913	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1914	>	K ek;
1915	>	if (e.hash == h &&
1916	>	((ek = e.key) == key ||
1917	>	(ek != null && key.equals(ek)))) {
1918	>	val = remappingFunction.apply(key, e.val);
1919	>	if (val != null)
1920	>	e.val = val;
1921	>	else {
1922	>	delta = -1;
1923	>	Node<K,V> en = e.next;
1924	>	if (pred != null)
1925	>	pred.next = en;
1926	>	else
1927	>	setTabAt(tab, i, en);
1928	>	}
1929	>	break;
1930	>	}
1931	>	pred = e;
1932	>	if ((e = e.next) == null) {
1933	>	val = remappingFunction.apply(key, null);
1934	>	if (val != null) {
1935	>	if (pred.next != null)
1936	>	throw new IllegalStateException("Recursive update");
1937	>	delta = 1;
1938	>	pred.next = new Node<K,V>(h, key, val);
1939	>	}
1940	>	break;
1941	>	}
1942	>	}
1943	>	}
1944	>	else if (f instanceof TreeBin) {
1945	>	binCount = 1;
1946	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1947	>	TreeNode<K,V> r, p;
1948	>	if ((r = t.root) != null)
1949	>	p = r.findTreeNode(h, key, null);
1950	>	else
1951	>	p = null;
1952	>	V pv = (p == null) ? null : p.val;
1953	>	val = remappingFunction.apply(key, pv);
1954	>	if (val != null) {
1955	>	if (p != null)
1956	>	p.val = val;
1957	>	else {
1958	>	delta = 1;
1959	>	t.putTreeVal(h, key, val);
1960	>	}
1961	>	}
1962	>	else if (p != null) {
1963	>	delta = -1;
1964	>	if (t.removeTreeNode(p))
1965	>	setTabAt(tab, i, untreeify(t.first));
1966	>	}
1967	>	}
1968	>	else if (f instanceof ReservationNode)
1969	>	throw new IllegalStateException("Recursive update");
1970	>	}
1971	>	}
1972	>	if (binCount != 0) {
1973	>	if (binCount >= TREEIFY_THRESHOLD)
1974	>	treeifyBin(tab, i);
1975	>	break;
1976	>	}
1977	>	}
1978		}
1979	<	return false;
1979	>	if (delta != 0)
1980	>	addCount((long)delta, binCount);
1981	>	return val;
1982		}
1983
1984		/**
1985	<	* Returns <tt>true</tt> if this map maps one or more keys to the
1986	<	* specified value. Note: This method requires a full internal
1987	<	* traversal of the hash table, and so is much slower than
1988	<	* method <tt>containsKey</tt>.
1985	>	* If the specified key is not already associated with a
1986	>	* (non-null) value, associates it with the given value.
1987	>	* Otherwise, replaces the value with the results of the given
1988	>	* remapping function, or removes if {@code null}. The entire
1989	>	* method invocation is performed atomically.  Some attempted
1990	>	* update operations on this map by other threads may be blocked
1991	>	* while computation is in progress, so the computation should be
1992	>	* short and simple, and must not attempt to update any other
1993	>	* mappings of this Map.
1994		*
1995	<	* @param value value whose presence in this map is to be tested
1996	<	* @return <tt>true</tt> if this map maps one or more keys to the
1997	<	*         specified value
1998	<	* @throws NullPointerException if the specified value is null
1995	>	* @param key key with which the specified value is to be associated
1996	>	* @param value the value to use if absent
1997	>	* @param remappingFunction the function to recompute a value if present
1998	>	* @return the new value associated with the specified key, or null if none
1999	>	* @throws NullPointerException if the specified key or the
2000	>	*         remappingFunction is null
2001	>	* @throws RuntimeException or Error if the remappingFunction does so,
2002	>	*         in which case the mapping is unchanged
2003		*/
2004	<	public boolean containsValue(Object value) {
2005	<	// Same idea as size() but using hashes as checksum
924	<	if (value == null)
2004	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2005	>	if (key == null || value == null || remappingFunction == null)
2006		throw new NullPointerException();
2007	<	final Segment<K,V>[] segments = this.segments;
2008	<	boolean found = false;
2009	<	long last = 0L;
2010	<	int retries = -1;
2011	<	try {
2012	<	outer: for (;;) {
2013	<	if (retries++ == RETRIES_BEFORE_LOCK) {
2014	<	for (int j = 0; j < segments.length; ++j)
2015	<	ensureSegment(j).lock(); // force creation
2016	<	}
2017	<	long sum = 0L;
2018	<	for (int j = 0; j < segments.length; ++j) {
2019	<	HashEntry<K,V>[] tab;
2020	<	Segment<K,V> seg = segmentAt(segments, j);
2021	<	if (seg != null && (tab = seg.table) != null) {
2022	<	for (int i = 0 ; i < tab.length; i++) {
2023	<	HashEntry<K,V> e;
2024	<	for (e = entryAt(tab, i); e != null; e = e.next) {
2025	<	V v = e.value;
2026	<	if (v != null && value.equals(v)) {
2027	<	found = true;
2028	<	break outer;
2007	>	int h = spread(key.hashCode());
2008	>	V val = null;
2009	>	int delta = 0;
2010	>	int binCount = 0;
2011	>	for (Node<K,V>[] tab = table;;) {
2012	>	Node<K,V> f; int n, i, fh;
2013	>	if (tab == null || (n = tab.length) == 0)
2014	>	tab = initTable();
2015	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
2016	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value))) {
2017	>	delta = 1;
2018	>	val = value;
2019	>	break;
2020	>	}
2021	>	}
2022	>	else if ((fh = f.hash) == MOVED)
2023	>	tab = helpTransfer(tab, f);
2024	>	else {
2025	>	synchronized (f) {
2026	>	if (tabAt(tab, i) == f) {
2027	>	if (fh >= 0) {
2028	>	binCount = 1;
2029	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2030	>	K ek;
2031	>	if (e.hash == h &&
2032	>	((ek = e.key) == key ||
2033	>	(ek != null && key.equals(ek)))) {
2034	>	val = remappingFunction.apply(e.val, value);
2035	>	if (val != null)
2036	>	e.val = val;
2037	>	else {
2038	>	delta = -1;
2039	>	Node<K,V> en = e.next;
2040	>	if (pred != null)
2041	>	pred.next = en;
2042	>	else
2043	>	setTabAt(tab, i, en);
2044	>	}
2045	>	break;
2046	>	}
2047	>	pred = e;
2048	>	if ((e = e.next) == null) {
2049	>	delta = 1;
2050	>	val = value;
2051	>	pred.next = new Node<K,V>(h, key, val);
2052	>	break;
2053		}
949	–	sum += e.hash;
2054		}
2055		}
2056	+	else if (f instanceof TreeBin) {
2057	+	binCount = 2;
2058	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
2059	+	TreeNode<K,V> r = t.root;
2060	+	TreeNode<K,V> p = (r == null) ? null :
2061	+	r.findTreeNode(h, key, null);
2062	+	val = (p == null) ? value :
2063	+	remappingFunction.apply(p.val, value);
2064	+	if (val != null) {
2065	+	if (p != null)
2066	+	p.val = val;
2067	+	else {
2068	+	delta = 1;
2069	+	t.putTreeVal(h, key, val);
2070	+	}
2071	+	}
2072	+	else if (p != null) {
2073	+	delta = -1;
2074	+	if (t.removeTreeNode(p))
2075	+	setTabAt(tab, i, untreeify(t.first));
2076	+	}
2077	+	}
2078	+	else if (f instanceof ReservationNode)
2079	+	throw new IllegalStateException("Recursive update");
2080		}
2081		}
2082	<	if (sum == last)
2082	>	if (binCount != 0) {
2083	>	if (binCount >= TREEIFY_THRESHOLD)
2084	>	treeifyBin(tab, i);
2085		break;
2086	<	last = sum;
957	<	}
958	<	} finally {
959	<	if (retries > RETRIES_BEFORE_LOCK) {
960	<	for (int j = 0; j < segments.length; ++j)
961	<	segmentAt(segments, j).unlock();
2086	>	}
2087		}
2088		}
2089	<	return found;
2089	>	if (delta != 0)
2090	>	addCount((long)delta, binCount);
2091	>	return val;
2092		}
2093
2094	+	// Hashtable legacy methods
2095	+
2096		/**
2097	<	* Legacy method testing if some key maps into the specified value
2098	<	* in this table.  This method is identical in functionality to
2099	<	* {@link #containsValue}, and exists solely to ensure
2097	>	* Tests if some key maps into the specified value in this table.
2098	>	*
2099	>	* <p>Note that this method is identical in functionality to
2100	>	* {@link #containsValue(Object)}, and exists solely to ensure
2101		* full compatibility with class {@link java.util.Hashtable},
2102		* which supported this method prior to introduction of the
2103	<	* Java Collections framework.
2104	<
2103	>	* Java Collections Framework.
2104	>	*
2105		* @param  value a value to search for
2106	<	* @return <tt>true</tt> if and only if some key maps to the
2107	<	*         <tt>value</tt> argument in this table as
2108	<	*         determined by the <tt>equals</tt> method;
2109	<	*         <tt>false</tt> otherwise
2106	>	* @return {@code true} if and only if some key maps to the
2107	>	*         {@code value} argument in this table as
2108	>	*         determined by the {@code equals} method;
2109	>	*         {@code false} otherwise
2110		* @throws NullPointerException if the specified value is null
2111		*/
2112		public boolean contains(Object value) {
#	Line 984 | Line 2114 | public class ConcurrentHashMap<K, V> ext
2114		}
2115
2116		/**
2117	<	* Maps the specified key to the specified value in this table.
988	<	* Neither the key nor the value can be null.
989	<	*
990	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
991	<	* with a key that is equal to the original key.
2117	>	* Returns an enumeration of the keys in this table.
2118		*
2119	<	* @param key key with which the specified value is to be associated
2120	<	* @param value value to be associated with the specified key
995	<	* @return the previous value associated with <tt>key</tt>, or
996	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
997	<	* @throws NullPointerException if the specified key or value is null
2119	>	* @return an enumeration of the keys in this table
2120	>	* @see #keySet()
2121		*/
2122	<	public V put(K key, V value) {
2123	<	Segment<K,V> s;
2124	<	if (value == null)
2125	<	throw new NullPointerException();
1003	<	int hash = hash(key.hashCode());
1004	<	int j = (hash >>> segmentShift) & segmentMask;
1005	<	return ((s = segmentAt(segments, j)) == null? ensureSegment(j) : s).
1006	<	put(key, hash, value, false);
2122	>	public Enumeration<K> keys() {
2123	>	Node<K,V>[] t;
2124	>	int f = (t = table) == null ? 0 : t.length;
2125	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2126		}
2127
2128		/**
2129	<	* {@inheritDoc}
2129	>	* Returns an enumeration of the values in this table.
2130		*
2131	<	* @return the previous value associated with the specified key,
2132	<	*         or <tt>null</tt> if there was no mapping for the key
1014	<	* @throws NullPointerException if the specified key or value is null
2131	>	* @return an enumeration of the values in this table
2132	>	* @see #values()
2133		*/
2134	<	public V putIfAbsent(K key, V value) {
2135	<	Segment<K,V> s;
2136	<	if (value == null)
2137	<	throw new NullPointerException();
1020	<	int hash = hash(key.hashCode());
1021	<	int j = (hash >>> segmentShift) & segmentMask;
1022	<	return ((s = segmentAt(segments, j)) == null? ensureSegment(j) : s).
1023	<	put(key, hash, value, true);
2134	>	public Enumeration<V> elements() {
2135	>	Node<K,V>[] t;
2136	>	int f = (t = table) == null ? 0 : t.length;
2137	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2138		}
2139
2140	+	// ConcurrentHashMap-only methods
2141	+
2142		/**
2143	<	* Copies all of the mappings from the specified map to this one.
2144	<	* These mappings replace any mappings that this map had for any of the
2145	<	* keys currently in the specified map.
2143	>	* Returns the number of mappings. This method should be used
2144	>	* instead of {@link #size} because a ConcurrentHashMap may
2145	>	* contain more mappings than can be represented as an int. The
2146	>	* value returned is an estimate; the actual count may differ if
2147	>	* there are concurrent insertions or removals.
2148		*
2149	<	* @param m mappings to be stored in this map
2149	>	* @return the number of mappings
2150	>	* @since 1.8
2151		*/
2152	<	public void putAll(Map<? extends K, ? extends V> m) {
2153	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2154	<	put(e.getKey(), e.getValue());
2152	>	public long mappingCount() {
2153	>	long n = sumCount();
2154	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2155		}
2156
2157		/**
2158	<	* Removes the key (and its corresponding value) from this map.
2159	<	* This method does nothing if the key is not in the map.
2158	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2159	>	* from the given type to {@code Boolean.TRUE}.
2160		*
2161	<	* @param  key the key that needs to be removed
2162	<	* @return the previous value associated with <tt>key</tt>, or
2163	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
1045	<	* @throws NullPointerException if the specified key is null
2161	>	* @param <K> the element type of the returned set
2162	>	* @return the new set
2163	>	* @since 1.8
2164		*/
2165	<	public V remove(Object key) {
2166	<	int hash = hash(key.hashCode());
2167	<	Segment<K,V> s = segmentForHash(hash);
1050	<	return s == null ? null : s.remove(key, hash, null);
2165	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2166	>	return new KeySetView<K,Boolean>
2167	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2168		}
2169
2170		/**
2171	<	* {@inheritDoc}
2171	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2172	>	* from the given type to {@code Boolean.TRUE}.
2173		*
2174	<	* @throws NullPointerException if the specified key is null
2174	>	* @param initialCapacity The implementation performs internal
2175	>	* sizing to accommodate this many elements.
2176	>	* @param <K> the element type of the returned set
2177	>	* @return the new set
2178	>	* @throws IllegalArgumentException if the initial capacity of
2179	>	* elements is negative
2180	>	* @since 1.8
2181		*/
2182	<	public boolean remove(Object key, Object value) {
2183	<	int hash = hash(key.hashCode());
2184	<	Segment<K,V> s;
1061	<	return value != null && (s = segmentForHash(hash)) != null &&
1062	<	s.remove(key, hash, value) != null;
2182	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2183	>	return new KeySetView<K,Boolean>
2184	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2185		}
2186
2187		/**
2188	<	* {@inheritDoc}
2188	>	* Returns a {@link Set} view of the keys in this map, using the
2189	>	* given common mapped value for any additions (i.e., {@link
2190	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2191	>	* This is of course only appropriate if it is acceptable to use
2192	>	* the same value for all additions from this view.
2193		*
2194	<	* @throws NullPointerException if any of the arguments are null
2194	>	* @param mappedValue the mapped value to use for any additions
2195	>	* @return the set view
2196	>	* @throws NullPointerException if the mappedValue is null
2197		*/
2198	<	public boolean replace(K key, V oldValue, V newValue) {
2199	<	int hash = hash(key.hashCode());
1072	<	if (oldValue == null || newValue == null)
2198	>	public KeySetView<K,V> keySet(V mappedValue) {
2199	>	if (mappedValue == null)
2200		throw new NullPointerException();
2201	<	Segment<K,V> s = segmentForHash(hash);
1075	<	return s != null && s.replace(key, hash, oldValue, newValue);
2201	>	return new KeySetView<K,V>(this, mappedValue);
2202		}
2203
2204	+	/* ---------------- Special Nodes -------------- */
2205	+
2206		/**
2207	<	* {@inheritDoc}
1080	<	*
1081	<	* @return the previous value associated with the specified key,
1082	<	*         or <tt>null</tt> if there was no mapping for the key
1083	<	* @throws NullPointerException if the specified key or value is null
2207	>	* A node inserted at head of bins during transfer operations.
2208		*/
2209	<	public V replace(K key, V value) {
2210	<	int hash = hash(key.hashCode());
2211	<	if (value == null)
2212	<	throw new NullPointerException();
2213	<	Segment<K,V> s = segmentForHash(hash);
2214	<	return s == null ? null : s.replace(key, hash, value);
2209	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2210	>	final Node<K,V>[] nextTable;
2211	>	ForwardingNode(Node<K,V>[] tab) {
2212	>	super(MOVED, null, null);
2213	>	this.nextTable = tab;
2214	>	}
2215	>
2216	>	Node<K,V> find(int h, Object k) {
2217	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2218	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2219	>	Node<K,V> e; int n;
2220	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2221	>	(e = tabAt(tab, (n - 1) & h)) == null)
2222	>	return null;
2223	>	for (;;) {
2224	>	int eh; K ek;
2225	>	if ((eh = e.hash) == h &&
2226	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2227	>	return e;
2228	>	if (eh < 0) {
2229	>	if (e instanceof ForwardingNode) {
2230	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2231	>	continue outer;
2232	>	}
2233	>	else
2234	>	return e.find(h, k);
2235	>	}
2236	>	if ((e = e.next) == null)
2237	>	return null;
2238	>	}
2239	>	}
2240	>	}
2241		}
2242
2243		/**
2244	<	* Removes all of the mappings from this map.
2244	>	* A place-holder node used in computeIfAbsent and compute.
2245		*/
2246	<	public void clear() {
2247	<	final Segment<K,V>[] segments = this.segments;
2248	<	for (int j = 0; j < segments.length; ++j) {
2249	<	Segment<K,V> s = segmentAt(segments, j);
2250	<	if (s != null)
2251	<	s.clear();
2246	>	static final class ReservationNode<K,V> extends Node<K,V> {
2247	>	ReservationNode() {
2248	>	super(RESERVED, null, null);
2249	>	}
2250	>
2251	>	Node<K,V> find(int h, Object k) {
2252	>	return null;
2253		}
2254		}
2255
2256	+	/* ---------------- Table Initialization and Resizing -------------- */
2257	+
2258		/**
2259	<	* Returns a {@link Set} view of the keys contained in this map.
2260	<	* The set is backed by the map, so changes to the map are
2261	<	* reflected in the set, and vice-versa.  The set supports element
2262	<	* removal, which removes the corresponding mapping from this map,
2263	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1111	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1112	<	* operations.  It does not support the <tt>add</tt> or
1113	<	* <tt>addAll</tt> operations.
1114	<	*
1115	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1116	<	* that will never throw {@link ConcurrentModificationException},
1117	<	* and guarantees to traverse elements as they existed upon
1118	<	* construction of the iterator, and may (but is not guaranteed to)
1119	<	* reflect any modifications subsequent to construction.
1120	<	*/
1121	<	public Set<K> keySet() {
1122	<	Set<K> ks = keySet;
1123	<	return (ks != null) ? ks : (keySet = new KeySet());
2259	>	* Returns the stamp bits for resizing a table of size n.
2260	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2261	>	*/
2262	>	static final int resizeStamp(int n) {
2263	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2264		}
2265
2266		/**
2267	<	* Returns a {@link Collection} view of the values contained in this map.
1128	<	* The collection is backed by the map, so changes to the map are
1129	<	* reflected in the collection, and vice-versa.  The collection
1130	<	* supports element removal, which removes the corresponding
1131	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1132	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
1133	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
1134	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
1135	<	*
1136	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1137	<	* that will never throw {@link ConcurrentModificationException},
1138	<	* and guarantees to traverse elements as they existed upon
1139	<	* construction of the iterator, and may (but is not guaranteed to)
1140	<	* reflect any modifications subsequent to construction.
2267	>	* Initializes table, using the size recorded in sizeCtl.
2268		*/
2269	<	public Collection<V> values() {
2270	<	Collection<V> vs = values;
2271	<	return (vs != null) ? vs : (values = new Values());
2269	>	private final Node<K,V>[] initTable() {
2270	>	Node<K,V>[] tab; int sc;
2271	>	while ((tab = table) == null || tab.length == 0) {
2272	>	if ((sc = sizeCtl) < 0)
2273	>	Thread.yield(); // lost initialization race; just spin
2274	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2275	>	try {
2276	>	if ((tab = table) == null || tab.length == 0) {
2277	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2278	>	@SuppressWarnings("unchecked")
2279	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2280	>	table = tab = nt;
2281	>	sc = n - (n >>> 2);
2282	>	}
2283	>	} finally {
2284	>	sizeCtl = sc;
2285	>	}
2286	>	break;
2287	>	}
2288	>	}
2289	>	return tab;
2290		}
2291
2292		/**
2293	<	* Returns a {@link Set} view of the mappings contained in this map.
2294	<	* The set is backed by the map, so changes to the map are
2295	<	* reflected in the set, and vice-versa.  The set supports element
2296	<	* removal, which removes the corresponding mapping from the map,
2297	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2298	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2299	<	* operations.  It does not support the <tt>add</tt> or
2300	<	* <tt>addAll</tt> operations.
1156	<	*
1157	<	* <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.
2293	>	* Adds to count, and if table is too small and not already
2294	>	* resizing, initiates transfer. If already resizing, helps
2295	>	* perform transfer if work is available.  Rechecks occupancy
2296	>	* after a transfer to see if another resize is already needed
2297	>	* because resizings are lagging additions.
2298	>	*
2299	>	* @param x the count to add
2300	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2301		*/
2302	<	public Set<Map.Entry<K,V>> entrySet() {
2303	<	Set<Map.Entry<K,V>> es = entrySet;
2304	<	return (es != null) ? es : (entrySet = new EntrySet());
2302	>	private final void addCount(long x, int check) {
2303	>	CounterCell[] as; long b, s;
2304	>	if ((as = counterCells) != null ||
2305	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2306	>	CounterCell a; long v; int m;
2307	>	boolean uncontended = true;
2308	>	if (as == null || (m = as.length - 1) < 0 ||
2309	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2310	>	!(uncontended =
2311	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2312	>	fullAddCount(x, uncontended);
2313	>	return;
2314	>	}
2315	>	if (check <= 1)
2316	>	return;
2317	>	s = sumCount();
2318	>	}
2319	>	if (check >= 0) {
2320	>	Node<K,V>[] tab, nt; int n, sc;
2321	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2322	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2323	>	int rs = resizeStamp(n);
2324	>	if (sc < 0) {
2325	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2326	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2327	>	transferIndex <= 0)
2328	>	break;
2329	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2330	>	transfer(tab, nt);
2331	>	}
2332	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2333	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2334	>	transfer(tab, null);
2335	>	s = sumCount();
2336	>	}
2337	>	}
2338		}
2339
2340		/**
2341	<	* Returns an enumeration of the keys in this table.
