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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.92 by dl, Sat Dec 2 20:55:01 2006 UTC vs.
Revision 1.248 by jsr166, Sun Sep 1 05:04:18 2013 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://creativecommons.org/licenses/publicdomain
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.Comparator;
17	>	import java.util.Enumeration;
18	>	import java.util.HashMap;
19	>	import java.util.Hashtable;
20	>	import java.util.Iterator;
21	>	import java.util.Map;
22	>	import java.util.NoSuchElementException;
23	>	import java.util.Set;
24	>	import java.util.Spliterator;
25	>	import java.util.concurrent.ConcurrentMap;
26	>	import java.util.concurrent.ForkJoinPool;
27	>	import java.util.concurrent.atomic.AtomicReference;
28	>	import java.util.concurrent.locks.LockSupport;
29	>	import java.util.concurrent.locks.ReentrantLock;
30	>	import java.util.function.BiConsumer;
31	>	import java.util.function.BiFunction;
32	>	import java.util.function.BinaryOperator;
33	>	import java.util.function.Consumer;
34	>	import java.util.function.DoubleBinaryOperator;
35	>	import java.util.function.Function;
36	>	import java.util.function.IntBinaryOperator;
37	>	import java.util.function.LongBinaryOperator;
38	>	import java.util.function.ToDoubleBiFunction;
39	>	import java.util.function.ToDoubleFunction;
40	>	import java.util.function.ToIntBiFunction;
41	>	import java.util.function.ToIntFunction;
42	>	import java.util.function.ToLongBiFunction;
43	>	import java.util.function.ToLongFunction;
44	>	import java.util.stream.Stream;
45
46		/**
47		* A hash table supporting full concurrency of retrievals and
48	<	* adjustable expected concurrency for updates. This class obeys the
48	>	* high expected concurrency for updates. This class obeys the
49		* same functional specification as {@link java.util.Hashtable}, and
50		* includes versions of methods corresponding to each method of
51	<	* <tt>Hashtable</tt>. However, even though all operations are
51	>	* {@code Hashtable}. However, even though all operations are
52		* thread-safe, retrieval operations do <em>not</em> entail locking,
53		* and there is <em>not</em> any support for locking the entire table
54		* in a way that prevents all access.  This class is fully
55	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
55	>	* interoperable with {@code Hashtable} in programs that rely on its
56		* thread safety but not on its synchronization details.
57		*
58	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
59	<	* block, so may overlap with update operations (including
60	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
61	<	* of the most recently <em>completed</em> update operations holding
62	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
63	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
64	<	* removal of only some entries.  Similarly, Iterators and
65	<	* Enumerations return elements reflecting the state of the hash table
66	<	* at some point at or since the creation of the iterator/enumeration.
67	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
58	>	* <p>Retrieval operations (including {@code get}) generally do not
59	>	* block, so may overlap with update operations (including {@code put}
60	>	* and {@code remove}). Retrievals reflect the results of the most
61	>	* recently <em>completed</em> update operations holding upon their
62	>	* onset. (More formally, an update operation for a given key bears a
63	>	* <em>happens-before</em> relation with any (non-null) retrieval for
64	>	* that key reporting the updated value.)  For aggregate operations
65	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
66	>	* reflect insertion or removal of only some entries.  Similarly,
67	>	* Iterators, Spliterators and Enumerations return elements reflecting the
68	>	* state of the hash table at some point at or since the creation of the
69	>	* iterator/enumeration.  They do <em>not</em> throw {@link
70	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
71		* However, iterators are designed to be used by only one thread at a time.
72	+	* Bear in mind that the results of aggregate status methods including
73	+	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
74	+	* useful only when a map is not undergoing concurrent updates in other threads.
75	+	* Otherwise the results of these methods reflect transient states
76	+	* that may be adequate for monitoring or estimation purposes, but not
77	+	* for program control.
78	+	*
79	+	* <p>The table is dynamically expanded when there are too many
80	+	* collisions (i.e., keys that have distinct hash codes but fall into
81	+	* the same slot modulo the table size), with the expected average
82	+	* effect of maintaining roughly two bins per mapping (corresponding
83	+	* to a 0.75 load factor threshold for resizing). There may be much
84	+	* variance around this average as mappings are added and removed, but
85	+	* overall, this maintains a commonly accepted time/space tradeoff for
86	+	* hash tables.  However, resizing this or any other kind of hash
87	+	* table may be a relatively slow operation. When possible, it is a
88	+	* good idea to provide a size estimate as an optional {@code
89	+	* initialCapacity} constructor argument. An additional optional
90	+	* {@code loadFactor} constructor argument provides a further means of
91	+	* customizing initial table capacity by specifying the table density
92	+	* to be used in calculating the amount of space to allocate for the
93	+	* given number of elements.  Also, for compatibility with previous
94	+	* versions of this class, constructors may optionally specify an
95	+	* expected {@code concurrencyLevel} as an additional hint for
96	+	* internal sizing.  Note that using many keys with exactly the same
97	+	* {@code hashCode()} is a sure way to slow down performance of any
98	+	* hash table. To ameliorate impact, when keys are {@link Comparable},
99	+	* this class may use comparison order among keys to help break ties.
100	+	*
101	+	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
102	+	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
103	+	* (using {@link #keySet(Object)} when only keys are of interest, and the
104	+	* mapped values are (perhaps transiently) not used or all take the
105	+	* same mapping value.
106		*
107	<	* <p> The allowed concurrency among update operations is guided by
108	<	* the optional <tt>concurrencyLevel</tt> constructor argument
109	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
110	<	* table is internally partitioned to try to permit the indicated
111	<	* number of concurrent updates without contention. Because placement
112	<	* 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.
107	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
108	>	* form of histogram or multiset) by using {@link
109	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
110	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
111	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
112	>	* {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();}
113		*
114		* <p>This class and its views and iterators implement all of the
115		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
116		* interfaces.
117		*
118	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
119	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
118	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
119	>	* does <em>not</em> allow {@code null} to be used as a key or value.
120	>	*
121	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
122	>	* operations that, unlike most {@link Stream} methods, are designed
123	>	* to be safely, and often sensibly, applied even with maps that are
124	>	* being concurrently updated by other threads; for example, when
125	>	* computing a snapshot summary of the values in a shared registry.
126	>	* There are three kinds of operation, each with four forms, accepting
127	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
128	>	* and/or return values. Because the elements of a ConcurrentHashMap
129	>	* are not ordered in any particular way, and may be processed in
130	>	* different orders in different parallel executions, the correctness
131	>	* of supplied functions should not depend on any ordering, or on any
132	>	* other objects or values that may transiently change while
133	>	* computation is in progress; and except for forEach actions, should
134	>	* ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry}
135	>	* objects do not support method {@code setValue}.
136	>	*
137	>	* <ul>
138	>	* <li> forEach: Perform a given action on each element.
139	>	* A variant form applies a given transformation on each element
140	>	* before performing the action.</li>
141	>	*
142	>	* <li> search: Return the first available non-null result of
143	>	* applying a given function on each element; skipping further
144	>	* search when a result is found.</li>
145	>	*
146	>	* <li> reduce: Accumulate each element.  The supplied reduction
147	>	* function cannot rely on ordering (more formally, it should be
148	>	* both associative and commutative).  There are five variants:
149	>	*
150	>	* <ul>
151	>	*
152	>	* <li> Plain reductions. (There is not a form of this method for
153	>	* (key, value) function arguments since there is no corresponding
154	>	* return type.)</li>
155	>	*
156	>	* <li> Mapped reductions that accumulate the results of a given
157	>	* function applied to each element.</li>
158	>	*
159	>	* <li> Reductions to scalar doubles, longs, and ints, using a
160	>	* given basis value.</li>
161	>	*
162	>	* </ul>
163	>	* </li>
164	>	* </ul>
165	>	*
166	>	* <p>These bulk operations accept a {@code parallelismThreshold}
167	>	* argument. Methods proceed sequentially if the current map size is
168	>	* estimated to be less than the given threshold. Using a value of
169	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
170	>	* of {@code 1} results in maximal parallelism by partitioning into
171	>	* enough subtasks to fully utilize the {@link
172	>	* ForkJoinPool#commonPool()} that is used for all parallel
173	>	* computations. Normally, you would initially choose one of these
174	>	* extreme values, and then measure performance of using in-between
175	>	* values that trade off overhead versus throughput.
176	>	*
177	>	* <p>The concurrency properties of bulk operations follow
178	>	* from those of ConcurrentHashMap: Any non-null result returned
179	>	* from {@code get(key)} and related access methods bears a
180	>	* happens-before relation with the associated insertion or
181	>	* update.  The result of any bulk operation reflects the
182	>	* composition of these per-element relations (but is not
183	>	* necessarily atomic with respect to the map as a whole unless it
184	>	* is somehow known to be quiescent).  Conversely, because keys
185	>	* and values in the map are never null, null serves as a reliable
186	>	* atomic indicator of the current lack of any result.  To
187	>	* maintain this property, null serves as an implicit basis for
188	>	* all non-scalar reduction operations. For the double, long, and
189	>	* int versions, the basis should be one that, when combined with
190	>	* any other value, returns that other value (more formally, it
191	>	* should be the identity element for the reduction). Most common
192	>	* reductions have these properties; for example, computing a sum
193	>	* with basis 0 or a minimum with basis MAX_VALUE.
194	>	*
195	>	* <p>Search and transformation functions provided as arguments
196	>	* should similarly return null to indicate the lack of any result
197	>	* (in which case it is not used). In the case of mapped
198	>	* reductions, this also enables transformations to serve as
199	>	* filters, returning null (or, in the case of primitive
200	>	* specializations, the identity basis) if the element should not
201	>	* be combined. You can create compound transformations and
202	>	* filterings by composing them yourself under this "null means
203	>	* there is nothing there now" rule before using them in search or
204	>	* reduce operations.
205	>	*
206	>	* <p>Methods accepting and/or returning Entry arguments maintain
207	>	* key-value associations. They may be useful for example when
208	>	* finding the key for the greatest value. Note that "plain" Entry
209	>	* arguments can be supplied using {@code new
210	>	* AbstractMap.SimpleEntry(k,v)}.
211	>	*
212	>	* <p>Bulk operations may complete abruptly, throwing an
213	>	* exception encountered in the application of a supplied
214	>	* function. Bear in mind when handling such exceptions that other
215	>	* concurrently executing functions could also have thrown
216	>	* exceptions, or would have done so if the first exception had
217	>	* not occurred.
218	>	*
219	>	* <p>Speedups for parallel compared to sequential forms are common
220	>	* but not guaranteed.  Parallel operations involving brief functions
221	>	* on small maps may execute more slowly than sequential forms if the
222	>	* underlying work to parallelize the computation is more expensive
223	>	* than the computation itself.  Similarly, parallelization may not
224	>	* lead to much actual parallelism if all processors are busy
225	>	* performing unrelated tasks.
226	>	*
227	>	* <p>All arguments to all task methods must be non-null.
228		*
229		* <p>This class is a member of the
230		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 70 | Line 235 | import java.io.ObjectOutputStream;
235		* @param <K> the type of keys maintained by this map
236		* @param <V> the type of mapped values
237		*/
238	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
239	<	implements ConcurrentMap<K, V>, Serializable {
238	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
239	>	implements ConcurrentMap<K,V>, Serializable {
240		private static final long serialVersionUID = 7249069246763182397L;
241
242		/*
243	<	* The basic strategy is to subdivide the table among Segments,
244	<	* each of which itself is a concurrently readable hash table.
243	>	* Overview:
244	>	*
245	>	* The primary design goal of this hash table is to maintain
246	>	* concurrent readability (typically method get(), but also
247	>	* iterators and related methods) while minimizing update
248	>	* contention. Secondary goals are to keep space consumption about
249	>	* the same or better than java.util.HashMap, and to support high
250	>	* initial insertion rates on an empty table by many threads.
251	>	*
252	>	* This map usually acts as a binned (bucketed) hash table.  Each
253	>	* key-value mapping is held in a Node.  Most nodes are instances
254	>	* of the basic Node class with hash, key, value, and next
255	>	* fields. However, various subclasses exist: TreeNodes are
256	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
257	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
258	>	* of bins during resizing. ReservationNodes are used as
259	>	* placeholders while establishing values in computeIfAbsent and
260	>	* related methods.  The types TreeBin, ForwardingNode, and
261	>	* ReservationNode do not hold normal user keys, values, or
262	>	* hashes, and are readily distinguishable during search etc
263	>	* because they have negative hash fields and null key and value
264	>	* fields. (These special nodes are either uncommon or transient,
265	>	* so the impact of carrying around some unused fields is
266	>	* insignificant.)
267	>	*
268	>	* The table is lazily initialized to a power-of-two size upon the
269	>	* first insertion.  Each bin in the table normally contains a
270	>	* list of Nodes (most often, the list has only zero or one Node).
271	>	* Table accesses require volatile/atomic reads, writes, and
272	>	* CASes.  Because there is no other way to arrange this without
273	>	* adding further indirections, we use intrinsics
274	>	* (sun.misc.Unsafe) operations.
275	>	*
276	>	* We use the top (sign) bit of Node hash fields for control
277	>	* purposes -- it is available anyway because of addressing
278	>	* constraints.  Nodes with negative hash fields are specially
279	>	* handled or ignored in map methods.
280	>	*
281	>	* Insertion (via put or its variants) of the first node in an
282	>	* empty bin is performed by just CASing it to the bin.  This is
283	>	* by far the most common case for put operations under most
284	>	* key/hash distributions.  Other update operations (insert,
285	>	* delete, and replace) require locks.  We do not want to waste
286	>	* the space required to associate a distinct lock object with
287	>	* each bin, so instead use the first node of a bin list itself as
288	>	* a lock. Locking support for these locks relies on builtin
289	>	* "synchronized" monitors.
290	>	*
291	>	* Using the first node of a list as a lock does not by itself
292	>	* suffice though: When a node is locked, any update must first
293	>	* validate that it is still the first node after locking it, and
294	>	* retry if not. Because new nodes are always appended to lists,
295	>	* once a node is first in a bin, it remains first until deleted
296	>	* or the bin becomes invalidated (upon resizing).
297	>	*
298	>	* The main disadvantage of per-bin locks is that other update
299	>	* operations on other nodes in a bin list protected by the same
300	>	* lock can stall, for example when user equals() or mapping
301	>	* functions take a long time.  However, statistically, under
302	>	* random hash codes, this is not a common problem.  Ideally, the
303	>	* frequency of nodes in bins follows a Poisson distribution
304	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
305	>	* parameter of about 0.5 on average, given the resizing threshold
306	>	* of 0.75, although with a large variance because of resizing
307	>	* granularity. Ignoring variance, the expected occurrences of
308	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
309	>	* first values are:
310	>	*
311	>	* 0:    0.60653066
312	>	* 1:    0.30326533
313	>	* 2:    0.07581633
314	>	* 3:    0.01263606
315	>	* 4:    0.00157952
316	>	* 5:    0.00015795
317	>	* 6:    0.00001316
318	>	* 7:    0.00000094
319	>	* 8:    0.00000006
320	>	* more: less than 1 in ten million
321	>	*
322	>	* Lock contention probability for two threads accessing distinct
323	>	* elements is roughly 1 / (8 * #elements) under random hashes.
324	>	*
325	>	* Actual hash code distributions encountered in practice
326	>	* sometimes deviate significantly from uniform randomness.  This
327	>	* includes the case when N > (1<<30), so some keys MUST collide.
328	>	* Similarly for dumb or hostile usages in which multiple keys are
329	>	* designed to have identical hash codes or ones that differs only
330	>	* in masked-out high bits. So we use a secondary strategy that
331	>	* applies when the number of nodes in a bin exceeds a
332	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
333	>	* specialized form of red-black trees), bounding search time to
334	>	* O(log N).  Each search step in a TreeBin is at least twice as
335	>	* slow as in a regular list, but given that N cannot exceed
336	>	* (1<<64) (before running out of addresses) this bounds search
337	>	* steps, lock hold times, etc, to reasonable constants (roughly
338	>	* 100 nodes inspected per operation worst case) so long as keys
339	>	* are Comparable (which is very common -- String, Long, etc).
340	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
341	>	* traversal pointers as regular nodes, so can be traversed in
342	>	* iterators in the same way.
343	>	*
344	>	* The table is resized when occupancy exceeds a percentage
345	>	* threshold (nominally, 0.75, but see below).  Any thread
346	>	* noticing an overfull bin may assist in resizing after the
347	>	* initiating thread allocates and sets up the replacement array.
348	>	* However, rather than stalling, these other threads may proceed
349	>	* with insertions etc.  The use of TreeBins shields us from the
350	>	* worst case effects of overfilling while resizes are in
351	>	* progress.  Resizing proceeds by transferring bins, one by one,
352	>	* from the table to the next table. However, threads claim small
353	>	* blocks of indices to transfer (via field transferIndex) before
354	>	* doing so, reducing contention.  Because we are using
355	>	* power-of-two expansion, the elements from each bin must either
356	>	* stay at same index, or move with a power of two offset. We
357	>	* eliminate unnecessary node creation by catching cases where old
358	>	* nodes can be reused because their next fields won't change.  On
359	>	* average, only about one-sixth of them need cloning when a table
360	>	* doubles. The nodes they replace will be garbage collectable as
361	>	* soon as they are no longer referenced by any reader thread that
362	>	* may be in the midst of concurrently traversing table.  Upon
363	>	* transfer, the old table bin contains only a special forwarding
364	>	* node (with hash field "MOVED") that contains the next table as
365	>	* its key. On encountering a forwarding node, access and update
366	>	* operations restart, using 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 refering 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
105	<	* be a power of two <= 1<<30 to ensure that entries are indexable
106	<	* 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 maximum number of segments to allow; used to bound
502	<	* constructor arguments.
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 MAX_SEGMENTS = 1 << 16; // slightly conservative
507	>	private static final float LOAD_FACTOR = 0.75f;
508
509		/**
510	<	* Number of unsynchronized retries in size and containsValue
511	<	* methods before resorting to locking. This is used to avoid
512	<	* unbounded retries if tables undergo continuous modification
513	<	* which would make it impossible to obtain an accurate result.
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 RETRIES_BEFORE_LOCK = 2;
517	>	static final int TREEIFY_THRESHOLD = 8;
518
519	<	/* ---------------- Fields -------------- */
519	>	/**
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 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	>	* Encodings for Node hash fields. See above for explanation.
545	>	*/
546	>	static final int MOVED     = -1; // hash for forwarding nodes
547	>	static final int TREEBIN   = -2; // hash for roots of trees
548	>	static final int RESERVED  = -3; // hash for transient reservations
549	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
550	>
551	>	/** Number of CPUS, to place bounds on some sizings */
552	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
553	>
554	>	/** For serialization compatibility. */
555	>	private static final ObjectStreamField[] serialPersistentFields = {
556	>	new ObjectStreamField("segments", Segment[].class),
557	>	new ObjectStreamField("segmentMask", Integer.TYPE),
558	>	new ObjectStreamField("segmentShift", Integer.TYPE)
559	>	};
560	>
561	>	/* ---------------- Nodes -------------- */
562
563		/**
564	<	* The segments, each of which is a specialized hash table
564	>	* Key-value entry.  This class is never exported out as a
565	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
566	>	* MapEntry below), but can be used for read-only traversals used
567	>	* in bulk tasks.  Subclasses of Node with a negative hash field
568	>	* are special, and contain null keys and values (but are never
569	>	* exported).  Otherwise, keys and vals are never null.
570		*/
571	<	final Segment<K,V>[] segments;
571	>	static class Node<K,V> implements Map.Entry<K,V> {
572	>	final int hash;
573	>	final K key;
574	>	volatile V val;
575	>	volatile Node<K,V> next;
576	>
577	>	Node(int hash, K key, V val, Node<K,V> next) {
578	>	this.hash = hash;
579	>	this.key = key;
580	>	this.val = val;
581	>	this.next = next;
582	>	}
583
584	<	transient Set<K> keySet;
585	<	transient Set<Map.Entry<K,V>> entrySet;
586	<	transient Collection<V> values;
584	>	public final K getKey()       { return key; }
585	>	public final V getValue()     { return val; }
586	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
587	>	public final String toString(){ return key + "=" + val; }
588	>	public final V setValue(V value) {
589	>	throw new UnsupportedOperationException();
590	>	}
591
592	<	/* ---------------- Small Utilities -------------- */
592	>	public final boolean equals(Object o) {
593	>	Object k, v, u; Map.Entry<?,?> e;
594	>	return ((o instanceof Map.Entry) &&
595	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
596	>	(v = e.getValue()) != null &&
597	>	(k == key || k.equals(key)) &&
598	>	(v == (u = val) || v.equals(u)));
599	>	}
600	>
601	>	/**
602	>	* Virtualized support for map.get(); overridden in subclasses.
603	>	*/
604	>	Node<K,V> find(int h, Object k) {
605	>	Node<K,V> e = this;
606	>	if (k != null) {
607	>	do {
608	>	K ek;
609	>	if (e.hash == h &&
610	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
611	>	return e;
612	>	} while ((e = e.next) != null);
613	>	}
614	>	return null;
615	>	}
616	>	}
617	>
618	>	/* ---------------- Static utilities -------------- */
619
620		/**
621	<	* Applies a supplemental hash function to a given hashCode, which
622	<	* defends against poor quality hash functions.  This is critical
623	<	* because ConcurrentHashMap uses power-of-two length hash tables,
624	<	* that otherwise encounter collisions for hashCodes that do not
625	<	* differ in lower bits.
621	>	* Spreads (XORs) higher bits of hash to lower and also forces top
622	>	* bit to 0. Because the table uses power-of-two masking, sets of
623	>	* hashes that vary only in bits above the current mask will
624	>	* always collide. (Among known examples are sets of Float keys
625	>	* holding consecutive whole numbers in small tables.)  So we
626	>	* apply a transform that spreads the impact of higher bits
627	>	* downward. There is a tradeoff between speed, utility, and
628	>	* quality of bit-spreading. Because many common sets of hashes
629	>	* are already reasonably distributed (so don't benefit from
630	>	* spreading), and because we use trees to handle large sets of
631	>	* collisions in bins, we just XOR some shifted bits in the
632	>	* cheapest possible way to reduce systematic lossage, as well as
633	>	* to incorporate impact of the highest bits that would otherwise
634	>	* never be used in index calculations because of table bounds.
635		*/
636	<	private static int hash(int h) {
637	<	// Spread bits to regularize both segment and index locations,
157	<	// using variant of Jenkins's shift-based hash.
158	<	h += ~(h << 13);
159	<	h ^= h >>> 7;
160	<	h += h << 3;
161	<	h ^= h >>> 17;
162	<	h += h << 5;
163	<	return h;
636	>	static final int spread(int h) {
637	>	return (h ^ (h >>> 16)) & HASH_BITS;
638		}
639
640		/**
641	<	* Returns the segment that should be used for key with given hash
642	<	* @param hash the hash code for the key
169	<	* @return the segment
641	>	* Returns a power of two table size for the given desired capacity.
642	>	* See Hackers Delight, sec 3.2
643		*/
644	<	final Segment<K,V> segmentFor(int hash) {
645	<	return segments[(hash >>> segmentShift) & segmentMask];
644	>	private static final int tableSizeFor(int c) {
645	>	int n = c - 1;
646	>	n |= n >>> 1;
647	>	n |= n >>> 2;
648	>	n |= n >>> 4;
649	>	n |= n >>> 8;
650	>	n |= n >>> 16;
651	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
652		}
653
654	<	/* ---------------- Inner Classes -------------- */
654	>	/**
655	>	* Returns x's Class if it is of the form "class C implements
656	>	* Comparable<C>", else null.
657	>	*/
658	>	static Class<?> comparableClassFor(Object x) {
659	>	if (x instanceof Comparable) {
660	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
661	>	if ((c = x.getClass()) == String.class) // bypass checks
662	>	return c;
663	>	if ((ts = c.getGenericInterfaces()) != null) {
664	>	for (int i = 0; i < ts.length; ++i) {
665	>	if (((t = ts[i]) instanceof ParameterizedType) &&
666	>	((p = (ParameterizedType)t).getRawType() ==
667	>	Comparable.class) &&
668	>	(as = p.getActualTypeArguments()) != null &&
669	>	as.length == 1 && as[0] == c) // type arg is c
670	>	return c;
671	>	}
672	>	}
673	>	}
674	>	return null;
675	>	}
676
677		/**
678	<	* ConcurrentHashMap list entry. Note that this is never exported
679	<	* out as a user-visible Map.Entry.
180	<	*
181	<	* Because the value field is volatile, not final, it is legal wrt
182	<	* the Java Memory Model for an unsynchronized reader to see null
183	<	* instead of initial value when read via a data race.  Although a
184	<	* reordering leading to this is not likely to ever actually
185	<	* occur, the Segment.readValueUnderLock method is used as a
186	<	* backup in case a null (pre-initialized) value is ever seen in
187	<	* an unsynchronized access method.
678	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
679	>	* class), else 0.
680		*/
681	<	static final class HashEntry<K,V> {
682	<	final K key;
683	<	final int hash;
684	<	volatile V value;
685	<	final HashEntry<K,V> next;
681	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
682	>	static int compareComparables(Class<?> kc, Object k, Object x) {
683	>	return (x == null || x.getClass() != kc ? 0 :
684	>	((Comparable)k).compareTo(x));
685	>	}
686
687	<	HashEntry(K key, int hash, HashEntry<K,V> next, V value) {
196	<	this.key = key;
197	<	this.hash = hash;
198	<	this.next = next;
199	<	this.value = value;
200	<	}
687	>	/* ---------------- Table element access -------------- */
688
689	<	@SuppressWarnings("unchecked")
690	<	static final <K,V> HashEntry<K,V>[] newArray(int i) {
691	<	return new HashEntry[i];
692	<	}
689	>	/*
690	>	* Volatile access methods are used for table elements as well as
691	>	* elements of in-progress next table while resizing.  All uses of
692	>	* the tab arguments must be null checked by callers.  All callers
693	>	* also paranoically precheck that tab's length is not zero (or an
694	>	* equivalent check), thus ensuring that any index argument taking
695	>	* the form of a hash value anded with (length - 1) is a valid
696	>	* index.  Note that, to be correct wrt arbitrary concurrency
697	>	* errors by users, these checks must operate on local variables,
698	>	* which accounts for some odd-looking inline assignments below.
699	>	* Note that calls to setTabAt always occur within locked regions,
700	>	* and so in principle require only release ordering, not need
701	>	* full volatile semantics, but are currently coded as volatile
702	>	* writes to be conservative.
703	>	*/
704	>
705	>	@SuppressWarnings("unchecked")
706	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
707	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
708		}
709
710	+	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
711	+	Node<K,V> c, Node<K,V> v) {
712	+	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
713	+	}
714	+
715	+	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
716	+	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
717	+	}
718	+
719	+	/* ---------------- Fields -------------- */
720	+
721		/**
722	<	* Segments are specialized versions of hash tables.  This
723	<	* subclasses from ReentrantLock opportunistically, just to
211	<	* simplify some locking and avoid separate construction.
722	>	* The array of bins. Lazily initialized upon first insertion.
723	>	* Size is always a power of two. Accessed directly by iterators.
724		*/
725	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
214	<	/*
215	<	* Segments maintain a table of entry lists that are ALWAYS
216	<	* kept in a consistent state, so can be read without locking.
217	<	* Next fields of nodes are immutable (final).  All list
218	<	* additions are performed at the front of each bin. This
219	<	* makes it easy to check changes, and also fast to traverse.
220	<	* When nodes would otherwise be changed, new nodes are
221	<	* created to replace them. This works well for hash tables
222	<	* since the bin lists tend to be short. (The average length
223	<	* is less than two for the default load factor threshold.)
224	<	*
225	<	* Read operations can thus proceed without locking, but rely
226	<	* on selected uses of volatiles to ensure that completed
227	<	* write operations performed by other threads are
228	<	* noticed. For most purposes, the "count" field, tracking the
229	<	* number of elements, serves as that volatile variable
230	<	* ensuring visibility.  This is convenient because this field
231	<	* needs to be read in many read operations anyway:
232	<	*
233	<	*   - All (unsynchronized) read operations must first read the
234	<	*     "count" field, and should not look at table entries if
235	<	*     it is 0.
236	<	*
237	<	*   - All (synchronized) write operations should write to
238	<	*     the "count" field after structurally changing any bin.
239	<	*     The operations must not take any action that could even
240	<	*     momentarily cause a concurrent read operation to see
241	<	*     inconsistent data. This is made easier by the nature of
242	<	*     the read operations in Map. For example, no operation
243	<	*     can reveal that the table has grown but the threshold
244	<	*     has not yet been updated, so there are no atomicity
245	<	*     requirements for this with respect to reads.
246	<	*
247	<	* As a guide, all critical volatile reads and writes to the
248	<	* count field are marked in code comments.
249	<	*/
725	>	transient volatile Node<K,V>[] table;
726
727	<	private static final long serialVersionUID = 2249069246763182397L;
727	>	/**
728	>	* The next table to use; non-null only while resizing.
729	>	*/
730	>	private transient volatile Node<K,V>[] nextTable;
731
732	<	/**
733	<	* The number of elements in this segment's region.
734	<	*/
735	<	transient volatile int count;
732	>	/**
733	>	* Base counter value, used mainly when there is no contention,
734	>	* but also as a fallback during table initialization
735	>	* races. Updated via CAS.
736	>	*/
737	>	private transient volatile long baseCount;
738
739	<	/**
740	<	* Number of updates that alter the size of the table. This is
741	<	* used during bulk-read methods to make sure they see a
742	<	* consistent snapshot: If modCounts change during a traversal
743	<	* of segments computing size or checking containsValue, then
744	<	* we might have an inconsistent view of state so (usually)
745	<	* must retry.
746	<	*/
747	<	transient int modCount;
739	>	/**
740	>	* Table initialization and resizing control.  When negative, the
741	>	* table is being initialized or resized: -1 for initialization,
742	>	* else -(1 + the number of active resizing threads).  Otherwise,
743	>	* when table is null, holds the initial table size to use upon
744	>	* creation, or 0 for default. After initialization, holds the
745	>	* next element count value upon which to resize the table.
746	>	*/
747	>	private transient volatile int sizeCtl;
748
749	<	/**
750	<	* The table is rehashed when its size exceeds this threshold.
751	<	* (The value of this field is always <tt>(int)(capacity *
752	<	* loadFactor)</tt>.)
272	<	*/
273	<	transient int threshold;
749	>	/**
750	>	* The next table index (plus one) to split while resizing.
751	>	*/
752	>	private transient volatile int transferIndex;
753
754	<	/**
755	<	* The per-segment table.
756	<	*/
757	<	transient volatile HashEntry<K,V>[] table;
754	>	/**
755	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
756	>	*/
757	>	private transient volatile int cellsBusy;
758
759	<	/**
760	<	* The load factor for the hash table.  Even though this value
761	<	* is same for all segments, it is replicated to avoid needing
762	<	* links to outer object.
284	<	* @serial
285	<	*/
286	<	final float loadFactor;
759	>	/**
760	>	* Table of counter cells. When non-null, size is a power of 2.
761	>	*/
762	>	private transient volatile CounterCell[] counterCells;
763
764	<	Segment(int initialCapacity, float lf) {
765	<	loadFactor = lf;
766	<	setTable(HashEntry.<K,V>newArray(initialCapacity));
767	<	}
764	>	// views
765	>	private transient KeySetView<K,V> keySet;
766	>	private transient ValuesView<K,V> values;
767	>	private transient EntrySetView<K,V> entrySet;
768
293	–	@SuppressWarnings("unchecked")
294	–	static final <K,V> Segment<K,V>[] newArray(int i) {
295	–	return new Segment[i];
296	–	}
769
770	<	/**
299	<	* Sets table to new HashEntry array.
