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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.83 by jsr166, Mon Aug 22 03:42:10 2005 UTC vs.
Revision 1.252 by dl, Sun Dec 1 13:38:58 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}/../guide/collections/index.html">
230	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
231		* Java Collections Framework</a>.
232		*
233		* @since 1.5
#	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.  A generation stamp in field
355	>	* sizeCtl ensures that resizings do not overlap. Because we are
356	>	* using power-of-two expansion, the elements from each bin must
357	>	* either stay at same index, or move with a power of two
358	>	* offset. We eliminate unnecessary node creation by catching
359	>	* cases where old nodes can be reused because their next fields
360	>	* won't change.  On average, only about one-sixth of them need
361	>	* cloning when a table doubles. The nodes they replace will be
362	>	* garbage collectable as soon as they are no longer referenced by
363	>	* any reader thread that may be in the midst of concurrently
364	>	* traversing table.  Upon transfer, the old table bin contains
365	>	* only a special forwarding node (with hash field "MOVED") that
366	>	* contains the next table as its key. On encountering a
367	>	* forwarding node, access and update operations restart, using
368	>	* the new table.
369	>	*
370	>	* Each bin transfer requires its bin lock, which can stall
371	>	* waiting for locks while resizing. However, because other
372	>	* threads can join in and help resize rather than contend for
373	>	* locks, average aggregate waits become shorter as resizing
374	>	* progresses.  The transfer operation must also ensure that all
375	>	* accessible bins in both the old and new table are usable by any
376	>	* traversal.  This is arranged in part by proceeding from the
377	>	* last bin (table.length - 1) up towards the first.  Upon seeing
378	>	* a forwarding node, traversals (see class Traverser) arrange to
379	>	* move to the new table without revisiting nodes.  To ensure that
380	>	* no intervening nodes are skipped even when moved out of order,
381	>	* a stack (see class TableStack) is created on first encounter of
382	>	* a forwarding node during a traversal, to maintain its place if
383	>	* later processing the current table. The need for these
384	>	* save/restore mechanics is relatively rare, but when one
385	>	* forwarding node is encountered, typically many more will be.
386	>	* So Traversers use a simple caching scheme to avoid creating so
387	>	* many new TableStack nodes. (Thanks to Peter Levart for
388	>	* suggesting use of a stack here.)
389	>	*
390	>	* The traversal scheme also applies to partial traversals of
391	>	* ranges of bins (via an alternate Traverser constructor)
392	>	* to support partitioned aggregate operations.  Also, read-only
393	>	* operations give up if ever forwarded to a null table, which
394	>	* provides support for shutdown-style clearing, which is also not
395	>	* currently implemented.
396	>	*
397	>	* Lazy table initialization minimizes footprint until first use,
398	>	* and also avoids resizings when the first operation is from a
399	>	* putAll, constructor with map argument, or deserialization.
400	>	* These cases attempt to override the initial capacity settings,
401	>	* but harmlessly fail to take effect in cases of races.
402	>	*
403	>	* The element count is maintained using a specialization of
404	>	* LongAdder. We need to incorporate a specialization rather than
405	>	* just use a LongAdder in order to access implicit
406	>	* contention-sensing that leads to creation of multiple
407	>	* CounterCells.  The counter mechanics avoid contention on
408	>	* updates but can encounter cache thrashing if read too
409	>	* frequently during concurrent access. To avoid reading so often,
410	>	* resizing under contention is attempted only upon adding to a
411	>	* bin already holding two or more nodes. Under uniform hash
412	>	* distributions, the probability of this occurring at threshold
413	>	* is around 13%, meaning that only about 1 in 8 puts check
414	>	* threshold (and after resizing, many fewer do so).
415	>	*
416	>	* TreeBins use a special form of comparison for search and
417	>	* related operations (which is the main reason we cannot use
418	>	* existing collections such as TreeMaps). TreeBins contain
419	>	* Comparable elements, but may contain others, as well as
420	>	* elements that are Comparable but not necessarily Comparable for
421	>	* the same T, so we cannot invoke compareTo among them. To handle
422	>	* this, the tree is ordered primarily by hash value, then by
423	>	* Comparable.compareTo order if applicable.  On lookup at a node,
424	>	* if elements are not comparable or compare as 0 then both left
425	>	* and right children may need to be searched in the case of tied
426	>	* hash values. (This corresponds to the full list search that
427	>	* would be necessary if all elements were non-Comparable and had
428	>	* tied hashes.) On insertion, to keep a total ordering (or as
429	>	* close as is required here) across rebalancings, we compare
430	>	* classes and identityHashCodes as tie-breakers. The red-black
431	>	* balancing code is updated from pre-jdk-collections
432	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
433	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
434	>	* Algorithms" (CLR).
435	>	*
436	>	* TreeBins also require an additional locking mechanism.  While
437	>	* list traversal is always possible by readers even during
438	>	* updates, tree traversal is not, mainly because of tree-rotations
439	>	* that may change the root node and/or its linkages.  TreeBins
440	>	* include a simple read-write lock mechanism parasitic on the
441	>	* main bin-synchronization strategy: Structural adjustments
442	>	* associated with an insertion or removal are already bin-locked
443	>	* (and so cannot conflict with other writers) but must wait for
444	>	* ongoing readers to finish. Since there can be only one such
445	>	* waiter, we use a simple scheme using a single "waiter" field to
446	>	* block writers.  However, readers need never block.  If the root
447	>	* lock is held, they proceed along the slow traversal path (via
448	>	* next-pointers) until the lock becomes available or the list is
449	>	* exhausted, whichever comes first. These cases are not fast, but
450	>	* maximize aggregate expected throughput.
451	>	*
452	>	* Maintaining API and serialization compatibility with previous
453	>	* versions of this class introduces several oddities. Mainly: We
454	>	* leave untouched but unused constructor arguments refering to
455	>	* concurrencyLevel. We accept a loadFactor constructor argument,
456	>	* but apply it only to initial table capacity (which is the only
457	>	* time that we can guarantee to honor it.) We also declare an
458	>	* unused "Segment" class that is instantiated in minimal form
459	>	* only when serializing.
460	>	*
461	>	* Also, solely for compatibility with previous versions of this
462	>	* class, it extends AbstractMap, even though all of its methods
463	>	* are overridden, so it is just useless baggage.
464	>	*
465	>	* This file is organized to make things a little easier to follow
466	>	* while reading than they might otherwise: First the main static
467	>	* declarations and utilities, then fields, then main public
468	>	* methods (with a few factorings of multiple public methods into
469	>	* internal ones), then sizing methods, trees, traversers, and
470	>	* bulk operations.
471		*/
472
473		/* ---------------- Constants -------------- */
474
475		/**
476	<	* The default initial capacity for this table,
477	<	* used when not otherwise specified in a constructor.
476	>	* The largest possible table capacity.  This value must be
477	>	* exactly 1<<30 to stay within Java array allocation and indexing
478	>	* bounds for power of two table sizes, and is further required
479	>	* because the top two bits of 32bit hash fields are used for
480	>	* control purposes.
481		*/
482	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
482	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
483
484		/**
485	<	* The default load factor for this table, used when not
486	<	* otherwise specified in a constructor.
485	>	* The default initial table capacity.  Must be a power of 2
486	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
487		*/
488	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
488	>	private static final int DEFAULT_CAPACITY = 16;
489
490		/**
491	<	* The default concurrency level for this table, used when not
492	<	* otherwise specified in a constructor.
491	>	* The largest possible (non-power of two) array size.
492	>	* Needed by toArray and related methods.
493		*/
494	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
494	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
495
496		/**
497	<	* The maximum capacity, used if a higher value is implicitly
498	<	* 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.
497	>	* The default concurrency level for this table. Unused but
498	>	* defined for compatibility with previous versions of this class.
499		*/
500	<	static final int MAXIMUM_CAPACITY = 1 << 30;
500	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
501
502		/**
503	<	* The maximum number of segments to allow; used to bound
504	<	* constructor arguments.
503	>	* The load factor for this table. Overrides of this value in
504	>	* constructors affect only the initial table capacity.  The
505	>	* actual floating point value isn't normally used -- it is
506	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
507	>	* the associated resizing threshold.
508		*/
509	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
509	>	private static final float LOAD_FACTOR = 0.75f;
510
511		/**
512	<	* Number of unsynchronized retries in size and containsValue
513	<	* methods before resorting to locking. This is used to avoid
514	<	* unbounded retries if tables undergo continuous modification
515	<	* which would make it impossible to obtain an accurate result.
512	>	* The bin count threshold for using a tree rather than list for a
513	>	* bin.  Bins are converted to trees when adding an element to a
514	>	* bin with at least this many nodes. The value must be greater
515	>	* than 2, and should be at least 8 to mesh with assumptions in
516	>	* tree removal about conversion back to plain bins upon
517	>	* shrinkage.
518		*/
519	<	static final int RETRIES_BEFORE_LOCK = 2;
123	<
124	<	/* ---------------- Fields -------------- */
519	>	static final int TREEIFY_THRESHOLD = 8;
520
521		/**
522	<	* Mask value for indexing into segments. The upper bits of a
523	<	* key's hash code are used to choose the segment.
522	>	* The bin count threshold for untreeifying a (split) bin during a
523	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
524	>	* most 6 to mesh with shrinkage detection under removal.
525		*/
526	<	final int segmentMask;
526	>	static final int UNTREEIFY_THRESHOLD = 6;
527
528		/**
529	<	* Shift value for indexing within segments.
529	>	* The smallest table capacity for which bins may be treeified.
530	>	* (Otherwise the table is resized if too many nodes in a bin.)
531	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
532	>	* conflicts between resizing and treeification thresholds.
533		*/
534	<	final int segmentShift;
534	>	static final int MIN_TREEIFY_CAPACITY = 64;
535
536		/**
537	<	* The segments, each of which is a specialized hash table
537	>	* Minimum number of rebinnings per transfer step. Ranges are
538	>	* subdivided to allow multiple resizer threads.  This value
539	>	* serves as a lower bound to avoid resizers encountering
540	>	* excessive memory contention.  The value should be at least
541	>	* DEFAULT_CAPACITY.
542		*/
543	<	final Segment<K,V>[] segments;
543	>	private static final int MIN_TRANSFER_STRIDE = 16;
544
545	<	transient Set<K> keySet;
546	<	transient Set<Map.Entry<K,V>> entrySet;
547	<	transient Collection<V> values;
548	<
549	<	/* ---------------- Small Utilities -------------- */
545	>	/**
546	>	* The number of bits used for generation stamp in sizeCtl.
547	>	* Must be at least 6 for 32bit arrays.
548	>	*/
549	>	private static int RESIZE_STAMP_BITS = 16;
550
551		/**
552	<	* Returns a hash code for non-null Object x.
553	<	* Uses the same hash code spreader as most other java.util hash tables.
151	<	* @param x the object serving as a key
152	<	* @return the hash code
552	>	* The maximum number of threads that can help resize.
553	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
554		*/
555	<	static int hash(Object x) {
155	<	int h = x.hashCode();
156	<	h += ~(h << 9);
157	<	h ^=  (h >>> 14);
158	<	h +=  (h << 4);
159	<	h ^=  (h >>> 10);
160	<	return h;
161	<	}
555	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
556
557		/**
558	<	* Returns the segment that should be used for key with given hash
165	<	* @param hash the hash code for the key
166	<	* @return the segment
558	>	* The bit shift for recording size stamp in sizeCtl.
559		*/
560	<	final Segment<K,V> segmentFor(int hash) {
561	<	return segments[(hash >>> segmentShift) & segmentMask];
562	<	}
560	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
561	>
562	>	/*
563	>	* Encodings for Node hash fields. See above for explanation.
564	>	*/
565	>	static final int MOVED     = -1; // hash for forwarding nodes
566	>	static final int TREEBIN   = -2; // hash for roots of trees
567	>	static final int RESERVED  = -3; // hash for transient reservations
568	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
569	>
570	>	/** Number of CPUS, to place bounds on some sizings */
571	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
572	>
573	>	/** For serialization compatibility. */
574	>	private static final ObjectStreamField[] serialPersistentFields = {
575	>	new ObjectStreamField("segments", Segment[].class),
576	>	new ObjectStreamField("segmentMask", Integer.TYPE),
577	>	new ObjectStreamField("segmentShift", Integer.TYPE)
578	>	};
579
580	<	/* ---------------- Inner Classes -------------- */
580	>	/* ---------------- Nodes -------------- */
581
582		/**
583	<	* ConcurrentHashMap list entry. Note that this is never exported
584	<	* out as a user-visible Map.Entry.
585	<	*
586	<	* Because the value field is volatile, not final, it is legal wrt
587	<	* the Java Memory Model for an unsynchronized reader to see null
588	<	* instead of initial value when read via a data race.  Although a
181	<	* reordering leading to this is not likely to ever actually
182	<	* occur, the Segment.readValueUnderLock method is used as a
183	<	* backup in case a null (pre-initialized) value is ever seen in
184	<	* an unsynchronized access method.
583	>	* Key-value entry.  This class is never exported out as a
584	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
585	>	* MapEntry below), but can be used for read-only traversals used
586	>	* in bulk tasks.  Subclasses of Node with a negative hash field
587	>	* are special, and contain null keys and values (but are never
588	>	* exported).  Otherwise, keys and vals are never null.
589		*/
590	<	static final class HashEntry<K,V> {
187	<	final K key;
590	>	static class Node<K,V> implements Map.Entry<K,V> {
591		final int hash;
592	<	volatile V value;
593	<	final HashEntry<K,V> next;
592	>	final K key;
593	>	volatile V val;
594	>	volatile Node<K,V> next;
595
596	<	HashEntry(K key, int hash, HashEntry<K,V> next, V value) {
193	<	this.key = key;
596	>	Node(int hash, K key, V val, Node<K,V> next) {
597		this.hash = hash;
598	+	this.key = key;
599	+	this.val = val;
600		this.next = next;
196	–	this.value = value;
601		}
602
603	<	@SuppressWarnings("unchecked")
604	<	static final <K,V> HashEntry<K,V>[] newArray(int i) {
605	<	return new HashEntry[i];
606	<	}
603	>	public final K getKey()       { return key; }
604	>	public final V getValue()     { return val; }
605	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
606	>	public final String toString(){ return key + "=" + val; }
607	>	public final V setValue(V value) {
608	>	throw new UnsupportedOperationException();
609	>	}
610	>
611	>	public final boolean equals(Object o) {
612	>	Object k, v, u; Map.Entry<?,?> e;
613	>	return ((o instanceof Map.Entry) &&
614	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
615	>	(v = e.getValue()) != null &&
616	>	(k == key || k.equals(key)) &&
617	>	(v == (u = val) || v.equals(u)));
618	>	}
619	>
620	>	/**
621	>	* Virtualized support for map.get(); overridden in subclasses.
622	>	*/
623	>	Node<K,V> find(int h, Object k) {
624	>	Node<K,V> e = this;
625	>	if (k != null) {
626	>	do {
627	>	K ek;
628	>	if (e.hash == h &&
629	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
630	>	return e;
631	>	} while ((e = e.next) != null);
632	>	}
633	>	return null;
634	>	}
635		}
636
637	+	/* ---------------- Static utilities -------------- */
638	+
639		/**
640	<	* Segments are specialized versions of hash tables.  This
641	<	* subclasses from ReentrantLock opportunistically, just to
642	<	* simplify some locking and avoid separate construction.
640	>	* Spreads (XORs) higher bits of hash to lower and also forces top
641	>	* bit to 0. Because the table uses power-of-two masking, sets of
642	>	* hashes that vary only in bits above the current mask will
643	>	* always collide. (Among known examples are sets of Float keys
644	>	* holding consecutive whole numbers in small tables.)  So we
645	>	* apply a transform that spreads the impact of higher bits
646	>	* downward. There is a tradeoff between speed, utility, and
647	>	* quality of bit-spreading. Because many common sets of hashes
648	>	* are already reasonably distributed (so don't benefit from
649	>	* spreading), and because we use trees to handle large sets of
650	>	* collisions in bins, we just XOR some shifted bits in the
651	>	* cheapest possible way to reduce systematic lossage, as well as
652	>	* to incorporate impact of the highest bits that would otherwise
653	>	* never be used in index calculations because of table bounds.
654		*/
655	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
656	<	/*
657	<	* Segments maintain a table of entry lists that are ALWAYS
213	<	* kept in a consistent state, so can be read without locking.
214	<	* Next fields of nodes are immutable (final).  All list
215	<	* additions are performed at the front of each bin. This
216	<	* makes it easy to check changes, and also fast to traverse.
217	<	* When nodes would otherwise be changed, new nodes are
218	<	* created to replace them. This works well for hash tables
219	<	* since the bin lists tend to be short. (The average length
220	<	* is less than two for the default load factor threshold.)
221	<	*
222	<	* Read operations can thus proceed without locking, but rely
223	<	* on selected uses of volatiles to ensure that completed
224	<	* write operations performed by other threads are
225	<	* noticed. For most purposes, the "count" field, tracking the
226	<	* number of elements, serves as that volatile variable
227	<	* ensuring visibility.  This is convenient because this field
228	<	* needs to be read in many read operations anyway:
229	<	*
230	<	*   - All (unsynchronized) read operations must first read the
231	<	*     "count" field, and should not look at table entries if
232	<	*     it is 0.
233	<	*
234	<	*   - All (synchronized) write operations should write to
235	<	*     the "count" field after structurally changing any bin.
236	<	*     The operations must not take any action that could even
237	<	*     momentarily cause a concurrent read operation to see
238	<	*     inconsistent data. This is made easier by the nature of
239	<	*     the read operations in Map. For example, no operation
240	<	*     can reveal that the table has grown but the threshold
241	<	*     has not yet been updated, so there are no atomicity
242	<	*     requirements for this with respect to reads.
243	<	*
244	<	* As a guide, all critical volatile reads and writes to the
245	<	* count field are marked in code comments.
246	<	*/
655	>	static final int spread(int h) {
656	>	return (h ^ (h >>> 16)) & HASH_BITS;
657	>	}
658
659	<	private static final long serialVersionUID = 2249069246763182397L;
659	>	/**
660	>	* Returns a power of two table size for the given desired capacity.
661	>	* See Hackers Delight, sec 3.2
662	>	*/
663	>	private static final int tableSizeFor(int c) {
664	>	int n = c - 1;
665	>	n |= n >>> 1;
666	>	n |= n >>> 2;
667	>	n |= n >>> 4;
668	>	n |= n >>> 8;
669	>	n |= n >>> 16;
670	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
671	>	}
672
673	<	/**
674	<	* The number of elements in this segment's region.
675	<	*/
676	<	transient volatile int count;
673	>	/**
674	>	* Returns x's Class if it is of the form "class C implements
675	>	* Comparable<C>", else null.
676	>	*/
677	>	static Class<?> comparableClassFor(Object x) {
678	>	if (x instanceof Comparable) {
679	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
680	>	if ((c = x.getClass()) == String.class) // bypass checks
681	>	return c;
682	>	if ((ts = c.getGenericInterfaces()) != null) {
683	>	for (int i = 0; i < ts.length; ++i) {
684	>	if (((t = ts[i]) instanceof ParameterizedType) &&
685	>	((p = (ParameterizedType)t).getRawType() ==
686	>	Comparable.class) &&
687	>	(as = p.getActualTypeArguments()) != null &&
688	>	as.length == 1 && as[0] == c) // type arg is c
689	>	return c;
690	>	}
691	>	}
692	>	}
693	>	return null;
694	>	}
695
696	<	/**
697	<	* Number of updates that alter the size of the table. This is
698	<	* used during bulk-read methods to make sure they see a
699	<	* consistent snapshot: If modCounts change during a traversal
700	<	* of segments computing size or checking containsValue, then
701	<	* we might have an inconsistent view of state so (usually)
702	<	* must retry.
703	<	*/
704	<	transient int modCount;
696	>	/**
697	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
698	>	* class), else 0.
699	>	*/
700	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
701	>	static int compareComparables(Class<?> kc, Object k, Object x) {
702	>	return (x == null || x.getClass() != kc ? 0 :
703	>	((Comparable)k).compareTo(x));
704	>	}
705
706	<	/**
266	<	* The table is rehashed when its size exceeds this threshold.
267	<	* (The value of this field is always <tt>(int)(capacity *
268	<	* loadFactor)</tt>.)
269	<	*/
270	<	transient int threshold;
706	>	/* ---------------- Table element access -------------- */
707
708	<	/**
709	<	* The per-segment table.
710	<	*/
711	<	transient volatile HashEntry<K,V>[] table;
708	>	/*
709	>	* Volatile access methods are used for table elements as well as
710	>	* elements of in-progress next table while resizing.  All uses of
711	>	* the tab arguments must be null checked by callers.  All callers
712	>	* also paranoically precheck that tab's length is not zero (or an
713	>	* equivalent check), thus ensuring that any index argument taking
714	>	* the form of a hash value anded with (length - 1) is a valid
715	>	* index.  Note that, to be correct wrt arbitrary concurrency
716	>	* errors by users, these checks must operate on local variables,
717	>	* which accounts for some odd-looking inline assignments below.
718	>	* Note that calls to setTabAt always occur within locked regions,
719	>	* and so in principle require only release ordering, not
720	>	* full volatile semantics, but are currently coded as volatile
721	>	* writes to be conservative.
722	>	*/
723	>
724	>	@SuppressWarnings("unchecked")
725	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
726	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
727	>	}
728
729	<	/**
730	<	* The load factor for the hash table.  Even though this value
731	<	* is same for all segments, it is replicated to avoid needing
732	<	* links to outer object.
281	<	* @serial
282	<	*/
283	<	final float loadFactor;
729	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
730	>	Node<K,V> c, Node<K,V> v) {
731	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
732	>	}
733
734	<	Segment(int initialCapacity, float lf) {
735	<	loadFactor = lf;
736	<	setTable(HashEntry.<K,V>newArray(initialCapacity));
288	<	}
734	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
735	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
736	>	}
737
738	<	@SuppressWarnings("unchecked")
291	<	static final <K,V> Segment<K,V>[] newArray(int i) {
292	<	return new Segment[i];
293	<	}
738	>	/* ---------------- Fields -------------- */
739
740	<	/**
741	<	* Sets table to new HashEntry array.
742	<	* Call only while holding lock or in constructor.
743	<	*/
744	<	void setTable(HashEntry<K,V>[] newTable) {
300	<	threshold = (int)(newTable.length * loadFactor);
301	<	table = newTable;
302	<	}
740	>	/**
741	>	* The array of bins. Lazily initialized upon first insertion.
742	>	* Size is always a power of two. Accessed directly by iterators.
743	>	*/
744	>	transient volatile Node<K,V>[] table;
745
746	<	/**
747	<	* Returns properly casted first entry of bin for given hash.
748	<	*/
749	<	HashEntry<K,V> getFirst(int hash) {
308	<	HashEntry<K,V>[] tab = table;
309	<	return tab[hash & (tab.length - 1)];
310	<	}
746	>	/**
747	>	* The next table to use; non-null only while resizing.
748	>	*/
749	>	private transient volatile Node<K,V>[] nextTable;
750
751	<	/**
752	<	* Reads value field of an entry under lock. Called if value
753	<	* field ever appears to be null. This is possible only if a
754	<	* compiler happens to reorder a HashEntry initialization with
755	<	* its table assignment, which is legal under memory model
756	<	* but is not known to ever occur.
318	<	*/
319	<	V readValueUnderLock(HashEntry<K,V> e) {
320	<	lock();
321	<	try {
322	<	return e.value;
323	<	} finally {
324	<	unlock();
325	<	}
326	<	}
751	>	/**
752	>	* Base counter value, used mainly when there is no contention,
753	>	* but also as a fallback during table initialization
754	>	* races. Updated via CAS.
755	>	*/
756	>	private transient volatile long baseCount;
757
758	<	/* Specialized implementations of map methods */
758	>	/**
759	>	* Table initialization and resizing control.  When negative, the
760	>	* table is being initialized or resized: -1 for initialization,
761	>	* else -(1 + the number of active resizing threads).  Otherwise,
762	>	* when table is null, holds the initial table size to use upon
763	>	* creation, or 0 for default. After initialization, holds the
764	>	* next element count value upon which to resize the table.
765	>	*/
766	>	private transient volatile int sizeCtl;
767
768	<	V get(Object key, int hash) {
769	<	if (count != 0) { // read-volatile
770	<	HashEntry<K,V> e = getFirst(hash);
771	<	while (e != null) {
334	<	if (e.hash == hash && key.equals(e.key)) {
335	<	V v = e.value;
336	<	if (v != null)
337	<	return v;
338	<	return readValueUnderLock(e); // recheck
339	<	}
340	<	e = e.next;
341	<	}
342	<	}
343	<	return null;
344	<	}
768	>	/**
769	>	* The next table index (plus one) to split while resizing.
770	>	*/
771	>	private transient volatile int transferIndex;
772
773	<	boolean containsKey(Object key, int hash) {
774	<	if (count != 0) { // read-volatile
775	<	HashEntry<K,V> e = getFirst(hash);
776	<	while (e != null) {
350	<	if (e.hash == hash && key.equals(e.key))
351	<	return true;
352	<	e = e.next;
353	<	}
354	<	}
355	<	return false;
356	<	}
773	>	/**
774	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
775	>	*/
776	>	private transient volatile int cellsBusy;
777
778	<	boolean containsValue(Object value) {
779	<	if (count != 0) { // read-volatile
780	<	HashEntry<K,V>[] tab = table;
781	<	int len = tab.length;
362	<	for (int i = 0 ; i < len; i++) {
363	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
364	<	V v = e.value;
365	<	if (v == null) // recheck
366	<	v = readValueUnderLock(e);
367	<	if (value.equals(v))
368	<	return true;
369	<	}
370	<	}
371	<	}
372	<	return false;
373	<	}
778	>	/**
779	>	* Table of counter cells. When non-null, size is a power of 2.
780	>	*/
781	>	private transient volatile CounterCell[] counterCells;
782
783	<	boolean replace(K key, int hash, V oldValue, V newValue) {
784	<	lock();
785	<	try {
786	<	HashEntry<K,V> e = getFirst(hash);
787	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
788	<	e = e.next;
789	<
790	<	boolean replaced = false;
791	<	if (e != null && oldValue.equals(e.value)) {
792	<	replaced = true;
793	<	e.value = newValue;
794	<	}
795	<	return replaced;
796	<	} finally {
797	<	unlock();
783	>	// views
784	>	private transient KeySetView<K,V> keySet;
785	>	private transient ValuesView<K,V> values;
786	>	private transient EntrySetView<K,V> entrySet;
787	>
788	>
789	>	/* ---------------- Public operations -------------- */
790	>
791	>	/**
792	>	* Creates a new, empty map with the default initial table size (16).
793	>	*/
794	>	public ConcurrentHashMap() {
795	>	}
796	>
797	>	/**
798	>	* Creates a new, empty map with an initial table size
799	>	* accommodating the specified number of elements without the need
800	>	* to dynamically resize.
801	>	*
802	>	* @param initialCapacity The implementation performs internal
803	>	* sizing to accommodate this many elements.
804	>	* @throws IllegalArgumentException if the initial capacity of
805	>	* elements is negative
806	>	*/
807	>	public ConcurrentHashMap(int initialCapacity) {
808	>	if (initialCapacity < 0)
809	>	throw new IllegalArgumentException();
810	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
811	>	MAXIMUM_CAPACITY :
812	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
813	>	this.sizeCtl = cap;
814	>	}
815	>
816	>	/**
817	>	* Creates a new map with the same mappings as the given map.
818	>	*
819	>	* @param m the map
820	>	*/
821	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
822	>	this.sizeCtl = DEFAULT_CAPACITY;
823	>	putAll(m);
824	>	}
825	>
826	>	/**
827	>	* Creates a new, empty map with an initial table size based on
828	>	* the given number of elements ({@code initialCapacity}) and
829	>	* initial table density ({@code loadFactor}).
830	>	*
831	>	* @param initialCapacity the initial capacity. The implementation
832	>	* performs internal sizing to accommodate this many elements,
833	>	* given the specified load factor.
834	>	* @param loadFactor the load factor (table density) for
835	>	* establishing the initial table size
836	>	* @throws IllegalArgumentException if the initial capacity of
837	>	* elements is negative or the load factor is nonpositive
838	>	*
839	>	* @since 1.6
840	>	*/
841	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
842	>	this(initialCapacity, loadFactor, 1);
843	>	}
844	>
845	>	/**
846	>	* Creates a new, empty map with an initial table size based on
847	>	* the given number of elements ({@code initialCapacity}), table
848	>	* density ({@code loadFactor}), and number of concurrently
849	>	* updating threads ({@code concurrencyLevel}).
850	>	*
851	>	* @param initialCapacity the initial capacity. The implementation
852	>	* performs internal sizing to accommodate this many elements,
853	>	* given the specified load factor.
854	>	* @param loadFactor the load factor (table density) for
855	>	* establishing the initial table size
856	>	* @param concurrencyLevel the estimated number of concurrently
857	>	* updating threads. The implementation may use this value as
858	>	* a sizing hint.
859	>	* @throws IllegalArgumentException if the initial capacity is
860	>	* negative or the load factor or concurrencyLevel are
861	>	* nonpositive
862	>	*/
863	>	public ConcurrentHashMap(int initialCapacity,
864	>	float loadFactor, int concurrencyLevel) {
865	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
866	>	throw new IllegalArgumentException();
867	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
868	>	initialCapacity = concurrencyLevel;   // as estimated threads
869	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
870	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
871	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
872	>	this.sizeCtl = cap;
873	>	}
874	>
875	>	// Original (since JDK1.2) Map methods
876	>
877	>	/**
878	>	* {@inheritDoc}
879	>	*/
880	>	public int size() {
881	>	long n = sumCount();
882	>	return ((n < 0L) ? 0 :
883	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
884	>	(int)n);
885	>	}
886	>
887	>	/**
888	>	* {@inheritDoc}
889	>	*/
890	>	public boolean isEmpty() {
891	>	return sumCount() <= 0L; // ignore transient negative values
892	>	}
893	>
894	>	/**
895	>	* Returns the value to which the specified key is mapped,
896	>	* or {@code null} if this map contains no mapping for the key.
897	>	*
898	>	* <p>More formally, if this map contains a mapping from a key
899	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
900	>	* then this method returns {@code v}; otherwise it returns
901	>	* {@code null}.  (There can be at most one such mapping.)
902	>	*
903	>	* @throws NullPointerException if the specified key is null
904	>	*/
905	>	public V get(Object key) {
906	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
907	>	int h = spread(key.hashCode());
908	>	if ((tab = table) != null && (n = tab.length) > 0 &&
909	>	(e = tabAt(tab, (n - 1) & h)) != null) {
910	>	if ((eh = e.hash) == h) {
911	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
912	>	return e.val;
913	>	}
914	>	else if (eh < 0)
915	>	return (p = e.find(h, key)) != null ? p.val : null;
916	>	while ((e = e.next) != null) {
917	>	if (e.hash == h &&
918	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
919	>	return e.val;
920		}
921		}
922	+	return null;
923	+	}
924
925	<	V replace(K key, int hash, V newValue) {
926	<	lock();
927	<	try {
928	<	HashEntry<K,V> e = getFirst(hash);
929	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
930	<	e = e.next;
931	<
932	<	V oldValue = null;
933	<	if (e != null) {
934	<	oldValue = e.value;
935	<	e.value = newValue;
936	<	}
937	<	return oldValue;
938	<	} finally {
939	<	unlock();
925	>	/**
926	>	* Tests if the specified object is a key in this table.