1170	<	*
1171	<	* @return an enumeration of the keys in this table
1172	<	* @see #keySet()
2341	>	* Helps transfer if a resize is in progress.
2342		*/
2343	<	public Enumeration<K> keys() {
2344	<	return new KeyIterator();
2343	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2344	>	Node<K,V>[] nextTab; int sc;
2345	>	if (tab != null && (f instanceof ForwardingNode) &&
2346	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2347	>	int rs = resizeStamp(tab.length);
2348	>	while (nextTab == nextTable && table == tab &&
2349	>	(sc = sizeCtl) < 0) {
2350	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2351	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2352	>	break;
2353	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2354	>	transfer(tab, nextTab);
2355	>	break;
2356	>	}
2357	>	}
2358	>	return nextTab;
2359	>	}
2360	>	return table;
2361		}
2362
2363		/**
2364	<	* Returns an enumeration of the values in this table.
2364	>	* Tries to presize table to accommodate the given number of elements.
2365		*
2366	<	* @return an enumeration of the values in this table
1182	<	* @see #values()
2366	>	* @param size number of elements (doesn't need to be perfectly accurate)
2367		*/
2368	<	public Enumeration<V> elements() {
2369	<	return new ValueIterator();
2368	>	private final void tryPresize(int size) {
2369	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2370	>	tableSizeFor(size + (size >>> 1) + 1);
2371	>	int sc;
2372	>	while ((sc = sizeCtl) >= 0) {
2373	>	Node<K,V>[] tab = table; int n;
2374	>	if (tab == null || (n = tab.length) == 0) {
2375	>	n = (sc > c) ? sc : c;
2376	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2377	>	try {
2378	>	if (table == tab) {
2379	>	@SuppressWarnings("unchecked")
2380	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2381	>	table = nt;
2382	>	sc = n - (n >>> 2);
2383	>	}
2384	>	} finally {
2385	>	sizeCtl = sc;
2386	>	}
2387	>	}
2388	>	}
2389	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2390	>	break;
2391	>	else if (tab == table) {
2392	>	int rs = resizeStamp(n);
2393	>	if (U.compareAndSwapInt(this, SIZECTL, sc,
2394	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2395	>	transfer(tab, null);
2396	>	}
2397	>	}
2398		}
2399
2400	<	/* ---------------- Iterator Support -------------- */
2400	>	/**
2401	>	* Moves and/or copies the nodes in each bin to new table. See
2402	>	* above for explanation.
2403	>	*/
2404	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2405	>	int n = tab.length, stride;
2406	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2407	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2408	>	if (nextTab == null) {            // initiating
2409	>	try {
2410	>	@SuppressWarnings("unchecked")
2411	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2412	>	nextTab = nt;
2413	>	} catch (Throwable ex) {      // try to cope with OOME
2414	>	sizeCtl = Integer.MAX_VALUE;
2415	>	return;
2416	>	}
2417	>	nextTable = nextTab;
2418	>	transferIndex = n;
2419	>	}
2420	>	int nextn = nextTab.length;
2421	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2422	>	boolean advance = true;
2423	>	boolean finishing = false; // to ensure sweep before committing nextTab
2424	>	for (int i = 0, bound = 0;;) {
2425	>	Node<K,V> f; int fh;
2426	>	while (advance) {
2427	>	int nextIndex, nextBound;
2428	>	if (--i >= bound || finishing)
2429	>	advance = false;
2430	>	else if ((nextIndex = transferIndex) <= 0) {
2431	>	i = -1;
2432	>	advance = false;
2433	>	}
2434	>	else if (U.compareAndSwapInt
2435	>	(this, TRANSFERINDEX, nextIndex,
2436	>	nextBound = (nextIndex > stride ?
2437	>	nextIndex - stride : 0))) {
2438	>	bound = nextBound;
2439	>	i = nextIndex - 1;
2440	>	advance = false;
2441	>	}
2442	>	}
2443	>	if (i < 0 || i >= n || i + n >= nextn) {
2444	>	int sc;
2445	>	if (finishing) {
2446	>	nextTable = null;
2447	>	table = nextTab;
2448	>	sizeCtl = (n << 1) - (n >>> 1);
2449	>	return;
2450	>	}
2451	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2452	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2453	>	return;
2454	>	finishing = advance = true;
2455	>	i = n; // recheck before commit
2456	>	}
2457	>	}
2458	>	else if ((f = tabAt(tab, i)) == null)
2459	>	advance = casTabAt(tab, i, null, fwd);
2460	>	else if ((fh = f.hash) == MOVED)
2461	>	advance = true; // already processed
2462	>	else {
2463	>	synchronized (f) {
2464	>	if (tabAt(tab, i) == f) {
2465	>	Node<K,V> ln, hn;
2466	>	if (fh >= 0) {
2467	>	int runBit = fh & n;
2468	>	Node<K,V> lastRun = f;
2469	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2470	>	int b = p.hash & n;
2471	>	if (b != runBit) {
2472	>	runBit = b;
2473	>	lastRun = p;
2474	>	}
2475	>	}
2476	>	if (runBit == 0) {
2477	>	ln = lastRun;
2478	>	hn = null;
2479	>	}
2480	>	else {
2481	>	hn = lastRun;
2482	>	ln = null;
2483	>	}
2484	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2485	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2486	>	if ((ph & n) == 0)
2487	>	ln = new Node<K,V>(ph, pk, pv, ln);
2488	>	else
2489	>	hn = new Node<K,V>(ph, pk, pv, hn);
2490	>	}
2491	>	setTabAt(nextTab, i, ln);
2492	>	setTabAt(nextTab, i + n, hn);
2493	>	setTabAt(tab, i, fwd);
2494	>	advance = true;
2495	>	}
2496	>	else if (f instanceof TreeBin) {
2497	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2498	>	TreeNode<K,V> lo = null, loTail = null;
2499	>	TreeNode<K,V> hi = null, hiTail = null;
2500	>	int lc = 0, hc = 0;
2501	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2502	>	int h = e.hash;
2503	>	TreeNode<K,V> p = new TreeNode<K,V>
2504	>	(h, e.key, e.val, null, null);
2505	>	if ((h & n) == 0) {
2506	>	if ((p.prev = loTail) == null)
2507	>	lo = p;
2508	>	else
2509	>	loTail.next = p;
2510	>	loTail = p;
2511	>	++lc;
2512	>	}
2513	>	else {
2514	>	if ((p.prev = hiTail) == null)
2515	>	hi = p;
2516	>	else
2517	>	hiTail.next = p;
2518	>	hiTail = p;
2519	>	++hc;
2520	>	}
2521	>	}
2522	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2523	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2524	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2525	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2526	>	setTabAt(nextTab, i, ln);
2527	>	setTabAt(nextTab, i + n, hn);
2528	>	setTabAt(tab, i, fwd);
2529	>	advance = true;
2530	>	}
2531	>	}
2532	>	}
2533	>	}
2534	>	}
2535	>	}
2536
2537	<	abstract class HashIterator {
1191	<	int nextSegmentIndex;
1192	<	int nextTableIndex;
1193	<	HashEntry<K,V>[] currentTable;
1194	<	HashEntry<K, V> nextEntry;
1195	<	HashEntry<K, V> lastReturned;
2537	>	/* ---------------- Counter support -------------- */
2538
2539	<	HashIterator() {
2540	<	nextSegmentIndex = segments.length - 1;
2541	<	nextTableIndex = -1;
2542	<	advance();
2539	>	/**
2540	>	* A padded cell for distributing counts.  Adapted from LongAdder
2541	>	* and Striped64.  See their internal docs for explanation.
2542	>	*/
2543	>	@jdk.internal.vm.annotation.Contended static final class CounterCell {
2544	>	volatile long value;
2545	>	CounterCell(long x) { value = x; }
2546	>	}
2547	>
2548	>	final long sumCount() {
2549	>	CounterCell[] as = counterCells; CounterCell a;
2550	>	long sum = baseCount;
2551	>	if (as != null) {
2552	>	for (int i = 0; i < as.length; ++i) {
2553	>	if ((a = as[i]) != null)
2554	>	sum += a.value;
2555	>	}
2556	>	}
2557	>	return sum;
2558	>	}
2559	>
2560	>	// See LongAdder version for explanation
2561	>	private final void fullAddCount(long x, boolean wasUncontended) {
2562	>	int h;
2563	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2564	>	ThreadLocalRandom.localInit();      // force initialization
2565	>	h = ThreadLocalRandom.getProbe();
2566	>	wasUncontended = true;
2567	>	}
2568	>	boolean collide = false;                // True if last slot nonempty
2569	>	for (;;) {
2570	>	CounterCell[] as; CounterCell a; int n; long v;
2571	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2572	>	if ((a = as[(n - 1) & h]) == null) {
2573	>	if (cellsBusy == 0) {            // Try to attach new Cell
2574	>	CounterCell r = new CounterCell(x); // Optimistic create
2575	>	if (cellsBusy == 0 &&
2576	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2577	>	boolean created = false;
2578	>	try {               // Recheck under lock
2579	>	CounterCell[] rs; int m, j;
2580	>	if ((rs = counterCells) != null &&
2581	>	(m = rs.length) > 0 &&
2582	>	rs[j = (m - 1) & h] == null) {
2583	>	rs[j] = r;
2584	>	created = true;
2585	>	}
2586	>	} finally {
2587	>	cellsBusy = 0;
2588	>	}
2589	>	if (created)
2590	>	break;
2591	>	continue;           // Slot is now non-empty
2592	>	}
2593	>	}
2594	>	collide = false;
2595	>	}
2596	>	else if (!wasUncontended)       // CAS already known to fail
2597	>	wasUncontended = true;      // Continue after rehash
2598	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2599	>	break;
2600	>	else if (counterCells != as || n >= NCPU)
2601	>	collide = false;            // At max size or stale
2602	>	else if (!collide)
2603	>	collide = true;
2604	>	else if (cellsBusy == 0 &&
2605	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2606	>	try {
2607	>	if (counterCells == as) {// Expand table unless stale
2608	>	CounterCell[] rs = new CounterCell[n << 1];
2609	>	for (int i = 0; i < n; ++i)
2610	>	rs[i] = as[i];
2611	>	counterCells = rs;
2612	>	}
2613	>	} finally {
2614	>	cellsBusy = 0;
2615	>	}
2616	>	collide = false;
2617	>	continue;                   // Retry with expanded table
2618	>	}
2619	>	h = ThreadLocalRandom.advanceProbe(h);
2620	>	}
2621	>	else if (cellsBusy == 0 && counterCells == as &&
2622	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2623	>	boolean init = false;
2624	>	try {                           // Initialize table
2625	>	if (counterCells == as) {
2626	>	CounterCell[] rs = new CounterCell[2];
2627	>	rs[h & 1] = new CounterCell(x);
2628	>	counterCells = rs;
2629	>	init = true;
2630	>	}
2631	>	} finally {
2632	>	cellsBusy = 0;
2633	>	}
2634	>	if (init)
2635	>	break;
2636	>	}
2637	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2638	>	break;                          // Fall back on using base
2639	>	}
2640	>	}
2641	>
2642	>	/* ---------------- Conversion from/to TreeBins -------------- */
2643	>
2644	>	/**
2645	>	* Replaces all linked nodes in bin at given index unless table is
2646	>	* too small, in which case resizes instead.
2647	>	*/
2648	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2649	>	Node<K,V> b; int n;
2650	>	if (tab != null) {
2651	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2652	>	tryPresize(n << 1);
2653	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2654	>	synchronized (b) {
2655	>	if (tabAt(tab, index) == b) {
2656	>	TreeNode<K,V> hd = null, tl = null;
2657	>	for (Node<K,V> e = b; e != null; e = e.next) {
2658	>	TreeNode<K,V> p =
2659	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2660	>	null, null);
2661	>	if ((p.prev = tl) == null)
2662	>	hd = p;
2663	>	else
2664	>	tl.next = p;
2665	>	tl = p;
2666	>	}
2667	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2668	>	}
2669	>	}
2670	>	}
2671	>	}
2672	>	}
2673	>
2674	>	/**
2675	>	* Returns a list of non-TreeNodes replacing those in given list.
2676	>	*/
2677	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2678	>	Node<K,V> hd = null, tl = null;
2679	>	for (Node<K,V> q = b; q != null; q = q.next) {
2680	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val);
2681	>	if (tl == null)
2682	>	hd = p;
2683	>	else
2684	>	tl.next = p;
2685	>	tl = p;
2686	>	}
2687	>	return hd;
2688	>	}
2689	>
2690	>	/* ---------------- TreeNodes -------------- */
2691	>
2692	>	/**
2693	>	* Nodes for use in TreeBins.
2694	>	*/
2695	>	static final class TreeNode<K,V> extends Node<K,V> {
2696	>	TreeNode<K,V> parent;  // red-black tree links
2697	>	TreeNode<K,V> left;
2698	>	TreeNode<K,V> right;
2699	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2700	>	boolean red;
2701	>
2702	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2703	>	TreeNode<K,V> parent) {
2704	>	super(hash, key, val, next);
2705	>	this.parent = parent;
2706	>	}
2707	>
2708	>	Node<K,V> find(int h, Object k) {
2709	>	return findTreeNode(h, k, null);
2710		}
2711
2712		/**
2713	<	* Set nextEntry to first node of next non-empty table
2714	<	* (in backwards order, to simplify checks).
2713	>	* Returns the TreeNode (or null if not found) for the given key
2714	>	* starting at given root.
2715		*/
2716	<	final void advance() {
2717	<	for (;;) {
2718	<	if (nextTableIndex >= 0) {
2719	<	if ((nextEntry = entryAt(currentTable,
2720	<	nextTableIndex--)) != null)
2721	<	break;
2716	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2717	>	if (k != null) {
2718	>	TreeNode<K,V> p = this;
2719	>	do {
2720	>	int ph, dir; K pk; TreeNode<K,V> q;
2721	>	TreeNode<K,V> pl = p.left, pr = p.right;
2722	>	if ((ph = p.hash) > h)
2723	>	p = pl;
2724	>	else if (ph < h)
2725	>	p = pr;
2726	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2727	>	return p;
2728	>	else if (pl == null)
2729	>	p = pr;
2730	>	else if (pr == null)
2731	>	p = pl;
2732	>	else if ((kc != null ||
2733	>	(kc = comparableClassFor(k)) != null) &&
2734	>	(dir = compareComparables(kc, k, pk)) != 0)
2735	>	p = (dir < 0) ? pl : pr;
2736	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2737	>	return q;
2738	>	else
2739	>	p = pl;
2740	>	} while (p != null);
2741	>	}
2742	>	return null;
2743	>	}
2744	>	}
2745	>
2746	>	/* ---------------- TreeBins -------------- */
2747	>
2748	>	/**
2749	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2750	>	* keys or values, but instead point to list of TreeNodes and
2751	>	* their root. They also maintain a parasitic read-write lock
2752	>	* forcing writers (who hold bin lock) to wait for readers (who do
2753	>	* not) to complete before tree restructuring operations.
2754	>	*/
2755	>	static final class TreeBin<K,V> extends Node<K,V> {
2756	>	TreeNode<K,V> root;
2757	>	volatile TreeNode<K,V> first;
2758	>	volatile Thread waiter;
2759	>	volatile int lockState;
2760	>	// values for lockState
2761	>	static final int WRITER = 1; // set while holding write lock
2762	>	static final int WAITER = 2; // set when waiting for write lock
2763	>	static final int READER = 4; // increment value for setting read lock
2764	>
2765	>	/**
2766	>	* Tie-breaking utility for ordering insertions when equal
2767	>	* hashCodes and non-comparable. We don't require a total
2768	>	* order, just a consistent insertion rule to maintain
2769	>	* equivalence across rebalancings. Tie-breaking further than
2770	>	* necessary simplifies testing a bit.
2771	>	*/
2772	>	static int tieBreakOrder(Object a, Object b) {
2773	>	int d;
2774	>	if (a == null || b == null ||
2775	>	(d = a.getClass().getName().
2776	>	compareTo(b.getClass().getName())) == 0)
2777	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2778	>	-1 : 1);
2779	>	return d;
2780	>	}
2781	>
2782	>	/**
2783	>	* Creates bin with initial set of nodes headed by b.
2784	>	*/
2785	>	TreeBin(TreeNode<K,V> b) {
2786	>	super(TREEBIN, null, null);
2787	>	this.first = b;
2788	>	TreeNode<K,V> r = null;
2789	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2790	>	next = (TreeNode<K,V>)x.next;
2791	>	x.left = x.right = null;
2792	>	if (r == null) {
2793	>	x.parent = null;
2794	>	x.red = false;
2795	>	r = x;
2796		}
2797	<	else if (nextSegmentIndex >= 0) {
2798	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
2799	<	if (seg != null && (currentTable = seg.table) != null)
2800	<	nextTableIndex = currentTable.length - 1;
2797	>	else {
2798	>	K k = x.key;
2799	>	int h = x.hash;
2800	>	Class<?> kc = null;
2801	>	for (TreeNode<K,V> p = r;;) {
2802	>	int dir, ph;
2803	>	K pk = p.key;
2804	>	if ((ph = p.hash) > h)
2805	>	dir = -1;
2806	>	else if (ph < h)
2807	>	dir = 1;
2808	>	else if ((kc == null &&
2809	>	(kc = comparableClassFor(k)) == null) ||
2810	>	(dir = compareComparables(kc, k, pk)) == 0)
2811	>	dir = tieBreakOrder(k, pk);
2812	>	TreeNode<K,V> xp = p;
2813	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2814	>	x.parent = xp;
2815	>	if (dir <= 0)
2816	>	xp.left = x;
2817	>	else
2818	>	xp.right = x;
2819	>	r = balanceInsertion(r, x);
2820	>	break;
2821	>	}
2822	>	}
2823		}
2824	<	else
2824	>	}
2825	>	this.root = r;
2826	>	assert checkInvariants(root);
2827	>	}
2828	>
2829	>	/**
2830	>	* Acquires write lock for tree restructuring.
2831	>	*/
2832	>	private final void lockRoot() {
2833	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2834	>	contendedLock(); // offload to separate method
2835	>	}
2836	>
2837	>	/**
2838	>	* Releases write lock for tree restructuring.
2839	>	*/
2840	>	private final void unlockRoot() {
2841	>	lockState = 0;
2842	>	}
2843	>
2844	>	/**
2845	>	* Possibly blocks awaiting root lock.
2846	>	*/
2847	>	private final void contendedLock() {
2848	>	boolean waiting = false;
2849	>	for (int s;;) {
2850	>	if (((s = lockState) & ~WAITER) == 0) {
2851	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2852	>	if (waiting)
2853	>	waiter = null;
2854	>	return;
2855	>	}
2856	>	}
2857	>	else if ((s & WAITER) == 0) {
2858	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2859	>	waiting = true;
2860	>	waiter = Thread.currentThread();
2861	>	}
2862	>	}
2863	>	else if (waiting)
2864	>	LockSupport.park(this);
2865	>	}
2866	>	}
2867	>
2868	>	/**
2869	>	* Returns matching node or null if none. Tries to search
2870	>	* using tree comparisons from root, but continues linear
2871	>	* search when lock not available.
2872	>	*/
2873	>	final Node<K,V> find(int h, Object k) {
2874	>	if (k != null) {
2875	>	for (Node<K,V> e = first; e != null; ) {
2876	>	int s; K ek;
2877	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2878	>	if (e.hash == h &&
2879	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2880	>	return e;
2881	>	e = e.next;
2882	>	}
2883	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2884	>	s + READER)) {
2885	>	TreeNode<K,V> r, p;
2886	>	try {
2887	>	p = ((r = root) == null ? null :
2888	>	r.findTreeNode(h, k, null));
2889	>	} finally {
2890	>	Thread w;
2891	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2892	>	(READER|WAITER) && (w = waiter) != null)
2893	>	LockSupport.unpark(w);
2894	>	}
2895	>	return p;
2896	>	}
2897	>	}
2898	>	}
2899	>	return null;
2900	>	}
2901	>
2902	>	/**
2903	>	* Finds or adds a node.
2904	>	* @return null if added
2905	>	*/
2906	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2907	>	Class<?> kc = null;
2908	>	boolean searched = false;
2909	>	for (TreeNode<K,V> p = root;;) {
2910	>	int dir, ph; K pk;
2911	>	if (p == null) {
2912	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2913	>	break;
2914	>	}
2915	>	else if ((ph = p.hash) > h)
2916	>	dir = -1;
2917	>	else if (ph < h)
2918	>	dir = 1;
2919	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2920	>	return p;
2921	>	else if ((kc == null &&
2922	>	(kc = comparableClassFor(k)) == null) ||
2923	>	(dir = compareComparables(kc, k, pk)) == 0) {
2924	>	if (!searched) {
2925	>	TreeNode<K,V> q, ch;
2926	>	searched = true;
2927	>	if (((ch = p.left) != null &&
2928	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2929	>	((ch = p.right) != null &&
2930	>	(q = ch.findTreeNode(h, k, kc)) != null))
2931	>	return q;
2932	>	}
2933	>	dir = tieBreakOrder(k, pk);
2934	>	}
2935	>
2936	>	TreeNode<K,V> xp = p;
2937	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2938	>	TreeNode<K,V> x, f = first;
2939	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2940	>	if (f != null)
2941	>	f.prev = x;
2942	>	if (dir <= 0)
2943	>	xp.left = x;
2944	>	else
2945	>	xp.right = x;
2946	>	if (!xp.red)
2947	>	x.red = true;
2948	>	else {
2949	>	lockRoot();
2950	>	try {
2951	>	root = balanceInsertion(root, x);
2952	>	} finally {
2953	>	unlockRoot();
2954	>	}
2955	>	}
2956		break;
2957	+	}
2958		}
2959	+	assert checkInvariants(root);
2960	+	return null;
2961		}
2962
2963	<	final HashEntry<K,V> nextEntry() {
2964	<	HashEntry<K,V> e = lastReturned = nextEntry;
2965	<	if (e == null)
2966	<	throw new NoSuchElementException();
2967	<	if ((nextEntry = e.next) == null)
2968	<	advance();
2969	<	return e;
2963	>	/**
2964	>	* Removes the given node, that must be present before this
2965	>	* call.  This is messier than typical red-black deletion code
2966	>	* because we cannot swap the contents of an interior node
2967	>	* with a leaf successor that is pinned by "next" pointers
2968	>	* that are accessible independently of lock. So instead we
2969	>	* swap the tree linkages.