300	<	* Call only while holding lock or in constructor.
301	<	*/
302	<	void setTable(HashEntry<K,V>[] newTable) {
303	<	threshold = (int)(newTable.length * loadFactor);
304	<	table = newTable;
305	<	}
770	>	/* ---------------- Public operations -------------- */
771
772	<	/**
773	<	* Returns properly casted first entry of bin for given hash.
774	<	*/
775	<	HashEntry<K,V> getFirst(int hash) {
776	<	HashEntry<K,V>[] tab = table;
312	<	return tab[hash & (tab.length - 1)];
313	<	}
772	>	/**
773	>	* Creates a new, empty map with the default initial table size (16).
774	>	*/
775	>	public ConcurrentHashMap() {
776	>	}
777
778	<	/**
779	<	* Reads value field of an entry under lock. Called if value
780	<	* field ever appears to be null. This is possible only if a
781	<	* compiler happens to reorder a HashEntry initialization with
782	<	* its table assignment, which is legal under memory model
783	<	* but is not known to ever occur.
784	<	*/
785	<	V readValueUnderLock(HashEntry<K,V> e) {
786	<	lock();
787	<	try {
788	<	return e.value;
789	<	} finally {
790	<	unlock();
791	<	}
792	<	}
778	>	/**
779	>	* Creates a new, empty map with an initial table size
780	>	* accommodating the specified number of elements without the need
781	>	* to dynamically resize.
782	>	*
783	>	* @param initialCapacity The implementation performs internal
784	>	* sizing to accommodate this many elements.
785	>	* @throws IllegalArgumentException if the initial capacity of
786	>	* elements is negative
787	>	*/
788	>	public ConcurrentHashMap(int initialCapacity) {
789	>	if (initialCapacity < 0)
790	>	throw new IllegalArgumentException();
791	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
792	>	MAXIMUM_CAPACITY :
793	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
794	>	this.sizeCtl = cap;
795	>	}
796
797	<	/* Specialized implementations of map methods */
797	>	/**
798	>	* Creates a new map with the same mappings as the given map.
799	>	*
800	>	* @param m the map
801	>	*/
802	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
803	>	this.sizeCtl = DEFAULT_CAPACITY;
804	>	putAll(m);
805	>	}
806
807	<	V get(Object key, int hash) {
808	<	if (count != 0) { // read-volatile
809	<	HashEntry<K,V> e = getFirst(hash);
810	<	while (e != null) {
811	<	if (e.hash == hash && key.equals(e.key)) {
812	<	V v = e.value;
813	<	if (v != null)
814	<	return v;
815	<	return readValueUnderLock(e); // recheck
816	<	}
817	<	e = e.next;
818	<	}
819	<	}
820	<	return null;
821	<	}
807	>	/**
808	>	* Creates a new, empty map with an initial table size based on
809	>	* the given number of elements ({@code initialCapacity}) and
810	>	* initial table density ({@code loadFactor}).
811	>	*
812	>	* @param initialCapacity the initial capacity. The implementation
813	>	* performs internal sizing to accommodate this many elements,
814	>	* given the specified load factor.
815	>	* @param loadFactor the load factor (table density) for
816	>	* establishing the initial table size
817	>	* @throws IllegalArgumentException if the initial capacity of
818	>	* elements is negative or the load factor is nonpositive
819	>	*
820	>	* @since 1.6
821	>	*/
822	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
823	>	this(initialCapacity, loadFactor, 1);
824	>	}
825
826	<	boolean containsKey(Object key, int hash) {
827	<	if (count != 0) { // read-volatile
828	<	HashEntry<K,V> e = getFirst(hash);
829	<	while (e != null) {
830	<	if (e.hash == hash && key.equals(e.key))
831	<	return true;
832	<	e = e.next;
833	<	}
834	<	}
835	<	return false;
836	<	}
826	>	/**
827	>	* Creates a new, empty map with an initial table size based on
828	>	* the given number of elements ({@code initialCapacity}), table
829	>	* density ({@code loadFactor}), and number of concurrently
830	>	* updating threads ({@code concurrencyLevel}).
831	>	*
832	>	* @param initialCapacity the initial capacity. The implementation
833	>	* performs internal sizing to accommodate this many elements,
834	>	* given the specified load factor.
835	>	* @param loadFactor the load factor (table density) for
836	>	* establishing the initial table size
837	>	* @param concurrencyLevel the estimated number of concurrently
838	>	* updating threads. The implementation may use this value as
839	>	* a sizing hint.
840	>	* @throws IllegalArgumentException if the initial capacity is
841	>	* negative or the load factor or concurrencyLevel are
842	>	* nonpositive
843	>	*/
844	>	public ConcurrentHashMap(int initialCapacity,
845	>	float loadFactor, int concurrencyLevel) {
846	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
847	>	throw new IllegalArgumentException();
848	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
849	>	initialCapacity = concurrencyLevel;   // as estimated threads
850	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
851	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
852	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
853	>	this.sizeCtl = cap;
854	>	}
855
856	<	boolean containsValue(Object value) {
362	<	if (count != 0) { // read-volatile
363	<	HashEntry<K,V>[] tab = table;
364	<	int len = tab.length;
365	<	for (int i = 0 ; i < len; i++) {
366	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
367	<	V v = e.value;
368	<	if (v == null) // recheck
369	<	v = readValueUnderLock(e);
370	<	if (value.equals(v))
371	<	return true;
372	<	}
373	<	}
374	<	}
375	<	return false;
376	<	}
856	>	// Original (since JDK1.2) Map methods
857
858	<	boolean replace(K key, int hash, V oldValue, V newValue) {
859	<	lock();
860	<	try {
861	<	HashEntry<K,V> e = getFirst(hash);
862	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
863	<	e = e.next;
864	<
865	<	boolean replaced = false;
866	<	if (e != null && oldValue.equals(e.value)) {
867	<	replaced = true;
868	<	e.value = newValue;
869	<	}
870	<	return replaced;
871	<	} finally {
872	<	unlock();
858	>	/**
859	>	* {@inheritDoc}
860	>	*/
861	>	public int size() {
862	>	long n = sumCount();
863	>	return ((n < 0L) ? 0 :
864	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
865	>	(int)n);
866	>	}
867	>
868	>	/**
869	>	* {@inheritDoc}
870	>	*/
871	>	public boolean isEmpty() {
872	>	return sumCount() <= 0L; // ignore transient negative values
873	>	}
874	>
875	>	/**
876	>	* Returns the value to which the specified key is mapped,
877	>	* or {@code null} if this map contains no mapping for the key.
878	>	*
879	>	* <p>More formally, if this map contains a mapping from a key
880	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
881	>	* then this method returns {@code v}; otherwise it returns
882	>	* {@code null}.  (There can be at most one such mapping.)
883	>	*
884	>	* @throws NullPointerException if the specified key is null
885	>	*/
886	>	public V get(Object key) {
887	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
888	>	int h = spread(key.hashCode());
889	>	if ((tab = table) != null && (n = tab.length) > 0 &&
890	>	(e = tabAt(tab, (n - 1) & h)) != null) {
891	>	if ((eh = e.hash) == h) {
892	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
893	>	return e.val;
894	>	}
895	>	else if (eh < 0)
896	>	return (p = e.find(h, key)) != null ? p.val : null;
897	>	while ((e = e.next) != null) {
898	>	if (e.hash == h &&
899	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
900	>	return e.val;
901		}
902		}
903	+	return null;
904	+	}
905
906	<	V replace(K key, int hash, V newValue) {
907	<	lock();
908	<	try {
909	<	HashEntry<K,V> e = getFirst(hash);
910	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
911	<	e = e.next;
912	<
913	<	V oldValue = null;
914	<	if (e != null) {
915	<	oldValue = e.value;
916	<	e.value = newValue;
917	<	}
918	<	return oldValue;
919	<	} finally {
920	<	unlock();
906	>	/**
907	>	* Tests if the specified object is a key in this table.
908	>	*
909	>	* @param  key possible key
910	>	* @return {@code true} if and only if the specified object
911	>	*         is a key in this table, as determined by the
912	>	*         {@code equals} method; {@code false} otherwise
913	>	* @throws NullPointerException if the specified key is null
914	>	*/
915	>	public boolean containsKey(Object key) {
916	>	return get(key) != null;
917	>	}
918	>
919	>	/**
920	>	* Returns {@code true} if this map maps one or more keys to the
921	>	* specified value. Note: This method may require a full traversal
922	>	* of the map, and is much slower than method {@code containsKey}.
923	>	*
924	>	* @param value value whose presence in this map is to be tested
925	>	* @return {@code true} if this map maps one or more keys to the
926	>	*         specified value
927	>	* @throws NullPointerException if the specified value is null
928	>	*/
929	>	public boolean containsValue(Object value) {
930	>	if (value == null)
931	>	throw new NullPointerException();
932	>	Node<K,V>[] t;
933	>	if ((t = table) != null) {
934	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
935	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
936	>	V v;
937	>	if ((v = p.val) == value || (v != null && value.equals(v)))
938	>	return true;
939		}
940		}
941	+	return false;
942	+	}
943
944	+	/**
945	+	* Maps the specified key to the specified value in this table.
946	+	* Neither the key nor the value can be null.
947	+	*
948	+	* <p>The value can be retrieved by calling the {@code get} method
949	+	* with a key that is equal to the original key.
950	+	*
951	+	* @param key key with which the specified value is to be associated
952	+	* @param value value to be associated with the specified key
953	+	* @return the previous value associated with {@code key}, or
954	+	*         {@code null} if there was no mapping for {@code key}
955	+	* @throws NullPointerException if the specified key or value is null
956	+	*/
957	+	public V put(K key, V value) {
958	+	return putVal(key, value, false);
959	+	}
960
961	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
962	<	lock();
963	<	try {
964	<	int c = count;
965	<	if (c++ > threshold) // ensure capacity
966	<	rehash();
967	<	HashEntry<K,V>[] tab = table;
968	<	int index = hash & (tab.length - 1);
969	<	HashEntry<K,V> first = tab[index];
970	<	HashEntry<K,V> e = first;
971	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
972	<	e = e.next;
973	<
974	<	V oldValue;
975	<	if (e != null) {
976	<	oldValue = e.value;
977	<	if (!onlyIfAbsent)
978	<	e.value = value;
961	>	/** Implementation for put and putIfAbsent */
962	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
963	>	if (key == null || value == null) throw new NullPointerException();
964	>	int hash = spread(key.hashCode());
965	>	int binCount = 0;
966	>	for (Node<K,V>[] tab = table;;) {
967	>	Node<K,V> f; int n, i, fh;
968	>	if (tab == null || (n = tab.length) == 0)
969	>	tab = initTable();
970	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
971	>	if (casTabAt(tab, i, null,
972	>	new Node<K,V>(hash, key, value, null)))
973	>	break;                   // no lock when adding to empty bin
974	>	}
975	>	else if ((fh = f.hash) == MOVED)
976	>	tab = helpTransfer(tab, f);
977	>	else {
978	>	V oldVal = null;
979	>	synchronized (f) {
980	>	if (tabAt(tab, i) == f) {
981	>	if (fh >= 0) {
982	>	binCount = 1;
983	>	for (Node<K,V> e = f;; ++binCount) {
984	>	K ek;
985	>	if (e.hash == hash &&
986	>	((ek = e.key) == key ||
987	>	(ek != null && key.equals(ek)))) {
988	>	oldVal = e.val;
989	>	if (!onlyIfAbsent)
990	>	e.val = value;
991	>	break;
992	>	}
993	>	Node<K,V> pred = e;
994	>	if ((e = e.next) == null) {
995	>	pred.next = new Node<K,V>(hash, key,
996	>	value, null);
997	>	break;
998	>	}
999	>	}
1000	>	}
1001	>	else if (f instanceof TreeBin) {
1002	>	Node<K,V> p;
1003	>	binCount = 2;
1004	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1005	>	value)) != null) {
1006	>	oldVal = p.val;
1007	>	if (!onlyIfAbsent)
1008	>	p.val = value;
1009	>	}
1010	>	}
1011	>	}
1012		}
1013	<	else {
1014	<	oldValue = null;
1015	<	++modCount;
1016	<	tab[index] = new HashEntry<K,V>(key, hash, first, value);
1017	<	count = c; // write-volatile
1013	>	if (binCount != 0) {
1014	>	if (binCount >= TREEIFY_THRESHOLD)
1015	>	treeifyBin(tab, i);
1016	>	if (oldVal != null)
1017	>	return oldVal;
1018	>	break;
1019		}
440	–	return oldValue;
441	–	} finally {
442	–	unlock();
1020		}
1021		}
1022	+	addCount(1L, binCount);
1023	+	return null;
1024	+	}
1025
1026	<	void rehash() {
1027	<	HashEntry<K,V>[] oldTable = table;
1028	<	int oldCapacity = oldTable.length;
1029	<	if (oldCapacity >= MAXIMUM_CAPACITY)
1030	<	return;
1026	>	/**
1027	>	* Copies all of the mappings from the specified map to this one.
1028	>	* These mappings replace any mappings that this map had for any of the
1029	>	* keys currently in the specified map.
1030	>	*
1031	>	* @param m mappings to be stored in this map
1032	>	*/
1033	>	public void putAll(Map<? extends K, ? extends V> m) {
1034	>	tryPresize(m.size());
1035	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1036	>	putVal(e.getKey(), e.getValue(), false);
1037	>	}
1038
1039	<	/*
1040	<	* Reclassify nodes in each list to new Map.  Because we are
1041	<	* using power-of-two expansion, the elements from each bin
1042	<	* must either stay at same index, or move with a power of two
1043	<	* offset. We eliminate unnecessary node creation by catching
1044	<	* cases where old nodes can be reused because their next
1045	<	* fields won't change. Statistically, at the default
1046	<	* threshold, only about one-sixth of them need cloning when
1047	<	* a table doubles. The nodes they replace will be garbage
1048	<	* collectable as soon as they are no longer referenced by any
1049	<	* reader thread that may be in the midst of traversing table
1050	<	* right now.
464	<	*/
465	<
466	<	HashEntry<K,V>[] newTable = HashEntry.newArray(oldCapacity<<1);
467	<	threshold = (int)(newTable.length * loadFactor);
468	<	int sizeMask = newTable.length - 1;
469	<	for (int i = 0; i < oldCapacity ; i++) {
470	<	// We need to guarantee that any existing reads of old Map can
471	<	//  proceed. So we cannot yet null out each bin.
472	<	HashEntry<K,V> e = oldTable[i];
473	<
474	<	if (e != null) {
475	<	HashEntry<K,V> next = e.next;
476	<	int idx = e.hash & sizeMask;
477	<
478	<	//  Single node on list
479	<	if (next == null)
480	<	newTable[idx] = e;
1039	>	/**
1040	>	* Removes the key (and its corresponding value) from this map.
1041	>	* This method does nothing if the key is not in the map.
1042	>	*
1043	>	* @param  key the key that needs to be removed
1044	>	* @return the previous value associated with {@code key}, or
1045	>	*         {@code null} if there was no mapping for {@code key}
1046	>	* @throws NullPointerException if the specified key is null
1047	>	*/
1048	>	public V remove(Object key) {
1049	>	return replaceNode(key, null, null);
1050	>	}
1051
1052	<	else {
1053	<	// Reuse trailing consecutive sequence at same slot
1054	<	HashEntry<K,V> lastRun = e;
1055	<	int lastIdx = idx;
1056	<	for (HashEntry<K,V> last = next;
1057	<	last != null;
1058	<	last = last.next) {
1059	<	int k = last.hash & sizeMask;
1060	<	if (k != lastIdx) {
1061	<	lastIdx = k;
1062	<	lastRun = last;
1052	>	/**
1053	>	* Implementation for the four public remove/replace methods:
1054	>	* Replaces node value with v, conditional upon match of cv if
1055	>	* non-null.  If resulting value is null, delete.
1056	>	*/
1057	>	final V replaceNode(Object key, V value, Object cv) {
1058	>	int hash = spread(key.hashCode());
1059	>	for (Node<K,V>[] tab = table;;) {
1060	>	Node<K,V> f; int n, i, fh;
1061	>	if (tab == null || (n = tab.length) == 0 ||
1062	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1063	>	break;
1064	>	else if ((fh = f.hash) == MOVED)
1065	>	tab = helpTransfer(tab, f);
1066	>	else {
1067	>	V oldVal = null;
1068	>	boolean validated = false;
1069	>	synchronized (f) {
1070	>	if (tabAt(tab, i) == f) {
1071	>	if (fh >= 0) {
1072	>	validated = true;
1073	>	for (Node<K,V> e = f, pred = null;;) {
1074	>	K ek;
1075	>	if (e.hash == hash &&
1076	>	((ek = e.key) == key ||
1077	>	(ek != null && key.equals(ek)))) {
1078	>	V ev = e.val;
1079	>	if (cv == null || cv == ev ||
1080	>	(ev != null && cv.equals(ev))) {
1081	>	oldVal = ev;
1082	>	if (value != null)
1083	>	e.val = value;
1084	>	else if (pred != null)
1085	>	pred.next = e.next;
1086	>	else
1087	>	setTabAt(tab, i, e.next);
1088	>	}
1089	>	break;
1090	>	}
1091	>	pred = e;
1092	>	if ((e = e.next) == null)
1093	>	break;
1094		}
1095		}
1096	<	newTable[lastIdx] = lastRun;
1097	<
1098	<	// Clone all remaining nodes
1099	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1100	<	int k = p.hash & sizeMask;
1101	<	HashEntry<K,V> n = newTable[k];
1102	<	newTable[k] = new HashEntry<K,V>(p.key, p.hash,
1103	<	n, p.value);
1096	>	else if (f instanceof TreeBin) {
1097	>	validated = true;
1098	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1099	>	TreeNode<K,V> r, p;
1100	>	if ((r = t.root) != null &&
1101	>	(p = r.findTreeNode(hash, key, null)) != null) {
1102	>	V pv = p.val;
1103	>	if (cv == null || cv == pv ||
1104	>	(pv != null && cv.equals(pv))) {
1105	>	oldVal = pv;
1106	>	if (value != null)
1107	>	p.val = value;
1108	>	else if (t.removeTreeNode(p))
1109	>	setTabAt(tab, i, untreeify(t.first));
1110	>	}
1111	>	}
1112		}
1113		}
1114		}
1115	<	}
1116	<	table = newTable;
1117	<	}
1118	<
1119	<	/**
511	<	* Remove; match on key only if value null, else match both.
512	<	*/
513	<	V remove(Object key, int hash, Object value) {
514	<	lock();
515	<	try {
516	<	int c = count - 1;
517	<	HashEntry<K,V>[] tab = table;
518	<	int index = hash & (tab.length - 1);
519	<	HashEntry<K,V> first = tab[index];
520	<	HashEntry<K,V> e = first;
521	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
522	<	e = e.next;
523	<
524	<	V oldValue = null;
525	<	if (e != null) {
526	<	V v = e.value;
527	<	if (value == null || value.equals(v)) {
528	<	oldValue = v;
529	<	// All entries following removed node can stay
530	<	// in list, but all preceding ones need to be
531	<	// cloned.
532	<	++modCount;
533	<	HashEntry<K,V> newFirst = e.next;
534	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
535	<	newFirst = new HashEntry<K,V>(p.key, p.hash,
536	<	newFirst, p.value);
537	<	tab[index] = newFirst;
538	<	count = c; // write-volatile
1115	>	if (validated) {
1116	>	if (oldVal != null) {
1117	>	if (value == null)
1118	>	addCount(-1L, -1);
1119	>	return oldVal;
1120		}
1121	+	break;
1122		}
541	–	return oldValue;
542	–	} finally {
543	–	unlock();
1123		}
1124		}
1125	+	return null;
1126	+	}
1127
1128	<	void clear() {
1129	<	if (count != 0) {
1130	<	lock();
1131	<	try {
1132	<	HashEntry<K,V>[] tab = table;
1133	<	for (int i = 0; i < tab.length ; i++)
1134	<	tab[i] = null;
1135	<	++modCount;
1136	<	count = 0; // write-volatile
1137	<	} finally {
1138	<	unlock();
1128	>	/**
1129	>	* Removes all of the mappings from this map.
1130	>	*/
1131	>	public void clear() {
1132	>	long delta = 0L; // negative number of deletions
1133	>	int i = 0;
1134	>	Node<K,V>[] tab = table;
1135	>	while (tab != null && i < tab.length) {
1136	>	int fh;
1137	>	Node<K,V> f = tabAt(tab, i);
1138	>	if (f == null)
1139	>	++i;
1140	>	else if ((fh = f.hash) == MOVED) {
1141	>	tab = helpTransfer(tab, f);
1142	>	i = 0; // restart
1143	>	}
1144	>	else {
1145	>	synchronized (f) {
1146	>	if (tabAt(tab, i) == f) {
1147	>	Node<K,V> p = (fh >= 0 ? f :
1148	>	(f instanceof TreeBin) ?
1149	>	((TreeBin<K,V>)f).first : null);
1150	>	while (p != null) {
1151	>	--delta;
1152	>	p = p.next;
1153	>	}
1154	>	setTabAt(tab, i++, null);
1155	>	}
1156		}
1157		}
1158		}
1159	+	if (delta != 0L)
1160	+	addCount(delta, -1);
1161		}
1162
563	–
564	–
565	–	/* ---------------- Public operations -------------- */
566	–
1163		/**
1164	<	* Creates a new, empty map with the specified initial
1165	<	* capacity, load factor and concurrency level.
1164	>	* Returns a {@link Set} view of the keys contained in this map.
1165	>	* The set is backed by the map, so changes to the map are
1166	>	* reflected in the set, and vice-versa. The set supports element
1167	>	* removal, which removes the corresponding mapping from this map,
1168	>	* via the {@code Iterator.remove}, {@code Set.remove},
1169	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1170	>	* operations.  It does not support the {@code add} or
1171	>	* {@code addAll} operations.
1172		*
1173	<	* @param initialCapacity the initial capacity. The implementation
1174	<	* performs internal sizing to accommodate this many elements.
1175	<	* @param loadFactor  the load factor threshold, used to control resizing.
1176	<	* Resizing may be performed when the average number of elements per
1177	<	* bin exceeds this threshold.
1178	<	* @param concurrencyLevel the estimated number of concurrently
1179	<	* updating threads. The implementation performs internal sizing
578	<	* to try to accommodate this many threads.
579	<	* @throws IllegalArgumentException if the initial capacity is
580	<	* negative or the load factor or concurrencyLevel are
581	<	* nonpositive.
1173	>	* <p>The view's iterators and spliterators are
1174	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1175	>	*
1176	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1177	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1178	>	*
1179	>	* @return the set view
1180		*/
1181	<	public ConcurrentHashMap(int initialCapacity,
1182	<	float loadFactor, int concurrencyLevel) {
1183	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
586	<	throw new IllegalArgumentException();
587	<
588	<	if (concurrencyLevel > MAX_SEGMENTS)
589	<	concurrencyLevel = MAX_SEGMENTS;
590	<
591	<	// Find power-of-two sizes best matching arguments
592	<	int sshift = 0;
593	<	int ssize = 1;
594	<	while (ssize < concurrencyLevel) {
595	<	++sshift;
596	<	ssize <<= 1;
597	<	}
598	<	segmentShift = 32 - sshift;
599	<	segmentMask = ssize - 1;
600	<	this.segments = Segment.newArray(ssize);
601	<
602	<	if (initialCapacity > MAXIMUM_CAPACITY)
603	<	initialCapacity = MAXIMUM_CAPACITY;
604	<	int c = initialCapacity / ssize;
605	<	if (c * ssize < initialCapacity)
606	<	++c;
607	<	int cap = 1;
608	<	while (cap < c)
609	<	cap <<= 1;
610	<
611	<	for (int i = 0; i < this.segments.length; ++i)
612	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
1181	>	public KeySetView<K,V> keySet() {
1182	>	KeySetView<K,V> ks;
1183	>	return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1184		}
1185
1186		/**
1187	<	* Creates a new, empty map with the specified initial capacity
1188	<	* and load factor and with the default concurrencyLevel (16).
1187	>	* Returns a {@link Collection} view of the values contained in this map.
1188	>	* The collection is backed by the map, so changes to the map are
1189	>	* reflected in the collection, and vice-versa.  The collection
1190	>	* supports element removal, which removes the corresponding
1191	>	* mapping from this map, via the {@code Iterator.remove},
1192	>	* {@code Collection.remove}, {@code removeAll},
1193	>	* {@code retainAll}, and {@code clear} operations.  It does not
1194	>	* support the {@code add} or {@code addAll} operations.
1195		*
1196	<	* @param initialCapacity The implementation performs internal
1197	<	* sizing to accommodate this many elements.
621	<	* @param loadFactor  the load factor threshold, used to control resizing.
622	<	* Resizing may be performed when the average number of elements per
623	<	* bin exceeds this threshold.
624	<	* @throws IllegalArgumentException if the initial capacity of
625	<	* elements is negative or the load factor is nonpositive
1196	>	* <p>The view's iterators and spliterators are
1197	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1198		*
1199	<	* @since 1.6
1199	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1200	>	* and {@link Spliterator#NONNULL}.
1201	>	*
1202	>	* @return the collection view
1203		*/
1204	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
1205	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1204	>	public Collection<V> values() {
1205	>	ValuesView<K,V> vs;
1206	>	return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1207		}
1208
1209		/**
1210	<	* Creates a new, empty map with the specified initial capacity,
1211	<	* and with default load factor (0.75) and concurrencyLevel (16).
1210	>	* Returns a {@link Set} view of the mappings contained in this map.
1211	>	* The set is backed by the map, so changes to the map are
1212	>	* reflected in the set, and vice-versa.  The set supports element
1213	>	* removal, which removes the corresponding mapping from the map,
1214	>	* via the {@code Iterator.remove}, {@code Set.remove},
1215	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1216	>	* operations.
1217		*
1218	<	* @param initialCapacity the initial capacity. The implementation
1219	<	* performs internal sizing to accommodate this many elements.
1220	<	* @throws IllegalArgumentException if the initial capacity of
1221	<	* elements is negative.
1218	>	* <p>The view's iterators and spliterators are
1219	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1220	>	*
1221	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1222	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1223	>	*
1224	>	* @return the set view
1225		*/
1226	<	public ConcurrentHashMap(int initialCapacity) {
1227	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1226	>	public Set<Map.Entry<K,V>> entrySet() {
1227	>	EntrySetView<K,V> es;
1228	>	return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1229		}
1230
1231		/**
1232	<	* Creates a new, empty map with a default initial capacity (16),
1233	<	* load factor (0.75) and concurrencyLevel (16).
1232	>	* Returns the hash code value for this {@link Map}, i.e.,
1233	>	* the sum of, for each key-value pair in the map,
1234	>	* {@code key.hashCode() ^ value.hashCode()}.
1235	>	*
1236	>	* @return the hash code value for this map
1237		*/
1238	<	public ConcurrentHashMap() {
1239	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1238	>	public int hashCode() {
1239	>	int h = 0;
1240	>	Node<K,V>[] t;
1241	>	if ((t = table) != null) {
1242	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1243	>	for (Node<K,V> p; (p = it.advance()) != null; )
1244	>	h += p.key.hashCode() ^ p.val.hashCode();
1245	>	}
1246	>	return h;
1247		}
1248
1249		/**
1250	<	* Creates a new map with the same mappings as the given map.
1251	<	* The map is created with a capacity of 1.5 times the number
1252	<	* of mappings in the given map or 16 (whichever is greater),
1253	<	* and a default load factor (0.75) and concurrencyLevel (16).
1250	>	* Returns a string representation of this map.  The string
1251	>	* representation consists of a list of key-value mappings (in no
1252	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1253	>	* mappings are separated by the characters {@code ", "} (comma
1254	>	* and space).  Each key-value mapping is rendered as the key
1255	>	* followed by an equals sign ("{@code =}") followed by the
1256	>	* associated value.
1257		*
1258	<	* @param m the map
1258	>	* @return a string representation of this map
1259		*/
1260	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
1261	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
1262	<	DEFAULT_INITIAL_CAPACITY),
1263	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1264	<	putAll(m);
1260	>	public String toString() {
1261	>	Node<K,V>[] t;
1262	>	int f = (t = table) == null ? 0 : t.length;
1263	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1264	>	StringBuilder sb = new StringBuilder();
1265	>	sb.append('{');
1266	>	Node<K,V> p;
1267	>	if ((p = it.advance()) != null) {
1268	>	for (;;) {
1269	>	K k = p.key;
1270	>	V v = p.val;
1271	>	sb.append(k == this ? "(this Map)" : k);
1272	>	sb.append('=');
1273	>	sb.append(v == this ? "(this Map)" : v);
1274	>	if ((p = it.advance()) == null)
1275	>	break;
1276	>	sb.append(',').append(' ');
1277	>	}
1278	>	}
1279	>	return sb.append('}').toString();
1280		}
1281
1282		/**
1283	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
1283	>	* Compares the specified object with this map for equality.
1284	>	* Returns {@code true} if the given object is a map with the same
1285	>	* mappings as this map.  This operation may return misleading
1286	>	* results if either map is concurrently modified during execution
1287	>	* of this method.
1288		*
1289	<	* @return <tt>true</tt> if this map contains no key-value mappings
1289	>	* @param o object to be compared for equality with this map
1290	>	* @return {@code true} if the specified object is equal to this map
1291		*/
1292	<	public boolean isEmpty() {
1293	<	final Segment<K,V>[] segments = this.segments;
1294	<	/*
677	<	* We keep track of per-segment modCounts to avoid ABA
678	<	* problems in which an element in one segment was added and
679	<	* in another removed during traversal, in which case the
680	<	* table was never actually empty at any point. Note the
681	<	* similar use of modCounts in the size() and containsValue()
682	<	* methods, which are the only other methods also susceptible
683	<	* to ABA problems.
684	<	*/
685	<	int[] mc = new int[segments.length];
686	<	int mcsum = 0;
687	<	for (int i = 0; i < segments.length; ++i) {
688	<	if (segments[i].count != 0)
1292	>	public boolean equals(Object o) {
1293	>	if (o != this) {
1294	>	if (!(o instanceof Map))
1295		return false;
1296	<	else
1297	<	mcsum += mc[i] = segments[i].modCount;
1298	<	}
1299	<	// If mcsum happens to be zero, then we know we got a snapshot
1300	<	// before any modifications at all were made.  This is
1301	<	// probably common enough to bother tracking.
1302	<	if (mcsum != 0) {
1303	<	for (int i = 0; i < segments.length; ++i) {
1304	<	if (segments[i].count != 0 ||
1305	<	mc[i] != segments[i].modCount)
1296	>	Map<?,?> m = (Map<?,?>) o;
1297	>	Node<K,V>[] t;
1298	>	int f = (t = table) == null ? 0 : t.length;
1299	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1300	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1301	>	V val = p.val;
1302	>	Object v = m.get(p.key);
1303	>	if (v == null || (v != val && !v.equals(val)))
1304	>	return false;
1305	>	}
1306	>	for (Map.Entry<?,?> e : m.entrySet()) {
1307	>	Object mk, mv, v;
1308	>	if ((mk = e.getKey()) == null ||
1309	>	(mv = e.getValue()) == null ||
1310	>	(v = get(mk)) == null ||
1311	>	(mv != v && !mv.equals(v)))
1312		return false;
1313		}
1314		}
#	Line 704 | Line 1316 | public class ConcurrentHashMap<K, V> ext
1316		}
1317
1318		/**
1319	<	* Returns the number of key-value mappings in this map.  If the
1320	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
709	<	* <tt>Integer.MAX_VALUE</tt>.