927	>	*
928	>	* @param  key possible key
929	>	* @return {@code true} if and only if the specified object
930	>	*         is a key in this table, as determined by the
931	>	*         {@code equals} method; {@code false} otherwise
932	>	* @throws NullPointerException if the specified key is null
933	>	*/
934	>	public boolean containsKey(Object key) {
935	>	return get(key) != null;
936	>	}
937	>
938	>	/**
939	>	* Returns {@code true} if this map maps one or more keys to the
940	>	* specified value. Note: This method may require a full traversal
941	>	* of the map, and is much slower than method {@code containsKey}.
942	>	*
943	>	* @param value value whose presence in this map is to be tested
944	>	* @return {@code true} if this map maps one or more keys to the
945	>	*         specified value
946	>	* @throws NullPointerException if the specified value is null
947	>	*/
948	>	public boolean containsValue(Object value) {
949	>	if (value == null)
950	>	throw new NullPointerException();
951	>	Node<K,V>[] t;
952	>	if ((t = table) != null) {
953	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
954	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
955	>	V v;
956	>	if ((v = p.val) == value || (v != null && value.equals(v)))
957	>	return true;
958		}
959		}
960	+	return false;
961	+	}
962
963	+	/**
964	+	* Maps the specified key to the specified value in this table.
965	+	* Neither the key nor the value can be null.
966	+	*
967	+	* <p>The value can be retrieved by calling the {@code get} method
968	+	* with a key that is equal to the original key.
969	+	*
970	+	* @param key key with which the specified value is to be associated
971	+	* @param value value to be associated with the specified key
972	+	* @return the previous value associated with {@code key}, or
973	+	*         {@code null} if there was no mapping for {@code key}
974	+	* @throws NullPointerException if the specified key or value is null
975	+	*/
976	+	public V put(K key, V value) {
977	+	return putVal(key, value, false);
978	+	}
979
980	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
981	<	lock();
982	<	try {
983	<	int c = count;
984	<	if (c++ > threshold) // ensure capacity
985	<	rehash();
986	<	HashEntry<K,V>[] tab = table;
987	<	int index = hash & (tab.length - 1);
988	<	HashEntry<K,V> first = tab[index];
989	<	HashEntry<K,V> e = first;
990	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
991	<	e = e.next;
992	<
993	<	V oldValue;
994	<	if (e != null) {
995	<	oldValue = e.value;
996	<	if (!onlyIfAbsent)
997	<	e.value = value;
980	>	/** Implementation for put and putIfAbsent */
981	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
982	>	if (key == null || value == null) throw new NullPointerException();
983	>	int hash = spread(key.hashCode());
984	>	int binCount = 0;
985	>	for (Node<K,V>[] tab = table;;) {
986	>	Node<K,V> f; int n, i, fh;
987	>	if (tab == null || (n = tab.length) == 0)
988	>	tab = initTable();
989	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
990	>	if (casTabAt(tab, i, null,
991	>	new Node<K,V>(hash, key, value, null)))
992	>	break;                   // no lock when adding to empty bin
993	>	}
994	>	else if ((fh = f.hash) == MOVED)
995	>	tab = helpTransfer(tab, f);
996	>	else {
997	>	V oldVal = null;
998	>	synchronized (f) {
999	>	if (tabAt(tab, i) == f) {
1000	>	if (fh >= 0) {
1001	>	binCount = 1;
1002	>	for (Node<K,V> e = f;; ++binCount) {
1003	>	K ek;
1004	>	if (e.hash == hash &&
1005	>	((ek = e.key) == key ||
1006	>	(ek != null && key.equals(ek)))) {
1007	>	oldVal = e.val;
1008	>	if (!onlyIfAbsent)
1009	>	e.val = value;
1010	>	break;
1011	>	}
1012	>	Node<K,V> pred = e;
1013	>	if ((e = e.next) == null) {
1014	>	pred.next = new Node<K,V>(hash, key,
1015	>	value, null);
1016	>	break;
1017	>	}
1018	>	}
1019	>	}
1020	>	else if (f instanceof TreeBin) {
1021	>	Node<K,V> p;
1022	>	binCount = 2;
1023	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1024	>	value)) != null) {
1025	>	oldVal = p.val;
1026	>	if (!onlyIfAbsent)
1027	>	p.val = value;
1028	>	}
1029	>	}
1030	>	}
1031		}
1032	<	else {
1033	<	oldValue = null;
1034	<	++modCount;
1035	<	tab[index] = new HashEntry<K,V>(key, hash, first, value);
1036	<	count = c; // write-volatile
1032	>	if (binCount != 0) {
1033	>	if (binCount >= TREEIFY_THRESHOLD)
1034	>	treeifyBin(tab, i);
1035	>	if (oldVal != null)
1036	>	return oldVal;
1037	>	break;
1038		}
437	–	return oldValue;
438	–	} finally {
439	–	unlock();
1039		}
1040		}
1041	+	addCount(1L, binCount);
1042	+	return null;
1043	+	}
1044
1045	<	void rehash() {
1046	<	HashEntry<K,V>[] oldTable = table;
1047	<	int oldCapacity = oldTable.length;
1048	<	if (oldCapacity >= MAXIMUM_CAPACITY)
1049	<	return;
1045	>	/**
1046	>	* Copies all of the mappings from the specified map to this one.
1047	>	* These mappings replace any mappings that this map had for any of the
1048	>	* keys currently in the specified map.
1049	>	*
1050	>	* @param m mappings to be stored in this map
1051	>	*/
1052	>	public void putAll(Map<? extends K, ? extends V> m) {
1053	>	tryPresize(m.size());
1054	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1055	>	putVal(e.getKey(), e.getValue(), false);
1056	>	}
1057
1058	<	/*
1059	<	* Reclassify nodes in each list to new Map.  Because we are
1060	<	* using power-of-two expansion, the elements from each bin
1061	<	* must either stay at same index, or move with a power of two
1062	<	* offset. We eliminate unnecessary node creation by catching
1063	<	* cases where old nodes can be reused because their next
1064	<	* fields won't change. Statistically, at the default
1065	<	* threshold, only about one-sixth of them need cloning when
1066	<	* a table doubles. The nodes they replace will be garbage
1067	<	* collectable as soon as they are no longer referenced by any
1068	<	* reader thread that may be in the midst of traversing table
1069	<	* right now.
461	<	*/
462	<
463	<	HashEntry<K,V>[] newTable = HashEntry.newArray(oldCapacity<<1);
464	<	threshold = (int)(newTable.length * loadFactor);
465	<	int sizeMask = newTable.length - 1;
466	<	for (int i = 0; i < oldCapacity ; i++) {
467	<	// We need to guarantee that any existing reads of old Map can
468	<	//  proceed. So we cannot yet null out each bin.
469	<	HashEntry<K,V> e = oldTable[i];
470	<
471	<	if (e != null) {
472	<	HashEntry<K,V> next = e.next;
473	<	int idx = e.hash & sizeMask;
474	<
475	<	//  Single node on list
476	<	if (next == null)
477	<	newTable[idx] = e;
1058	>	/**
1059	>	* Removes the key (and its corresponding value) from this map.
1060	>	* This method does nothing if the key is not in the map.
1061	>	*
1062	>	* @param  key the key that needs to be removed
1063	>	* @return the previous value associated with {@code key}, or
1064	>	*         {@code null} if there was no mapping for {@code key}
1065	>	* @throws NullPointerException if the specified key is null
1066	>	*/
1067	>	public V remove(Object key) {
1068	>	return replaceNode(key, null, null);
1069	>	}
1070
1071	<	else {
1072	<	// Reuse trailing consecutive sequence at same slot
1073	<	HashEntry<K,V> lastRun = e;
1074	<	int lastIdx = idx;
1075	<	for (HashEntry<K,V> last = next;
1076	<	last != null;
1077	<	last = last.next) {
1078	<	int k = last.hash & sizeMask;
1079	<	if (k != lastIdx) {
1080	<	lastIdx = k;
1081	<	lastRun = last;
1071	>	/**
1072	>	* Implementation for the four public remove/replace methods:
1073	>	* Replaces node value with v, conditional upon match of cv if
1074	>	* non-null.  If resulting value is null, delete.
1075	>	*/
1076	>	final V replaceNode(Object key, V value, Object cv) {
1077	>	int hash = spread(key.hashCode());
1078	>	for (Node<K,V>[] tab = table;;) {
1079	>	Node<K,V> f; int n, i, fh;
1080	>	if (tab == null || (n = tab.length) == 0 ||
1081	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1082	>	break;
1083	>	else if ((fh = f.hash) == MOVED)
1084	>	tab = helpTransfer(tab, f);
1085	>	else {
1086	>	V oldVal = null;
1087	>	boolean validated = false;
1088	>	synchronized (f) {
1089	>	if (tabAt(tab, i) == f) {
1090	>	if (fh >= 0) {
1091	>	validated = true;
1092	>	for (Node<K,V> e = f, pred = null;;) {
1093	>	K ek;
1094	>	if (e.hash == hash &&
1095	>	((ek = e.key) == key ||
1096	>	(ek != null && key.equals(ek)))) {
1097	>	V ev = e.val;
1098	>	if (cv == null || cv == ev ||
1099	>	(ev != null && cv.equals(ev))) {
1100	>	oldVal = ev;
1101	>	if (value != null)
1102	>	e.val = value;
1103	>	else if (pred != null)
1104	>	pred.next = e.next;
1105	>	else
1106	>	setTabAt(tab, i, e.next);
1107	>	}
1108	>	break;
1109	>	}
1110	>	pred = e;
1111	>	if ((e = e.next) == null)
1112	>	break;
1113		}
1114		}
1115	<	newTable[lastIdx] = lastRun;
1116	<
1117	<	// Clone all remaining nodes
1118	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1119	<	int k = p.hash & sizeMask;
1120	<	HashEntry<K,V> n = newTable[k];
1121	<	newTable[k] = new HashEntry<K,V>(p.key, p.hash,
1122	<	n, p.value);
1115	>	else if (f instanceof TreeBin) {
1116	>	validated = true;
1117	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1118	>	TreeNode<K,V> r, p;
1119	>	if ((r = t.root) != null &&
1120	>	(p = r.findTreeNode(hash, key, null)) != null) {
1121	>	V pv = p.val;
1122	>	if (cv == null || cv == pv ||
1123	>	(pv != null && cv.equals(pv))) {
1124	>	oldVal = pv;
1125	>	if (value != null)
1126	>	p.val = value;
1127	>	else if (t.removeTreeNode(p))
1128	>	setTabAt(tab, i, untreeify(t.first));
1129	>	}
1130	>	}
1131		}
1132		}
1133		}
1134	<	}
1135	<	table = newTable;
1136	<	}
1137	<
1138	<	/**
508	<	* Remove; match on key only if value null, else match both.
509	<	*/
510	<	V remove(Object key, int hash, Object value) {
511	<	lock();
512	<	try {
513	<	int c = count - 1;
514	<	HashEntry<K,V>[] tab = table;
515	<	int index = hash & (tab.length - 1);
516	<	HashEntry<K,V> first = tab[index];
517	<	HashEntry<K,V> e = first;
518	<	while (e != null && (e.hash != hash || !key.equals(e.key)))
519	<	e = e.next;
520	<
521	<	V oldValue = null;
522	<	if (e != null) {
523	<	V v = e.value;
524	<	if (value == null || value.equals(v)) {
525	<	oldValue = v;
526	<	// All entries following removed node can stay
527	<	// in list, but all preceding ones need to be
528	<	// cloned.
529	<	++modCount;
530	<	HashEntry<K,V> newFirst = e.next;
531	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
532	<	newFirst = new HashEntry<K,V>(p.key, p.hash,
533	<	newFirst, p.value);
534	<	tab[index] = newFirst;
535	<	count = c; // write-volatile
1134	>	if (validated) {
1135	>	if (oldVal != null) {
1136	>	if (value == null)
1137	>	addCount(-1L, -1);
1138	>	return oldVal;
1139		}
1140	+	break;
1141		}
538	–	return oldValue;
539	–	} finally {
540	–	unlock();
1142		}
1143		}
1144	+	return null;
1145	+	}
1146
1147	<	void clear() {
1148	<	if (count != 0) {
1149	<	lock();
1150	<	try {
1151	<	HashEntry<K,V>[] tab = table;
1152	<	for (int i = 0; i < tab.length ; i++)
1153	<	tab[i] = null;
1154	<	++modCount;
1155	<	count = 0; // write-volatile
1156	<	} finally {
1157	<	unlock();
1147	>	/**
1148	>	* Removes all of the mappings from this map.
1149	>	*/
1150	>	public void clear() {
1151	>	long delta = 0L; // negative number of deletions
1152	>	int i = 0;
1153	>	Node<K,V>[] tab = table;
1154	>	while (tab != null && i < tab.length) {
1155	>	int fh;
1156	>	Node<K,V> f = tabAt(tab, i);
1157	>	if (f == null)
1158	>	++i;
1159	>	else if ((fh = f.hash) == MOVED) {
1160	>	tab = helpTransfer(tab, f);
1161	>	i = 0; // restart
1162	>	}
1163	>	else {
1164	>	synchronized (f) {
1165	>	if (tabAt(tab, i) == f) {
1166	>	Node<K,V> p = (fh >= 0 ? f :
1167	>	(f instanceof TreeBin) ?
1168	>	((TreeBin<K,V>)f).first : null);
1169	>	while (p != null) {
1170	>	--delta;
1171	>	p = p.next;
1172	>	}
1173	>	setTabAt(tab, i++, null);
1174	>	}
1175		}
1176		}
1177		}
1178	+	if (delta != 0L)
1179	+	addCount(delta, -1);
1180		}
1181
1182	+	/**
1183	+	* Returns a {@link Set} view of the keys contained in this map.
1184	+	* The set is backed by the map, so changes to the map are
1185	+	* reflected in the set, and vice-versa. The set supports element
1186	+	* removal, which removes the corresponding mapping from this map,
1187	+	* via the {@code Iterator.remove}, {@code Set.remove},
1188	+	* {@code removeAll}, {@code retainAll}, and {@code clear}
1189	+	* operations.  It does not support the {@code add} or
1190	+	* {@code addAll} operations.
1191	+	*
1192	+	* <p>The view's iterators and spliterators are
1193	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1194	+	*
1195	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1196	+	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1197	+	*
1198	+	* @return the set view
1199	+	*/
1200	+	public KeySetView<K,V> keySet() {
1201	+	KeySetView<K,V> ks;
1202	+	return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1203	+	}
1204
1205	+	/**
1206	+	* Returns a {@link Collection} view of the values contained in this map.
1207	+	* The collection is backed by the map, so changes to the map are
1208	+	* reflected in the collection, and vice-versa.  The collection
1209	+	* supports element removal, which removes the corresponding
1210	+	* mapping from this map, via the {@code Iterator.remove},
1211	+	* {@code Collection.remove}, {@code removeAll},
1212	+	* {@code retainAll}, and {@code clear} operations.  It does not
1213	+	* support the {@code add} or {@code addAll} operations.
1214	+	*
1215	+	* <p>The view's iterators and spliterators are
1216	+	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1217	+	*
1218	+	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1219	+	* and {@link Spliterator#NONNULL}.
1220	+	*
1221	+	* @return the collection view
1222	+	*/
1223	+	public Collection<V> values() {
1224	+	ValuesView<K,V> vs;
1225	+	return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1226	+	}
1227
1228	<	/* ---------------- Public operations -------------- */
1228	>	/**
1229	>	* Returns a {@link Set} view of the mappings contained in this map.
1230	>	* The set is backed by the map, so changes to the map are
1231	>	* reflected in the set, and vice-versa.  The set supports element
1232	>	* removal, which removes the corresponding mapping from the map,
1233	>	* via the {@code Iterator.remove}, {@code Set.remove},
1234	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1235	>	* operations.
1236	>	*
1237	>	* <p>The view's iterators and spliterators are
1238	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1239	>	*
1240	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1241	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1242	>	*
1243	>	* @return the set view
1244	>	*/
1245	>	public Set<Map.Entry<K,V>> entrySet() {
1246	>	EntrySetView<K,V> es;
1247	>	return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1248	>	}
1249
1250		/**
1251	<	* Creates a new, empty map with the specified initial
1252	<	* capacity, load factor and concurrency level.
1251	>	* Returns the hash code value for this {@link Map}, i.e.,
1252	>	* the sum of, for each key-value pair in the map,
1253	>	* {@code key.hashCode() ^ value.hashCode()}.
1254		*
1255	<	* @param initialCapacity the initial capacity. The implementation
569	<	* performs internal sizing to accommodate this many elements.
570	<	* @param loadFactor  the load factor threshold, used to control resizing.
571	<	* Resizing may be performed when the average number of elements per
572	<	* bin exceeds this threshold.
573	<	* @param concurrencyLevel the estimated number of concurrently
574	<	* updating threads. The implementation performs internal sizing
575	<	* to try to accommodate this many threads.
576	<	* @throws IllegalArgumentException if the initial capacity is
577	<	* negative or the load factor or concurrencyLevel are
578	<	* nonpositive.
1255	>	* @return the hash code value for this map
1256		*/
1257	<	public ConcurrentHashMap(int initialCapacity,
1258	<	float loadFactor, int concurrencyLevel) {
1259	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
1260	<	throw new IllegalArgumentException();
1257	>	public int hashCode() {
1258	>	int h = 0;
1259	>	Node<K,V>[] t;
1260	>	if ((t = table) != null) {
1261	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1262	>	for (Node<K,V> p; (p = it.advance()) != null; )
1263	>	h += p.key.hashCode() ^ p.val.hashCode();
1264	>	}
1265	>	return h;
1266	>	}
1267	>
1268	>	/**
1269	>	* Returns a string representation of this map.  The string
1270	>	* representation consists of a list of key-value mappings (in no
1271	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1272	>	* mappings are separated by the characters {@code ", "} (comma
1273	>	* and space).  Each key-value mapping is rendered as the key
1274	>	* followed by an equals sign ("{@code =}") followed by the
1275	>	* associated value.
1276	>	*
1277	>	* @return a string representation of this map
1278	>	*/
1279	>	public String toString() {
1280	>	Node<K,V>[] t;
1281	>	int f = (t = table) == null ? 0 : t.length;
1282	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1283	>	StringBuilder sb = new StringBuilder();
1284	>	sb.append('{');
1285	>	Node<K,V> p;
1286	>	if ((p = it.advance()) != null) {
1287	>	for (;;) {
1288	>	K k = p.key;
1289	>	V v = p.val;
1290	>	sb.append(k == this ? "(this Map)" : k);
1291	>	sb.append('=');
1292	>	sb.append(v == this ? "(this Map)" : v);
1293	>	if ((p = it.advance()) == null)
1294	>	break;
1295	>	sb.append(',').append(' ');
1296	>	}
1297	>	}
1298	>	return sb.append('}').toString();
1299	>	}
1300	>
1301	>	/**
1302	>	* Compares the specified object with this map for equality.
1303	>	* Returns {@code true} if the given object is a map with the same
1304	>	* mappings as this map.  This operation may return misleading
1305	>	* results if either map is concurrently modified during execution
1306	>	* of this method.
1307	>	*
1308	>	* @param o object to be compared for equality with this map
1309	>	* @return {@code true} if the specified object is equal to this map
1310	>	*/
1311	>	public boolean equals(Object o) {
1312	>	if (o != this) {
1313	>	if (!(o instanceof Map))
1314	>	return false;
1315	>	Map<?,?> m = (Map<?,?>) o;
1316	>	Node<K,V>[] t;
1317	>	int f = (t = table) == null ? 0 : t.length;
1318	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1319	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1320	>	V val = p.val;
1321	>	Object v = m.get(p.key);
1322	>	if (v == null || (v != val && !v.equals(val)))
1323	>	return false;
1324	>	}
1325	>	for (Map.Entry<?,?> e : m.entrySet()) {
1326	>	Object mk, mv, v;
1327	>	if ((mk = e.getKey()) == null ||
1328	>	(mv = e.getValue()) == null ||
1329	>	(v = get(mk)) == null ||
1330	>	(mv != v && !mv.equals(v)))
1331	>	return false;
1332	>	}
1333	>	}
1334	>	return true;
1335	>	}
1336
1337	<	if (concurrencyLevel > MAX_SEGMENTS)
1338	<	concurrencyLevel = MAX_SEGMENTS;
1337	>	/**
1338	>	* Stripped-down version of helper class used in previous version,
1339	>	* declared for the sake of serialization compatibility
1340	>	*/
1341	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1342	>	private static final long serialVersionUID = 2249069246763182397L;
1343	>	final float loadFactor;
1344	>	Segment(float lf) { this.loadFactor = lf; }
1345	>	}
1346
1347	<	// Find power-of-two sizes best matching arguments
1347	>	/**
1348	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1349	>	* stream (i.e., serializes it).
1350	>	* @param s the stream
1351	>	* @throws java.io.IOException if an I/O error occurs
1352	>	* @serialData
1353	>	* the key (Object) and value (Object)
1354	>	* for each key-value mapping, followed by a null pair.
1355	>	* The key-value mappings are emitted in no particular order.
1356	>	*/
1357	>	private void writeObject(java.io.ObjectOutputStream s)
1358	>	throws java.io.IOException {
1359	>	// For serialization compatibility
1360	>	// Emulate segment calculation from previous version of this class
1361		int sshift = 0;
1362		int ssize = 1;
1363	<	while (ssize < concurrencyLevel) {
1363	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1364		++sshift;
1365		ssize <<= 1;
1366		}
1367	<	segmentShift = 32 - sshift;
1368	<	segmentMask = ssize - 1;
1369	<	this.segments = Segment.newArray(ssize);
1370	<
1371	<	if (initialCapacity > MAXIMUM_CAPACITY)
1372	<	initialCapacity = MAXIMUM_CAPACITY;
1373	<	int c = initialCapacity / ssize;
1374	<	if (c * ssize < initialCapacity)
1375	<	++c;
1376	<	int cap = 1;
1377	<	while (cap < c)
1378	<	cap <<= 1;
1367	>	int segmentShift = 32 - sshift;
1368	>	int segmentMask = ssize - 1;
1369	>	@SuppressWarnings("unchecked")
1370	>	Segment<K,V>[] segments = (Segment<K,V>[])
1371	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1372	>	for (int i = 0; i < segments.length; ++i)
1373	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1374	>	s.putFields().put("segments", segments);
1375	>	s.putFields().put("segmentShift", segmentShift);
1376	>	s.putFields().put("segmentMask", segmentMask);
1377	>	s.writeFields();
1378	>
1379	>	Node<K,V>[] t;
1380	>	if ((t = table) != null) {
1381	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1382	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1383	>	s.writeObject(p.key);
1384	>	s.writeObject(p.val);
1385	>	}
1386	>	}
1387	>	s.writeObject(null);
1388	>	s.writeObject(null);
1389	>	segments = null; // throw away
1390	>	}
1391
1392	<	for (int i = 0; i < this.segments.length; ++i)
1393	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
1392	>	/**
1393	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1394	>	* @param s the stream
1395	>	* @throws ClassNotFoundException if the class of a serialized object
1396	>	*         could not be found
1397	>	* @throws java.io.IOException if an I/O error occurs
1398	>	*/
1399	>	private void readObject(java.io.ObjectInputStream s)
1400	>	throws java.io.IOException, ClassNotFoundException {
1401	>	/*
1402	>	* To improve performance in typical cases, we create nodes
1403	>	* while reading, then place in table once size is known.
1404	>	* However, we must also validate uniqueness and deal with
1405	>	* overpopulated bins while doing so, which requires
1406	>	* specialized versions of putVal mechanics.
1407	>	*/
1408	>	sizeCtl = -1; // force exclusion for table construction
1409	>	s.defaultReadObject();
1410	>	long size = 0L;
1411	>	Node<K,V> p = null;
1412	>	for (;;) {
1413	>	@SuppressWarnings("unchecked")
1414	>	K k = (K) s.readObject();
1415	>	@SuppressWarnings("unchecked")
1416	>	V v = (V) s.readObject();
1417	>	if (k != null && v != null) {
1418	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1419	>	++size;
1420	>	}
1421	>	else
1422	>	break;
1423	>	}
1424	>	if (size == 0L)
1425	>	sizeCtl = 0;
1426	>	else {
1427	>	int n;
1428	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1429	>	n = MAXIMUM_CAPACITY;
1430	>	else {
1431	>	int sz = (int)size;
1432	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1433	>	}
1434	>	@SuppressWarnings("unchecked")
1435	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1436	>	int mask = n - 1;
1437	>	long added = 0L;
1438	>	while (p != null) {
1439	>	boolean insertAtFront;
1440	>	Node<K,V> next = p.next, first;
1441	>	int h = p.hash, j = h & mask;
1442	>	if ((first = tabAt(tab, j)) == null)
1443	>	insertAtFront = true;
1444	>	else {
1445	>	K k = p.key;
1446	>	if (first.hash < 0) {
1447	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1448	>	if (t.putTreeVal(h, k, p.val) == null)
1449	>	++added;
1450	>	insertAtFront = false;
1451	>	}
1452	>	else {
1453	>	int binCount = 0;
1454	>	insertAtFront = true;
1455	>	Node<K,V> q; K qk;
1456	>	for (q = first; q != null; q = q.next) {
1457	>	if (q.hash == h &&
1458	>	((qk = q.key) == k ||
1459	>	(qk != null && k.equals(qk)))) {
1460	>	insertAtFront = false;
1461	>	break;
1462	>	}
1463	>	++binCount;
1464	>	}
1465	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1466	>	insertAtFront = false;
1467	>	++added;
1468	>	p.next = first;
1469	>	TreeNode<K,V> hd = null, tl = null;
1470	>	for (q = p; q != null; q = q.next) {
1471	>	TreeNode<K,V> t = new TreeNode<K,V>
1472	>	(q.hash, q.key, q.val, null, null);
1473	>	if ((t.prev = tl) == null)
1474	>	hd = t;
1475	>	else
1476	>	tl.next = t;
1477	>	tl = t;
1478	>	}
1479	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1480	>	}
1481	>	}
1482	>	}
1483	>	if (insertAtFront) {
1484	>	++added;
1485	>	p.next = first;
1486	>	setTabAt(tab, j, p);
1487	>	}
1488	>	p = next;
1489	>	}
1490	>	table = tab;
1491	>	sizeCtl = n - (n >>> 2);
1492	>	baseCount = added;
1493	>	}
1494		}
1495
1496	+	// ConcurrentMap methods
1497	+
1498		/**
1499	<	* Creates a new, empty map with the specified initial capacity
614	<	* and load factor and with the default concurrencyLevel (16).
615	<	*
616	<	* @param initialCapacity The implementation performs internal
617	<	* sizing to accommodate this many elements.
618	<	* @param loadFactor  the load factor threshold, used to control resizing.
619	<	* Resizing may be performed when the average number of elements per
620	<	* bin exceeds this threshold.
621	<	* @throws IllegalArgumentException if the initial capacity of
622	<	* elements is negative or the load factor is nonpositive
1499	>	* {@inheritDoc}
1500		*
1501	<	* @since 1.6
1501	>	* @return the previous value associated with the specified key,
1502	>	*         or {@code null} if there was no mapping for the key
1503	>	* @throws NullPointerException if the specified key or value is null
1504		*/
1505	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
1506	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1505	>	public V putIfAbsent(K key, V value) {
1506	>	return putVal(key, value, true);
1507		}
1508
1509		/**
1510	<	* Creates a new, empty map with the specified initial capacity,
632	<	* and with default load factor (0.75) and concurrencyLevel (16).
1510	>	* {@inheritDoc}
1511		*
1512	<	* @param initialCapacity the initial capacity. The implementation
635	<	* performs internal sizing to accommodate this many elements.
636	<	* @throws IllegalArgumentException if the initial capacity of
637	<	* elements is negative.
1512	>	* @throws NullPointerException if the specified key is null
1513		*/
1514	<	public ConcurrentHashMap(int initialCapacity) {
1515	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1514	>	public boolean remove(Object key, Object value) {
1515	>	if (key == null)
1516	>	throw new NullPointerException();
1517	>	return value != null && replaceNode(key, null, value) != null;
1518		}
1519
1520		/**
1521	<	* Creates a new, empty map with a default initial capacity (16),
1522	<	* load factor (0.75) and concurrencyLevel (16).
1521	>	* {@inheritDoc}
1522	>	*
1523	>	* @throws NullPointerException if any of the arguments are null
1524		*/
1525	<	public ConcurrentHashMap() {
1526	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1525	>	public boolean replace(K key, V oldValue, V newValue) {
1526	>	if (key == null || oldValue == null || newValue == null)
1527	>	throw new NullPointerException();
1528	>	return replaceNode(key, newValue, oldValue) != null;
1529		}
1530
1531		/**
1532	<	* Creates a new map with the same mappings as the given map.
653	<	* The map is created with a capacity of 1.5 times the number
654	<	* of mappings in the given map or 16 (whichever is greater),
655	<	* and a default load factor (0.75) and concurrencyLevel (16).
1532	>	* {@inheritDoc}
1533		*
1534	<	* @param m the map
1534	>	* @return the previous value associated with the specified key,
1535	>	*         or {@code null} if there was no mapping for the key
1536	>	* @throws NullPointerException if the specified key or value is null
1537		*/
1538	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
1539	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
1540	<	DEFAULT_INITIAL_CAPACITY),
1541	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
663	<	putAll(m);
1538	>	public V replace(K key, V value) {
1539	>	if (key == null || value == null)
1540	>	throw new NullPointerException();
1541	>	return replaceNode(key, value, null);
1542		}
1543
1544	+	// Overrides of JDK8+ Map extension method defaults
1545	+
1546		/**
1547	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
1547	>	* Returns the value to which the specified key is mapped, or the
1548	>	* given default value if this map contains no mapping for the
1549	>	* key.
1550		*
1551	<	* @return <tt>true</tt> if this map contains no key-value mappings
1551	>	* @param key the key whose associated value is to be returned
1552	>	* @param defaultValue the value to return if this map contains
1553	>	* no mapping for the given key
1554	>	* @return the mapping for the key, if present; else the default value
1555	>	* @throws NullPointerException if the specified key is null
1556		*/
1557	<	public boolean isEmpty() {
1558	<	final Segment<K,V>[] segments = this.segments;
1559	<	/*
1560	<	* We keep track of per-segment modCounts to avoid ABA
1561	<	* problems in which an element in one segment was added and
1562	<	* in another removed during traversal, in which case the
1563	<	* table was never actually empty at any point. Note the
1564	<	* similar use of modCounts in the size() and containsValue()
1565	<	* methods, which are the only other methods also susceptible
1566	<	* to ABA problems.