2970	>	*
2971	>	* @return true if now too small, so should be untreeified
2972	>	*/
2973	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2974	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2975	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2976	>	TreeNode<K,V> r, rl;
2977	>	if (pred == null)
2978	>	first = next;
2979	>	else
2980	>	pred.next = next;
2981	>	if (next != null)
2982	>	next.prev = pred;
2983	>	if (first == null) {
2984	>	root = null;
2985	>	return true;
2986	>	}
2987	>	if ((r = root) == null || r.right == null || // too small
2988	>	(rl = r.left) == null || rl.left == null)
2989	>	return true;
2990	>	lockRoot();
2991	>	try {
2992	>	TreeNode<K,V> replacement;
2993	>	TreeNode<K,V> pl = p.left;
2994	>	TreeNode<K,V> pr = p.right;
2995	>	if (pl != null && pr != null) {
2996	>	TreeNode<K,V> s = pr, sl;
2997	>	while ((sl = s.left) != null) // find successor
2998	>	s = sl;
2999	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
3000	>	TreeNode<K,V> sr = s.right;
3001	>	TreeNode<K,V> pp = p.parent;
3002	>	if (s == pr) { // p was s's direct parent
3003	>	p.parent = s;
3004	>	s.right = p;
3005	>	}
3006	>	else {
3007	>	TreeNode<K,V> sp = s.parent;
3008	>	if ((p.parent = sp) != null) {
3009	>	if (s == sp.left)
3010	>	sp.left = p;
3011	>	else
3012	>	sp.right = p;
3013	>	}
3014	>	if ((s.right = pr) != null)
3015	>	pr.parent = s;
3016	>	}
3017	>	p.left = null;
3018	>	if ((p.right = sr) != null)
3019	>	sr.parent = p;
3020	>	if ((s.left = pl) != null)
3021	>	pl.parent = s;
3022	>	if ((s.parent = pp) == null)
3023	>	r = s;
3024	>	else if (p == pp.left)
3025	>	pp.left = s;
3026	>	else
3027	>	pp.right = s;
3028	>	if (sr != null)
3029	>	replacement = sr;
3030	>	else
3031	>	replacement = p;
3032	>	}
3033	>	else if (pl != null)
3034	>	replacement = pl;
3035	>	else if (pr != null)
3036	>	replacement = pr;
3037	>	else
3038	>	replacement = p;
3039	>	if (replacement != p) {
3040	>	TreeNode<K,V> pp = replacement.parent = p.parent;
3041	>	if (pp == null)
3042	>	r = replacement;
3043	>	else if (p == pp.left)
3044	>	pp.left = replacement;
3045	>	else
3046	>	pp.right = replacement;
3047	>	p.left = p.right = p.parent = null;
3048	>	}
3049	>
3050	>	root = (p.red) ? r : balanceDeletion(r, replacement);
3051	>
3052	>	if (p == replacement) {  // detach pointers
3053	>	TreeNode<K,V> pp;
3054	>	if ((pp = p.parent) != null) {
3055	>	if (p == pp.left)
3056	>	pp.left = null;
3057	>	else if (p == pp.right)
3058	>	pp.right = null;
3059	>	p.parent = null;
3060	>	}
3061	>	}
3062	>	} finally {
3063	>	unlockRoot();
3064	>	}
3065	>	assert checkInvariants(root);
3066	>	return false;
3067	>	}
3068	>
3069	>	/* ------------------------------------------------------------ */
3070	>	// Red-black tree methods, all adapted from CLR
3071	>
3072	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3073	>	TreeNode<K,V> p) {
3074	>	TreeNode<K,V> r, pp, rl;
3075	>	if (p != null && (r = p.right) != null) {
3076	>	if ((rl = p.right = r.left) != null)
3077	>	rl.parent = p;
3078	>	if ((pp = r.parent = p.parent) == null)
3079	>	(root = r).red = false;
3080	>	else if (pp.left == p)
3081	>	pp.left = r;
3082	>	else
3083	>	pp.right = r;
3084	>	r.left = p;
3085	>	p.parent = r;
3086	>	}
3087	>	return root;
3088		}
3089
3090	<	public final boolean hasNext() { return nextEntry != null; }
3091	<	public final boolean hasMoreElements() { return nextEntry != null; }
3090	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3091	>	TreeNode<K,V> p) {
3092	>	TreeNode<K,V> l, pp, lr;
3093	>	if (p != null && (l = p.left) != null) {
3094	>	if ((lr = p.left = l.right) != null)
3095	>	lr.parent = p;
3096	>	if ((pp = l.parent = p.parent) == null)
3097	>	(root = l).red = false;
3098	>	else if (pp.right == p)
3099	>	pp.right = l;
3100	>	else
3101	>	pp.left = l;
3102	>	l.right = p;
3103	>	p.parent = l;
3104	>	}
3105	>	return root;
3106	>	}
3107	>
3108	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3109	>	TreeNode<K,V> x) {
3110	>	x.red = true;
3111	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3112	>	if ((xp = x.parent) == null) {
3113	>	x.red = false;
3114	>	return x;
3115	>	}
3116	>	else if (!xp.red || (xpp = xp.parent) == null)
3117	>	return root;
3118	>	if (xp == (xppl = xpp.left)) {
3119	>	if ((xppr = xpp.right) != null && xppr.red) {
3120	>	xppr.red = false;
3121	>	xp.red = false;
3122	>	xpp.red = true;
3123	>	x = xpp;
3124	>	}
3125	>	else {
3126	>	if (x == xp.right) {
3127	>	root = rotateLeft(root, x = xp);
3128	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3129	>	}
3130	>	if (xp != null) {
3131	>	xp.red = false;
3132	>	if (xpp != null) {
3133	>	xpp.red = true;
3134	>	root = rotateRight(root, xpp);
3135	>	}
3136	>	}
3137	>	}
3138	>	}
3139	>	else {
3140	>	if (xppl != null && xppl.red) {
3141	>	xppl.red = false;
3142	>	xp.red = false;
3143	>	xpp.red = true;
3144	>	x = xpp;
3145	>	}
3146	>	else {
3147	>	if (x == xp.left) {
3148	>	root = rotateRight(root, x = xp);
3149	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3150	>	}
3151	>	if (xp != null) {
3152	>	xp.red = false;
3153	>	if (xpp != null) {
3154	>	xpp.red = true;
3155	>	root = rotateLeft(root, xpp);
3156	>	}
3157	>	}
3158	>	}
3159	>	}
3160	>	}
3161	>	}
3162	>
3163	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3164	>	TreeNode<K,V> x) {
3165	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3166	>	if (x == null || x == root)
3167	>	return root;
3168	>	else if ((xp = x.parent) == null) {
3169	>	x.red = false;
3170	>	return x;
3171	>	}
3172	>	else if (x.red) {
3173	>	x.red = false;
3174	>	return root;
3175	>	}
3176	>	else if ((xpl = xp.left) == x) {
3177	>	if ((xpr = xp.right) != null && xpr.red) {
3178	>	xpr.red = false;
3179	>	xp.red = true;
3180	>	root = rotateLeft(root, xp);
3181	>	xpr = (xp = x.parent) == null ? null : xp.right;
3182	>	}
3183	>	if (xpr == null)
3184	>	x = xp;
3185	>	else {
3186	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3187	>	if ((sr == null || !sr.red) &&
3188	>	(sl == null || !sl.red)) {
3189	>	xpr.red = true;
3190	>	x = xp;
3191	>	}
3192	>	else {
3193	>	if (sr == null || !sr.red) {
3194	>	if (sl != null)
3195	>	sl.red = false;
3196	>	xpr.red = true;
3197	>	root = rotateRight(root, xpr);
3198	>	xpr = (xp = x.parent) == null ?
3199	>	null : xp.right;
3200	>	}
3201	>	if (xpr != null) {
3202	>	xpr.red = (xp == null) ? false : xp.red;
3203	>	if ((sr = xpr.right) != null)
3204	>	sr.red = false;
3205	>	}
3206	>	if (xp != null) {
3207	>	xp.red = false;
3208	>	root = rotateLeft(root, xp);
3209	>	}
3210	>	x = root;
3211	>	}
3212	>	}
3213	>	}
3214	>	else { // symmetric
3215	>	if (xpl != null && xpl.red) {
3216	>	xpl.red = false;
3217	>	xp.red = true;
3218	>	root = rotateRight(root, xp);
3219	>	xpl = (xp = x.parent) == null ? null : xp.left;
3220	>	}
3221	>	if (xpl == null)
3222	>	x = xp;
3223	>	else {
3224	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3225	>	if ((sl == null || !sl.red) &&
3226	>	(sr == null || !sr.red)) {
3227	>	xpl.red = true;
3228	>	x = xp;
3229	>	}
3230	>	else {
3231	>	if (sl == null || !sl.red) {
3232	>	if (sr != null)
3233	>	sr.red = false;
3234	>	xpl.red = true;
3235	>	root = rotateLeft(root, xpl);
3236	>	xpl = (xp = x.parent) == null ?
3237	>	null : xp.left;
3238	>	}
3239	>	if (xpl != null) {
3240	>	xpl.red = (xp == null) ? false : xp.red;
3241	>	if ((sl = xpl.left) != null)
3242	>	sl.red = false;
3243	>	}
3244	>	if (xp != null) {
3245	>	xp.red = false;
3246	>	root = rotateRight(root, xp);
3247	>	}
3248	>	x = root;
3249	>	}
3250	>	}
3251	>	}
3252	>	}
3253	>	}
3254	>
3255	>	/**
3256	>	* Checks invariants recursively for the tree of Nodes rooted at t.
3257	>	*/
3258	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3259	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3260	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3261	>	if (tb != null && tb.next != t)
3262	>	return false;
3263	>	if (tn != null && tn.prev != t)
3264	>	return false;
3265	>	if (tp != null && t != tp.left && t != tp.right)
3266	>	return false;
3267	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3268	>	return false;
3269	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3270	>	return false;
3271	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3272	>	return false;
3273	>	if (tl != null && !checkInvariants(tl))
3274	>	return false;
3275	>	if (tr != null && !checkInvariants(tr))
3276	>	return false;
3277	>	return true;
3278	>	}
3279	>
3280	>	private static final Unsafe U = Unsafe.getUnsafe();
3281	>	private static final long LOCKSTATE;
3282	>	static {
3283	>	try {
3284	>	LOCKSTATE = U.objectFieldOffset
3285	>	(TreeBin.class.getDeclaredField("lockState"));
3286	>	} catch (ReflectiveOperationException e) {
3287	>	throw new Error(e);
3288	>	}
3289	>	}
3290	>	}
3291	>
3292	>	/* ----------------Table Traversal -------------- */
3293	>
3294	>	/**
3295	>	* Records the table, its length, and current traversal index for a
3296	>	* traverser that must process a region of a forwarded table before
3297	>	* proceeding with current table.
3298	>	*/
3299	>	static final class TableStack<K,V> {
3300	>	int length;
3301	>	int index;
3302	>	Node<K,V>[] tab;
3303	>	TableStack<K,V> next;
3304	>	}
3305	>
3306	>	/**
3307	>	* Encapsulates traversal for methods such as containsValue; also
3308	>	* serves as a base class for other iterators and spliterators.
3309	>	*
3310	>	* Method advance visits once each still-valid node that was
3311	>	* reachable upon iterator construction. It might miss some that
3312	>	* were added to a bin after the bin was visited, which is OK wrt
3313	>	* consistency guarantees. Maintaining this property in the face
3314	>	* of possible ongoing resizes requires a fair amount of
3315	>	* bookkeeping state that is difficult to optimize away amidst
3316	>	* volatile accesses.  Even so, traversal maintains reasonable
3317	>	* throughput.
3318	>	*
3319	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3320	>	* However, if the table has been resized, then all future steps
3321	>	* must traverse both the bin at the current index as well as at
3322	>	* (index + baseSize); and so on for further resizings. To
3323	>	* paranoically cope with potential sharing by users of iterators
3324	>	* across threads, iteration terminates if a bounds checks fails
3325	>	* for a table read.
3326	>	*/
3327	>	static class Traverser<K,V> {
3328	>	Node<K,V>[] tab;        // current table; updated if resized
3329	>	Node<K,V> next;         // the next entry to use
3330	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3331	>	int index;              // index of bin to use next
3332	>	int baseIndex;          // current index of initial table
3333	>	int baseLimit;          // index bound for initial table
3334	>	final int baseSize;     // initial table size
3335	>
3336	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3337	>	this.tab = tab;
3338	>	this.baseSize = size;
3339	>	this.baseIndex = this.index = index;
3340	>	this.baseLimit = limit;
3341	>	this.next = null;
3342	>	}
3343	>
3344	>	/**
3345	>	* Advances if possible, returning next valid node, or null if none.
3346	>	*/
3347	>	final Node<K,V> advance() {
3348	>	Node<K,V> e;
3349	>	if ((e = next) != null)
3350	>	e = e.next;
3351	>	for (;;) {
3352	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3353	>	if (e != null)
3354	>	return next = e;
3355	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3356	>	(n = t.length) <= (i = index) || i < 0)
3357	>	return next = null;
3358	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3359	>	if (e instanceof ForwardingNode) {
3360	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3361	>	e = null;
3362	>	pushState(t, i, n);
3363	>	continue;
3364	>	}
3365	>	else if (e instanceof TreeBin)
3366	>	e = ((TreeBin<K,V>)e).first;
3367	>	else
3368	>	e = null;
3369	>	}
3370	>	if (stack != null)
3371	>	recoverState(n);
3372	>	else if ((index = i + baseSize) >= n)
3373	>	index = ++baseIndex; // visit upper slots if present
3374	>	}
3375	>	}
3376	>
3377	>	/**
3378	>	* Saves traversal state upon encountering a forwarding node.
3379	>	*/
3380	>	private void pushState(Node<K,V>[] t, int i, int n) {
3381	>	TableStack<K,V> s = spare;  // reuse if possible
3382	>	if (s != null)
3383	>	spare = s.next;
3384	>	else
3385	>	s = new TableStack<K,V>();
3386	>	s.tab = t;
3387	>	s.length = n;
3388	>	s.index = i;
3389	>	s.next = stack;
3390	>	stack = s;
3391	>	}
3392	>
3393	>	/**
3394	>	* Possibly pops traversal state.
3395	>	*
3396	>	* @param n length of current table
3397	>	*/
3398	>	private void recoverState(int n) {
3399	>	TableStack<K,V> s; int len;
3400	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3401	>	n = len;
3402	>	index = s.index;
3403	>	tab = s.tab;
3404	>	s.tab = null;
3405	>	TableStack<K,V> next = s.next;
3406	>	s.next = spare; // save for reuse
3407	>	stack = next;
3408	>	spare = s;
3409	>	}
3410	>	if (s == null && (index += baseSize) >= n)
3411	>	index = ++baseIndex;
3412	>	}
3413	>	}
3414	>
3415	>	/**
3416	>	* Base of key, value, and entry Iterators. Adds fields to
3417	>	* Traverser to support iterator.remove.
3418	>	*/
3419	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3420	>	final ConcurrentHashMap<K,V> map;
3421	>	Node<K,V> lastReturned;
3422	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3423	>	ConcurrentHashMap<K,V> map) {
3424	>	super(tab, size, index, limit);
3425	>	this.map = map;
3426	>	advance();
3427	>	}
3428	>
3429	>	public final boolean hasNext() { return next != null; }
3430	>	public final boolean hasMoreElements() { return next != null; }
3431
3432		public final void remove() {
3433	<	if (lastReturned == null)
3433	>	Node<K,V> p;
3434	>	if ((p = lastReturned) == null)
3435		throw new IllegalStateException();
1239	–	ConcurrentHashMap.this.remove(lastReturned.key);
3436		lastReturned = null;
3437	+	map.replaceNode(p.key, null, null);
3438		}
3439		}
3440
3441	<	final class KeyIterator
3442	<	extends HashIterator
3443	<	implements Iterator<K>, Enumeration<K>
3444	<	{
3445	<	public final K next()        { return super.nextEntry().key; }
3446	<	public final K nextElement() { return super.nextEntry().key; }
3441	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3442	>	implements Iterator<K>, Enumeration<K> {
3443	>	KeyIterator(Node<K,V>[] tab, int size, int index, int limit,
3444	>	ConcurrentHashMap<K,V> map) {
3445	>	super(tab, size, index, limit, map);
3446	>	}
3447	>
3448	>	public final K next() {
3449	>	Node<K,V> p;
3450	>	if ((p = next) == null)
3451	>	throw new NoSuchElementException();
3452	>	K k = p.key;
3453	>	lastReturned = p;
3454	>	advance();
3455	>	return k;
3456	>	}
3457	>
3458	>	public final K nextElement() { return next(); }
3459	>	}
3460	>
3461	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3462	>	implements Iterator<V>, Enumeration<V> {
3463	>	ValueIterator(Node<K,V>[] tab, int size, int index, int limit,
3464	>	ConcurrentHashMap<K,V> map) {
3465	>	super(tab, size, index, limit, map);
3466	>	}
3467	>
3468	>	public final V next() {
3469	>	Node<K,V> p;
3470	>	if ((p = next) == null)
3471	>	throw new NoSuchElementException();
3472	>	V v = p.val;
3473	>	lastReturned = p;
3474	>	advance();
3475	>	return v;
3476	>	}
3477	>
3478	>	public final V nextElement() { return next(); }
3479		}
3480
3481	<	final class ValueIterator
3482	<	extends HashIterator
3483	<	implements Iterator<V>, Enumeration<V>
3484	<	{
3485	<	public final V next()        { return super.nextEntry().value; }
3486	<	public final V nextElement() { return super.nextEntry().value; }
3481	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3482	>	implements Iterator<Map.Entry<K,V>> {
3483	>	EntryIterator(Node<K,V>[] tab, int size, int index, int limit,
3484	>	ConcurrentHashMap<K,V> map) {
3485	>	super(tab, size, index, limit, map);
3486	>	}
3487	>
3488	>	public final Map.Entry<K,V> next() {
3489	>	Node<K,V> p;
3490	>	if ((p = next) == null)
3491	>	throw new NoSuchElementException();
3492	>	K k = p.key;
3493	>	V v = p.val;
3494	>	lastReturned = p;
3495	>	advance();
3496	>	return new MapEntry<K,V>(k, v, map);
3497	>	}
3498		}
3499
3500		/**
3501	<	* Custom Entry class used by EntryIterator.next(), that relays
1262	<	* setValue changes to the underlying map.
3501	>	* Exported Entry for EntryIterator.
3502		*/
3503	<	final class WriteThroughEntry
3504	<	extends AbstractMap.SimpleEntry<K,V>
3505	<	{
3506	<	WriteThroughEntry(K k, V v) {
3507	<	super(k,v);
3503	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3504	>	final K key; // non-null
3505	>	V val;       // non-null
3506	>	final ConcurrentHashMap<K,V> map;
3507	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3508	>	this.key = key;
3509	>	this.val = val;
3510	>	this.map = map;
3511	>	}
3512	>	public K getKey()        { return key; }
3513	>	public V getValue()      { return val; }
3514	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3515	>	public String toString() {
3516	>	return Helpers.mapEntryToString(key, val);
3517	>	}
3518	>
3519	>	public boolean equals(Object o) {
3520	>	Object k, v; Map.Entry<?,?> e;
3521	>	return ((o instanceof Map.Entry) &&
3522	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3523	>	(v = e.getValue()) != null &&
3524	>	(k == key || k.equals(key)) &&
3525	>	(v == val || v.equals(val)));
3526		}
3527
3528		/**
3529	<	* Set our entry's value and write through to the map. The
3530	<	* value to return is somewhat arbitrary here. Since a
3531	<	* WriteThroughEntry does not necessarily track asynchronous
3532	<	* changes, the most recent "previous" value could be
3533	<	* different from what we return (or could even have been
3534	<	* removed in which case the put will re-establish). We do not
1278	<	* and cannot guarantee more.
3529	>	* Sets our entry's value and writes through to the map. The
3530	>	* value to return is somewhat arbitrary here. Since we do not
3531	>	* necessarily track asynchronous changes, the most recent
3532	>	* "previous" value could be different from what we return (or
3533	>	* could even have been removed, in which case the put will
3534	>	* re-establish). We do not and cannot guarantee more.