710	<	*
711	<	* @return the number of key-value mappings in this map
1319	>	* Stripped-down version of helper class used in previous version,
1320	>	* declared for the sake of serialization compatibility
1321		*/
1322	<	public int size() {
1323	<	final Segment<K,V>[] segments = this.segments;
1324	<	long sum = 0;
1325	<	long check = 0;
1326	<	int[] mc = new int[segments.length];
1327	<	// Try a few times to get accurate count. On failure due to
1328	<	// continuous async changes in table, resort to locking.
1329	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1330	<	check = 0;
1331	<	sum = 0;
1332	<	int mcsum = 0;
1333	<	for (int i = 0; i < segments.length; ++i) {
1334	<	sum += segments[i].count;
1335	<	mcsum += mc[i] = segments[i].modCount;
1336	<	}
1337	<	if (mcsum != 0) {
1338	<	for (int i = 0; i < segments.length; ++i) {
1339	<	check += segments[i].count;
1340	<	if (mc[i] != segments[i].modCount) {
1341	<	check = -1; // force retry
1342	<	break;
1322	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1323	>	private static final long serialVersionUID = 2249069246763182397L;
1324	>	final float loadFactor;
1325	>	Segment(float lf) { this.loadFactor = lf; }
1326	>	}
1327	>
1328	>	/**
1329	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1330	>	* stream (i.e., serializes it).
1331	>	* @param s the stream
1332	>	* @throws java.io.IOException if an I/O error occurs
1333	>	* @serialData
1334	>	* the key (Object) and value (Object)
1335	>	* for each key-value mapping, followed by a null pair.
1336	>	* The key-value mappings are emitted in no particular order.
1337	>	*/
1338	>	private void writeObject(java.io.ObjectOutputStream s)
1339	>	throws java.io.IOException {
1340	>	// For serialization compatibility
1341	>	// Emulate segment calculation from previous version of this class
1342	>	int sshift = 0;
1343	>	int ssize = 1;
1344	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1345	>	++sshift;
1346	>	ssize <<= 1;
1347	>	}
1348	>	int segmentShift = 32 - sshift;
1349	>	int segmentMask = ssize - 1;
1350	>	@SuppressWarnings("unchecked")
1351	>	Segment<K,V>[] segments = (Segment<K,V>[])
1352	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1353	>	for (int i = 0; i < segments.length; ++i)
1354	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1355	>	s.putFields().put("segments", segments);
1356	>	s.putFields().put("segmentShift", segmentShift);
1357	>	s.putFields().put("segmentMask", segmentMask);
1358	>	s.writeFields();
1359	>
1360	>	Node<K,V>[] t;
1361	>	if ((t = table) != null) {
1362	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1363	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1364	>	s.writeObject(p.key);
1365	>	s.writeObject(p.val);
1366	>	}
1367	>	}
1368	>	s.writeObject(null);
1369	>	s.writeObject(null);
1370	>	segments = null; // throw away
1371	>	}
1372	>
1373	>	/**
1374	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1375	>	* @param s the stream
1376	>	* @throws ClassNotFoundException if the class of a serialized object
1377	>	*         could not be found
1378	>	* @throws java.io.IOException if an I/O error occurs
1379	>	*/
1380	>	private void readObject(java.io.ObjectInputStream s)
1381	>	throws java.io.IOException, ClassNotFoundException {
1382	>	/*
1383	>	* To improve performance in typical cases, we create nodes
1384	>	* while reading, then place in table once size is known.
1385	>	* However, we must also validate uniqueness and deal with
1386	>	* overpopulated bins while doing so, which requires
1387	>	* specialized versions of putVal mechanics.
1388	>	*/
1389	>	sizeCtl = -1; // force exclusion for table construction
1390	>	s.defaultReadObject();
1391	>	long size = 0L;
1392	>	Node<K,V> p = null;
1393	>	for (;;) {
1394	>	@SuppressWarnings("unchecked")
1395	>	K k = (K) s.readObject();
1396	>	@SuppressWarnings("unchecked")
1397	>	V v = (V) s.readObject();
1398	>	if (k != null && v != null) {
1399	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1400	>	++size;
1401	>	}
1402	>	else
1403	>	break;
1404	>	}
1405	>	if (size == 0L)
1406	>	sizeCtl = 0;
1407	>	else {
1408	>	int n;
1409	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1410	>	n = MAXIMUM_CAPACITY;
1411	>	else {
1412	>	int sz = (int)size;
1413	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1414	>	}
1415	>	@SuppressWarnings("unchecked")
1416	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1417	>	int mask = n - 1;
1418	>	long added = 0L;
1419	>	while (p != null) {
1420	>	boolean insertAtFront;
1421	>	Node<K,V> next = p.next, first;
1422	>	int h = p.hash, j = h & mask;
1423	>	if ((first = tabAt(tab, j)) == null)
1424	>	insertAtFront = true;
1425	>	else {
1426	>	K k = p.key;
1427	>	if (first.hash < 0) {
1428	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1429	>	if (t.putTreeVal(h, k, p.val) == null)
1430	>	++added;
1431	>	insertAtFront = false;
1432		}
1433	+	else {
1434	+	int binCount = 0;
1435	+	insertAtFront = true;
1436	+	Node<K,V> q; K qk;
1437	+	for (q = first; q != null; q = q.next) {
1438	+	if (q.hash == h &&
1439	+	((qk = q.key) == k ||
1440	+	(qk != null && k.equals(qk)))) {
1441	+	insertAtFront = false;
1442	+	break;
1443	+	}
1444	+	++binCount;
1445	+	}
1446	+	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1447	+	insertAtFront = false;
1448	+	++added;
1449	+	p.next = first;
1450	+	TreeNode<K,V> hd = null, tl = null;
1451	+	for (q = p; q != null; q = q.next) {
1452	+	TreeNode<K,V> t = new TreeNode<K,V>
1453	+	(q.hash, q.key, q.val, null, null);
1454	+	if ((t.prev = tl) == null)
1455	+	hd = t;
1456	+	else
1457	+	tl.next = t;
1458	+	tl = t;
1459	+	}
1460	+	setTabAt(tab, j, new TreeBin<K,V>(hd));
1461	+	}
1462	+	}
1463	+	}
1464	+	if (insertAtFront) {
1465	+	++added;
1466	+	p.next = first;
1467	+	setTabAt(tab, j, p);
1468		}
1469	+	p = next;
1470		}
1471	<	if (check == sum)
1472	<	break;
1471	>	table = tab;
1472	>	sizeCtl = n - (n >>> 2);
1473	>	baseCount = added;
1474		}
740	–	if (check != sum) { // Resort to locking all segments
741	–	sum = 0;
742	–	for (int i = 0; i < segments.length; ++i)
743	–	segments[i].lock();
744	–	for (int i = 0; i < segments.length; ++i)
745	–	sum += segments[i].count;
746	–	for (int i = 0; i < segments.length; ++i)
747	–	segments[i].unlock();
748	–	}
749	–	if (sum > Integer.MAX_VALUE)
750	–	return Integer.MAX_VALUE;
751	–	else
752	–	return (int)sum;
1475		}
1476
1477	+	// ConcurrentMap methods
1478	+
1479		/**
1480	<	* Returns the value to which the specified key is mapped,
757	<	* or {@code null} if this map contains no mapping for the key.
1480	>	* {@inheritDoc}
1481		*
1482	<	* <p>More formally, if this map contains a mapping from a key
1483	<	* {@code k} to a value {@code v} such that {@code key.equals(k)},
1484	<	* then this method returns {@code v}; otherwise it returns
1485	<	* {@code null}.  (There can be at most one such mapping.)
1482	>	* @return the previous value associated with the specified key,
1483	>	*         or {@code null} if there was no mapping for the key
1484	>	* @throws NullPointerException if the specified key or value is null
1485	>	*/
1486	>	public V putIfAbsent(K key, V value) {
1487	>	return putVal(key, value, true);
1488	>	}
1489	>
1490	>	/**
1491	>	* {@inheritDoc}
1492		*
1493		* @throws NullPointerException if the specified key is null
1494		*/
1495	<	public V get(Object key) {
1496	<	int hash = hash(key.hashCode());
1497	<	return segmentFor(hash).get(key, hash);
1495	>	public boolean remove(Object key, Object value) {
1496	>	if (key == null)
1497	>	throw new NullPointerException();
1498	>	return value != null && replaceNode(key, null, value) != null;
1499		}
1500
1501		/**
1502	<	* Tests if the specified object is a key in this table.
1502	>	* {@inheritDoc}
1503		*
1504	<	* @param  key   possible key
775	<	* @return <tt>true</tt> if and only if the specified object
776	<	*         is a key in this table, as determined by the
777	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
778	<	* @throws NullPointerException if the specified key is null
1504	>	* @throws NullPointerException if any of the arguments are null
1505		*/
1506	<	public boolean containsKey(Object key) {
1507	<	int hash = hash(key.hashCode());
1508	<	return segmentFor(hash).containsKey(key, hash);
1506	>	public boolean replace(K key, V oldValue, V newValue) {
1507	>	if (key == null || oldValue == null || newValue == null)
1508	>	throw new NullPointerException();
1509	>	return replaceNode(key, newValue, oldValue) != null;
1510		}
1511
1512		/**
1513	<	* Returns <tt>true</tt> if this map maps one or more keys to the
787	<	* specified value. Note: This method requires a full internal
788	<	* traversal of the hash table, and so is much slower than
789	<	* method <tt>containsKey</tt>.
1513	>	* {@inheritDoc}
1514		*
1515	<	* @param value value whose presence in this map is to be tested
1516	<	* @return <tt>true</tt> if this map maps one or more keys to the
1517	<	*         specified value
794	<	* @throws NullPointerException if the specified value is null
1515	>	* @return the previous value associated with the specified key,
1516	>	*         or {@code null} if there was no mapping for the key
1517	>	* @throws NullPointerException if the specified key or value is null
1518		*/
1519	<	public boolean containsValue(Object value) {
1520	<	if (value == null)
1519	>	public V replace(K key, V value) {
1520	>	if (key == null || value == null)
1521		throw new NullPointerException();
1522	+	return replaceNode(key, value, null);
1523	+	}
1524
1525	<	// See explanation of modCount use above
1525	>	// Overrides of JDK8+ Map extension method defaults
1526
1527	<	final Segment<K,V>[] segments = this.segments;
1528	<	int[] mc = new int[segments.length];
1527	>	/**
1528	>	* Returns the value to which the specified key is mapped, or the
1529	>	* given default value if this map contains no mapping for the
1530	>	* key.
1531	>	*
1532	>	* @param key the key whose associated value is to be returned
1533	>	* @param defaultValue the value to return if this map contains
1534	>	* no mapping for the given key
1535	>	* @return the mapping for the key, if present; else the default value
1536	>	* @throws NullPointerException if the specified key is null
1537	>	*/
1538	>	public V getOrDefault(Object key, V defaultValue) {
1539	>	V v;
1540	>	return (v = get(key)) == null ? defaultValue : v;
1541	>	}
1542
1543	<	// Try a few times without locking
1544	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1545	<	int sum = 0;
1546	<	int mcsum = 0;
1547	<	for (int i = 0; i < segments.length; ++i) {
1548	<	int c = segments[i].count;
1549	<	mcsum += mc[i] = segments[i].modCount;
812	<	if (segments[i].containsValue(value))
813	<	return true;
1543	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1544	>	if (action == null) throw new NullPointerException();
1545	>	Node<K,V>[] t;
1546	>	if ((t = table) != null) {
1547	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1548	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1549	>	action.accept(p.key, p.val);
1550		}
1551	<	boolean cleanSweep = true;
1552	<	if (mcsum != 0) {
1553	<	for (int i = 0; i < segments.length; ++i) {
1554	<	int c = segments[i].count;
1555	<	if (mc[i] != segments[i].modCount) {
1556	<	cleanSweep = false;
1551	>	}
1552	>	}
1553	>
1554	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1555	>	if (function == null) throw new NullPointerException();
1556	>	Node<K,V>[] t;
1557	>	if ((t = table) != null) {
1558	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1559	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1560	>	V oldValue = p.val;
1561	>	for (K key = p.key;;) {
1562	>	V newValue = function.apply(key, oldValue);
1563	>	if (newValue == null)
1564	>	throw new NullPointerException();
1565	>	if (replaceNode(key, newValue, oldValue) != null ||
1566	>	(oldValue = get(key)) == null)
1567		break;
1568	+	}
1569	+	}
1570	+	}
1571	+	}
1572	+
1573	+	/**
1574	+	* If the specified key is not already associated with a value,
1575	+	* attempts to compute its value using the given mapping function
1576	+	* and enters it into this map unless {@code null}.  The entire
1577	+	* method invocation is performed atomically, so the function is
1578	+	* applied at most once per key.  Some attempted update operations
1579	+	* on this map by other threads may be blocked while computation
1580	+	* is in progress, so the computation should be short and simple,
1581	+	* and must not attempt to update any other mappings of this map.
1582	+	*
1583	+	* @param key key with which the specified value is to be associated
1584	+	* @param mappingFunction the function to compute a value
1585	+	* @return the current (existing or computed) value associated with
1586	+	*         the specified key, or null if the computed value is null
1587	+	* @throws NullPointerException if the specified key or mappingFunction
1588	+	*         is null
1589	+	* @throws IllegalStateException if the computation detectably
1590	+	*         attempts a recursive update to this map that would
1591	+	*         otherwise never complete
1592	+	* @throws RuntimeException or Error if the mappingFunction does so,
1593	+	*         in which case the mapping is left unestablished
1594	+	*/
1595	+	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1596	+	if (key == null || mappingFunction == null)
1597	+	throw new NullPointerException();
1598	+	int h = spread(key.hashCode());
1599	+	V val = null;
1600	+	int binCount = 0;
1601	+	for (Node<K,V>[] tab = table;;) {
1602	+	Node<K,V> f; int n, i, fh;
1603	+	if (tab == null || (n = tab.length) == 0)
1604	+	tab = initTable();
1605	+	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1606	+	Node<K,V> r = new ReservationNode<K,V>();
1607	+	synchronized (r) {
1608	+	if (casTabAt(tab, i, null, r)) {
1609	+	binCount = 1;
1610	+	Node<K,V> node = null;
1611	+	try {
1612	+	if ((val = mappingFunction.apply(key)) != null)
1613	+	node = new Node<K,V>(h, key, val, null);
1614	+	} finally {
1615	+	setTabAt(tab, i, node);
1616	+	}
1617		}
1618		}
1619	+	if (binCount != 0)
1620	+	break;
1621	+	}
1622	+	else if ((fh = f.hash) == MOVED)
1623	+	tab = helpTransfer(tab, f);
1624	+	else {
1625	+	boolean added = false;
1626	+	synchronized (f) {
1627	+	if (tabAt(tab, i) == f) {
1628	+	if (fh >= 0) {
1629	+	binCount = 1;
1630	+	for (Node<K,V> e = f;; ++binCount) {
1631	+	K ek; V ev;
1632	+	if (e.hash == h &&
1633	+	((ek = e.key) == key ||
1634	+	(ek != null && key.equals(ek)))) {
1635	+	val = e.val;
1636	+	break;
1637	+	}
1638	+	Node<K,V> pred = e;
1639	+	if ((e = e.next) == null) {
1640	+	if ((val = mappingFunction.apply(key)) != null) {
1641	+	added = true;
1642	+	pred.next = new Node<K,V>(h, key, val, null);
1643	+	}
1644	+	break;
1645	+	}
1646	+	}
1647	+	}
1648	+	else if (f instanceof TreeBin) {
1649	+	binCount = 2;
1650	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
1651	+	TreeNode<K,V> r, p;
1652	+	if ((r = t.root) != null &&
1653	+	(p = r.findTreeNode(h, key, null)) != null)
1654	+	val = p.val;
1655	+	else if ((val = mappingFunction.apply(key)) != null) {
1656	+	added = true;
1657	+	t.putTreeVal(h, key, val);
1658	+	}
1659	+	}
1660	+	}
1661	+	}
1662	+	if (binCount != 0) {
1663	+	if (binCount >= TREEIFY_THRESHOLD)
1664	+	treeifyBin(tab, i);
1665	+	if (!added)
1666	+	return val;
1667	+	break;
1668	+	}
1669		}
825	–	if (cleanSweep)
826	–	return false;
1670		}
1671	<	// Resort to locking all segments
1672	<	for (int i = 0; i < segments.length; ++i)
1673	<	segments[i].lock();
1674	<	boolean found = false;
1675	<	try {
1676	<	for (int i = 0; i < segments.length; ++i) {
1677	<	if (segments[i].containsValue(value)) {
1678	<	found = true;
1671	>	if (val != null)
1672	>	addCount(1L, binCount);
1673	>	return val;
1674	>	}
1675	>
1676	>	/**
1677	>	* If the value for the specified key is present, attempts to
1678	>	* compute a new mapping given the key and its current mapped
1679	>	* value.  The entire method invocation is performed atomically.
1680	>	* Some attempted update operations on this map by other threads
1681	>	* may be blocked while computation is in progress, so the
1682	>	* computation should be short and simple, and must not attempt to
1683	>	* update any other mappings of this map.
1684	>	*
1685	>	* @param key key with which a value may be associated
1686	>	* @param remappingFunction the function to compute a value
1687	>	* @return the new value associated with the specified key, or null if none
1688	>	* @throws NullPointerException if the specified key or remappingFunction
1689	>	*         is null
1690	>	* @throws IllegalStateException if the computation detectably
1691	>	*         attempts a recursive update to this map that would
1692	>	*         otherwise never complete
1693	>	* @throws RuntimeException or Error if the remappingFunction does so,
1694	>	*         in which case the mapping is unchanged
1695	>	*/
1696	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1697	>	if (key == null || remappingFunction == null)
1698	>	throw new NullPointerException();
1699	>	int h = spread(key.hashCode());
1700	>	V val = null;
1701	>	int delta = 0;
1702	>	int binCount = 0;
1703	>	for (Node<K,V>[] tab = table;;) {
1704	>	Node<K,V> f; int n, i, fh;
1705	>	if (tab == null || (n = tab.length) == 0)
1706	>	tab = initTable();
1707	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1708	>	break;
1709	>	else if ((fh = f.hash) == MOVED)
1710	>	tab = helpTransfer(tab, f);
1711	>	else {
1712	>	synchronized (f) {
1713	>	if (tabAt(tab, i) == f) {
1714	>	if (fh >= 0) {
1715	>	binCount = 1;
1716	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1717	>	K ek;
1718	>	if (e.hash == h &&
1719	>	((ek = e.key) == key ||
1720	>	(ek != null && key.equals(ek)))) {
1721	>	val = remappingFunction.apply(key, e.val);
1722	>	if (val != null)
1723	>	e.val = val;
1724	>	else {
1725	>	delta = -1;
1726	>	Node<K,V> en = e.next;
1727	>	if (pred != null)
1728	>	pred.next = en;
1729	>	else
1730	>	setTabAt(tab, i, en);
1731	>	}
1732	>	break;
1733	>	}
1734	>	pred = e;
1735	>	if ((e = e.next) == null)
1736	>	break;
1737	>	}
1738	>	}
1739	>	else if (f instanceof TreeBin) {
1740	>	binCount = 2;
1741	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1742	>	TreeNode<K,V> r, p;
1743	>	if ((r = t.root) != null &&
1744	>	(p = r.findTreeNode(h, key, null)) != null) {
1745	>	val = remappingFunction.apply(key, p.val);
1746	>	if (val != null)
1747	>	p.val = val;
1748	>	else {
1749	>	delta = -1;
1750	>	if (t.removeTreeNode(p))
1751	>	setTabAt(tab, i, untreeify(t.first));
1752	>	}
1753	>	}
1754	>	}
1755	>	}
1756	>	}
1757	>	if (binCount != 0)
1758	>	break;
1759	>	}
1760	>	}
1761	>	if (delta != 0)
1762	>	addCount((long)delta, binCount);
1763	>	return val;
1764	>	}
1765	>
1766	>	/**
1767	>	* Attempts to compute a mapping for the specified key and its
1768	>	* current mapped value (or {@code null} if there is no current
1769	>	* mapping). The entire method invocation is performed atomically.
1770	>	* Some attempted update operations on this map by other threads
1771	>	* may be blocked while computation is in progress, so the
1772	>	* computation should be short and simple, and must not attempt to
1773	>	* update any other mappings of this Map.
1774	>	*
1775	>	* @param key key with which the specified value is to be associated
1776	>	* @param remappingFunction the function to compute a value
1777	>	* @return the new value associated with the specified key, or null if none
1778	>	* @throws NullPointerException if the specified key or remappingFunction
1779	>	*         is null
1780	>	* @throws IllegalStateException if the computation detectably
1781	>	*         attempts a recursive update to this map that would
1782	>	*         otherwise never complete
1783	>	* @throws RuntimeException or Error if the remappingFunction does so,
1784	>	*         in which case the mapping is unchanged
1785	>	*/
1786	>	public V compute(K key,
1787	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1788	>	if (key == null || remappingFunction == null)
1789	>	throw new NullPointerException();
1790	>	int h = spread(key.hashCode());
1791	>	V val = null;
1792	>	int delta = 0;
1793	>	int binCount = 0;
1794	>	for (Node<K,V>[] tab = table;;) {
1795	>	Node<K,V> f; int n, i, fh;
1796	>	if (tab == null || (n = tab.length) == 0)
1797	>	tab = initTable();
1798	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1799	>	Node<K,V> r = new ReservationNode<K,V>();
1800	>	synchronized (r) {
1801	>	if (casTabAt(tab, i, null, r)) {
1802	>	binCount = 1;
1803	>	Node<K,V> node = null;
1804	>	try {
1805	>	if ((val = remappingFunction.apply(key, null)) != null) {
1806	>	delta = 1;
1807	>	node = new Node<K,V>(h, key, val, null);
1808	>	}
1809	>	} finally {
1810	>	setTabAt(tab, i, node);
1811	>	}
1812	>	}
1813	>	}
1814	>	if (binCount != 0)
1815	>	break;
1816	>	}
1817	>	else if ((fh = f.hash) == MOVED)
1818	>	tab = helpTransfer(tab, f);
1819	>	else {
1820	>	synchronized (f) {
1821	>	if (tabAt(tab, i) == f) {
1822	>	if (fh >= 0) {
1823	>	binCount = 1;
1824	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1825	>	K ek;
1826	>	if (e.hash == h &&
1827	>	((ek = e.key) == key ||
1828	>	(ek != null && key.equals(ek)))) {
1829	>	val = remappingFunction.apply(key, e.val);
1830	>	if (val != null)
1831	>	e.val = val;
1832	>	else {
1833	>	delta = -1;
1834	>	Node<K,V> en = e.next;
1835	>	if (pred != null)
1836	>	pred.next = en;
1837	>	else
1838	>	setTabAt(tab, i, en);
1839	>	}
1840	>	break;
1841	>	}
1842	>	pred = e;
1843	>	if ((e = e.next) == null) {
1844	>	val = remappingFunction.apply(key, null);
1845	>	if (val != null) {
1846	>	delta = 1;
1847	>	pred.next =
1848	>	new Node<K,V>(h, key, val, null);
1849	>	}
1850	>	break;
1851	>	}
1852	>	}
1853	>	}
1854	>	else if (f instanceof TreeBin) {
1855	>	binCount = 1;
1856	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1857	>	TreeNode<K,V> r, p;
1858	>	if ((r = t.root) != null)
1859	>	p = r.findTreeNode(h, key, null);
1860	>	else
1861	>	p = null;
1862	>	V pv = (p == null) ? null : p.val;
1863	>	val = remappingFunction.apply(key, pv);
1864	>	if (val != null) {
1865	>	if (p != null)
1866	>	p.val = val;
1867	>	else {
1868	>	delta = 1;
1869	>	t.putTreeVal(h, key, val);
1870	>	}
1871	>	}
1872	>	else if (p != null) {
1873	>	delta = -1;
1874	>	if (t.removeTreeNode(p))
1875	>	setTabAt(tab, i, untreeify(t.first));
1876	>	}
1877	>	}
1878	>	}
1879	>	}
1880	>	if (binCount != 0) {
1881	>	if (binCount >= TREEIFY_THRESHOLD)
1882	>	treeifyBin(tab, i);
1883		break;
1884		}
1885		}
839	–	} finally {
840	–	for (int i = 0; i < segments.length; ++i)
841	–	segments[i].unlock();
1886		}
1887	<	return found;
1887	>	if (delta != 0)
1888	>	addCount((long)delta, binCount);
1889	>	return val;
1890		}
1891
1892		/**
1893	+	* If the specified key is not already associated with a
1894	+	* (non-null) value, associates it with the given value.
1895	+	* Otherwise, replaces the value with the results of the given
1896	+	* remapping function, or removes if {@code null}. The entire
1897	+	* method invocation is performed atomically.  Some attempted
1898	+	* update operations on this map by other threads may be blocked
1899	+	* while computation is in progress, so the computation should be
1900	+	* short and simple, and must not attempt to update any other
1901	+	* mappings of this Map.
1902	+	*
1903	+	* @param key key with which the specified value is to be associated
1904	+	* @param value the value to use if absent
1905	+	* @param remappingFunction the function to recompute a value if present
1906	+	* @return the new value associated with the specified key, or null if none
1907	+	* @throws NullPointerException if the specified key or the
1908	+	*         remappingFunction is null
1909	+	* @throws RuntimeException or Error if the remappingFunction does so,
1910	+	*         in which case the mapping is unchanged
1911	+	*/
1912	+	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1913	+	if (key == null || value == null || remappingFunction == null)
1914	+	throw new NullPointerException();
1915	+	int h = spread(key.hashCode());
1916	+	V val = null;
1917	+	int delta = 0;
1918	+	int binCount = 0;
1919	+	for (Node<K,V>[] tab = table;;) {
1920	+	Node<K,V> f; int n, i, fh;
1921	+	if (tab == null || (n = tab.length) == 0)
1922	+	tab = initTable();
1923	+	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1924	+	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1925	+	delta = 1;
1926	+	val = value;
1927	+	break;
1928	+	}
1929	+	}
1930	+	else if ((fh = f.hash) == MOVED)
1931	+	tab = helpTransfer(tab, f);
1932	+	else {
1933	+	synchronized (f) {
1934	+	if (tabAt(tab, i) == f) {
1935	+	if (fh >= 0) {
1936	+	binCount = 1;
1937	+	for (Node<K,V> e = f, pred = null;; ++binCount) {
1938	+	K ek;
1939	+	if (e.hash == h &&
1940	+	((ek = e.key) == key ||
1941	+	(ek != null && key.equals(ek)))) {
1942	+	val = remappingFunction.apply(e.val, value);
1943	+	if (val != null)
1944	+	e.val = val;
1945	+	else {
1946	+	delta = -1;
1947	+	Node<K,V> en = e.next;
1948	+	if (pred != null)
1949	+	pred.next = en;
1950	+	else
1951	+	setTabAt(tab, i, en);
1952	+	}
1953	+	break;
1954	+	}
1955	+	pred = e;
1956	+	if ((e = e.next) == null) {
1957	+	delta = 1;
1958	+	val = value;
1959	+	pred.next =
1960	+	new Node<K,V>(h, key, val, null);
1961	+	break;
1962	+	}
1963	+	}
1964	+	}
1965	+	else if (f instanceof TreeBin) {
1966	+	binCount = 2;
1967	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
1968	+	TreeNode<K,V> r = t.root;
1969	+	TreeNode<K,V> p = (r == null) ? null :
1970	+	r.findTreeNode(h, key, null);
1971	+	val = (p == null) ? value :
1972	+	remappingFunction.apply(p.val, value);
1973	+	if (val != null) {
1974	+	if (p != null)
1975	+	p.val = val;
1976	+	else {
1977	+	delta = 1;
1978	+	t.putTreeVal(h, key, val);
1979	+	}
1980	+	}
1981	+	else if (p != null) {
1982	+	delta = -1;
1983	+	if (t.removeTreeNode(p))
1984	+	setTabAt(tab, i, untreeify(t.first));
1985	+	}
1986	+	}
1987	+	}
1988	+	}
1989	+	if (binCount != 0) {
1990	+	if (binCount >= TREEIFY_THRESHOLD)
1991	+	treeifyBin(tab, i);
1992	+	break;
1993	+	}
1994	+	}
1995	+	}
1996	+	if (delta != 0)
1997	+	addCount((long)delta, binCount);
1998	+	return val;
1999	+	}
2000	+
2001	+	// Hashtable legacy methods
2002	+
2003	+	/**
2004		* Legacy method testing if some key maps into the specified value
2005		* in this table.  This method is identical in functionality to
2006	<	* {@link #containsValue}, and exists solely to ensure
2006	>	* {@link #containsValue(Object)}, and exists solely to ensure
2007		* full compatibility with class {@link java.util.Hashtable},
2008		* which supported this method prior to introduction of the
2009		* Java Collections framework.
2010	<
2010	>	*
2011		* @param  value a value to search for
2012	<	* @return <tt>true</tt> if and only if some key maps to the
2013	<	*         <tt>value</tt> argument in this table as
2014	<	*         determined by the <tt>equals</tt> method;
2015	<	*         <tt>false</tt> otherwise
2012	>	* @return {@code true} if and only if some key maps to the
2013	>	*         {@code value} argument in this table as
2014	>	*         determined by the {@code equals} method;
2015	>	*         {@code false} otherwise
2016		* @throws NullPointerException if the specified value is null
2017		*/
2018	+	@Deprecated
2019		public boolean contains(Object value) {
2020		return containsValue(value);
2021		}
2022
2023		/**
2024	<	* Maps the specified key to the specified value in this table.
867	<	* Neither the key nor the value can be null.
868	<	*
869	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
870	<	* with a key that is equal to the original key.
2024	>	* Returns an enumeration of the keys in this table.
2025		*
2026	<	* @param key key with which the specified value is to be associated
2027	<	* @param value value to be associated with the specified key
874	<	* @return the previous value associated with <tt>key</tt>, or
875	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
876	<	* @throws NullPointerException if the specified key or value is null
2026	>	* @return an enumeration of the keys in this table
2027	>	* @see #keySet()
2028		*/
2029	<	public V put(K key, V value) {
2030	<	if (value == null)
2031	<	throw new NullPointerException();
2032	<	int hash = hash(key.hashCode());
882	<	return segmentFor(hash).put(key, hash, value, false);
2029	>	public Enumeration<K> keys() {
2030	>	Node<K,V>[] t;
2031	>	int f = (t = table) == null ? 0 : t.length;
2032	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2033		}
2034
2035		/**
2036	<	* {@inheritDoc}
2036	>	* Returns an enumeration of the values in this table.
2037		*
2038	<	* @return the previous value associated with the specified key,
2039	<	*         or <tt>null</tt> if there was no mapping for the key
890	<	* @throws NullPointerException if the specified key or value is null
2038	>	* @return an enumeration of the values in this table
2039	>	* @see #values()
2040		*/
2041	<	public V putIfAbsent(K key, V value) {
2042	<	if (value == null)
2043	<	throw new NullPointerException();
2044	<	int hash = hash(key.hashCode());
896	<	return segmentFor(hash).put(key, hash, value, true);
2041	>	public Enumeration<V> elements() {
2042	>	Node<K,V>[] t;
2043	>	int f = (t = table) == null ? 0 : t.length;
2044	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2045		}
2046
2047	+	// ConcurrentHashMap-only methods
2048	+
2049		/**
2050	<	* Copies all of the mappings from the specified map to this one.
2051	<	* These mappings replace any mappings that this map had for any of the
2052	<	* keys currently in the specified map.
2050	>	* Returns the number of mappings. This method should be used
2051	>	* instead of {@link #size} because a ConcurrentHashMap may
2052	>	* contain more mappings than can be represented as an int. The
2053	>	* value returned is an estimate; the actual count may differ if
2054	>	* there are concurrent insertions or removals.