1567	<	*/
1568	<	int[] mc = new int[segments.length];
1569	<	int mcsum = 0;
684	<	for (int i = 0; i < segments.length; ++i) {
685	<	if (segments[i].count != 0)
686	<	return false;
687	<	else
688	<	mcsum += mc[i] = segments[i].modCount;
1557	>	public V getOrDefault(Object key, V defaultValue) {
1558	>	V v;
1559	>	return (v = get(key)) == null ? defaultValue : v;
1560	>	}
1561	>
1562	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1563	>	if (action == null) throw new NullPointerException();
1564	>	Node<K,V>[] t;
1565	>	if ((t = table) != null) {
1566	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1567	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1568	>	action.accept(p.key, p.val);
1569	>	}
1570		}
1571	<	// If mcsum happens to be zero, then we know we got a snapshot
1572	<	// before any modifications at all were made.  This is
1573	<	// probably common enough to bother tracking.
1574	<	if (mcsum != 0) {
1575	<	for (int i = 0; i < segments.length; ++i) {
1576	<	if (segments[i].count != 0 ||
1577	<	mc[i] != segments[i].modCount)
1578	<	return false;
1571	>	}
1572	>
1573	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1574	>	if (function == null) throw new NullPointerException();
1575	>	Node<K,V>[] t;
1576	>	if ((t = table) != null) {
1577	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1578	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1579	>	V oldValue = p.val;
1580	>	for (K key = p.key;;) {
1581	>	V newValue = function.apply(key, oldValue);
1582	>	if (newValue == null)
1583	>	throw new NullPointerException();
1584	>	if (replaceNode(key, newValue, oldValue) != null ||
1585	>	(oldValue = get(key)) == null)
1586	>	break;
1587	>	}
1588		}
1589		}
700	–	return true;
1590		}
1591
1592		/**
1593	<	* Returns the number of key-value mappings in this map.  If the
1594	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
1595	<	* <tt>Integer.MAX_VALUE</tt>.
1593	>	* If the specified key is not already associated with a value,
1594	>	* attempts to compute its value using the given mapping function
1595	>	* and enters it into this map unless {@code null}.  The entire
1596	>	* method invocation is performed atomically, so the function is
1597	>	* applied at most once per key.  Some attempted update operations
1598	>	* on this map by other threads may be blocked while computation
1599	>	* is in progress, so the computation should be short and simple,
1600	>	* and must not attempt to update any other mappings of this map.
1601		*
1602	<	* @return the number of key-value mappings in this map
1602	>	* @param key key with which the specified value is to be associated
1603	>	* @param mappingFunction the function to compute a value
1604	>	* @return the current (existing or computed) value associated with
1605	>	*         the specified key, or null if the computed value is null
1606	>	* @throws NullPointerException if the specified key or mappingFunction
1607	>	*         is null
1608	>	* @throws IllegalStateException if the computation detectably
1609	>	*         attempts a recursive update to this map that would
1610	>	*         otherwise never complete
1611	>	* @throws RuntimeException or Error if the mappingFunction does so,
1612	>	*         in which case the mapping is left unestablished
1613		*/
1614	<	public int size() {
1615	<	final Segment<K,V>[] segments = this.segments;
1616	<	long sum = 0;
1617	<	long check = 0;
1618	<	int[] mc = new int[segments.length];
1619	<	// Try a few times to get accurate count. On failure due to
1620	<	// continuous async changes in table, resort to locking.
1621	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1622	<	check = 0;
1623	<	sum = 0;
1624	<	int mcsum = 0;
1625	<	for (int i = 0; i < segments.length; ++i) {
1626	<	sum += segments[i].count;
1627	<	mcsum += mc[i] = segments[i].modCount;
1628	<	}
1629	<	if (mcsum != 0) {
1630	<	for (int i = 0; i < segments.length; ++i) {
1631	<	check += segments[i].count;
1632	<	if (mc[i] != segments[i].modCount) {
1633	<	check = -1; // force retry
1634	<	break;
1614	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1615	>	if (key == null || mappingFunction == null)
1616	>	throw new NullPointerException();
1617	>	int h = spread(key.hashCode());
1618	>	V val = null;
1619	>	int binCount = 0;
1620	>	for (Node<K,V>[] tab = table;;) {
1621	>	Node<K,V> f; int n, i, fh;
1622	>	if (tab == null || (n = tab.length) == 0)
1623	>	tab = initTable();
1624	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1625	>	Node<K,V> r = new ReservationNode<K,V>();
1626	>	synchronized (r) {
1627	>	if (casTabAt(tab, i, null, r)) {
1628	>	binCount = 1;
1629	>	Node<K,V> node = null;
1630	>	try {
1631	>	if ((val = mappingFunction.apply(key)) != null)
1632	>	node = new Node<K,V>(h, key, val, null);
1633	>	} finally {
1634	>	setTabAt(tab, i, node);
1635	>	}
1636		}
1637		}
1638	+	if (binCount != 0)
1639	+	break;
1640	+	}
1641	+	else if ((fh = f.hash) == MOVED)
1642	+	tab = helpTransfer(tab, f);
1643	+	else {
1644	+	boolean added = false;
1645	+	synchronized (f) {
1646	+	if (tabAt(tab, i) == f) {
1647	+	if (fh >= 0) {
1648	+	binCount = 1;
1649	+	for (Node<K,V> e = f;; ++binCount) {
1650	+	K ek; V ev;
1651	+	if (e.hash == h &&
1652	+	((ek = e.key) == key ||
1653	+	(ek != null && key.equals(ek)))) {
1654	+	val = e.val;
1655	+	break;
1656	+	}
1657	+	Node<K,V> pred = e;
1658	+	if ((e = e.next) == null) {
1659	+	if ((val = mappingFunction.apply(key)) != null) {
1660	+	added = true;
1661	+	pred.next = new Node<K,V>(h, key, val, null);
1662	+	}
1663	+	break;
1664	+	}
1665	+	}
1666	+	}
1667	+	else if (f instanceof TreeBin) {
1668	+	binCount = 2;
1669	+	TreeBin<K,V> t = (TreeBin<K,V>)f;
1670	+	TreeNode<K,V> r, p;
1671	+	if ((r = t.root) != null &&
1672	+	(p = r.findTreeNode(h, key, null)) != null)
1673	+	val = p.val;
1674	+	else if ((val = mappingFunction.apply(key)) != null) {
1675	+	added = true;
1676	+	t.putTreeVal(h, key, val);
1677	+	}
1678	+	}
1679	+	}
1680	+	}
1681	+	if (binCount != 0) {
1682	+	if (binCount >= TREEIFY_THRESHOLD)
1683	+	treeifyBin(tab, i);
1684	+	if (!added)
1685	+	return val;
1686	+	break;
1687	+	}
1688		}
734	–	if (check == sum)
735	–	break;
1689		}
1690	<	if (check != sum) { // Resort to locking all segments
1691	<	sum = 0;
1692	<	for (int i = 0; i < segments.length; ++i)
740	<	segments[i].lock();
741	<	for (int i = 0; i < segments.length; ++i)
742	<	sum += segments[i].count;
743	<	for (int i = 0; i < segments.length; ++i)
744	<	segments[i].unlock();
745	<	}
746	<	if (sum > Integer.MAX_VALUE)
747	<	return Integer.MAX_VALUE;
748	<	else
749	<	return (int)sum;
1690	>	if (val != null)
1691	>	addCount(1L, binCount);
1692	>	return val;
1693		}
1694
1695		/**
1696	<	* Returns the value to which this map maps the specified key, or
1697	<	* <tt>null</tt> if the map contains no mapping for the key.
1698	<	*
1699	<	* @param key key whose associated value is to be returned
1700	<	* @return the value to which this map maps the specified key, or
1701	<	*         <tt>null</tt> if the map contains no mapping for the key
1702	<	* @throws NullPointerException if the specified key is null
1696	>	* If the value for the specified key is present, attempts to
1697	>	* compute a new mapping given the key and its current mapped
1698	>	* value.  The entire method invocation is performed atomically.
1699	>	* Some attempted update operations on this map by other threads
1700	>	* may be blocked while computation is in progress, so the
1701	>	* computation should be short and simple, and must not attempt to
1702	>	* update any other mappings of this map.
1703	>	*
1704	>	* @param key key with which a value may be associated
1705	>	* @param remappingFunction the function to compute a value
1706	>	* @return the new value associated with the specified key, or null if none
1707	>	* @throws NullPointerException if the specified key or remappingFunction
1708	>	*         is null
1709	>	* @throws IllegalStateException if the computation detectably
1710	>	*         attempts a recursive update to this map that would
1711	>	*         otherwise never complete
1712	>	* @throws RuntimeException or Error if the remappingFunction does so,
1713	>	*         in which case the mapping is unchanged
1714		*/
1715	<	public V get(Object key) {
1716	<	int hash = hash(key); // throws NullPointerException if key null
1717	<	return segmentFor(hash).get(key, hash);
1715	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1716	>	if (key == null || remappingFunction == null)
1717	>	throw new NullPointerException();
1718	>	int h = spread(key.hashCode());
1719	>	V val = null;
1720	>	int delta = 0;
1721	>	int binCount = 0;
1722	>	for (Node<K,V>[] tab = table;;) {
1723	>	Node<K,V> f; int n, i, fh;
1724	>	if (tab == null || (n = tab.length) == 0)
1725	>	tab = initTable();
1726	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1727	>	break;
1728	>	else if ((fh = f.hash) == MOVED)
1729	>	tab = helpTransfer(tab, f);
1730	>	else {
1731	>	synchronized (f) {
1732	>	if (tabAt(tab, i) == f) {
1733	>	if (fh >= 0) {
1734	>	binCount = 1;
1735	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1736	>	K ek;
1737	>	if (e.hash == h &&
1738	>	((ek = e.key) == key ||
1739	>	(ek != null && key.equals(ek)))) {
1740	>	val = remappingFunction.apply(key, e.val);
1741	>	if (val != null)
1742	>	e.val = val;
1743	>	else {
1744	>	delta = -1;
1745	>	Node<K,V> en = e.next;
1746	>	if (pred != null)
1747	>	pred.next = en;
1748	>	else
1749	>	setTabAt(tab, i, en);
1750	>	}
1751	>	break;
1752	>	}
1753	>	pred = e;
1754	>	if ((e = e.next) == null)
1755	>	break;
1756	>	}
1757	>	}
1758	>	else if (f instanceof TreeBin) {
1759	>	binCount = 2;
1760	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1761	>	TreeNode<K,V> r, p;
1762	>	if ((r = t.root) != null &&
1763	>	(p = r.findTreeNode(h, key, null)) != null) {
1764	>	val = remappingFunction.apply(key, p.val);
1765	>	if (val != null)
1766	>	p.val = val;
1767	>	else {
1768	>	delta = -1;
1769	>	if (t.removeTreeNode(p))
1770	>	setTabAt(tab, i, untreeify(t.first));
1771	>	}
1772	>	}
1773	>	}
1774	>	}
1775	>	}
1776	>	if (binCount != 0)
1777	>	break;
1778	>	}
1779	>	}
1780	>	if (delta != 0)
1781	>	addCount((long)delta, binCount);
1782	>	return val;
1783		}
1784
1785		/**
1786	<	* Tests if the specified object is a key in this table.
1786	>	* Attempts to compute a mapping for the specified key and its
1787	>	* current mapped value (or {@code null} if there is no current
1788	>	* mapping). The entire method invocation is performed atomically.
1789	>	* Some attempted update operations on this map by other threads
1790	>	* may be blocked while computation is in progress, so the
1791	>	* computation should be short and simple, and must not attempt to
1792	>	* update any other mappings of this Map.
1793		*
1794	<	* @param  key   possible key
1795	<	* @return <tt>true</tt> if and only if the specified object
1796	<	*         is a key in this table, as determined by the
1797	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
1798	<	* @throws NullPointerException if the specified key is null
1799	<	*/
1800	<	public boolean containsKey(Object key) {
1801	<	int hash = hash(key); // throws NullPointerException if key null
1802	<	return segmentFor(hash).containsKey(key, hash);
1794	>	* @param key key with which the specified value is to be associated
1795	>	* @param remappingFunction the function to compute a value
1796	>	* @return the new value associated with the specified key, or null if none
1797	>	* @throws NullPointerException if the specified key or remappingFunction
1798	>	*         is null
1799	>	* @throws IllegalStateException if the computation detectably
1800	>	*         attempts a recursive update to this map that would
1801	>	*         otherwise never complete
1802	>	* @throws RuntimeException or Error if the remappingFunction does so,
1803	>	*         in which case the mapping is unchanged
1804	>	*/
1805	>	public V compute(K key,
1806	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1807	>	if (key == null || remappingFunction == null)
1808	>	throw new NullPointerException();
1809	>	int h = spread(key.hashCode());
1810	>	V val = null;
1811	>	int delta = 0;
1812	>	int binCount = 0;
1813	>	for (Node<K,V>[] tab = table;;) {
1814	>	Node<K,V> f; int n, i, fh;
1815	>	if (tab == null || (n = tab.length) == 0)
1816	>	tab = initTable();
1817	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1818	>	Node<K,V> r = new ReservationNode<K,V>();
1819	>	synchronized (r) {
1820	>	if (casTabAt(tab, i, null, r)) {
1821	>	binCount = 1;
1822	>	Node<K,V> node = null;
1823	>	try {
1824	>	if ((val = remappingFunction.apply(key, null)) != null) {
1825	>	delta = 1;
1826	>	node = new Node<K,V>(h, key, val, null);
1827	>	}
1828	>	} finally {
1829	>	setTabAt(tab, i, node);
1830	>	}
1831	>	}
1832	>	}
1833	>	if (binCount != 0)
1834	>	break;
1835	>	}
1836	>	else if ((fh = f.hash) == MOVED)
1837	>	tab = helpTransfer(tab, f);
1838	>	else {
1839	>	synchronized (f) {
1840	>	if (tabAt(tab, i) == f) {
1841	>	if (fh >= 0) {
1842	>	binCount = 1;
1843	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1844	>	K ek;
1845	>	if (e.hash == h &&
1846	>	((ek = e.key) == key ||
1847	>	(ek != null && key.equals(ek)))) {
1848	>	val = remappingFunction.apply(key, e.val);
1849	>	if (val != null)
1850	>	e.val = val;
1851	>	else {
1852	>	delta = -1;
1853	>	Node<K,V> en = e.next;
1854	>	if (pred != null)
1855	>	pred.next = en;
1856	>	else
1857	>	setTabAt(tab, i, en);
1858	>	}
1859	>	break;
1860	>	}
1861	>	pred = e;
1862	>	if ((e = e.next) == null) {
1863	>	val = remappingFunction.apply(key, null);
1864	>	if (val != null) {
1865	>	delta = 1;
1866	>	pred.next =
1867	>	new Node<K,V>(h, key, val, null);
1868	>	}
1869	>	break;
1870	>	}
1871	>	}
1872	>	}
1873	>	else if (f instanceof TreeBin) {
1874	>	binCount = 1;
1875	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1876	>	TreeNode<K,V> r, p;
1877	>	if ((r = t.root) != null)
1878	>	p = r.findTreeNode(h, key, null);
1879	>	else
1880	>	p = null;
1881	>	V pv = (p == null) ? null : p.val;
1882	>	val = remappingFunction.apply(key, pv);
1883	>	if (val != null) {
1884	>	if (p != null)
1885	>	p.val = val;
1886	>	else {
1887	>	delta = 1;
1888	>	t.putTreeVal(h, key, val);
1889	>	}
1890	>	}
1891	>	else if (p != null) {
1892	>	delta = -1;
1893	>	if (t.removeTreeNode(p))
1894	>	setTabAt(tab, i, untreeify(t.first));
1895	>	}
1896	>	}
1897	>	}
1898	>	}
1899	>	if (binCount != 0) {
1900	>	if (binCount >= TREEIFY_THRESHOLD)
1901	>	treeifyBin(tab, i);
1902	>	break;
1903	>	}
1904	>	}
1905	>	}
1906	>	if (delta != 0)
1907	>	addCount((long)delta, binCount);
1908	>	return val;
1909		}
1910
1911		/**
1912	<	* Returns <tt>true</tt> if this map maps one or more keys to the
1913	<	* specified value. Note: This method requires a full internal
1914	<	* traversal of the hash table, and so is much slower than
1915	<	* method <tt>containsKey</tt>.
1912	>	* If the specified key is not already associated with a
1913	>	* (non-null) value, associates it with the given value.
1914	>	* Otherwise, replaces the value with the results of the given
1915	>	* remapping function, or removes if {@code null}. The entire
1916	>	* method invocation is performed atomically.  Some attempted
1917	>	* update operations on this map by other threads may be blocked
1918	>	* while computation is in progress, so the computation should be
1919	>	* short and simple, and must not attempt to update any other
1920	>	* mappings of this Map.
1921		*
1922	<	* @param value value whose presence in this map is to be tested
1923	<	* @return <tt>true</tt> if this map maps one or more keys to the
1924	<	*         specified value
1925	<	* @throws NullPointerException if the specified value is null
1922	>	* @param key key with which the specified value is to be associated
1923	>	* @param value the value to use if absent
1924	>	* @param remappingFunction the function to recompute a value if present
1925	>	* @return the new value associated with the specified key, or null if none
1926	>	* @throws NullPointerException if the specified key or the
1927	>	*         remappingFunction is null
1928	>	* @throws RuntimeException or Error if the remappingFunction does so,
1929	>	*         in which case the mapping is unchanged
1930		*/
1931	<	public boolean containsValue(Object value) {
1932	<	if (value == null)
1931	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1932	>	if (key == null || value == null || remappingFunction == null)
1933		throw new NullPointerException();
1934	<
1935	<	// See explanation of modCount use above
1936	<
1937	<	final Segment<K,V>[] segments = this.segments;
1938	<	int[] mc = new int[segments.length];
1939	<
1940	<	// Try a few times without locking
1941	<	for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
1942	<	int sum = 0;
1943	<	int mcsum = 0;
1944	<	for (int i = 0; i < segments.length; ++i) {
1945	<	int c = segments[i].count;
1946	<	mcsum += mc[i] = segments[i].modCount;
1947	<	if (segments[i].containsValue(value))
808	<	return true;
1934	>	int h = spread(key.hashCode());
1935	>	V val = null;
1936	>	int delta = 0;
1937	>	int binCount = 0;
1938	>	for (Node<K,V>[] tab = table;;) {
1939	>	Node<K,V> f; int n, i, fh;
1940	>	if (tab == null || (n = tab.length) == 0)
1941	>	tab = initTable();
1942	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1943	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1944	>	delta = 1;
1945	>	val = value;
1946	>	break;
1947	>	}
1948		}
1949	<	boolean cleanSweep = true;
1950	<	if (mcsum != 0) {
1951	<	for (int i = 0; i < segments.length; ++i) {
1952	<	int c = segments[i].count;
1953	<	if (mc[i] != segments[i].modCount) {
1954	<	cleanSweep = false;
1955	<	break;
1949	>	else if ((fh = f.hash) == MOVED)
1950	>	tab = helpTransfer(tab, f);
1951	>	else {
1952	>	synchronized (f) {
1953	>	if (tabAt(tab, i) == f) {
1954	>	if (fh >= 0) {
1955	>	binCount = 1;
1956	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1957	>	K ek;
1958	>	if (e.hash == h &&
1959	>	((ek = e.key) == key ||
1960	>	(ek != null && key.equals(ek)))) {
1961	>	val = remappingFunction.apply(e.val, value);
1962	>	if (val != null)
1963	>	e.val = val;
1964	>	else {
1965	>	delta = -1;
1966	>	Node<K,V> en = e.next;
1967	>	if (pred != null)
1968	>	pred.next = en;
1969	>	else
1970	>	setTabAt(tab, i, en);
1971	>	}
1972	>	break;
1973	>	}
1974	>	pred = e;
1975	>	if ((e = e.next) == null) {
1976	>	delta = 1;
1977	>	val = value;
1978	>	pred.next =
1979	>	new Node<K,V>(h, key, val, null);
1980	>	break;
1981	>	}
1982	>	}
1983	>	}
1984	>	else if (f instanceof TreeBin) {
1985	>	binCount = 2;
1986	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1987	>	TreeNode<K,V> r = t.root;
1988	>	TreeNode<K,V> p = (r == null) ? null :
1989	>	r.findTreeNode(h, key, null);
1990	>	val = (p == null) ? value :
1991	>	remappingFunction.apply(p.val, value);
1992	>	if (val != null) {
1993	>	if (p != null)
1994	>	p.val = val;
1995	>	else {
1996	>	delta = 1;
1997	>	t.putTreeVal(h, key, val);
1998	>	}
1999	>	}
2000	>	else if (p != null) {
2001	>	delta = -1;
2002	>	if (t.removeTreeNode(p))
2003	>	setTabAt(tab, i, untreeify(t.first));
2004	>	}
2005	>	}
2006		}
2007		}
2008	<	}
2009	<	if (cleanSweep)
2010	<	return false;
822	<	}
823	<	// Resort to locking all segments
824	<	for (int i = 0; i < segments.length; ++i)
825	<	segments[i].lock();
826	<	boolean found = false;
827	<	try {
828	<	for (int i = 0; i < segments.length; ++i) {
829	<	if (segments[i].containsValue(value)) {
830	<	found = true;
2008	>	if (binCount != 0) {
2009	>	if (binCount >= TREEIFY_THRESHOLD)
2010	>	treeifyBin(tab, i);
2011		break;
2012		}
2013		}
834	–	} finally {
835	–	for (int i = 0; i < segments.length; ++i)
836	–	segments[i].unlock();
2014		}
2015	<	return found;
2015	>	if (delta != 0)
2016	>	addCount((long)delta, binCount);
2017	>	return val;
2018		}
2019
2020	+	// Hashtable legacy methods
2021	+
2022		/**
2023		* Legacy method testing if some key maps into the specified value
2024	<	* in this table.  This method is identical in functionality to
2025	<	* {@link #containsValue}, and exists solely to ensure
2024	>	* in this table.
2025	>	*
2026	>	* @deprecated This method is identical in functionality to
2027	>	* {@link #containsValue(Object)}, and exists solely to ensure
2028		* full compatibility with class {@link java.util.Hashtable},
2029		* which supported this method prior to introduction of the
2030		* Java Collections framework.
2031	<
2031	>	*
2032		* @param  value a value to search for
2033	<	* @return <tt>true</tt> if and only if some key maps to the
2034	<	*         <tt>value</tt> argument in this table as
2035	<	*         determined by the <tt>equals</tt> method;
2036	<	*         <tt>false</tt> otherwise
2033	>	* @return {@code true} if and only if some key maps to the
2034	>	*         {@code value} argument in this table as
2035	>	*         determined by the {@code equals} method;
2036	>	*         {@code false} otherwise
2037		* @throws NullPointerException if the specified value is null
2038		*/
2039	+	@Deprecated
2040		public boolean contains(Object value) {
2041		return containsValue(value);
2042		}
2043
2044		/**
2045	<	* Maps the specified key to the specified value in this table.
862	<	* Neither the key nor the value can be null.
863	<	*
864	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
865	<	* with a key that is equal to the original key.
2045	>	* Returns an enumeration of the keys in this table.
2046		*
2047	<	* @param key key with which the specified value is to be associated
2048	<	* @param value value to be associated with the specified key
869	<	* @return the previous value associated with <tt>key</tt>, or
870	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
871	<	* @throws NullPointerException if the specified key or value is null
2047	>	* @return an enumeration of the keys in this table
2048	>	* @see #keySet()
2049		*/
2050	<	public V put(K key, V value) {
2051	<	if (value == null)
2052	<	throw new NullPointerException();
2053	<	int hash = hash(key);
877	<	return segmentFor(hash).put(key, hash, value, false);
2050	>	public Enumeration<K> keys() {
2051	>	Node<K,V>[] t;
2052	>	int f = (t = table) == null ? 0 : t.length;
2053	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2054		}
2055
2056		/**
2057	<	* {@inheritDoc}
2057	>	* Returns an enumeration of the values in this table.
2058		*
2059	<	* @return the previous value associated with the specified key,
2060	<	*         or <tt>null</tt> if there was no mapping for the key
885	<	* @throws NullPointerException if the specified key or value is null
2059	>	* @return an enumeration of the values in this table
2060	>	* @see #values()
2061		*/
2062	<	public V putIfAbsent(K key, V value) {
2063	<	if (value == null)
2064	<	throw new NullPointerException();
2065	<	int hash = hash(key);
891	<	return segmentFor(hash).put(key, hash, value, true);
2062	>	public Enumeration<V> elements() {
2063	>	Node<K,V>[] t;
2064	>	int f = (t = table) == null ? 0 : t.length;
2065	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2066		}
2067
2068	+	// ConcurrentHashMap-only methods
2069	+
2070		/**
2071	<	* Copies all of the mappings from the specified map to this one.
2072	<	* These mappings replace any mappings that this map had for any of the
2073	<	* keys currently in the specified map.
2071	>	* Returns the number of mappings. This method should be used
2072	>	* instead of {@link #size} because a ConcurrentHashMap may
2073	>	* contain more mappings than can be represented as an int. The
2074	>	* value returned is an estimate; the actual count may differ if
2075	>	* there are concurrent insertions or removals.
2076		*
2077	<	* @param m mappings to be stored in this map
2077	>	* @return the number of mappings
2078	>	* @since 1.8
2079		*/
2080	<	public void putAll(Map<? extends K, ? extends V> m) {
2081	<	for (Iterator<? extends Map.Entry<? extends K, ? extends V>> it = (Iterator<? extends Map.Entry<? extends K, ? extends V>>) m.entrySet().iterator(); it.hasNext(); ) {
2082	<	Entry<? extends K, ? extends V> e = it.next();
904	<	put(e.getKey(), e.getValue());
905	<	}
2080	>	public long mappingCount() {
2081	>	long n = sumCount();
2082	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2083		}
2084
2085		/**
2086	<	* Removes the key (and its corresponding value) from this map.
2087	<	* This method does nothing if the key is not in the map.
2086	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2087	>	* from the given type to {@code Boolean.TRUE}.
2088		*
2089	<	* @param  key the key that needs to be removed
2090	<	* @return the previous value associated with <tt>key</tt>, or
2091	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>.
2092	<	* @throws NullPointerException if the specified key is null
2093	<	*/
2094	<	public V remove(Object key) {
2095	<	int hash = hash(key);
919	<	return segmentFor(hash).remove(key, hash, null);
2089	>	* @param <K> the element type of the returned set
2090	>	* @return the new set
2091	>	* @since 1.8
2092	>	*/
2093	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2094	>	return new KeySetView<K,Boolean>
2095	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2096		}
2097
2098		/**
2099	<	* {@inheritDoc}
2099	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2100	>	* from the given type to {@code Boolean.TRUE}.
2101		*
2102	<	* @throws NullPointerException if the specified key is null
2102	>	* @param initialCapacity The implementation performs internal
2103	>	* sizing to accommodate this many elements.
2104	>	* @param <K> the element type of the returned set
2105	>	* @return the new set
2106	>	* @throws IllegalArgumentException if the initial capacity of
2107	>	* elements is negative
2108	>	* @since 1.8
2109		*/
2110	<	public boolean remove(Object key, Object value) {
2111	<	if (value == null)
2112	<	return false;
930	<	int hash = hash(key);
931	<	return segmentFor(hash).remove(key, hash, value) != null;
2110	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2111	>	return new KeySetView<K,Boolean>
2112	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2113		}
2114
2115		/**
2116	<	* {@inheritDoc}
2116	>	* Returns a {@link Set} view of the keys in this map, using the
2117	>	* given common mapped value for any additions (i.e., {@link
2118	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2119	>	* This is of course only appropriate if it is acceptable to use
2120	>	* the same value for all additions from this view.
2121		*
2122	<	* @throws NullPointerException if any of the arguments are null
2122	>	* @param mappedValue the mapped value to use for any additions
2123	>	* @return the set view
2124	>	* @throws NullPointerException if the mappedValue is null
2125		*/
2126	<	public boolean replace(K key, V oldValue, V newValue) {
2127	<	if (oldValue == null || newValue == null)
2126	>	public KeySetView<K,V> keySet(V mappedValue) {
2127	>	if (mappedValue == null)
2128		throw new NullPointerException();
2129	<	int hash = hash(key);
943	<	return segmentFor(hash).replace(key, hash, oldValue, newValue);
2129	>	return new KeySetView<K,V>(this, mappedValue);
2130		}
2131
2132	+	/* ---------------- Special Nodes -------------- */
2133	+
2134		/**
2135	<	* {@inheritDoc}
948	<	*
949	<	* @return the previous value associated with the specified key,
950	<	*         or <tt>null</tt> if there was no mapping for the key
951	<	* @throws NullPointerException if the specified key or value is null
2135	>	* A node inserted at head of bins during transfer operations.
2136		*/
2137	<	public V replace(K key, V value) {
2138	<	if (value == null)
2139	<	throw new NullPointerException();
2140	<	int hash = hash(key);
2141	<	return segmentFor(hash).replace(key, hash, value);
2137	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2138	>	final Node<K,V>[] nextTable;
2139	>	ForwardingNode(Node<K,V>[] tab) {
2140	>	super(MOVED, null, null, null);
2141	>	this.nextTable = tab;
2142	>	}
2143	>
2144	>	Node<K,V> find(int h, Object k) {
2145	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2146	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2147	>	Node<K,V> e; int n;
2148	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2149	>	(e = tabAt(tab, (n - 1) & h)) == null)
2150	>	return null;
2151	>	for (;;) {
2152	>	int eh; K ek;
2153	>	if ((eh = e.hash) == h &&
2154	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2155	>	return e;
2156	>	if (eh < 0) {
2157	>	if (e instanceof ForwardingNode) {
2158	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2159	>	continue outer;
2160	>	}
2161	>	else
2162	>	return e.find(h, k);
2163	>	}
2164	>	if ((e = e.next) == null)
2165	>	return null;
2166	>	}
2167	>	}
2168	>	}
2169		}
2170
2171		/**
2172	<	* Removes all of the mappings from this map.
2172	>	* A place-holder node used in computeIfAbsent and compute
2173		*/
2174	<	public void clear() {
2175	<	for (int i = 0; i < segments.length; ++i)
2176	<	segments[i].clear();
2174	>	static final class ReservationNode<K,V> extends Node<K,V> {
2175	>	ReservationNode() {
2176	>	super(RESERVED, null, null, null);
2177	>	}
2178	>
2179	>	Node<K,V> find(int h, Object k) {
2180	>	return null;
2181	>	}
2182		}
2183
2184	+	/* ---------------- Table Initialization and Resizing -------------- */
2185	+
2186		/**
2187	<	* Returns a {@link Set} view of the keys contained in this map.