3535		*/
3536		public V setValue(V value) {
3537		if (value == null) throw new NullPointerException();
3538	<	V v = super.setValue(value);
3539	<	ConcurrentHashMap.this.put(getKey(), value);
3538	>	V v = val;
3539	>	val = value;
3540	>	map.put(key, value);
3541		return v;
3542		}
3543		}
3544
3545	<	final class EntryIterator
3546	<	extends HashIterator
3547	<	implements Iterator<Entry<K,V>>
3548	<	{
3549	<	public Map.Entry<K,V> next() {
3550	<	HashEntry<K,V> e = super.nextEntry();
3551	<	return new WriteThroughEntry(e.key, e.value);
3545	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3546	>	implements Spliterator<K> {
3547	>	long est;               // size estimate
3548	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3549	>	long est) {
3550	>	super(tab, size, index, limit);
3551	>	this.est = est;
3552	>	}
3553	>
3554	>	public KeySpliterator<K,V> trySplit() {
3555	>	int i, f, h;
3556	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3557	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3558	>	f, est >>>= 1);
3559	>	}
3560	>
3561	>	public void forEachRemaining(Consumer<? super K> action) {
3562	>	if (action == null) throw new NullPointerException();
3563	>	for (Node<K,V> p; (p = advance()) != null;)
3564	>	action.accept(p.key);
3565	>	}
3566	>
3567	>	public boolean tryAdvance(Consumer<? super K> action) {
3568	>	if (action == null) throw new NullPointerException();
3569	>	Node<K,V> p;
3570	>	if ((p = advance()) == null)
3571	>	return false;
3572	>	action.accept(p.key);
3573	>	return true;
3574	>	}
3575	>
3576	>	public long estimateSize() { return est; }
3577	>
3578	>	public int characteristics() {
3579	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3580	>	Spliterator.NONNULL;
3581		}
3582		}
3583
3584	<	final class KeySet extends AbstractSet<K> {
3585	<	public Iterator<K> iterator() {
3586	<	return new KeyIterator();
3584	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3585	>	implements Spliterator<V> {
3586	>	long est;               // size estimate
3587	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3588	>	long est) {
3589	>	super(tab, size, index, limit);
3590	>	this.est = est;
3591		}
3592	<	public int size() {
3593	<	return ConcurrentHashMap.this.size();
3592	>
3593	>	public ValueSpliterator<K,V> trySplit() {
3594	>	int i, f, h;
3595	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3596	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3597	>	f, est >>>= 1);
3598		}
3599	<	public boolean isEmpty() {
3600	<	return ConcurrentHashMap.this.isEmpty();
3599	>
3600	>	public void forEachRemaining(Consumer<? super V> action) {
3601	>	if (action == null) throw new NullPointerException();
3602	>	for (Node<K,V> p; (p = advance()) != null;)
3603	>	action.accept(p.val);
3604		}
3605	<	public boolean contains(Object o) {
3606	<	return ConcurrentHashMap.this.containsKey(o);
3605	>
3606	>	public boolean tryAdvance(Consumer<? super V> action) {
3607	>	if (action == null) throw new NullPointerException();
3608	>	Node<K,V> p;
3609	>	if ((p = advance()) == null)
3610	>	return false;
3611	>	action.accept(p.val);
3612	>	return true;
3613		}
3614	<	public boolean remove(Object o) {
3615	<	return ConcurrentHashMap.this.remove(o) != null;
3614	>
3615	>	public long estimateSize() { return est; }
3616	>
3617	>	public int characteristics() {
3618	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3619	>	}
3620	>	}
3621	>
3622	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3623	>	implements Spliterator<Map.Entry<K,V>> {
3624	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3625	>	long est;               // size estimate
3626	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3627	>	long est, ConcurrentHashMap<K,V> map) {
3628	>	super(tab, size, index, limit);
3629	>	this.map = map;
3630	>	this.est = est;
3631	>	}
3632	>
3633	>	public EntrySpliterator<K,V> trySplit() {
3634	>	int i, f, h;
3635	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3636	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3637	>	f, est >>>= 1, map);
3638	>	}
3639	>
3640	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3641	>	if (action == null) throw new NullPointerException();
3642	>	for (Node<K,V> p; (p = advance()) != null; )
3643	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3644	>	}
3645	>
3646	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3647	>	if (action == null) throw new NullPointerException();
3648	>	Node<K,V> p;
3649	>	if ((p = advance()) == null)
3650	>	return false;
3651	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3652	>	return true;
3653	>	}
3654	>
3655	>	public long estimateSize() { return est; }
3656	>
3657	>	public int characteristics() {
3658	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3659	>	Spliterator.NONNULL;
3660	>	}
3661	>	}
3662	>
3663	>	// Parallel bulk operations
3664	>
3665	>	/**
3666	>	* Computes initial batch value for bulk tasks. The returned value
3667	>	* is approximately exp2 of the number of times (minus one) to
3668	>	* split task by two before executing leaf action. This value is
3669	>	* faster to compute and more convenient to use as a guide to
3670	>	* splitting than is the depth, since it is used while dividing by
3671	>	* two anyway.
3672	>	*/
3673	>	final int batchFor(long b) {
3674	>	long n;
3675	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3676	>	return 0;
3677	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3678	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3679	>	}
3680	>
3681	>	/**
3682	>	* Performs the given action for each (key, value).
3683	>	*
3684	>	* @param parallelismThreshold the (estimated) number of elements
3685	>	* needed for this operation to be executed in parallel
3686	>	* @param action the action
3687	>	* @since 1.8
3688	>	*/
3689	>	public void forEach(long parallelismThreshold,
3690	>	BiConsumer<? super K,? super V> action) {
3691	>	if (action == null) throw new NullPointerException();
3692	>	new ForEachMappingTask<K,V>
3693	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3694	>	action).invoke();
3695	>	}
3696	>
3697	>	/**
3698	>	* Performs the given action for each non-null transformation
3699	>	* of each (key, value).
3700	>	*
3701	>	* @param parallelismThreshold the (estimated) number of elements
3702	>	* needed for this operation to be executed in parallel
3703	>	* @param transformer a function returning the transformation
3704	>	* for an element, or null if there is no transformation (in
3705	>	* which case the action is not applied)
3706	>	* @param action the action
3707	>	* @param <U> the return type of the transformer
3708	>	* @since 1.8
3709	>	*/
3710	>	public <U> void forEach(long parallelismThreshold,
3711	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3712	>	Consumer<? super U> action) {
3713	>	if (transformer == null || action == null)
3714	>	throw new NullPointerException();
3715	>	new ForEachTransformedMappingTask<K,V,U>
3716	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3717	>	transformer, action).invoke();
3718	>	}
3719	>
3720	>	/**
3721	>	* Returns a non-null result from applying the given search
3722	>	* function on each (key, value), or null if none.  Upon
3723	>	* success, further element processing is suppressed and the
3724	>	* results of any other parallel invocations of the search
3725	>	* function are ignored.
3726	>	*
3727	>	* @param parallelismThreshold the (estimated) number of elements
3728	>	* needed for this operation to be executed in parallel
3729	>	* @param searchFunction a function returning a non-null
3730	>	* result on success, else null
3731	>	* @param <U> the return type of the search function
3732	>	* @return a non-null result from applying the given search
3733	>	* function on each (key, value), or null if none
3734	>	* @since 1.8
3735	>	*/
3736	>	public <U> U search(long parallelismThreshold,
3737	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3738	>	if (searchFunction == null) throw new NullPointerException();
3739	>	return new SearchMappingsTask<K,V,U>
3740	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3741	>	searchFunction, new AtomicReference<U>()).invoke();
3742	>	}
3743	>
3744	>	/**
3745	>	* Returns the result of accumulating the given transformation
3746	>	* of all (key, value) pairs using the given reducer to
3747	>	* combine values, or null if none.
3748	>	*
3749	>	* @param parallelismThreshold the (estimated) number of elements
3750	>	* needed for this operation to be executed in parallel
3751	>	* @param transformer a function returning the transformation
3752	>	* for an element, or null if there is no transformation (in
3753	>	* which case it is not combined)
3754	>	* @param reducer a commutative associative combining function
3755	>	* @param <U> the return type of the transformer
3756	>	* @return the result of accumulating the given transformation
3757	>	* of all (key, value) pairs
3758	>	* @since 1.8
3759	>	*/
3760	>	public <U> U reduce(long parallelismThreshold,
3761	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3762	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3763	>	if (transformer == null || reducer == null)
3764	>	throw new NullPointerException();
3765	>	return new MapReduceMappingsTask<K,V,U>
3766	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3767	>	null, transformer, reducer).invoke();
3768	>	}
3769	>
3770	>	/**
3771	>	* Returns the result of accumulating the given transformation
3772	>	* of all (key, value) pairs using the given reducer to
3773	>	* combine values, and the given basis as an identity value.
3774	>	*
3775	>	* @param parallelismThreshold the (estimated) number of elements
3776	>	* needed for this operation to be executed in parallel
3777	>	* @param transformer a function returning the transformation
3778	>	* for an element
3779	>	* @param basis the identity (initial default value) for the reduction
3780	>	* @param reducer a commutative associative combining function
3781	>	* @return the result of accumulating the given transformation
3782	>	* of all (key, value) pairs
3783	>	* @since 1.8
3784	>	*/
3785	>	public double reduceToDouble(long parallelismThreshold,
3786	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3787	>	double basis,
3788	>	DoubleBinaryOperator reducer) {
3789	>	if (transformer == null || reducer == null)
3790	>	throw new NullPointerException();
3791	>	return new MapReduceMappingsToDoubleTask<K,V>
3792	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3793	>	null, transformer, basis, reducer).invoke();
3794	>	}
3795	>
3796	>	/**
3797	>	* Returns the result of accumulating the given transformation
3798	>	* of all (key, value) pairs using the given reducer to
3799	>	* combine values, and the given basis as an identity value.
3800	>	*
3801	>	* @param parallelismThreshold the (estimated) number of elements
3802	>	* needed for this operation to be executed in parallel
3803	>	* @param transformer a function returning the transformation
3804	>	* for an element
3805	>	* @param basis the identity (initial default value) for the reduction
3806	>	* @param reducer a commutative associative combining function
3807	>	* @return the result of accumulating the given transformation
3808	>	* of all (key, value) pairs
3809	>	* @since 1.8
3810	>	*/
3811	>	public long reduceToLong(long parallelismThreshold,
3812	>	ToLongBiFunction<? super K, ? super V> transformer,
3813	>	long basis,
3814	>	LongBinaryOperator reducer) {
3815	>	if (transformer == null || reducer == null)
3816	>	throw new NullPointerException();
3817	>	return new MapReduceMappingsToLongTask<K,V>
3818	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3819	>	null, transformer, basis, reducer).invoke();
3820	>	}
3821	>
3822	>	/**
3823	>	* Returns the result of accumulating the given transformation
3824	>	* of all (key, value) pairs using the given reducer to
3825	>	* combine values, and the given basis as an identity value.
3826	>	*
3827	>	* @param parallelismThreshold the (estimated) number of elements
3828	>	* needed for this operation to be executed in parallel
3829	>	* @param transformer a function returning the transformation
3830	>	* for an element
3831	>	* @param basis the identity (initial default value) for the reduction
3832	>	* @param reducer a commutative associative combining function
3833	>	* @return the result of accumulating the given transformation
3834	>	* of all (key, value) pairs
3835	>	* @since 1.8
3836	>	*/
3837	>	public int reduceToInt(long parallelismThreshold,
3838	>	ToIntBiFunction<? super K, ? super V> transformer,
3839	>	int basis,
3840	>	IntBinaryOperator reducer) {
3841	>	if (transformer == null || reducer == null)
3842	>	throw new NullPointerException();
3843	>	return new MapReduceMappingsToIntTask<K,V>
3844	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3845	>	null, transformer, basis, reducer).invoke();
3846	>	}
3847	>
3848	>	/**
3849	>	* Performs the given action for each key.
3850	>	*
3851	>	* @param parallelismThreshold the (estimated) number of elements
3852	>	* needed for this operation to be executed in parallel
3853	>	* @param action the action
3854	>	* @since 1.8
3855	>	*/
3856	>	public void forEachKey(long parallelismThreshold,
3857	>	Consumer<? super K> action) {
3858	>	if (action == null) throw new NullPointerException();
3859	>	new ForEachKeyTask<K,V>
3860	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3861	>	action).invoke();
3862	>	}
3863	>
3864	>	/**
3865	>	* Performs the given action for each non-null transformation
3866	>	* of each key.
3867	>	*
3868	>	* @param parallelismThreshold the (estimated) number of elements
3869	>	* needed for this operation to be executed in parallel
3870	>	* @param transformer a function returning the transformation
3871	>	* for an element, or null if there is no transformation (in
3872	>	* which case the action is not applied)
3873	>	* @param action the action
3874	>	* @param <U> the return type of the transformer
3875	>	* @since 1.8
3876	>	*/
3877	>	public <U> void forEachKey(long parallelismThreshold,
3878	>	Function<? super K, ? extends U> transformer,
3879	>	Consumer<? super U> action) {
3880	>	if (transformer == null || action == null)
3881	>	throw new NullPointerException();
3882	>	new ForEachTransformedKeyTask<K,V,U>
3883	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3884	>	transformer, action).invoke();
3885	>	}
3886	>
3887	>	/**
3888	>	* Returns a non-null result from applying the given search
3889	>	* function on each key, or null if none. Upon success,
3890	>	* further element processing is suppressed and the results of
3891	>	* any other parallel invocations of the search function are
3892	>	* ignored.
3893	>	*
3894	>	* @param parallelismThreshold the (estimated) number of elements
3895	>	* needed for this operation to be executed in parallel
3896	>	* @param searchFunction a function returning a non-null
3897	>	* result on success, else null
3898	>	* @param <U> the return type of the search function
3899	>	* @return a non-null result from applying the given search
3900	>	* function on each key, or null if none
3901	>	* @since 1.8
3902	>	*/
3903	>	public <U> U searchKeys(long parallelismThreshold,
3904	>	Function<? super K, ? extends U> searchFunction) {
3905	>	if (searchFunction == null) throw new NullPointerException();
3906	>	return new SearchKeysTask<K,V,U>
3907	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3908	>	searchFunction, new AtomicReference<U>()).invoke();
3909	>	}
3910	>
3911	>	/**
3912	>	* Returns the result of accumulating all keys using the given
3913	>	* reducer to combine values, or null if none.
3914	>	*
3915	>	* @param parallelismThreshold the (estimated) number of elements
3916	>	* needed for this operation to be executed in parallel
3917	>	* @param reducer a commutative associative combining function
3918	>	* @return the result of accumulating all keys using the given
3919	>	* reducer to combine values, or null if none
3920	>	* @since 1.8
3921	>	*/
3922	>	public K reduceKeys(long parallelismThreshold,
3923	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3924	>	if (reducer == null) throw new NullPointerException();
3925	>	return new ReduceKeysTask<K,V>
3926	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3927	>	null, reducer).invoke();
3928	>	}
3929	>
3930	>	/**
3931	>	* Returns the result of accumulating the given transformation
3932	>	* of all keys using the given reducer to combine values, or
3933	>	* null if none.
3934	>	*
3935	>	* @param parallelismThreshold the (estimated) number of elements
3936	>	* needed for this operation to be executed in parallel
3937	>	* @param transformer a function returning the transformation
3938	>	* for an element, or null if there is no transformation (in
3939	>	* which case it is not combined)
3940	>	* @param reducer a commutative associative combining function
3941	>	* @param <U> the return type of the transformer
3942	>	* @return the result of accumulating the given transformation
3943	>	* of all keys
3944	>	* @since 1.8
3945	>	*/
3946	>	public <U> U reduceKeys(long parallelismThreshold,
3947	>	Function<? super K, ? extends U> transformer,
3948	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3949	>	if (transformer == null || reducer == null)
3950	>	throw new NullPointerException();
3951	>	return new MapReduceKeysTask<K,V,U>
3952	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3953	>	null, transformer, reducer).invoke();
3954	>	}
3955	>
3956	>	/**
3957	>	* Returns the result of accumulating the given transformation
3958	>	* of all keys using the given reducer to combine values, and
3959	>	* the given basis as an identity value.
3960	>	*
3961	>	* @param parallelismThreshold the (estimated) number of elements
3962	>	* needed for this operation to be executed in parallel
3963	>	* @param transformer a function returning the transformation
3964	>	* for an element
3965	>	* @param basis the identity (initial default value) for the reduction
3966	>	* @param reducer a commutative associative combining function
3967	>	* @return the result of accumulating the given transformation
3968	>	* of all keys
3969	>	* @since 1.8
3970	>	*/
3971	>	public double reduceKeysToDouble(long parallelismThreshold,
3972	>	ToDoubleFunction<? super K> transformer,
3973	>	double basis,
3974	>	DoubleBinaryOperator reducer) {
3975	>	if (transformer == null || reducer == null)
3976	>	throw new NullPointerException();
3977	>	return new MapReduceKeysToDoubleTask<K,V>
3978	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3979	>	null, transformer, basis, reducer).invoke();
3980	>	}
3981	>
3982	>	/**
3983	>	* Returns the result of accumulating the given transformation
3984	>	* of all keys using the given reducer to combine values, and
3985	>	* the given basis as an identity value.
3986	>	*
3987	>	* @param parallelismThreshold the (estimated) number of elements
3988	>	* needed for this operation to be executed in parallel
3989	>	* @param transformer a function returning the transformation
3990	>	* for an element
3991	>	* @param basis the identity (initial default value) for the reduction
3992	>	* @param reducer a commutative associative combining function
3993	>	* @return the result of accumulating the given transformation
3994	>	* of all keys
3995	>	* @since 1.8
3996	>	*/
3997	>	public long reduceKeysToLong(long parallelismThreshold,
3998	>	ToLongFunction<? super K> transformer,
3999	>	long basis,
4000	>	LongBinaryOperator reducer) {
4001	>	if (transformer == null || reducer == null)
4002	>	throw new NullPointerException();
4003	>	return new MapReduceKeysToLongTask<K,V>
4004	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4005	>	null, transformer, basis, reducer).invoke();
4006	>	}
4007	>
4008	>	/**
4009	>	* Returns the result of accumulating the given transformation
4010	>	* of all keys using the given reducer to combine values, and
4011	>	* the given basis as an identity value.
4012	>	*
4013	>	* @param parallelismThreshold the (estimated) number of elements
4014	>	* needed for this operation to be executed in parallel
4015	>	* @param transformer a function returning the transformation
4016	>	* for an element
4017	>	* @param basis the identity (initial default value) for the reduction
4018	>	* @param reducer a commutative associative combining function
4019	>	* @return the result of accumulating the given transformation
4020	>	* of all keys
4021	>	* @since 1.8
4022	>	*/
4023	>	public int reduceKeysToInt(long parallelismThreshold,
4024	>	ToIntFunction<? super K> transformer,
4025	>	int basis,
4026	>	IntBinaryOperator reducer) {
4027	>	if (transformer == null || reducer == null)
4028	>	throw new NullPointerException();
4029	>	return new MapReduceKeysToIntTask<K,V>
4030	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4031	>	null, transformer, basis, reducer).invoke();
4032	>	}
4033	>
4034	>	/**
4035	>	* Performs the given action for each value.
4036	>	*
4037	>	* @param parallelismThreshold the (estimated) number of elements
4038	>	* needed for this operation to be executed in parallel
4039	>	* @param action the action
4040	>	* @since 1.8
4041	>	*/
4042	>	public void forEachValue(long parallelismThreshold,
4043	>	Consumer<? super V> action) {
4044	>	if (action == null)
4045	>	throw new NullPointerException();
4046	>	new ForEachValueTask<K,V>
4047	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4048	>	action).invoke();
4049	>	}
4050	>
4051	>	/**
4052	>	* Performs the given action for each non-null transformation
4053	>	* of each value.
4054	>	*
4055	>	* @param parallelismThreshold the (estimated) number of elements
4056	>	* needed for this operation to be executed in parallel
4057	>	* @param transformer a function returning the transformation
4058	>	* for an element, or null if there is no transformation (in
4059	>	* which case the action is not applied)
4060	>	* @param action the action
4061	>	* @param <U> the return type of the transformer
4062	>	* @since 1.8
4063	>	*/
4064	>	public <U> void forEachValue(long parallelismThreshold,
4065	>	Function<? super V, ? extends U> transformer,
4066	>	Consumer<? super U> action) {
4067	>	if (transformer == null || action == null)
4068	>	throw new NullPointerException();
4069	>	new ForEachTransformedValueTask<K,V,U>
4070	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4071	>	transformer, action).invoke();
4072	>	}
4073	>
4074	>	/**
4075	>	* Returns a non-null result from applying the given search
4076	>	* function on each value, or null if none.  Upon success,
4077	>	* further element processing is suppressed and the results of
4078	>	* any other parallel invocations of the search function are
4079	>	* ignored.
4080	>	*
4081	>	* @param parallelismThreshold the (estimated) number of elements
4082	>	* needed for this operation to be executed in parallel
4083	>	* @param searchFunction a function returning a non-null
4084	>	* result on success, else null
4085	>	* @param <U> the return type of the search function
4086	>	* @return a non-null result from applying the given search
4087	>	* function on each value, or null if none
4088	>	* @since 1.8
4089	>	*/
4090	>	public <U> U searchValues(long parallelismThreshold,
4091	>	Function<? super V, ? extends U> searchFunction) {
4092	>	if (searchFunction == null) throw new NullPointerException();
4093	>	return new SearchValuesTask<K,V,U>
4094	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4095	>	searchFunction, new AtomicReference<U>()).invoke();
4096	>	}
4097	>
4098	>	/**
4099	>	* Returns the result of accumulating all values using the
4100	>	* given reducer to combine values, or null if none.
4101	>	*
4102	>	* @param parallelismThreshold the (estimated) number of elements
4103	>	* needed for this operation to be executed in parallel
4104	>	* @param reducer a commutative associative combining function
4105	>	* @return the result of accumulating all values
4106	>	* @since 1.8
4107	>	*/
4108	>	public V reduceValues(long parallelismThreshold,
4109	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4110	>	if (reducer == null) throw new NullPointerException();
4111	>	return new ReduceValuesTask<K,V>
4112	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4113	>	null, reducer).invoke();
4114	>	}
4115	>
4116	>	/**
4117	>	* Returns the result of accumulating the given transformation
4118	>	* of all values using the given reducer to combine values, or
4119	>	* null if none.