2055		*
2056	<	* @param m mappings to be stored in this map
2056	>	* @return the number of mappings
2057	>	* @since 1.8
2058		*/
2059	<	public void putAll(Map<? extends K, ? extends V> m) {
2060	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2061	<	put(e.getKey(), e.getValue());
2059	>	public long mappingCount() {
2060	>	long n = sumCount();
2061	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2062		}
2063
2064		/**
2065	<	* Removes the key (and its corresponding value) from this map.
2066	<	* This method does nothing if the key is not in the map.
2065	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2066	>	* from the given type to {@code Boolean.TRUE}.
2067		*
2068	<	* @param  key the key that needs to be removed
2069	<	* @return the previous value associated with <tt>key</tt>, or
2070	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2071	<	* @throws NullPointerException if the specified key is null
2072	<	*/
2073	<	public V remove(Object key) {
2074	<	int hash = hash(key.hashCode());
922	<	return segmentFor(hash).remove(key, hash, null);
2068	>	* @param <K> the element type of the returned set
2069	>	* @return the new set
2070	>	* @since 1.8
2071	>	*/
2072	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2073	>	return new KeySetView<K,Boolean>
2074	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2075		}
2076
2077		/**
2078	<	* {@inheritDoc}
2078	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2079	>	* from the given type to {@code Boolean.TRUE}.
2080		*
2081	<	* @throws NullPointerException if the specified key is null
2081	>	* @param initialCapacity The implementation performs internal
2082	>	* sizing to accommodate this many elements.
2083	>	* @param <K> the element type of the returned set
2084	>	* @return the new set
2085	>	* @throws IllegalArgumentException if the initial capacity of
2086	>	* elements is negative
2087	>	* @since 1.8
2088		*/
2089	<	public boolean remove(Object key, Object value) {
2090	<	int hash = hash(key.hashCode());
2091	<	if (value == null)
933	<	return false;
934	<	return segmentFor(hash).remove(key, hash, value) != null;
2089	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2090	>	return new KeySetView<K,Boolean>
2091	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2092		}
2093
2094		/**
2095	<	* {@inheritDoc}
2095	>	* Returns a {@link Set} view of the keys in this map, using the
2096	>	* given common mapped value for any additions (i.e., {@link
2097	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2098	>	* This is of course only appropriate if it is acceptable to use
2099	>	* the same value for all additions from this view.
2100		*
2101	<	* @throws NullPointerException if any of the arguments are null
2101	>	* @param mappedValue the mapped value to use for any additions
2102	>	* @return the set view
2103	>	* @throws NullPointerException if the mappedValue is null
2104		*/
2105	<	public boolean replace(K key, V oldValue, V newValue) {
2106	<	if (oldValue == null || newValue == null)
2105	>	public KeySetView<K,V> keySet(V mappedValue) {
2106	>	if (mappedValue == null)
2107		throw new NullPointerException();
2108	<	int hash = hash(key.hashCode());
946	<	return segmentFor(hash).replace(key, hash, oldValue, newValue);
2108	>	return new KeySetView<K,V>(this, mappedValue);
2109		}
2110
2111	+	/* ---------------- Special Nodes -------------- */
2112	+
2113		/**
2114	<	* {@inheritDoc}
951	<	*
952	<	* @return the previous value associated with the specified key,
953	<	*         or <tt>null</tt> if there was no mapping for the key
954	<	* @throws NullPointerException if the specified key or value is null
2114	>	* A node inserted at head of bins during transfer operations.
2115		*/
2116	<	public V replace(K key, V value) {
2117	<	if (value == null)
2118	<	throw new NullPointerException();
2119	<	int hash = hash(key.hashCode());
2120	<	return segmentFor(hash).replace(key, hash, value);
2116	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2117	>	final Node<K,V>[] nextTable;
2118	>	ForwardingNode(Node<K,V>[] tab) {
2119	>	super(MOVED, null, null, null);
2120	>	this.nextTable = tab;
2121	>	}
2122	>
2123	>	Node<K,V> find(int h, Object k) {
2124	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2125	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2126	>	Node<K,V> e; int n;
2127	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2128	>	(e = tabAt(tab, (n - 1) & h)) == null)
2129	>	return null;
2130	>	for (;;) {
2131	>	int eh; K ek;
2132	>	if ((eh = e.hash) == h &&
2133	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2134	>	return e;
2135	>	if (eh < 0) {
2136	>	if (e instanceof ForwardingNode) {
2137	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2138	>	continue outer;
2139	>	}
2140	>	else
2141	>	return e.find(h, k);
2142	>	}
2143	>	if ((e = e.next) == null)
2144	>	return null;
2145	>	}
2146	>	}
2147	>	}
2148		}
2149
2150		/**
2151	<	* Removes all of the mappings from this map.
2151	>	* A place-holder node used in computeIfAbsent and compute
2152		*/
2153	<	public void clear() {
2154	<	for (int i = 0; i < segments.length; ++i)
2155	<	segments[i].clear();
2153	>	static final class ReservationNode<K,V> extends Node<K,V> {
2154	>	ReservationNode() {
2155	>	super(RESERVED, null, null, null);
2156	>	}
2157	>
2158	>	Node<K,V> find(int h, Object k) {
2159	>	return null;
2160	>	}
2161		}
2162
2163	+	/* ---------------- Table Initialization and Resizing -------------- */
2164	+
2165		/**
2166	<	* Returns a {@link Set} view of the keys contained in this map.
2167	<	* The set is backed by the map, so changes to the map are
2168	<	* reflected in the set, and vice-versa.  The set supports element
2169	<	* removal, which removes the corresponding mapping from this map,
2170	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2171	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2172	<	* operations.  It does not support the <tt>add</tt> or
2173	<	* <tt>addAll</tt> operations.
2174	<	*
2175	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2176	<	* that will never throw {@link ConcurrentModificationException},
2177	<	* and guarantees to traverse elements as they existed upon
2178	<	* construction of the iterator, and may (but is not guaranteed to)
2179	<	* reflect any modifications subsequent to construction.
2180	<	*/
2181	<	public Set<K> keySet() {
2182	<	Set<K> ks = keySet;
2183	<	return (ks != null) ? ks : (keySet = new KeySet());
2166	>	* Initializes table, using the size recorded in sizeCtl.
2167	>	*/
2168	>	private final Node<K,V>[] initTable() {
2169	>	Node<K,V>[] tab; int sc;
2170	>	while ((tab = table) == null || tab.length == 0) {
2171	>	if ((sc = sizeCtl) < 0)
2172	>	Thread.yield(); // lost initialization race; just spin
2173	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2174	>	try {
2175	>	if ((tab = table) == null || tab.length == 0) {
2176	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2177	>	@SuppressWarnings("unchecked")
2178	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2179	>	table = tab = nt;
2180	>	sc = n - (n >>> 2);
2181	>	}
2182	>	} finally {
2183	>	sizeCtl = sc;
2184	>	}
2185	>	break;
2186	>	}
2187	>	}
2188	>	return tab;
2189		}
2190
2191		/**
2192	<	* Returns a {@link Collection} view of the values contained in this map.
2193	<	* The collection is backed by the map, so changes to the map are
2194	<	* reflected in the collection, and vice-versa.  The collection
2195	<	* supports element removal, which removes the corresponding
2196	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
2197	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
2198	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
2199	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
1001	<	*
1002	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1003	<	* that will never throw {@link ConcurrentModificationException},
1004	<	* and guarantees to traverse elements as they existed upon
1005	<	* construction of the iterator, and may (but is not guaranteed to)
1006	<	* reflect any modifications subsequent to construction.
2192	>	* Adds to count, and if table is too small and not already
2193	>	* resizing, initiates transfer. If already resizing, helps
2194	>	* perform transfer if work is available.  Rechecks occupancy
2195	>	* after a transfer to see if another resize is already needed
2196	>	* because resizings are lagging additions.
2197	>	*
2198	>	* @param x the count to add
2199	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2200		*/
2201	<	public Collection<V> values() {
2202	<	Collection<V> vs = values;
2203	<	return (vs != null) ? vs : (values = new Values());
2201	>	private final void addCount(long x, int check) {
2202	>	CounterCell[] as; long b, s;
2203	>	if ((as = counterCells) != null ||
2204	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2205	>	CounterCell a; long v; int m;
2206	>	boolean uncontended = true;
2207	>	if (as == null || (m = as.length - 1) < 0 ||
2208	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2209	>	!(uncontended =
2210	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2211	>	fullAddCount(x, uncontended);
2212	>	return;
2213	>	}
2214	>	if (check <= 1)
2215	>	return;
2216	>	s = sumCount();
2217	>	}
2218	>	if (check >= 0) {
2219	>	Node<K,V>[] tab, nt; int sc;
2220	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2221	>	tab.length < MAXIMUM_CAPACITY) {
2222	>	if (sc < 0) {
2223	>	if (sc == -1 || transferIndex <= 0 ||
2224	>	(nt = nextTable) == null)
2225	>	break;
2226	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
2227	>	transfer(tab, nt);
2228	>	}
2229	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
2230	>	transfer(tab, null);
2231	>	s = sumCount();
2232	>	}
2233	>	}
2234		}
2235
2236		/**
2237	<	* Returns a {@link Set} view of the mappings contained in this map.
1015	<	* The set is backed by the map, so changes to the map are
1016	<	* reflected in the set, and vice-versa.  The set supports element
1017	<	* removal, which removes the corresponding mapping from the map,
1018	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1019	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1020	<	* operations.  It does not support the <tt>add</tt> or
1021	<	* <tt>addAll</tt> operations.
1022	<	*
1023	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1024	<	* that will never throw {@link ConcurrentModificationException},
1025	<	* and guarantees to traverse elements as they existed upon
1026	<	* construction of the iterator, and may (but is not guaranteed to)
1027	<	* reflect any modifications subsequent to construction.
2237	>	* Helps transfer if a resize is in progress.
2238		*/
2239	<	public Set<Map.Entry<K,V>> entrySet() {
2240	<	Set<Map.Entry<K,V>> es = entrySet;
2241	<	return (es != null) ? es : (entrySet = new EntrySet());
2239	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2240	>	Node<K,V>[] nextTab; int sc;
2241	>	if ((f instanceof ForwardingNode) &&
2242	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2243	>	while (transferIndex > 0 && nextTab == nextTable &&
2244	>	(sc = sizeCtl) < -1) {
2245	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) {
2246	>	transfer(tab, nextTab);
2247	>	break;
2248	>	}
2249	>	}
2250	>	return nextTab;
2251	>	}
2252	>	return table;
2253		}
2254
2255		/**
2256	<	* Returns an enumeration of the keys in this table.
2256	>	* Tries to presize table to accommodate the given number of elements.
2257		*
2258	<	* @return an enumeration of the keys in this table
1038	<	* @see #keySet
2258	>	* @param size number of elements (doesn't need to be perfectly accurate)
2259		*/
2260	<	public Enumeration<K> keys() {
2261	<	return new KeyIterator();
2260	>	private final void tryPresize(int size) {
2261	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2262	>	tableSizeFor(size + (size >>> 1) + 1);
2263	>	int sc;
2264	>	while ((sc = sizeCtl) >= 0) {
2265	>	Node<K,V>[] tab = table; int n;
2266	>	if (tab == null || (n = tab.length) == 0) {
2267	>	n = (sc > c) ? sc : c;
2268	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2269	>	try {
2270	>	if (table == tab) {
2271	>	@SuppressWarnings("unchecked")
2272	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2273	>	table = nt;
2274	>	sc = n - (n >>> 2);
2275	>	}
2276	>	} finally {
2277	>	sizeCtl = sc;
2278	>	}
2279	>	}
2280	>	}
2281	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2282	>	break;
2283	>	else if (tab == table &&
2284	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
2285	>	transfer(tab, null);
2286	>	}
2287		}
2288
2289		/**
2290	<	* Returns an enumeration of the values in this table.
2291	<	*
1047	<	* @return an enumeration of the values in this table
1048	<	* @see #values
2290	>	* Moves and/or copies the nodes in each bin to new table. See
2291	>	* above for explanation.
2292		*/
2293	<	public Enumeration<V> elements() {
2294	<	return new ValueIterator();
2293	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2294	>	int n = tab.length, stride;
2295	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2296	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2297	>	if (nextTab == null) {            // initiating
2298	>	try {
2299	>	@SuppressWarnings("unchecked")
2300	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2301	>	nextTab = nt;
2302	>	} catch (Throwable ex) {      // try to cope with OOME
2303	>	sizeCtl = Integer.MAX_VALUE;
2304	>	return;
2305	>	}
2306	>	nextTable = nextTab;
2307	>	transferIndex = n;
2308	>	}
2309	>	int nextn = nextTab.length;
2310	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2311	>	boolean advance = true;
2312	>	boolean finishing = false; // to ensure sweep before committing nextTab
2313	>	for (int i = 0, bound = 0;;) {
2314	>	Node<K,V> f; int fh;
2315	>	while (advance) {
2316	>	int nextIndex, nextBound;
2317	>	if (--i >= bound || finishing)
2318	>	advance = false;
2319	>	else if ((nextIndex = transferIndex) <= 0) {
2320	>	i = -1;
2321	>	advance = false;
2322	>	}
2323	>	else if (U.compareAndSwapInt
2324	>	(this, TRANSFERINDEX, nextIndex,
2325	>	nextBound = (nextIndex > stride ?
2326	>	nextIndex - stride : 0))) {
2327	>	bound = nextBound;
2328	>	i = nextIndex - 1;
2329	>	advance = false;
2330	>	}
2331	>	}
2332	>	if (i < 0 || i >= n || i + n >= nextn) {
2333	>	int sc;
2334	>	if (finishing) {
2335	>	nextTable = null;
2336	>	table = nextTab;
2337	>	sizeCtl = (n << 1) - (n >>> 1);
2338	>	return;
2339	>	}
2340	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
2341	>	if (sc != -1)
2342	>	return;
2343	>	finishing = advance = true;
2344	>	i = n; // recheck before commit
2345	>	}
2346	>	}
2347	>	else if ((f = tabAt(tab, i)) == null)
2348	>	advance = casTabAt(tab, i, null, fwd);
2349	>	else if ((fh = f.hash) == MOVED)
2350	>	advance = true; // already processed
2351	>	else {
2352	>	synchronized (f) {
2353	>	if (tabAt(tab, i) == f) {
2354	>	Node<K,V> ln, hn;
2355	>	if (fh >= 0) {
2356	>	int runBit = fh & n;
2357	>	Node<K,V> lastRun = f;
2358	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2359	>	int b = p.hash & n;
2360	>	if (b != runBit) {
2361	>	runBit = b;
2362	>	lastRun = p;
2363	>	}
2364	>	}
2365	>	if (runBit == 0) {
2366	>	ln = lastRun;
2367	>	hn = null;
2368	>	}
2369	>	else {
2370	>	hn = lastRun;
2371	>	ln = null;
2372	>	}
2373	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2374	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2375	>	if ((ph & n) == 0)
2376	>	ln = new Node<K,V>(ph, pk, pv, ln);
2377	>	else
2378	>	hn = new Node<K,V>(ph, pk, pv, hn);
2379	>	}
2380	>	setTabAt(nextTab, i, ln);
2381	>	setTabAt(nextTab, i + n, hn);
2382	>	setTabAt(tab, i, fwd);
2383	>	advance = true;
2384	>	}
2385	>	else if (f instanceof TreeBin) {
2386	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2387	>	TreeNode<K,V> lo = null, loTail = null;
2388	>	TreeNode<K,V> hi = null, hiTail = null;
2389	>	int lc = 0, hc = 0;
2390	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2391	>	int h = e.hash;
2392	>	TreeNode<K,V> p = new TreeNode<K,V>
2393	>	(h, e.key, e.val, null, null);
2394	>	if ((h & n) == 0) {
2395	>	if ((p.prev = loTail) == null)
2396	>	lo = p;
2397	>	else
2398	>	loTail.next = p;
2399	>	loTail = p;
2400	>	++lc;
2401	>	}
2402	>	else {
2403	>	if ((p.prev = hiTail) == null)
2404	>	hi = p;
2405	>	else
2406	>	hiTail.next = p;
2407	>	hiTail = p;
2408	>	++hc;
2409	>	}
2410	>	}
2411	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2412	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2413	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2414	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2415	>	setTabAt(nextTab, i, ln);
2416	>	setTabAt(nextTab, i + n, hn);
2417	>	setTabAt(tab, i, fwd);
2418	>	advance = true;
2419	>	}
2420	>	}
2421	>	}
2422	>	}
2423	>	}
2424		}
2425
2426	<	/* ---------------- Iterator Support -------------- */
2426	>	/* ---------------- Counter support -------------- */
2427
2428	<	abstract class HashIterator {
2429	<	int nextSegmentIndex;
2430	<	int nextTableIndex;
2431	<	HashEntry<K,V>[] currentTable;
2432	<	HashEntry<K, V> nextEntry;
2433	<	HashEntry<K, V> lastReturned;
2428	>	/**
2429	>	* A padded cell for distributing counts.  Adapted from LongAdder
2430	>	* and Striped64.  See their internal docs for explanation.
2431	>	*/
2432	>	@sun.misc.Contended static final class CounterCell {
2433	>	volatile long value;
2434	>	CounterCell(long x) { value = x; }
2435	>	}
2436
2437	<	HashIterator() {
2438	<	nextSegmentIndex = segments.length - 1;
2439	<	nextTableIndex = -1;
2440	<	advance();
2437	>	final long sumCount() {
2438	>	CounterCell[] as = counterCells; CounterCell a;
2439	>	long sum = baseCount;
2440	>	if (as != null) {
2441	>	for (int i = 0; i < as.length; ++i) {
2442	>	if ((a = as[i]) != null)
2443	>	sum += a.value;
2444	>	}
2445		}
2446	+	return sum;
2447	+	}
2448
2449	<	public boolean hasMoreElements() { return hasNext(); }
2449	>	// See LongAdder version for explanation
2450	>	private final void fullAddCount(long x, boolean wasUncontended) {
2451	>	int h;
2452	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2453	>	ThreadLocalRandom.localInit();      // force initialization
2454	>	h = ThreadLocalRandom.getProbe();
2455	>	wasUncontended = true;
2456	>	}
2457	>	boolean collide = false;                // True if last slot nonempty
2458	>	for (;;) {
2459	>	CounterCell[] as; CounterCell a; int n; long v;
2460	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2461	>	if ((a = as[(n - 1) & h]) == null) {
2462	>	if (cellsBusy == 0) {            // Try to attach new Cell
2463	>	CounterCell r = new CounterCell(x); // Optimistic create
2464	>	if (cellsBusy == 0 &&
2465	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2466	>	boolean created = false;
2467	>	try {               // Recheck under lock
2468	>	CounterCell[] rs; int m, j;
2469	>	if ((rs = counterCells) != null &&
2470	>	(m = rs.length) > 0 &&
2471	>	rs[j = (m - 1) & h] == null) {
2472	>	rs[j] = r;
2473	>	created = true;
2474	>	}
2475	>	} finally {
2476	>	cellsBusy = 0;
2477	>	}
2478	>	if (created)
2479	>	break;
2480	>	continue;           // Slot is now non-empty
2481	>	}
2482	>	}
2483	>	collide = false;
2484	>	}
2485	>	else if (!wasUncontended)       // CAS already known to fail
2486	>	wasUncontended = true;      // Continue after rehash
2487	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2488	>	break;
2489	>	else if (counterCells != as || n >= NCPU)
2490	>	collide = false;            // At max size or stale
2491	>	else if (!collide)
2492	>	collide = true;
2493	>	else if (cellsBusy == 0 &&
2494	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2495	>	try {
2496	>	if (counterCells == as) {// Expand table unless stale
2497	>	CounterCell[] rs = new CounterCell[n << 1];
2498	>	for (int i = 0; i < n; ++i)
2499	>	rs[i] = as[i];
2500	>	counterCells = rs;
2501	>	}
2502	>	} finally {
2503	>	cellsBusy = 0;
2504	>	}
2505	>	collide = false;
2506	>	continue;                   // Retry with expanded table
2507	>	}
2508	>	h = ThreadLocalRandom.advanceProbe(h);
2509	>	}
2510	>	else if (cellsBusy == 0 && counterCells == as &&
2511	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2512	>	boolean init = false;
2513	>	try {                           // Initialize table
2514	>	if (counterCells == as) {
2515	>	CounterCell[] rs = new CounterCell[2];
2516	>	rs[h & 1] = new CounterCell(x);
2517	>	counterCells = rs;
2518	>	init = true;
2519	>	}
2520	>	} finally {
2521	>	cellsBusy = 0;
2522	>	}
2523	>	if (init)
2524	>	break;
2525	>	}
2526	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2527	>	break;                          // Fall back on using base
2528	>	}
2529	>	}
2530
2531	<	final void advance() {
1072	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
1073	<	return;
2531	>	/* ---------------- Conversion from/to TreeBins -------------- */
2532
2533	<	while (nextTableIndex >= 0) {
2534	<	if ( (nextEntry = currentTable[nextTableIndex--]) != null)
2535	<	return;
2533	>	/**
2534	>	* Replaces all linked nodes in bin at given index unless table is
2535	>	* too small, in which case resizes instead.
2536	>	*/
2537	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2538	>	Node<K,V> b; int n, sc;
2539	>	if (tab != null) {
2540	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY) {
2541	>	if (tab == table && (sc = sizeCtl) >= 0 &&
2542	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
2543	>	transfer(tab, null);
2544	>	}
2545	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2546	>	synchronized (b) {
2547	>	if (tabAt(tab, index) == b) {
2548	>	TreeNode<K,V> hd = null, tl = null;
2549	>	for (Node<K,V> e = b; e != null; e = e.next) {
2550	>	TreeNode<K,V> p =
2551	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2552	>	null, null);
2553	>	if ((p.prev = tl) == null)
2554	>	hd = p;
2555	>	else
2556	>	tl.next = p;
2557	>	tl = p;
2558	>	}
2559	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2560	>	}
2561	>	}
2562	>	}
2563	>	}
2564	>	}
2565	>
2566	>	/**
2567	>	* Returns a list on non-TreeNodes replacing those in given list.
2568	>	*/
2569	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2570	>	Node<K,V> hd = null, tl = null;
2571	>	for (Node<K,V> q = b; q != null; q = q.next) {
2572	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2573	>	if (tl == null)
2574	>	hd = p;
2575	>	else
2576	>	tl.next = p;
2577	>	tl = p;
2578	>	}
2579	>	return hd;
2580	>	}
2581	>
2582	>	/* ---------------- TreeNodes -------------- */
2583	>
2584	>	/**
2585	>	* Nodes for use in TreeBins
2586	>	*/
2587	>	static final class TreeNode<K,V> extends Node<K,V> {
2588	>	TreeNode<K,V> parent;  // red-black tree links
2589	>	TreeNode<K,V> left;
2590	>	TreeNode<K,V> right;
2591	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2592	>	boolean red;
2593	>
2594	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2595	>	TreeNode<K,V> parent) {
2596	>	super(hash, key, val, next);
2597	>	this.parent = parent;
2598	>	}
2599	>
2600	>	Node<K,V> find(int h, Object k) {
2601	>	return findTreeNode(h, k, null);
2602	>	}
2603	>
2604	>	/**
2605	>	* Returns the TreeNode (or null if not found) for the given key
2606	>	* starting at given root.
2607	>	*/
2608	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2609	>	if (k != null) {
2610	>	TreeNode<K,V> p = this;
2611	>	do  {
2612	>	int ph, dir; K pk; TreeNode<K,V> q;
2613	>	TreeNode<K,V> pl = p.left, pr = p.right;
2614	>	if ((ph = p.hash) > h)
2615	>	p = pl;
2616	>	else if (ph < h)
2617	>	p = pr;
2618	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2619	>	return p;
2620	>	else if (pl == null)
2621	>	p = pr;
2622	>	else if (pr == null)
2623	>	p = pl;
2624	>	else if ((kc != null ||
2625	>	(kc = comparableClassFor(k)) != null) &&
2626	>	(dir = compareComparables(kc, k, pk)) != 0)
2627	>	p = (dir < 0) ? pl : pr;
2628	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2629	>	return q;
2630	>	else
2631	>	p = pl;
2632	>	} while (p != null);
2633		}
2634	+	return null;
2635	+	}
2636	+	}
2637	+
2638	+	/* ---------------- TreeBins -------------- */
2639
2640	<	while (nextSegmentIndex >= 0) {
2641	<	Segment<K,V> seg = segments[nextSegmentIndex--];
2642	<	if (seg.count != 0) {
2643	<	currentTable = seg.table;
2644	<	for (int j = currentTable.length - 1; j >= 0; --j) {
2645	<	if ( (nextEntry = currentTable[j]) != null) {
2646	<	nextTableIndex = j - 1;
2647	<	return;
2640	>	/**
2641	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2642	>	* keys or values, but instead point to list of TreeNodes and
2643	>	* their root. They also maintain a parasitic read-write lock
2644	>	* forcing writers (who hold bin lock) to wait for readers (who do
2645	>	* not) to complete before tree restructuring operations.
2646	>	*/
2647	>	static final class TreeBin<K,V> extends Node<K,V> {
2648	>	TreeNode<K,V> root;
2649	>	volatile TreeNode<K,V> first;
2650	>	volatile Thread waiter;
2651	>	volatile int lockState;
2652	>	// values for lockState
2653	>	static final int WRITER = 1; // set while holding write lock
2654	>	static final int WAITER = 2; // set when waiting for write lock
2655	>	static final int READER = 4; // increment value for setting read lock
2656	>
2657	>	/**
2658	>	* Tie-breaking utility for ordering insertions when equal
2659	>	* hashCodes and non-comparable. We don't require a total
2660	>	* order, just a consistent insertion rule to maintain
2661	>	* equivalence across rebalancings. Tie-breaking further than
2662	>	* necessary simplifies testing a bit.
2663	>	*/
2664	>	static int tieBreakOrder(Object a, Object b) {
2665	>	int d;
2666	>	if (a == null || b == null ||
2667	>	(d = a.getClass().getName().
2668	>	compareTo(b.getClass().getName())) == 0)
2669	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2670	>	-1 : 1);
2671	>	return d;
2672	>	}
2673	>
2674	>	/**
2675	>	* Creates bin with initial set of nodes headed by b.
2676	>	*/
2677	>	TreeBin(TreeNode<K,V> b) {
2678	>	super(TREEBIN, null, null, null);
2679	>	this.first = b;
2680	>	TreeNode<K,V> r = null;
2681	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2682	>	next = (TreeNode<K,V>)x.next;
2683	>	x.left = x.right = null;
2684	>	if (r == null) {
2685	>	x.parent = null;
2686	>	x.red = false;
2687	>	r = x;
2688	>	}
2689	>	else {
2690	>	K k = x.key;
2691	>	int h = x.hash;
2692	>	Class<?> kc = null;
2693	>	for (TreeNode<K,V> p = r;;) {
2694	>	int dir, ph;
2695	>	K pk = p.key;
2696	>	if ((ph = p.hash) > h)
2697	>	dir = -1;
2698	>	else if (ph < h)
2699	>	dir = 1;
2700	>	else if ((kc == null &&
2701	>	(kc = comparableClassFor(k)) == null) ||
2702	>	(dir = compareComparables(kc, k, pk)) == 0)
2703	>	dir = tieBreakOrder(k, pk);
2704	>	TreeNode<K,V> xp = p;
2705	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2706	>	x.parent = xp;
2707	>	if (dir <= 0)
2708	>	xp.left = x;
2709	>	else
2710	>	xp.right = x;
2711	>	r = balanceInsertion(r, x);
2712	>	break;
2713		}
2714		}
2715		}
2716		}
2717	+	this.root = r;
2718	+	assert checkInvariants(root);
2719		}
2720
2721	<	public boolean hasNext() { return nextEntry != null; }
2721	>	/**
2722	>	* Acquires write lock for tree restructuring.
2723	>	*/
2724	>	private final void lockRoot() {
2725	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2726	>	contendedLock(); // offload to separate method
2727	>	}
2728
2729	<	HashEntry<K,V> nextEntry() {
2730	<	if (nextEntry == null)
2731	<	throw new NoSuchElementException();
2732	<	lastReturned = nextEntry;
2729	>	/**
2730	>	* Releases write lock for tree restructuring.
2731	>	*/
2732	>	private final void unlockRoot() {
2733	>	lockState = 0;
2734	>	}
2735	>
2736	>	/**
2737	>	* Possibly blocks awaiting root lock.
2738	>	*/
2739	>	private final void contendedLock() {
2740	>	boolean waiting = false;
2741	>	for (int s;;) {
2742	>	if (((s = lockState) & WRITER) == 0) {
2743	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2744	>	if (waiting)
2745	>	waiter = null;
2746	>	return;
2747	>	}
2748	>	}
2749	>	else if ((s & WAITER) == 0) {
2750	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2751	>	waiting = true;
2752	>	waiter = Thread.currentThread();
2753	>	}
2754	>	}
2755	>	else if (waiting)
2756	>	LockSupport.park(this);
2757	>	}
2758	>	}
2759	>
2760	>	/**
2761	>	* Returns matching node or null if none. Tries to search
2762	>	* using tree comparisons from root, but continues linear
2763	>	* search when lock not available.
2764	>	*/
2765	>	final Node<K,V> find(int h, Object k) {
2766	>	if (k != null) {
2767	>	for (Node<K,V> e = first; e != null; e = e.next) {
2768	>	int s; K ek;
2769	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2770	>	if (e.hash == h &&
2771	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2772	>	return e;
2773	>	}
2774	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2775	>	s + READER)) {
2776	>	TreeNode<K,V> r, p;
2777	>	try {
2778	>	p = ((r = root) == null ? null :
2779	>	r.findTreeNode(h, k, null));
2780	>	} finally {
2781	>	Thread w;
2782	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2783	>	(READER|WAITER) && (w = waiter) != null)
2784	>	LockSupport.unpark(w);
2785	>	}
2786	>	return p;
2787	>	}
2788	>	}
2789	>	}
2790	>	return null;
2791	>	}
2792	>
2793	>	/**
2794	>	* Finds or adds a node.
2795	>	* @return null if added
2796	>	*/
2797	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2798	>	Class<?> kc = null;
2799	>	boolean searched = false;
2800	>	for (TreeNode<K,V> p = root;;) {
2801	>	int dir, ph; K pk;
2802	>	if (p == null) {
2803	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2804	>	break;
2805	>	}
2806	>	else if ((ph = p.hash) > h)
2807	>	dir = -1;
2808	>	else if (ph < h)
2809	>	dir = 1;
2810	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2811	>	return p;
2812	>	else if ((kc == null &&
2813	>	(kc = comparableClassFor(k)) == null) ||
2814	>	(dir = compareComparables(kc, k, pk)) == 0) {
2815	>	if (!searched) {
2816	>	TreeNode<K,V> q, ch;
2817	>	searched = true;
2818	>	if (((ch = p.left) != null &&
2819	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2820	>	((ch = p.right) != null &&
2821	>	(q = ch.findTreeNode(h, k, kc)) != null))
2822	>	return q;
2823	>	}
2824	>	dir = tieBreakOrder(k, pk);
2825	>	}
2826	>
2827	>	TreeNode<K,V> xp = p;
2828	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2829	>	TreeNode<K,V> x, f = first;
2830	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2831	>	if (f != null)
2832	>	f.prev = x;
2833	>	if (dir <= 0)
2834	>	xp.left = x;
2835	>	else
2836	>	xp.right = x;
2837	>	if (!xp.red)
2838	>	x.red = true;
2839	>	else {
2840	>	lockRoot();
2841	>	try {
2842	>	root = balanceInsertion(root, x);
2843	>	} finally {
2844	>	unlockRoot();
2845	>	}
2846	>	}
2847	>	break;
2848	>	}
2849	>	}
2850	>	assert checkInvariants(root);
2851	>	return null;
2852	>	}
2853	>
2854	>	/**
2855	>	* Removes the given node, that must be present before this
2856	>	* call.  This is messier than typical red-black deletion code
2857	>	* because we cannot swap the contents of an interior node
2858	>	* with a leaf successor that is pinned by "next" pointers
2859	>	* that are accessible independently of lock. So instead we
2860	>	* swap the tree linkages.