2188	<	* The set is backed by the map, so changes to the map are
2189	<	* reflected in the set, and vice-versa.  The set supports element
2190	<	* removal, which removes the corresponding mapping from this map,
2191	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
974	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
975	<	* operations.  It does not support the <tt>add</tt> or
976	<	* <tt>addAll</tt> operations.
977	<	*
978	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
979	<	* that will never throw {@link ConcurrentModificationException},
980	<	* and guarantees to traverse elements as they existed upon
981	<	* construction of the iterator, and may (but is not guaranteed to)
982	<	* reflect any modifications subsequent to construction.
983	<	*/
984	<	public Set<K> keySet() {
985	<	Set<K> ks = keySet;
986	<	return (ks != null) ? ks : (keySet = new KeySet());
2187	>	* Returns the stamp bits for resizing a table of size n.
2188	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2189	>	*/
2190	>	static final int resizeStamp(int n) {
2191	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2192		}
2193
2194		/**
2195	<	* Returns a {@link Collection} view of the values contained in this map.
991	<	* The collection is backed by the map, so changes to the map are
992	<	* reflected in the collection, and vice-versa.  The collection
993	<	* supports element removal, which removes the corresponding
994	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
995	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
996	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
997	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
998	<	*
999	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1000	<	* that will never throw {@link ConcurrentModificationException},
1001	<	* and guarantees to traverse elements as they existed upon
1002	<	* construction of the iterator, and may (but is not guaranteed to)
1003	<	* reflect any modifications subsequent to construction.
2195	>	* Initializes table, using the size recorded in sizeCtl.
2196		*/
2197	<	public Collection<V> values() {
2198	<	Collection<V> vs = values;
2199	<	return (vs != null) ? vs : (values = new Values());
2197	>	private final Node<K,V>[] initTable() {
2198	>	Node<K,V>[] tab; int sc;
2199	>	while ((tab = table) == null || tab.length == 0) {
2200	>	if ((sc = sizeCtl) < 0)
2201	>	Thread.yield(); // lost initialization race; just spin
2202	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2203	>	try {
2204	>	if ((tab = table) == null || tab.length == 0) {
2205	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2206	>	@SuppressWarnings("unchecked")
2207	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2208	>	table = tab = nt;
2209	>	sc = n - (n >>> 2);
2210	>	}
2211	>	} finally {
2212	>	sizeCtl = sc;
2213	>	}
2214	>	break;
2215	>	}
2216	>	}
2217	>	return tab;
2218		}
2219
2220		/**
2221	<	* Returns a {@link Set} view of the mappings contained in this map.
2222	<	* The set is backed by the map, so changes to the map are
2223	<	* reflected in the set, and vice-versa.  The set supports element
2224	<	* removal, which removes the corresponding mapping from the map,
2225	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2226	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2227	<	* operations.  It does not support the <tt>add</tt> or
2228	<	* <tt>addAll</tt> operations.
1019	<	*
1020	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1021	<	* that will never throw {@link ConcurrentModificationException},
1022	<	* and guarantees to traverse elements as they existed upon
1023	<	* construction of the iterator, and may (but is not guaranteed to)
1024	<	* reflect any modifications subsequent to construction.
2221	>	* Adds to count, and if table is too small and not already
2222	>	* resizing, initiates transfer. If already resizing, helps
2223	>	* perform transfer if work is available.  Rechecks occupancy
2224	>	* after a transfer to see if another resize is already needed
2225	>	* because resizings are lagging additions.
2226	>	*
2227	>	* @param x the count to add
2228	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2229		*/
2230	<	public Set<Map.Entry<K,V>> entrySet() {
2231	<	Set<Map.Entry<K,V>> es = entrySet;
2232	<	return (es != null) ? es : (entrySet = new EntrySet());
2230	>	private final void addCount(long x, int check) {
2231	>	CounterCell[] as; long b, s;
2232	>	if ((as = counterCells) != null ||
2233	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2234	>	CounterCell a; long v; int m;
2235	>	boolean uncontended = true;
2236	>	if (as == null || (m = as.length - 1) < 0 ||
2237	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2238	>	!(uncontended =
2239	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2240	>	fullAddCount(x, uncontended);
2241	>	return;
2242	>	}
2243	>	if (check <= 1)
2244	>	return;
2245	>	s = sumCount();
2246	>	}
2247	>	if (check >= 0) {
2248	>	Node<K,V>[] tab, nt; int n, sc;
2249	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2250	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2251	>	int rs = resizeStamp(n);
2252	>	if (sc < 0) {
2253	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2254	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2255	>	transferIndex <= 0)
2256	>	break;
2257	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2258	>	transfer(tab, nt);
2259	>	}
2260	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2261	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2262	>	transfer(tab, null);
2263	>	s = sumCount();
2264	>	}
2265	>	}
2266		}
2267
2268		/**
2269	<	* Returns an enumeration of the keys in this table.
1033	<	*
1034	<	* @return an enumeration of the keys in this table
1035	<	* @see #keySet
2269	>	* Helps transfer if a resize is in progress.
2270		*/
2271	<	public Enumeration<K> keys() {
2272	<	return new KeyIterator();
2271	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2272	>	Node<K,V>[] nextTab; int sc;
2273	>	if (tab != null && (f instanceof ForwardingNode) &&
2274	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2275	>	int rs = resizeStamp(tab.length);
2276	>	while (nextTab == nextTable && table == tab &&
2277	>	(sc = sizeCtl) < 0) {
2278	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2279	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2280	>	break;
2281	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2282	>	transfer(tab, nextTab);
2283	>	break;
2284	>	}
2285	>	}
2286	>	return nextTab;
2287	>	}
2288	>	return table;
2289		}
2290
2291		/**
2292	<	* Returns an enumeration of the values in this table.
2292	>	* Tries to presize table to accommodate the given number of elements.
2293		*
2294	<	* @return an enumeration of the values in this table
1045	<	* @see #values
2294	>	* @param size number of elements (doesn't need to be perfectly accurate)
2295		*/
2296	<	public Enumeration<V> elements() {
2297	<	return new ValueIterator();
2296	>	private final void tryPresize(int size) {
2297	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2298	>	tableSizeFor(size + (size >>> 1) + 1);
2299	>	int sc;
2300	>	while ((sc = sizeCtl) >= 0) {
2301	>	Node<K,V>[] tab = table; int n;
2302	>	if (tab == null || (n = tab.length) == 0) {
2303	>	n = (sc > c) ? sc : c;
2304	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2305	>	try {
2306	>	if (table == tab) {
2307	>	@SuppressWarnings("unchecked")
2308	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2309	>	table = nt;
2310	>	sc = n - (n >>> 2);
2311	>	}
2312	>	} finally {
2313	>	sizeCtl = sc;
2314	>	}
2315	>	}
2316	>	}
2317	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2318	>	break;
2319	>	else if (tab == table) {
2320	>	int rs = resizeStamp(n);
2321	>	if (sc < 0) {
2322	>	Node<K,V>[] nt;
2323	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2324	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2325	>	transferIndex <= 0)
2326	>	break;
2327	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2328	>	transfer(tab, nt);
2329	>	}
2330	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2331	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2332	>	transfer(tab, null);
2333	>	}
2334	>	}
2335		}
2336
2337	<	/* ---------------- Iterator Support -------------- */
2337	>	/**
2338	>	* Moves and/or copies the nodes in each bin to new table. See
2339	>	* above for explanation.
2340	>	*/
2341	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2342	>	int n = tab.length, stride;
2343	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2344	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2345	>	if (nextTab == null) {            // initiating
2346	>	try {
2347	>	@SuppressWarnings("unchecked")
2348	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2349	>	nextTab = nt;
2350	>	} catch (Throwable ex) {      // try to cope with OOME
2351	>	sizeCtl = Integer.MAX_VALUE;
2352	>	return;
2353	>	}
2354	>	nextTable = nextTab;
2355	>	transferIndex = n;
2356	>	}
2357	>	int nextn = nextTab.length;
2358	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2359	>	boolean advance = true;
2360	>	boolean finishing = false; // to ensure sweep before committing nextTab
2361	>	for (int i = 0, bound = 0;;) {
2362	>	Node<K,V> f; int fh;
2363	>	while (advance) {
2364	>	int nextIndex, nextBound;
2365	>	if (--i >= bound || finishing)
2366	>	advance = false;
2367	>	else if ((nextIndex = transferIndex) <= 0) {
2368	>	i = -1;
2369	>	advance = false;
2370	>	}
2371	>	else if (U.compareAndSwapInt
2372	>	(this, TRANSFERINDEX, nextIndex,
2373	>	nextBound = (nextIndex > stride ?
2374	>	nextIndex - stride : 0))) {
2375	>	bound = nextBound;
2376	>	i = nextIndex - 1;
2377	>	advance = false;
2378	>	}
2379	>	}
2380	>	if (i < 0 || i >= n || i + n >= nextn) {
2381	>	int sc;
2382	>	if (finishing) {
2383	>	nextTable = null;
2384	>	table = nextTab;
2385	>	sizeCtl = (n << 1) - (n >>> 1);
2386	>	return;
2387	>	}
2388	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2389	>	if ((sc - 2) != resizeStamp(n))
2390	>	return;
2391	>	finishing = advance = true;
2392	>	i = n; // recheck before commit
2393	>	}
2394	>	}
2395	>	else if ((f = tabAt(tab, i)) == null)
2396	>	advance = casTabAt(tab, i, null, fwd);
2397	>	else if ((fh = f.hash) == MOVED)
2398	>	advance = true; // already processed
2399	>	else {
2400	>	synchronized (f) {
2401	>	if (tabAt(tab, i) == f) {
2402	>	Node<K,V> ln, hn;
2403	>	if (fh >= 0) {
2404	>	int runBit = fh & n;
2405	>	Node<K,V> lastRun = f;
2406	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2407	>	int b = p.hash & n;
2408	>	if (b != runBit) {
2409	>	runBit = b;
2410	>	lastRun = p;
2411	>	}
2412	>	}
2413	>	if (runBit == 0) {
2414	>	ln = lastRun;
2415	>	hn = null;
2416	>	}
2417	>	else {
2418	>	hn = lastRun;
2419	>	ln = null;
2420	>	}
2421	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2422	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2423	>	if ((ph & n) == 0)
2424	>	ln = new Node<K,V>(ph, pk, pv, ln);
2425	>	else
2426	>	hn = new Node<K,V>(ph, pk, pv, hn);
2427	>	}
2428	>	setTabAt(nextTab, i, ln);
2429	>	setTabAt(nextTab, i + n, hn);
2430	>	setTabAt(tab, i, fwd);
2431	>	advance = true;
2432	>	}
2433	>	else if (f instanceof TreeBin) {
2434	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2435	>	TreeNode<K,V> lo = null, loTail = null;
2436	>	TreeNode<K,V> hi = null, hiTail = null;
2437	>	int lc = 0, hc = 0;
2438	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2439	>	int h = e.hash;
2440	>	TreeNode<K,V> p = new TreeNode<K,V>
2441	>	(h, e.key, e.val, null, null);
2442	>	if ((h & n) == 0) {
2443	>	if ((p.prev = loTail) == null)
2444	>	lo = p;
2445	>	else
2446	>	loTail.next = p;
2447	>	loTail = p;
2448	>	++lc;
2449	>	}
2450	>	else {
2451	>	if ((p.prev = hiTail) == null)
2452	>	hi = p;
2453	>	else
2454	>	hiTail.next = p;
2455	>	hiTail = p;
2456	>	++hc;
2457	>	}
2458	>	}
2459	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2460	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2461	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2462	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2463	>	setTabAt(nextTab, i, ln);
2464	>	setTabAt(nextTab, i + n, hn);
2465	>	setTabAt(tab, i, fwd);
2466	>	advance = true;
2467	>	}
2468	>	}
2469	>	}
2470	>	}
2471	>	}
2472	>	}
2473
2474	<	abstract class HashIterator {
1054	<	int nextSegmentIndex;
1055	<	int nextTableIndex;
1056	<	HashEntry<K,V>[] currentTable;
1057	<	HashEntry<K, V> nextEntry;
1058	<	HashEntry<K, V> lastReturned;
2474	>	/* ---------------- Counter support -------------- */
2475
2476	<	HashIterator() {
2477	<	nextSegmentIndex = segments.length - 1;
2478	<	nextTableIndex = -1;
2479	<	advance();
2476	>	/**
2477	>	* A padded cell for distributing counts.  Adapted from LongAdder
2478	>	* and Striped64.  See their internal docs for explanation.
2479	>	*/
2480	>	@sun.misc.Contended static final class CounterCell {
2481	>	volatile long value;
2482	>	CounterCell(long x) { value = x; }
2483	>	}
2484	>
2485	>	final long sumCount() {
2486	>	CounterCell[] as = counterCells; CounterCell a;
2487	>	long sum = baseCount;
2488	>	if (as != null) {
2489	>	for (int i = 0; i < as.length; ++i) {
2490	>	if ((a = as[i]) != null)
2491	>	sum += a.value;
2492	>	}
2493		}
2494	+	return sum;
2495	+	}
2496
2497	<	public boolean hasMoreElements() { return hasNext(); }
2497	>	// See LongAdder version for explanation
2498	>	private final void fullAddCount(long x, boolean wasUncontended) {
2499	>	int h;
2500	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2501	>	ThreadLocalRandom.localInit();      // force initialization
2502	>	h = ThreadLocalRandom.getProbe();
2503	>	wasUncontended = true;
2504	>	}
2505	>	boolean collide = false;                // True if last slot nonempty
2506	>	for (;;) {
2507	>	CounterCell[] as; CounterCell a; int n; long v;
2508	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2509	>	if ((a = as[(n - 1) & h]) == null) {
2510	>	if (cellsBusy == 0) {            // Try to attach new Cell
2511	>	CounterCell r = new CounterCell(x); // Optimistic create
2512	>	if (cellsBusy == 0 &&
2513	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2514	>	boolean created = false;
2515	>	try {               // Recheck under lock
2516	>	CounterCell[] rs; int m, j;
2517	>	if ((rs = counterCells) != null &&
2518	>	(m = rs.length) > 0 &&
2519	>	rs[j = (m - 1) & h] == null) {
2520	>	rs[j] = r;
2521	>	created = true;
2522	>	}
2523	>	} finally {
2524	>	cellsBusy = 0;
2525	>	}
2526	>	if (created)
2527	>	break;
2528	>	continue;           // Slot is now non-empty
2529	>	}
2530	>	}
2531	>	collide = false;
2532	>	}
2533	>	else if (!wasUncontended)       // CAS already known to fail
2534	>	wasUncontended = true;      // Continue after rehash
2535	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2536	>	break;
2537	>	else if (counterCells != as || n >= NCPU)
2538	>	collide = false;            // At max size or stale
2539	>	else if (!collide)
2540	>	collide = true;
2541	>	else if (cellsBusy == 0 &&
2542	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2543	>	try {
2544	>	if (counterCells == as) {// Expand table unless stale
2545	>	CounterCell[] rs = new CounterCell[n << 1];
2546	>	for (int i = 0; i < n; ++i)
2547	>	rs[i] = as[i];
2548	>	counterCells = rs;
2549	>	}
2550	>	} finally {
2551	>	cellsBusy = 0;
2552	>	}
2553	>	collide = false;
2554	>	continue;                   // Retry with expanded table
2555	>	}
2556	>	h = ThreadLocalRandom.advanceProbe(h);
2557	>	}
2558	>	else if (cellsBusy == 0 && counterCells == as &&
2559	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2560	>	boolean init = false;
2561	>	try {                           // Initialize table
2562	>	if (counterCells == as) {
2563	>	CounterCell[] rs = new CounterCell[2];
2564	>	rs[h & 1] = new CounterCell(x);
2565	>	counterCells = rs;
2566	>	init = true;
2567	>	}
2568	>	} finally {
2569	>	cellsBusy = 0;
2570	>	}
2571	>	if (init)
2572	>	break;
2573	>	}
2574	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2575	>	break;                          // Fall back on using base
2576	>	}
2577	>	}
2578
2579	<	final void advance() {
1069	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
1070	<	return;
2579	>	/* ---------------- Conversion from/to TreeBins -------------- */
2580
2581	<	while (nextTableIndex >= 0) {
2582	<	if ( (nextEntry = currentTable[nextTableIndex--]) != null)
2583	<	return;
2581	>	/**
2582	>	* Replaces all linked nodes in bin at given index unless table is
2583	>	* too small, in which case resizes instead.
2584	>	*/
2585	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2586	>	Node<K,V> b; int n, sc;
2587	>	if (tab != null) {
2588	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2589	>	tryPresize(n << 1);
2590	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2591	>	synchronized (b) {
2592	>	if (tabAt(tab, index) == b) {
2593	>	TreeNode<K,V> hd = null, tl = null;
2594	>	for (Node<K,V> e = b; e != null; e = e.next) {
2595	>	TreeNode<K,V> p =
2596	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2597	>	null, null);
2598	>	if ((p.prev = tl) == null)
2599	>	hd = p;
2600	>	else
2601	>	tl.next = p;
2602	>	tl = p;
2603	>	}
2604	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2605	>	}
2606	>	}
2607	>	}
2608	>	}
2609	>	}
2610	>
2611	>	/**
2612	>	* Returns a list on non-TreeNodes replacing those in given list.
2613	>	*/
2614	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2615	>	Node<K,V> hd = null, tl = null;
2616	>	for (Node<K,V> q = b; q != null; q = q.next) {
2617	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2618	>	if (tl == null)
2619	>	hd = p;
2620	>	else
2621	>	tl.next = p;
2622	>	tl = p;
2623	>	}
2624	>	return hd;
2625	>	}
2626	>
2627	>	/* ---------------- TreeNodes -------------- */
2628	>
2629	>	/**
2630	>	* Nodes for use in TreeBins
2631	>	*/
2632	>	static final class TreeNode<K,V> extends Node<K,V> {
2633	>	TreeNode<K,V> parent;  // red-black tree links
2634	>	TreeNode<K,V> left;
2635	>	TreeNode<K,V> right;
2636	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2637	>	boolean red;
2638	>
2639	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2640	>	TreeNode<K,V> parent) {
2641	>	super(hash, key, val, next);
2642	>	this.parent = parent;
2643	>	}
2644	>
2645	>	Node<K,V> find(int h, Object k) {
2646	>	return findTreeNode(h, k, null);
2647	>	}
2648	>
2649	>	/**
2650	>	* Returns the TreeNode (or null if not found) for the given key
2651	>	* starting at given root.
2652	>	*/
2653	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2654	>	if (k != null) {
2655	>	TreeNode<K,V> p = this;
2656	>	do  {
2657	>	int ph, dir; K pk; TreeNode<K,V> q;
2658	>	TreeNode<K,V> pl = p.left, pr = p.right;
2659	>	if ((ph = p.hash) > h)
2660	>	p = pl;
2661	>	else if (ph < h)
2662	>	p = pr;
2663	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2664	>	return p;
2665	>	else if (pl == null)
2666	>	p = pr;
2667	>	else if (pr == null)
2668	>	p = pl;
2669	>	else if ((kc != null ||
2670	>	(kc = comparableClassFor(k)) != null) &&
2671	>	(dir = compareComparables(kc, k, pk)) != 0)
2672	>	p = (dir < 0) ? pl : pr;
2673	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2674	>	return q;
2675	>	else
2676	>	p = pl;
2677	>	} while (p != null);
2678		}
2679	+	return null;
2680	+	}
2681	+	}
2682
2683	<	while (nextSegmentIndex >= 0) {
2684	<	Segment<K,V> seg = segments[nextSegmentIndex--];
2685	<	if (seg.count != 0) {
2686	<	currentTable = seg.table;
2687	<	for (int j = currentTable.length - 1; j >= 0; --j) {
2688	<	if ( (nextEntry = currentTable[j]) != null) {
2689	<	nextTableIndex = j - 1;
2690	<	return;
2683	>	/* ---------------- TreeBins -------------- */
2684	>
2685	>	/**
2686	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2687	>	* keys or values, but instead point to list of TreeNodes and
2688	>	* their root. They also maintain a parasitic read-write lock
2689	>	* forcing writers (who hold bin lock) to wait for readers (who do
2690	>	* not) to complete before tree restructuring operations.
2691	>	*/
2692	>	static final class TreeBin<K,V> extends Node<K,V> {
2693	>	TreeNode<K,V> root;
2694	>	volatile TreeNode<K,V> first;
2695	>	volatile Thread waiter;
2696	>	volatile int lockState;
2697	>	// values for lockState
2698	>	static final int WRITER = 1; // set while holding write lock
2699	>	static final int WAITER = 2; // set when waiting for write lock
2700	>	static final int READER = 4; // increment value for setting read lock
2701	>
2702	>	/**
2703	>	* Tie-breaking utility for ordering insertions when equal
2704	>	* hashCodes and non-comparable. We don't require a total
2705	>	* order, just a consistent insertion rule to maintain
2706	>	* equivalence across rebalancings. Tie-breaking further than
2707	>	* necessary simplifies testing a bit.
2708	>	*/
2709	>	static int tieBreakOrder(Object a, Object b) {
2710	>	int d;
2711	>	if (a == null || b == null ||
2712	>	(d = a.getClass().getName().
2713	>	compareTo(b.getClass().getName())) == 0)
2714	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2715	>	-1 : 1);
2716	>	return d;
2717	>	}
2718	>
2719	>	/**
2720	>	* Creates bin with initial set of nodes headed by b.
2721	>	*/
2722	>	TreeBin(TreeNode<K,V> b) {
2723	>	super(TREEBIN, null, null, null);
2724	>	this.first = b;
2725	>	TreeNode<K,V> r = null;
2726	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2727	>	next = (TreeNode<K,V>)x.next;
2728	>	x.left = x.right = null;
2729	>	if (r == null) {
2730	>	x.parent = null;
2731	>	x.red = false;
2732	>	r = x;
2733	>	}
2734	>	else {
2735	>	K k = x.key;
2736	>	int h = x.hash;
2737	>	Class<?> kc = null;
2738	>	for (TreeNode<K,V> p = r;;) {
2739	>	int dir, ph;
2740	>	K pk = p.key;
2741	>	if ((ph = p.hash) > h)
2742	>	dir = -1;
2743	>	else if (ph < h)
2744	>	dir = 1;
2745	>	else if ((kc == null &&
2746	>	(kc = comparableClassFor(k)) == null) ||
2747	>	(dir = compareComparables(kc, k, pk)) == 0)
2748	>	dir = tieBreakOrder(k, pk);
2749	>	TreeNode<K,V> xp = p;
2750	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2751	>	x.parent = xp;
2752	>	if (dir <= 0)
2753	>	xp.left = x;
2754	>	else
2755	>	xp.right = x;
2756	>	r = balanceInsertion(r, x);
2757	>	break;
2758		}
2759		}
2760		}
2761		}
2762	+	this.root = r;
2763	+	assert checkInvariants(root);
2764		}
2765
2766	<	public boolean hasNext() { return nextEntry != null; }
2766	>	/**
2767	>	* Acquires write lock for tree restructuring.
2768	>	*/
2769	>	private final void lockRoot() {
2770	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2771	>	contendedLock(); // offload to separate method
2772	>	}
2773
2774	<	HashEntry<K,V> nextEntry() {
2775	<	if (nextEntry == null)
2776	<	throw new NoSuchElementException();
2777	<	lastReturned = nextEntry;
2774	>	/**
2775	>	* Releases write lock for tree restructuring.
2776	>	*/
2777	>	private final void unlockRoot() {
2778	>	lockState = 0;
2779	>	}
2780	>
2781	>	/**
2782	>	* Possibly blocks awaiting root lock.
2783	>	*/
2784	>	private final void contendedLock() {
2785	>	boolean waiting = false;
2786	>	for (int s;;) {
2787	>	if (((s = lockState) & ~WAITER) == 0) {
2788	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2789	>	if (waiting)
2790	>	waiter = null;
2791	>	return;
2792	>	}
2793	>	}
2794	>	else if ((s & WAITER) == 0) {
2795	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2796	>	waiting = true;
2797	>	waiter = Thread.currentThread();
2798	>	}
2799	>	}
2800	>	else if (waiting)
2801	>	LockSupport.park(this);
2802	>	}
2803	>	}
2804	>
2805	>	/**
2806	>	* Returns matching node or null if none. Tries to search
2807	>	* using tree comparisons from root, but continues linear
2808	>	* search when lock not available.
2809	>	*/
2810	>	final Node<K,V> find(int h, Object k) {
2811	>	if (k != null) {
2812	>	for (Node<K,V> e = first; e != null; e = e.next) {
2813	>	int s; K ek;
2814	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2815	>	if (e.hash == h &&
2816	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2817	>	return e;
2818	>	}
2819	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2820	>	s + READER)) {
2821	>	TreeNode<K,V> r, p;
2822	>	try {
2823	>	p = ((r = root) == null ? null :
2824	>	r.findTreeNode(h, k, null));
2825	>	} finally {
2826	>	Thread w;
2827	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2828	>	(READER|WAITER) && (w = waiter) != null)
2829	>	LockSupport.unpark(w);
2830	>	}
2831	>	return p;
2832	>	}
2833	>	}
2834	>	}
2835	>	return null;
2836	>	}
2837	>
2838	>	/**
2839	>	* Finds or adds a node.
2840	>	* @return null if added
2841	>	*/
2842	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2843	>	Class<?> kc = null;
2844	>	boolean searched = false;
2845	>	for (TreeNode<K,V> p = root;;) {
2846	>	int dir, ph; K pk;
2847	>	if (p == null) {
2848	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2849	>	break;
2850	>	}
2851	>	else if ((ph = p.hash) > h)
2852	>	dir = -1;
2853	>	else if (ph < h)
2854	>	dir = 1;
2855	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2856	>	return p;
2857	>	else if ((kc == null &&
2858	>	(kc = comparableClassFor(k)) == null) ||
2859	>	(dir = compareComparables(kc, k, pk)) == 0) {
2860	>	if (!searched) {
2861	>	TreeNode<K,V> q, ch;
2862	>	searched = true;
2863	>	if (((ch = p.left) != null &&
2864	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2865	>	((ch = p.right) != null &&
2866	>	(q = ch.findTreeNode(h, k, kc)) != null))
2867	>	return q;
2868	>	}
2869	>	dir = tieBreakOrder(k, pk);
2870	>	}
2871	>
2872	>	TreeNode<K,V> xp = p;
2873	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2874	>	TreeNode<K,V> x, f = first;
2875	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2876	>	if (f != null)
2877	>	f.prev = x;
2878	>	if (dir <= 0)
2879	>	xp.left = x;
2880	>	else
2881	>	xp.right = x;
2882	>	if (!xp.red)
2883	>	x.red = true;
2884	>	else {
2885	>	lockRoot();
2886	>	try {
2887	>	root = balanceInsertion(root, x);
2888	>	} finally {
2889	>	unlockRoot();
2890	>	}
2891	>	}
2892	>	break;
2893	>	}
2894	>	}
2895	>	assert checkInvariants(root);
2896	>	return null;
2897	>	}
2898	>
2899	>	/**
2900	>	* Removes the given node, that must be present before this
2901	>	* call.  This is messier than typical red-black deletion code
2902	>	* because we cannot swap the contents of an interior node
2903	>	* with a leaf successor that is pinned by "next" pointers
2904	>	* that are accessible independently of lock. So instead we
2905	>	* swap the tree linkages.
2906	>	*
2907	>	* @return true if now too small, so should be untreeified
2908	>	*/
2909	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2910	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2911	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2912	>	TreeNode<K,V> r, rl;
2913	>	if (pred == null)
2914	>	first = next;
2915	>	else
2916	>	pred.next = next;
2917	>	if (next != null)
2918	>	next.prev = pred;
2919	>	if (first == null) {
2920	>	root = null;
2921	>	return true;
2922	>	}
2923	>	if ((r = root) == null || r.right == null || // too small
2924	>	(rl = r.left) == null || rl.left == null)
2925	>	return true;
2926	>	lockRoot();
2927	>	try {
2928	>	TreeNode<K,V> replacement;
2929	>	TreeNode<K,V> pl = p.left;
2930	>	TreeNode<K,V> pr = p.right;
2931	>	if (pl != null && pr != null) {
2932	>	TreeNode<K,V> s = pr, sl;
2933	>	while ((sl = s.left) != null) // find successor
2934	>	s = sl;
2935	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2936	>	TreeNode<K,V> sr = s.right;
2937	>	TreeNode<K,V> pp = p.parent;
2938	>	if (s == pr) { // p was s's direct parent
2939	>	p.parent = s;
2940	>	s.right = p;
2941	>	}
2942	>	else {
2943	>	TreeNode<K,V> sp = s.parent;
2944	>	if ((p.parent = sp) != null) {
2945	>	if (s == sp.left)
2946	>	sp.left = p;
2947	>	else
2948	>	sp.right = p;
2949	>	}
2950	>	if ((s.right = pr) != null)
2951	>	pr.parent = s;
2952	>	}
2953	>	p.left = null;
2954	>	if ((p.right = sr) != null)
2955	>	sr.parent = p;
2956	>	if ((s.left = pl) != null)
2957	>	pl.parent = s;
2958	>	if ((s.parent = pp) == null)
2959	>	r = s;
2960	>	else if (p == pp.left)
2961	>	pp.left = s;
2962	>	else
2963	>	pp.right = s;
2964	>	if (sr != null)
2965	>	replacement = sr;
2966	>	else
2967	>	replacement = p;
2968	>	}
2969	>	else if (pl != null)
2970	>	replacement = pl;
2971	>	else if (pr != null)
2972	>	replacement = pr;
2973	>	else
2974	>	replacement = p;
2975	>	if (replacement != p) {
2976	>	TreeNode<K,V> pp = replacement.parent = p.parent;
2977	>	if (pp == null)
2978	>	r = replacement;
2979	>	else if (p == pp.left)
2980	>	pp.left = replacement;
2981	>	else
2982	>	pp.right = replacement;
2983	>	p.left = p.right = p.parent = null;
2984	>	}
2985	>
2986	>	root = (p.red) ? r : balanceDeletion(r, replacement);
2987	>
2988	>	if (p == replacement) {  // detach pointers
2989	>	TreeNode<K,V> pp;
2990	>	if ((pp = p.parent) != null) {
2991	>	if (p == pp.left)
2992	>	pp.left = null;
2993	>	else if (p == pp.right)
2994	>	pp.right = null;
2995	>	p.parent = null;
2996	>	}
2997	>	}
2998	>	} finally {
2999	>	unlockRoot();
3000	>	}
3001	>	assert checkInvariants(root);
3002	>	return false;
3003	>	}
3004	>
3005	>	/* ------------------------------------------------------------ */
3006	>	// Red-black tree methods, all adapted from CLR
3007	>
3008	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3009	>	TreeNode<K,V> p) {
3010	>	TreeNode<K,V> r, pp, rl;
3011	>	if (p != null && (r = p.right) != null) {
3012	>	if ((rl = p.right = r.left) != null)
3013	>	rl.parent = p;
3014	>	if ((pp = r.parent = p.parent) == null)
3015	>	(root = r).red = false;
3016	>	else if (pp.left == p)
3017	>	pp.left = r;
3018	>	else
3019	>	pp.right = r;
3020	>	r.left = p;
3021	>	p.parent = r;
3022	>	}
3023	>	return root;
3024	>	}
3025	>
3026	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3027	>	TreeNode<K,V> p) {
3028	>	TreeNode<K,V> l, pp, lr;
3029	>	if (p != null && (l = p.left) != null) {
3030	>	if ((lr = p.left = l.right) != null)
3031	>	lr.parent = p;
3032	>	if ((pp = l.parent = p.parent) == null)
3033	>	(root = l).red = false;
3034	>	else if (pp.right == p)
3035	>	pp.right = l;
3036	>	else
3037	>	pp.left = l;
3038	>	l.right = p;
3039	>	p.parent = l;
3040	>	}
3041	>	return root;
3042	>	}
3043	>
3044	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3045	>	TreeNode<K,V> x) {
3046	>	x.red = true;
3047	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3048	>	if ((xp = x.parent) == null) {
3049	>	x.red = false;
3050	>	return x;
3051	>	}
3052	>	else if (!xp.red || (xpp = xp.parent) == null)
3053	>	return root;
3054	>	if (xp == (xppl = xpp.left)) {
3055	>	if ((xppr = xpp.right) != null && xppr.red) {
3056	>	xppr.red = false;
3057	>	xp.red = false;
3058	>	xpp.red = true;
3059	>	x = xpp;
3060	>	}
3061	>	else {
3062	>	if (x == xp.right) {
3063	>	root = rotateLeft(root, x = xp);
3064	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3065	>	}
3066	>	if (xp != null) {
3067	>	xp.red = false;
3068	>	if (xpp != null) {
3069	>	xpp.red = true;
3070	>	root = rotateRight(root, xpp);
3071	>	}
3072	>	}
3073	>	}
3074	>	}
3075	>	else {
3076	>	if (xppl != null && xppl.red) {
3077	>	xppl.red = false;
3078	>	xp.red = false;
3079	>	xpp.red = true;
3080	>	x = xpp;
3081	>	}
3082	>	else {
3083	>	if (x == xp.left) {
3084	>	root = rotateRight(root, x = xp);
3085	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3086	>	}
3087	>	if (xp != null) {
3088	>	xp.red = false;
3089	>	if (xpp != null) {
3090	>	xpp.red = true;
3091	>	root = rotateLeft(root, xpp);
3092	>	}
3093	>	}
3094	>	}
3095	>	}
3096	>	}
3097	>	}
3098	>
3099	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3100	>	TreeNode<K,V> x) {
3101	>	for (TreeNode<K,V> xp, xpl, xpr;;)  {
3102	>	if (x == null || x == root)
3103	>	return root;
3104	>	else if ((xp = x.parent) == null) {
3105	>	x.red = false;
3106	>	return x;
3107	>	}
3108	>	else if (x.red) {
3109	>	x.red = false;
3110	>	return root;
3111	>	}
3112	>	else if ((xpl = xp.left) == x) {
3113	>	if ((xpr = xp.right) != null && xpr.red) {
3114	>	xpr.red = false;
3115	>	xp.red = true;
3116	>	root = rotateLeft(root, xp);
3117	>	xpr = (xp = x.parent) == null ? null : xp.right;
3118	>	}
3119	>	if (xpr == null)
3120	>	x = xp;
3121	>	else {
3122	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3123	>	if ((sr == null || !sr.red) &&
3124	>	(sl == null || !sl.red)) {
3125	>	xpr.red = true;
3126	>	x = xp;
3127	>	}
3128	>	else {
3129	>	if (sr == null || !sr.red) {
3130	>	if (sl != null)
3131	>	sl.red = false;
3132	>	xpr.red = true;
3133	>	root = rotateRight(root, xpr);
3134	>	xpr = (xp = x.parent) == null ?