4120	>	*
4121	>	* @param parallelismThreshold the (estimated) number of elements
4122	>	* needed for this operation to be executed in parallel
4123	>	* @param transformer a function returning the transformation
4124	>	* for an element, or null if there is no transformation (in
4125	>	* which case it is not combined)
4126	>	* @param reducer a commutative associative combining function
4127	>	* @param <U> the return type of the transformer
4128	>	* @return the result of accumulating the given transformation
4129	>	* of all values
4130	>	* @since 1.8
4131	>	*/
4132	>	public <U> U reduceValues(long parallelismThreshold,
4133	>	Function<? super V, ? extends U> transformer,
4134	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4135	>	if (transformer == null || reducer == null)
4136	>	throw new NullPointerException();
4137	>	return new MapReduceValuesTask<K,V,U>
4138	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4139	>	null, transformer, reducer).invoke();
4140	>	}
4141	>
4142	>	/**
4143	>	* Returns the result of accumulating the given transformation
4144	>	* of all values using the given reducer to combine values,
4145	>	* and the given basis as an identity value.
4146	>	*
4147	>	* @param parallelismThreshold the (estimated) number of elements
4148	>	* needed for this operation to be executed in parallel
4149	>	* @param transformer a function returning the transformation
4150	>	* for an element
4151	>	* @param basis the identity (initial default value) for the reduction
4152	>	* @param reducer a commutative associative combining function
4153	>	* @return the result of accumulating the given transformation
4154	>	* of all values
4155	>	* @since 1.8
4156	>	*/
4157	>	public double reduceValuesToDouble(long parallelismThreshold,
4158	>	ToDoubleFunction<? super V> transformer,
4159	>	double basis,
4160	>	DoubleBinaryOperator reducer) {
4161	>	if (transformer == null || reducer == null)
4162	>	throw new NullPointerException();
4163	>	return new MapReduceValuesToDoubleTask<K,V>
4164	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4165	>	null, transformer, basis, reducer).invoke();
4166	>	}
4167	>
4168	>	/**
4169	>	* Returns the result of accumulating the given transformation
4170	>	* of all values using the given reducer to combine values,
4171	>	* and the given basis as an identity value.
4172	>	*
4173	>	* @param parallelismThreshold the (estimated) number of elements
4174	>	* needed for this operation to be executed in parallel
4175	>	* @param transformer a function returning the transformation
4176	>	* for an element
4177	>	* @param basis the identity (initial default value) for the reduction
4178	>	* @param reducer a commutative associative combining function
4179	>	* @return the result of accumulating the given transformation
4180	>	* of all values
4181	>	* @since 1.8
4182	>	*/
4183	>	public long reduceValuesToLong(long parallelismThreshold,
4184	>	ToLongFunction<? super V> transformer,
4185	>	long basis,
4186	>	LongBinaryOperator reducer) {
4187	>	if (transformer == null || reducer == null)
4188	>	throw new NullPointerException();
4189	>	return new MapReduceValuesToLongTask<K,V>
4190	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4191	>	null, transformer, basis, reducer).invoke();
4192	>	}
4193	>
4194	>	/**
4195	>	* Returns the result of accumulating the given transformation
4196	>	* of all values using the given reducer to combine values,
4197	>	* and the given basis as an identity value.
4198	>	*
4199	>	* @param parallelismThreshold the (estimated) number of elements
4200	>	* needed for this operation to be executed in parallel
4201	>	* @param transformer a function returning the transformation
4202	>	* for an element
4203	>	* @param basis the identity (initial default value) for the reduction
4204	>	* @param reducer a commutative associative combining function
4205	>	* @return the result of accumulating the given transformation
4206	>	* of all values
4207	>	* @since 1.8
4208	>	*/
4209	>	public int reduceValuesToInt(long parallelismThreshold,
4210	>	ToIntFunction<? super V> transformer,
4211	>	int basis,
4212	>	IntBinaryOperator reducer) {
4213	>	if (transformer == null || reducer == null)
4214	>	throw new NullPointerException();
4215	>	return new MapReduceValuesToIntTask<K,V>
4216	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4217	>	null, transformer, basis, reducer).invoke();
4218	>	}
4219	>
4220	>	/**
4221	>	* Performs the given action for each entry.
4222	>	*
4223	>	* @param parallelismThreshold the (estimated) number of elements
4224	>	* needed for this operation to be executed in parallel
4225	>	* @param action the action
4226	>	* @since 1.8
4227	>	*/
4228	>	public void forEachEntry(long parallelismThreshold,
4229	>	Consumer<? super Map.Entry<K,V>> action) {
4230	>	if (action == null) throw new NullPointerException();
4231	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4232	>	action).invoke();
4233	>	}
4234	>
4235	>	/**
4236	>	* Performs the given action for each non-null transformation
4237	>	* of each entry.
4238	>	*
4239	>	* @param parallelismThreshold the (estimated) number of elements
4240	>	* needed for this operation to be executed in parallel
4241	>	* @param transformer a function returning the transformation
4242	>	* for an element, or null if there is no transformation (in
4243	>	* which case the action is not applied)
4244	>	* @param action the action
4245	>	* @param <U> the return type of the transformer
4246	>	* @since 1.8
4247	>	*/
4248	>	public <U> void forEachEntry(long parallelismThreshold,
4249	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4250	>	Consumer<? super U> action) {
4251	>	if (transformer == null || action == null)
4252	>	throw new NullPointerException();
4253	>	new ForEachTransformedEntryTask<K,V,U>
4254	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4255	>	transformer, action).invoke();
4256	>	}
4257	>
4258	>	/**
4259	>	* Returns a non-null result from applying the given search
4260	>	* function on each entry, or null if none.  Upon success,
4261	>	* further element processing is suppressed and the results of
4262	>	* any other parallel invocations of the search function are
4263	>	* ignored.
4264	>	*
4265	>	* @param parallelismThreshold the (estimated) number of elements
4266	>	* needed for this operation to be executed in parallel
4267	>	* @param searchFunction a function returning a non-null
4268	>	* result on success, else null
4269	>	* @param <U> the return type of the search function
4270	>	* @return a non-null result from applying the given search
4271	>	* function on each entry, or null if none
4272	>	* @since 1.8
4273	>	*/
4274	>	public <U> U searchEntries(long parallelismThreshold,
4275	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4276	>	if (searchFunction == null) throw new NullPointerException();
4277	>	return new SearchEntriesTask<K,V,U>
4278	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4279	>	searchFunction, new AtomicReference<U>()).invoke();
4280	>	}
4281	>
4282	>	/**
4283	>	* Returns the result of accumulating all entries using the
4284	>	* given reducer to combine values, or null if none.
4285	>	*
4286	>	* @param parallelismThreshold the (estimated) number of elements
4287	>	* needed for this operation to be executed in parallel
4288	>	* @param reducer a commutative associative combining function
4289	>	* @return the result of accumulating all entries
4290	>	* @since 1.8
4291	>	*/
4292	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4293	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4294	>	if (reducer == null) throw new NullPointerException();
4295	>	return new ReduceEntriesTask<K,V>
4296	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4297	>	null, reducer).invoke();
4298	>	}
4299	>
4300	>	/**
4301	>	* Returns the result of accumulating the given transformation
4302	>	* of all entries using the given reducer to combine values,
4303	>	* or null if none.
4304	>	*
4305	>	* @param parallelismThreshold the (estimated) number of elements
4306	>	* needed for this operation to be executed in parallel
4307	>	* @param transformer a function returning the transformation
4308	>	* for an element, or null if there is no transformation (in
4309	>	* which case it is not combined)
4310	>	* @param reducer a commutative associative combining function
4311	>	* @param <U> the return type of the transformer
4312	>	* @return the result of accumulating the given transformation
4313	>	* of all entries
4314	>	* @since 1.8
4315	>	*/
4316	>	public <U> U reduceEntries(long parallelismThreshold,
4317	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4318	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4319	>	if (transformer == null || reducer == null)
4320	>	throw new NullPointerException();
4321	>	return new MapReduceEntriesTask<K,V,U>
4322	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4323	>	null, transformer, reducer).invoke();
4324	>	}
4325	>
4326	>	/**
4327	>	* Returns the result of accumulating the given transformation
4328	>	* of all entries using the given reducer to combine values,
4329	>	* and the given basis as an identity value.
4330	>	*
4331	>	* @param parallelismThreshold the (estimated) number of elements
4332	>	* needed for this operation to be executed in parallel
4333	>	* @param transformer a function returning the transformation
4334	>	* for an element
4335	>	* @param basis the identity (initial default value) for the reduction
4336	>	* @param reducer a commutative associative combining function
4337	>	* @return the result of accumulating the given transformation
4338	>	* of all entries
4339	>	* @since 1.8
4340	>	*/
4341	>	public double reduceEntriesToDouble(long parallelismThreshold,
4342	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4343	>	double basis,
4344	>	DoubleBinaryOperator reducer) {
4345	>	if (transformer == null || reducer == null)
4346	>	throw new NullPointerException();
4347	>	return new MapReduceEntriesToDoubleTask<K,V>
4348	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4349	>	null, transformer, basis, reducer).invoke();
4350	>	}
4351	>
4352	>	/**
4353	>	* Returns the result of accumulating the given transformation
4354	>	* of all entries using the given reducer to combine values,
4355	>	* and the given basis as an identity value.
4356	>	*
4357	>	* @param parallelismThreshold the (estimated) number of elements
4358	>	* needed for this operation to be executed in parallel
4359	>	* @param transformer a function returning the transformation
4360	>	* for an element
4361	>	* @param basis the identity (initial default value) for the reduction
4362	>	* @param reducer a commutative associative combining function
4363	>	* @return the result of accumulating the given transformation
4364	>	* of all entries
4365	>	* @since 1.8
4366	>	*/
4367	>	public long reduceEntriesToLong(long parallelismThreshold,
4368	>	ToLongFunction<Map.Entry<K,V>> transformer,
4369	>	long basis,
4370	>	LongBinaryOperator reducer) {
4371	>	if (transformer == null || reducer == null)
4372	>	throw new NullPointerException();
4373	>	return new MapReduceEntriesToLongTask<K,V>
4374	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4375	>	null, transformer, basis, reducer).invoke();
4376	>	}
4377	>
4378	>	/**
4379	>	* Returns the result of accumulating the given transformation
4380	>	* of all entries using the given reducer to combine values,
4381	>	* and the given basis as an identity value.
4382	>	*
4383	>	* @param parallelismThreshold the (estimated) number of elements
4384	>	* needed for this operation to be executed in parallel
4385	>	* @param transformer a function returning the transformation
4386	>	* for an element
4387	>	* @param basis the identity (initial default value) for the reduction
4388	>	* @param reducer a commutative associative combining function
4389	>	* @return the result of accumulating the given transformation
4390	>	* of all entries
4391	>	* @since 1.8
4392	>	*/
4393	>	public int reduceEntriesToInt(long parallelismThreshold,
4394	>	ToIntFunction<Map.Entry<K,V>> transformer,
4395	>	int basis,
4396	>	IntBinaryOperator reducer) {
4397	>	if (transformer == null || reducer == null)
4398	>	throw new NullPointerException();
4399	>	return new MapReduceEntriesToIntTask<K,V>
4400	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4401	>	null, transformer, basis, reducer).invoke();
4402	>	}
4403	>
4404	>
4405	>	/* ----------------Views -------------- */
4406	>
4407	>	/**
4408	>	* Base class for views.
4409	>	*/
4410	>	abstract static class CollectionView<K,V,E>
4411	>	implements Collection<E>, java.io.Serializable {
4412	>	private static final long serialVersionUID = 7249069246763182397L;
4413	>	final ConcurrentHashMap<K,V> map;
4414	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4415	>
4416	>	/**
4417	>	* Returns the map backing this view.
4418	>	*
4419	>	* @return the map backing this view
4420	>	*/
4421	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4422	>
4423	>	/**
4424	>	* Removes all of the elements from this view, by removing all
4425	>	* the mappings from the map backing this view.
4426	>	*/
4427	>	public final void clear()      { map.clear(); }
4428	>	public final int size()        { return map.size(); }
4429	>	public final boolean isEmpty() { return map.isEmpty(); }
4430	>
4431	>	// implementations below rely on concrete classes supplying these
4432	>	// abstract methods
4433	>	/**
4434	>	* Returns an iterator over the elements in this collection.
4435	>	*
4436	>	* <p>The returned iterator is
4437	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4438	>	*
4439	>	* @return an iterator over the elements in this collection
4440	>	*/
4441	>	public abstract Iterator<E> iterator();
4442	>	public abstract boolean contains(Object o);
4443	>	public abstract boolean remove(Object o);
4444	>
4445	>	private static final String OOME_MSG = "Required array size too large";
4446	>
4447	>	public final Object[] toArray() {
4448	>	long sz = map.mappingCount();
4449	>	if (sz > MAX_ARRAY_SIZE)
4450	>	throw new OutOfMemoryError(OOME_MSG);
4451	>	int n = (int)sz;
4452	>	Object[] r = new Object[n];
4453	>	int i = 0;
4454	>	for (E e : this) {
4455	>	if (i == n) {
4456	>	if (n >= MAX_ARRAY_SIZE)
4457	>	throw new OutOfMemoryError(OOME_MSG);
4458	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4459	>	n = MAX_ARRAY_SIZE;
4460	>	else
4461	>	n += (n >>> 1) + 1;
4462	>	r = Arrays.copyOf(r, n);
4463	>	}
4464	>	r[i++] = e;
4465	>	}
4466	>	return (i == n) ? r : Arrays.copyOf(r, i);
4467	>	}
4468	>
4469	>	@SuppressWarnings("unchecked")
4470	>	public final <T> T[] toArray(T[] a) {
4471	>	long sz = map.mappingCount();
4472	>	if (sz > MAX_ARRAY_SIZE)
4473	>	throw new OutOfMemoryError(OOME_MSG);
4474	>	int m = (int)sz;
4475	>	T[] r = (a.length >= m) ? a :
4476	>	(T[])java.lang.reflect.Array
4477	>	.newInstance(a.getClass().getComponentType(), m);
4478	>	int n = r.length;
4479	>	int i = 0;
4480	>	for (E e : this) {
4481	>	if (i == n) {
4482	>	if (n >= MAX_ARRAY_SIZE)
4483	>	throw new OutOfMemoryError(OOME_MSG);
4484	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4485	>	n = MAX_ARRAY_SIZE;
4486	>	else
4487	>	n += (n >>> 1) + 1;
4488	>	r = Arrays.copyOf(r, n);
4489	>	}
4490	>	r[i++] = (T)e;
4491	>	}
4492	>	if (a == r && i < n) {
4493	>	r[i] = null; // null-terminate
4494	>	return r;
4495	>	}
4496	>	return (i == n) ? r : Arrays.copyOf(r, i);
4497	>	}
4498	>
4499	>	/**
4500	>	* Returns a string representation of this collection.
4501	>	* The string representation consists of the string representations
4502	>	* of the collection's elements in the order they are returned by
4503	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4504	>	* Adjacent elements are separated by the characters {@code ", "}
4505	>	* (comma and space).  Elements are converted to strings as by
4506	>	* {@link String#valueOf(Object)}.
4507	>	*
4508	>	* @return a string representation of this collection
4509	>	*/
4510	>	public final String toString() {
4511	>	StringBuilder sb = new StringBuilder();
4512	>	sb.append('[');
4513	>	Iterator<E> it = iterator();
4514	>	if (it.hasNext()) {
4515	>	for (;;) {
4516	>	Object e = it.next();
4517	>	sb.append(e == this ? "(this Collection)" : e);
4518	>	if (!it.hasNext())
4519	>	break;
4520	>	sb.append(',').append(' ');
4521	>	}
4522	>	}
4523	>	return sb.append(']').toString();
4524	>	}
4525	>
4526	>	public final boolean containsAll(Collection<?> c) {
4527	>	if (c != this) {
4528	>	for (Object e : c) {
4529	>	if (e == null || !contains(e))
4530	>	return false;
4531	>	}
4532	>	}
4533	>	return true;
4534		}
4535	<	public void clear() {
4536	<	ConcurrentHashMap.this.clear();
4535	>
4536	>	public boolean removeAll(Collection<?> c) {
4537	>	if (c == null) throw new NullPointerException();
4538	>	boolean modified = false;
4539	>	// Use (c instanceof Set) as a hint that lookup in c is as
4540	>	// efficient as this view
4541	>	Node<K,V>[] t;
4542	>	if ((t = map.table) == null) {
4543	>	return false;
4544	>	} else if (c instanceof Set<?> && c.size() > t.length) {
4545	>	for (Iterator<?> it = iterator(); it.hasNext(); ) {
4546	>	if (c.contains(it.next())) {
4547	>	it.remove();
4548	>	modified = true;
4549	>	}
4550	>	}
4551	>	} else {
4552	>	for (Object e : c)
4553	>	modified |= remove(e);
4554	>	}
4555	>	return modified;
4556		}
4557	+
4558	+	public final boolean retainAll(Collection<?> c) {
4559	+	if (c == null) throw new NullPointerException();
4560	+	boolean modified = false;
4561	+	for (Iterator<E> it = iterator(); it.hasNext();) {
4562	+	if (!c.contains(it.next())) {
4563	+	it.remove();
4564	+	modified = true;
4565	+	}
4566	+	}
4567	+	return modified;
4568	+	}
4569	+
4570		}
4571
4572	<	final class Values extends AbstractCollection<V> {
4573	<	public Iterator<V> iterator() {
4574	<	return new ValueIterator();
4572	>	/**
4573	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4574	>	* which additions may optionally be enabled by mapping to a
4575	>	* common value.  This class cannot be directly instantiated.
4576	>	* See {@link #keySet() keySet()},
4577	>	* {@link #keySet(Object) keySet(V)},
4578	>	* {@link #newKeySet() newKeySet()},
4579	>	* {@link #newKeySet(int) newKeySet(int)}.
4580	>	*
4581	>	* @since 1.8
4582	>	*/
4583	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4584	>	implements Set<K>, java.io.Serializable {
4585	>	private static final long serialVersionUID = 7249069246763182397L;
4586	>	private final V value;
4587	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4588	>	super(map);
4589	>	this.value = value;
4590		}
4591	<	public int size() {
4592	<	return ConcurrentHashMap.this.size();
4591	>
4592	>	/**
4593	>	* Returns the default mapped value for additions,
4594	>	* or {@code null} if additions are not supported.
4595	>	*
4596	>	* @return the default mapped value for additions, or {@code null}
4597	>	* if not supported
4598	>	*/
4599	>	public V getMappedValue() { return value; }
4600	>
4601	>	/**
4602	>	* {@inheritDoc}
4603	>	* @throws NullPointerException if the specified key is null
4604	>	*/
4605	>	public boolean contains(Object o) { return map.containsKey(o); }
4606	>
4607	>	/**
4608	>	* Removes the key from this map view, by removing the key (and its
4609	>	* corresponding value) from the backing map.  This method does
4610	>	* nothing if the key is not in the map.
4611	>	*
4612	>	* @param  o the key to be removed from the backing map
4613	>	* @return {@code true} if the backing map contained the specified key
4614	>	* @throws NullPointerException if the specified key is null
4615	>	*/
4616	>	public boolean remove(Object o) { return map.remove(o) != null; }
4617	>
4618	>	/**
4619	>	* @return an iterator over the keys of the backing map
4620	>	*/
4621	>	public Iterator<K> iterator() {
4622	>	Node<K,V>[] t;
4623	>	ConcurrentHashMap<K,V> m = map;
4624	>	int f = (t = m.table) == null ? 0 : t.length;
4625	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4626		}
4627	<	public boolean isEmpty() {
4628	<	return ConcurrentHashMap.this.isEmpty();
4627	>
4628	>	/**
4629	>	* Adds the specified key to this set view by mapping the key to
4630	>	* the default mapped value in the backing map, if defined.
4631	>	*
4632	>	* @param e key to be added
4633	>	* @return {@code true} if this set changed as a result of the call
4634	>	* @throws NullPointerException if the specified key is null
4635	>	* @throws UnsupportedOperationException if no default mapped value
4636	>	* for additions was provided
4637	>	*/
4638	>	public boolean add(K e) {
4639	>	V v;
4640	>	if ((v = value) == null)
4641	>	throw new UnsupportedOperationException();
4642	>	return map.putVal(e, v, true) == null;
4643		}
4644	<	public boolean contains(Object o) {
4645	<	return ConcurrentHashMap.this.containsValue(o);
4644	>
4645	>	/**
4646	>	* Adds all of the elements in the specified collection to this set,
4647	>	* as if by calling {@link #add} on each one.
4648	>	*
4649	>	* @param c the elements to be inserted into this set
4650	>	* @return {@code true} if this set changed as a result of the call
4651	>	* @throws NullPointerException if the collection or any of its
4652	>	* elements are {@code null}
4653	>	* @throws UnsupportedOperationException if no default mapped value
4654	>	* for additions was provided
4655	>	*/
4656	>	public boolean addAll(Collection<? extends K> c) {
4657	>	boolean added = false;
4658	>	V v;
4659	>	if ((v = value) == null)
4660	>	throw new UnsupportedOperationException();
4661	>	for (K e : c) {
4662	>	if (map.putVal(e, v, true) == null)
4663	>	added = true;
4664	>	}
4665	>	return added;
4666		}
4667	<	public void clear() {
4668	<	ConcurrentHashMap.this.clear();
4667	>
4668	>	public int hashCode() {
4669	>	int h = 0;
4670	>	for (K e : this)
4671	>	h += e.hashCode();
4672	>	return h;
4673	>	}
4674	>
4675	>	public boolean equals(Object o) {
4676	>	Set<?> c;
4677	>	return ((o instanceof Set) &&
4678	>	((c = (Set<?>)o) == this ||
4679	>	(containsAll(c) && c.containsAll(this))));
4680	>	}
4681	>
4682	>	public Spliterator<K> spliterator() {
4683	>	Node<K,V>[] t;
4684	>	ConcurrentHashMap<K,V> m = map;
4685	>	long n = m.sumCount();
4686	>	int f = (t = m.table) == null ? 0 : t.length;
4687	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4688	>	}
4689	>
4690	>	public void forEach(Consumer<? super K> action) {
4691	>	if (action == null) throw new NullPointerException();
4692	>	Node<K,V>[] t;
4693	>	if ((t = map.table) != null) {
4694	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4695	>	for (Node<K,V> p; (p = it.advance()) != null; )
4696	>	action.accept(p.key);
4697	>	}
4698		}
4699		}
4700
4701	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4702	<	public Iterator<Map.Entry<K,V>> iterator() {
4703	<	return new EntryIterator();
4701	>	/**
4702	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4703	>	* values, in which additions are disabled. This class cannot be
4704	>	* directly instantiated. See {@link #values()}.