2861	>	*
2862	>	* @return true if now too small, so should be untreeified
2863	>	*/
2864	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2865	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2866	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2867	>	TreeNode<K,V> r, rl;
2868	>	if (pred == null)
2869	>	first = next;
2870	>	else
2871	>	pred.next = next;
2872	>	if (next != null)
2873	>	next.prev = pred;
2874	>	if (first == null) {
2875	>	root = null;
2876	>	return true;
2877	>	}
2878	>	if ((r = root) == null || r.right == null || // too small
2879	>	(rl = r.left) == null || rl.left == null)
2880	>	return true;
2881	>	lockRoot();
2882	>	try {
2883	>	TreeNode<K,V> replacement;
2884	>	TreeNode<K,V> pl = p.left;
2885	>	TreeNode<K,V> pr = p.right;
2886	>	if (pl != null && pr != null) {
2887	>	TreeNode<K,V> s = pr, sl;
2888	>	while ((sl = s.left) != null) // find successor
2889	>	s = sl;
2890	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2891	>	TreeNode<K,V> sr = s.right;
2892	>	TreeNode<K,V> pp = p.parent;
2893	>	if (s == pr) { // p was s's direct parent
2894	>	p.parent = s;
2895	>	s.right = p;
2896	>	}
2897	>	else {
2898	>	TreeNode<K,V> sp = s.parent;
2899	>	if ((p.parent = sp) != null) {
2900	>	if (s == sp.left)
2901	>	sp.left = p;
2902	>	else
2903	>	sp.right = p;
2904	>	}
2905	>	if ((s.right = pr) != null)
2906	>	pr.parent = s;
2907	>	}
2908	>	p.left = null;
2909	>	if ((p.right = sr) != null)
2910	>	sr.parent = p;
2911	>	if ((s.left = pl) != null)
2912	>	pl.parent = s;
2913	>	if ((s.parent = pp) == null)
2914	>	r = s;
2915	>	else if (p == pp.left)
2916	>	pp.left = s;
2917	>	else
2918	>	pp.right = s;
2919	>	if (sr != null)
2920	>	replacement = sr;
2921	>	else
2922	>	replacement = p;
2923	>	}
2924	>	else if (pl != null)
2925	>	replacement = pl;
2926	>	else if (pr != null)
2927	>	replacement = pr;
2928	>	else
2929	>	replacement = p;
2930	>	if (replacement != p) {
2931	>	TreeNode<K,V> pp = replacement.parent = p.parent;
2932	>	if (pp == null)
2933	>	r = replacement;
2934	>	else if (p == pp.left)
2935	>	pp.left = replacement;
2936	>	else
2937	>	pp.right = replacement;
2938	>	p.left = p.right = p.parent = null;
2939	>	}
2940	>
2941	>	root = (p.red) ? r : balanceDeletion(r, replacement);
2942	>
2943	>	if (p == replacement) {  // detach pointers
2944	>	TreeNode<K,V> pp;
2945	>	if ((pp = p.parent) != null) {
2946	>	if (p == pp.left)
2947	>	pp.left = null;
2948	>	else if (p == pp.right)
2949	>	pp.right = null;
2950	>	p.parent = null;
2951	>	}
2952	>	}
2953	>	} finally {
2954	>	unlockRoot();
2955	>	}
2956	>	assert checkInvariants(root);
2957	>	return false;
2958	>	}
2959	>
2960	>	/* ------------------------------------------------------------ */
2961	>	// Red-black tree methods, all adapted from CLR
2962	>
2963	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2964	>	TreeNode<K,V> p) {
2965	>	TreeNode<K,V> r, pp, rl;
2966	>	if (p != null && (r = p.right) != null) {
2967	>	if ((rl = p.right = r.left) != null)
2968	>	rl.parent = p;
2969	>	if ((pp = r.parent = p.parent) == null)
2970	>	(root = r).red = false;
2971	>	else if (pp.left == p)
2972	>	pp.left = r;
2973	>	else
2974	>	pp.right = r;
2975	>	r.left = p;
2976	>	p.parent = r;
2977	>	}
2978	>	return root;
2979	>	}
2980	>
2981	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2982	>	TreeNode<K,V> p) {
2983	>	TreeNode<K,V> l, pp, lr;
2984	>	if (p != null && (l = p.left) != null) {
2985	>	if ((lr = p.left = l.right) != null)
2986	>	lr.parent = p;
2987	>	if ((pp = l.parent = p.parent) == null)
2988	>	(root = l).red = false;
2989	>	else if (pp.right == p)
2990	>	pp.right = l;
2991	>	else
2992	>	pp.left = l;
2993	>	l.right = p;
2994	>	p.parent = l;
2995	>	}
2996	>	return root;
2997	>	}
2998	>
2999	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3000	>	TreeNode<K,V> x) {
3001	>	x.red = true;
3002	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3003	>	if ((xp = x.parent) == null) {
3004	>	x.red = false;
3005	>	return x;
3006	>	}
3007	>	else if (!xp.red || (xpp = xp.parent) == null)
3008	>	return root;
3009	>	if (xp == (xppl = xpp.left)) {
3010	>	if ((xppr = xpp.right) != null && xppr.red) {
3011	>	xppr.red = false;
3012	>	xp.red = false;
3013	>	xpp.red = true;
3014	>	x = xpp;
3015	>	}
3016	>	else {
3017	>	if (x == xp.right) {
3018	>	root = rotateLeft(root, x = xp);
3019	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3020	>	}
3021	>	if (xp != null) {
3022	>	xp.red = false;
3023	>	if (xpp != null) {
3024	>	xpp.red = true;
3025	>	root = rotateRight(root, xpp);
3026	>	}
3027	>	}
3028	>	}
3029	>	}
3030	>	else {
3031	>	if (xppl != null && xppl.red) {
3032	>	xppl.red = false;
3033	>	xp.red = false;
3034	>	xpp.red = true;
3035	>	x = xpp;
3036	>	}
3037	>	else {
3038	>	if (x == xp.left) {
3039	>	root = rotateRight(root, x = xp);
3040	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3041	>	}
3042	>	if (xp != null) {
3043	>	xp.red = false;
3044	>	if (xpp != null) {
3045	>	xpp.red = true;
3046	>	root = rotateLeft(root, xpp);
3047	>	}
3048	>	}
3049	>	}
3050	>	}
3051	>	}
3052	>	}
3053	>
3054	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3055	>	TreeNode<K,V> x) {
3056	>	for (TreeNode<K,V> xp, xpl, xpr;;)  {
3057	>	if (x == null || x == root)
3058	>	return root;
3059	>	else if ((xp = x.parent) == null) {
3060	>	x.red = false;
3061	>	return x;
3062	>	}
3063	>	else if (x.red) {
3064	>	x.red = false;
3065	>	return root;
3066	>	}
3067	>	else if ((xpl = xp.left) == x) {
3068	>	if ((xpr = xp.right) != null && xpr.red) {
3069	>	xpr.red = false;
3070	>	xp.red = true;
3071	>	root = rotateLeft(root, xp);
3072	>	xpr = (xp = x.parent) == null ? null : xp.right;
3073	>	}
3074	>	if (xpr == null)
3075	>	x = xp;
3076	>	else {
3077	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3078	>	if ((sr == null || !sr.red) &&
3079	>	(sl == null || !sl.red)) {
3080	>	xpr.red = true;
3081	>	x = xp;
3082	>	}
3083	>	else {
3084	>	if (sr == null || !sr.red) {
3085	>	if (sl != null)
3086	>	sl.red = false;
3087	>	xpr.red = true;
3088	>	root = rotateRight(root, xpr);
3089	>	xpr = (xp = x.parent) == null ?
3090	>	null : xp.right;
3091	>	}
3092	>	if (xpr != null) {
3093	>	xpr.red = (xp == null) ? false : xp.red;
3094	>	if ((sr = xpr.right) != null)
3095	>	sr.red = false;
3096	>	}
3097	>	if (xp != null) {
3098	>	xp.red = false;
3099	>	root = rotateLeft(root, xp);
3100	>	}
3101	>	x = root;
3102	>	}
3103	>	}
3104	>	}
3105	>	else { // symmetric
3106	>	if (xpl != null && xpl.red) {
3107	>	xpl.red = false;
3108	>	xp.red = true;
3109	>	root = rotateRight(root, xp);
3110	>	xpl = (xp = x.parent) == null ? null : xp.left;
3111	>	}
3112	>	if (xpl == null)
3113	>	x = xp;
3114	>	else {
3115	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3116	>	if ((sl == null || !sl.red) &&
3117	>	(sr == null || !sr.red)) {
3118	>	xpl.red = true;
3119	>	x = xp;
3120	>	}
3121	>	else {
3122	>	if (sl == null || !sl.red) {
3123	>	if (sr != null)
3124	>	sr.red = false;
3125	>	xpl.red = true;
3126	>	root = rotateLeft(root, xpl);
3127	>	xpl = (xp = x.parent) == null ?
3128	>	null : xp.left;
3129	>	}
3130	>	if (xpl != null) {
3131	>	xpl.red = (xp == null) ? false : xp.red;
3132	>	if ((sl = xpl.left) != null)
3133	>	sl.red = false;
3134	>	}
3135	>	if (xp != null) {
3136	>	xp.red = false;
3137	>	root = rotateRight(root, xp);
3138	>	}
3139	>	x = root;
3140	>	}
3141	>	}
3142	>	}
3143	>	}
3144	>	}
3145	>
3146	>	/**
3147	>	* Recursive invariant check
3148	>	*/
3149	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3150	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3151	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3152	>	if (tb != null && tb.next != t)
3153	>	return false;
3154	>	if (tn != null && tn.prev != t)
3155	>	return false;
3156	>	if (tp != null && t != tp.left && t != tp.right)
3157	>	return false;
3158	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3159	>	return false;
3160	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3161	>	return false;
3162	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3163	>	return false;
3164	>	if (tl != null && !checkInvariants(tl))
3165	>	return false;
3166	>	if (tr != null && !checkInvariants(tr))
3167	>	return false;
3168	>	return true;
3169	>	}
3170	>
3171	>	private static final sun.misc.Unsafe U;
3172	>	private static final long LOCKSTATE;
3173	>	static {
3174	>	try {
3175	>	U = sun.misc.Unsafe.getUnsafe();
3176	>	Class<?> k = TreeBin.class;
3177	>	LOCKSTATE = U.objectFieldOffset
3178	>	(k.getDeclaredField("lockState"));
3179	>	} catch (Exception e) {
3180	>	throw new Error(e);
3181	>	}
3182	>	}
3183	>	}
3184	>
3185	>	/* ----------------Table Traversal -------------- */
3186	>
3187	>	/**
3188	>	* Records the table, its length, and current traversal index for a
3189	>	* traverser that must process a region of a forwarded table before
3190	>	* proceeding with current table.
3191	>	*/
3192	>	static final class TableStack<K,V> {
3193	>	int length;
3194	>	int index;
3195	>	Node<K,V>[] tab;
3196	>	TableStack<K,V> next;
3197	>	}
3198	>
3199	>	/**
3200	>	* Encapsulates traversal for methods such as containsValue; also
3201	>	* serves as a base class for other iterators and spliterators.
3202	>	*
3203	>	* Method advance visits once each still-valid node that was
3204	>	* reachable upon iterator construction. It might miss some that
3205	>	* were added to a bin after the bin was visited, which is OK wrt
3206	>	* consistency guarantees. Maintaining this property in the face
3207	>	* of possible ongoing resizes requires a fair amount of
3208	>	* bookkeeping state that is difficult to optimize away amidst
3209	>	* volatile accesses.  Even so, traversal maintains reasonable
3210	>	* throughput.
3211	>	*
3212	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3213	>	* However, if the table has been resized, then all future steps
3214	>	* must traverse both the bin at the current index as well as at
3215	>	* (index + baseSize); and so on for further resizings. To
3216	>	* paranoically cope with potential sharing by users of iterators
3217	>	* across threads, iteration terminates if a bounds checks fails
3218	>	* for a table read.
3219	>	*/
3220	>	static class Traverser<K,V> {
3221	>	Node<K,V>[] tab;        // current table; updated if resized
3222	>	Node<K,V> next;         // the next entry to use
3223	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3224	>	int index;              // index of bin to use next
3225	>	int baseIndex;          // current index of initial table
3226	>	int baseLimit;          // index bound for initial table
3227	>	final int baseSize;     // initial table size
3228	>
3229	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3230	>	this.tab = tab;
3231	>	this.baseSize = size;
3232	>	this.baseIndex = this.index = index;
3233	>	this.baseLimit = limit;
3234	>	this.next = null;
3235	>	}
3236	>
3237	>	/**
3238	>	* Advances if possible, returning next valid node, or null if none.
3239	>	*/
3240	>	final Node<K,V> advance() {
3241	>	Node<K,V> e;
3242	>	if ((e = next) != null)
3243	>	e = e.next;
3244	>	for (;;) {
3245	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3246	>	if (e != null)
3247	>	return next = e;
3248	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3249	>	(n = t.length) <= (i = index) || i < 0)
3250	>	return next = null;
3251	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3252	>	if (e instanceof ForwardingNode) {
3253	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3254	>	e = null;
3255	>	pushState(t, i, n);
3256	>	continue;
3257	>	}
3258	>	else if (e instanceof TreeBin)
3259	>	e = ((TreeBin<K,V>)e).first;
3260	>	else
3261	>	e = null;
3262	>	}
3263	>	if (stack != null)
3264	>	recoverState(n);
3265	>	else if ((index = i + baseSize) >= n)
3266	>	index = ++baseIndex; // visit upper slots if present
3267	>	}
3268	>	}
3269	>
3270	>	/**
3271	>	* Save traversal state upon encountering a forwarding node.
3272	>	*/
3273	>	private void pushState(Node<K,V>[] t, int i, int n) {
3274	>	TableStack<K,V> s = spare;  // reuse if possible
3275	>	if (s != null)
3276	>	spare = s.next;
3277	>	else
3278	>	s = new TableStack<K,V>();
3279	>	s.tab = t;
3280	>	s.length = n;
3281	>	s.index = i;
3282	>	s.next = stack;
3283	>	stack = s;
3284	>	}
3285	>
3286	>	/**
3287	>	* Possibly pop traversal state
3288	>	*
3289	>	* @param n length of current table
3290	>	*/
3291	>	private void recoverState(int n) {
3292	>	TableStack<K,V> s; int len;
3293	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3294	>	n = len;
3295	>	index = s.index;
3296	>	tab = s.tab;
3297	>	s.tab = null;
3298	>	TableStack<K,V> next = s.next;
3299	>	s.next = spare; // save for reuse
3300	>	stack = next;
3301	>	spare = s;
3302	>	}
3303	>	if (s == null && (index += baseSize) >= n)
3304	>	index = ++baseIndex;
3305	>	}
3306	>	}
3307	>
3308	>	/**
3309	>	* Base of key, value, and entry Iterators. Adds fields to
3310	>	* Traverser to support iterator.remove.
3311	>	*/
3312	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3313	>	final ConcurrentHashMap<K,V> map;
3314	>	Node<K,V> lastReturned;
3315	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3316	>	ConcurrentHashMap<K,V> map) {
3317	>	super(tab, size, index, limit);
3318	>	this.map = map;
3319		advance();
1101	–	return lastReturned;
3320		}
3321
3322	<	public void remove() {
3323	<	if (lastReturned == null)
3322	>	public final boolean hasNext() { return next != null; }
3323	>	public final boolean hasMoreElements() { return next != null; }
3324	>
3325	>	public final void remove() {
3326	>	Node<K,V> p;
3327	>	if ((p = lastReturned) == null)
3328		throw new IllegalStateException();
1107	–	ConcurrentHashMap.this.remove(lastReturned.key);
3329		lastReturned = null;
3330	+	map.replaceNode(p.key, null, null);
3331		}
3332		}
3333
3334	<	final class KeyIterator
3335	<	extends HashIterator
3336	<	implements Iterator<K>, Enumeration<K>
3337	<	{
3338	<	public K next()        { return super.nextEntry().key; }
3339	<	public K nextElement() { return super.nextEntry().key; }
3334	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3335	>	implements Iterator<K>, Enumeration<K> {
3336	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3337	>	ConcurrentHashMap<K,V> map) {
3338	>	super(tab, index, size, limit, map);
3339	>	}
3340	>
3341	>	public final K next() {
3342	>	Node<K,V> p;
3343	>	if ((p = next) == null)
3344	>	throw new NoSuchElementException();
3345	>	K k = p.key;
3346	>	lastReturned = p;
3347	>	advance();
3348	>	return k;
3349	>	}
3350	>
3351	>	public final K nextElement() { return next(); }
3352		}
3353
3354	<	final class ValueIterator
3355	<	extends HashIterator
3356	<	implements Iterator<V>, Enumeration<V>
3357	<	{
3358	<	public V next()        { return super.nextEntry().value; }
3359	<	public V nextElement() { return super.nextEntry().value; }
3354	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3355	>	implements Iterator<V>, Enumeration<V> {
3356	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3357	>	ConcurrentHashMap<K,V> map) {
3358	>	super(tab, index, size, limit, map);
3359	>	}
3360	>
3361	>	public final V next() {
3362	>	Node<K,V> p;
3363	>	if ((p = next) == null)
3364	>	throw new NoSuchElementException();
3365	>	V v = p.val;
3366	>	lastReturned = p;
3367	>	advance();
3368	>	return v;
3369	>	}
3370	>
3371	>	public final V nextElement() { return next(); }
3372	>	}
3373	>
3374	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3375	>	implements Iterator<Map.Entry<K,V>> {
3376	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3377	>	ConcurrentHashMap<K,V> map) {
3378	>	super(tab, index, size, limit, map);
3379	>	}
3380	>
3381	>	public final Map.Entry<K,V> next() {
3382	>	Node<K,V> p;
3383	>	if ((p = next) == null)
3384	>	throw new NoSuchElementException();
3385	>	K k = p.key;
3386	>	V v = p.val;
3387	>	lastReturned = p;
3388	>	advance();
3389	>	return new MapEntry<K,V>(k, v, map);
3390	>	}
3391		}
3392
3393		/**
3394	<	* Custom Entry class used by EntryIterator.next(), that relays
1130	<	* setValue changes to the underlying map.
3394	>	* Exported Entry for EntryIterator
3395		*/
3396	<	final class WriteThroughEntry
3397	<	extends AbstractMap.SimpleEntry<K,V>
3398	<	{
3399	<	WriteThroughEntry(K k, V v) {
3400	<	super(k,v);
3396	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3397	>	final K key; // non-null
3398	>	V val;       // non-null
3399	>	final ConcurrentHashMap<K,V> map;
3400	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3401	>	this.key = key;
3402	>	this.val = val;
3403	>	this.map = map;
3404	>	}
3405	>	public K getKey()        { return key; }
3406	>	public V getValue()      { return val; }
3407	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3408	>	public String toString() { return key + "=" + val; }
3409	>
3410	>	public boolean equals(Object o) {
3411	>	Object k, v; Map.Entry<?,?> e;
3412	>	return ((o instanceof Map.Entry) &&
3413	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3414	>	(v = e.getValue()) != null &&
3415	>	(k == key || k.equals(key)) &&
3416	>	(v == val || v.equals(val)));
3417		}
3418
3419		/**
3420	<	* Set our entry's value and write through to the map. The
3421	<	* value to return is somewhat arbitrary here. Since a
3422	<	* WriteThroughEntry does not necessarily track asynchronous
3423	<	* changes, the most recent "previous" value could be
3424	<	* different from what we return (or could even have been
3425	<	* removed in which case the put will re-establish). We do not
1146	<	* and cannot guarantee more.
3420	>	* Sets our entry's value and writes through to the map. The
3421	>	* value to return is somewhat arbitrary here. Since we do not
3422	>	* necessarily track asynchronous changes, the most recent
3423	>	* "previous" value could be different from what we return (or
3424	>	* could even have been removed, in which case the put will
3425	>	* re-establish). We do not and cannot guarantee more.
3426		*/
3427	<	public V setValue(V value) {
3427	>	public V setValue(V value) {
3428		if (value == null) throw new NullPointerException();
3429	<	V v = super.setValue(value);
3430	<	ConcurrentHashMap.this.put(getKey(), value);
3429	>	V v = val;
3430	>	val = value;
3431	>	map.put(key, value);
3432		return v;
3433		}
3434		}
3435
3436	<	final class EntryIterator
3437	<	extends HashIterator
3438	<	implements Iterator<Entry<K,V>>
3439	<	{
3440	<	public Map.Entry<K,V> next() {
3441	<	HashEntry<K,V> e = super.nextEntry();
3442	<	return new WriteThroughEntry(e.key, e.value);
3436	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3437	>	implements Spliterator<K> {
3438	>	long est;               // size estimate
3439	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3440	>	long est) {
3441	>	super(tab, size, index, limit);
3442	>	this.est = est;
3443	>	}
3444	>
3445	>	public Spliterator<K> trySplit() {
3446	>	int i, f, h;
3447	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3448	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3449	>	f, est >>>= 1);
3450	>	}
3451	>
3452	>	public void forEachRemaining(Consumer<? super K> action) {
3453	>	if (action == null) throw new NullPointerException();
3454	>	for (Node<K,V> p; (p = advance()) != null;)
3455	>	action.accept(p.key);
3456	>	}
3457	>
3458	>	public boolean tryAdvance(Consumer<? super K> action) {
3459	>	if (action == null) throw new NullPointerException();
3460	>	Node<K,V> p;
3461	>	if ((p = advance()) == null)
3462	>	return false;
3463	>	action.accept(p.key);
3464	>	return true;
3465	>	}
3466	>
3467	>	public long estimateSize() { return est; }
3468	>
3469	>	public int characteristics() {
3470	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3471	>	Spliterator.NONNULL;
3472		}
3473		}
3474
3475	<	final class KeySet extends AbstractSet<K> {
3476	<	public Iterator<K> iterator() {
3477	<	return new KeyIterator();
3475	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3476	>	implements Spliterator<V> {
3477	>	long est;               // size estimate
3478	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3479	>	long est) {
3480	>	super(tab, size, index, limit);
3481	>	this.est = est;
3482	>	}
3483	>
3484	>	public Spliterator<V> trySplit() {
3485	>	int i, f, h;
3486	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3487	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3488	>	f, est >>>= 1);
3489	>	}
3490	>
3491	>	public void forEachRemaining(Consumer<? super V> action) {
3492	>	if (action == null) throw new NullPointerException();
3493	>	for (Node<K,V> p; (p = advance()) != null;)
3494	>	action.accept(p.val);
3495	>	}
3496	>
3497	>	public boolean tryAdvance(Consumer<? super V> action) {
3498	>	if (action == null) throw new NullPointerException();
3499	>	Node<K,V> p;
3500	>	if ((p = advance()) == null)
3501	>	return false;
3502	>	action.accept(p.val);
3503	>	return true;
3504		}
3505	<	public int size() {
3506	<	return ConcurrentHashMap.this.size();
3505	>
3506	>	public long estimateSize() { return est; }
3507	>
3508	>	public int characteristics() {
3509	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3510		}
3511	<	public boolean contains(Object o) {
3512	<	return ConcurrentHashMap.this.containsKey(o);
3511	>	}
3512	>
3513	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3514	>	implements Spliterator<Map.Entry<K,V>> {
3515	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3516	>	long est;               // size estimate
3517	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3518	>	long est, ConcurrentHashMap<K,V> map) {
3519	>	super(tab, size, index, limit);
3520	>	this.map = map;
3521	>	this.est = est;
3522	>	}
3523	>
3524	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3525	>	int i, f, h;
3526	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3527	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3528	>	f, est >>>= 1, map);
3529	>	}
3530	>
3531	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3532	>	if (action == null) throw new NullPointerException();
3533	>	for (Node<K,V> p; (p = advance()) != null; )
3534	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3535	>	}
3536	>
3537	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3538	>	if (action == null) throw new NullPointerException();
3539	>	Node<K,V> p;
3540	>	if ((p = advance()) == null)
3541	>	return false;
3542	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3543	>	return true;
3544		}
3545	<	public boolean remove(Object o) {
3546	<	return ConcurrentHashMap.this.remove(o) != null;
3545	>
3546	>	public long estimateSize() { return est; }
3547	>
3548	>	public int characteristics() {
3549	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3550	>	Spliterator.NONNULL;
3551		}
3552	<	public void clear() {
3553	<	ConcurrentHashMap.this.clear();
3552	>	}
3553	>
3554	>	// Parallel bulk operations
3555	>
3556	>	/**
3557	>	* Computes initial batch value for bulk tasks. The returned value
3558	>	* is approximately exp2 of the number of times (minus one) to
3559	>	* split task by two before executing leaf action. This value is
3560	>	* faster to compute and more convenient to use as a guide to
3561	>	* splitting than is the depth, since it is used while dividing by
3562	>	* two anyway.
3563	>	*/
3564	>	final int batchFor(long b) {
3565	>	long n;
3566	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3567	>	return 0;
3568	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3569	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3570	>	}
3571	>
3572	>	/**
3573	>	* Performs the given action for each (key, value).
3574	>	*
3575	>	* @param parallelismThreshold the (estimated) number of elements
3576	>	* needed for this operation to be executed in parallel
3577	>	* @param action the action
3578	>	* @since 1.8
3579	>	*/
3580	>	public void forEach(long parallelismThreshold,
3581	>	BiConsumer<? super K,? super V> action) {
3582	>	if (action == null) throw new NullPointerException();
3583	>	new ForEachMappingTask<K,V>
3584	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3585	>	action).invoke();
3586	>	}
3587	>
3588	>	/**
3589	>	* Performs the given action for each non-null transformation
3590	>	* of each (key, value).
3591	>	*
3592	>	* @param parallelismThreshold the (estimated) number of elements
3593	>	* needed for this operation to be executed in parallel
3594	>	* @param transformer a function returning the transformation
3595	>	* for an element, or null if there is no transformation (in
3596	>	* which case the action is not applied)
3597	>	* @param action the action
3598	>	* @param <U> the return type of the transformer
3599	>	* @since 1.8
3600	>	*/
3601	>	public <U> void forEach(long parallelismThreshold,
3602	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3603	>	Consumer<? super U> action) {
3604	>	if (transformer == null || action == null)
3605	>	throw new NullPointerException();
3606	>	new ForEachTransformedMappingTask<K,V,U>
3607	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3608	>	transformer, action).invoke();
3609	>	}
3610	>
3611	>	/**
3612	>	* Returns a non-null result from applying the given search
3613	>	* function on each (key, value), or null if none.  Upon
3614	>	* success, further element processing is suppressed and the
3615	>	* results of any other parallel invocations of the search
3616	>	* function are ignored.
3617	>	*
3618	>	* @param parallelismThreshold the (estimated) number of elements
3619	>	* needed for this operation to be executed in parallel
3620	>	* @param searchFunction a function returning a non-null
3621	>	* result on success, else null
3622	>	* @param <U> the return type of the search function
3623	>	* @return a non-null result from applying the given search
3624	>	* function on each (key, value), or null if none
3625	>	* @since 1.8
3626	>	*/
3627	>	public <U> U search(long parallelismThreshold,
3628	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3629	>	if (searchFunction == null) throw new NullPointerException();
3630	>	return new SearchMappingsTask<K,V,U>
3631	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3632	>	searchFunction, new AtomicReference<U>()).invoke();
3633	>	}
3634	>
3635	>	/**
3636	>	* Returns the result of accumulating the given transformation
3637	>	* of all (key, value) pairs using the given reducer to
3638	>	* combine values, or null if none.
3639	>	*
3640	>	* @param parallelismThreshold the (estimated) number of elements
3641	>	* needed for this operation to be executed in parallel
3642	>	* @param transformer a function returning the transformation
3643	>	* for an element, or null if there is no transformation (in
3644	>	* which case it is not combined)
3645	>	* @param reducer a commutative associative combining function
3646	>	* @param <U> the return type of the transformer
3647	>	* @return the result of accumulating the given transformation
3648	>	* of all (key, value) pairs
3649	>	* @since 1.8
3650	>	*/
3651	>	public <U> U reduce(long parallelismThreshold,
3652	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3653	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3654	>	if (transformer == null || reducer == null)
3655	>	throw new NullPointerException();
3656	>	return new MapReduceMappingsTask<K,V,U>
3657	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3658	>	null, transformer, reducer).invoke();
3659	>	}
3660	>
3661	>	/**
3662	>	* Returns the result of accumulating the given transformation
3663	>	* of all (key, value) pairs using the given reducer to
3664	>	* combine values, and the given basis as an identity value.
3665	>	*
3666	>	* @param parallelismThreshold the (estimated) number of elements
3667	>	* needed for this operation to be executed in parallel
3668	>	* @param transformer a function returning the transformation
3669	>	* for an element
3670	>	* @param basis the identity (initial default value) for the reduction
3671	>	* @param reducer a commutative associative combining function
3672	>	* @return the result of accumulating the given transformation
3673	>	* of all (key, value) pairs
3674	>	* @since 1.8
3675	>	*/
3676	>	public double reduceToDouble(long parallelismThreshold,
3677	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3678	>	double basis,
3679	>	DoubleBinaryOperator reducer) {
3680	>	if (transformer == null || reducer == null)
3681	>	throw new NullPointerException();
3682	>	return new MapReduceMappingsToDoubleTask<K,V>
3683	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3684	>	null, transformer, basis, reducer).invoke();
3685	>	}
3686	>
3687	>	/**
3688	>	* Returns the result of accumulating the given transformation
3689	>	* of all (key, value) pairs using the given reducer to
3690	>	* combine values, and the given basis as an identity value.
3691	>	*
3692	>	* @param parallelismThreshold the (estimated) number of elements
3693	>	* needed for this operation to be executed in parallel
3694	>	* @param transformer a function returning the transformation
3695	>	* for an element
3696	>	* @param basis the identity (initial default value) for the reduction
3697	>	* @param reducer a commutative associative combining function
3698	>	* @return the result of accumulating the given transformation
3699	>	* of all (key, value) pairs
3700	>	* @since 1.8
3701	>	*/
3702	>	public long reduceToLong(long parallelismThreshold,
3703	>	ToLongBiFunction<? super K, ? super V> transformer,
3704	>	long basis,
3705	>	LongBinaryOperator reducer) {
3706	>	if (transformer == null || reducer == null)
3707	>	throw new NullPointerException();
3708	>	return new MapReduceMappingsToLongTask<K,V>
3709	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3710	>	null, transformer, basis, reducer).invoke();
3711	>	}
3712	>
3713	>	/**
3714	>	* Returns the result of accumulating the given transformation
3715	>	* of all (key, value) pairs using the given reducer to
3716	>	* combine values, and the given basis as an identity value.
3717	>	*
3718	>	* @param parallelismThreshold the (estimated) number of elements
3719	>	* needed for this operation to be executed in parallel
3720	>	* @param transformer a function returning the transformation
3721	>	* for an element
3722	>	* @param basis the identity (initial default value) for the reduction
3723	>	* @param reducer a commutative associative combining function
3724	>	* @return the result of accumulating the given transformation
3725	>	* of all (key, value) pairs
3726	>	* @since 1.8
3727	>	*/
3728	>	public int reduceToInt(long parallelismThreshold,
3729	>	ToIntBiFunction<? super K, ? super V> transformer,
3730	>	int basis,
3731	>	IntBinaryOperator reducer) {
3732	>	if (transformer == null || reducer == null)
3733	>	throw new NullPointerException();
3734	>	return new MapReduceMappingsToIntTask<K,V>
3735	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3736	>	null, transformer, basis, reducer).invoke();
3737	>	}
3738	>
3739	>	/**
3740	>	* Performs the given action for each key.