3135	>	null : xp.right;
3136	>	}
3137	>	if (xpr != null) {
3138	>	xpr.red = (xp == null) ? false : xp.red;
3139	>	if ((sr = xpr.right) != null)
3140	>	sr.red = false;
3141	>	}
3142	>	if (xp != null) {
3143	>	xp.red = false;
3144	>	root = rotateLeft(root, xp);
3145	>	}
3146	>	x = root;
3147	>	}
3148	>	}
3149	>	}
3150	>	else { // symmetric
3151	>	if (xpl != null && xpl.red) {
3152	>	xpl.red = false;
3153	>	xp.red = true;
3154	>	root = rotateRight(root, xp);
3155	>	xpl = (xp = x.parent) == null ? null : xp.left;
3156	>	}
3157	>	if (xpl == null)
3158	>	x = xp;
3159	>	else {
3160	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3161	>	if ((sl == null || !sl.red) &&
3162	>	(sr == null || !sr.red)) {
3163	>	xpl.red = true;
3164	>	x = xp;
3165	>	}
3166	>	else {
3167	>	if (sl == null || !sl.red) {
3168	>	if (sr != null)
3169	>	sr.red = false;
3170	>	xpl.red = true;
3171	>	root = rotateLeft(root, xpl);
3172	>	xpl = (xp = x.parent) == null ?
3173	>	null : xp.left;
3174	>	}
3175	>	if (xpl != null) {
3176	>	xpl.red = (xp == null) ? false : xp.red;
3177	>	if ((sl = xpl.left) != null)
3178	>	sl.red = false;
3179	>	}
3180	>	if (xp != null) {
3181	>	xp.red = false;
3182	>	root = rotateRight(root, xp);
3183	>	}
3184	>	x = root;
3185	>	}
3186	>	}
3187	>	}
3188	>	}
3189	>	}
3190	>
3191	>	/**
3192	>	* Recursive invariant check
3193	>	*/
3194	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3195	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3196	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3197	>	if (tb != null && tb.next != t)
3198	>	return false;
3199	>	if (tn != null && tn.prev != t)
3200	>	return false;
3201	>	if (tp != null && t != tp.left && t != tp.right)
3202	>	return false;
3203	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3204	>	return false;
3205	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3206	>	return false;
3207	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3208	>	return false;
3209	>	if (tl != null && !checkInvariants(tl))
3210	>	return false;
3211	>	if (tr != null && !checkInvariants(tr))
3212	>	return false;
3213	>	return true;
3214	>	}
3215	>
3216	>	private static final sun.misc.Unsafe U;
3217	>	private static final long LOCKSTATE;
3218	>	static {
3219	>	try {
3220	>	U = sun.misc.Unsafe.getUnsafe();
3221	>	Class<?> k = TreeBin.class;
3222	>	LOCKSTATE = U.objectFieldOffset
3223	>	(k.getDeclaredField("lockState"));
3224	>	} catch (Exception e) {
3225	>	throw new Error(e);
3226	>	}
3227	>	}
3228	>	}
3229	>
3230	>	/* ----------------Table Traversal -------------- */
3231	>
3232	>	/**
3233	>	* Records the table, its length, and current traversal index for a
3234	>	* traverser that must process a region of a forwarded table before
3235	>	* proceeding with current table.
3236	>	*/
3237	>	static final class TableStack<K,V> {
3238	>	int length;
3239	>	int index;
3240	>	Node<K,V>[] tab;
3241	>	TableStack<K,V> next;
3242	>	}
3243	>
3244	>	/**
3245	>	* Encapsulates traversal for methods such as containsValue; also
3246	>	* serves as a base class for other iterators and spliterators.
3247	>	*
3248	>	* Method advance visits once each still-valid node that was
3249	>	* reachable upon iterator construction. It might miss some that
3250	>	* were added to a bin after the bin was visited, which is OK wrt
3251	>	* consistency guarantees. Maintaining this property in the face
3252	>	* of possible ongoing resizes requires a fair amount of
3253	>	* bookkeeping state that is difficult to optimize away amidst
3254	>	* volatile accesses.  Even so, traversal maintains reasonable
3255	>	* throughput.
3256	>	*
3257	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3258	>	* However, if the table has been resized, then all future steps
3259	>	* must traverse both the bin at the current index as well as at
3260	>	* (index + baseSize); and so on for further resizings. To
3261	>	* paranoically cope with potential sharing by users of iterators
3262	>	* across threads, iteration terminates if a bounds checks fails
3263	>	* for a table read.
3264	>	*/
3265	>	static class Traverser<K,V> {
3266	>	Node<K,V>[] tab;        // current table; updated if resized
3267	>	Node<K,V> next;         // the next entry to use
3268	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3269	>	int index;              // index of bin to use next
3270	>	int baseIndex;          // current index of initial table
3271	>	int baseLimit;          // index bound for initial table
3272	>	final int baseSize;     // initial table size
3273	>
3274	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3275	>	this.tab = tab;
3276	>	this.baseSize = size;
3277	>	this.baseIndex = this.index = index;
3278	>	this.baseLimit = limit;
3279	>	this.next = null;
3280	>	}
3281	>
3282	>	/**
3283	>	* Advances if possible, returning next valid node, or null if none.
3284	>	*/
3285	>	final Node<K,V> advance() {
3286	>	Node<K,V> e;
3287	>	if ((e = next) != null)
3288	>	e = e.next;
3289	>	for (;;) {
3290	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3291	>	if (e != null)
3292	>	return next = e;
3293	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3294	>	(n = t.length) <= (i = index) || i < 0)
3295	>	return next = null;
3296	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3297	>	if (e instanceof ForwardingNode) {
3298	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3299	>	e = null;
3300	>	pushState(t, i, n);
3301	>	continue;
3302	>	}
3303	>	else if (e instanceof TreeBin)
3304	>	e = ((TreeBin<K,V>)e).first;
3305	>	else
3306	>	e = null;
3307	>	}
3308	>	if (stack != null)
3309	>	recoverState(n);
3310	>	else if ((index = i + baseSize) >= n)
3311	>	index = ++baseIndex; // visit upper slots if present
3312	>	}
3313	>	}
3314	>
3315	>	/**
3316	>	* Saves traversal state upon encountering a forwarding node.
3317	>	*/
3318	>	private void pushState(Node<K,V>[] t, int i, int n) {
3319	>	TableStack<K,V> s = spare;  // reuse if possible
3320	>	if (s != null)
3321	>	spare = s.next;
3322	>	else
3323	>	s = new TableStack<K,V>();
3324	>	s.tab = t;
3325	>	s.length = n;
3326	>	s.index = i;
3327	>	s.next = stack;
3328	>	stack = s;
3329	>	}
3330	>
3331	>	/**
3332	>	* Possibly pops traversal state.
3333	>	*
3334	>	* @param n length of current table
3335	>	*/
3336	>	private void recoverState(int n) {
3337	>	TableStack<K,V> s; int len;
3338	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3339	>	n = len;
3340	>	index = s.index;
3341	>	tab = s.tab;
3342	>	s.tab = null;
3343	>	TableStack<K,V> next = s.next;
3344	>	s.next = spare; // save for reuse
3345	>	stack = next;
3346	>	spare = s;
3347	>	}
3348	>	if (s == null && (index += baseSize) >= n)
3349	>	index = ++baseIndex;
3350	>	}
3351	>	}
3352	>
3353	>	/**
3354	>	* Base of key, value, and entry Iterators. Adds fields to
3355	>	* Traverser to support iterator.remove.
3356	>	*/
3357	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3358	>	final ConcurrentHashMap<K,V> map;
3359	>	Node<K,V> lastReturned;
3360	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3361	>	ConcurrentHashMap<K,V> map) {
3362	>	super(tab, size, index, limit);
3363	>	this.map = map;
3364		advance();
1098	–	return lastReturned;
3365		}
3366
3367	<	public void remove() {
3368	<	if (lastReturned == null)
3367	>	public final boolean hasNext() { return next != null; }
3368	>	public final boolean hasMoreElements() { return next != null; }
3369	>
3370	>	public final void remove() {
3371	>	Node<K,V> p;
3372	>	if ((p = lastReturned) == null)
3373		throw new IllegalStateException();
1104	–	ConcurrentHashMap.this.remove(lastReturned.key);
3374		lastReturned = null;
3375	+	map.replaceNode(p.key, null, null);
3376		}
3377		}
3378
3379	<	final class KeyIterator
3380	<	extends HashIterator
3381	<	implements Iterator<K>, Enumeration<K>
3382	<	{
3383	<	public K next()        { return super.nextEntry().key; }
3384	<	public K nextElement() { return super.nextEntry().key; }
3379	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3380	>	implements Iterator<K>, Enumeration<K> {
3381	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3382	>	ConcurrentHashMap<K,V> map) {
3383	>	super(tab, index, size, limit, map);
3384	>	}
3385	>
3386	>	public final K next() {
3387	>	Node<K,V> p;
3388	>	if ((p = next) == null)
3389	>	throw new NoSuchElementException();
3390	>	K k = p.key;
3391	>	lastReturned = p;
3392	>	advance();
3393	>	return k;
3394	>	}
3395	>
3396	>	public final K nextElement() { return next(); }
3397		}
3398
3399	<	final class ValueIterator
3400	<	extends HashIterator
3401	<	implements Iterator<V>, Enumeration<V>
3402	<	{
3403	<	public V next()        { return super.nextEntry().value; }
3404	<	public V nextElement() { return super.nextEntry().value; }
3399	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3400	>	implements Iterator<V>, Enumeration<V> {
3401	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3402	>	ConcurrentHashMap<K,V> map) {
3403	>	super(tab, index, size, limit, map);
3404	>	}
3405	>
3406	>	public final V next() {
3407	>	Node<K,V> p;
3408	>	if ((p = next) == null)
3409	>	throw new NoSuchElementException();
3410	>	V v = p.val;
3411	>	lastReturned = p;
3412	>	advance();
3413	>	return v;
3414	>	}
3415	>
3416	>	public final V nextElement() { return next(); }
3417	>	}
3418	>
3419	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3420	>	implements Iterator<Map.Entry<K,V>> {
3421	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3422	>	ConcurrentHashMap<K,V> map) {
3423	>	super(tab, index, size, limit, map);
3424	>	}
3425	>
3426	>	public final Map.Entry<K,V> next() {
3427	>	Node<K,V> p;
3428	>	if ((p = next) == null)
3429	>	throw new NoSuchElementException();
3430	>	K k = p.key;
3431	>	V v = p.val;
3432	>	lastReturned = p;
3433	>	advance();
3434	>	return new MapEntry<K,V>(k, v, map);
3435	>	}
3436		}
3437
3438		/**
3439	<	* Custom Entry class used by EntryIterator.next(), that relays
1127	<	* setValue changes to the underlying map.
3439	>	* Exported Entry for EntryIterator
3440		*/
3441	<	final class WriteThroughEntry
3442	<	extends AbstractMap.SimpleEntry<K,V>
3443	<	{
3444	<	WriteThroughEntry(K k, V v) {
3445	<	super(k,v);
3441	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3442	>	final K key; // non-null
3443	>	V val;       // non-null
3444	>	final ConcurrentHashMap<K,V> map;
3445	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3446	>	this.key = key;
3447	>	this.val = val;
3448	>	this.map = map;
3449	>	}
3450	>	public K getKey()        { return key; }
3451	>	public V getValue()      { return val; }
3452	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3453	>	public String toString() { return key + "=" + val; }
3454	>
3455	>	public boolean equals(Object o) {
3456	>	Object k, v; Map.Entry<?,?> e;
3457	>	return ((o instanceof Map.Entry) &&
3458	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3459	>	(v = e.getValue()) != null &&
3460	>	(k == key || k.equals(key)) &&
3461	>	(v == val || v.equals(val)));
3462		}
3463
3464		/**
3465	<	* Set our entry's value and write through to the map. The
3466	<	* value to return is somewhat arbitrary here. Since a
3467	<	* WriteThroughEntry does not necessarily track asynchronous
3468	<	* changes, the most recent "previous" value could be
3469	<	* different from what we return (or could even have been
3470	<	* removed in which case the put will re-establish). We do not
1143	<	* and cannot guarantee more.
3465	>	* Sets our entry's value and writes through to the map. The
3466	>	* value to return is somewhat arbitrary here. Since we do not
3467	>	* necessarily track asynchronous changes, the most recent
3468	>	* "previous" value could be different from what we return (or
3469	>	* could even have been removed, in which case the put will
3470	>	* re-establish). We do not and cannot guarantee more.
3471		*/
3472	<	public V setValue(V value) {
3472	>	public V setValue(V value) {
3473		if (value == null) throw new NullPointerException();
3474	<	V v = super.setValue(value);
3475	<	ConcurrentHashMap.this.put(getKey(), value);
3474	>	V v = val;
3475	>	val = value;
3476	>	map.put(key, value);
3477		return v;
3478		}
3479		}
3480
3481	<	final class EntryIterator
3482	<	extends HashIterator
3483	<	implements Iterator<Entry<K,V>>
3484	<	{
3485	<	public Map.Entry<K,V> next() {
3486	<	HashEntry<K,V> e = super.nextEntry();
3487	<	return new WriteThroughEntry(e.key, e.value);
3481	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3482	>	implements Spliterator<K> {
3483	>	long est;               // size estimate
3484	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3485	>	long est) {
3486	>	super(tab, size, index, limit);
3487	>	this.est = est;
3488	>	}
3489	>
3490	>	public Spliterator<K> trySplit() {
3491	>	int i, f, h;
3492	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3493	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3494	>	f, est >>>= 1);
3495	>	}
3496	>
3497	>	public void forEachRemaining(Consumer<? super K> action) {
3498	>	if (action == null) throw new NullPointerException();
3499	>	for (Node<K,V> p; (p = advance()) != null;)
3500	>	action.accept(p.key);
3501	>	}
3502	>
3503	>	public boolean tryAdvance(Consumer<? super K> action) {
3504	>	if (action == null) throw new NullPointerException();
3505	>	Node<K,V> p;
3506	>	if ((p = advance()) == null)
3507	>	return false;
3508	>	action.accept(p.key);
3509	>	return true;
3510	>	}
3511	>
3512	>	public long estimateSize() { return est; }
3513	>
3514	>	public int characteristics() {
3515	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3516	>	Spliterator.NONNULL;
3517		}
3518		}
3519
3520	<	final class KeySet extends AbstractSet<K> {
3521	<	public Iterator<K> iterator() {
3522	<	return new KeyIterator();
3520	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3521	>	implements Spliterator<V> {
3522	>	long est;               // size estimate
3523	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3524	>	long est) {
3525	>	super(tab, size, index, limit);
3526	>	this.est = est;
3527	>	}
3528	>
3529	>	public Spliterator<V> trySplit() {
3530	>	int i, f, h;
3531	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3532	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3533	>	f, est >>>= 1);
3534	>	}
3535	>
3536	>	public void forEachRemaining(Consumer<? super V> action) {
3537	>	if (action == null) throw new NullPointerException();
3538	>	for (Node<K,V> p; (p = advance()) != null;)
3539	>	action.accept(p.val);
3540	>	}
3541	>
3542	>	public boolean tryAdvance(Consumer<? super V> action) {
3543	>	if (action == null) throw new NullPointerException();
3544	>	Node<K,V> p;
3545	>	if ((p = advance()) == null)
3546	>	return false;
3547	>	action.accept(p.val);
3548	>	return true;
3549		}
3550	<	public int size() {
3551	<	return ConcurrentHashMap.this.size();
3550	>
3551	>	public long estimateSize() { return est; }
3552	>
3553	>	public int characteristics() {
3554	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3555		}
3556	<	public boolean contains(Object o) {
3557	<	return ConcurrentHashMap.this.containsKey(o);
3556	>	}
3557	>
3558	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3559	>	implements Spliterator<Map.Entry<K,V>> {
3560	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3561	>	long est;               // size estimate
3562	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3563	>	long est, ConcurrentHashMap<K,V> map) {
3564	>	super(tab, size, index, limit);
3565	>	this.map = map;
3566	>	this.est = est;
3567	>	}
3568	>
3569	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3570	>	int i, f, h;
3571	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3572	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3573	>	f, est >>>= 1, map);
3574	>	}
3575	>
3576	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3577	>	if (action == null) throw new NullPointerException();
3578	>	for (Node<K,V> p; (p = advance()) != null; )
3579	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3580	>	}
3581	>
3582	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3583	>	if (action == null) throw new NullPointerException();
3584	>	Node<K,V> p;
3585	>	if ((p = advance()) == null)
3586	>	return false;
3587	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3588	>	return true;
3589		}
3590	<	public boolean remove(Object o) {
3591	<	return ConcurrentHashMap.this.remove(o) != null;
3590	>
3591	>	public long estimateSize() { return est; }
3592	>
3593	>	public int characteristics() {
3594	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3595	>	Spliterator.NONNULL;
3596	>	}
3597	>	}
3598	>
3599	>	// Parallel bulk operations
3600	>
3601	>	/**
3602	>	* Computes initial batch value for bulk tasks. The returned value
3603	>	* is approximately exp2 of the number of times (minus one) to
3604	>	* split task by two before executing leaf action. This value is
3605	>	* faster to compute and more convenient to use as a guide to
3606	>	* splitting than is the depth, since it is used while dividing by
3607	>	* two anyway.
3608	>	*/
3609	>	final int batchFor(long b) {
3610	>	long n;
3611	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3612	>	return 0;
3613	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3614	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3615	>	}
3616	>
3617	>	/**
3618	>	* Performs the given action for each (key, value).
3619	>	*
3620	>	* @param parallelismThreshold the (estimated) number of elements
3621	>	* needed for this operation to be executed in parallel
3622	>	* @param action the action
3623	>	* @since 1.8
3624	>	*/
3625	>	public void forEach(long parallelismThreshold,
3626	>	BiConsumer<? super K,? super V> action) {
3627	>	if (action == null) throw new NullPointerException();
3628	>	new ForEachMappingTask<K,V>
3629	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3630	>	action).invoke();
3631	>	}
3632	>
3633	>	/**
3634	>	* Performs the given action for each non-null transformation
3635	>	* of each (key, value).
3636	>	*
3637	>	* @param parallelismThreshold the (estimated) number of elements
3638	>	* needed for this operation to be executed in parallel
3639	>	* @param transformer a function returning the transformation
3640	>	* for an element, or null if there is no transformation (in
3641	>	* which case the action is not applied)
3642	>	* @param action the action
3643	>	* @param <U> the return type of the transformer
3644	>	* @since 1.8
3645	>	*/
3646	>	public <U> void forEach(long parallelismThreshold,
3647	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3648	>	Consumer<? super U> action) {
3649	>	if (transformer == null || action == null)
3650	>	throw new NullPointerException();
3651	>	new ForEachTransformedMappingTask<K,V,U>
3652	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3653	>	transformer, action).invoke();
3654	>	}
3655	>
3656	>	/**
3657	>	* Returns a non-null result from applying the given search
3658	>	* function on each (key, value), or null if none.  Upon
3659	>	* success, further element processing is suppressed and the
3660	>	* results of any other parallel invocations of the search
3661	>	* function are ignored.
3662	>	*
3663	>	* @param parallelismThreshold the (estimated) number of elements
3664	>	* needed for this operation to be executed in parallel
3665	>	* @param searchFunction a function returning a non-null
3666	>	* result on success, else null
3667	>	* @param <U> the return type of the search function
3668	>	* @return a non-null result from applying the given search
3669	>	* function on each (key, value), or null if none
3670	>	* @since 1.8
3671	>	*/
3672	>	public <U> U search(long parallelismThreshold,
3673	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3674	>	if (searchFunction == null) throw new NullPointerException();
3675	>	return new SearchMappingsTask<K,V,U>
3676	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3677	>	searchFunction, new AtomicReference<U>()).invoke();
3678	>	}
3679	>
3680	>	/**
3681	>	* Returns the result of accumulating the given transformation
3682	>	* of all (key, value) pairs using the given reducer to
3683	>	* combine values, or null if none.
3684	>	*
3685	>	* @param parallelismThreshold the (estimated) number of elements
3686	>	* needed for this operation to be executed in parallel
3687	>	* @param transformer a function returning the transformation
3688	>	* for an element, or null if there is no transformation (in
3689	>	* which case it is not combined)
3690	>	* @param reducer a commutative associative combining function
3691	>	* @param <U> the return type of the transformer
3692	>	* @return the result of accumulating the given transformation
3693	>	* of all (key, value) pairs
3694	>	* @since 1.8
3695	>	*/
3696	>	public <U> U reduce(long parallelismThreshold,
3697	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3698	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3699	>	if (transformer == null || reducer == null)
3700	>	throw new NullPointerException();
3701	>	return new MapReduceMappingsTask<K,V,U>
3702	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3703	>	null, transformer, reducer).invoke();
3704	>	}
3705	>
3706	>	/**
3707	>	* Returns the result of accumulating the given transformation
3708	>	* of all (key, value) pairs using the given reducer to
3709	>	* combine values, and the given basis as an identity value.
3710	>	*
3711	>	* @param parallelismThreshold the (estimated) number of elements
3712	>	* needed for this operation to be executed in parallel
3713	>	* @param transformer a function returning the transformation
3714	>	* for an element
3715	>	* @param basis the identity (initial default value) for the reduction
3716	>	* @param reducer a commutative associative combining function
3717	>	* @return the result of accumulating the given transformation
3718	>	* of all (key, value) pairs
3719	>	* @since 1.8
3720	>	*/
3721	>	public double reduceToDouble(long parallelismThreshold,
3722	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3723	>	double basis,
3724	>	DoubleBinaryOperator reducer) {
3725	>	if (transformer == null || reducer == null)
3726	>	throw new NullPointerException();
3727	>	return new MapReduceMappingsToDoubleTask<K,V>
3728	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3729	>	null, transformer, basis, reducer).invoke();
3730	>	}
3731	>
3732	>	/**
3733	>	* Returns the result of accumulating the given transformation
3734	>	* of all (key, value) pairs using the given reducer to
3735	>	* combine values, and the given basis as an identity value.
3736	>	*
3737	>	* @param parallelismThreshold the (estimated) number of elements
3738	>	* needed for this operation to be executed in parallel
3739	>	* @param transformer a function returning the transformation
3740	>	* for an element
3741	>	* @param basis the identity (initial default value) for the reduction
3742	>	* @param reducer a commutative associative combining function
3743	>	* @return the result of accumulating the given transformation
3744	>	* of all (key, value) pairs
3745	>	* @since 1.8
3746	>	*/
3747	>	public long reduceToLong(long parallelismThreshold,
3748	>	ToLongBiFunction<? super K, ? super V> transformer,
3749	>	long basis,
3750	>	LongBinaryOperator reducer) {
3751	>	if (transformer == null || reducer == null)
3752	>	throw new NullPointerException();
3753	>	return new MapReduceMappingsToLongTask<K,V>
3754	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3755	>	null, transformer, basis, reducer).invoke();
3756	>	}
3757	>
3758	>	/**
3759	>	* Returns the result of accumulating the given transformation
3760	>	* of all (key, value) pairs using the given reducer to
3761	>	* combine values, and the given basis as an identity value.
3762	>	*
3763	>	* @param parallelismThreshold the (estimated) number of elements
3764	>	* needed for this operation to be executed in parallel
3765	>	* @param transformer a function returning the transformation
3766	>	* for an element
3767	>	* @param basis the identity (initial default value) for the reduction
3768	>	* @param reducer a commutative associative combining function
3769	>	* @return the result of accumulating the given transformation
3770	>	* of all (key, value) pairs
3771	>	* @since 1.8
3772	>	*/
3773	>	public int reduceToInt(long parallelismThreshold,
3774	>	ToIntBiFunction<? super K, ? super V> transformer,
3775	>	int basis,
3776	>	IntBinaryOperator reducer) {
3777	>	if (transformer == null || reducer == null)
3778	>	throw new NullPointerException();
3779	>	return new MapReduceMappingsToIntTask<K,V>
3780	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3781	>	null, transformer, basis, reducer).invoke();
3782	>	}
3783	>
3784	>	/**
3785	>	* Performs the given action for each key.
3786	>	*
3787	>	* @param parallelismThreshold the (estimated) number of elements
3788	>	* needed for this operation to be executed in parallel
3789	>	* @param action the action
3790	>	* @since 1.8
3791	>	*/
3792	>	public void forEachKey(long parallelismThreshold,
3793	>	Consumer<? super K> action) {
3794	>	if (action == null) throw new NullPointerException();
3795	>	new ForEachKeyTask<K,V>
3796	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3797	>	action).invoke();
3798	>	}
3799	>
3800	>	/**
3801	>	* Performs the given action for each non-null transformation
3802	>	* of each key.
3803	>	*
3804	>	* @param parallelismThreshold the (estimated) number of elements
3805	>	* needed for this operation to be executed in parallel
3806	>	* @param transformer a function returning the transformation
3807	>	* for an element, or null if there is no transformation (in
3808	>	* which case the action is not applied)
3809	>	* @param action the action
3810	>	* @param <U> the return type of the transformer
3811	>	* @since 1.8
3812	>	*/
3813	>	public <U> void forEachKey(long parallelismThreshold,
3814	>	Function<? super K, ? extends U> transformer,
3815	>	Consumer<? super U> action) {
3816	>	if (transformer == null || action == null)
3817	>	throw new NullPointerException();
3818	>	new ForEachTransformedKeyTask<K,V,U>
3819	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3820	>	transformer, action).invoke();
3821	>	}
3822	>
3823	>	/**
3824	>	* Returns a non-null result from applying the given search
3825	>	* function on each key, or null if none. Upon success,
3826	>	* further element processing is suppressed and the results of
3827	>	* any other parallel invocations of the search function are
3828	>	* ignored.
3829	>	*
3830	>	* @param parallelismThreshold the (estimated) number of elements
3831	>	* needed for this operation to be executed in parallel
3832	>	* @param searchFunction a function returning a non-null
3833	>	* result on success, else null
3834	>	* @param <U> the return type of the search function
3835	>	* @return a non-null result from applying the given search
3836	>	* function on each key, or null if none
3837	>	* @since 1.8
3838	>	*/
3839	>	public <U> U searchKeys(long parallelismThreshold,
3840	>	Function<? super K, ? extends U> searchFunction) {
3841	>	if (searchFunction == null) throw new NullPointerException();
3842	>	return new SearchKeysTask<K,V,U>
3843	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3844	>	searchFunction, new AtomicReference<U>()).invoke();
3845	>	}
3846	>
3847	>	/**
3848	>	* Returns the result of accumulating all keys using the given
3849	>	* reducer to combine values, or null if none.
3850	>	*
3851	>	* @param parallelismThreshold the (estimated) number of elements
3852	>	* needed for this operation to be executed in parallel
3853	>	* @param reducer a commutative associative combining function
3854	>	* @return the result of accumulating all keys using the given
3855	>	* reducer to combine values, or null if none
3856	>	* @since 1.8
3857	>	*/
3858	>	public K reduceKeys(long parallelismThreshold,
3859	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3860	>	if (reducer == null) throw new NullPointerException();
3861	>	return new ReduceKeysTask<K,V>
3862	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3863	>	null, reducer).invoke();
3864	>	}
3865	>
3866	>	/**
3867	>	* Returns the result of accumulating the given transformation
3868	>	* of all keys using the given reducer to combine values, or
3869	>	* null if none.