4705	>	*/
4706	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4707	>	implements Collection<V>, java.io.Serializable {
4708	>	private static final long serialVersionUID = 2249069246763182397L;
4709	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4710	>	public final boolean contains(Object o) {
4711	>	return map.containsValue(o);
4712		}
4713	+
4714	+	public final boolean remove(Object o) {
4715	+	if (o != null) {
4716	+	for (Iterator<V> it = iterator(); it.hasNext();) {
4717	+	if (o.equals(it.next())) {
4718	+	it.remove();
4719	+	return true;
4720	+	}
4721	+	}
4722	+	}
4723	+	return false;
4724	+	}
4725	+
4726	+	public final Iterator<V> iterator() {
4727	+	ConcurrentHashMap<K,V> m = map;
4728	+	Node<K,V>[] t;
4729	+	int f = (t = m.table) == null ? 0 : t.length;
4730	+	return new ValueIterator<K,V>(t, f, 0, f, m);
4731	+	}
4732	+
4733	+	public final boolean add(V e) {
4734	+	throw new UnsupportedOperationException();
4735	+	}
4736	+	public final boolean addAll(Collection<? extends V> c) {
4737	+	throw new UnsupportedOperationException();
4738	+	}
4739	+
4740	+	@Override public boolean removeAll(Collection<?> c) {
4741	+	if (c == null) throw new NullPointerException();
4742	+	boolean modified = false;
4743	+	for (Iterator<V> it = iterator(); it.hasNext();) {
4744	+	if (c.contains(it.next())) {
4745	+	it.remove();
4746	+	modified = true;
4747	+	}
4748	+	}
4749	+	return modified;
4750	+	}
4751	+
4752	+	public boolean removeIf(Predicate<? super V> filter) {
4753	+	return map.removeValueIf(filter);
4754	+	}
4755	+
4756	+	public Spliterator<V> spliterator() {
4757	+	Node<K,V>[] t;
4758	+	ConcurrentHashMap<K,V> m = map;
4759	+	long n = m.sumCount();
4760	+	int f = (t = m.table) == null ? 0 : t.length;
4761	+	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4762	+	}
4763	+
4764	+	public void forEach(Consumer<? super V> action) {
4765	+	if (action == null) throw new NullPointerException();
4766	+	Node<K,V>[] t;
4767	+	if ((t = map.table) != null) {
4768	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4769	+	for (Node<K,V> p; (p = it.advance()) != null; )
4770	+	action.accept(p.val);
4771	+	}
4772	+	}
4773	+	}
4774	+
4775	+	/**
4776	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4777	+	* entries.  This class cannot be directly instantiated. See
4778	+	* {@link #entrySet()}.
4779	+	*/
4780	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4781	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4782	+	private static final long serialVersionUID = 2249069246763182397L;
4783	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4784	+
4785		public boolean contains(Object o) {
4786	<	if (!(o instanceof Map.Entry))
4787	<	return false;
4788	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4789	<	V v = ConcurrentHashMap.this.get(e.getKey());
4790	<	return v != null && v.equals(e.getValue());
4786	>	Object k, v, r; Map.Entry<?,?> e;
4787	>	return ((o instanceof Map.Entry) &&
4788	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4789	>	(r = map.get(k)) != null &&
4790	>	(v = e.getValue()) != null &&
4791	>	(v == r || v.equals(r)));
4792		}
4793	+
4794		public boolean remove(Object o) {
4795	<	if (!(o instanceof Map.Entry))
4796	<	return false;
4797	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4798	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4795	>	Object k, v; Map.Entry<?,?> e;
4796	>	return ((o instanceof Map.Entry) &&
4797	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4798	>	(v = e.getValue()) != null &&
4799	>	map.remove(k, v));
4800		}
4801	<	public int size() {
4802	<	return ConcurrentHashMap.this.size();
4801	>
4802	>	/**
4803	>	* @return an iterator over the entries of the backing map
4804	>	*/
4805	>	public Iterator<Map.Entry<K,V>> iterator() {
4806	>	ConcurrentHashMap<K,V> m = map;
4807	>	Node<K,V>[] t;
4808	>	int f = (t = m.table) == null ? 0 : t.length;
4809	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4810	>	}
4811	>
4812	>	public boolean add(Entry<K,V> e) {
4813	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4814	>	}
4815	>
4816	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4817	>	boolean added = false;
4818	>	for (Entry<K,V> e : c) {
4819	>	if (add(e))
4820	>	added = true;
4821	>	}
4822	>	return added;
4823		}
4824	<	public boolean isEmpty() {
4825	<	return ConcurrentHashMap.this.isEmpty();
4824	>
4825	>	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4826	>	return map.removeEntryIf(filter);
4827		}
4828	<	public void clear() {
4829	<	ConcurrentHashMap.this.clear();
4828	>
4829	>	public final int hashCode() {
4830	>	int h = 0;
4831	>	Node<K,V>[] t;
4832	>	if ((t = map.table) != null) {
4833	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4834	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4835	>	h += p.hashCode();
4836	>	}
4837	>	}
4838	>	return h;
4839		}
4840	+
4841	+	public final boolean equals(Object o) {
4842	+	Set<?> c;
4843	+	return ((o instanceof Set) &&
4844	+	((c = (Set<?>)o) == this ||
4845	+	(containsAll(c) && c.containsAll(this))));
4846	+	}
4847	+
4848	+	public Spliterator<Map.Entry<K,V>> spliterator() {
4849	+	Node<K,V>[] t;
4850	+	ConcurrentHashMap<K,V> m = map;
4851	+	long n = m.sumCount();
4852	+	int f = (t = m.table) == null ? 0 : t.length;
4853	+	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4854	+	}
4855	+
4856	+	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4857	+	if (action == null) throw new NullPointerException();
4858	+	Node<K,V>[] t;
4859	+	if ((t = map.table) != null) {
4860	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4861	+	for (Node<K,V> p; (p = it.advance()) != null; )
4862	+	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4863	+	}
4864	+	}
4865	+
4866		}
4867
4868	<	/* ---------------- Serialization Support -------------- */
4868	>	// -------------------------------------------------------
4869
4870		/**
4871	<	* Save the state of the <tt>ConcurrentHashMap</tt> instance to a
4872	<	* stream (i.e., serialize it).
1370	<	* @param s the stream
1371	<	* @serialData
1372	<	* the key (Object) and value (Object)
1373	<	* for each key-value mapping, followed by a null pair.
1374	<	* The key-value mappings are emitted in no particular order.
4871	>	* Base class for bulk tasks. Repeats some fields and code from
4872	>	* class Traverser, because we need to subclass CountedCompleter.
4873		*/
4874	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException {
4875	<	// force all segments for serialization compatibility
4876	<	for (int k = 0; k < segments.length; ++k)
4877	<	ensureSegment(k);
4878	<	s.defaultWriteObject();
4879	<
4880	<	final Segment<K,V>[] segments = this.segments;
4881	<	for (int k = 0; k < segments.length; ++k) {
4882	<	Segment<K,V> seg = segmentAt(segments, k);
4883	<	seg.lock();
4884	<	try {
4885	<	HashEntry<K,V>[] tab = seg.table;
4886	<	for (int i = 0; i < tab.length; ++i) {
4887	<	HashEntry<K,V> e;
4888	<	for (e = entryAt(tab, i); e != null; e = e.next) {
4889	<	s.writeObject(e.key);
4890	<	s.writeObject(e.value);
4874	>	@SuppressWarnings("serial")
4875	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4876	>	Node<K,V>[] tab;        // same as Traverser
4877	>	Node<K,V> next;
4878	>	TableStack<K,V> stack, spare;
4879	>	int index;
4880	>	int baseIndex;
4881	>	int baseLimit;
4882	>	final int baseSize;
4883	>	int batch;              // split control
4884	>
4885	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4886	>	super(par);
4887	>	this.batch = b;
4888	>	this.index = this.baseIndex = i;
4889	>	if ((this.tab = t) == null)
4890	>	this.baseSize = this.baseLimit = 0;
4891	>	else if (par == null)
4892	>	this.baseSize = this.baseLimit = t.length;
4893	>	else {
4894	>	this.baseLimit = f;
4895	>	this.baseSize = par.baseSize;
4896	>	}
4897	>	}
4898	>
4899	>	/**
4900	>	* Same as Traverser version.
4901	>	*/
4902	>	final Node<K,V> advance() {
4903	>	Node<K,V> e;
4904	>	if ((e = next) != null)
4905	>	e = e.next;
4906	>	for (;;) {
4907	>	Node<K,V>[] t; int i, n;
4908	>	if (e != null)
4909	>	return next = e;
4910	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4911	>	(n = t.length) <= (i = index) || i < 0)
4912	>	return next = null;
4913	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4914	>	if (e instanceof ForwardingNode) {
4915	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4916	>	e = null;
4917	>	pushState(t, i, n);
4918	>	continue;
4919		}
4920	+	else if (e instanceof TreeBin)
4921	+	e = ((TreeBin<K,V>)e).first;
4922	+	else
4923	+	e = null;
4924		}
4925	<	} finally {
4926	<	seg.unlock();
4925	>	if (stack != null)
4926	>	recoverState(n);
4927	>	else if ((index = i + baseSize) >= n)
4928	>	index = ++baseIndex;
4929		}
4930		}
4931	<	s.writeObject(null);
4932	<	s.writeObject(null);
4931	>
4932	>	private void pushState(Node<K,V>[] t, int i, int n) {
4933	>	TableStack<K,V> s = spare;
4934	>	if (s != null)
4935	>	spare = s.next;
4936	>	else
4937	>	s = new TableStack<K,V>();
4938	>	s.tab = t;
4939	>	s.length = n;
4940	>	s.index = i;
4941	>	s.next = stack;
4942	>	stack = s;
4943	>	}
4944	>
4945	>	private void recoverState(int n) {
4946	>	TableStack<K,V> s; int len;
4947	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4948	>	n = len;
4949	>	index = s.index;
4950	>	tab = s.tab;
4951	>	s.tab = null;
4952	>	TableStack<K,V> next = s.next;
4953	>	s.next = spare; // save for reuse
4954	>	stack = next;
4955	>	spare = s;
4956	>	}
4957	>	if (s == null && (index += baseSize) >= n)
4958	>	index = ++baseIndex;
4959	>	}
4960		}
4961
4962	<	/**
4963	<	* Reconstitute the <tt>ConcurrentHashMap</tt> instance from a
4964	<	* stream (i.e., deserialize it).
4965	<	* @param s the stream
4966	<	*/
4967	<	@SuppressWarnings("unchecked")
4968	<	private void readObject(java.io.ObjectInputStream s)
4969	<	throws IOException, ClassNotFoundException {
4970	<	s.defaultReadObject();
4962	>	/*
4963	>	* Task classes. Coded in a regular but ugly format/style to
4964	>	* simplify checks that each variant differs in the right way from
4965	>	* others. The null screenings exist because compilers cannot tell
4966	>	* that we've already null-checked task arguments, so we force
4967	>	* simplest hoisted bypass to help avoid convoluted traps.
4968	>	*/
4969	>	@SuppressWarnings("serial")
4970	>	static final class ForEachKeyTask<K,V>
4971	>	extends BulkTask<K,V,Void> {
4972	>	final Consumer<? super K> action;
4973	>	ForEachKeyTask
4974	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4975	>	Consumer<? super K> action) {
4976	>	super(p, b, i, f, t);
4977	>	this.action = action;
4978	>	}
4979	>	public final void compute() {
4980	>	final Consumer<? super K> action;
4981	>	if ((action = this.action) != null) {
4982	>	for (int i = baseIndex, f, h; batch > 0 &&
4983	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4984	>	addToPendingCount(1);
4985	>	new ForEachKeyTask<K,V>
4986	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4987	>	action).fork();
4988	>	}
4989	>	for (Node<K,V> p; (p = advance()) != null;)
4990	>	action.accept(p.key);
4991	>	propagateCompletion();
4992	>	}
4993	>	}
4994	>	}
4995
4996	<	// Re-initialize segments to be minimally sized, and let grow.
4997	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
4998	<	final Segment<K,V>[] segments = this.segments;
4999	<	for (int k = 0; k < segments.length; ++k) {
5000	<	Segment<K,V> seg = segments[k];
5001	<	if (seg != null) {
5002	<	seg.threshold = (int)(cap * seg.loadFactor);
5003	<	seg.table = (HashEntry<K,V>[]) new HashEntry[cap];
4996	>	@SuppressWarnings("serial")
4997	>	static final class ForEachValueTask<K,V>
4998	>	extends BulkTask<K,V,Void> {
4999	>	final Consumer<? super V> action;
5000	>	ForEachValueTask
5001	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5002	>	Consumer<? super V> action) {
5003	>	super(p, b, i, f, t);
5004	>	this.action = action;
5005	>	}
5006	>	public final void compute() {
5007	>	final Consumer<? super V> action;
5008	>	if ((action = this.action) != null) {
5009	>	for (int i = baseIndex, f, h; batch > 0 &&
5010	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5011	>	addToPendingCount(1);
5012	>	new ForEachValueTask<K,V>
5013	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5014	>	action).fork();
5015	>	}
5016	>	for (Node<K,V> p; (p = advance()) != null;)
5017	>	action.accept(p.val);
5018	>	propagateCompletion();
5019		}
5020		}
5021	+	}
5022
5023	<	// Read the keys and values, and put the mappings in the table
5024	<	for (;;) {
5025	<	K key = (K) s.readObject();
5026	<	V value = (V) s.readObject();
5027	<	if (key == null)
5028	<	break;
5029	<	put(key, value);
5023	>	@SuppressWarnings("serial")
5024	>	static final class ForEachEntryTask<K,V>
5025	>	extends BulkTask<K,V,Void> {
5026	>	final Consumer<? super Entry<K,V>> action;
5027	>	ForEachEntryTask
5028	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5029	>	Consumer<? super Entry<K,V>> action) {
5030	>	super(p, b, i, f, t);
5031	>	this.action = action;
5032	>	}
5033	>	public final void compute() {
5034	>	final Consumer<? super Entry<K,V>> action;
5035	>	if ((action = this.action) != null) {
5036	>	for (int i = baseIndex, f, h; batch > 0 &&
5037	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5038	>	addToPendingCount(1);
5039	>	new ForEachEntryTask<K,V>
5040	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5041	>	action).fork();
5042	>	}
5043	>	for (Node<K,V> p; (p = advance()) != null; )
5044	>	action.accept(p);
5045	>	propagateCompletion();
5046	>	}
5047	>	}
5048	>	}
5049	>
5050	>	@SuppressWarnings("serial")
5051	>	static final class ForEachMappingTask<K,V>
5052	>	extends BulkTask<K,V,Void> {
5053	>	final BiConsumer<? super K, ? super V> action;
5054	>	ForEachMappingTask
5055	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5056	>	BiConsumer<? super K,? super V> action) {
5057	>	super(p, b, i, f, t);
5058	>	this.action = action;
5059	>	}
5060	>	public final void compute() {
5061	>	final BiConsumer<? super K, ? super V> action;
5062	>	if ((action = this.action) != null) {
5063	>	for (int i = baseIndex, f, h; batch > 0 &&
5064	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5065	>	addToPendingCount(1);
5066	>	new ForEachMappingTask<K,V>
5067	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5068	>	action).fork();
5069	>	}
5070	>	for (Node<K,V> p; (p = advance()) != null; )
5071	>	action.accept(p.key, p.val);
5072	>	propagateCompletion();
5073	>	}
5074	>	}
5075	>	}
5076	>
5077	>	@SuppressWarnings("serial")
5078	>	static final class ForEachTransformedKeyTask<K,V,U>
5079	>	extends BulkTask<K,V,Void> {
5080	>	final Function<? super K, ? extends U> transformer;
5081	>	final Consumer<? super U> action;
5082	>	ForEachTransformedKeyTask
5083	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5084	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5085	>	super(p, b, i, f, t);
5086	>	this.transformer = transformer; this.action = action;
5087	>	}
5088	>	public final void compute() {
5089	>	final Function<? super K, ? extends U> transformer;
5090	>	final Consumer<? super U> action;
5091	>	if ((transformer = this.transformer) != null &&
5092	>	(action = this.action) != null) {
5093	>	for (int i = baseIndex, f, h; batch > 0 &&
5094	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5095	>	addToPendingCount(1);
5096	>	new ForEachTransformedKeyTask<K,V,U>
5097	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5098	>	transformer, action).fork();
5099	>	}
5100	>	for (Node<K,V> p; (p = advance()) != null; ) {
5101	>	U u;
5102	>	if ((u = transformer.apply(p.key)) != null)
5103	>	action.accept(u);
5104	>	}
5105	>	propagateCompletion();
5106	>	}
5107	>	}
5108	>	}
5109	>
5110	>	@SuppressWarnings("serial")
5111	>	static final class ForEachTransformedValueTask<K,V,U>
5112	>	extends BulkTask<K,V,Void> {
5113	>	final Function<? super V, ? extends U> transformer;
5114	>	final Consumer<? super U> action;
5115	>	ForEachTransformedValueTask
5116	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5117	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5118	>	super(p, b, i, f, t);
5119	>	this.transformer = transformer; this.action = action;
5120	>	}
5121	>	public final void compute() {
5122	>	final Function<? super V, ? extends U> transformer;
5123	>	final Consumer<? super U> action;
5124	>	if ((transformer = this.transformer) != null &&
5125	>	(action = this.action) != null) {
5126	>	for (int i = baseIndex, f, h; batch > 0 &&
5127	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5128	>	addToPendingCount(1);
5129	>	new ForEachTransformedValueTask<K,V,U>
5130	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5131	>	transformer, action).fork();
5132	>	}
5133	>	for (Node<K,V> p; (p = advance()) != null; ) {
5134	>	U u;
5135	>	if ((u = transformer.apply(p.val)) != null)
5136	>	action.accept(u);
5137	>	}
5138	>	propagateCompletion();
5139	>	}
5140	>	}
5141	>	}
5142	>
5143	>	@SuppressWarnings("serial")
5144	>	static final class ForEachTransformedEntryTask<K,V,U>
5145	>	extends BulkTask<K,V,Void> {
5146	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5147	>	final Consumer<? super U> action;
5148	>	ForEachTransformedEntryTask
5149	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5150	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5151	>	super(p, b, i, f, t);
5152	>	this.transformer = transformer; this.action = action;
5153	>	}
5154	>	public final void compute() {
5155	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5156	>	final Consumer<? super U> action;
5157	>	if ((transformer = this.transformer) != null &&
5158	>	(action = this.action) != null) {
5159	>	for (int i = baseIndex, f, h; batch > 0 &&
5160	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5161	>	addToPendingCount(1);
5162	>	new ForEachTransformedEntryTask<K,V,U>
5163	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5164	>	transformer, action).fork();
5165	>	}
5166	>	for (Node<K,V> p; (p = advance()) != null; ) {
5167	>	U u;
5168	>	if ((u = transformer.apply(p)) != null)
5169	>	action.accept(u);
5170	>	}
5171	>	propagateCompletion();
5172	>	}
5173	>	}
5174	>	}
5175	>
5176	>	@SuppressWarnings("serial")
5177	>	static final class ForEachTransformedMappingTask<K,V,U>
5178	>	extends BulkTask<K,V,Void> {
5179	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5180	>	final Consumer<? super U> action;
5181	>	ForEachTransformedMappingTask
5182	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5183	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5184	>	Consumer<? super U> action) {
5185	>	super(p, b, i, f, t);
5186	>	this.transformer = transformer; this.action = action;
5187	>	}
5188	>	public final void compute() {
5189	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5190	>	final Consumer<? super U> action;
5191	>	if ((transformer = this.transformer) != null &&
5192	>	(action = this.action) != null) {
5193	>	for (int i = baseIndex, f, h; batch > 0 &&
5194	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5195	>	addToPendingCount(1);
5196	>	new ForEachTransformedMappingTask<K,V,U>
5197	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5198	>	transformer, action).fork();
5199	>	}
5200	>	for (Node<K,V> p; (p = advance()) != null; ) {
5201	>	U u;
5202	>	if ((u = transformer.apply(p.key, p.val)) != null)
5203	>	action.accept(u);
5204	>	}
5205	>	propagateCompletion();
5206	>	}
5207	>	}
5208	>	}
5209	>
5210	>	@SuppressWarnings("serial")
5211	>	static final class SearchKeysTask<K,V,U>
5212	>	extends BulkTask<K,V,U> {
5213	>	final Function<? super K, ? extends U> searchFunction;
5214	>	final AtomicReference<U> result;
5215	>	SearchKeysTask
5216	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5217	>	Function<? super K, ? extends U> searchFunction,
5218	>	AtomicReference<U> result) {
5219	>	super(p, b, i, f, t);
5220	>	this.searchFunction = searchFunction; this.result = result;
5221	>	}
5222	>	public final U getRawResult() { return result.get(); }
5223	>	public final void compute() {
5224	>	final Function<? super K, ? extends U> searchFunction;
5225	>	final AtomicReference<U> result;
5226	>	if ((searchFunction = this.searchFunction) != null &&
5227	>	(result = this.result) != null) {
5228	>	for (int i = baseIndex, f, h; batch > 0 &&
5229	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5230	>	if (result.get() != null)
5231	>	return;
5232	>	addToPendingCount(1);
5233	>	new SearchKeysTask<K,V,U>
5234	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5235	>	searchFunction, result).fork();
5236	>	}
5237	>	while (result.get() == null) {
5238	>	U u;
5239	>	Node<K,V> p;
5240	>	if ((p = advance()) == null) {
5241	>	propagateCompletion();
5242	>	break;
5243	>	}
5244	>	if ((u = searchFunction.apply(p.key)) != null) {
5245	>	if (result.compareAndSet(null, u))
5246	>	quietlyCompleteRoot();
5247	>	break;
5248	>	}
5249	>	}
5250	>	}
5251	>	}
5252	>	}
5253	>
5254	>	@SuppressWarnings("serial")
5255	>	static final class SearchValuesTask<K,V,U>
5256	>	extends BulkTask<K,V,U> {
5257	>	final Function<? super V, ? extends U> searchFunction;
5258	>	final AtomicReference<U> result;
5259	>	SearchValuesTask
5260	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5261	>	Function<? super V, ? extends U> searchFunction,