3741	>	*
3742	>	* @param parallelismThreshold the (estimated) number of elements
3743	>	* needed for this operation to be executed in parallel
3744	>	* @param action the action
3745	>	* @since 1.8
3746	>	*/
3747	>	public void forEachKey(long parallelismThreshold,
3748	>	Consumer<? super K> action) {
3749	>	if (action == null) throw new NullPointerException();
3750	>	new ForEachKeyTask<K,V>
3751	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3752	>	action).invoke();
3753	>	}
3754	>
3755	>	/**
3756	>	* Performs the given action for each non-null transformation
3757	>	* of each key.
3758	>	*
3759	>	* @param parallelismThreshold the (estimated) number of elements
3760	>	* needed for this operation to be executed in parallel
3761	>	* @param transformer a function returning the transformation
3762	>	* for an element, or null if there is no transformation (in
3763	>	* which case the action is not applied)
3764	>	* @param action the action
3765	>	* @param <U> the return type of the transformer
3766	>	* @since 1.8
3767	>	*/
3768	>	public <U> void forEachKey(long parallelismThreshold,
3769	>	Function<? super K, ? extends U> transformer,
3770	>	Consumer<? super U> action) {
3771	>	if (transformer == null || action == null)
3772	>	throw new NullPointerException();
3773	>	new ForEachTransformedKeyTask<K,V,U>
3774	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3775	>	transformer, action).invoke();
3776	>	}
3777	>
3778	>	/**
3779	>	* Returns a non-null result from applying the given search
3780	>	* function on each key, or null if none. Upon success,
3781	>	* further element processing is suppressed and the results of
3782	>	* any other parallel invocations of the search function are
3783	>	* ignored.
3784	>	*
3785	>	* @param parallelismThreshold the (estimated) number of elements
3786	>	* needed for this operation to be executed in parallel
3787	>	* @param searchFunction a function returning a non-null
3788	>	* result on success, else null
3789	>	* @param <U> the return type of the search function
3790	>	* @return a non-null result from applying the given search
3791	>	* function on each key, or null if none
3792	>	* @since 1.8
3793	>	*/
3794	>	public <U> U searchKeys(long parallelismThreshold,
3795	>	Function<? super K, ? extends U> searchFunction) {
3796	>	if (searchFunction == null) throw new NullPointerException();
3797	>	return new SearchKeysTask<K,V,U>
3798	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3799	>	searchFunction, new AtomicReference<U>()).invoke();
3800	>	}
3801	>
3802	>	/**
3803	>	* Returns the result of accumulating all keys using the given
3804	>	* reducer to combine values, or null if none.
3805	>	*
3806	>	* @param parallelismThreshold the (estimated) number of elements
3807	>	* needed for this operation to be executed in parallel
3808	>	* @param reducer a commutative associative combining function
3809	>	* @return the result of accumulating all keys using the given
3810	>	* reducer to combine values, or null if none
3811	>	* @since 1.8
3812	>	*/
3813	>	public K reduceKeys(long parallelismThreshold,
3814	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3815	>	if (reducer == null) throw new NullPointerException();
3816	>	return new ReduceKeysTask<K,V>
3817	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3818	>	null, reducer).invoke();
3819	>	}
3820	>
3821	>	/**
3822	>	* Returns the result of accumulating the given transformation
3823	>	* of all keys using the given reducer to combine values, or
3824	>	* null if none.
3825	>	*
3826	>	* @param parallelismThreshold the (estimated) number of elements
3827	>	* needed for this operation to be executed in parallel
3828	>	* @param transformer a function returning the transformation
3829	>	* for an element, or null if there is no transformation (in
3830	>	* which case it is not combined)
3831	>	* @param reducer a commutative associative combining function
3832	>	* @param <U> the return type of the transformer
3833	>	* @return the result of accumulating the given transformation
3834	>	* of all keys
3835	>	* @since 1.8
3836	>	*/
3837	>	public <U> U reduceKeys(long parallelismThreshold,
3838	>	Function<? super K, ? extends U> transformer,
3839	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3840	>	if (transformer == null || reducer == null)
3841	>	throw new NullPointerException();
3842	>	return new MapReduceKeysTask<K,V,U>
3843	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3844	>	null, transformer, reducer).invoke();
3845	>	}
3846	>
3847	>	/**
3848	>	* Returns the result of accumulating the given transformation
3849	>	* of all keys using the given reducer to combine values, and
3850	>	* the given basis as an identity value.
3851	>	*
3852	>	* @param parallelismThreshold the (estimated) number of elements
3853	>	* needed for this operation to be executed in parallel
3854	>	* @param transformer a function returning the transformation
3855	>	* for an element
3856	>	* @param basis the identity (initial default value) for the reduction
3857	>	* @param reducer a commutative associative combining function
3858	>	* @return the result of accumulating the given transformation
3859	>	* of all keys
3860	>	* @since 1.8
3861	>	*/
3862	>	public double reduceKeysToDouble(long parallelismThreshold,
3863	>	ToDoubleFunction<? super K> transformer,
3864	>	double basis,
3865	>	DoubleBinaryOperator reducer) {
3866	>	if (transformer == null || reducer == null)
3867	>	throw new NullPointerException();
3868	>	return new MapReduceKeysToDoubleTask<K,V>
3869	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3870	>	null, transformer, basis, reducer).invoke();
3871	>	}
3872	>
3873	>	/**
3874	>	* Returns the result of accumulating the given transformation
3875	>	* of all keys using the given reducer to combine values, and
3876	>	* the given basis as an identity value.
3877	>	*
3878	>	* @param parallelismThreshold the (estimated) number of elements
3879	>	* needed for this operation to be executed in parallel
3880	>	* @param transformer a function returning the transformation
3881	>	* for an element
3882	>	* @param basis the identity (initial default value) for the reduction
3883	>	* @param reducer a commutative associative combining function
3884	>	* @return the result of accumulating the given transformation
3885	>	* of all keys
3886	>	* @since 1.8
3887	>	*/
3888	>	public long reduceKeysToLong(long parallelismThreshold,
3889	>	ToLongFunction<? super K> transformer,
3890	>	long basis,
3891	>	LongBinaryOperator reducer) {
3892	>	if (transformer == null || reducer == null)
3893	>	throw new NullPointerException();
3894	>	return new MapReduceKeysToLongTask<K,V>
3895	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3896	>	null, transformer, basis, reducer).invoke();
3897	>	}
3898	>
3899	>	/**
3900	>	* Returns the result of accumulating the given transformation
3901	>	* of all keys using the given reducer to combine values, and
3902	>	* the given basis as an identity value.
3903	>	*
3904	>	* @param parallelismThreshold the (estimated) number of elements
3905	>	* needed for this operation to be executed in parallel
3906	>	* @param transformer a function returning the transformation
3907	>	* for an element
3908	>	* @param basis the identity (initial default value) for the reduction
3909	>	* @param reducer a commutative associative combining function
3910	>	* @return the result of accumulating the given transformation
3911	>	* of all keys
3912	>	* @since 1.8
3913	>	*/
3914	>	public int reduceKeysToInt(long parallelismThreshold,
3915	>	ToIntFunction<? super K> transformer,
3916	>	int basis,
3917	>	IntBinaryOperator reducer) {
3918	>	if (transformer == null || reducer == null)
3919	>	throw new NullPointerException();
3920	>	return new MapReduceKeysToIntTask<K,V>
3921	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3922	>	null, transformer, basis, reducer).invoke();
3923	>	}
3924	>
3925	>	/**
3926	>	* Performs the given action for each value.
3927	>	*
3928	>	* @param parallelismThreshold the (estimated) number of elements
3929	>	* needed for this operation to be executed in parallel
3930	>	* @param action the action
3931	>	* @since 1.8
3932	>	*/
3933	>	public void forEachValue(long parallelismThreshold,
3934	>	Consumer<? super V> action) {
3935	>	if (action == null)
3936	>	throw new NullPointerException();
3937	>	new ForEachValueTask<K,V>
3938	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3939	>	action).invoke();
3940	>	}
3941	>
3942	>	/**
3943	>	* Performs the given action for each non-null transformation
3944	>	* of each value.
3945	>	*
3946	>	* @param parallelismThreshold the (estimated) number of elements
3947	>	* needed for this operation to be executed in parallel
3948	>	* @param transformer a function returning the transformation
3949	>	* for an element, or null if there is no transformation (in
3950	>	* which case the action is not applied)
3951	>	* @param action the action
3952	>	* @param <U> the return type of the transformer
3953	>	* @since 1.8
3954	>	*/
3955	>	public <U> void forEachValue(long parallelismThreshold,
3956	>	Function<? super V, ? extends U> transformer,
3957	>	Consumer<? super U> action) {
3958	>	if (transformer == null || action == null)
3959	>	throw new NullPointerException();
3960	>	new ForEachTransformedValueTask<K,V,U>
3961	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3962	>	transformer, action).invoke();
3963	>	}
3964	>
3965	>	/**
3966	>	* Returns a non-null result from applying the given search
3967	>	* function on each value, or null if none.  Upon success,
3968	>	* further element processing is suppressed and the results of
3969	>	* any other parallel invocations of the search function are
3970	>	* ignored.
3971	>	*
3972	>	* @param parallelismThreshold the (estimated) number of elements
3973	>	* needed for this operation to be executed in parallel
3974	>	* @param searchFunction a function returning a non-null
3975	>	* result on success, else null
3976	>	* @param <U> the return type of the search function
3977	>	* @return a non-null result from applying the given search
3978	>	* function on each value, or null if none
3979	>	* @since 1.8
3980	>	*/
3981	>	public <U> U searchValues(long parallelismThreshold,
3982	>	Function<? super V, ? extends U> searchFunction) {
3983	>	if (searchFunction == null) throw new NullPointerException();
3984	>	return new SearchValuesTask<K,V,U>
3985	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3986	>	searchFunction, new AtomicReference<U>()).invoke();
3987	>	}
3988	>
3989	>	/**
3990	>	* Returns the result of accumulating all values using the
3991	>	* given reducer to combine values, or null if none.
3992	>	*
3993	>	* @param parallelismThreshold the (estimated) number of elements
3994	>	* needed for this operation to be executed in parallel
3995	>	* @param reducer a commutative associative combining function
3996	>	* @return the result of accumulating all values
3997	>	* @since 1.8
3998	>	*/
3999	>	public V reduceValues(long parallelismThreshold,
4000	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4001	>	if (reducer == null) throw new NullPointerException();
4002	>	return new ReduceValuesTask<K,V>
4003	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4004	>	null, reducer).invoke();
4005	>	}
4006	>
4007	>	/**
4008	>	* Returns the result of accumulating the given transformation
4009	>	* of all values using the given reducer to combine values, or
4010	>	* null if none.
4011	>	*
4012	>	* @param parallelismThreshold the (estimated) number of elements
4013	>	* needed for this operation to be executed in parallel
4014	>	* @param transformer a function returning the transformation
4015	>	* for an element, or null if there is no transformation (in
4016	>	* which case it is not combined)
4017	>	* @param reducer a commutative associative combining function
4018	>	* @param <U> the return type of the transformer
4019	>	* @return the result of accumulating the given transformation
4020	>	* of all values
4021	>	* @since 1.8
4022	>	*/
4023	>	public <U> U reduceValues(long parallelismThreshold,
4024	>	Function<? super V, ? extends U> transformer,
4025	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4026	>	if (transformer == null || reducer == null)
4027	>	throw new NullPointerException();
4028	>	return new MapReduceValuesTask<K,V,U>
4029	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4030	>	null, transformer, reducer).invoke();
4031	>	}
4032	>
4033	>	/**
4034	>	* Returns the result of accumulating the given transformation
4035	>	* of all values using the given reducer to combine values,
4036	>	* and the given basis as an identity value.
4037	>	*
4038	>	* @param parallelismThreshold the (estimated) number of elements
4039	>	* needed for this operation to be executed in parallel
4040	>	* @param transformer a function returning the transformation
4041	>	* for an element
4042	>	* @param basis the identity (initial default value) for the reduction
4043	>	* @param reducer a commutative associative combining function
4044	>	* @return the result of accumulating the given transformation
4045	>	* of all values
4046	>	* @since 1.8
4047	>	*/
4048	>	public double reduceValuesToDouble(long parallelismThreshold,
4049	>	ToDoubleFunction<? super V> transformer,
4050	>	double basis,
4051	>	DoubleBinaryOperator reducer) {
4052	>	if (transformer == null || reducer == null)
4053	>	throw new NullPointerException();
4054	>	return new MapReduceValuesToDoubleTask<K,V>
4055	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4056	>	null, transformer, basis, reducer).invoke();
4057	>	}
4058	>
4059	>	/**
4060	>	* Returns the result of accumulating the given transformation
4061	>	* of all values using the given reducer to combine values,
4062	>	* and the given basis as an identity value.
4063	>	*
4064	>	* @param parallelismThreshold the (estimated) number of elements
4065	>	* needed for this operation to be executed in parallel
4066	>	* @param transformer a function returning the transformation
4067	>	* for an element
4068	>	* @param basis the identity (initial default value) for the reduction
4069	>	* @param reducer a commutative associative combining function
4070	>	* @return the result of accumulating the given transformation
4071	>	* of all values
4072	>	* @since 1.8
4073	>	*/
4074	>	public long reduceValuesToLong(long parallelismThreshold,
4075	>	ToLongFunction<? super V> transformer,
4076	>	long basis,
4077	>	LongBinaryOperator reducer) {
4078	>	if (transformer == null || reducer == null)
4079	>	throw new NullPointerException();
4080	>	return new MapReduceValuesToLongTask<K,V>
4081	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4082	>	null, transformer, basis, reducer).invoke();
4083	>	}
4084	>
4085	>	/**
4086	>	* Returns the result of accumulating the given transformation
4087	>	* of all values using the given reducer to combine values,
4088	>	* and the given basis as an identity value.
4089	>	*
4090	>	* @param parallelismThreshold the (estimated) number of elements
4091	>	* needed for this operation to be executed in parallel
4092	>	* @param transformer a function returning the transformation
4093	>	* for an element
4094	>	* @param basis the identity (initial default value) for the reduction
4095	>	* @param reducer a commutative associative combining function
4096	>	* @return the result of accumulating the given transformation
4097	>	* of all values
4098	>	* @since 1.8
4099	>	*/
4100	>	public int reduceValuesToInt(long parallelismThreshold,
4101	>	ToIntFunction<? super V> transformer,
4102	>	int basis,
4103	>	IntBinaryOperator reducer) {
4104	>	if (transformer == null || reducer == null)
4105	>	throw new NullPointerException();
4106	>	return new MapReduceValuesToIntTask<K,V>
4107	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4108	>	null, transformer, basis, reducer).invoke();
4109	>	}
4110	>
4111	>	/**
4112	>	* Performs the given action for each entry.
4113	>	*
4114	>	* @param parallelismThreshold the (estimated) number of elements
4115	>	* needed for this operation to be executed in parallel
4116	>	* @param action the action
4117	>	* @since 1.8
4118	>	*/
4119	>	public void forEachEntry(long parallelismThreshold,
4120	>	Consumer<? super Map.Entry<K,V>> action) {
4121	>	if (action == null) throw new NullPointerException();
4122	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4123	>	action).invoke();
4124	>	}
4125	>
4126	>	/**
4127	>	* Performs the given action for each non-null transformation
4128	>	* of each entry.
4129	>	*
4130	>	* @param parallelismThreshold the (estimated) number of elements
4131	>	* needed for this operation to be executed in parallel
4132	>	* @param transformer a function returning the transformation
4133	>	* for an element, or null if there is no transformation (in
4134	>	* which case the action is not applied)
4135	>	* @param action the action
4136	>	* @param <U> the return type of the transformer
4137	>	* @since 1.8
4138	>	*/
4139	>	public <U> void forEachEntry(long parallelismThreshold,
4140	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4141	>	Consumer<? super U> action) {
4142	>	if (transformer == null || action == null)
4143	>	throw new NullPointerException();
4144	>	new ForEachTransformedEntryTask<K,V,U>
4145	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4146	>	transformer, action).invoke();
4147	>	}
4148	>
4149	>	/**
4150	>	* Returns a non-null result from applying the given search
4151	>	* function on each entry, or null if none.  Upon success,
4152	>	* further element processing is suppressed and the results of
4153	>	* any other parallel invocations of the search function are
4154	>	* ignored.
4155	>	*
4156	>	* @param parallelismThreshold the (estimated) number of elements
4157	>	* needed for this operation to be executed in parallel
4158	>	* @param searchFunction a function returning a non-null
4159	>	* result on success, else null
4160	>	* @param <U> the return type of the search function
4161	>	* @return a non-null result from applying the given search
4162	>	* function on each entry, or null if none
4163	>	* @since 1.8
4164	>	*/
4165	>	public <U> U searchEntries(long parallelismThreshold,
4166	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4167	>	if (searchFunction == null) throw new NullPointerException();
4168	>	return new SearchEntriesTask<K,V,U>
4169	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4170	>	searchFunction, new AtomicReference<U>()).invoke();
4171	>	}
4172	>
4173	>	/**
4174	>	* Returns the result of accumulating all entries using the
4175	>	* given reducer to combine values, or null if none.
4176	>	*
4177	>	* @param parallelismThreshold the (estimated) number of elements
4178	>	* needed for this operation to be executed in parallel
4179	>	* @param reducer a commutative associative combining function
4180	>	* @return the result of accumulating all entries
4181	>	* @since 1.8
4182	>	*/
4183	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4184	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4185	>	if (reducer == null) throw new NullPointerException();
4186	>	return new ReduceEntriesTask<K,V>
4187	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4188	>	null, reducer).invoke();
4189	>	}
4190	>
4191	>	/**
4192	>	* Returns the result of accumulating the given transformation
4193	>	* of all entries using the given reducer to combine values,
4194	>	* or null if none.
4195	>	*
4196	>	* @param parallelismThreshold the (estimated) number of elements
4197	>	* needed for this operation to be executed in parallel
4198	>	* @param transformer a function returning the transformation
4199	>	* for an element, or null if there is no transformation (in
4200	>	* which case it is not combined)
4201	>	* @param reducer a commutative associative combining function
4202	>	* @param <U> the return type of the transformer
4203	>	* @return the result of accumulating the given transformation
4204	>	* of all entries
4205	>	* @since 1.8
4206	>	*/
4207	>	public <U> U reduceEntries(long parallelismThreshold,
4208	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4209	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4210	>	if (transformer == null || reducer == null)
4211	>	throw new NullPointerException();
4212	>	return new MapReduceEntriesTask<K,V,U>
4213	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4214	>	null, transformer, reducer).invoke();
4215	>	}
4216	>
4217	>	/**
4218	>	* Returns the result of accumulating the given transformation
4219	>	* of all entries using the given reducer to combine values,
4220	>	* and the given basis as an identity value.
4221	>	*
4222	>	* @param parallelismThreshold the (estimated) number of elements
4223	>	* needed for this operation to be executed in parallel
4224	>	* @param transformer a function returning the transformation
4225	>	* for an element
4226	>	* @param basis the identity (initial default value) for the reduction
4227	>	* @param reducer a commutative associative combining function
4228	>	* @return the result of accumulating the given transformation
4229	>	* of all entries
4230	>	* @since 1.8
4231	>	*/
4232	>	public double reduceEntriesToDouble(long parallelismThreshold,
4233	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4234	>	double basis,
4235	>	DoubleBinaryOperator reducer) {
4236	>	if (transformer == null || reducer == null)
4237	>	throw new NullPointerException();
4238	>	return new MapReduceEntriesToDoubleTask<K,V>
4239	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4240	>	null, transformer, basis, reducer).invoke();
4241	>	}
4242	>
4243	>	/**
4244	>	* Returns the result of accumulating the given transformation
4245	>	* of all entries using the given reducer to combine values,
4246	>	* and the given basis as an identity value.
4247	>	*
4248	>	* @param parallelismThreshold the (estimated) number of elements
4249	>	* needed for this operation to be executed in parallel
4250	>	* @param transformer a function returning the transformation
4251	>	* for an element
4252	>	* @param basis the identity (initial default value) for the reduction
4253	>	* @param reducer a commutative associative combining function
4254	>	* @return the result of accumulating the given transformation
4255	>	* of all entries
4256	>	* @since 1.8
4257	>	*/
4258	>	public long reduceEntriesToLong(long parallelismThreshold,
4259	>	ToLongFunction<Map.Entry<K,V>> transformer,
4260	>	long basis,
4261	>	LongBinaryOperator reducer) {
4262	>	if (transformer == null || reducer == null)
4263	>	throw new NullPointerException();
4264	>	return new MapReduceEntriesToLongTask<K,V>
4265	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4266	>	null, transformer, basis, reducer).invoke();
4267	>	}
4268	>
4269	>	/**
4270	>	* Returns the result of accumulating the given transformation
4271	>	* of all entries using the given reducer to combine values,
4272	>	* and the given basis as an identity value.
4273	>	*
4274	>	* @param parallelismThreshold the (estimated) number of elements
4275	>	* needed for this operation to be executed in parallel
4276	>	* @param transformer a function returning the transformation
4277	>	* for an element
4278	>	* @param basis the identity (initial default value) for the reduction
4279	>	* @param reducer a commutative associative combining function
4280	>	* @return the result of accumulating the given transformation
4281	>	* of all entries
4282	>	* @since 1.8
4283	>	*/
4284	>	public int reduceEntriesToInt(long parallelismThreshold,
4285	>	ToIntFunction<Map.Entry<K,V>> transformer,
4286	>	int basis,
4287	>	IntBinaryOperator reducer) {
4288	>	if (transformer == null || reducer == null)
4289	>	throw new NullPointerException();
4290	>	return new MapReduceEntriesToIntTask<K,V>
4291	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4292	>	null, transformer, basis, reducer).invoke();
4293	>	}
4294	>
4295	>
4296	>	/* ----------------Views -------------- */
4297	>
4298	>	/**
4299	>	* Base class for views.
4300	>	*/
4301	>	abstract static class CollectionView<K,V,E>
4302	>	implements Collection<E>, java.io.Serializable {
4303	>	private static final long serialVersionUID = 7249069246763182397L;
4304	>	final ConcurrentHashMap<K,V> map;
4305	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4306	>
4307	>	/**
4308	>	* Returns the map backing this view.
4309	>	*
4310	>	* @return the map backing this view
4311	>	*/
4312	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4313	>
4314	>	/**
4315	>	* Removes all of the elements from this view, by removing all
4316	>	* the mappings from the map backing this view.
4317	>	*/
4318	>	public final void clear()      { map.clear(); }
4319	>	public final int size()        { return map.size(); }
4320	>	public final boolean isEmpty() { return map.isEmpty(); }
4321	>
4322	>	// implementations below rely on concrete classes supplying these
4323	>	// abstract methods
4324	>	/**
4325	>	* Returns an iterator over the elements in this collection.
4326	>	*
4327	>	* <p>The returned iterator is
4328	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4329	>	*
4330	>	* @return an iterator over the elements in this collection
4331	>	*/
4332	>	public abstract Iterator<E> iterator();
4333	>	public abstract boolean contains(Object o);
4334	>	public abstract boolean remove(Object o);
4335	>
4336	>	private static final String oomeMsg = "Required array size too large";
4337	>
4338	>	public final Object[] toArray() {
4339	>	long sz = map.mappingCount();
4340	>	if (sz > MAX_ARRAY_SIZE)
4341	>	throw new OutOfMemoryError(oomeMsg);
4342	>	int n = (int)sz;
4343	>	Object[] r = new Object[n];
4344	>	int i = 0;
4345	>	for (E e : this) {
4346	>	if (i == n) {
4347	>	if (n >= MAX_ARRAY_SIZE)
4348	>	throw new OutOfMemoryError(oomeMsg);
4349	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4350	>	n = MAX_ARRAY_SIZE;
4351	>	else
4352	>	n += (n >>> 1) + 1;
4353	>	r = Arrays.copyOf(r, n);
4354	>	}
4355	>	r[i++] = e;
4356	>	}
4357	>	return (i == n) ? r : Arrays.copyOf(r, i);
4358	>	}
4359	>
4360	>	@SuppressWarnings("unchecked")
4361	>	public final <T> T[] toArray(T[] a) {
4362	>	long sz = map.mappingCount();
4363	>	if (sz > MAX_ARRAY_SIZE)
4364	>	throw new OutOfMemoryError(oomeMsg);
4365	>	int m = (int)sz;
4366	>	T[] r = (a.length >= m) ? a :
4367	>	(T[])java.lang.reflect.Array
4368	>	.newInstance(a.getClass().getComponentType(), m);
4369	>	int n = r.length;
4370	>	int i = 0;
4371	>	for (E e : this) {
4372	>	if (i == n) {
4373	>	if (n >= MAX_ARRAY_SIZE)
4374	>	throw new OutOfMemoryError(oomeMsg);
4375	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4376	>	n = MAX_ARRAY_SIZE;
4377	>	else
4378	>	n += (n >>> 1) + 1;
4379	>	r = Arrays.copyOf(r, n);
4380	>	}
4381	>	r[i++] = (T)e;
4382	>	}
4383	>	if (a == r && i < n) {
4384	>	r[i] = null; // null-terminate
4385	>	return r;
4386	>	}
4387	>	return (i == n) ? r : Arrays.copyOf(r, i);
4388	>	}
4389	>
4390	>	/**
4391	>	* Returns a string representation of this collection.
4392	>	* The string representation consists of the string representations
4393	>	* of the collection's elements in the order they are returned by
4394	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4395	>	* Adjacent elements are separated by the characters {@code ", "}
4396	>	* (comma and space).  Elements are converted to strings as by
4397	>	* {@link String#valueOf(Object)}.
4398	>	*
4399	>	* @return a string representation of this collection
4400	>	*/
4401	>	public final String toString() {
4402	>	StringBuilder sb = new StringBuilder();
4403	>	sb.append('[');
4404	>	Iterator<E> it = iterator();
4405	>	if (it.hasNext()) {
4406	>	for (;;) {
4407	>	Object e = it.next();
4408	>	sb.append(e == this ? "(this Collection)" : e);
4409	>	if (!it.hasNext())
4410	>	break;
4411	>	sb.append(',').append(' ');
4412	>	}
4413	>	}
4414	>	return sb.append(']').toString();
4415	>	}
4416	>
4417	>	public final boolean containsAll(Collection<?> c) {
4418	>	if (c != this) {
4419	>	for (Object e : c) {
4420	>	if (e == null || !contains(e))
4421	>	return false;
4422	>	}
4423	>	}
4424	>	return true;
4425	>	}
4426	>
4427	>	public final boolean removeAll(Collection<?> c) {
4428	>	boolean modified = false;
4429	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4430	>	if (c.contains(it.next())) {
4431	>	it.remove();
4432	>	modified = true;
4433	>	}
4434	>	}
4435	>	return modified;
4436	>	}
4437	>
4438	>	public final boolean retainAll(Collection<?> c) {
4439	>	boolean modified = false;
4440	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4441	>	if (!c.contains(it.next())) {
4442	>	it.remove();
4443	>	modified = true;
4444	>	}
4445	>	}
4446	>	return modified;
4447		}
4448	+
4449		}
4450
4451	<	final class Values extends AbstractCollection<V> {
4452	<	public Iterator<V> iterator() {
4453	<	return new ValueIterator();
4451	>	/**
4452	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4453	>	* which additions may optionally be enabled by mapping to a
4454	>	* common value.  This class cannot be directly instantiated.
4455	>	* See {@link #keySet() keySet()},
4456	>	* {@link #keySet(Object) keySet(V)},
4457	>	* {@link #newKeySet() newKeySet()},
4458	>	* {@link #newKeySet(int) newKeySet(int)}.
4459	>	*
4460	>	* @since 1.8
4461	>	*/
4462	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4463	>	implements Set<K>, java.io.Serializable {
4464	>	private static final long serialVersionUID = 7249069246763182397L;
4465	>	private final V value;
4466	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4467	>	super(map);
4468	>	this.value = value;
4469		}
4470	<	public int size() {
4471	<	return ConcurrentHashMap.this.size();
4470	>
4471	>	/**
4472	>	* Returns the default mapped value for additions,
4473	>	* or {@code null} if additions are not supported.
4474	>	*
4475	>	* @return the default mapped value for additions, or {@code null}
4476	>	* if not supported
4477	>	*/
4478	>	public V getMappedValue() { return value; }
4479	>
4480	>	/**
4481	>	* {@inheritDoc}
4482	>	* @throws NullPointerException if the specified key is null
4483	>	*/
4484	>	public boolean contains(Object o) { return map.containsKey(o); }
4485	>
4486	>	/**
4487	>	* Removes the key from this map view, by removing the key (and its
4488	>	* corresponding value) from the backing map.  This method does
4489	>	* nothing if the key is not in the map.
4490	>	*
4491	>	* @param  o the key to be removed from the backing map
4492	>	* @return {@code true} if the backing map contained the specified key
4493	>	* @throws NullPointerException if the specified key is null
4494	>	*/
4495	>	public boolean remove(Object o) { return map.remove(o) != null; }
4496	>
4497	>	/**
4498	>	* @return an iterator over the keys of the backing map
4499	>	*/
4500	>	public Iterator<K> iterator() {
4501	>	Node<K,V>[] t;
4502	>	ConcurrentHashMap<K,V> m = map;
4503	>	int f = (t = m.table) == null ? 0 : t.length;
4504	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4505		}
4506	<	public boolean contains(Object o) {
4507	<	return ConcurrentHashMap.this.containsValue(o);
4506	>
4507	>	/**
4508	>	* Adds the specified key to this set view by mapping the key to
4509	>	* the default mapped value in the backing map, if defined.
4510	>	*
4511	>	* @param e key to be added
4512	>	* @return {@code true} if this set changed as a result of the call
4513	>	* @throws NullPointerException if the specified key is null
4514	>	* @throws UnsupportedOperationException if no default mapped value
4515	>	* for additions was provided
4516	>	*/
4517	>	public boolean add(K e) {
4518	>	V v;
4519	>	if ((v = value) == null)
4520	>	throw new UnsupportedOperationException();
4521	>	return map.putVal(e, v, true) == null;
4522		}
4523	<	public void clear() {
4524	<	ConcurrentHashMap.this.clear();
4523	>
4524	>	/**
4525	>	* Adds all of the elements in the specified collection to this set,
4526	>	* as if by calling {@link #add} on each one.