3870	>	*
3871	>	* @param parallelismThreshold the (estimated) number of elements
3872	>	* needed for this operation to be executed in parallel
3873	>	* @param transformer a function returning the transformation
3874	>	* for an element, or null if there is no transformation (in
3875	>	* which case it is not combined)
3876	>	* @param reducer a commutative associative combining function
3877	>	* @param <U> the return type of the transformer
3878	>	* @return the result of accumulating the given transformation
3879	>	* of all keys
3880	>	* @since 1.8
3881	>	*/
3882	>	public <U> U reduceKeys(long parallelismThreshold,
3883	>	Function<? super K, ? extends U> transformer,
3884	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3885	>	if (transformer == null || reducer == null)
3886	>	throw new NullPointerException();
3887	>	return new MapReduceKeysTask<K,V,U>
3888	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3889	>	null, transformer, reducer).invoke();
3890	>	}
3891	>
3892	>	/**
3893	>	* Returns the result of accumulating the given transformation
3894	>	* of all keys using the given reducer to combine values, and
3895	>	* the given basis as an identity value.
3896	>	*
3897	>	* @param parallelismThreshold the (estimated) number of elements
3898	>	* needed for this operation to be executed in parallel
3899	>	* @param transformer a function returning the transformation
3900	>	* for an element
3901	>	* @param basis the identity (initial default value) for the reduction
3902	>	* @param reducer a commutative associative combining function
3903	>	* @return the result of accumulating the given transformation
3904	>	* of all keys
3905	>	* @since 1.8
3906	>	*/
3907	>	public double reduceKeysToDouble(long parallelismThreshold,
3908	>	ToDoubleFunction<? super K> transformer,
3909	>	double basis,
3910	>	DoubleBinaryOperator reducer) {
3911	>	if (transformer == null || reducer == null)
3912	>	throw new NullPointerException();
3913	>	return new MapReduceKeysToDoubleTask<K,V>
3914	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3915	>	null, transformer, basis, reducer).invoke();
3916	>	}
3917	>
3918	>	/**
3919	>	* Returns the result of accumulating the given transformation
3920	>	* of all keys using the given reducer to combine values, and
3921	>	* the given basis as an identity value.
3922	>	*
3923	>	* @param parallelismThreshold the (estimated) number of elements
3924	>	* needed for this operation to be executed in parallel
3925	>	* @param transformer a function returning the transformation
3926	>	* for an element
3927	>	* @param basis the identity (initial default value) for the reduction
3928	>	* @param reducer a commutative associative combining function
3929	>	* @return the result of accumulating the given transformation
3930	>	* of all keys
3931	>	* @since 1.8
3932	>	*/
3933	>	public long reduceKeysToLong(long parallelismThreshold,
3934	>	ToLongFunction<? super K> transformer,
3935	>	long basis,
3936	>	LongBinaryOperator reducer) {
3937	>	if (transformer == null || reducer == null)
3938	>	throw new NullPointerException();
3939	>	return new MapReduceKeysToLongTask<K,V>
3940	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3941	>	null, transformer, basis, reducer).invoke();
3942	>	}
3943	>
3944	>	/**
3945	>	* Returns the result of accumulating the given transformation
3946	>	* of all keys using the given reducer to combine values, and
3947	>	* the given basis as an identity value.
3948	>	*
3949	>	* @param parallelismThreshold the (estimated) number of elements
3950	>	* needed for this operation to be executed in parallel
3951	>	* @param transformer a function returning the transformation
3952	>	* for an element
3953	>	* @param basis the identity (initial default value) for the reduction
3954	>	* @param reducer a commutative associative combining function
3955	>	* @return the result of accumulating the given transformation
3956	>	* of all keys
3957	>	* @since 1.8
3958	>	*/
3959	>	public int reduceKeysToInt(long parallelismThreshold,
3960	>	ToIntFunction<? super K> transformer,
3961	>	int basis,
3962	>	IntBinaryOperator reducer) {
3963	>	if (transformer == null || reducer == null)
3964	>	throw new NullPointerException();
3965	>	return new MapReduceKeysToIntTask<K,V>
3966	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3967	>	null, transformer, basis, reducer).invoke();
3968	>	}
3969	>
3970	>	/**
3971	>	* Performs the given action for each value.
3972	>	*
3973	>	* @param parallelismThreshold the (estimated) number of elements
3974	>	* needed for this operation to be executed in parallel
3975	>	* @param action the action
3976	>	* @since 1.8
3977	>	*/
3978	>	public void forEachValue(long parallelismThreshold,
3979	>	Consumer<? super V> action) {
3980	>	if (action == null)
3981	>	throw new NullPointerException();
3982	>	new ForEachValueTask<K,V>
3983	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3984	>	action).invoke();
3985	>	}
3986	>
3987	>	/**
3988	>	* Performs the given action for each non-null transformation
3989	>	* of each value.
3990	>	*
3991	>	* @param parallelismThreshold the (estimated) number of elements
3992	>	* needed for this operation to be executed in parallel
3993	>	* @param transformer a function returning the transformation
3994	>	* for an element, or null if there is no transformation (in
3995	>	* which case the action is not applied)
3996	>	* @param action the action
3997	>	* @param <U> the return type of the transformer
3998	>	* @since 1.8
3999	>	*/
4000	>	public <U> void forEachValue(long parallelismThreshold,
4001	>	Function<? super V, ? extends U> transformer,
4002	>	Consumer<? super U> action) {
4003	>	if (transformer == null || action == null)
4004	>	throw new NullPointerException();
4005	>	new ForEachTransformedValueTask<K,V,U>
4006	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4007	>	transformer, action).invoke();
4008	>	}
4009	>
4010	>	/**
4011	>	* Returns a non-null result from applying the given search
4012	>	* function on each value, or null if none.  Upon success,
4013	>	* further element processing is suppressed and the results of
4014	>	* any other parallel invocations of the search function are
4015	>	* ignored.
4016	>	*
4017	>	* @param parallelismThreshold the (estimated) number of elements
4018	>	* needed for this operation to be executed in parallel
4019	>	* @param searchFunction a function returning a non-null
4020	>	* result on success, else null
4021	>	* @param <U> the return type of the search function
4022	>	* @return a non-null result from applying the given search
4023	>	* function on each value, or null if none
4024	>	* @since 1.8
4025	>	*/
4026	>	public <U> U searchValues(long parallelismThreshold,
4027	>	Function<? super V, ? extends U> searchFunction) {
4028	>	if (searchFunction == null) throw new NullPointerException();
4029	>	return new SearchValuesTask<K,V,U>
4030	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4031	>	searchFunction, new AtomicReference<U>()).invoke();
4032	>	}
4033	>
4034	>	/**
4035	>	* Returns the result of accumulating all values using the
4036	>	* given reducer to combine values, or null if none.
4037	>	*
4038	>	* @param parallelismThreshold the (estimated) number of elements
4039	>	* needed for this operation to be executed in parallel
4040	>	* @param reducer a commutative associative combining function
4041	>	* @return the result of accumulating all values
4042	>	* @since 1.8
4043	>	*/
4044	>	public V reduceValues(long parallelismThreshold,
4045	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4046	>	if (reducer == null) throw new NullPointerException();
4047	>	return new ReduceValuesTask<K,V>
4048	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4049	>	null, reducer).invoke();
4050	>	}
4051	>
4052	>	/**
4053	>	* Returns the result of accumulating the given transformation
4054	>	* of all values using the given reducer to combine values, or
4055	>	* null if none.
4056	>	*
4057	>	* @param parallelismThreshold the (estimated) number of elements
4058	>	* needed for this operation to be executed in parallel
4059	>	* @param transformer a function returning the transformation
4060	>	* for an element, or null if there is no transformation (in
4061	>	* which case it is not combined)
4062	>	* @param reducer a commutative associative combining function
4063	>	* @param <U> the return type of the transformer
4064	>	* @return the result of accumulating the given transformation
4065	>	* of all values
4066	>	* @since 1.8
4067	>	*/
4068	>	public <U> U reduceValues(long parallelismThreshold,
4069	>	Function<? super V, ? extends U> transformer,
4070	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4071	>	if (transformer == null || reducer == null)
4072	>	throw new NullPointerException();
4073	>	return new MapReduceValuesTask<K,V,U>
4074	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4075	>	null, transformer, reducer).invoke();
4076	>	}
4077	>
4078	>	/**
4079	>	* Returns the result of accumulating the given transformation
4080	>	* of all values using the given reducer to combine values,
4081	>	* and the given basis as an identity value.
4082	>	*
4083	>	* @param parallelismThreshold the (estimated) number of elements
4084	>	* needed for this operation to be executed in parallel
4085	>	* @param transformer a function returning the transformation
4086	>	* for an element
4087	>	* @param basis the identity (initial default value) for the reduction
4088	>	* @param reducer a commutative associative combining function
4089	>	* @return the result of accumulating the given transformation
4090	>	* of all values
4091	>	* @since 1.8
4092	>	*/
4093	>	public double reduceValuesToDouble(long parallelismThreshold,
4094	>	ToDoubleFunction<? super V> transformer,
4095	>	double basis,
4096	>	DoubleBinaryOperator reducer) {
4097	>	if (transformer == null || reducer == null)
4098	>	throw new NullPointerException();
4099	>	return new MapReduceValuesToDoubleTask<K,V>
4100	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4101	>	null, transformer, basis, reducer).invoke();
4102	>	}
4103	>
4104	>	/**
4105	>	* Returns the result of accumulating the given transformation
4106	>	* of all values using the given reducer to combine values,
4107	>	* and the given basis as an identity value.
4108	>	*
4109	>	* @param parallelismThreshold the (estimated) number of elements
4110	>	* needed for this operation to be executed in parallel
4111	>	* @param transformer a function returning the transformation
4112	>	* for an element
4113	>	* @param basis the identity (initial default value) for the reduction
4114	>	* @param reducer a commutative associative combining function
4115	>	* @return the result of accumulating the given transformation
4116	>	* of all values
4117	>	* @since 1.8
4118	>	*/
4119	>	public long reduceValuesToLong(long parallelismThreshold,
4120	>	ToLongFunction<? super V> transformer,
4121	>	long basis,
4122	>	LongBinaryOperator reducer) {
4123	>	if (transformer == null || reducer == null)
4124	>	throw new NullPointerException();
4125	>	return new MapReduceValuesToLongTask<K,V>
4126	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4127	>	null, transformer, basis, reducer).invoke();
4128	>	}
4129	>
4130	>	/**
4131	>	* Returns the result of accumulating the given transformation
4132	>	* of all values using the given reducer to combine values,
4133	>	* and the given basis as an identity value.
4134	>	*
4135	>	* @param parallelismThreshold the (estimated) number of elements
4136	>	* needed for this operation to be executed in parallel
4137	>	* @param transformer a function returning the transformation
4138	>	* for an element
4139	>	* @param basis the identity (initial default value) for the reduction
4140	>	* @param reducer a commutative associative combining function
4141	>	* @return the result of accumulating the given transformation
4142	>	* of all values
4143	>	* @since 1.8
4144	>	*/
4145	>	public int reduceValuesToInt(long parallelismThreshold,
4146	>	ToIntFunction<? super V> transformer,
4147	>	int basis,
4148	>	IntBinaryOperator reducer) {
4149	>	if (transformer == null || reducer == null)
4150	>	throw new NullPointerException();
4151	>	return new MapReduceValuesToIntTask<K,V>
4152	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4153	>	null, transformer, basis, reducer).invoke();
4154	>	}
4155	>
4156	>	/**
4157	>	* Performs the given action for each entry.
4158	>	*
4159	>	* @param parallelismThreshold the (estimated) number of elements
4160	>	* needed for this operation to be executed in parallel
4161	>	* @param action the action
4162	>	* @since 1.8
4163	>	*/
4164	>	public void forEachEntry(long parallelismThreshold,
4165	>	Consumer<? super Map.Entry<K,V>> action) {
4166	>	if (action == null) throw new NullPointerException();
4167	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4168	>	action).invoke();
4169	>	}
4170	>
4171	>	/**
4172	>	* Performs the given action for each non-null transformation
4173	>	* of each entry.
4174	>	*
4175	>	* @param parallelismThreshold the (estimated) number of elements
4176	>	* needed for this operation to be executed in parallel
4177	>	* @param transformer a function returning the transformation
4178	>	* for an element, or null if there is no transformation (in
4179	>	* which case the action is not applied)
4180	>	* @param action the action
4181	>	* @param <U> the return type of the transformer
4182	>	* @since 1.8
4183	>	*/
4184	>	public <U> void forEachEntry(long parallelismThreshold,
4185	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4186	>	Consumer<? super U> action) {
4187	>	if (transformer == null || action == null)
4188	>	throw new NullPointerException();
4189	>	new ForEachTransformedEntryTask<K,V,U>
4190	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4191	>	transformer, action).invoke();
4192	>	}
4193	>
4194	>	/**
4195	>	* Returns a non-null result from applying the given search
4196	>	* function on each entry, or null if none.  Upon success,
4197	>	* further element processing is suppressed and the results of
4198	>	* any other parallel invocations of the search function are
4199	>	* ignored.
4200	>	*
4201	>	* @param parallelismThreshold the (estimated) number of elements
4202	>	* needed for this operation to be executed in parallel
4203	>	* @param searchFunction a function returning a non-null
4204	>	* result on success, else null
4205	>	* @param <U> the return type of the search function
4206	>	* @return a non-null result from applying the given search
4207	>	* function on each entry, or null if none
4208	>	* @since 1.8
4209	>	*/
4210	>	public <U> U searchEntries(long parallelismThreshold,
4211	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4212	>	if (searchFunction == null) throw new NullPointerException();
4213	>	return new SearchEntriesTask<K,V,U>
4214	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4215	>	searchFunction, new AtomicReference<U>()).invoke();
4216	>	}
4217	>
4218	>	/**
4219	>	* Returns the result of accumulating all entries using the
4220	>	* given reducer to combine values, or null if none.
4221	>	*
4222	>	* @param parallelismThreshold the (estimated) number of elements
4223	>	* needed for this operation to be executed in parallel
4224	>	* @param reducer a commutative associative combining function
4225	>	* @return the result of accumulating all entries
4226	>	* @since 1.8
4227	>	*/
4228	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4229	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4230	>	if (reducer == null) throw new NullPointerException();
4231	>	return new ReduceEntriesTask<K,V>
4232	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4233	>	null, reducer).invoke();
4234	>	}
4235	>
4236	>	/**
4237	>	* Returns the result of accumulating the given transformation
4238	>	* of all entries using the given reducer to combine values,
4239	>	* or null if none.
4240	>	*
4241	>	* @param parallelismThreshold the (estimated) number of elements
4242	>	* needed for this operation to be executed in parallel
4243	>	* @param transformer a function returning the transformation
4244	>	* for an element, or null if there is no transformation (in
4245	>	* which case it is not combined)
4246	>	* @param reducer a commutative associative combining function
4247	>	* @param <U> the return type of the transformer
4248	>	* @return the result of accumulating the given transformation
4249	>	* of all entries
4250	>	* @since 1.8
4251	>	*/
4252	>	public <U> U reduceEntries(long parallelismThreshold,
4253	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4254	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4255	>	if (transformer == null || reducer == null)
4256	>	throw new NullPointerException();
4257	>	return new MapReduceEntriesTask<K,V,U>
4258	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4259	>	null, transformer, reducer).invoke();
4260	>	}
4261	>
4262	>	/**
4263	>	* Returns the result of accumulating the given transformation
4264	>	* of all entries using the given reducer to combine values,
4265	>	* and the given basis as an identity value.
4266	>	*
4267	>	* @param parallelismThreshold the (estimated) number of elements
4268	>	* needed for this operation to be executed in parallel
4269	>	* @param transformer a function returning the transformation
4270	>	* for an element
4271	>	* @param basis the identity (initial default value) for the reduction
4272	>	* @param reducer a commutative associative combining function
4273	>	* @return the result of accumulating the given transformation
4274	>	* of all entries
4275	>	* @since 1.8
4276	>	*/
4277	>	public double reduceEntriesToDouble(long parallelismThreshold,
4278	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4279	>	double basis,
4280	>	DoubleBinaryOperator reducer) {
4281	>	if (transformer == null || reducer == null)
4282	>	throw new NullPointerException();
4283	>	return new MapReduceEntriesToDoubleTask<K,V>
4284	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4285	>	null, transformer, basis, reducer).invoke();
4286	>	}
4287	>
4288	>	/**
4289	>	* Returns the result of accumulating the given transformation
4290	>	* of all entries using the given reducer to combine values,
4291	>	* and the given basis as an identity value.
4292	>	*
4293	>	* @param parallelismThreshold the (estimated) number of elements
4294	>	* needed for this operation to be executed in parallel
4295	>	* @param transformer a function returning the transformation
4296	>	* for an element
4297	>	* @param basis the identity (initial default value) for the reduction
4298	>	* @param reducer a commutative associative combining function
4299	>	* @return the result of accumulating the given transformation
4300	>	* of all entries
4301	>	* @since 1.8
4302	>	*/
4303	>	public long reduceEntriesToLong(long parallelismThreshold,
4304	>	ToLongFunction<Map.Entry<K,V>> transformer,
4305	>	long basis,
4306	>	LongBinaryOperator reducer) {
4307	>	if (transformer == null || reducer == null)
4308	>	throw new NullPointerException();
4309	>	return new MapReduceEntriesToLongTask<K,V>
4310	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4311	>	null, transformer, basis, reducer).invoke();
4312	>	}
4313	>
4314	>	/**
4315	>	* Returns the result of accumulating the given transformation
4316	>	* of all entries using the given reducer to combine values,
4317	>	* and the given basis as an identity value.
4318	>	*
4319	>	* @param parallelismThreshold the (estimated) number of elements
4320	>	* needed for this operation to be executed in parallel
4321	>	* @param transformer a function returning the transformation
4322	>	* for an element
4323	>	* @param basis the identity (initial default value) for the reduction
4324	>	* @param reducer a commutative associative combining function
4325	>	* @return the result of accumulating the given transformation
4326	>	* of all entries
4327	>	* @since 1.8
4328	>	*/
4329	>	public int reduceEntriesToInt(long parallelismThreshold,
4330	>	ToIntFunction<Map.Entry<K,V>> transformer,
4331	>	int basis,
4332	>	IntBinaryOperator reducer) {
4333	>	if (transformer == null || reducer == null)
4334	>	throw new NullPointerException();
4335	>	return new MapReduceEntriesToIntTask<K,V>
4336	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4337	>	null, transformer, basis, reducer).invoke();
4338	>	}
4339	>
4340	>
4341	>	/* ----------------Views -------------- */
4342	>
4343	>	/**
4344	>	* Base class for views.
4345	>	*/
4346	>	abstract static class CollectionView<K,V,E>
4347	>	implements Collection<E>, java.io.Serializable {
4348	>	private static final long serialVersionUID = 7249069246763182397L;
4349	>	final ConcurrentHashMap<K,V> map;
4350	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4351	>
4352	>	/**
4353	>	* Returns the map backing this view.
4354	>	*
4355	>	* @return the map backing this view
4356	>	*/
4357	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4358	>
4359	>	/**
4360	>	* Removes all of the elements from this view, by removing all
4361	>	* the mappings from the map backing this view.
4362	>	*/
4363	>	public final void clear()      { map.clear(); }
4364	>	public final int size()        { return map.size(); }
4365	>	public final boolean isEmpty() { return map.isEmpty(); }
4366	>
4367	>	// implementations below rely on concrete classes supplying these
4368	>	// abstract methods
4369	>	/**
4370	>	* Returns an iterator over the elements in this collection.
4371	>	*
4372	>	* <p>The returned iterator is
4373	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4374	>	*
4375	>	* @return an iterator over the elements in this collection
4376	>	*/
4377	>	public abstract Iterator<E> iterator();
4378	>	public abstract boolean contains(Object o);
4379	>	public abstract boolean remove(Object o);
4380	>
4381	>	private static final String oomeMsg = "Required array size too large";
4382	>
4383	>	public final Object[] toArray() {
4384	>	long sz = map.mappingCount();
4385	>	if (sz > MAX_ARRAY_SIZE)
4386	>	throw new OutOfMemoryError(oomeMsg);
4387	>	int n = (int)sz;
4388	>	Object[] r = new Object[n];
4389	>	int i = 0;
4390	>	for (E e : this) {
4391	>	if (i == n) {
4392	>	if (n >= MAX_ARRAY_SIZE)
4393	>	throw new OutOfMemoryError(oomeMsg);
4394	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4395	>	n = MAX_ARRAY_SIZE;
4396	>	else
4397	>	n += (n >>> 1) + 1;
4398	>	r = Arrays.copyOf(r, n);
4399	>	}
4400	>	r[i++] = e;
4401	>	}
4402	>	return (i == n) ? r : Arrays.copyOf(r, i);
4403		}
4404	<	public void clear() {
4405	<	ConcurrentHashMap.this.clear();
4404	>
4405	>	@SuppressWarnings("unchecked")
4406	>	public final <T> T[] toArray(T[] a) {
4407	>	long sz = map.mappingCount();
4408	>	if (sz > MAX_ARRAY_SIZE)
4409	>	throw new OutOfMemoryError(oomeMsg);
4410	>	int m = (int)sz;
4411	>	T[] r = (a.length >= m) ? a :
4412	>	(T[])java.lang.reflect.Array
4413	>	.newInstance(a.getClass().getComponentType(), m);
4414	>	int n = r.length;
4415	>	int i = 0;
4416	>	for (E e : this) {
4417	>	if (i == n) {
4418	>	if (n >= MAX_ARRAY_SIZE)
4419	>	throw new OutOfMemoryError(oomeMsg);
4420	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4421	>	n = MAX_ARRAY_SIZE;
4422	>	else
4423	>	n += (n >>> 1) + 1;
4424	>	r = Arrays.copyOf(r, n);
4425	>	}
4426	>	r[i++] = (T)e;
4427	>	}
4428	>	if (a == r && i < n) {
4429	>	r[i] = null; // null-terminate
4430	>	return r;
4431	>	}
4432	>	return (i == n) ? r : Arrays.copyOf(r, i);
4433		}
4434	<	public Object[] toArray() {
4435	<	Collection<K> c = new ArrayList<K>(size());
4436	<	for (K k : this)
4437	<	c.add(k);
4438	<	return c.toArray();
4434	>
4435	>	/**
4436	>	* Returns a string representation of this collection.
4437	>	* The string representation consists of the string representations
4438	>	* of the collection's elements in the order they are returned by
4439	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4440	>	* Adjacent elements are separated by the characters {@code ", "}
4441	>	* (comma and space).  Elements are converted to strings as by
4442	>	* {@link String#valueOf(Object)}.
4443	>	*
4444	>	* @return a string representation of this collection
4445	>	*/
4446	>	public final String toString() {
4447	>	StringBuilder sb = new StringBuilder();
4448	>	sb.append('[');
4449	>	Iterator<E> it = iterator();
4450	>	if (it.hasNext()) {
4451	>	for (;;) {
4452	>	Object e = it.next();
4453	>	sb.append(e == this ? "(this Collection)" : e);
4454	>	if (!it.hasNext())
4455	>	break;
4456	>	sb.append(',').append(' ');
4457	>	}
4458	>	}
4459	>	return sb.append(']').toString();
4460		}
4461	<	public <T> T[] toArray(T[] a) {
4462	<	Collection<K> c = new ArrayList<K>();
4463	<	for (K k : this)
4464	<	c.add(k);
4465	<	return c.toArray(a);
4461	>
4462	>	public final boolean containsAll(Collection<?> c) {
4463	>	if (c != this) {
4464	>	for (Object e : c) {
4465	>	if (e == null || !contains(e))
4466	>	return false;
4467	>	}
4468	>	}
4469	>	return true;
4470		}
1191	–	}
4471
4472	<	final class Values extends AbstractCollection<V> {
4473	<	public Iterator<V> iterator() {
4474	<	return new ValueIterator();
4472	>	public final boolean removeAll(Collection<?> c) {
4473	>	if (c == null) throw new NullPointerException();
4474	>	boolean modified = false;
4475	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4476	>	if (c.contains(it.next())) {
4477	>	it.remove();
4478	>	modified = true;
4479	>	}
4480	>	}
4481	>	return modified;
4482		}
4483	<	public int size() {
4484	<	return ConcurrentHashMap.this.size();
4483	>
4484	>	public final boolean retainAll(Collection<?> c) {
4485	>	if (c == null) throw new NullPointerException();
4486	>	boolean modified = false;
4487	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4488	>	if (!c.contains(it.next())) {
4489	>	it.remove();
4490	>	modified = true;
4491	>	}
4492	>	}
4493	>	return modified;
4494		}
4495	<	public boolean contains(Object o) {
4496	<	return ConcurrentHashMap.this.containsValue(o);
4495	>
4496	>	}
4497	>
4498	>	/**
4499	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4500	>	* which additions may optionally be enabled by mapping to a
4501	>	* common value.  This class cannot be directly instantiated.
4502	>	* See {@link #keySet() keySet()},
4503	>	* {@link #keySet(Object) keySet(V)},
4504	>	* {@link #newKeySet() newKeySet()},
4505	>	* {@link #newKeySet(int) newKeySet(int)}.
4506	>	*
4507	>	* @since 1.8
4508	>	*/
4509	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4510	>	implements Set<K>, java.io.Serializable {
4511	>	private static final long serialVersionUID = 7249069246763182397L;
4512	>	private final V value;
4513	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4514	>	super(map);
4515	>	this.value = value;
4516		}
4517	<	public void clear() {
4518	<	ConcurrentHashMap.this.clear();
4517	>
4518	>	/**
4519	>	* Returns the default mapped value for additions,
4520	>	* or {@code null} if additions are not supported.
4521	>	*
4522	>	* @return the default mapped value for additions, or {@code null}
4523	>	* if not supported
4524	>	*/
4525	>	public V getMappedValue() { return value; }
4526	>
4527	>	/**
4528	>	* {@inheritDoc}
4529	>	* @throws NullPointerException if the specified key is null
4530	>	*/
4531	>	public boolean contains(Object o) { return map.containsKey(o); }
4532	>
4533	>	/**
4534	>	* Removes the key from this map view, by removing the key (and its
4535	>	* corresponding value) from the backing map.  This method does
4536	>	* nothing if the key is not in the map.
4537	>	*
4538	>	* @param  o the key to be removed from the backing map
4539	>	* @return {@code true} if the backing map contained the specified key
4540	>	* @throws NullPointerException if the specified key is null
4541	>	*/
4542	>	public boolean remove(Object o) { return map.remove(o) != null; }
4543	>
4544	>	/**
4545	>	* @return an iterator over the keys of the backing map
4546	>	*/
4547	>	public Iterator<K> iterator() {
4548	>	Node<K,V>[] t;
4549	>	ConcurrentHashMap<K,V> m = map;
4550	>	int f = (t = m.table) == null ? 0 : t.length;
4551	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4552	>	}
4553	>
4554	>	/**
4555	>	* Adds the specified key to this set view by mapping the key to
4556	>	* the default mapped value in the backing map, if defined.
4557	>	*
4558	>	* @param e key to be added
4559	>	* @return {@code true} if this set changed as a result of the call
4560	>	* @throws NullPointerException if the specified key is null
4561	>	* @throws UnsupportedOperationException if no default mapped value
4562	>	* for additions was provided
4563	>	*/
4564	>	public boolean add(K e) {
4565	>	V v;
4566	>	if ((v = value) == null)
4567	>	throw new UnsupportedOperationException();
4568	>	return map.putVal(e, v, true) == null;
4569		}
4570	<	public Object[] toArray() {
4571	<	Collection<V> c = new ArrayList<V>(size());
4572	<	for (V v : this)
4573	<	c.add(v);
4574	<	return c.toArray();
4570	>
4571	>	/**
4572	>	* Adds all of the elements in the specified collection to this set,
4573	>	* as if by calling {@link #add} on each one.
4574	>	*
4575	>	* @param c the elements to be inserted into this set
4576	>	* @return {@code true} if this set changed as a result of the call
4577	>	* @throws NullPointerException if the collection or any of its
4578	>	* elements are {@code null}
4579	>	* @throws UnsupportedOperationException if no default mapped value
4580	>	* for additions was provided
4581	>	*/
4582	>	public boolean addAll(Collection<? extends K> c) {
4583	>	boolean added = false;
4584	>	V v;
4585	>	if ((v = value) == null)
4586	>	throw new UnsupportedOperationException();
4587	>	for (K e : c) {
4588	>	if (map.putVal(e, v, true) == null)
4589	>	added = true;
4590	>	}
4591	>	return added;
4592		}
4593	<	public <T> T[] toArray(T[] a) {
4594	<	Collection<V> c = new ArrayList<V>(size());
4595	<	for (V v : this)
4596	<	c.add(v);
4597	<	return c.toArray(a);
4593	>
4594	>	public int hashCode() {
4595	>	int h = 0;
4596	>	for (K e : this)
4597	>	h += e.hashCode();
4598	>	return h;
4599	>	}
4600	>
4601	>	public boolean equals(Object o) {
4602	>	Set<?> c;
4603	>	return ((o instanceof Set) &&
4604	>	((c = (Set<?>)o) == this ||
4605	>	(containsAll(c) && c.containsAll(this))));
4606	>	}
4607	>
4608	>	public Spliterator<K> spliterator() {
4609	>	Node<K,V>[] t;
4610	>	ConcurrentHashMap<K,V> m = map;
4611	>	long n = m.sumCount();
4612	>	int f = (t = m.table) == null ? 0 : t.length;
4613	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4614	>	}
4615	>
4616	>	public void forEach(Consumer<? super K> action) {
4617	>	if (action == null) throw new NullPointerException();
4618	>	Node<K,V>[] t;
4619	>	if ((t = map.table) != null) {
4620	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4621	>	for (Node<K,V> p; (p = it.advance()) != null; )
4622	>	action.accept(p.key);
4623	>	}
4624		}
4625		}
4626
4627	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4628	<	public Iterator<Map.Entry<K,V>> iterator() {
4629	<	return new EntryIterator();
4627	>	/**
4628	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4629	>	* values, in which additions are disabled. This class cannot be
4630	>	* directly instantiated. See {@link #values()}.