5262	>	AtomicReference<U> result) {
5263	>	super(p, b, i, f, t);
5264	>	this.searchFunction = searchFunction; this.result = result;
5265	>	}
5266	>	public final U getRawResult() { return result.get(); }
5267	>	public final void compute() {
5268	>	final Function<? super V, ? extends U> searchFunction;
5269	>	final AtomicReference<U> result;
5270	>	if ((searchFunction = this.searchFunction) != null &&
5271	>	(result = this.result) != null) {
5272	>	for (int i = baseIndex, f, h; batch > 0 &&
5273	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5274	>	if (result.get() != null)
5275	>	return;
5276	>	addToPendingCount(1);
5277	>	new SearchValuesTask<K,V,U>
5278	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5279	>	searchFunction, result).fork();
5280	>	}
5281	>	while (result.get() == null) {
5282	>	U u;
5283	>	Node<K,V> p;
5284	>	if ((p = advance()) == null) {
5285	>	propagateCompletion();
5286	>	break;
5287	>	}
5288	>	if ((u = searchFunction.apply(p.val)) != null) {
5289	>	if (result.compareAndSet(null, u))
5290	>	quietlyCompleteRoot();
5291	>	break;
5292	>	}
5293	>	}
5294	>	}
5295	>	}
5296	>	}
5297	>
5298	>	@SuppressWarnings("serial")
5299	>	static final class SearchEntriesTask<K,V,U>
5300	>	extends BulkTask<K,V,U> {
5301	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5302	>	final AtomicReference<U> result;
5303	>	SearchEntriesTask
5304	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5305	>	Function<Entry<K,V>, ? extends U> searchFunction,
5306	>	AtomicReference<U> result) {
5307	>	super(p, b, i, f, t);
5308	>	this.searchFunction = searchFunction; this.result = result;
5309	>	}
5310	>	public final U getRawResult() { return result.get(); }
5311	>	public final void compute() {
5312	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5313	>	final AtomicReference<U> result;
5314	>	if ((searchFunction = this.searchFunction) != null &&
5315	>	(result = this.result) != null) {
5316	>	for (int i = baseIndex, f, h; batch > 0 &&
5317	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5318	>	if (result.get() != null)
5319	>	return;
5320	>	addToPendingCount(1);
5321	>	new SearchEntriesTask<K,V,U>
5322	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5323	>	searchFunction, result).fork();
5324	>	}
5325	>	while (result.get() == null) {
5326	>	U u;
5327	>	Node<K,V> p;
5328	>	if ((p = advance()) == null) {
5329	>	propagateCompletion();
5330	>	break;
5331	>	}
5332	>	if ((u = searchFunction.apply(p)) != null) {
5333	>	if (result.compareAndSet(null, u))
5334	>	quietlyCompleteRoot();
5335	>	return;
5336	>	}
5337	>	}
5338	>	}
5339	>	}
5340	>	}
5341	>
5342	>	@SuppressWarnings("serial")
5343	>	static final class SearchMappingsTask<K,V,U>
5344	>	extends BulkTask<K,V,U> {
5345	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5346	>	final AtomicReference<U> result;
5347	>	SearchMappingsTask
5348	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5349	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5350	>	AtomicReference<U> result) {
5351	>	super(p, b, i, f, t);
5352	>	this.searchFunction = searchFunction; this.result = result;
5353	>	}
5354	>	public final U getRawResult() { return result.get(); }
5355	>	public final void compute() {
5356	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5357	>	final AtomicReference<U> result;
5358	>	if ((searchFunction = this.searchFunction) != null &&
5359	>	(result = this.result) != null) {
5360	>	for (int i = baseIndex, f, h; batch > 0 &&
5361	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5362	>	if (result.get() != null)
5363	>	return;
5364	>	addToPendingCount(1);
5365	>	new SearchMappingsTask<K,V,U>
5366	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5367	>	searchFunction, result).fork();
5368	>	}
5369	>	while (result.get() == null) {
5370	>	U u;
5371	>	Node<K,V> p;
5372	>	if ((p = advance()) == null) {
5373	>	propagateCompletion();
5374	>	break;
5375	>	}
5376	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5377	>	if (result.compareAndSet(null, u))
5378	>	quietlyCompleteRoot();
5379	>	break;
5380	>	}
5381	>	}
5382	>	}
5383	>	}
5384	>	}
5385	>
5386	>	@SuppressWarnings("serial")
5387	>	static final class ReduceKeysTask<K,V>
5388	>	extends BulkTask<K,V,K> {
5389	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5390	>	K result;
5391	>	ReduceKeysTask<K,V> rights, nextRight;
5392	>	ReduceKeysTask
5393	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5394	>	ReduceKeysTask<K,V> nextRight,
5395	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5396	>	super(p, b, i, f, t); this.nextRight = nextRight;
5397	>	this.reducer = reducer;
5398	>	}
5399	>	public final K getRawResult() { return result; }
5400	>	public final void compute() {
5401	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5402	>	if ((reducer = this.reducer) != null) {
5403	>	for (int i = baseIndex, f, h; batch > 0 &&
5404	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5405	>	addToPendingCount(1);
5406	>	(rights = new ReduceKeysTask<K,V>
5407	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5408	>	rights, reducer)).fork();
5409	>	}
5410	>	K r = null;
5411	>	for (Node<K,V> p; (p = advance()) != null; ) {
5412	>	K u = p.key;
5413	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5414	>	}
5415	>	result = r;
5416	>	CountedCompleter<?> c;
5417	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5418	>	@SuppressWarnings("unchecked")
5419	>	ReduceKeysTask<K,V>
5420	>	t = (ReduceKeysTask<K,V>)c,
5421	>	s = t.rights;
5422	>	while (s != null) {
5423	>	K tr, sr;
5424	>	if ((sr = s.result) != null)
5425	>	t.result = (((tr = t.result) == null) ? sr :
5426	>	reducer.apply(tr, sr));
5427	>	s = t.rights = s.nextRight;
5428	>	}
5429	>	}
5430	>	}
5431	>	}
5432	>	}
5433	>
5434	>	@SuppressWarnings("serial")
5435	>	static final class ReduceValuesTask<K,V>
5436	>	extends BulkTask<K,V,V> {
5437	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5438	>	V result;
5439	>	ReduceValuesTask<K,V> rights, nextRight;
5440	>	ReduceValuesTask
5441	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5442	>	ReduceValuesTask<K,V> nextRight,
5443	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5444	>	super(p, b, i, f, t); this.nextRight = nextRight;
5445	>	this.reducer = reducer;
5446	>	}
5447	>	public final V getRawResult() { return result; }
5448	>	public final void compute() {
5449	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5450	>	if ((reducer = this.reducer) != null) {
5451	>	for (int i = baseIndex, f, h; batch > 0 &&
5452	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5453	>	addToPendingCount(1);
5454	>	(rights = new ReduceValuesTask<K,V>
5455	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5456	>	rights, reducer)).fork();
5457	>	}
5458	>	V r = null;
5459	>	for (Node<K,V> p; (p = advance()) != null; ) {
5460	>	V v = p.val;
5461	>	r = (r == null) ? v : reducer.apply(r, v);
5462	>	}
5463	>	result = r;
5464	>	CountedCompleter<?> c;
5465	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5466	>	@SuppressWarnings("unchecked")
5467	>	ReduceValuesTask<K,V>
5468	>	t = (ReduceValuesTask<K,V>)c,
5469	>	s = t.rights;
5470	>	while (s != null) {
5471	>	V tr, sr;
5472	>	if ((sr = s.result) != null)
5473	>	t.result = (((tr = t.result) == null) ? sr :
5474	>	reducer.apply(tr, sr));
5475	>	s = t.rights = s.nextRight;
5476	>	}
5477	>	}
5478	>	}
5479	>	}
5480	>	}
5481	>
5482	>	@SuppressWarnings("serial")
5483	>	static final class ReduceEntriesTask<K,V>
5484	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5485	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5486	>	Map.Entry<K,V> result;
5487	>	ReduceEntriesTask<K,V> rights, nextRight;
5488	>	ReduceEntriesTask
5489	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5490	>	ReduceEntriesTask<K,V> nextRight,
5491	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5492	>	super(p, b, i, f, t); this.nextRight = nextRight;
5493	>	this.reducer = reducer;
5494	>	}
5495	>	public final Map.Entry<K,V> getRawResult() { return result; }
5496	>	public final void compute() {
5497	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5498	>	if ((reducer = this.reducer) != null) {
5499	>	for (int i = baseIndex, f, h; batch > 0 &&
5500	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5501	>	addToPendingCount(1);
5502	>	(rights = new ReduceEntriesTask<K,V>
5503	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5504	>	rights, reducer)).fork();
5505	>	}
5506	>	Map.Entry<K,V> r = null;
5507	>	for (Node<K,V> p; (p = advance()) != null; )
5508	>	r = (r == null) ? p : reducer.apply(r, p);
5509	>	result = r;
5510	>	CountedCompleter<?> c;
5511	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5512	>	@SuppressWarnings("unchecked")
5513	>	ReduceEntriesTask<K,V>
5514	>	t = (ReduceEntriesTask<K,V>)c,
5515	>	s = t.rights;
5516	>	while (s != null) {
5517	>	Map.Entry<K,V> tr, sr;
5518	>	if ((sr = s.result) != null)
5519	>	t.result = (((tr = t.result) == null) ? sr :
5520	>	reducer.apply(tr, sr));
5521	>	s = t.rights = s.nextRight;
5522	>	}
5523	>	}
5524	>	}
5525	>	}
5526	>	}
5527	>
5528	>	@SuppressWarnings("serial")
5529	>	static final class MapReduceKeysTask<K,V,U>
5530	>	extends BulkTask<K,V,U> {
5531	>	final Function<? super K, ? extends U> transformer;
5532	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5533	>	U result;
5534	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5535	>	MapReduceKeysTask
5536	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5537	>	MapReduceKeysTask<K,V,U> nextRight,
5538	>	Function<? super K, ? extends U> transformer,
5539	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5540	>	super(p, b, i, f, t); this.nextRight = nextRight;
5541	>	this.transformer = transformer;
5542	>	this.reducer = reducer;
5543	>	}
5544	>	public final U getRawResult() { return result; }
5545	>	public final void compute() {
5546	>	final Function<? super K, ? extends U> transformer;
5547	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5548	>	if ((transformer = this.transformer) != null &&
5549	>	(reducer = this.reducer) != null) {
5550	>	for (int i = baseIndex, f, h; batch > 0 &&
5551	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5552	>	addToPendingCount(1);
5553	>	(rights = new MapReduceKeysTask<K,V,U>
5554	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5555	>	rights, transformer, reducer)).fork();
5556	>	}
5557	>	U r = null;
5558	>	for (Node<K,V> p; (p = advance()) != null; ) {
5559	>	U u;
5560	>	if ((u = transformer.apply(p.key)) != null)
5561	>	r = (r == null) ? u : reducer.apply(r, u);
5562	>	}
5563	>	result = r;
5564	>	CountedCompleter<?> c;
5565	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5566	>	@SuppressWarnings("unchecked")
5567	>	MapReduceKeysTask<K,V,U>
5568	>	t = (MapReduceKeysTask<K,V,U>)c,
5569	>	s = t.rights;
5570	>	while (s != null) {
5571	>	U tr, sr;
5572	>	if ((sr = s.result) != null)
5573	>	t.result = (((tr = t.result) == null) ? sr :
5574	>	reducer.apply(tr, sr));
5575	>	s = t.rights = s.nextRight;
5576	>	}
5577	>	}
5578	>	}
5579	>	}
5580	>	}
5581	>
5582	>	@SuppressWarnings("serial")
5583	>	static final class MapReduceValuesTask<K,V,U>
5584	>	extends BulkTask<K,V,U> {
5585	>	final Function<? super V, ? extends U> transformer;
5586	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5587	>	U result;
5588	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5589	>	MapReduceValuesTask
5590	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5591	>	MapReduceValuesTask<K,V,U> nextRight,
5592	>	Function<? super V, ? extends U> transformer,
5593	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5594	>	super(p, b, i, f, t); this.nextRight = nextRight;
5595	>	this.transformer = transformer;
5596	>	this.reducer = reducer;
5597	>	}
5598	>	public final U getRawResult() { return result; }
5599	>	public final void compute() {
5600	>	final Function<? super V, ? extends U> transformer;
5601	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5602	>	if ((transformer = this.transformer) != null &&
5603	>	(reducer = this.reducer) != null) {
5604	>	for (int i = baseIndex, f, h; batch > 0 &&
5605	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5606	>	addToPendingCount(1);
5607	>	(rights = new MapReduceValuesTask<K,V,U>
5608	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5609	>	rights, transformer, reducer)).fork();
5610	>	}
5611	>	U r = null;
5612	>	for (Node<K,V> p; (p = advance()) != null; ) {
5613	>	U u;
5614	>	if ((u = transformer.apply(p.val)) != null)
5615	>	r = (r == null) ? u : reducer.apply(r, u);
5616	>	}
5617	>	result = r;
5618	>	CountedCompleter<?> c;
5619	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5620	>	@SuppressWarnings("unchecked")
5621	>	MapReduceValuesTask<K,V,U>
5622	>	t = (MapReduceValuesTask<K,V,U>)c,
5623	>	s = t.rights;
5624	>	while (s != null) {
5625	>	U tr, sr;
5626	>	if ((sr = s.result) != null)
5627	>	t.result = (((tr = t.result) == null) ? sr :
5628	>	reducer.apply(tr, sr));
5629	>	s = t.rights = s.nextRight;
5630	>	}
5631	>	}
5632	>	}
5633	>	}
5634	>	}
5635	>
5636	>	@SuppressWarnings("serial")
5637	>	static final class MapReduceEntriesTask<K,V,U>
5638	>	extends BulkTask<K,V,U> {
5639	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5640	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5641	>	U result;
5642	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5643	>	MapReduceEntriesTask
5644	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5645	>	MapReduceEntriesTask<K,V,U> nextRight,
5646	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5647	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5648	>	super(p, b, i, f, t); this.nextRight = nextRight;
5649	>	this.transformer = transformer;
5650	>	this.reducer = reducer;
5651	>	}
5652	>	public final U getRawResult() { return result; }
5653	>	public final void compute() {
5654	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5655	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5656	>	if ((transformer = this.transformer) != null &&
5657	>	(reducer = this.reducer) != null) {
5658	>	for (int i = baseIndex, f, h; batch > 0 &&
5659	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5660	>	addToPendingCount(1);
5661	>	(rights = new MapReduceEntriesTask<K,V,U>
5662	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5663	>	rights, transformer, reducer)).fork();
5664	>	}
5665	>	U r = null;
5666	>	for (Node<K,V> p; (p = advance()) != null; ) {
5667	>	U u;
5668	>	if ((u = transformer.apply(p)) != null)
5669	>	r = (r == null) ? u : reducer.apply(r, u);
5670	>	}
5671	>	result = r;
5672	>	CountedCompleter<?> c;
5673	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5674	>	@SuppressWarnings("unchecked")
5675	>	MapReduceEntriesTask<K,V,U>
5676	>	t = (MapReduceEntriesTask<K,V,U>)c,
5677	>	s = t.rights;
5678	>	while (s != null) {
5679	>	U tr, sr;
5680	>	if ((sr = s.result) != null)
5681	>	t.result = (((tr = t.result) == null) ? sr :
5682	>	reducer.apply(tr, sr));
5683	>	s = t.rights = s.nextRight;
5684	>	}
5685	>	}
5686	>	}
5687	>	}
5688	>	}
5689	>
5690	>	@SuppressWarnings("serial")
5691	>	static final class MapReduceMappingsTask<K,V,U>
5692	>	extends BulkTask<K,V,U> {
5693	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5694	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5695	>	U result;
5696	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5697	>	MapReduceMappingsTask
5698	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5699	>	MapReduceMappingsTask<K,V,U> nextRight,
5700	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5701	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5702	>	super(p, b, i, f, t); this.nextRight = nextRight;
5703	>	this.transformer = transformer;
5704	>	this.reducer = reducer;
5705	>	}
5706	>	public final U getRawResult() { return result; }
5707	>	public final void compute() {
5708	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5709	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5710	>	if ((transformer = this.transformer) != null &&
5711	>	(reducer = this.reducer) != null) {
5712	>	for (int i = baseIndex, f, h; batch > 0 &&
5713	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5714	>	addToPendingCount(1);
5715	>	(rights = new MapReduceMappingsTask<K,V,U>
5716	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5717	>	rights, transformer, reducer)).fork();
5718	>	}
5719	>	U r = null;
5720	>	for (Node<K,V> p; (p = advance()) != null; ) {
5721	>	U u;
5722	>	if ((u = transformer.apply(p.key, p.val)) != null)
5723	>	r = (r == null) ? u : reducer.apply(r, u);
5724	>	}
5725	>	result = r;
5726	>	CountedCompleter<?> c;
5727	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5728	>	@SuppressWarnings("unchecked")
5729	>	MapReduceMappingsTask<K,V,U>
5730	>	t = (MapReduceMappingsTask<K,V,U>)c,
5731	>	s = t.rights;
5732	>	while (s != null) {
5733	>	U tr, sr;
5734	>	if ((sr = s.result) != null)
5735	>	t.result = (((tr = t.result) == null) ? sr :
5736	>	reducer.apply(tr, sr));
5737	>	s = t.rights = s.nextRight;
5738	>	}
5739	>	}
5740	>	}
5741	>	}
5742	>	}
5743	>
5744	>	@SuppressWarnings("serial")
5745	>	static final class MapReduceKeysToDoubleTask<K,V>
5746	>	extends BulkTask<K,V,Double> {
5747	>	final ToDoubleFunction<? super K> transformer;
5748	>	final DoubleBinaryOperator reducer;
5749	>	final double basis;
5750	>	double result;
5751	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5752	>	MapReduceKeysToDoubleTask
5753	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5754	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5755	>	ToDoubleFunction<? super K> transformer,
5756	>	double basis,
5757	>	DoubleBinaryOperator reducer) {
5758	>	super(p, b, i, f, t); this.nextRight = nextRight;
5759	>	this.transformer = transformer;
5760	>	this.basis = basis; this.reducer = reducer;
5761	>	}
5762	>	public final Double getRawResult() { return result; }
5763	>	public final void compute() {
5764	>	final ToDoubleFunction<? super K> transformer;
5765	>	final DoubleBinaryOperator reducer;
5766	>	if ((transformer = this.transformer) != null &&
5767	>	(reducer = this.reducer) != null) {
5768	>	double r = this.basis;
5769	>	for (int i = baseIndex, f, h; batch > 0 &&
5770	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5771	>	addToPendingCount(1);
5772	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5773	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5774	>	rights, transformer, r, reducer)).fork();
5775	>	}
5776	>	for (Node<K,V> p; (p = advance()) != null; )
5777	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5778	>	result = r;
5779	>	CountedCompleter<?> c;
5780	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5781	>	@SuppressWarnings("unchecked")
5782	>	MapReduceKeysToDoubleTask<K,V>
5783	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5784	>	s = t.rights;
5785	>	while (s != null) {
5786	>	t.result = reducer.applyAsDouble(t.result, s.result);
5787	>	s = t.rights = s.nextRight;
5788	>	}
5789	>	}
5790	>	}
5791	>	}
5792	>	}
5793	>
5794	>	@SuppressWarnings("serial")
5795	>	static final class MapReduceValuesToDoubleTask<K,V>
5796	>	extends BulkTask<K,V,Double> {
5797	>	final ToDoubleFunction<? super V> transformer;
5798	>	final DoubleBinaryOperator reducer;
5799	>	final double basis;
5800	>	double result;
5801	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5802	>	MapReduceValuesToDoubleTask
5803	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5804	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5805	>	ToDoubleFunction<? super V> transformer,
5806	>	double basis,
5807	>	DoubleBinaryOperator reducer) {
5808	>	super(p, b, i, f, t); this.nextRight = nextRight;
5809	>	this.transformer = transformer;
5810	>	this.basis = basis; this.reducer = reducer;
5811	>	}
5812	>	public final Double getRawResult() { return result; }
5813	>	public final void compute() {
5814	>	final ToDoubleFunction<? super V> transformer;
5815	>	final DoubleBinaryOperator reducer;
5816	>	if ((transformer = this.transformer) != null &&
5817	>	(reducer = this.reducer) != null) {
5818	>	double r = this.basis;
5819	>	for (int i = baseIndex, f, h; batch > 0 &&
5820	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5821	>	addToPendingCount(1);
5822	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5823	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5824	>	rights, transformer, r, reducer)).fork();
5825	>	}
5826	>	for (Node<K,V> p; (p = advance()) != null; )
5827	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5828	>	result = r;
5829	>	CountedCompleter<?> c;
5830	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5831	>	@SuppressWarnings("unchecked")
5832	>	MapReduceValuesToDoubleTask<K,V>
5833	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5834	>	s = t.rights;
5835	>	while (s != null) {
5836	>	t.result = reducer.applyAsDouble(t.result, s.result);
5837	>	s = t.rights = s.nextRight;
5838	>	}
5839	>	}
5840	>	}
5841	>	}
5842	>	}
5843	>
5844	>	@SuppressWarnings("serial")
5845	>	static final class MapReduceEntriesToDoubleTask<K,V>
5846	>	extends BulkTask<K,V,Double> {
5847	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5848	>	final DoubleBinaryOperator reducer;
5849	>	final double basis;