4527	>	*
4528	>	* @param c the elements to be inserted into this set
4529	>	* @return {@code true} if this set changed as a result of the call
4530	>	* @throws NullPointerException if the collection or any of its
4531	>	* elements are {@code null}
4532	>	* @throws UnsupportedOperationException if no default mapped value
4533	>	* for additions was provided
4534	>	*/
4535	>	public boolean addAll(Collection<? extends K> c) {
4536	>	boolean added = false;
4537	>	V v;
4538	>	if ((v = value) == null)
4539	>	throw new UnsupportedOperationException();
4540	>	for (K e : c) {
4541	>	if (map.putVal(e, v, true) == null)
4542	>	added = true;
4543	>	}
4544	>	return added;
4545	>	}
4546	>
4547	>	public int hashCode() {
4548	>	int h = 0;
4549	>	for (K e : this)
4550	>	h += e.hashCode();
4551	>	return h;
4552	>	}
4553	>
4554	>	public boolean equals(Object o) {
4555	>	Set<?> c;
4556	>	return ((o instanceof Set) &&
4557	>	((c = (Set<?>)o) == this ||
4558	>	(containsAll(c) && c.containsAll(this))));
4559	>	}
4560	>
4561	>	public Spliterator<K> spliterator() {
4562	>	Node<K,V>[] t;
4563	>	ConcurrentHashMap<K,V> m = map;
4564	>	long n = m.sumCount();
4565	>	int f = (t = m.table) == null ? 0 : t.length;
4566	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4567	>	}
4568	>
4569	>	public void forEach(Consumer<? super K> action) {
4570	>	if (action == null) throw new NullPointerException();
4571	>	Node<K,V>[] t;
4572	>	if ((t = map.table) != null) {
4573	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4574	>	for (Node<K,V> p; (p = it.advance()) != null; )
4575	>	action.accept(p.key);
4576	>	}
4577		}
4578		}
4579
4580	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4581	<	public Iterator<Map.Entry<K,V>> iterator() {
4582	<	return new EntryIterator();
4580	>	/**
4581	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4582	>	* values, in which additions are disabled. This class cannot be
4583	>	* directly instantiated. See {@link #values()}.
4584	>	*/
4585	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4586	>	implements Collection<V>, java.io.Serializable {
4587	>	private static final long serialVersionUID = 2249069246763182397L;
4588	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4589	>	public final boolean contains(Object o) {
4590	>	return map.containsValue(o);
4591	>	}
4592	>
4593	>	public final boolean remove(Object o) {
4594	>	if (o != null) {
4595	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4596	>	if (o.equals(it.next())) {
4597	>	it.remove();
4598	>	return true;
4599	>	}
4600	>	}
4601	>	}
4602	>	return false;
4603	>	}
4604	>
4605	>	public final Iterator<V> iterator() {
4606	>	ConcurrentHashMap<K,V> m = map;
4607	>	Node<K,V>[] t;
4608	>	int f = (t = m.table) == null ? 0 : t.length;
4609	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4610	>	}
4611	>
4612	>	public final boolean add(V e) {
4613	>	throw new UnsupportedOperationException();
4614	>	}
4615	>	public final boolean addAll(Collection<? extends V> c) {
4616	>	throw new UnsupportedOperationException();
4617	>	}
4618	>
4619	>	public Spliterator<V> spliterator() {
4620	>	Node<K,V>[] t;
4621	>	ConcurrentHashMap<K,V> m = map;
4622	>	long n = m.sumCount();
4623	>	int f = (t = m.table) == null ? 0 : t.length;
4624	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4625	>	}
4626	>
4627	>	public void forEach(Consumer<? super V> action) {
4628	>	if (action == null) throw new NullPointerException();
4629	>	Node<K,V>[] t;
4630	>	if ((t = map.table) != null) {
4631	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4632	>	for (Node<K,V> p; (p = it.advance()) != null; )
4633	>	action.accept(p.val);
4634	>	}
4635		}
4636	+	}
4637	+
4638	+	/**
4639	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4640	+	* entries.  This class cannot be directly instantiated. See
4641	+	* {@link #entrySet()}.
4642	+	*/
4643	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4644	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4645	+	private static final long serialVersionUID = 2249069246763182397L;
4646	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4647	+
4648		public boolean contains(Object o) {
4649	<	if (!(o instanceof Map.Entry))
4650	<	return false;
4651	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4652	<	V v = ConcurrentHashMap.this.get(e.getKey());
4653	<	return v != null && v.equals(e.getValue());
4649	>	Object k, v, r; Map.Entry<?,?> e;
4650	>	return ((o instanceof Map.Entry) &&
4651	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4652	>	(r = map.get(k)) != null &&
4653	>	(v = e.getValue()) != null &&
4654	>	(v == r || v.equals(r)));
4655		}
4656	+
4657		public boolean remove(Object o) {
4658	<	if (!(o instanceof Map.Entry))
4659	<	return false;
4660	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4661	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4658	>	Object k, v; Map.Entry<?,?> e;
4659	>	return ((o instanceof Map.Entry) &&
4660	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4661	>	(v = e.getValue()) != null &&
4662	>	map.remove(k, v));
4663		}
4664	<	public int size() {
4665	<	return ConcurrentHashMap.this.size();
4664	>
4665	>	/**
4666	>	* @return an iterator over the entries of the backing map
4667	>	*/
4668	>	public Iterator<Map.Entry<K,V>> iterator() {
4669	>	ConcurrentHashMap<K,V> m = map;
4670	>	Node<K,V>[] t;
4671	>	int f = (t = m.table) == null ? 0 : t.length;
4672	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4673	>	}
4674	>
4675	>	public boolean add(Entry<K,V> e) {
4676	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4677	>	}
4678	>
4679	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4680	>	boolean added = false;
4681	>	for (Entry<K,V> e : c) {
4682	>	if (add(e))
4683	>	added = true;
4684	>	}
4685	>	return added;
4686	>	}
4687	>
4688	>	public final int hashCode() {
4689	>	int h = 0;
4690	>	Node<K,V>[] t;
4691	>	if ((t = map.table) != null) {
4692	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4693	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4694	>	h += p.hashCode();
4695	>	}
4696	>	}
4697	>	return h;
4698		}
4699	<	public void clear() {
4700	<	ConcurrentHashMap.this.clear();
4699	>
4700	>	public final boolean equals(Object o) {
4701	>	Set<?> c;
4702	>	return ((o instanceof Set) &&
4703	>	((c = (Set<?>)o) == this ||
4704	>	(containsAll(c) && c.containsAll(this))));
4705	>	}
4706	>
4707	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4708	>	Node<K,V>[] t;
4709	>	ConcurrentHashMap<K,V> m = map;
4710	>	long n = m.sumCount();
4711	>	int f = (t = m.table) == null ? 0 : t.length;
4712	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4713	>	}
4714	>
4715	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4716	>	if (action == null) throw new NullPointerException();
4717	>	Node<K,V>[] t;
4718	>	if ((t = map.table) != null) {
4719	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4720	>	for (Node<K,V> p; (p = it.advance()) != null; )
4721	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4722	>	}
4723		}
4724	+
4725		}
4726
4727	<	/* ---------------- Serialization Support -------------- */
4727	>	// -------------------------------------------------------
4728
4729		/**
4730	<	* Save the state of the <tt>ConcurrentHashMap</tt> instance to a
4731	<	* stream (i.e., serialize it).
1229	<	* @param s the stream
1230	<	* @serialData
1231	<	* the key (Object) and value (Object)
1232	<	* for each key-value mapping, followed by a null pair.
1233	<	* The key-value mappings are emitted in no particular order.
4730	>	* Base class for bulk tasks. Repeats some fields and code from
4731	>	* class Traverser, because we need to subclass CountedCompleter.
4732		*/
4733	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
4734	<	s.defaultWriteObject();
4733	>	@SuppressWarnings("serial")
4734	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4735	>	Node<K,V>[] tab;        // same as Traverser
4736	>	Node<K,V> next;
4737	>	TableStack<K,V> stack, spare;
4738	>	int index;
4739	>	int baseIndex;
4740	>	int baseLimit;
4741	>	final int baseSize;
4742	>	int batch;              // split control
4743	>
4744	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4745	>	super(par);
4746	>	this.batch = b;
4747	>	this.index = this.baseIndex = i;
4748	>	if ((this.tab = t) == null)
4749	>	this.baseSize = this.baseLimit = 0;
4750	>	else if (par == null)
4751	>	this.baseSize = this.baseLimit = t.length;
4752	>	else {
4753	>	this.baseLimit = f;
4754	>	this.baseSize = par.baseSize;
4755	>	}
4756	>	}
4757
4758	<	for (int k = 0; k < segments.length; ++k) {
4759	<	Segment<K,V> seg = segments[k];
4760	<	seg.lock();
4761	<	try {
4762	<	HashEntry<K,V>[] tab = seg.table;
4763	<	for (int i = 0; i < tab.length; ++i) {
4764	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
4765	<	s.writeObject(e.key);
4766	<	s.writeObject(e.value);
4758	>	/**
4759	>	* Same as Traverser version
4760	>	*/
4761	>	final Node<K,V> advance() {
4762	>	Node<K,V> e;
4763	>	if ((e = next) != null)
4764	>	e = e.next;
4765	>	for (;;) {
4766	>	Node<K,V>[] t; int i, n;
4767	>	if (e != null)
4768	>	return next = e;
4769	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4770	>	(n = t.length) <= (i = index) || i < 0)
4771	>	return next = null;
4772	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4773	>	if (e instanceof ForwardingNode) {
4774	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4775	>	e = null;
4776	>	pushState(t, i, n);
4777	>	continue;
4778		}
4779	+	else if (e instanceof TreeBin)
4780	+	e = ((TreeBin<K,V>)e).first;
4781	+	else
4782	+	e = null;
4783		}
4784	<	} finally {
4785	<	seg.unlock();
4784	>	if (stack != null)
4785	>	recoverState(n);
4786	>	else if ((index = i + baseSize) >= n)
4787	>	index = ++baseIndex;
4788		}
4789		}
4790	<	s.writeObject(null);
4791	<	s.writeObject(null);
4790	>
4791	>	private void pushState(Node<K,V>[] t, int i, int n) {
4792	>	TableStack<K,V> s = spare;
4793	>	if (s != null)
4794	>	spare = s.next;
4795	>	else
4796	>	s = new TableStack<K,V>();
4797	>	s.tab = t;
4798	>	s.length = n;
4799	>	s.index = i;
4800	>	s.next = stack;
4801	>	stack = s;
4802	>	}
4803	>
4804	>	private void recoverState(int n) {
4805	>	TableStack<K,V> s; int len;
4806	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4807	>	n = len;
4808	>	index = s.index;
4809	>	tab = s.tab;
4810	>	s.tab = null;
4811	>	TableStack<K,V> next = s.next;
4812	>	s.next = spare; // save for reuse
4813	>	stack = next;
4814	>	spare = s;
4815	>	}
4816	>	if (s == null && (index += baseSize) >= n)
4817	>	index = ++baseIndex;
4818	>	}
4819		}
4820
4821	<	/**
4822	<	* Reconstitute the <tt>ConcurrentHashMap</tt> instance from a
4823	<	* stream (i.e., deserialize it).
4824	<	* @param s the stream
4825	<	*/
4826	<	private void readObject(java.io.ObjectInputStream s)
4827	<	throws IOException, ClassNotFoundException  {
4828	<	s.defaultReadObject();
4821	>	/*
4822	>	* Task classes. Coded in a regular but ugly format/style to
4823	>	* simplify checks that each variant differs in the right way from
4824	>	* others. The null screenings exist because compilers cannot tell
4825	>	* that we've already null-checked task arguments, so we force
4826	>	* simplest hoisted bypass to help avoid convoluted traps.
4827	>	*/
4828	>	@SuppressWarnings("serial")
4829	>	static final class ForEachKeyTask<K,V>
4830	>	extends BulkTask<K,V,Void> {
4831	>	final Consumer<? super K> action;
4832	>	ForEachKeyTask
4833	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4834	>	Consumer<? super K> action) {
4835	>	super(p, b, i, f, t);
4836	>	this.action = action;
4837	>	}
4838	>	public final void compute() {
4839	>	final Consumer<? super K> action;
4840	>	if ((action = this.action) != null) {
4841	>	for (int i = baseIndex, f, h; batch > 0 &&
4842	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4843	>	addToPendingCount(1);
4844	>	new ForEachKeyTask<K,V>
4845	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4846	>	action).fork();
4847	>	}
4848	>	for (Node<K,V> p; (p = advance()) != null;)
4849	>	action.accept(p.key);
4850	>	propagateCompletion();
4851	>	}
4852	>	}
4853	>	}
4854
4855	<	// Initialize each segment to be minimally sized, and let grow.
4856	<	for (int i = 0; i < segments.length; ++i) {
4857	<	segments[i].setTable(new HashEntry[1]);
4855	>	@SuppressWarnings("serial")
4856	>	static final class ForEachValueTask<K,V>
4857	>	extends BulkTask<K,V,Void> {
4858	>	final Consumer<? super V> action;
4859	>	ForEachValueTask
4860	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4861	>	Consumer<? super V> action) {
4862	>	super(p, b, i, f, t);
4863	>	this.action = action;
4864	>	}
4865	>	public final void compute() {
4866	>	final Consumer<? super V> action;
4867	>	if ((action = this.action) != null) {
4868	>	for (int i = baseIndex, f, h; batch > 0 &&
4869	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4870	>	addToPendingCount(1);
4871	>	new ForEachValueTask<K,V>
4872	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4873	>	action).fork();
4874	>	}
4875	>	for (Node<K,V> p; (p = advance()) != null;)
4876	>	action.accept(p.val);
4877	>	propagateCompletion();
4878	>	}
4879		}
4880	+	}
4881
4882	<	// Read the keys and values, and put the mappings in the table
4883	<	for (;;) {
4884	<	K key = (K) s.readObject();
4885	<	V value = (V) s.readObject();
4886	<	if (key == null)
4887	<	break;
4888	<	put(key, value);
4882	>	@SuppressWarnings("serial")
4883	>	static final class ForEachEntryTask<K,V>
4884	>	extends BulkTask<K,V,Void> {
4885	>	final Consumer<? super Entry<K,V>> action;
4886	>	ForEachEntryTask
4887	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4888	>	Consumer<? super Entry<K,V>> action) {
4889	>	super(p, b, i, f, t);
4890	>	this.action = action;
4891	>	}
4892	>	public final void compute() {
4893	>	final Consumer<? super Entry<K,V>> action;
4894	>	if ((action = this.action) != null) {
4895	>	for (int i = baseIndex, f, h; batch > 0 &&
4896	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4897	>	addToPendingCount(1);
4898	>	new ForEachEntryTask<K,V>
4899	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4900	>	action).fork();
4901	>	}
4902	>	for (Node<K,V> p; (p = advance()) != null; )
4903	>	action.accept(p);
4904	>	propagateCompletion();
4905	>	}
4906	>	}
4907	>	}
4908	>
4909	>	@SuppressWarnings("serial")
4910	>	static final class ForEachMappingTask<K,V>
4911	>	extends BulkTask<K,V,Void> {
4912	>	final BiConsumer<? super K, ? super V> action;
4913	>	ForEachMappingTask
4914	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4915	>	BiConsumer<? super K,? super V> action) {
4916	>	super(p, b, i, f, t);
4917	>	this.action = action;
4918	>	}
4919	>	public final void compute() {
4920	>	final BiConsumer<? super K, ? super V> action;
4921	>	if ((action = this.action) != null) {
4922	>	for (int i = baseIndex, f, h; batch > 0 &&
4923	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4924	>	addToPendingCount(1);
4925	>	new ForEachMappingTask<K,V>
4926	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4927	>	action).fork();
4928	>	}
4929	>	for (Node<K,V> p; (p = advance()) != null; )
4930	>	action.accept(p.key, p.val);
4931	>	propagateCompletion();
4932	>	}
4933	>	}
4934	>	}
4935	>
4936	>	@SuppressWarnings("serial")
4937	>	static final class ForEachTransformedKeyTask<K,V,U>
4938	>	extends BulkTask<K,V,Void> {
4939	>	final Function<? super K, ? extends U> transformer;
4940	>	final Consumer<? super U> action;
4941	>	ForEachTransformedKeyTask
4942	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4943	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4944	>	super(p, b, i, f, t);
4945	>	this.transformer = transformer; this.action = action;
4946	>	}
4947	>	public final void compute() {
4948	>	final Function<? super K, ? extends U> transformer;
4949	>	final Consumer<? super U> action;
4950	>	if ((transformer = this.transformer) != null &&
4951	>	(action = this.action) != null) {
4952	>	for (int i = baseIndex, f, h; batch > 0 &&
4953	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4954	>	addToPendingCount(1);
4955	>	new ForEachTransformedKeyTask<K,V,U>
4956	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4957	>	transformer, action).fork();
4958	>	}
4959	>	for (Node<K,V> p; (p = advance()) != null; ) {
4960	>	U u;
4961	>	if ((u = transformer.apply(p.key)) != null)
4962	>	action.accept(u);
4963	>	}
4964	>	propagateCompletion();
4965	>	}
4966	>	}
4967	>	}
4968	>
4969	>	@SuppressWarnings("serial")
4970	>	static final class ForEachTransformedValueTask<K,V,U>
4971	>	extends BulkTask<K,V,Void> {
4972	>	final Function<? super V, ? extends U> transformer;
4973	>	final Consumer<? super U> action;
4974	>	ForEachTransformedValueTask
4975	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4976	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
4977	>	super(p, b, i, f, t);
4978	>	this.transformer = transformer; this.action = action;
4979	>	}
4980	>	public final void compute() {
4981	>	final Function<? super V, ? extends U> transformer;
4982	>	final Consumer<? super U> action;
4983	>	if ((transformer = this.transformer) != null &&
4984	>	(action = this.action) != null) {
4985	>	for (int i = baseIndex, f, h; batch > 0 &&
4986	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4987	>	addToPendingCount(1);
4988	>	new ForEachTransformedValueTask<K,V,U>
4989	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4990	>	transformer, action).fork();
4991	>	}
4992	>	for (Node<K,V> p; (p = advance()) != null; ) {
4993	>	U u;
4994	>	if ((u = transformer.apply(p.val)) != null)
4995	>	action.accept(u);
4996	>	}
4997	>	propagateCompletion();
4998	>	}
4999	>	}
5000	>	}
5001	>
5002	>	@SuppressWarnings("serial")
5003	>	static final class ForEachTransformedEntryTask<K,V,U>
5004	>	extends BulkTask<K,V,Void> {
5005	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5006	>	final Consumer<? super U> action;
5007	>	ForEachTransformedEntryTask
5008	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5009	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5010	>	super(p, b, i, f, t);
5011	>	this.transformer = transformer; this.action = action;
5012	>	}
5013	>	public final void compute() {
5014	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5015	>	final Consumer<? super U> action;
5016	>	if ((transformer = this.transformer) != null &&
5017	>	(action = this.action) != null) {
5018	>	for (int i = baseIndex, f, h; batch > 0 &&
5019	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5020	>	addToPendingCount(1);
5021	>	new ForEachTransformedEntryTask<K,V,U>
5022	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5023	>	transformer, action).fork();
5024	>	}
5025	>	for (Node<K,V> p; (p = advance()) != null; ) {
5026	>	U u;
5027	>	if ((u = transformer.apply(p)) != null)
5028	>	action.accept(u);
5029	>	}
5030	>	propagateCompletion();
5031	>	}
5032	>	}
5033	>	}
5034	>
5035	>	@SuppressWarnings("serial")
5036	>	static final class ForEachTransformedMappingTask<K,V,U>
5037	>	extends BulkTask<K,V,Void> {
5038	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5039	>	final Consumer<? super U> action;
5040	>	ForEachTransformedMappingTask
5041	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5042	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5043	>	Consumer<? super U> action) {
5044	>	super(p, b, i, f, t);
5045	>	this.transformer = transformer; this.action = action;
5046	>	}
5047	>	public final void compute() {
5048	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5049	>	final Consumer<? super U> action;
5050	>	if ((transformer = this.transformer) != null &&
5051	>	(action = this.action) != null) {
5052	>	for (int i = baseIndex, f, h; batch > 0 &&
5053	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5054	>	addToPendingCount(1);
5055	>	new ForEachTransformedMappingTask<K,V,U>
5056	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5057	>	transformer, action).fork();
5058	>	}
5059	>	for (Node<K,V> p; (p = advance()) != null; ) {
5060	>	U u;
5061	>	if ((u = transformer.apply(p.key, p.val)) != null)
5062	>	action.accept(u);
5063	>	}
5064	>	propagateCompletion();
5065	>	}
5066	>	}
5067	>	}
5068	>
5069	>	@SuppressWarnings("serial")
5070	>	static final class SearchKeysTask<K,V,U>
5071	>	extends BulkTask<K,V,U> {
5072	>	final Function<? super K, ? extends U> searchFunction;
5073	>	final AtomicReference<U> result;
5074	>	SearchKeysTask
5075	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5076	>	Function<? super K, ? extends U> searchFunction,
5077	>	AtomicReference<U> result) {
5078	>	super(p, b, i, f, t);
5079	>	this.searchFunction = searchFunction; this.result = result;
5080	>	}
5081	>	public final U getRawResult() { return result.get(); }
5082	>	public final void compute() {
5083	>	final Function<? super K, ? extends U> searchFunction;
5084	>	final AtomicReference<U> result;
5085	>	if ((searchFunction = this.searchFunction) != null &&
5086	>	(result = this.result) != null) {
5087	>	for (int i = baseIndex, f, h; batch > 0 &&
5088	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5089	>	if (result.get() != null)
5090	>	return;
5091	>	addToPendingCount(1);
5092	>	new SearchKeysTask<K,V,U>
5093	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5094	>	searchFunction, result).fork();
5095	>	}
5096	>	while (result.get() == null) {
5097	>	U u;
5098	>	Node<K,V> p;
5099	>	if ((p = advance()) == null) {
5100	>	propagateCompletion();
5101	>	break;
5102	>	}
5103	>	if ((u = searchFunction.apply(p.key)) != null) {
5104	>	if (result.compareAndSet(null, u))
5105	>	quietlyCompleteRoot();
5106	>	break;
5107	>	}
5108	>	}
5109	>	}
5110	>	}
5111	>	}
5112	>
5113	>	@SuppressWarnings("serial")
5114	>	static final class SearchValuesTask<K,V,U>
5115	>	extends BulkTask<K,V,U> {
5116	>	final Function<? super V, ? extends U> searchFunction;
5117	>	final AtomicReference<U> result;
5118	>	SearchValuesTask
5119	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5120	>	Function<? super V, ? extends U> searchFunction,
5121	>	AtomicReference<U> result) {
5122	>	super(p, b, i, f, t);
5123	>	this.searchFunction = searchFunction; this.result = result;
5124	>	}
5125	>	public final U getRawResult() { return result.get(); }
5126	>	public final void compute() {
5127	>	final Function<? super V, ? extends U> searchFunction;
5128	>	final AtomicReference<U> result;
5129	>	if ((searchFunction = this.searchFunction) != null &&
5130	>	(result = this.result) != null) {
5131	>	for (int i = baseIndex, f, h; batch > 0 &&
5132	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5133	>	if (result.get() != null)
5134	>	return;
5135	>	addToPendingCount(1);
5136	>	new SearchValuesTask<K,V,U>
5137	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5138	>	searchFunction, result).fork();
5139	>	}
5140	>	while (result.get() == null) {
5141	>	U u;
5142	>	Node<K,V> p;
5143	>	if ((p = advance()) == null) {
5144	>	propagateCompletion();
5145	>	break;
5146	>	}
5147	>	if ((u = searchFunction.apply(p.val)) != null) {
5148	>	if (result.compareAndSet(null, u))
5149	>	quietlyCompleteRoot();
5150	>	break;
5151	>	}
5152	>	}
5153	>	}
5154	>	}
5155	>	}
5156	>
5157	>	@SuppressWarnings("serial")
5158	>	static final class SearchEntriesTask<K,V,U>
5159	>	extends BulkTask<K,V,U> {
5160	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5161	>	final AtomicReference<U> result;
5162	>	SearchEntriesTask
5163	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5164	>	Function<Entry<K,V>, ? extends U> searchFunction,
5165	>	AtomicReference<U> result) {
5166	>	super(p, b, i, f, t);
5167	>	this.searchFunction = searchFunction; this.result = result;
5168	>	}
5169	>	public final U getRawResult() { return result.get(); }
5170	>	public final void compute() {
5171	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5172	>	final AtomicReference<U> result;
5173	>	if ((searchFunction = this.searchFunction) != null &&
5174	>	(result = this.result) != null) {
5175	>	for (int i = baseIndex, f, h; batch > 0 &&
5176	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5177	>	if (result.get() != null)
5178	>	return;
5179	>	addToPendingCount(1);
5180	>	new SearchEntriesTask<K,V,U>
5181	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5182	>	searchFunction, result).fork();
5183	>	}
5184	>	while (result.get() == null) {
5185	>	U u;
5186	>	Node<K,V> p;
5187	>	if ((p = advance()) == null) {
5188	>	propagateCompletion();
5189	>	break;
5190	>	}
5191	>	if ((u = searchFunction.apply(p)) != null) {
5192	>	if (result.compareAndSet(null, u))
5193	>	quietlyCompleteRoot();
5194	>	return;
5195	>	}
5196	>	}
5197	>	}
5198	>	}
5199	>	}
5200	>
5201	>	@SuppressWarnings("serial")
5202	>	static final class SearchMappingsTask<K,V,U>
5203	>	extends BulkTask<K,V,U> {
5204	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5205	>	final AtomicReference<U> result;
5206	>	SearchMappingsTask
5207	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5208	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5209	>	AtomicReference<U> result) {
5210	>	super(p, b, i, f, t);
5211	>	this.searchFunction = searchFunction; this.result = result;
5212	>	}
5213	>	public final U getRawResult() { return result.get(); }
5214	>	public final void compute() {
5215	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5216	>	final AtomicReference<U> result;
5217	>	if ((searchFunction = this.searchFunction) != null &&
5218	>	(result = this.result) != null) {
5219	>	for (int i = baseIndex, f, h; batch > 0 &&
5220	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5221	>	if (result.get() != null)
5222	>	return;
5223	>	addToPendingCount(1);
5224	>	new SearchMappingsTask<K,V,U>
5225	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5226	>	searchFunction, result).fork();
5227	>	}
5228	>	while (result.get() == null) {
5229	>	U u;
5230	>	Node<K,V> p;
5231	>	if ((p = advance()) == null) {
5232	>	propagateCompletion();
5233	>	break;
5234	>	}
5235	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5236	>	if (result.compareAndSet(null, u))
5237	>	quietlyCompleteRoot();
5238	>	break;
5239	>	}
5240	>	}
5241	>	}
5242	>	}
5243	>	}
5244	>
5245	>	@SuppressWarnings("serial")
5246	>	static final class ReduceKeysTask<K,V>
5247	>	extends BulkTask<K,V,K> {
5248	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5249	>	K result;
5250	>	ReduceKeysTask<K,V> rights, nextRight;
5251	>	ReduceKeysTask
5252	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5253	>	ReduceKeysTask<K,V> nextRight,
5254	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5255	>	super(p, b, i, f, t); this.nextRight = nextRight;
5256	>	this.reducer = reducer;
5257	>	}
5258	>	public final K getRawResult() { return result; }
5259	>	public final void compute() {
5260	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5261	>	if ((reducer = this.reducer) != null) {
5262	>	for (int i = baseIndex, f, h; batch > 0 &&
5263	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5264	>	addToPendingCount(1);
5265	>	(rights = new ReduceKeysTask<K,V>
5266	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5267	>	rights, reducer)).fork();
5268	>	}
5269	>	K r = null;
5270	>	for (Node<K,V> p; (p = advance()) != null; ) {
5271	>	K u = p.key;
5272	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5273	>	}
5274	>	result = r;
5275	>	CountedCompleter<?> c;
5276	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5277	>	@SuppressWarnings("unchecked")
5278	>	ReduceKeysTask<K,V>
5279	>	t = (ReduceKeysTask<K,V>)c,
5280	>	s = t.rights;
5281	>	while (s != null) {
5282	>	K tr, sr;
5283	>	if ((sr = s.result) != null)
5284	>	t.result = (((tr = t.result) == null) ? sr :
5285	>	reducer.apply(tr, sr));
5286	>	s = t.rights = s.nextRight;
5287	>	}
5288	>	}
5289	>	}
5290	>	}
5291	>	}
5292	>
5293	>	@SuppressWarnings("serial")
5294	>	static final class ReduceValuesTask<K,V>
5295	>	extends BulkTask<K,V,V> {
5296	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5297	>	V result;
5298	>	ReduceValuesTask<K,V> rights, nextRight;
5299	>	ReduceValuesTask
5300	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5301	>	ReduceValuesTask<K,V> nextRight,
5302	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5303	>	super(p, b, i, f, t); this.nextRight = nextRight;
5304	>	this.reducer = reducer;
5305	>	}
5306	>	public final V getRawResult() { return result; }
5307	>	public final void compute() {
5308	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5309	>	if ((reducer = this.reducer) != null) {
5310	>	for (int i = baseIndex, f, h; batch > 0 &&
5311	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5312	>	addToPendingCount(1);
5313	>	(rights = new ReduceValuesTask<K,V>
5314	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5315	>	rights, reducer)).fork();
5316	>	}
5317	>	V r = null;
5318	>	for (Node<K,V> p; (p = advance()) != null; ) {
5319	>	V v = p.val;
5320	>	r = (r == null) ? v : reducer.apply(r, v);
5321	>	}
5322	>	result = r;
5323	>	CountedCompleter<?> c;
5324	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5325	>	@SuppressWarnings("unchecked")
5326	>	ReduceValuesTask<K,V>
5327	>	t = (ReduceValuesTask<K,V>)c,
5328	>	s = t.rights;
5329	>	while (s != null) {
5330	>	V tr, sr;
5331	>	if ((sr = s.result) != null)
5332	>	t.result = (((tr = t.result) == null) ? sr :
5333	>	reducer.apply(tr, sr));
5334	>	s = t.rights = s.nextRight;
5335	>	}
5336	>	}
5337	>	}
5338	>	}
5339	>	}
5340	>
5341	>	@SuppressWarnings("serial")
5342	>	static final class ReduceEntriesTask<K,V>
5343	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5344	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5345	>	Map.Entry<K,V> result;
5346	>	ReduceEntriesTask<K,V> rights, nextRight;
5347	>	ReduceEntriesTask
5348	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5349	>	ReduceEntriesTask<K,V> nextRight,
5350	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5351	>	super(p, b, i, f, t); this.nextRight = nextRight;
5352	>	this.reducer = reducer;
5353	>	}
5354	>	public final Map.Entry<K,V> getRawResult() { return result; }
5355	>	public final void compute() {
5356	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5357	>	if ((reducer = this.reducer) != null) {
5358	>	for (int i = baseIndex, f, h; batch > 0 &&
5359	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5360	>	addToPendingCount(1);
5361	>	(rights = new ReduceEntriesTask<K,V>
5362	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5363	>	rights, reducer)).fork();
5364	>	}
5365	>	Map.Entry<K,V> r = null;
5366	>	for (Node<K,V> p; (p = advance()) != null; )
5367	>	r = (r == null) ? p : reducer.apply(r, p);
5368	>	result = r;
5369	>	CountedCompleter<?> c;
5370	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5371	>	@SuppressWarnings("unchecked")
5372	>	ReduceEntriesTask<K,V>
5373	>	t = (ReduceEntriesTask<K,V>)c,
5374	>	s = t.rights;
5375	>	while (s != null) {
5376	>	Map.Entry<K,V> tr, sr;
5377	>	if ((sr = s.result) != null)
5378	>	t.result = (((tr = t.result) == null) ? sr :
5379	>	reducer.apply(tr, sr));
5380	>	s = t.rights = s.nextRight;
5381	>	}
5382	>	}
5383	>	}
5384	>	}
5385	>	}
5386	>
5387	>	@SuppressWarnings("serial")
5388	>	static final class MapReduceKeysTask<K,V,U>
5389	>	extends BulkTask<K,V,U> {
5390	>	final Function<? super K, ? extends U> transformer;
5391	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5392	>	U result;
5393	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5394	>	MapReduceKeysTask
5395	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5396	>	MapReduceKeysTask<K,V,U> nextRight,
5397	>	Function<? super K, ? extends U> transformer,
5398	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5399	>	super(p, b, i, f, t); this.nextRight = nextRight;
5400	>	this.transformer = transformer;