4631	>	*/
4632	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4633	>	implements Collection<V>, java.io.Serializable {
4634	>	private static final long serialVersionUID = 2249069246763182397L;
4635	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4636	>	public final boolean contains(Object o) {
4637	>	return map.containsValue(o);
4638	>	}
4639	>
4640	>	public final boolean remove(Object o) {
4641	>	if (o != null) {
4642	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4643	>	if (o.equals(it.next())) {
4644	>	it.remove();
4645	>	return true;
4646	>	}
4647	>	}
4648	>	}
4649	>	return false;
4650	>	}
4651	>
4652	>	public final Iterator<V> iterator() {
4653	>	ConcurrentHashMap<K,V> m = map;
4654	>	Node<K,V>[] t;
4655	>	int f = (t = m.table) == null ? 0 : t.length;
4656	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4657	>	}
4658	>
4659	>	public final boolean add(V e) {
4660	>	throw new UnsupportedOperationException();
4661	>	}
4662	>	public final boolean addAll(Collection<? extends V> c) {
4663	>	throw new UnsupportedOperationException();
4664	>	}
4665	>
4666	>	public Spliterator<V> spliterator() {
4667	>	Node<K,V>[] t;
4668	>	ConcurrentHashMap<K,V> m = map;
4669	>	long n = m.sumCount();
4670	>	int f = (t = m.table) == null ? 0 : t.length;
4671	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4672	>	}
4673	>
4674	>	public void forEach(Consumer<? super V> action) {
4675	>	if (action == null) throw new NullPointerException();
4676	>	Node<K,V>[] t;
4677	>	if ((t = map.table) != null) {
4678	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4679	>	for (Node<K,V> p; (p = it.advance()) != null; )
4680	>	action.accept(p.val);
4681	>	}
4682		}
4683	+	}
4684	+
4685	+	/**
4686	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4687	+	* entries.  This class cannot be directly instantiated. See
4688	+	* {@link #entrySet()}.
4689	+	*/
4690	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4691	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4692	+	private static final long serialVersionUID = 2249069246763182397L;
4693	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4694	+
4695		public boolean contains(Object o) {
4696	<	if (!(o instanceof Map.Entry))
4697	<	return false;
4698	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4699	<	V v = ConcurrentHashMap.this.get(e.getKey());
4700	<	return v != null && v.equals(e.getValue());
4696	>	Object k, v, r; Map.Entry<?,?> e;
4697	>	return ((o instanceof Map.Entry) &&
4698	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4699	>	(r = map.get(k)) != null &&
4700	>	(v = e.getValue()) != null &&
4701	>	(v == r || v.equals(r)));
4702		}
4703	+
4704		public boolean remove(Object o) {
4705	<	if (!(o instanceof Map.Entry))
4706	<	return false;
4707	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4708	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4705	>	Object k, v; Map.Entry<?,?> e;
4706	>	return ((o instanceof Map.Entry) &&
4707	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4708	>	(v = e.getValue()) != null &&
4709	>	map.remove(k, v));
4710		}
4711	<	public int size() {
4712	<	return ConcurrentHashMap.this.size();
4711	>
4712	>	/**
4713	>	* @return an iterator over the entries of the backing map
4714	>	*/
4715	>	public Iterator<Map.Entry<K,V>> iterator() {
4716	>	ConcurrentHashMap<K,V> m = map;
4717	>	Node<K,V>[] t;
4718	>	int f = (t = m.table) == null ? 0 : t.length;
4719	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4720		}
4721	<	public void clear() {
4722	<	ConcurrentHashMap.this.clear();
4721	>
4722	>	public boolean add(Entry<K,V> e) {
4723	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4724		}
4725	<	public Object[] toArray() {
4726	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
4727	<	for (Map.Entry<K,V> e : this)
4728	<	c.add(e);
4729	<	return c.toArray();
4725	>
4726	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4727	>	boolean added = false;
4728	>	for (Entry<K,V> e : c) {
4729	>	if (add(e))
4730	>	added = true;
4731	>	}
4732	>	return added;
4733	>	}
4734	>
4735	>	public final int hashCode() {
4736	>	int h = 0;
4737	>	Node<K,V>[] t;
4738	>	if ((t = map.table) != null) {
4739	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4740	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4741	>	h += p.hashCode();
4742	>	}
4743	>	}
4744	>	return h;
4745		}
4746	<	public <T> T[] toArray(T[] a) {
4747	<	Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>(size());
4748	<	for (Map.Entry<K,V> e : this)
4749	<	c.add(e);
4750	<	return c.toArray(a);
4746	>
4747	>	public final boolean equals(Object o) {
4748	>	Set<?> c;
4749	>	return ((o instanceof Set) &&
4750	>	((c = (Set<?>)o) == this ||
4751	>	(containsAll(c) && c.containsAll(this))));
4752	>	}
4753	>
4754	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4755	>	Node<K,V>[] t;
4756	>	ConcurrentHashMap<K,V> m = map;
4757	>	long n = m.sumCount();
4758	>	int f = (t = m.table) == null ? 0 : t.length;
4759	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4760	>	}
4761	>
4762	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4763	>	if (action == null) throw new NullPointerException();
4764	>	Node<K,V>[] t;
4765	>	if ((t = map.table) != null) {
4766	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4767	>	for (Node<K,V> p; (p = it.advance()) != null; )
4768	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4769	>	}
4770		}
4771
4772		}
4773
4774	<	/* ---------------- Serialization Support -------------- */
4774	>	// -------------------------------------------------------
4775
4776		/**
4777	<	* Save the state of the <tt>ConcurrentHashMap</tt> instance to a
4778	<	* stream (i.e., serialize it).
1263	<	* @param s the stream
1264	<	* @serialData
1265	<	* the key (Object) and value (Object)
1266	<	* for each key-value mapping, followed by a null pair.
1267	<	* The key-value mappings are emitted in no particular order.
4777	>	* Base class for bulk tasks. Repeats some fields and code from
4778	>	* class Traverser, because we need to subclass CountedCompleter.
4779		*/
4780	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
4781	<	s.defaultWriteObject();
4780	>	@SuppressWarnings("serial")
4781	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4782	>	Node<K,V>[] tab;        // same as Traverser
4783	>	Node<K,V> next;
4784	>	TableStack<K,V> stack, spare;
4785	>	int index;
4786	>	int baseIndex;
4787	>	int baseLimit;
4788	>	final int baseSize;
4789	>	int batch;              // split control
4790	>
4791	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4792	>	super(par);
4793	>	this.batch = b;
4794	>	this.index = this.baseIndex = i;
4795	>	if ((this.tab = t) == null)
4796	>	this.baseSize = this.baseLimit = 0;
4797	>	else if (par == null)
4798	>	this.baseSize = this.baseLimit = t.length;
4799	>	else {
4800	>	this.baseLimit = f;
4801	>	this.baseSize = par.baseSize;
4802	>	}
4803	>	}
4804
4805	<	for (int k = 0; k < segments.length; ++k) {
4806	<	Segment<K,V> seg = segments[k];
4807	<	seg.lock();
4808	<	try {
4809	<	HashEntry<K,V>[] tab = seg.table;
4810	<	for (int i = 0; i < tab.length; ++i) {
4811	<	for (HashEntry<K,V> e = tab[i]; e != null; e = e.next) {
4812	<	s.writeObject(e.key);
4813	<	s.writeObject(e.value);
4805	>	/**
4806	>	* Same as Traverser version
4807	>	*/
4808	>	final Node<K,V> advance() {
4809	>	Node<K,V> e;
4810	>	if ((e = next) != null)
4811	>	e = e.next;
4812	>	for (;;) {
4813	>	Node<K,V>[] t; int i, n;
4814	>	if (e != null)
4815	>	return next = e;
4816	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4817	>	(n = t.length) <= (i = index) || i < 0)
4818	>	return next = null;
4819	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4820	>	if (e instanceof ForwardingNode) {
4821	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4822	>	e = null;
4823	>	pushState(t, i, n);
4824	>	continue;
4825		}
4826	+	else if (e instanceof TreeBin)
4827	+	e = ((TreeBin<K,V>)e).first;
4828	+	else
4829	+	e = null;
4830		}
4831	<	} finally {
4832	<	seg.unlock();
4831	>	if (stack != null)
4832	>	recoverState(n);
4833	>	else if ((index = i + baseSize) >= n)
4834	>	index = ++baseIndex;
4835		}
4836		}
4837	<	s.writeObject(null);
4838	<	s.writeObject(null);
4837	>
4838	>	private void pushState(Node<K,V>[] t, int i, int n) {
4839	>	TableStack<K,V> s = spare;
4840	>	if (s != null)
4841	>	spare = s.next;
4842	>	else
4843	>	s = new TableStack<K,V>();
4844	>	s.tab = t;
4845	>	s.length = n;
4846	>	s.index = i;
4847	>	s.next = stack;
4848	>	stack = s;
4849	>	}
4850	>
4851	>	private void recoverState(int n) {
4852	>	TableStack<K,V> s; int len;
4853	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4854	>	n = len;
4855	>	index = s.index;
4856	>	tab = s.tab;
4857	>	s.tab = null;
4858	>	TableStack<K,V> next = s.next;
4859	>	s.next = spare; // save for reuse
4860	>	stack = next;
4861	>	spare = s;
4862	>	}
4863	>	if (s == null && (index += baseSize) >= n)
4864	>	index = ++baseIndex;
4865	>	}
4866		}
4867
4868	<	/**
4869	<	* Reconstitute the <tt>ConcurrentHashMap</tt> instance from a
4870	<	* stream (i.e., deserialize it).
4871	<	* @param s the stream
4872	<	*/
4873	<	private void readObject(java.io.ObjectInputStream s)
4874	<	throws IOException, ClassNotFoundException  {
4875	<	s.defaultReadObject();
4868	>	/*
4869	>	* Task classes. Coded in a regular but ugly format/style to
4870	>	* simplify checks that each variant differs in the right way from
4871	>	* others. The null screenings exist because compilers cannot tell
4872	>	* that we've already null-checked task arguments, so we force
4873	>	* simplest hoisted bypass to help avoid convoluted traps.
4874	>	*/
4875	>	@SuppressWarnings("serial")
4876	>	static final class ForEachKeyTask<K,V>
4877	>	extends BulkTask<K,V,Void> {
4878	>	final Consumer<? super K> action;
4879	>	ForEachKeyTask
4880	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4881	>	Consumer<? super K> action) {
4882	>	super(p, b, i, f, t);
4883	>	this.action = action;
4884	>	}
4885	>	public final void compute() {
4886	>	final Consumer<? super K> action;
4887	>	if ((action = this.action) != null) {
4888	>	for (int i = baseIndex, f, h; batch > 0 &&
4889	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4890	>	addToPendingCount(1);
4891	>	new ForEachKeyTask<K,V>
4892	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4893	>	action).fork();
4894	>	}
4895	>	for (Node<K,V> p; (p = advance()) != null;)
4896	>	action.accept(p.key);
4897	>	propagateCompletion();
4898	>	}
4899	>	}
4900	>	}
4901
4902	<	// Initialize each segment to be minimally sized, and let grow.
4903	<	for (int i = 0; i < segments.length; ++i) {
4904	<	segments[i].setTable(new HashEntry[1]);
4902	>	@SuppressWarnings("serial")
4903	>	static final class ForEachValueTask<K,V>
4904	>	extends BulkTask<K,V,Void> {
4905	>	final Consumer<? super V> action;
4906	>	ForEachValueTask
4907	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4908	>	Consumer<? super V> action) {
4909	>	super(p, b, i, f, t);
4910	>	this.action = action;
4911	>	}
4912	>	public final void compute() {
4913	>	final Consumer<? super V> action;
4914	>	if ((action = this.action) != null) {
4915	>	for (int i = baseIndex, f, h; batch > 0 &&
4916	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4917	>	addToPendingCount(1);
4918	>	new ForEachValueTask<K,V>
4919	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4920	>	action).fork();
4921	>	}
4922	>	for (Node<K,V> p; (p = advance()) != null;)
4923	>	action.accept(p.val);
4924	>	propagateCompletion();
4925	>	}
4926		}
4927	+	}
4928
4929	<	// Read the keys and values, and put the mappings in the table
4930	<	for (;;) {
4931	<	K key = (K) s.readObject();
4932	<	V value = (V) s.readObject();
4933	<	if (key == null)
4934	<	break;
4935	<	put(key, value);
4929	>	@SuppressWarnings("serial")
4930	>	static final class ForEachEntryTask<K,V>
4931	>	extends BulkTask<K,V,Void> {
4932	>	final Consumer<? super Entry<K,V>> action;
4933	>	ForEachEntryTask
4934	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4935	>	Consumer<? super Entry<K,V>> action) {
4936	>	super(p, b, i, f, t);
4937	>	this.action = action;
4938	>	}
4939	>	public final void compute() {
4940	>	final Consumer<? super Entry<K,V>> action;
4941	>	if ((action = this.action) != null) {
4942	>	for (int i = baseIndex, f, h; batch > 0 &&
4943	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4944	>	addToPendingCount(1);
4945	>	new ForEachEntryTask<K,V>
4946	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4947	>	action).fork();
4948	>	}
4949	>	for (Node<K,V> p; (p = advance()) != null; )
4950	>	action.accept(p);
4951	>	propagateCompletion();
4952	>	}
4953	>	}
4954	>	}
4955	>
4956	>	@SuppressWarnings("serial")
4957	>	static final class ForEachMappingTask<K,V>
4958	>	extends BulkTask<K,V,Void> {
4959	>	final BiConsumer<? super K, ? super V> action;
4960	>	ForEachMappingTask
4961	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4962	>	BiConsumer<? super K,? super V> action) {
4963	>	super(p, b, i, f, t);
4964	>	this.action = action;
4965	>	}
4966	>	public final void compute() {
4967	>	final BiConsumer<? super K, ? super V> action;
4968	>	if ((action = this.action) != null) {
4969	>	for (int i = baseIndex, f, h; batch > 0 &&
4970	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4971	>	addToPendingCount(1);
4972	>	new ForEachMappingTask<K,V>
4973	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4974	>	action).fork();
4975	>	}
4976	>	for (Node<K,V> p; (p = advance()) != null; )
4977	>	action.accept(p.key, p.val);
4978	>	propagateCompletion();
4979	>	}
4980	>	}
4981	>	}
4982	>
4983	>	@SuppressWarnings("serial")
4984	>	static final class ForEachTransformedKeyTask<K,V,U>
4985	>	extends BulkTask<K,V,Void> {
4986	>	final Function<? super K, ? extends U> transformer;
4987	>	final Consumer<? super U> action;
4988	>	ForEachTransformedKeyTask
4989	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4990	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4991	>	super(p, b, i, f, t);
4992	>	this.transformer = transformer; this.action = action;
4993	>	}
4994	>	public final void compute() {
4995	>	final Function<? super K, ? extends U> transformer;
4996	>	final Consumer<? super U> action;
4997	>	if ((transformer = this.transformer) != null &&
4998	>	(action = this.action) != null) {
4999	>	for (int i = baseIndex, f, h; batch > 0 &&
5000	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5001	>	addToPendingCount(1);
5002	>	new ForEachTransformedKeyTask<K,V,U>
5003	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5004	>	transformer, action).fork();
5005	>	}
5006	>	for (Node<K,V> p; (p = advance()) != null; ) {
5007	>	U u;
5008	>	if ((u = transformer.apply(p.key)) != null)
5009	>	action.accept(u);
5010	>	}
5011	>	propagateCompletion();
5012	>	}
5013	>	}
5014	>	}
5015	>
5016	>	@SuppressWarnings("serial")
5017	>	static final class ForEachTransformedValueTask<K,V,U>
5018	>	extends BulkTask<K,V,Void> {
5019	>	final Function<? super V, ? extends U> transformer;
5020	>	final Consumer<? super U> action;
5021	>	ForEachTransformedValueTask
5022	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5023	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5024	>	super(p, b, i, f, t);
5025	>	this.transformer = transformer; this.action = action;
5026	>	}
5027	>	public final void compute() {
5028	>	final Function<? super V, ? extends U> transformer;
5029	>	final Consumer<? super U> action;
5030	>	if ((transformer = this.transformer) != null &&
5031	>	(action = this.action) != null) {
5032	>	for (int i = baseIndex, f, h; batch > 0 &&
5033	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5034	>	addToPendingCount(1);
5035	>	new ForEachTransformedValueTask<K,V,U>
5036	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5037	>	transformer, action).fork();
5038	>	}
5039	>	for (Node<K,V> p; (p = advance()) != null; ) {
5040	>	U u;
5041	>	if ((u = transformer.apply(p.val)) != null)
5042	>	action.accept(u);
5043	>	}
5044	>	propagateCompletion();
5045	>	}
5046	>	}
5047	>	}
5048	>
5049	>	@SuppressWarnings("serial")
5050	>	static final class ForEachTransformedEntryTask<K,V,U>
5051	>	extends BulkTask<K,V,Void> {
5052	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5053	>	final Consumer<? super U> action;
5054	>	ForEachTransformedEntryTask
5055	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5056	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5057	>	super(p, b, i, f, t);
5058	>	this.transformer = transformer; this.action = action;
5059	>	}
5060	>	public final void compute() {
5061	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5062	>	final Consumer<? super U> action;
5063	>	if ((transformer = this.transformer) != null &&
5064	>	(action = this.action) != null) {
5065	>	for (int i = baseIndex, f, h; batch > 0 &&
5066	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5067	>	addToPendingCount(1);
5068	>	new ForEachTransformedEntryTask<K,V,U>
5069	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5070	>	transformer, action).fork();
5071	>	}
5072	>	for (Node<K,V> p; (p = advance()) != null; ) {
5073	>	U u;
5074	>	if ((u = transformer.apply(p)) != null)
5075	>	action.accept(u);
5076	>	}
5077	>	propagateCompletion();
5078	>	}
5079	>	}
5080	>	}
5081	>
5082	>	@SuppressWarnings("serial")
5083	>	static final class ForEachTransformedMappingTask<K,V,U>
5084	>	extends BulkTask<K,V,Void> {
5085	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5086	>	final Consumer<? super U> action;
5087	>	ForEachTransformedMappingTask
5088	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5089	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5090	>	Consumer<? super U> action) {
5091	>	super(p, b, i, f, t);
5092	>	this.transformer = transformer; this.action = action;
5093	>	}
5094	>	public final void compute() {
5095	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5096	>	final Consumer<? super U> action;
5097	>	if ((transformer = this.transformer) != null &&
5098	>	(action = this.action) != null) {
5099	>	for (int i = baseIndex, f, h; batch > 0 &&
5100	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5101	>	addToPendingCount(1);
5102	>	new ForEachTransformedMappingTask<K,V,U>
5103	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5104	>	transformer, action).fork();
5105	>	}
5106	>	for (Node<K,V> p; (p = advance()) != null; ) {
5107	>	U u;
5108	>	if ((u = transformer.apply(p.key, p.val)) != null)
5109	>	action.accept(u);
5110	>	}
5111	>	propagateCompletion();
5112	>	}
5113	>	}
5114	>	}
5115	>
5116	>	@SuppressWarnings("serial")
5117	>	static final class SearchKeysTask<K,V,U>
5118	>	extends BulkTask<K,V,U> {
5119	>	final Function<? super K, ? extends U> searchFunction;
5120	>	final AtomicReference<U> result;
5121	>	SearchKeysTask
5122	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5123	>	Function<? super K, ? extends U> searchFunction,
5124	>	AtomicReference<U> result) {
5125	>	super(p, b, i, f, t);
5126	>	this.searchFunction = searchFunction; this.result = result;
5127	>	}
5128	>	public final U getRawResult() { return result.get(); }
5129	>	public final void compute() {
5130	>	final Function<? super K, ? extends U> searchFunction;
5131	>	final AtomicReference<U> result;
5132	>	if ((searchFunction = this.searchFunction) != null &&
5133	>	(result = this.result) != null) {
5134	>	for (int i = baseIndex, f, h; batch > 0 &&
5135	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5136	>	if (result.get() != null)
5137	>	return;
5138	>	addToPendingCount(1);
5139	>	new SearchKeysTask<K,V,U>
5140	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5141	>	searchFunction, result).fork();
5142	>	}
5143	>	while (result.get() == null) {
5144	>	U u;
5145	>	Node<K,V> p;
5146	>	if ((p = advance()) == null) {
5147	>	propagateCompletion();
5148	>	break;
5149	>	}
5150	>	if ((u = searchFunction.apply(p.key)) != null) {
5151	>	if (result.compareAndSet(null, u))
5152	>	quietlyCompleteRoot();
5153	>	break;
5154	>	}
5155	>	}
5156	>	}
5157	>	}
5158	>	}
5159	>
5160	>	@SuppressWarnings("serial")
5161	>	static final class SearchValuesTask<K,V,U>
5162	>	extends BulkTask<K,V,U> {
5163	>	final Function<? super V, ? extends U> searchFunction;
5164	>	final AtomicReference<U> result;
5165	>	SearchValuesTask
5166	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5167	>	Function<? super V, ? extends U> searchFunction,
5168	>	AtomicReference<U> result) {
5169	>	super(p, b, i, f, t);
5170	>	this.searchFunction = searchFunction; this.result = result;
5171	>	}
5172	>	public final U getRawResult() { return result.get(); }
5173	>	public final void compute() {
5174	>	final Function<? super V, ? extends U> searchFunction;
5175	>	final AtomicReference<U> result;
5176	>	if ((searchFunction = this.searchFunction) != null &&
5177	>	(result = this.result) != null) {
5178	>	for (int i = baseIndex, f, h; batch > 0 &&
5179	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5180	>	if (result.get() != null)
5181	>	return;
5182	>	addToPendingCount(1);
5183	>	new SearchValuesTask<K,V,U>
5184	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5185	>	searchFunction, result).fork();
5186	>	}
5187	>	while (result.get() == null) {
5188	>	U u;
5189	>	Node<K,V> p;
5190	>	if ((p = advance()) == null) {
5191	>	propagateCompletion();
5192	>	break;
5193	>	}
5194	>	if ((u = searchFunction.apply(p.val)) != null) {
5195	>	if (result.compareAndSet(null, u))
5196	>	quietlyCompleteRoot();
5197	>	break;
5198	>	}
5199	>	}
5200	>	}
5201	>	}
5202	>	}
5203	>
5204	>	@SuppressWarnings("serial")
5205	>	static final class SearchEntriesTask<K,V,U>
5206	>	extends BulkTask<K,V,U> {
5207	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5208	>	final AtomicReference<U> result;
5209	>	SearchEntriesTask
5210	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5211	>	Function<Entry<K,V>, ? extends U> searchFunction,
5212	>	AtomicReference<U> result) {
5213	>	super(p, b, i, f, t);
5214	>	this.searchFunction = searchFunction; this.result = result;
5215	>	}
5216	>	public final U getRawResult() { return result.get(); }
5217	>	public final void compute() {
5218	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5219	>	final AtomicReference<U> result;
5220	>	if ((searchFunction = this.searchFunction) != null &&
5221	>	(result = this.result) != null) {
5222	>	for (int i = baseIndex, f, h; batch > 0 &&
5223	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5224	>	if (result.get() != null)
5225	>	return;
5226	>	addToPendingCount(1);
5227	>	new SearchEntriesTask<K,V,U>
5228	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5229	>	searchFunction, result).fork();
5230	>	}
5231	>	while (result.get() == null) {
5232	>	U u;
5233	>	Node<K,V> p;
5234	>	if ((p = advance()) == null) {
5235	>	propagateCompletion();
5236	>	break;
5237	>	}
5238	>	if ((u = searchFunction.apply(p)) != null) {
5239	>	if (result.compareAndSet(null, u))
5240	>	quietlyCompleteRoot();
5241	>	return;
5242	>	}
5243	>	}
5244	>	}
5245	>	}
5246	>	}
5247	>
5248	>	@SuppressWarnings("serial")
5249	>	static final class SearchMappingsTask<K,V,U>
5250	>	extends BulkTask<K,V,U> {
5251	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5252	>	final AtomicReference<U> result;
5253	>	SearchMappingsTask
5254	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5255	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5256	>	AtomicReference<U> result) {
5257	>	super(p, b, i, f, t);
5258	>	this.searchFunction = searchFunction; this.result = result;
5259	>	}
5260	>	public final U getRawResult() { return result.get(); }
5261	>	public final void compute() {
5262	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5263	>	final AtomicReference<U> result;
5264	>	if ((searchFunction = this.searchFunction) != null &&
5265	>	(result = this.result) != null) {
5266	>	for (int i = baseIndex, f, h; batch > 0 &&
5267	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5268	>	if (result.get() != null)
5269	>	return;
5270	>	addToPendingCount(1);
5271	>	new SearchMappingsTask<K,V,U>
5272	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5273	>	searchFunction, result).fork();
5274	>	}
5275	>	while (result.get() == null) {
5276	>	U u;
5277	>	Node<K,V> p;
5278	>	if ((p = advance()) == null) {
5279	>	propagateCompletion();
5280	>	break;
5281	>	}
5282	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5283	>	if (result.compareAndSet(null, u))
5284	>	quietlyCompleteRoot();
5285	>	break;
5286	>	}
5287	>	}
5288	>	}
5289	>	}
5290	>	}
5291	>
5292	>	@SuppressWarnings("serial")
5293	>	static final class ReduceKeysTask<K,V>
5294	>	extends BulkTask<K,V,K> {
5295	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5296	>	K result;
5297	>	ReduceKeysTask<K,V> rights, nextRight;
5298	>	ReduceKeysTask
5299	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5300	>	ReduceKeysTask<K,V> nextRight,
5301	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5302	>	super(p, b, i, f, t); this.nextRight = nextRight;
5303	>	this.reducer = reducer;
5304	>	}
5305	>	public final K getRawResult() { return result; }
5306	>	public final void compute() {
5307	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5308	>	if ((reducer = this.reducer) != null) {
5309	>	for (int i = baseIndex, f, h; batch > 0 &&
5310	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5311	>	addToPendingCount(1);
5312	>	(rights = new ReduceKeysTask<K,V>
5313	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5314	>	rights, reducer)).fork();
5315	>	}
5316	>	K r = null;
5317	>	for (Node<K,V> p; (p = advance()) != null; ) {
5318	>	K u = p.key;
5319	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5320	>	}
5321	>	result = r;
5322	>	CountedCompleter<?> c;
5323	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5324	>	@SuppressWarnings("unchecked")
5325	>	ReduceKeysTask<K,V>
5326	>	t = (ReduceKeysTask<K,V>)c,
5327	>	s = t.rights;
5328	>	while (s != null) {
5329	>	K tr, sr;
5330	>	if ((sr = s.result) != null)
5331	>	t.result = (((tr = t.result) == null) ? sr :
5332	>	reducer.apply(tr, sr));
5333	>	s = t.rights = s.nextRight;
5334	>	}
5335	>	}
5336	>	}
5337	>	}
5338	>	}
5339	>
5340	>	@SuppressWarnings("serial")
5341	>	static final class ReduceValuesTask<K,V>
5342	>	extends BulkTask<K,V,V> {
5343	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5344	>	V result;
5345	>	ReduceValuesTask<K,V> rights, nextRight;
5346	>	ReduceValuesTask
5347	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5348	>	ReduceValuesTask<K,V> nextRight,
5349	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5350	>	super(p, b, i, f, t); this.nextRight = nextRight;
5351	>	this.reducer = reducer;
5352	>	}
5353	>	public final V getRawResult() { return result; }
5354	>	public final void compute() {
5355	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5356	>	if ((reducer = this.reducer) != null) {
5357	>	for (int i = baseIndex, f, h; batch > 0 &&
5358	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5359	>	addToPendingCount(1);
5360	>	(rights = new ReduceValuesTask<K,V>
5361	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5362	>	rights, reducer)).fork();
5363	>	}
5364	>	V r = null;
5365	>	for (Node<K,V> p; (p = advance()) != null; ) {
5366	>	V v = p.val;
5367	>	r = (r == null) ? v : reducer.apply(r, v);
5368	>	}
5369	>	result = r;
5370	>	CountedCompleter<?> c;
5371	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5372	>	@SuppressWarnings("unchecked")
5373	>	ReduceValuesTask<K,V>
5374	>	t = (ReduceValuesTask<K,V>)c,
5375	>	s = t.rights;
5376	>	while (s != null) {
5377	>	V tr, sr;
5378	>	if ((sr = s.result) != null)
5379	>	t.result = (((tr = t.result) == null) ? sr :
5380	>	reducer.apply(tr, sr));
5381	>	s = t.rights = s.nextRight;
5382	>	}
5383	>	}
5384	>	}
5385	>	}
5386	>	}
5387	>
5388	>	@SuppressWarnings("serial")
5389	>	static final class ReduceEntriesTask<K,V>
5390	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5391	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5392	>	Map.Entry<K,V> result;
5393	>	ReduceEntriesTask<K,V> rights, nextRight;
5394	>	ReduceEntriesTask
5395	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5396	>	ReduceEntriesTask<K,V> nextRight,
5397	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5398	>	super(p, b, i, f, t); this.nextRight = nextRight;
5399	>	this.reducer = reducer;
5400	>	}
5401	>	public final Map.Entry<K,V> getRawResult() { return result; }
5402	>	public final void compute() {
5403	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5404	>	if ((reducer = this.reducer) != null) {
5405	>	for (int i = baseIndex, f, h; batch > 0 &&
5406	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5407	>	addToPendingCount(1);
5408	>	(rights = new ReduceEntriesTask<K,V>
5409	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5410	>	rights, reducer)).fork();
5411	>	}
5412	>	Map.Entry<K,V> r = null;
5413	>	for (Node<K,V> p; (p = advance()) != null; )
5414	>	r = (r == null) ? p : reducer.apply(r, p);
5415	>	result = r;
5416	>	CountedCompleter<?> c;
5417	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5418	>	@SuppressWarnings("unchecked")
5419	>	ReduceEntriesTask<K,V>
5420	>	t = (ReduceEntriesTask<K,V>)c,
5421	>	s = t.rights;
5422	>	while (s != null) {
5423	>	Map.Entry<K,V> tr, sr;
5424	>	if ((sr = s.result) != null)
5425	>	t.result = (((tr = t.result) == null) ? sr :
5426	>	reducer.apply(tr, sr));
5427	>	s = t.rights = s.nextRight;
5428	>	}
5429	>	}
5430	>	}
5431	>	}
5432	>	}
5433	>
5434	>	@SuppressWarnings("serial")
5435	>	static final class MapReduceKeysTask<K,V,U>
5436	>	extends BulkTask<K,V,U> {
5437	>	final Function<? super K, ? extends U> transformer;
5438	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5439	>	U result;
5440	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5441	>	MapReduceKeysTask
5442	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5443	>	MapReduceKeysTask<K,V,U> nextRight,
5444	>	Function<? super K, ? extends U> transformer,
5445	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5446	>	super(p, b, i, f, t); this.nextRight = nextRight;
5447	>	this.transformer = transformer;
5448	>	this.reducer = reducer;
5449	>	}
5450	>	public final U getRawResult() { return result; }
5451	>	public final void compute() {
5452	>	final Function<? super K, ? extends U> transformer;
5453	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5454	>	if ((transformer = this.transformer) != null &&
5455	>	(reducer = this.reducer) != null) {
5456	>	for (int i = baseIndex, f, h; batch > 0 &&
5457	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5458	>	addToPendingCount(1);
5459	>	(rights = new MapReduceKeysTask<K,V,U>
5460	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5461	>	rights, transformer, reducer)).fork();
5462	>	}
5463	>	U r = null;
5464	>	for (Node<K,V> p; (p = advance()) != null; ) {
5465	>	U u;
5466	>	if ((u = transformer.apply(p.key)) != null)