5850	>	double result;
5851	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5852	>	MapReduceEntriesToDoubleTask
5853	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5854	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5855	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5856	>	double basis,
5857	>	DoubleBinaryOperator reducer) {
5858	>	super(p, b, i, f, t); this.nextRight = nextRight;
5859	>	this.transformer = transformer;
5860	>	this.basis = basis; this.reducer = reducer;
5861	>	}
5862	>	public final Double getRawResult() { return result; }
5863	>	public final void compute() {
5864	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5865	>	final DoubleBinaryOperator reducer;
5866	>	if ((transformer = this.transformer) != null &&
5867	>	(reducer = this.reducer) != null) {
5868	>	double r = this.basis;
5869	>	for (int i = baseIndex, f, h; batch > 0 &&
5870	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5871	>	addToPendingCount(1);
5872	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5873	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5874	>	rights, transformer, r, reducer)).fork();
5875	>	}
5876	>	for (Node<K,V> p; (p = advance()) != null; )
5877	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5878	>	result = r;
5879	>	CountedCompleter<?> c;
5880	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5881	>	@SuppressWarnings("unchecked")
5882	>	MapReduceEntriesToDoubleTask<K,V>
5883	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5884	>	s = t.rights;
5885	>	while (s != null) {
5886	>	t.result = reducer.applyAsDouble(t.result, s.result);
5887	>	s = t.rights = s.nextRight;
5888	>	}
5889	>	}
5890	>	}
5891	>	}
5892	>	}
5893	>
5894	>	@SuppressWarnings("serial")
5895	>	static final class MapReduceMappingsToDoubleTask<K,V>
5896	>	extends BulkTask<K,V,Double> {
5897	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5898	>	final DoubleBinaryOperator reducer;
5899	>	final double basis;
5900	>	double result;
5901	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5902	>	MapReduceMappingsToDoubleTask
5903	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5904	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5905	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5906	>	double basis,
5907	>	DoubleBinaryOperator reducer) {
5908	>	super(p, b, i, f, t); this.nextRight = nextRight;
5909	>	this.transformer = transformer;
5910	>	this.basis = basis; this.reducer = reducer;
5911	>	}
5912	>	public final Double getRawResult() { return result; }
5913	>	public final void compute() {
5914	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5915	>	final DoubleBinaryOperator reducer;
5916	>	if ((transformer = this.transformer) != null &&
5917	>	(reducer = this.reducer) != null) {
5918	>	double r = this.basis;
5919	>	for (int i = baseIndex, f, h; batch > 0 &&
5920	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5921	>	addToPendingCount(1);
5922	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5923	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5924	>	rights, transformer, r, reducer)).fork();
5925	>	}
5926	>	for (Node<K,V> p; (p = advance()) != null; )
5927	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5928	>	result = r;
5929	>	CountedCompleter<?> c;
5930	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5931	>	@SuppressWarnings("unchecked")
5932	>	MapReduceMappingsToDoubleTask<K,V>
5933	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5934	>	s = t.rights;
5935	>	while (s != null) {
5936	>	t.result = reducer.applyAsDouble(t.result, s.result);
5937	>	s = t.rights = s.nextRight;
5938	>	}
5939	>	}
5940	>	}
5941	>	}
5942	>	}
5943	>
5944	>	@SuppressWarnings("serial")
5945	>	static final class MapReduceKeysToLongTask<K,V>
5946	>	extends BulkTask<K,V,Long> {
5947	>	final ToLongFunction<? super K> transformer;
5948	>	final LongBinaryOperator reducer;
5949	>	final long basis;
5950	>	long result;
5951	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5952	>	MapReduceKeysToLongTask
5953	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5954	>	MapReduceKeysToLongTask<K,V> nextRight,
5955	>	ToLongFunction<? super K> transformer,
5956	>	long basis,
5957	>	LongBinaryOperator reducer) {
5958	>	super(p, b, i, f, t); this.nextRight = nextRight;
5959	>	this.transformer = transformer;
5960	>	this.basis = basis; this.reducer = reducer;
5961	>	}
5962	>	public final Long getRawResult() { return result; }
5963	>	public final void compute() {
5964	>	final ToLongFunction<? super K> transformer;
5965	>	final LongBinaryOperator reducer;
5966	>	if ((transformer = this.transformer) != null &&
5967	>	(reducer = this.reducer) != null) {
5968	>	long r = this.basis;
5969	>	for (int i = baseIndex, f, h; batch > 0 &&
5970	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5971	>	addToPendingCount(1);
5972	>	(rights = new MapReduceKeysToLongTask<K,V>
5973	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5974	>	rights, transformer, r, reducer)).fork();
5975	>	}
5976	>	for (Node<K,V> p; (p = advance()) != null; )
5977	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5978	>	result = r;
5979	>	CountedCompleter<?> c;
5980	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5981	>	@SuppressWarnings("unchecked")
5982	>	MapReduceKeysToLongTask<K,V>
5983	>	t = (MapReduceKeysToLongTask<K,V>)c,
5984	>	s = t.rights;
5985	>	while (s != null) {
5986	>	t.result = reducer.applyAsLong(t.result, s.result);
5987	>	s = t.rights = s.nextRight;
5988	>	}
5989	>	}
5990	>	}
5991	>	}
5992	>	}
5993	>
5994	>	@SuppressWarnings("serial")
5995	>	static final class MapReduceValuesToLongTask<K,V>
5996	>	extends BulkTask<K,V,Long> {
5997	>	final ToLongFunction<? super V> transformer;
5998	>	final LongBinaryOperator reducer;
5999	>	final long basis;
6000	>	long result;
6001	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
6002	>	MapReduceValuesToLongTask
6003	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6004	>	MapReduceValuesToLongTask<K,V> nextRight,
6005	>	ToLongFunction<? super V> transformer,
6006	>	long basis,
6007	>	LongBinaryOperator reducer) {
6008	>	super(p, b, i, f, t); this.nextRight = nextRight;
6009	>	this.transformer = transformer;
6010	>	this.basis = basis; this.reducer = reducer;
6011	>	}
6012	>	public final Long getRawResult() { return result; }
6013	>	public final void compute() {
6014	>	final ToLongFunction<? super V> transformer;
6015	>	final LongBinaryOperator reducer;
6016	>	if ((transformer = this.transformer) != null &&
6017	>	(reducer = this.reducer) != null) {
6018	>	long r = this.basis;
6019	>	for (int i = baseIndex, f, h; batch > 0 &&
6020	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6021	>	addToPendingCount(1);
6022	>	(rights = new MapReduceValuesToLongTask<K,V>
6023	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6024	>	rights, transformer, r, reducer)).fork();
6025	>	}
6026	>	for (Node<K,V> p; (p = advance()) != null; )
6027	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
6028	>	result = r;
6029	>	CountedCompleter<?> c;
6030	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6031	>	@SuppressWarnings("unchecked")
6032	>	MapReduceValuesToLongTask<K,V>
6033	>	t = (MapReduceValuesToLongTask<K,V>)c,
6034	>	s = t.rights;
6035	>	while (s != null) {
6036	>	t.result = reducer.applyAsLong(t.result, s.result);
6037	>	s = t.rights = s.nextRight;
6038	>	}
6039	>	}
6040	>	}
6041	>	}
6042	>	}
6043	>
6044	>	@SuppressWarnings("serial")
6045	>	static final class MapReduceEntriesToLongTask<K,V>
6046	>	extends BulkTask<K,V,Long> {
6047	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6048	>	final LongBinaryOperator reducer;
6049	>	final long basis;
6050	>	long result;
6051	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6052	>	MapReduceEntriesToLongTask
6053	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6054	>	MapReduceEntriesToLongTask<K,V> nextRight,
6055	>	ToLongFunction<Map.Entry<K,V>> transformer,
6056	>	long basis,
6057	>	LongBinaryOperator reducer) {
6058	>	super(p, b, i, f, t); this.nextRight = nextRight;
6059	>	this.transformer = transformer;
6060	>	this.basis = basis; this.reducer = reducer;
6061	>	}
6062	>	public final Long getRawResult() { return result; }
6063	>	public final void compute() {
6064	>	final ToLongFunction<Map.Entry<K,V>> transformer;
6065	>	final LongBinaryOperator reducer;
6066	>	if ((transformer = this.transformer) != null &&
6067	>	(reducer = this.reducer) != null) {
6068	>	long r = this.basis;
6069	>	for (int i = baseIndex, f, h; batch > 0 &&
6070	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6071	>	addToPendingCount(1);
6072	>	(rights = new MapReduceEntriesToLongTask<K,V>
6073	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6074	>	rights, transformer, r, reducer)).fork();
6075	>	}
6076	>	for (Node<K,V> p; (p = advance()) != null; )
6077	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6078	>	result = r;
6079	>	CountedCompleter<?> c;
6080	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6081	>	@SuppressWarnings("unchecked")
6082	>	MapReduceEntriesToLongTask<K,V>
6083	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6084	>	s = t.rights;
6085	>	while (s != null) {
6086	>	t.result = reducer.applyAsLong(t.result, s.result);
6087	>	s = t.rights = s.nextRight;
6088	>	}
6089	>	}
6090	>	}
6091	>	}
6092	>	}
6093	>
6094	>	@SuppressWarnings("serial")
6095	>	static final class MapReduceMappingsToLongTask<K,V>
6096	>	extends BulkTask<K,V,Long> {
6097	>	final ToLongBiFunction<? super K, ? super V> transformer;
6098	>	final LongBinaryOperator reducer;
6099	>	final long basis;
6100	>	long result;
6101	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6102	>	MapReduceMappingsToLongTask
6103	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6104	>	MapReduceMappingsToLongTask<K,V> nextRight,
6105	>	ToLongBiFunction<? super K, ? super V> transformer,
6106	>	long basis,
6107	>	LongBinaryOperator reducer) {
6108	>	super(p, b, i, f, t); this.nextRight = nextRight;
6109	>	this.transformer = transformer;
6110	>	this.basis = basis; this.reducer = reducer;
6111	>	}
6112	>	public final Long getRawResult() { return result; }
6113	>	public final void compute() {
6114	>	final ToLongBiFunction<? super K, ? super V> transformer;
6115	>	final LongBinaryOperator reducer;
6116	>	if ((transformer = this.transformer) != null &&
6117	>	(reducer = this.reducer) != null) {
6118	>	long r = this.basis;
6119	>	for (int i = baseIndex, f, h; batch > 0 &&
6120	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6121	>	addToPendingCount(1);
6122	>	(rights = new MapReduceMappingsToLongTask<K,V>
6123	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6124	>	rights, transformer, r, reducer)).fork();
6125	>	}
6126	>	for (Node<K,V> p; (p = advance()) != null; )
6127	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6128	>	result = r;
6129	>	CountedCompleter<?> c;
6130	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6131	>	@SuppressWarnings("unchecked")
6132	>	MapReduceMappingsToLongTask<K,V>
6133	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6134	>	s = t.rights;
6135	>	while (s != null) {
6136	>	t.result = reducer.applyAsLong(t.result, s.result);
6137	>	s = t.rights = s.nextRight;
6138	>	}
6139	>	}
6140	>	}
6141	>	}
6142	>	}
6143	>
6144	>	@SuppressWarnings("serial")
6145	>	static final class MapReduceKeysToIntTask<K,V>
6146	>	extends BulkTask<K,V,Integer> {
6147	>	final ToIntFunction<? super K> transformer;
6148	>	final IntBinaryOperator reducer;
6149	>	final int basis;
6150	>	int result;
6151	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6152	>	MapReduceKeysToIntTask
6153	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6154	>	MapReduceKeysToIntTask<K,V> nextRight,
6155	>	ToIntFunction<? super K> transformer,
6156	>	int basis,
6157	>	IntBinaryOperator reducer) {
6158	>	super(p, b, i, f, t); this.nextRight = nextRight;
6159	>	this.transformer = transformer;
6160	>	this.basis = basis; this.reducer = reducer;
6161	>	}
6162	>	public final Integer getRawResult() { return result; }
6163	>	public final void compute() {
6164	>	final ToIntFunction<? super K> transformer;
6165	>	final IntBinaryOperator reducer;
6166	>	if ((transformer = this.transformer) != null &&
6167	>	(reducer = this.reducer) != null) {
6168	>	int r = this.basis;
6169	>	for (int i = baseIndex, f, h; batch > 0 &&
6170	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6171	>	addToPendingCount(1);
6172	>	(rights = new MapReduceKeysToIntTask<K,V>
6173	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6174	>	rights, transformer, r, reducer)).fork();
6175	>	}
6176	>	for (Node<K,V> p; (p = advance()) != null; )
6177	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6178	>	result = r;
6179	>	CountedCompleter<?> c;
6180	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6181	>	@SuppressWarnings("unchecked")
6182	>	MapReduceKeysToIntTask<K,V>
6183	>	t = (MapReduceKeysToIntTask<K,V>)c,
6184	>	s = t.rights;
6185	>	while (s != null) {
6186	>	t.result = reducer.applyAsInt(t.result, s.result);
6187	>	s = t.rights = s.nextRight;
6188	>	}
6189	>	}
6190	>	}
6191	>	}
6192	>	}
6193	>
6194	>	@SuppressWarnings("serial")
6195	>	static final class MapReduceValuesToIntTask<K,V>
6196	>	extends BulkTask<K,V,Integer> {
6197	>	final ToIntFunction<? super V> transformer;
6198	>	final IntBinaryOperator reducer;
6199	>	final int basis;
6200	>	int result;
6201	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6202	>	MapReduceValuesToIntTask
6203	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6204	>	MapReduceValuesToIntTask<K,V> nextRight,
6205	>	ToIntFunction<? super V> transformer,
6206	>	int basis,
6207	>	IntBinaryOperator reducer) {
6208	>	super(p, b, i, f, t); this.nextRight = nextRight;
6209	>	this.transformer = transformer;
6210	>	this.basis = basis; this.reducer = reducer;
6211	>	}
6212	>	public final Integer getRawResult() { return result; }
6213	>	public final void compute() {
6214	>	final ToIntFunction<? super V> transformer;
6215	>	final IntBinaryOperator reducer;
6216	>	if ((transformer = this.transformer) != null &&
6217	>	(reducer = this.reducer) != null) {
6218	>	int r = this.basis;
6219	>	for (int i = baseIndex, f, h; batch > 0 &&
6220	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6221	>	addToPendingCount(1);
6222	>	(rights = new MapReduceValuesToIntTask<K,V>
6223	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6224	>	rights, transformer, r, reducer)).fork();
6225	>	}
6226	>	for (Node<K,V> p; (p = advance()) != null; )
6227	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6228	>	result = r;
6229	>	CountedCompleter<?> c;
6230	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6231	>	@SuppressWarnings("unchecked")
6232	>	MapReduceValuesToIntTask<K,V>
6233	>	t = (MapReduceValuesToIntTask<K,V>)c,
6234	>	s = t.rights;
6235	>	while (s != null) {
6236	>	t.result = reducer.applyAsInt(t.result, s.result);
6237	>	s = t.rights = s.nextRight;
6238	>	}
6239	>	}
6240	>	}
6241	>	}
6242	>	}
6243	>
6244	>	@SuppressWarnings("serial")
6245	>	static final class MapReduceEntriesToIntTask<K,V>
6246	>	extends BulkTask<K,V,Integer> {
6247	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6248	>	final IntBinaryOperator reducer;
6249	>	final int basis;
6250	>	int result;
6251	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6252	>	MapReduceEntriesToIntTask
6253	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6254	>	MapReduceEntriesToIntTask<K,V> nextRight,
6255	>	ToIntFunction<Map.Entry<K,V>> transformer,
6256	>	int basis,
6257	>	IntBinaryOperator reducer) {
6258	>	super(p, b, i, f, t); this.nextRight = nextRight;
6259	>	this.transformer = transformer;
6260	>	this.basis = basis; this.reducer = reducer;
6261	>	}
6262	>	public final Integer getRawResult() { return result; }
6263	>	public final void compute() {
6264	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6265	>	final IntBinaryOperator reducer;
6266	>	if ((transformer = this.transformer) != null &&
6267	>	(reducer = this.reducer) != null) {
6268	>	int r = this.basis;
6269	>	for (int i = baseIndex, f, h; batch > 0 &&
6270	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6271	>	addToPendingCount(1);
6272	>	(rights = new MapReduceEntriesToIntTask<K,V>
6273	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6274	>	rights, transformer, r, reducer)).fork();
6275	>	}
6276	>	for (Node<K,V> p; (p = advance()) != null; )
6277	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6278	>	result = r;
6279	>	CountedCompleter<?> c;
6280	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6281	>	@SuppressWarnings("unchecked")
6282	>	MapReduceEntriesToIntTask<K,V>
6283	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6284	>	s = t.rights;
6285	>	while (s != null) {
6286	>	t.result = reducer.applyAsInt(t.result, s.result);
6287	>	s = t.rights = s.nextRight;
6288	>	}
6289	>	}
6290	>	}
6291	>	}
6292	>	}
6293	>
6294	>	@SuppressWarnings("serial")
6295	>	static final class MapReduceMappingsToIntTask<K,V>
6296	>	extends BulkTask<K,V,Integer> {
6297	>	final ToIntBiFunction<? super K, ? super V> transformer;
6298	>	final IntBinaryOperator reducer;
6299	>	final int basis;
6300	>	int result;
6301	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6302	>	MapReduceMappingsToIntTask
6303	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6304	>	MapReduceMappingsToIntTask<K,V> nextRight,
6305	>	ToIntBiFunction<? super K, ? super V> transformer,
6306	>	int basis,
6307	>	IntBinaryOperator reducer) {
6308	>	super(p, b, i, f, t); this.nextRight = nextRight;
6309	>	this.transformer = transformer;
6310	>	this.basis = basis; this.reducer = reducer;
6311	>	}
6312	>	public final Integer getRawResult() { return result; }
6313	>	public final void compute() {
6314	>	final ToIntBiFunction<? super K, ? super V> transformer;
6315	>	final IntBinaryOperator reducer;
6316	>	if ((transformer = this.transformer) != null &&
6317	>	(reducer = this.reducer) != null) {
6318	>	int r = this.basis;
6319	>	for (int i = baseIndex, f, h; batch > 0 &&
6320	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6321	>	addToPendingCount(1);
6322	>	(rights = new MapReduceMappingsToIntTask<K,V>
6323	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6324	>	rights, transformer, r, reducer)).fork();
6325	>	}
6326	>	for (Node<K,V> p; (p = advance()) != null; )
6327	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6328	>	result = r;
6329	>	CountedCompleter<?> c;
6330	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6331	>	@SuppressWarnings("unchecked")
6332	>	MapReduceMappingsToIntTask<K,V>
6333	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6334	>	s = t.rights;
6335	>	while (s != null) {
6336	>	t.result = reducer.applyAsInt(t.result, s.result);
6337	>	s = t.rights = s.nextRight;
6338	>	}
6339	>	}
6340	>	}
6341		}
6342		}
6343
6344		// Unsafe mechanics
6345	<	private static final sun.misc.Unsafe UNSAFE;
6346	<	private static final long SBASE;
6347	<	private static final int SSHIFT;
6348	<	private static final long TBASE;
6349	<	private static final int TSHIFT;
6345	>	private static final Unsafe U = Unsafe.getUnsafe();
6346	>	private static final long SIZECTL;
6347	>	private static final long TRANSFERINDEX;
6348	>	private static final long BASECOUNT;
6349	>	private static final long CELLSBUSY;
6350	>	private static final long CELLVALUE;
6351	>	private static final int ABASE;
6352	>	private static final int ASHIFT;
6353
6354		static {
1442	–	int ss, ts;
6355		try {
6356	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
6357	<	Class tc = HashEntry[].class;
6358	<	Class sc = Segment[].class;
6359	<	TBASE = UNSAFE.arrayBaseOffset(tc);
6360	<	SBASE = UNSAFE.arrayBaseOffset(sc);
6361	<	ts = UNSAFE.arrayIndexScale(tc);
6362	<	ss = UNSAFE.arrayIndexScale(sc);
6363	<	} catch (Exception e) {
6356	>	SIZECTL = U.objectFieldOffset
6357	>	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6358	>	TRANSFERINDEX = U.objectFieldOffset
6359	>	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6360	>	BASECOUNT = U.objectFieldOffset
6361	>	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6362	>	CELLSBUSY = U.objectFieldOffset
6363	>	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6364	>
6365	>	CELLVALUE = U.objectFieldOffset
6366	>	(CounterCell.class.getDeclaredField("value"));
6367	>
6368	>	ABASE = U.arrayBaseOffset(Node[].class);
6369	>	int scale = U.arrayIndexScale(Node[].class);
6370	>	if ((scale & (scale - 1)) != 0)
6371	>	throw new Error("array index scale not a power of two");
6372	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6373	>	} catch (ReflectiveOperationException e) {
6374		throw new Error(e);
6375		}
1454	–	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
1455	–	throw new Error("data type scale not a power of two");
1456	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1457	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
1458	–	}
6376
6377	+	// Reduce the risk of rare disastrous classloading in first call to
6378	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6379	+	Class<?> ensureLoaded = LockSupport.class;
6380	+	}
6381		}

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