5401	>	this.reducer = reducer;
5402	>	}
5403	>	public final U getRawResult() { return result; }
5404	>	public final void compute() {
5405	>	final Function<? super K, ? extends U> transformer;
5406	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5407	>	if ((transformer = this.transformer) != null &&
5408	>	(reducer = this.reducer) != null) {
5409	>	for (int i = baseIndex, f, h; batch > 0 &&
5410	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5411	>	addToPendingCount(1);
5412	>	(rights = new MapReduceKeysTask<K,V,U>
5413	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5414	>	rights, transformer, reducer)).fork();
5415	>	}
5416	>	U r = null;
5417	>	for (Node<K,V> p; (p = advance()) != null; ) {
5418	>	U u;
5419	>	if ((u = transformer.apply(p.key)) != null)
5420	>	r = (r == null) ? u : reducer.apply(r, u);
5421	>	}
5422	>	result = r;
5423	>	CountedCompleter<?> c;
5424	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5425	>	@SuppressWarnings("unchecked")
5426	>	MapReduceKeysTask<K,V,U>
5427	>	t = (MapReduceKeysTask<K,V,U>)c,
5428	>	s = t.rights;
5429	>	while (s != null) {
5430	>	U tr, sr;
5431	>	if ((sr = s.result) != null)
5432	>	t.result = (((tr = t.result) == null) ? sr :
5433	>	reducer.apply(tr, sr));
5434	>	s = t.rights = s.nextRight;
5435	>	}
5436	>	}
5437	>	}
5438	>	}
5439	>	}
5440	>
5441	>	@SuppressWarnings("serial")
5442	>	static final class MapReduceValuesTask<K,V,U>
5443	>	extends BulkTask<K,V,U> {
5444	>	final Function<? super V, ? extends U> transformer;
5445	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5446	>	U result;
5447	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5448	>	MapReduceValuesTask
5449	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5450	>	MapReduceValuesTask<K,V,U> nextRight,
5451	>	Function<? super V, ? extends U> transformer,
5452	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5453	>	super(p, b, i, f, t); this.nextRight = nextRight;
5454	>	this.transformer = transformer;
5455	>	this.reducer = reducer;
5456	>	}
5457	>	public final U getRawResult() { return result; }
5458	>	public final void compute() {
5459	>	final Function<? super V, ? extends U> transformer;
5460	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5461	>	if ((transformer = this.transformer) != null &&
5462	>	(reducer = this.reducer) != null) {
5463	>	for (int i = baseIndex, f, h; batch > 0 &&
5464	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5465	>	addToPendingCount(1);
5466	>	(rights = new MapReduceValuesTask<K,V,U>
5467	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5468	>	rights, transformer, reducer)).fork();
5469	>	}
5470	>	U r = null;
5471	>	for (Node<K,V> p; (p = advance()) != null; ) {
5472	>	U u;
5473	>	if ((u = transformer.apply(p.val)) != null)
5474	>	r = (r == null) ? u : reducer.apply(r, u);
5475	>	}
5476	>	result = r;
5477	>	CountedCompleter<?> c;
5478	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5479	>	@SuppressWarnings("unchecked")
5480	>	MapReduceValuesTask<K,V,U>
5481	>	t = (MapReduceValuesTask<K,V,U>)c,
5482	>	s = t.rights;
5483	>	while (s != null) {
5484	>	U tr, sr;
5485	>	if ((sr = s.result) != null)
5486	>	t.result = (((tr = t.result) == null) ? sr :
5487	>	reducer.apply(tr, sr));
5488	>	s = t.rights = s.nextRight;
5489	>	}
5490	>	}
5491	>	}
5492	>	}
5493	>	}
5494	>
5495	>	@SuppressWarnings("serial")
5496	>	static final class MapReduceEntriesTask<K,V,U>
5497	>	extends BulkTask<K,V,U> {
5498	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5499	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5500	>	U result;
5501	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5502	>	MapReduceEntriesTask
5503	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5504	>	MapReduceEntriesTask<K,V,U> nextRight,
5505	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5506	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5507	>	super(p, b, i, f, t); this.nextRight = nextRight;
5508	>	this.transformer = transformer;
5509	>	this.reducer = reducer;
5510	>	}
5511	>	public final U getRawResult() { return result; }
5512	>	public final void compute() {
5513	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5514	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5515	>	if ((transformer = this.transformer) != null &&
5516	>	(reducer = this.reducer) != null) {
5517	>	for (int i = baseIndex, f, h; batch > 0 &&
5518	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5519	>	addToPendingCount(1);
5520	>	(rights = new MapReduceEntriesTask<K,V,U>
5521	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5522	>	rights, transformer, reducer)).fork();
5523	>	}
5524	>	U r = null;
5525	>	for (Node<K,V> p; (p = advance()) != null; ) {
5526	>	U u;
5527	>	if ((u = transformer.apply(p)) != null)
5528	>	r = (r == null) ? u : reducer.apply(r, u);
5529	>	}
5530	>	result = r;
5531	>	CountedCompleter<?> c;
5532	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5533	>	@SuppressWarnings("unchecked")
5534	>	MapReduceEntriesTask<K,V,U>
5535	>	t = (MapReduceEntriesTask<K,V,U>)c,
5536	>	s = t.rights;
5537	>	while (s != null) {
5538	>	U tr, sr;
5539	>	if ((sr = s.result) != null)
5540	>	t.result = (((tr = t.result) == null) ? sr :
5541	>	reducer.apply(tr, sr));
5542	>	s = t.rights = s.nextRight;
5543	>	}
5544	>	}
5545	>	}
5546	>	}
5547	>	}
5548	>
5549	>	@SuppressWarnings("serial")
5550	>	static final class MapReduceMappingsTask<K,V,U>
5551	>	extends BulkTask<K,V,U> {
5552	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5553	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5554	>	U result;
5555	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5556	>	MapReduceMappingsTask
5557	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5558	>	MapReduceMappingsTask<K,V,U> nextRight,
5559	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5560	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5561	>	super(p, b, i, f, t); this.nextRight = nextRight;
5562	>	this.transformer = transformer;
5563	>	this.reducer = reducer;
5564	>	}
5565	>	public final U getRawResult() { return result; }
5566	>	public final void compute() {
5567	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5568	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5569	>	if ((transformer = this.transformer) != null &&
5570	>	(reducer = this.reducer) != null) {
5571	>	for (int i = baseIndex, f, h; batch > 0 &&
5572	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5573	>	addToPendingCount(1);
5574	>	(rights = new MapReduceMappingsTask<K,V,U>
5575	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5576	>	rights, transformer, reducer)).fork();
5577	>	}
5578	>	U r = null;
5579	>	for (Node<K,V> p; (p = advance()) != null; ) {
5580	>	U u;
5581	>	if ((u = transformer.apply(p.key, p.val)) != null)
5582	>	r = (r == null) ? u : reducer.apply(r, u);
5583	>	}
5584	>	result = r;
5585	>	CountedCompleter<?> c;
5586	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5587	>	@SuppressWarnings("unchecked")
5588	>	MapReduceMappingsTask<K,V,U>
5589	>	t = (MapReduceMappingsTask<K,V,U>)c,
5590	>	s = t.rights;
5591	>	while (s != null) {
5592	>	U tr, sr;
5593	>	if ((sr = s.result) != null)
5594	>	t.result = (((tr = t.result) == null) ? sr :
5595	>	reducer.apply(tr, sr));
5596	>	s = t.rights = s.nextRight;
5597	>	}
5598	>	}
5599	>	}
5600	>	}
5601	>	}
5602	>
5603	>	@SuppressWarnings("serial")
5604	>	static final class MapReduceKeysToDoubleTask<K,V>
5605	>	extends BulkTask<K,V,Double> {
5606	>	final ToDoubleFunction<? super K> transformer;
5607	>	final DoubleBinaryOperator reducer;
5608	>	final double basis;
5609	>	double result;
5610	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5611	>	MapReduceKeysToDoubleTask
5612	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5613	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5614	>	ToDoubleFunction<? super K> transformer,
5615	>	double basis,
5616	>	DoubleBinaryOperator reducer) {
5617	>	super(p, b, i, f, t); this.nextRight = nextRight;
5618	>	this.transformer = transformer;
5619	>	this.basis = basis; this.reducer = reducer;
5620	>	}
5621	>	public final Double getRawResult() { return result; }
5622	>	public final void compute() {
5623	>	final ToDoubleFunction<? super K> transformer;
5624	>	final DoubleBinaryOperator reducer;
5625	>	if ((transformer = this.transformer) != null &&
5626	>	(reducer = this.reducer) != null) {
5627	>	double r = this.basis;
5628	>	for (int i = baseIndex, f, h; batch > 0 &&
5629	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5630	>	addToPendingCount(1);
5631	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5632	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5633	>	rights, transformer, r, reducer)).fork();
5634	>	}
5635	>	for (Node<K,V> p; (p = advance()) != null; )
5636	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5637	>	result = r;
5638	>	CountedCompleter<?> c;
5639	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5640	>	@SuppressWarnings("unchecked")
5641	>	MapReduceKeysToDoubleTask<K,V>
5642	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5643	>	s = t.rights;
5644	>	while (s != null) {
5645	>	t.result = reducer.applyAsDouble(t.result, s.result);
5646	>	s = t.rights = s.nextRight;
5647	>	}
5648	>	}
5649	>	}
5650	>	}
5651	>	}
5652	>
5653	>	@SuppressWarnings("serial")
5654	>	static final class MapReduceValuesToDoubleTask<K,V>
5655	>	extends BulkTask<K,V,Double> {
5656	>	final ToDoubleFunction<? super V> transformer;
5657	>	final DoubleBinaryOperator reducer;
5658	>	final double basis;
5659	>	double result;
5660	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5661	>	MapReduceValuesToDoubleTask
5662	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5663	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5664	>	ToDoubleFunction<? super V> transformer,
5665	>	double basis,
5666	>	DoubleBinaryOperator reducer) {
5667	>	super(p, b, i, f, t); this.nextRight = nextRight;
5668	>	this.transformer = transformer;
5669	>	this.basis = basis; this.reducer = reducer;
5670	>	}
5671	>	public final Double getRawResult() { return result; }
5672	>	public final void compute() {
5673	>	final ToDoubleFunction<? super V> transformer;
5674	>	final DoubleBinaryOperator reducer;
5675	>	if ((transformer = this.transformer) != null &&
5676	>	(reducer = this.reducer) != null) {
5677	>	double r = this.basis;
5678	>	for (int i = baseIndex, f, h; batch > 0 &&
5679	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5680	>	addToPendingCount(1);
5681	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5682	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5683	>	rights, transformer, r, reducer)).fork();
5684	>	}
5685	>	for (Node<K,V> p; (p = advance()) != null; )
5686	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5687	>	result = r;
5688	>	CountedCompleter<?> c;
5689	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5690	>	@SuppressWarnings("unchecked")
5691	>	MapReduceValuesToDoubleTask<K,V>
5692	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5693	>	s = t.rights;
5694	>	while (s != null) {
5695	>	t.result = reducer.applyAsDouble(t.result, s.result);
5696	>	s = t.rights = s.nextRight;
5697	>	}
5698	>	}
5699	>	}
5700	>	}
5701	>	}
5702	>
5703	>	@SuppressWarnings("serial")
5704	>	static final class MapReduceEntriesToDoubleTask<K,V>
5705	>	extends BulkTask<K,V,Double> {
5706	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5707	>	final DoubleBinaryOperator reducer;
5708	>	final double basis;
5709	>	double result;
5710	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5711	>	MapReduceEntriesToDoubleTask
5712	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5713	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5714	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5715	>	double basis,
5716	>	DoubleBinaryOperator reducer) {
5717	>	super(p, b, i, f, t); this.nextRight = nextRight;
5718	>	this.transformer = transformer;
5719	>	this.basis = basis; this.reducer = reducer;
5720	>	}
5721	>	public final Double getRawResult() { return result; }
5722	>	public final void compute() {
5723	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5724	>	final DoubleBinaryOperator reducer;
5725	>	if ((transformer = this.transformer) != null &&
5726	>	(reducer = this.reducer) != null) {
5727	>	double r = this.basis;
5728	>	for (int i = baseIndex, f, h; batch > 0 &&
5729	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5730	>	addToPendingCount(1);
5731	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5732	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5733	>	rights, transformer, r, reducer)).fork();
5734	>	}
5735	>	for (Node<K,V> p; (p = advance()) != null; )
5736	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5737	>	result = r;
5738	>	CountedCompleter<?> c;
5739	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5740	>	@SuppressWarnings("unchecked")
5741	>	MapReduceEntriesToDoubleTask<K,V>
5742	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5743	>	s = t.rights;
5744	>	while (s != null) {
5745	>	t.result = reducer.applyAsDouble(t.result, s.result);
5746	>	s = t.rights = s.nextRight;
5747	>	}
5748	>	}
5749	>	}
5750	>	}
5751	>	}
5752	>
5753	>	@SuppressWarnings("serial")
5754	>	static final class MapReduceMappingsToDoubleTask<K,V>
5755	>	extends BulkTask<K,V,Double> {
5756	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5757	>	final DoubleBinaryOperator reducer;
5758	>	final double basis;
5759	>	double result;
5760	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5761	>	MapReduceMappingsToDoubleTask
5762	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5763	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5764	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5765	>	double basis,
5766	>	DoubleBinaryOperator reducer) {
5767	>	super(p, b, i, f, t); this.nextRight = nextRight;
5768	>	this.transformer = transformer;
5769	>	this.basis = basis; this.reducer = reducer;
5770	>	}
5771	>	public final Double getRawResult() { return result; }
5772	>	public final void compute() {
5773	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5774	>	final DoubleBinaryOperator reducer;
5775	>	if ((transformer = this.transformer) != null &&
5776	>	(reducer = this.reducer) != null) {
5777	>	double r = this.basis;
5778	>	for (int i = baseIndex, f, h; batch > 0 &&
5779	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5780	>	addToPendingCount(1);
5781	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5782	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5783	>	rights, transformer, r, reducer)).fork();
5784	>	}
5785	>	for (Node<K,V> p; (p = advance()) != null; )
5786	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5787	>	result = r;
5788	>	CountedCompleter<?> c;
5789	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5790	>	@SuppressWarnings("unchecked")
5791	>	MapReduceMappingsToDoubleTask<K,V>
5792	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5793	>	s = t.rights;
5794	>	while (s != null) {
5795	>	t.result = reducer.applyAsDouble(t.result, s.result);
5796	>	s = t.rights = s.nextRight;
5797	>	}
5798	>	}
5799	>	}
5800	>	}
5801	>	}
5802	>
5803	>	@SuppressWarnings("serial")
5804	>	static final class MapReduceKeysToLongTask<K,V>
5805	>	extends BulkTask<K,V,Long> {
5806	>	final ToLongFunction<? super K> transformer;
5807	>	final LongBinaryOperator reducer;
5808	>	final long basis;
5809	>	long result;
5810	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5811	>	MapReduceKeysToLongTask
5812	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5813	>	MapReduceKeysToLongTask<K,V> nextRight,
5814	>	ToLongFunction<? super K> transformer,
5815	>	long basis,
5816	>	LongBinaryOperator reducer) {
5817	>	super(p, b, i, f, t); this.nextRight = nextRight;
5818	>	this.transformer = transformer;
5819	>	this.basis = basis; this.reducer = reducer;
5820	>	}
5821	>	public final Long getRawResult() { return result; }
5822	>	public final void compute() {
5823	>	final ToLongFunction<? super K> transformer;
5824	>	final LongBinaryOperator reducer;
5825	>	if ((transformer = this.transformer) != null &&
5826	>	(reducer = this.reducer) != null) {
5827	>	long r = this.basis;
5828	>	for (int i = baseIndex, f, h; batch > 0 &&
5829	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5830	>	addToPendingCount(1);
5831	>	(rights = new MapReduceKeysToLongTask<K,V>
5832	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5833	>	rights, transformer, r, reducer)).fork();
5834	>	}
5835	>	for (Node<K,V> p; (p = advance()) != null; )
5836	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5837	>	result = r;
5838	>	CountedCompleter<?> c;
5839	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5840	>	@SuppressWarnings("unchecked")
5841	>	MapReduceKeysToLongTask<K,V>
5842	>	t = (MapReduceKeysToLongTask<K,V>)c,
5843	>	s = t.rights;
5844	>	while (s != null) {
5845	>	t.result = reducer.applyAsLong(t.result, s.result);
5846	>	s = t.rights = s.nextRight;
5847	>	}
5848	>	}
5849	>	}
5850	>	}
5851	>	}
5852	>
5853	>	@SuppressWarnings("serial")
5854	>	static final class MapReduceValuesToLongTask<K,V>
5855	>	extends BulkTask<K,V,Long> {
5856	>	final ToLongFunction<? super V> transformer;
5857	>	final LongBinaryOperator reducer;
5858	>	final long basis;
5859	>	long result;
5860	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5861	>	MapReduceValuesToLongTask
5862	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5863	>	MapReduceValuesToLongTask<K,V> nextRight,
5864	>	ToLongFunction<? super V> transformer,
5865	>	long basis,
5866	>	LongBinaryOperator reducer) {
5867	>	super(p, b, i, f, t); this.nextRight = nextRight;
5868	>	this.transformer = transformer;
5869	>	this.basis = basis; this.reducer = reducer;
5870	>	}
5871	>	public final Long getRawResult() { return result; }
5872	>	public final void compute() {
5873	>	final ToLongFunction<? super V> transformer;
5874	>	final LongBinaryOperator reducer;
5875	>	if ((transformer = this.transformer) != null &&
5876	>	(reducer = this.reducer) != null) {
5877	>	long r = this.basis;
5878	>	for (int i = baseIndex, f, h; batch > 0 &&
5879	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5880	>	addToPendingCount(1);
5881	>	(rights = new MapReduceValuesToLongTask<K,V>
5882	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5883	>	rights, transformer, r, reducer)).fork();
5884	>	}
5885	>	for (Node<K,V> p; (p = advance()) != null; )
5886	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5887	>	result = r;
5888	>	CountedCompleter<?> c;
5889	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5890	>	@SuppressWarnings("unchecked")
5891	>	MapReduceValuesToLongTask<K,V>
5892	>	t = (MapReduceValuesToLongTask<K,V>)c,
5893	>	s = t.rights;
5894	>	while (s != null) {
5895	>	t.result = reducer.applyAsLong(t.result, s.result);
5896	>	s = t.rights = s.nextRight;
5897	>	}
5898	>	}
5899	>	}
5900	>	}
5901	>	}
5902	>
5903	>	@SuppressWarnings("serial")
5904	>	static final class MapReduceEntriesToLongTask<K,V>
5905	>	extends BulkTask<K,V,Long> {
5906	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5907	>	final LongBinaryOperator reducer;
5908	>	final long basis;
5909	>	long result;
5910	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5911	>	MapReduceEntriesToLongTask
5912	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5913	>	MapReduceEntriesToLongTask<K,V> nextRight,
5914	>	ToLongFunction<Map.Entry<K,V>> transformer,
5915	>	long basis,
5916	>	LongBinaryOperator reducer) {
5917	>	super(p, b, i, f, t); this.nextRight = nextRight;
5918	>	this.transformer = transformer;
5919	>	this.basis = basis; this.reducer = reducer;
5920	>	}
5921	>	public final Long getRawResult() { return result; }
5922	>	public final void compute() {
5923	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5924	>	final LongBinaryOperator reducer;
5925	>	if ((transformer = this.transformer) != null &&
5926	>	(reducer = this.reducer) != null) {
5927	>	long r = this.basis;
5928	>	for (int i = baseIndex, f, h; batch > 0 &&
5929	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5930	>	addToPendingCount(1);
5931	>	(rights = new MapReduceEntriesToLongTask<K,V>
5932	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5933	>	rights, transformer, r, reducer)).fork();
5934	>	}
5935	>	for (Node<K,V> p; (p = advance()) != null; )
5936	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
5937	>	result = r;
5938	>	CountedCompleter<?> c;
5939	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5940	>	@SuppressWarnings("unchecked")
5941	>	MapReduceEntriesToLongTask<K,V>
5942	>	t = (MapReduceEntriesToLongTask<K,V>)c,
5943	>	s = t.rights;
5944	>	while (s != null) {
5945	>	t.result = reducer.applyAsLong(t.result, s.result);
5946	>	s = t.rights = s.nextRight;
5947	>	}
5948	>	}
5949	>	}
5950	>	}
5951	>	}
5952	>
5953	>	@SuppressWarnings("serial")
5954	>	static final class MapReduceMappingsToLongTask<K,V>
5955	>	extends BulkTask<K,V,Long> {
5956	>	final ToLongBiFunction<? super K, ? super V> transformer;
5957	>	final LongBinaryOperator reducer;
5958	>	final long basis;
5959	>	long result;
5960	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
5961	>	MapReduceMappingsToLongTask
5962	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5963	>	MapReduceMappingsToLongTask<K,V> nextRight,
5964	>	ToLongBiFunction<? super K, ? super V> transformer,
5965	>	long basis,
5966	>	LongBinaryOperator reducer) {
5967	>	super(p, b, i, f, t); this.nextRight = nextRight;
5968	>	this.transformer = transformer;
5969	>	this.basis = basis; this.reducer = reducer;
5970	>	}
5971	>	public final Long getRawResult() { return result; }
5972	>	public final void compute() {
5973	>	final ToLongBiFunction<? super K, ? super V> transformer;
5974	>	final LongBinaryOperator reducer;
5975	>	if ((transformer = this.transformer) != null &&
5976	>	(reducer = this.reducer) != null) {
5977	>	long r = this.basis;
5978	>	for (int i = baseIndex, f, h; batch > 0 &&
5979	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5980	>	addToPendingCount(1);
5981	>	(rights = new MapReduceMappingsToLongTask<K,V>
5982	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5983	>	rights, transformer, r, reducer)).fork();
5984	>	}
5985	>	for (Node<K,V> p; (p = advance()) != null; )
5986	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
5987	>	result = r;
5988	>	CountedCompleter<?> c;
5989	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5990	>	@SuppressWarnings("unchecked")
5991	>	MapReduceMappingsToLongTask<K,V>
5992	>	t = (MapReduceMappingsToLongTask<K,V>)c,
5993	>	s = t.rights;
5994	>	while (s != null) {
5995	>	t.result = reducer.applyAsLong(t.result, s.result);
5996	>	s = t.rights = s.nextRight;
5997	>	}
5998	>	}
5999	>	}
6000	>	}
6001	>	}
6002	>
6003	>	@SuppressWarnings("serial")
6004	>	static final class MapReduceKeysToIntTask<K,V>
6005	>	extends BulkTask<K,V,Integer> {
6006	>	final ToIntFunction<? super K> transformer;
6007	>	final IntBinaryOperator reducer;
6008	>	final int basis;
6009	>	int result;
6010	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6011	>	MapReduceKeysToIntTask
6012	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6013	>	MapReduceKeysToIntTask<K,V> nextRight,
6014	>	ToIntFunction<? super K> transformer,
6015	>	int basis,
6016	>	IntBinaryOperator reducer) {
6017	>	super(p, b, i, f, t); this.nextRight = nextRight;
6018	>	this.transformer = transformer;
6019	>	this.basis = basis; this.reducer = reducer;
6020	>	}
6021	>	public final Integer getRawResult() { return result; }
6022	>	public final void compute() {
6023	>	final ToIntFunction<? super K> transformer;
6024	>	final IntBinaryOperator reducer;
6025	>	if ((transformer = this.transformer) != null &&
6026	>	(reducer = this.reducer) != null) {
6027	>	int r = this.basis;
6028	>	for (int i = baseIndex, f, h; batch > 0 &&
6029	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6030	>	addToPendingCount(1);
6031	>	(rights = new MapReduceKeysToIntTask<K,V>
6032	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6033	>	rights, transformer, r, reducer)).fork();
6034	>	}
6035	>	for (Node<K,V> p; (p = advance()) != null; )
6036	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6037	>	result = r;
6038	>	CountedCompleter<?> c;
6039	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6040	>	@SuppressWarnings("unchecked")
6041	>	MapReduceKeysToIntTask<K,V>
6042	>	t = (MapReduceKeysToIntTask<K,V>)c,
6043	>	s = t.rights;
6044	>	while (s != null) {
6045	>	t.result = reducer.applyAsInt(t.result, s.result);
6046	>	s = t.rights = s.nextRight;
6047	>	}
6048	>	}
6049	>	}
6050	>	}
6051	>	}
6052	>
6053	>	@SuppressWarnings("serial")
6054	>	static final class MapReduceValuesToIntTask<K,V>
6055	>	extends BulkTask<K,V,Integer> {
6056	>	final ToIntFunction<? super V> transformer;
6057	>	final IntBinaryOperator reducer;
6058	>	final int basis;
6059	>	int result;
6060	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6061	>	MapReduceValuesToIntTask
6062	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6063	>	MapReduceValuesToIntTask<K,V> nextRight,
6064	>	ToIntFunction<? super V> transformer,
6065	>	int basis,
6066	>	IntBinaryOperator reducer) {
6067	>	super(p, b, i, f, t); this.nextRight = nextRight;
6068	>	this.transformer = transformer;
6069	>	this.basis = basis; this.reducer = reducer;
6070	>	}
6071	>	public final Integer getRawResult() { return result; }
6072	>	public final void compute() {
6073	>	final ToIntFunction<? super V> transformer;
6074	>	final IntBinaryOperator reducer;
6075	>	if ((transformer = this.transformer) != null &&
6076	>	(reducer = this.reducer) != null) {
6077	>	int r = this.basis;
6078	>	for (int i = baseIndex, f, h; batch > 0 &&
6079	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6080	>	addToPendingCount(1);
6081	>	(rights = new MapReduceValuesToIntTask<K,V>
6082	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6083	>	rights, transformer, r, reducer)).fork();
6084	>	}
6085	>	for (Node<K,V> p; (p = advance()) != null; )
6086	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6087	>	result = r;
6088	>	CountedCompleter<?> c;
6089	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6090	>	@SuppressWarnings("unchecked")
6091	>	MapReduceValuesToIntTask<K,V>
6092	>	t = (MapReduceValuesToIntTask<K,V>)c,
6093	>	s = t.rights;
6094	>	while (s != null) {
6095	>	t.result = reducer.applyAsInt(t.result, s.result);
6096	>	s = t.rights = s.nextRight;
6097	>	}
6098	>	}
6099	>	}
6100	>	}
6101	>	}
6102	>
6103	>	@SuppressWarnings("serial")
6104	>	static final class MapReduceEntriesToIntTask<K,V>
6105	>	extends BulkTask<K,V,Integer> {
6106	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6107	>	final IntBinaryOperator reducer;
6108	>	final int basis;
6109	>	int result;
6110	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6111	>	MapReduceEntriesToIntTask
6112	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6113	>	MapReduceEntriesToIntTask<K,V> nextRight,
6114	>	ToIntFunction<Map.Entry<K,V>> transformer,
6115	>	int basis,
6116	>	IntBinaryOperator reducer) {
6117	>	super(p, b, i, f, t); this.nextRight = nextRight;
6118	>	this.transformer = transformer;
6119	>	this.basis = basis; this.reducer = reducer;
6120	>	}
6121	>	public final Integer getRawResult() { return result; }
6122	>	public final void compute() {
6123	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6124	>	final IntBinaryOperator reducer;
6125	>	if ((transformer = this.transformer) != null &&
6126	>	(reducer = this.reducer) != null) {
6127	>	int r = this.basis;
6128	>	for (int i = baseIndex, f, h; batch > 0 &&
6129	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6130	>	addToPendingCount(1);
6131	>	(rights = new MapReduceEntriesToIntTask<K,V>
6132	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6133	>	rights, transformer, r, reducer)).fork();
6134	>	}
6135	>	for (Node<K,V> p; (p = advance()) != null; )
6136	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6137	>	result = r;
6138	>	CountedCompleter<?> c;
6139	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6140	>	@SuppressWarnings("unchecked")
6141	>	MapReduceEntriesToIntTask<K,V>
6142	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6143	>	s = t.rights;
6144	>	while (s != null) {
6145	>	t.result = reducer.applyAsInt(t.result, s.result);
6146	>	s = t.rights = s.nextRight;
6147	>	}
6148	>	}
6149	>	}
6150	>	}
6151	>	}
6152	>
6153	>	@SuppressWarnings("serial")
6154	>	static final class MapReduceMappingsToIntTask<K,V>
6155	>	extends BulkTask<K,V,Integer> {
6156	>	final ToIntBiFunction<? super K, ? super V> transformer;
6157	>	final IntBinaryOperator reducer;
6158	>	final int basis;
6159	>	int result;
6160	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6161	>	MapReduceMappingsToIntTask
6162	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6163	>	MapReduceMappingsToIntTask<K,V> nextRight,
6164	>	ToIntBiFunction<? super K, ? super V> transformer,
6165	>	int basis,
6166	>	IntBinaryOperator reducer) {
6167	>	super(p, b, i, f, t); this.nextRight = nextRight;
6168	>	this.transformer = transformer;
6169	>	this.basis = basis; this.reducer = reducer;
6170	>	}
6171	>	public final Integer getRawResult() { return result; }
6172	>	public final void compute() {
6173	>	final ToIntBiFunction<? super K, ? super V> transformer;
6174	>	final IntBinaryOperator reducer;
6175	>	if ((transformer = this.transformer) != null &&
6176	>	(reducer = this.reducer) != null) {
6177	>	int r = this.basis;
6178	>	for (int i = baseIndex, f, h; batch > 0 &&
6179	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6180	>	addToPendingCount(1);
6181	>	(rights = new MapReduceMappingsToIntTask<K,V>
6182	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6183	>	rights, transformer, r, reducer)).fork();
6184	>	}
6185	>	for (Node<K,V> p; (p = advance()) != null; )
6186	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6187	>	result = r;
6188	>	CountedCompleter<?> c;
6189	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6190	>	@SuppressWarnings("unchecked")
6191	>	MapReduceMappingsToIntTask<K,V>
6192	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6193	>	s = t.rights;
6194	>	while (s != null) {
6195	>	t.result = reducer.applyAsInt(t.result, s.result);
6196	>	s = t.rights = s.nextRight;
6197	>	}
6198	>	}
6199	>	}
6200	>	}
6201	>	}
6202	>
6203	>	// Unsafe mechanics
6204	>	private static final sun.misc.Unsafe U;
6205	>	private static final long SIZECTL;
6206	>	private static final long TRANSFERINDEX;
6207	>	private static final long BASECOUNT;
6208	>	private static final long CELLSBUSY;
6209	>	private static final long CELLVALUE;
6210	>	private static final long ABASE;
6211	>	private static final int ASHIFT;
6212	>
6213	>	static {
6214	>	try {
6215	>	U = sun.misc.Unsafe.getUnsafe();
6216	>	Class<?> k = ConcurrentHashMap.class;
6217	>	SIZECTL = U.objectFieldOffset
6218	>	(k.getDeclaredField("sizeCtl"));
6219	>	TRANSFERINDEX = U.objectFieldOffset
6220	>	(k.getDeclaredField("transferIndex"));
6221	>	BASECOUNT = U.objectFieldOffset
6222	>	(k.getDeclaredField("baseCount"));
6223	>	CELLSBUSY = U.objectFieldOffset
6224	>	(k.getDeclaredField("cellsBusy"));
6225	>	Class<?> ck = CounterCell.class;
6226	>	CELLVALUE = U.objectFieldOffset
6227	>	(ck.getDeclaredField("value"));
6228	>	Class<?> ak = Node[].class;
6229	>	ABASE = U.arrayBaseOffset(ak);
6230	>	int scale = U.arrayIndexScale(ak);
6231	>	if ((scale & (scale - 1)) != 0)
6232	>	throw new Error("data type scale not a power of two");
6233	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6234	>	} catch (Exception e) {
6235	>	throw new Error(e);
6236		}
6237		}
6238		}

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