5467	>	r = (r == null) ? u : reducer.apply(r, u);
5468	>	}
5469	>	result = r;
5470	>	CountedCompleter<?> c;
5471	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5472	>	@SuppressWarnings("unchecked")
5473	>	MapReduceKeysTask<K,V,U>
5474	>	t = (MapReduceKeysTask<K,V,U>)c,
5475	>	s = t.rights;
5476	>	while (s != null) {
5477	>	U tr, sr;
5478	>	if ((sr = s.result) != null)
5479	>	t.result = (((tr = t.result) == null) ? sr :
5480	>	reducer.apply(tr, sr));
5481	>	s = t.rights = s.nextRight;
5482	>	}
5483	>	}
5484	>	}
5485	>	}
5486	>	}
5487	>
5488	>	@SuppressWarnings("serial")
5489	>	static final class MapReduceValuesTask<K,V,U>
5490	>	extends BulkTask<K,V,U> {
5491	>	final Function<? super V, ? extends U> transformer;
5492	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5493	>	U result;
5494	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5495	>	MapReduceValuesTask
5496	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5497	>	MapReduceValuesTask<K,V,U> nextRight,
5498	>	Function<? super V, ? extends U> transformer,
5499	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5500	>	super(p, b, i, f, t); this.nextRight = nextRight;
5501	>	this.transformer = transformer;
5502	>	this.reducer = reducer;
5503	>	}
5504	>	public final U getRawResult() { return result; }
5505	>	public final void compute() {
5506	>	final Function<? super V, ? extends U> transformer;
5507	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5508	>	if ((transformer = this.transformer) != null &&
5509	>	(reducer = this.reducer) != null) {
5510	>	for (int i = baseIndex, f, h; batch > 0 &&
5511	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5512	>	addToPendingCount(1);
5513	>	(rights = new MapReduceValuesTask<K,V,U>
5514	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5515	>	rights, transformer, reducer)).fork();
5516	>	}
5517	>	U r = null;
5518	>	for (Node<K,V> p; (p = advance()) != null; ) {
5519	>	U u;
5520	>	if ((u = transformer.apply(p.val)) != null)
5521	>	r = (r == null) ? u : reducer.apply(r, u);
5522	>	}
5523	>	result = r;
5524	>	CountedCompleter<?> c;
5525	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5526	>	@SuppressWarnings("unchecked")
5527	>	MapReduceValuesTask<K,V,U>
5528	>	t = (MapReduceValuesTask<K,V,U>)c,
5529	>	s = t.rights;
5530	>	while (s != null) {
5531	>	U tr, sr;
5532	>	if ((sr = s.result) != null)
5533	>	t.result = (((tr = t.result) == null) ? sr :
5534	>	reducer.apply(tr, sr));
5535	>	s = t.rights = s.nextRight;
5536	>	}
5537	>	}
5538	>	}
5539	>	}
5540	>	}
5541	>
5542	>	@SuppressWarnings("serial")
5543	>	static final class MapReduceEntriesTask<K,V,U>
5544	>	extends BulkTask<K,V,U> {
5545	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5546	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5547	>	U result;
5548	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5549	>	MapReduceEntriesTask
5550	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5551	>	MapReduceEntriesTask<K,V,U> nextRight,
5552	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5553	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5554	>	super(p, b, i, f, t); this.nextRight = nextRight;
5555	>	this.transformer = transformer;
5556	>	this.reducer = reducer;
5557	>	}
5558	>	public final U getRawResult() { return result; }
5559	>	public final void compute() {
5560	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5561	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5562	>	if ((transformer = this.transformer) != null &&
5563	>	(reducer = this.reducer) != null) {
5564	>	for (int i = baseIndex, f, h; batch > 0 &&
5565	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5566	>	addToPendingCount(1);
5567	>	(rights = new MapReduceEntriesTask<K,V,U>
5568	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5569	>	rights, transformer, reducer)).fork();
5570	>	}
5571	>	U r = null;
5572	>	for (Node<K,V> p; (p = advance()) != null; ) {
5573	>	U u;
5574	>	if ((u = transformer.apply(p)) != null)
5575	>	r = (r == null) ? u : reducer.apply(r, u);
5576	>	}
5577	>	result = r;
5578	>	CountedCompleter<?> c;
5579	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5580	>	@SuppressWarnings("unchecked")
5581	>	MapReduceEntriesTask<K,V,U>
5582	>	t = (MapReduceEntriesTask<K,V,U>)c,
5583	>	s = t.rights;
5584	>	while (s != null) {
5585	>	U tr, sr;
5586	>	if ((sr = s.result) != null)
5587	>	t.result = (((tr = t.result) == null) ? sr :
5588	>	reducer.apply(tr, sr));
5589	>	s = t.rights = s.nextRight;
5590	>	}
5591	>	}
5592	>	}
5593	>	}
5594	>	}
5595	>
5596	>	@SuppressWarnings("serial")
5597	>	static final class MapReduceMappingsTask<K,V,U>
5598	>	extends BulkTask<K,V,U> {
5599	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5600	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5601	>	U result;
5602	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5603	>	MapReduceMappingsTask
5604	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5605	>	MapReduceMappingsTask<K,V,U> nextRight,
5606	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5607	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5608	>	super(p, b, i, f, t); this.nextRight = nextRight;
5609	>	this.transformer = transformer;
5610	>	this.reducer = reducer;
5611	>	}
5612	>	public final U getRawResult() { return result; }
5613	>	public final void compute() {
5614	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5615	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5616	>	if ((transformer = this.transformer) != null &&
5617	>	(reducer = this.reducer) != null) {
5618	>	for (int i = baseIndex, f, h; batch > 0 &&
5619	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5620	>	addToPendingCount(1);
5621	>	(rights = new MapReduceMappingsTask<K,V,U>
5622	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5623	>	rights, transformer, reducer)).fork();
5624	>	}
5625	>	U r = null;
5626	>	for (Node<K,V> p; (p = advance()) != null; ) {
5627	>	U u;
5628	>	if ((u = transformer.apply(p.key, p.val)) != null)
5629	>	r = (r == null) ? u : reducer.apply(r, u);
5630	>	}
5631	>	result = r;
5632	>	CountedCompleter<?> c;
5633	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5634	>	@SuppressWarnings("unchecked")
5635	>	MapReduceMappingsTask<K,V,U>
5636	>	t = (MapReduceMappingsTask<K,V,U>)c,
5637	>	s = t.rights;
5638	>	while (s != null) {
5639	>	U tr, sr;
5640	>	if ((sr = s.result) != null)
5641	>	t.result = (((tr = t.result) == null) ? sr :
5642	>	reducer.apply(tr, sr));
5643	>	s = t.rights = s.nextRight;
5644	>	}
5645	>	}
5646	>	}
5647	>	}
5648	>	}
5649	>
5650	>	@SuppressWarnings("serial")
5651	>	static final class MapReduceKeysToDoubleTask<K,V>
5652	>	extends BulkTask<K,V,Double> {
5653	>	final ToDoubleFunction<? super K> transformer;
5654	>	final DoubleBinaryOperator reducer;
5655	>	final double basis;
5656	>	double result;
5657	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5658	>	MapReduceKeysToDoubleTask
5659	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5660	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5661	>	ToDoubleFunction<? super K> transformer,
5662	>	double basis,
5663	>	DoubleBinaryOperator reducer) {
5664	>	super(p, b, i, f, t); this.nextRight = nextRight;
5665	>	this.transformer = transformer;
5666	>	this.basis = basis; this.reducer = reducer;
5667	>	}
5668	>	public final Double getRawResult() { return result; }
5669	>	public final void compute() {
5670	>	final ToDoubleFunction<? super K> transformer;
5671	>	final DoubleBinaryOperator reducer;
5672	>	if ((transformer = this.transformer) != null &&
5673	>	(reducer = this.reducer) != null) {
5674	>	double r = this.basis;
5675	>	for (int i = baseIndex, f, h; batch > 0 &&
5676	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5677	>	addToPendingCount(1);
5678	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5679	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5680	>	rights, transformer, r, reducer)).fork();
5681	>	}
5682	>	for (Node<K,V> p; (p = advance()) != null; )
5683	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5684	>	result = r;
5685	>	CountedCompleter<?> c;
5686	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5687	>	@SuppressWarnings("unchecked")
5688	>	MapReduceKeysToDoubleTask<K,V>
5689	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5690	>	s = t.rights;
5691	>	while (s != null) {
5692	>	t.result = reducer.applyAsDouble(t.result, s.result);
5693	>	s = t.rights = s.nextRight;
5694	>	}
5695	>	}
5696	>	}
5697	>	}
5698	>	}
5699	>
5700	>	@SuppressWarnings("serial")
5701	>	static final class MapReduceValuesToDoubleTask<K,V>
5702	>	extends BulkTask<K,V,Double> {
5703	>	final ToDoubleFunction<? super V> transformer;
5704	>	final DoubleBinaryOperator reducer;
5705	>	final double basis;
5706	>	double result;
5707	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5708	>	MapReduceValuesToDoubleTask
5709	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5710	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5711	>	ToDoubleFunction<? super V> transformer,
5712	>	double basis,
5713	>	DoubleBinaryOperator reducer) {
5714	>	super(p, b, i, f, t); this.nextRight = nextRight;
5715	>	this.transformer = transformer;
5716	>	this.basis = basis; this.reducer = reducer;
5717	>	}
5718	>	public final Double getRawResult() { return result; }
5719	>	public final void compute() {
5720	>	final ToDoubleFunction<? super V> transformer;
5721	>	final DoubleBinaryOperator reducer;
5722	>	if ((transformer = this.transformer) != null &&
5723	>	(reducer = this.reducer) != null) {
5724	>	double r = this.basis;
5725	>	for (int i = baseIndex, f, h; batch > 0 &&
5726	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5727	>	addToPendingCount(1);
5728	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5729	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5730	>	rights, transformer, r, reducer)).fork();
5731	>	}
5732	>	for (Node<K,V> p; (p = advance()) != null; )
5733	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5734	>	result = r;
5735	>	CountedCompleter<?> c;
5736	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5737	>	@SuppressWarnings("unchecked")
5738	>	MapReduceValuesToDoubleTask<K,V>
5739	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5740	>	s = t.rights;
5741	>	while (s != null) {
5742	>	t.result = reducer.applyAsDouble(t.result, s.result);
5743	>	s = t.rights = s.nextRight;
5744	>	}
5745	>	}
5746	>	}
5747	>	}
5748	>	}
5749	>
5750	>	@SuppressWarnings("serial")
5751	>	static final class MapReduceEntriesToDoubleTask<K,V>
5752	>	extends BulkTask<K,V,Double> {
5753	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5754	>	final DoubleBinaryOperator reducer;
5755	>	final double basis;
5756	>	double result;
5757	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5758	>	MapReduceEntriesToDoubleTask
5759	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5760	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5761	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5762	>	double basis,
5763	>	DoubleBinaryOperator reducer) {
5764	>	super(p, b, i, f, t); this.nextRight = nextRight;
5765	>	this.transformer = transformer;
5766	>	this.basis = basis; this.reducer = reducer;
5767	>	}
5768	>	public final Double getRawResult() { return result; }
5769	>	public final void compute() {
5770	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5771	>	final DoubleBinaryOperator reducer;
5772	>	if ((transformer = this.transformer) != null &&
5773	>	(reducer = this.reducer) != null) {
5774	>	double r = this.basis;
5775	>	for (int i = baseIndex, f, h; batch > 0 &&
5776	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5777	>	addToPendingCount(1);
5778	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5779	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5780	>	rights, transformer, r, reducer)).fork();
5781	>	}
5782	>	for (Node<K,V> p; (p = advance()) != null; )
5783	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5784	>	result = r;
5785	>	CountedCompleter<?> c;
5786	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5787	>	@SuppressWarnings("unchecked")
5788	>	MapReduceEntriesToDoubleTask<K,V>
5789	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5790	>	s = t.rights;
5791	>	while (s != null) {
5792	>	t.result = reducer.applyAsDouble(t.result, s.result);
5793	>	s = t.rights = s.nextRight;
5794	>	}
5795	>	}
5796	>	}
5797	>	}
5798	>	}
5799	>
5800	>	@SuppressWarnings("serial")
5801	>	static final class MapReduceMappingsToDoubleTask<K,V>
5802	>	extends BulkTask<K,V,Double> {
5803	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5804	>	final DoubleBinaryOperator reducer;
5805	>	final double basis;
5806	>	double result;
5807	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5808	>	MapReduceMappingsToDoubleTask
5809	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5810	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5811	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5812	>	double basis,
5813	>	DoubleBinaryOperator reducer) {
5814	>	super(p, b, i, f, t); this.nextRight = nextRight;
5815	>	this.transformer = transformer;
5816	>	this.basis = basis; this.reducer = reducer;
5817	>	}
5818	>	public final Double getRawResult() { return result; }
5819	>	public final void compute() {
5820	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5821	>	final DoubleBinaryOperator reducer;
5822	>	if ((transformer = this.transformer) != null &&
5823	>	(reducer = this.reducer) != null) {
5824	>	double r = this.basis;
5825	>	for (int i = baseIndex, f, h; batch > 0 &&
5826	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5827	>	addToPendingCount(1);
5828	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5829	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5830	>	rights, transformer, r, reducer)).fork();
5831	>	}
5832	>	for (Node<K,V> p; (p = advance()) != null; )
5833	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5834	>	result = r;
5835	>	CountedCompleter<?> c;
5836	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5837	>	@SuppressWarnings("unchecked")
5838	>	MapReduceMappingsToDoubleTask<K,V>
5839	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5840	>	s = t.rights;
5841	>	while (s != null) {
5842	>	t.result = reducer.applyAsDouble(t.result, s.result);
5843	>	s = t.rights = s.nextRight;
5844	>	}
5845	>	}
5846	>	}
5847	>	}
5848	>	}
5849	>
5850	>	@SuppressWarnings("serial")
5851	>	static final class MapReduceKeysToLongTask<K,V>
5852	>	extends BulkTask<K,V,Long> {
5853	>	final ToLongFunction<? super K> transformer;
5854	>	final LongBinaryOperator reducer;
5855	>	final long basis;
5856	>	long result;
5857	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5858	>	MapReduceKeysToLongTask
5859	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5860	>	MapReduceKeysToLongTask<K,V> nextRight,
5861	>	ToLongFunction<? super K> transformer,
5862	>	long basis,
5863	>	LongBinaryOperator reducer) {
5864	>	super(p, b, i, f, t); this.nextRight = nextRight;
5865	>	this.transformer = transformer;
5866	>	this.basis = basis; this.reducer = reducer;
5867	>	}
5868	>	public final Long getRawResult() { return result; }
5869	>	public final void compute() {
5870	>	final ToLongFunction<? super K> transformer;
5871	>	final LongBinaryOperator reducer;
5872	>	if ((transformer = this.transformer) != null &&
5873	>	(reducer = this.reducer) != null) {
5874	>	long r = this.basis;
5875	>	for (int i = baseIndex, f, h; batch > 0 &&
5876	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5877	>	addToPendingCount(1);
5878	>	(rights = new MapReduceKeysToLongTask<K,V>
5879	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5880	>	rights, transformer, r, reducer)).fork();
5881	>	}
5882	>	for (Node<K,V> p; (p = advance()) != null; )
5883	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5884	>	result = r;
5885	>	CountedCompleter<?> c;
5886	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5887	>	@SuppressWarnings("unchecked")
5888	>	MapReduceKeysToLongTask<K,V>
5889	>	t = (MapReduceKeysToLongTask<K,V>)c,
5890	>	s = t.rights;
5891	>	while (s != null) {
5892	>	t.result = reducer.applyAsLong(t.result, s.result);
5893	>	s = t.rights = s.nextRight;
5894	>	}
5895	>	}
5896	>	}
5897	>	}
5898	>	}
5899	>
5900	>	@SuppressWarnings("serial")
5901	>	static final class MapReduceValuesToLongTask<K,V>
5902	>	extends BulkTask<K,V,Long> {
5903	>	final ToLongFunction<? super V> transformer;
5904	>	final LongBinaryOperator reducer;
5905	>	final long basis;
5906	>	long result;
5907	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5908	>	MapReduceValuesToLongTask
5909	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5910	>	MapReduceValuesToLongTask<K,V> nextRight,
5911	>	ToLongFunction<? super V> transformer,
5912	>	long basis,
5913	>	LongBinaryOperator reducer) {
5914	>	super(p, b, i, f, t); this.nextRight = nextRight;
5915	>	this.transformer = transformer;
5916	>	this.basis = basis; this.reducer = reducer;
5917	>	}
5918	>	public final Long getRawResult() { return result; }
5919	>	public final void compute() {
5920	>	final ToLongFunction<? super V> transformer;
5921	>	final LongBinaryOperator reducer;
5922	>	if ((transformer = this.transformer) != null &&
5923	>	(reducer = this.reducer) != null) {
5924	>	long r = this.basis;
5925	>	for (int i = baseIndex, f, h; batch > 0 &&
5926	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5927	>	addToPendingCount(1);
5928	>	(rights = new MapReduceValuesToLongTask<K,V>
5929	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5930	>	rights, transformer, r, reducer)).fork();
5931	>	}
5932	>	for (Node<K,V> p; (p = advance()) != null; )
5933	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5934	>	result = r;
5935	>	CountedCompleter<?> c;
5936	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5937	>	@SuppressWarnings("unchecked")
5938	>	MapReduceValuesToLongTask<K,V>
5939	>	t = (MapReduceValuesToLongTask<K,V>)c,
5940	>	s = t.rights;
5941	>	while (s != null) {
5942	>	t.result = reducer.applyAsLong(t.result, s.result);
5943	>	s = t.rights = s.nextRight;
5944	>	}
5945	>	}
5946	>	}
5947	>	}
5948	>	}
5949	>
5950	>	@SuppressWarnings("serial")
5951	>	static final class MapReduceEntriesToLongTask<K,V>
5952	>	extends BulkTask<K,V,Long> {
5953	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5954	>	final LongBinaryOperator reducer;
5955	>	final long basis;
5956	>	long result;
5957	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5958	>	MapReduceEntriesToLongTask
5959	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5960	>	MapReduceEntriesToLongTask<K,V> nextRight,
5961	>	ToLongFunction<Map.Entry<K,V>> transformer,
5962	>	long basis,
5963	>	LongBinaryOperator reducer) {
5964	>	super(p, b, i, f, t); this.nextRight = nextRight;
5965	>	this.transformer = transformer;
5966	>	this.basis = basis; this.reducer = reducer;
5967	>	}
5968	>	public final Long getRawResult() { return result; }
5969	>	public final void compute() {
5970	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5971	>	final LongBinaryOperator reducer;
5972	>	if ((transformer = this.transformer) != null &&
5973	>	(reducer = this.reducer) != null) {
5974	>	long r = this.basis;
5975	>	for (int i = baseIndex, f, h; batch > 0 &&
5976	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5977	>	addToPendingCount(1);
5978	>	(rights = new MapReduceEntriesToLongTask<K,V>
5979	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5980	>	rights, transformer, r, reducer)).fork();
5981	>	}
5982	>	for (Node<K,V> p; (p = advance()) != null; )
5983	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
5984	>	result = r;
5985	>	CountedCompleter<?> c;
5986	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5987	>	@SuppressWarnings("unchecked")
5988	>	MapReduceEntriesToLongTask<K,V>
5989	>	t = (MapReduceEntriesToLongTask<K,V>)c,
5990	>	s = t.rights;
5991	>	while (s != null) {
5992	>	t.result = reducer.applyAsLong(t.result, s.result);
5993	>	s = t.rights = s.nextRight;
5994	>	}
5995	>	}
5996	>	}
5997	>	}
5998	>	}
5999	>
6000	>	@SuppressWarnings("serial")
6001	>	static final class MapReduceMappingsToLongTask<K,V>
6002	>	extends BulkTask<K,V,Long> {
6003	>	final ToLongBiFunction<? super K, ? super V> transformer;
6004	>	final LongBinaryOperator reducer;
6005	>	final long basis;
6006	>	long result;
6007	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6008	>	MapReduceMappingsToLongTask
6009	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6010	>	MapReduceMappingsToLongTask<K,V> nextRight,
6011	>	ToLongBiFunction<? super K, ? super V> transformer,
6012	>	long basis,
6013	>	LongBinaryOperator reducer) {
6014	>	super(p, b, i, f, t); this.nextRight = nextRight;
6015	>	this.transformer = transformer;
6016	>	this.basis = basis; this.reducer = reducer;
6017	>	}
6018	>	public final Long getRawResult() { return result; }
6019	>	public final void compute() {
6020	>	final ToLongBiFunction<? super K, ? super V> transformer;
6021	>	final LongBinaryOperator reducer;
6022	>	if ((transformer = this.transformer) != null &&
6023	>	(reducer = this.reducer) != null) {
6024	>	long r = this.basis;
6025	>	for (int i = baseIndex, f, h; batch > 0 &&
6026	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6027	>	addToPendingCount(1);
6028	>	(rights = new MapReduceMappingsToLongTask<K,V>
6029	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6030	>	rights, transformer, r, reducer)).fork();
6031	>	}
6032	>	for (Node<K,V> p; (p = advance()) != null; )
6033	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6034	>	result = r;
6035	>	CountedCompleter<?> c;
6036	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6037	>	@SuppressWarnings("unchecked")
6038	>	MapReduceMappingsToLongTask<K,V>
6039	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6040	>	s = t.rights;
6041	>	while (s != null) {
6042	>	t.result = reducer.applyAsLong(t.result, s.result);
6043	>	s = t.rights = s.nextRight;
6044	>	}
6045	>	}
6046	>	}
6047	>	}
6048	>	}
6049	>
6050	>	@SuppressWarnings("serial")
6051	>	static final class MapReduceKeysToIntTask<K,V>
6052	>	extends BulkTask<K,V,Integer> {
6053	>	final ToIntFunction<? super K> transformer;
6054	>	final IntBinaryOperator reducer;
6055	>	final int basis;
6056	>	int result;
6057	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6058	>	MapReduceKeysToIntTask
6059	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6060	>	MapReduceKeysToIntTask<K,V> nextRight,
6061	>	ToIntFunction<? super K> transformer,
6062	>	int basis,
6063	>	IntBinaryOperator reducer) {
6064	>	super(p, b, i, f, t); this.nextRight = nextRight;
6065	>	this.transformer = transformer;
6066	>	this.basis = basis; this.reducer = reducer;
6067	>	}
6068	>	public final Integer getRawResult() { return result; }
6069	>	public final void compute() {
6070	>	final ToIntFunction<? super K> transformer;
6071	>	final IntBinaryOperator reducer;
6072	>	if ((transformer = this.transformer) != null &&
6073	>	(reducer = this.reducer) != null) {
6074	>	int r = this.basis;
6075	>	for (int i = baseIndex, f, h; batch > 0 &&
6076	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6077	>	addToPendingCount(1);
6078	>	(rights = new MapReduceKeysToIntTask<K,V>
6079	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6080	>	rights, transformer, r, reducer)).fork();
6081	>	}
6082	>	for (Node<K,V> p; (p = advance()) != null; )
6083	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6084	>	result = r;
6085	>	CountedCompleter<?> c;
6086	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6087	>	@SuppressWarnings("unchecked")
6088	>	MapReduceKeysToIntTask<K,V>
6089	>	t = (MapReduceKeysToIntTask<K,V>)c,
6090	>	s = t.rights;
6091	>	while (s != null) {
6092	>	t.result = reducer.applyAsInt(t.result, s.result);
6093	>	s = t.rights = s.nextRight;
6094	>	}
6095	>	}
6096	>	}
6097	>	}
6098	>	}
6099	>
6100	>	@SuppressWarnings("serial")
6101	>	static final class MapReduceValuesToIntTask<K,V>
6102	>	extends BulkTask<K,V,Integer> {
6103	>	final ToIntFunction<? super V> transformer;
6104	>	final IntBinaryOperator reducer;
6105	>	final int basis;
6106	>	int result;
6107	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6108	>	MapReduceValuesToIntTask
6109	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6110	>	MapReduceValuesToIntTask<K,V> nextRight,
6111	>	ToIntFunction<? super V> transformer,
6112	>	int basis,
6113	>	IntBinaryOperator reducer) {
6114	>	super(p, b, i, f, t); this.nextRight = nextRight;
6115	>	this.transformer = transformer;
6116	>	this.basis = basis; this.reducer = reducer;
6117	>	}
6118	>	public final Integer getRawResult() { return result; }
6119	>	public final void compute() {
6120	>	final ToIntFunction<? super V> transformer;
6121	>	final IntBinaryOperator reducer;
6122	>	if ((transformer = this.transformer) != null &&
6123	>	(reducer = this.reducer) != null) {
6124	>	int r = this.basis;
6125	>	for (int i = baseIndex, f, h; batch > 0 &&
6126	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6127	>	addToPendingCount(1);
6128	>	(rights = new MapReduceValuesToIntTask<K,V>
6129	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6130	>	rights, transformer, r, reducer)).fork();
6131	>	}
6132	>	for (Node<K,V> p; (p = advance()) != null; )
6133	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6134	>	result = r;
6135	>	CountedCompleter<?> c;
6136	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6137	>	@SuppressWarnings("unchecked")
6138	>	MapReduceValuesToIntTask<K,V>
6139	>	t = (MapReduceValuesToIntTask<K,V>)c,
6140	>	s = t.rights;
6141	>	while (s != null) {
6142	>	t.result = reducer.applyAsInt(t.result, s.result);
6143	>	s = t.rights = s.nextRight;
6144	>	}
6145	>	}
6146	>	}
6147	>	}
6148	>	}
6149	>
6150	>	@SuppressWarnings("serial")
6151	>	static final class MapReduceEntriesToIntTask<K,V>
6152	>	extends BulkTask<K,V,Integer> {
6153	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6154	>	final IntBinaryOperator reducer;
6155	>	final int basis;
6156	>	int result;
6157	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6158	>	MapReduceEntriesToIntTask
6159	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6160	>	MapReduceEntriesToIntTask<K,V> nextRight,
6161	>	ToIntFunction<Map.Entry<K,V>> transformer,
6162	>	int basis,
6163	>	IntBinaryOperator reducer) {
6164	>	super(p, b, i, f, t); this.nextRight = nextRight;
6165	>	this.transformer = transformer;
6166	>	this.basis = basis; this.reducer = reducer;
6167	>	}
6168	>	public final Integer getRawResult() { return result; }
6169	>	public final void compute() {
6170	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6171	>	final IntBinaryOperator reducer;
6172	>	if ((transformer = this.transformer) != null &&
6173	>	(reducer = this.reducer) != null) {
6174	>	int r = this.basis;
6175	>	for (int i = baseIndex, f, h; batch > 0 &&
6176	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6177	>	addToPendingCount(1);
6178	>	(rights = new MapReduceEntriesToIntTask<K,V>
6179	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6180	>	rights, transformer, r, reducer)).fork();
6181	>	}
6182	>	for (Node<K,V> p; (p = advance()) != null; )
6183	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6184	>	result = r;
6185	>	CountedCompleter<?> c;
6186	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6187	>	@SuppressWarnings("unchecked")
6188	>	MapReduceEntriesToIntTask<K,V>
6189	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6190	>	s = t.rights;
6191	>	while (s != null) {
6192	>	t.result = reducer.applyAsInt(t.result, s.result);
6193	>	s = t.rights = s.nextRight;
6194	>	}
6195	>	}
6196	>	}
6197	>	}
6198	>	}
6199	>
6200	>	@SuppressWarnings("serial")
6201	>	static final class MapReduceMappingsToIntTask<K,V>
6202	>	extends BulkTask<K,V,Integer> {
6203	>	final ToIntBiFunction<? super K, ? super V> transformer;
6204	>	final IntBinaryOperator reducer;
6205	>	final int basis;
6206	>	int result;
6207	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6208	>	MapReduceMappingsToIntTask
6209	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6210	>	MapReduceMappingsToIntTask<K,V> nextRight,
6211	>	ToIntBiFunction<? super K, ? super V> transformer,
6212	>	int basis,
6213	>	IntBinaryOperator reducer) {
6214	>	super(p, b, i, f, t); this.nextRight = nextRight;
6215	>	this.transformer = transformer;
6216	>	this.basis = basis; this.reducer = reducer;
6217	>	}
6218	>	public final Integer getRawResult() { return result; }
6219	>	public final void compute() {
6220	>	final ToIntBiFunction<? super K, ? super V> transformer;
6221	>	final IntBinaryOperator reducer;
6222	>	if ((transformer = this.transformer) != null &&
6223	>	(reducer = this.reducer) != null) {
6224	>	int r = this.basis;
6225	>	for (int i = baseIndex, f, h; batch > 0 &&
6226	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6227	>	addToPendingCount(1);
6228	>	(rights = new MapReduceMappingsToIntTask<K,V>
6229	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6230	>	rights, transformer, r, reducer)).fork();
6231	>	}
6232	>	for (Node<K,V> p; (p = advance()) != null; )
6233	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6234	>	result = r;
6235	>	CountedCompleter<?> c;
6236	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6237	>	@SuppressWarnings("unchecked")
6238	>	MapReduceMappingsToIntTask<K,V>
6239	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6240	>	s = t.rights;
6241	>	while (s != null) {
6242	>	t.result = reducer.applyAsInt(t.result, s.result);
6243	>	s = t.rights = s.nextRight;
6244	>	}
6245	>	}
6246	>	}
6247	>	}
6248	>	}
6249	>
6250	>	// Unsafe mechanics
6251	>	private static final sun.misc.Unsafe U;
6252	>	private static final long SIZECTL;
6253	>	private static final long TRANSFERINDEX;
6254	>	private static final long BASECOUNT;
6255	>	private static final long CELLSBUSY;
6256	>	private static final long CELLVALUE;
6257	>	private static final long ABASE;
6258	>	private static final int ASHIFT;
6259	>
6260	>	static {
6261	>	try {
6262	>	U = sun.misc.Unsafe.getUnsafe();
6263	>	Class<?> k = ConcurrentHashMap.class;
6264	>	SIZECTL = U.objectFieldOffset
6265	>	(k.getDeclaredField("sizeCtl"));
6266	>	TRANSFERINDEX = U.objectFieldOffset
6267	>	(k.getDeclaredField("transferIndex"));
6268	>	BASECOUNT = U.objectFieldOffset
6269	>	(k.getDeclaredField("baseCount"));
6270	>	CELLSBUSY = U.objectFieldOffset
6271	>	(k.getDeclaredField("cellsBusy"));
6272	>	Class<?> ck = CounterCell.class;
6273	>	CELLVALUE = U.objectFieldOffset
6274	>	(ck.getDeclaredField("value"));
6275	>	Class<?> ak = Node[].class;
6276	>	ABASE = U.arrayBaseOffset(ak);
6277	>	int scale = U.arrayIndexScale(ak);
6278	>	if ((scale & (scale - 1)) != 0)
6279	>	throw new Error("data type scale not a power of two");
6280	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6281	>	} catch (Exception e) {
6282	>	throw new Error(e);
6283		}
6284		}
6285		}

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